IE45710B1 - Handling devices - Google Patents

Abstract

Joint in which the bellows is formed of a stack of sections each associated with a telescopic element. The two telescopic elements 1 and 2 are surrounded by the sections of bellows 3 and 4 sealingly connected to the ring 5. The element 4 is likewise connected to the protective cover 9 and the element 3, to the cap 7, close to The coupling 10 is fixed to the sliding and protective cap 11.

Description

This invention relates to handling devices.

Remotely-controlled telescopic arms provided with grippers, such as are used in hermetically sealed radioactive hot cells, must be sealed against the cell wall, especially to prevent radioactive particles or gases from leaving the cell.

This can be done, for example, by sealing the moving parts and the housing of the telescopic arm at the place where it extends through the cell wall. The disadvantage of this method is that the gripper arms have to be replaced periodically as a result of inevitable contamination, and this increases the amount of time required for dismantling or assembly and the length of the inoperative periods of the system.

Another method of sealing a telescopic arm is to enclose it in a flexible bellows, for example of rubber or plastics, which screens the arm against radioactive radiation and contamina tion.

This method in itself is relatively simple and cheap, but has considerable disadvantages in operation owing to the sensitivity of the bellows and the impairment of visibility resulting from the large overall bellows diameter. In the case of multiple telescopic arms there may also be an undesirable reduction in the sensitivity of the arm since its moving parts move with substantial friction against the asymmetri45710 - 3 cally contracted bellows. This may also damage the bellows.

Additional damage may be caused since the bellows, in the case of both a single and a multiple telescopic arm, contracts non-uniformly and remains suspended from the tele5 scopic units, and may thus tear when the unit is extended.

The aforementioned disadvantages are largely obviated by a handling device comprising the bellows seal system for telescopic arms according to the invention, as hereinafter exemplified.

According to the present invention there is provided a handling device having a gripper attached to an arm, the arm comprising a plurality of members which are adapted to telescope with one another, wherein each of the members is covered and protected from gaseous or particulate contamina13 tion by ar individual flexible bellows unit.

Preferably each bellows unit is secured circumferentially in gas-tight manner to a ring, which is itself secured to that end of a member at the point at which the member which the bellows unit protects telescopes into its neigh20 bouring member. It is also preferred that each bellows unit and corresponding ring are releasable integrally from the corresponding member. For this purpose the ring is conveniently secured to the member by a rotatable joint comprising a plurality of balls engaging a ball race.

In order to improve the visibility of the gripper to the operator one or more of the bellows units can be of smaller diameter at its outer end than at its inner end.

In a handling device according to the present invention only the bellows portion corresponding to the telescopic member in operation is retracted or extended, instead of the 45*710 - 4 entire bellows as in known 'systems. This reduces the total mass of bellows units which are moving, increases the sensitivity and accuracy of the telescopic arm and reduces the friction of the bellows on the telescopic unit. In short, the device according to the invention, as exemplified hereafter, substantially eliminates damage to the bellows. Another advantage is that the diameter of each bellows portion can be varied in accordance with the diameter of its associated telescopic member so as to provide a close fit thereover, thus improving visibility for the operator.

According to another preferred feature of the invention, the end of the bellows unit whioh is adjacent the gripper is secured in a gas-tight manner to that end of the corresponding member adjacent the gripper, for example by clamping the end of the bellows unit to a bell-shaped protective cap attached to the gripper. Furthermore, the opposite end of the gastight column of bellows unit may be rotatably secured to a protective cap attached to the stationary part of the associated telescopic member and is in turn connected by a ring and clamp to a stationary gas-tight protective hood.

The bell-shaped protective cap ensures that when the outermost telescopic, member is retracted, the corresponding bellows portion cannot move so far over the gripper as to hinder its operation and risk the bellows being damaged.

The ends of the bellows column can be sealed in a simple manner by the gas-tight clamping of the bellows over the gripper at one end thereof, and by securing in a gas-tight manner to the stationary hood at the other end thereof.

An embodiment of the invention will now be described in detail by way of example with reference to the accompanying drawings in which:45710 - 5 Figure 1 is a diagram of a handling device in accordance with the invention having two bellows portions on a double telescopic arm, and Figure 2 is an enlarged view, partly in cross-section, of part of the device shown in Figure 1 and showing in particular, the junction between the bellows portions.

Figure 1 shows two telescopic members 1, 2 surrounded by bellows portions 3, 4 shown in cross-section. Bellows portions 3, 4 are secured together in gas-tight manner by a ring 5, the two bellows portions thus forming a column.

Portion 3 of the bellows column, at its end adjacent the gripper 6, is clipped in gas-tight manner to a bellshaped protective cap 7. At the end remote from gripper 6, the bellows column is secured in gas-tight manner by ring 8 to a stationary hood 9. Bellows portion 3 is held against gravitational force by ring 5, which is rotatably secured to a protective cap 11 by a joint 10 comprising a plurality of ball 10a engaging a ball race, which can be released by remote control. Cap 11 also contains mechanical and electrical operating components (not shown) for the telescope and guides them so that they do not touch the bellows portions. The protective cap 7 (shewn in Figure 2) serve the same supporting purpose.

The end of the bellows portions 3 which are adjacent the gripper 6 has a diameter smaller than the end which is adjacent ring 5. This reduces the mass of bellows which is in motion when the telescope is operated and also improves visibility near the gripper.

Figure 2 includes a cross-section showing a ring disposed at the junction between the two bellows portions. *5710 - 6 Rings 5 and 8 have identical grooves 8a on their outer periphery, along which the ends of bellows portions 3, 4 or stationary hood are pushed and secured by hose clips (not shown) of suitable diameter. The rotatable joint 10 is secured as follows. The balls, which bear resiliently on the periphery of the protective cap 11, engage a ball race 8b on the inner surface of ring 8. Ring 8 can for example by removed from cap 11 by a remotely-controlled tool (not shown), whereupon balls 10a are forced radially back so as to release the ring.

The bell-shaped protective cap 7 is designed to ensure that when the telescopic unit is retracted bellows portion 3 cannot move over housing 6a or the gripper 6 shown in Figure 1.

In the embodiment illustrated the protective cap 7 is made of a suitable plastics material and is secured by a hose clip (not shown) to the gripper housing 6a and also to the end of bellows portion 3.

The groove 12 in the housing 6a increases the sealing20 tightness of the junction by giving a better purchase to the end of the bellows.

Claims (8)

1. A handling device having a gripper attached to an arm, the arm comprising a plurality of members which are adapted to telescope with one another, wherein each of the members is covered and protected from gaseous or particulate contamina tion by an individual flexible bellows unit.

2. A device as claimed in Claim 1 wherein each bellows unit is secured circumferentially in gas-tight manner to a ring.

3. A. device as claimed in Claim 2 wherein the ring is secured to that end of a member at the point at which the Bieiaber which the bellows unit protects telescopes into its neighbouring member.

4. A device as claimed in Claim 3 wherein each bellows unit and corresponding ring are releasable integrally from their corresponding member.

5. A device as claimed in Claim 4 wherein the ring is secured to the raeniber by a rotatable joint comprising a plurality of balls engaging a ball race.

6. A device as claimed in any one of the preceding claims wherein the end of the bellows unit adjacent the gripper is secured in a gas-tight manner to that end of the corresponding member adjacent the gripper.

7. A device as claimed in any one of the preceding claims wherein the diameter of each bellows unit is varied in accordance with the diameter of its corresponding member so as to provide a close fit thereover.

8. A handling device as claimed in claim 1 substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.