US2354635A - Flasher switch - Google Patents

Description

July 25, 1944. L` R, mm/[QNy 2,354,635

FLASHER SWITCH Filed Nov. 19, 1942 IIA M n. WM

Patented July 25, 1944 i z,ss4,sss

FLASHEB SWITCH Luther E. Harmon, Chicago, Ill., assigner oi'` thirty-seven and one-half per cent to Fred Burt, thirty-seven and one-half per cent to William D. Lloyd, and twenty-live per cent to Patterson Manufacturing Company, a corporation of Illinois Application November 10, 1942, Serial No. 466,218

6 Claims. (Cl. 200-113) ing or injurious sparking.

In flashing systems, it is necessary to use an intermittently operated switch for making and breaking the circuit. It the switch contacts do not separate quickly and clearly, there is apt to be much sparking that soon burns the contacts.

To prevent burning oi' the contacts. it has heretofore been more or less the practice to use platinum in the construction of the contacts. Platinum however is very costly and greatly increases the cost of such switches.

'I'his invention is designed to overcome the above noted objections in the construction of a snap switch in which the contracts make a quick and clear separation without any objectionable sparking and burning whereby the use of costly materials such as platinum may be avoided.

The invention comprises the novel structure and combinations hereinafter described and more particularly pointed out and deilned in the appended claims.

In the accompanying drawing which illustrates a preferred form of this invention and in which similar reference numerals refer to similar features in the different views:

Fia. l is an elevational view oi' a nasher switch involving this invention.

Fig. 2 is an enlarged top plan view of the same.

Pig. 3 is an enlarged sectional view taken upon the line 3 3 of Fig. 2 looking in the direction of the arrows.

ng. 4 is an enlarged sectional view taken uponv the line t-I of Fig. 2 looking in the direction of the arrows.

Fig. 5 is a diagrainmatic view illustrating the wiring diagram.

In referring now to the drawing. it will be observed that the switch'mechanism is mounted upon an insulated base I from which extend a pair oi' substantially parallel metal frame members 2 and t which are inwardly offset at their upper portions as indicated at 2a and la to provide a somewhat restricted space therebetween. These frame members are shown as extending in vertical planes though they may be made to extend in other suitable planes and they are preferably integral with a base portion I secured to the base I by a conducting rivet 5 which also secures a terminal post 6 for the flashing lights to which reference will later be made.

Between the restricted portions of the frame. there is pivoted a metal lever 1 ci conductive material. y'l'his lever 'I is oi the bell crank variety having one arm 'la extending at substantially a right angle to the other arm 1b with the pivot l of the lever extending thruthe elbow of the lever and into the frame members. A resistance wire 0 is attached at oneend to the outer end of arm la; the other end of the wire is attached to a spring bracket I0 iastened to the base I. It will be noted that the bracket I 0 has a foot Ila secured to the base I by an electrical conducting rivet II which extends thru the base and secures a terminal post I2 upon the bottom of the base. The bracket Il also has an upstanding portion Ilb thru which a screw Il extends that is threaded in the base I and is adiustable for varying the elevation of the upstanding portion IIb of the bracket I0 for loosening or tightening the resistance wire l.

The arm 'Ib oi the lever 1 terminates in a bifurcation Il. One side or wall of this bifurcation has a contact point Il while the opposite side or wall is insulated as indicated at It.

A spring-like or yieldable snap-switch member il preferably made of beryllium copper has a free end or tail I'la extending into the bifurcation Il between the contact Il and the insulation I..

This snap switch member which is a good elec-` trical conductor has an attaching portion IIb secured to the basel by the rivet l so as to conduct the current to the post l. spaced inwardly or downwardly from the free end Ila of the switch member. there is a second securing means which consists of a pin or rod Il attached to said switch member and extending thru the frame members 2 and I and projecting slightly therebeyond for a purposethat will later appear. This spring-like switch member I1 is adapted to be bowed in two directions between its attached points Ilb and Il for engaging and disengaging an adjustable contact in the form of a screw Il.

