US3469568A

US3469568A - Door locking means and associated control circuit for self-cleaning oven

Info

Publication number: US3469568A
Application number: US733422A
Authority: US
Inventors: Sumner H Torrey; Donald J Dubuque; Norman R Sloan; Robert L Morris
Original assignee: Geo D Roper Corp
Current assignee: Geo D Roper Corp
Priority date: 1968-05-31
Filing date: 1968-05-31
Publication date: 1969-09-30
Anticipated expiration: 1986-09-30

Description

Sept. 30, 1969 5, H, TORREY ETAL 3,469,568

DOOR LOCKING MEANS AND ASSOCIATED CONTROL CIRCUIT FOR SELF-CLEANING OVEN Filed May 31, 1968 3 Sheets-Sheet 1 r l l l l? /1 'alti (gli T. Nl

35 [Sigo IN vENToRs ,Saunen H. ToRREY DONALD J, DUBUOUE NORMAN' R. SLoAN Sept. 30, 1969 s, H TQRREY ET Al. 3,469,568

DOOR LOCKING MEANS AND ASSOCIATED CONTROL CIRCUIT FOR SELF-CLEANING OVEN Filed May 3l, 1968 3 Sheets-Sheet 2 Invanrons SUMMER H. ToRReY DouALo J. Duuaue NORMAN R. SLoAN Roesn'r L, MoRRls Sept. 30, 1969 s, TORREY ET AL 3,469,568

DOOR LOCKING MEANS AND ASSOCIATED CONTROL CIRCUIT FOR SELF-CLEANING OVEN Filed May 3l, 1968 3 Sheets-Sheet .j

FIGS

e I( 'III` FIG] INVENroRs SUMNER H. ToRREY DONALD J. DueuQuE NORMAN R. SLoAN ROBERT L. MORRIS United States Patent 3,469,568 DOOR LOCKING MEANS AND ASSOCIATED CON- TROL CIRCUIT FOR SELF-CLEANING OVEN Sumner H. Torrey and Donald J. Dubuque, Kankakee, Norman R. Sloan, St. Anne, and Robert L. Morris, Kankakee, Ill., assiguors to Geo. D. Roper Corporation, Kankakee, Ill., a corporation of Delaware Filed May 31, 1968, Ser. No. 733,422 Int. Cl. F24c 3/00, 15/02; A211) 1/00 U.S. Cl. 126-39 10 Claims ABSTRACT OF THE DISCLOSURE A self-cleaning range having an oven cavity and a broiler cavity with a mechanical lock for locking both of them simultaneously during the cleaning cycle and with a control circuit so arranged that both doors must be closed and locked for a cleaning cycle to be initiated. Electrical interlock switches are associated with the doors and enablingly connected to the thermostat when the later is turned to the upper end of its range.

It is an object of the present invention to provide a novel mechanical locking arrangement for both the oven door and the broiler door during a self-cleaning cycle and which has provision for insuring that both doors are closed and locked before the self-cleaning cycle may be initiated. It is a related object to provide a mechanical lock for an oven door with a mechanical interlock extending to the broiler door, and with the doors being provided in addition with electrical interlocks for effectively disabling the source of heat unless and until both doors are closed and locked. In this connection it is a more specic object to provide a door interlocking and latching arrangement for adjacent oven and broiler cavities which are heated during normal usage and self-cleaned by the same broiler burner.

In general it is an object of the invention to provide both electrical and mechanical interlocks for associated oven and broiler doors with an associated selector for selecting between the various modes of operation which combines a high degree of safety with inherent mechanical and electrical simplicity.

Other objects and advantages of the invention will become apparent upon reading the attached detailed description and upon reference to the drawings in which:

FIGURE 1 is a side sectional view of a range employing the present invention and taken along the line 1--1 in FIG. 2;

FIG. 2 is a front sectional view taken along the line 2 2 in FIG. l;

FIG. 3 is a perspective view of the mechanical locking and interlocking arrangement employed in the present invention;

FIG. 4 is a plan view of the lock body showing the lock member in latched condition;

FIGS. 5, 6 and 7 show a circuit diagram comprising part of the present invention under conditions of baking, self-cleaning, and cooling, respectively, with the active portion of the circuit indicated by the bold lines; and

FIG. 8 is a diagram showing a typical control used in the above circuit.

