Screed Plate for Paving Machine

Abstract

A screed plate for a screed assembly to be towed by a mobile paver has a lower material contacting surface for compaction of paving material that includes textured pattern and an undulating pattern. The textured pattern includes a plurality of protruding elements and corresponding channeling grooves that receive and arrange the paving material into a plurality of windrows. The undulating pattern includes one or more arcuate ridges that traverse the plurality of channeling grooves to interact and blend together the plurality of windrows.

Description

TECHNICAL FIELD

[0001] 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 arranging the paving material to produce a paving mat.BACKGROUND

[0002] 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.

[0003] 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.

[0004] 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. U.S. Patent 10,156,050 (the ’050 patent”) describes a screed plate having a textured configuration to improve the compaction process and density of the resulting paving mat. The ’050 patent, in particular, describes that texturing of the underside of the screed plate facilitates sorting and distribution of the aggregates in the paving material and results in a more durable and denser paved surface.SUMMARY

[0005] The disclosure describes, in one aspect, a screed plate for a screed assembly towed by a mobile paver. The screed plate includes a forward leading edge, a rearward trailing edge parallel to the forward leading edge, an upper frame attachment surface extending between the forward leading edge and the rearward trailing edge, and a lower material contacting surface to compact and compress paving material sliding underneath the screed plate. The lower material contacting surface may further include a textured pattern that is contiguous to the leading edge and has a plurality of protruding elements and a plurality of channeling grooves formed between the plurality of protruding elements. The lower material contacting surface can also include an undulating pattern that is contiguous to the trailing edge and that has one or more arcuate ridges traversing at least a portion of the plurality of channeling grooves and parallel to the trailing edge. The undulating pattern can function to reduce or visibly blend the paving windrows that may be produced in the paving mat by the plurality of channeling grooves.

[0006] In another aspect, the disclosure describes a method of laying a paving mat by operation of a mobile paver equipped with a floating screed. The method involves receiving paving material into the hopper of the mobile paver that may be traveling longitudinally in a travel direction. The paving material is conveyed from the hopper to an auger arranged laterally and perpendicular to the travel direction of the mobile paver and is laterally distributed 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 directing the into a plurality of channeling grooves defined by a textured pattern on the screed plate to form a plurality of paving windrows. To reduce the visible appearance of the paving windrows, the method may physically interact and engage the plurality of windrows through sliding contact with an undulating pattern on the screed plate.

[0007] In yet another aspect, the disclosure describes a screed plate for a screed assembly towed by a mobile paver. The screed plate includes a forward leading edge, a rearward trailing edge parallel to the forward leading edge, an upper frame attachment surface extending between the forward leading edge and the rearward trailing edge, and a lower material contacting surface to compact and compress paving material sliding underneath the screed plate. The lower material contacting surface includes a textured pattern located toward the forward leading edge that has a plurality of protruding elements and a plurality of channeling grooves located between the plurality of protruding elements. The lower material contacting surface also includes an undulating pattern located toward the rearward trailing edge that has a plurality of arcuate ridges each having a ridge height and extending parallel to the rearward leading edge. The plurality of arcuate ridges are arranged in successive lateral ridge rows with decreasing ridge heights as the undulating pattern progresses toward the rearward trailing edge.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] 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.

[0009] 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 screed plates attached to the underside of the screed frame.

[0010] FIG. 3 is a perspective view of the material contacting underside of a screed plate with a texturing pattern having a plurality of protruding elements and an undulating pattern having a plurality of arcuate ridges that cooperate to physically alter the appearance of the paving mat in accordance with the disclosure.

[0011] FIG. 4 is a plan view diagram of the lower material contacting underside of the screed plate indicating the physical movement of the paving material and application of compressive forces during sliding contact with the textured pattern and the undulating pattern.

[0012] FIG. 5 is a side elevational view of the screed plate showing the plurality of arcuate ridges arranged in successive lateral ridge rows and having decreasing ridge heights.

[0013] FIG. 6 is a perspective view of the material contacting underside of the screed plate with an undulating pattern having continuous and discontinuous arcuate ridges.DETAILED DESCRIPTION

[0014] 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.

[0015] 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.

[0016] To direct the loose, granular paving material rearward from the hopper 110, the mobile paver100 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.

[0017] 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.

[0018] 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 latent 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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 compressed flat paving mat 106 across the lateral direction 134 and extending rearward of the screed assembly 130 in the travel direction 108.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] To facilitate formation and compaction of the paving mat 106 during the paving operation, the screed plate 136 can include structural features designed to physically interact with the paving material 102. For example, to improve mixing of the paving material 102 passing underneath the screed plate 136, the lower material contacting surface 152 can include a textured pattern 164 structurally formed over at least a portion of the surface area. The textured pattern 164 can include a three dimensional structural topology of protruding elements 166 and corresponding channeling grooves 168 located there between that impress an unevenness to the screed plate 136. The protruding elements 166 can be solid geometric structures shaped, for example, as polyhedronal pyramids and the channeling grooves 168 may correspond to the varying and shifting spaces or gaps between the spaced apart geometric elements. The three dimensional topology of the textured pattern 164 thus has structural variation with respect to the vertical direction 135.

[0033] The geometric shapes and arrangement of the protruding elements 166 and channeling grooves 168 can have any suitable design and configuration. For example, the geometry of the protruding elements 166 may be rhombic, triangular pyramids or deltahedron, conical or truncated cones, curvilinear or globular, etc. Further, the size and number of protruding elements 166 and the corresponding channeling grooves 168 may increase or decrease in the travel direction 108 between the forward leading edge 156 and the rearward trailing edge 158. The textured pattern 164 can be formed in the material contacting surface 152 of the screed plate by casting, stamping, or machining. In an example, the protruding elements 166 of the textured pattern 164 can be attached by mechanical joining techniques such as welding, brazing, adhesives, or threaded fasteners. In an example, the protruding elements 166 can be provided by an additive manufacturing process such as three-dimensional printing.

