The present application relates generally to apparatuses and systems that enable the ease of removal and installation of screed heating elements in working machines. More particularly, the present application relates to an apparatus and and system for clamping the screed heating elements with a consistent clamping force that is evenly distributed to promote improved heat transfer.
Pavers or paving machines are working machines used in a 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. 9,181,662 have an opening on the trailing edge. Although this can improve heat transfer and access to the heater, it can allow for asphalt and debris to get into the heating chamber. Debris can negatively impact heater removal and installation, heat transfer uniformity, etc. Other screed designs utilize a separate cover and/or multiple hold down components. These components and/or the screed plate need to be removed to change heating elements. However, the heavy nature of the equipment and the design of conventional screed assemblies typically requires that any such maintenance be carried at a depot or shop location, which can increase time spent in maintenance.
In one example, a screed assembly for use with a paving machine is disclosed. The screed assembly can comprise: a screed plate; a holder configured to be removably connected to the screed plate and configured to be positioned thereon, wherein when connected thereto the screed plate and the holder form a channel having an opening at one end thereof; and a heater assembly having a heating element configured to be received in the channel and to be aligned by the holder when so received relative to an axis of symmetry of the screed plate.
In another example, a paving system for laying an asphalt paving material is disclosed. The system can comprise: a paving machine and a screed assembly configured to be removably connected to the paving machine. The screed assembly can comprise: a screed plate; a holder configured to be removably connected to the screed plate and configured to be positioned thereon, wherein when connected thereto the screed plate and the holder form a channel having an opening at one end thereof; a heater assembly having a heating element configured to be received in the channel; and a screed frame configured to be spaced from the screed plate and holder along trailing sides thereof to provide an first opening for access to the holder.
In another example, a screed assembly for use with a paving machine, is disclosed. The screed assembly can comprise: a screed plate; a holder configured to be removably connected to the screed plate and configured to be positioned thereon, wherein when connected thereto the screed plate and the holder form a channel having an opening at one end thereof; and a heater assembly having a heating element configured to be received in the channel, wherein the channel and heating element are separated from a trailing edge of the screed plate by the holder such that the holder acts as a cover to protect the heating element from debris.
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.
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 heater assembly 58 passes through the frame 54. The cable 56 can extend to physically and electrically connect with a physical and electrical connection of the paving machine 10. The heater assembly 58 passes through the frame 54 to a location where a heating element (not shown in
The frame 54 can have an access port 62 along a side 64 thereof. The access port 62 allows for withdrawal of the heater assembly 58 from the side 64 for repair or replacement of the heater assembly 58. The frame 54 can be spaced from the screed plate 13 and the holder 60 along the rear side 52. This arrangement can provide a second access port 66 to the holder 60 along the rear side 52. The second access port 66 can be configured to allow personnel to reach fasteners 68 (e.g., nuts and bolts) that physically connect the holder 60 to the screed plate 13. By loosening these fasteners 68, the clamping force of the holder 60 on the heater assembly 58 can be reduced or removed to facilitate withdrawal of the heater assembly 58 through the access port 62.
The screed plate 13 and holder 60 can be constructed of appreciate material such as high wear steel or other metal. The contour of the screed plate 13 can determine the quality, evenness and smoothness of the paving material that is being laid down. As such the screed plate 13 (and holder 60) can be flexed under tensile loads during use to achieve desired crowning or other surface contours. The heater 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 heater assemblies can be provided for each screed plate 13 then is shown, for example, in
In
The holder 60 can be physically connected to the screed plate 13 by the fasteners 68. The holder 60 can comprise a metal plate constructed of a metal such as steel having a thickness of several millimeters, for example. As best shown in
The holder 60 can be symmetrically constructed along an axis A (
The first transition section 104 can connect with the first plurality of flanges 100 at a trailing edge side 112 and can extend away from the screed plate 13 at an angle to a leading edge side 114. The first transition section 104 can connect to the raised middle section 108 at the leading edge side 114. Due to the shape of the first transition section 104, the trailing edge side 112 can be positioned relatively closer to (at) the screed plate 13 relative to the leading edge side 114. The first transition section 104 can extend generally parallel with the trailing edge 52A and the axis A (
The second transition section 106 can mirror the construct of the first transition section 104 but in an opposing manner as it is positioned across the axis A (
The raised middle section 108 can be connected to the first transition section 104 and the second transition section 106 and can have a relatively flat extent therebetween. Together the raised middle section 108, the first transition section 104 and the second transition section 106 can form a channel 120 that is also bounded by the screed plate 13. This channel 120 can be configured to receive a heating element 122 of the heater assembly 58 therein. The channel 120 can have an opening 124 on a single side corresponding to the second edge 64A and the side 64 (
When the holder 60 is connected down fully to the screed plate 13, the raised middle section 108 can be spaced from the screed plate 13 a distance D1 that is less than a thickness T of the heating element 122 of the heater assembly 58. Thus, an interference resulting in the clamping force is applied by the holder 60 to the heating element 122 as a result in the difference between the distance D1 and the thickness T. As discussed previously, if it is desired to remove the heating assembly 58 including the heating element 122 from between the holder 60 and the screed plate 13, the nuts of the fasteners 68 can be loosened (the nuts of the fasteners 110 can remain in a fully tightened position) to increase the distance D1 to reduce or remove the clamping force. This configuration facilitates removal of the heating element 122 from the channel 120 through the opening 124.
