GB2206472A - Improvements relating to mower/hedger assemblies - Google Patents

Abstract

A mower/hedger attachment for connection to the excavator arms of an excavator in place of the conventional bucket has a parallelogram type linkage connected between the mower/hedger flail cutter head and the excavator arms to enable the head to be fine adjusted and to float resiliently relative to the excavator arms. A jackable foot in the attachment enables the excavator arms to be jacked across the cross-slide of the excavator for the appropriate transverse positioning of the excavator arms in relation to the fore and aft central axis of the vehicle. <IMAGE>

Description

Improvements Relating to Mower/Hedger Assemblies This invention relates to a mower/hedger assembly, being an apparatus comprising a cutting device for cutting grassy banks and edges and/or for cutting and trimming hedge rows, the apparatus comprising a cylindrical cutting assembly and a mounting there for enabling the apparatus to be mounted on the articulated excavator arms of an excavator vehicle. The apparatus is attached to the excavator arms in place of the conventional excavator bucket so that by manipulation of the excavator arms using the existing arm manipulating hydraulic rams and appropriate hydraulic control system, so the mower/hedger apparatus can be positioned laterally of the vehicle in order to cut grassy banks, edges and hedge rows.

If a mower/hedger apparatus is simply connected to the excavator arms in place of the existing excavator buckets in an excavator of the type commonly used for trenching and excavating work, the arrangement is not entirely satisfactory, because the speed of operation and the conventional layout of the hydraulic arms and rams are not ideal for flail mowing and hedge trimming where a finer and more sensitive speed of positioning movement and control than that available within the existing excavator arms and control, is required.

In accordance with the invention, a mower/hedger apparatus is adapted for attachment to the excavator arms of an excavator vehicle, and comprises a cutting head and a suspension there for, the suspension being attached to the cutter head, and being for attachment to the said excavator arms so as to provide slower speed, and more accurate response, suspension between the excavator arms and the head than is provided by the excavator arms and excavator arm controls.

The cutting head of the mower/hedger apparatus may be of conventional construction and may be adapted to be powered by a hydraulic motor which receives hydraulic fluid from the hydraulic system of the vehicle.

The intermediate suspension preferably is controllable so that the operator can control the cutting head relative to the excavator arms at a slower speed and at a more accurate response which cannot be obtained with normal use of the existing excavator arms.

The suspension may consist of means providing one or more suspension functions. Thus, the cutting head may be adapted for pivotal movement about a central pivot pin to allow angular movement of the cutting head along its length.

Additionally, the suspension means may include a parallelogram type linkage, connecting the head to the excavator arms, with movement means controlling movement of the parallelogram type linkage so that the cutting head by virtue of said linkage can have a degree of movement which is in the nature of a floating movement, and which is independent of the excavator arms. The parallel links may lie on the same axis as the said pivot pin. The movement of the parallel links for the raising and lowering of the cutting head may be effected by means of a hydraulic ram which is coupled to a hydra-cushion bottle which provides resilience enabling the ram to expand and contract in use to give the head the "floating" movement.

Preferably a third control is provided in the form of a means enabling the excavator arms of the vehicle to be jacked across a cross-slide on which the excavator arms are carried, as is conventional practise, and such means may comprise an adjustable leg which can be jacked against the ground in order to cause the mounting supporting the excavator arms to be thrust in one direction or the other across the cross-slide at the rear of the vehicle. The said adjustable leg is adapted to be raised clear of the ground during the normal cutting function of the mower/hedger apparatus.

The positioning of the excavator arms across the said cross-slide in this manner enables the machine to work within a narrower overall width or alternatively by moving the excavator arms to the extreme ends to utilise the maximum reach of the arms for the cutting operation.

An embodiment of the present invention wi 11 now be described, by way of example, with reference to the accompanying drawings, wherein: Fig. 1 is a diagrammatic perspective elevation of the rear of a conventional excavator with excavator arms and a hedger/mower apparatus connected thereto in place of the excavator bucket; Fig. 2 is a side elevation showing how the cutting head of the mower/hedger apparatus is adapted for connection to the excavator arms, the figure showing the cutting head in several positions; Fig. 3 is an end view corresponding to Fig. 2; Fig. 4 is a plan view of a portion of the apparatus shown in Fig. 2; and Figs. 5, 6 and 7 are diagrammatic views showing how the mower/hedger apparatus may be used in several different modes of operation.

Referring to the drawings, in Fig. 1 the rear of a conventional excavator vehicle is indicated by numerai 10, the rear vehicle wheels being indicated by numeral 12. Across the rear of the vehicle is a cross-slide member 14 which has jackable legs 14A with feet 148 whereby the rear of the vehicle can be raised from the ground. On the cross-slide member is carried a king pin mounting 16 which can slide on the slide 14 as indicated by arrow 18.

