WO2014204743A1

WO2014204743A1 - Screed frame and plate

Info

Publication number: WO2014204743A1
Application number: PCT/US2014/041885
Authority: WO
Inventors: Jason W. Kopacz; Timothy L. Wehrenberg
Original assignee: Caterpillar Paving Products Inc.
Priority date: 2013-06-21
Filing date: 2014-06-11
Publication date: 2014-12-24
Also published as: US20140377003A1

Abstract

A screed includes a frame and a plate. The frame includes a bottom surface and a plurality of mounting members. The plurality of the mounting members project from the bottom surface. At least one of the plurality of the mounting members is longitudinally and transversely offset relative to the other mounting members. Further, the plate is coupled to the frame by the plurality of the mounting members.

Description

SCREED FRAME AND PLATE

Technical Field

The present disclosure relates to a screed, and more particularly to a screed frame and a plate.

Background

A paving machine includes a screed for laying paving material on a road surface. The screed includes at least one screed plate that may level and compact the paving material. Weight of the screed facilitates initial compaction of the paving material. The screed plate may be heated to further facilitate the paving operation. Heating the screed plate may assist in improved flow of the paving material and reduce adhesion of the paving material to the screed plate. Inadequate or uneven heating of the screed plate may result in premature hardening of the paving material, resulting in buildup of the paving material and undesired drag.

US Pat. No. 6,318,928 discloses a paving machine that employs an electrically heated screed assembly to uniformly heat a screed plate of the machine. Uniform heating is achieved by inserting a thermally conductive plate between electrical heating elements and the screed plate. An insulation layer may be provided above the heating elements to direct the heat downward into the thermally conductive plate. The heat spreads relatively uniformly throughout the thermally conductive plate, thereby uniformly heating the screed plate. A clamping mechanism is also provided that, when tightened, provides a compressive force, thereby holding the assembly in place. When released, the pressure is alleviated, thus permitting a heating element to be removed for repair or replacement without the need to remove the screed plate. Summary

In one aspect, the present disclosure provides a screed including a frame and a plate. The frame includes a bottom surface and a plurality of mounting members. The plurality of the mounting members project from the bottom surface. At least one of the plurality of the mounting members is longitudinally and transversely offset relative to the other mounting member. Further, the plate is coupled to the frame by the mounting members.

In another aspect, the present disclosure provides a paving machine including a tractor and a screed coupled to the tractor. The screed includes a frame and a plate. The frame includes a bottom surface and a plurality of mounting members. The plurality of the mounting members project from the bottom surface. At least one of the plurality of the mounting members is longitudinally and transversely offset relative to the other mounting member. Further, the plate is coupled to the frame by the mounting members.

In yet another aspect, the present disclosure provides a screed including a frame and a plate. The frame includes a bottom surface and a plurality of mounting members projecting from the bottom surface. The plate is coupled to the frame by the coupling members. The plate includes a heating element. Further, the plurality of the mounting members are arranged to provide a substantially uniform heat distribution across the plate.

Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.

Brief Description of the Drawings

FIG. 1 illustrates a side view of a paving machine having a screed;

FIG. 2 illustrates a perspective view of frames of the screed; FIG. 3 illustrates a bottom perspective view of the first extender screed;

FIG. 4 illustrates a partly assembled right perspective view of the first extender screed;

FIG. 5 illustrates an assembled left side view of the first extender screed of FIG. 4; and FIG. 6 illustrates a bottom view of a first extender plate support portion.

Detailed Description

The present disclosure describes a screed of a paving machine. FIG. 1 illustrates a side view of a paving machine 100, according to an embodiment of the present disclosure. The paving machine 100 includes a tractor 102 and a screed 104 disposed to the rear of the tractor 102. The screed 104 is flexibly coupled to the tractor 102 by tow arms 106 (only one illustrated in FIG. 1) and follows the tractor 102. However, the screed 104 may be mounted in front of the tractor 102. Further, tractor 102 includes a propulsion arrangement 108. The propulsion arrangement 108, as illustrated in FIG. 1, may include wheels. Alternatively, the propulsion arrangement may include tracks. Further, the paving machine 100 is driven by a prime mover 110, for example, an internal combustion engine. In an embodiment, of the present disclosure, the prime mover 110 may also drive an electric generator 112. The electric generator 112 may be an AC or a DC generator. The tractor 102 further includes a hopper 114 that receives paving material from a dump truck.

