GB2346926A

GB2346926A - A door lock with means to reduce force required to open the door

Info

Publication number: GB2346926A
Application number: GB9924851A
Authority: GB
Inventors: Albert Dirnberger
Original assignee: ZANGENSTEIN ELEKTRO
Current assignee: ZANGENSTEIN ELEKTRO
Priority date: 1998-10-20
Filing date: 1999-10-20
Publication date: 2000-08-23
Anticipated expiration: 2019-10-20
Also published as: GB9924851D0; ITTO990907A0; DE19848275A1; ITTO990907A1; DE19848275C2; GB2346926B; IT1311238B1

Abstract

A device tor locking a door of a domestic appliance which has an elastic seal (not shown); the device comprising a closure dog or door hook 16 and a locking body 12. The locking body 12 can be moved between on open position, a closed position in which the seal of the door is strongly compressed and a relaxed position in which the sea is less strongly compressed but the door remains closed. The relaxed position allows the door to be opened by a reduced force than that required to open the door from the closed position directly. The locking body 12 moves from the closed position (figure 2) to the relaxed position (figure 3) by pivoting the locking body 12 about end stop 24. This is facilitated by opener 14 sliding to the right as shown in the figures so that locking body 12 moves from a resting shoulder 46 of opener 14 to another resting shoulder 50. Locking body 12 may be slid linearly to an open position by electromagnet 30 (figure 4). Switch 40 prevents the appliance from operating except when the locking body 12 is in the closed position.

Description

2346926 Device for locking a door of a domestic appliance

The invention relates to a device for locking 5 a door of a domestic appliance, having the features of the preamble of Patent Claim 1.

The invention can be used in general for all types of domestic appliances. In the following text, the invention is to be explained, by way of example, on the basis of washing machines.

Various types of so-called "magnetic door locks" are known from the prior art.

DE 35 27 670 C2 discloses a door lock in which a rigid closure dog on the door butts against a rotary bolt and presses it inwards counter to the force of a spring. In the process, a locking pin which is arranged on the rotary bolt engages in a window in the closure dog. As soon as the rotary bolt has reached a certain position, a locking slide which is preloaded by a spring engages behind a projection on the rotary bolt and blocks it from rotating in the opening direction. The door is thus held in the closed position. To open the door, the locking slide is removed from the rotary bolt by means of an electromagnet. The door, which is preloaded in the opening direction by the door seal and the spring of the rotary bolt, then springs open immediately. The user provides the impulse for opening the door by actuating a door-opening button in the control panel of the machine. A drawback of this system is its substantial height in the area of the rotary bolt and also its complicated structure.

DE 196 01 228 Al discloses a magnetic door lock in which a locking body prevents a door hook from opening the door. Locking and unlocking positions of the locking body can be controlled by means of an element which is 2 preloaded in such a manner as to be bistable and a safety bolt. The bistable element moves the safety bolt in order to secure the locking body in a closed position and to release it in an open position. The safety bolt or the locking body is positively coupled to two switches, so that the various positions of the door lock can be checked by electric means. Nevertheless, this door lock has the drawback of having a very complicated structure and only being usable for hooks which are moveably attached to the door. Thus, the control must be effected by means of an electronic control unit, since there is no forced dependency on the switches.

The prior art also includes systems in which a slide is pulled out beneath a hook which is attached to the door. In the process, the hook pulls with all the tensile force of the compressed elastic seal on the locking slide, so that there is considerable friction between hook and locking slide and between locking slide and housing. These systems therefore have the drawback that very high levels of force are required for unlocking, and this in turn entails large and expensive actuating magnets.

DE-U 17 17 612 describes a lock for locking a watertight door with a rubber seal on a special machine.

The lock has a closure dog and a catch which can be moved into a closed position, in which the seal is strongly compressed. In the closed position, the catch is preloaded by a catch spring which is supported on a blocked support. To open the door, the blocking of the support can be eliminated in a simple manner, so that the catch is no longer supported and is suddenly pushed back by the seal, which is still strongly compressed. The catch is then in its open position and releases the door, which then suddenly springs open. Although this lock is easy to open, it has the drawback that the catch is I 3 retracted suddenly when the door is opened, coming to bear against the closure dog and being pressed strongly onto the latter by the seal. The catch is therefore subjected to high levels of wear. Furthermore, it is S unpleasant for a user of the special machine if the door springs open suddenly. Moreover, this lock is of substantial height in the area of the closure dog.

It is an object of the present invention to provide a door lock which is of simple structure, can be used for both a stationary and a moveable door hook, only requires slight unlocking force and is of only small structural size in the area of the closure dog or door hook.

