GB2031824A - Crawler vehicle construction - Google Patents

Abstract

The crawler side frame assemblies of a tracked vehicle each comprise a central member 40 to which is releasably secured two modular end members 38, 46. The central member 40 is integral with the support frame of the vehicle and carries track rollers 44a-d which receive a substantial portion of the design load of the vehicle. End members 38 and 46 carry a drive sprocket 34 and an idler roller 48 respectively. First and second bogies 60,70 each having two track rollers 62a,b are pivotally connected to the ends of the central member 40 and carry the remaining portion of the design load. <IMAGE>

Description

SPECIFICATION Crawler vehicle construction This invention relates to crawler or track-type vehicles and more particularly to a structural arrange ment of the track frame with the supporting frame for the vehicle.

In crawler or track-type vehicles particularly those which require erection in the field, such as power 'shovels, in order to facilitate shipment crawler side frames including the drive sprocket for the track, idler roller and supporting track rollers are conventionally manufactured as completely separate items which are subsequently to be bolted or otherwise attached to a supporting frame or undercarriage for the vehicle. In considering the load transmission characteristics of such a structure it can be seen that this creates a chain of connected structures, and each link in the chain of connected structures is required to withstand the entire design load. For example, the track rollers supporting a crawler track receive loads through the side frames carrying the track, from the lower frame or undercarriage of the vehicle.Each of the structures and connections must be designed to handle the maximum load conditions. Accordingly, this form of construction for track-type vehicles is unduly complex and expensive by reason of the number of separate portions of the structure which must be designed and constructed to carry the entire design load.

With regard to those types of crawler or track-type vehicles which must be assembled in the field it is conventional to manufacture and ship the entire crawler frame structure including the sprockets and idler rollers which must carry the track as an integral unit which is subsequently attached to the support ing frame or undercarriage of the vehicle. Particular liy with regard to the larger vehicles of this type, i.e.

power shovels, these crawler frames are exceeding ly long and heavy for shipping purposes and thereby difficult and expensive to handle. It has been suggested that the foregoing problem can be solved by making the drive portion of the crawler frame, i.e.

the crawler sprocket and associated gearing and drive motor a separate modular portion of the crawlerframe. However, in so doing, it is difficult to make satisfactory provision for providing track rollers which will prevent those lower portions of the track adjacent the crawler sprocket from buckling, or stated another way, it is difficult to make sufficient provision for load equalisation along the entire length of the lower portion of the track between the crawler sprocket and the front idler roller.

According to the present invention there is provided a track-type vehicle operating on endless crawler tracks, each said crawler track extending around and being driven by a crawler sprocket at one extremity of its travel and extending around an idler roller at its other extremity of travel, and having a pair of crawler side frame assemblies, each crawler side frame assembly comprising: a central side member extending laterallyfrom and being integral with a supporting frame for the vehicle, said side frame member having at least one track support roller carrying said crawler track in a first direction of travel and track rollers guiding said track in a second direction of travel and at least partially supporting said vehicle on the surface on which it is travelling; a first modular member rotatably carrying at least said idler roller, said first modular member being detachably secured to a first end of said side frame member; a second modular member carrying at least said crawler sprocket, said second modular member being detachably secured to a second end of said side frame member; first and second additional track roller means arranged to be adjacent, respectively, said idler roller and said crawler sprocket; and mounting means for pivotally connecting said first and second additional track roller means to said side frame member.

The preferred embodiment of the invention enables satisfactory provision to be made for load equalisation along the entire length of the lower portion of the crawler track from idler roller to crawler sprocket. Further, the preferred embodiment provides for a track-type vehicle a main frame and crawler frame structure which for load transmission purposes is an integral structure, and provides in a modu larised crawler frame structure an arrangement for a track roller or rollers adjacent the idler roller and crawler sprockets which provides for greater load equalisation and which can respond to changes in level of the track as it proceeds from the idler roller orto the crawler sprocket.

