WO1989002957A1

WO1989002957A1 - Pivotable tool attachment for mounting on excavators

Info

Publication number: WO1989002957A1
Application number: PCT/SE1988/000479
Authority: WO
Inventors: Jan Rehnman
Original assignee: Jan Rehnman
Priority date: 1987-09-18
Filing date: 1988-09-14
Publication date: 1989-04-06
Also published as: SE8703622L; AU2524988A; SE459018B; SE8703622D0

Abstract

The present invention relates to a pivotable tool attachment for mounting on excavators, tractor diggers and the like, comprising an attachment part (1) designed to be hooked onto the stick of an excavating unit by means of a quick coupling mounted thereon, and a tool holder (2), onto which a pipe-laying boom (3), for instance, can be mounted. The attachment part consists of two plates (4, 8) pivotably connected together, which can be turned in relation to each other by the tool holder (2) being pressed against a support, and which are locked to each other by the tool attachment being lifted from the ground.

Description

Pivotable tool attachment for mounting on excavators The present invention relates to a pivotable tool attachment for mounting on excavators, tractor diggers and the like.

Today's methods of pipe-laying include the use of lifting straps suspended in suitable manner from the stick, i.e. the front part of the machine arm, or a tool mounted thereon. However, such methods do not allow manipulation of the pipe by the operator. Instead this must be done by personnel working outside the machine. Furthermore, the pipes must be positioned by separte means, also by personnel working outside the machine. Pipe-lay¬ ing today reguires a large number of workers and can also be dangerous for those working below the suspended load. Further¬ more, equipment for pulling the pipes together is required, as well as lifting means.

Pivotable tool attachments exist today but in ail known cases they are permanenttly mounted on special machines and can thus only be used for one single purpose, e.g. edge-cutting along highways. The attachment is in this case operated by means of hydraulic cylinders. This equipment is extremely expensive and its having to be permanently mounted on a machine means that smaller businesses are unable to afford such equipment.

The object of the present invention is to provide a pivotable tool attachment, where the above-mentioned drawbacks and limitations are eliminated, which can easily be mounted on an excavator stick or the like, and which can be manipulated from the operator's cab, which permits both laying and positioning cf the pipes in a trench, is simple and reliable and on which any tool can be mounted.

This is achieved with the tool attachment according tc the present invention which is characterised by two elements con¬ nected pivotably to each other, one element being designed for mounting on a quick coupling for an axcavatcr stick and the other being provided with a tccl holder, said elements being arranged to be automatically locked together by the weight of the tool holder or a tool arranged thereon, and to be auto¬ matically released from each other when said load is removed.

According to a preferred embodiment of the invention said elements comprise an attachment plate, one surface of which is intended to be mounted on said quick coupling, and on the other surface of which are arranged a pivot and a pivot plate provided with a central hole through which said pivot passes, and on the surface of which facing away from the attachment plate is arranged a tool holder, a bearing being arranged on the pivot and recessed in the central hole of the pivot plate, and also locking means for locking the pivot plate on the pivot.

According to another embodiment of the invention the pivot plate is tiitable in relation to the attachment plate, the tool holder is arranged on the pivot plate with its centre of gravity dis¬ placed in relation to the central hole, and friction linings are arranged on the surfaces of the plates facing each other.

According to yet another embodiment of the invention a circular, ringshaped friction lining is arranged on the attachment plate and adjustable friction pads are arranged on the pivot plate, spaced around the circumference of a circle corresponding to the friction lining on the attachment plate. The arrangement of adjustable friction pads on the side of the pivot plate where the tool holder is arranged, allows these pads to absorb any lateral forces exerted on the arrangement. An extremely simple, robust and reliable arrangement is thus obtained with a minimum of movable parts. Furthermore, the pivot resistance in unloaded state can also be adjusted and the tool is thereby prevented from swinging uncontrollably when being moved, for instance.

According to a further embodiment of the invention the attachment plate is provided with a peripheral protruding edge, concentrically surrounding the pivot, and the pivot plate is circular and is provided with contact means arranged to abut against said protruding edge when the attachment plate and pivot plate are substantially parallel, i.e. when the tool holder or tool is unloaded.

According to a further embodiment of the invention the plates are arranged to be locked together by means of a locking pin arranged to pass through a hole in the pivot plate, said locking pin extending in locking position into one of a number of holes or recesses evenly spaced in a circle in the attachment plate, and being arranged to automatically lock or release the plates.

