US2273751A - Electric switch with time control mechanism - Google Patents

Description

1942- w. F. EDWARDS ET AL 2,273,751

ELECTRIC SWITCH WITH TIME CONTROL MECHANISM Filed Jan. '7, 1939 2 Sheets-Sheet l Illll INVENTOR WILLIAM F. EDWARDS JOHANNES R. CARLSON BY THEIR ATTORNEYS Feb. 17, 1942.

w. F. EDWARDS ET AL ELECTRIC SWITCH WITH TIME CONTROL MECHANISM Filed Jan. 7, 1959 2 Sheets-Sheet 2 WILLIAM F. EDWARDS JOHANNES R. CARLSON BY THEIR ATTORNEYS time interval.

Patented Feb. 17, 1942 'UNITED STATES PATENT OFFICE ELECTRIC SWITCH WITH TIME CONTROL MECHANISM William F. Edwards, West Hartford, and Johannes R. Carlson, Hartford, Conn., assignors to The Arrow-Hart & Hegeman Electric Company, Hartford, Conn., a corporation of Connecticut Application January 7, 1939, Serial No. 249,814

8 Claims.

This invention relates to electric switches for controlling plural circuit arrangements such as for example in electric ranges and the like. More particularly the invention relates to a switch for multiple circuit control which is provided with means to automatically change the circuit connections after the passage of a predetermined It is an object of our invention to provide a multiposition rotary electric switch for controlling multiple electric circuits which will be capable of changing the circuit connections after a selected time interval, and which may be manually moved at any time to any one of a plurality of circuit-making positions. 7

Another object of our invention is to provide a cam-operated type of rotary switch for use with electric range circuits and the like which may be operated by a time control mechanism after a selected time interval and which permits quick separation of the electric contacts at the instantof circuit interruption. I

Another object of our invention is to provide a switch of the above type which may have the time control mechanism assembled therein as a separate unit.

Other objects and advantages of our invention will become apparent as the invention is described in connection with the accompanying drawings.

In the drawings:

Figure 1 is a plan view of an electric switch embodying the principles of our invention;

Figure 2 is an elevation view partly in vertical section of the switch in Figure 1;

Figure 3 is a fragmentary detail view of the connection between the switch spindle and the time control mechanism of the invention;

Figure 4 is a view looking into the bottom 01 the switch in Figure l with the time control mechanism removed;

Figure 5 is a plan view of the time control,

mechanism as removed from the switch ure 4;

Figure 6 is a view similar to Figure 4, but with the parts in the position they occupy when the switch is set for a -minute time interval;

in Fig-' Figure 7 is a view similar to Figure 5, but withthe time mechanism Figure 6;

Figure 8 is'a fragmentary detail view showing in plan one of the line terminals and its asso ciated switch contacts and their cooperation with the operating cam switch spindle.

in position corresponding to Figure 9 illustrates in plan another of the line terminals and its associated movable contact.

Referring to the drawings, the switch comprises a two-part casing of molded insulatingmaterial in which the switch parts are housed Preferably, the casing will have plane side and top walls and will have the operating parts mounted upon the base 2 over which the hollow, cup-like" cover I fits to enclose and protect the switch parts. Conveniently, the base 2 may be hollowed out from the bottom to receive a clockwork mechanism 10 as hereinafter described.

The switch is operated by a dial handle 3 afiixed upon a spindle l which extends through the cover I and has 'mounted thereon four cams, such as and 25. These cams are loosely mounted upon but are required to move with the switch spindle by mounting means of the type described in the copending application of Louis A. Yeske, Serial No. 140,705, entitled Rotary switch, now Patent 2,182,715, dated December 5, 1939. But the present construction differs from the Yeske invention in the respect that the cams are permitted lost motion relative to the spindle. Briefly, the movement of the cams with the spindle is compelled by the engagement therewith of a member 6 which is keyed to and moves as a unit with the spindle 4 and has arms 6a extending parallel to the spindle through apertures, for example 35a, in the cams. Preferably, the apertures are larger than the cross section of the member Ba, so that the cams are permitted a small amount of movement rela tive to the spindle and-the operating member 6 for a purpose to be hereinafter more fully described. The cams may be spaced by washers, for example 36, 38, afiixed to the spindle. If desired the cams and their securing member and spacing washers may be secured in assembled position by peaning over the ends of the securing member under the bottom cam, or they may be secured by a separate anchor disc keyed to the spindle below the bottom cam as in the Yeske invention.

