The present application relates generally to apparatuses, methods and systems that retain a heating element cover and enable the ease of replacement and installation of screed heating elements positioned under the heating element cover in working machines.
Pavers or paving machines are working machines used in an asphalt paving process to create a new road surface. Such pavers assist in pouring and spreading paving material to form a new roadway surface or mat. With asphalt pavers, an aggregate filled bituminous mixture that comprises the paving material is spread while hot and is then compacted so that a hardened pavement surface is formed upon cooling. Pavers typically utilize a heavy assembly termed a “screed” that is drawn behind the paving machine. The screed assembly includes a replaceable screed plate to spread a smooth even layer of paving material on the prepared roadbed. The weight and/or a vibration of the screed assembly aids in compressing the paving material and performing initial compaction of the paving material layer.
To facilitate laying of the paving material, the screed plate is typically heated, to a temperature in the range of about 82° to 171° C. (180° to 340° F.). Heating the screed plate assists the paving material in flowing under the screed plate and reduces adhesion of the paving material to the screed plate. If the screed plate is not adequately heated, the bituminous mixture contacting the bottom of the screed plate begins to harden, resulting in buildup of paving material and excessive drag.
Some screeds such as those of U.S. Pat. No. 10,017,905 utilize a compression bolt assembly. However, the compression bolt assembly as disclosed in U.S. Pat. No. 10,017,905 is configured to be inserted through and upper portion of the screed plate and through a hole in a primary bolt. The compression bolt assembly cooperates with the upper portion of the screed plate to apply a desired compression force via direct contact to the heating element on a lower screed plate. The compression bolt assembly of U.S. Pat. No. 10,017,905 fails to contemplate (and therefore address) ease of replacement and installation of screed heating elements and/or the promotion of even heat distribution. For example, the arrangement of U.S. Pat. No. 10,017,905 contemplates the use of the upper portion of the screed plate and the compression bolt assembly with multiple components of the compression bolt assembly inaccessible or difficult to reach under the upper portion of the screed plate. Furthermore, the compression bolt assembly must be removed for the upper portion of the screed plate to be removed to access the screed heating elements.
In one example, a screed assembly for use with a paving machine is disclosed. The screed assembly can optionally comprise: a screed plate; a heating assembly having a heating element positioned on the screed plate; a heating element cover positioned on or adjacent the heating element; a screed frame releasably coupled to the screed plate and having one or more openings therein; and a plurality of compression spring assemblies connected to the screed frame and connected to the heating element cover, wherein each of the plurality of compression spring assemblies includes at least a bolt, a spring and a spring adjustment nut that together are configured to exert a desired force on the heating element cover, wherein the plurality of compression spring assemblies are accessible through the one or more openings of the screed frame and the bolt is moveable relative to the screed frame to adjust a position of the heating element cover relative to the heating element for facilitating removal of the heating element
In another example, a method of assembling a screed assembly for use with a paving machine is disclosed. The method can optionally include positioning a heating element between a screed plate and a heating element cover; connecting at least the screed plate to a screed frame of the screed assembly; connecting the heating element cover to the screed frame with a plurality of compression spring assemblies; and setting a desired force exerted on the heating element cover by the plurality of compression spring assemblies.
In another example, a paving system for laying an asphalt paving material is disclosed. The system can optionally include a paving machine; and a screed assembly configured to be removably connected to the paving machine. The screed assembly can optionally comprise: a screed plate; a heating element cover; a heating assembly including a heating element insertable between the screed plate and the heating element cover; a screed frame configured to be spaced from the screed plate and removably coupled thereto, wherein the screed frame includes one or more openings therein; and a plurality of compression spring assemblies configured to be connected to the screed frame and configured to be connected to the heating element cover, wherein the plurality of compression spring assemblies are configured to set a desired position between the heating element cover and the heating element, and wherein the plurality of compression spring assemblies reside in a space in the screed frame and are accessible through the one or more openings of the screed frame to adjust the desired position.
Loose paving material 30 can be deposited onto a work surface 32 via a dump truck or other suitable means. The paving machine 10 can include means for moving the loose paving material 30 into the hopper 26, such as the elevator 28. The paving material 30 can be asphalt, aggregate materials or concrete. In various embodiments, the paving material 30 can be deposited directly into the hopper 26 of the paving machine 10. The paving machine 10 can travel in direction D, while the conveyor system 24 can move paving material in the opposite direction from the hopper 26 to the auger system 16. Various methods and machines such as a dump truck, material transfer vehicle, etc. can be employed to get the paving material 30 into the hopper 26.
The conveyor system 24 can be disposed within or below the hopper 26. The conveyor 26 can transport the loose paving material 30 through the vehicle portion 18 toward the auger system 16. A grading implement, such as the screed assembly 14, can be attached to the rear of the vehicle portion 18 to receive the paving material 30 from the auger system 16, The screed assembly 14 can be towed by tow arms 20A, only one of which is shown in
More particularly, in order to facilitate formation of the mat 34, the paving machine 10 can be outfitted with the screed plate 13. The screed plate 13 can be configured to spread a smooth even layer of the paving material on the prepared roadbed as the mat 34. The weight and/or a vibration of the screed assembly 14 aids in compressing the paving material and performing initial compaction of the paving material layer into the mat 34. To facilitate laying of the paving material 30 as the mat 34, the screed plate 13 can be heated to a temperature in the range of about 82° to 171° C. (180° to 340° F.). Heating the screed plate 13 can assist the paving material 30 in flowing under the screed plate 13 and can reduce adhesion of the paving material 30 to the screed plate 13.