While the invention has been described in connection with a lpreferred embodiment there is no intention to be limited to the embodiment shown but it is intended, on the contrary, to cover the various alternative or equivalent constructions included Within the spirit and scope of the appended claims.

Turning now to the drawings there is disclosed in FIG- URES 1 and 2 a free-standing range 10 having a frame 3,469,568 Patented Sept. 30, 1969 ICC 11 defining an oven cavity 12 and a broiler cavity 13. The latter are enclosed by

doors

14, 15. For heating the oven cavity, and for purposes of broiling in the lower cavity, a gas burner 20 is provided having an inlet manifold 21 which is connected via an electric valve, as will appear, tothe usual domestic gas line.

As shown in FIG. 2, the oven is of the muffled type in which the heated air and products of combustion do not enter the oven cavity but are, instead, directed through passageways 22-24 at the sides, top and back, discharging into a flue 25 which has a vent 26 above the level of the cooking top. The oven cavity has a catalytic smoke eliminator 30 with an inlet opening 31 and an outlet 32 which discharges into the same flue structure 25 adjacent a barrier 33 to prevent products of combustion and associated air from entering the oven cavity.

Arranged below the broiler burner 20 is a drip pan 35 having a rack 36, the drip pan 35 being supported in a sliding drawer 37. The broiler door 15 and the drawer 37 are connected together along a hinge 38 so that when the door is pulled outwardly it tips forward while pulling the drawer 37 into full view. The door 14 which encloses the oven cavity is pivoted to the frame along a hinge axis 39. To understanding more fully the details of the range construction, reference is made to copending application Serial 733,433, iiled May 31, 1968.

A control circuit is provided for modulating the admission of gas to the burner under normal baking conditions as shown in FIG. 5, the active portion of the circuit during baking being indicated by the bold lines. It will be helpful to have this control -circuit in mind in order to understand the mechanical and electrical interlocking devices which are to be described and which distinguish the present invention. Two manually settable controls are preferably provided, an oven control and a selector switch. The oven control, indicated at 40, includes a thermostat T having a contact 41. The thermostat T corresponds to the usual oven control thermostat except that, in addition to having a lower range covering the usual cooking temperatures, it is settable to a high range during the self-cleaning cycle. A normally open contact 42 closes when the control is in its low range and a normally open contact 43 closes when the control is set to its high range. An auxiliary thermostat AT, having a normally closed contact 44, is used to prevent opening of the oven under high temperature conditions as will appear.

For selecting the mode of oven operation a selector switch 50 is provided having normally open

contacts

51, 52, 53. The switch is provided with a 4-position selector knob which provides a time bake mode with all of the switches open, a bake mode with switch 51 closed, a clean mode with switch 52 closed and an unlock or cooling mode with switch 53 closed. For timing the baking and cleaning operations, a time clock 60 is used having a motor winding 61 and having a normally open contact 62 which supplies a timed bus 63. An electric gas valve 65 controlled by the contacts 41 of the thermostat, and in series with the usual ame switch 66, permits passage of gas to the burner when the valve is energized.

Under non-timed baking conditions shown in FIG. 5 a circuit is established through

contacts

51 and 42 thence through contacts 41 on the thermostat T to turn on the gas valve 65, the gas flowing to the burner being lit by a suitable pilot P, and with the valve being thereafter cycled automatically by the thermostat to maintain the set temperature.

