US3477769A - Crawler shoe - Google Patents

Description

- Nov. 11, 1969 e. .1. THOMPSO-N CRAWLER SHOE 5 Sheets-Sheet 1 Filed Oct. 25, '19s? G. J. THOMPSON v CRAWLER SHOE Nov. 11, 1969 3 Sheets-Sheet 3 Filed Oct. 25, 1967 INVENTOR GEORGE 3'. THOMPSON BY mSovgwwww %aw-1meg ATTORNEYS United States Patent ABSTRACT on THE DISCLOSURE A laminated crawler shoe composed of a plurality of transversely extending segments, some of which carry apertured link pin lugs and others driving lugs. Wing members are located at each end of the assembly and threaded tension rods extend through mounting openings in the back walls of the wing members and opening in the segments. Nuts, tightened on the threaded rods while the assembled segments are held under compression and the rods are held under tension, and bearing upon the back walls of the wing members tie the assembly together. I

BACKGROUND OF THE INVENTION This invention relates to endless track crawlers, and more particularly to improved shoes for use in crawler tracks.

Crawler tracks are composed of a number of crawler shoes, pivotally interconnected to travel along an orbital path about spaced, toothed drive wheels. Along the lower flight between drive wheels, the weight of the crawler and the structure it carries is imposed upon the shoes through rollers mounted on the frame. The shoes have been formed as monolithic castings, cored to permit quenching and to lighten their weight.

Crawler mounted machines have become larger and heavier with a consequent requirement for larger crawler shoes. During the past few years, the size requirements for shoes have increased, to the point that casting has become an impractical manner of construction. For example, shoes are now in demand of ten feet, or greater, length, and the weight of each shoe is in the order of a number of tons. Consequently, procurement of the shoes has become a problem, and field damage, such as a broken pin lug, or shoe driving lug, means an extensive repair before the shoe can be put back into operation. The increased size also brings problems of materialqualities in different areas. If ductility is desirable, then ductility is obtained even in those areas where it is not wanted, such as at the roller path. Thus, compromise must be made if a monolithic casting is used.

Other difiiculties, such as design compromise to permit ample flow of quenching medium and shifting of internal cores, inherent in most casting operations, are amplified with the increased size of the casting. Gore shifting, if observed prior to putting the shoe in service, results in scrapped castings, or, if not observed, in possible field failures. 7

SUMMARY OF THE INVENTION The object of the present invention is to provide an improved crawler shoe of laminated construction.

Another object of the invention is the provision of a laminated crawler shoe wherein the damaged section can be replaced in a short time, and field repair of a broken part is not necessary.

A further object is to provide. a laminated crawler shoe which can be composed of sections of different degrees of hardness to obtain a composite unit having different material qualities in different areas.

Yet another object is to provide a crawler shoe which 3,477,769 Patented Nov. 11, 1969 can be assembled after the parts have been heat treated, thereby eliminating the need for quench medium passages and the inevitable quench cracking associated with large castings.

Still a further object of the invention is to provide a laminated crawler shoe having means to allow for a novel and simple assembly.

Other objects of the invention will become apparent from the following description of one practical embodiment thereof, when taken in conjunction with the drawings which accompany, and form part of, this speci- .fication.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a perspective view of two laminated shoes made in accordance with the present invention and shown linked together as in use;

FIGURE 2 is an exploded perspective view of one of the shoes;

FIGURE 3 is a top plan view of the shoe;

FIGURE 4 is a partial elevation and partial longitudinal section through the shoe, taken on the line 44 of FIGURE 3;

FIGURE 5 is an end elevation of the shoe, with adjacent, linked shoes shown in phantom lines; and

FIGURE 6 is a vertical transverse section through the center of the shoe, taken on the line 66 of FIGURE 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT The crawler shoe 1 of the present invention is generally similar in over-all shape to a conventional cast shoe. However, it is composed of a center segment and a plurality of segments in similar rightand left-hand pairs arranged in succession on opposite sides of the center segment to form a shoe which is substantially symmetrical about the center segment. The assembled segments are held in compressive abutment my means of nuts on threaded rods that pass through the segments. All of the segments except the outer wing sections, are cut to desired shape from heavy plate, and each carries a link pin lug. Shoes can be designed having different numbers of segments, to suit the needs of different installations. different size and weight of shoes, etc.

