EP1828686B1 - Door lock for an oven - Google Patents

Abstract

The oven door (2) has a recess (8) for the latch (6) hook (7) which is a locked position due to a projection (14) on the motor shaft (9) raising the other end (22) of the latch lever. Rotation of the shaft releases the latch lever end to raise the latch hook by means of a torsion spring (26). To accommodate a height variation (R) in the door the latch lever pivot arms reside in vertically slotted holes in the holding bracket (23).

Description

The invention relates to a locking device for the door of a baking oven, in particular an oven with pyrolytic self-cleaning. Such a door lock is for example from the DE 197 05 821 C1 and from the US 4,927,996 known.

In the pyrolytic self-cleaning of ovens, temperatures in the range of 500 ° C and higher occur. Due to this temperature stress, it is easy to warp components of the cooker. This can result in its door not being reliably locked during pyrolytic cleaning of the cooker. Regardless of safety aspects, only a limited functionality of a locking device of a cooker can also lead to unnecessary heat loss. The functionality of a locking device can also be affected by production-related tolerances.

The invention has for its object to provide a locking device for the door of a baking oven, in particular a pyrolysis stove, which is characterized by particular robustness and tolerance insensitivity.

This object is achieved by a door lock with the features of claim 1. This door lock has an electric motor drive, a drivable thereby switching shaft, and an actuatable by this locking element. As a locking element, a lever is provided, the lever axis relative to the locking housing reversible spatially displaceable, in particular against spring force, is. Characterized in that the lever which locks the door of the oven, not only about its lever axis pivotally, but also in total, including the lever axis, is mounted in the housing of the door lock, is always a perfect locking function. This is especially true in cases where components of the cooker warp by heat. The lever of the locking device thus has at least two degrees of freedom, namely a degree of freedom relating to the pivoting movement and an additional degree of freedom, in particular a translational movement concerning.

After a structurally particularly simple embodiment, the lever is mounted in a slot. Instead of storage by means of a slot, the lever axis can be displaced in a linear or along a certain path in any other way. The slot or the other guidance of the lever axis is preferably designed such that upon a force from the door of the cooker in the opening direction on the lever, that is at an attempted opening of the locked door, the lever axis is drawn within the slot in a defined direction , The slot has for this purpose relative to the axis of the switching shaft an inclined position of less than 90 °, for example 60 ° to 85 ° on. The axis of the switching shaft indicates at least approximately the direction in which a force is exerted on the door and thus on the locking device in the attempted opening of the hearth. The switching shaft and the lever operated by this are in this embodiment approximately at right angles to the plane in which the stove door is located.

The lever of the locking device can be acted upon by spring force in a defined manner to occupy a certain angular position and a specific axis position. In a preferred embodiment, both functions, i. the exercise of a force acting in the direction of a certain angular position, namely the open position of the lever, and the exercise of a force acting on the lever axis towards a defined end position within the elongated hole, realized by a single spring. The spring tries to always position the lever axis so that the lever can engage at most in a provided for the locking counterpart of the door of the stove.

A particularly space-saving construction of the locking device can be achieved by the lever extends substantially parallel to the axis of the switching shaft. In particular, in the closed, ie the door of the stove locking state of the lever closes with the axis of the switching shaft only a small angle, for example, less than 10 °, in particular less than 5 °, a. In the open state of the lever, however, this is more pronounced with respect to the axis of the switching shaft tilted, for example, at an angle of up to 30 °. The lever axis is arranged transversely to the axis of the switching shaft in this case.

The switching shaft has in a preferred embodiment in addition to the contouring, which is provided for actuating the lever, for example in the form of one or more switching cam, at least one further actuating contour, which switches an electrical locking contact system. Furthermore, the door lock preferably comprises a door contact system which is mechanically independent of the position of the switching shaft and of the lever and which detects the position of the door of the cooker. This door contact system works in a compact design preferably with an operable from the door of the stove slide, which is arranged parallel to the switching shaft (and thus also substantially parallel to the lever) in the locking housing.

