US3928834A

US3928834A - Time delay switch

Info

Publication number: US3928834A
Application number: US447877A
Authority: US
Inventors: William E Soong
Original assignee: Individual
Current assignee: Individual
Priority date: 1974-03-04
Filing date: 1974-03-04
Publication date: 1975-12-23
Anticipated expiration: 1992-12-23
Also published as: JPS50119978A; CA1011787A

Abstract

A time delay switch which has three positions with one position immediately turning the switch on and a second position immediately turning the switch off and further providing for a third time delay position such that the circuit remains on for a predetermined time after the switch has been moved to the time delay position.

Description

United States Patent ng Dec. 23, 1975 TIME DELAY SWITCH Primary ExaminerR. N. Envall Jr. I I a [76] mentor $221222 g 71st St Assistant ExaminerFred E. Bell Attorney, Agent, or FirmHill, Gross, Simpson, Van Filedi 1974 Santen, Steadman, Chiara & Simpson [21] Appl. No.1 447,877

[57] ABSTRACT [52] US. Cl. 337/81; 337/88; 337/341 A time deiay SWitch Which has three positions with [51] Int. Cl. HOIH 61/00; HOlH 71/16 one position immediately turning the SWitch on and a [58] Fleld of Search 200/53; 337/81 second position immediately turning the switch off 337/36 39; 335/23 43 and further providing for a third time delay position i such that the circuit remains on for a predetermined [56] References C'ted time after the switch has been moved to the time delay UNITED STATES PATENTS position.

3,559,140 l/l97l Brown 337/81 3.569.887 3/1971 Brown 337/81 7 Chums 5 D'awmg F'gures I I II I K 24 H i 28 1 Q j t, .1" j 2/ a a; j4 22 j 47 56x 44 I /e \5/" I": o d W a 155 4 it --5 36 I 55 /4 32 US. atent Dec. 23, 1975 TIME DELAY SWITCH BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates in general to time delay switches and in particular to an improved time delay switch that can be mounted in conventional wall boxes.

2. Description of the Prior Art Time delay switches have been known which generally utilize a latching mechanism which is released by a heat responsive flexing motion of a bimetallic element thereby opening the electric circuit. Such latching mechanism is expensive and very difficult to construct; and therefore, it is unsuitable for mass production.

SUMMARY OF THE INVENTION The present invention provides a time delay switch which does not utilize a latching mechanism but em ploys a spring bias snap-action blade which can be manually actuated to open or close the electrical circuit by the actuation of an operating lever to the on or to the override off positions or alternatively, the operating lever can be placed in a time delay off position wherein the lever does not directly open the circuit but rather completes a second circuit which connects a heating coil mounted on a bimetallic strip to a source of power. Current flows through the heating coil and heats the bimetallic strip which causes it to bend and engage the snap-action blade of the main circuit so as to move it to the off position. Simultaneously, the circuit to the heating coil of the bimetallic strip will be opened. The invention utilizes no latching mechanisms; and thus, a simple and inexpensive device is provided which lends itself to mass production.

The present invention provides a time delay switch having a general overall configuration of conventional two-way switches and can be mounted in conventional wall boxes and thus can be quickly and easily installed to replace conventional standard wall box switches. A second embodiment is provided for replacing lamp switches which comprises a shell lamp holder switch with a slide lever and in one full out position the lever turns on the circuit and the other full out position turns off the circuit. If the lever is moved to a center position the circuit will be turned off with a time delay.

Other objects, features and advantages of the invention will be readily apparent from the following description of certain preferred embodiments thereof, taken in conjunction with the accompanying drawing, although variations and modifications may be effected without departing from the spirit and scope of the novel concepts of the disclosure, and in which:

BRIEF DESCRIPTION ,OF THE DRAWING DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 of the invention illustrates in perspective the time delay switch which is constructed such that it has the external configuration of standard switches such that it can be simply constructed and mounted in conventional wall boxes to replace the standardswitch. The switch 10 includes a steel mounting bracket 11 which has

openings

12 and 13 at opposite ends thereof through which mounting screws are receivable as in conventional switches. The body portion of the switch 14 is provided with a switch lever 16 that can be moved to three distinct positions. The switch lever 16 is shown in the time delay off position. It can also be moved to the full up on position or to the override off position which is full down.

A brass screw 21 is mounted on the left side of the switch relative to FIG. 1 so as to receive the hot" power line; and an associated chrome screw 20, shown in FIG. 5, is mounted on the corresponding position on the right side of the switch.

FIG. 2 is an electrical schematic view illustrating the time delay switch of the invention 10 with the screw 21 connected to the hot line 27 of the power supply and the chrome screw 20 connected to the appliance side 28. The lead 28 is connected to an appliance, as for example, a light 19 and the other side of the light is connected by conductor 31 to the other side of the power supply.

