DE29505222U1 - Clamshell buckets - Google Patents

Description

Clamshell grab

The invention relates to two-jaw grippers with the features of the preamble of claim 1.

Clamshell grabs of the generic design are constructed in such a way that the two shells are combined with a shell carrier, which is arranged at the lower end of a vertical support tube. The upper end of this tube is held by a rotator, which is attached to the excavator boom arm; at the lower end, the two support arms are attached to hold the two grapple shells, which can be operated with the help of hydraulic cylinders that pivot the support arms and thus the grapple shells to open and close. The shell carrier and grapple shells form a unit, so that when changing the grapple shells (e.g. for repair purposes or when exchanging a shell of a given shell width for a shell of a different shell width), the shell carrier must also be replaced. This represents a considerable effort, as the operator must therefore undertake very costly storage if he wants to have several different sizes or widths of shell grapples in stock and use them. This applies analogously to clamshell grabs that have a hydraulic cylinder arranged in the shell carrier tube.

Another embodiment of two-shell grabs (DE 34 25 036 C2) has a bow-shaped shell carrier, on the legs of which the shells are mounted around two axes that are parallel to one another and spaced apart from one another via their crossbeams that are welded to the shell side walls in the inner area of their upper edges. The crossbeams have actuating levers, at the ends of which a transverse hydraulic piston-cylinder unit connecting them is hinged. In order to enable the shells to be easily mounted with increased torsional rigidity, the crossbeams designed as shafts are provided with ring-shaped bearing surfaces on both sides of the longitudinal center line of the two-shell grab, which are mounted in split bearings. The legs of the shell carrier are provided on both sides with the inner bearing shells of the split bearings, onto which the outer bearing shells are screwed. This is intended to ensure high torsional stiffness.

rigidity of the shells while at the same time making storage of these shells easier.

The object of the invention is to design a clamshell grab of this type in such a way that, when changing from a set of shells of a certain size or width to a set of shells of a different size or width, it is possible in a particularly simple and cost-effective manner to only replace the shells themselves, and to carry out this replacement in a particularly simple, cost-effective and quick manner.

This object is achieved according to the invention with the features of the characterizing part of claim 1. Further embodiments of the invention are the subject of the subclaims.

The inventive proposal ensures that the separation point for changing the gripper shells is provided at the interface between the shell carrier and the gripper shells. This makes it possible to only replace the gripper shells themselves when changing gripper shells of one shell size compared to a different shell size, while the shell carrier with the support arms is not changed but can be used unchanged for all different dimensions of gripper shell sets. The use of shell grippers of different shell sizes can therefore be carried out with the present invention at minimal cost, since storage can be limited exclusively to the different gripper shell sets required.

Replacing gripper shells of different sizes is extremely simple. Since one and the same shell carrier with crossbars is used for all different shell sizes, the two-shell gripper is placed on the ground to change the shell, the connections between the crossbars and the gripper shells are released by removing the support bolts or similar (e.g. two bolts in total per side surface of the two-shell gripper), the shell carrier with the crossbars

and the crossbeam mounts are placed on another set of shells of the desired size, the holes in the bushings of the crossbeams are aligned with the holes in the crossbeam mounts, and the bolts are inserted into the holes and secured so that operation can then begin. In order to be able to insert the recesses of the gripper arms into the support bushings or similar of the gripper shells without any problems, the two gripper shells are kept closed for such a change, e.g. by a common lock, e.g. in the form of a plate; this lock is released and removed as soon as the gripper shells are connected to the shell carrier.

The invention is not limited to designs in which two hydraulic cylinders are coupled to the support arms outside the shell support tube. Rather, it also includes designs in which a hydraulic cylinder is arranged centrally within the shell support tube.

The invention is explained below in conjunction with the drawing using an exemplary embodiment. It shows:

Fig. 1 the shell carrier head with crossbeams, shell carrier tube and hydraulic cylinders separated from the gripper shells,

Fig. 2 shows the arrangement according to Fig. 1 in the operating state, and Fig. 3 is a side view of the arrangement according to Fig. 2.

One embodiment of a two-shell gripper 1 consists of gripper shells 2, 3, which in the case of Fig. 1 are shown closed with the open sides (cutting edges) 4, 5 of the two shells facing each other. To simplify the picking up of the gripper shells by the shell carrier, the two shells 2 and 3 are connected by locking plates 6, which are screwed to the side surfaces 2', 2", 3', 3" of the shells 2, 3 at 7. Each of the gripper shells 2, 3 has a side wall in the upper area

2' or 3' to the opposite side wall 2" or 3" has a continuous cross member 8, 9, in which bushings 10, 11, which are preferably hardened, are arranged at right angles to the opposite side wall and serve to accommodate preferably hardened support bolts 14. The support bolts 14 can be locked via washers 15 with locking pins 16 in the assembled state of the arrangement.

