ACTUATING ASSEMBLY FOR A HOLD DOWN ARRANGEMENT OF A CAN BODYMAKER REDRAW ASSEMBLY

Description

FIELD OF THE INVENTION

The disclosed concept relates generally to redraw assemblies for can bodymakers and, more particularly, to actuating assemblies for actuating hold down arrangements of redraw assemblies of can bodymakers. The disclosed concept further relates to bodymakers including redraw assemblies having such actuating assemblies.

BACKGROUND OF THE INVENTION

Generally, a can begins as a disk of metal, such as, but not limited to aluminum, also known as a “blank,” that is punched from a sheet or coil of metal. The blank is fed into a cupper. The cupper performs a blank and draw process to create a cup. That is, the blank is formed into a cup having a bottom and a depending sidewall. The cup is fed into a bodymaker, which performs a redraw and ironing operation. More specifically, the cup is disposed in a can forming machine (i.e., a can bodymaker) at the mouth of a die pack having substantially circular openings therein. The cup is held in place by a redraw sleeve which is part of a hold down arrangement/assembly. The redraw sleeve is a hollow tubular construct that is disposed inside the cup and biases the cup against the die pack. The redraw sleeve is carried by a carriage assembly of the hold down arrangement that moves in a reciprocating fashion between a forward positioning wherein the redraw sleeve biases a cup against the redraw die, and a retracted positioning wherein the redraw sleeve is spaced from the redraw die allowing for the next cup to be positioned adjacent the redraw die. The first die in the die pack is the redraw die, which is also a part of the redraw assembly. Other dies, the ironing dies, are disposed behind, and axially aligned with, the redraw die. The ironing dies are not part of the redraw assembly. An elongated, cylindrical ram having a punch at the forward, distal end is aligned with, and structured to travel through, the openings in the redraw die and the ironing dies. At the end of the die pack opposite the ram is a domer. The domer is a die structured to form a concave dome in the bottom of the cup/can.

Thus, during the drawing and ironing process a cup is disposed at one end of the die pack. The cup, typically, has a greater diameter than a finished can as well as a greater wall thickness. The redraw sleeve is disposed inside of the cup by the carriage assembly of the hold down assembly and biases the cup bottom against the redraw die. The opening in the redraw die has a diameter that is smaller than the cup. The ram, with the punch as the forward, distal end, passes through the hollow redraw sleeve and contacts the bottom of the cup. As the ram continues to move forward, the cup is moved through the redraw die. As the opening in the redraw die is smaller than the original diameter of the cup, the cup is deformed and becomes elongated with a smaller diameter. The wall thickness of the cup typically remains the same as the cup passes through the redraw die. As the ram continues to move forward, the elongated cup passes through a number of ironing dies. The ironing dies each thin the wall thickness of the cup causing the cup to elongate. The final forming of the can body occurs when the bottom of the elongated cup engages the domer, creating a concave dome in the cup bottom. At this point, and compared to the original shape of the cup, the can body is elongated, has a thinner wall, and a domed bottom. The can body is ejected from the ram, and more specifically the punch, for further processing, such as, but not limited to trimming, washing, printing, flanging, inspection and placement on pallets, which are shipped to the filler. At the filler, the cans are taken off of the pallets, filled, ends are placed (i.e., seamed) onto them, and then the filled cans are repackaged.

Conventional redraw assemblies provide for little to no diagnostic information for evaluating the health of components thereof such that maintenance can be carried out prior to failures and/or other events which will take a bodymaker offline for significant periods of time. Hence, there is room for improvement in redraw assemblies for bodymakers and components, such as hold down arrangements, thereof.

SUMMARY OF THE INVENTION

Embodiments of the disclosed concept improve upon existing solutions by providing arrangements which provide for real time monitoring and diagnostic information pertinent to operation of a hold down arrangement of a redraw assembly of a can bodymaker. From such monitoring/diagnostic information determinations about characteristics of components of the redraw assembly can be made and utilized for maintenance purposes and to prevent potentially catastrophic failures of the bodymaker.