In an embodiment of the present disclosure, the screed 104 includes a main screed 116, a first extender screed 118A and a second extender screed (shown in FIG. 2). In an embodiment of the present disclosure, the main screed 116 includes a first main frame and a second main frame. Further, the first extender screed 118A and the second extender screed includes a first extender frame and a second extender frame, respectively. Various details of the first and the second main frames, and the first and the second extender frames will be described henceforth with reference to FIG. 2.

FIG. 2 illustrates a perspective view of the first and the second main frames 202A, 202B, and the first and the second extender frames 204A, 204B. The first and the second main frames 202A, 202B are part of the main screed 116. Further, the first and the second extender frames 204A, 204B are part of the first and the second extender screeds 1 18 A, 118B, respectively. The first extender frame 204A includes a first upper part 206A and a first lower part 208A. Further, the second extender frame 204B includes a second upper part 206B and a second lower part 208B. As illustrated in FIG. 2, the first and the second main frames 202A, 202B include first and second main plate support portions 21 OA, 21 OB, respectively. A first main screed plate 212A and a second main screed plate 212B are coupled to the support portion 21 OA and the support portion 21 OB, respectively, by fasteners 214. Further, the first and the second lower parts 208A, 208B include first and second extender plate support portions 216A, 216B, respectively. A first extender screed plate 218A and a second extender screed plate 218B are coupled to the support portions 216A, 216B, respectively, by fasteners 214.

In an embodiment of the present disclosure, the first and the second main frames 202A, 202B may be pivotable about a main pivot axis "P". The main pivot axis "P" may be located at a center line "L" between the first and the second main frames 202A, 202B. Therefore, the plates 212A and 212B may also be pivotable about the pivot axis "P". In another embodiment of the present disclosure, the first and the second extender frames 204A, 204B may be extendable and retractable relative to the first and the second main frames 202A, 202B, respectively, along a sliding direction "S". Therefore, the plates 218A and 218B may also be retractable and extendable relative to the plates 212A and 212B, respectively, along the sliding direction "S". Further, in an embodiment, the first and the second extender frames 204A, 204B may be pivotable relative to the first and the second main frames 202A, 202B, respectively, about a slope axis "D". Therefore, the plates 218A and 218B may also be pivotable relative to the plates 212A and 212B, respectively, about the slope axis "D". In another embodiment, the first and the second lower parts 208A, 208B may be adjustable relative to the first and the second upper parts 206A, 206B, respectively, in a height direction "H". Therefore, the plates 218A and 218B may also be adjustable relative to the plates 212A and 212B, respectively, along the height direction "H".

The adjustments of the plates 212A and 212B, and the plates 218A and 218B, as described above, may enable the screed 104 (illustrated in FIG. 1) to pave differently shaped surfaces. Further, the main pivot axis "P", the sliding direction "S", the slope axis "D" and the height direction "H", as described above, are purely exemplary in nature, and the screed 104 may be adjustable in various other manners within the scope of the present disclosure. Various details of the first extender frame 204A will be described hereinafter with reference to FIGS. 3-7. However, the details of the first extender frame 204A may be applied in the first and second main frames 202A, 202B, and the second extender frame 204B.

FIG. 3 illustrates a bottom perspective view of the first extender frame 204A according to an embodiment of the present disclosure. Various components hidden by the plate 218 A may be illustrated by dotted lines. The support portion 216A includes a set of first mounting members 302 located proximate a first longitudinal end 304, and a set of second mounting members 306 located proximate a second longitudinal end 308. Each of the first mounting members 302 includes a lower portion 309 and an upper portion 310. A first opening 312 extends from the lower portion 309 to the upper portion 310. Further, the lower portion 309 of each of the first mounting member 302 is in contact with the plate 218A. As illustrated in FIG. 3, the lower portion 309 is substantially cuboidal. Each of the second mounting members 306 includes a second opening 314. Each of the second mounting members 306 is in contact with the plate 218A. Further, each of the second mounting members 306 is substantially cylindrical. The plate 218A includes multiple fastening apertures 402 that may align with the first and the second openings 312, 314 of the first and the second mounting members 302, 306, respectively. The fasteners 214 pass through the fastening apertures 402, and the respective first and second openings 312 and 314. Further, the first and the second openings 312 and 314 may be substantially cylindrical. The fastening member 214 may be threaded studs and the fastening apertures 402 may have corresponding threads to receive the fastening members 214. In an alternative embodiment, the fastening members 214 may be integral with the plate 218A.

