US1748329A - Flashing switch - Google Patents

Description

Feb. 25, l 930.

E. M. CLARK FLASHING SWITCH Filed Aug. 20, 1926 Patented Feb. 25, 1930 UNITED STATES EDWIN M. CLARK, OF CLARKSTON, MICHIGAN FLASHING SWITCH Application filed August 20, 1926. Serial No. 130,441.

This invention relates to switches, and relates particularly to switches adapted to continually make and break acircuit at short time intervals, commonly known as flashing switches.

One object of the invention is to provide a flashing switch operable by a single simple electro-magnet (or a plurality thereof) throughout any desired period of time, without requiring lubrication or other attention,

and which avoids necessity for the usual rotary motor drive mechanism, with its relatively high initial cost, upkeep expense, and liability of trouble.

Another object is to provide a flashing switch in which arcing will be minimized and pitting of contacts due to arcing completely avoided.

- Still another object is to provide in a simple manner for selectively varying the length of the time intervals during which the switch is open and closed.

A further object is to provide a mounting for the switch such as may be used to maintain it so leveled as to operate at maximum efiiciency.

These and various 1 other objects are attained by the construction hereinafter de scribed, and illustrated in the accompanying drawings, wherein: u

Figure 1 is a front view of the switch, including an electrical diagram.

Figure 2 is a side view thereof.

Figure 3 is a horizontal sectional view, taken upon the line 33 of Figure 1.

In these views the reference character 1 designates a base formed preferably of insulating material. To said base, at opposite edges thereof, a pair of metallic standards 2 0 and 2 are rigidly secured. The upper ends of said standards pivotally mount a pair of metallic hangers 3 and 3 arranged between and preferably adjacent to said standards. In

the illustrated embodiment of the invention.

5 said hangers have knife edge pivots i attached to their upper ends, which are seated in opposed bores 5 in the standards 2 and 2.

The hangers 3 and 3* at their lower ends carry a platform 6, preferably of insulating material, being rigidly secured to opposite edges of said platform, by screws 7 or other suitable means. Upon said platform is vertically mounted an electro-magnet comprising a core 8 and its winding 9. The magnet seats upon a block of insulation 10 which rests freely on the platform 6 and is rigidly secured to the core 8 by a tap-screw 11. The ends 9 of the winding 9 are electrically connected to a pair of terminals 12 which embrace opposite end portions of said insulat- G0 ing block. As is best seen in Figure 3, these electrical connections may be established by the same screws 13 which secure said terminals to said block. Spaced from the terminals 12 is a pair of metal terminal blocks 14 G5 and 14 rigidly secured to the platform 6 by screws15 or the like. A pair of screws 16 engage said blocks with the terminals 12., establishing an electrical connection between these parts and holding the magnet in proper place upon the platform. It is to be noted that these screws permit the magnet to be ad justed to or from either of the blocks 14 and 14.

At its upper end, the magnet carries a polepiece 17 suitably secured to the magnet core, as for example by a screw 18. To increase the magnetic field it is preferred to elongate said pole-piece transversely to the core 8, so that its end portions project oppositely beyond the core. With said pole-piece there coacts an armature 19, secured by screws 20 or the like to the under face of an insulating plate 21, said armature being elongated corre' spondingly to said pole-piece. The plate 21 is carried by a pair of metal supports 22 secured by screws 23 to opposite edges of said plate. The plate 21 and its supports 22 form a bridge which extends over the magnet 8, 9, and is mounted to oscillate upon a pair of normally vertical leaf springs 24, extending at opposite sides of said magnet. The upper ends of said springs engage the metal supports 22, and may be secured by solder or other means in slits 25 formed in said supports. The lower ends of said springs are soldered or otherwise suitably secured to metallic mountings 26 attached to the platform 6 by screws 27 or the like, one of said mountings being preferably integral with the block 14. Preferably, the vertical plane established by the leaf springs 24 in their normal positions, lies to one side of the axis of the electro-magnet, and in the position occupied by the bridge 21, 22 when said sprin s are normal, the armature 19 is adjacent to but at one side of the pole-piece 17, so that magnetization of said pole-piece may attract the armature to the position above the pole-piece shown in dash lines in Figure 2. The position then assumed by the bridge 21, 22 and the resulting deflection of the springs 24 is also illustrated in dash lines in Figure 2. The top'face of the pole-piece 17 is rounded downwardly as it extends from the plane normally established by the springs 24 to provide the necessary clearance for swinging travel of the armature 19. Obviously the same result might be obtained by rounding the under face of the armature.

