CONTROL FOR FLOOR SCRAPING MACHINE

Description

CROSS-REFERENCED TO RELATED APPLICATIONS

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to machines for stripping, by scraping, materials such as adhesive bonded floor coverings from floor surfaces. Such machines are commonly referred to as “floor scrapers” or “floor strippers.” Such machines may be ride-on or walk behind machines.

2. Discussion of the Prior Art

In 2009, Martin L. Anderson was awarded U.S. Pat. No. 7,562,412 entitles “Blade Position Control for Ride-on Floor Scraping Machine.” The machine disclosed in that patent includes a rear housing section having a pair of rear wheels and a motor for driving each of the rear wheels, a motor section attached to the front of the rear housing section, and an adjustable blade assembly. The adjustable blade assembly comprises a bracket attached to the front of the motor section, a vertically adjustable plate positioned generally perpendicular to the floor surface and held by the bracket, a blade holder, and a hinge attached at the base of the vertically adjustable plate for pivotally connecting the blade holder to the vertically adjustable plate. A blade is attached directly to the blade holder. In some embodiments, the blade holder includes a first component attached by a hinge to the vertically adjustable plate, a second component to which the blade is attached, and a rod member and collar to rotatably connect the first and second components together.

Various types of blades may be used during operation of the above referenced machine including, without limitation, blades of the type shown in Anderson's U.S. Pat. No. 7,562,412, the various angled shank blades shown in Anderson's U.S. Pat. Nos. 6,813,834 and 7,082,686, winged blades shown in U.S. Pat. No. 10,941,529 granted to Bigham et al on Mar. 9, 2021, and blades of the type shown in U.S. Pat. No. 11,085,195 granted to Burk on Aug. 10, 2021.

The adjustable blade assembly of the above referenced machine further comprises a first linear actuator (e.g., a hydraulic cylinder) to rotate the blade holder about the hinge relative to the vertically adjustable plate. This first linear actuator also holds the blade holder at a desired angle relative to the vertically adjustable plate. The adjustable blade assembly may also include a second linear actuator. This second linear actuator is employed to position and hold the vertically adjustable plate at a desired height relative to the bracket attached to the motor section of the machine.

The linear actuators of the blade holder assembly of the above referenced machine are controlled manually by an operator to adjust the angle of attack of a scraping blade. The machine's ability to remove material efficiently and effectively from the floor is dependent on the angle of attack set by the operator. The optimal angle of attack of the blade is dependent on various factors including the material to be removed from the floor, e.g., carpet, ceramic tile, hardwood, vinyl tile, stone, adhesive, etc., the type of blade attached to the machine, and the weight of the motor section which adds weight to the front of the floor scraping machine to increase the effectiveness of the floor scraping blade. Use of an improper angle of attack often results in inefficiencies when scraping and expedited wearing (dulling) of blades.

A skilled, experienced operator familiar with the above referenced machine and its operation is able to separately adjust the two linear actuators to achieve a suitable angle of attack. However, adjusting the linear actuators to achieve the optimal angle of attack can be time consuming even for highly skilled and experienced operators. Unskilled, inexperienced operators can find this task quite daunting. Further, if the blade is not properly positioned for scraping with the front caster elevated sufficiently from the floor, the casters can become damaged during the scraping operation. A significant factor leading to this difficulty and such damage is not being able to readily discern where and how the blade and casters are positioned. Thus, there currently exists a real need for a machine that can automatically identify for the operator the position of the blade in real time, automatically identify for the operator if the casters are elevated from the floor, automatically operate the linear actuators to set the blade at a preferred angle of attack based at least on the flooring material to be removed, or some combination of the foregoing. There is also a need for machines that can automatically operate the machine in view of other factors such as the type of blade being used, and the amount of auxiliary weight added to the machine.

Further, such machines need to be narrow enough to fit through standard doorways and powerful enough to plow through and lift floor coverings from the floor. When in use, the front of the machine is often supported solely by the blade so that the machine can supply maximum downward force to the blade. This combination of needs has, in the past, resulted in machines that are difficult for inexperienced riders to control. Thus, there also exists a real need to provide a machine that both experienced users and novices find easy to maneuver.

SUMMARY OF THE INVENTION

The present invention relates to floor strippers. Various embodiments of the invention comprise a drive section, a blade positioning assembly, a control assembly, and a user interface.

The drive section of floor strippers typically includes at least one wheel rotated by a motor to move the machine across the floor. Most machines have two such wheels. Machines having two such wheels are typically turned either left or right by rotating the wheels at different speeds or in different directions. These wheels support a frame which, in turn, supports other components of the machine.

The blade positioning assembly is coupled to the drive section and enables a blade attached to a blade holder of the blade positioning assembly to be rotated relative to the drive section. In some embodiments, the blade positioning assembly comprises a hinge rotatably coupling a blade holder to the drive section. In other embodiments, the blade positioning assembly comprises a bracket attached to the drive section, a vertically adjustable plate configured to slide up and down vertically relative to the bracket, and a blade holder pivotally connected to the vertically adjustable plate by a hinge. In still other embodiments, the blade positioning assembly includes a linkage, such as a four-bar linkage, rotatably coupling a blade holder either directly to the drive section or to a vertically adjustable plate configured to slide up and down relative to a bracket attached to the drive section.

The control assembly includes a blade sensor configured to send position signals in real time corresponding to the position of the blade holder, a load or position sensor configured to send signals indicating whether the casters are elevated from the floor, and at least one actuator assembly configured to receive actuator control signals and, based on said actuator control signals, rotate the blade holder into, and then hold the blade holder at, a preferred angle of attack for a blade held by the blade holder. In some embodiments, the control assembly also includes a controller.

When the blade holder is coupled directly to the drive section by a hinge or linkage of a blade positioning assembly, a single actuator assembly may be provided. This single actuator assembly may comprise a linear actuator coupled at one of its ends to the drive section and at the other of its ends to the blade holder or some other link of the linkage. Alternatively, this single actuator assembly may comprise a rotary actuator proximate the hinge or a hinged joint of the linkage.

When the blade holder is coupled to the drive section via a bracket and vertically adjustable plate, two actuator assemblies may be provided, i.e., a first actuator assembly for raising, lowering, and holding the vertically adjustable plate in a desired position, and a second actuator assembly for rotating and holding the blade holder at a desired angle relative to the vertically adjustable plate and drive section. The first and second actuator assemblies each comprise an actuator which may be a linear actuator or a rotary actuator. In such embodiments, an additional position sensor is provided to sense the position of the vertically adjustable plate relative to the bracket.