The lever of the door lock is mounted on a holding plate, which is displaceable in the locking housing, in particular in the axial direction of the switching shaft. In this context, a holding plate is understood to mean, irrespective of the geometric design, any part on or in which the axis of the lever, that is to say of the locking element, is mounted. The lever axis may be fixed or movable relative to the retaining plate, in particular slidable in a slot guide. In the last-mentioned, preferred case, the lever axis thus has a plurality of linearly independent translation options. The lever thus has a total of three degrees of freedom, namely the pivoting about the lever axis, the displaceability of the lever axis in the slot and the displaceability of the holding plate including the slot.

With the help of the storage of the lever on or in the sliding plate several functions, even in combination, can be fulfilled, namely in particular an emergency unlocking function and a closing function. The emergency unlocking function allows, once the force of a spring has been overcome, the opening of the lever, which was previously brought by means of the switching shaft in the locking position, without actuation of the switching shaft. In the process of emergency unlocking, ie the violent opening of the oven door despite the switching shaft being in the locked position, the holding plate is displaced by the pulling force on the lever so far in the axial direction of the switching shaft, that the lever no longer contacts the actuating contour of the switching shaft, but slides over a front end of a switching cam or a switching disc, and thus opens by spring force and / or by the force acting on the door by pulling on the door. Preferably, however, the lever is not completely pulled away from the shift shaft during emergency unlocking, but only so far that the open lever still contacted a portion of the shift shaft with a reduced diameter. Also in this reduced diameter range, the switching shaft on an eccentric or a functionally comparable contour, which makes it possible to bring the lever by rotation of the switching shaft by means of the electric motor back into the locking position.

In the described interaction of the lever with the shift shaft during emergency unlocking and later re-locking is preferably not only the lever axis transversely to the extent thereof displaced but also the shift shaft slidably, namely in the axial direction. The holding plate, which serves to support the lever, as well as the switching shaft are acted upon in the opposite direction with spring force, wherein the spring force acting on the holding plate exceeds the force acting on the switching shaft spring force. As a result, as soon as the lever has been released by emergency unlocking, the selector shaft will move in the direction away from the lever, i. towards the electric motor, suspended. This axial displacement of the shift shaft can be used to trigger an electrical switching operation, which indicates the opening of the lever.

The displaceability of the holding plate of the lever in the axial direction of the switching shaft, ie, substantially in the direction in which a force is to be exerted on the door to close it, also allows the integration of a closing function in the door lock in a particularly simple manner. In this case acts on the retaining plate permanently a force through which the retaining plate is displaced so that the door is tightened by means of the hooked into this lever. The cooperating with the lever switching contour of the switching shaft is designed such that the closing function only comes into force when the lever is already completely in the locked position. As long as the lever is still fully or partially open, that is, has not yet completely intervened in the corresponding locking contour of the door, the closing function by a switching contour, such as an eccentric element, the switching shaft, on which remains the lever is applied, blocked. Only after completion of the pivoting movement of the lever, the longitudinal movement of the lever, that is, the displacement in the axial direction of the switching shaft, released by suitable design of the switching contour and thus activates the closing function upon further rotation of the switching shaft. During subsequent motorized opening of the lever after completion of the pyrolytic self-cleaning, the lever is first moved in the reverse order through the switching shaft in the axial direction of the switching shaft and then pivoted into the open position.