[0034] During a paving operation, the structural unevenness and topographic variability of the textured pattern 164 may displace larger aggregates within the paving material. For example, the solid protruding elements 166 may direct the paving material into the channeling grooves 168 that assume a staggered arrangement corresponding to the spacing and shape of the protruding elements. The movement and shifting of the paving material received in and passing through the channeling groove 168 may further embed the aggregates within the fines and binders, resulting in a denser and smoother paving mat. Further, the additional mixing caused by the textured pattern 164 may result in a more homogenous consistency of the aggregates and fines within the paving material 102, also resulting in improvement in the characteristics of the produced paving mat 106.

[0035] The process of directing the paving material into the plurality of channeling grooves 168 extending longitudinally within the textured pattern 164 arranges the paving material, including various sized aggregates therein, into a plurality of paving windrows 169, indicated in FIG. 2, that are formed following the trailing edge 158 of the screed plate 136 in the travel direction 108. The paving windrows 169 may appear as visible linear lines or stripes in the paving mat 106 parallel to the travel direction 108. The paving windrow 169 may result from the segregation and concentration of aggregates and fines within the paving material due to interaction with the textured pattern 164.

[0036] In some instances, the paving windrows 169 may be primarily visible, appearing as distinct lines or strips distinguishable by shading or color, while the topology of the paving mat 106 remains planar and flat. In some instances, the paving windrow 169 may result in geometric unevenness to the topology of the paving mat, for example, as may occur after a period of time during which the paving material 102 settles. The paving windrow 169 may be visibly or aesthetically displeasing and unattractive, or may complicate subsequent paving operations.

[0037] To reduce or eliminate the paving windrows 169, the lower material contacting surface 152 can include an additional geometric structural pattern in the form of a plurality of waves, curves, or undulations that vary the topology of the lower material contacting surface with respect to the vertical direction 135. For example, geometric structures comprising an undulating pattern 170, including a plurality of rising and following waves, can be situated rearward of the textured pattern 164 with respect to the travel direction 108. The rearward location of the undulating pattern 170 with respect to the textured pattern 164 results in physical interaction with the paving material exiting the plurality of channeling grooves 168 and forming the paving windrows 169. For example, the undulating pattern 170 can be located between the first and second side edges 160, 162 in the lateral direction 134 so as to laterally traverse the textured pattern 164 and in particular the plurality of channeling grooves 168 therein.

[0038] To structurally form the undulating pattern 170, one or more curved shapes such as arcuate ridges 172 can be included on the lower material contacting surface 152 of the screed plate 136. The arcuate ridges 172 can be linear, elongated structures that extend generally between the first and second side edges 160, 162 and that are aligned parallel with the rearward trailing edge 158. Each of the one or more arcuate ridges 172 can include a curved surface or ridge face 174 that protrudes outwards from the body of the screed plate 136 with respect to the vertical direction 135. For example, the arcuate ridges 172 may each includes an elongated ridge base 176 from which the curved ridge face 174 extends toward a ridge crest 178, indicated in dashed lines, that extend the lateral width of the screed plate 136 between the first and side edges 160, 162 and parallel to the rearward trailing edge 158.

[0039] Each arcuate ridge 172 can be straight and linear, extending in the lateral direction 134 with the ridge base 176 adjacent the lower material contacting surface 152 having dimensional width corresponding to the travel direction 108 from which the curved ridge face 174 curve and converges along the ridge crest 178, which may correspond to a singular linear line that is dimensionally smaller and thinner than the ridge base 176 in the travel direction 108. The distance between the ridge base 176 and the ridge crest 178 can correspond to and defines a ridge height 180 in the vertical direction 135. Moreover, when the undulating pattern 170 includes a plurality of parallel arcuate ridges 172 located adjacent each other as shown in FIG. 3, a corresponding plurality of undulating furrows 182 or troughs are defined within the gaps between the adjacent arcuate ridges 172. The plurality of undulating furrows 182 similarly extend in parallel alignment with the rearward trailing edge 158 of the screed plate 136 and the geometry of the undulating furrows 182 inversely corresponds with the shape of the curved ridge faces 174.

[0040] The plurality of arcuate ridges 172 may be lateral continuous in physical structure between the first and second side edges 160, 162 of the screed plate 136 such that the arcuate ridges and the corresponding undulating furrows 182 traverse the plurality of channeling grooves 168 in the textured pattern in the lateral direction 134. The undulating pattern 170 including arcuate ridges 172 and the undulating furrows 182 can be formed in the screed plate by casting, stamping, or machining.

[0041] The undulating pattern 170 functions to mechanically interact with and work the paving material passing behind the textured pattern 164 of the lower material contacting surface 152. For example, the rising and falling geometry associated with the alternating arrangement of the arcuate ridges 172 and the undulating furrows 182 applies a variable compacting force to the paving material during sliding contact with the lower material contacting surface 152. The alternating application and release of force to the paving material by the undulating pattern 170 briefly and repeatedly presses or squeezes then eases the forces applied to the paving material, resulting in relative displacement and dispersion of the aggregates, fines, and fluids within the paving materials. The physical, mechanical working of the paving material due to interaction with the undulating pattern 170 results in blending, amalgamation, and merging of the plurality of paving windrows 169 to make the stripes visibly less noticeable or to disappear.

[0042] For example, with reference to FIG. 2, the repeated application and release of compressive pressing forces due to physical interaction with the undulating pattern 170 can displace smaller granular fines and oils in the paving material 102 vertically upwards in the paving mat 106. The accumulation of such materials at the top surface of the paving mat 106 can blend and reduce the striped appearance or discoloring attributable to the paving windrows 169. Furthermore, the undulating pattern 170 can transmit forces deeply into the deposited paving material 102 to improve settling of the aggregates and the density of the paving mat 106.