As one aspect of the disclosed concept an actuating assembly for a hold down arrangement of a can bodymaker is provided. The actuating assembly comprises: a cam body structured to be rotatably coupled to a frame of the bodymaker so as to be rotatable about a rotation axis by an operating mechanism, the cam body having a cam surface defining a cam path; a swing lever comprising: a main portion having a first end and a second end opposite the first end, the first end structured to be pivotably coupled to the frame of the bodymaker and the second end structured to be operatively coupled to a redraw assembly of the hold down arrangement; and a hub portion positioned intermediate the first end and the second end of the main portion, the hub portion engaged with the cam surface of the cam body so as to follow the cam path as the cam body rotates about the rotation axis; and a sensing arrangement including a controller and a number of sensors in communication with the controller, wherein one or more of a portion of the cam body bounded by the cam surface and/or a number of portions of the swing lever are structured to deform in a predetermined manner responsive to the engagement of the hub portion and the surface of the cam body, and wherein the controller is structured to determine a force within the actuating assembly from a number of sensed deformations of one or more of the portion of the cam body and/or the number of portions of the swing lever.

The controller may be structured to determine a force within the actuating assembly from the number of sensed deformations of at least two of the portion of the cam body and/or the number of portions of the swing lever.

The controller may be structured to determine a force within the actuating assembly from the number of sensed deformations of each of the portion of the cam body and the number of portions of the swing lever.

The hub portion may be separate from the main portion and coupled to the first end of the main portion by a first arm member and to the second end of the main portion by a second arm member. The number of portions of the swing lever may comprise one or both of a portion of the first arm member and/or a portion of the second arm member. The number of sensors may comprise a sensor disposed on one of the first arm member or the second arm member. The number of sensors may comprise a sensor disposed on each of the first arm member and the second arm member. The sensor disposed on the one of the first arm member or the second arm member may comprise a strain gage. The sensor disposed on the first arm member may comprise a strain gage and the sensor disposed on the second arm member may comprise another strain gage.

The hub portion may comprise a roller follower rotatably coupled to the main portion via a pin member, and wherein the roller follower is engaged with the cam surface.

The cam body may comprise a pocket defined therein, and the portion of the cam body bounded by the cam surface may be disposed between the pocket and the portion of the cam surface. The number of sensors may comprise a sensor disposed at least partially within the pocket. The sensor disposed at least partially within the pocket may comprise a strain gage coupled to the portion of the cam body.

The actuating arrangement may further comprise a biasing arrangement positioned and structured to bias the hub portion of the swing lever against the cam surface. The biasing arrangement may comprise an airbag.

As another aspect of the disclosed concept a method for monitoring wear of one or more components of a hold down arrangement of a can bodymaker is provided. The hold down arrangement includes an actuating assembly such as previously described. The method comprises: monitoring, while the hold down arrangement is operating, deformation of one or more of the portion of the cam body and/or the number of portions of the swing lever; determining that the deformation of the one or more of the portion of the cam body and/or the number of portions of the swing lever has varied from a predetermined value or values; and providing an indication that the deformation of the one or more of the portion of the cam body and/or the number of portions of the swing lever has varied from the predetermined value or values.

Determining that the number of deformations of the one or more of the portion of the cam body and/or the number of portions of the swing lever has varied from a predetermined value or values may comprise determining that the number of deformations of at least two of the portion of the cam body and/or the number of portions of the swing lever has varied from the predetermined value or values.

Determining that the number of deformations of the one or more of the portion of the cam body and/or the number of portions of the swing lever has varied from a predetermined value or values may comprise determining that the number of deformations of each of the portion of the cam body and the number of portions of the swing lever has varied from the predetermined value or values.

These and other objects, features, and characteristics of the disclosed concept, as well as the methods of operation and functions of the related elements of structure and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the disclosed concept.

BRIEF DESCRIPTION OF THE DRAWINGS:

A full understanding of the disclosed concept can be gained from the following description of the preferred embodiments when read in conjunction with the accompanying drawings in which:

FIG. 1 is a partially schematic, side elevation view of a bodymaker;

FIG. 2 is a partially schematic, perspective view of a hold down arrangement in accordance with an example embodiment of the disclosed concept;

FIG. 3 is a partially exploded perspective view of the actuating assembly of the hold down arrangement of FIG. 2;

FIG. 4 is a side elevation view of the actuating assembly of FIGS. 2 and 3 showing a cam body thereof disposed in a first rotational positioning;

FIG. 5 is a side elevation view of the actuating assembly of FIGS. 2 and 3 similar to FIG. 4 but with selected elements shown in sectional view to show internal details thereof;

FIG. 6 is a detail view of the portion of the view of FIG. 5 indicated therein;

FIG. 7 is a side elevation view of the actuating assembly of FIGS. 2-4 showing the cam body thereof in a second rotational positioning different than the first rotational positioning shown in FIG. 4; and

FIG. 8 is a detail view of the portion of the view of FIG. 7 indicated therein.

