US3648011A

US3648011A - Oven latch operated feature switch

Info

Publication number: US3648011A
Application number: US45097A
Authority: US
Inventors: Calvin J Holtkamp
Original assignee: Westinghouse Electric Corp
Current assignee: Westinghouse Electric Corp
Priority date: 1970-06-09
Filing date: 1970-06-09
Publication date: 1972-03-07
Anticipated expiration: 1989-03-07
Also published as: CA938970A

Abstract

A switch means which may be added to the latch arrangement of an oven having a cleaning mode where the oven latch is moved to an engaged and locked position in such a mode. The switch means is physically actuated by this movement and can be utilized, advantageously, either as an engagement or a disengagement means for some portion of the oven control system thereby eliminating the use of a selector switch requiring several additional terminals and the resulting cost of an additional terminal selector switch.

Description

United States Patent Holtkamp 1 1 Mar. 7, 1972 [54] OVEN LATCH OPERATED FEATURE 3,474,226 10/1969 Kauranen ..2l9/413 SWITCH 3,390,909 7/1968 Nagel ..2l9/4l3 X 3,549,862 12 1970 H ltk tal. ..2l9 519 X [72] inventor: Calvin J. lloltkamp, Mansfield, Ohio 0 amp e l [73] Assignee: Westinghome Electric Corporation, Pitt- Primary Examiner-Volodymyr Y. Mayewsky sburgh, Pa. Attorney-F. H. Henson, E C. Arenz and R. B. Farley [22] Filed: June 9, 1970 l 57] ABSTRACT 21 A l.N.:45097 I 1 pp 0 A switch means which may be added to the latch arrangement of an oven having a cleaning mode where the oven latch is l U-b. 2 2 moved (9 an engaged and locked position in such a mode The [Si I Int. Cl. ..F27d 11/02 switch means i physically actuated by this movement d can [581 Md of Search 2 6 be utilized, advantageously, either as an engagement or a dis- 51 1 397 engagement means for some portion of the oven control system thereby eliminating the use of a selector switch requir- [56] Rem-em Cited ing several additional terminals and the resulting cost of an ad- UNITED STATES PATENTS ditional terminal selector switch.

3,350,542 10/1967 Getman ..2 19/412 6 Claims, 9 Drawing Figures Patented March 7, 1972 3,648,011

4 Sheets-Sheet l 42 O O FIXED 3o 0- 30% MOVABLE J FIG. 2

FIG. 3

Patented March 7, 1972 3,648,011

4 Sheets-Sheet 2 INDICATOR Patented March 7, 1972 4 Sheets-Sheet 4 LIN lhDlCATOR OVEN LATCH OPERATED FEATURE SWITCH BACKGROUND OF THE INVENTION 1. Field ofthe Invention This invention relates to electrically operated ovens having a cleaning cycle and, more specifically, relates to the addition of a feature switch actuated by the locking mechanism which must be engaged to initiate the clean cycle for the oven.

2. Description of the Prior Art Prior designs of self-cleaning ranges and their electrical circuitry such as are disclosed in U.S. application No. 773,539, filed Nov. 5, 1968, now U.S. Pat. No. 3,549,862 and owned by a common assignee have permitted the lock light to be operable (lit) during dual broil element operation (where opposite faces of a food article are simultaneously broiled) since it was felt that such operation would not constitute an undue customer nuisance. However, actuation of this light during the dual broil operation has incurred field problems due to the housewife-operator believing that the oven is not properly operating when this light comes on during the dual broil operation. Therefore, some positive means (another feature) should be provided in such a circuit for operation of the lock light only in the clean mode of the oven.

An additional feature which is also required in some oven circuits is a method for cleaning the surface unit drip pans during the oven-cleaning operation by inserting these within the oven cavity. If these unit drip pan are placed in the oven, itself, during the heating cycle for cleaning purposes, an electrical cutout switch forinactivating an oven surface unit is required to insure operating safety and prevent the surface unit from igniting combustibles remaining in the exhaust from the oven which passes outwardly through this surface unit.

Another feature which may be desired is a fan for the circulation of cooling air within ports of the oven cabinet housing. In certain ovens this fan would safely limit the top temperature reached by the outside surfaces of the oven cabinet during the cleaning mode.

