Screed Plate for Paving Machine

Description

TECHNICAL FIELD

This patent disclosure relates generally to mobile paving machines for conducting a paving operation and, more particularly, to a floating screed assembly for compacting and texturing the paving material to produce a paving mat.

BACKGROUND

Mobile paving machines, referred to as road pavers, are used during a paving operation to apply, spread, and compact paving material into a paving mat over the ground or road bed to produce a smooth, hard surface such as a roadway, parking lot, or other paved area for cars, trucks, and other vehicles to travel upon. A typical example of paving material to produce a paved surface is a hot asphalt mix of hard aggregates like rocks, finer materials like sand, and a bitumen mixer or binder, and possibly other additives and modifiers. The paving material is initially in a loose, almost fluid, state to facilitate spreading and distribution over the work surface and to cover the desired areas.

To distribute the paving material, the mobile paver may be operatively associated with a screed assembly that is attached to and towed along the travel direction of the paver. The screed assembly includes one or more flat metal screed plates attached to the underside of a screed frame. The mobile paver delivers the paving material to the work surface in front of the forward leading edge of the screed plate, which is moved over the distributed material by the forward travel of the mobile paver. The floating screed assembly may be self-leveling and attached to the mobile paver to freely float over the distributed paving material, and the weight of the screed assembly and the flatness of the screed plates spreads and compacts the paving material to form a paving mat. In possible variations, the screed assembly may be configured to vibrate to improve compaction of the paving material and the screed plate can be heated to prevent the paving material from adhering thereto.

Compaction of the paving material underneath the screed assembly increases the density of the produced paving mat to improve its durability to withstand vehicular travel and variable weather conditions. Typically, the paving mat will be subjected to further paving operations to improve its physical condition and operative characteristics. For example, one or more mobile compactors may follow the paving machine to further compact the paving material and increase the density of the paving mat. Additional machines can also be employed subsequently to impart other physical characteristics and properties to the paved surface, such as surface texturing and curing treatments to produce a more durable and functional paved surface. One example may be a grinding or grooving machine that subsequently cuts or mills grooves into the paved surface using diamond bits to increase surface friction and vehicular traction.

SUMMARY

The disclosure describes, in one aspect, a screed plate for a screed assembly towed by a mobile paver including a forward leading edge and a rearward trailing edge parallel to the forward leading edge. The screed plate also includes an upper frame attachment surface extending between the forward leading edge and the rearward trailing edge and a lower material contacting surface adapted to compact and compress paving material sliding underneath the screed plate. A texturing structure may be situated laterally along the rearward trailing edge to form a texturing pattern in a paving mat produced by the screed plate by displacement of the paving material.

In another aspect, the disclosure describes a method of laying and surface texturing a paving mat that includes receiving a paving material in a hopper of a mobile paver traveling longitudinally in a travel direction over a work surface. The method also includes conveying the paving material from the hopper to an auger arranged laterally and perpendicular to the travel direction of the mobile paver and laterally distributing the paving material before a screed frame of the floating screed. The paving material is directed underneath a forward leading edge of a screed plate attached to an underside of the screed frame and is compacted into a paving mat by sliding contact with a lower material contacting surface of the screed plate. The method also involves surface texturing the paving mat with a texturing structure situated laterally along the rearward trailing edge to produce a tining pattern in the paving mat.

In yet another aspect, the disclosure describes a floating screed assembly including a screed frame adapted to be towed behind a mobile paver and a screed plate releaseably attached to the screed frame. The screed plate has a forward leading edge and a rearward trailing edge parallel to the forward leading edge. The screed plate also has an upper attachment surface extending between the forward leading edge and the rearward trailing edge and a lower material contacting surface opposite the upper attachment surface adapted to compress paving material. A texturing structure may be situated laterally along the rearward trailing edge to form a texturing pattern in a paving mat produced by the screed plate by displacement of the paving material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of a mobile paver with a screed assembly moving in a travel direction to produce a homogenous paving mat over a work surface.

