The present disclosure relates generally to an extension mounting system for attaching a screed extension to a screed, and more particularly to an extension mounting system including a catch engaging surface pivotable with an extendible frame portion of the screed and shaped to engage a mounting catch of the screed extension.
A paving machine, such as an asphalt paver, is generally a self-propelled machine designed to receive, convey, distribute, and partially compact paving material, such as asphalt. Typically, the paving machine receives the paving material in a hopper positioned at the front of the machine, conveys the paving material from the hopper to the rear of the machine with parallel slat conveyors, distributes the paving material along a desired width, and compacts the paving material into a mat with a screed. The width of the screed, which may be adjustable, typically defines the paving width provided by the particular paving machine. In particular, some paving machines include frame portions that are hydraulically extendible in the lateral direction to increase the paving width. Mechanical extensions, such as bolt-on extensions, may also be utilized for increasing the paving width provided by the based screed.
Mechanical extensions can be relatively heavy and typically require an additional piece of equipment, such as a forklift or crane, for lifting the mechanical extension into alignment with the base screed. Once the mechanical extension and base screed are aligned, the bolted connections are secured to maintain proper positioning of the mechanical extension. Often, these bolted connections are numerous and difficult to access. Thus, attaching a mechanical extension to a base screed, particularly when conducted in the field, can be difficult, time-consuming, costly, and may require equipment that is not readily available.
U.S. Pat. No. 3,702,578 to Davin teaches a quick change screed extension for paving machines. In particular, Davin teaches an adapter plate for a side wall of a main screed having a plurality of socket lugs. The extension includes upwardly extending pins received in the socket lugs when the screed extension is raised relative to the main screed, such as by using a lift handle. When the pins are appropriately positioned through the socket lugs, wedges may be positioned through slots of the pins to maintain the position of the extension. Although the Davin reference may teach a suitable extension installation system, the Davin installation means appears to be applicable to relatively lightweight extensions that may be lifted by hand using the lift handle.
The present disclosure is directed to one or more of the problems or issues set forth above.
In one aspect, a screed has a lateral extension axis and includes an extendible frame portion having a catch engaging surface of an extension mounting system. The extendible frame portion is expandable along the lateral extension axis and pivotable relative to a pivot axis perpendicular to the lateral extension axis. A screed extension has a screed extension frame supporting a mounting catch of the extension mounting system. In a mounting configuration, the extendible frame portion is pivoted about the pivot axis in a first direction to a lowered mounting position, and the extendible frame portion is axially expanded to an extended mounting position in which the catch engaging surface and the mounting catch are vertically aligned. In a lifted configuration, the extendible frame portion is pivoted about the pivot axis in a second direction to a raised lifting position, the catch engaging surface and the mounting catch are in mating engagement, and the screed extension is supported on the extendible frame portion using the extension mounting system.
In another aspect, a method for attaching a screed extension to a screed includes pivoting an extendible frame portion of the screed about a pivot axis in a first direction to a lowered mounting position to position a catch engaging surface of the extendible frame portion below a mounting catch of the screed extension. The extendible frame portion is axially expanded to an extended mounting position to vertically align the catch engaging surface and the mounting catch. The extendible frame portion is then pivoted about the pivot axis in a second direction to a raised lifting position to bring the catch engaging surface and the mounting catch into mating engagement and support the screed extension on the extendible frame portion.
In yet another aspect, a screed extension for a screed having an extendible frame portion includes a screed extension frame supporting a mounting catch of an extension mounting system. The mounting catch is supported from a vertical mounting wall of the screed extension frame and includes an inner surface shaped for mating engagement with a catch engaging surface of the extendible frame portion in a raised lifting position of the extendible frame portion. The screed extension also includes a set of wall openings through the vertical mounting wall positioned for alignment with a corresponding set of wall openings through the extendible frame portion in the raised lifting position. The wall openings through the vertical mounting wall are shaped to receive a set of locking devices of an extension locking system.
