Patent Grant
9084526
This application claims priority to German Patent Application No. DE 10 2010 016 918.8, filed on May 12, 2010 and European Patent Application No. EP 10 401 128.3, filed on Aug. 3, 2010, both of which are hereby incorporated by reference herein in their entireties.
The present invention relates to an automatic warewashing machine with a door that can be held in the closed position by a force-locking or force- and form-locking latching mechanism.
In automatic warewashing machines having a force-locking or force- and form-locking door lock which is disposed on the washing chamber side and may also be referred to as “pull-type release lock”, it is desirable to provide a unit which allows the door to be automatically opened by a few centimeters, either by the automatic warewashing machine in a cycle-dependent manner or by the user. Cycle-dependent opening is generally performed shortly before the end of the cycle to assist in the drying process. An automatic door opening system should always be made available to the user when there is no handle that would allow the user to pull the door open. This is the case, for example, in handle-free, fully integratable appliances.
A dishwasher having an automatic door-opening system is described, for example, in DE 10 2005 028 449 A1. In this appliance, the latching mechanism is mounted on the door and adapted to engage with a latch keeper secured on the washing chamber. In order to allow the door to be automatically opened to an ajar position in a program-controlled manner, the latch keeper is mounted to a closing plate which is movable by a motor. Upon receipt of a signal from the appliance controller, the motor extends the closing plate, and thus the latch keeper. In this manner, the door is opened to an ajar position, but kept in a latched state. In order to open the door, a handle is pulled up, thereby rotating a latching member to a position where it is no longer held by the latch keeper.
In document WO 2009/146 874 A1, too, the latch keeper mounted on the washing chamber is moved by a driving mechanism to open the door to an ajar position. Here, the driving mechanism is implemented as a spring which is tensioned as the door is opened further.
The aforementioned automatic door opening devices can only be used in automatic warewashing machines where the latching mechanism is mounted in the door and the latch keeper is disposed on the washing chamber or housing of the machine. This results in disadvantages.
For example, displays or controls cannot be mounted in the middle of the door, and the space actually available for such components is limited. It is necessary to use printed circuit boards which have cutouts for the latching mechanism and, therefore, are expensive to manufacture. In addition, in the case of door-mounted latching mechanisms, the door must have a cutout, which may lead to ingress of moisture and damage to the electronics.
U.S. Pat. No. 4,951,693 also describes a dishwasher having an automatic opening system. Here, a spring mechanism becomes loaded as the door is closed, and the door is latched in the closed position. Upon release of the latch by a solenoid, the spring mechanism automatically opens the door. Additional springs hold the door in a partially open position.
A spring mechanism for opening the door to an ajar position is also used in a dishwasher as described in EP 2 210 547 A1, where a pull-type release lock is used as the latching mechanism.
During operation, the washing chamber of automatic warewashing machines should be closed liquid-tight. To this end, the access opening of the washing chamber is surrounded by a seal against which the door presses. The latching mechanism must be capable of counteracting the force with which the seal presses against the door in the opening direction. If the latching mechanism is suddenly released, such as in U.S. Pat. No. 4,951,693 A, or is overcome by spring force (see EP 2 210 547 A1), then a sudden acceleration occurs. Door springs are provided to counteract this acceleration. However, such door springs may be misadjusted or may even break. In such case, the door drops down from the closed position to the horizontal and may injure persons as it drops. Small children present in the pivoting range of the door might even be struck dead.
German Patent Application No. DE 10 2008 058 257 A1 describes an automatic washing machine where the latching mechanism is mounted in the door. This automatic washing machine is also provided with a system for automatically opening the door to an ajar position. In this system, part of the latching mechanism is moved out of the body of the machine by a motor. The door remains latched until a release device is actuated.
DE 20 2007 006 818 U1, WO 2009/106 292 A1, EP 1 935 313 A1, which are incorporated by reference herein in their entireties, describe appliance doors openable by knocking on a decorative front panel of the door.
