Door locking and unlocking device for a pyrolytically cleaned cooking oven.

p0001Disclosed is a device for locking and unlocking door for cooking enclosure, particularly for an enclosure of pyrolytic cleaning cooking.

p0002It is requested by current regulations to equip pyrolytic cleaning oven with an automatic locking-unlocking system of the door above a certain temperature to prevent opening of the door during operation in pyrolysis.

p0003Different types of locking and unlocking are offered, latches devices controlled by solenoid as in FR 73 13 831 and FR 73 01 363; locking arm devices driven by electric motor and controlled by micro-switches such as that shown in Figure 1 and which is used by the applicant for its reference constructor 800 of ovens.

p0004This device consists of a motor (M), two micro-switches (MC1) and (MC2), a lever (L), a lock (V), a spring (R).

p0005As soon as the oven control main switch is turned on pyrolysis position, the motor (M) is switched on and drives the lever (L) in rotation to release the lock (V) which, under the action of the spring (R ) descends and locks the door.

p0006The lock (V) down releases the micro-switch (MC1) while allowing the initiation of the heating for the cleaning cycle, and in its rotation, the lever (L) based on the micro-switch (MC2) stopping and the motor.

p0007By placing the main switch to a position other than pyrolysis, the motor is powered again, but then rotates in the opposite direction. The lever (L) in its rotation: - Back the lock (V) which releases the door, - Based on the micro-contact (MC1): the engine loses power.

p0008But the engine can be operated only if the thermostat has switched pyrolysis, that is to say that the temperature in the chamber is lower than the temperature required by the regulations.

p0009This device thus has two moving parts, the lever (L) and the lock (V), each of which controls a microswitch, and requiring two non-integral guide means.

p0010The major disadvantages of the device are of requiring large gaps construction, yet amplified by the lever length (L), to act on the microswitches by two separate moving parts, and to actuate the micro switch (MC2) and the lock (V) by two separate lever arms (L) thereby separating the two commands. These games are, in a number of cases, the cause of malfunction, for example a total door lock or unlock at the end of pyrolysis immediately followed by a new locking.

p0011To overcome this problem one solution would be to add to the current mechanical control device for electromagnetic relays.

p0012This solution would however be costly.

p0013To overcome all the disadvantages of the prior art, the applicant has totally change the preferred mechanical device.

p0014To achieve its goal, the applicant has established in order both micro switches via a single finger integral with the lock, and to gather all the guidance and positioning functions on a single medium, to reduce Games.

p0015All these conditions are satisfied by the preferred embodiment without limiting the invention which is described below.

p0016According to the invention, the locking device and oven door unlocking comprises a synchronous motor, a movable bolt carrying a catch, a return spring, two microcontacts and is characterized in that it further comprises on the one hand a single support carrying the synchronous motor and the lock, and at least one lateral guide means secured to said carriage lock, on the other hand a single transmission arm integral with one end of the motor shaft synchronous and comprising at its other end an attachment means for the return spring, and a latch driving element capable of producing a straight vertical movement of the latch, for example a cam.

p0017Furthermore, the lock has a single finger adapted to actuate in turn the two microswitches tongues, placed in the same plane. In the case where the associated electrical circuit would require more than two micro-switches, may be provided if necessary a plurality of fingers.

p0018The invention will be better understood using the following description with reference to the following appended figures:<ul><li>- Figure 1: Overview of the locking-unlocking device of the prior art.</li><li>- Figure 2: overview of a preferred embodiment without limiting the present invention.</li><li>- Figure 3: side view of the device of Figure 2 in mounting position on the frame of the cooking chamber with closed door.</li><li>- Figure 4: front view of Figure 3 with the door open.</li></ul>

p0019The preferred non-limiting embodiment shown in the attached figures is mainly composed of: - Two micro switches (1, 2) - A spring (3), - A transmission arm (4), - A bolt (5) movable, - A latch (6) integral with the lock (5), - A motor reducer (7), - A bar (8), - A support (20).

p0020The support (20) is designed both to support the set of all the elements constituting the locking-unlocking device, and to perform all the guidance functions of all moving parts of the same device.

