GB1559826A

GB1559826A - Lock for door latching device

Info

Publication number: GB1559826A
Application number: GB35354/75A
Authority: GB
Original assignee: Greenpoint Controls & Elements
Current assignee: Greenpoint Controls & Elements
Priority date: 1976-08-23
Filing date: 1976-08-23
Publication date: 1980-01-30

Description

(54) LOCK FOR DOOR LATCHING DEVICE (71) We, GREENPOINT CONTROLS AND ELEMENTS LIMITED, a British Company of Kings Worthy, Winchester, Hampshire, S023 7QH, 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 following statement: This invention relates to a washing machine including a lock for a latching device on the washing machine door. It is particularly suitable for locking the loading door before spinning the tub to remove water from the washing.

The invention provides a washing machine comprising a tub; a tub door; a latching device for said door; a lock for said latching device, said lock comprising a diaphragm which is moveable between first and second positions, said diaphragm being supported in a housing and dividing the housing into respective subchambers, a member connected to the diaphragm for locking said latching device when the diaphragm is in its second position and means for providing a controlled air leak for one of said subehambers whereby the diaphragm is restorable from its second to its first position over a predetermined period; the washing machine also comprising a drain pipe; a pump for removing water from the tub through said drain pipe whereby a head of water is provided in said pipe; an air trap connected to said pipe; and means connecting said air trap to one of said subchambers whereby said head of water in the drain pipe compresses the air in said air trap to cause the diaphragm to move from its first to its second position.

The subchamber connected to the air trap may contain a non-return valve which admits air from the air trap, said controlled air leak bypassing said non-return valve.

Suitably, the non-return valve is biassed towards a seating defined by an annular shoulder and said controlled air leak comprises a duct in said shoulder with an adjustable restriction.

Alternatively, the subchamber, which is not connected to the air trap, is connected to a non-return valve which communicates with the atmosphere. In this case, said controlled air leak comprises an adjustable restrictor which communicates between the atmosphere and the subchamber which is not connected to the air trap.

In either case, the air pressure is maintained during a period in which water is extracted from the machine and, at the end of this period, the controlled leak allows air to escape over a period which is long enough to allow the tub to cease rotating or to reach a reduced safe speed.

Examples of the invention are described with reference to the accompanying drawings, which illustrate cross-sectional views, and in which: Fig 1 illustrates a first embodiment, and Fig 2 illustrates a second embodiment.

Fig 1 illustrates means for locking a latching device on a washing machine door. It comprises upper and lower cups 1 and 2 secured together by a clip 3 to clamp the periphery of a diaphragm 4. A locking member 5 has a base 6 attached to the centre of diaphragm 4. A return spring 7 urges the diaphragm 4 towards cup 2.

Cup 2 defines a chamber 8 bounded by an annular shoulder 9 and a non-return valve 10. A spring 11 closes valve 10 and is supi ported on a spider 12 which bridges cup 2.

Chamber 8 communicates, via a duct 13, to a port 14. Port 14 is covered by an adjusting screw which is sealed after being set, as explained below. Chamber 8 also communi- cates with a pressure inlet 16.

The construction of a washing machine is such that, during spinning of its tub. a pump is removing water through a drain pipe. The pump is capable of lifting water above the maximum level in the tub during washing. Therefore, during spinning a head of water is maintained in the drain pipe which may be used to derive air under pressure to operate valve 10. Preferably, inlet 16 is connected via an air trap to a junction in the drain pipe. When a head of water is present, air in the trap is compressed and it enters chamber 8 to open valve 10. This moves diaphragm 4 upwardly whereby the locking device or plunger 5 moves to a position to lock a latching device (not shown) which normally secures the washing machine door. When all the water has been removed by spinning, the standing head collapses and air escapes through port 14 whereby the diaphragm 4 returns to its original position whereby the door can be unlatched. The time taken for air to leak through port 14 is selected such that the tub has either ceased rotating or has slowed to a safe speed.

An alternative embodiment is shown in Fig 2 wherein like parts are identified by similar reference numerals. However, in this case, the controlled leak defined by port 14 and screw 15 is in the upper cupl 1 and the chamber 8 is directly closed by diaphragm 4. A non-return valve 17 is also provided in the cup 1 to allow air to escape from chamber 18 to permit the diaphragm 4 to move upwards to displace the plunger 5. The plunger 5 is supported in openings 19, 20 respectively provided in a recessed portion 21 and a support 22; a flexible annular seal 23 prevents air escaping from chamber 18.

In the embodiment of Fig 2, valve 17 and the leak 14, 15 are isolated from the inlet to chamber 8 and therefore less susceptible to foreign matter. Operation is similar to the device described above except that air leaks from the atmosphere into chamber 18 when the standing head collapses.