In an embodiment, the present invention provides an automatic warewashing machine including a washing chamber, a hinged door configured to close the washing chamber, and a force-locking latching mechanism configured to hold the door in a closed position and release the door in response to a pulling force. The force-locking latching mechanism is disposed on the washing chamber or on a body enclosing the washing chamber. A door opening system is also included and has a push-open unit configured to automatically open the door to at least an ajar position. The push-open unit includes a motor-driven push-type opening bar.
Exemplary embodiments of the present invention are described in more detail below and are schematically shown in the drawings, in which:
In an embodiment, the present invention provides an automatic warewashing machine which overcomes the aforedescribed disadvantages and has an opening system that is simple in design and easy and safe to operate.
Automatic slow opening is made possible by mounting the latching mechanism on the washing chamber or on the body and providing the push-open unit with a motor-driven push-type opening bar. In this manner, the acceleration of the door during opening is kept low.
In order to provide even greater protection against excessively rapid opening of the door, the door may be retainable on the push-type opening bar by a magnetic coupling.
Furthermore, in an embodiment, the push-open unit of the present invention allows the appliance door opening to be opened at different speeds. This is advantageous in particular in the variant of a handle-free, fully integrated dishwasher. The appliance door should be opened quickly, for example, when a request for opening the door is made by knocking on the decorative front panel of the appliance door. In contrast, at the end of a cycle, the door may be opened relatively slowly. In this manner, the drying of the items washed is significantly improved (see U.S. Pat. No. 5,901,746 A, which is incorporated by reference herein in its entirety). This variation in the opening speed is made possible by the motor drive of the push-type opening bar, for which different motor variants can be used. Conveniently, a double-coil synchronous motor is used in the case of conventional dishwashers, while in the case of fully integratable dishwashers, an extra low voltage DC motor is used. As for the positioning of the motor, it is advantageous if the axis of rotation of the motor shaft extends parallel to the direction of movement of the push-type opening bar. In automatic warewashing machines of conventional design, sufficient space for accommodating a motor is available only laterally between the washing tub and the housing wall. Therefore, in particular elongated motors are preferably only be mounted in the aforesaid position.
Another advantage of embodiments of the present invention resides in the space gained on the door, which allows a deeper handle recess to be formed thereon. Besides, one locks design can be used both for appliances having an exposed control panel and for fully integrated variants. Moreover, there is no need to modify the structure of the latching mechanism for automatic warewashing machines that are not equipped with an automatic opening system. A latching mechanism having a simple design includes a resiliently mounted roller which engages with a lock catch 22 provided on the door. Further structural advantages result from the fact that the latching mechanism and the push-open unit are two independent assemblies which, therefore, can be installed and inspected independently of each other. It is also advantageous if the latching mechanism is arranged in a corner formed by the push-type opening bar and a driving shaft acting upon the push-type opening bar. In this manner, a space-saving design is achieved. The push-type opening bar and the driving shaft may be disposed in an angled housing.
Advantageously, door lock 3 is disposed centrally in a U-shaped strengthening channel 14 of washing chamber 10 of dishwasher 1. Push-open unit 5 and door lock 3 are not connected to each other and, therefore, constitute two independent assemblies, which also simplifies the development of design variants. For example, push-open unit 5 can also be used in dishwashers 1 having a force-locking door lock 3 provided on the door. Further, door lock 3 may also be used without a push-open unit 5 if required, for example, in inexpensive dishwashers 1. If the aforementioned advantages provided by the separate design of door lock 3 and push-open unit 5 are not considered essential, these two assemblies may also be combined into one unit.
