Stoves and furnaces – Stove doors and windows – Latches
Reexamination Certificate
2000-05-16
2001-10-16
Clarke, Sara (Department: 3743)
Stoves and furnaces
Stove doors and windows
Latches
C292S109000, C292S127000, C292SDIG006
Reexamination Certificate
active
06302098
ABSTRACT:
FIELD OF THE INVENTION
This application relates to a motorized oven door latch assembly for locking an oven door in a closed position when the oven is in a self-cleaning mode.
BACKGROUND OF THE INVENTION
Self-cleaning ovens which are incorporated into self-standing ranges are well known. Such ovens conventionally have an oven door which is hingedly secured to a range body. The oven door may be opened to gain access to an oven cavity. The oven door may also be closed to close the opening for cooking objects placed in the cavity or cleaning the cavity. One or more heating elements reside in the oven cavity for cooking purposes.
Motorized latches which are used to lock oven doors in a closed position so that the oven cavity may be self cleaned are well known. U.S. Pat. No. 3,8659,979 and U.S. Pat. No. RE. 27,545 and U.S. Pat. No. 4,374,320 all disclose such motorized self-cleaning oven door latches. Such oven door latches are activated by a rotary motor located at the rearward portion of the range above the oven. Activation of the motor causes a rod to translate which results in a device at the front of the rod to engage the oven door so that the oven door may not be opened. After the cleaning has occurred, the motor is reactivated, causing the device at the front of the rod to disengage the oven door so that the oven door may be opened.
Using such a motorized latch, when the oven door is locked in a closed position for purposes of self cleaning the oven, the user may not access the oven cavity through the opening covered by the oven door until the motor is reactivated, and the rod translates back to its original position. In the event of an electrical or mechanical failure which prevents the motor from being reactivated, the oven door remains in a locked position such that access to the range cavity is not available except through the rear of the range. With the oven door locked shut, the oven may not be used. In such an event, a service technician must be called to enter the range through the rear of the oven and open the door. The service technician must physically move the range and then use special tools to disassemble the rear of the range to gain access to the oven cavity to open the oven door This process is costly for the range owner and time-consuming. If no service technician is available such as on a Sunday, the oven may not be used for cooking purposes until the service technician comes on Monday to open the oven door. Consequently, a need exists for a motorized latch assembly for a self-cleaning oven which enables a user to open the oven door in the event of an electrical or mechanical failure when the oven is in a self-cleaning mode.
Therefore it has been one objective of the present invention to provide a motorized oven door latch assembly which in the event of failure allows access to the oven through the oven door.
It has further been an objective of the present invention to provide an oven door latch which does not require that the rear of the range be disassembled in the event of failure.
It has further been an objective of the present invention to provide an oven door latch assembly which has a latch at the front of the oven which may be opened with a pry bar type of device in the event of failure, quickly and easily.
SUMMARY OF THE INVENTION
The invention of this application which accomplishes these objectives comprises a motorized door latch assembly for locking an oven door in a closed and sealed position so as to close an oven cavity for purposes of cleaning the oven cavity. The oven door is hingedly mounted on a range body and moveable between an open position, a closed position and a closed and sealed position.
The door latch assembly comprises a mounting plate supported by the range body above the oven cavity and extending generally from front to back. Proximate the front of the mounting plate is a pin extending upwardly from the mounting plate. The pin may be intricately formed with the mounting plate or a separate element secured to the mounting plate in any number of ways, including, but not limited to, being welded to the mounting plate.
Proximate the rear of the mounting plate, a motor is supported by the range body. The motor is preferably located above and behind the range cavity but may be located at any other location. The motor rotatively drives a cam, operatively associated with the motor.
A latch rod, having a pair of opposed ends, extends between the cam and a latch plate located at the front of the range. The latch rod has a first end secured to the rotatable cam and a second end secured to a latch plate. Rotation of the cam causes the latch rod to translate either forwardly or rearwardly. Other devices, such as for example a solenoid, may be used to cause the latch rod to translate.
The latch plate has a hook at one end for engaging the oven door and a hole at the other end. The second end of the latch rod passes through the hole of the latch plate and through a guide formed in the mounting plate so as to secure the second end of the latch rod to the latch plate and limit movement of the latch plate upon translation of the latch rod. The latch plate also has a slot therethrough in which the pin extending upwardly from mounting plate travels. The size of the slot and location of the pin restrict the movement of the latch plate so as to move the latch plate between three desired positions.
In operation, rotation of the cam by activation of the motor causes the latch rod to translate generally from back to front and causes the latch plate to move between three positions: a first position, a second position and a third position. In the first position, the latch plate is located such that the oven door may be opened. Upon translation of the latch rod, the latch plate moves to a second position in which the hook of the latch plate engages the oven door to prevent the oven door from being opened. In the third position, the latch plate is pulled inwardly by the latch rod, pulling the oven door into a locked and sealed position.
A biaser extends between a fixed point on the mounting plate and the latch plate so as to bias the latch plate towards the second position described hereinabove. In the event of a failure while the oven is in a self-cleaning mode with the latch plate in its third position and the door locked and sealed, a user, using a pry bar tool may exert pressure on the hook of the latch plate causing the latch plate to rotate about the pin of the mounting plate toward the first position. With the latch plate pulled over to its first position the oven door may be opened without having to call a service technician.
REFERENCES:
patent: Re. 27545 (1973-01-01), Guy
patent: 3125365 (1964-03-01), Eigelbach
patent: 3859979 (1975-01-01), Gilliom
patent: 4374320 (1983-02-01), Barnett
patent: 5029910 (1991-07-01), Genbauffe et al.
Clarke Sara
France/Scott Fetzer Company
Wood Herron & Evans L.L.P.
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