The king pin mounting 16 carries the excavator arms 20, 22, which are hingedly interconnected at pivot 20A. At the other end arm 20 is hinged to the king pin at pivot 20B, and arm 20 can be pivoted on pivot 20B by means of the ram 21 which is connected between the king post mounting 16 and the arm 20.

A second ram 23 connected at pivot points 23A and 23B to the respective arms 20 and 22 can be extended and contracted so as to control the pivoting of arm 22 relative to arm 20, all of which is of conventional construction and operation.

The arm 22 normally carries at its free end an excavator bucket, but as shown in Fig. 1, the bucket has been replaced by a mower/hedger head 24 which is provided with a flail cutter 26 of cylindrical form and rotatable about an axis 28. A drive motor 30 for driving the flail cutter 26 may suitably be a hydraulic motor which receives hydraulic fluid for the driving of same from the hydraulic circuit of the vehicle 10.

The head 24 is connected to the arm 22 by a suspension assembly indicated generally by 25, so that the whole of the attachment comprising the suspension assembly and cutter head 24 are pivotally mounted on arm 22 for pivotal movement relative to the arm 22 about pivot axis 27.

The pivoting of the attachment is achieved by means of the ram 29 which conventionally is used for the pivoting of the bucket relative to the arm 22.

The direct mounting of the head 24 on the arm 22 has been proposed previously, but it has been found that such an arrangement does not provide the required slow and accurate control of the movement of the cutting head 24 which is required in mowing and hedge trimming operations. The hydraulics which are used for the arms 20, 22 during excavation and trenching work, when the excavator bucket is fitted, are of course satisfactory for that purpose but are too insensitive for hedge cutting and mowing.

The present invention provides that a suitable suspension connects the head 24 to the arm 22 so that the head 24 can be moved in a controlled fashion relative to the arm 22, and one embodiment of the suspension arrangement (25) is shown in Figs. 2, 3 and 4.

Referring to these figures, in Fig. 2 a mounting frame 32 is shown (frame 32 is also visible in Fig. 1), and it is by this frame that the mower/hedger apparatus is connected to the excavator arms. If reference is made to Fig. 4, it will be seen that the frame comprises a square tube member to which are welded mounting plates 34 and 36 by which the mounting 32 is connected to the arm 22 in a fashion enabling articulation of the mounting 32 about pivot 27 so that the mower/hedger apparatus can be manipulated into the positions for example shown in Figs. 5, 6 and 7.

Carried slidably within the mounting 32 is a thrust leg 38 having at its lower end a support foot 40 which can be jacked relatively to the mounting 32 into engagement with the ground or other surface for the jacking of the king pin mounting 16 along the cross-slide 14 (see Fig.

1). In this connection, when it is desired to adjust the position of the king pin mounting 16 on the crossslide 14, a locking means holding the king pin mounting in fixed position on the cross-slide 14 is released, and then the foot 40 is jacked into engagement with the ground or other reaction surface and this jacking movement, depending upon the position of the arms 20, 22 causes the king pin mounting 16 to be jacked along the slide 14 as indicated by arrow 18 until the desired position is reached at which point the reaction force being applied by the foot 40 is removed and the king pin mounting 16 is locked in adjusted position. The foot 40 is then raised clear of the reaction surface.

This method of jacking the 'king pin mounting 16 is conventional and in the more common mode of operation when the excavator arms carry an excavator bucket, the bucket is in fact jacked onto the ground to perform this function.

The mounting 32 has extension plates 42 supporting pivot pins 44 and 46. Pivotally mounted on the pins are pivot links 48 and 50 which in being connected to further pivot pins 52 and 54 on support plates 56 of the head 24 form a parallelogram linkage which can be pivoted up or down from the horizontal position shown in Fig. 2 by means of a pivoting ram 58 connected between mounting plates 56 and plates 42. The ram 58 is fluidically coupled to a hydra-cushion 60 by means of a pipe 62 so that in fact the ram 58 can act as a spring enabling the head 24 to execute floating movements relative to the mounting 32 and in fact relative to the excavator arms 20, 22. The springing or floating effect can be eliminated by the closure of a valve 64 in pipe 62.

The flail cutter 26 is supported from the plates 56 by brackets 64 and 68 which are in turn mounted for pivotal movement on a pivot pin 66 which, as shown in Fig. 3 is located in the central plane of the flail cutter 26. The cutter can therefore articulate as indicated by arrow 68 around the axis of pin 66, although its pivotal movement is limited by rubber buffers or stops 70, 72 carried by the plates 56.

It is also noted from Fig. 3 that the pivot pin 66 also lies in the same plane as the central plane of the parallelogram link arrangement.

The pivoting or rocking movement of the flail cutter 26 about pin 66 can be restrained by the connection of locking straps 74 between plate 56 and the cutting unit 26, appropriate eyes 76, 78 being provided on the respective members for this purpose.

Figs. 5, 6 and 7 show various modes of operation of the arrangement described with reference to Figs. 2, 3 and 4. In Fig. 5, a grassy bank 80 is being mowed by the head 24, the arms 20 and 22 and the head 24 being positioned so that the cutter 26 lies at the same angle as the grassy bank.