'I'he screw Il is mounted in the upper end portion of an electrical conducting bracket 2l (Fig. 3) which may beintegral with the base 2l oi an upstanding bracket 22 having a curved terminal.

2l. The base oi said bracket 22 is secured tothe base I by a rivet 24.

Spaced from the bracketv 22, there is shown a solenoid or coil 25 supported upon the base I for controlling a pilot light. An electrical conductor in the form of a rod 26 extends thru the coil Il and thru the base I. A pilot light terminal 21 isl attached to the lower end of said rod 26 and rests against the base I.

Current is idapted to be conducted to the rod 2l from a switch plate Il which is slotted and mounted over the curved portion 2l o! the bracket I2 which has arresting shoulders 2l for supporting said plate. A coll spring III secured at one end to the bracket 22 and at its other end to the tail of plate 2B, which it will be noted extends beyond the bracket, serves to normally hold the plate 28 against the end of the curved portion 2l of the bracket as shown in Fig. 4 in switch open position.

When the resistance wire 9 elongates thru the heating effect of the current passing therethrough, it will slacken its pull upon the lever 1 and allow spring 3i to move the lever arm 1b to the right as viewed in Fig. 3 and exert pressure against the tail I1a of the switch member I1 for a purpose that will later appear.

'The spring 3| consists of a pair of parallel arms ila anchored at their ends in the standards 2 and I as indicated at I2; the upper ends oi the arms being integrally connected by a cross piece or bridge 3 Ib which presses against the arm 1b of lever 1 as shown in Figs. l and 3. For this purpose, the standards are cut out as indicated at I3. To maintain the arms IIa under tension, they are positioned back of the projecting ends of the pin I8 as shown in Fig. 1.

An insulated wire 34 constitutes the coil 25; one end of the coil being in contact with the bracket III thru the rivet I I; the other end being connected to the base 2i of the bracket 22 as indicated at 35.

The current from any suitable source is led to the post I2 (Fig. l). From the post I2, the current may dow thru either of two paths depending upon the position oi' the switch member I1. If the switch member is out of contact with the screw I9 as shown in dotted lines in Fig. 3, the current will ilow thru bracket I0, resistance wire B, lever 1 and switch member II to post 8 which is connected to the flashing circuit which however will be ineffective due to the resistance; the current returning from the light to the source ot energy.

When the resistance wire 9 becomes heated thru the current passing therethrough, it will elongate as previously set forth and allow spring ll to exert pressure against the arm Ib of lever 1 and cause said arm to exert pressure against the tail I1a of the switch member I1 and cause said switch member I1 to bow and spring to full line position into contact with contact screw Il. When the switch member I1 is in full linel the current will flow from post I2 thru wire Il, to bracket 20, contact screw I9 and switch member I1. From switch member I1, the current will flow thru rivet to the dashing light circuit which will now be effective due to the stronger current. Part of the current from the wire 34 will pass thru the bracket 22 and switch plate 2l which will have been attracted against the rod 26 and thru said rod for illuminating a pilot light as will later more fully appear from the description of Fig. 5.

When the thermo-resistance wire 9 cools while no current is passing therethrough, it will contract and swing the insulated wall I5 of the bifurcation against the tail I1a of the switch member I'I and cause the same to bow toward the right as viewed in Fig. 3 and then snap away from Contact I9 very quickly and clearly without any injurious sparking or burning of the contacts and the lighting circuit will be broken and the resistance will again be established.

The operation can be more readily understood from a description of the wiring diagram shown in Fig. 5. In this Mure. it will be noted that the flashing light I1 is connected with the switch member I1 above the lower terminal for convenience and that the current from the battery I6 will now thru ground to point I2. Now il the switch I1 is open, the current from the battery Il will flow thru wire 4I, ground, and wire d! to point I2, resistance wire 9, lever 1, switch member I1 and wire Il to ilasher light I1 which however will be ineffective due to the resistance. When wire 8 cools, the switch member Il will be snapped to closed position as shown in full lines and the current from point I2 will now ow thru wire 34, solenoid 2l, wire I4 to post Il, switch member I1 and back to the battery. The flashing light 31 will now be illuminated and incidently, the solenoid 2l will complete the circuit to the pilot light 4l.