[0043] Referring to FIG. 4, in an example, the undulating pattern 170 can include a plurality of arcuate ridges 172 that are arranged in successive lateral ridge rows 190. Each of the arcuate ridges 172 in the successive lateral ridge rows 190 can be parallel to the forward leading edge 156 and rearward trailing edge 158. In the illustrated example, the undulating pattern 170 can include a first lateral ridge row 192 that is located between the forward leading edge 156 and the rearward trailing edge 158 and that is proximate to the textured pattern 164. The undulating pattern 170 may also include a second lateral ridge row 194 located rearward of the first lateral ridge row 192 and a third lateral ridge row 196 that is contiguous with and that extends along the rearward trailing edge 158. The successive lateral ridge rows 190 may include fewer or more arcuate ridges 172 than as illustrated.

[0044] The dimensions and geometric shapes of each of the arcuate ridges 172 in successive lateral ridge rows 190 may differ and vary with respect to one another. For example, referring to FIG. 5, the arcuate ridges 172 in the first lateral ridge row 192 can be dimensionally larger, such as having a greater ridge height 182 and wider ridge base 176, than the arcuate ridges in the second and third lateral ridge rows 194, 196. Accordingly, the dimensional sizes of the arcuate ridges 172 gradually diminishes and decreases as the successive lateral ridge rows 190 progress rearward in the travel direction 108 toward the rearward trailing edge 158.

[0045] Because the ridge heights 182 of the arcuate ridges 172 reduces between the first, second, and third lateral ridge rows 192, 194, 196, the vertical dimension of the undulating pattern 170 in the vertical direction 135 likewise gradually decreases toward the rearward trailing edge 158 of the lower material contacting surface 152. The gradual reduction in height of the undulating pattern 170 can vary and alter the application and release of compressive or compacting forces directed to paving mat by the screed plate 136.

[0046] In an embodiment, the screed plate 136 may include a lateral leveling band 198 that is located immediately adjacent to the trailing edge 158. The lateral leveling band 198 can be characterized by the absence of any protruding elements 166 associated with the textured pattern 164 or arcuate ridges 172 associated with the undulating pattern 170 and thus has a flat, planar configuration. The lateral leveling band 198 can extend in the lateral direction 134 between the first and second side edges 160, 162 and can be longitudinally located between the undulating pattern 170 and the trailing edge 158 in the travel direction 108, and can occupy any suitable fraction of the longitudinal length of the screed plate 136 in the travel direction 108. The vertical flatness of the lateral leveling band 202 may function to further compact and smooth out the paving material moving underneath the screed plate 136.

[0047] The arrangement and configuration of the plurality of arcuate ridges 172 in the undulating pattern 170 may vary or differ. Referring to FIG. 6, in an example, an undulating pattern 200 can include one or more discontinuous arcuate ridges 202 that protrude from the lower material contacting surface 152 of the screed plate 136. The discontinuous arcuate ridges 202 may be curved in geometric shape and may define inversely corresponding undulating furrows 208 between the individual ridge lines. The discontinuous arcuate ridges 202 can be parallel to the rearward trailing edge 158 and located between the first and second side edges 160, 162, but may be discontinuous or segmented.

[0048] For example, each of the discontinuous arcuate ridges 202 can include a plurality of individual arcuate ridge segments 204 that are laterally separated by corresponding lateral ridge gaps 206. The arcuate ridge segments 204 of each arcuate ridge 202 can be laterally aligned with one another in the lateral direction 134 and thus parallel to the rearward trailing edge 158. The arcuate ridge segments 204 can have a curved or arcuate shape, including a curved exterior surface or curved ridge face 210 that curves in the vertical direction 135 between a segment base 212 and a segment crest 214. The curved shaped of the arcuate ridge segments 202 causes similar physical interaction with the paving material as described with respect to the continuous arcuate ridges 172 in FIGS. 3-5 above.

[0049] In a possible example and in comparison with the symmetrical arcuate ridges described above, the arcuate ridge segments 204 of the discontinuous ridges 202 may be asymmetrical in shape. As shown in detail, the asymmetrical arcuate ridge segments 204 can be characterized has having an increased or budged volume forward or rearward of the segment crest 214. The portion of the asymmetrical arcuate ridge segments 204 opposite of the segment crest 214 is thinner and forms a shaper or more tapered angle between the curved face 210 and the segment base 212. The curved ridge face 210 of the asymmetrical arcuate ridge segments 204 assumes the shape of an irregular curve.

[0050] In other examples, the discontinuous arcuate ridges 202 can be symmetrical in shape as described above. Relatedly, the continuous arcuate ridges 172 described in FIGS. 3-5 may be asymmetrical in shape.

[0051] The lateral ridge gaps 206 physically space apart and separate the plurality of ridge segments 204 in the lateral direction, and may reduce the material and weight of the screed plate 136. The lateral ridge gap 206 between the successive rows of arcuate ridges may align with each other or may be laterally staggered in alignment with each other in the travel direction 108. In an example, the discontinuous arcuate ridges 202 of the undulating pattern. 200 can also be physically separated and spaced apart from each other with respect to the travel direction 108. For example, in comparison with the continuous alignment of the successive lateral ridge rows 190 in FIG. 4, the discontinuous arcuate ridges 202 can be separated by longitudinal ridge gaps 216. The longitudinal ridge gaps 216 can have any suitable or appropriate spacing or dimensions to create a desired pitch between the plurality of discontinuous arcuate ridges 202 in the undulating pattern 200. The lateral ridge gaps 216 can increase the dimension and volume of the undulating furrows 208 in the undulating pattern 200. The longitudinal ridge gaps 216 can also be utilized to physically separate and space apart the continuous arcuate ridges 172 in FIGS. 3-5.