An exemplary embodiment of a paving machine 10 is shown generally in
A conveyor may also be supported on the machine frame 16 and may convey the paving material P received within the hopper to a screed 18, such as a free floating screed, coupled with the paving machine 10, such as via tow arms, at a rear portion 20 of the machine frame 16. The screed 18 may distribute and, at least partially, compact the paving material P into a mat on the desired paving surface S. In particular, a screed plate 22 at the bottom portion of the screed 18 may flatten and compress the paving material P. The tractor portion 12 of the paving machine 10 may also include hydraulic drives and controls, along with various other known paving machine components, for operating various systems and components of the paving machine 10. The screed portion 18 of the paving machine 10 may also include additional components and systems, such as, for example, leveling arms, vibrators, sensors, and controllers, as are known to those skilled in the art. Such additional systems and components are not within the scope of the present disclosure and, thus, will not be discussed herein in greater detail.
The screed 18 may generally include a main frame portion 24, a first extendible frame portion 26, and a second extendible frame portion 28. Each extendible frame portion 26 and 28 may be mounted on the main frame portion 24 and may be expandable along an extension axis A2, also referred to as a lateral extension axis, of the screed 18. For example, the extendible frame portions 26 and 28 may be axially expandable along the extension axis A2 to an extended position defining a first paving width w1. In particular end walls 30 and 32, which are axially movable away from the main frame portion 24, may roughly define an adjustable paving width. The extendible frame portions 26 and 28 may also be axially shortened along the extension axis A2, such as by moving the end walls 30 and 32 toward the main frame portion 24, to a shortened position defining a second paving width w2, shown in
According to a specific example, the first and second extendible frame portions 26 and 28 may be hydraulically extendible, or expandable, using respective extension cylinders 34 and 36, as is known by those skilled in the art. In particular, the extendible frame portions 26 and 28 may be expanded or shortened to effectively extend or shorten the adjustable paving width. According to some embodiments, each extendible frame portion 26 and 28 may be independently adjustable. Since the screed assembly 18 is substantially symmetrical with respect to a longitudinal centerline of the paving machine 10, only the first extendible frame portion 26 will be referenced throughout the remaining disclosure. However, it should be appreciated that the extendible frame portion 28 may have similar components and capabilities.
Turning now to
A screed extension 50, also referred to as a rigid or mechanical extension, is shown generally in
Turning now to
Returning to
At a second stage, the mounting may be facilitated by axially expanding the extendible frame portion 26 to an extended mounting position, as shown in
After the catch engaging surface 62 and mounting catch 64 are moved into vertical alignment, the extendible frame portion 26 may be pivoted about the pivot axis A3 in the second direction d2 to a raised lifting position, as shown in
According to the first exemplary embodiment, the mounting catch 64 may include an elongate channel 70 shaped to receive an upper end wall surface 72, which defines the catch engaging surface 62. The elongate channel 70 may be defined by an attachment 74 fastened to the end wall 54 of the screed extension 50. As shown, attachment flanges 76 and 78 may be bolted or otherwise secured to the end wall 54, such as via a bolted connection 80. As shown, the attachment 74 may extend a majority of the length of the screed extension end wall 54 and may define a channel 70 sized to receive the screed extension end wall 54 and the extendible frame portion end wall 30. Although a bolt-on attachment is shown, it should be appreciated that the attachment 74 and channel 70 may be integral with the screed extension frame 52.
An extension orientation adjustment system 90 may be provided for adjusting an orientation of the screed extension 50 relative to an orientation of the extendible frame portion 26 once the screed extension 50 is supported on the extendible frame portion 26. The extension orientation adjustment system 90 may include a pair of spaced apart vertical adjustment devices 92 and 94, such as push bolts, coupled with the attachment 74. As shown, each of the adjustment devices 92 and 94 may be positioned through the attachment 74 at the elongate channel 70 and may be independently movable to engage the upper end wall surface 72. According to a specific example, each of the adjustment devices 92 and 94 may be threadably received or withdrawn through the attachment 74 to engage the upper end wall surface 72 and raise or lower the screed extension 50 relative to the extendible frame portion 26. As stated, the adjustment devices 92 and 94 may be independently adjustable to effectively adjust the orientation of the screed extension 50 relative to the orientation of the extendible frame portion 26. For example, orientation may be adjusted to properly align the screed plate 58 of the screed extension 50 with the screed plate 22 of the screed portion 18.
