Overlifting door latch with locking mechanism

Abstract

A door latch for an electrical domestic appliance includes a rotary member rotationally movable in a rotation plane between a closing rotational position and a release rotational position, a movably arranged catch for arresting engagement by an overlifting rotational movement of the rotary member with the rotary member in its closing rotational position, and a locking assembly having a locking member movable between an unlocking position and a locking position. The rotary member is spring-biased towards the release rotational position and which, in the closing rotational position, holds a closure member to keep a door closed and, in the release rotational position, releases the closure member in order for the door to open. The locking member forms a first blocking arrangement by means of which the locking member in its locking position blocks the rotary member against rotation out of the closing rotational position into the release rotational position.

Claims

1. A door latch for an electrical domestic appliance, the door latch comprising: a rotary member which is arranged to be rotationally movable in a rotation plane between a closing rotational position and a release rotational position wherein the rotary member is spring-biased in the direction towards the release rotational position and which, in the closing rotational position, holds a closure member in order to keep a door of the domestic appliance closed and, in the release rotational position, releases the closure member in order for the door to open; a movably arranged catch for arresting engagement, which is releasable by an overlifting rotational movement of the rotary member, with the rotary member in its closing rotational position; and a locking assembly having a locking member, which is arranged to be movable between an unlocking position and a locking position, for blocking at least one movable component of the door latch when the door is closed, wherein the locking member in its locking position blocks the rotary member against rotation out of the closing rotational position into the release rotational position and in the unlocking position permits such rotation of the rotary member.

2. The door latch according to claim 1, wherein the locking member forms a first blocking arrangement which, in the locking position of the locking member, can be clamped between the rotary member and an abutment structure, in a clamping rotational position of the rotary member lying between the closing rotational position and the release rotational position, wherein the clamping of the first blocking arrangement is releasable by a rotational movement of the rotary member out of the clamping rotational position in the direction towards the closing rotational position.

3. The door latch according to claim 2, wherein the rotation angle between the clamping rotational position and the closing rotational position of the rotary member is smaller than the rotation angle between the clamping rotational position and the release rotational position of the rotary member.

4. The door latch according to claim 3, wherein the rotary member is smaller by a multiple of the rotation angle between the clamping rotational position and the release rotational position of the rotary member.

5. The door latch according to claim 2, wherein the rotation angle between the clamping rotational position and the closing rotational position of the rotary member is not more than 15 degrees.

6. The door latch according to claim 2, wherein the rotation angle between the clamping rotational position and the closing rotational position of the rotary member is not more than 10 degrees.

7. The door latch according to claim 2, wherein the rotation angle between the clamping rotational position and the closing rotational position of the rotary member is not more than 5 degrees.

8. The door latch according to claim 2, wherein the rotary member holds the closure member in order to keep the door closed also in its clamping rotational position.

9. The door latch according to claim 2, wherein the locking member is subjected or can be subjected in the locking position to the action of a spring bias which biases the locking member in the direction towards its unlocking position.

10. The door latch according to claim 9, wherein the locking assembly comprises a locking actuator having a positioning element whose position can be adjusted by activation of the locking actuator, wherein the locking member can be transferred against a restoring spring force out of the unlocking position into the locking position by means of a carrier coupling with the positioning element and, when uncoupled from the positioning element, can be returned.

11. The door latch according to claim 10, wherein the locking actuator is an electromagnetic actuator.

12. The door latch according to claim 2, wherein the abutment structure is formed on a housing component of a housing of the door latch which accommodates the rotary member, the catch and the locking assembly.

13. The door latch according to claim 1, wherein the locking member is arranged to be movable transversely to the rotation plane of the rotary member at least in an end portion of its movement path that includes the locking position.

14. The door latch according to claim 1, wherein the locking member is arranged to be movable perpendicularly to the rotation plane of the rotary member at least in an end portion of its movement path that includes the locking position.

15. The door latch according to claim 1, wherein the locking member is in the form of a locking slider which is arranged to be linearly movable in a sliding direction perpendicular to the rotation plane of the rotary member.

16. The door latch according to claim 1, wherein the locking member forms a second blocking arrangement which blocks the catch in at least one movement direction in the locking position of the locking member.

