WO1991014835A1

WO1991014835A1 - Multipurpose attachment for excavators and the like

Info

Publication number: WO1991014835A1
Application number: PCT/GB1991/000445
Authority: WO
Inventors: Peter Arthur Taylor Hawkins
Original assignee: Hawkins Peter A T
Priority date: 1990-03-24
Filing date: 1991-03-25
Publication date: 1991-10-03

Abstract

A multipurpose attachment for a powered arm (3) of an excavator, loading shovel or the like (1) comprises one or an opposed pair of tool carriers (11, 13), a pivotal connection (15) to the arm, rams (5, 7) for pivoting the tool carriers on the arm, and many different tools or sets of tools. The tool carriers and the tools are provided with compatible mountings so that the tools are readily interchangeable on the tool carrier. Tools include grapples (41, 101, 102), concrete crushing teeth (61, 71, 121), buckets (81), pipe grabs (91), pallet tines (101), rakes (118) and a dozer blade (116), all useful for demolition and site clearance work. The need for many costly dedicated attachments for the excavator is avoided. The tool carrier can be formed from an assembly of plates (20, 21, 22, 23, 24, 27, 28, 29; 50, 53, 54, 55, 57, 58, 59) first slotted together and then welded, and can include spaced apart cross members (23, 24; 53, 54) with channels between them in which the tools can be located and secured by quick release pins.

Description

MULTIPURPOSE ATTACHMENT FOR EXCAVATORS AND THE LIKE

This invention relates to a multipurpose attachment for excavators, backhoes, front and rear end loaders, and similar vehicles and machines. Typically, such excavators and the like are provided with a powered, and usually articulated, arm or boom. A variety of different implements, or tools, can be fitted to the working end of this, remote from the machine.

Taking a typical excavator as an example, a digging bucket is mounted pivotally at the end of a powered and articulated arm. The arm carries a hydraulic cylinder whose piston is connected to the bucket by a crowd link, for pivoting or crowding the bucket^'during the digging action.

If a different function is needed, the bucket is removed, and a new implement is fitted in its place. This new implement might be a grapple, a clamshell opening bucket, a concrete drill, routing tines, or one of many other kinds of tool. In all cases the first implement must be detached from the excavator boom and from the hydraulic ram or linkage which controls the attitude of the implement; and the replacement implement must be fitted in its place.

The present invention has for one object to provide alternative means for providing a variety of implements. The term "tool" is used herein to refer to all kinds of implements. Preferably, such means allow different tools to be exchanged simply and speedily, and reduce the cost of providing a broad range of implements for use on an excavator or the like.

In accordance with the invention a multipurpose attachment for a powered arm of an excavator or the like comprises a tool carrier, means for attaching the tool carrier by a pivotal connection to the arm, means for pivoting the tool carrier with respect to the arm, and a plurality of differing tools or sets of tools; wherein the tool carrier and the tools are provided with compatible mounting means, whereby selected ones or sets of the tools are readily mountable on the tool carrier in a working disposition, and are readily demountable therefrom for replacement by others of the said tools.

The means for attaching the tool carrier to the excavator arm or boom can most simply be a connection comprising a pivot pin passing through a bush in the working end of the arm, and through a bush in the tool carrier on each side of the arm. Many alternatives are possible.

The means for pivoting the tool carrier can be a conventional hydraulic ram carried on the excavator arm, acting directly or through a linkage on the tool carrier; or any other suitable means.

The differing tools will be further described below, but examples requiring a single tool carrier include routing tines, pallet tines, an excavator bucket, a rake, and a dozer blade.

The compatible mounting means on the tool carrier and on the various tools may comprise locating means and securing means. The locating means may comprise a tongue or like projection on the one and complementary receiving means on the other; practically, and preferably, the projections are on the tools, and the receiving means are on or in the tool carrier. The securing means are desirably quickly and simply released or engaged, and are often pins passing through aligned holes or bushes in the respective tools and in the tool carrier. Bolts, hooks or any other desired means may also be used.