In an embodiment, the plate 218A includes a first heating element 404 and a second heating element 406. The first and the second heating elements 404, 406 may be resistive heating elements. The first and the second heating elements 404, 406 may be supplied with electric power by the electric generator 112 (illustrated in FIG. 1). A first support member 408 may be disposed on the first heating element 404. The first support member 408 includes a central portion 410 and multiple branch portions 412 extending on both sides of the central portion 410. The branch portions 412 engage with the first heating element 404. Multiple heating element fasteners 418 couple the first support member 408 to the support portion 216A of the first extender frame 204A. Multiple second support members 420 may secure the second heating element 406 to the plate 218A. Each second support member 420 may include a channel (not shown). The fasteners 214 pass through the fastening apertures 402 of the plate 218A, the corresponding channels of the second support members 420, and apertures (not illustrated) of the support portion 216A, thereby coupling the second support members 420 to the plate 218A and the support portion 216A. An end support member 424 may also secure the second heating element 406 to the plate 218A. The end support member 424 may include a channel (not shown). In an embodiment, the end support member 424 is substantially cylindrical. The fastener 214 passes through the fastening aperture 402 of the plate 218A, and the channel of the end support member, thereby coupling the end support member 424 to the plate 218 A.

FIGS. 4 and 5 illustrate detailed views of the first extender frame

204, according to an embodiment of the present disclosure. A lower surface 315 of each of the lower portions 309 may contact an upper surface 428 of the plate 218A. Further, a lower surface 317 of each of the second mounting members 306 may contact the upper surface 428 of the plate 218A. The support portion 216A includes an upper transverse member 316 and a lower transverse member 318. In an embodiment, the upper and the lower transverse members 316, 318 may be substantially planar. In an embodiment, the second mounting members 306 and the lower portions 309 of the first mounting members 302 project from a bottom surface 319 of the lower transverse member 318. Further, the first longitudinal end 304 includes a first end wall 320 and a curved portion 322. The curved portion 322 connects the first end wall 320 to the upper transverse member 316. Further, the second longitudinal end 308 includes a second end wall 324. The first and the second end walls 320, 324 are connected to the lower transverse member 318. Further, lower surfaces 326 and 328 of the first and the second end walls 320, 324, respectively, contact the upper surface 428 of the plate 218A. The first and the second end walls 320, 324 may result in a clearance 502 between the bottom surface 319 of the lower transverse member 318 and upper surface 428 of the plate 218A. Further, the lower portion 309 of the each of the first mounting members 302 may protrude transversely from the second end wall 324 by a distance 503. The lower transverse member 318 includes first apertures 332 that receive the second mounting members 306 and the second support members 420. The upper transverse member 316 may include corresponding apertures so that the second mounting members 306 and the second support member 420 project beyond the upper transverse member 316. Further, nuts 504 and washers 506 couple the fasteners 214 to the first mounting members 302, the second mounting members 306, the second support members 420, and the end support member 424.

Each of the second support members 420 includes an elongate portion 430 and a retaining portion 432. The elongate portion 430 passes through the upper and the lower transverse members 316, 318. The retaining portion 432 contacts the second heating element 406. The retaining portions 432 may secure the second heating element 406 to the plate 218A. The elongate portion 430 is substantially cylindrical, while the retaining portion 432 is a disc. Further, the fastener 214, passing through the channel of the end support member 424, may protrude though the first aperture 332 of the lower transverse member 318. In an embodiment, additional apertures (not illustrated) may be provided in the upper and the lower transverse members 316, 318. The additional apertures may receive fasteners 214 that pass through corresponding apertures (not shown) of the plate 218A.