[0052] The arcuate ridge segments 204 can be located rearward of the channeling grooves 168 in the textured pattern 164 to interact with the paving windrows. For example, the arcuate ridge segments 204 can be aligned to traverse the channeling grooves 168 in the travel direction 108 so that the segments will physically encounter and interact with the plurality paving windrow formed by a trailing form the plurality of channeling grooves 168. In an example, the number of laterally aligned arcuate ridge segments 204 may correspond with the number of channeling grooves 168, although in other examples, the numbers may differ. In an example, to produce a smooth, planar upper topology on the paving mat, the rearward-most arcuate ridge 218 of the undulating pattern 200 can have a continuous extension between the first and second side edges 160, 162 of the screed plate 136. The continuous configuration of the rearward-most arcuate ridge 218 can function to reduce or eliminate visual distortions or effect of the lateral ridge gaps 206.INDUSTRIAL APPLICABILITY

[0053] Operation and effectiveness of the undulating pattern 170 on a screed plate 136 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 102 in the travel direction 108.

[0054] 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. The paving material 102 encounters and physical interacts with the textured pattern 164 that is contiguously adjacent to the forward leading edge 156 and a portion of the paving material may be directed into the plurality of channeling groove 168 due to contact with and displacement by the protruding elements 166.

[0055] For example, referring to FIG. 4 and as indicated by solid arrows 220, the paving material gathers and passes through the channeling grooves 168. The laterally shifting arrangement or zig-zag geometry of the channeling grooves 168 corresponding to and resulting from the geometric shapes of the protruding elements 166 may cause larger aggregates to homogenously mix and disperse in the mixture of paving material, but may result in paving windrows 169, indicated in dashed arrows, corresponding in location with the channeling grooves 168, to appear in the paving mat 106.

[0056] The distributed paving materials progress rearward toward the undulating pattern 170 due to relative movement of the screed plate 136 in the travel direction 108. The protruding geometry of the plurality of arcuate ridges 172 due to the ridge heights 180 applies compressive forces into the paving mat 106 in the vertical direction 135 as indicated by concentric circles representing forces arrows 222. Furthermore, the undulating furrows 182 located between the arcuate ridges 172 may relieve the applied forces as indicated by the circled crosses representing relief arrows 224. For example, the compressive forces associated with the force arrows 222 may be laterally aligned with ridge crests 178 and the relief arrow can be located within the undulating furrows 182 with respect to the travel direction 108, although it should be appreciated that the location of the force and relief arrows 222, 224 is intended for reference and the magnitude of the actual applied and released force with vary with the changing geometry of the undulating pattern 170. In the examples wherein the arcuate ridges extends substantially between the first and second lateral edges 160, 162 to traverse the channeling grooves 168, the application of forces extends across the plurality of paving windrows 169 with respect to the lateral direction 134.

[0057] The alternating and repeated application and release of force caused by the undulating pattern 170, indicated by force arrows 222 and relief arrows 224, functions to mechanical work and knead the paving material during sliding contact with the screed plate 136. As described above, the alternating pressure and release can cause or draw the finer particles and oils to proceed toward the upper surfaces of the paving mat, blending or obscuring the paving windows 169. The produced paving mat may have a more uniform and aesthetically pleasing appearance due to the physical interaction with and manipulation by the undulating pattern 170 on the screed plate 136.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

Examples

Embodiment Construction

[0014]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 m...

TECHNICAL FIELD

[0001] 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 arranging the paving material to produce a paving mat.BACKGROUND

[0002] 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.

[0003] 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.

[0004] 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. U.S. Patent 10,156,050 (the ’050 patent”) describes a screed plate having a textured configuration to improve the compaction process and density of the resulting paving mat. The ’050 patent, in particular, describes that texturing of the underside of the screed plate facilitates sorting and distribution of the aggregates in the paving material and results in a more durable and denser paved surface.SUMMARY

[0005] The disclosure describes, in one aspect, a screed plate for a screed assembly towed by a mobile paver. The screed plate includes a forward leading edge, a rearward trailing edge parallel to the forward leading edge, an upper frame attachment surface extending between the forward leading edge and the rearward trailing edge, and a lower material contacting surface to compact and compress paving material sliding underneath the screed plate. The lower material contacting surface may further include a textured pattern that is contiguous to the leading edge and has a plurality of protruding elements and a plurality of channeling grooves formed between the plurality of protruding elements. The lower material contacting surface can also include an undulating pattern that is contiguous to the trailing edge and that has one or more arcuate ridges traversing at least a portion of the plurality of channeling grooves and parallel to the trailing edge. The undulating pattern can function to reduce or visibly blend the paving windrows that may be produced in the paving mat by the plurality of channeling grooves.

[0006] In another aspect, the disclosure describes a method of laying a paving mat by operation of a mobile paver equipped with a floating screed. The method involves receiving paving material into the hopper of the mobile paver that may be traveling longitudinally in a travel direction. The paving material is conveyed from the hopper to an auger arranged laterally and perpendicular to the travel direction of the mobile paver and is laterally distributed 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 directing the into a plurality of channeling grooves defined by a textured pattern on the screed plate to form a plurality of paving windrows. To reduce the visible appearance of the paving windrows, the method may physically interact and engage the plurality of windrows through sliding contact with an undulating pattern on the screed plate.