' In each of these enumerated cases, additional circuitry must be provided in the oven operating circuit to insure that the particular feature desired has the required operative terminals, switches, leads, etc. One method of obtaining these additional features would be the provision of an additional set or sets of terminals on the selector switch which is utilized to control all of the operations of the oven; i.e., bake, time bake, boil, dual or auxiliary broil and clean. However the use of such an additional group of terminals on the selector switch would necessitate the purchase or fabrication of a selector switch having a much higher cost than the selector switches having only the aforementioned functions which are now standard for oven control circuits. It would, therefore, be advantageous to provide any one of the aforementioned features by the use of a simple, inexpensive switch means which would operate in conjunction with the oven clean cycle so as to eliminate the added cost of a selector switch providing the additional feature.

SUMMARY OF THE INVENTION The instant invention adds a latch-operated switch means to self-cleaning oven circuitry to provide the control system of the oven with an additional feature or features not easily ob-, tainable by the addition of two or more terminals to a presently utilized selector switch.

In the first embodiment of the invention, a latch operated feature switch is added to a single peak self-cleaning oven circuit such as disclosed in the application Ser. No. 773,539 filed Nov. 5, 1968, now U.S. Pat. No. 3,549,862 and owned by a common assignee.

The feature switch is added by providing an indicating light to the arrangement disclosed in the foregoing application which connects to neutral and L of a three-line supply system, with the switch means being physically disposed on the locking bar arrangement of the oven so as to be actuated whenever the oven is placed in the clean mode with the latching arrangement latched. The switch means permits the flow of current from L through a fan motor and/or lock light to the neutral line and thereby actuates the fan motor and door lock indicating light provided as additional elements that are shunted when a lock switch of the circuitry is closed.

In a second embodiment of the invention, a latch-operated switch arrangement for deactivation of a surface unit is provided in the heat-cleaning circuit for an oven with this heat cleaning circuit operative on a time basis to provide the cleaning function for an oven cavity. Such an arrangement without the additional feature is generally disclosed in an oven circuit seen in U.S. Pat. application No. 552,663 filed Apr. 26, 1966, now U.S. Pat. No. 3,504,166 and owned by a common assignee. In this second embodiment, a somewhat similar, improved circuit is described which includes the deactivation feature for the surface unit provided by a switch means operated by the latching arrangement.

In a third embodiment of the invention, an oven circuit similar to that disclosed in the second embodiment is provided. However, in this embodiment, a pilot light indicating that the oven is in the clean mode replaces the surface unit deactivation feature of the second embodiment but the pilot light is still activated by a latch operated switch means.

DRAWING DESCRIPTION For a better understanding of the invention, reference may be had to the preferred embodiments, exemplary of the invention, shown in the accompanying drawings in which:

FIG. 1 is a side elevational view ofa range of the heat-cleaning type incorporating the invention;

FIG. 2 is a fragmentary horizontal sectional view corresponding to one taken along the line IIII of FIG. 1 and illustrating the latching means and the forward part of the link means in a latched condition;

FIG. 3 is a fragmentary enlarged rear elevational view of the lock assembly and the rear part of the link means of the lock assembly located at the rear of the range with the included switch means of the invention;

FIG. 4 is a top plan view of the elements shown in FIG. 3 but also showing the elements there in latched position in dotted lines;

FIG. 5 is a view of the circuitry of the first embodiment of the invention;

FIG. 6 is a table which indicates those contacts of the selector switch means which are closed for particular settings of it;

FIG. 7 is a view of the circuitry of the second embodiment of the invention;

FIG. 8 is a table similar to FIG. 6, but showing the active contacts of the selector switch means for the second and third embodiments of the invention; and

FIG. 9 is a view of the circuitry of the third embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention will now be described with particular reference to the drawings in which FIGS. 14 illustrate the physical location of the switch means 10 and its relationship to the latching means 12 of an oven 14. The latching means 12 includes a handle 16 which, by rotation of about a quarter of a a turn, actuates the remainder of the latching means to place an oven door 18 in a locked condition that is maintained during the cleaning mode of the oven 14.

The latching means 12 also includes a keeper bracket 20 into which a latch bolt 22 that is fixed to the handle 16 projects (FIG. 2) when the oven door 18 is placed in latched condition. The keeper bracket 20 which receives the latch bolt 22 is mounted on a frame structure (not shown) that frames the oven cavity front opening. The keeper bracket 20 projects forwardly with a bolt receiving opening 22 located over the top edge of the oven door 18. A cam surface 24 of the bolt receiving opening located at the front edge of the opening tends to tighten over door 18 against the front of the oven 14 and provide a tight seal for oven door 18.