The invention will be more readily understood from the description of a preferred embodiment given hereinbelow, which preferred embodiment is described in the context of the use of the invention on a power shovel, reference being had to the accompanying drawings, in which: Figure 1 is a side elevation of a power shovel incorporating an embodiment of the invention; Figure 2 is a top elevation and broken view of the supporting or lower frame structure and one crawler frame structure for the power shovel illustrated in Figure 1; Figure 3 is a side elevation of the Figure 2 view; and Figure 4 is an exploded, partial view of the forward portion of the Figure 2 embodiment.

In Figure 1 is shown a power shovel 10 which is typical of a vehicle on which the preferred embodiment of the invention might be used. The overall construction of the power shovel forms no part of this invention and such a power shovel is described in detail in U.S. Patent No. 3,501,034.

Power shovel 10 is equipped with a body 12 supported for rotation on a lower or supporting frame 14. The shovel can be moved from place to place by operation of a pair of laterally-spaced and parallel endless crawler or track assemblies 15, only one of which is shown in Figure 1. The crawler assembly is described hereinbelow in greater details in connection with Figures 2-4. The body can be rotatably moved to swing from side to side by suitable power means mounted within the housing of body 12.

A bucket or dipper 16 is pivotally connected at 17 two a handle 18which is in turn pivotally connected to a stiffleg 20 by a head shaft 19. The stiffleg is pivotally connected to the machine body by foot pins 22. A hoist frame 24 is also connected to head shaft 19, and a hoist link 26 ties the hoist frame to dipper 16 by pivots 27 and 28. The hoist frame, hoist link, handle and dipper move as a unit about the head shaft, and there is no relative movement among these parts except when the dipper moves about its pivotal connection 17 with the handle in changing pitch. A hoist line 15 controls movement of the hoist frame about the head shaft, and a crowd mechanism generally indicated by the reference numeral 30 controls movement of the hoist frame and stiffleg about its foot pins.

As stated, this power shovel is mounted for movement on crawler structures 15 which are carried buy a supporting or lower frame 14. The details of construction of the crawler assembly and its relationship to the supporting frame 14 are described below.

Figures 2 and 3 illustrate in details the construction of one of the crawler assemblies necessary to carry the above-described power shovel or other similar type vehicle. Figure 2 illustrates the relationship of that crawler assembly to the supporting frame 14 as well as to the mechanism for driving that crawler assembly.

An endless crawler track 32 formed of a plurality of crawler shoes 33 extends around and is driven by a crawler sprocket 34 at one extremity of the travel of the crawler track. Track 32 extends around, at the other extremity of its travel, an idler roller 48. These parts are carried by the crawler side frame structure 15 formed of central side frame member 40 and modules 38 and 46.

The major portion of the crawler side frame structure is constituted by the central side frame member 40 which, as is most apparent from Figure 2, is an extension of and integral with the supporting frame 14 for the vehicle. in the latter case, the supporting frame 14 constitutes the lower frame of the power shovel described above. Central side frame member 40 carries a plurality or track rollers 44a through d which distribute the weight of the vehicle along that portion of the length of the lower portion of track 32 which is coextensive with the length of central side frame member 40. The central side frame member 40 additionally carries at least one upwardly extending track roller 42b for support ing track 32 in the upper portion of its travel.Central side frame member 40 terminates at its ends in flange members 50 and 51 which, respectively, contain a series of bolt holes, such as bolt holes 52 illustrated in connection with flange member 50 in Figure 4 In the illustrated embodiment the front portion of the crawler assembly is completed by a module 46 which rotatably carries about pivot 47 an idler roller 48. In addition, module 46 has mounted thereon a support roller 42a which supports the upper portion of the track at this portion of its path. Module 46 terminates at its rear end in a flange member 54 which fits flush with flange member 50 and contains bolt holes 55 which are co-linear with the bolt holes 52 on central side frame member flange 50. Thus, module 46 can readily be bolted to central side frame member 40 by means of the series of bolts 57.

The rearward portion of the crawler assembly in this embodiment is completed by a module 38 which rotatably carries a crawler sprocket 34 mounted on the module by means of axle 36. In addition, module 38 includes a housing 70 in which can be mounted the driving mechanism for the crawler sprocket in the form of a drive motor and suitable reduction gears. This module is equipped with a support roller 42c which carries the upward portion of the track at this point in its travel.

