Description:
BACKGROUND AND SUMMARY
The switch of our invention is designed to fit in the conventional wall receptacle of a house and therefore may be easily connected to control energization of an outside light, such as a porch light. Thus, the light may be used in conventional manner or may be made to blink to identify the house for emergency purposes or the like.
Thus, in case of an emergency at home, for example, a person would telephone the proper agency to give the location of the house, and then turn the wall switch to cause the porch light to blink, so that firemen or policemen responding to the call will quickly locate the house. This emergency signal is especially valuable at night when house numbers are difficult to read.
DESCRIPTION OF THE DRAWINGS
In the drawings accompanying this description and forming a part of this specification, there are shown, for purpose of illustration, embodiments which our invention may assume, and in these drawings:
FIG. 1 is a side view of a switch illustrating an embodiment of our invention, the front and back parts of the switch being slightly separated,
FIG. 2 is a view looking into the rear of the cover of the switch, as suggested by the line 2--2 of FIG. 1,
FIGS. 3 and 4 are side views of the switch, corresponding to the line 3--3 of FIG. 2, with the back omitted, these views showing switch parts in various positions,
FIG. 5 is a side view of the switch corresponding to the line 5--5 of FIG. 2, with the back omitted,
FIG. 6 is a sectional view through the switch, corresponding to the line 6--6 of FIG. 2,
FIG. 7 is a perspective view of a switch terminal,
FIG. 8 is an electrical diagram showing the switch of FIGS. 1 through 7 in an electrical circuit with a signal device, and
FIG. 9 is an electrical diagram showing another embodiment of our invention .
DESCRIPTION OF PREFERRED EMBODIMENT
The switch shown in FIGS. 1 through 7 is of an overall size to correspond closely to the size of a conventional wall switch, and the disclosed embodiment utilizes parts of a switch presently made and sold.
The switch comprises a back 10 and cover 11, both molded to desired shape from a suitable plastic material, and connected in well known manner by screws or rivets (not shown). A metal plate 12 is provided to secure the switch in a wall receptacle in conventional manner.
The back and cover have matching recesses 14--14 for receiving the flat sides 15 of terminals. As seen in FIG. 2, a first set of terminals A and B is disposed at one side of the switch, and a second set of terminals C and D is disposed at the other side of the switch. Each terminal has a side 16 (see FIG. 7) at right angles to the flat side 15, and a contact or switch arm is adapted to be carried by the side 16. A screw 17 is threaded through the terminal side 15 to provide for connection of a conductor wire in usual manner.
In the embodiment disclosed in FIGS. 1 through 7, a first switch arm 18 has one end fixed to terminal A and has a contact 19 extending from opposite sides at the free end of the arm. The arm is formed of spring metal and shaped to the form shown in FIGS. 1, 3 and 4, so that its center part 20 is engageable with a cam 21 on an actuator 22.
The actuator is molded of plastic material and provides a finger piece 23 exteriorly of the switch and a detent-carrying piece 24 interiorly of the switch. Trunnions 25 extend from opposite sides of the actuator and fit within matching recesses in the back and cover 10, 11 to provide a pivot. As best seen in FIG. 6, the actuator piece 24 carries a spring-pressed ball detent 25 which releasably fits within any one of three recesses 26 in a part 27 extending inwardly of the back 10.
The contact 19 on switch arm 18 is adapted to electrically engage either one of two contacts 28,29. The contact 28 is fixed to terminal B while the contact 29 is fixed to the back 10. A conductor 30 electrically connects contact 29 to a contact 31 which is adapted to electrically engage terminal D.
Fixed to terminal D is one end of a bi-metallic arm 32 (see especially FIG. 5) and the free end of the arm carries a contact 33 which is normally spaced from a contact 34 carried by the terminal C. A resistance wire 35 is wound around the bi-metallic arm 32 and has its opposite ends respectively connected to terminals C and D.
In the centered position of the actuator 22, as seen in FIGS. 3 and 6, the cam 21 has moved the switch arm 18 so that its contact 19 is out of engagement with either contact 28 or 29. In the lower position of the actuator 22, the contact 19 on switch arm 18 is in engagement with the contact 28, as seen in FIG. 1. In the upper position of the actuator 22, the cam 21 has moved the switch arm 18 so that its contact 19 is spaced from the contact 28 and in engagement with the contact 29, as seen in FIG. 4.
The switch is shown in an electrical circuit in FIG. 8 which comprises conductors 40, 41 which may be connected to the household power supply. Conductor 40 is connected to terminal A and conductor 41 is connected to one side of a signal device 42 which may be an electric bulb, or a device which gives an audible signal when energized. The other side of the signal device 42 is connected to terminals B and C through a conductor 43.
When the actuator 22 is on the middle position shown in FIGS. 3 and 6, there will be no current flow to the signal device. In the lower position of the actuator 22, as seen in FIG. 1, the circuit is completed from line conductor 40, terminal A, switch arm 18, closed contacts 19 and 28, terminal B, conductor 43, signal device 42 to line conductor 41, and the signal device will be energized in steady manner.
When the actuator 22 is in its upper position shown in FIG. 4, contacts 19, 28 will be disengaged and contacts 19 and 29 closed. The circuit is thus completed from line conductor 40, terminal A, switch arm 18, contacts 19 and 29, conductor 30, contact 31, terminal D, resistance wire 35, terminal C, conductor 43, signal device 42 to line conductor 41. However, resistance conductor 35 absorbs most of the current to generate heat, and an insufficient amount passes to signal device 42 so that the latter does not give a signal.
The heat of the resistance wire 35 affects the bi-metallic arm 32 and causes it to bend to close contacts 33,34, whereupon the resistance wire is shorted out since the current will more readily flow through the bi-metallic arm 32 and thus a full amount of current will flow to the signal device 42 to activate it.
However, when the resistance wire 35 is shorted out, it will no longer heat the bi-metallic arm 32 and the latter will cool and tend to return to its shape shown in FIG. 5, whereupon the contacts 33,34 are disengaged so that current will again flow through the resistance wire 35 to cause it to generate heat. This action will continue so that the signal device is intermittently actuated to generate the signal, such as a flashing light when an electric bulb is used.
DESCRIPTION OF OTHER EMBODIMENT
FIG. 9 schematically discloses a modified switch 50 in an electrical circuit of the type heretofore described. A switch blade 51 is pivoted to the housing of the switch at 52 so that it may swing to electrical contact with either terminal 53 (as shown in full line) or terminal 54 (as shown in dotted line). The switch blade also has a center position, shown in dot-dash line.
A fixed contact 55 is electrically connected to the terminal 54. Also, one end of a bi-metallic arm 56 is fixed to the terminal 54, the free end of the arm carrying a contact 57. A resistance wire 58 is wound about the arm 56 and has its opposite ends connected respectively to the terminal 54 and contact 57.
When the switch blade 51 is in its full line position, the circuit is completed from line conductor 59, through blade 51, terminal 53, conductor 60, signal device 61 and to line conductor 62, and the device will be energized in steady manner.
When the switch blade 51 is in its dotted line position, the circuit is completed from line conductor 59, through blade 51, terminal 54, resistance wire 56, conductor 60, signal device 61 to line conductor 62. However, the resistance wire will use most of the current to generate heat, and the signal device will not be energized. The generated heat will cause the bi-metallic arm 56 to bend and close contacts 55, 57 to short out the wire 58 and energize the signal device. Thereupon, the bi-metallic arm will cool and break the contacts 55,57, and this action will be repeated to intermittently energize the signal device.