FIG. 2 is a forward perspective view of a screed assembly configured with screed extenders laterally extended from the screed frame and a plurality of textured screed plates attached to the underside of the screed frame.

FIG. 3 is a perspective view of the material contacting underside of a screed plate having a texturing structure configured to impart surface texturing to the paving mat in accordance with the disclosure.

FIG. 4 is a perspective view of the material contacting underside of another embodiment of the screed plate having a texturing profile configured to impart surface texturing to the paving mat in accordance with the disclosure.

FIG. 5 is a perspective view of the material contacting underside of a screed plate having a texturing rake with a plurality of tines configured to impart surface texturing to the paving mat in accordance with the disclosure.

FIG. 6 is a perspective view of the material underside of a textured screed plate having a textured surface to homogenously mix the paving material in cooperative association with a texturing structure to impart surface texturing to the paving mat.

DETAILED DESCRIPTION

Now referring to the drawings, wherein whenever possible like reference numbers will refer to like elements, there is illustrated in FIG. 1 an example of a mobile paving machine or paver 100 for laying down paving material 102 on the ground, roadbed, or another work surface 104 to produce a paving mat 106 that paves over and covers the work surface resulting in a paved surface. The finished paved surface may be intended as a roadway, highway, structural foundation or other surface having hardness, flatness and durability characteristics to sustain repeated vehicular traffic and endure changing weather conditions, including temperature changes and precipitation. To distribute the paving material 102 over the work surface 104, the mobile paver 100 can be self-propelled and operated to travel in a travel direction 108 that is aligned with the longitudinal axis or orientation of the paver. As used herein, the terms “forward” or “leading” may refer to the forward direction of the mobile paver 100 when traveling in the travel direction 108, and the terms “aft,” “rearward” or “trailing” may refer to the direction rearward of the mobile paver.

To accommodate and carry paving material 102 prior to distribution on the work surface 104, the mobile paver 100 can include a hopper 110 that is supported on a machine frame or chassis 112 that is the loadbearing structural support and framework of the paver. The hopper 110 can be an opened box-like structure or bin including upward extending sidewalls 114 that are laterally opposed and that contain the paving material 102 deposited therein. The hopper 110 can be located at the forward end of the mobile paver 100 and can receive paving material 102 from above via a transport vehicle such as a dump truck. As the paving material is distributed from the mobile paver 100, the hopper 110 can be regularly replenished with fresh paving material delivered from an asphalt plant or facility.

To direct the loose, granular paving material rearward from the hopper 110, the mobile paver 100 includes a conveyor system 116 that extends through and is supported by the chassis 112. The conveyor system 116 may include one or more conveyor belts that translate about rotating pulleys or drums to move the paving material 102 rearward and discharge the material from the mobile paver 100 to the work surface 104.

To propel the mobile paver 100 over the work surface 104 during a paving operation, the chassis 112 can be supported on a plurality of ground engaging elements 118 that direct and transfer traction and propulsion forces to the work surface 104. An example of the ground engaging element 118 can be continuous tracks that are looped as a belt around a plurality of drive sprockets that can rotate with respect to the chassis 112. The continuous tracks translate with respect to the chassis 112 to move the mobile paver 100 over the work surface 104. Another example of ground engaging elements 118 can be rotatable wheels journalled to the chassis 112.

To generate motive power and drive the ground engaging elements 118, the mobile paver 110 can include an engine 120 supported on the chassis 112. The engine 120 can be a conventional internal combustion engine that combusts a hydrocarbon-based fuel to convert the lateral chemical energy therein to motive power for propulsion and other work. The engine 120 can also be associated with a generator 122 to generate electricity for powering the electrical system of the mobile paver 100. In other possible configurations, the mobile paver 100 can include an electrical powertrain and can be operatively driven by a plurality of electrical storage batteries or fuel cells.