[0007] In yet another aspect, the disclosure describes a screed plate for a screed assembly towed by a mobile paver. The screed plate includes a forward leading edge, a rearward trailing edge parallel to the forward leading edge, an upper frame attachment surface extending between the forward leading edge and the rearward trailing edge, and a lower material contacting surface to compact and compress paving material sliding underneath the screed plate. The lower material contacting surface includes a textured pattern located toward the forward leading edge that has a plurality of protruding elements and a plurality of channeling grooves located between the plurality of protruding elements. The lower material contacting surface also includes an undulating pattern located toward the rearward trailing edge that has a plurality of arcuate ridges each having a ridge height and extending parallel to the rearward leading edge. The plurality of arcuate ridges are arranged in successive lateral ridge rows with decreasing ridge heights as the undulating pattern progresses toward the rearward trailing edge.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] 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.

[0009] 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 screed plates attached to the underside of the screed frame.

[0010] FIG. 3 is a perspective view of the material contacting underside of a screed plate with a texturing pattern having a plurality of protruding elements and an undulating pattern having a plurality of arcuate ridges that cooperate to physically alter the appearance of the paving mat in accordance with the disclosure.

[0011] FIG. 4 is a plan view diagram of the lower material contacting underside of the screed plate indicating the physical movement of the paving material and application of compressive forces during sliding contact with the textured pattern and the undulating pattern.

[0012] FIG. 5 is a side elevational view of the screed plate showing the plurality of arcuate ridges arranged in successive lateral ridge rows and having decreasing ridge heights.

[0013] FIG. 6 is a perspective view of the material contacting underside of the screed plate with an undulating pattern having continuous and discontinuous arcuate ridges.DETAILED DESCRIPTION

[0014] 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.

[0015] 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.

[0016] To direct the loose, granular paving material rearward from the hopper 110, the mobile paver100 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.

[0017] 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.

[0018] 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 latent 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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 compressed flat paving mat 106 across the lateral direction 134 and extending rearward of the screed assembly 130 in the travel direction 108.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] To facilitate formation and compaction of the paving mat 106 during the paving operation, the screed plate 136 can include structural features designed to physically interact with the paving material 102. For example, to improve mixing of the paving material 102 passing underneath the screed plate 136, the lower material contacting surface 152 can include a textured pattern 164 structurally formed over at least a portion of the surface area. The textured pattern 164 can include a three dimensional structural topology of protruding elements 166 and corresponding channeling grooves 168 located there between that impress an unevenness to the screed plate 136. The protruding elements 166 can be solid geometric structures shaped, for example, as polyhedronal pyramids and the channeling grooves 168 may correspond to the varying and shifting spaces or gaps between the spaced apart geometric elements. The three dimensional topology of the textured pattern 164 thus has structural variation with respect to the vertical direction 135.

[0033] The geometric shapes and arrangement of the protruding elements 166 and channeling grooves 168 can have any suitable design and configuration. For example, the geometry of the protruding elements 166 may be rhombic, triangular pyramids or deltahedron, conical or truncated cones, curvilinear or globular, etc. Further, the size and number of protruding elements 166 and the corresponding channeling grooves 168 may increase or decrease in the travel direction 108 between the forward leading edge 156 and the rearward trailing edge 158. The textured pattern 164 can be formed in the material contacting surface 152 of the screed plate by casting, stamping, or machining. In an example, the protruding elements 166 of the textured pattern 164 can be attached by mechanical joining techniques such as welding, brazing, adhesives, or threaded fasteners. In an example, the protruding elements 166 can be provided by an additive manufacturing process such as three-dimensional printing.

[0034] During a paving operation, the structural unevenness and topographic variability of the textured pattern 164 may displace larger aggregates within the paving material. For example, the solid protruding elements 166 may direct the paving material into the channeling grooves 168 that assume a staggered arrangement corresponding to the spacing and shape of the protruding elements. The movement and shifting of the paving material received in and passing through the channeling groove 168 may further embed the aggregates within the fines and binders, resulting in a denser and smoother paving mat. Further, the additional mixing caused by the textured pattern 164 may result in a more homogenous consistency of the aggregates and fines within the paving material 102, also resulting in improvement in the characteristics of the produced paving mat 106.

[0035] The process of directing the paving material into the plurality of channeling grooves 168 extending longitudinally within the textured pattern 164 arranges the paving material, including various sized aggregates therein, into a plurality of paving windrows 169, indicated in FIG. 2, that are formed following the trailing edge 158 of the screed plate 136 in the travel direction 108. The paving windrows 169 may appear as visible linear lines or stripes in the paving mat 106 parallel to the travel direction 108. The paving windrow 169 may result from the segregation and concentration of aggregates and fines within the paving material due to interaction with the textured pattern 164.

[0036] In some instances, the paving windrows 169 may be primarily visible, appearing as distinct lines or strips distinguishable by shading or color, while the topology of the paving mat 106 remains planar and flat. In some instances, the paving windrow 169 may result in geometric unevenness to the topology of the paving mat, for example, as may occur after a period of time during which the paving material 102 settles. The paving windrow 169 may be visibly or aesthetically displeasing and unattractive, or may complicate subsequent paving operations.

[0037] To reduce or eliminate the paving windrows 169, the lower material contacting surface 152 can include an additional geometric structural pattern in the form of a plurality of waves, curves, or undulations that vary the topology of the lower material contacting surface with respect to the vertical direction 135. For example, geometric structures comprising an undulating pattern 170, including a plurality of rising and following waves, can be situated rearward of the textured pattern 164 with respect to the travel direction 108. The rearward location of the undulating pattern 170 with respect to the textured pattern 164 results in physical interaction with the paving material exiting the plurality of channeling grooves 168 and forming the paving windrows 169. For example, the undulating pattern 170 can be located between the first and second side edges 160, 162 in the lateral direction 134 so as to laterally traverse the textured pattern 164 and in particular the plurality of channeling grooves 168 therein.