Different types of actuator assemblies may be employed as either the first or the second actuator assemblies. The actuator assemblies may include a hydraulic cylinder or hydraulic motor, together with valves, and valve actuators (e.g., solenoids) controlling the length of the hydraulic cylinder or rotational position of the hydraulic motor. Alternatively, electro-mechanical linear actuators, such as those having a lead screw, a nut assembly and a motor configured to drive the lead screw, may be used. The motor may be an electric motor such as a de brush motor, dc brushless motor, stepper motor, induction motor or servo motor. Rotary electro-mechanical actuators may also be employed.

The control assembly may additionally include motor(s) for driving the wheel(s). For example, the control assembly may include a first wheel motor assembly configured to receive first wheel control signals and drive a first wheel of the pair of wheels, a second wheel motor assembly configured to receive second wheel control signals and drive a second wheel of the pair of wheels, a first wheel sensor configured to send in real time first wheel signals indicative of the speed and direction of rotation of the first wheel, and a second wheel sensor configured to send in real time second wheel signals indicative of the speed and direction of rotation of the second wheel.

Different types of wheel motor assemblies may be used. In some embodiments, the motor assemblies may each include a rotary hydraulic motor, valves and valve actuators uses to control the rate and direction of the flow of hydraulic fluid from a motor driven pump through the hydraulic motor, and thus the speed and direction of rotation of the motor's output shaft and the wheel coupled to the motor's output shaft. In other embodiments, the wheel motor assemblies comprise a variable speed electric motor and circuitry configured to process control signals to regulate the speed and direction of the motor's output shaft.

Different types of sensors may be employed as position sensors and wheel sensors. Examples include inductive sensors, Hall Effect sensors, magneto-resistive sensors, and optical sensors.

The user interface includes at least one operator actuated control assembly configured to send a set of operator input signals. Such operator input signals may be indicative of the flooring type to be removed, the type of blade attached to the machine, the weight of the machine, or some other factor the controller should consider when determining a preferred angle of attack for the blade. These operator input signals may be used by a controller, in combination with signals received from the position sensor(s), to generate the actuator control signals to the actuator(s) and thereby set the angle of attack of a blade coupled to the blade holder. In some embodiments, the control assembly and the user interface cooperate not only to adjust the angle of attack of the blade, but also to separately control the speed and direction of rotation of each wheel. Thus, the user assembly may also include additional operator actuator control assemblies allowing the user to control the speed and direction of the machine.

The user interface may include one or more displays. Simple seven segment alpha-numeric displays may be used in some embodiments. In other embodiments a simple graphical display is used. For example, in embodiments employing a single actuator to adjust the angle of the blade holder and a single sensor configured to generate signals indicative of that angle, an LCD display element comprising a plurality of LEDs arranged in a line or arc may be used to display a scale equating to an angle of the blade/blade holder. One or more LEDs of a particular row are illuminated by the display's controller based on sensor signals received to provide an indication of the angle. In embodiments including two actuators and two position sensors, one indicating the position of the vertically adjustable plate and another indicating the angle of the blade holder relative to the vertically adjustable plate, the display may include two rows of LEDs, one row having one or more LEDs illuminated by the display's controller to indicate the position of the vertically adjustable plate, and another having one or more LEDs illuminated by the display's controller to indicate the angle of the blade holder. Alternatively, the LED display may include one or more rows of multi-colored LEDs, one color generated by the illuminated LEDs of a row being used to indicate the position of the vertically adjustable blade plate while a second color generated by the illuminated LEDs of a row being used to indicate the angle of the blade holder/blade relative to the vertically adjustable plate. These same displays, a separate display, an indicator light, or audible alarm may be used to indicate whether the casters are in contact with or elevated from the floor based on the signals generated by a sensor associated with the caster(s). This sensor may be a pressure, proximity or position sensor, or a sensor in the form of a switch that is configured to be closed when the caster is in contact with the floor and open when the caster is raised from the floor. In still other embodiments, a capacitive or resistive touch screen that displays information based on signals received from the controller and delivers signals to the controller based on “touch events.” Such screens are currently used on smart phones, tablet computers, laptop computers, automobiles, and a variety of consumer products. The controller may be programmed to cause the touch screen to display various selectable options, and further programmed to process touch events corresponding to the selected options. Such options, for example, may include options relating to types of material to be removed from the floor, blade types used with the machine, the total weight of auxiliary weights attached to the machine, a desired maximum speed of the machine, a desired maximum rate of acceleration, or other options related to the user, the machine, or the project with which the machine is being used.

Alternatively, or additionally, the user interface may comprise one or more switches. In some embodiments, a switch may be provided to send a signal to a controller instructing the controller to store the then current position of the blade, and that switch (or a second switch) can then be used to send a signal to the controller instructing the controller to restore the blade to the stored position after the blade has been moved from the stored position to a different position, such as during replacement of the blade. In some embodiments, multi-position switches, e.g., rotary switches, each having a plurality of switch positions. For example, the individual switch positions of one multi-position switch may correspond to different types of flooring materials that the machine can strip from a floor, each of said switch positions corresponding to different type of flooring material, e.g., carpet, ceramic tile, vinyl, or stone. Likewise, the individual switch positions of a multi-position switch may correspond to different types of blades, each of said switch positions corresponding to a different blade type. In still other embodiments, multi-position switches may be used to select a desired maximum rate of acceleration, a desired maximum speed, the number of auxiliary weights attached to the machine, or other parameters relating to use of the machine.

In still other embodiments, the user interface may include a plurality of sets of switches. The individual sets may be used to identify various parameters including, among others, the type of flooring being removed, the type of blade attached to the machine, the maximum acceleration rate for the machine, or the maximum speed of the machine.

The wheel motor assemblies of some embodiments may be configured to receive control signals from the controller. In such cases, the user interface includes an operator actuated control assembly configured to respond to actions by the user and send signals to the controller indicative of a desired speed and direction of the machine. For example, an operator actuated control assembly of the user interface may include a joystick and even a mechanism for adjusting the sensitivity of the joystick. Such a sensitivity adjustment mechanism may also be used to adjust the sensitivity of other user operated controls.

The optimal range of speeds within which the machine should be operated may be impacted by the type of blade attached to the machine, the blade's angle of attack, the type of material to be removed from the floor, and/or the training and experience of the user. Machines employing wheel motor assemblies controlled by the controller may be configured to control the speed of the machine based on these factors. The range within which the machine may be accelerated may similarly be controlled.

As should be clear from the forgoing, the controller can identify the type of material to be removed, the type of blade attached to the machine, and the amount of auxiliary weigh added to the machine via inputs received from the user interface. Alternatively, the machine may be provided with a sensor (e.g., an optical sensor) and the controller with logic that allows the machine to identify the type of flooring lying beneath or in front of the machine. The machine may also be provided with a blade sensor and the blades may be embedded or otherwise labeled with a blade type code. In such cases, the blade's code is configured to be read by the blade sensor positioned, for example, on the blade holder which sends signals to the controller. A sensor may also be used to identify the number of auxiliary weights (or the total of the added auxiliary weight) added to the machine. The controller can use the signals from such sensors to identify the desired angle of attack of the blade and send corresponding control signals to the actuator(s). The controller can also use these signals as it governs the speed (or acceleration) of rotation of the wheel(s) based on a programmed set of instructions.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing features, objects and advantages of the invention will become apparent to those skilled in the art from the following detailed description and with reference to the following drawings in which like numerals in the several views refer to corresponding parts.