Further details of push-open unit 5 are shown in the top view of
The torque of motor 506 is transmitted to push-type opening bar 504 by transmission stages 510 and a shaft 512 disposed at a right angle relative to motor shaft 508 and to the direction of movement of push-type opening bar 504. Transmission stages 510, on the one hand, perform a gear reduction function; i.e., a speed-reducing function, and, on the other hand, they deflect the axis of rotation at an angle of 90° by means of a bevel gear or worm gear stage. At its left end; i.e., at its motor end, shaft 512 is supported directly in lower housing part 500. At its right end; i.e., at the opening bar end, shaft 512 is supported in lower housing part 500 via end shield 514. In
Shaft 512 has mounted thereon a freewheel 522 (
A double pinion 542 is mounted on an extension 540 of outer sleeve 526 (
Double pinion 542 drives push-type opening bar 504 which, in order to open appliance door 2, presses into the rabbet of inner door panel 20, releasing roller 30 of door lock 3 from lock catch 22. The underside of push-type opening bar 504 has a guide track 556 formed between lateral toothed tracks 544. Guide track 556 is engaged by a locking pin 558 formed on an anchor member 560 (see
All other functions provided by the interaction of locking pin 558 with guide track 556 on the underside of push-type opening bar 504 are also described below.
Appliance door 2 is opened by about 100 mm as push-type opening bar 504 is moved out. Door 2 is magnetically held in this state. To this end, a ferromagnetic metal insert 566 is attached to push-type opening bar 504, and a magnet 24 is disposed at a corresponding position behind the inner door panel so as to cooperate with one another. During automatic opening of appliance door 2, the magnetic holding means ensure that the door is retained in the event it has a tendency to open by itself. This may be necessary, for example, if the door springs are set too weak or are broken. Once the ajar position is reached during automatic opening, the user can fully open the door for unloading and loading of dishware. After the magnetic holding means are separated, push-type opening bar 504 should in any case be returned to the retracted position, even if the user has already turned off dishwasher 1, disconnecting it from the mains power supply. Otherwise there would be a risk of getting injured by the extended push-type opening bar 504 or of damaging the same. In addition, the extended push-type opening bar would hinder the unloading and unloading of dishware.
In order to achieve this, torsion spring 552 located on spring sleeve 554 is tensioned as push-type opening bar 504 is moved out; i.e., during the automatic opening of the door. To this end, spring 552 is secured at its two ends in receptacles on drive dog 550 and end shield 514. As appliance door 2 is fully opened by the user, the aforedescribed magnetic holding means cause push-type opening bar 504 to be pulled out up to a front limit stop. Then, push-type opening bar 504 detaches from door 2 and is retracted by torsion spring 552. This also works when dishwasher 1 is off, which makes it possible to avoid standby consumption, which would be required in alternative, electric motor based approaches for the then required control electronics. Spring sleeve 554 allows compression spring 548 and torsion spring 552 to be arranged on shaft 512 in a space-saving manner and concentrically within one another; i.e., concentrically one over the other. End shield 514, which is rotatably disposed in lower housing part 500, serves to support shaft 512 and to adjust the bias of torsion spring 552.
Push-type opening bar 504 is provided with a resilient stop to allow easy opening of the door by the user during periods when no washing operation takes place, such as in a situation where the washed dishes have been unloaded and new items to be washed need to be loaded. This is achieved by means of a stop spring 572. The two legs 574 and 576 of stop spring 572 are biasingly clamped between two bearing blocks 578 and 580. Front leg 574 can be pressed by about 15 mm rearward by stop 582 of push-type opening bar 504. When the user closes the door, stop 582 of push-type opening bar 504 first contacts front leg 574, and the lock is at the changeover point. In the further sequence of movements, the user pushes the door by about another 5 mm rearward, and roller 30 of door lock 3 drops behind lock catch 22. When appliance door 2 is closed, the so-biased push-type opening bar 504 presses with a force of, for example, 25 N from behind against the door, so that the spring force of push-type opening bar 504 counteracts the closure force of door lock 3, which is 40 N, for example. In this example, the resulting reduced closure force of door lock 3 would be 15 N. Thus, the user can open appliance door 2 particularly easily. When the wash cycle is initiated, the driving mechanism presses push-type opening bar 504 by another 10 mm to the rear end position against the force of stop spring 572, so that it no longer contacts the door. Now, the full closure force of 40 N is exerted by door lock 3 on door 2, which is the force required to ensure tightness of the door seal, so that now the washing operation can be started.