In accordance with the present invention a mechanical locking arrangement is provided for both the oven and broiler doors with electrical interlock switches which are effective, when both of the doors are closed and locked and when the oven control is set in its high range, to complete a circuit from the thermostatto the gas control valve for heating of the oven and broiler cavities to a selfcleaning temperature. More specifically, a mechanical lock is provided for the oven door having an interlock for engaging the broiler door with electrical interlock switches for initiating the flow of gas and with a latch for maintaining both doors closed and locked until such time that the temperature is again reduced to a safe level. Thus, referring to FIG. 3, the oven door 14 is provided with a lock 70 in the form of a rotary striker 71 mounted on a shaft 72 and manually operated by a handle 73. For receiving the striker there is mounted in the frame of the oven a lock body 75 having a receiving slot 76 which is positioned to receive the striker when the door is closed. For simultaneous locking of the broiler door 15, a mechanical interlock is provided in the form of a rod 80 having its upper end 81 cranked with respect to the striker 71 and having its lower end 82 -movable between the retracted position shown in the drawing and a projecting position in which the lower end extends into an opening 83 in the upper edge of the broiler door and into obstructing position with respect to a striker plate 84 mounted in the door. Telescoped over the end of the rod is a return spring 85.

For the purpose of maintaining the striker captive within the lock body, a lock member, or lever, 90 is provided centrally pivoted at 91 and having a striker-receiving notch 92 at its forward end. The lock member is held in the receptive position shown by means of a return spring 93. It will be apparent that when the striker is rotated into the slot 76 and engaging the notch 92, the lock member will rotate counterclockwise into a latched position. For latching the lock member a latching rod 94 is provided having a tip 96 which rides against a land 96 until reaching a point of drop-off 97. When the point of drop-off is reached, the latching rod moves forwardly under the urging of a spring 98 for positive holding of the member 90 in its locking position shown in FIG. 4.

For insuring that both doors are closed and locked before gas is admitted to the burner 20 to begin the selfcleaning cycle, a single pole, double-throw switch 100 is provided having normally closed contacts 101 and normally open contacts 102, which switch is in the path of movement of the lock member 90 and operated incident to moving the member into its fully latched position. In addition a normally open switch 103 having contacts 104 is mounted so as to be responsive to complete closure of the broiler door. The switch is preferably mounted in the door jam with a forwardly extending actuator 105 facing the backside of the door.

To initiate a self-cleaning cycle (see FIG. 6), the oven control 40 is set at the high cleaning range. This, as stated, closes contacts 43 in the oven control. Moving the selector switch 50 to its third or clean position closes contacts 52. Rotating the door handle 73 to the clean position with the broiler door closed, not only locks, and latches, both doors but causes

contacts

102, 104 of the interlock switches to be closed which completes an electrical circuit from the clock contacts 62 through the thermostat contacts 41 to the electric valve 65. As a final step, the time clock 60 is set to the desired cleaning interval closing the contacts 62 and energizing the bus 63 to open the electric valve to begin the cleaning cycle. A circuit is simultaneously completed to the heater 106 in the smoke eliminating, or catalytic, unit 30. With the broiler burner on, the temperature within the oven and broiler cavities quickly rises to the self-cleaning level which may, for example, be 750 to 900 F. where cycling will take place under the control of the thermostatically operated contacts 41. When the clock has timed out the interval, contacts 62 open thereby de-energizing the electric valve 65 which turns olf the gas permitting the oven and broiler cavities to cool.

In carrying out the invention an auxiliary thermostat is provided which closes when the temperature is reduced to a safe level and which, acting through unlock contacts in the selector switch, energizes a latch release solenoid to release the latching rod 94, thereby to permit the oven lock to be manually rotated to its unlocking position. To establish this unlocking mode, the selector switch is moved to its fourth or unlock position closing contacts 53 which are connected to a solenoid 110, the armature of which is pinned to the rear end of the rod 94. When a safe oven temperature is reached, which may be approximately 550 F., closure of contacts 44 on the thermostat AT, completing the circuit shown in FIG. 7, energizes the solenoid 110 so that the latching rod is moved out of its obstructing position. Cleaning completed, the oven and broiler may thereaftre be used in the regular way.