The tool carrier may comprise a frame having an inner and an outer cross member spaced apart parallel to the pivot. The term "outer" here refers to the side of the .tool carrier to which the hydraulic ram, or other means for pivoting the tool carrier, is attached, and "inner" refers to the opposite side. The projections on the tools ay then pass between and be supported by these cross members, the tools themselves extending outwardly of the tool carrier in their working dispositions.

In the case of a single tool, such as a dozer blade for example, a plurality of mounting points may be provided for more secure mounting of the tool on the tool carrier. Thus two or more receiving means may be spaced apart, preferably across the tool carrier, for receiving a like number of tongues or projections on the tool. In the case of a set of tools, such as tines of various kinds, each individual tool may be mounted at its own single mounting point on the tool carrier. Preferably, a plurality of spaced apart mounting points on the tool carrier serve either for a plurality of tools in a set, or for a plurality of connections to a single tool, according to the tool or set of tools being mounted on the tool carrier.

In a further aspect of the invention, two opposed tool carriers as aforesaid are combined into an attachment in the form of a pair of cooperating jaw members. The two tool carriers may share a single pivotal connection to the arm or boom, or may be separately mounted on the arm or boom at mounting points that are spaced apart.. Each may be provided with means for pivoting it, normally by a ram connected to the outer side of the tool carrier (relative to the jaw) and mounted on the excavator or loader arm. Alternatively, one tool carrier may be pivotally mounted in accordance with the invention, while the other remains fixed to the arm or boom.

This enables the benefits of the invention to be extended to implements or tools which require two cooperating mounts, as in various types of grab and grapple, and particularly in demolition grapples. Demolition grapples are useful in the demolition of buildings and the clearance of building sites, as well as handling, sorting and loading scrap and timber. Many kinds of tool or implement are used for demolition purposes. Those that are normally fitted as hydraulically powered attachments on excavators, loading shovels or the like include grapples of various designs, which typically range from clamshell bucket grabs with no teeth or short teeth to skeleton clamshells with long opposed tines. While tines can cope with the majority of materials encountered in building demolition, concrete, especially reinforced concrete, must normally be dealt with by means of a specialised concrete breaking attachment.

By using a multipurpose attachment in accordance with the present invention, a demolition grapple is also capable of breaking and crushing concrete, thereby reducing the number of different machines or attachments required.

This is achieved by the use of a set of concrete crushing teeth as the tools to mount on one, and preferably both, jaw members formed by two opposed tool carriers.

In a preferred embodiment, a demolition grapple of this kind comprises a jaw having two opposed jaw members each mounted on a pivot; each jaw member including an inner and an outer cross member spaced apart parallel to the pivot; means for mounting tines in each jaw member between and supported by the cross members and extending outwardly of the jaw member; means for mounting inwardly facing teeth on the inner cross member in each jaw member; and tines and teeth adapted to fit said mounting means. The two jaw members may share a single common pivot or may have separate spaced apart pivots.

The tines and the teeth are desirably readily demountable from and remountable in the jaws, so that the grapple can be converted between a simple grapple and a concrete breaker by appropriate substitutions of tines and teeth. For economy of construction, the tines and the teeth may utilise the same mounting means, such as locating means and securing means. The means for mounting the teeth may comprise means for locating each tooth on the inner cross member, and means for securing the so located tooth in position thereon.

The inner cross member may form an inner lip of the jaw member, and the outer cross member may form an outer lip of the jaw member. The inner cross members in the two opposed jaw members may be so formed and positioned as to present crushing surfaces towards each other on closure of the grapple jaw. In this way, small or broken materials can be further crushed between the lips of the grapple.

The crusher teeth may be provided with claws adapted to locate the teeth on the inner cross member.

The jaw members may each be provided with channels for laterally locating.either tines or teeth, and pins or the like for securing and retaining the tines or teeth in the respective channels. A tooth may be mounted on an inner cross member by loading into a channel towards the member from the pivot side of the jaw, until mounted on the cross member, and then securing the tooth; while a tine may be mounted between the inner and outer cross members by loading into a channel towards the pivot from outside the jaw, before securing it in position.

