GB1570862A

GB1570862A - Gripper for loads

Info

Publication number: GB1570862A
Application number: GB384978A
Authority: GB
Original assignee: Kernforschungsanlage Juelich GmbH
Current assignee: Forschungszentrum Juelich GmbH
Priority date: 1977-02-04
Filing date: 1978-01-31
Publication date: 1980-07-09
Also published as: FR2379467B1; FR2379467A1; BE863063A; DE2704670B2; DE2704670C3; DE2704670A1

Description

(54) GRIPPER FOR LOADS (71) We, KERNFORSCHUNGSAN LAGE JULICH GESELLSCHAFT MIT BESCHRANKTER HAFTUNG, of Postfach 1913, 517(1 Julich, Federal Republic of Germany, a Body Corporate organised according to the laws of the Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed. to be particularly described in and by the follow m statement: The invention relates to a gripper for loads, notably for the lifting of heavy leads, with two gripper arms, wherein the pulling force acting to raise the load is diverted partly into a force acting laterally relatively to the load by means of a pivot point.

Grippers of this kind are known in which the two gripper arms are mounted on a common pivot point in the manner of tongs, and those portions of the gripper arms which are situated above the pivot point are connected by way of further pivot points with link elements on whose common additional pivot point for pulling force acts.

Depending on the extent of opening of the gripper, the link elements and the upper portions of the gripper arms together form a parallelogram of variable shape. This makes handling of the gripper difficult and also dangerous for the operator more especially when attaching the gripper to the load, since fingers, hands or arms may become caught when opening or closing the gripper. In addition. it is a disadvantage when this known gripper that - depending on its design - parts of the gripper project appreciably beyond the outlines of the load in the opened state of the gripper, and thus it is difficult or even impossible to set down loads closely adjacent one another or to grab loads which are packed closed together.

According to one aspect of this invention, there is provided a gripper for loads with first and second gripper arms, wherein pulling force is applied to each of the gripper arms to raise the load and is partly diverted into a force acting laterally relatively to the load through the agency of a pivot point, characterised in that between the two gripper arms there is provided an intermediate element which holds the two gripper arms spaced apart, the pivot point allowing pivoting movement of the first gripper arm being situated at one end of the intermediate element, and the second gripper arm being connected rigidly to the other end of the intermediate element, and the portion of the mobile gripper arm situated above the pivot point has an inwardly directly bend.

As a further very advantageous feature of the above gripper, for better conversion of the pulling force into the force acting laterally relatively to the load, there is preferably provided a spacer element the two ends of which are respectively connected pivotably each to the upper ends of the respective gripper arms, there being an intermediate link between the mobile first gripper arm and the end of the spacer element connected therewith, the intermediate link being pivotably connected both with the spacer element and with the said first gripper arm.

In a second aspect of the invention there is provided a gripper for loads having first and second gripper arms with respective mutually facing gripping portions to receive a load between them, and an intermediate element extending between the arms and holding them spaced apart from one another, the first gripper arm having connection means at a location spaced from its gripping portion for the application of pulling force to the arm, the intermediate element being pivotalbly attached to the first gripper arm at a pivot point between its gripping portion and the connection means, the second gripper arm being rigid with the intermediate element and connection means being provided on or proximate the second gripper arm for the application of a pulling force thereto, the portion of the first gripper arm extending from the pivot point to the first arm's connection means for application of pulling force having a bend inwardly towards the other gripper arm so that application to the gripper arms of a pulling force acting generally away from the load will urge the gripping portions laterally towards each other for gripping the load between them.

It has been found very advantageous for the intermediate element to be adjustable in length, so that the gripper according to the invention can be adapted to the dimensions of the load in question, and where there is a spacer element for this also to be adjustable in length, so that its length can be adapted to that of the intermediate element. By adjusting the length of the u intermediate element the two gripper arms may be given the necessary spacing from one another for gripping the load, so that it is not necessary when gripping the load to move the gripper arms wide open to engage the load. This promotes safety when using the gripper and furthermore makes it possible to arrange loads closer together.

In use, a gripper embodying the invention, suspended on pull ropes or wires is advantageously guided over the load by the person operating it by means of the intermediate element and the mobile gripper arm and then, in order to apply the gripper to the load, it is simply necessary to pivot the mobile gripper arm slightly. The risk to the operator in this kind of operation is considerably reduced since with a gripper embodying the invention only one gripper arm is mobile, and, because of the fixed spacing of the gripper arms, the gripper cannot close in tongs fashion.

It is convention for a handle to be provided on the intermediate element for guiding the gripper and a handle may also be provided on the mobile gripper arm below the pivot point for pivoting this gripper arm and for additional guiding of the gripper. This makes it still easier to operate the gripper.

A convenient constructional example of a gripper in accordance with the invention is shown in diagrammatic manner in the drawings, and will be discussed in detail hereinafter: In the drawings, Figure 1 shows an elevation of the gripper, Figlzre 2 a side view of the gripper of Figure 1.

As figure 1 shows, the gripper has a first, mobile, gripper arm 1, and a second gripper arm 2. There is provided between the two gripper arms 1 and 2 an intermediate element which holds the two gripper arms spaced and which comprises two tubular portions 3a and 3b which can be inserted one into the other. These two portions can be connected together to constitute different overall lengths, being connected securely together by means of a pin 4 and a bolt constructed as a handle 5, these being inserted through corresponding holes in the two tubular portions of the intermediate element.