Thus, in brief summary and according to the embodiments of
As shown in
The heating element 122 can be configured as a thin, elongate sheet or ribbon and formed from a resistive conductor, such as a thin conductive wire or ribbon. However, alternate designs of heating element 122 can be utilized, such as those that present a broader thickness profile due to a circular cross-sectional shape. A resistive conductor within each heating element 122 terminates with a set of leads or electrical conductors that protrude from the holder 60.
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 holders 60 that are configured a clamping plates to apply a clamping force to a heater assembly 58 having heating element 122 sandwiched between the screed plate 13 and the holder 60. The screed assembly 12 can reduce the time and complexity associated with repair or replacement of the electric heater assembly 58, in particular, the heating element 122. In some embodiments, the heating element 122 can simply be slid out from between the holder 60 and the screed plate 13 by simply loosening easily accessible nuts at a rear (trailing side) of the screed assembly 12. Other nuts such as those that are relatively more inaccessible near a leading side of the screed assembly 12 and screed plate 13 do not need to be loosened to facilitate such removal of the heating element 122. The holder 60 and screed plate 13 can remain connected together during the removal of the heating element 122 and do not need to be entirely separated. Thus, the screed plate 13 does not need to be removed.
Furthermore, the present design of the screed assembly 12 in some embodiments facilitates ease of assembly of the heating element 122 with the holder 60 and the screed plate 13 in a manner the promotes more even heat transfer distribution. More particularly, after nuts on the trailing side of the screed assembly 12 are loosened a replacement or OEM heating element 122 can be inserted from a side. Such insertion can be into the channel 120 formed by the holder 60. The configuration of this channel 120 and holder 60 can align the heating element 122 symmetrically with respect to the axis A1 of symmetry of the screed plate 13. Such alignment promotes more even heat distribution.
Additionally, the holder 60 can be configured to enclose the heating element 122 on multiple sides including on the trailing edge side so as to prohibit or deter the entry of paving material adjacent the heating element 122. The design of the holder 60 with a large raised middle portion, single piece construction and symmetric shape promotes a more even clamping force application, which can avoid or reduce the likelihood of the development of hot spots on portion so the screed plate 13.
Typical screed assemblies such as those of such as those of U.S. Pat. No. 9,181,662 are not configured to provide for one or more of even clamping force application, ease of removal of the heating element, ease of installation of the heating element, ease of access for removal or installation, alignment of the heating element and/or enclosure of 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.
Number | Name | Date | Kind |
---|---|---|---|
6318928 | Swearingen | Nov 2001 | B1 |
7427174 | Dearing | Sep 2008 | B2 |
8113737 | Mahler | Feb 2012 | B2 |
8113738 | Mahler | Feb 2012 | B2 |
8157474 | Mahler | Apr 2012 | B2 |
8517630 | Graham | Aug 2013 | B2 |
9181662 | Kopacz et al. | Nov 2015 | B2 |
9249544 | Caputo | Feb 2016 | B2 |
9885158 | Grimm et al. | Feb 2018 | B2 |
9988771 | Caputo | Jun 2018 | B2 |
10113274 | Caputo | Oct 2018 | B2 |
10280571 | Caputo | May 2019 | B2 |
10443196 | Caputo | Oct 2019 | B2 |
20140377003 | Kopacz et al. | Dec 2014 | A1 |
20160186389 | Graham | Jun 2016 | A1 |
20190024326 | Caputo | Jan 2019 | A1 |
20190390416 | Caputo | Dec 2019 | A1 |
Number | Date | Country |
---|---|---|
H10252012 | Sep 1998 | JP |
2018136049 | Jul 2018 | WO |