17. The door latch according to claim 1, comprising a carrier component for the rotary member which is arranged to be displaceable against spring force out of a rest position into an emergency opening position, wherein, upon displacement of the carrier component out of the rest position into the emergency opening position, the catch can be lifted out of arresting engagement with the rotary member by striking a stop arrangement, wherein the stop arrangement is formed on the locking member and is moved in the locking position of the locking member out of a standby position, in which the stop arrangement is ready for striking by the catch.

18. The door latch according to claim 1, comprising a carrier component for the rotary member which is arranged to be displaceable pivotally against spring force out of a rest position into an emergency opening position, wherein, upon displacement of the carrier component out of the rest position into the emergency opening position, the catch can be lifted out of arresting engagement with the rotary member by striking a stop arrangement, wherein the stop arrangement is formed on the locking member and is moved in the locking position of the locking member out of a standby position, in which the stop arrangement is ready for striking by the catch.

19. The door latch according to claim 1, comprising an opening assembly having an opening actuator and an actuating element, movable by activation of the opening actuator, for acting on the catch in order to lift it out of arresting engagement with the rotary member.

20. The door latch according to claim 19, wherein the opening actuator is an electromagnetic actuator.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG. 1 is a perspective view of a door latch according to an embodiment in an open state.

[0026] FIG. 2 is a top view of the door latch of FIG. 1, wherein a locking module of the latch has been removed.

[0027] FIG. 3 is a top view of the door latch of FIG. 1, wherein a housing cover of the locking module has been removed.

[0028] FIG. 4 is a sectional view of the door latch of FIG. 1 in the open state.

[0029] FIG. 5 is a top view of the door latch of FIG. 1 similar to FIG. 3 but in a closed and locked state.

[0030] FIG. 6 is a sectional view of the door latch in the state according to FIG. 5.

[0031] FIG. 7 is a sectional view of the door latch of FIG. 1 in a state upon opening of the latch by means of an opening assembly.

DETAILED DESCRIPTION OF THE INVENTION

[0032] The door latch generally designated 10 in the figures has a multi-part latch housing 12 in which a carrier lever 14, a locking slider 16 (see in particular FIG. 2), a locking module 18 and an opening unit 20 are accommodated as the main components. A rotary member 22 and a catch 24 which is pivotable in at least two movement directions are additionally mounted on the carrier lever 14. In the region of one of its lever ends, the carrier lever 14 is mounted on the latch housing 12 to be pivotable about a pivot axis 26. The rotary member 22 is mounted on the carrier lever 14 to be rotatable about a rotation axis 28 which is parallel to the pivot axis 26 and stationary relative to the carrier lever 14. By means of a pair of spring elements (here: helical compression springs) 30 (see FIGS. 4, 6 and 7) arranged axially on either side of the rotary member 22, the carrier lever 14 is biased into a rest position, from which it can be pivoted, for the purposes of emergency opening, about the pivot axis 26 against the force of the spring element 30 into an emergency opening position.

[0033] The door latch 10 is provided for fitting into a domestic washing machine, for example, whereby the latch housing 12 is to be fixed, for example, to a machine wall of a machine main body of the washing machine, in which a washing vessel (drum or barrel) is rotatably mounted. A closure member 32 (see FIG. 6) is attached to a door, which is pivotably mounted on the machine main body and serves to close an access opening to the washing vessel, which closure member enters an insertion opening 34 formed in the latch housing 12 when the door is closed and cooperates with the rotary member 22, which can be also be referred to as a gripper. It will be appreciated that a reverse assembly pattern can be chosen as an alternative, that is to say the closure member 32 can be mounted on the machine main body and the latch housing 12 with the components accommodated therein can be fixed to the door.