The insulating plate 21 carries a mercury switch comprised of 'a glass tube 28 having its ends closed by metallic caps 29 and 30. The tube 28 is closed at one end within the cap 29 and from said cap an insulated conductor 31 extends through the sealed end of the tube substantially axially of the latter and terminates adjacent to the cap 30 in a contact 32. The mercury level indicated at 33 is such as to slightly engage the contact 32 when the tube is in its normal horizontal position thus electrically connecting the contact 32 and its supporting cap 29 with the cap 30. When, however, the tube is tilted as shown in dash lines in Figure 2 the mercury no longer engages the contact 32 and the electrical connection between the caps is consequently broken. Said mercury switch is mounted preferably in two pairs of spring clamps 34 which are mounted upon the insulating plate 21, one at each side of the plane established by the springs 24. Said clamps are respectively connected to the supports 22 preferably through two of the screws 23.

It is desirable to mount upon the bridge 21, 22 one or more weights for regulating the oscillatory period of said bridge and the amount of its swing. Thus in the disclosed embodiment of the invention, a pair of weights 35 are 'adjustably surmounted on screws 36 which are respectively rigidly attached to the. supports 22 at opposite sides thereof and which preferably are oppositely inclined in the direction of oscillation, as is clearly seen in Figure 2. By thus'mounting said weights they maybe ad usted to vary both their distance above the bridge 21, 22 and to regulate their laterally spaced relation to the plane established by the springs 24. Increasing or decreasing the distance of the Weights above the bridge acts to increase or decrease the oscillatory, period and consequently regulates the number of oscillations per unit of time. The ratio between the periods of enorgization and deenergization of the circuit 37 is controlled by adjusting the weights with respect to the extended vertical plane of the leaf springs. That is to say if the weights are adjusted to act preponderantly upon the side of the bridge normally remote from the pole-piece 17, this will tend to prolong the closed circuit periods, and a reverse adjustment of the weights will tend to prolong the open circuit periods.

The lower ends of the standards 2 and 2 from terminals 36 and 36 for a circuit 37 which may be energized from any suitable source (not shown) which will contain the light or lights 38 (or other devices) which it is desired to periodically energize, from either of said terminals. In flowing from the terminal 36 to the terminal 36 the current passes up through the standard 2, through the pivot member 4 to the hanger 3, down through the latter and through the bent foot 39 thereof to the mounting 26 of the adjacent spring 24; up through said spring to the corresponding metal support 22, thence to the mercury switch through one of the screws 23, through the other screw 23 to the other metal support 22, down through the other leaf spring 24 to its mounting 26 and the terminal block 14 integral with said mounting, through the screw 16 engaging said mounting to one of the terminals 12, through the winding 9 of the magnet to the other terminal 12, through the other screw 16 to the block 14, from the latter to the hanger 3 through its bent lower end 40, and down through the standard 2 to the terminal 36. From the foregoing description it will be evident that the lights 38, the magnet winding 9, and the mercury switch 28, 29, 30 are I connected in series and that upon initial energization of the circuit 37 the armature 19 will be attracted to the pole-piece 17 deflecting the springs 24 and so tilting the mercury switch as to break said circuit. The rebound of the springs 24 will now carry the bridge 21, 22 to the other side of its normal position oppositely tilting the mercury switch and fully closing said circuit. This will again cause attraction of the armature by the magnet, the described cycle thus being repeated indefinitely.

The described suspended mounting of the platform 6 tends to automatically level said platform and to consequently maintain the proper normal vertical position of the springs 24 even though the base 1 may not be level. It is, of course, to 'be understood that the platform might be variously mounted to secure the desired automatic leveling thereof.

The described oscillating bridge, electromagnetically actuable, may be employed as a motor to energize any device requiring only slight power periodically applied.

If it is desired to control a plurality of circuits by the described mechanism, this may be readily done by using several pairs of leaf spring: to mount the bridge 21, 22, and by provi 'ng a corresponding number of mercury switches upon said bridge respectively included in the separate circuits established through said pairs of springs.

It is a highly desirable feature of the described device that there are no parts requiring lubrication or other attention and that there is no appreciable wear upon the parts resulting from'operation of the device.

If desired, the electro-magnet may be mounted for oscillation upon springs similar to those indicated at 24 and the upper end of said magnet may co-act with a stationary armature While the lower end of the magnet may periodically actuate any desired part;

' It is to be noted that the movement of the bridge21, 22 and mercury switch toward the pole-piece 17, responsive to initial energization of the magnet tends to first wash the mercury to the left (see Figure 2) and into more complete engagement With the contact 32 and the adjacent cap 30. The mercury then shifting to the lowered right hand end oi the tube and opening the switch. Conversely the retractive movement of the bridge first causes a surge of the mercury to the right (Figure 2) and away from its circuit closing position, completion of said movement effectin an accumulation of the mere in the to e so as to again close the circt c. The described action makes the device more positive in its action, 7

V/ l claim is:

l. The combination with an eiectr --magnet and its armature, oil a spring eldably mounting one of said parts for oscihation to from the other, and a mercury switch movable with the oscillatory part closed in the normal position of said art, and opened when said parts are attracte one toward the other, said spring establishing an el ctrical connection between said switch and magnet.