FIG. 1 is a perspective view of a floor stripping machine.

FIG. 2 is a perspective view of the blade positioning assembly of the floor stripping machine of FIG. 1 with the linear actuators of the blade positioning assembly each fully retracted.

FIG. 3 is a perspective view of the blade positioning assembly of the floor stripping machine of FIG. 1 with the linear actuators of the blade positioning assembly each fully extended.

FIG. 4 is an exploded perspective view of the blade positioning assembly of the floor stripping machine of FIG. 1.

FIG. 5 is a schematic diagram of a first embodiment of a control assembly configured for controlling the blade positioning assembly of the floor stripping machine of FIG. 1.

FIG. 6 is a schematic hydraulic diagram illustrating the components controlled by the control assembly of FIG. 5.

FIG. 7 is an alternative schematic hydraulic diagram illustrating the components controlled by the control assembly of FIG. 5 wherein the user interface includes a knob for controlling the speed of the motor powering the pumps.

FIG. 8 is a schematic diagram of a second embodiment of a control assembly configured for controlling the blade positioning assembly of the floor stripping machine of FIG. 1.

FIG. 9 is a side view of a first angled shank blade having a pair of external ring electrodes located on the shank of the blade.

FIG. 10 is a perspective view of a second angled shank blade having a series of magnets coupled to the shank of the blade.

FIG. 11 shows a wing style blade having a bar code engraved into its upper surface.

FIG. 12 shows the wing style blade of FIG. 11 coupled to a blade holder, the blade holder being attached to the socket of a pivoting plate of the machine, said pivoting plate of the machine including a sensor configured to read the bar code on the wing style blade.

FIG. 13 is a flow chart illustrating how the controller of the control assembly of FIG. 8 may be programmed to operate.

FIGS. 14 through 17 is a flow chart illustrating an alternative way the controller of the control assembly of FIG. 8 may be programmed to operate.

FIG. 18 shows an alternative embodiment of the blade positioning assembly with the blade angled with respect to the plane of a floor.

FIG. 19 shows the alternative embodiment of the blade positioning assembly of FIG. 18 with the blade in a position substantially parallel to the plane of the floor.

FIGS. 20 through 23 are perspective views illustrating how auxiliary weights in a canister may be coupled to and removed from the machine.

FIGS. 24 and 25 are schematic diagrams illustrating blade position sensor(s) coupled to a display of a user interface such that the display provides information to the user related to blade position.

FIG. 26 is a schematic diagram illustrating an embodiment in which an existing position of the blade can be stored and later, after the blade has been moved, restored.

FIG. 27 is a perspective view of a walk behind floor scraper that may be equipped to take advantage of the present invention,

FIG. 28 is a blown apart perspective view of the walk behind scraper of FIG. 27.

FIG. 29 is a perspective view of the blade assembly of the walk behind scraper of FIG. 27.

FIG. 30 is a schematic diagram illustrating an application of sensors and display features with which the walk behind scraper of FIG. 27 may be configured.

FIG. 31 is a schematic diagram illustrating an application of sensors, and controller, and display features with which the walk behind scraper of FIG. 27 may be configured.

DETAILED DESCRIPTION

This description of the preferred embodiment is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description of this invention. In the description, relative terms such as “lower”, “upper”, “horizontal”, “vertical”, “above”, “below”, “up”, “down”, “top” and “bottom”, “under”, as well as derivatives thereof (e.g., “horizontally”, “downwardly”, “upwardly”, “underside”, etc.) should be construed to refer to the orientation as then described or as shown in the drawings under discussion. These relative terms are for convenience of description and do not require that the apparatus be constructed or operated in a particular orientation. Terms such as “connected”, “connecting”, “attached”, “attaching”, “joined”, and “joining” are used interchangeably and refer to one structure or surface being secured to another structure or surface or integrally fabricated in one piece unless expressly described otherwise.

A self-propelled ride-on machine 1 for stripping floor coverings from floor surfaces is shown generally in FIGS. 1 through 12. Machine 1 includes drive section 2, a blade positioning assembly 3, a blade 4, a user interface 5, and a control assembly 6. Drive section 2 comprises a frame 10 supported by a pair of drive wheels 12 and 14. A pair of caster wheels 13 are also located at the front of the drive section. Blade positioning assembly 3 comprises a bracket 20 attached the drive section 2, a vertically adjustable plate 22 held by bracket 20 generally perpendicular to the floor to be stripped, a blade holder 24, and a hinge 26 pivotally connecting vertically adjustable plate 22 and blade holder 24. Blade 4 is coupled to the blade holder 24 by blade holder bracket 28 which may include a support rod 29 journaled for rotation within a receiver socket 30 of the blade holder 24.

Control assembly 6 comprises a controller 40 configured to receive and process signals from the user interface 5 and various sensors and send control signals to various devices. These sensors may include two position sensors 42 and 44. Position sensor 42 is configured to sense the vertical position of vertically adjustable plate 22. Position sensor 44 is configured to sense the angle of blade holder 24 relative to vertically adjustable plate 22. In alternative embodiments not including the vertically adjustable plate 22, the blade holder 24 may be attached to the front of the drive section 2 by a hinge or linkage. In such alternative embodiments, position sensor 42 may be eliminated and sensor 44 is then used to sense the angle of the blade holder 24 relative to drive section 2. An alternative or additional sensor 45 for sense this angle is also shown. Different types of sensors may be employed as position sensors 42 and 44/45. Examples include inductive sensors, Hall Effect sensors, magneto-resistive sensors, and optical sensors.

In some embodiments, a sensor 43 is employed to generate signals indicative of whether the caster wheels 13 at the front to the machine are engaged with the floor. Sensor 43 can be a proximity, position sensor, or pressure sensor, or even a switch that is closed when the caster wheels are engaging the floor and otherwise open.

In some embodiments, control assembly 6 includes a first wheel sensor 46 configured to sense the speed and direction of rotation of wheel 12 and a second wheel sensor 48 configured to sense the speed and direction of rotation of the wheel 14. In still other embodiments, other sensors are provided, e.g., sensors 47, 49 and 50 shown in FIG. 8. Sensor 47 may be a sensor used to generate signals indicative of the amount of auxiliary weight or the number of auxiliary weights added to machine 1. Sensor 49 may, for example, be an optical or image sensor directed beneath or in front of the machine that sends signals to the controller 40 which the controller processes to ascertain the type of flooring to be removed. As explained further below, sensor 50 may be used to send signals to the controller related to the blade attached to the blade holder 24.

