US2226070A - Time delay relay - Google Patents

Description

Dec. 24, 1940. M NELSEN 2,226,070

TIME DELAY RELAY i Filed Nov. 22, 1939 lNsULATloN 23M v 23 2%* 0/ 1G63 Q I Patented Dec. 24, 1940 UNITED STATES PATENT' OFFICE I TME DELAY RELAY Application November z2, 1939, serial No. 305,607

Claims.

The present invention relates to electrical current responsive devices, and more particularly to relays of the time-delay type adapted for making or breaking an electrical circuit after the lapse of 'a predetermined interval of time subsequent to the initiation of the operation of the relay device. Devices of this general class are utilized primarily as timing devices for controlling the operation of various types of electrical circuits and apparatus. Such devices may also be employed for producing a pulsating or periodic ow of' current at predetermined timed intervals, such as in flasher or signaling circuits, electric fence systems, etc. l

One of the objects of this invention is to provide an improved device of the character indicated which is capable of operation by a relatively small amount oi.' current, so as to render the device extremely sensitive in operation and capable of -0 adaptation to a relatively wide field oi use.

Another object is to provide an improved device of the type indicated, which is characterized by the provision. of aswitch arranged to be controlled by a single strand of ne resistance wire looped in a manner to provide two portions extending in the same direction for effecting relatively sensitive control of the operation of the switch. p

A further object is to provide an improved device lot the type indicated, characterized by the provision of a single strand of resistance wire looped in va manner to-provide two portions extending in the same direction and placed under tension, a'. switch connected in an electrical circuit to be controlled, the switch normally being biased to one position of adjustment, together with means interconnecting the looped end portion of the wire, constituting the connection between said two portions, and the switch to normally hold said switch against biasing movement luntil the tension of said wire is reduced by energization thereof.

Still another object of my invention is to pro- ,-vide an improved device oi.' the character indicated, which has relatively few moving parts, is simple in construction, and positive in operation, and which is capable of being economically manuiactured. t Other objects and advantages of this invention will be apparent from the following description taken in connection with the accompanying drawing, in which: Fig. 1 is a full size top plan view 'of the timedelay relay device embodying the present invention.

(Cl. 20G- 113) Fig. 2 is a side velevational view of the device.

Fig. 3 is a vertical, staggered section through the device taken substantially as indicated a line 3-3 on Fig. l.

Fig. 4 is a bottom plan view of the device. 5

Referring more particularly to the drawing, the relay device III embodying the present invention is constructed as a unitary assembly and includes a metallic mounting plate or base II in the form of a stamping. Said base is of generally 30 elongated, rectangular form having opposite sides provided with downturned flanges I2, and the ends thereof being provided with downturned leg portions I3, the lower ends of which are bent and extend outwardly at right angles thereto to form 15 feet I4, provided with suitable apertures I5 for convenience in securement to a mounting. One of the leg portions I3 is formed with an aperture in which is mounted a ferrule I6 through which o conductor wires, hereinafter described, extend. Secured to the underside of the mounting base II, by means of rivets I'I, is a rectangular panel of insulating material indicated at I8.

An upstanding lug 20 is struck out ofthe base plate I I and has rigidly attached thereto a switch 25 unit, designated at A, including a pair of cooperating, ilexible conductor fingers 2l and 22, formed of relatively dat stock and disposed in upright edge relation substantially perpendicularly, and in vspaced parallel relation to said 30 base II. Said fingers are rigidly secured between blocks 23 of insulating material, and the switch .assembly being firmly secured to the upstanding lug 20 by means of screws 24. Said switch fingers are provided with cooperating contact buttons 3 0 2|* and 22, respectively, which, as shown in Fig. '1 ofthe drawing, are positioned normally in engagement with each other.` The switch ringer 2| is of slightly greater 'length than switch ringer 22, and secured .to the extreme end por- 40 tion or said iinger 2| is a button 26 of insulating material. While said lingers are' of a flexible character, it is to be understoodl that nger 2l is formed to normally assume a position indicated by dotted lines in Fig. 1, with contact buttons 2 I 45 -and 22* in separated relation.

. a sleeve or bushing 3L the upper end of which is shouldered to provide a seat for a bell crank lever 32, which is disposed in a plane substantially 55 parallel to the base and in alignment with the switch fingers. The upper end of the stud 30 is riveted over to confine said lever and sleeve in position, but permitting unrestricted rotary movement thereof. Said lever includes a relatively long arm 33,the outer end of which is formed with a nubbin for sliding engagement against the button 26 of insulating material on the outer end of switch finger 2|. The other arm of the lever, as indicated at 34, is relatively short as compared to arm 33 and extends substantially at right angles to said arm 33.

The bell crank lever 32 is normally held in the position seen in full lines in Fig. 1 of the drawing, with the nubbin engaging the insulating button 26 for maintaining the switch fingers 2| and 22 with their contact buttons 2 |a and 22e in engagement with each other. The means for accomplishing this consists of a strand of fine resistance Wire, such as Nichrome wire, normally under tension, indicated at 31, which is firmly anchored at opposite ends and looped around the short lever arm 34 in a manner to provide two portions of wire extending in the same Ydirection and preferably, though not necessarily, in substantial alignment. yOne end of said wire is extended through an aperture in and then wrapped around a stud 38 rigidly secured in the exposed portion of the panel |8 of insulating material in regis-.

tration with opening 28 of the base The other end of the wire is extended through an aperture in and wrapped around a stud 39 rotatably mounted on the panel of insulating material in the area in registration with the opening 28 of said base |I. The upper end of said stud 39 is formed with a slot 40 for convenience in engagement by a suitable tool for rotating same and thereby adjusting or varying the tension on the strand of resistance wire 31. Said stud 39 is frictionally held in a desired position of adjustment by means of a spring member 4|, seated against a shoulder base of the stud, and is formed with a downturned leg 42 extending through an aperture 43 formed in said panel of insulating material. As seen in the drawing, the fixed stud 38 is shorter than the rotatable stud 38, and said studs are disposed substantially in alignment with respect to the short lever arm 34 so that the two portions of the resistance wire are substantially alignedin the same vertical plane. It is to be understoodA that the tension on wire 31 is normally suiiicient to maintain the lever 32 in position to hold finger 2| in position seen in full lines in Fig. 1, in opposition to the biasing force of said finger.