A bell crank 26 is movable by the latch bolt 22 as it assumes a latching position, with this bellcrank pivoted at pivot 26 to the keeper bracket 20 and at pivot 28 to a draw bar 30 extending toward the rear of the oven 14. Such a locking arrangement is shown and described very specifically in U.S. Pat. No. 3,387,874 so that no further details of it will be given save for its interrelation with the switch means 10.

A lightweight sheet metal shell 32 of the locking means 12 serves as a base for carrying a number of the parts concerned with locking located at the rear of the oven 14. The shell 32 is secured to a vertical rear wall 34 of the oven spaced rearwardly from the vertical rear wall of the oven liner (not shown). The shell 32 is mounted for limited pivotal movement about a vertical axis passing approximately through vertically aligned upper and

lower fasteners

36, 36. This permits the shell to rock slightly during heating and cooling of the oven so as to compensate for thermal expansion and contraction of the range body and to prevent the forward end of the drawbar 30 from being pulled out of the unlatching path of the bolt locking the oven door during the heat cleaning cycle. As is disclosed in the aforementioned patent, the compensating arrangement for thermal expansion and contraction includes an arm 38 rigidly connected to opposite corners of the shell 32 by a pair of fasteners 40, 40 and a bar 42 connected to the outboard, upper end of the arm 38. The bar 42 is fixed at its forward end to the keeper assembly for the locking arrangement which positively locks the oven door during the heat-cleaning cycle. A rear link 44 is pivotally attached to one end of the drawbar 30 and mounted for vertical pivotal movement around a vertical axis formed by a pair of

notches

46, 46. This pivotal motion of rear link 44 occurs since it is mounted so as to be rigidly attached to a pivot link 48 which engages loosely in the pair of

notches

46, 46 so as to be generally pivotable within these notches.

Since, during operation of the locking means for the oven as described in the aforementioned patent, the rear link 44 must pivot relative to the compensating arm 38, proper mounting of the switch means 10 on the compensating arm 38 occasions engagement between the rear link 44 and a leaf spring formed switch blade 50 of the single-pole, single-throw switch means 10 during the oven-latching function. The switch blade 50 may then be utilized to either close (the species of FIG. and FIG. 9) or open (the species of FIG, 7) contacts within the circuit for the oven 14 so as to provide for an additional operative feature or features in the oven system without the use ofa large number of additional contacts on the selector switch of such an oven system.

In FIG. 5, an oven circuit means 52 can be seen which includes the features of a positively operated lock light and fan, with these elements being operated by the switch means mounted so as to be closed as described when the rear link 44 of the latching arrangement pivotally moves during its actuation to latching position. In this Figure, the oven cavity is generally denoted by the dash line rectangle 54, with only those parts which are physically located in the oven cavity and which deal with the actual heating of the oven are shown. These include a broil heater 56 which is also energized during the heat-cleaning cycle, a bake heater 58 and an auxiliary broil heater 60 which is used in conjunction with the regular broil heater 56 to obtain simultaneous broiling of the opposite faces ofa food article such as the steak or the like.

An oven selector switch means 62 can be set from an off position to obtain a selected operational cycle and is capable of providing all the necessary control functions for clean, broil, oven bake, time bake and auxiliary broil. The operation of this switch means and its relationship and the function of the cooking and cleaning cycles is clearly described in the aforementioned Pat. application 773,539 filed Nov. 5, 1968, and now U.S. Pat. No. 3,549,862 so that no additional description of the selector switch means or the operative circuits for heating and 'cleaning are now given. It should be noted, however, that the letter references in FIG. 5 refer to the same letter references in the table of FIG. 6 with the letter X denoting the active contacts for each mode of oven operation.

The lock assembly for locking the oven door will now be described in more detail. The lock assembly is'shown schematically and represented by a dash line rectangle 64 in FIG. 5. It is controlled in part by the operation of the latch handle 16 on the oven door 18. The arrangement by which the latching occurs and the condition for locking obtained for the oven is somewhat diagrammatically illustrated. A lock bar 66 (a portion of the pivot link 38) is provided in the assemblage so as to insure that after latching of the oven door, the housewife is unable to open the oven door due to a locking pin 68 assuming an interferring position with the lock bar 66. The lock bar 66 is pivoted as indicated by the solid arrow during the locking process and then the locking pin 68 which is formed by the plunger of a solenoid 70 may move when the solenoid 70 is deenergized to drop the locking pin 68 behind the pivoted lock bar 66 to thereby prevent its return movement until the oven has cooled to approximately 550 F. This portion of the description of the operation of the locking bar and locking pin may also be found in more detail in U.S. Pat. No. 3,387,874 and reference may now be had thereto for a more thorough understanding of the locking function of the electrical components of the latching arrangement. Some of the operative parts of the electrical circuitry 52 may also be better understood by reference to the following: Kastovich, Ser. No. 552,663 and now U.S. Pat. No. 3,504,161 relating to the manner in which heat is applied to the oven for a high temperature, quick-cleaning cycle; I-Ioltkamp, Ser. No. 531,858 and now U.S. Pat. No. 3,440,402 relating to the pulsing of the oven-leafing means; and Baker, U.S. Pat. No. 2,692,575 for the operation of the temperature controller.