Various types of blades 4 may be used during operation of the machine including, without limitation, blades of the type shown in Anderson's U.S. Pat. No. 7,562,412, the various angled shank blades shown in Anderson's U.S. Pat. Nos. 6,813,834 and 7,082,686, winged blades shown in U.S. Pat. No. 10,941,529 granted to Bigham et al on Mar. 9, 2021, and blades of the type shown in U.S. Pat. No. 11,085,195 granted to Burk on Aug. 10, 2021. Examples of such blades 4 are also shown in FIGS. 9-12. As shown in FIGS. 9-12, an indicator identifying information related to the blade may be attached to blade 4 at the factory or elsewhere. Such information may include the type of blade, the manufacturer of the blade, the date of manufacture and lot number of the blade, the serial number of the blade, or the like. The indicator may be, for example, (a) a radio frequency identification (RFID) tag, (b) a code (e.g., a barcode 51, a QR code, etc.) stamped, engraved, etched, or printed on the blade or a separate label or tag affixed to the blade, (c) a set of magnets 102 (i.e., permanent magnets, temporary magnets, or electromagnets) embedded into and coupled to the blade or a shank or rod 29 permanently attached to the blade 4, or (d) a circuit embedded in the blade and configured to transmit, in either a wired or wireless fashion, to the controller a unique signal indicative of the type of blade. Such a circuit may transmit signals identifying the blade and the blade's type in a wired fashion via ring electrodes 104 and 105 on the surface of the shank of an angled shank blade as shown in FIG. 9.

The control assembly therefore may include blade sensor 50 configured to “read” the code provided by the indicator of the blade 4. As such, sensor 50 may be an optical sensor as shown in FIG. 12 configured to read a bar code, QR code or the like. Sensor 50 may be an RFID reader when an RFID tag or circuit is attached to the blade 4. Sensor 50 may be a Hall Effect or magneto-resistive sensor to generate signals based on the location/arrangement of the magnets 102 of FIG. 10. Sensor 50 may also be a Wi-Fi or Bluetooth transceiver if a corresponding Wi-Fi or Bluetooth transmitter is embedded in or coupled to the blade and configured to transmit blade type identification signals. Sensor 50 may also be electrical contacts in the socket 30 of the blade holder 24. In this example, these electrical contacts are coupled to an input port of the controller 40 and are configured to contact the ring electrodes 104/105 of FIG. 9. A circuit is thus completed between controller 40 and an identification circuit embedded in blade 4.

Control assembly 6 includes various devices that are controlled by controller 40 in accordance with a predetermined set of instructions and based on signals the controller 40 receives from the user interface 5 and the various sensors. These devices may be electromechanical or hydraulic.

In some embodiments, a first actuator assembly 60 comprises a linear actuator connected to the blade holder 24. Actuator assembly 60 is configured to receive the first actuator control signals from the controller 40. Based on these first actuator control signals, actuator assembly 60 rotates the blade holder 24 about the hinge 26 relative to the vertically adjustable plate 22 (or the drive section in embodiments not including the vertically adjustable plate 22) and then hold the blade holder 24 at a desired angle relative the vertically adjustable plate 22 (or the drive section).

This linear actuator of actuator assembly 60 may be replaced by a rotary actuator assembly without deviating from the invention. The rotary actuator assembly may be an electro-mechanical rotary actuator or a hydraulic rotary actuator. Either type of rotary actuator typically includes a motor coupled to an output shaft configured to rotate the blade holder 24, i.e., an electric motor in the case of an electro-mechanical rotary actuator or a hydraulic motor in the case of a hydraulic rotary actuator. An electro-mechanical rotary actuator will typically be a stepper motor or a servo motor that receives control signals from the controller and delivers position feedback signals to the controller indicative of blade position. A hydraulic rotary actuator will typically include a servo valve, or a pair of solenoid-controlled valves, to control the angular position of the impeller and shaft, and an angular feedback sensor sending position feedback signals to the controller indicative of blade position.

In other embodiments, the blade positioning assembly 3 comprises a linkage having a movable component to which the blade holder 24 and blade 4 are coupled. In these embodiments, the actuator of the first actuator assembly 60 is connected to either a vertically adjustable plate 22, or to a fixed portion of the frame 10 of the vehicle, and to a movable component of the linkage. An example of such a linkage is shown in FIGS. 18 and 19. As shown, the linkage 110 is a four-bar linkage comprising a fixed link 112 configured to be coupled and fixed to either the front of the frame 10 or to vertically adjustable plate 22. Separately and pivotally coupled at their first ends to the fixed link 112 are an input link 114 and an output link 116. In this example, the blade holder 24 is separately and pivotally coupled to the second ends of the input link 114 and output link 116 and acts as an intermediate link. The linear actuator of actuator assembly 60 is coupled to the input link 114. Thus, extension and retraction of the linear actuator causes the blade holder 24 and attached blade 4 to move between the positions shown in FIGS. 18 and 19. And the blade holder 24 and blade are infinitely adjustable between these two positions. In this embodiment, the blade position sensor is a sensor 118 that senses the position (e.g., extension) of the actuator assembly 60. As should be clear from the foregoing, the position of the actuator assembly 60, working in conjunction with the linkage 110, sets the position of the blade holder 24 and blade 4 attached to the blade holder. Further, the linear actuator could be replaced by a rotary actuator configured to rotate an input link relative to blade holder 24.

In some embodiments, control assembly 6 may include a second actuator assembly 62 comprising an actuator connected to the vertically adjustable plate 22 and to the drive section 2 or bracket 20. The second actuator assembly 62 is configured to receive second control signals from controller 40. Based on these second control signals, the actuator of actuator assembly 62 vertically adjusts the position of the vertically adjustable plate 22 and cooperates with bracket 20 to hold the vertically adjustable plate 22 at a desired position.

Different types of linear actuators may be employed as part of the first actuator assembly 60 or the second actuator assembly 62. Hydraulic cylinders may be used. When hydraulic actuators are used, the first and second actuator assemblies 60 and 62 each also include solenoids (or similar devices) operating multi-port valves 90 and 92 that control the flow of hydraulic fluid to and/or from the hydraulic actuators in response to the first and second actuator control signals. Alternatively, electro-mechanical actuators, such as those having a lead screw, a nut assembly and an actuator motor configured to drive the lead screw, may be used. The actuator motor may be a direct current brush motor, a direct current brushless motor, an induction motor, a stepper motor, or a servo motor. When electro-mechanical actuators are used, the first and second actuator assemblies 60 and 62 each also include circuitry configured to process control signals received from the controller 40 and regulate the speed and direction of the motor in response to such control signals. When a servo motor or a stepper motor is used, the encoder of the motor may serve as the associated position sensor 42/44.