The switch is provided with three line terminals I0, 20, and 30 which have attached to upstanding arms thereof similar spring contact fingers each of which has on its free end a contact button, that is, spring fingers 32 and 33 are mounted upon arms bent up from the sides of the terminal 30 and have contact buttons 3| and 34 mounted on their free ends, respectively. In like manner, the spring finger I l is mounted upon an upstanding arm (not visible) of the terminal I0 and has a contact button l2 while spring like manner, the movable contact button ll engages and disengages the stationary contact 42 and the movable contact button 2| engages and disengages the fixed contact 5| as their respective cams (not visible) are rotated by the switch spindle. In view of the complete disclosure of this type of cam-and-spring switch mechanism in the previously mentioned application of Louis A. Yeske, a further illustrationand descriptionof this mechanism will not be necessary. It will be understood by those skilled in the art that by making appropriate wire connections between the line and load terminals and a suitable resistance unit, various degrees-of heat, such as high, medium and low heats, may be obtained as the switch is manipulated. It will be understood, however, that the switch is not limited to use with a resistance unit.

For the purpose of controlling the movement of the switch spindle and movable contacts a conventional time control mechanism or clockwork designated generally by the numeral may be secured in the bottom of the switch casing. The clockwork of this mechanism may be of any suitable type or construction, it only being necessary to have the clock mechanism proportioned so as to rotate its main arbor 12 the required amount within a specified period so as to impart a sufficient rotation to the switch spindle 4 to cause operation of the switch contacts at the end of the predetermined interval as hereinafter described.

In order that the motion of the clock mechanism may be imparted to the switch spindle 4 and in order that the manual movement of the switch spindle may be imparted to the clock mechanism for the purpose of winding the same, a disc 13 with a notch 14 therein may be mounted upon an end of the clock arbor 12 which extends toward the switch mechanism and is coaxial with the switch spindle. For engaging with the disc 13 a disc 8|] may be rigidly attached to the end of the switch spindle adjacent the disc 13 and may have a projection 8| extending from the face of the disc parallel to the spindle 4 in position to engage in the notch I4, so that the switch spindle 4 and the clock arbor 12 will move as a unit. Preferably, the clock mechanism will be of the type in which rotation of the arbor in one direction will wind the clock spring and set the mechanism for a predetermined period, and which will permit the reversal of the arbor to unwind the spring and nullify or vary the previous setting, when it is desired to do so manually.

To this end a spring clutch disc 90 may be fixed for movement with th clock arbor and may press upon a driving gear 92 of the clock mechanism in conventional fashion so as to move with the gear as the clock mechanism unwinds normally. When the handle is reversed, manually, to nullify a previous clock setting, the disc 90 will slip on the face of the gear 92.

In order that the switch contacts may be held in their various positions, a radial projection 82 is provided upon the disc 80, which projection engages with an indexing spring 84 which may casing extending into the countersunk recess 89. When the switch is in medium position the projection 82 will have moved about 45 counter clockwise from the Figure 4 position, to engage in the indentation 86; and when the switch is in the low position the projection 82 will have moved about 45 more in counter-clockwise direction. In that position the clockwork which is under a slight initial tension will hold the projection 82 as against the shoulder 81. Movement of the switch about 135 counter-clockwise from Figure 4 will place it in high heat position. While in high position it will be at all times under the effort of the clock mechanism and will remain in the high heat position only so long as the time interval at which the clock mechanism has been set has not elapsed.

As previously described, the operating member 6 loosely engages the operating cams by reason of the large size apertures 3511, thereby providing lost motion between the operating cams and the member 6. This lost motion permits the pressure of the contact springs, as the cam engaging port-ions (320 for example) start to move down into the depressed parts 35d of the cam, to move the cams relatively to their operator 6.

Thus. the contact springs may snap the contact buttons which they carry away from the corresponding stationary contact buttons as the switch is moved automatically into low heat position by the clock mechanism. If this lost motion means were not provided the separation of the contacts automatically would be very slow and would be accompanied by considerable arcmg.

In operation the switch may be moved manually into any position by rotation of the dial handle 3. It will remain in either off, medium or low positions permanently, that is, until manually moved into another position. The indexing spring prevents the clock mechanism from moving the switch from any of those positions. But, on movement into high heat position, the handle is turned until the pointer (Figure 1) indicates the time interval that it is desired to have the switch remain in high heat position. When such interval elapses the operating cams will move into low position. Just as they do so, the lost motion between them and their operator 6 will allow the contacts and cams to move independently of the operator 6 so as to permit the contacts to snap into their low position.