[0038] To structurally form the undulating pattern 170, one or more curved shapes such as arcuate ridges 172 can be included on the lower material contacting surface 152 of the screed plate 136. The arcuate ridges 172 can be linear, elongated structures that extend generally between the first and second side edges 160, 162 and that are aligned parallel with the rearward trailing edge 158. Each of the one or more arcuate ridges 172 can include a curved surface or ridge face 174 that protrudes outwards from the body of the screed plate 136 with respect to the vertical direction 135. For example, the arcuate ridges 172 may each includes an elongated ridge base 176 from which the curved ridge face 174 extends toward a ridge crest 178, indicated in dashed lines, that extend the lateral width of the screed plate 136 between the first and side edges 160, 162 and parallel to the rearward trailing edge 158.

[0039] Each arcuate ridge 172 can be straight and linear, extending in the lateral direction 134 with the ridge base 176 adjacent the lower material contacting surface 152 having dimensional width corresponding to the travel direction 108 from which the curved ridge face 174 curve and converges along the ridge crest 178, which may correspond to a singular linear line that is dimensionally smaller and thinner than the ridge base 176 in the travel direction 108. The distance between the ridge base 176 and the ridge crest 178 can correspond to and defines a ridge height 180 in the vertical direction 135. Moreover, when the undulating pattern 170 includes a plurality of parallel arcuate ridges 172 located adjacent each other as shown in FIG. 3, a corresponding plurality of undulating furrows 182 or troughs are defined within the gaps between the adjacent arcuate ridges 172. The plurality of undulating furrows 182 similarly extend in parallel alignment with the rearward trailing edge 158 of the screed plate 136 and the geometry of the undulating furrows 182 inversely corresponds with the shape of the curved ridge faces 174.

[0040] The plurality of arcuate ridges 172 may be lateral continuous in physical structure between the first and second side edges 160, 162 of the screed plate 136 such that the arcuate ridges and the corresponding undulating furrows 182 traverse the plurality of channeling grooves 168 in the textured pattern in the lateral direction 134. The undulating pattern 170 including arcuate ridges 172 and the undulating furrows 182 can be formed in the screed plate by casting, stamping, or machining.

[0041] The undulating pattern 170 functions to mechanically interact with and work the paving material passing behind the textured pattern 164 of the lower material contacting surface 152. For example, the rising and falling geometry associated with the alternating arrangement of the arcuate ridges 172 and the undulating furrows 182 applies a variable compacting force to the paving material during sliding contact with the lower material contacting surface 152. The alternating application and release of force to the paving material by the undulating pattern 170 briefly and repeatedly presses or squeezes then eases the forces applied to the paving material, resulting in relative displacement and dispersion of the aggregates, fines, and fluids within the paving materials. The physical, mechanical working of the paving material due to interaction with the undulating pattern 170 results in blending, amalgamation, and merging of the plurality of paving windrows 169 to make the stripes visibly less noticeable or to disappear.

[0042] For example, with reference to FIG. 2, the repeated application and release of compressive pressing forces due to physical interaction with the undulating pattern 170 can displace smaller granular fines and oils in the paving material 102 vertically upwards in the paving mat 106. The accumulation of such materials at the top surface of the paving mat 106 can blend and reduce the striped appearance or discoloring attributable to the paving windrows 169. Furthermore, the undulating pattern 170 can transmit forces deeply into the deposited paving material 102 to improve settling of the aggregates and the density of the paving mat 106.

[0043] Referring to FIG. 4, in an example, the undulating pattern 170 can include a plurality of arcuate ridges 172 that are arranged in successive lateral ridge rows 190. Each of the arcuate ridges 172 in the successive lateral ridge rows 190 can be parallel to the forward leading edge 156 and rearward trailing edge 158. In the illustrated example, the undulating pattern 170 can include a first lateral ridge row 192 that is located between the forward leading edge 156 and the rearward trailing edge 158 and that is proximate to the textured pattern 164. The undulating pattern 170 may also include a second lateral ridge row 194 located rearward of the first lateral ridge row 192 and a third lateral ridge row 196 that is contiguous with and that extends along the rearward trailing edge 158. The successive lateral ridge rows 190 may include fewer or more arcuate ridges 172 than as illustrated.

[0044] The dimensions and geometric shapes of each of the arcuate ridges 172 in successive lateral ridge rows 190 may differ and vary with respect to one another. For example, referring to FIG. 5, the arcuate ridges 172 in the first lateral ridge row 192 can be dimensionally larger, such as having a greater ridge height 182 and wider ridge base 176, than the arcuate ridges in the second and third lateral ridge rows 194, 196. Accordingly, the dimensional sizes of the arcuate ridges 172 gradually diminishes and decreases as the successive lateral ridge rows 190 progress rearward in the travel direction 108 toward the rearward trailing edge 158.

[0045] Because the ridge heights 182 of the arcuate ridges 172 reduces between the first, second, and third lateral ridge rows 192, 194, 196, the vertical dimension of the undulating pattern 170 in the vertical direction 135 likewise gradually decreases toward the rearward trailing edge 158 of the lower material contacting surface 152. The gradual reduction in height of the undulating pattern 170 can vary and alter the application and release of compressive or compacting forces directed to paving mat by the screed plate 136.

[0046] In an embodiment, the screed plate 136 may include a lateral leveling band 198 that is located immediately adjacent to the trailing edge 158. The lateral leveling band 198 can be characterized by the absence of any protruding elements 166 associated with the textured pattern 164 or arcuate ridges 172 associated with the undulating pattern 170 and thus has a flat, planar configuration. The lateral leveling band 198 can extend in the lateral direction 134 between the first and second side edges 160, 162 and can be longitudinally located between the undulating pattern 170 and the trailing edge 158 in the travel direction 108, and can occupy any suitable fraction of the longitudinal length of the screed plate 136 in the travel direction 108. The vertical flatness of the lateral leveling band 202 may function to further compact and smooth out the paving material moving underneath the screed plate 136.