The drive section of a ride-on floor strippers typically includes at least one wheel rotated by a motor to move the machine across the floor. When only one wheel is used, the wheel is a caster wheel driven by a wheel motor and steered by an actuator coupled to the wheel by a linkage or in some other suitable manner. The wheel motor and this actuator are each responsive to control signals generated by the controller in response to inputs received from the user interface and thereby control the speed and direction of the machine.

The drawings show the drive section 2 having two wheels 12/14 and separate wheel motor assemblies 64 and 66. First wheel motor assembly 64 is configured to rotate wheel 12 in either a clockwise or counterclockwise direction and second wheel motor assembly 66 is configured to rotate wheel 14 in either a clockwise or counterclockwise direction. As such, machine 1 is turned either left or right by rotating the wheels 12/14 at different speeds or in different directions. In some embodiments, these wheel motor assemblies 64 and 66 may be configured to receive control signals from the controller 40. In such embodiments, user interface 5 may be configured to respond to actions by the user indicative of a desired speed and direction of the machine 1 and send corresponding signals to controller 40. Distinct types of wheel motor assemblies may be employed. Wheel motor assemblies 64 and 66 may each include a hydraulic motor, in which case the wheel motor assemblies will also include solenoids (or similar actuators) configured to control multi-port valves (e.g., 91 and 93) that regulate the direction and rate of flow of hydraulic fluid to and/or from the hydraulic motors and thus the direction and rate of rotation of the wheels coupled to the wheel motor assemblies. Such a hydraulic drive system will also include a main motor 95 powering pumps 96 and 97. The hydraulic circuit will also include a fluid reservoir, filters 98, and relief valves 99. Alternatively, the first wheel motor assembly 64 and the second wheel motor assembly 66 may each comprise an electric motor. These electric motors may be direct current brush motors, direct current brushless motors, induction motors, stepper motors, or servo motors. When electric motors are used, the wheel motor assemblies 64 and 66 each also include circuitry configured to process control signals received from the controller 40 and regulate the speed and direction of the motor in response to such control signals. When servo motors or stepper motors are used, the encoders of the motors may serve as wheel sensors 46/48.

User interface 5 will include a plurality operator actuated control assemblies. As shown in FIG. 8, the operator actuated control assemblies may include a joystick 7, a touch display 8, one or more multi-position switches 100, one or more sets of toggle switches 101, or combinations of the forgoing. The touch display 8 may be a capacitive or resistive touch display that displays information based on signals received from the controller 40 and delivers signals to the controller 40 based on “touch events.” Such screens are used on smart phones, tablet computers, laptop computers, automobiles, and a variety of consumer products. The controller 40 may be programmed to cause the touch screen 8 to display selectable options related to operation of the machine and, and further programmed to process touch events corresponding to the selected options selected by the user. Alternatively, or additionally, such options may be selected using either the multi-position switches 100 or the sets of toggle switches 101.

For example, the individual switch positions of one multi-position switch 100 may correspond to different types of materials that the machine can strip from a floor. Likewise, the individual switch positions of a different multi-position switch 100 may correspond to different types of blades that may be attached to the machine to strip from a floor, each of said switch positions corresponding to a different blade type. The individual switch positions of a multi-position switch 100 may also correspond to a maximum speed or maximum rate of acceleration at which machine 1 will operate, the number of auxiliary weights or amount of auxiliary weight attached to the machine, or virtually any other factor that may affect performance.

As shown in FIG. 8, an operator actuated control assembly of user interface 5 may also include a joystick 7 (e.g., a Hall Effects joystick). Joystick 7 may be manipulated by a user to send signals to the controller indicative of the user's desired speed and direction of machine 1. The wheel sensors 46/48 (e.g., Hall Effect sensors) generate and send to the controller 40 feedback signals indicative of the actual speed at which the wheels 12/14 are rotation. Controller 40 is configured to process signals received from the joystick and wheel sensors (and potentially other sensors and other operator actuated control assemblies) in accordance with a programmable set of instructions to generate and sent to the wheel motor assemblies 64/66 control signals for controlling the speed and direction of rotation of the wheels 12/14. The sensitivity of the joystick 7 may also be adjusted in various ways using touch display 8, a multi-position switch 100 or a set of toggle switches 101.

The operation of machine 1 will now be described with reference to FIG. 13. In FIG. 13, the dashed arrows are used to indicate steps may be skipped depending on the sensors and actuators of the specific embodiment of the machine. The upwardly facing arrows indicate feedback signals received from the sensors 42/44 and 46/48.

The machine is powered on at step 70. Controller 40 then seeks to ascertain the type of flooring material to be removed at step 72. When user interface 5 includes touch screen 8, the controller sends commands to touch screen 8 causing touch screen 8 to display the available flooring type options. When the user selects one of the options, a corresponding signal is sent by touch display 8 to the controller 40. If the user interface 5 includes a dial or switches (e.g., multi-position switches 100 or toggle switch sets 101) for the user to employ to identify the flooring material to be removed, the user interface 5 generates a signal to a display or other indicator directing the user to select a flooring material type and the checks the status/position of the dial or those switches. If the machine includes a flooring type sensor 49, signals from that sensor may be used by the controller 40 to ascertain the type of flooring to be removed.

At step 74, the controller seeks to ascertain the type of blade attached to the machine 1. When the user interface includes touch screen 8, the controller sends commands to the touch screen causing the touch screen to display the available blade options. When the user selects a blade option, a corresponding signal is sent by touch display 8 to the controller 40. If the user interface 5 includes a dial or switches (e.g., multi-position switches 100 or toggle switch sets 101) for the user to employ to identify the blade type, the user interface generates a signal to a display or other indicator directing the user to select a blade type and the checks the status/position of the dial or those switches used to signal blade type. As noted above, some embodiments may include a blade type indicator on the blade 4 and a corresponding blade type sensor 50. At step 74 the controller 40 automatically sets the blade type based on the signals received from sensor 50.

The controller 40 may be programmed to respond to the flooring type and/or blade type information in various ways. First, the controller 40 can ascertain whether the attached blade 4 is suitable for use given the flooring type. If not, the controller 40 can issue a signal to the display of touch screen 8 (or some other display or indicator) advising the user to exchange the blade 4 for a blade of suitable type and even recommend the type of blade to be used. Second, controller 40 can ascertain whether the blade attached is even authorized for use with machine 1. If not, the controller 40 can suspend further operation of the machine until an authorized blade is attached, or signal the user that use of the attached blade may be dangerous, void any warrantees, or void the terms of use in a rental agreement. If desired, the user may also be given the opportunity to acknowledge the warning and proceed to operate the machine with the acknowledgement, along with the identity of the user making the acknowledgement and its date and time, stored in the memory of the controller 40. Alternatively, the user may be required to enter an authorization code provided by the machine manufacturer or the machine's owner.