The improvement made to that oven circuit is shown generally in the upper portion of FIG. 5 wherein it can be' seen that a lead 72 extends from neutral N to be connected to a fan motor 74 which, when energized, drives a fan (not shown) that may be utilized to provide cooling air for the oven so as to eliminate any hot surface spots from forming on the outer surface of the range during the cleaning cycle. The switch means 10, including the switch blade 50, is connected in series arrangement with the fan motor 74 and with the line L A highresistance 76 such as 50 K ohms also is connected to and extends from the switch means 10 so as to place a door lock indicating light 78 (neon) connected to it across the line I. to neutral N. A lead 80 is also connected to the switch means 10 at this location, with this lead attached to one side of a lock switch 82 of the previous circuitry. This lock switch is normally closed but opens thermostatically when the temperature in the oven 14 exceeds 550 to 600 F. Then, with the door lock indicating light 78 connected to one side of this switch and the lead 80 connected to its other side, the indicating light 78 is shunted by the lead 80 whenever the lock switch 82 is closed. This shunting occurs even with the switch means 10 closed so that no false signal is given by indicating light 78 upon latching of the door. Indicating light 78 is energized only when the oven door 18 cannot be unlocked with the locking pin 68 disposed behind the lock bar 66 and the solenoid 70 incapable of being actuated because the lock switch 82 is open.

It should be clear from the basic description of the functioning of the switch means 10 that moving of the oven door 18 to a latched position energized the switch means 10 to a closed position placing the fan motor 74 in an active, actuated condi tion so as to provide the function of air circulation for the oven 14. The lock indicating light 78 next lights when the oven reaches 550-600 F. and the lock switch 82 opens. Of course, another device, other than the fan motor 74 could be utilized to provide a different function for the oven and therefore a different functional feature for it. In any case, the oven circuitry illustrated in FIG. 5 would be provided with at least two additional operative features over the previously disclosed oven circuitry described in application 773,539 and now U.S. Pat. No. 3,549,862 and these additional features would be easily and conveniently provided without the addition of any terminals to the selector switch means 62 thereby reducing, to a great extent, the potential cost of the addition of an indicating light and circulating fan to an oven operating circuit.

In the description which follows and relates to the second and third embodiments of the invention numerals like those used in the description of the first embodiment have been used for like elements in the second and third embodiments.

In the second embodiment of the invention, a latch operated feature switch is used to control the inactivation of an electrically operated unit such as surface unit heater element 84 (FIG. 7). This limits the possibility of a flame forming at the heater element 84 when the oven is placed in the clean mode. More specifically, it is generally conventional to provide an exhaust for an oven, in the clean mode, through one of the heating elements of the stove. In order to comply with Underwriters Laboratory requirements and also to provide safety in operation such a heating element should be placed automatically in inactivated condition when exhaust gases are passing therethrough from the oven in the clean mode. Thus, any combustibles left in the oven exhaust will not burst into flame as they come through, and into contact with a hot element-such as element 84.

The circuit 52 includes a latching means 12 which servesto lock the oven doorin aposition where it cannot be unlatched during the heat cleaning cycle. The switch means is actuatedin a manner similar to the switch means 10 in the first embodiment of the invention and reference, therefore, should now be made to FIGS. 1-4 for an illustration of the exemplary operation of the switch means and its manner of mounting so that it is physically interrelated with the locking of the oven door 18 in a manner to be actuated thereby as the locking process for the door takes place. The switch means 10' of this embodiment, however, is moved to an open position rather than a closed position when the oven door 18 is moved to a latched condition. This operation, then, being being the reverse of the operation of the switch means 10 of the first embodiment.

In the second embodiment, an oven selector switch means 62 can be set from an off position to obtain a selected operational cycle of the oven system 52 and is capable of providing all the necessary control functions for the oven system for heat clean, broil, oven bake, time bake and auxiliary broil. The movable and fixed contacts of the selector switch 62 are identified by letter reference in FIG. 7 with these same letter references appearing in the Table of FIG. 8 and denoted by X" when the pair of contacts of any particular location are in electrical current carrying capacity.