In the arrangement of Fig. 6, the arms 20, 22 and head 24 are arranged so that the head can cut the top of a hedge 82, whilst in Fig. 7, the arms 20, 22 and head 24 are arranged so that the cutter 26 can cut the edge of a hedge 84.

The principle of operation in all cases is that the coarse or rough positioning of the cutting head relative to the hedge or grass to be cut is performed using the excavator arms and the manipulating rams of the excavator arms. Slow, fine accurate control of the cutting head is achieved by utilising the ram 58 and the arms 48 and 50. Ram 58 is arranged to have a slow, fine accurate control for the fine adjustment of the position of the head 24 in relation to the surface to be cut. Figs. 5, 6 and 7 show that the head 24 can be finally positioned by the ram 58 in a vertical or horizontal or any intermediate plane relative to the hedge or bank.

The hydra-cushion 13 provides the resilient suspension or floating effect if required, but such effect can be cancelled by closing valve 64.

When it is not required that the head 24 should pivot around pivot pin 66 the pivoting can be eliminated by the connection of links 74 as described, but in an alternative arrangement the link 74 can be locked out of position by lugs or eyes 86 allowing the cutter 26 to swing between the buffer stop limits as described herein. Instead of using the rubber buffers, springs or the like may be used.

It will be understood that the invention can be applied to the various types of excavator which are currently manufactured, and it can also be adapted for any new form of excavator. The mounting plates 34 and 36 will of course be suitably designed depending upon the excavator to which the hedger/mower apparatus is to be attached.

Although the use of a parallelogram type linkage arrangement is described, it is to be pointed out that it is not necessary that the linkage define a prallelogram type arrangement, but an important feature of the invention is the availability of the fine adjustment of the cutting head relative to the excavator arms as the excavator drives forward.

Within the embodiment described, there is provided the ability of the head to float as described, especially when the head is running on the conventional support roller 88 and there is added advantage that the cutter can swing around the axis of pivot pin 66. At the same time the ram can still be precisely controlled in any vertical, horizontal or intermediate position to control the cutting head accurately on the hedge or grass.

An advantageous feature of the embodiment described, is the provision of the leg 38 and foot 40 which can be jacked onto the ground or other surface for the movement of the excavator arms as described herein.

Claims (12)

1. A mower/hedger apparatus which is adapted for attachment to the excavator arms of an excavator vehicle, comprising a cutting head and a suspension there for, the suspension being attached to the cutter head, and being for attachment to the said excavator arms so as to provide slower speed, and more accurate response, suspension between the excavator arms and the head than is provided by the excavator arms and excavator arm controls.

2. An apparatus according to Claim 1, wherein the cutting head comprises a cylindrical flail cutter, and the apparatus is such that it is adapted to be connected to the excavator arms so that when the arms lie in a vertical plane transverse to the fore and aft direction of the vehicle, the axis of the cutter also lies in a vertical plane which may be the same as or parallel to the first mentioned vertical plane, which is transverse to the fore and aft direction of the vehicle.

3. An apparatus according to Claim 2, wherein the cutter is adapted to be pivoted about a central pivot axis lying at right angles to the cutter axis, relative to the excavator arms when connected thereto.

4. An apparatus according to Claim 3, including fixing points to which link means can be connected between the cutter and the remainder of the apparatus for locking out said pivotal movement of the cutter about said central pivot axis.

5. An apparatus according to Claim 3 or 4, including resilient stops limiting the extent to which the cutter can pivot on said central pivot axis.

6. An apparatus according to any preceding claim, wherein the suspension comprises a parallelogram type linkage, connecting the head to the excavator arms, with movement means controlling movement of the parallelogram type linkage.

7. An apparatus according to Claim 6, wherein the movement means comprises a fluid pressure operated ram having a slow, fine accurate control.

8. An apparatus according to Claim 7, wherein the ram is resiliently loaded whereby said linkage has a degree of movement which is in the nature of a floating movement, which is independent of the excavator arms.

9. An apparatus according to Claim 7 or 8, when taken with any of Claims 3 to 6, wherein the said parallelogram type linkage lies in the same vertical plane as the central pivot axis.

10. An apparatus according to any preceding claim, wherein that part of the apparatus which is adapted to be connected to the excavator arms carries a foot which can be caused to be placed into engagement with the ground so that by manipulation of the excavator arms and by the reaction of the foot on the reaction surface the excavator arms can be jacked along the conventional cross-slide at the rear of the vehicle for positioning of the excavator arms at the desired position on said slide.

11. An apparatus according to Claim 10, wherein the foot is carried by a leg which is moveable under power from a stored out of use position which is occupied when the cutting head is in use or during transportation to cause the foot to be engaged with said reaction surface.

12. A mower/hedger apparatus substantially as hereinbefore described with reference to the accompanying drawings.