WO1989003800A1

WO1989003800A1 - Crane-mounted implement

Info

Publication number: WO1989003800A1
Application number: PCT/SE1988/000467
Authority: WO
Inventors: Börje BAUMGARTEN
Original assignee: Hiab-Foco Ab
Priority date: 1987-10-19
Filing date: 1988-09-12
Publication date: 1989-05-05
Also published as: FI901929A0; AU2602888A

Abstract

A crane-mounted implement comprises two hydraulically operated claw-like halves (2, 3) hingedly connected with a supporting frame (1). Each claw half has a pair of spaced-apart but mutually connected flat side members (4, 5, 6, 7) whose planes are substantially parallel and of which one side member of one of said pairs can pass closely to and on the inside of a cooperating side member of said other pair. For pivotal movement of the claw halves between an open and a closed position, two hydraulic cylinders (12, 12') are provided, each of which is positioned substantially in the same plane as two cooperating and juxtaposedly movable side members (4, 6; 5, 7) on both claw halves and has its cylinder element (13) hingedly connected with one side member and its piston rod hingedly connected with the other side member.

Description

CRANE-MOUNTED IMPLEMENT

Field of the invention

In a first aspect, the present invention relates to a crane-mounted implement, in particular a grapple, comprising two hydraulically operated claw-like halves hingedly connected with a supporting frame for pivotal . movement between an open position and a closed position by means of two double-acting hydraulic cylinders, each of said halves having a pair of spaced-apart but mutually connected flat side members whose planes are substantially parallel and of which one side member of one of said pairs can pass closely to and on the inside of a co¬ operating side member of said other pair, a device, for example a rotator, being connected or connectible with said frame for suspending the implement from the tip of a crane.

Background of the invention

Implements of the above-mentioned type are used as timber grapples on both road and off-road vehicles for loading and unloading tree stems, logs etc. Prior art timber grapples often have a single horizontally or vertically operating hydraulic cylinder centrally mounted on the frame for pivoting the claw halves between the open and closed positions. To impart adequate gripping power to the claw halves, not only the hydraulic cylinder proper, but also the construction details which serve to distribute the forces supplied by the centrally posi¬ tioned hydraulic cylinder to each of the four claw side members cooperating in pairs (and farthest away from the cylinder) must be very strongly dimensioned. As a result, the entire implement will be comparatively heavy, and in actual service an excessive dead weight of the implement obviously is a disadvantage. Thus, the carrying capacity of a given crane structure is reduced in direct proportion to an increase in dead weight, and also the carrying capacity of the vehicle is reduced. Furthermore, the construction of a heavy and unwieldy implement requires a great deal of material, which increases the production costs. A further dis- advantage of prior art timber grapples is their great overall height which is due to the fact that the hydraulic cylinder is always accommodated in a space underneath the rotator or suspension device in which the implement is mounted at the crane tip. The great overall height implies that the implement must be raised far above and away from the crane-mounting to allow it to go free of for example the stakes of a logging truck. It is precisely this leverage which determines the maximum permissible load of the grapple, and the higher the implement must be raised above the crane-mounting or the farther it must be extended therefrom, the lower the maximum permissible load will be. Finally, it should be mentioned that the replacement of worn or damaged claw halves and other repairs on prior art grapples is expensive, primarily because the hydraulic cylinder must first be dismantled. Brief description of the inventive concept

The present invention aims at obviating the above- mentioned disadvantages of prior art grappling implements and providing a compact implement of low dead weight. According to the primary characteristic features of the invention, these and other objects are achieved in that the individual hydraulic cylinder is positioned substantially in the same plane as two cooperating and juxtaposedly movable side members on both claw halves and has its cylinder element hingedly connected with one side member and its piston rod hingedly connected with the other side member. Further illustration of prior art Derwent's abstract G 2472D/27 Sϋ 770,996 discloses a timber grapple having two hydraulic cylinders which, however, are not mounted in the same plane as the side members of the claw halves, and this means that the hydraulic cylinders will take up a large part of the space at the centre of the grapple so that the rotator must be connected with the grapple at a point above the hydraulic cylinders. Furthermore, the hydraulic cylinders must be connected with each claw half via protruding pins which make the construction highly vul¬ nerable. Besides, this grapple has the same disadvantages as a conventional one-cylinder grapple because each individual hydraulic cylinder operates but one claw half, which means that the construction elements serving to transfer the power from the hydraulic cylinder must be exceedingly sturdy and heavy. A similar grapple suf¬ fering from the same disadvantages is disclosed in FR patent specification 2,190,709.