In both of the above described embodiments, the pressure inlet 16 may be connected via an air trap to a junction in the drain pipe of the washing machine or to the tub such that a static head of water is present in the trap whilst the tub contains water. This static head compresses air in the trap to maintain the diaphragm 4 in a position to cause the locking member 5 to lock the door latching device of the machine.

The tub door cannot, therefore, be opened whilst it contains enough water to maintain the required air pressure. Under normal circumstances, this means that the tub door cannot be opened during a wash cycle.

WHAT WE CLAIM IS: 1. A washing machine comprising a tub; t tub door; a latching device for said door; a lock for said latching device, said lock comprising a diaphragm which is moveable between first and second positions, said diaphragm being supported in a housing and dividing the housing into respective subchambers, a member connected to the diaphragm for locking said latching device when the diaphragm is in its second position and means for providing a controlled air leak for one of said subchambers whereby the diaphragm is restorable from its second to its first position over a predetermined period; the washing machine also comprising a drain pipe; a pump for removing water from the tub through said drain pipe whereby a head of water is provided in said pipe; an air trap connected to said pipe; and means connecting said air trap to one of said subchambers whereby said head of water in the drain pipe compresses the air in said air trap to cause the diaphragm to move from its first to its second position.

2. A washing machine according to claim 1 wherein the subchamber connected to the air trap contains a non-return valve which admits air from the air trap, said controlled air leak bypassing said non-return valve.

3. A washing machine according to claim 2 wherein said non-return valve is biassed towards a seating defined by an annular shoulder and said controlled air leak comprises a duct in said shoulder with an adjustable restriction.

4. A washing machine according to claim 1 wherein the subchamber, which is not connected to the air trap, is connected to a non-return valve which communicates with the atmosphere.

5. A washing machine according to claim 4 wherein said controlled air leak comprises an adjustable restrictor which communicates between the atmosphere and the subchamber which is not connected to said air trap.

6. A washing machine according to claim 1 wherein said lock is substantially as herein described with reference to Fig.

1 of the accompanying drawings.

7. A washing machine according to claim 1 wherein said lock is substantially as herein described with reference to Fig. 2 of the accompanying drawings.

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. pipe. The pump is capable of lifting water above the maximum level in the tub during washing. Therefore, during spinning a head of water is maintained in the drain pipe which may be used to derive air under pressure to operate valve 10. Preferably, inlet 16 is connected via an air trap to a junction in the drain pipe. When a head of water is present, air in the trap is compressed and it enters chamber 8 to open valve 10. This moves diaphragm 4 upwardly whereby the locking device or plunger 5 moves to a position to lock a latching device (not shown) which normally secures the washing machine door. When all the water has been removed by spinning, the standing head collapses and air escapes through port 14 whereby the diaphragm 4 returns to its original position whereby the door can be unlatched. The time taken for air to leak through port 14 is selected such that the tub has either ceased rotating or has slowed to a safe speed. An alternative embodiment is shown in Fig 2 wherein like parts are identified by similar reference numerals. However, in this case, the controlled leak defined by port 14 and screw 15 is in the upper cupl 1 and the chamber 8 is directly closed by diaphragm 4. A non-return valve 17 is also provided in the cup 1 to allow air to escape from chamber 18 to permit the diaphragm 4 to move upwards to displace the plunger 5. The plunger 5 is supported in openings 19, 20 respectively provided in a recessed portion 21 and a support 22; a flexible annular seal 23 prevents air escaping from chamber 18. In the embodiment of Fig 2, valve 17 and the leak 14, 15 are isolated from the inlet to chamber 8 and therefore less susceptible to foreign matter. Operation is similar to the device described above except that air leaks from the atmosphere into chamber 18 when the standing head collapses. In both of the above described embodiments, the pressure inlet 16 may be connected via an air trap to a junction in the drain pipe of the washing machine or to the tub such that a static head of water is present in the trap whilst the tub contains water. This static head compresses air in the trap to maintain the diaphragm 4 in a position to cause the locking member 5 to lock the door latching device of the machine. The tub door cannot, therefore, be opened whilst it contains enough water to maintain the required air pressure. Under normal circumstances, this means that the tub door cannot be opened during a wash cycle. WHAT WE CLAIM IS:

1. A washing machine comprising a tub; t tub door; a latching device for said door; a lock for said latching device, said lock comprising a diaphragm which is moveable between first and second positions, said diaphragm being supported in a housing and dividing the housing into respective subchambers, a member connected to the diaphragm for locking said latching device when the diaphragm is in its second position and means for providing a controlled air leak for one of said subchambers whereby the diaphragm is restorable from its second to its first position over a predetermined period; the washing machine also comprising a drain pipe; a pump for removing water from the tub through said drain pipe whereby a head of water is provided in said pipe; an air trap connected to said pipe; and means connecting said air trap to one of said subchambers whereby said head of water in the drain pipe compresses the air in said air trap to cause the diaphragm to move from its first to its second position.

1 of the accompanying drawings.