A description of the automatic opening sequence and the subsequent closing operation will be given with reference to
During the washing operation, door 2 is closed; push-type opening bar 504 has been retracted to its end position by the driving mechanism formed by motor 506 and transmission stage 510. There is no contact between door 2 and bar 504. The driving mechanism is at rest; freewheel 522 is located at left stop 532. Locking pin 558 is in position A, and arm 564 of anchor member 560 actuates microswitch 570. To initiate the automatic opening, the driving mechanism is activated, causing push-type opening bar 504 to be released. In this process, stop spring 572 pushes push-type opening bar 504 out of housing 500 and 502. Arm 564 clears microswitch 570, and locking pin 558 moves via B to C. In position C, push-type opening bar 504 has moved out 15 mm, which corresponds to the travel of spring 572. Opening bar 504 initially remains in this position, while freewheel 522 is traversed from left stop 532 to right stop 534. Once right stop 534 is reached, double pinion 542 moves opening bar 504 further in the forward direction; locking pin 558 moves via position D to position E, changing from upper guide slot 584 to middle guide slot 586 in the process. When arrived there, the driving mechanism is reversed and freewheel 522 is traversed from right stop 534 back to left stop 532. Once the entire path through freewheel 522 is traversed, the driving mechanism is stopped. Depending on the adjustment of the door springs, door 2 remains in its position, is slightly pulled back by tensioned torsion spring 552 via opening bar 504, or opens a little further by itself. Accordingly, locking pin 558 either remains in position E, moves to position E.1 (if door 2 is pulled back), or moves to position E.2 (if door 2 opens a little further by itself). Middle guide slot 586 has a bevel 588 at point E.1. When the user presses door 2 closed when in the automatically opened position with push-type opening bar 504 in the extended position, locking pin 558 moves up this bevel as push-type opening bar 504 is pushed in, and then moves through path F.1 to position G. Because anchor member 560 is freely supported in the region of locking pin 558, it allows for the lifting of locking pin 558 on the higher, middle guide slot. As path F.1 is traversed, the torsion spring relaxes, and freewheel 522 is traversed from left stop 532 to right stop 534. Normally, the user will pull the door further open after the automatic opening operation is completed. In this process, push-type opening bar 504 is initially pulled further out by the magnetic coupling until the locking pin reaches point E.2. Then, the magnetic coupling is disconnected. Tensioned torsion spring 552 then pulls opening bar 504 back into housing 5, in which process the locking pin moves, via F, from middle guide slot 586 to lower guide slot 590 and to G, where it is held. As opening bar 504 retracts, freewheel 522 is traversed from left stop 532 to right stop 534. Position G in the middle guide slot is configured as a receptacle in which locking pin 558 is held. Because of this, upon manual opening of the closed door, push-type opening bar 504 is held in this position and prevented from also moving out. Once a new wash cycle is initiated, opening bar 504 is fully retracted again, and locking pin 558 moves via H onto upper guide slot 584 and back to position A. In this process, the freewheel is traversed from right stop 534 to left stop 532.
Door 2 is pulled down to the horizontal position by its own weight already when in a slightly open state. The weight of door 2 is counteracted by conventional door springs. However, when one or even both door springs are broken, the weight is not or not sufficiently balanced anymore. In this case, door 2 is initially held by torsion spring 552 as push-type opening bar 504 moves out. When at a certain opening angle, the weight of door 2 exceeds the retaining force of spring 552, the door accelerates its dropping motion. In the first variant of freewheel 522, the freewheel is traversed from right stop 534 to left stop 532 in this process, and push-type opening bar 504 is fully pulled out up to the stop. The acceleration occurring in this process, and the subsequent sudden deceleration occurring when push-type opening bar 504 reaches the end of its path, may disconnect the coupling between metal insert 566 and magnet 24. In that case, door 2 continues to drop unbraked to the horizontal position and may injure persons or destroy objects on its way.
To avoid this, the variant of freewheel 622 shown in
While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.
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