At step 76, controller 40 uses the flooring type and blade type (and perhaps other data such as data related to auxiliary weights) to ascertain a recommended angle of attack for the blade. At step 78, the controller ascertains the current angle of blade holder 24 relative to the vertically adjustable blade plate 22 based on signals received from position sensor 44 and at step 80 sends control signals to actuator assembly 60 to adjust this angle, as necessary. If the machine 1 also has a linear actuator as part of the actuator assembly 62 and a position sensor 42, the controller performs step 82 to ascertain the height of the vertically adjustable blade plate 22 and step 84 during which controller 40 sends control signals to linear actuator of actuator assembly 62 to adjust the position of vertically adjustable blade plate 22, as necessary. The controller continues to make such adjustments until the desired attack angle for the blade 4 is reached.

At step 86, a desired maximum speed and/or maximum rate of acceleration can be set given the operating conditions, e.g., blade type, flooring material type, attack angle, and/or other user definable (or user specific) parameters.

At step 88, the controller 40 switches from the setup mode described above to an operate mode. In the operate mode, the user employes the joystick or other controls of the user interface 5 to send signals to the controller 40. In accordance with a predetermined set of instructions, the controller uses the signals from the user interface 5, and the wheel sensors 46 and 48, to send signals to the wheel motor assemblies comprising motors 64 and 66 to control the speed and direction of the machine 1. At the same time, controller 40 continues monitoring the position sensors 42 and 44 and sends signals to adjust the actuators of the actuator assemblies 60 and 62 to maintain the blade 4 at the desired angle of attack. During the removal process an experienced operator may find it desirable to use a different angle of attack. As such, the user interface may include the ability for such a user to send signals to the controller 40 causing the controller 40 to modify the angle of attack within some predefined range.

FIGS. 14 through 17 illustrate an alternative method of operation of machine 1. As illustrated in FIG. 14, controller 40 has four principal subroutines. These include a log-in subroutine 200 further illustrated in FIG. 15, a user set-up subroutine 220 further illustrated in FIG. 16, a machine setup subroutine 240 illustrated in FIG. 17, and a run subroutine 260 in which the operator operates controls to perform a floor stripping operation in accordance with the parameters set during subroutines 200, 220, and 240.

Prior to performing a stripping operation with the machine, touch display 8 (or some other input device) may be used to supply certain data to controller 40 to populate a table or database 210 stored in the storage (or memory) of controller 40. The database 210 typically will include data identifying each authorized user of the machine together with a username, password, and various operating parameters associated with each user. Such data may also include machine specific data. Without deviating from the invention, other reliable user authenticators (e.g., biometrics or key fobs) may be employed to identify users and whether they are authorized to operate the machine.

At power on, controller 40 asks for a username and password (or other authentication) and checks those entered against a stored database of authorized users. Failure by the user to enter such login information matching that of an authorized user will cause the machine to shut down. This feature offers several advantages. First, it serves to reduce the risk of an untrained or unauthorized user from operating the machine which could lead to property damage or injury. Second, it serves to reduce the risk of theft. Third, it can be used to create and store a log in the memory/storage of the controller 40. This log may include an identification of who was using the machine and when. If machine 1 also has a GPS receiver coupled to the controller 40, this log may also include the location where the machine was operated by the user. Other information related to the operation of the machine by the user may also be stored in this log for future reference. If the machine is equipped with a communications transceiver 41, this log, including without limitation the machine's location, can be transmitted to a remote location such as a communication center operated by the manufacturer or a rental company. Communications transceiver 41 may be a cellular transceiver, a Wi-Fi transceiver, a Bluetooth transceiver, or any other transceiver connected to the internet (or a cellular network) to transmit log and location information. Transceiver 41 can also be used by the machine to receive alerts, other messages, and even control signals from a remote location. Controller 40 can respond to such signals by causing alerts and other messages to be displayed, or to otherwise control one or more features of the machine. For example, the log may contain data reflecting hours of use since the hydraulic fluid of the machine was last changed, and the controller 40 in response to a preprogrammed set of instructions can send an alert to a display on the machine when the oil needs to be changed and/or send a corresponding message to a remote location. The machine location information may also be transmitted to a remote location. If it is determined that the machine is at an unauthorized location, a control signal can then be sent back to the machine from the remote location causing the controller 40 to disable operation of the machine. Similarly, the log can include information related to the type of blade and the hours of use of the blade. The controller can process this data and send signals to the display advising the operator to change the blade. Such log information can also be sent to a remote location and used to automate the timely ordering of replacement blade and other machine parts. Such transceivers 41 coupled to the controller 40 can certainly be used to transmit other information to or from the machine for various purposes without deviating from the invention.

In the embodiment illustrated, when a user wishes to operate the machine 1, the user must login by entering a username at step 201 on touch display 8. The controller checks the entered username against database 210 at step 202 to ensure an authorized username has been entered. If so, the user is prompted to provide and enter the user's password at step 204. At step 206, controller 40 compares the entered password with the user's password stored in database 210 to see if they match. If so, the program begins the user set-up subroutine 220. If the entered username is not authorized, step 203 is performed. If a predetermined maximum number of attempts at supplying an authorized username has not been exceeded, the program returns to step 202 and the user is again asked to enter the username. If the predetermining maximum number of attempts has been exhausted, the program moves to step 212, and the machine shuts down or for a predetermined period is locked. Likewise, if an authorized username has been entered, but the password entered at step 204 does not match the password of the user, step 205 is performed. If a predetermined maximum number of attempts at supplying an authorized user's password has not been exceeded, the program returns to step 204 and the user is again asked to enter the password. If the predetermining maximum number of attempts has been exhausted, the program moves to step 212, during which the machine shuts down and for a predetermined period is locked.

In the user set-up routine 220, a user may set or modify user specific operating parameters associated with that user using the user interface. As shown in FIG. 16, such user specific operating parameters may include the maximum speed at which the machine will operate, the maximum rate at which the machine will accelerate, the sensitivity of one or more controls such as the sensitivity of joystick 7 used during the run subroutine to control the speed and direction of the machine's movement across a floor or other surface. These user specific parameters are exemplary, and others may be added or eliminated without deviating from the invention. Some of these parameters may be preset and some users may not be authorized to modify such parameters. For example, if the machine is owned by a rental company and used by a renter, the rental company may set parameters related to maximum speed or maximum rate of acceleration which the renter's login credentials will not allow the renter to alter.

When performing the user setup subroutine, the controller 40 causes the touch display 8 to display the user specific operating parameters that may be altered by the user and the current setting for each as a representation of a slider. The user can use touch display 8 to adjust these sliders and thereby separately modify each such parameter. For example, at step 222, the user may slide the maximum speed sider to the left to lower the maximum speed at which the machine will roll across the floor under power, and to the right to increase the maximum speed at which the machine will roll across the floor under power. Similarly, at step 224, the user can slide the acceleration sider to the left to lower the rate at which the machine will accelerate under power, and to the right to increase rate at which the machine will accelerate under power. For machines equipped with a transceiver, the specific operating parameters may be set from a remote location or using an application on the user's cell phone or the like which serves as the user interface or a portion thereof. At step 226, the sensitivity of the various controls may be set or adjusted.

