Excavator/loader

Abstract

 57 Earth-moving vehicle which performs the functions of excavator and loader both carried out at the same end of the chassis thereby avoiding duplication of operator seating and controls. The excavator/loader has an operating arm in two sections (6, 9), the first of which (6) may be pivoted into a position which is roughly vertical or inclined rearwardly, for the loading function. The first arm section can be pivoted forwards for the excavating function.

Description

[0001] The present invention is a novel vehicle which combines the functions of excavator and loader and displays important advantages over prior vehicles of this general type.

[0002] A number of vehicles are available which are described variously as excavator/loaders, digger/loaders or backhoe/ loaders and which are designed to perform two main functions. Firstly, an articulated arm at one end of the vehicle, usually the rear, carries a bucket designed to dig below ground level and thereby excavate a trench or hole. This excavator.bucket is normally narrower than the overall width of the vehicle and digs back towards the vehicle. Secondly, the vehicle carries, usually at its front end, a loading bucket for lifting excavated material from ground level upwards into lorries for transport away from the excavation site. The loader bucket is usually at least as wide as the vehicle. Vehicles are also available which perform only one of these functions, or which perform a second function by the provision of special secondary attachments.

[0003] A major difficulty in designing vehicles of this general type is that of providing adequate counter-balancing to balance the effect of the respective operating bucket under load. Thus the unbalancing moment of a full loader bucket at the end of the loader arm has to be off-set by a considerable weight rearward of the adjacent vehicle wheels, especially when the loader is operating on a sloping site and/or at the limits of its reach. This weight must either take the form of heavy ballast built into the vehicle or be provided by the weight of a digger arm and bucket fitted to the other end of the vehicle. This normally means that either the vehicle carries undesirable excess weight in its design or the two functions must be performed at opposite ends of the vehicle.

[0004] A significant disadvantage of such prior excavator/ loaders is that, since the two functions are performed separately at opposite ends of the vehicle, seating and controls have to be provided for the operator facing each end of the vehicle as desired. Such duplication adds to both the cost and dimensions of the vehicle.

[0005] In German Published Patent Application (DOS) No. 3331516, an excavator/loader is illustrated in which both functions are carried out at the same end of the machine. In order to achieve this result, the operating jib is formed in three sections, described respectively as a pre-jib,a main jib and an arm. When the machine is to function as a loader_lthe,main jib and the. arm are set essentially at right angles to each other and remain in that position throughout the loading operation. When the machine is to function as an excavator, the pre-jib and the main jib are set in approximate relative alignment and remain in that position throughout the excavating operation. Controls are provided to achieve the relative movements of the three jib sections, as well as the movement of the jib overall relative to the turntable upon which it is mounted and the movement of the operating bucket relative to the jib.

[0006] It is an object of the present invention to provide an improved excavator/loader in which both functions are performed at the same end of the vehicle, which nonetheless is stable in both modes of operation and which is of a more simple design, and is therefore easier to operate and maintain, than prior forms of excavator/loader.

[0007] The excavator/loader according to the present invention comprises a chassis carrying an articulated operating arm having only two sections, a first arm section supported at one end thereof upon said chassis for pivotal movement relative thereto about a horizontal axis, and a second arm section pivoted to the other end of said first arm section for pivotal movement relative to said first arm section about a horizontal axis, said first arm section being pivotable into a position (the "stowed"position) in which the point of pivoting together of the two arm sections lies above or rearward of the point of pivoting of the first arm section upon the chassis.

[0008] By virtue of the above-defined features, the excavator/loader of the present invention is ableto function, in a stable manner, both as an excavator when the first arm section is in use and also as a loader when said first arm sectbn is in its stowed position. No third arm section is necessary. The duplication of controls associated with a vehicle having the two functions at opposite ends is rendered unnecessary. Thelocating of the first arm section as specified during the loading operation reduces or removes the need for counter-balance weighting in the vehicle. In spite of its diversity, the excavator/loader is a relatively simple vehicle.