To accommodate an operator for steering and controlling the mobile paver 100, an operator station 124 or operator cab can be situated on top of the chassis 112 in a location providing visibility over the work surface 104. Located in the operator station 124 can be various controls and input control devices 126 such as a steering wheel to alter the travel direction 108 of the mobile paver 100, accelerator and brake pedals, gear and direction shifters, and the like. To visually interface with the operator, the operator station can include an instrument console 128 having various dials, readouts, display screens and the like. Moreover, the input control devices 126 and the instrument console 128 can be associated with an electronic controller configured or programmed to receive and process data and information to assist in operation of the mobile paver 100.

To more evenly distribute the paving material 104, a screed assembly 130 can be coupled to the rear end of the chassis 112 that can be moved over the deposited paving material 102 by the forward travel of the mobile paver 100 in the travel direction 108. The screed assembly 130 can be associated with an auger 132 located rearward and below the conveyor system 116 and arranged to direct and move the loose paving material 114 discharged therefrom laterally towards the sides of the chassis 112. The auger 132 is arranged in a lateral direction 134 or axis that is perpendicular to the forward and rearward travel directions 108 and at right angles to the longitudinal axis of the chassis 112. Moreover, the auger 132 is vertically adjacent to the work surface 104 and establishes a vertical direction 135 normal to both the travel direction 108 and the lateral direction 134. The auger 132 can be an elongated rotating structure with oppositely directed spiral or helical flights that push the paving material 104 laterally outward when rotated.

To compress and smooth the granular paving material 102 laterally distributed by the auger 132, the screed assembly 130 includes one or more screed plates 136 that are attached to the underside of a screed frame 138. The screed plates 136 are metal plates adapted to contact and slide over the paving material 102 deposited on the work surface 104, and the weight and load of the screed frame 138 compresses the loose paving material 102 into the denser, harder paving mat 106. By way of example, the material of the screed plates 136 can be cast nickel alloy, chromium alloy, or hardened steel.

To increase the compressive forces applied to the paving mat 106, the screed frame 138 can include internal eccentric weights that generate vibrating forces in the vertical direction 135 that vibrate the screed plates 136 contacting the paving material 102. To prevent the paving material 102 from cooling and adhering to the screed plates 136, the screed assembly 130 can be associated with inductive heaters located in the screed frame 138.

To adjust the thickness of the paving mat 106, the screed assembly 130 can be pivotally connected to the chassis 112 by one or more tow arms 140. The screed frame 138 can also be pivotally tilted with respect to the chassis 112 to adjust the angle of attack, or the angle that the screed plates 136 encounter and come into contact with the paving material 102 exiting the conveyor system 116 onto the work surface 104. Adjusting the angle of attach enables the screed plates 136 to move and slide over the paving material 102 allowing the screed assembly 130 to float with respect to the work surface 104. To raise and lower the screed assembly 130 in the vertical direction 135 to contact and disengage from the work surface 104, one or more extendable and retractable hydraulic lift cylinders 141 can also be connected between the chassis 112 and the screed frame 138.

Referring to FIG. 2, the screed assembly 130 can be extendable in the lateral direction 134 to adjust the lateral width of the screed frame 138. For example, the screed frame 138 can include a main screed section 142 and first and second extender screed sections 144 located toward the opposite lateral ends of the screed assembly 130. The extender screed sections 144 can be located behind the main screed section 142 and the structures can be slidingly connected together, for example, by a sliding dovetail rail. In another configuration, the extender screed sections 144 can be mounted toward the front of the screed frame 138 with respect to the travel direction 108.

The screed assembly 130 can also include hydraulically actuated extender cylinders 146 that operatively connect the main screed section 142 with the first and second extender screed sections 144. Actuation of the extender cylinders 146 moves the first and second extender screed sections 144 in the lateral direction 134 with respect to the main screed section 142. To retain the lateral distribution of the paving material 104, the first and second extender screed sections 144 can each include a lateral flange 148 or blades parallel to and aligned in the travel direction 108.

The screed plates 136 can be removably attached to the underside of main screed section 142 and the first and second extender screed sections 144. A plurality of screed plates 136 can extend across the lateral width of the screed frame 138 to produce a continuously smooth flat paving mat 106 across the lateral direction 134 and extending rearward of the screed assembly 130 in the travel direction 108.