As in the first embodiment of the invention, a temperature controller 86 for the oven is ofa bridge character and includes an auxiliary relay 88 in one leg having relay switch means 90 and 92 normally controlled in accordance with the operation of the temperature controller 86 and actuated simultaneously.

The oven door latching system is indicated by the dash-dot line rectangle 64 and includes a lock bar 66 and a locking pin 68 which engages behind the lock bar 66 when the oven is in the locked condition.

The source of electric power for the oven circuit 52' is a three-line source with 240 volts alternating current existing between L and L and I volts alternating current existing between neutral N and either of these other two lines so that operation of a portion of the oven circuit 52 may be at 120 volts or less alternating current and operation of the remainder of the oven circuit 52 is at 240 volts alternating current.

A temperature controller circuit 94 for the temperature controller 86 includes a secondary 96 of a transformer 98 with a pair of

leads

100 and 102 of this network providing the remainder of this circuit. In the cleaning mode of operation, the contacts A and H are closed thereby providing a continuous flow of current through the temperature controller circuit 94 which is normally set at l 1 volts because of the difference in the number of windings between the primary of the transformer 98 and the secondary 96, but, as set out before, a differing voltage value may be utilized in this circuit if desired.

An energizing circuit for the transformer 98 includes the aforementioned primary of transformer 98 connected to neutral N at one side through a lead 104 and with theopposite side of the primary of the transformer 98 connected to a lead 106 which, in turn, extends to and is an electrical connection with an interlock switch 108, controlled by the latched'or unlatched condition of the door. In one position of this switch illustrated at unlatched position), theinterlock switch 108 connects the common portion of the energizing circuit to an energizingbranch including a lead '1 10 which extends to a switch 112; this switch being denoted the first switch of selector switch means 62'. When this switch is closed it connects the X-terminal of the selector switch means 62' to the power'side L (through the contact L When the interlock switch 108 is in its lower positiontnot shown) it is connected to a holding branch which includes a lead 114 which extends to and is an electrical connection'w-ith an ambient thermostat 116 that monitors the temperature outside the oven and opens when an unsafe temperature has been reached in the atmosphere surrounding the oven due to the ovens operation or some other cause. The ambient thermostat 116, in turn, is connected to a lead 118 which extends to one side of timer switch 120. A lead'122 is connected to the opposite side of the timer switch 120 and extends to the L side of the oven circuit 52. Thus, when the relay switch means is closed, current is provided between the L side of the line and neutral N and thereby through the primary of the transformer 98 through the holding branch circuitry, just mentioned.

The timer switch is controlled by the operation of a timer motor 124 which is connected in parallel to the primary of the transformer 98 so as to be energized at any time that the transformer is energized. This timer motor functions to open the timer switch 120 after a predetermined energization time period for it when the preselected time-for an oven clean cycle has occurred.

In normal cooking operations, the temperature controller circuit 94 is energized through the primary of the transformer 98 to apply a low voltage to the upper and lower corners (as seen in FIG. 7) of the temperature controller 86 so that energization of the hot wire of the thermal relay 88 occurs providing an electrical source of energy to one of the

heating elements

56,58 or 60. In broil or clean modes the selector switch 62' also provides an electrical source of energy to a double pulse switch 126 which includes a resistance network 128. The resistance network is provided in the circuitry 52' and connected to the terminals T and S of selector 62 so that a variable wattage may be provided to the broil element through this double pulse switch, dependent upon whether the broil element 56 is being utilized for cleaning or for broiling purposes. The double pulse switch 126 provides a pulsing flow of current to the broil element 56 so that this element does not continuously have current therethrough during the broil or clean modes of oven operation.

As previously mentioned, during the normal baking operation, the temperature controller circuit 94 is energized through the transformer 98 to provide a low voltage to the upper and lower corners of the bridge network of the temperature controller 86. Flow of current in the heating element of the auxiliary relay 88 provides heat which causes the relay switches 90 and 92 to close so as to provide L and L, potential to the oven circuitry 52. Essentially, current is then provided to the bake element 58 through the L side of the circuit to L, through the terminals B and L,.

For heat-cleaning operation, the temperature controller 86 is bypassed or disabled by closure of a second switch 130 of the selector switch means 62 to complete the temperature controlled bypass circuit including the pair of leads I32 and 134 and the second switch 130. This functions to short out the bridge so that low voltage is applied directly across the thermal auxiliary element 88 so that the relay switch means 90 and 92 are maintained in a closed position.

