GB2129768A - Loaders for use in limited space - Google Patents

Abstract

A loader (8) for use in a tunnel or mine haulage in which there is little room for manoeuverability has a bucket (22) mounted on a cantilivered shaft (20) which extends to one side of a single dipper arm (18). The side of the bucket (22) remote from the dipper arm (18) is freely exposed enabling the loading of material which is larger than the bucket. The dipper arm (18) is pivotally mounted on an upright arm (16) which is supported by a ram (26). The dipper arm (18) is movable to discharge the bucket (22) by means of a ram (28) which acts on a toggle linkage (30,32). Orientation of the bucket (22) is maintained by means of a ram (42) which via a chain (44) acts on two drums, one only shown (40), concentrically fixed together, which are connected by means of a second chain (38) to a third eccentrically mounted drum (36). <IMAGE>

Description

SPECIFICATION Loaders for use in tunnels This invention relates to a loader for use in a tunnel or mine haulage in which there is little room for manoeuverability.

In the specification of U.S.A. Patent No. 4188165 there is described a loader which includes a bucket mounted on the end of a dipper arm swinging from a cross member on an upstanding yoke. The dipper arm swings between the upright of the yoke for the bucket to pick up material on one side and deposit it on the other side. In some respects this loader is satisfactory but it suffers from the serious disadvantage that the bucket extends between spaced supports and consequently when it is necessary to move large material which possibly extends beyond at least one side of the bucket the material can be wedged between the bucket and the upright supports or, alternatively, is simply pushed off the bucket. This drawback substantially minimizes the efficiency of the loader.

It is an object of the present invention to provide a loader wherein the aforementioned disadvantage is minimized.

It is a further object of the invention to provide a loaderwhich can under certain conditions handle material of larger dimensions than the bucket.

Another object of the invention is to provide a loader the construction of which requires less material and fewer components than does the loader referred to.

These and other objects of the invention are achieved by a loader which includes a base member, a single upright arm connected to the base member, a single dipper arm which is pivotally connected to the upright arm, a cantilevered shaft which extends from the dipper arm, a bucket which is mounted on the shaft and which extends on one side of the dipper arm, the bucket being pivotal relatively to the dipper arm, and means for moving the dipper arm between a first position at which the bucket is orientated for digging and a second position at which the bucket is orientated for discharge.

The means for moving the dipper arm may include a first link which is pivotally connected at one end to the upright arm, a second link which is pivotally connected at one end to the dipper arm, the free ends of the two links being pivotally interconnected, and a ram which is connected between the upright arm and the two links.

The work "ram" as used in this specification denotes in a first instance an hydraulic ram or similar device but it is also intended to include any other device which is capable of force transmitting movement in each of two opposing directions.

The length of the second link may be adjustable.

The loader may include means for orientating the bucket which includes a first drum which is mounted on the upper end of the upright arm, a second drum which is eccentrically mounted on the cantilevered shaft, a first flexible member the ends of which are fixed to the first and second drums respectively, a third drum which is mounted concentrically with the first drum, a second flexible member one end of which is fixed to the third drum, and a ram which is engaged with the other end of the second flexible member.

The two flexible members may be cables, ropes or the like and preferably are constituted by chains.

The bucket may be releasably connected to the shaft by means of releasable clamps which are located on the rear face of the bucket.

The loader may include means for supporting the upright arm on the base member at a desired angle of inclination relatively to the base member.

The base member is preferably a turntable or the like so that the orientation of the loader can be adjusted.

The loader may be located on a rail or other vehicle.

The invention is further described by way of example with reference to the accompanying drawings in which: Figure 1 is a view from the side of a loader according to the invention, and Figure 2 is an end view of portion of the loader shown in Figure 1.

The drawings illustrate a loader 8 according to the invention mounted on a rail vehicle 10 which may form a terminal portion of a tunnel cleaning train.

The vehicle 10 includes a base member which is constituted by a turntable 12 which is rotatable about a vertical axis 14.

The loader 8 includes a single upright arm 16 which is pivotally connected to the turntable 12, a single dipper arm 18 which is pivotally connected, as may more clearly be seen in Figure 2, to the upper end of the arm 16, a cantilevered shaft 20 which is mounted on the dipper arm at its free end and which extends to the side of the dipper arm remote from the upright arm 16, the shaft being journalled for rotation in bearings, and a bucket 22 which is releasably clamped to the shaft 20 by means of clamps 24 on the rear face of the bucket. The clamps 24 may be constituted by any suitable devices.The advantage of locating the clamps on the rear face of the bucket is that a compact structure is provided wherein the side of the bucket which is closer to the dipper arm may freely move without the repective clamp fouling the dipper arm and wherein the clamp on the other side of the bucket is not in anyway exposed. This enables the bucket to be used for loading material which may be located adjacent a wall or the like.

The rail vehicle 10 includes two hydraulic rams, not shown, for rotating the turntable 12 to slew the loader. The rams are used for centralizing the loader 8 to the position shown in Figure 1.

The upright arm 16 is supported on a hydraulic jack 26 which extends between the vehicle and the arm. This jack is used to vary the inclination of the arm 16 and to retract it to a low level travelling position when the loader is being moved for example in a tunnel.

A hydraulic jack or ram 28 has one end fixed to the upright arm 16 and its other end is pivotally connected to a toggle linkage consisting of links 30 and 32. The link 30 extends between the upright arm 18 and the outer end of the jack 28 while the link 32 extends between the outer end of the jack 28 and a pivot point on the dipper arm 18. The link 32 is telescopic and during normal operation of the loader is locked in an extended position illustrated in Figure 1. The link 32 is telescoped to enable the loader to be dropped into its low level travelling configuration.