Alternatively, the teeth for mounting in one jaw member may be provided on a removable beam extending across the tool carrier. There may still be claws adapted to locate the teeth, by way of the beam if required, on the inner cross member. The beam may however be secured to the tool carrier by pins, bolts or the like elsewhere than in the channels.

An advantage of such a beam is that it can be extended laterally on one or both sides of the jaw, and can be provided with teeth where so extended, so that the narrow upright concrete structures can be crushed, such as posts, or the ends of walls. In the case of an attachment which comprises two tool carriers for replaceable tools, in which both tool carriers are.pivotal ly mounted, but have pivots that are spaced apart, further advantages can be realised. If each tool carrier is provided with its own ram, the tools carried in the tool carriers can not only be moved towards and away from each other, but can also be moved across each other with a sliding or grinding action. This can be used for various purposes, and in particular for more readily breaking concrete pieces between toothed grinding tools.

Other tools in the nature of grapple members for mounting in jaws formed by opposed tool carriers include clamshell halves, callipers, pipe grabs, shears and the like. In general, ^"the invention can be applied to an extremely wide range of tools in such diverse fields as materials handling, agriculture, forestry, demolition, land clearance and others.

Clamshell buckets are usually opened and closed by a hydraulic cylinder acting simultaneously on each half through a l.inkage. By this invention, a novel clamshell bucket is provided in which each clamshell half is mounted independently. Each clamshell half can be provided with a pair of mounting arms having projections to be received in a tool carrier.

The invention also provides a novel pipe or pole grab in which each tool carrier forming the jaw members carries a tool extending laterally of the jaw and having a concavity presented towards a corresponding concavity oh a corresponding tool on the opposite tool carrier. By articulation of the jaws as a unit on the excavator boom, a pipe or pole, such as a telegraph pole, can be picked up from the ground, swung into a vertical position, and lowered into a prepared pit, in one action of the machine.

The invention further includes a novel grab comprising at least two tines in one tool carrier of the jaw and at least two tines in the other tool carrier of the jaw, in which the said tines in one tool carrier are connected by a web, and are so located and spaced that they pass just between the said two tines in the other tool carrier. This grab has an improved pick-up of loose material. Preferably, the two tines on the other tool carrier, i.e. those located and spaced just outside the tines joined by the web, are themselves provided with outwardly extending webs or fins, to further benefit the handling of loose materials.

Each tool carrier may be fabricated from an assembly of structural plates having interengaging tongues and slots, whereby a skeleton framework can be assembled prior to welding to effect a permanent mounting frame for the tools. Each tool carrier may include. an inner cross member in the form of a plate in tongue and slot engagement with respective side plates of the tool carrier.

Receiving channels or sockets for tongues or projections to make up the mounting means for the various tools on the tool carrier may be provided within the tool carrier structure.

It will be appreciated that it is known to provide for replacement tines or teeth in certain attachments for use with excavators and like machines. This is for the purpose of renewal or repair, with replacement of worn or broken tines or teeth by new or^' reconditioned ones of the same. The present invention is, in contrast, concerned with providing at least two and preferably three or more distinct kinds of tool on one multipurpose attachment, by the provision of, amongst other things, compatible mountings throughout.

The invention is illustrated by way of example in the accompanying drawings, in which:

Figure 1 illustrates an excavator provided with a grapple comprising two opposed tool carriers fitted with tines; Figure 2 is a side elevation of a demolition grapple of the kind illustrated in Figure 1;

Figure 3 is a rear elevation (as viewed from the right of Figure 2) of the front jaw member of the grapple (the jaw member on the left of Figure 2);.