A third switch 136 in the selector switch means 62 has a closed position only when the selector switch means is in its latched position. Closure of this switch completes the circuit from the power side L to the neutral N through the third switch means 136, a line 138 extending from the solenoid 70, a line 140 extending from the opposite termination of the coil for the solenoid 70, and a series connected thermostat operated lock switch 82 which is normally closed and opens at oven temperatures in excess of the normal cooking temperatures such as above 550 to 600 F.

A fourth switch 142 of the selector switch means 62 is closed only when the selector switch means 62' is set to its clean position. This places the L side of the line in connection with the L side through the closed contacts L S, the aforementioned double pulse switch 126, and a line 144 connecting the double pulse switch to the broil heater 36. A clean thermostat 146 is also in this circuit so as to provide an operable contact arrangement when the temperature exceeds a predetermined limit such as approximately l,050 F. to limit the upper temperature of the clean mode.

The manner in which the oven circuitry 52 is operated to carry out a heat-cleaning cycle is substantially similar to the heat-cleaning cycle of the first embodiment shown in FIGS. 5 and 6. However, heat cleaning is achieved in the second embodiment by the use ofa timed cleaning cycle, whereas, in the first embodiment, heat cleaning was achieved by obtaining a temperature peak sufficiently high to insure oxidation of the combustibles contained in the oven enclosure.

To initiate a heat cleaning cycle in the second embodiment, the selector switch means 62' is turned from an off position to a latched position closing the first, second and

third switches

112, 130 and 136 of the selector switch means 62. With the switch 112 closed, the energizing branch and the common portion of the energizing circuit is completed to energize the primary of transformer 98. Closure of the second switch 130 results in the temperature control bypass circuit being completed so that the relay switches 90 and 92 are closed, with the switch 92 being in the heating circuit which contains the broil element 56. However, no electrical energy flows to the broil element since, at this time, the fourth switch means 142 remains open. Closure ofthe third switch 136 of the selector switch means 62' results in an energization of solenoid 70 and the moving of the locking pin 68 into a prelatch upwardly disposed condition.

When the selector switch means 62 is turned from a latched to a cleaning position, deenergization of the solenoid 70 occurs and the locking pin 68 drops into locked condition. At this time, the third switch 136, the second switch 130 and the fourth switch 142 are all closed so that the primary of the transformer 98 remains energized through the holding branch of the energizing circuit. The temperature controllers function is takeover by the bypass circuit so that the secondary 96 of the transformer is energized and the relay switch means 90 and 92 remain closed. As a result, the oven temperature increases through the energization of the broil heater 56 until a temperature is reached at which the door lock switch 82 opens. Opening of this switch prevents reenergization of the solenoid 70 through operation of the selector switch means 62' so that the oven door cannot be unlocked. This switch will remain open until the cleaning cycle has been stopped and the oven temperature drops to the upper part of the normal cooking temperature range.

After timer motor 124 has operated for its established period, timer controller switch 120 opens to stop the heating cycle by interrupting the energization of the primary of transformer 98 which enabled relay switches 90 and 92 to remain in a closed position. Thus, a loss of power to the broil heater 56 terminates the cleaning cycle through the aegis of the relay switch means 90 and 92. The oven door 18 cannot be opened at this time because the door lock switch 82 is still open so that the solenoid 70 cannot be again energized. Once the temperature of the oven has fallen into a safe cooking range, to a temperature below that set on the door lock thermostat switch 82, the oven door 18 may be opened and the oven circuit means 52 will again be in condition for any one of the required modes of operation of the oven.

The oven control circuit 52, so far detailed. is substantially similar to the oven control circuit disclosed in the Pat. application No. 552,663 filed on Apr. 26, 1966, now US. Pat. No. 3,504,161 and owned by a common assignee although slight modifications have been made in this oven control circuit to update the system to provide more efficient operation and increase its reliability. A general understanding, however, can be obtained of the circuitry so far described, in relation to the second embodiment by reference to that application.

