Screed assembly for paving machine

A screed assembly for a paving machine includes a main screed unit having a first section and a second section. A hinge assembly located above the main screed unit pivotally couples the first section with the second section. The first section and the second section rotate around a horizontal axis passing through the hinge assembly. A seal member located between the hinge assembly and the main screed unit covers a gap defined between the first section and the second section below the hinge assembly such that the seal member covers the gap and laterally extends beyond the gap above the first section and the second section. A pair of heating components attached to the first section and the second section heats the first section and the second section.

TECHNICAL FIELD

The present disclosure relates to a paving machine. More specifically, the present disclosure relates to a screed assembly for the paving machine.

BACKGROUND

A paving machine, such as an asphalt paver, is a self-propelled construction machine designed to receive, convey, distribute, profile and partially compact the asphalt material. The paving machine accepts asphalt material that is heated to an appropriate temperature for flow and even spreading into a receiving hopper at front of the paving machine. The asphalt material in the hopper is conveyed to rear of the paving machine with conveyors positioned at a bottom of the hopper.

The asphalt material conveyed from the hopper is distributed along width of an intended ribbon or mat by means of two opposing screws or spreading conveyors or augers, and a screed assembly profiles and compacts the asphalt material into a mat on the paving surface. The screed assembly may include two flat sections coupled together at a hinge so as to accommodate for a crowning motion of the paving machine in order to impart required slope to the paving surface. During the paving process, the screed assembly must be heated so that the hot paving material does not stick to a bottom surface of the screed assembly as the screed assembly passes over and compacts the mat.

As the paving material gets heated, viscosity of the paving material decreases and the paving material is able to flow easily and can be distributed on the paving surface effectively. If the screed assembly will not be heated to an adequate temperature, the hot paving material coming in contact with the screed assembly will get cooled, and as a result will stick to the screed assembly. The screed assembly has electrical heating elements that heat the screed assembly to the necessary temperature for paving. The heating elements may be attached to the screed assembly through mechanical fasteners and can be easily replaced after being worn out.

However, while the screed assembly passes over and compacts the mat, the hot paving material may enter the screed assembly through a gap between the two sections at the hinge. The hot asphalt may also stick to the mechanical fasteners holding the heating elements and may pose problems in easy removal of the heating elements for replacement later. It may also damage the heating elements in process of removal. Thus, an improved screed assembly is required to solve the aforementioned problem.

SUMMARY

In an aspect of the present disclosure, a screed assembly for a paving machine includes a main screed unit having a first section and a second section. The screed assembly includes a hinge assembly located above the main screed unit which pivotally couples the first section with the second section. The first section and the second section rotate around a horizontal axis passing through the hinge assembly. The screed assembly includes a seal member located between the hinge assembly and the main screed unit covering a gap defined between the first section and the second section below the hinge assembly, such that the seal member covers the gap and laterally extends beyond the gap above the first section and the second section. The screed assembly further includes a pair of heating components attached to the first section and the second section. The pair of heating components heats the first section and the second section.

In another aspect of the present disclosure, a paving machine is provided. The paving machine includes a tractor portion, a hopper adapted to receive a paving material, a conveyor, an auger and a screed assembly coupled to the tractor portion. The screed assembly includes a main screed unit having a first section and a second section. The screed assembly includes a hinge assembly located above the main screed unit which pivotally couples the first section with the second section. The first section and the second section rotate around a horizontal axis passing through the hinge assembly. The screed assembly includes a seal member located between the hinge assembly and the main screed unit covering a gap defined between the first section and the second section below the hinge assembly, such that the seal member covers the gap and laterally extends beyond the gap above the first section and the second section. The screed assembly further includes a pair of heating components attached to the first section and the second section. The pair of heating components heats the first section and the second section.

In yet another aspect of the present disclosure, a screed assembly for a paving machine includes a main screed unit having a first section and a second section. The screed assembly includes a hinge assembly located above the main screed unit which pivotally couples the first section with the second section. The first section and the second section rotate around a horizontal axis passing through the hinge assembly. The screed assembly includes a seal member located between the hinge assembly and the main screed unit covering a gap defined between the first section and the second section below the hinge assembly, such that the seal member covers the gap and laterally extends beyond the gap above the first section and the second section. The screed assembly includes a pair of heating components attached to the first section and the second section. The pair of heating components heats the first section and the second section. The screed assembly includes a wear bar coupled to the screed assembly at a first end of the gap. The wear bar restricts movement of the seal member along the gap towards the first end. The screed assembly further includes a wiper coupled to the screed assembly at a second end of the gap. The wiper restricts movement of the seal member along the gap towards the second end.

