GB2255070A

GB2255070A - Clamping device for stacks of bricks.

Info

Publication number: GB2255070A
Application number: GB9206239A
Authority: GB
Inventors: Rudolf Kollmub
Original assignee: Kinshofer Greiftechnik GmbH
Current assignee: Kinshofer GmbH
Priority date: 1991-04-05
Filing date: 1992-03-23
Publication date: 1992-10-28
Anticipated expiration: 2012-03-23
Also published as: DE9117258U1; GB9206239D0; GB2255070B

Abstract

A clamping device is provided with gripping arms displaceably mounted in parallel to each other on a central carrying member by means of legs (3, 4 and 5, 6) angularly connected therewith, said central carrying member being provided with an attaching means, and with a hydraulic piston-cylinder unit moving the gripping arms towards and away from each other. In order to create a simple and robust synchronising device, two piston-cylinder units (16, 18; 17, 19) are provided in parallel to each other, the cylinders (18, 19) of which are coupled to opposing end portions of the carrying member and the piston rods (16, 17) of which are each coupled to one gripping arm. The closed end side of one of the cylinders (19) and the exit side of the piston rod of the other cylinder (18) are connected with the pressure lines or return lines (35, 36) for the hydraulic fluid. The other closed end side and the other exit side of the piston rod of the cylinders are interconnected via a connection line (39). The cross-sectional area of the annulus of the cylinder chamber (37) belonging to one of the cylinders (19) and being connected with the connection line (39) substantially corresponds to the piston rod-free cross-sectional area of the cylinder chamber (38) belonging to the other cylinder (18) and being connected with the connection line (39). … <IMAGE> …

Description

1 1 CLAMPING DEVICE, PARTICULARLY A CLAMPING DEVICE FOR STACKS OF BRICKS

This invention relates to a clamping device, in particular to a clamping device for stacks of bricks, with gripping arms displaceably carried in parallel to each other on a carrying member by means of legs angularly connected therewith, said carrying member being provided with attaching means, and with a hydraulic piston-cylinder unit moving the gripping arms towards and away from each other.

There are known various designs of such kinds of clamping devices. The special problem existing for the known clamping devices is to achieve a synchronous action of the gripping arms with sufficiently large opening and closing movements. In order to ensure a synchronism of the gripping arms, expensive mechanical means are required which effect the necesú.ary synchronism by means of ropes, chains or linkages.

In the clamping device for a stack of bricks of the kind mentioned above and known from the published German Application 22 03 845 the respectively oppositely directed parts of the legs of the gripping arms are connected via ropes running over rope pulleys and producing the desired synchronism.

The known synchronizing devices are of a high technical expenditure and, moreover, can cause troubles as they are subject to additional wear.

Therefore the object of the invention is to develop a clamping device according to the generic part of the claim, which is provided with a synchronizing device of a simple and rugged nature.

Said object is solved according to the invention by a clamping device of the generic type in that two piston-cylinder units are provided in parallel to each other, the cylinders of which are coupled to opposing end portions of the carrying member and the piston rods of which are each coupled to one gripping arm, that the closed end side of one of the cylinders and the exit side of the piston rod of the other cylinder are connected with the pressure lines or return lines for the hydraulic fluid, that the other closed end side and the other exit side of the piston rod of the cylinders are interconnected by a connection line, and that the cross-sectional area of the annulus of the cylinder chamber belonging to one of the cylinders and being connected with the connection line substantially corresponds to the piston rod-free cross-sectional area of the cylinder chamber belonging to the other cylinder and being connected with the connection line. In the clamping device according to the invention, the two cylinders opening and closing the gripping arms are interconnected by a connection line in such a manner that the required synchronism is ensured. In order to guarantee said synchronism, the two cylinder chambers interconnected via the connection line show identical cross-sectional areas, which is achieved by the fact that the cylinder, into the closed end side of which the connection line is led, has a correspondingly smaller diameter. As the hydraulic fluid displaced out of one cylinder chamber, respectively, is led through the connection line into the other cylinder chamber, the pistons of both cylinders are, so to speak, Interconnected by means of a hydraulic linkage, so that due to the identical cross-sectional areas of the cylinder chambers interconnected by means of the connection line the pistons perform equal-sized movements in opposite directions. The wear of the synchronizing device according to the invention is rather low, since apart from the pistons no other moving mechanical parts are provided. By the described oppositely oriented coupling of the two cylinders, large opening and closing movements can be achieved with small piston strokes, wherein the clamping device as a whole shows a rugged design, as the opening and closing forces are merely produced hydraulicly.