The front of the screed frame 138 may also include a forward panel that extends upward from the intersection with the screed plates 136 that may be configured as a solid planar panel extending in the lateral direction 134. The front of the screed frame 138 pushes excess paving material 102 discharged from the conveyor system forward in the travel direction 108 until the material flows under and is compressed by the screed plates 136. The screed assembly 130 may also include a tamper bar adjacent the front of the screed frame 112 that can be rapidly and repeatedly moved upward and downward in the vertical direction 135 to tamper and compact the paving material flowing underneath the screed plates 136.

Referring to FIG. 3, each screed plate 136 can be generally rectangular in shape, having a rectangular outline 150 or perimeter, and can have a lower material contacting surface 152 adapted for moveable contact with the paving material and an upper frame attachment surface 154 opposite the lower material contacting surface. When the screed plates 136 are attached to the screed frame, the lower material contacting surface 152 is oriented to interface with the paving material that moves thereunder and the upper frame attachment surface 154 is in abutting contact with the screed frame. The upper frame attachment surface 154 can be flat and planar, although in some configurations, the upper frame attachment surface 154 can include mounting and attachment features to secure the screed plate 136 to the screed frame.

The lower material contacting surface 152 and the upper frame attachment surface 154 can extend between a forward leading edge 156 and a rearward trailing edge 158 of the rectangular plate outline 150. The terms forward leading edge 156 and a rearward trailing edge 158 are in reference to the travel direction 108 of the mobile paver and reflect movement of the screed plate 136 with respect to the work surface.

The forward leading edge 156 and a rearward trailing edge 158 may be linear and parallel to each other in the lateral direction 134. The distance between the forward leading edge 156 and a rearward trailing edge 158 corresponds to the longitudinal length of the screed plate 136 and may be coextensive with the length of the screed frame in the travel direction 108. To assist directing the paving material underneath the screed plate 136, the forward leading edge 156 may be slightly turned up in the vertical direction 135.

The rectangular plate outline 150 can also include parallel first and second side edges 160, 162 that extend between the forward leading edge 156 and the rearward trailing edge 158. The distance between the first and second side edges 160, 162 corresponds to the width of the screen plate 136 in the lateral direction 134. The first and second side edges 160, 162 can be linear and flat to abut seamlessly against the side edges of adjacent screed plates 136 when attached to the screed frame.

During the paving operation, the paving mat 106 produced may assume desired physical characteristics or properties during the sliding contact with the screed plates 136 of the floating screed assembly. For example, to produce a consistently planar paving mat, the lower material contacting surface 152 of the screed plate 136 can have a correspondingly smooth and flat structure to reduce any surface roughness imparted to the paving mat. However, to produce a desired surface texturing of the paving mat, the screed plates 136 in accordance with the disclosure may be configured with a tining or texturing structure 164 that is physically included on the lower material contacting surface 152.

For example, the texturing structure 164 may have a three dimensional spatial extension and can be located adjacently along the rearward trailing edge 158 of the screen plate 136. The texturing structure 164 may extend across the width of the screed plate 136 in the lateral direction 134. Moreover, the texturing structure 164 can be situated proximately to the rearward trailing sedge 154 and may comprise the rearward 10% or 5% of the overall longitudinal length measured in the travel direction 108 of the lower material contacting surface 152. In an embodiment, the remaining 90% to 95% of the lower material contacting surface 152 is planar and forms a planar, flat surface, 168 for flattening and compressing the loose aggregate paving material during initial compaction.

In an embodiment, the texturing structure 164 can include a plurality of laterally arranged and spaced apart beadlike or bump-like rigid protuberances 166 that descend in the vertical direction 135 from the plane of the otherwise flat lower material contacting surface 152. The plurality of rigid protuberances 166 can be laterally spaced apart and aligned in a lateral row that is parallel with the lateral direction 134. The plurality of rigid protuberances 166 in the lateral row of the texturing surface 164 are therefore aligned parallel with the rearward trailing edge 154 and perpendicular to the travel direction 108 of the screed plate 136 when moving in the travel direction 108.