The grab shell assembly 1 is received by a shell carrier head 17, which forms the lower end of a vertical shell carrier tube 18, the upper part of which is closed with a connection flange 19, which is screwed to a flange 20 of the rotator 21 arranged above it and connected to the flange 19. The rotator 21 is connected to the boom arm of the excavator and enables the tube with the shell carrier to be rotated about its axis. 22 is the rotator connection and hydraulic distributor.

Two bearings 23 and 24 are arranged diametrically opposite one another on the shell support tube 18, which accommodate the fastening points 25, 26, which represent the mount for the hydraulic cylinders 27, 28. The piston rods 29, 30 of the hydraulic cylinders 27, 28 are fastened with their ends 31, 32 to bearing points 33, 34, which are simultaneously the bearing points for the two support arms 35, 36, which in turn are connected to one another in a common bearing point 37 for synchronization.

The support arms 35, 36 are provided with recesses 38, 39, which are designed in such a way that they encompass the cross members 8, 9, in the case of the special embodiment they are U-shaped in cross section. The bearings 40, 41 and 42, 43 have holes 44, 45, which, when the clamshell grab is assembled, are aligned with the holes 12, 13 of the cross members 8, 9 with bushings 10, 11. The holes 12, 13 of the bushings 10, 11 are aligned with the holes 44, 45 when the grab is assembled.

List of reference symbols

1 gripper shell set

2, 3 .... Gripper shells

4, 5 .... facing open sides of the shells (cutting edges)

6 Locking

7 Fixing screws 8, 9 Crossbars

10, 11 sockets

12,13 Hole for traverses

14 support bolts

15 Washer

16 Locking pin

17 Shell carrier head

18 Shell support tube 19,20 Connection flanges

21 Rotator

22 hydraulic distributors

23, 24 Bearings for hydraulic cylinders

25,26 Bearing bolt

27, 28 Hydraulic cylinder

29, 30 Piston rods

31,32 Rod ends

33,34 Storage Boizen

35, 36 Support arms

37 Forced guidance of the support arms

38, 39 Mounting for traverses in the support arms

40, 41, 42, 43 Positions of the recording

44, 45, 46, 47 holes

Claims (6)

Protection claims 1. Two-shell grab for hydraulic lifting devices, with a head-like shell carrier which has support arms which accommodate the two shells, a shell carrier tube, to the lower end of which the shell carrier is attached and the upper end of which is designed as a rotator, and with working cylinders which are articulated between flanges at the upper end of the shell carrier tube and the support arms and which can be actuated to open and close the grab shells, characterized in that the support arms (35, 36) which are articulated on the shell carrier (17) and can be pivoted by the working cylinders (27, 28) have recesses (38, 39) which are open at the bottom, that crossbars (8, 9) are attached to the grab shells (2, 3) which are designed so that they fit into the recesses (38, 39), and that in the assembled state the crossbars are fixed in the recesses (38, 39). (14, 15, 16) are. 2. Clamshell grab according to claim 1, characterized in that the recesses (38, 39) are downwardly open rectangular or inverted U-shaped recesses on transverse bearings of the support arms (35, 36). 3. Two-shell grab according to claim 1 or 2, characterized in that the inverted U-shaped recesses (38, 39) are designed as bearings (40, 41, 42, 43) on both sides of the respective support arm (35, 36), which extend between the vertical walls of the shell carrier (17), and that the cross members (8, 9) which are fixed in the projections (40, 41, 42, 43) extend through the shells (2, 3) and are firmly connected to the insides of the side walls of the shells (2, 3). 4. Clamshell grab according to one of claims 1 - 3, characterized in that the cross members (8, 9) between the shell side walls (2', 2", 3', 3") accommodate bushings (10, 11) the axis of which runs transversely to the axis of the cross members, and that the bushings are provided for receiving support bolts (14) which support the bearings (40, 41, 42, 43) are enforced and secured. 5. Clamshell grab according to one of claims 1-4, characterized in that the mutually facing open sides (4, 5) of the shells (2, 3) have securing elements (6) on the side walls (2', 2"', 3', 3") for placing the bearings (40, 41, 42, 43) of the shell carrier (17) on the cross members (9, 10). 6. Clamshell grab according to claim 5, characterized in that the securing elements (6) are designed as plates which are fastened to the side walls (2', 2", 3', 3") of the grab shells when the grab shells are closed and which determine the perfect position of the grab shells for picking up by the cross members.