If it is desired to change the setting of the switch after it has once been set for a certain time interval this may be done by manipulating the handle, which will either wind the clock further or unwind it, depending on the direction in which the handle is turned.

From the foregoing, it will be seen that we have provided a novel construction of switch mechanism which is particularly adapted for use in rotary heater switches for the purpose of controlling automatically the movement of the switch from high heat or other position into a low heat'or other position when the time interval for which the switch has been set has elapsed. Also our invention may be assembled in a simple and expeditious manner by incorporating the clock mechanism in the combination after the switch itself has been fully assembled. By reason of our construction, repair, replacement or cleaning of the clock mechanism may be easily and quickly accomplished, or switch parts may be replaced without disassembling the parts which make up the clock mechanism. We have also provided means for permitting the contacts to snap into low heat position as the end of the interval of high heat is reached.

Obviously the terms high, medium and low heat positions are simply relative and are used for convenience in designating different positions of a switch which is adaptable generally to multiple circuit control.

Th inventionmay be adapted for use in moving the contacts either into or out of any desired switch position. Such adaptations and many modifications within the erating said shaft, cam means operated by said .shaft for moving said contacts into one switch scope of our invention will occur to those skilled in the art. Therefore, we do not limit the invention to the specific embodiment described.

1. In a manually and automatically operable switch, a plurality of separable switch contacts connectible in at least two different closed-circuit positions and an open-circuit position, manually rotatable means movable in both clockwise and counterclockwise directions, rotary cam means for causing engagement and disengagement of said contacts at will into all of said positions, and a lost-motion connection between said manual means and said cam means, and means settable by rotation of said manual means for moving said contacts at the end of a "selected time interval from one 'of said positions to another position with a snap action.

2. In a manually and automatically operable switch, a plurality of separable switch contacts connectible in at least two, different closed-circuit positions and an open-circuit position, manually controllable cam-operatingmeans including a lost-motion connection for causing engagement and disengagement of said contacts at will into all of said positions, and means settable to move said contacts at the end of a selected time interval from one of said positions to another position with a snap action, a separable connection between said settable means and said camoperating means whereby said settable means position from another, a lost-motion connection between said cam means and said shaft whereby contact operation occurs with a snap-action at the end of the selected time interval, and manual means for operating said shaft in both clockwise and counterclockwise directions to move said contacts into at least two closed-circuit positions and an open-circuit position at any time.

6. In a rotary switch, an operating shaft, a plurality of separable switch contacts connectible in at least two different closed-circuit positions and an open circuit position, retarded-action means settable for selected time intervals for operating said shaft, cam means operated by said shaft for moving said contacts into one switch position from another, a lost-motion connection between said cam means and said shaft whereby contact operation occurs with a snap-action at the end of the selected time interval, and manual means for operating said shaft in both clockwise and counterclockwise directions to move said contacts into at least two closed-circuit positions and an open-circuit position at any time, and to set said retarded means.

7. In a rotary switch, an operating shaft, a plurality of separable switch contacts connectible in at least two different closed-circuit positions and I an open circuit position, retarded-action means settable for selected time intervals for operating said shaft, cam means operated by said shaft for moving said contacts into one switch .ing constructed and arranged to be deenergized when said manual means is actuated in one direction to move said contacts from the position in said operating means and said contacts, and means settable to move said contacts at the end of a selected time interval from one of said positions to another position with a snap action, a separable connection between said manually operable means and said settable means whereby said settable means may be assembled and removed asa unit from the switch.

4. In a manually and automatically operable switch, a plurality of separable switch contacts connectible in at least two different closed-circuit positions and an open-circuit position, manually operatable means to cause engagement and disengagement of said contacts at will into all of said positions, and means settable to operate which the retarded'means is operating upon them.

8. In a rotary switch, a plurality of separable switch contacts connectible in at least two different closed-circuit positions and an open ciricuit position, an operating shaft, manually controllable means for operating said shaft, re-

- tarded-action means in which energy is.st0red said contacts at the end of a selected time in terval from one of said positions to another, a separable connection between said manually operable means and said settablemeans whereby said settable means may be assembled and removed as a unit from the switch. r

by rotation of said shaft, said retarded-action means being settable for selected time intervals for operating said shaft, cam means operated by said shaft for controlling contact separation and engagement, and a lost-motion connection between said cam means and said shaft whereby contact operation .occurs with a snap-action at the end of the selected time interval, and a separable connection between said retarding means and said shaft permitting assembly and removal of said retarding means as a unit inand from the switch. 1

WILLIAM F. EDWARDS. JOHANNES R. 'CARLSON.

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