In an example, the rigid protuberances 166 can have a triangular shape such as a delta protuberance 170 as shown in Detail A. The delta protuberance 170 may have a triangular base 172 at the interface with the plane of the lower material contacting surface 152 that vertically tapers to a protuberance apex 174 in the vertical direction 125. The triangular delta protuberance 170 may also be elongated or extended and can include a leading vertex or leading edge 176 that extends between the triangular base 172 and the protuberance apex 174 that is oriented forwardly in the travel direction 108. The leading edge 176 will initially contact the paving material during movement of the screed plate in the travel direction 108 and therefore forms a narrower or sharper angle to reduce friction and drag. The distance between the triangular base 172 and the protuberance apex 174 establishes the protuberance height 178 in the vertical direction 135 that corresponds with the distance the triangular delta protuberance 170 descends from the plane of the lower material contacting surface 152.

In another example shown in Detail B, the rigid protuberance 166 may be an ovular protuberance 180 having a rounded shape projecting from an oval base 182 with faces that curve toward and converge at the protuberance apex 184 spatially below the plane of the lower material contacting surface 152. The ovular protuberance 180 can also be elongated or extended in the travel direction 108 and can include a leading surface or rounded leading face 186 intended to encounter the paving material and which may have a reduced or lower angle with respect to the vertical direction 135. The ovular protuberance 180 can have a protuberance height 188 in the vertical direction 135 corresponding to the distance between the oval base 182 and the protuberance apex 184. The rigid protuberances 166 of the texturing pattern 164 can have other suitable three-dimensional shapes and the foregoing descriptions are examples only.

Referring to FIG. 2, the screed plates 136 configured with the texturing structure can create surface texturing such as a tining pattern 190 into the paving mat 106 formed behind the screed assembly when moving in the travel direction 108. The tining pattern 190 may include a plurality of linear continuous striations or longitudinal tining grooves 192 parallel with one another and aligned with the travel direction 108. The tining pattern 190 is intended to roughen the mat surface 194 of the paving mat 106 to improve traction and skid resistance with respect to vehicles traveling thereon. For example, the longitudinal tining pattern 190 increases the frictional interaction with the pneumatic tires on vehicles to maintain traction and reduce skidding, including when precipitation is present. The tining grooves 192 of the tining pattern 190 may also function to channel and direct water and moisture away from the mat surface 194.

The tining pattern 190 produced by the screed plates 136 can be characterized by aligning the plurality of parallel longitudinal tining grooves 192 with the travel direction 108. Longitudinal alignment of the tining grooves 192 reduces noise levels caused by rolling contact between the tires and the tining pattern 190, for example, in comparison with lateral or transverse tining patterns in which the tining grooves are aligned in the lateral direction 134. The longitudinal tining pattern 190 may also extend across the width of the paving mat 106 in the lateral direction 134. In an extendable screed assembly 130, this can be accomplished by including the texturing pattern on each of the screed plates 136 attached to the main screed section 142 and the extend screed sections 144 so that the tining pattern 190 is laterally coextensive with the width of the screed frame 138.

The physical configuration of the tining pattern 190 can be adapted to account for vehicle speed, anticipated weather conditions, composition of the paving material, etc. Referring to Detail C, the tining grooves 192 of the tining pattern 190 are physically empty spaces formed into the material of the paving mat 106 vertically downwards from the mat surface 194 in the vertical direction 135. The tining grooves 192 may be characterized as having a groove width 196 in the lateral direction and a groove depth 198 downwards from the mat surface 194 in the vertical direction. In an example, the groove width 196 may be approximately 3 mm and the groove depth 198 may be approximately 3 mm, although the dimensions will vary upon application. In general, narrower, deeper tining grooves 192 may be preferable to wider shallower tining grooves. The tining pattern 190 can also be characterized as having a groove pitch 199 corresponding to the distance between adjacent tining grooves 192 in the lateral direction 134. In an example, the groove pitch 199 can be 10 mm to 20 mm.