For indicating that the oven and broiler are at an elevated temperature, and that the doors :are latched in closed position, a lock indicator is provided which is preferably in the form of a gaseous discharge lamp energized through a high value series resistor 116 and with the lamp being connected in parallel with the contacts 44. Thus, as long as these contacts are open, indicating that the temperature is at a high level, the lamp is turned on, but when the contacts close the lamp is shorted out and thus extinguished, indicating that the selector switch can be moved to the unlock position.

The combination of mechanical and electrical interlocking described above produces a safety system which has a high degree of reliability and which is practically impossible to defeat. The gas cannot be turned on for a self-cleaning cycle unless all of the conditions for safety have been fulfilled, i.e., unless both doors are fully closed and unless the rotary striker is fully bottomed in the receiving slot in the frame. It is only then that the electrical interlock switches are actuated to complete the circuit between the oven control thermostat and the electric gas valve. Moreover the controls are eminently simple so that no question is raised in the mind of the user. To establish the cleaning cycle the oven control is rotated to the high end of its range, preferably designated by the word clean, and the selector switch is similarly moved Ato its clean position. Setting the cleaning interval on the time clock turns the burner on. It is only after the indicator lamp goes out, indicating that the temperature has been reduced to a safe level, that moving the selector switch to the unlock mode is capable of energizing the latch releasing solenoid. Such foolproof operation has -been achieved at low cost using a mechanical lock having a minimum number of parts and using readily obtainable switch elements.

In the following claims the term striker will be understood to mean any bolt-like locking element. The term latch is intended to include any means for insuring that the door lock continues to be engaged while the oven and broiler are at elevated temperature. The term rod is intended to cover a force transmitting member. Also, the term enabling shall be understood to mean conditioning for operation, the opposite of disabling the term electric valve has to do with an electrically operated gas supply valve either electro-magnetic or the electrically heated bi-metal type while the term slot is intended to denote any recess in which the striker is received.

We claim:

1. In a self-cleaning gas range, the combination comprising a frame having an oven cavity and a broiler cavity arranged below it each having a closeable door, means including a broiler burner for heating the cavities, a mechanical lock including a manually operated striker in the oven door cooperating with a slot in the frame, a mechanical interlock including a rod in the oven door coupled to the striker for movement therewith and having means at its lower end for lockingly obstructing the broiler door when the striker is moved to its locking position, means including an electric gas valve for passing gas to the burner, oven controller means including a thermostat for controlling the electric valve, Contact means for completing a circuit from the thermostat to the electric valve during the time that the oven controller means is set in its normal baking range, means including interlock switches associated with the mechanical lock and broiler door respectively and actuated when the doors are closed and locked for completing the circuit from the thermostat to the electric valve when the thermostat means is set at the upper end of its range to achieve and maintain a self-cleaning temperature, means for turning olf the gas after a predetermined length of time', and means for latching the doors closed until the temperature drops below the self-cleaning level.

2. In a self-cleaning gas range, the combination comprising a frame having an oven cavity and a broiler cavity arranged below it, each having a closeable door, a broiler burner for heating the cavities, an oven controller including thermostat means manually settable for maintaining a temperature in a baking range and a high selfcleaning temperature, said oven door having a mechanical lock and said broiler door having an interlock coupled to the lock for maintaining the doors locked during a self-cleaning cycle, means including electrical interlock switches respectively associating with the doors and operated incident to closing and locking both of the doors for enabling control of the burner by the thermostat means when the controller is set for the self-cleaning temperature, and means for latching the mechanical lock in closed position during the time that the temperature is above the baking range.