Fig. 1

in einer Explosionsdarstellung eine Türverriegelung für einen Herd,

Fig. 2

eine Draufsicht auf die Türverriegelung nach Fig. 1 in offenem, unverrie- geltem Zustand,

Fig. 3

in ausschnittsweiser, geschnittener Seitenansicht die Vorrichtung nach Fig. 2 in offenem Zustand,

Fig. 4

in einer Darstellung analog Fig. 3 die Türverriegelung und eine Herdtüre in geschlossenem, verriegeltem Zustand,

Fig. 5

in einer Darstellung analog Fig. 2 die Türverriegelung in geschlossenem, verriegeltem Zustand,

Fig. 6 und 7

jeweils eine Exzenterwelle einer Türverriegelung nach den Fig. 1 bis 5 beziehungsweise nach den Fig. 10 bis 14,

Fig. 8 und 9

in Darstellungen analog Fig. 3 und 4 die Türverriegelung nach den Fig. 1 bis 5 während des Vorgangs der Notentriegelung,

Fig. 10

in einer Explosionsdarstellung analog Fig. 1 ein zweites Ausführungsbei- spiel einer Türverriegelung,

Fig. 11

in einer ausschnittsweisen, geschnittenen Seitenansicht die Türverriege- lung nach Fig. 10 und eine Herdtüre,

Fig. 12

eine Draufsicht auf die Anordnung nach Fig. 11,

Fig. 13

in einer Darstellung analog Fig. 11 die Herdtüre und die Türverriegelung mit aktivierter Zuziehfunktion, und

Fig. 14

eine Draufsicht auf die Anordnung nach Fig. 13.

An embodiment of the invention will be explained in more detail with reference to a drawing. Herein show:

Fig. 1

in an exploded view, a door lock for a stove,

Fig. 2

a plan view of the door lock after Fig. 1 in open, unlocked condition,

Fig. 3

in a sectional, sectional side view of the device Fig. 2 in open condition,

Fig. 4

in a representation analog Fig. 3 the door lock and a stove door in closed, locked state,

Fig. 5

in a representation analog Fig. 2 the door lock in closed, locked state,

6 and 7

each an eccentric shaft of a door lock after the Fig. 1 to 5 or after the 10 to 14 .

8 and 9

in representations analog 3 and 4 the door lock after the Fig. 1 to 5 during the emergency release procedure,

Fig. 10

in an exploded view analog Fig. 1 A second embodiment of a door lock,

Fig. 11

in a partial, sectional side view of the door lock according to Fig. 10 and a stove door,

Fig. 12

a plan view of the arrangement according to Fig. 11 .

Fig. 13

in a representation analog Fig. 11 the oven door and the door lock with activated closing function, and

Fig. 14

a plan view of the arrangement according to Fig. 13 ,

Corresponding or equivalent parts are provided in all figures with the same reference numerals.

The Fig. 1 to 5 1 shows a first exemplary embodiment of a door lock 1 for a pyrolysis stove, of which only one hearth door 2 (see FIG. Fig. 4 ) is visible. The door lock 1 is installed in the stove in a horizontal position and has a lock housing 3 with a housing lower part 4 and a housing cover 5. From the housing 3 protrudes as a locking element 6, a lever out, which is also substantially in horizontal mounting position and can engage with a hook 7 in a locking contour 8 of the oven door 2.

For actuating the lever 6, ie for locking the oven door 2, a switching shaft 9 is provided, which by a geared motor 10 at a speed of about 10 U / min. is drivable. The geared motor 10 is fixed by means of a retaining spring 11 on the lock housing 3 and has a horizontally arranged shaft, in the extension of which the shift shaft 9 is located. The shift shaft 9, also referred to as eccentric shaft, in Fig. 6 shown in more detail, serves on the one hand the operation of the lever 6 and on the other hand, the actuation of locking contacts 12,13, which form an electrical locking contact system. For actuating the lever 6, the switching shaft 9 an eccentric screw 14, which merges into a cam 15. The locking contact system 12,13 is actuated by a projection 16 on the shift shaft 9.