FIGS. 4 and 5 illustrate the time delay wall switch of the invention. The wall box 22 receives the switch 10 and has a cover plate 32 formed with an opening through which the switch actuating lever 16 extends. The hot line 27 of the power switch and the line 28 between the switch and the appliance are mounted in conduit 26 which has its outer shield grounded. The conduit 26 is connected by

nuts

24 and 23 to the wall box 22 and makes electrical contact therewith such that the wall box 22 is grounded. Hot line 27 is connected to screw 21, and a contact 44 is connected from screw 21 to a pivoted on pin 102 switch actuator 46 which is generally v-shaped. A snap-action switch blade 33 has one end connected to a pivot support and the other end carries a switch contact 36. An actuating arm 49 extends from the switch actuator 46 to the snap blade 33. A switch contact 37 is mounted on the switch body and is connected with conductor 38 and is engageable with contact 36 when the switch is in the on condition. Conductor 38 is connected to chrome screw 20 and to lead 28. The switch actuator 16 is pivotally supported by pivot pin 42 and has a cam portion 43 which engages the switch actuator 46. A segment of conducting material 47 is mounted on the switch lever 16 and is engageable with

brushes

41 and 48. Brush 41 is connected by conductor 39 to lead 38, and brush 48 is connected to one end of a heating winding 51 which surrounds a bimetallic strip 53 which has an engaging portion 54 for engaging the snap-action blade 33. The other end of the heating winding 51 is connected by lead 52 to the electrical conducting mounting bracket 11 and to ground through the wall box 22 and the shield 26.

In operation when switch actuator 16 is moved to the full up on position, the cam 43 moves the member 46 about the pivot and moves the snap-action blade 33 to the position where contact 36 engages contact 37 which closes the electrical switch and provides continuity between

conductors

27 and 28 through the lead 44, electrical conducting member 46, actuating arm 49, snap-action blade 33, contact 36, contact 37, and lead 38. In this condition, the appliance 19 will be illuminated. It is to be noted that in this position segment 47 does not engage the brush 41; and thus, the circuit is not completed between lead 39, and brush 48 and the heating coil 51 will not be energized.

When the switch actuator 16 is moved to the full down position, the appliance will be turned off instantly and the circuit between

leads

27 and 28 will be instantly opened. This is because the cam 43 engages the actuator 46 which causes the snap-action blade 33 to snap immediately to the open position because the arm 49 pulls contact 36 away from contact 37. It is also to be noted that in this position, the segment 47 will not engage brush 48; and thus, the circuit will not be completed through heating coil 51 as brush 48 does not engage segment 47.

If the switch is on and a time delay off is desired such that the appliance is turned off, a predetermined time delayed period after movement of the switch lever. the switch lever is moved to the horizontal solid line position illustrated in FIG. 5. When this occurs, the snapaction blade 33 maintains the

contacts

36 and 37 in engagement; and the cam 43 does not force the contacts apart since the cam portion 43 is in the intermediate position and does not drive the switch actuator 46. In this position, the segment 47 engages the

brushes

41 and 48; and the circuit through the heating coil 51 will be completed from lead 38, lead 39, brush 41, segment 47, brush 48, to one end of the heating coil. The other end of the heating coil is connected to ground through the member 11, the wall box 22, and the conduit 26. At this time with

contacts

36 and 37 engaged, contact 38 will be connected through

members

33, 49, 46, and lead 44 to hot line 27; and thus, current will flow in the heating coil 51. The heating coil 51 will heat the bimetallic strip 53 which will cause it to bend and move actuator 54 against snap-action blade 33 to cause it to snap to the position shown in FIG. thus opening

contacts

36 and 37 and breaking the continuity between

leads

27 and 28 and turning off the appliance. At the same time, power to the heating coil 51 will be disconnected because the heating current to the coil 51 passes through the

contacts

36 and 37 and when these are broken, current will not pass through the heating coil.

Thus, the user of the switch of this invention can instantly turn on the appliance and instantly turn it off or alternatively can turn the appliance off with a time delay as determined by the time of actuation of the snap-action blade 33 with the bimetallic strip 53 and the heating coil 51. It is to be realized, of course, that this snap-action blade 33 has two stable positions; one where the contact 36 engages contact 37, and the other wherein the

contacts

36 and 37 are separated. These two positions are maintained by the bias spring 60.

FIG. 3 illustrates a time delay switch, for example, for a shell lamp holder for a floor or table lamp. In this embodiment, power is supplied from a plug 73 to conductors 74 and 76 and conductor 74 is connected to pivoted on pin 101 actuator 77 which is connected by arm 78 to the snap contact member 79. One end of the snap contact member 79 is mounted on a pivot with a bias spring 99 mounted in support 81 and the other end carries a contact 82 which is engageable with a contact 83. Contact 83 is connected to lead 63 which connects to the appliance, as for example, the light bulb 61. Power line 76 is connected to the other side of the light bulb 62 and to a brush 72 which engages a circular conductive segment 69 mounted on a switch actuating lever 75. A brush 71 is engageable with segment 69 and is connected to lead 84 which has its opposite end connected to a heating coil 85 which is wound around bimetallic strip 86supported in bracket 90 at one end and formed with an actuating member 87 at the other end for engaging the snap action member 79. When the end 67 of the actuator 75 is pushed in to the full in position, the actuator 68 will cause the member 77 to close the snap-action member 79 through the member 78 and contact 82 will engage contact 83 and circuit to the lamp 61 will be completed through the

members

77, 78, 79,

contacts

82, 83, lead 63. The

structural members

64 and 66 are provided with suitable guide openings for the actuator 75. When the actuator 75 is pushed on the end 65 to the full left position, the member 68 will engage the member 77 and will open the snap-action blade 79 through the member 78 thus moving contact 82 out of engagement with contact 83 and opening the circuit to the lamp 61.