In the embodiment shown, there is a center segment 2. This segment has parallel top and bottom edges, with a link pin lug 3 projecting to one side and the opposite side being recessed, as at 4, to provide a working pocket for the link pin lug of the next adjacent shoe of an endless track. The lug 3 has a pin opening 5, and there are two, horizontally aligned, mounting holes 6 in the segment adjacent the bottom. The top surface 7 of the segment is concave transversely of the segment, and forms the central part of a roller path '8.

Next to the center segment, are segments 9 and 9a, segment 9 being to the right and segment 9a being to the left of the center segment as shown in the drawings. These two segments are right-and left-hand replicas, and both have the peripheral shape of the center segment 2. They carry link pin lugs 10 and 10a with openings 11 and 11a, and have the concave recesses 12 and 12a in their opposite edges. The top surfaces 13 and 13a are oppositely curved in continuation of the curvature of the center segment 2 to complete the roller path 8. The sections also have pairs of mounting openings 14 and 14a similarly located to the mounting openings 6 of the center segment.

At the sides of the segments 9 and 9a, there are shoe driving lug segments 1-5 and 15a. Here again, the seg ments are right and left replicas. Segments 15 and 15a carry link pin lugs 16 and 16a, but these lugs project in the opposite direction from the lugs 3, 10 and 10a. The

side edges opposite the link pin lugs are recessed at 17 and 17a. Projecting vertically from the top edges of segments and 15a are driving lugs 18 and 18a for engagement with the teeth of the driving wheels of the crawler to advance the track about its pivotal path. The segments have pin openings 19 and 19a in the lugs 16 and 16a, and each has a pair of mounting openings 20 and 21, similarly arranged to the mounting openings in the previously described segments.

Next to the driving lug segments are segments 21 and 21a. These are approximately the same as the driving lug segments except that they do not have driving lugs. They have link pin lugs 22 and 22a, similarly positioned to the lugs 16 and 16a of the driving lug segments, and the opposite edges are recessed at 23 and 23a. There are pin openings 24 and 24a in the lugs 22 and 22a, and mounting openings 25 and 25a adjacent the segment bottoms.

The last of the link pin lug bearing segments are segments 26 and 26a mounted adjacent the segments 21 and 21a. These have their link pin lugs 27 and 27a oppositely disposed to the last described segments and projecting in the same direction as the center segment 2 and segments 9 and 9a. These segments are recessed, as at 28 and 23a, and have pin openings 29 and 29a in the lugs 27 and 27a, and mounting openings 30.

The assembly of units is completed by a wing member 31 on the right and a wing member 32 on the left. These members give the assembly its desired over-all length of bearing surface on the ground and provide housings for the securing means which tie the assembly together. As these two membres are slightly different, they will be separately described.

Wing member 31 has a vertical back wall 33, a bottom bearing plate 34, sides 35 and a top 36. The back wall is rectangular and has mounting openings 37, similarly arranged and spaced to the mounting openings in the several segments. The bottom plate 34 is welded at its back edge along the bottom edge of the back wall. The sides are welded to the back wall and to the bottom plate. A center brace is welded to the top surface of the bottom plate and the forward surface of the back wall to stiffen the assembly. The top 36 has its outer edge flush with the outer edges of the sides and bottom so that these four edges lie in a single vertical plane and define an open mouth through which a tensioning tool can be inserted, and bearing walls against which a portion of the tensioning tool may abut. The top terminates short of the back wall, leaving an access opening 38 to facilitate assembly as will be described.

Wing member 32 has a back wall 39, bottom bearing plate 40, sides 41 and a front wall 42. The back, bottom plate and sides are welded together in the same manner as those of the wing member 31. Wing member 32 has no top, but the front wall 42 is welded to the outer ends of the sides and bottom plate. A brace 43 is welded to the bottom plate and to the back and front walls. The back wall has mounting openings 44 similar to those previously described.