According to a further embodiment of the invention the locking pin is arranged to be operated by a link arranged in the tool holder and protruding at its end located opposite the pivot plate, to be influenced by a tool secured in the holder.

According to a further embodiment of the invention the attach¬ ment plate is provided with a peripheral protruding edge, con^¬ centrically surrounding the pivot, the pivot plate being circu¬ lar and being provided with contact means which, in combination with a bearing on the pivot, are arranged to guide the pivot plate towards the attachment plate.

According to a further embodiment of the invention the tool holder comprises a preferably tubular, elongate element mounted on the pivot plate close to an edge, and at least one preferably tubular support element arranged between the holder and an opposing edge portion of the pivot plate.

According to a further embodiment of the invention, in which the tool attachment is inteded for pipe-laying, the tool holder is provided with attachment lugs allowing pivotable attachment of a boom which, during pipe-laying, is inserted into a pipe and can be withdrawn from a pipe which has been laid ty turning the tool attachment at an angle. The owable boom will thus be turned tc form an acute angle with the attachment, thus enabling the bcoir. to be withdrawn from a pipe which has been laid even in extremely narrow service ducts. According to a further embodiment of the invention the friction linings on the plates consist of clutch linings of the type used in hydraulically controlled construction machinery, which pro^¬ vide extremely efficient locking and long service life.

Additional objects, advantages and features of the invention will be revealed in the following detailed description of the functioning of the arrangement with reference to the accom¬ panying drawings, in which

Figure 1 shows one embodiment of the tool attachment according to the present invention,

Figure 2 shows a second embodiment of the tool attachment according to the present invention,

Figure 3 shows a third embodiment of the tool attachment accor¬ ding to the invention,

Figure 4 shows a schematic view of a part of the tool attachment according to Figure 3, and

Figure 5 shows a cross section through the part illustrated in Figure 4.

Figure 1 shows one embodiment of the tool attachment according to the invention, designed as a pipe "trunk". The tool attach¬ ment consists of a pivotable attachment part 1 and a tool hoice; 2. A boom or "trunk" 3 is mounted on the tool holder 2.

The pivotable attachment part 1 consists of an attachment plate 4, on the upper side of which an optinal quick coupling may be mounted by means of welding, for instance. A pivot 5 is arranged in the attachment plate and is provided with screw threads for a locking nut 6. A bearing 7 is provided on the pivot, preferably an axial swing bearing. On the bearing 7 is a pivot plate 8 having a central hole 9. Friction linings 10, 11 are arranged on the facing surfaces of the attachment plate and the pivot plate. The lining 10 on the attachment plate 4 is preferably circular, ring-shaped and surrounds the pivot 5 concentrically, whereas the friction lining 11 on the pivot plate 8 is not in the form of a coherent unit. The linings preferably consist of clutch linings of the type used in hydraulically controlled construction machines and the like.

A tool holder 2, preferably in the form of a tubular boom or beam 12 and at least one preferably tubular support element 13, is mounted on the pivot plate 8 in such a way that its centre of gravity is displaced towards the edge of the pivot piate. The friction-generating element 11 on the pivot plate 8, if in the form of a segment of a circle-ring, or at least with less extension than the corresponding element on the attachment plate, is arranged at the edge of the pivot plate opposite to the centre of gravity of the tool holder.

In the embodiment shown in the tool attachment according to the invention, a protruding edge 14 is arranged concentrically around the pivot 5 on the attachment plate 4. The pivot plate 6, in this case circular, is arranged with its downwardly facing surface 15 substantially on a level with the downwardly facing limiting surface 16 of the edge 14.

The pivot plate 8 is also provided with at least one contact element, a roller bearing 17 in the embodiment shown, which is arranged on an attachment 18 mounted on the pivot plate. Extre¬ mely important to the invention is that when the attachment pla¬ te and pivot plate assume positions substantially parallel to each other there is a clearance between them. The roller bea- ring(s) 17 can then _abut the edge 14 and the pivot plate 8 can be turned freely and optionally in relation to the attachment plate 4. The tool attachment described above functions as follows: With the aid of a quick coupling, not shown, mounted on the attach¬ ment plate 4, the machine operator can easily hook on the tool attachment without leaving his cab. The attachment plate and pivot plate are caused to assume positions parallel to each other by pressing the end 12 of the tool holder against the ground or some other support. The pivot plate can then be freely turned in relation to the attachment plate by operating the stick from inside the operator's cab, without the operator having to get out and without the need for any other aids. When the tool attachment is lifted, the friction lining 11 on the pivot plate will be pressed against the friction lining 10 on the attachment plate, thanks to the shift in the centre of gravity of the tool holder on the pivot plate 8 mentioned above, and the attachment will therefor be locked in the desired position. When a tool on the attachment is loaded, this locking effect is further reinforced as the load increases.In the embodiment shown the contact elements 17 prevent the pivot plate from being pressed up against the attachment plate on the side supporting the holder 12 during the turning adjustment. In a simplified embodiment the edge 14 and contact elements 17 may be omitted, however, but the friction lining 11 on the pivot plate should in that case consist of a segment which does net extend so far on the pivot plate that it could come into contact with the friction lining on the attachment plate as this would hinder or event prevent the turning movement.