If the lever 6 is closed by turning the eccentric screw 14 and thus locks the oven door 2, the locking contact system 12,13 is closed by the approach 16 at the same time and thus generates an electrical signal indicating the locking of the oven door 2. Only when this electrical signal is applied, the pyrolytic self-cleaning process is started in the stove. Prerequisite for the described motorized locking of the oven door 2 is that it is completely closed. To detect this, a slider 17 is provided, which is arranged substantially parallel to the lever 6 and is pushed into the lock housing 3 when the hearth door 2 is closed. In this case, door contacts 18, 19 are opened by a switching contour 20 of the slide 17. A force that the slider 17 off the Verriegeiungsgehäuse 3 out, so presses in the direction of the oven door 2, is exercised by a spring 21. Deviating from the illustrated embodiment, the door contact system formed by the door contacts 18,19 could also be designed such that when closing the oven door 2, a closing of the door contacts 18,19. Likewise, closing and opening functions could also be interchanged with the locking contacts 12, 13. For the electrical connection of the electric motor 10 with the transmission, motor connections 37 are located inside the locking housing 3.

As in particular from Fig. 4 shows the locking member 6 in the locked state only a small angle, namely an angle of less than 5 °, with the axis A of the shift shaft 9 a. The locking element 6 is thus arranged substantially perpendicular to the oven door 2. For mounting of the locking element 6, which is designed as a two-armed lever, at one end of the hook 7 and at the other end is a cooperating with the switching shaft 9 actuating contour 22, a holding plate 23 is provided. The holding plate 23 is made as a bent sheet metal part and has two lateral legs 24, in each of which a slot guide 25 is formed. The lever 6 is partially disposed between the legs 24, wherein the lever axis H is in the slot guides 25. In the embodiment, the slot guides 25 are one-sided, namely upwards, open; but could also be used on both sides closed slot guides for storage of the lever 6.

In order to press the lever axis H in the direction of an end position, namely the end portion facing the housing lower part 4, within the slot guides 25, a spring 26 in the form of a double leg spring is provided. This spring 26 also serves to the lever 6 in the direction of its open position ( Fig. 3 ). Together with the slot guides 25, the spring 26 further allows a tolerance compensation, with the particular different positions of the oven door 2 relative to the door latch 1, for example, triggered by thermal stresses or assembly inaccuracies can be intercepted. When locking the oven door 2 should, as in Fig. 4 illustrated, the hook 7 of the locking element 6, if possible, the entire depth T of the locking contour 8 exploit. If the oven door 2 in the vertical direction R, perpendicular to the axis A of the shift shaft 9, adjusted upward, it could, if the lever axis H of the locking element 6 would be stationary, the shift shaft 9 are no longer completely brought into locking position, ie in that position, in which the cam 23 tilts the lever 6 as far as possible about the lever axis H. This would mean that the locking contact system 12,13 can not close and thus no signal is given that the oven door 2 is locked and the pyrolytic cleaning process can be started. In the case of a stationary lever axis H, therefore, in order to rule out such a malfunction, the door lock 1 would have to be mounted with a vertical distance to the oven door 2 which is too large in itself. However, this in turn would have the disadvantage that the hook 7 of the locking element 6 does not fully engage in the locking contour 8.

In order to prevent the above-mentioned malfunctions and disadvantages, as shown in FIG Fig. 4 recognizable, the lever axis H are moved within the slot guides 25 in a direction of displacement V. By the given lever mechanism, the lever axis H shifts within the slot guides 25 only slightly for larger changes in the positioning of the oven door 2 relative to the locking housing 3. The function of the switching shaft 9 is not dependent on where the lever axis H is disposed within the slot guides 25. The displacement direction V includes with the axis A an angle of slightly less than 90 °, for example an angle of 65 ° to 85 °, a. If in the locked state of the oven door 2 at this with a force F whose direction corresponds to the position of the axis A pulled so is prevented by the inclination of the slot guides 25 that the lever axis H of the locking element 6 within the slot guides 25 toward whose open ends shifted.