Normally, gases are formed during the oxidation of the combustibles in an oven so that an oven having a cleaning cycle must be provided with an exhaust to permit the exit of the gases formed within the oven during the cleaning operation. Suchan exhaust has been provided through one of the surface heating units for the oven. In order to provide safe operation, then, some means must be utilized to disable the surface unit through which the hot combustion gases are passing in order to prevent any possible flameup of any combustion gases not oxidized within the oven enclosure;

Such an arrangement is shown in FIG. 7, where, in the upper portion thereof, it can be seen that surface unit heater element 84 is connected to the L side of the circuit with the switch means 10 disposed in series relationship therebetween. This switch is designed to open when the latching system for the oven is moved to a latch condition by the movement of the aforesaid rear link 44 (FIGS. 14) relative to the arm 38 as the rear link 44 is pivoted during the latching operation. The switch 10, specifically, may be electrically connected to the line L by a line 148 so it is energized from the same source as the third switch 136 since a convenient connection at this location within the oven circuit means 52 can be easily accomplished. By this arrangement, then, a positive lockout of the surface heating element 84 is obtained while the oven circuit means 52' is in a clean mode. The surface heating element at its other side is, of course, connected to the L side of the potential by a line 150.

The third embodiment of the invention is illustrated schematically in FIG. 9. A close analysis of the circuitry shown in this Figure will disclose that it is substantially similar to the circuitry illustrated in FIG. 7 save that the switch 10 and its connections to the line L and to the heating element 84 are not present. Thus, the general operation of the circuitry of FIG. 9 is similar to the operation of the circuitry of FIG. 7, with all the normal modes of bake, speed bake, boil, auxiliary broil, latch and clean being provided in the oven circuit means 52". However, in this third embodiment, a light indicating that the oven door is locked is included and the means for interrupting current flow to a surface unit are excluded.

In order to provide the oven circuit means 52" of FIG. 9, with a positively acting lock indicating light, a switch means 10 actuated in the same manner as the switch means 10 of the first embodiment and is electrically connected to the neutral N side of the oven system by a lead 148' connected to neutral N at its one side and connected at its opposite side to the switch means 10. A lead 150' extends from the opposite contact of switch 10 and is in electrical series connection with a lock indicating light 78 which serves to indicate when the oven circuit means 52" and the oven 14 is in the locked condition of operation. A lead 152 extends from the opposite side of the light 78 so as to be connected to a resistance 154 disposed between it and the L side of the circuit. The circuitry for the light 78 is completed by a lead 156 which is attached to the lead 152 and extends from it to be connected to the neutral side N of the electrical supply system. Thus, the light 78 is disposed in a parallel relationship relative to the lead 148 and between the L side of the circuit supply and the neutral N side so that activation of the switch means 10 to a closed position activates the light 78 when the door lock thermostat switch 82 is open. If the door lock switch 82 is closed then the light 78 is shunted and does not light. Thus, light 78 indicates by being lit only when the oven door 18 is locked and cannot be opened.

It should be clear from the foregoing description that the three embodiments of the invention disclosed provide all the advantages originally set out and that these advantages accrue without the use of a more complicated selector switch means and, further, it should be clear that additional features could be provided to the oven circuit by the provision of additional latch operable switches and thereby no requisite recourse to the use of a selector switch means having a larger number of terminals than normally employed.

We claim:

1. in an oven having separate cooking and heat-cleaning modes of operation:

an oven cavity having a door therefor;

latching means for said door having opposite latched an unlatched positions;

means movable in accordance with said latching means to one position and another position;

a locked door indicating light;

a normally open, single-pole, single-throw switch controlled by said movable means;

a lock indicating circuit including said normally open, single-pole, single-throw switch and said locked door indicating light in series;

a locking circuit including a circuit-interrupting switch operable to an open position in response to oven temperature exceeding those oven temperatures experienced in a normal cooking mode;

said locking circuit and said locking indicating circuit being connected with said circuit-interrupting switch in parallel with said indicator light to provide a shunt around said light until said circuit-interrupting switch opens in response to oven temperatures; and

said indicating light being energized upon opening of said circuit-interrupting switch and after closure of said normally open, single-pole, single-throw switch by said movable means.

2. The oven according to claim 1 wherein:

said normally open single-pole, single-throw switch operates solely to control energization of said locked door indicating light;

said oven being capable of operating in said heat cleaning mode completely independent of operation of said normally open, single-pole, singlethrow switch.

3. In an oven having separate cooking and heat-cleaning modes of operation:

an oven cavity having a door therefor;

latching means for said door having opposite latched and unlatched positions;

means directly driven by said latching means so as to be simultaneously movable in accordance with said latching means to one position and another position;

a normally closed single-pole, single-throw switch controlled by said movable means;

said single-pole, single-throw switch being opened by said movable means when said latching means is moved to latched position;

a surface heating unit;

said surface heating unit being disposed in series relationship with said single-pole, single-throw switch;

whereby electrical flow to said surface heating unit is interruptable by said switch for providing a relatively cool location for exhaust of combustibles from said oven during said heat-cleaning mode.