DETAILED DESCRIPTION OF THE INVENTION

The specific elements illustrated in the drawings and described herein are simply exemplary embodiments of the disclosed concept. Accordingly, specific dimensions, orientations and other physical characteristics related to the embodiments disclosed herein are not to be considered limiting on the scope of the disclosed concept.

As employed herein, the term “can” refers to any known or suitable container, which is structured to contain a substance (e.g., without limitation, liquid; food; any other suitable substance), and expressly includes, but is not limited to, beverage cans, such as beer and soda cans, as well as cans used for food.

As used herein, “coupled” means a link between two or more elements, whether direct or indirect, so long as a link occurs. An object resting on another object held in place only by gravity is not “coupled” to the lower object unless the upper object is otherwise maintained substantially in place. That is, for example, a book on a table is not coupled thereto, but a book glued to a table is coupled thereto.

As used herein, “directly coupled” means that two elements are coupled in direct contact with each other.

As used herein, “fixedly coupled” or “fixed” means that two components are coupled so as to move as one while maintaining a constant orientation relative to each other. The fixed components may, or may not, be directly coupled.

As used herein, the word “unitary” means a component is created as a single piece or unit. That is, a component that includes pieces that are created separately and then coupled together as a unit is not a “unitary” component or body.

As used herein, “engage,” when used in reference to gears or other components having teeth, means that the teeth of the gears interface with each other and the rotation of one gear causes the other gear to rotate as well.

As employed herein, the term “number” shall mean one or an integer greater than one (i.e., a plurality).

As used herein, the term “controller” shall mean a programmable analog and/or digital device (including an associated memory part or portion) that can store, retrieve, execute and process data (e.g., software routines and/or information used by such routines), including, without limitation, a field programmable gate array (FPGA), a complex programmable logic device (CPLD), a programmable system on a chip (PSOC), an application specific integrated circuit (ASIC), a microprocessor, a microcontroller, a programmable logic controller, or any other suitable processing device or apparatus. The memory portion can be any one or more of a variety of types of internal and/or external storage media such as, without limitation, RAM, ROM, EPROM(s), EEPROM(s), FLASH, and the like that provide a storage register, i.e., a non-transitory machine readable medium, for data and program code storage such as in the fashion of an internal storage area of a computer, and can be volatile memory or nonvolatile memory.

FIG. 1 is a side elevation, partially schematic view of a can bodymaker 10 (such as described in U.S. Patent Application Pub. No. 2021/0229155, the contents of which are incorporated by reference herein) that is structured to convert a cup 2 into a can body 3. The cup 2 is assumed to be substantially circular. It is understood, however, that the cup 2, as well as the resulting can body 3 and elements that interact with the cup 2 or can body 3, may have a shape other than substantially circular. A cup 2 has a bottom member with a depending sidewall defining a substantially enclosed space (none shown). The end of the cup 2 opposite the bottom is open. The can bodymaker 10 includes a reciprocating ram 12, a drive mechanism 14, a toolpack 16, a redraw assembly 18 and a cup feeder 20 (shown schematically). That is, the drive mechanism 14 is coupled to the ram 12 (which is slidably coupled to a frame, formed from a number of elements, shown generally as 15, of the bodymaker 10) and structured to impart a reciprocating motion to the ram 12. As is known, in each cycle the cup feeder 20 positions a cup 2 in front of the toolpack 16 with the open end facing the ram 12. When the cup 2 is in position in front of the toolpack 16, a redraw sleeve assembly 40, biases the cup 2 against a redraw die 42. The ram 12 has an elongated, substantially circular ram body 30 with a proximal end 32, a distal end 34, and a longitudinal axis 36. The distal end 34 of the ram body 30 includes a punch 38. The proximal end 32 of the ram body 30 is coupled to the drive mechanism 14. The drive mechanism 14 provides a reciprocal motion to the ram body 30 causing the ram body 30 to move back and forth along its longitudinal axis 36. That is, the ram body 30 is structured to reciprocate between a first, retracted position and a second, extended position. In the first, retracted position, the ram body 30 is spaced from the toolpack 16. In the second, extended position, the ram body 30 extends through the toolpack 16. Thus, the reciprocating ram 12 advances forward (to the left as shown) passing through the redraw sleeve assembly 40 and engaging the cup 2. The cup 2 is moved through the redraw die 42 and a number of ironing dies (not shown) within the toolpack 16. The cup 2 is converted into a can body 3 within the toolpack 16 and then removed therefrom. It is understood that, as used herein, a “cycle” means the cycle of the ram 12 which begins and ends with the ram 12 in the first, retracted position.