[0009] The point at which the first arm section is pivoted to the vehicle (hereinafter referred to as the first pivot point) depends upon other features of the overall design of the vehicle but in general it will normally lie towards the forward end of the vehicle. It is about this pivot point that the arm operates when in its excavating mode. Preferably it is located in the general region of the front end of the wheel-base or other ground-contacting area (as for example when the vehicle is mounted on tracks). Thus, for example, when the vehicle is wheel-mounted, the first pivot point preferably lies in the region of the axis of the front wheels or slightly forward or rearward thereof.

[0010] The first pivot point is preferably set low on the vehicle. Thus, for example, in the case of a wheel-mounted vehicle, the first pivot point preferably lies below the height of the upper circumference of the front wheels of the vehicle. When the overall vehicle geometry does not allow the pivot point to be set between the front wheels or in the corresponding position in the case of a track- laying vehicle, as for example when the operating arm is mounted upon a turn-table, then the pivot point may be set forward of that position, for example low on an overhanging forward extension of the chassis.

[0011] The mounting of the first pivot point is such as to allow pivoting about a horizontal axis, to permit the excavating function to be carried out and also to enable the first arm section to be stowed. In addition, it is advantageous to provide for pivoting of the arm about a vertical axis, to allow the vehicle to excavate to at least a limited extent generally sideways of the vehicle. The mounting at the first pivot point may therefore comprise two separate pivots, of which it is preferred that the vertical-axis pivot is towards the rear.

[0012] If desired, the first pivot point may be so mounted as to be displaceable laterally relative to the length of the vehicle so that the latter may more effectively operate close to an obstruction when in its excavating mode. This may be achieved by mounting the pivot point upon a laterally displaceable carriage or bracket or, less conveniently, upon a turntable.

[0013] In the stowed position of the first arm section, the point at which the latter is pivoted to the second arm section (hereinafter referred to as the second pivot point) lies above or rearward of the first pivot point. In order not unduly to limit the outreach of the arm in its loading function, the second pivot point preferably lies at most only a short distance, measured ina horizontal direction, behind the first pivot point. For example, the horizontal distance may be of the general order of about 25 per cent of the length of the wheelbase or other ground-contacting area of the vehicle. Thus, in its stowed position, the first arm section may be vertical or more preferably may have a rearward orientation, inclined to the vertical by an angle of the order of 5 to 45 degrees, e.g. 20 to 40 degrees, although the angle may be greater if desired.

[0014] The first arm section may be lockable in its stowed position, but need not be so. For example, an electrical, hydraulic or mechanical locking device may be provided so that, when the vehicle is being used in its loading mode, the operating lever which controls the pivoting of the first arm section, or a ram which brings about that pivoting, is rendered inoperative.

[0015] To gain the maximum.benefit of the vehicle of the present invention, it is desirable that the bucket be of a quick-release variety in order that, when the operator changes from an excavating to a digging operation or vice versa, a bucket appropriate to the relevant operation can rapidly be fitted. Thus the attachment fitting may be of a type which permits a quick interchange by conventional manual methods, for example of the nut-and-bolt type. Alternatively, an attachment mechanism of the claw type, optionally operable by the operator without descending from the vehicle, may be preferred.

[0016] The stability of the vehicle, especially in the excavating mode, may be enhanced by the provision of out- riggers or other ground-contacting stabilisers, which may be used merely to brace the vehicle against the ground or may, by jacking, lift two or all of the wheels clear of the ground. Manoeuvrability of the vehicle may be enhanced by providing a skid-steer drive arrangement.

[0017] The invention will now be further described with reference to the accompanying drawings, in which:-

Fig. 1 is an elevation from the side of one form of excavator/loader according to the present invention; and

Fig. 2 is a plan view of the excavator/ loader of Fig. 1.

[0018] More specifically, in Fig. 1 the excavator/loader is illustrated with the vehicle in loading mode shown in full line and with the excavating mode operation shown in chain-dotted'line. In Fig. 2, the excavator/ loader is shown in excavator mode and with outriggers and stabiliser extended.

[0019] The illustrated embodiment is a particularly compact form of the invention. The vehicle has a wheelbase (that is, the horizontal distance between front and rear axles) of about 1.3 metres and an overall maximum dimension, with the operating arm and bucket retracted, of less than 3 metres.