4. The oven according to claim 3 wherein:

said normally closed, single-pole, single-throw switch operates solely to control said surface heating unit;

said oven being capable of operating in said heat cleaning mode completely independent of operation of said normally open, single-pole, single-throw switch. I

5. in an oven having separate cooking and heat cleaning modes of operation:

an oven cavity having a door therefor;

latching means for said door having opposite latched and unlatched positions;

a locked door indicating light;

a lock indicating circuit including a circuit-interrupting switch and said locked door indicating light;

a locking circuit including said circuit-interrupting switch operable to an open position in response to oven temperature exceeding those oven temperatures experienced in a normal cooking mode;

said locking circuit and said lock-indicating circuit being connected with said circuit-interrupting switch in parallel with said indicator light to provide a shunt around said light until said circuit-interrupting switch opens in response to oven temperatures;

said normally open, single-pole, single-throw switch in closed condition controlling the operation of a fan means for said oven; and

said normally open, single-pole, single-throw switch and said fan means being disposed in series in a circuit parallel to said circuit-interrupting switch and said locked doorindicating light.

6. The oven according to claim 5 wherein:

said normally open, single-pole, single-throw switch operates solely to control said fan means;

said oven being capable of operating in said heat cleaning mode completely independent of operation of said normally open, single-pole, single-throw switch.

Claims

1. In an oven having separate cooking and heat-cleaning modes of operation: an oven cavity having a door therefor; latching means for said door having opposite latched and unlatched positions; means movable in accordance with said latching means to one position and another position; a locked door indicating light; a normally open, single-pole, single-throw switch controlled by said movable means; a lock indicating circuit including said normally open, singlepole, single-throw switch and said locked door indicating light in series; a locking circuit including a circuit-interrupting switch operable to an open position in response to oven temperature exceeding those oven temperatures experienced in a normal cooking mode; said locking circuit and said locking indicating circuit being connected with said circuit-interrupting switch in parallel with said indicator light to provide a shunt around said light until said circuit-interrupting switch opens in response to oven temperatures; and said indicating light being energized upon opening of said circuit-interrupting switch and after closure of said normally open, single-pole, single-throw switch by said movable means.

2. The oven according to claim 1 wherein: said normally open single-pole, single-throw switch operates solely to control energization of said locked door indicating light; said oven being capable of operating in said heat cleaning mode completely independent of operation of said normally open, single-pole, single-throw switch.

3. In an oven having separate cooking and heat-cleaning modes of operation: an oven cavity having a door therefor; latching means for said door having opposite latched and unlatched positions; means directly driven by said latching means so as to be simultaneously movable in accordance with said latching means to one position and another position; a normally closed single-pole, single-throw switch controlled by said movable means; said single-pole, single-throw switch being opened by said movable means when said latching means is moved to latched position; a surface heating unit; said surface heating unit being disposed in series relationship with said single-pole, single-throw switch; whereby electrical flow to said surface heating unit is interruptable by said switch for providing a relatively cool location for exhaust of combustibles from said oven during said heat-cleaning mode.

4. The oven according to claim 3 wherein: said normally closed, single-pole, single-throw switch operates solely to control said surface heating unit; said oven being capable of operating in said heat cleaning mode completely independent of operation of said normally open, single-pole, single-throw switch.

5. In an oven having separate cooking and heat cleaning modes of operation: an oven cavity having a door therefor; latching means for said door having opposite latched and unlatched positions; means movable in accordance with said latching means to one position and another position; a locked door indicating light; a normally open, single-pole, single-throw switch controlled by said movable means; a lock indicating circuit including a circuit-interrupting switch and said locked door indicating light; a locking circuit including said circuit-interrupting switch operable to an open position in response to oven temperature exceeding those oven temperatures experienced in a normal cooking mode; said locking circuit and said lock-indicating circuit being connected with said circuit-interrupting switch in parallel with said indicator light to provide a shunt around said light until said circuit-interrupting switch opens in response to oven temperatures; said normally open, single-pole, single-throw switch in closed condition controlling the operation of a fan means for said oven; and said normally open, single-pole, single-throw switch and said fan means being disposed in series in a circuit parallel to said circuit-interrupting switch and said locked door-indicating light.

6. The oven according to claim 5 wherein: said normally open, single-pole, single-throw switch operates solely to control said fan means; said oven being capable of operating in said heat cleaning mode completely independent of operation of said normally open, single-pole, single-throw switch.