A further object of the invention is to provide a simple door lock which detects manual pressure on the door, so that the actuating magnets are prevented from burning through. This allows such a lock to be used even in appliances with simple (mechanical) control.

Accordingly a first aspect of the invention proposes a device for locking a door of a domestic appliance, having an elastic seal, a closure dog or door hook, and a locking body, wherein the locking body can be moved into a closed position in which the seal is compressed and the closure dog or door hook is prevented from opening the door; wherein the locking body can be moved into a relaxed position in which the seal is less strongly compressed than in the closed position and the closure dog or door hook is still prevented from opening the door, and wherein the locking body can be moved into an open position in which the seal is initially also less strongly compressed than in the closed position and is then relieved of pressure because the closure dog or door hook is released for opening the door.

Such a movement of the locking body into a relaxed position and then into an open position reduces 4 the tensile stress which the compressed elastic seal exerts on the closure dog or door hook, so that the closure dog or door hook can be opened with a low unlocking force via the locking body, for example by means of a magnet. The device can be used for both moveable and stationary hooks.

Expediently, the movement of the locking body from the closed position into the relaxed position takes place in the direction of the movement of the closure dog or door hook when the door is being opened. The movement of the locking body from the relaxed position into the open position advantageously takes place transversely with respect to this direction. In such an arrangement, the tensile force which is generated on the closure dog or door hook by the compressed seal can be used to good effect to move the locking body when the pressure is being relieved.

Moreover, it is expedient for the locking body to be spring-preloaded into the closed position transversely with respect to the direction of movement of the closure dog or door hook when the door is being opened. It is thus possible for the locking body to be moved when the closure dog or door hook is being introduced and then, in the spring -preloaded position, to prevent the closure dog or door hook from opening the door.

It is particularly advantageous if the locking body can be moved from the closed position into the relaxed position by a pivoting movement and from the relaxed position into the open position by a linear displacement. The device can thus be realized in a particularly simple form and is of only a small height in the region of the locked hook.

A second aspect of the invention proposes a device for locking a door of a domestic appliance, having I I an elastic seal, a closure dog or door hook, and a locking body; wherein the locking body can be moved into a closed position in which the seal is compressed and in which the locking body prevents the closure dog or door hook f rom opening the door, and can be moved into an open position in which it releases the closure dog or door hook for opening the door, wherein that the locking body can be moved into a first knee-test position which differs from the open position and in which the door is closed and subject to manual pressure, the locking body being supported by the closure dog or door hook, and can be moved into a second knee-test position or at-rest position which differs from the closed position and in which the door is not closed, or is closed and is subject is to manual pressure, while the locking body is not under load from the closure dog or door hook.

In these so-called first and second knee-test positions, the closed door is subject to manual pressure, for example from the knee of a user of the washing machine. Although the locking body would release the door for opening, the door is therefore not opened. In known door locks, this may lead to an electromagnet which actuates the locking body being continuously excited and therefore burning through. Since the first and second knee-test positions of the locking body according to the invention differ from the closed position and the open position, these positions can be taken into account when exciting the electromagnet, making it possible to prevent the latter from burning out.

Preferably, the locking body can be moved from the second knee-test position or at-rest position into the closed position essentially in the direction of the closure dog or door hook when the door is being opened.

By contrast, the locking body can be moved from the second knee-test position or at-rest position into the 6 f irst knee-test position transversely with respect to this direction of movement. In such a device, the tensile force of a compressed seal which is acting on the closure dog or door hook and the movement of the closure dog or door hook can be used to particularly good effect when pressure is being exerted in the closed state of the door.

It is also advantageous for the locking body to be spring -pre loaded into the second knee-test position or at-rest position in the direction of movement of the closure dog or door hook. Then, in its at-rest position, the locking body always adopts a clear position and can be moved out of this position by means of the closure dog or door hook.

The structure of the device is particularly simple and compact if the locking body can be moved from the second knee-test position or at-rest position into the closed position by means of a pivoting movement and into the first knee-test position by means of a linear sliding movement.

In order to check the various positions of the locking body, it is advantageously proposed for the locking body to close a switch in the closed position, in the relaxed position and during a movement into the open position, while it opens a switch in the second knee-test position or at- rest position and in the first knee-test position. This switch is able to interrupt the actuation of the actuating element, i.e., for example, of an electromagnet, and/or the actuation of the domestic appliance as a whole. This ensures that the electromagnet does not burn out and that the domestic appliance cannot be operated if the door is not closed correctly.

The subject-matter of the invention may be of particularly simple design if the locking body is supported on a support bearing and, in the closed I 7 position, on a moveable shoulder. In this position, the locking body is then able to absorb high tensile forces from a closure dog or door hook.