The machine may also have additional controls for additional features that may be individually enabled and disabled at step 228. For example, the touch screen 8 may display a list of such additional controls together with an enable/disable button or check box associated with each. A user can actuate the button or check/uncheck the check box to enable or disable each such additional control at step 228. The sensitivity of any controls that the user chooses to enable may be controlled at step 229. Specifically, a slider appears adjacent to each enabled control in the list and the user can move the slider to the left or the right to adjust the sensitivity of that control. Again, some users, based on their login credentials, may not be able to either enable, disable, or alter some of the otherwise available options.

In various embodiments, machine 1 will be equipped with a joystick 7 manipulated by the user when the machine is in the run mode 260 to send signals to the controller 40. The signals from the joystick 7 may be used to send signals to controller 40 which the controller 40 uses to control the speed of the machine in either the forward or rearward direction and steer the machine. The user can alter the state and the sensitivity of the joystick 7 beginning at step 230. First, the controller 40 checks to see if there is a joystick 7 and whether it is in the enabled or disabled state at step 232. At step 232, the user can select whether to enable or disable the joystick, again in an intuitive way, using touch screen 8. At step 233 the user can decide whether to adjust the sensitivity of the enabled joystick 7 in either a simple or an advanced way. If the user selects a simple manner of adjustment, only two sliders are displayed. At step 234 one such slider is used to adjust the sensitivity of all the axes of the joystick simultaneously and at step 235 another slider is used to adjust the null point for all such axes simultaneously. A more advanced user may wish to separately adjust each axis and the null point for each axis separately. If advanced adjustment is selected at step 233, a pair of sliders are separately displayed for each separate axis of the joystick, one of the pair is used to adjust the sensitivity of the joystick with respect to the corresponding axis and the other of the pair is used to adjust the null point for such corresponding axis. At step 236, the user moves the individual axis sliders separately to the left or to the right to decrease or increase the sensitivity of the joystick 7 with respect to the corresponding axis, and at step 237 the user moves the individual null point sliders for the axes to the left or right to decrease or increase the sensitivity of the corresponding null points.

Once all the user specific parameters have been set (or modified) and stored in database 210, the program proceeds to the machine setup subroutine 240. Here, the user (or sensor 49, if provided) can identify a flooring type to be removed at step 242. The user can do so using touch display 8, a multi-position selector switch 100, or a set of switches 101. At step 244, the controller 40 receives information related to the type of blade attached to machine 1. This information may be supplied to controller 40 by sensor 50 if provided or by a user via touch display 8, a multi-position selector switch 100, or a set of switches 101. Other machine specific parameters may also be provided to the controller 40 at step 246 using touch display 8, a selector switch, a set of switches, or set of sensors. Again, if the machine includes a transceiver, these parameters may be set remotely or using an application installed on the user's smart phone or the like.

As indicated above, such machines are typically provided with a set of removable weights. Such weights 27 are used to put pressure on the leading edge of the blade to keep the blade in firm contact with the floor and reduce any bouncing of the blade thereby increasing the efficiency with which floor coverings and adhesive materials are removed from the floor when using the machine 1. As shown in FIGS. 20 through 23, a group of auxiliary weights 27 are held in a cartridge 270. Projections 271 extend from the cartridge that mate with concave recesses on the machine to hold the cartridge 270 and the weights 27 contained therein in place. The cartridge 270 together with the weights 27 and be easily removed from the machine for separate transport or separate storage using a dolly 274. The total amount of weight within the cartridge 270 can be altered by adding and removing weights from the cartridge. The total weight of the cartridge and the weights contained therein can be determined using a scale or, when attached to the machine, sensor 47 of the machine. Sensor 47 of the machine (or a user via touch display 8, a multi-position selector switch 100, a set of switches 101, or a smart phone app) can supply to the controller 40 the number of auxiliary weights or the additional weight supplied by such auxiliary weights within the cartridge. When a smart phone app is employed, the app can use the camera on a smart phone to take a picture of the weights in the cartridge 270 and send the picture to the controller which the controller processes to identify the total weight supplied by the auxiliary weights.

Also, an experienced user may have login credentials that allow the user to enter an adjustment factor related to the blade's angle of attack, or may elect to disable the automatic blade positioning feature provided at steps 248 through 256 discussed below.

At step 248, the controller 40 uses any information supplied at steps 242, 244 and 246 to identify a recommended blade holder position, i.e., angle of attack. Controller 40 ascertains at step 252 the angle of the blade holder 24 relative to the vertical plate 22 using signals from sensor 44 and adjusts the angle at step 252 by modulating the position of the actuator or actuator assembly 60. Controller 40 also determines the height of the vertically adjustable plate 22 at step 254 using signals from sensor 42 and adjusts the height of the vertical plate 22 by modulating the position of the actuator of actuator assembly 62 at step 256. Steps 250 and 256 are repeated until the actual angle of attack of the blade matches the recommended angle of attack.

The program next enters run mode 260 and the user is then able to begin stripping the floor. While in the run mode, steps 250 through 256 are repeated periodically to ensure that the desired angle of attack is maintained during the scraping operation.

Again, dashed lines are used in FIGS. 14 through 17 to steps that may be bypassed in certain embodiments or at a user's option.

FIGS. 24 and 25 illustrate a significant advantage of employing blade position sensor(s) 44/46 in combination with a standard seven segment alpha-numeric display unit 300 or a graphical display unit 302. As one skilled in the art will appreciate, such display units typically include a display controller configurable to receive signals from one or more other devices and cause the display to provide information based on such signals. As illustrated in FIG. 24, the sensor 44 can send signals indicative of the angle of the blade holder (and blade) to the display 300 which, in real time, provides that information numerically to a user of the machine. In embodiments having both a blade holder and a vertically adjustable plate, position sensors 44 and 46 may be employed such that these sensors either send signals to a single display 300 which is configured to display both the angle of the blade holder and the height of the vertically adjustable plate, or to two separate displays like 300, one displaying in real time the angle of the blade holder and blade, and another displaying in real time the height of the vertically adjustable plate. The display(s) then provide the position information related to both the vertically adjustable plate and the blade holder to the user. Such a display may also be coupled to the sensor 43 associated with the caster wheels 13 at the front of the machine to signal whether the casters are in contact with the floor.