In a further aspect, the present invention relates to a crane-mounted implement, in particular a grapple, comprising two claw-like halves hingedly connected with a supporting frame for pivotal movement between an open position and a closed position by means of two double- acting hydraulic cylinders, each of said halves having a pair of spaced-apart but mutually connected side mem¬ bers, a device, for example a rotator, being connected or connectible with said frame for suspending the i ple- ment from the tip of a crane.

An obvious disadvantage of the timber grapple accord¬ ing to SU 770,996 (as also in conventional grapples having but one hydraulic cylinder) is its great overall height which is due to the fact that the hydraulic cyl- inders have been built into a space underneath the rotator or suspension device from which the implement is suspended. from the crane tip, more particularly underneath a high- level cross member on which the suspension device is mounted. The great overall height implies that the i ple- ment must be raised far above and away from the crane- mounting to allow it to go free of for example the stakes of a logging truck. It is precisely this leverage which determines the maximum permissible load of the grapple, and the higher the implement must be raised above the crane-mounting or the farther it must be extended there¬ from, the lower the maximum permissible load will be. In its second aspect, the present invention aims at obviating the above-mentioned disadvantages of prior art grappling implements and providing a compact implement of low dead weight. These and other objects are achieved, according to the invention, in that the two hydraulic cylinders are mounted on a frame member, such as a hollow section, on the upper side of which the suspension device or rotator is mounted, more particularly between the hydraulic cylinders, thereby reducing the overall height of the implement to a minimum. In a third aspect, the invention relates to a crane- mounted implement, in particular a grapple, comprising two claw-like halves hingedly connected with a supporting frame for pivotal movement between an open position and a closed position, each of said halves having a pair of spaced-apart but mutually connected flat side members whose planes are substantially parallel and of which one side member of one of said pairs can pass closely to and on the inside of a cooperating side member of said other pair, a device, for example a rotator, being connected or connεctible with said frame for sus¬ pending the implement from the tip of a crane.

On prior art implements of this type, the side members of the claw halves are symmetrically positioned on the frame, for which reason the two claw halves must be made unequal in size so that one half can engage with the other. This makes the process of manufacture impractical and expensive.

In its third aspect, the invention aims at obviat¬ ing the above-mentioned disadvantage of prior art grap- pling implements and providing an implement which can be manufactured expediently and at low cost. This is achieved, according to the invention, in that two joints forming a geometrical axis about which one claw half is pivotal, are positioned at a different level, relative to the frame, than the joints about which the other claw half is pivotal, whereby all four side members can be manufactured in identical designs. Brief description of the drawings

In the drawings Fig. 1 is a perspective view of the implement according to the invention, the two claw halves being shown in an intermediate position between the maximally open and the maximally closed position; Fig. 2 is a top plan view of the implement shown in

Fig. 1; Fig. 3 is a lateral view of the implement; and Fig. 4 is an end view of the implement.

Detailed description of a preferred embodiment of the invention

In Fig. 1, a frame generally designated 1 carries two privotal claw halves 2, 3 each comprising a pair of spaced-apart but mutually connected side members

4, 5 and 6, 7, respectively, in the form of curved tapered plates. The two side members of each such pair are rigidly interconnected via on the one hand a stiffening tube 8 located in the area between the side member end portions and, on the other hand, a plate member 9 at the free end portions of said side members.