Further, a curved end 429 of each of the branch portions 412 engage with the first heating element 404. The curved ends 429 may retain the first heating element 404 on the plate 218A. Further, the heating element fasteners 418 also pass through second apertures 334 of the lower transverse member 318. The heating element fasteners 418 also pass through the upper transverse member 316 and locking members 436 (only one illustrated in FIG. 5). The locking members 436 may secure the heating element fasteners 418 to the support portion 216A. Further, a clamp 434 is attached to the end support member 424. The clamp 434 extends from the end support member 424 and contacts the second heating element 406. The clamp 434 may retain the second heating element 406 to the plate 218A. Electrical leads 438 are connected to the first and the second heating elements 404, 406. The electric leads 438 may transmit electric energy to the first and the second heating elements 404, 406. FIG. 6 illustrates a bottom view of the support portion 216A. The first and the second longitudinal ends 304, 308 may have a length 507. Further, the lower surface 326 of the first end wall 320 may have a width 508. The lower surface 328 of the second end wall 324 may have a width 509. In an embodiment, the length 507 may lie in a range from about 0.5 meters to 1.75 meters. Further, the widths 508 and 509 of the lower surfaces 326, 328, respectively, may lie in a range from about 6 mm to 16 mm. The lower portion 309 of each of the first mounting members 302 may have a width 510 and a length 512. Each of the first openings 312 may have a diameter 514. In an embodiment, the width 10 of the lower portion 309 may lie in a range from about 30 mm to 60 mm. Further, the length 512 of the lower portion may lie in a range from about 30 meters to 60 meters. The diameter 514 of the first opening 312 may lie in a range from about 13 mm to 30 mm. A first longitudinal offset 515 between two adjacent first mounting members 302 may lie in a range from about 200 mm to 300 mm. Each of the lower portions 309 are also received within a third aperture 336 of the lower transverse member 318. In an embodiment, the lower portions 309 may be attached to walls of the third apertures 336 and/or portions of the first longitudinal end 304. The lower portions 309 may also be attached to walls of corresponding apertures (not shown) of the upper transverse member 316 (illustrated in FIG. 5). In an alternate embodiment, the lower portions 309 may be integral with the support portion 216A. Further, a clearance may be provided between the fasteners 214 (illustrated in FIGS. 3-5) and the first openings 312.

As illustrated in FIG. 6, the second opening 314 of each of the second mounting members 306 may have a diameter 516. Further, each second mounting member 306 may have an outer diameter 518. In an embodiment, the diameter 516 of the second opening 314 may lie in a range from about 15 mm to 25 mm. Further, the outer diameter 518 of each second mounting member 306 may lie in a range from about 25 mm to 40 mm. A second longitudinal offset 520 between adjacent second mounting members 306 may lie in a range from about 200 mm to 300 mm. Further, a transverse offset 522 between each of the first mounting members 302 and each of the second mounting members 306 may lie in a range from about 200 mm to 450 mm. The transverse offset 522 may be substantially perpendicular to the first and the second longitudinal offsets 515, 520. In an embodiment, the first longitudinal offset 515 may be substantially equal to the second longitudinal offset 520. Each of the second mounting members 306 are received within the first aperture 332 of the lower transverse member 318. In an embodiment, the second mounting members 306 may be attached to walls of the first aperture 332. The second mounting members 306 may also be attached to walls of corresponding apertures (not shown) of the upper transverse member 316 (illustrated in FIG. 5). In an alternate embodiment, the second mounting members 306 may be integral with the support portion 216A.

