CHASSIS ASSEMBLY FOR MOBILE MACHINE

This invention relates to a chassis assembly for a mobile machine .

According to the invention there is provided a chassis assembly for a mobile machine, comprising a frame and a pair of wheels laterally adjustably mounted at the opposite sides of the frame, each said wheel being mounted to the frame by an arm pivoted by one end to the frame and supporting pivotally at the other end a member carrying the wheel, and link means being coupled between the frame and said members to maintain the wheel axes substantially parallel throughout the adjustment of the wheels relative to the frame.

The chassis assembly of the invention is particu¬ larly suitable for mounting mechanical diggers, high- lift platforms,cranes and other mechanical working and handling devices. It is constructed in a particularly simple and convenient way to provide a stable working platform during operation of the equipment mounted there¬ on, and at the same time allow the equipment to be easily manoeuvred through restricted access openings, e.g. a doorway, whereby the equipment may be readily moved into a desired working position which is not easily accessible as far as conventional machinery is concerned. For example, the chassis assembly may make it possible to take a machine into a building with a view to performing various functions uch as digging, concrete breaking, sawing, lifting etc.

The above and other preferred features of the inventive chassis assembly will be understood from the following detailed description of some embodiments,

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given by way of example and with reference to the accompanying drawings in which:-

Figure 1 is a schematic plan view of a chassis assembly in accordance with the invention; Figure 2 is a side elevation of the assembly including a support leg;

Figure 3 is a detail view taken in the direction of arrow A in Figure 1 ;

Figures 4 and 5 are schematic views showing in side elevation and plan, respectively, a mechanical digger incorporating a chassis assembly In accordance with the invention.

Figures 6,7 and 8 are views corresponding to Figures 1,2 and 3,. respectively, and showing a modified chassis assembly embodying the invention;

Figure 9 is a front detail view of part of a wheel support plate;

Figure 10 is a detailed side view of the wheel mounting arrangement which permits vertical adjustment of the wheel; and

Figure 11 is a plan view of another chassis assembly embodying the invention.

Referring to Figures 1 to 3 initially, there is illustrated a chassis assembly comprising a main support frame or platform 1 constituted by a pair of upper and lower plates 2,3 rigidly secured together in spaced relationship. The plates 2,3 are similarly shaped being substantially rectangular with the corners removed, Pivotally mounted to the platform adjacent each corner and between the two plates 2,3 is a pair of forks, the forks 4 mounted at one end of the platform (hereinafter _re f _er red to as the front end) being pivoted about vertical axes 5 _? and the forks 6 mounted at the other, rear end of the platform being pivoted about vertical axes 7- Each pair of forks is independently adjustable

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between a folded or retracted position parallel with the longitudinal axis of the chassis, as shown by the upper forks 4,6 in Figure 1, and an out-turned working or operative position inclined to the chassis axis as shown by the lower forks 4 , 6 in Figure 1. Furthermore each pair of forks may be locked in either of these two extreme angular positions by suitable means such as pins inserted through registering holes in the platform and forks, e.g. at the positions indicated by the reference numeral 8. Of course if required the locking means could be arranged to lock the forks at selected intermediate positions also.

The forks are adapted for the connection of res¬ pective outriggers or legs 10 as seen in Figures 2 and 3- Each leg is made in two sectio:..; 11,12 which are telescopically adjustable to allow the length of the leg to be selectively adjusted. At its free end the lower section 12 carries a foot or spud 13 for engaging and penetrating the ground with a view to anchoring the chassis firmly during working operations. The upper section 11 is pivoted to the respective pair of forks about a horizontal axis 14 for movement of the leg in a vertical plane, and an actuating cylinder 15 is connected between points 16 and 17 on the forks and leg section 12, respectively, for rotating the leg about axis 14 between an upwardly inclined inoperative position shown in full line in Figure 2, and a down¬ wardly inclined working position shown in broken line in the same Figure. It will be ^"~ undt ^* rst ood that each of the forks 4-6 is intended to support a telescopic leg 10, but it is not essential that they should do so as will become clear.

The rear forks 6 differ from those at the front of the platform 1 in that the laterally outer fork in each case is extended to provide an arm 18 which

supports pivotally at its free end a bracket 19 for rotation about a vertical axis 20. The bracket in¬ cludes a wheel carrying member provided by an arm 21 formed by a vertical plate which is parallel with the longitudinal chassis axis and supports a stub axle for a ground wheel 22. The bracket also includes a generally triangular top plate 23 and a link arm 24 has one end connected to this plate 23 for pivotal movement about a vertical axis 25. The opposite end of the arm 24 is pivoted about a vertical axis 26 relative to a lug 27 fixedly attached to platform 1 and projecting from the adjacent side of the platform. The line joining the axes 7 and 20 is parallel and equal in length to the line joining the axes 25 and 26 so that the fork IS and arm 24 constitute a system of parallel links which ensure that the plane of the wheel 22 remains parallel to the chassis axis as the forks ό are swung between the folded and working positions . Furthermore as the forks are adjusted between these positions the wheels are automatically adjusted between an extended position as seen in the lower part of Figure 1 and a retracted position as seen in the upper part of this Figure, with the wheel axes being always parallel . When the forks 4.6 are folded in and hence the wheels 21 retracted, the maximum width 2Vv of the chassis may be only about 0.7 metres so that it can be man¬ oeuvred through relatively narrow access passages and doorways which cannot be traversed by machines with a conventional chassis. However, when the forks 4,6 the legs 10 and wheels 21 are moved into their working positions the chassis can provide a very stable support structure for operation of the equipment carried upon it. The chassis is suitable for a wide variety of mobile machinery as mentioned above. In some cases

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the chassis assembly may be modified, for example the rear forks. may not need to be fitted with the legs 10, and legs of different form e.g. vertically extending legs carried on horizontal arms could be used. If required a further pair of wheels 21 could be similarly mounted at the front of the chassis assembly. Other variations are possible and may occur to skilled read¬ ers .