FIG. 25 illustrates an embodiment having a display 302 providing information in both a graphical and numeric fashion. Display 302 includes a first three digit-seven segment display 304 configured to display in real time the angle of the blade holder/blade based on signals received from sensor 42 and a second three digit-seven segment display 306 configured to display in real time the height of the vertically adjustable blade plate based on signals received from sensor 44. Display 302 includes a third three digit-seven segment display 306 configured to display in real time the position of the caster wheels 13 based on signals received from sensor 43. In some embodiments, this three digit-seven segment display 307 may be replaced by a simple indicator light or even an audible buzzer or speaker. As shown, display 302 also includes a first plurality of LEDs 308 arranged in an arc used to display in real time a scale equating an angle of the blade/blade holder relative to the vertically adjustable plate based on the signals received from sensor 42. One or more LEDs of this first plurality of LEDs 308 are illuminated to provide an indication of this angle. Display 302 also includes a second plurality of LEDs 310 arranged vertically in a row. One or more LEDs of this second plurality of LEDs 308 are illuminated to provide an indication in real time of the height of the vertically adjustable blade plate. Alternatively, the LED display may include a single set of multi-colored LEDs. One color generated by the illuminated LEDs of the set is used to indicate the position of the vertically adjustable blade plate while a second color generated by the illuminated LEDs of the set is used to indicate the angle of the blade holder/blade relative to the vertically adjustable plate. In embodiments including only one actuator and only one position sensor, one of the three digit-seven segment displays and one of the two pluralities of LEDs may be eliminated, or alternatively be used to signal the position of the front casters relative to the floor. A separate display, such as an indicator light, or an audible alarm may be used to signal when the caster is in contact with the floor,

FIG. 26 shows a display 9 likewise able to display data received from the position sensors 42, 43 and 44. In this embodiment, switch 120 may be used to instruct the controller 40 to store the then current position of the blade holder and/or the vertically adjustable plate. At a later point in time, after either or both of the blade holder and vertically adjustable plate have moved, a user can actuate switch 122 to instruct controller 40 to send control signals to the actuator(s) 60 and 62 to restore the blade holder and/or vertically adjustable plate to the stored position. This feature saves time when, for example, replacing the blade with a new blade. In such cases, the user can store the desired operating position of the blade by actuating switch 120, move the blade holder and/or vertically adjustable plate to a position more convenient for changing the blade, change the blade, and then actuate switch 122 so that the controller and actuator(s) 60/62 return the blade to the desired operating position automatically. Such information can also be displayed on the touch screen display described above.

The present invention may also be employed in connection with a walk behind scraper as illustrated in FIGS. 27 through 31. In the embodiments shown in these figures, the walk behind floor scraper 400 has a drive section 402 comprising wheels 404 and 406 individually driven by electric motors 405 and 407. Walk behind scraper 400 further comprises a blade positioning assembly 410 coupled to the drive section 402. As shown, the blade positioning assembly 410 comprises a rotatable blade holder 412 coupled to an eccentric assembly 414 driven by a third motor 416 which serves to oscillate the blade holder 412 and the blade (not shown) attached thereto. The blade positioning assembly also includes an output link 116 416 coupling the blade holder 412 to eccentric assembly 414 and a linear actuator 418. The linear actuator 418 and the output link 116 cooperate to adjust the angle of the blade holder 412 (and blade held by the blade holder) 412 and then hold the blade at a desired angle.

The walk behind scraper 400 also includes a pair of sliding weights 420 and 422 configured to slide along rails 421 and 423 between a stowed position near the handle 430 and a deployed position immediately adjacent the blade positioning assembly 410. Two auxiliary, removable weights 424 and 426 are also shown.

A user interface 432 is provided at the top of the handle 430. User interface includes controls for motors 405, 407 and 416, and for linear actuator 418. Motors 405, 407 and 416 may be servo motors incorporating sensors configured to send information related to the direction and speed at which the motor is spinning to either a controller 500 or directly to a display 480 of the user interface. Separate sensors may alternatively be used to send such signals. Similarly, the linear actuator 418 may include a built-in sensor, or a separate sensor may be used, to send signals to a controller 500 or a display of the user interface 432. Sensors may also be employed to determine whether the weights 424 and 426 are attached to the machine and the position of the sliding weights 420 and 422.

As shown in FIG. 30, the walk behind scraper includes eight sensors. These sensors include wheel sensors 460 and 462, and eccentric sensor 464. These are used to provide signals indicative of the speed of rotation of the wheels 404 and 406 and the eccentric of the eccentric assembly 414. FIG. 30 also shows position sensor 466 configured to send signals indicative of the position (angle) of the blade holder 412 and blade attached to the blade holder. Four sensors are also provided related to the weights. Sensors 470 and 472 are proximity sensors configured to send a signal indicative of the positions of the sliding weights 420 and 422. Sensors 474 and 476 send signals indicative of whether the weights 424 and 426 are attached to the walk behind scraper. In the embodiment shown in FIG. 30, the sensors identified in the previous paragraph send signals to display array 480. More specifically, the speed of rotation of wheel 404 is numerically displayed on display 482 based on signals received from sensor 460, the speed of rotation of wheel 406 is displayed numerically on display 484 based on signals received from sensor 462, and the speed of rotation of the eccentric is displayed numerically on display 486 based on signals received from sensor 464. The angle of the blade holder is displayed numerically on display 488 based on signals received from sensor 466. Indicator lamps 490, 492, 494, and 496 are configured to illuminate based on signals received from sensors 470, 472, 474 and 476, respectively, to indicate to the user the status of the sliding weights 420 and 422, and auxiliary weights 424 and 426. The speed of any of three motors can be graphically represented on display 498 and the angle of the blade holder can be graphically represented on display 499.

As discussed above, control may be automated or regulated by providing a controller adapted to receive and process input signals received from the user interface and the sensors. As shown in FIG. 31, a controller 500 is provided that not only receives input signals from the sensors 460, 462, 464, 466, 470, 472, 474 and 476, but also receives user inputs provided by a plurality of user input devices 502, 504, 506, and 508. These user input devices may be of any of the types discussed above, e.g., selector switches, toggle switches, a joystick, etc. Input device 502 may be used to send signals to the controller 500 indicative of the type of blade attached or the type of flooring to be removed. Input 504 may be used to send signals to the controller 500 directing the controller to store, and later restore to a stored position, the angle of the blade. Input 506 may be used to instruct the controller regarding what information to display on display 498. Input device 508, for example if it is a joystick, may be used to send signals to the controller 500 indicative of a user's desired speed and direction for the walk behind floor scraper which the controller 500 processes to generate and send output signals to the wheel motors. As should be clear from the foregoing, the user input devices may vary in type and vary in the nature of the signals they send to the controller. Further, the number and type of sensors, the number and type of displays and the information displayed, and aspects controlled may all vary without deviating from the invention.

Within the scope of the following claims, the invention may be practiced otherwise than as specifically shown in the drawings, and described above. The foregoing description is intended to explain the various features and advantages, but is not intended to be limiting. The scope of the invention is defined by the following claims which are also intended to cover a reasonable range of equivalents.