The frame 1 comprises a lower cross member 10 and two box-shaped structures 11, 11' perpendicular to said cross member and lying in substantially the same plane as the side members 4, 6 and 5, 7, respectively, of the two claw halves 2 and 3. Each box structure includes a piston and cylinder assembly or hydraulic cylinder 12, 12' of conventional double-acting type. Each such hydraulic cylinder thus includes a cylinder element 13 and a piston rod 14. Since the two box structures 11, ll¹ are identical, although mirror inverted, only one of these structures will be described below, reference being had also to Figs 2-4.

The individual box structure 11 includes two spaced- apart and substantially parallel elongate plates or plate-like members 15, 16 which, in the area of their lower edges, are located on the transverse box section 10, for example by means of bolted connections to permit dismantling of said plate members. As is best seen from Fig. 1, each outer plate member 16 has its inner side engaging with an end of the box section 10 and is screwed thereto, while the inner plate member 15 has an angled lower flange engaging with the upper side of the hollow section and screwed thereto. At the opposite ends of the elongate plate members 15, 16, pivot pins 17, 17* and 18, 18*, respectively, are arranged in pairs to form joints which are termed principal joints 17, 18 hereinafter, one for each U-shaped end member 19, 20 of the cooperating side members 6 , 4 of the two claw halves. Each such end member 19, 20 is in the form of a section which is U-shaped in cross-section and comprises two parallel side flanges 21, 21' and a bottom 22 to the outer side of which a planar plate 23 is welded which in turn is connected with the associated side member via a bolted connection comprising a suitable number of bolts 24 and nuts. Each such bolt unit prefer— ably has a bushing which is inserted in pre-bored holes both in the plate 23 and in the associated side member and which serves to take up any shear forces between these members. Extending between the side flanges 21, 21' of the U member 19 is a pivot pin 25 with which the free end of the piston rod 14 is pivotally connected. The U member 20 has, in analogous manner, a pivot pin 26 with which the rear end of the cylinder element 13 is pivotally connected. As is best seen from Fig. 3, the pivot pins 25, 26 lie in the area of the upper ends of U members 19, 20 and on a level above the principal joints 17, 18. Mounted between the pivot pin 26 of the U member 20 and a further joint 27 in the area of the lower edge of said U member 19 is a diagonal strut 28 which, in per se known manner, ensures that the two claw halves 2, 3 will move uniformly inwardly and out¬ wardly relative to the centre of the implement during operation of the piston and cylinder assemblies 12, 12'.

It appears from Fig. 2 that the stiffening tube 8 and the plate member 9 interconnecting the side members 6 and 7 is slightly longer than the tube 8' and the plate member 9¹ interconnecting the side members 4,

5 of the other claw half. In this manner, the claw half can be accommodated within the side members 6, 7 of the claw half 3 when the claw halves are swung into closed position. Furthermore, it appears from Fig. 3 that the principal joints 18 of the claw half 2 lie on a slightly higher level than the principal joints 17 of the claw half 3 relative to the box structures 11, 11'. In Fig. 3, this difference of level is designated 29. By thus placing the joints 17, 18 at different levels relative to the frame, one gains the advantage that all four side members 4, 5, 6, 7 can be manufactured in large series in one and the same form and with the same dimensions and yet permit the narrower claw half 2 to swing into the slightly wider claw half 3. It should here be noted that the claw half 3 is but slightly wider than the claw half 2, which means that the side members 4, 5 will pass closely to and on the inside of the corre¬ sponding side members 6, 7 of the claw half 3 when the two halves are brought together. Fig. 1 shows that the inner plate members 15 of the box structures 11, 11' have elongate holes 30. Through these holes, the hydraulic hoses (not shown) from the two hydraulic cylinders 12, 12' are passed.

Fig. 4 shows a rotator 31 which, in accordance with the invention, is mounted on the transverse hollow sec¬ tion 10 of the frame. The walls of the hollow section may be formed with holes 32 within which the conventional and commercially available rotator 31 can be fixed by bolted connections. Since the hollow section 10 lies on a lower level than the surrounding hollow structures 11, 11* and the hydraulic cylinders 12, 12' therein, the overall height of the implement will be minimal.