[0034] When the door is open, the rotary member 22 assumes a release rotational position which can be seen in FIG. 4, in which it is ready for a transverse stirrup 36 of the closure member 32 to enter a gripping mouth 42, delimited by two jaws 38, 40, of the rotary member 22. As the door closes, the closure member 32 first comes into contact with its transverse stirrup 36 with the jaw 40 and thereby initiates a rotation of the rotary member 22 about the rotation axis 28 against the force of a biasing spring 44, which is formed in the example shown by a leg spring and which biases the rotary member 22 into the release rotational position. As the rotary member 22 rotates, the jaw 38 moves behind the transverse stirrup 36 of the closure member 32. As soon as the rotary member 22 reaches a closing rotational position shown in FIG. 6, the catch 24 engages by means of a nose 46 behind an arresting edge 48 formed on the outer periphery of the rotary member 22 and thus prevents the rotary member 22 from rotating back in the direction towards the release rotary position. The transverse stirrup 36 of the closure member 32 is in this state caught in the gripping jaw 42 of the rotary member 22; the door is closed. This situation is shown in FIG. 6 (the rotary member 22 additionally being shown locked in FIG. 6).

[0035] The arresting edge 48 is part of a sliding guide which is formed on the outer periphery of the rotary member 22 and which allows the door latch 10 to be opened by an overlift (renewed pushing against the door of the washing machine from outside). If, starting from the closed but unlocked state of the door latch 10, the user pushes against the door, this causes the rotary member 22 to rotate beyond the closing rotational position (overlifting rotational movement). The sliding guide is in such a form that, in the case of such an overlifting rotational movement of the rotary member 22, the nose 46 of the catch 24 springs away from the arresting edge 48 sideways, under the action of a biasing spring 50 acting on the catch 24. The biasing spring 50 thereby urges the nose 46 of the catch 24 onto a portion of the sliding guide that does not offer any possibility of arresting the rotary member 22. If the user then removes the pressure from the door, the rotary member 22 therefore rotates under the action of its biasing spring 44 back in the direction towards the release rotational position. Because the nose 46 of the catch 24 thereby no longer has an arresting hold on the rotary member 22, the rotary member 22 rotates beyond the closing rotational position into the release rotational position according to FIG. 4. For further details of the sliding guide formed on the outer periphery of the rotary member 22, reference is made by way of example to DE 39 19 458 A1, in particular to the explanations given therein in relation to FIGS. 3 to 5 of the mentioned document.

[0036] The locking slider 16 forms a locking member within the meaning of the invention and is linearly displaceable in the embodiment shown in a sliding direction 52 parallel to the rotation axis 28 of the rotary member 22 (that is to say perpendicular to the rotation plane of the rotary member 22) (see FIG. 2). The locking module 18 serves to control the movement of the locking slider 16 and forms a structural unit which can be pre-assembled and inserted as such into the latch housing 12. The locking module 18 comprises a module housing 54 having a housing bottom part 56 and a housing cover 58, which has been removed in the views of FIGS. 3 and 5. The locking module contains an electromagnetic actuator 60 having a magnetic coil, of which only a coil body 62 is shown in FIGS. 3 and 5, and further having an armature plunger 64 which can be pulled into the magnetic coil by excitation thereof, and a positioning element 66 which is coupled with the armature plunger 64 for transmitting pull and push.

[0037] In the example shown, the positioning element 66 is in the form of a pivotably mounted positioning lever which is pivotable by excitation of the magnetic coil and consequently by movement of the armature plunger 64. The positioning lever 66 is adjustable by successive pulse-like excitations of the magnetic coil alternately into two different pivot positions, which correspond to an unlocking position or locking position of the locking slider 16. In FIG. 3, the positioning lever 66 assumes one of these defined pivot positions, and in FIG. 5 it assumes the other pivot position. For the stable adjustment of the positioning lever 66 into the two pivot positions, there is provided in the example shown a sliding guide having a path follower which is formed by a wire stirrup 68 and revolves endlessly in a sliding guide path, which is not shown in greater detail in the figures. Such sliding guides are generally known; a more detailed explanation is not required at this point. Of course, the electromagnetic actuator 60 is not the only possibility for moving the positioning lever 66or a positioning element generallybetween two stable positions corresponding to the unlocking position and the locking position of the locking slider 16. For example, an electromotive drive unit can be provided as an alternative.