Generally, the redraw assembly 18 includes the movable redraw sleeve assembly 40 and the redraw die 42. The redraw die 42 is disposed within the toolpack 16 adjacent the redraw sleeve assembly 40. That is, the redraw die 42 is the first die in the toolpack 16. Meanwhile, the redraw sleeve assembly 40 moves, in a reciprocating manner, toward the redraw die 42 to clamp a cup 2 against the redraw die 42 for a predetermined time, and away from the redraw die 42 to allow for a new cup 2 to be positioned by the cup feeder 20, and then back toward the redraw die 42 to clamp the new cup 2 into position against the redraw die 42. U.S. Patent Application Pub. No. 2021/0229155, commonly assigned with the present application, further describes a number of improvements to such general arrangement.

As briefly discussed in the Summary of the Invention above, embodiments of the disclosed concept provide diagnostic and monitoring information pertinent to the primary functional mechanism of beverage container bodymaking machines. More specifically, embodiments of the disclosed concept provide arrangements to evaluate the health of components of a bodymaker such as, for example, without limitation, the hold down carriage, hold down actuating assembly, front hold down piston assembly, rear hold down assembly and the front/rear hold down air bags, by determining and monitoring the forces encountered while driving the mechanism during normal operation of the bodymaker. Such information regarding the mechanism can be utilized for maintenance purposes and to prevent potentially catastrophic failures.

Referring now to FIG. 2, a hold down arrangement 100 in accordance with an example embodiment of the disclosed concept such as may be employed and/or readily adapted for use with conventional can bodymakers (e.g., without limitation, such as shown in FIG. 1 and those described in the aforementioned U.S. Patent Application Pub. No. 2021/0229155) is shown, and will be described, where appropriate, with reference to elements of bodymaker 10 of FIG. 1. The hold down arrangement 100 includes a redraw assembly 102 and an actuating assembly 104 operatively coupled to the redraw assembly 102. The redraw assembly 102 includes a redraw sleeve assembly 106 (having a redraw sleeve, not numbered) that is structured to be positioned, and translate along the longitudinal axis 36 of the ram 12 (such as of bodymaker 10), and to engage and bias a cup 2 against a redraw die of a toolpack (such as previously discussed). The redraw assembly 102 further includes a hold down carriage 108 which carries/supports the redraw sleeve assembly 106. The hold down carriage 108 is fixedly coupled with a pair of pushrods 110 which extend from the hold down carriage 108 in a direction opposite the redraw sleeve assembly 106 and which are structured to be slidably coupled (e.g., via linear bearing arrangements 111) to the frame 15 (shown schematically) of the bodymaker 10.