The tool holder 12 can be provided with any type of attachment means for attaching different tools. Attachment lugs 19 are provided in the embodiment shown, in which lugs the boom 3 can be swung up towards the holder 12, as indicated by the broken lines in Figure 1. However, some form of safety arrangement is preferably provided to prevent the boom from falling unintentionally from an upright position. Alternatively, a step may be arranged to prevent the boom from being raised more than about 45°, in which case it is prevented from remaining in raised position. The big advantage of having a swinging boom is that, by inclining the tool attachment, the boom can then be withdrawn from pipes laid in narrow service shafts.

Other tools which can be fitted on this version of the tool holder are e.g. lifting forks, clamping means for lifting wells, etc.

In the embodiment of the invention shown in Figure 1, it may be considered that there is an insufficient safety margin in the locking effect between the plates when handling light loads in special applications. This is avoided in the embodiment shown in Figure 2.

In the alternative embodiment shown in Figure 2, in which the plates are locked mechanically to each other, the tool attach^¬ ment is still operated in the same way as in the embodiment des¬ cribed above. Holes or recesses 22 are arranged in the attach¬ ment plate, here designated 21, and are spaced uniformly around the periphery of a circle. Contact means 24 are arranged on the pivot plate, designated 23, which keep the plates parallel to each other and facilitate pivoting of the plates in relation to each ether. A through-hole 25 is also arranged in the pivct plate 23, through which a locking pin 26 passes. The front part of the pin shall preferably be shaped so that it is guided into the holes in the attachment plate, e.g. by bevelling the tip to suit the division between said holes or recesses, eliminating any risk of the locking pin being pressed against the attachment plate without producing a locking engagement. The locking pin 26 preferably runs in a sleeve 28 arranged in the tubular tool holder 27, and a compression spring 29 is preferably also ar^¬ ranged between the sleeve 28 and a shoulder 30 on the locking pin or an extension thereon. The locking pin 26 is arranged by means of a link 31 to extend through the holder to its lower end, it being in the form of a rod, for instance, the lower end of which lies edge to edge with the lower end surface cf the holder in locked position. This arrangement allows the locking effect between the plates to be disengaged by pressing the boom 32 against a support so that its rear end 33 swings down from the holder and locking pin due to its own weight and is released from the locking position, possibly by means of spring action.

Figure 3 shows another alternative embodiment of the tool attachment according to the invention which, however, functions in pricipally the same manner as the preceeding embodiments. A circular, ring-shaped friction lining 37 is secured to the attachment plate 35 by means of screws 36. The pivot connection is the same as in Figures 1 and 2 and is therefore not further discussed here. A plurality of adjustable friction pads 39 are arranged on the pivot plate 38.

Figure 4 illustrates a suitable arrangement of the friction pads on the pivot plate, three friction pads 39 a, b and c being arranged at the side opposite the attachment of the tool holder and two friction pads 39 d and e at the side of the pivot plate carrying the tool holder.

An example of the adjustable friction pads is shown in cross section in Figure 5, where the pads 39 are adjustable in the surface plane of the pivot plate facing the attachment plate. The device enabling this comprises an internally threaded sleeve 40 secured in the pivot plate. A screw 41 to which the friction pad is attached by glueing, for instance, runs in the sleeve 40, allowing vertical adjustment of the friction pad with respect tc the surface plane of the pivot plate.

This latter embodiment offers several advantages. Arranging the friction pads adjustably on one of the plates enables the turning resistance to be set even for unloaded tools. This prevents pipes being damaged, for instance, when the tool is withdrawn, which may easily happen with hydraulicaily controlled tools where the tool is held quite rigidly unless the operator observes the danger and manipulates the tool to go free from the pipe during withdrawal. At the same time the turning resistance can be set so that the tool does not swing freely in unloaded state. Furthermore, the described arrangement offers an extre^¬ mely simple and reliable absorption of turning momentum, thanks to the two adjustable friction pads 39 d, e arranged on each side of the attachment point of the tool holder.

