GB2273546A

GB2273546A - Automatic machine for locking elastic seals fitted on to tubs of washing machines

Info

Publication number: GB2273546A
Application number: GB9320082A
Authority: GB
Inventors: Francesco Tesan; Del Bianco Sergio Calami; Puppo Antonio Del
Original assignee: Zanussi Elettrodomestici SpA
Current assignee: Electrolux Zanussi Elettrodomestici SpA
Priority date: 1992-12-21
Filing date: 1993-09-29
Publication date: 1994-06-22
Anticipated expiration: 2013-09-29
Also published as: GB2273546B; DE4328900A1; IT1259241B; ITPN920095A0; FR2699442B1; ES2076876B1; FR2699442A1; ES2076876A2; ITPN920095A1; GB9320082D0; ES2076876R

Description

2273546 AUTOMATIC MACHINE FOR LOCKING ELASTIC SEALS FITTED ON TO TUBS OF

WASHING MACHINES The present invention relates to a machine for automatically locking elastic seals which are pre-fitted on to tubs of washing machines, in particular front-loading clothes washing machines.

As is known, front-loading clothes washing machines generally comprise a substantially cylindrical washing tub, a front wall of which is provided with an opening which has to be connected by means of a flexible annular seal, normally of the bellows type, to a corresponding opening provided in the casing of the machine.

In general the flexible seal is fitted on to the is edge of the opening of the tub and then has to be locked in position by means of a resilient spring ring or the like. Hitherto that locking operation has been effected manually and must be completed with a certain degree of precision in such a way as to ensure effective hydraulic sealing integrity of the seal itself which in use of the machine is subjected to severe mechanical stresses. In addition when the resilient locking ring is mounted on the seal it is necessary to seek to avoid possible stretching thereof which could prejudice the above-mentioned hydraulic sealing integrity of the arrangement.

To sum up, the above-mentioned locking operation is relatively critical, laborious and costly on an industrial scale. In practice it has been found that manually locking the bellows-type seal gives rise to an undesirably high number of defective components.

The aim of the present invention is to provide an automatic machine for fast, precise and correct locking of flexible seals fitted on to tubs of washing machines.

According to the present invention, there is provided an automatic machine for locking elastic seals 2 fitted on to tubs for washing machines, or portions of same, each seal being capable of being locked in position by means of a resilient spring ring or the like, the machine comprising:

a locking station for successively receiving said tubs with the respective seals; fee ' der means for successively conveying a plurality of said rings to a collection station; and an extensible robotised arm provided with a gripping head and capable of moving between the collection station and the locking station to take each ring from the collection station and carry it into the locking station in an elastically enlarged condition; said gripping head being capable of positioning the ring around the respective seal and releasing it in such a way as elastically to lock the seal on to the associated tub.

The features and advantages of the invention will be clearly apparent from the following description given solely by way of non-limiting example with reference to the accompanying drawing in which: Figure 1 diagrammatically shows the main components of the machine in accordance with a preferred embodiment of the invention, in a first operative condition; 25 Figure 2 shows a detail of the machine in Figure 1, in a second operative condition; and Figure 3 shows the machine of Figure 1 in a third operative condition. Referring to the Figures, the machine primarily comprises an extensible robotised arm 4 which for example is disposed vertically and which is displaceable along a horizontal rail or track 5 between a locking station 6 and a collection station 7. The machine further comprises a slide-type feeder 8 disposed above the collection station 7 and associated with an automatic intermittent advance 3 device 9. The latter can be of any per se known type; it is for example mounted on the track 5 and is operable to advance along the slide member 8, one at a time, a plurality of resilient locking rings 10 which are provided on the feeder. Consequently each ring 10 is allowed to drop from time to time under the force of gravity at the collection station 7.

The collection station 7 is in substance formed by a hopper associated with a flat horizontal base 13; the hopper is formed by a plurality of sectors 11 which are disposed side-by- side and hinged to the station 7 so as to be capable of opening out from a normal rest position (Figures 1 and 3) to an open position (Figure 2), overcoming the force of return springs 12 or the like. As shown in is Figure 1, when a resilient ring 10 is dropped from the feeder 8. it is collected by the hopper 7 to be deposited horizontally on the base 13; under those conditions, the normal tendency of the resilient spring rings 10 to assume a substantially regular circular configuration is put to use.

The locking station 6 is capable of supporting from time to time a washing tub 14 or a portion thereof which is provided with an opening, on the edge of which a flexible seal 15, for example of bellows type, is fitted in known manner. In particular the tub 14 is disposed at the station 6 with the seal 15 facing towards the robotised arm 4, that is to say upwardly.

The robotised arm 4 whose movements are produced for example by a per se known pneumatic andlor mechanical system substantially comprises a gripping head 16 which can be lowered and raised by the arm 4 with a piston movement. In particular the gripping head 16 comprises a plurality of fingers 17 which are distributed around a circle and pivotally mounted on a plate 18 which is axially movable and which also carries a plurality of pusher members 20. The latter are distributed around the circumference of the 4 plate 18 and each correspond to a sector 11 of the hopper 7. The head 16 further comprises a plurality of pistons 19 (which for example are actuated pneumatically) also distributed around the plate 18 around a circle substantially corresponding to the dimensions of the resilient rings 10.