Continuing to refer to FIG. 2, and additionally to FIGS. 3-8, the actuating assembly 104 includes a cam body 112 fixedly coupled about a shaft 113 that is structured to be rotatably coupled to the frame 15 of the bodymaker 10 so as to be rotatable (as shown by the arrow R) about a rotation axis 114 by an operating mechanism 116 (shown schematically in FIG. 2). The cam body 112 includes a cam surface 118 which defines a cam path. The actuating assembly 104 further includes a swing lever 120 of a generally elongate shape and including a main portion 122 having a first end 124 and a second end 126 opposite the first end 124. The first end 124 of the main portion 122 is structured to be pivotably coupled (e.g., via a pin 125, FIGS. 4, 5, and 7) to the frame 15 of the bodymaker 10. The second end 126 of the main portion 122 is structured to be operatively coupled (e.g., via a pin 127 and connecting rod 128) to the redraw assembly 102 of the hold down arrangement 100, and more particularly to a corresponding pushrod 110 extending from the hold down carriage 108 previously discussed. The swing lever 120 further includes a hub portion 130 positioned intermediate the first end 124 and the second end 126 of the main portion 122 that is sized and configured to engage, and follow, the outer surface 118 of the cam body 112 as the cam body 112 is rotated about the rotation axis 114 by the operating mechanism 116. In the illustrated example, the hub portion 130 includes cam follower 132 (FIGS. 4 and 5) positioned in a pocket 134 (FIG. 5) defined in the main portion 122 of the swing lever 120 about a follower pin 136 having a longitudinal axis 138 about which the cam follower 132 may freely rotate (e.g., via a suitable bearing or other arrangement). In such example arrangement, the follower pin 136, and thus the hub portion 130, is coupled to the first end 124 of the main portion 122 of the swing lever 120 by a first arm member 140 and to the second end 126 of the main portion 122 of the swing lever 120 by a second arm member 142. In such arrangement, each of the first arm member 140 and the second arm member 142 are structured to deform in a predetermined manner as discussed further below responsive to forces resulting from the interaction between the hub portion 130 and the cam surface 118 during operation of the hold down arrangement 100.

A biasing arrangement 144, provided as a portion of the actuating assembly 104, provides a biasing force F (FIG. 4) which serves to bias the hub portion 130 of the swing lever 120 against the cam surface 118 of the cam body 112 as the cam body 112 is rotated about the rotation axis 114 by the operating mechanism 116 during can body forming operations of the can bodymaker 10. In the example hold down arrangement 100 illustrated, the biasing arrangement 144 is an adjustable air bag arrangement coupled to the hub portion 130 via a clevis 146 engaged with either end of the follower pin 136 wherein the biasing force F exerted thereby may be adjusted and/or monitored by controlling/monitoring the air pressure in a number of air bags 148 (FIG. 5) thereof.

From the perspective views shown in FIGS. 2 and 3, it is to be readily appreciated that the example actuating assembly 104 generally includes a second arrangement of the components thereof previously described herein, which function the same as the first arrangement discussed and thus are not discussed in any further detail herein. In operation, rotation of the cam body(bodies) 112 (i.e., via rotation of shaft 113) causes the second end(s) 126 of the main portion(s) 122 of the swing lever(s) 120 to move in a reciprocating manner (such as shown by double ended arrow RM of FIG. 4) as the hub portion(s) 130 follow(s) the varying cam surface(s) 118 of the cam body (bodies) 112, thus moving the hold down carriage 108 and the redraw sleeve assembly 106 carried thereon to move in a reciprocating manner, similar to the conventional arrangements previously discussed herein.

In order to provide diagnostic and monitoring information regarding the hold down arrangement 100 during can body making operations as previously mentioned, the actuating assembly 104 further includes a sensing arrangement 150 (FIGS. 4-8) that is structured to detect deformation(s) of one or more portions of the actuating assembly 104 responsive to the engagement of the hub portion 130 and the cam surface 118 of the cam body 112 and use such detection(s) to determine and provide information regarding the hold down arrangement 100 and/or components thereof to other devices and/or person(s). In the example arrangement illustrated in FIGS. 2-8, deformations of one or more of: a portion 152 of the cam body 112 bounded by a portion 154 of the cam surface 118 (such as shown/described below in conjunction with FIGS. 4-8 below), a portion (not numbered) of the first arm member 140, and/or a portion (not numbered) of the second arm member 142 may be detected and analyzed by sensing arrangement 150 as discussed below.