This moveable shoulder can preferably be displaced by means of an actuating element, so that the locking body moves into the relaxed position by means of a pivoting movement. when the actuating element subsequently moves the locking body, so that the locking body adopts the open position, the device can be opened particularly easily and with little force, so that the actuating element only has to supply a small actuating force and can therefore be of particularly small design. In addition, the actuating element can cover a free travel between the movement of the shoulder and of the locking body, over which free travel it is able to take up additional kinetic energy.

The moveable shoulder is advantageously arranged in such a way that it is further from the support bearing than an engagement point of the closure dog or door hook on the locking body. In such an arrangement, the leverage principle means that a greater force acts on the engagement point of the closure dog or door hook than on the bearing point of the moveable shoulder. According to the laws of friction, the force component for moving the shoulder is proportional to the force component on the bearing point of the shoulder. The moveable shoulder can therefore be moved away from the locking body by means of a lesser force than that required to move the locking body itself away from the closure dog or door hook. Moreover, the surface on the bearing point of the moveable shoulder may be of a particular configuration, such that it has a particularly low coefficient of friction.

A preferred exemplary embodiment of the device according to the invention for locking a door of a 8 domestic appliance is explained in more detail below with reference to the appended diagrammatic figures, in which: Fig. 1 shows a side view, partially in longitudinal section, of a device according to the invention 5 for locking a door of a domestic appliance, which device is in an at- rest position; Fig. 2 shows the device illustrated in Fig. 1 in a closed position; Fig. 3 shows the device illustrated in Fig. 1 in a relaxed position; Fig. 4 shows the device illustrated in Fig. 1 in an open position; Fig. 5 shows the device illustrated in Fig. 1 in a first knee-test position 1; Fig. 6 shows the device illustrated in Fig. 1 in a second knee-test position 2.

Fig. 1 shows a device according to the invention, for locking a door of a domestic appliance.

This device is intended for use in a washing machine. The essential components of the device are a housing 10, a locking body 12, an opener 14 and a door hook 16.

The door hook 16 is attached to the washing machine door (not shown) and can be guided through an opening 18 in the housing 10 to the locking body 12. The door hook 16 may be either a moveable door hook or a stationary door hook.

The locking body 12 bears against a support bearing 20 on the housing 10 and is preloaded by a first spring 22 into the direction of movement of the door hook 30 when closing and transversely with respect to this direction of movement. The locking body 12 in this case bears against a first stop 24 and a second stop 26, which are both connected to the housing 10, so that the locking body 12 adopts an at-rest position.

The opener 14 is used to unlock the device and I 9 is actuated by means of a plunger 28 of an electromagnet 30. The plunger 28 is preloaded onto the opener 14 by a second spring 32, so that the opener 14 is pushed to the left, with respect to Fig. 1, and bears, by way of a first shoulder 34, against an edge 36 of the locking body 12.

Furthermore, a switch 38 with a switching plunger 40 is attached to the housing 10, which switching plunger is moved into a position which opens the switch 38 by the locking body 12 which is preloaded in its atrest position. Due to the open position of the switch, both the electromagnet 30 and the washing machine itself cannot be operated. Such operation is also impermissible for safety reasons, since the door and therefore the door hook 16 are not locked.

Fig. 2 shows the device in a closed position. The door hook 16 has been guided through the opening 18 to the locking body 12 and, in the process, has moved the locking body 12 to the right, with res pect to Fig. 1, so that a locking edge 42 of the locking body 12 comes to rest behind a projection 44 of the door hook 16. Due to the elastic seal which is arranged in the door and is not shown, a tensile stress acts on the door hook 16, pulling the projection 44 of the door hook 16 onto the locking body 12, in the opening direction of the door. This tensile stress is greater than the spring preloading from the first spring 22, which is diagrammatically depicted as a dashed line in Fig. 2. Therefore, the locking body 12 is moved towards the opener 14 by the door hook 16 and comes to bear against a second stop 46 on the opener 14.

Thus, in the closed position which has been adopted, the locking body 12 bears against the support bearing 20, against the first stop 24 and against the second shoulder 46 on the opener 14. Its right-hand end part 48 has moved downwards, with respect to Fig. 2, and in the process has released the switching plunger 40 of the switch 38. Thus the switch 38 is closed, allowing the washing machine to be actuated.