The loader includes a bucket orientation control arrangement to hold the bucket in a load retaining position as it is moved from its digging position to its discharge position. The control arrangement consists of a first drum 34 which is rotatably mounted on an axis between the upper ends of the two arms 16 and 18, a second drum 36 which is fixed eccentrically to the shaft 20, and a chain 38 the ends of which are fixed to the drums 34 and 36 respectively. The arrangement further includes a drum 40 which is fixed concentrically to the drum 34, a jack or ram 42 which is mounted on the upright arm 16, and a chain 44 the ends of which are fixed to the drum 40 and to the jack 42 respectively.

When the jack 42 is extended the drums 40 and 34, referring to Figure 1, are moved in a clockwise direction and, under the action of gravity, the drum 36 is also moved in a clockwise direction. The bucket 22 is therefore lowered to its digging position.

Digging i.e. filling of the bucket, is effected by movement of the jacks 28 and 42. As the jack 28 is extended and retracted reciprocating movement is imparted to the dipper arm 18 via the link 32, the jack 42 on the other hand is operated to get the bucket filled as it causes the orientation of the bucket to be changed.

When the bucket is fully loaded the jack 42 is fully retracted and the drums 40 and 34 are rotated in an anticlockwise direction by means of the chain 44.

The chain 38 moves upwardly and the drum 36 is rotated in an anticlockwise direction thereby tilting the bucket upwardly to a load retaining position.

Figure 1 illustrates in dotted outline the position of the bucket 22 and the dipper arm 18 when the bucket has been moved to a discharge position. Movement to this position is achieved by extending the jack 28.

Since the link 30 is fixed to the upright arm 16 the extension of the jack 28 causes the dipper arm 1 8a to move in a clockwise direction around the axle on the upright arm on which the dipper arm is mounted. It should be noted that a cam action is achieved by the fact that this axle is offset with respect to the axis on which the dipper arm is fixed to the upright arm. In the course of this movement the length of the chain 38 between the drums 34 and 36 is effectively varied, because of the eccentric mounting of the drum 36, and because of the cam action referred to, and in so doing the orientation of the bucket is maintained in a load retaining attitude.As the dipper arm is swung passed the upright arm to the discharge position the chain 38 causes rotation of the drum 36 and thereby the bucket 22 so that although the bucket is maintained in a load carrying attitude it is gradually tipped until a stage is reached at which gravity takes over, rotating the bucket into the load discharge position shown in dotted outline in Figure 1. A suitable container, also shown in dotted outline, receives the discharged material.

When the bucket is swung to its digging position the effective length of the chain 38 again varies so that the bucket is again orientated into a load carrying attitude. When the dipper arm reaches the position shown in Figure 1 the jack 42 is again extended to drop the bucket into a digging position.

The loader can be moved to a low level travelling configuration by partially retracting the jack 42 so that the bucket is rotated towards the upper arm, and retracting the ram 26 to lower both the upright arm 16 and the dipper arm 18, unlocking the arm 32 and retracting the jack 28.

A principal advantage of the invention is achieved by the fact that the bucket 22 extends to one side of the dipper arm 18, as shown in Figure 2, with no support being provided on the side of the bucket remote from the dipper arm. This means in the first instance that the bucket can be used for clearing material located adjacent a wall and in the second instance that material which is nominally of greater dimensions than the bucket width can be loaded by the bucket. Such material should of course not extend over the side of the bucket which is adjacent the dipper arm but on the other hand it can extend over the side of the bucket which is remote from the dipper arm. Another advantage of the invention is that use is made of a single suport arm 16 and a single dipper arm 18 and as opposed to the prior art device disclosed in the specification of U.S.A. Patent No. 4188165, a considerable savings in material and components is thereby achieved. Another point is that the width of the bucket can be increased as this dimension is no longer constrained by the spacing of two uprights.

The invention is not limited to the precise constructional details as herein described and for example the drums 34 and 36 could be moved to the right, referring to Figure 2, so that the drum 36 is substantially adjacent the respective side of the bucket. This configuration under certain conditions can increase the stability of the loader. The drums 34 and 40, although referred to as separate units, can be, and preferably are, constituted by different portions of an integral unit and references to these drums are to be construed in this sense.

Claims (6)

1. A loader which includes a base member, a single upright arm connected to the base member, a single dipper arm which is pivotally connected to the upright arm, a cantilevered shaft which extends from the dipper arm, a bucket which is mounted on the shaft and which extends on one side of the dipper arm, the bucket being pivotal relatively to the dipper arm, and means for moving the dipper arm between a first position at which the bucket is orientated for digging and a second position at which the bucket is orientated for discharge.

2. A loader according to claim 1 wherein the means for moving the dipper arm includes a first link which is pivotally connected at one end to the upright arm, a second linkwhich is pivotally connected at one end to the dipper arm, the free ends of the two links being pivotally interconnected, and a ram which is connected between the upright arm and the two links.

3. A loader according to claim 2 wherein the length of the second link is adjustable.

4. A loader according to any one of claims 1 to 3 which includes means for orientating the bucket, the said means including a first drum which is mounted at the upper end of the upright arm, a second drum which is eccentrically mounted on the cantilevered shaft, a first flexible member the ends of which are fixed to the first and second drums respectively, a third drum which is mounted concentrically with the first drum, a second flexible member one end of which is fixed to the third drum, and a ram which is engaged with the other end of the second flexible member.

5. A loader substantially as hereinbefore described with reference to the accompanying drawings.

6. A loader which includes a base member, dipper means pivotally connected to a support on the base member, a cantilevered shaft which extends from the dipper means, a bucket mounted on the shaft and which extends on one side of the dipper means, the bucket being pivotal relative to the dipper means, and means for moving the dipper means between a first position at which the bucket is orientated for digging and a second position at which the bucket is orientated for discharge.