The grapple as disclosed herein operates as follows. Upon inward movement of the pistons in the hydraulic cylinders 12, 12', the U-shaped end members 19, 20 of the respective cylinder will pivot about the associated pincipal joints 17, 18 while carrying the claw halves 2, 3 along, such that these are swung in an outward direction into open position. Upon outward movement of the pistons in the hydraulic cylinders, the claw halves will be swung in an inward direction into closed position. In their inner end positions as shown by the broken lines in Fig..3, the claw halves 2, 3 will define, together with the underside of the frame, a very small space 33, and this means that the grapple is capable of handling also very small objects, for example a single and slender young tree.

A particular advantage of the grapple according to the invention is that each of the two hydraulic cyl¬ inders operates in the same plane as the side members of the claw halves, which means that the power can be transmitted directly between the hydraulic cylinders and the said side members, and this in turn means that the entire construction can be relieved of the heavy type of power transmission means required on conventional grapples having but one cylinder. Furthermore, since. the power is transmitted in the same plane as the side members of the claw halves, both hydraulic cylinders can be relatively small and ^'yet give adequate gripping power. A further advantage of the g-rapple according to the invention is the low overall height which has been mentioned above and which, in actual service, gives an increased carrying capacity to which must be added the increased carrying capacity that has already been obtained by the lower dead weight of the grapple. In addition, maintenance of the grapple is greatly facili¬ tated because the bolted connections 24 allow the two claw halves to be readily dismantled from the rest of the implement. Finally, it should be mentioned that the production costs of the grapple according to the invention are reduced considerably as compared with conventional grapples, not only because less material is required, but also because the side members of the claw halves can be given one and the same standard design. It is obvious that the invention is not restricted to the embodiment described above and illustrated in the drawings. Thus, the inventive concept is applicable also to other crane-mounted implements than timber grap- pies. For example, the implement may be a bucket, in which case one simply has to enlarge the side members of the claw halves and to mount a couple of plates ex¬ tending from the lower free ends of the side members to the area of the upper ends thereof, possibly while dispensing with the stiffening tubes illustrated.

Claims

1. Crane-mounted implement, in particular a grapple, comprising two hydraulically operated claw-like halves

(2, 3) hingedly connected with a supporting frame (1) for pivotal movement between an open position and a closed position by means of two double-acting hydraulic cylinders (12, 12'), each of said halves having a pair of spaced-apart but mutually connected flat side members (4, 5; 6, 7) whose planes are substantially parallel and of which one side member of one of said pairs can pass closely to and on the inside of a cooperating side member of said other pair, a device (31), for example a rotator, being connected or connectible with said frame for suspending the implement from the tip of a crane, c h a r a c t e r i s e d in that the individual hydraulic cylinder (12, 12*) is positioned substantially in the same plane as two cooperating and juxtaposedly movable side members (4, 6; 5, 7) on both claw halves and has its cylinder element (13) hingedly connected with one side member (4, 5) and its piston rod (14) hingedly connected with the other side member (6, 7).

2. Implement as claimed in claim 1, c h a r a c ¬ t e r i s e d in that the individual hydraulic cylinder (12, 12") is located in the space between two elongate, mutually spaced-apart plates or plate-like members (15, 16) of the frame (1), the opposite ends of said members being provided with principal joints (17-, 18) carrying U-shaped end members (19, 20) of each of the two co¬ operating side members (4, 6; 5, 7) of the respective claw halves (2, 3), and that both the cylinder element (13) and the piston rod (14) are connected with the associated U-shaped end member via a pivot pin (25, 26) extending between two parallel flanges (21, 21') of said end member and located above the principal joint (17, 18) of the same end member.

3. Implement as claimed in claim 2, c h a r a c ¬ t e r i s e d in that two pairs (11, 11') of plate members (15, 16) constitute the frame (1) together with a transverse member (10), such as a hollow section which is mounted at the lower side of said plate members (15, 16) and on the upper side of which the suspension device or rotator (31) is mounted, thus reducing the overall height of the implement to a minimum.