[0020] The illustrated vehicle has front wheels 3, 3 and rear wheels 4, 4 and carries a single, forward-facing seat 5 for the operator.

[0021] The operating arm consists of a first arm section 6, pivoted about a horizontal pivot 7 which in turn is linked to the vehicle body about a vertical pivot 8, and a second arm section 9, pivoted at 10 to the outer end of the first arm section 6. The vertical pivot 8 lies about 0.2 metres to the rear of the axis of rotation of the front wheels 3, 3 and the horizontal pivot 7 lies approximately in line with that axis.

[0022] At the outer end of second arm section 9, a bucket (11 or 12) appropriate to the operating mode is carried. The bucket 11 is the loading bucket and the bucket 12, mounted the opposite way round from bucket 11, is the . excavating bucket. Each bucket is secured to the arm at just two mounting points (as viewed from the side), namely a pivot mounting 13 and a control link mounting 14, by means of which latter the tipping action is transmitted to each bucket. Alternatively, the mounting points 13 and 14 may support an intermediate carrier plate on the end of the operating arm, the alternative buckets then being detachably secured on the carrier plate by a quick-release mounting.

[0023] Operation of the arm and bucket is effected by means of four double-acting hydraulic rams. A first ram 15 controls the pivoting of the first arm section 6 about the first pivot point 7; a pair of rams 16, 16 effect relative pivoting of the arm sections about the second pivot point 10; a fourth ram 17 controls the bucket tipping.

[0024] The excavator/loader is also provided with out-riggers 18, 18 and a rear stabiliser 19, which may be lowered into contact with the ground to give increased stability of operation of the vehicle in the excavating mode.

[0025] As is most clearly shown in Fig. 1, the vehicle may function as a conventional excavator (the chain- dotted feature) by operation of the four rams as desired. However, the design is such that, by operation of the ram 15, the first arm section 6 may be swung upwards and backwards until the pivot point 10 is in the position illustrated in full line, in which position the pivot point 10 lies about 0.3 metres to the rear of pivot point 8. With the first arm section 6 in this position, where it is inclined backwards at an angle of the order of 30 degrees to 40 degrees to the vertical, the vehicle may be used as a conventional.. loader, by operation of the rams 16 and 17 only.

[0026] Thus the vehicle of the present invention is a true excavator/loader, in which the two primary functions may be carried out using a single set of controls by an operator in a single forward-facing seat.

Claims

1. An excavator/loader comprising a chassis carrying an articulated operating arm having only two sections, a first arm section supported at one end thereof upon said chassis for pivotal movement relative thereto about a horizontal axis and a second arm section pivoted to the other end of said first arm section for pivotal movement relative to said first arm section about a horizontal axis, said first arm section being pivotable into a position in which the point of pivoting together of the two arm sections lies above or rearward of the point of pivoting of the-first arm section upon the chassis.

2. An excavator/loader as claimed in claim 1, wherein the rearmost position into which the first arm section is pivotable relative to the chassis is at an angle to the vertical of from 5 to 45 degrees.

3. An excavator/loader as claimed in any of the preceding claims, wherein, in the rearmost position of the first arm section, the distance apart of said two points of pivoting, measured in a horizontal direction, is about 25 per cent of the length of the wheel-base or other ground-contacting area of said excavator/loader.

4. An excavator/loader as claimed in any of the preceding claims, wherein said first arm section is lockable in its rearward position.

5. An excavator/loader as claimed in any of the preceding claims, wherein said first arm section is pivoted thereto in the region of the front end of the wheel-base or other ground-contacting area thereof.

6. An excavator/loader as claimed in claim 5, which is wheel-mounted and wherein said first arm section is pivoted thereto at a point which is below the height of the upper circumference of the front wheels thereof.

7. An excavator/loader as claimed in any of the preceding claims, wherein said first arm section is mounted to permit pivotal movement about both a horizontal and a vertical axis.

8. An excavator/loader as claimed in any of the preceding claims, wherein said point of pivoting of said first arm section upon said chassis is laterally displaceable relative to the length of the latter.

Drawing