Figure 4 is a rear elevation of the rear jaw member of the grapple;

Figure 5 is a part sectional view of the rear jaw member, taken on the line V-V of Figure 4, showing the mounting of a tine;

Figure 6 is a similar view to Figure 5 showing a concrete crusher tooth mounted instead of the tine;

Figure 7 is a perspective view of a beam carrying a set of. concrete crusher teeth;

Figure 8 is a side elevation of a jaw fitted with a pair of beams as shown in Figure 7;

Figure 9 is a side elevation of a jaw fitted with a clamshell bucket, shown open;

Figure 10 is a perspective view of one of the clamshell halves;

Figure 11 is a side elevation of a pair of pipe grabs for mounting in a jaw according to the invention;

Figure 12 is a plan view of the pipe grabs shown in Figure

11; Figure 13 is a perspective view of the tools for a webbed grab, positioned as if the grab were open;

Figure 14 is a perspective view of a single pallet tine for installation in a tool carrier of the invention;

Figure 15 is a rear elevation of a combination rake and dozer blade tool, in its vertical or rake orientation;

Figure 16 is a side elevation of the rake/dozer blade of Figure 15;

Figure 17 is a side elevation of an alternative grapple attachment to that shown in Figure 1, in which one tool carrier is pivoted on a boom and another is fixed and separated from the first; and

Figure 18 is a side elevation of a further arrangement in which the two tool carriers of Figure 17 are both pivoted, at the same separated locations on the boom, and the resulting attachment is provided with a pair of concrete crushing and grinding tools.

Figure 1 gives a general indication of the field of the invention. A mechanical excavator vehicle 1 is provided with a hydraulically powered articulated boom 2 which ends in an arm portion 3 adapted to carry a working attachment 4, in this case a grapple, by a pivotal mounting 15.

The arm 3 conventionally carries a crowd ram 5 which pivots the attachment through a crowd link 6. In this case, the attachment comprises two tool carriers 11 and 13, forming the jaw members of the grapple. Only- the front tool carrier 11 is moved by the crowd ram and crowd link. A secondary hydraulic ram 7 is provided on the underside of the arm 3 for independently pivoting the rear tool carrier 13. The general construction of the grapple is as a skeleton double jaw consisting of a front jaw member 11 and a rear jaw member 13 mounted on a common pivot 15. The two opposed jaw members are constructed from high tensile abrasion resistant steel on similar principles, but differ in detail.

As will be apparent from Figures 2 and 3, the front jaw member 11 comprises two side plates 20 joined by a number of cross pieces all parallel to the pivot 15. In order of increasing distance from the pivot, the cross pieces are a triangular section hollow box beam 2.1, a T section beam 22, an inner cross member 23, and an outer cross member 24.

Upper interior bracing plates 27 connect the pivot to the triangular box beam 21; median interior bracing plates 28 connect the triangular box beam to the T section beam 22; and lower interior bracing plates 29 connect the T section beam to the inner and outer cross members 23 and 24.

Side plates 20.and upper bracing plates 27 carry bushes 26 for a pivot pin.

The triangular box beam 21 is fabricated from three plates each formed with a tongue 31 in each end: the tongues are located in slots cut in the side plates 20, and the beam passes through triangular cut-outs in upper bracing plates 27. The T section beam 22 is fabricated from two plates similarly provided with end tongues 32 which are located in slots in side plates 20. This form of construction simplifies assembly and eliminates the need for careful ^'measurement and/or the use of jigs; the basic skeleton can be assembled by simply slotting these components together, and fabrication is completed by welding throughout.

The inner and outer cross members 23 and 24 are in tongue and slot engagement with the side plates 20. In this instance, referring to each end of the inner cross member 23, a narrow tongue 34 with a broadened T head 35 fits into a slot 36 cut into the inner edge of side plate 20. Head 35 prevents the cross member from pulling out towards the opposite side of the jaw member. This assists in holding the assembly together before welding, as referred to above. At the welding stage, a U shaped collar 38 is passed around head 35 and is welded to the head and to the side plate, to further secure the cross member in slot 36. Outer cross member 24 is secured identically on the outer edges of side plates 20.

Three tines 41 are mounted in the jaw member, extending outwardly from three channels formed, respectively, on either side of-.the jaw member between a lower interior bracing plate 29 and a side plate 20, and centrally between two lower interior bracing plates 29. The tines are located by these plates and are supported by the inner and outer cross members which pass over and under the three channels, and are retained in position by pin 42, which can be readily removed and replaced.