4. Implement as claimed in claim 2 or 3, c h a r a c t e r i s e d in that the side members (4, 5, 6, 7) of said claw halves (2, 3) are connected with associated U-shaped end members (19, 20) via bolted connections (24) permitting dismantling and remounting of said claw halves without necessitating dismantling of the hydraulic cylinders (12, 12') from the frame.

5. Implement as claimed in any one of claims 2-4, c h a r a c t e r i s e d in that the two principal joints (17) forming a geometrical axis about which one claw half (3) is pivotal, are located on a different level* relative to the frame or plate members (15, 16) than the principal joints (18) about which the other claw half (2) is pivotal.

6. Implement as claimed in any one of claims 2-6, c h a r a c t e r i s e d in that a diagonal strut (28) is hingedly connected with the upper part of one U-shaped end member (20) and with the lower part of the other U-shaped end member (9) to ensure uniform pivotal movement of the claw halves during operation of the hydraulic cylinders. 7. Implement as claimed in any one of the preceding claims, c h a r a c t e r i s e d in that the two side members (4, 5; 6,

7) of each claw half (2, 3) are rigidly interconnected by means of a stiffening tube (8, 8') located in the area between the end portions of the side members and by means of a plate member (9, 9¹) at the free end. portions of said side members.

8. Crane-mounted implement, in particular a grapple, comprising two claw-like halves (2, 3) hingedly connected with a supporting frame (1) for pivotal movement between an open position and a closed position by means of two double-acting hydraulic cylinders (12, 12'), each of 5 said halves having a pair of spaced-apart but mutually connected side members (4, 5; 6, 7), a device (31), for example a rotator,, being connected or connectible with said frame for suspending the implement from the tip of a crane, c h a r a c t e r i s e d in that i the two hydraulic cylinders (12, 12') are mounted on a frame member (10), such as a hollow section, on the upper side of which the suspension device or rotator (31) is mounted, more particularly between the hydraulic cylinders, thereby reducing the overall height of the

15 implement to a minimum.

9. Implement as claimed in claim 8, c h a r a c ¬ t e r i s e d in that the two side members (4, 5; 6, 7) of each pair of side members are flat and have their planes substantially in parallel, one side member of

20 one pair being able to pass closely to and on the inside of a cooperating side member of the other pair, and that the individual hydraulic cylinder (12, 12') is located substantially in the same plane as two cooperating and juxtaposedly movable side members (4, 6; 5, 7) of

25 the two claw halves and has its cylinder element (13) hingedly connected with one side member (4, 5) and it^'s piston rod (14) hingedly connected with the other side member (6, 7) .

10. Implement as claimed in claim 9, c h a r a c -

30 t e r i s e d in that the individual hydraulic cylinder (12, 12') is located in the space between two elongate, mutually spaced-apart plates or piate-1ike_^members (15, 16) of the frame (1), the opposite ends of said members being provided with principal joints (17, 18) carrying

35 u-shaped end members (19, 20) of each of the two co¬ operating side members (4, 6; 5, 7) of the respective claw halves (2, 3), and that both the cylinder element (13) and the piston rod (14) are connected with the associated U-shaped end member via a pivot pin (25, 26) extending between two parallel flanges (21, 21') of said end member and located above the principal joint (17, 18) of the same end member.

11. Implement as claimed in claim 10, c h a r a c ¬ t e r i s e d in that the side members (4, 5, 6, 7) of said claw halves (2, 3) are connected with associated U-shaped end members (19, 20) via bolted connections (24) permitting dismantling and remounting of said claw halves without necessitating dismantling of the hydraulic cylinders (12, 12') from the frame.

12. Implement as claimed in claim 10 or 11, c h a r a c t e r i s e d in that the two principal joints (17) forming a geometrical axis about which one claw half (3) is pivotal, are located on a different level relative to the frame or plate members (15, 16) than the principal joints (18) about which the other claw half (2) is pivotal.