Referring to both
Referring specifically to
With reference to
An extension orientation adjustment system 156, which may be similar to the extension orientation adjustment system 90 discussed above, may be provided for adjusting an orientation of the screed extension 50 relative to an orientation of the extendible frame portion 26. In particular, the extension orientation adjustment system 156 may include a pair of spaced apart vertical adjustment devices 158 and 160, such as push bolts, coupled with the extendible frame attachment 152. As shown, each of the adjustment devices 158 and 160 may be positioned through the attachment 152 or, more specifically, the curved support surface 144, and may be independently movable to raise or lower one of the extendible frame portion 26 and the screed extension 50 relative to the other. As stated above, the adjustment devices 158 and 160 may be independently adjustable to effectively adjust the orientation of the screed extension 50 relative to the orientation of the extendible frame portion 26.
Referring generally to
To maintain these locked positions of the locking wedges 174, the extension locking system 162 may also include a wedge actuation device 176 for selecting and maintaining a desired holding force acting upon an integral structure 178 supporting the locking wedges 174. As best shown in
Heat treating the integral structure 178 supporting the locking wedges 174 may create a spring force that will keep the joint tight even with a small amount of setting. This may remove the need for spring washers. However, it should be appreciated that a number of alternative devices may replace the wedge actuation device 176. For example, any locking device that is capable of extending and retracting the wedges 174 may be used. Some other options may incorporate springs to maintain a clamp force without tightening the locking device to account for movement and wearing of the wedges 174 during operation, or may use a hydraulic cylinder with constant pressure to maintain the clamp force.
The present disclosure finds potential application in any paving machine that utilizes screed extensions to increase paving width. Further, the disclosure may be applicable to mechanical or rigid screed extensions for paving screeds that have extendible and pivotable frame portions. Further, the disclosure may be specifically applicable to mounting systems and methods for attaching the screed extension to an extendible and pivotable frame portion of a screed to define a screed assembly.
Referring generally to
The screed 18 generally includes a main frame portion 24 and at least one extendible frame portion 26. The extendible frame portion 26 may be axially expandable and retractable along a lateral extension axis A2, and may be pivotable relative to a pivot axis A3 perpendicular to the lateral extension axis A2. The paving width provided by the screed 18 and the one or more extendible portions, such as extendible frame portion 26, may be further extended by attaching a screed extension 50 to the extendible frame portion 26 to define a screed assembly 59. Although not discussed in detail, it should be appreciated that an additional screed extension may be attached at the opposing end of the screed 18 to the extendible frame portion 28. Further, it should be appreciated that one or more additional screed extensions, similar to extension 50, may be supported on screed extension 50.
In particular, and according to the extension mounting system 60 and method provided herein, the extendible frame portion 26 may be pivoted about the pivot axis A3 in a first direction d1 to a lowered mounting position to position the catch engaging surface 62 below the mounting catch 64, as shown in
After the screed extension 50 has been lifted and mounted using the extension mounting system 60, an extension orientation adjustment system, such as systems 90 and 156, may be used to adjust the orientation of the screed extension 50 relative to the orientation of the extendible frame portion 26. Once the orientation is acceptable, an extension locking system, such as systems 100 and 162, may be used to secure the position and orientation of the screed extension 50 relative to the orientation of the extendible frame portion 26. It should be appreciated that numerous modifications may be made to the specific embodiments provided herein without deviating from the scope of the disclosure.
The extension mounting system and method provided herein provides a relatively quick and effective means for attaching a screed extension to an extendible and pivotable frame portion of a screed. The disclosed system and method utilizes the extendible and pivotable frame portion to lift and initially position the screed extension, while additional systems orient and lock the desired position and orientation. Thus, the system and method does not require the use of additional equipment, such as forklifts or cranes, to lift and mount the screed extension, and does not include numerous and difficult to access connections for securing the position of the screed extension to the screed.
It should be understood that the above description is intended for illustrative purposes only, and is not intended to limit the scope of the present disclosure in any way. Thus, those skilled in the art will appreciate that other aspects of the disclosure can be obtained from a study of the drawings, the disclosure and the appended claims.