The arms 1, 2 are provided with mutually facing gripping portions to bear on a load positioned between them. Each arm has a pivot point 12, 13 providing connection means to which, in use, a pulling force is applied. The gripper arm 2, is connected rigidly to one end of the tubular portions, 3a, of the intermediate element whereas the gripper arm 1, is connected pivotably to the opposite end of the portion 3b at the pivot point 6. In each case the intermediate element is connected to the arm at a position between the arm's gripping portion and its location 12 or 13 for the application of pulling force. As can be seen in the drawing, the upper part of the gripper arm 1, between the pivot points 6 and 12 has an inward bend towards the other arm.

The mobile gripper arm 1, has a handle 7 below the pivot point 6. This handle is in the form of a loop to be held by the hand of the operator, and serves for pivotally lifting the gripper arm 1, and at the same time for guiding the gripper.

In the constructional form of gripper shown in the drawings there is also provided a spacer element which consists of two sections 8a and 8b so as to be adjustable in length for adaptation to the length of the intermediate element 3a, 3b. The two sections 8a, 8b are securely connected together by means of a pin 4 and a ring bolt 9, these being inserted in corresponding holes in the two sections. One end of the spacer element is connected pivotably by way of the pivot point 10, an intermediate link 11 and pivot point 12 to the mobile gripper arm 1, and the other end of the spacer element is pivotably connected by way of the pivot point 13 to the rigid gripper arm 2.

As shown in the drawings, the spacer element 8a, 8b is connected to pull ropes (which are shown only sketchily in the drawings) to a ring 14 on which, in use, a pulling force acts. The ropes transmit the pulling force to connection means in the upper part of the spacer element (i.e. the holes therein to which the ropes are attached). The spacer element in turn transmits the pulling force to the pivot points 12, 13 and thus to the gripper arms. Because of the inward bend in the upper part of the arm 1 the pulling force acts to turn it around the pivot 6 and so urges its gripping portion laterally towards the gripping portion of the other gripping arm. Provided it is of suitable breadth. a load positioned between the gripping portions will then be gripped by them.

The gripper described above is suitable for the lifting of heavy loads and is capable of simple and reliable manipulation. It allows good guidance on application of the gripper to the load and also allows loads to be arranged close beside one another on a limited surface area as, for example, for the transportion of such loads.

WHAT WE CLAIM IS: 1. A gripper for loads with first and second gripper arms, wherein pulling force is applied to each of the gripper arms to raise the load and is partly diverted into a force acting laterally relatively to the load through the agency of a pivot point, characterised in that between the two gripper arms there is provided an intermediate element which holds the two gripper arms spaced apart, the pivot point allowing pivoting movement of the first gripper arm being situated at one end of the intermediate element, and the second gripper arm being connected rigidly to the other end of the intermediate element, and the portion of the mobile gripper arm situated above the pivot point has an inwardly directed bend.

2. A gripper according to claim 1, having a spacer element the two ends of which are respectively connected pivotably to the upper ends of the respective gripper arms, there being an intermediate link between the said first gripper arm and the end of the spacer element connected therewith, the intermediate link being pivotably connected both with the spacer element and with the said first gripper arm.

3. A gripper for loads having first and second gripper arms with respective mutually facing gripping portions to receive a load between them, and an intermediate element extending between the arms and holding them spaced apart from one another, the first gripper arm having connection means at a location spaced from its gripping portion for the application of pulling force to the arm, the intermediate element being pivotably attached to the first gripper arm at a pivot point between its gripping portion and the connection means, the second gripper arm being rigid with the intermediate element and connection means being provided on or proximate the second gripper arm for the application of a pulling force thereto, the portion of the first gripper arm extending from the pivot point to the first arm's connection means for application of pulling force having a bend inwardly towards the other gripper arm so that application to the gripper arms of a pulling force acting generally away from the load will urge the gripping portions laterally towards each other for gripping the load between them.

4. A gripper according to claim 3 wherein connection means are provided on the second gripper arm, at a location spaced from its gripping portion, for the application of pulling force to the arm and one end of the intermediate element is rigidly connected to the said second gripper arm at a point between its gripping portion and its connection means for application of pulling force, the opposite end of the said intermediate element being pivotably attached to the first gripper arm.

5. A gripper according to claim 3 or claim 4, having a spacer element pivotably connected at the connection means for the application of pulling force through the spacer element the pivotable connection to the first gripper arm being through an intermediate link situated between the said first gripper arm and the spacer element and pivotably connected both with the spacer element and with the said first gripper arm.

6. A gripper according to any one of the preceding claims wherein the intermediate element is adjustable in length.

7. A gripper according to claim 2 or claim 5 wherein both the intermediate element and the spacer element are adjustable in length.

8. A gripper according to any one of the preceding claims 1 to 4, wherein a handle is provided on the intermediate element.

9. A gripper according to any one of the preceding claims 1 to 5, wherein a handle is arranged on the first gripper arm at a point between the pivot point and the end of the gripper arm remote from the location of application of pulling force to the arm.

10. A gripper substantially as herein described with reference to the accompanying drawing.

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Claims

**WARNING** start of CLMS field may overlap end of DESC **.

1 the pulling force acts to turn it around the pivot 6 and so urges its gripping portion laterally towards the gripping portion of the other gripping arm. Provided it is of suitable breadth. a load positioned between the gripping portions will then be gripped by them.