2. The combination with an electromagnet and an, armature, oscillatory to and from said magnet, of means normally holding the armature yieldably retracted from the magnet, a mercury switchanovable with said armature closed in its retracted position, and open in its attracted position, means for moving the magnet relative to the armature com prising an adjusting screw, and means electrically connecting said switch and magnet established through said screw.

8. The combination with an electromagnet comprising a core and its winding, of a pole piece mounted upon one end of said core,an oscillatory armature coacting with said pole-piece, a pair of terminals carried by the other end of said core, means for adjusting said magnet with respect to said an mature comprising a pair of screws, one engaging each of said terminals, and means for energizing said winding through said screws.

4. The combination with a platform and an electro-magnet vertically carried by said platform, and com rising a core and its Winding, of a pole-piece upon the upper end of said core, an oscillatory armature coacting with said pole-piece, an insulating member secured to the lower end of said' core, freely resting upon said platform, a pair of terminals for said winding secured to said insulating member and means engaging one of said terminals for adjusting said magnet upon the platform with respect to said armature.

5. The combination with an electro-magnet comprising a core and its winding, of a bridge extending across one end of said core, an armature upon said bridge coacting with said core, a pair of spring supports for said bridge extending at opposite sides of said magnet, and adapting the bridge and armature TOE oscillation responsive to said magnet, a normally closed switch controlling said magnet, opened by said bridge when the armature is attracted to the core.

6. The combination with an electro-inagnet comprising a core and its winding, of a platform engaged by one end of said magnet, a bridge extending across the other end of said magnet, an armature on said bridge coacting with said core, a pair of swinging support for said bridge extending at opposite sides oi said magnet and mounted upon said platform, and normally retracting said armature irom said core, a normally closed switch controlling said magnet windin opened by said bridge through attraction or en; armat by s id col 2.

l. The combination "h an electro-magnet com ising a core its winding, of a bridge ex nding across o e end of said core, armature upo oacting with said core a non ercury switch g said winding and adapted to be op rough attraction of the arm re to the core, pair of swinging supports for the bridge, extending at op posite sides of the magnet, normally retracting said armature from the core, and electrically connecting said switch and magnet winding. 2

8. The combination an electro-magnet and an armature oscillatory in a direction approximately transverse to the axis the magnet, of means for usting said mag in the direction of oscillation of the armature.

9. The combination with an electromagnet comprising a core, and its winding, and an oscillatory armature coacting with one end of said core, of a common means carried by the other end of said core for adjusting the magnet with respect to. said armature and for establishing electrical connections to said winding.

10. The combination with an electro-magnet comprising a core and its winding, of an armature coactin with said core, a swinging support for sai armature, normally retracting the armature from said core, means for periodically energizing and de-energizing 5 said magnet through swinging of said sup port, a pair of weights mounted upon said support, and means for independently adjusting said weights, one in each direction of osclllation of the support.

11. The combination with a platform, of a relatively oscillatory electro-magnet and armature, a normally vertical swinging support mounting one of said relatively oscillatory members upon said platform, means relatively fixing the other of said members upon said platform, establishing a normal retracted relation between said members, means swingingly supporting said platform, tending to automatically level the platform,

and means for making and breaking the circuit of said magnet through relativeosciL lation of said magnet and armature.

12. The combination with an electro-mag net comprising a core and its winding, of a bridge extending across one end of said core,.

an armature upon said bridge coacting with said core, means engaging the ends of said bridge adapting it for oscillation transversely to its length, responsive to said mag net, and a normally closed switch opened by said bridge when the armature is attracted to said core, and controlling said magnet.

13. The combination with an electro-magnet comprising a core and its winding, of a bridge extending across one end of said core, an armature upon said bridge coacting with said core, a normally closed switch on said bridge, controlling said winding and adapted to be opened through attraction of the armature to the core, and a pair of swinging supports for the bridge, extending at opposite sides of the magnet, and normally retracting said armature from the core.

14. The combination with an electro-magnet comprising a core and its winding, of an armature coacting with one end of said core, a support for said armature, an arm extend ing in approximate parallelism with said core,- providing at one of its endsa support for said armature and oscillatory about its other end to provide for attraction of the armature by the core, and a switch adapted to be opened and closed through oscillation of said armature, and controlling said magnet.

In testimony whereof I sign this specification.

EDWIN M. CLARK.

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