Turning now to the rear jaw member 13, shown in Figures 2 and 4, this is most conveniently described by reference to its significant differences from the front jaw member 11. It is narrower, having only two tines 41, adjacent each side plate 50, in channels formed between the side plates and lower interior bracing plates 29. Only^" a single central lower interior bracing plate 29 is used, as no central channel is needed to locate a central tine.

The tines are retained by a removable pin 51, and are supported against inward or outward movement by inner and outer cross members 53 and 54 respectively, which are built into jaw member 13 in an identical manner to the corresponding cross members 23 and 24 in front jaw 11.

Upper interior bracing plates 27 carrying the inner bushes 26 in front jaw member 11 have no direct counterparts in the rear jaw member 13. However, the side plates 50 are shorter and are extended to the pivot 15 by thicker top side plates 55 welded to the side plates 50 and to triangular hollow section cross beam 57. The top plates 55 carry pivot bushes 56 which just fit between the respective pairs of pivot bushes 26 on the front jaw member.

The counterparts to the median interior bracing plates 28 of the front jaw member are a pair of backplates 58 provided with bushes 60 for a pin for connection to a hydraulic ram, to open and close the rear jaw member. Backplates 58 bridge triangular cross beam 57 and an angle section cross beam 59 made up of two plates analogous to the T section cross beam 22 in the front jaw member.

The front jaw member will also be provided with plates and bushes (shown chain dotted) for a second ram, but this is a variable fitting and so is not normally built into the jaws until the details of the excavator, backhoe or loading shovel to which it is to be attached are known. Generally, the grapple may be attached to an excavator arm in this way: it will be carried by pivot 15 directly on the excavator arm; a supplementary hydraulic ram will be mounted below the arm and will power rear jaw member 13 by connection at bushes 60 on backplates 58; and power from a conventional crowd ram over the excavator arm will be transmitted through a crowd link to the and bushes mounted on the front jaw member 11.

Among other variations not shown in the drawings is the number of tines that may be provided for. Each jaw member may be constructed to hold any number of tines and teeth; and not all need be installed at any one time.

Figure 5 illustrates clearly how the tines 41 can be demounted from and remounted in the rear jaw member 11; the tines in the front jaw member can be removed and replaced similarly. The tine shown is supported between inner cross member 53 and outer cross member 54, and retained by pin 51. Arrow A shows the direction of removal and replacement, after, removing pin 51. The tines are .removed outwardly It will be appreciated that jaw members 11 and 13 form mounting frames, or tool carriers, for replaceable tools which are represented by tines 41.

Figure 6 corresponds to Figure 5 but shows a crusher tooth 61, for breaking and crushing reinforced concrete, in pace of tine 41. The upper end of tooth 61 lies in the same channel that located the tine, that is to say the channel between bracing plate 29 and side plate 50, and is secured by retaining pin 51 in a similar manner. However, the body of the tooth is angled inwardly over the inner cross member 53, except for a claw 62 which forks away from the tooth body and extends a short distance over the outer face of the inner cross member, thereby mounting the tooth securely on the inner cross member for as long as pin 51 remains in position.

Tooth 61 is provided with inwardly facing hardened points 64 at that portion of the tooth body that overlies the inner cross member, thus assuring maximum support for the tooth during crushing operations.

Arrow B shows the direction of removal and replacement of the teeth, after removal of pin 51. It can be seen that the teeth are demounted and remounted from the upper or pivot side of the jaw members.

As a rule, for breaking reinforced concrete, a single tooth on one jaw member is used between two teeth on the opposite jaw member. Accordingly, while both tines on the rear jaw member would be replaced by teeth when concrete breaking is intended, all three tines on the front jaw member would be demounted but only one tooth would be installed, in the centre position. This maximises the . bending moment applied to the materials to be crushed or broken. When the jaws are partially opened from the full closed position 5 shown in Figure 2, the opposite inner cross members 23 and 53 cooperate as broad crusher plates and present crushing surfaces towards each other for pulverising less robust materials on closure of the grapple jaw.

