GB2118266A

GB2118266A - Door lock control means in a front-loading washing machine

Info

Publication number: GB2118266A
Application number: GB08302912A
Authority: GB
Inventors: Georg Kirmes; Manfred Blank
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-04-06
Filing date: 1983-02-03
Publication date: 1983-10-26
Also published as: FR2524510B1; FR2524510A1; DE3212887C2; IT1161813B; GB8302912D0; IT8320397A0; GB2118266B; DE3212887A1

Abstract

In a circuit arrangement for the program control equipment of a front-loading washing machine with an electrically switchable barrier (VM) locking the loading door, the barrier (VM) is switchable to voltage (U) through a switching path (PS) of the program control equipment and that a water level transmitter (P) responds above a minimum liquor level in the region of the lower edge of the loading opening to switch a line (L1), which bridges over the switching path (PS), to be conductive. <IMAGE>

Description

SPECIFICATION Door lock control means in a front-loading washing machine The present invention relates to a front-loading washing machine provided with control means for an electrically actuable door lock of the machine.

In order to prevent the loading door of a front-loading drum washing machine from being opened when the liquor level in the drum is higher than the lower edge of the opening, it is known (DE-GM 19 09 31 1) to sense the liquor level by means of a pressure-measuring cell and to employ the diaphragm movement thereof directly or through lever gears for the locking of a door-opening key or of the door catch itself.

Mechanical door locks of that kind involve a high degree of production and assembly labour, are subject to substantial wear in operation and require considerable operating forces.

As proper closure of the door is in any case to be monitored in the case of use of electrical program control equipment, in order to exclude the spinning run when the door is opened, and as electrical switching paths are required for the Ivel-dependent switching-on of the electrical heating, additional mechanical complication for the level-dependent door locking would be uneconomical.

It would thus be of advantage to overcome the difficulties entailed by mechanical door locks and to provide a circuit arrangement in which, with utilization of existing switching paths for the monitoring of the door lock and for the level control, the loading door is generally prevented from being opened in the case of a liquor level above its lower edge.

According to the present invention there is provided a front-loading washing machine provided with control means for controlling an electrically securable door lock of the machine, the control means comprising first conductor means connected to a programme control switch of the machine to conduct current for actuation of the door lock, second conductor means to conduct current for securing the door lock independently of any current conducted by the first conductor means, and a level sensor so responsive to the wash liquor level in the machine exceeding a predetermined level in the region of the lowermost edge portion of a loading opening of the machine as to cause the second conductor means to become conductive.

In a preferred embodiment, the level sensor or water level transmitter signals a liquor level which lies somewhat above the lower edge of the loading opening and in the case of this level switches a line to be conductive which at the end of the program bridges over the internal switching path, which switches off the voltage supply, of the program control equipment. The electrically switchable locking barrier, which is connected to the internal voltage supply, therefore remains actuated by voltage in the case of high liquor level when the program control equipment has completely worked through a program and switched the internal voltage supply off at the end.

Embodiments of the present invention will now be more particularly described by way of example with reference to the accompanying drawings, in which: Figure 1 is a circuit diagram of first door lock control means embodying the invention; Figure 2 is a circuit diagram of second door lock control means embodying the invention; and Figure 3 is a circuit diagram of third door lock control means embodying the invention.

Referring now to the drawings, there is shown in each of Figs. 1 to 3 door lock control means in a front-loading washing machine, wherein mains voltage U passes through a program switch PS to an internal voltage supply L2, into which a door switch TS is connected for monitoring correct door closure. The door switch in the case of a properly closed door is so actuated by the door catch F that the internal line L2 is conductive. In the Fig. 1 embodiment, the switching state is illustrated with the program control equipment switched off. In that case, the program switch PS lies at an off-contact KO. With the door opened, the door switch TS is also open and a level switch NS of a water level transmitter P has the illustrated position in the case of a water level below the lower edge of the machine loading opening (not shown).