[0038] In the embodiment shown, the locking slider 16 is provided only for transferring from the unlocking position into the locking position in a carrier coupling (here: push-type coupling) with the positioning lever 66. The return movement of the locking slider 16 out of the locking position into the unlocking position takes place only under the force of a biasing spring 70 (see FIG. 2), which biases the locking slider 16 into its unlocking position. When the door latch 10 is locked, that is to say when the positioning lever 66 is transferred out of the pivot position according to FIG. 3 into the pivot position according to FIG. 5, the positioning lever 66 pushes the locking slider 66 against the force of the biasing spring 70 out of the unlocking position into the locking position (on the right in the representation of FIG. 3). As a result, a spring bias which can be used for the return of the locking slider 16 builds up in the biasing spring 70 or an already existing spring bias is increased. The biasing spring 70 acts as a mechanical energy store, which is charged, as it were, when the latch 10 is locked. When the positioning lever 66 pivots out of the pivot position according to FIG. 5 into the pivot position according to FIG. 3, on the other hand, there is no longer a carrier coupling between the positioning lever 66 and the locking slider 16. In this movement direction there is neither a pushing- or a pulling-force-transmitting coupling between the positioning lever 66 and the locking slider 16. If the locking slider 16 is not blocked in the case of an unlocking actuation of the electromagnetic actuator 60, the locking slider 16 follows the movement of the positioning lever 66 on account of the spring tension of the biasing spring 70 and moves back into its unlocking position. However, if the locking slider 16 is blocked in its locking position (see below), only the positioning lever 66 moves back, whereas the locking slider 16 remains in its locking position until its blocking is eliminated. The mechanical energy store formed by the biasing spring 70 thus permits a return of the locking slider 16 from the locking position into the unlocking position that is decoupled from the positioning lever 66 in terms of time and mechanically.

[0039] In order to lock the door latch 10 in the closed state, the locking slider 16 is formed with a first blocking arrangement 72 (see in particular FIG. 6), which in the locking position of the locking slider 16 has moved into the rotation path of the rotary member 22 and thereby prevents the rotary member 22 from rotating back out of the closing rotational position according to FIG. 6 into the release rotational position according to FIG. 4. Specifically, the first blocking arrangement 72, when the locking slider 16 is transferred from the unlocking position into the locking position, moves into the rotation path of the jaw 38 of the rotary member 22, which in the closed state engages behind the transverse stirrup 36 of the closure member 32. In the unlocked state, on the other hand, the first blocking arrangement 72 has moved out of the rotation path of the jaw 38 and does not constitute an obstacle to the rotation of the rotary member 22 out of the closing rotational position back into the release rotational position.

[0040] It has been mentioned that, in the locked state of the door latch 10, blocking of the locking slider 16 can occur, which prevents the locking slider 16 from automatically returning from the locking position into the unlocking position. Such blocking of the locking slider 16 can occur when, in the locked state, the nose 46 of the catch 24 slips away from the arresting edge 48 of the rotary member 22, for example as a result of vibrations, and therefore the catch 24 loses the arresting engagement with the rotary member 22. After the loss of the arresting of the rotary member 22 by the catch 24, the rotary member 22 attempts to rotate, under the action of its biasing spring 44, out of the closing rotational position in the direction towards the release rotational position. After a certain, comparatively small rotation angle of, for example, a few degrees, it meets the first blocking arrangement 72 (clamping rotational position of the rotary member 22). The force of the biasing spring 44 then leads to clamping of the first blocking arrangement 72 between the rotary member 22 and an abutment structure formed by the latch housing 12, which abutment structure is formed in the example shown by a base plate 74 of the latch housing 12 and a supporting rib 76 formed on the base plate 74. Clamping of the first blocking arrangement 72 of the locking slider 16 occurs in any case after such a small rotation angle of the rotary member 22 that the closure member 32 remains caught in the gripping jaw 42 of the rotary member 22, that is to say the door remains closed. Even after an unlocking activation of the electromagnetic actuator 60 and pivoting of the positioning lever 66 back into the pivot position according to FIG. 3, the clamping of the locking slider 16 initially persists and the door remains closed. Only when the user then again pushes against the door and initiates an overlifting rotational movement of the rotary member 22 is the clamping of the locking slider 16 released, whereupon the biasing spring 70 urges the locking slider 16 back into its unlocking position. If the user then releases the door, the rotary member 22 is free to rotate back into the release rotational position according to FIG. 4, because the first blocking arrangement 72 no longer blocks the rotary member 22 against rotation.