The various dimensional ranges, as described above, are purely exemplary in nature, and various components of the support portion 216A may have any other dimensions within the scope of the present disclosure. Further, the first and second mounting members 302, 306 may have alternative shapes, for example, but not limited to, polyhedral, elliptic cylinder, or the like. In the embodiment, as illustrated in FIGS. 3 and 6, the support portion 216A includes six first mounting members 302 and six second mounting members 306. However, there may be any number of the first and the second mounting members 302, 306. As illustrated in FIGS. 5 and 6, the first and the second mounting member s 302, 306 are arranged substantially linearly and parallel to the first and the second longitudinal ends 304, 308, respectively. Thus, each of the first mounting members 302 are longitudinally offset relative to each other. Similarly, each of the second mounting members 308 are longitudinally offset relative to each other. However, in various other embodiments, the first and/or the second mounting members 302, 306 may be arranged in a zigzag manner (not shown). For example, a first set of the first mounting members 302 may be arranged proximal to the first longitudinal end 304 along a first line that is inclined to the first longitudinal end 304 at a first angle. Further, a second set of the first mounting members 302 may be arranged distal to the first longitudinal end 304 along a second line that is inclined to the first longitudinal end 304 at a second angle. Thus, the first set of the first mounting members 302 may be both longitudinally and transversely offset relative to the second set of the first mounting members 302.

Various embodiments of the present disclosure were described with reference to the first extender frame 204A in FIGS. 3-6. However, it may be apparent to a person ordinarily skilled in the art that the various embodiments may be present in the first and the second main frames 202A, 202B, and the second extender frame 204B. For example, the first and the second mounting members 302, 306 may be provided in the support portions 210A, 210B, and 216B of the first and the second main frames 202A, 202B, and the second extender frame 204B, respectively. Further, the plates 212A, 212B and 218B may include one or more heating elements. In an embodiment, the plates 212A, 212B and 218B may be coupled to the support portions 210A, 210B and 216B, respectively, in a manner that is substantially similar to in case of the plate 218A and the support portion 216A.

In an embodiment, bolt-on extensions (not shown) may be used in conjunction with the screed 104. The bolt-on extensions may use similar first and second mounting for providing an interface between their respective frames and plates. The bolt-on extensions may be of various lengths in order to provide variable paving length.

Industrial Applicability

The present disclosure relates to the paving machine 100 which includes the tractor 102 and the screed 104. The paving machine 100 includes a hopper 114 configured to receive paving material from a dump truck. A conveyor (not illustrated) of the paving machine may transfer the paving material from the hopper for discharge onto a roadbed. One or more augers (not illustrated) may spread the paving material. The plates 212A, 212B, 218A and 218B of the screed 104 may level and compact the paving material. The operation of the screed 104 is described henceforth with respect to the first extender frame 204A.

The plate 218A of the first extender frame 204A may be heated by the first and the second heating elements 404, 406 to facilitate the compaction of the paving material. In case of one or more continuous interfaces between the plate 218A and the support portion 216A, there may be substantially heat loss from the plate 218A to the first extender frame 204A. This may result in a nonuniform heat distribution with the continuous interfaces of the plate 218A being the substantially cooler than the rest of the plate 218A. Heat loss from the four corners (not shown) of the plate 218A may be maximum resulting in the corners not being heated sufficiently. A paving operation may therefore be unsatisfactory. Further, energy efficiency may be low.

According to an embodiment the present disclosure, the support portion 216A contacts the plate 218A at discrete portions, namely, the lower surfaces 326 and 328 of the first and the second end walls 320, 322, respectively, and the lower surfaces 315 and 317 of the lower portions 309 and the second mounting members 306, respectively. The widths 508 and 509 of the first and the second end walls 320, 324 may be small enough to prevent any substantial heat loss from the plate 218A. Further, the lower surfaces 315 and 317 of the lower portions 309 and the second mounting members 306, respectively, may provide discrete interfaces between the plate 218A and the support portion 216A. There, an area of contact between the plate 218A and the support portion 216A may be substantially reduced compared to one or more continuous interfaces with widths comparable with the width 510 of each lower portion 309 or the outer diameter 518 of each second mounting member 308. Consequently, heat loss from the plate 218A to the support portion 216A may be substantially reduced. The clearance 502 (illustrated in FIG. 5) between the lower transverse member 318 and the plate 218A may further reduce heat loss from the plate 218A to the support portion 216A. Reduced heat loss may result in a more uniform heat distribution across the plate 218A. In particular, discrete interfaces between the plate 218A and the support portion 216A may reduce heat loss from the corners of the plate 218A. Thus, the corners of the plate 218A may receive adequate heat, thereby resulting in a more uniform heat distribution across the plate 218A. Therefore, the plate 218A may achieve a target temperature, which may be required for paving, at a faster rate with a more even heat distribution. This may improve a paving operation and/or energy efficiency of the screed 104.