[0047] The arrangement and configuration of the plurality of arcuate ridges 172 in the undulating pattern 170 may vary or differ. Referring to FIG. 6, in an example, an undulating pattern 200 can include one or more discontinuous arcuate ridges 202 that protrude from the lower material contacting surface 152 of the screed plate 136. The discontinuous arcuate ridges 202 may be curved in geometric shape and may define inversely corresponding undulating furrows 208 between the individual ridge lines. The discontinuous arcuate ridges 202 can be parallel to the rearward trailing edge 158 and located between the first and second side edges 160, 162, but may be discontinuous or segmented.

[0048] For example, each of the discontinuous arcuate ridges 202 can include a plurality of individual arcuate ridge segments 204 that are laterally separated by corresponding lateral ridge gaps 206. The arcuate ridge segments 204 of each arcuate ridge 202 can be laterally aligned with one another in the lateral direction 134 and thus parallel to the rearward trailing edge 158. The arcuate ridge segments 204 can have a curved or arcuate shape, including a curved exterior surface or curved ridge face 210 that curves in the vertical direction 135 between a segment base 212 and a segment crest 214. The curved shaped of the arcuate ridge segments 202 causes similar physical interaction with the paving material as described with respect to the continuous arcuate ridges 172 in FIGS. 3-5 above.

[0049] In a possible example and in comparison with the symmetrical arcuate ridges described above, the arcuate ridge segments 204 of the discontinuous ridges 202 may be asymmetrical in shape. As shown in detail, the asymmetrical arcuate ridge segments 204 can be characterized has having an increased or budged volume forward or rearward of the segment crest 214. The portion of the asymmetrical arcuate ridge segments 204 opposite of the segment crest 214 is thinner and forms a shaper or more tapered angle between the curved face 210 and the segment base 212. The curved ridge face 210 of the asymmetrical arcuate ridge segments 204 assumes the shape of an irregular curve.

[0050] In other examples, the discontinuous arcuate ridges 202 can be symmetrical in shape as described above. Relatedly, the continuous arcuate ridges 172 described in FIGS. 3-5 may be asymmetrical in shape.

[0051] The lateral ridge gaps 206 physically space apart and separate the plurality of ridge segments 204 in the lateral direction, and may reduce the material and weight of the screed plate 136. The lateral ridge gap 206 between the successive rows of arcuate ridges may align with each other or may be laterally staggered in alignment with each other in the travel direction 108. In an example, the discontinuous arcuate ridges 202 of the undulating pattern. 200 can also be physically separated and spaced apart from each other with respect to the travel direction 108. For example, in comparison with the continuous alignment of the successive lateral ridge rows 190 in FIG. 4, the discontinuous arcuate ridges 202 can be separated by longitudinal ridge gaps 216. The longitudinal ridge gaps 216 can have any suitable or appropriate spacing or dimensions to create a desired pitch between the plurality of discontinuous arcuate ridges 202 in the undulating pattern 200. The lateral ridge gaps 216 can increase the dimension and volume of the undulating furrows 208 in the undulating pattern 200. The longitudinal ridge gaps 216 can also be utilized to physically separate and space apart the continuous arcuate ridges 172 in FIGS. 3-5.

[0052] The arcuate ridge segments 204 can be located rearward of the channeling grooves 168 in the textured pattern 164 to interact with the paving windrows. For example, the arcuate ridge segments 204 can be aligned to traverse the channeling grooves 168 in the travel direction 108 so that the segments will physically encounter and interact with the plurality paving windrow formed by a trailing form the plurality of channeling grooves 168. In an example, the number of laterally aligned arcuate ridge segments 204 may correspond with the number of channeling grooves 168, although in other examples, the numbers may differ. In an example, to produce a smooth, planar upper topology on the paving mat, the rearward-most arcuate ridge 218 of the undulating pattern 200 can have a continuous extension between the first and second side edges 160, 162 of the screed plate 136. The continuous configuration of the rearward-most arcuate ridge 218 can function to reduce or eliminate visual distortions or effect of the lateral ridge gaps 206.INDUSTRIAL APPLICABILITY

[0053] Operation and effectiveness of the undulating pattern 170 on a screed plate 136 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 102 in the travel direction 108.

[0054] 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. The paving material 102 encounters and physical interacts with the textured pattern 164 that is contiguously adjacent to the forward leading edge 156 and a portion of the paving material may be directed into the plurality of channeling groove 168 due to contact with and displacement by the protruding elements 166.

[0055] For example, referring to FIG. 4 and as indicated by solid arrows 220, the paving material gathers and passes through the channeling grooves 168. The laterally shifting arrangement or zig-zag geometry of the channeling grooves 168 corresponding to and resulting from the geometric shapes of the protruding elements 166 may cause larger aggregates to homogenously mix and disperse in the mixture of paving material, but may result in paving windrows 169, indicated in dashed arrows, corresponding in location with the channeling grooves 168, to appear in the paving mat 106.

[0056] The distributed paving materials progress rearward toward the undulating pattern 170 due to relative movement of the screed plate 136 in the travel direction 108. The protruding geometry of the plurality of arcuate ridges 172 due to the ridge heights 180 applies compressive forces into the paving mat 106 in the vertical direction 135 as indicated by concentric circles representing forces arrows 222. Furthermore, the undulating furrows 182 located between the arcuate ridges 172 may relieve the applied forces as indicated by the circled crosses representing relief arrows 224. For example, the compressive forces associated with the force arrows 222 may be laterally aligned with ridge crests 178 and the relief arrow can be located within the undulating furrows 182 with respect to the travel direction 108, although it should be appreciated that the location of the force and relief arrows 222, 224 is intended for reference and the magnitude of the actual applied and released force with vary with the changing geometry of the undulating pattern 170. In the examples wherein the arcuate ridges extends substantially between the first and second lateral edges 160, 162 to traverse the channeling grooves 168, the application of forces extends across the plurality of paving windrows 169 with respect to the lateral direction 134.