Is pulled with too much force F on the stove door 2, that is trying to open them forcibly, but still a destruction of the door latch 1 should be avoided. For this purpose, the holding plate 23 in the axial direction, that is, in the direction of the axis A, slidably mounted in the locking housing 3. An angled leaf spring 27, which is clamped on the one hand to a side wall 28 of the housing base 4 and on the other hand rests against a front strip 29 of the holding plate 23, pushes it in the axial direction A of the switching shaft 9 away from a front wall 30 of the housing base 4, that is, in the direction of the gear motor 10. In normal operation of the door lock 1, that is, as long as the emergency unlocking function is not used, the support plate 23 is pressed against a stop in the lock housing 3 in the same position. The emergency release only comes into operation when pulling on the stove door 2 with forces that far exceed the minimum locking forces.

The function of the emergency release will be described below with reference to 8 and 9 explained. The greater the force F with which is pulled on the oven door 2, the more the holding plate 23 is displaced against the force of the leaf spring 27 in the direction of the front wall 30 of the lock housing 3. Finally, as in Fig. 9 illustrated, the actuating contour 22 of the lever 6 is no longer engaged with the eccentric screw 14 or the cam 15 of the shift shaft 9, so that the lever 6 by the force F, supported by the action of the spring 26 opens. As soon as the lever 6 has opened by way of emergency unlocking, the actuating contour 22 of the lever 6 engages on an end face 31 of the switching shaft 9.

The shift shaft 9 is as well as the support plate 23 longitudinally displaceable, ie displaceable in the direction of the axis A, stored in the lock housing 3. A compression spring 32 loads the shift shaft 9 and counteracts the leaf spring 27, but is designed much weaker than this. When the emergency release of the locking element 6 is therefore, as soon as the lever 6 in the open position ( Fig. 9 ) works, the leaf spring 27 at least partially relaxed again and compresses the compression spring 32. The displacement of the switching shaft 9 in the direction of the gear motor 10 causes the projection 16 is moved so far that the locking contact system 12,13 opens. Thus, the control of the door lock 1 receives a signal that the locking of the lever 6 is canceled, although the angular position of the shift shaft 9 still corresponds to the locking position. After the violent opening of the oven door 2, by rotation of the switching shaft 9, driven by the geared motor 10, again in Fig. 8 shown positioning of the movable parts are set 6.9, wherein the compression spring 32 expands again and thus shifts the shift shaft 9 in the axial direction to the locking element 6, as soon as the locking contour 8 is no longer in engagement with the end face 31 of the shift shaft 9. Overall, this is an emergency release the door lock 1 without damaging any components and thus given an effective overload protection.

Another embodiment of a door lock 1 for an oven, in particular a stove, which is suitable for pyrolytic self-cleaning, is in the 10 to 14 shown. The holding plate 23 is additionally loaded in this case by the force of a compression spring 33 which, like the leaf spring 27 exerts a force in the direction of the selector shaft 9, but is designed to be weaker. As long as the lever 6 is open, the compression spring 33 is largely compressed, that is, the holding plate 23 moved close to the front wall 30 of the locking housing 3. In this position of the holding plate 23, the hook 7 engage approximately centrally in the locking contour 8 of the oven door 2, as in Fig. 11 shown. As long as the lever 6 is tilted by the switching shaft 9, the axial position of the holding plate 23 does not change or only insignificantly.

An eccentric 14 ', also referred to as an eccentric screw, the shift shaft 9 of the door lock 1 after the 10 to 14 is how in Fig. 7 shown, compared to in Fig. 6 illustrated switching shaft 9 of the embodiment according to the Fig. 1 to 5 modified and in particular has the function not only to control the tilting movement of the lever 6 but also its movement in the direction of the axis A. As soon as the lever 6 has reached its maximum deflection in the direction of the locking position, the actuating contour 22 of the lever 6 arrives in an opening section 34 on the eccentric screw 14 '. In this area, the lever 6 remains in the locking position and simultaneously moves axially to the rear, ie in the direction of the geared motor 10. In this process, the compression spring 33 expands, as in Fig. 13 represented, so that the hook 7 comes to rest on a side surface 35 of the locking contour 8 and the hearth door 2 with a pulling force Z attracts. The compression spring 33 exerts a lower force than the pressure shaft 32, which always loads the control shaft 9. When unlocking the lever 6, first, the holding plate 23 is axially displaced in the reverse direction. For this purpose, the eccentric screw 14 'on an inclined surface 36, by means of which the compression spring 33 is compressed until about the in Fig. 11 shown position of the lever 6 is reached before this is opened.