During a paving operation, various forces may act on the plate 218A, such as, torsion, gravity, pull forces, or the like. These forces may tend to displace the plate 218A relative to the support portion 216A, that may have a detrimental effect on paving quality. Adjustment of the plate 218A along the sliding direction "S", about the slope axis "D", and along the height direction "H" may further tend to displace the plate 218A relative to the support portion 216A. According to an embodiment of the present disclosure, the width 510 of each of the six lower portions 309, and/or the outer diameter 518 of each of the six mounting members 308 may ensure a rigid coupling of the plate 218A to the support portion 216A. The lower surfaces 326 and 328 of the first and the second end walls 320, 324, respectively, may further provide stability of the plate 218 A. Thus, the plate 218 A may provide a desired paving quality.

The various features of the first extender frame 204A, as described above, may be applicable to the first and the second main frames 202A, 202B, and the second extender frame 204B. Therefore, in an embodiment of the present disclosure, heat loss from the plates 212A, 212B and 218B may have a substantially uniform heat distribution. Further, the plates 212A, 212B and 218B may be rigidly coupled to the support portions 21 OA, 21 OB and 216B, respectively.

Although the embodiments of this disclosure as described herein may be incorporated without departing from the scope of the following claims, it will be apparent to those skilled in the art that various modifications and variations can be made. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure. It is intended that the specification and examples be considered as exemplary only, with a true scope being indicated by the following claims and their equivalents.

Claims

1. A paving machine comprising:

a tractor;

a screed coupled to the tractor, the screed comprising:

a frame comprising a bottom surface and a plurality of mounting members; and

a plate;

wherein the plurality of the mounting members project from the bottom surface, at least one of the plurality of the mounting members being longitudinally and transversely offset relative to the other mounting members; and

wherein the plate is coupled to the frame by the mounting members.

2. The paving machine of claim 1, wherein each of the plurality of the mounting members comprises an opening, the opening configured to receive a fastener.

3. The paving machine of claim 2, wherein the plate comprises a fastening aperture, the fastening aperture configured to receive the fastener.

4. The paving machine of claim 1, wherein the plurality of the mounting members comprises a set of first mounting members and a set of second mounting members, the first mounting members located proximate a first longitudinal edge of the bottom surface, and the second mounting members located proximate a second longitudinal edge of the bottom surface.

5. The paving machine of claim 4, wherein each of the first mounting members are longitudinally offset relative to each other, wherein each of the second mounting members are longitudinally offset relative to each other, and wherein each of the first mounting members are transversely offset relative to each of the second mounting members.

6. The paving machine of claim 1, wherein the frame further comprises a first end wall and a second wall projecting from the bottom surface of the frame, the first end wall and the second end wall configured to contact the plate.

7. The paving machine of claim 1, wherein the plate further comprises a heating element.

8. A screed comprising:

a frame comprising a bottom surface and a plurality of mounting members projecting from the bottom surface; and

a plate coupled to the frame by the plurality of the mounting members, the plate comprising a heating element;

wherein the plurality of the mounting members being arranged to provide a substantially uniform heat distribution across the plate.

9. The screed of claim 8, wherein each of the plurality of the mounting member comprises a opening, the opening configured to receive a fastener.

10. The screed of claim 9, wherein the plate comprises a fastening aperture, the fastening aperture configured to receive the fastener.

11. The screed of claim 8, wherein the plurality of the mounting members comprises a set of first mounting members and a set of second mounting members, the first mounting members located proximate a first longitudinal edge of the bottom surface, and the second mounting members located proximate a second longitudinal edge of the bottom surface.

12. The screed of claim 11 , wherein each of the first mounting members are longitudinally offset relative to each other, wherein each of the second mounting members are longitudinally offset relative to each other, and wherein each of the first mounting members are transversely offset relative to each of the second mounting members.

13. The screed of claim 8, wherein the frame further comprises a first end wall and a second wall projecting from the bottom surface of the frame, the first end wall and the second end wall configured to contact the plate.