3. In a self-cleaning gas range, the combination comprising a frame having an oven cavity and a broiler cavity arranged below it each having a closeable door, a broiler burner for heating the cavities, a mechanical lock including a manually operated rotatable striker in the oven door cooperating with a slot in the frame, a reciprocable push rod in the oven door having a cranked connection with the rotatable striker at its upper end and having means at its lower end for obstructing the broiler door when the striker is moved to locking position, means including a controller having a thermostat and settable to a high level for operating the burner to achieve a seltcleaning temperature, means including electrical interlock switches associated with the respective doors and operated when theI doors are closed and locked for enabling operation of said thermostat, means for turning olf the gas after the self-cleaning temperature has been maintained for a `predetermined length of time, and means for latching the striker in locking position during the time that the temperature in the oven cavity is above a predetermined level.

4. In a self-cleaning gas range, the combination cornprising a frame having an oven cavity and a broiler cavity arranged below it, each having a closeable door, a broiler burner for heating the cavities, said oven door having a mechanical lock including a manually operated rotary striker in the door cooperating with a slot in the frame, a movable locking member adjacent the slot for receiving the tip of the striker and for holding it captive in the slot, a mechanical interlock including a rod in the oven door having a cranked connection with the striker at its upper end and having means at its lower end for obstructing the broiler door when the striker is moved to locking position, a latch for latching the locking member, controller means including a thermostat and electric valve associated with the burner for causing the latter to deL velop a self-cleaning temperature in the cavities, electrical interlock switch means operated when the doors are closed and locked for enabling the thermostat to maintain a high self-cleaning temperature, means for turning ot the burner after the self-cleaning temperature has existed for a predetermined length of time, and means operated incident to a drop in temperature to below the self-cleaning level for releasing the latch thereby to permit manual opening of the door.

5. In a self-cleaning gas range, theI combination comprising a frame having an oven cavity and a broiler cavity arranged below it each having a closeable door, a

broiler burner for heating the cavities, a mechanical lock for simultaneous locking of both of the doors and manually throwable from open to locked position, an oven controller including a thermostat and solenoid valve for supplying gas to the burner, said controller being settable to a baking range and a high self-cleaning temperature, a first switch contact on the controller for establishing a circuit between the thermostat and electric valve when the thermostat is set within its baking range, a second switch contact on the controller arranged for closure when the controller is set at the self-cleaning temperature7 electrical interlock switch means associated with said doors and operated when the doors are closed and locked, said electrical interlock switch means being connected in series with the second switch contact to prevent turning on of the burner and achieving of a self-cleaning temperature until the doors are closed and locked, means for turning olf theI burner after passage of a predetermined time at the self-cleaning temperature, and means including a latch for maintaining the lock in locked condition as long as the temperature is above a predetermined level and for releasing the latch when the temperature is reduced below such level.

6. In a self-cleaning gas range, the combination comprising a frame having an oven cavity and a broiler cavity arranged below it each having a closeable door, la broiler burner for heating the cavities, means including a mechanical interlock between the doors for locking both of the doors simultaneously, means including an electric gas valve for passing gas to the burner, an oven controller including a thermostat settable to a high and low range, a selector switch settable between bake, clean, and door unlock modes and having rst, second, and third contacts respectively closed in such modes, a bake circuit including the first contact for operatively connecting the thermostat to the electric valve when the thermostat is in its low range, electrical interlock switch means associated with said doors and arranged for actuation when the doors are closed and locked, a clean circuit including the second contact for connecting the thermostat and the interlock switch means in operative series connection with the electric valve when the thermostat is in its high range to establish a high self-cleaning temperature, means including a latch for holding the locking means in locked condition and having an associated unlocking solenoid for releasing the latch, means for turning off the ilow of gas after a predetermined length of time at self-cleaning temperature, an auxiliary thermostat arranged to close when the temperature falls below the self-cleaning temperature, and a door unlock circuit including the third contact for coupling together the auxiliary thermostat and the unlocking solenoid for unlatching the lock when the temperature is safely below the self-cleaning temperature.