•JO Figures 7 and 8 show a variation in which the concrete crusher teeth are integral with a beam 70 which extends transversely across the inner face of each jaw member, and beyond the jaw members on either side.

15 Beam 70 carries crusher teeth 71 at spacings corresponding to the channels in the corresponding jaw member 11 or 13 in which the grapple tines are located. The same crusher teeth pass below the beam to its other side where they are formed as claws 72, and locate the beam on the tool carrier by entering the said channels, o passing behind the inner cross member 23 or 53.

Longer claws could be provided, to enable the beam to be secured by the same pins as secured the tines, but in the illustrated embodiment a single securing point for each beam is provided by 5 bolts 76, which fasten the beams directly to the inner faces of their tool carriers through holes 75 in plates 74.

The beams project beyond the jaws on either side and terminate in ^"further teeth ^"77, which enable the converted grapple to be placed 0 alongside a narrow upright structure, such as, a reinforced concrete lamp post, to nibble the concrete off the steel reinforcing bars.

The differing tools extend beyond grabs and concrete crushing teeth. Figures 9 and 10 show how simply a clamshell bucket can be 5 formed and operated by means of the invention. The clamshell 80 is formed of two similar halves, differing only in the spacing of the interior mounting arms 82 to correspond with the tine channel spacings in the tool carriers constituting the two jaw members. Arms 82 are secured in the respective channels by pins 42 and 51, as for the grab tines.

Figure 10 illustrates how the arms 82, which are cranked away from the opposite clamshell half within the bucket, are connected to the sheet steel of each half through a reinforcing plate 85.- There are further reinforcing plates 86 at the working edges of the clamshell.

The arms 82 can be located at any desired position in or on the clamshell, or in or on any other bucket, provided compatible mounting means are provided on the tool carriers.

Figures 11 and 12 illustrate a pair of pipe grab halves, approximately in the relative positions that they would be in if mounted in a jaw comprising tool carriers according to the . invention.

Essentially, each pipe grab half consists of two downwardly extending members 91 and one laterally extending cross member 92, welded together. Each is given a concave profile 93, 94, for gripping a cylindrical object such as a round pipe, a log, or a telegraph pole. The upper parts of the members 91 are dimensioned to fit the standard tine mountings on the tool carriers already described, and to be retained by pins, as before. The cross members 92 can-be used to pick up, as an example, a telegraph pole, that is lying horizontally alongside the jaws. After lifting the pole, the jaws can be pivoted away from the excavator through 90°, lifting the pole upright. It can then be lowered into a pit prepared for it. The tools shown in Figure 13 convert the attachment into a grab adapted for loose materials. Two tines 101 are intended to be mounted in the jaw member 13 so that, on closing the jaws, they pass just between two tines 102 intended to be mounted in the outer channels of jaw member 11. Each tine has an upward extension 104 within the jaws to extend the grasp of the grab. While this arrangement as so far described is in fact a perfectly acceptable alternative design of grab to that shown in Figures 1 to 5, Figure 13 shows the use of a web 106 between the two closest tines 101, and corresponding side webs or fins 107 on the outer s.ides of the tines 102. The web and fins augment the ability of this grab to pick up loose materials, such as light scrap metal.

The numbers and shapes of tine, and whether or not webs or fins are used, are all within the scope of the invention.

Figures 14, 15 and 16 show tools suitable for mounting on one tool carrier only. In Figure 14, a single pallet tine 111 is mounted to the tool carrier by a projecting tongue or arm 112. Pallet tines will be fitted in sets of two, or possibly more, spaced apart across the tool carrier.

If the channel separation in a given tool carrier does not correspond to the desired pallet tine separation, cranked or offset pallet tines may be used. Moreover, the pallet tines can be fitted to face either forwardly or backwardly as desired, and if fitted in a jaw, in either tool^' carrier.