Further development of the tool attachment is of course also feasible, or a combination of friction locking and mechanical locking without deviating from the invention as defined in the following claims.

Claims

C l a i m s

1. A pivotable tool attachment for mounting on excavators, tractor diggers and the like, c h a r a c t e r i s e d by two elements (4, 8; 21, 23; 35, 38) connected pivotably to each other, one element being designed for mounting on a quick coupling for an excavator stick and the other being provided with a tool holder (12; 27) , said elements being arranged to be automatically locked together by the weight of the tool holder or a tool arranged thereon, and to be automatically released from each other when said load is removed.

2. A tool attachment as claimed in claim 1, c h a r a c t e - r i s e d in that said elements comprise an attachment plate (4) , one surface of which is intended to be mounted en said quick coupling, and on the other surface of which are arranged a pivot (5) and a pivot plate (8) provided with a central hole (9) through which said pivot (5) passes, and on the surface of which facing away from the attachment plate (4) is arranged a tool holder (2) , a bearing (7) being arranged on the pivot (5) and recessed in the central hole (9) of the pivot plate (S) , and also locking means (6) for locking the pivot plate on the pivot.

3. A tool attachment as claimed in claim 2, c h a r a c t e - r i s e d in that the pivot plate (8) is tiltable in relation to the attachment plate (4) , that the tool holder (2) is arranged on the pivot plate (8) with its centre of gravity displaced in relation to the central hole (9) , and that friction linings (10, 11) are arranged on the surfaces of the plates facing each other.

4. A tool attachment as claimed in claim 3, c h a r a c t e - r i s e d in that the attachment plate (4) is provided with a peripheral protruding edge (14) concentrically surrounding the pivot (5) , that the pivot plate (8) is circular and is provided with contact means (17) arranged to abut against said protruding edge (14) when the attachment plate (4) and pivot plate (8) are substantially parallel, i.e. when the tool holder (2) or tool (3) is unloaded.

5. A tool attachment as claimed in claim 2, c h a r a c t e - r i s e d in that the plates (21, 23) are arranged to be locked togehter by means of a locking pin (26) arranged to pass through a hole (25) in the pivot plate (23) , said locking pin in locking position extending into one of a number of holes or recesses (22) evenly spaced in a circle in the attachment plate (21) , and being arranged to automatically lock or release the plates (21, 23) .

6. A tool attachment as claimed in claim 5, c h a r a c t e ¬ r i s e d in that the locking pin (26) is arranged to be operated by a link (31) arranged in the tool holder and protruding at its end located opposite the pivot piate, to be influenced by a tool (32) secured in the holder (27) .

7. A tool attachment as claimed in claims 5 or 6, c h a - r a c t e r i s e d in that the attachment plate (21) is provided with a peripheral protruding edge (34) concentrically surrounding the pivot, that the pivot plate (23) is circular and is provided with contact means (24) which, in combination with a bearing on the pivot, are arranged to guide the pivot plate (23) towards the attachment plate (21) .

8. A tool attachment as claimed in claim 3, c h a r a c t e - r i s e d in that a circular, ring-shaped friction lining (37) is arranged on the attachment plate (35) and that adjustable friction linings (3) are arranged on the pivot plate (38) , spaced around the circumference of a circle corresponding to the friction lining (37) on the attachment plate (35) .

9. A tool attachment as claimed in claim 1, c h a r a c t e - r i s e d in that the tool holder (2) comprises a preferably tubular, elongate element (12; 27) , mounted on the pivot plate (8; 23; 35) close to an edge, and at least one preferably tubular support element (13) arranged between the holder (12; 27) and an opposing edge portion of the pivot plate (8; 23; 35) .

10. A tool attachment as claimed in claim 1, intended primarily for pipe-laying, ch a r a c t e r i s e d in that it is provided with attachment lugs (19) allowing pivotable attachment of a boom (3; 32) which, during pipe-laying, is inserted into a pipe for lifting, laying and positioning, and which can be withdrawn from the pipe by turning the tool attachment at an angle.

11. A tool attachment as claimed inclaims 6 and 10, c h a - r a c t e r i s e d in that the boom (32) is provided with an extension (33) facing the holder (27) , said extension influen- cing the link (31) in the holder, which in turn influences the spring-loaded locking pin (26) .