13. Implement as claimed in any one of claims 10-12, c h a r a c t e r i s e d in that a diagonal strut (28) is hingedly connected with the upper part of one U-shaped end member (20) and with the lower part of the other U-shaped end member (9) to ensure uniform pivotal movement of the claw halves during operation of the hydraulic cylinders.

14. Implement as claimed in any one of claims 8-13, c h a r a c t e r i s e d in that the two side members (4, 5; 6, 7) of each claw half (2, 3) are rigidly inter- connected by means of a stiffening tube (8, 8') located in the area between the end portions of the side members and by means of a plate member (9, 9') at the free end portions of said side members.

15. Crane-mounted implement, in particular a grapple, comprising two claw-like halves (2, 3) hingedly connected with a supporting frame (1) for pivotal movement between an open position and a closed position, each of said halves having a pair of spaced-apart but mutually con¬ nected side members (4, 5; 6, 7) whose planes are sub¬ stantially parallel and of which one side member of one of said pairs can pass closely to and on the inside of a cooperating side member of said other pair, a device (31), for example a rotator, being connected or connect- ible with said frame for suspending the implement from the tip of a crane, c h a r a c t e r i s e d in that two joints (17) forming a geometrical axis about which one claw half (3) is pivotal, are positioned at a dif¬ ferent level relative to the frame (1) than the joints (18) about which the other claw half (2) is pivotal, whereby all four side members (4, 5, 6, 7) can be manu¬ factured in identical designs.

16. Implement as claimed in claim 15, c h a r a c ¬ t e r i s e d in that said claw halves (2, 3) are pivotal by means of two hydraulic cylinders (12, 12') of the double-acting type, the individual hydraulic cylinder (12, 12') being located substantially in the same plane as two cooperating and juxtaposedly movable side members (4, 6; 5, 7) on both claw halves and has its cylinder element (13) hingedly connected with one side member (4, 5) and its piston rod (14) hingediy connected with the other side member (6, 7).

17. Implement as claimed in claim 16, c h a r a c ¬ t e r i s e d in that the individual hydraulic cylinder (12, 12') is located in the space between two elongate, mutually spaced-apart plates or plate-like members (15, 16) of the frame (1), the opposite ends of said members being provided with principal joints (17, 18) carrying U-shaped end members (19, 20) of each of the two co¬ operating side members (4, 6; 5, 7) of the,respective claw halves (2, 3), and that both the cylinder element (13) and the piston rod (14) are connected with the associated U-shaped end member via a pivot pin (25, 26) extending between two parallel flanges (21,. 21') of said end member and located above the principal joint (17, 18) of the same end member.

18. Implement as claimed in claim 17, c h a r ¬ a c t e r i s e d in that two pairs (11, 11') of plate members (15, 16) constitute the frame (1) together with a transverse member (10), such as a hollow section which is mounted at the lower side of said plate members (15, 16) and on the upper side of which the suspension device or rotator (31) is mounted, thus reducing the overall height of the implement to a minimum.

19. Implement as claimed in claims 16 and 17, c h a r a c t e r i s e d in that the side members (4, 5, 6, 7) of said claw halves (2, 3) are connected with associated U-shaped end members (19, 20) via bolted connections (24) permitting dismantling and remounting of said claw halves without necessitating dismantling of the hydraulic cylinders (12, 12') from the frame.

20. Implement as claimed in any one of claims 17-19, c h a r a c t e r i s e d in that a diagonal strut (28) is hingedly connected with the upper part of one U-shaped end member (20) and with the lower part of the other U-shaped end member (19) to ensure uniform pivotal movement of the claw halves during operation of the hydraulic cylinders.

21. Implement as claimed in any one of claims 15-20, c h a r a c t e r i s e d in that the two side members

(4, 5; 6, 7) of each claw half (2, 3) are rigidly inter¬ connected by means of a stiffening tube (8, 8') located in the area between the end portions of the side members and by means of a plate member (9, 9') at the free end portions of said side members.