p0021The support (20) is formed from a stamped and bent metal plate. We distinguish a central plate (26) bearing a vertical stamped (28), said central plate is extended on the one hand at the top by an upper lug (21) and a horizontal edge (22) obtained by vertically folding, on the other hand in the upper part also a side tab (27) horizontally and perpendicular to the central plate (26) and secondly in the lower part of a lower leg (24) horizontally and perpendicular to the central plate (26 ), and an edge (23) parallel to the vertical central plate (26), the tab (24) and the rim (23) being obtained by folding the tab (24) having a means for guiding the latch (6 ), for example a light (25), vertical, rectangular, having guide constrictions (32) adjusted to the thickness of the latch, for example and not limited to two in number, arranged opposite one another.

p0022The main functions of the different parts of the support (20) just listed are not limited to: - Mounting and positioning of the entire device on the frame of the oven by any appropriate means, for example as in the figures by screwing or riveting the borders (22), (23) on the uprights (9a) (9b) of the frame (9). - Supporting microswitches (1) and (2) so that the opening positions and control of closure tabs are in the same vertical plane parallel to the bolt displacement direction. - Motor bracket (7) which is fixed by any appropriate means (29) in the upper part of the central plate (26), preferably, for reasons of space on the other side of said plate (26) relative to arm (4) and latch (5).

p0023The support has other functions described below.

p0024Moreover, the latch is a metal rod flat substantially L-shaped and having at its lower end a latch (6) guided vertically and laterally by the light (25) and the throttles (32) at its upper two straps one end it ( 10a, 10b) and a finger (11) side obtained by cutting and folding.

p0025In addition the transmission arm (4) is secured to one end of the motor shaft (7) and has at the other of its ends a fastening means (4a) for the spring (3), and next to the lock cam (4b) capable of converting the circular movement of the arm (4) into a rectilinear movement of the latch (5) (see Figure 2).

p0026The spring is a standard spring hooked on the one hand (4a), on the other hand to one or the other of the fasteners (10a, 10b) of the latch (5) according to the selected voltage. May optionally provide for a greater number of fasteners.

p0027The support (20) is completed by a web (8) with ensuring the central plate (26) of the support the side guides of the bolt (5), respectively lateral enclosure side guide and lateral outer side.

p0028For example the strip is secured to the support (20) by two bushes (30) blocked by screws (31) or by any other appropriate means. There is provided a set of bosses (33), for example four in number on the stamping (28) and four on the web (8), to ensure good sliding of the bolt (5) (see Figure 4), and arranged in pairs opposite each other. The sockets (30) constitute fixed points of the set (support (20), web (8)) which cooperate with the oblong slots (13) provided in the bolt (5) to allow its displacement. The slots (13) extend parallel to the axis of displacement latch (5) and their length is appropriate to the magnitude of slip of said lock.

p0029The device operates as follows:

p0030Once the enclosure control switch, not shown, is placed on pyrolysis position, the motor (7) turns on and drives the arm (4), and under the action of the spring latch (5) passes in the lower position as shown in dotted lines in Figure 3. the latch (6) goes down and locks the door, then the finger (11) presses the micro switch tongue (2) which cuts power to the motor (7) .

p0031Simultaneously, the micro-switch tongue (1) has been released and the cleaning cycle begins.

p0032By placing the handle of the switch to a position other than pyrolysis, the motor is powered again (if the enclosure temperature is below the temperature required by the regula tions), but running in the opposite direction of the previous case. In this case, through the lever (4) and the cam (4b) the latch (5) passes in the raised position and releases the door, and then the finger (11) presses the micro switch tongue (1 ) to cut power to the motor.

p0033According to the invention, the latch (5) controls via a single finger (11) the two micro-switches, the movement of said latch being controlled by the single lever (4) together with the spring (3) .

p0034The two micro-switches being controlled by the same finger (11) is removed, relative to the prior art device, the clearance between the arm (L) and the lock (V), also reduces the play of lock the tilting in a vertical plane parallel to the support. Further up the play of vertical slip of the lock is ensured by the spring (3) constantly pulling in the same direction.

p0035The invention is not limited to the embodiment shown and described above but covers all the variants include variants of shapes and sizes of component parts.