The surface treatment provided by the tining pattern 190 can be referred to as macro-texturing. Macro-texturing can be characterized in part by the formation and inclusion of physical features in the paving mat to enhance surface roughness and improve rolling friction and vehicular traction. Macro-texturing may be distinguished from other surface texturing such as micro-texturing that may be achieved by altering the mix and aggregate size of the paving material. Macro-texturing is also distinguishable from other surface treatments like mega-texturing in which physically larger variations are formed into the paved surface such as rumble strips.

Referring to FIG. 3, in an embodiment, the plurality of rigid protuberances 166 making up the textured pattern 164 can be integrally cast as part of the screed plate 136. For example, if the screed plate 136 is made of a metal like steel or nickel alloy, the rigid protuberances 166 can be formed by corresponding dimples or cavities in the casting mold. The integrally cast rigid protuberances 166 are molecularly associated with the material of the screed plates 136 for durability. In another embodiment, the rigid protuberances 166 can be separately formed and connected to the lower material contacting surface 152 of the screed plate 136 by welding or brazing. Connection by welding or brazing allows the rigid protuberances 166 to be formed of a material different from and dissimilar to the screed plates 136, but may result in a weaker joint structure and possible detachment.

The texturing structure may assume different forms, shapes, and arrangements. For example, referring to FIG. 4, a rectangular screed plate 200 having a lower material contacting surface 202 and an opposite attachment surface 204 extending between the forward leading edge 206 and the parallel rearward trailing edge 208 can include the texturing structure in the form of a texturing profile 210 formed along the rearward trailing edge 208. Instead of protuberances descending from the lower material contacting surface 202, the texturing profile 210 may correspond to the physical shape and profile of the trailing edge 208. The texturing profile 210 can be embodied as serrations 212 formed along the lateral width of the rearward trailing edge 208 in the lateral direction 134. The serrations 212 can include a series of sharp tooth-like projections aligned in a lateral row and extending in the vertical direction 135. The serrations 212 structurally alters the smooth flat finish of the lower material contacting surface 202.

To fabricate the texturing profile 210 into the rearward trailing edge 208 of the screed plate 200, the serrations 212 may be produced by corresponding shape bumps disposed on the casting mold. In another embodiment, the screed plate 210 may be cast flat and the serrations 212 can be machined by a cutting or milling tool into the lower material contacting surface 202 upon removal from the casting mold. In another embodiment, the texturing profile 210 can be foraged into the lower material contacting surface 202 with a press or hammer, for example, in a hot working process at elevated temperatures.

The texturing profile 210 formed on the trailing edge 208 corresponds to the shape and pattern of the surface texturing formed into the paving mat 106. For example, serrations 212 of the texturing profile 210 can have a height or amplitude 214 that corresponds with the groove depth 198 and can have a serration pitch 216 that corresponds to the groove pitch 199. Where the serrations 212 of the texturing profile 210 are shaped as triangular teeth, the produced tining pattern will be shaped as a corresponding periodic series of ridges. In other examples, the texturing profile 210 may be configured as a periodic undulating sine wave 220 as shown in Detail D or as a periodic square wave 222 as shown in Detail E, and the tining pattern in the paving mat may have corresponding shapes.

Referring to FIG. 5, a rectangular screed plate 300 having a lower material contacting surface 302 and an opposite attachment surface 304 extending between the forward leading edge 306 and the parallel rearward trailing edge 308 can include the texturing structure in the form of a texturing rake 310 along the rearward trailing edge 308. For example, the texturing rake 310 can include a plurality of individual tines 312 that are short cylindrical rods protruding vertically downward from the lower material contacting surface 302 in the vertical direction 135. The plurality of tines 312 are aligned in series to form a row parallel to the rearward trailing edge 308 and aligned in the lateral direction 134 to extend across the width of the screed plate 300.

To abrasively interact with the paving material, the tines 312 can be made of a metallic material such as steel bar stock. In an embodiment, to produce the texturing rake 310, individual tines 312 can be directly attached to the screed plate 300, for example, by threaded interfaces with corresponding threaded holes in the lower material contacting surface 302. In another embodiment, the plurality of tines 312 can be joined in a row to a common elongated rail or bar that is attached to the screed plate 300 laterally adjacent to rearward trailing edge 308.