All of the various units making up the crawler shoe are held in assembled relation by means of two tie rods 45, which pass through the mounting openings of the various units. The rod ends are threaded and nuts 46 are threaded onto the rod ends which will be in the wing 32, and nuts 37 are to be threaded onto the rod ends which project into the wing member 31.

y In assembling the shoe, the various units are arranged in the order above described, and can be assembled either directly on the tie rods 45, or they may be preliminarily arranged by the use of positioning pins through the mounting openings. If assembly dowels, or rods, are used, they will be Withdrawn and the rods 45 inserted through the open end of the wing member 31 and through the mounting openings in all the units until the leading ends of the rods project into the open area of the wing member 32. At this time, nuts 46 will be threaded on the ends of the rods within the wing member 32 and brought into abutment with the back wall of that member. Nuts 47 will be threaded onto the ends of the rods projecting into the member 31, and can be rotated into contact with the back wall of that member. No attempt is made at this time to draw up on the nuts to tighten the assembly. A suitable jack, such as that shown at 48 in dotted lines in FIGURE 4, has a threaded coupling 49 on the end of its piston rod 50, and this coupling is screwed onto the projecting end of one of the rods 45. The jack has an abutment plate 51 which is brought into bearing contact with the outer end of the wing formed by the edges of the bottom, side and top walls. The jack is then actuated to draw in its piston rod to bring the units of the assembly into compressive'abutment and to tension the rod 45. The force applied by the jack will be very great, in the order of three million pounds for large shoes, and the assembly will be extremely rigid under this compressive force. By inserting a proper tool through the access opening 38 in the wing member 31, the nut 47 on the rod under tension can be drawn up tightly against the back wall 33. After the nut is tightened, the jack can be released and the compressive force on the assembled units will be maintained by the tie rod. The same procedure can be followed with the second tie rod to complete the assembly.

The completed shoe will be a tensioned assembly which will hold the individual units against any possible movement relative to the assembly as a whole. At the same time, the several segments making up the assembly can have different qualities as may be desired for their particular location in the assembly. For example, the center segment 2 and the segments 9 and 9a may be quite hard to provide the proper surface for the roller path. At the same time, other segments and the wing members can have more ductility to better withstand the heavy bending loads which are imposed. The laminated shoe can be fabricated very quickly without the usual long lead times associated with large castings. If the shoe is damaged in service, such as by breaking a link pin lug or driving shoe lug, it is a relatively simple repair job to disassemble the units and add a new segment of the required configuration. The laminated construction lends itself to many variations as far as shoe design is concerned. Yet all will be equally simple to fabricate and to repair.

While one practical embodiment of the invention has been disclosed, it will be understood that various modifications of the particular structural arrangements shown and described may be made.

What is claimed is:

1. Crawler shoe comprising, a plurality of segments at the center extending transversely of the shoe having link pin lugs projecting to one side of the shoe, the segments having upper surfaces concavely curved transversely of the segments to form a continuous arcuate roller path, segments at each side of the first-mentioned plurality having link pin lugs projecting to the other side of the shoe and driving lugs extending vertically above the segments, a separable wing member segment at each end of the shoe having back walls in abutment with adjacent segments, all of the segments and the wing member segments having mounting openings in alignment lengthwise of the shoe, a tension rod having threaded ends extending through the mounting openings and having the threaded ends projecting into the wing member segments, and nuts on the threaded ends of the rod and in abutment with the end Walls of the wing member segments holding the segments in compressive assembly and the tension rod in tension.

2. Crawler shoe as claimed in claim 1 wherein, one of the wing member segments has an open end aligned with the tension rod and a wall surrounding the open end providing an abutment for a tool to tension the tension rod.

3. Crawler shoe as claimed in claim 1 wherein, the segments forming the roller path are of very hard material and the remainder of the segments and wing member segments are of more ductile material.

4. Crawler shoe as claimed in claim 1 wherein, all of the segments and wing member segments have second aligned mounting openings, and there is a second tension rod with nuts on the ends bearing against the wing member segments back walls.

References Cited UNITED STATES PATENTS Leymer 30557 Knox 305--57 Harrington 305-58 X Matheny 305-58 X Davidson 305-57 X RICHARD J. JOHNSON, Primary Examiner

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