US2924683A

US2924683A - Magnetic switch

Info

Publication number: US2924683A
Application number: US790266A
Authority: US
Inventors: Harry G Sells
Original assignee: VERN E DAVIS
Current assignee: VERN E DAVIS
Priority date: 1959-01-30
Filing date: 1959-01-30
Publication date: 1960-02-09
Anticipated expiration: 1977-02-09

Description

Feb. 9, 1960 FlGl 4 H. G. SELLS 2,924,683

MAGNETIC SWITCH Filed Jan. 30, 1959 INVENTOR; HARRY G. SELLS ATTOR N EY United States Patent i MAGNETIC SWITCH Harry G. Sells, Columbus, Ohio, assignor of one-half to Vern E. Davis, Columbus, Ohio Application January 30, 1959, Serial No. 790,266

11 Claims. (Cl. 200-87) This invention relates to an electrical switch and more particularly to a magnetic switch of the type provided with an overload protection device.

In general, the novel switch of this invention includes a pair of movable contacts for selectively applying a source of electrical energy to an external circuit. The movable contacts are carried by an armature which is selectively disposed in one of two positions by a manually operated actuator and is retained in the selected position by a permanent magnet.

An overload protection device is electrically connected in series with the load circuit and is adapted to break the electrical connection in the event an overload or short circuit occurs in the load circuit.

This unique switch is actuated with a minimum of effort and is silent during said actuation. The switch can be compactly constructed, and its component parts are relatively inexpensive to manufacture. As such, the space requirement for its installation is insignificant and its initial cost for such installation is relatively small. The switch is readily adaptable to various volt-ampere ratings without difiiculty and thus is adaptable for industrial as well as domestic use.

It is therefore an object of the present invention to provide an electrical switch utilizing a permanent magnet to selectively retain the contacts of the switch in the selected position.

It is another object of the present invention to provide an electrical switch of the novel type described herein with an overload protection device electromechanically connected to the movable contacts of the switch whereby same breaks the electrical connection to the load circuit in the event a short develops therein.

It is a further object of the present invention to provide an electrical switch utilizing a novel arrangement of a permanent magnet, an overload protective coil, and

connecting elements in such a manner that a load circuit controlled by said switch is amply protected against overload conditions at all times.

It is still another object of the present invention to provide an electrical switch of the novel type as described herein which switch is compact, silent and efficient in operation, inexpensive to manufacture, and actuated with a minimum of effort.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of embodiment of the invention is clearly shown.

In the drawings:

Figure 1 is a partial view of the novel switch of the present invention with the actuator means removed therefrom for purposes of clarity;

Figure 2 is a sectional side view of the instant invention taken substantially along the line 22 of Figure 1;

Figure 3 is a sectional end view of the instant invention taken substantially along the line 3-3 of Figure 1;

Figure 4 is a schematic diagram of the instant invention and shows a typical connection to an external electrical circuit; and

Figure 5 is a perspective view of the novel switch of the present invention as adapted for concealed installation in a typical wall, or the like.

Relating in detail to the drawings, the switch of the present invention includes a casing means indicated generally at 20, preferably formed of dielectric material throughout. Casing supports actuator means which includes in general a push button assembly indicated generally at 21 and an armature assembly indicated generally at 22.

Armature assembly includes a dielectric bar 23 pivotally supported to the casing on a pin 24. A strip of ferrous material 25 is fastened to the bottom of dielectric bar 23 such that a permanent magnet 26 mounted to the bottom 27 of the casing will hold the right end of armature assembly downwardly when it is placed in such position by closing the right side 30 of switch 31. When the right side of switch 31 is pushed the switch pivots about a center 32 whereby metal strip 33 engages contact carrier 35 and pushes the right end of the armature assembly downwardly to cause contact between rnoveable contact 36 and stationary contact 37.

An electromagnet indicated generally at 38 is mounted to the interior of casing 20 and includes a winding 39 surrounding a magnetizable core 40.

A switch disengaging means is formed by a moveable element 42 pivotally mounted at 43. Pivoted element 42 is formed of ferrous material so as to be attracted by core 40 when an electric current, of predetermined value, passes through winding 39 of the electromagnetic means 38. Pivoted element 42 carries an upper finger 45 and a lower finger 46 which engage dielectric bar 23 for moving same upwardly when magnetic means 38 is energized.

Reference is next made to Figs. 1 and 4 for purposes of describing the circuitry of the present apparatus. A wire 50 connects a load terminal 51 with one side of winding 39 and the other side of winding 51 is connected to a source terminal 53 via wire 55, connection 56, conductor strip 57, a lower contact 58, an upper contact 59, conductor strip 68, upper contact 36, lower contact 37, metallic conductor strip 38, and source terminal 53.

As seen in Fig. 4, a load is connected at one side to terminal 51 by a wire 61 and on the other side to a source terminal 62 via a wire 63.

