GB2167362A - Walking excavator - Google Patents

Abstract

A walking excavator including a chassis 11 having a pair of wheels 18, the wheels being movably mounted on the chassis in order to alter their position in relation to the centre of gravity of the excavator. The excavator is shown in its working mode and rests on stabilisers 35, pads 30 and wheels 18. The wheels 18 are mounted on arms 20 pivoted at 21. The arms 20 can be pivoted to lower wheels 18 to the dotted line positions, in which mode the excavator can be walked using the jib 14 and bucket 15. The arms 20 can be further pivoted to bring the wheels 18 closer to the center of gravity of the excavator. In this mode, the excavator can be towed using an extendable tow bar 25. <IMAGE>

Description

SPECIFICATION Walking excavator The present invention relates to a walking excavator.

A walking excavator basically includes a chassis having a pair of wheels and a jib, the jib being used to move the chassis on said wheels when the excavator is on site. Additionally the wheels also enable the excavator to be towed behind a vehicle from site to site. Normally the wheels are attached to the chassis at a fixed position but unfortunately the optimum position for the wheels differs for each mode of use.

Accordingly for towing, the wheels ought to be positioned near the centre of gravity of the excavator in order to provide the correct towing weight at the tow bar. However for the walking mode, it is better for the wheels to be further from the centre of gravity.

According to the present invention there is provided a walking excavator including a chassis having a pair of wheels, the wheels being movably mounted on the chassis in order to alter their position in relation to the centre of gravity of the excavator.

Preferably the wheels are mounted on arms which are pivotally connected to the chassis so as to be movable toward the centre of gravity to reside in a towing position and to be movable away from the centre of gravity to reside in a walking position.

Preferably the wheels are movable beyond said walking position to reside in a working position whereat the wheels project beyond the chassis to preferably act as stabilisers and to preferably enable the chassis to be located as close as possible to the ground.

Preferably each wheel is movable independently so as to enable independent adjustment for height to provide for levelling adjustments to be made particularly during the walking mode over inclined terraine.

Advantageously when the wheels are in said towing position, resilient means are provided between the arms and the chassis to create a suspension. Conveniently resilient means for each arm is in the form of a body of resilient material which is attached to the chassis and against which the associated arm abuts when in its towing position.

Various aspects of the present invention are hereinafter described with reference to the accompanying drawings, in which: Figure 1 is a side view of walking excavator according to the present invention in its towing mode; Figure 2 is a side view of the walking excavator shown in Fig. 1 when in its working mode.

Figure 3 is a part side view of another embodiment according to the present invention; and Figure 4 is a more detailed view similar to Fig. 3.

The walking excavator 10 shown in Figs. 1 and 2 includes a chassis 11 which rotatably supports a cabin 12 which is capable of rotating through 360"C. Attached to the framework of the cabin 12 is a jib 14 which carries a working tool 15. In the illustration the working tool 15 is a digging bucket. The cabin 12 also houses an engine (not shown) for providing pressure to hydraulic fluid which operates the various hydraulic rams used. Conveniently the cabin structure is pivotally mounted on a base 16 to enable it to be tipped to permit easy access to the engine.

The chassis 11 is provided with a pair of ground engaging wheels 18 (only one of which is visible) each of which is rotatably mounted at one end of an associated support arm 20. The opposite end of each support arm 20 is pivotally attached to the chassis 11 by a common shaft 21 which extends through the side members 1 lea of the chassis to be attached at respective ends to respective arms 20.

The shaft 21 is provided with an actuating arm (not shown) and a hydraulic ram (not shown) is connected between the actuating arm and the chassis 11. Accordingly by extending or retracting the hydraulic ram it is possible to rotate shaft 21 and thereby move the position of the wheels relative to the chassis.

Accordingly the wheels 18 may be moved to a towing position as illustrated in Fig. 1 whereat the wheels are located at an inboard position close to the force vector CG acting through the centre of gravity of the excavator and provide sufficient clearance between the chassis and ground for towing. Conveniently the towing bar 25 is telescopically designed so that it may be extended as shown in Fig.

1 for connection to a towing vehicle 28, and so that it may be retracted to a stowed position (as seen in Fig. 2).

On actuation of the hydraulic ram connected to shaft 21, the shaft 21 may be rotated (in the anti-clockwise direction as shown in Fig.

1) to move the wheels 18 to the working position as seen in full lines in Fig. 2. In the working position, the wheels are spaced much further from the force vector CG acting through the centre of gravity and act as stabilisers. Additionally, the wheels 18 permit the chassis 11 to seat upon the ground which assist the stabilising effect of the wheels due to lowering of the centre of gravity of the excavator. Additionally, since the chassis is as close to the ground as possible the maximum digging depth of the jib is achieved.

In order to enable the excavator to walk, the hydraulic ram is actuated to move the wheels to an intermediate position as shown in Fig. 2 by the broken lines. Preferably the wheels are positioned from the working posi tion by the minimum distance necessary, to give sufficient clearance between the chassis and the ground for walking purposes. Thus the wheels 18 are then positioned as far as possible from the centre of gravity for the walking mode.

The chassis 11 is conveniently provided with pads 30 for engaging the ground when the wheels are in the working position. Additionally adjustable stabilisers 35 are provided at the opposite end of the chassis to give stability when the cabin rotates.

Conveniently detachable mudguards 36 are provided which are attached to the base 16 for towing.

A modification of the embodiment described above is illustrated in Figs. 3 and 4 wherein each wheel 18 is mounted on an associated arm 23 which is independently movable between towing and working positions. In Figs.

3 and 4, each arm 23 is pivotally mounted on the chassis 11 by a shaft 21 a which is provided with an actuation arm 40. A hydraulic ram 41 is connected between the arm 40 and the chassis 11 to thereby enable each wheel 18 to be independently moved between its working, walking and towing positions. A resilient body 46 is secured to the chassis 11 at a position so as to be engaged by each arm 23 when each wheel 18 is in its towing position. Accordingly each resilient body 46 acts as a suspension.

Advantageously, each arm 23 is detachably secured to its associated shaft 21 a to enable the arms and wheels to be removed on site.

This is advantageous as it effectively reduces the width of the machine and thereby enables it to pass through narrow openings.

The machine illustrated in Figs 3 and 4 is additionally provided with stabilising legs 50 which are extendable to accommodate for differing levels. With such a construction the wheels 18 may serve to assist stabilisation primarily laterally of the vehicle. Alternatively as shown in full lines in Fig. 3 the wheels 18 may be positioned clear of the ground during the working mode. In Fig. 3 the walking position of wheels 18 has been shown in broken lines.

Claims (6)

1. A walking excavator including a chassis having a pair of wheels, the wheels being movably mounted on the chassis in order to alter their position in relation to the centre of gravity of the excavator.

2. A walking excavator according to Claim 1 wherein the wheels are mounted on arms which are pivotally connected to the chassis so as to be movable toward the centre of gravity to reside in a towing position and to be movable away from the centre of gravity to reside in a walking position.

3. A walking excavator according to Claim 1 or 2 wherein the wheels are movable beyond said walking position to reside in a working position whereat the wheels project beyond the chassis to preferably act as stabilisers.

4. A walking excavator according to any preceding claim wherein each wheel is movable independently to enable independent adjustment for height to provide for levelling adjustments to be made.

5. A walking excavator according to Claim 2 or Claims 3 or 4 when dependent on Claim 2 wherein resilient means are provided between the arms and the chassis to create a suspension.

6. A walking excavator substantially as described with reference to and as illustrated in Figs. 1 and 2 or Figs. 3 and 4 of the accompanying drawings.