A small excavating machine equipped with the chassis assembly described above is illustrated in

Figures 4 and 5 - frame 30 is mounted on the platform 1 and supports, a motor 31 _} hydraulic pump driven by the motor, a working jib 32 (shown in three different positions in Figure 4) _? a seat 33 for an operator and controls for controlling supply of fluid from the pump to the actuating cylinders of the jib and the out¬ riggers 10. The legs 10 may be lowered to lift the wheels clear of the ground as seen in Figure 4, or the wheels may remain resting on the ground. The frame may be fixedly mounted on the chassis platform 1, alter¬ natively it could be rotatably mounted either for rotation through a limited slew angle, e.g. 120°, of for full 360° slewing movement. The provision of four independently operated outriggers 10 enables the machine to be supported in a horizontal position even when the ground is very uneven. With the rear out¬ riggers lifted clear of the ground the machine can be driven backwards and forwards by appropriate operation of the jib structure. As the wffeels a ays remain parallel the machine is comparatively easy to manoeuvre whatever their adjusted positions. With the outriggers retracted and raised the machine can be easily moved by lifting manually at the forward end and pushing in a manner similar to that used in moving a wheelbarrow. From the foregoing description it will be appreciated

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that the chassis assembly of the invention is intended mainly for small material working and handling machines to make is possible to move them into places having restricted access. The modified chassis assembly of Figures 6-10 is basically the same as that of Figures 1-3 and the same reference numerals have been used to denote corres¬ ponding parts of the two embodiments . Only the modi¬ fications will be described in detail . Fixed to the underside of the platform 1 and projecting forwardly from the chassis platform Is a towing bar 40 fitted at its front end with a conventional ball hitch attachment 41, or the like. The tow bar facilitat.es transport of the machine equipped with the chassis assembly, especially over longer dinstances and when it is de¬ sired not to manoeuvre the machine by hand or drive it with a working jib in the manner described above in connection with Figures 4 and 5-

The forks 6 which carry the wheels 22 are ρro- vided with a series of lockable positions relative to the platform 1, as indicated by the numeral 8. Each wheel is adjustable from an inner position in which the forks extend longitudinally of the chassis to an outer normal working position, as shown In full line for the lower wheel in Figure 6, and then to an outer¬ most towing position as shown in broken line for the lower wheel In Figure 6. The improved articulation allowing the wheels to be moved to the outermost positions enables their axes to be adjusted to a position near the centre of gravity of the machine whereby a better weight distribution on the wheels and towing hitch is obtained for towing and if the machine is operated while still attached to a towing vehicle. Each of the wheels is attached to its support arm 21 by means enabling independent verticle adjustment

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relative to the chassis platform. As seen in Figures 9 and 10 the attachment means comprises a pair of plates 45)46 adapted to be clamped together and having corru¬ gated surfaces. One plate 45 is fixed on the wheel axle pin 47 and the other plate 46 is fixed to the arm 21 and is provided with a vertical slot 48. The inner end of the axle pin 7 is ^* passed through the slot and is threaded to receive a nut 49 (Fig.6) which is tightened to clamp the two plates 45,46 in firm engagement. It will be understood that slackening the nut 49 allows the plate 45 and hence the wheel 22 to be adjusted vertically relative to the plate 46 and then fixed in the adjusted position by re-tightening the nut to bring the corrugated surfaces into locking cooperation. The independent vertical adjustment of the wheels is of advantage when the machine is travelling and working o-n sloping and uneven ground.

The chassis assemblies so far described are pro¬ vided with non-dirigible wheels. It is also possible for the wheels to be dirigible and such an embodiment is shown in Figure 11. The rear wheels 22 in this case are mounted to the chassis platform in essentially the same way as described above with reference to Figures 1 to 3 ₅ but these wheels are fitted with hydraulic motors to be self driven, e.g. by a motor and pump unit mounted on the chassis. The front wheels 5 are similarly mounted to the chassis platform by forks 6 and arms 21, but the inner ends of the arms 24 which control the pivoting movement o ^' d" the arms 21 are not pivoted directly to the chassis platform 1. The plat¬ form mounts pivotally a pair of bell cranks 53 and the inner ends of arms 24 are pivoted to the first lever arms of the respective bell cranks. The second lever arms of the bell cranks are coupled together by a link rod 54- This coupling arrangement between the arms

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24 ensures that the wheel axes always remain substant¬ ially parallel whatever the adjusted position of the wheels 5 relative to the chassis platform. An hy¬ draulic cylinder device 55 is coupled between the chassis platform and one of the bell cranks to control the angular movement of the wheels about the pivots 20 for steering purposes. In the position of the parts shown in full line the front wheels are aligned with the longitudinal axis of the chassis. If the hy¬ draulic ram 55 is extended, for example, the bell cranks will turn clockwise about their pivots and the wheels 52 will be in unison to the angled positions shown in broken line. It will be appreciated that the steering arrangement does not deter from the ability to adjust the wheels 52 laterally in and out relative to the chasis platform in the same manner as for the non-dirigible wheels described above, and the wheel axes are maintained substantially parallel at all times .

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