The reason for the quick and clear snap aetion of the switch member I1 away from eolitact Il arises primarily from the fact that the contact I8 is located some distance beyond the longitudinal center of the switch member I1 and beyond the part that bows. As a result, when pressure is applied to the tail I1a of the switch member I1 when it is in full line position, the switch member will be put under strain that will cause the bowed part to gradually move to the right (Fig. 3) in advance of any movement away from the contact I9. In other words, the action is such that the movement of the switch member I1 away from contact Il will be delayed until the bowed part has been brought substantially to the snapping over position. Thus when the snap action occurs, the switch member I1 will quickly and clearly snap away from contact Il and avoid injurious sparking and burning.

It will be appreciated that if the contact II were located at the bowed portion oi' the spring switch, there would be a gradual and hesitant movement oi such switch away from contact Il during the time that tension was being built up in such switch member with the result that sparking and burning occur.

From the foregoing, it will be evident that a novel switch admirably adapted for a asher has been invented that avoids injurious sparking and burning during the making and breaking oi circuits. It will be appreciated that overcoming the hesitant action of contacts in separating thru the building up of energy in the snap switch member so as to obtain a quick and clear break produces a highly desirable new result in such switches.

I am-aware that many changes may be made and various details of construction' modided without departing from the principles of this invention so I do not propose limiting the patent granted thereon otherwise than necessitated by the prior art and appended claims.

I claim as my invention:

l. In a switch of the class described, an insulated base, a frame extending from said base. a snap-action switch member secured at one end to said base, a pivot pin connecting said member with said frame at a point spaced from the other end of said member leaving a tall piece beyond said pivot point, an electrical conducting lever having a bifurcation receiving said tail piece. one wall of said bifurcation being insulated. thermoresponslve resistance means for moving said lever in one direction for exerting f pressure against said tail piece, yielding means for moving said lever inthe other direction for exerting pressure on said tail piece, said switch member being bowable between its supports and co-operating contacts, one located on said switch member beyond the greatest ilexlble portion of the bowable portion for the purpose set forth.

2. In a switch of the class described, a stationary contact, a yieldable snap-action switch member having a single bowable portion and a contact located beyond the greatest ilexibleportion of the bowable portion adapted for engaging said stationary contact, means for anchoring one and of said switch member, pivot means for supporting said switch member adjacent its other end. a conducting lever having a bifurcation engaging said switch member, said bifurcation having insulation upon one side and thermoresponsive means connected to said lever for controlling the movements thereof.

s. In s switch of me class described. an ml 4. In a flasher switch, a stationary contact, a

bowable snap action switch member having a contact adapted for engaging and disengaging said stationary contact. means for anchoring said switch member adjacent one end, pivot means for supporting said switch member adjaeent the other end, said switch member having a bowabie portion between said contact and other position.

pivot means and thermoresponsive means for initiating movement oi' said switch member for moving the same to substantially snap action position before causing separation of said contacts from engaged position, said initiating means including a member serving as an electrical conductor to said switch member in one position and being insulated from said switch member in another position.

5. In a flasher switch, a stationary contact, a snap actionswitch member having a contact for engaging said stationary contact. means for anchoring one end of said switch member. means for supporting said switch member adjacent the other end. said switch'member having a bowable portion spaced in a longitudinal direction from said contacts. a conducting lever having a bifurcation engaging said switch member and thermoresponsive means for initiating movement of said switch member to substantially snap action position before' causing separation of said contacts from engaged position, said lever serving-as a conductor to said switch member in one position and being insulated therefrom in an- 0. In a switch of the character described. a stationary contact, a snap action switch member having a contact adapted for engagement with and disengagement from said stationary contact, means for supporting said switch member at spaced points. said switch member having a single bowable portion sufllciently removed from said contacts in a longitudinal direction for movement to snap action position before separation of said contacts from an engaged position. and means including a thermoresponsive element for initiating movement of said switch member, said means also including a lever having a bifurcation for engaging said switch member and having one side wall of said bifurcation insulated.

LU'I'EER R. HABKON.

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