Figures 15 and 16 show a combination rake and dozer blade. Again, mounting is by a pair of correctly spaced projecting tongues or arms 115. These are welded to a dozer blade 116, reinforced by a plate 117. Vertically oriented as shown, the tool is a rake, by virtue of the two rows of downwardly extending teeth 11-8 carried on the blade 116. However,- by pivoting the tool carrier to a horizontal orientation, the blade 116 becomes vertical and can be The numbers and positioning of teeth 118, and indeed the teeth themselves, are optional. Alternatively, they can be replaced by other kinds of raking, tillage, harrowing or scarifying device, such as spring tines.

Figures 17 and 18 show examples of the use of spaced apart mounting points for the two tool carriers 11, 13. In each case the tool carrier that comprises the front jaw member 11 is mounted as before on the pivot 15 at the tip of arm 3, but the rear jaw member 13 is mounted under the arm at mounting point 125. This is essentially a pivotal mounting, but while in Figure 18 the rear jaw 13 is free to pivot under the control of ram 7, in Figure 17 it is braced by strut 127 so as to be rigid with the arm 3.

Figure 17 shows a grapple in which only one jaw member, the front jaw member 11, moves. However the rear jaw member 13 of the grapple could equally be pivotally mounted under the control of ram 7 as in Figure 18. In either case, the spread of the open grapple is greater than in a grapple with a single common pivot, as shown in Figure 1. The position of the second mounting point 125 can be chosen at will.

Figure 18 shows a concrete crusher, in which crusher teeth 121, similar to teeth 61 (Figure 6), are mounted in each of the two opposed tool carriers 11, 13. Ram 5 powers front jaw member 11 with an inward force of about 50 tonnes, and ram 7 powers rear jaw member 13 with an inward force of up to about 100 tonnes. The hydraulic supply to ram 5 is provided with a pressure relief valve. The arrangement is such that when the full force of ram 7 is applied to rear jaw member 13, front jaw member 11 is pushed forward by it, and when the force of ram 7 is relaxed, the force of ram 5 is sufficient for front jaw member 13 to push rear jaw member 11 back. Because of the.spaced apart pivot points 15 and 125, this results in a relative sliding or grinding action between the two ^• jaws. The spacing of the two pivots also means that a given piece of concrete can be located closer to the pivot axes than if the pivot axes were coincident. These two factors each enhance the performance of the attachment in breaking concrete pieces.

I have found that a multipurpose attachment of this kind can successfully be used as a demolition grapple to pull down walls, crush concrete, load lorries and skips, sort rubble, lift and break concrete paving, and load and sort scrap metal. Normally, several machines might be required for these jobs, including especially a separate purpose-built concrete crushing tool. The grapple illustrated and described can however quickly be converted into a - concrete crusher, by replacing the tines with the teeth as described, and can then be used to break up steel reinforced concrete beams, remove the concrete lumps from the steel reinforcing rods, separate and pulverise the concrete, and recover steel scrap for reprocessing. The performance can be further enhanced by .increasing the number of differing tools that can be mounted on the tool carriers.

Claims

1. A multipurpose attachment for a powered arm of an excavator, loading shovel or the like comprising a tool carrier, means for attaching the tool carrier by a pivotal connection to the arm, means for pivoting the tool carrier with respect to the arm, and a plurality of differing tools or sets of tools; wherein the tool carrier and the tools are provided with compatible mounting means, whereby selected ones or sets of the tools are readily mountable on the tool carrier in a working disposition, and are readily demountable therefrom for replacement by others of the said tools..

2. A multipurpose attachment according to claim 1 wherein the compatible mounting means on the tool carrier and on the tools comprise locating means and securing means, and the locating means comprise a tongue or like projection on one of the tool carrier or the tools and complementary receiving means on the other.

3. A multipurpose attachment according to claim 1 or claim 2 wherein the tool carrier comprises a frame having an inner and an outer cross member spaced apart parallel to the pivot.

4. A multipurpose attachment according to claim 3 wherein the mounting means comprise projections on the tools which pass between and are supported by the cross members, the tools extending outwardly of the tool carrier in their working dispositions.

5. A multipurpose attachment according to any one of the preceding claims, wherein the mounting means comprise a plurality of spaced apart mounting points on the tool carrier for either a plurality of tools in a set, or a plurality of connections to a single tool, according to the tool or set of tools being mounted on the tool carrier.