[0057] The alternating and repeated application and release of force caused by the undulating pattern 170, indicated by force arrows 222 and relief arrows 224, functions to mechanical work and knead the paving material during sliding contact with the screed plate 136. As described above, the alternating pressure and release can cause or draw the finer particles and oils to proceed toward the upper surfaces of the paving mat, blending or obscuring the paving windows 169. The produced paving mat may have a more uniform and aesthetically pleasing appearance due to the physical interaction with and manipulation by the undulating pattern 170 on the screed plate 136.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

Examples

Embodiment Construction

[0014]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 m...

Claims

1. A screed plate for a screed assembly towed by a mobile paver comprising:a forward leading edge;a rearward trailing edge parallel to the forward leading edge;an upper frame attachment surface extending between the forward leading edge and the rearward trailing edge;a lower material contacting surface adapted to compact and compress paving material sliding underneath the screed plate, the lower material contacting surface including:a textured pattern contiguous to the leading edge and having a plurality of protruding elements and a plurality of channeling grooves located between the plurality of protruding elements, the plurality of channeling grooves extending from the leading edge toward the trailing edge; andan undulating pattern contiguous to the trailing edge and having one or more arcuate ridges traversing at least a portion of the plurality of channeling grooves and parallel to the trailing edge.

2. The screed plate of claim 1, wherein the undulating pattern includes at least one continuous arcuate ridge fully traversing the plurality of channeling grooves.

3. The screed plate of claim 2, wherein the undulating pattern includes at least one discontinuous arcuate ridge having a plurality of arcuate ridge segments that are laterally aligned.

4. The screed plate ofclaim 1, wherein the one or more arcuate ridges are arranged in successive lateral ridge rows parallel to the forward leading edge and the rearward trailing edge.

5. The screed plate of claim 4, wherein each of the successive lateral ridge rows includes a ridge base and a ridge crest both extending parallel to the forward leading edge and the rearward trailing edge.

6. The screed plate of claim 5, wherein each of the successive lateral ridge rows includes a ridge height between the ridge base and the ridge crest.

7. The screed plate of claim 6, wherein the successive lateral ridge rows include a first lateral ridge row adjacent to the rearward trailing edge and a second lateral ridge row located toward the forward leading edge with respect to the first ridge lateral row.

8. The screed plate of claim 7, wherein the row heights decrease between first lateral ridge row and the second lateral ridge row.

9. The screed plate of claim 8, wherein the successive lateral ridge rows includes a third lateral ridge row located toward the forward leading edge with respect to first ridge row and the second ridge row, the row height of the third lateral ridge row being larger than the ridge heights of the first lateral ridge row and the second lateral ridge row.

10. The screed plate of claim 1, wherein the at least one arcuate ridge has a symmetrically curved shape.

11. The screed plate of claim 1, wherein the at least one arcuate ridge has an asymmetrically curved shape.

12. The screed plate of claim 1, wherein the textured pattern and the undulating pattern are integrally cast with the screed plate.

13. The screed plat of claim 1, wherein the textured pattern and the undulating pattern are stamped into the screed plate.

14. A method of laying a paving mat comprising:receiving a paving material in a hopper of a mobile paver traveling longitudinally in a travel direction over a work surface;conveying the paving material from the hopper to an auger arranged laterally and perpendicular to the travel direction of the mobile paver;laterally distributing the paving material before a screed frame of a floating screed towed by the mobile paver;directing the paving material underneath a forward leading edge of a screed plate attached to an underside of the screed frame;compacting the paving material into a paving mat by sliding contact with a lower material contacting surface of the screed plate; anddirecting the paving material into a plurality of channeling grooves defined by a textured pattern on the screed plate to form a plurality of paving windrows corresponding to the plurality of channeling grooves; andvisibly reducing the plurality of windrows by sliding contact with an undulating pattern on the screed plate.

15. The method of claim 14, wherein the undulating pattern is defined by a plurality of arcuate ridges extending perpendicular to the travel direction and traversing the plurality of channeling grooves.

16. The method of claim 15, wherein the plurality of channeling grooves are generally aligned parallel to the travel direction.

17. The method of claim 16, wherein sliding contact with the undulating pattern causes sedimentation of the paving material directing aggregate fines and oils upwardly in a vertical direction perpendicular to the travel direction.

18. The method of claim 15, wherein the plurality of arcuate ridges are arranged in decreasing ridge heights with respect to the travel direction.

19. A screed plate for a screed assembly towed by a mobile paver comprising:a forward leading edge;a rearward trailing edge parallel to the forward leading edge;an upper attachment surface extending between the forward leading edge and the rearward trailing edge;a lower material contacting surface opposite the upper attachment surface, the lower material contacting surface including:a textured pattern located toward the forward leading edge and including a plurality of protruding elements and a plurality of channeling grooves located between the plurality of protruding elements; andan undulating pattern located toward the rearward trailing edge and including a plurality of arcuate ridges each having a ridge height and extending parallel to the rearward leading edge, the plurality of arcuate ridges arranged in successive lateral ridge rows with decreasing ridge heights toward the rearward trailing edge.

20. The screed plate of claim 19, wherein at least one of the plurality of arcuate ridges is a continuous arcuate ridge fully traversing the plurality of channeling grooves and at least one of the plurality of arcuate ridges is a discontinuous arcuate ridge having a plurality of arcuate ridge segments that are laterally aligned.

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