The arrangement of the plurality of tines 312 in the texturing rake 310 can be configured to produce the surface texturing such as the tining pattern 190 shown in FIG. 2. For example, the individual tines 312 may each have a tine height 314 descending from the lower material contacting surface 302 that corresponds to the groove depth 198 and can have tine diameter 316 that corresponds to the groove width 196. The texturing rake 310 can also have a tine pitch 318 that spaces apart the individual tines 312 in the lateral direction 134 and which corresponds to the groove pitch 199 of the paving mat 106.

In an embodiment, the texturing structure can interact with other physical features on the screed plate to cooperatively improve the characteristics and properties of the paving mat. For example, referring to FIG. 6, there is illustrated a rectangular screed plate 400 having a lower material contacting surface 402 and an opposite attachment surface 404 extending between the forward leading edge 406 and the parallel rearward trailing edge 408. Situated along the rearward trailing edge 408 of the screed plate 400 can be the texturing structure 410. The texturing structure 410 can be configured in accordance with any of the foregoing descriptions.

To improve the mixing of the paving material before imparting the surface texturing, the screed plate 400 can include a three dimensional textured pattern 412 formed into the lower material contacting surface 402. The textured pattern 412 can create a variability and unevenness to the topology of the lower material contacting surface 402 with respect to the vertical direction. For example, the textured pattern 412 can include a plurality of protruding polyhedron elements 414 that project downwardly in the vertical direction 135 and that are spaced apart from each other to define empty troughs and indentations that function as material channels 416. The textured pattern 412 can extend from the forward leading edge 406 toward the rearward trailing edge 408 of the screed plate 400 can the plurality of protruding polyhedron elements 414 can be arranged in a regular matrix of rows and columns, although alternatively, the textured pattern 412 can be irregular.

The protruding polyhedron elements 414 can be configured as diamond-shaped pyramids, although the protruding polyhedron elements may have other suitable shapes such as rhombic, kites, etc. In comparison with the texturing structure 410 along the trailing edge 408, the protruding polyhedron elements 412 may be substantially larger and may have a base length 420 in the travel direction 108 of, for example, approximately 4 inches or 100 millimeters and a base width 422 in the lateral direction 134 of, for example, approximately 2 inches or 50 millimeters. Furthermore, the protruding polyhedron elements 414 may have a substantially larger spatial extension in the vertical direction 135 than the texturing structure 410. The vertical heights of the plurality of protruding polyhedron elements 414 may gradually dimension towards the rearward trailing edge 408 so that the textured pattern 412 appears flatter and smoother with respect to the lower material contacting surface 402.

The material channels 416 defined between the spaced-apart protruding polyhedron elements 414 can have varying sizes and dimensions. As a result of the arrangement of the protruding polyhedron elements 414 in the texturing pattern 412, the material channels 416 may be generally aligned with the travel direction 108 running between the forward leading edge 406 toward the rearward trailing edge 408. Furthermore, because of the geometric shapes of the protruding polyhedron elements 414, the material channels 418 can be crooked or laterally shifted with respect to the lateral direction 134. For example, the material channel 416 can repeatedly widen and narrow along the travel direction 108 in resemblance with the tapering polyhedron shapes of the protruding polyhedron elements 414. Accordingly, the material channels 416 appear to laterally shift and zig-zag within the textured pattern 412.

During the paving operation, the paving material moving underneath the forward leading edge 406 of the screed plate 400 encounters the textured pattern 412 and is directed by the protruding polyhedron elements 414 into the material channels 416. The laterally shifting geometry and the changing widths of the material channels 416 continues to move and displace the paving material during relative motion with lower material contacting surface 402 which continuously mixes the aggregates and binder in the paving material. As a result, the paving material may be more homogenous because of the interaction with the textured surface 412 on the screed plate. After paving material passes through the textured pattern 412, the material encounters the texturing structure 410 at the rearward trailing edge 408 that can impart the surface texturing to the homogenously mixed paving mat.