DETAILED DESCRIPTION

Wherever possible, the same reference numbers will be used throughout the drawings to refer to same or like parts. An exemplary embodiment of a paving machine100is shown generally inFIG. 1. The paving machine100, which may also be referred to as an asphalt paver, may be any machine used to distribute a layer of paving material on a surface of a roadway or other area. The paving machine100generally includes a tractor portion102including a power source104, such as an internal combustion engine. The paving machine100further includes ground engaging elements106, some or all of which may be powered by the power source104. Although, the ground engaging elements106are illustrated as wheels, it should be contemplated that the ground engaging elements106may as well be tracks, or a combination of wheel and tracks or any other known mechanism for propelling the paving machine100on a paving surface.

The paving machine100further includes an operator control station108. The operator control station108includes a steering wheel110and an operator seat112which is used by an operator to steer the paving machine100. The operator control station108may further include a user interface (not shown) having controls for various parts and subsystems of the paving machine100. The tractor portion102also supports various other components and systems, including a hopper, an auger (not shown) for receiving the paving material.

A conveyor (not shown) may also be supported on the tractor portion102and may convey the paving material received within the hopper to a screed assembly116, coupled with the paving machine100, such as via tow arms118, at a rear portion120of the tractor portion102. The screed assembly116distributes and provides partial compaction of the paving material into a mat on the desired paving surface. The screed assembly116of the paving machine100may also include additional components and systems, such as, for example, leveling arms, vibrators, tamper bars, sensors, and controllers, as are known to those skilled in the art.

The screed assembly116may generally include a main screed unit122, a first extendible frame portion124, and a second extendible frame portion126. Each of the first and second extendible frame portions124,126may be mounted on the main screed unit122and may be expandable sideways. The first and second extendible frame portions124,126may provide a walkway for an operator to have a better access to the surface being paved in order to assess quality of the paving operation or any other purpose for that matter. According to a specific example, the first and second extendible frame portions124,126may be hydraulically extendible, or expandable, using respective extension cylinders, as is known by those skilled in the art. In particular, the first and second extendible frame portions124,126may be expanded or shortened to effectively extend or shorten an adjustable paving width. According to some embodiments, each of the first and second extendible frame portions124,126may be independently adjustable. It should be noted that screed assembly116may alternately consist of a main screed with fixed width frames attached to the main screed for the purpose of attaining greater paving widths. The fixed width frames may act as extensions to the main screed. A combination of the main screed and the extensions may cover additional area on the surface being paved as compared to the main screed alone. Dimensions of the extensions may vary as per the application area of the paving machine100.

FIG. 2illustrates a portion of the main screed unit122. The main screed unit122includes a first section200and a second section202. The first section200and the second section202are coupled to each other with a hinge assembly204. For exemplary purposes, the hinge assembly204includes a first part206and a second part208. The first part206and the second part208of the hinge assembly204are complementary parts interconnected through a mechanical fastener210passing through both the first and second parts206,208such that the first and second parts206,208can rotate about the mechanical fastener210. Each of the first and second parts206,208are coupled to the first section200and the second section202of the main screed unit122respectively. Therefore, the first section200and the second202can also rotate about the hinge assembly204. The hinge assembly204may also be any other conventional type of hinge assembly which may be suitable to the need of the present disclosure.

The hinge assembly204is located above the main screed unit122. The first section200and the second section202can rotate relative to each other about an imaginary horizontal axis A-A′ passing through the hinge assembly204. The first section200and the second section202define a gap212between the first section200and the second section202below the hinge assembly204. The gap212has a first end214and a second end216and extends along the axis A-A′ between the first section200and the second section202of the main screed unit122. Dimensions of the gap212may vary as per machine configuration, paving requirements and make and model of the paving machine100for different applications.

FIG. 3shows further details of the screed assembly116without the hinge assembly204. It should be noted that the hinge assembly204has been taken out only for illustrative purposes to provide a better view of the screed assembly116, and the hinge assembly204is an integral part of the present disclosure. The screed assembly116functions to spread paving material distributed by the paving machine100onto the paving surface. In order to achieve optimum workability of the paving material, the temperature of the screed assembly116should be maintained within a predetermined temperature range. A set of heating components300maintains the temperature of the screed assembly116within the required temperature range as per the need of the application. Separate heating components300are coupled to the first section200and the second section202of the main screed unit122. The heating components300are coupled to the first section200and the second section202of the main screed unit122by any suitable mechanical fastening means.

In the illustrated embodiment, the heating components300are clamped with the first section200and the second section202of the main screed unit122through a bracket302and a fastener304. The fastener304may be any suitable mechanical fastener such as a bolt etc. It should be contemplated that any other fastening means may also be used as per the need of the application area of the paving machine100. The heating components300may be connected to a control system (not shown) which may regulate the temperature of the heating components300to control the temperature ranges of the main screed unit122. Various other types of heating elements may be used as well in place of the heating components300which may suit the need of the present disclosure.