[0041] There is further formed on the locking slider 16 a second blocking arrangement 78, which serves to block the catch 24 against lateral pivoting in the case of an overlifting opening attempt. In the locked state, the second blocking arrangement 78 prevents lateral pivoting of the catch 24, by means of which the nose 46 would pivot onto such a portion of the sliding guide of the rotary member 22 on which the catch 24 can no longer arrest the rotary member 22 in its closing rotational position. If, in the locked state of the door latch 10, the user pushes against the door, this leads to an overlifting rotational movement of the rotary member 22 but, because the catch 24 is blocked against lateral pivoting by the second blocking arrangement 78, the nose 46 of the catch 24 comes into arresting engagement with the arresting edge 48 of the rotary member 22 again when the user removes the pressure against the door. In the unlocked state of the door latch 10, on the other hand, the second blocking arrangement 78 is out of range of the catch 24 and does not stand in the way of lateral pivoting thereof, as is required for a normal overlifting opening operation.

[0042] In addition, there is formed on the locking slider 16 a stop arrangement 80 which serves as a stop for a tongue 82 formed on the catch 24 in the case of emergency opening of the door latch 10. When the door is closed but still unlocked, the stop arrangement 80 is in an active position beneath the tongue 82 of the catch 24. If in this situation the door is pushed from inside the washing vessel of the washing machine (emergency opening), the carrier lever 14 is pivoted out of the rest position against the force of the spring elements 30. The rotary member 22 held on the carrier lever 14 moves with the carrier lever 14 as it pivots. Because the catch 24 is biased by the biasing spring 50 in engagement with the outer periphery of the rotary member 22, the catch 24 also moves until the tongue 82 meets the stop arrangement 80. With continued pivoting of the carrier lever 14, the catch 24 is lifted out of arresting engagement with the rotary member 22 as a result of the tongue 82 striking the stop arrangement 80, so that the rotary member 22 is able to rotate out of the closing rotational position back into the release rotational position and the door latch 10 is opened. In the locking position of the locking slider 16, on the other hand, the stop arrangement 80 is out of range of the tongue 82, so that the emergency opening function of the door latch 10 is not available in the locked state.

[0043] In addition to the possibility of opening the door latch 10 by overlifting (renewed pushing against the door from outside) and in addition to the possibility of emergency opening by pushing against the door from inside which is provided by the pivotability of the carrier lever 14, a third opening possibility is given in the case of the door latch 10 according to the embodiment shown, for the purpose of which the opening unit 20 is accommodated in the latch housing 12. The opening unit 20 permits controlled opening of the door latch 10 by means of an electrical control signal, which can be generated automatically by a control unit of the washing machine at the end or with a time delay after the end of a wash program. Alternatively or in addition, such a control signal can be generated by a user if he presses on a corresponding operating button of the washing machine. In the example shown, the opening unit 20 comprises a second electromagnetic actuator 86, separate from the electromagnetic actuator 60, having a magnetic coil 88 and an armature plunger 90 which cooperates with a control lever 94 pivotably mounted on the latch housing 12 about a pivot axis 92. The control lever 94 is biased into an out-of-engagement position by a biasing spring 96. In FIGS. 1 to 6, the control lever 94 is shown in this out-of-engagement position. By feeding current to the magnetic coil 88, a movement of the armature plunger 90 into the magnetic coil 88 can be effected. The armature plunger 90 thereby initiates pivoting of the control lever 94 about the pivot axis 92 against the force of the biasing spring 96 and urges the control lever 94 into an engagement position shown in FIG. 7. When the control lever 94 is pivoted out of the out-of-engagement position into the engagement position, the control lever 94 presses against an end of the catch 24 that is remote from the nose 46 and thereby lifts the catch 24 out of engagement with the outer periphery of the rotary member 22. The rotary member 22 is thus free to rotate out of the closing rotational position back into the release position. This situation is shown in FIG. 7 (for reasons of clarity, the closure member 32 is not shown in FIG. 7).

[0044] Although the preferred embodiments of the present invention have been described herein, the above description is merely illustrative. Further modification of the invention herein disclosed will occur to those skilled in the respective arts and all such modifications are deemed to be within the scope of the invention as defined by the appended claims.