7. In a self-cleaning gas range, the combination comprising a frame having an oven cavity and an adjacent broiler cavity each having a closeable door, burner means for heating the cavities, -a mechanical lock including a manually operated striker in one of the doors cooperating with a recess in the frame, a mechanical interlock coupled to the striker and extendable into obstructing relation with the other door for holding the other door closed as long as the said one door is closed Iand locked, means including a gas valve for passing gas to the burner means, oven controller means including thermostat means selectively settable to maintain a baking temperature and a high self-cleaning temperature, means including an interlock switch actuated when both of the doors are closed and locked for completing a circuit from the thermostat means to the electric valve to turn on the gas when the thermostat means is set to the high self-cleaning temperature, means for turning ofr" the ow of gas after the high temperature has existed for a predetermined length of time, and means for maintaining the mechanical lock in locked condition until the temperature falls to a predetermined safe level.

8. In a self-cleaning range, the combination comprising a frame defining an oven cavity having a closeable door, a burner for heating the cavity, said oven door having a mechanical lock including a manually operated rotary striker in the door cooperating with a slot in the frame, a pivoted locking member adjacent the slot having a notch for receiving the tip of the striker and movable therewith into a locking position in which the striker is captive in the slot, a latch for latching the locking member in locking position, controller means including a thermostat arranged to control the burner for causing the latter to develop a self-cleaning temperature in the cavity, an electrical inerlock switch in the path of movement of the locking member and closed as the locking member moves into its locking position for coupling the thermostat to the burner, means for turning off the burner after the selfcleaning temperature has existed for a predetermined length of time, and means operated incident to a drop in temperature to below the self-cleaning level for releasing the latch thereby to permit manual opening of the door.

9. ln a self-cleaning oven assembly, the combination comprising a frame defining an oven cavity having a closeable door, a burner for heating the cavity, a rnechanical lock for locking the door and manually throwable from open to locked position, means including an oven controller having a thermostat controllably coupled to the burner for controlling the heat output thereof, said controller being settable to a baking range and a high selfcleaning temperature, normally open and normally closed switch contacts actuated incident to closing and locking the door, a first switch contact on the controller closed when the thermostat is set within its baking range, a second switch contact on the controller closed when the controller is set at the self-cleaning temperature, a baking circuit including the first switch contact on the controller and said normally closed contact for coupling the thermostat to the burner to establish a baking ternperature, and a self-cleaning circuit including the second switch contact on the controller and said normally open contact for coupling the thermostat to the burner thereby to prevent turning on of the burner and achieving of a self-cleaning temperature until the door is closed and locked, means for turning off the burner after passage f a predetermined time at the selfcleaning temperature, and means including a latch for maintaining the lock in locked condition as long as the temperature is above a predetermined level and for releasing the latch when the temperature is reduced below such level.

1). In a self-cleaning oven assembly, the combination comprising a frame defining an oven cavity having a closeable door, a burner for heating the cavity, a mechanical lock for locking the door and throwable manually from open to locked position, means including an oven controller having a thermostat controllably coupled to the burner for controlling the heat output thereof and settable to a high and low range, a selector switch settable between bake, clean, and door unlock modes and having first, second, and third contacts respectively closed in such modes, a bake circuit including the rst contact for operatively coupling the thermostat to the burner when the thermostat is in its low range, an electrical interlock switch associated with the lock for actuation when the door is closed and locked, a clean circuit including the second contact and the interlock switch for coupling the thermostat to the burner when the thermostat is in its high range to establish a high self-cleaning temperature, means including a latch for holding the lock in locked condition and having an associated unlacthing solenoid for releasing the latch7 means for turning off the burner after a predetermined length of time at selfcleaning temperature, an auxiliary thermostat arranged to close when the temperature is safely below the self-cleaning temperature, and a door unlock circuit including the third contact for connecting the auxiliary thermostat and the unlocking solenoid for unlatching the lock when the temperature drops to below the safe value.

References Cited UNITED STATES PATENTS 3,050,048 8/1962 Scott 126--273 3,364,912 1/1968 Dills etal.

3,406,677 10/1968 Anderson 126--273 X 3,416,515 12/1968 Mettler 126-273 CHARLES I. MYI-IRE, Primary Examiner U.S. C1.X.R. 126-197, 273