INDUSTRIAL APPLICABILITY

Use of the texturing structure 164 on a screed plate 136 for surface texturing of a paving mat 106 can be described with continued reference to the proceeding figures. For example, referring to FIGS. 1 and 2, in accordance with operation of the illustrated mobile paver 100, paving material 108 in loose, granular form, including aggregates of different sizes (i.e. coarse and fine) in a binder or bitumen mixture is delivered to the hopper 110, directed through the chassis 112 by the conveyor system 116, and discharged to the auger 132 to be laterally spread over the work surface 104 in the lateral direction 134. The screed assembly 130, which may be attached to the mobile paver 100, can be towed over the deposited paving material 104 so that the screed plates 136 attached to the underside of the screed frame 138 move over the paving material in the travel direction 108.

The loose aggregate paving material 102 that is laterally distributed on the work surface 104 encounters and is directed under the forward leading edge 156 of the screed plate 136 to be initially compressed and smoothed by the smooth planar extension of the lower material contacting surface 152. For example, the weight of the screed assembly 130 and the relative motion of the lower material contacting surface 152 in the travel directions compacts the loose paving material 102 into the denser paving mat 106. Vibration caused by eccentric weights rotating with respect to the screed frame may assist compaction.

The compressed and flattened paving material progresses toward the rearward trailing edge 158 due to relative movement of the screed plate 136 in the travel direction 108 to encounter the texturing structure 164 with the vertically protruding plurality of rigid protuberances 166. The rigid protuberances physically displace and move the paving material laterally away with respect to the lateral direction 108 as the protuberances pass through the material in the travel direction 108. Laterally displacing the paving material as a result of moving the texturing structure 164 in the travel direction 108 consequentially forms the plurality of tining grooves 192 in the mat surface 194 that may spatially and dimensionally correspond to the size and shape of the plurality of rigid protuberances 166.

The compressed paving mat 106 is provided with a tining pattern 190 as a result of the concurrent actions and operations of the floating screed assembly 130 and the texturing structure 164 included thereon. For example, the screed plate 130 simultaneously compacts the paving material 102 and creates the tining pattern 190 as the lower material contacting surface 152 moves with respect to the paving material 102 in the travel direction 108. Displacement and formation of the tining grooves 192 is assisted by the relatively elevated temperature and the low density of the recently dispensed paving material 102. In particular, the hot paving material 102 is more easily displaced before cooling and hardening, and inclusion of inductive heaters in the screed assembly can assist in forming the tining pattern 190. The displaced paving material 102 is still integrally joined as part of the paving mat 108 after passing of the screed plate 136, and may become permanently set and situated in the material of the paving mat 106 after cooling and hardening.

Inclusion of the texturing structure on the screed plate has advantages over other methods of surface texturing. The concurrent creation of the compacted paving mat and formation of the tining pattern avoids subsequent paving operations and machines such as diamond grinders and cutters. Further, the in situ creation of tining grooves in the paving mat avoids subsequent cutting and milling of the paving material reducing dust, debris, and waste that is an inherent part and a by-product of other surface texting methods. Additionally, by forming the tining grooves while the paving material is readily displaceable prior to hardening, the tining grooves may be structurally stronger and more durable. These and other possible advantages of the disclosure should be apparent from the above detailed description and drawings.

It will be appreciated that the foregoing description provides examples of the disclosed system and technique. However, it is contemplated that other implementations of the disclosure may differ in detail from the foregoing examples. All references to the disclosure or examples thereof are intended to reference the particular example being discussed at that point and are not intended to imply any limitation as to the scope of the disclosure more generally. All language of distinction and disparagement with respect to certain features is intended to indicate a lack of preference for those features, but not to exclude such from the scope of the disclosure entirely unless otherwise indicated.

Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context.

The use of the terms “a” and “an” and “the” and “at least one” or the term “one or more,” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of the term “at least one” followed by a list of one or more items (for example, “at least one of A and B” or one or more of A and B”) is to be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context.

Accordingly, this disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.