In operation, when the right side 30 of push button 21 is depressed, metallic strip 33 engages metallic strip 35 whereby armature assembly 22 is moved downwardly to cause engagement between

contacts

36 and 37 and

contacts

53 and 59. This connects load 60 with source terminal 53 via conductor strip 38,

contacts

36 and 37, conductor strip 68,

contacts

58 and 59, conductor strip 57, connection 56, wire 55, winding 39, wire 50, and load terminal 51, Fig. 3, and wire 61, Fig. 4, to load 60.

When an overload occurs at load 60, the current in winding 39 will reach a predetermined value at which the magnetic field through core 40 becomes great enough to urge pivot element 42 to the left as viewed in Fig. 2. It will be understood that the field strength in core 40 must be great enough to move element 42 to the left and armature assembly 22 upwardly in opposition to the downwardly directed force exerted by permanent magnet 26.

When a right end of armature assembly 22 is moved upwardly, in response to an overload at load 60 as described above,

points

36 and 37 and 58 and 59 will be opened whereby load 60 is disconnected from source terminal 53.

When the overload has been eliminated the switch can again be actuated by depressing the right side of Patented Feb. 9, 1960.

push button 21. The

contacts

36 and 37 and 58 and 59 can, of course, at any time be manually opened by depressing the left side 70 of push button 21.

I claim: v I

1. A switch comprising, in combination, casing means formed of insulating material; a permanent magnet carried by said casing means; armature means pivotally mounted to said casing intermediate a first end movable toward and away from said magnet and a second end movable toward and away from said magnet; an actuator pivotally mounted to said casing and including a first end engageable with said first end of said armature for moving said first end towards said magnet and a second end engageable with said second end of said armature for moving said second end towards said magnet; and a pair of contacts one being stationarily mounted to said casing means and the other being mounted to said armature means at a location spaced from said pivotal mounting and insulated therefrom for movement therewith relative to said one contact.

2. A switch comprising, in combination, casing means; armature means carried by said casing means and movable between a first position and second position, said armature means including a moveable contact; actuator means movably carried by said casing for selectively moving said armature means between said first and second positions; a stationary contact carried by said casing means for engagement by said moveable contact when said armature means is in one of said first and second positions; holding means for retaining said contacts in engagement; a source terminal on said casing means for connection with the potential side of a source of electrical energy; a load terminal carried by said casing means; a magnetizable core; a Winding surrounding said magnetizable core and connected at one end to said moveable contact and at another end to said load terminal; and a moveable element operatively associated with said holding means to disengage said contacts, said moveable element being actuated by an electric field induced in said magnetizable core when an electric current passing through said winding exceeds a predetermined value.

3. A switch comprising, in combination, casing means; armature means carried by said casing means and movable between a first position and second position, said armature means including a moveable contact; actuator means movably carried by said casing for selectively moving said armature means between said first and second positions; a stationary contact carried by said casing means for engagement by said moveable contact when said armature means is in one of said first and second positions; a permanent magnet for holding said armature means in a position where said contacts are in engagement; a source terminal on said casing means for connection with the potential side of a source of electrical energy; a load terminal carried by said casing means; a magnetizable core; a winding surrounding said magnetizable core and connected at one end to said moveable contact and at another end to said load terminal; and a moveable .element operatively associated with said holding means to disengage said contacts, said moveable element being actuated by an electric field induced in said magnetizable core when an electric current passing through said winding exceeds a predetermined value.

4. The switch defined in claim 2 wherein said armature means including a pivotal connection with said casing means and said actuator includes a pivoted lever having a first arm engageable with said armature means on one side of said pivotal connection and a second arm engageable with said armature means on the other side of said pivotal connection.

5. The switch of claim 2 wherein said moveable element is formed by an arm pivoted to said casing and extended to a position adjacent said core, said arm including a connection with said actuator means for moving said contacts to an open position.

6. The switch of claim 3 wherein said moveable element is formed by an arm pivoted to said casing and extended to a position adjacent said core, said arm including a connection with said armature for moving said armature away from said position.

7. The switch defined in claim 1 wherein certain of said first and second ends are formed by resilient metal said movable element being actuated by an electric fieldstrip means.

8. The switch defined in claim 1 wherein said first and second ends of said armature are formed by resilient strip means and said first and second ends of said actuator are formed by resilient metal strip means.

9. A switch comprising, in combination, casing means formed of insulating'rnaterial; a permanent magnet carried by said casing means; armature means pivotally mounted to said casing intermediate a first end movable toward and away from said magnet and a second end movable toward and away from said magnet; an actuator pivotally mounted to said casing and including a first end engageable with said first end of said armature for moving said first end toward said magnet and a second end engageable with said second end of said armature for moving said second end toward said magnet; a pair rounding said magnetizable core and connected at one end to said movable contact and at another end to said load terminal; and a movable element operatively associated with said holding means to disengage said contacts,

said first and second ends are formed by resilient metal strip means.

11. The switch defined in claim 9 wherein said first and second ends of said armature are formed by resilientstrip means and said first and second ends of said actuator are formed by resilient metal strip means.

References Cited in the file of this patent UNITED STATES PATENTS 2,337,001 Ray Dec. 14, 1943- 2,646,478 Euler et a1. July 21, 1953 2,665,344 Zozulin et al. Ian. 5, 1954 mi A He-