LIST OF REFERENCE NUMBERS

1

door lock

2

oven door

3

lock housing

4

Housing bottom

5

housing cover

6

Locking element, lever

7

hook

8th

locking profile

9

shift shaft

10

gearmotor

11

retaining spring

12

interlock

13

interlock

14.14 '

eccentric screw

15

cam

16

approach

17

pusher

18

door contact

19

door contact

20

switching contour

21

feather

22

actuating contour

23

Retaining plate

24

leg

25

Slot guide

26

feather

27

leaf spring

28

Side wall

29

front bar

30

front wall

31

face

32

compression spring

33

compression spring

34

opening section

35

side surface

36

sloping surface

37

motor connection

A

axis

F

force

H

lever axis

R

direction

T

depth

V

displacement direction

Z

traction

Claims (13)

1. Door lock for an oven, comprising a geared motor (10), an actuating shaft (9) which can be driven by said geared motor, and a locking element, which can be operated by the actuating shaft (9), in the form of a lever (6) whose lever axle (H) can be moved in a reversible manner in relation to a lock housing (3),

   - the lever (6) being mounted on a retaining plate (23), and characterized

   - in that, in an emergency-unlocking function when the force of a spring (27) is overcome, the retaining plate (23) can be moved in such a way that it is possible to open the lever (6) which was previously moved to the locking position by means of the actuating shaft (9), without further operation of the actuating shaft (9), and

   - in that the actuating shaft (9) can be moved along its axis (A) by the lever (6) which has been unlocked in an emergency.
2. Door lock according to Claim 1, characterized in that the lever (6) is mounted in a slotted guide (25).
3. Door lock according to Claim 2, characterized in that the slotted guide (25) is inclined in relation to the axis (A) of the actuating shaft (9).
4. Door lock according to Claim 2 or 3, characterized in that the lever (6) is loaded by a spring (26) which exerts a force both on the lever axle (H) in the direction of an end position within the slotted guide (25) and on the lever (6) in the direction of its open position.
5. Door lock according to one of Claims 1 to 4, characterized in that the lever axle (H) is arranged transverse to the axis (A) of the actuating shaft (9).
6. Door lock according to Claim 5, characterized in that the lever (6) extends substantially parallel to the axis (A) of the actuating shaft (9).
7. Door lock according to one of Claims 1 to 6, characterized by an electrical locking contact system (12, 13) which can be operated by the actuating shaft (9).
8. Door lock according to one of Claims 1 to 7, characterized by a door contact system (18, 19) which is mechanically independent of the position of the actuating shaft (9) and of the lever (6).
9. Door lock according to Claim 8, characterized in that a slide (17) of the door contact system (18, 19) is arranged parallel to the actuating shaft (9) in the lock housing (3).
10. Door lock according to one of Claims 1 to 9, characterized in that the retaining plate (23) can be moved along the axis (A) of the actuating shaft (9) in the lock housing (3).
11. Door lock according to one of Claims 1 to 10, characterized in that the actuating shaft (9) has a contact element (16) which can be operated by the emergency unlocking of the lever (6) and is intended to trigger an electrical actuating operation.
12. Door lock according to one of Claims 1 to 11, characterized in that an eccentric element (14') of the actuating shaft (9) which interacts with the lever (6) is formed in such a way that, in the locked state of the lever (6), the retaining plate (23) can be displaced in the direction of the actuating shaft (9) by spring force.
13. Door lock according to Claim 12, characterized in that the eccentric element (14') of the actuating shaft (9) is formed in such a way that, when the lever (6) is unlocked, the retaining plate is first moved in the axial direction of the actuating shaft (9) and the lever (6) is then pivoted upward.

Images