A cable 56 of a heating assembly 58 passes through the screed frame 54. The cable 56 can extend to physically and electrically connect with a physical and electrical connection of the paving machine 10. The heating assembly 58 passes through the screed frame 54 to a location where a heating element (not shown in
The screed frame 54 can have an access port 62 along a side 64 thereof. The access port 62 allows for withdrawal of the heating assembly 58 including the heating element from the side 64 for repair or replacement of the heating assembly 58. The access port 62 can also facilitate installation of a replacement heating element as needed. The removal of the heating element from the screed assembly 14 is further detailed below.
The screed plate 13 and heating element cover 60 can be constructed of appropriate material(s) such as high wear steel or other metal. Although shown as a substantially flat thin plate in the examples of
The heating assembly 58 can be configured to heat the screed plate 13 and can be connected to a power supply such as an electric generator. A greater number heating assemblies can be provided for each screed plate 13 then are shown, for example, in
As shown in
As shown in
The plurality of cross-members 74 can connect the first raised middle portion 72 with the second raised middle portion 76. The plurality of cross-members 74 can comprise thin plate-like structures and can be spaced apart from one another to provide the space 80.
The trailing edge flange 70 can comprise a thickened portion that can be connected to the first raised middle portion 72. The trailing edge flange 70 can have apertures 84 (
Similarly, the leading edge flange 78 can be constructed in the manner of the trailing edge flange 70. Thus, the leading edge flange 78 can be connected to the second raised middle portion 76. The leading edge flange 78 can be configured to receive fasteners (not shown). The leading edge flange 78 can be positioned adjacent a leading edge 52B of the screed plate 13.
As shown in the embodiment of
Referring now specifically to
The bolt 86 can be oriented with the shaft 91 extending generally transverse to a major surface of the heating element cover 60 (
As shown in
The welded nut 92 can be received on the bolt 86 at the shaft 91 proximal of the retaining element 94 adjacent the head 88. The welded nut 92 can be welded to the shaft 91 according to some examples. The welded nut 92 via abutting interaction with the retaining element 94 and/or head 88 can set a limit to the distal extent of the bolt 86 relative to the heating element cover 60 (
Distal of the retaining element 94, the spring adjustment nut 96 can be threaded on the shaft 91 of the bolt 86. The spring adjustment nut 96 can be abutted by the spring 98 along a distal surface thereof. The spring 98 can be positioned around the shaft 91 of the bolt 86 and can extend to abut the first washer 100 (
In the operable position shown in
The washer 100 can optionally be utilized and can be positioned to abut a proximal surface of the saddle 102. As discussed above, an opposing surface of the washer 100 can be abutted by the spring 98. As shown in
The design for the saddle 102 can facilitate access beneath the middle section 114, which is raised relative to the feet 116, for positioning and coupling of the second washer 104 (if utilized) and the lock element 106 distal of the saddle 102. The lock element 106 via the second washer 104 (if utilized) can connect and retain the saddle 102 to the bolt 86. The second washer 104 or the lock element 106 can be spaced from the distal surface of the middle section 114 a distance so as to facilitate movement of the bolt 86 in a proximal direction. In other cases the second washer 104 can abut the distal surface of the middle section 114. In either case, a proximal movement of the bolt 86 moves the saddle 102 proximally via the connection therebetween. As the saddle 102 is connected to the of the heating element cover 60, movement of the bolt 86 moves the saddle 102 and the heating element cover 60. In this manner, movement of the bolt 86 proximally (moving the head 88 further away from the retaining element 94) can raise the cover off the heating element to create the gap for removal of the heating element) is possible to create or increase the gap between the heating element and the heating element cover 60. Movement of the bolt 86 distally (moving the head 88 toward the retaining element 94) can lower the cover toward or onto the heating element to decrease or eliminate the gap for capturing/covering the heating element) is possible to decrease or eliminate the gap between the heating element and the heating element cover 60.
As shown in the example of
Example machines in accordance with this disclosure can be used in a variety of industrial, construction, commercial or other applications including paving. Such machines can have one or more screed assemblies 12 including one or more screed plates 13 and corresponding heating element covers 60 that are configured to protect the heating element 67 located between the screed plate 3 and the heating element cover 60 from loose debris.
The screed assembly 12 design, in particular with one or more openings 82, space 80 and the plurality of compression spring assemblies 68 can reduce the time and complexity associated with repair or replacement of the heating element 67. These items can also increase repeatability of loading/spacing the heating element cover 60 to OEM specifications.
According to one example, the plurality of compression spring assemblies 68 can be assembled as an OEM component to provide a known desired hold down force on the heating element cover 60 (
In some examples it is desirable to have no desired gap between the heating element cover 60 and the heating element 67. In such situation, an interference resulting in a clamping force can applied by the heating element cover 60 to the heating element 67. After initial OEM assembly, if it is desired to remove the heating element 67 from between the heating element cover 60 and the screed plate 13 (or simply have a small gap therefrom so no clamping force is applied), this can simply be accomplished by adjusting the position of the bolt 86 as described previously.
Furthermore, the present design of the screed assembly 12 with the plurality of compression spring assemblies 68 each having a same or similar length and applied force can promote a more uniform position of the heating element cover 60, which can lead to a more even heat transfer distribution.
Typical screed assemblies such as those of such as those of U.S. Pat. No. 10,017,905 are not configured to provide for ease of removal of the heating element, ease of installation of the heating element, ease of access for removal or installation, easily repeatable positioning of the heating element cover relative to the heating element in the manner of the embodiment discussed above.
The above detailed description is intended to be illustrative, and not restrictive. The scope of the disclosure should, therefore, be determined with references to the appended claims, along with the full scope of equivalents to which such claims are entitled. The claims should be considered part of the specification for support purposes.