If a delayed action in the opening of the circuit is desired the actuator 75 is moved to an intermediate position such that the member 68 does not move the member 77 the snap blade 79 will stay in the closed position with contacts 82 engaging contacts 83. However, in this position, the conductive segment 69 will engage the

brushes

71 and 72 and power will be applied to the heating coil to the lead 84 and through

contacts

82 and 83. After a predetermined time, the heating coil 85 will heat the bimetallic member 86 causing it to deflect in a direction such that actuator 87 engages the snap-action member 79 to open

contacts

82 and 83. When these contacts open, power to the lamp 61 is disconnected as well as power to the heating coil 85.

It is seen that the time delay switch of the present invention provides an inexpensive and simple switch device that can be manufactured so as to replace conventional switches. Although it has been described with respect to preferred embodiments, it is not to be so limited as changes and modifications may be made which are within the full intended scope as defined by the appended claims.

I claim as my invention:

1. A three position electrical switch having on, off, and time delay off positions comprising, a switch housing, a pair of power supply leads, a snap action member with two stable positions mounted in said housing, a first contact carried on said snap action member. a second contact mounted in said housing and engageable with said first contact in one of said stable positions of said snap action member and electrically connected to one of said pair of power leads, a pivotally mounted V-shaped actuating member electrically connected to the other one of said pair of power leads and mechanically coupled to said snap action member and electrically connected to said first contact, a bimetallic member mounted so that in a first position it engages said switch actuator to move it to one of said stable positions to separate said first and second contacts, heating means mounted adjacent said bimetallic memher, and a control member engageable with said actuating member to move it and said snap action member, and circuit means connected to said control member for connecting said heating means to said one of said pair of power leads when said control member does not engage said actuating member, said second side of said heating means connected to ground and said control member has a portion engageable with both legs of said V-shaped actuating member to move it either direction.

2. A three position switch according to claim 1 wherein said circuit means includes a pair of brushes respectively connected to said one of said pair of power leads and to said heating means and an electrical conductive area mounted on said control member and engageable with both of said pair of brushes when said control member is in the time delay off" position.

3. A three position switch according to claim 2 wherein said control member is pivotally mounted to 6 said housing and has a portion which extends from said housing.

4. A three position switch according to claim 3 wherein said control member has a cam portion engageable with both of said legs of said V-shaped memher.

5. A three position switch according to claim 4 wherein electrical conductive area is crescent shaped.

6. A three position switch according to claim 2 wherein said control member is slidably movable in said housing and has a projecting portion which is engagcable with both of said legs of said V-shaped memher.

7. A three position switch according to claim 3 wherein said electrical conductive area extends longitudinally of said control member.

Claims

1. A three position electrical switch having ''''on'''', ''''off'''', and ''''time delay off'''' positions comprising, a switch housing, a pair of power supply leads, a snap action member with two stable positions mounted in said housing, a first contact carried on said snap action member, a second contact mounted in said housing and engageable with said first contact in one of said stable positions of said snap action member and electrically connected to one of said pair of power leads, a pivotally mounted V-shaped actuating member electrically connected to the other one of said pair of power leads and mechanically coupled to said snap action member and electrically connected to said first contact, a bimetallic member mounted so that in a first position it engages said switch actuator to move it to one of said stable positions to separate said first and second contacts, heating means mounted adjacent said bimetallic member, and a control member engageable with said actuating member to move it and said snap action member, and circuit means connected to said control member for connecting said heating means to said one of said pair of power leads when said control member does not engage said actuating member, said second side of said heating means connected to ground and said control member has a portion engageable with both legs of said V-shaped actuating member to move it either direction.

2. A three position switch according to claim 1 wherein said circuit means includes a pair of brushes respectively connected to said one of said pair of power leads and to said heating means and an electrical conductive area mounted on said control member and engageable with both of said pair of brushes when said control member is in the ''''time delay off'''' position.

3. A three position switch according to claim 2 wherein said control member is pivotally mounted to said housing and has a portion which extends from said housing.

4. A three position switch according to claim 3 wherein said control member has a cam portion engageable with both of said legs of said V-shaped member.

6. A three position switch according to claim 2 wherein said control member is slidably movable in said housing and has a projecting portion which is engageable with both of said legs of said V-shaped member.