In a like manner as decribed hereinabove in connection with module 46 this module is bolted to the rearward flange member 51 of central side frame member 40. Thus, a flange member 58 which fits flush with flange member 51 is provided on module 38, and the two are bolted together by means of the series of bolts 59.

As is clear from viewing the drawings, the track rollers44athrough44d provide no supportforthe track in those portions of its travel between those track rollers and, respectively, the idler roller 48 and the crawler sprocket 34. In the rough terrain which is usually encountered by vehicles of this type without further provision the track would buckle under many circmstances, and repeated action of this type would likely cause severe damage to the track. Therefore, it is necessary that some additional support be provided and this support must be provided in a way which will most nearly accommodate the natural motion of the track, at those points of its travel, where, for example, in forward travel, it is just issuing from the idler roller or being picked up by the crawler sprocket 34.

In the crawler assembly illustrated in Figures 2 and 3 this additional support is provided by bogies 60 and 70 which each carry a pair of additional track rollers in the manner shown. The relationship of bogie 60 to the remainder of the structure and its construction are described in greater detail hereinbelow.

Referring to Figure 4 it is seen that bogie 60 is formed of a pair of triangular members 64a and 64b which at the two lower corners have pivotally mounted therein track rollers 62a and 62b. The upper corner of the bogie structure is equipped with a bushing 63 which extends between the triangular members 64a and 64b.

The interior vertical portions of flange member 50 of central side frame member 40 are equipped with bosses 66a and 66b having holes therein through which a pin 68 can be inserted while being inserted through the bushing 63 of bogie 60. Accordingly, the bogie 60 is pivotally carried by the central side frame member so as to allow it to accommodate to the particular motions or slight changes in level of the track at this portion of its travel. In addition, by virtue of the construction and arrangement of bogie 60, the track roller 62a and 62b are so mounted and positioned that they provided the needed buckling prevention as well as additional load equalization along the length of the track.

Claims (6)

1. A track-type vehicle operating on endless crawler tracks, each said crawler track extending around and being driven by a crawler sprocket at one extremity of its travel and extending around an idler roller at its other extremity of travel, and having a pair of crawler side frame assemblies, each crawler side frame assembly comprising: a central side member extending laterally from and being integral with a supporting frame for the vehicle, said side frame member having at least one track support roller carrying said crawler track in a first direction of travel and track rollers guiding said track in a second direction of travel and at least partially supporting said vehicle on the surface on which it is travelling; a first modular member rotatably carrying at least said idler roller, said first modular member being detachably secured to a first end of said side frame member; a second modular member carrying at least said crawler sprocket, said second modular member being detachably secured to a second end of said side frame member; first and second additional track roller means arranged to be adjacent, respectively, said idler roller and said crawler sprocket; and, mounting means for pivotally connecting said first and second additional track roller means to said side frame member.

2. A track-type vehicle according to claim 1 wherein said track roller means are bogies pivotally connected, respectively, to said first and second ends of said side frame member, each said bogie having rotatably mounted therein a pair of additional track rollers.

3. A track-type vehicle according to claim 2 wherein said mounting means comprises bosses extending from said first and second ends of said side frame member for receiving pins extending, as well, through said bogies thereby pivotally connecting said bogies to said side frame member.

4. A track-type vehicle according to claim 1 constructed as a power shovel and having: an upper frame supporting a body and rotatably mounted on said supporting frame; a stiffleg pivotally connected at its lower end to the body; a dipper handle pivotally connected at its upper end to the upper end of the stiffleg; a dipper pivotally connected at the lower end of said dipper handle; means for raising and lowering said stiffleg about its pivotal connection to the body; and means for swinging said dipper handle about its pivotal connection to said stiffleg, wherein said track rollers receive a substantial portion of the design load of the power shovel, and wherein said first and second additional track roller means are pivotally mounted on the ends of said central side frame member and placed, respectively, so as to bear on said track at those sections of the lower portion of its travel between, respectively, said idler roller and said track rollers and said crawler sprocket and said track rollers so asto carry the remaining portion of the design load of the power shovel.

5. A track-type vehicle according to any preceding claim wherein said first and second modular members form extensions of the respective ends of the side frame member.

6. A track-type vehicle, substantially as hereinbefore described with reference to and as shown in the accompanying drawings.