It should be contemplated that the main screed unit122includes the first section200and the second section202coupled to each other through the hinge assembly204to allow a crowning/bending motion of the screed assembly116in order to impart required slope to the surface being paved. The crowning/bending motion refers to a bending of the first section200and the second section202of the main screed unit122about the axis A-A′ so that the first section200and the second section202impart a slope and maintain contact with the surface being paved. Structure of the main screed unit122as a combination of the first section200and the second section202instead of a single screed allows the heating components300to remain in contact with the first section200and the second section202of the main screed unit122at all times irrespective of the crowning/bending motion of the screed assembly116.

The screed assembly116further includes a seal member306. The seal member306is located below the hinge assembly204. The seal member306covers the gap212between the first section200and the second section202and laterally extends beyond the gap212above the first section200and the second section202.FIG. 4illustrates the seal member306located below the hinge assembly204and covering the gap212between the first section200and the second section202of the main screed unit122. The seal member306is a U-shaped plate extending from the first end214to the second end216of the gap212. The seal member306covers the gap212and inhibits any debris, or dust or asphalt ingress through the gap212into the screed assembly116. The seal member306is made of a flexible material for e.g. steel or any other material which may be suitable as per the scope of the present disclosure.

As the seal member306is U-shaped, sideways movement of the seal member306is restricted, and the seal member306does not move an appreciable distance laterally and stays in place. Longitudinal movement of the seal member306is restricted on the first end214of the gap212by a wiper400. The wiper400is coupled to the screed assembly116towards the first end214of the gap212.

As there is the gap212between the first section200and the second section202of the main screed unit122, it may be possible that a portion of asphalt mat which is coming below the gap212may not get compressed by same amount of force as compared to a portion of the asphalt mat coming below the first section200and the second section202of the main screed unit122. This may lead to formation of an extrusion in middle of the asphalt mat being paved. The wiper400is provided to level this extrusion as the screed assembly116moves along the paving surface. The wiper400keeps the seal member306in place and ensures that there is no movement of the seal member306towards the first end214of the gap212. An imaginary plane B-B′ passing through the hinge assembly116as well as the gap212between the first section200and the second section202of the main screed unit122divides the screed assembly116in two symmetrical parts. The plane B-B′ is perpendicular to the paving surface.

FIG. 5shows a sectional view of the screed assembly116taken along the plane B-B′ ofFIG. 4. As illustrated the seal member306extends from the first end214to the second end216of the gap212. Movement of the seal member306along the gap212is restricted at the second end216of the gap212by a wear bar500. The wear bar500is coupled to the screed assembly116towards the second end216of the gap212through any mechanical fastening means suitable to the scope of the present disclosure. The wear bar500keeps the seal member306in place towards the second end216of the gap212and ensures that there is no movement of the seal member306towards the second end216of the gap212. Restriction of the sideways movement of the seal member306due to the U-shape of the seal member306, and restriction of the movement of the seal member306along the gap212at the first end214by the wiper400and at the second end216by the wear bar500ensures that the gap212is covered at all times.

INDUSTRIAL APPLICABILITY

The present disclosure provides an improved arrangement for the screed assembly116of the paving machine100. The screed assembly116includes the main screed unit122. The main screed unit122includes the first section200and the second section202pivotally coupled to each other through the hinge assembly204. The gap212is defined between the first section200and the second section202of the main screed unit122below the hinge assembly204. The seal member306is located below the hinge assembly204. The seal member306covers the gap212between the first section200and the second section202and laterally extends beyond the gap212above the first section200and the second section202. The seal member306inhibits ingress of any dust, debris, concrete, or asphalt material from the gap212in to the screed assembly116.

As heated asphalt etc. can no longer enter the screed assembly116through the gap212, it facilitates easy removal of the heating components300. Removable or replaceable heating components300can be used without facing any problems while replacement. Further, any damages to various parts of the screed assembly116due to coming in contact with heated asphalt, debris, dust etc. are avoided. Maintenance and service procedures of the screed assembly116can be carried out more easily as compared to the prior art arrangements. Also, frequent downtimes due to any such problems are avoided and the heating components300can be periodically serviced or replaced to ensure that the screed assembly116operates within acceptable temperature ranges.

The seal member306stays in place and does not move laterally or along the gap212. The movement of the seal member306in the lateral direction is restricted by the U-shape of the seal member306. The wiper400and the wear bar500restrict the movement of the seal member306along the gap212towards the first end214and the second end216respectively. Due to the shape and placement of the seal member306in the screed assembly116, the seal member306does not need any additional coupling arrangements or fasteners etc. to keep the seal member306fixed in place. This provides for easy replacement of the seal member306, once the seal member306has worn out. Further, as the seal member306is made of a flexible material, for e.g. steel, the seal member306may adjust against any vibrations etc. which may arise due to the operation of the paving machine100or otherwise. Also, the seal member306fits in the designated place effectively and covers the gap212efficiently against any material ingress.