6. A multipurpose attachment according to any one of the preceding claims, wherein a second tool carrier provided with compatible mounting means for the said tools is mounted on the arm opposed to the first tool carrier, and the first and second tool carriers thereby constitute a combined attachment in the form of a pair of cooperating jaw members.

7. A multipurpose attachment according to claim 6 wherein the two tool carriers share a single pivotal connection to the arm.

8. A multipurpose attachment according to claim 6 wherein the two tool carriers are separately mounted on the arm at .mounting points that are spaced apart.

9. A multipurpose attachment according to any one. of claims 6 to 8 wherein each tool carrier is provided with means for pivoting it with respect to the arm.

10. A multipurpose attachment according to any one of claims 6 to 8 wherein the first tool carrier is pivotally mounted while the second is fixed to the arm.

11. A multipurpose attachment according to any one of claims 6 to 10, wherein the plurality of different tools or sets of tools include grapple tines and a set of concrete crushing teeth.

12. A multipurpose attachment according to claim 11 in the form of a demolition grapple comprising a jaw having two opposed jaw members each mounted on a pivot; each jaw member including an inner and an outer cross member spaced apart parallel to the pivot; means for mounting tines in each jaw member between and supported by the cross members and extending outwardly of the jaw member; means for mounting inwardly facing teeth on the inner cross member in each jaw member; and tines and teeth adapted to fit said mounting means.

13. A multipurpose attachment .according to claim 12 wherein the means for mounting the teeth comprise means for locating each tooth on the inner cross member, and means for securing the so located tooth in position thereon.

14. A multipurpose attachment according to claim 13 wherein the teeth are provided with claws adapted to locate the teeth on the inner cross member.

15. A multipurpose attachment according to any one of claims 12 to 14 wherein the inner cross member forms an inner lip of the jaw member, and the outer cross member forms an outer lip of the jaw member, and the inner cross members in the two opposed jaw members are so formed and positioned as to present crushing surfaces towards each other on closure of the jaw.

16. A multipurpose attachment according to any one of claims 12 to 15 wherein the jaw members are each provided with channels for laterally locating either tines or teeth, and pins or the like for securing and retaining the tines or teeth in the respective channels.

17. .A multipurpose attachment according to claim 12 wherein the teeth for mounting in one jaw member are provided on a removable beam extending across the tool carrier and extended laterally on one or both sides of the jaw, and provided with teeth where so extended.

18. A multipurpose attachment according to any one of claims 6 to

17, wherein the plurality of different tools or sets of tools include clamshell bucket halves.

19. A multipurpose attachment according to any one of claims 6 to

18, wherein the plurality of different tools or sets of tools include a pair of pipe or pole grabs adapted to extend laterally of the tool carriers, each having a concavity presented towards a corresponding concavity on a corresponding tool on the opposite tool carrier.

20. A multipurpose attachment according to any one of claims 6 to 19, wherein the plurality of different tools or sets of tools include a grab comprising at least two tines in one tool carrier and at least two tines in the other tool carrier, in which the said tines in one tool carrier are connected by a web, and are so located and spaced that they pass just between the said two tines in the other tool carrier.

21. A multipurpose attachment according to claim 20' wherein the two tines on the said other tool carrier are themselves provided with outwardly extending webs or fins.

22. A multipurpose attachment according to any one of the preceding claims, wherein the or each tool carrier is fabricated from an assembly of structural plates having interengaging tongues and slots, whereby a skeleton framework is assembled prior to welding to effect a permanent mounting frame for the tools.

23. A multipurpose attachment according to claim 22 wherein the or each tool carrier includes an inner cross member in the form of a plate in tongue and slot engagement with respective side plates of the tool carrier.

24. A multipurpose attachment according to claim 22 or 23 wherein receiving channels or sockets for the tools on the tool carrier are provided within the tool carrier structure.

25. A multipurpose attachment according to any one of the preceding claims wherein the plurality of different tools or sets of tools include one or more of pallet tines, rakes and dozer blades.