In operation, after the feeder 8, 9 has deposited a ring 10 on the base 13 of the collection station 7 (Figure 1), the robotised arm 4 is displaced along the rack 5 to move into position above the station 7. At that point (see Figure 2) the head 16 is moved downwardly so that the pusher members 20 cause outward spreading movement of the sectors 11 of the hopper 7 in such a way as to permit the fingers 17 to bear against the base 13 where they are surrounded by the ring 10. The fingers 17 are then opened out to elastically engage the ring 10 with a predetermined movement which causes slight regular elastic enlargement of the ring.

The gripping head 16 is then raised with the ring 10 and the arm 4 is moved again into a position corresponding to the locking station 6, above the tub 14. Obviously as soon as the hopper 7 is disengaged from the gripping head 16 the sectors 11 move back into the rest position shown in Figure 1 to receive a subsequent ring 10.

At that point the gripping head 16 is moved downwardly towards the tub 14 where the fingers 17 surround the seal 15 (Figure 3 where the seal is not shown for the sake of simplicity), positioning the ring 10 at a position corresponding to a suitable seat with which the seal 15 is provided in per se known fashion (not shown). The fingers 17 then retract slightly inwardly and upwardly to release the ring 10 which instead is engaged by the pistons 19. The pistons 19 in fact move downwardly in a suitable fashion to prevent upward movement of the ring 10 which therefore resiliently contracts, locking the seal 15 in position.

The pistons 19 are retracted and the gripping head 16 moves upwardly, permitting the tub-seal assembly 14, 15 to be replaced by another tub on which a seal to be locked in the above-described manner is pre-fitted.

The operating cycle of the machine can then be repeated without substantial dead periods, as described hereinbefore.

It will be apparent from the foregoing description that the machine according to the present invention makes it possible to lock the seals 15 in position in a fast, precise and completely automatic manner. Consequently the percentage of defects in the fitting operation on an industrial scale is also drastically reduced.

It will be appreciated that the described machine may be the subject of many modifications which fall within the scope of the invention.

6

Claims

An automatic machine for locking elastic seals fitted on to tubs for washing machines, or portions of same, each seal being capable of being locked in position by means of a resilient spring ring or the like, the machine comprising:

a locking station for successively receiving said tubs with the respective seals; feeder means for successively conveying a plurality of said rings to a collection station; and an extensible robotised arm provided with a gripping head and capable of moving between the collection station and the locking station to take each ring from the collection station and carry it into the locking station in an elastically enlarged condition; said gripping head being capable of positioning the ring around the respective seal and releasing it in such a way as elastically to lock the seal on to the associated tub.
2. An automatic machine according to claim 1 wherein said feeder means comprise a slide-type feeder carrying a plurality of said resilient rings and capable of conveying same by dropping towards the subjacent collection station by way of an intermittent advance device.
3. An automatic machine constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying 15 drawings.

3. An automatic machine according to claim 2 wherein the collection station comprises a hopper formed by a plurality of sectors which can be opened out into an open position against the force of spring return means.

4. An automatic machine according to claim 1, 2 or 3 wherein said gripping head comprises a plurality of pivotally mounted fingers which are distributed around a 7 circle and which are capable of opening out to engage the ring disposed on the collection station and retracting to release the ring at the locking station, the gripping head further comprising piston means capable of extending when said fingers are retracted in such a way as to hold in position the ring which consequently resiliently contracts to lock the respective seal on the associated tub.

5. An automatic machine according to claim 3 or claims 3 and 4 wherein said gripping head comprises pusher means which, when the robotised arm is at the collection station are operable to engage said sectors in such a way as to push them into an opened-out position and to permit said gripping head to engage the resilient ring disposed on the collection station.

6. An automatic machine constructed and arranged to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

Amendments to the claims have been filed as follows 1. An automatic machine for locking elastic seals fitted on to tubs for washing machines, or portions of same, each seal being capable of being locked in position by means of a resilient spring ring or the like, the machine comprising:

a locking station for successively receiving said tubs with the respective seals; feeder means for successively conveying a plurality of said rings to a collection station, the collection station comprising a hopper formed by a plurality of sectors which can be opened out into an open position against the force of spring return means, the feeder means comprising a slide-type feeder carrying a plurality of said resilient rings and capable of conveying same by dropping towards the subjacent collection station by way of an intermittent advance device; and an extensible robotised arm provided with a gripping head and capable of moving between the collection station and the locking station to take each ring from the collection station and carry it into the locking station in an elastically enlarged condition; said gripping head being capable of positioning the ring around the respective seal and releasing it in such a way as elastically to lock the seal on to the associated tub, said gripping head comprising pusher means which, when the robotised arm is at the collection station are operable to engage said sectors in such a way as to push them into an opened-out position and to permit said gripping head to engage the resilient ring disposed on the collection station.

2. An automatic machine according to claim 1, wherein said gripping head comprises a plurality of pivotally mounted fingers which are distributed around a circle and which are capable of opening out to engage the ring disposed on the collection station and retracting to release the ring at the locking station, the gripping head further comprising piston means capable of extending when said fingers are retracted in such a way as to hold in position the ring which consequently resiliently contracts to lock the 10 respective seal on the associated tub.