Referring to FIGS. 4-8, the example cam body 112 includes two portions 152 thereof, each bounded by the corresponding portion 154 of the cam surface 118, that are structured to selectively elastically deform in a predetermined manner responsive to forces applied thereto via the hub portion 130. FIG. 7 and the detail view of the portion thereof shown in FIG. 8 show an exaggerated illustration of such deformation of a selected portion 152 of the cam body 112 responsive to engagement of the corresponding portion 154 of the cam surface 118 with cam follower 132 in accordance with one example loading in accordance with an example embodiment of the disclosed concept. It is to be appreciated that the placement and/or quantity of such portion(s) 152 of the cam body 112 selected to selectively deform may be varied without varying from the scope of the disclosed concept. For example, without limitation, locations wherein the cam surface 118 undergoes high rates of change (thus causing more rapid movement of the swing arm 120) have been employed in some example embodiments of the disclosed concept. To provide for such selective deformation of each portion 154, the cam body 112 further includes a pocket 156 defined therein. The amount of deformation of each portion 154, and thus the strain induced therein by the interaction with hub portion 130 depends both on the force required to drive the redraw assembly 102 and also the thickness t of the portion 154. If the supporting material adjacent to the cam surface 118 is thinned to a certain degree, then the force from the hub portion 130 will induce a certain amount of deformation/strain into the supporting material (i.e., portion 154). By choosing the thickness t (FIGS. 6 and 8) of the supporting material, the expected strain induced by the hub portion 130 can be placed within the measurement range of commonly available strain gauges, thereby, giving a relative measurement of the force required to actuate the redraw assembly 102 and any elements in the arrangement prior thereto.

In addition to, or instead of, monitoring deformation of portions 152 of the cam body 112, one or more portions of the swing arm 120 may be monitored. For example, without limitation, in the example embodiment shown in FIGS. 4-8, each of the first arm member 140 and the second arm member 142 is structured to deform in a predetermined manner from engagement between the hub portion 130 and the cam surface 118. FIG. 7 shows an exaggerated illustration of such deformation of the first arm member 140 (or a portion thereof) and second arm member 142 (or a portion thereof) responsive to engagement of the cam surface 118 with cam follower 132 in accordance with one example loading in accordance with an example embodiment of the disclosed concept.

To monitor such deformation of one or more of: the portion(s) 154 of the cam body 112, the portion of the first arm member 140 and/or the portion of the second arm member 142, sensing arrangement 150 includes a number of sensors 160 and a monitoring arrangement/controller 162 (shown schematically in FIGS. 6 and 8) in communication (e.g., via any suitable wired or wireless arrangement) with each sensor 160 of the number of sensors 160. In the example shown in FIGS. 4-8, each sensor 160 is a strain gage and monitoring arrangement/controller 162 is a data acquisition/analysis system, however, it is to be appreciated that other suitable sensor(s) 160 and/or arrangements 162 may be employed without varying from the scope of the disclosed concept. By continually monitoring the deformation(s) of one or more of: portion(s) 154 of the cam body 112, the portion of the first arm member 140 and/or the portion of the second arm member 142, and thus the forces corresponding to such deformations with controller 162 during operation of the hold down arrangement 100, a baseline can be developed for how much force is required to actuate the hold down arrangement 100 in different machine operating regimes. Once this baseline is acquired, subsequent force data can be compared to the baseline to give an indication of the health of the arrangement or to assist with diagnostics. For example, if the relative force measurement(s) has(have) decreased suddenly, then perhaps some mechanical failure has occurred which could prompt the machine control algorithm of a machine controller to provide a warning to an operator or to enter an emergency shutdown. As yet another example, if the relative force measurement(s) has(have) increased gradually over a substantial amount of time, then perhaps bearings (e.g., linear bearing arrangement(s) 111), hub portion 130, connections at one of pins 125 or 127, or some other location(s) within the hold down arrangement 100 are due for maintenance and thus an appropriate indication or indications can be provided to a control panel of the machine or to a remote notification system (or other appropriate arrangement(s)).

From the foregoing it is to be appreciated that embodiments of the disclosed concept provide diagnostic and monitoring information pertinent to the primary functional mechanism of machines used in manufacturing can bodies, such as the hold down arrangement of a can bodymaker. In such machines, embodiments of the disclosed concept can be employed to provide health estimates of components driven by the arrangement, such as, without limitation, the hold down carriage, hold down actuating assembly, front hold down piston assembly, rear hold down assembly and the front/rear hold down air bags, by determining and monitoring the forces encountered while driving the mechanism during normal operation of the bodymaker. By providing improved monitoring/estimations of health, maintenance can be better optimized and failures and downtime can be reduced.

While specific embodiments of the disclosed concept have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of disclosed concept which is to be given the full breadth of the claims appended and any and all equivalents thereof.

In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word “comprising” or “including” does not exclude the presence of elements or steps other than those listed in a claim. In a device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The word “a” or “an” preceding an element does not exclude the presence of a plurality of such elements. In any device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain elements are recited in mutually different dependent claims does not indicate that these elements cannot be used in combination.