The edge 36 of the locking body 12 is further than the locking edge 42 from the support bearing 20. Due to the leverage principle, a lower perpendicular force component (i.e. a downwards component as seen in Fig. 2) acts on the second shoulder 46 of the opener 14 than the force component which the door hook 16 on the locking edge 42 exerts on the locking body 12. Therefore, the frictional force which has to be overcome on the second shoulder 46 is also lower than on the projection 44 of the door hook 16.

Fig. 3 shows the device in the relaxed position. To adopt this relaxed position, the locking body 12 is moved to the right, with respect to Fig. 2, by means of the opener 14. This iseffected by means of the plunger 28 of the electromagnet 30. The plunger 28 works in the opposite direction to the second spring 32, and its right-hand end 281 strikes a third stop 50 on the opener 14, which it then moves. However, the right-hand end 28, of the plunger 28, in the positions mentioned above, does not bear against the third stop 50, but rather initially covers an empty travel, during which it is able to take up kinetic energy. Consequently, the actuating electromagnet can be of particularly small design.

When the opener 14 is being displaced, the locking body 12 is held in its left-hand position, with respect to Fig. 3, owing to the first spring 22 and the relatively high frictional force in the area of the projection 44 on the door hook 16. The second shoulder 46 of the opener 14 therefore moves to the right, in relation to the edge 36 of the locking body 12, and the edge 36 slides over the second shoulder 46. Since the I i elastic seal exerts a tensile stress on the door hook 16, the door hook 16, via the projection 44, pulls the locking body 12 into the relaxed position illustrated in Fig. 3. In the process, the locking edge 42 of the locking body 12 has moved relative to the housing 10, in the opening direction of the door hook 16, and has therefore relieved the pressure on the seal (not shown). The switch 38 is likewise not activated in the relaxed position, since the door cannot yet be opened.

Fig. 4 shows an open position of the device. In order to transfer the locking body 12 from the relaxed position into this position, the plunger 28 of the electromagnet 30 moves the opener 14 further to the right, with respect to Fig. 4. This is effected by a fourth stop 52 of the opener 14, after an empty travel, coming into contact behind a second edge 54 of the locking body 12 and moving the locking body 12 along with it when the opener 14 moves. During the empty travel, the opener 14 gathers kinetic energy, so that more energy is available to move the locking body than without an empty travel. The locking body 12 moves away from the first stop 24, so that its locking edge 42 releases the projection 44 of the door hook 16.

Fig. 4 shows precisely the position in which the door hook 16 is released. In this position, the seal is initially likewise less strongly compressed than in the closed position. Since the door hook 16 has been released, the pressure on the seal can then be relieved further, with the effect that the door hook 16 moves out of the opening 18 and the door opens.

During the movement of the locking body 12 as far as the open position, the switching plunger 40 of the switch 38 is not actuated. However, after the locking edge 42 has released the door hook 16, the locking body 3S 12 is moved upwards, with respect to Fig. 4, by the first 12 spring 22, so that its right-hand end part 48 actuates the switching plunger 40. The switch 38 is thus opened and detects that the door has been opened.

Fig. 5 shows the device in a first knee-test position 1. In such a knee test 1, the door of the washing machine is prevented from opening from the outside. This may, for example, result from the knee of a user bearing against the door. The electromagnet 30 seeks to unlock the door and has therefore moved the opener 14 to the right by means of the plunger 28. In the process, the locking edge 42 of the locking body 12 has been moved to the right, past the locking edge 42 of the door hook 16, and the door hook 16 has for the time being been released. However, the pressure on the door does not allow the pressure on the seal to be relieved. The door does not open and the door hook 16 remains in the opening 18. The locking body 12 is preloaded upwards by the first spring 22. When the door hook is released, the locking body is pulled upwards and bears against the support bearing 20. It actuates the switching plunger 40, with the result that the switch 38 is opened and the supply of current to the electromagnet 30 is interrupted. The electromagnet cannot burn through.

In the first knee-test position 1, the projection 44 of the door hook 16 bears against the locking edge 42 of the locking body 12. The locking body 12 adopts a stable position. As soon as the door of the washing machine is no longer subjected to manual pressure from the outside, the door hook 16 moves out of the opening 18, since the pressure on the elastic seal of the door is relieved. The locking body 12 then adopts its atrest position due to the preloading of the first spring 22.

Fig. 6 shows the device in a second knee-test position 2. In such a position, the door hook 16 has been I 13 pushed into the opening 18 by manual pressure on the door sufficiently far for the locking body 12 to again be able to adopt its at-rest position without being subjected to tensile load from the door hook 16. Therefore, the projection 44 of the door hook 16 does not bear against the locking body 12. The overall position of the device corresponds to the at-rest position illustrated in Fig. 1, except for the fact that the door hook 16 has been pushed into the opening 18.