A locking magnet VM of a door lock TV is connected to the internal line L2 and receives voltage as soon as the program switch PS touches an on-contact K1 and the door switch TS switches the internal line L2 to be conductive with the door closed. The locking magnet VM pushes its bolt V into the notch of the door catch F so that the door can no longer be opened.

If, due to a fault, the liquor pump (not shown) of the machine has not pumped away liquor in the machine above the lower edge of the loading opening, even though the program control equipment has completely worked through the program and the program switch PS has switched over to the off-contact KO, the line L2 would, without the switch NS and line L1, now be free of voltage and the locking magnet VM could withdraw its bolt V and thereby unlock the door catch F. The operator would then be able to open the door and the liquor above the lower edge of the opening would freely flow out of the washing machine.

In the case of the circuit arrangement of Fig. 1, however, the switch NS of the water level transmitter P has switched the line L1, which bridges over the open program switch PS signalling the end of the program, to be conductive so that the mains voltage U is now conducted through the line L1 and the switch NS to the internal line L2 even after the end of the program. in the case of a high liquor level, the locking magnet VM therefore cannot withdraw its bolt V, so that the loading door remains locked.

In the circuit according to Fig. 1, the level switch NS is only limitedly unsable for other functions. In Fig. 2, a circuit arrangement is shown in which the switch NS can be employed for other functions within the program control equipment when these functions can be blocked off through program contacts in the basic setting, comprising the off-position, of the program control equipment. In the circuit according to Fig. 2, the connection of the line L1 bridging over with the off-contact KO of the program switch is here constructed as a program change switch PSW. The offcontact KO shown in Fig. 1 does not have to be present, so that the embodiment of Fig. 2, compared with that of Fig. 1, represents only a slight increase in effort, for example that involved in insertion of a further contact into an electro-mechanical program control device.

Such a contact is, however, only an inexpensive article which hardly contributes to an increase in cost. In the case of electronic circuit arrangements, functions of that kind are in any case present so that their utililzation does not represent an increase in effort.

The embodiment illustrated in Fig. 3, as in Fig. 2, shows the circuit in operative setting.

Compared with the embodiment of Fig. 2, it contains an additional overflow protection which is possible through a further contact KM for the motor M of the liquor pump. In the case of increase of the liquor level beyond a predetermined safety level, the water level transmitter P switches its switch NS to the contact KM so that the pump motor M lies at voltage and the liquor is pumped away until the switch NS is switched away from the contact KM. In this case, the switch NS-can be equipped with a drag contact SK, which, in the case of the contact KM being closed, also connects the switch NS with the contact KL for the bridging-over line L1, so that the door locking is secured in this switch setting in case the program change switch PSW should coincidentally connect the off-contact KO with voltage U.

In the illustrated circuit arrangements, an integrated door locking can also be employed, in which the door switch TS closes only after the door has been closed in the proper manner and the locked magnet VM is excited.

Claims

1. A front-loading washing machine provided with control means for controlling an electrically securable door lock of the machine, the control means comprising first conductor means connected to a programme control switch of the machine to conduct current for actuation of the door lock, second conductor means to conduct current for securing the door lock independently of any currnt conducted by the first conductor means, and a level sensor so responsive to the wash liquor level in the machine exceeding a predetermined level in the region of the lowermost edge portion of a loading opening of the machine as to cause the second conductor means to become conductive.

2. A washing machine as claimed in claim 1, wherein the first conductor means and the second conductor means are each connected to a respective one of two alternately selectable outputs of the control switch.

3. A washing machine as claimed in either claim 1 or claim 2, comprising a door switch operable in response to closure of the door to permit conduction of current to the door lock by one of the first conductor means and the second conductor means.

4. A washing machine as claimed in claim 3, wherein the door switch is arranged in series with the level sensor.

5. A washing machine provided with door lock control means substantially as herein be fore described with reference to any one of Figs. 1 to 3 of the accompanying drawings.