It is of course also possible that the piston-cylinder units being arranged in parallel to each other are turned around such that the cylinders thereof are coupled to the gripping arms and their piston rods to the central carrying member.

One embodiment of the invention will be described in the following with reference to the accompanying drawings, in which Fig. 1 is a perspective lateral view of a clamping device for a stack of bricks, and Fig. 2 is a sectional view of the clamping device for a stack of bricks taken on line B-B of Fig. 1.

The clamping device 1 consists of a central carrying member 2 at the centre of which an attaching means (not shown), preferably an attaching means combined with a torque motor, is mounted. In the carrying member 2, the two parallel legs 3,4 and 5,6, respectively, of the gripping arms 7,8 and 9,10 are guided for longitudinal displacement thereof, the gripping arms 7,8 and 9,10 being provided with gripping rails 11, 12 at their lower ends which connect the gripping arms 7,8 and 9,10 in a frame-like manner. The legs 3,4 and 5,6 are connected with the associated gripping arms 7,8 and 9,10 approximately at right angles.

The upper end portions of the gripping arms 7,8 and 9,10 and/or the legs 3,4 and 5,6 are interconnected by means of the crosspieces 14,15. To the crosspieces 14,15 the piston rods 16,17 are coupled, the cylinders 18,19 of which are coupled to the carrying member 2 by the pivot pins 20,21. The carrying member 2 consists of a frame which is provided with two tubular parallel guide means 23,24 and 25,26 for the legs 3,4 and 5,6, respectively, which are interconnected by means of transversely extending traverses 27,28. Furthermore, on the traverses there are mounted the holding elements 30,31 carrying the cylinders 18,19.

The cylinder chamber 32 of the cylinder 19, which is free from a piston rod, and the cylinder chamber 33 of the cylinder 18 through which the piston rod 16 extends are provided with the supply lines 35,36 which, in accordance with the direction of movement of the gripping arms, are pressurized or lead to the tank.

The opposing cylinder chambers 37,38, through the cylinder chamber 37 of which the piston rod 17 extends, are interconnected via the connection line 39. In order to guarantee the synchronism, the cylinder chambers 37, 38 show cross sections equal in area. Therefore, the diameter of cylinder 18 is smaller than that of cylinder 19 so that the space occupied by the piston rod 17 is made up for.

l:i:i:11:1"il

Claims

Claim:

Clamping device, preferably a clamping device (1) for a stack of bricks, with gripping arms (7,8,11;9,10,12) displaceably mounted in parallel to each other on a central carrying member (2) by means of legs (3,4;5,6) angularly connected therewith, said central carrying member (2) being provided with an attaching means, and with a hydraulic piston-cylinder unit moving the gripping arms towards and away from each other, characterized in that two piston-cylinder units (16,18;17,19) are provided in parallel to each other, the cylinders (18,19) of which are coupled to opposing end portions of the carrying member (2) and the piston rods (16,17) of which are each coupled to one gripping arm (7,8,11;9,10,12), that the closed end side of one of the cylinders (19) and the exit side of the piston rod of the other cylinder (18) are connected with the pressure lines or return lines (35,36) for the hydraulic fluid, that the other closed end side and the other exit side of the piston rod of the cylinders are interconnected by a connection line (39), and that the cross-sectional area of the annulus of the cylinder chamber (37) belonging to one of the cylinders (19) and being connected with the connection line (39) substantially corresponds to the piston rod-free cross-sectional area of the cylinder chamber (38) belonging to the other cylinder (18) and being connected with the connection line (39).

Claim 2:

A clamping device substantially as herein before described with reference to, and as illustrated in, the accompanying drawings.