In this second knee-test position 2, the right- hand end part 48 of the locking body 12 again actuates the switching plunger 40 of the switch 38. The switch 38 interrupts any actuation of the electromagnet 30, so that the door cannot be unlocked. The switch 38 is only closed again when the user ends the manual pressure on the door, so that the device moves into the closed position illustrated in Fig. 2. From this position, the door can be unlocked again by means of the electromagnet 30 and then opened. In this way, not only is the magnet prevented from burning through but reliable locking and unlocking of the door of the washing machine is also ensured.

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Claims

1. A device for locking a door of a domestic appliance, having an elastic seal, a closure dog or door hook, and a locking body, wherein the locking body can be moved into a closed position in which the seal is compressed and the closure dog or door hook is prevented from opening the door; wherein the locking body can be moved into a relaxed position in which the seal is less strongly compressed than in the closed position and the closure dog or door hook is still prevented from opening the door, and wherein the locking body can be moved into an open position in which the seal is initially also less strongly compressed than in the closed position and is then relieved of pressure because the closure dog or door hook is released for opening the door.

2. A device according to Claim 1, wherein the locking body can be moved from the closed position into the relaxed position essentially in the direction of movement of the closure dog or door hook.

3. A device according to Claim 1 or 2, wherein the locking body can be moved from the relaxed position into the open position essentially transversely with respect to the direction of movement of the closure dog or door hook.

4. A device according to any one of Claims 1 to 3, wherein the locking body is spring-preloaded into the closed position transversely with respect to the direction of movement of the closure dog or door hook.

5. A device according to any one of Claims 1 to 4, wherein the locking body can be moved from the closed position into the relaxed position in a rotary manner in the direction of movement of the closure dog or door hook and can be moved from the relaxed position into the open position in a translational manner transversely I with respect to the direction of movement of the closure dog or door hook.

6. A device according to any one of Claims 1 to 5, wherein the locking body closes a switch in the closed position, and in the relaxed position and while it is moving into the open position.

7. A device for locking a door of a domestic appliance, having an elastic seal, a closure dog or door hook, and a locking body; wherein the locking body can be moved into a closed position in which the seal is compressed and in which the locking body prevents the closure dog or door hook from opening the door, and can be moved into an open position in which it releases the closure dog or door hook for opening the door, wherein that the locking body can be moved into a first knee-test position, which differs from the open position and in which the door is closed and subJect to manual pressure, the locking body being supported by the closure dog or door hook, and can be moved into a second knee-test position or at-rest position which differs from the closed position and in which the door is not closed, or is closed and is subject to manual pressure, while the locking body is not under load f rom the closure dog or door hook.

8. A device according to Claim 7, wherein the locking body can be moved from the second knee-test position or at-rest position into the closed position essentially in the direction of movement of the closure dog or door hook.

9. A device according to Claim 7 or 8, wherein the locking body can be moved from the second knee-test position or at-rest position into the first knee-test position essentially transversely with respect to the direction of movement of the closure dog or door hook.

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10. A device according to any one of Claims 7 to 9, wherein the locking body is spring-preloaded into the second knee-test position or at-rest position in the direction of movement of the closure dog or door hook.

11. A device according to any one of Claims 7 to 10, wherein the locking body can be moved from the second knee-test position or at-rest position into the closed position in a rotary manner in the direction of movement of the closure dog or door hook and into the first knee-test position in a translational manner, transversely with respect to the direction of movement of the closure dog or door hook.

12. A device according to any one of Claims 7 to 11, wherein the locking body opens, a switch in the is second knee-test position or at-rest position and in the first knee- test position.

13. A device according to Claim 6 or claim 12, wherein the switch interrupts the actuation of the actuating element and/or the actuation of the domestic appliance.

14. A device according to any one of the preceding claims, wherein that the locking body is supported on a support bearing and, in the closed position, on a moveable shoulder.

15. A device according to Claim 14, wherein the moveable shoulder and the locking body can be displaced by means of an actuating element.

16. A device according to Claim 15, wherein the actuating element can be used to move firstly the moveable shoulder and then the locking body, with the effect that after it has moved the moveable shoulder it covers a free travel before it moves the locking body, so that it takes up kinetic energy.

17. A Device according to any one of Claims 14 to 16, wherein the moveable shoulder is further from the I 17 support bearing than an engagement point of the closure dog or door hook on the locking body.

18. A device according to any one of claims 1 to 17, when fitted on a washing machine. 5

19. A device for locking the door of a domestic appliance, such device being constructed and adapted to operate substantially as hereinbefore with reference to, and as illustrated in, the accompanying drawings.