In the construction illustrated, the resistance wire 31 is connected in an electrical circuit independently of the circuit to be controlled by the switch A. A conductor wire 45 is connected to the downturned leg 42 of the spring member 4|, and a conductor wire 46 is connected to a terminal on the fixed stud 38, and the opposite end of said Wire is connected to the terminal end of conductor finger 2|, from which terminal anotherconductor Wire 41 extends for connection in the electrical circuit. Another conductor wire 48 is connected at one end to the terminal of the switch finger 22.

In the operation of the device of the type shown in the drawing, the switch A is normally closed and as the resistance wire 31 is energized, it iscaused to elongate, thereby reducing its tension and permitting the bell crank lever 32 to be swung in counter-clockwise direction by the yielding biasing force of the spring finger 2|, which,

as above mentioned, is normally biased in af direction for separating its contact button 2| from cooperating contact button 22, and breaking the circuit controlled by said switch. Under such conditions, the tension of the wire does not exert a force on the lever 32 to oppose the biasing movement of the contact nger 2 and said finger thereby moves to the dotted position indicated in Fig. 1 and moves said lever to the dotted position indicated, under control of the reduction of tension in the wire 31. When the switch circuit is thus opened, it remains in such condition until the circuit including the resistance wire is opened, permitting said wire to cool and contract, thereby increasing/its tension to its normal value and exerting a pull on the short lever arm -34 for again causing said long lever Aarm 33 to act on the insulating button 26 and move the switch finger 2|, in opposition to its biasing force, so as to dispose its contact button 21|a in engagement with contact button 22a to close the switch. It is preferable that in the clorjed position of the switch and in the iinal position of adjustment of the lever, the force imparted through the nger 2| results in slightly ilexing said finger 22 outwardly so that the contact buttons, in their engagement and disengagement, are subjected to a slight wiping action, thereby cleansing the surfaces thereof and prolonging' their life.

Although I have shown and described a construction wherein the switch is connected in a circuit independently of the circuit including the resistance wire 31, manifestly, if desired, said wire and switch (when said switch is of the snap or toggle action type) may be connected in series in the same circuit so as to effect intermittent opening and closing of the circuit controlled by said switch for producing an intermittent or pulsating or periodic flow of current. The device, when so constructed, lends itself to wide fields of utility which require pulsating or periodic current, such as in flasher or signaling systems, electric fence systems, etc.

The relation and arrangement of the resistance Wire 31 so as to provide two portions` of substantial length permits using extremely fine wire which lmay be properly energized by use of a relatively small current, which in addition to lending itself to use in operating apparatus of the type which likewise require a small amount of current, also provides a device of relatively great sensitivity. It will, therefore, be apparent that by using two portions of fine resistance wire, in the manner indicated, in addition to the foregoing advantages, rerults in producing adequate power, `'when the wire is tensioned, for properly controlling the operation of the switch.

It will be apparent that, if desired, the switch may be of reversed relation; in other words, it may be normally opened with one of the finger members biased to closing position, with the lever member positioned for normally holding the biasing switch member at its open position in opposition to the biasing force of said finger.

The tension in the resistance wire, as above mentioned, may be varied by merely rotating the adjustable screw 39 so as to vary the period or time interval for effecting opening or closing of the switch. This periodic timing, however, may

also be varied by employing different size wire or a different length of wire or by varying the amount of current passed through said wire.

Although I have herein shown and described a preferred embodiment of my invention, manifestly it is capable of modification and rearrangement of 75 parts without departing from the spirit and scope thereof. I do not, therefore, wish to be understood as limiting this' invention to the precise form herein illustrated and described, except as it may be so limited in the appended claims.

I claim:

l. A device of the character described, compris-v ing a base, a switch mounted on said base, and including two cooperating conductor members, one of said conductor members being movable and normally yieldingly biased in one direction with respect to the other member, a bell crank lever pivotally mounted on said base and having a short arm and a. relatively long arm, the latter arm being positioned in engagement with said movable switch member, a pair of spaced-apart terminals on said base, and a strand of resistance wire, connected in an electrical circuit, said wire being connected at its ends to said terminals and having av Jportion intermediate its length looped around the short-arm of said lever for normally maintaining the long arm of said lever in engagement with the movable switch member, said wire, when de-energized, serving to position said long arm of the lever for opposing biasing movement of said movable switch member. I

2.- A device of the character described, comprising a base, a switch mounted on said base, and in- Y cluding two cooperating conductor members, one

of said conductor members being movable into and out of cooperative engagement with the other member, a bell crank lever pivotally mounted on A said base and havingl a short arm and a relatively long arm, the latter arm being positioned in operaltve engagement with said movable switch member, a pair of spaced-apart terminals on said base, and a strand of resistance wire, connected in an electrical circuit, said wire being connected at its ends to said terminals and having a portion int-ermediate its length looped around the short arm of said lever for normally maintaining the long arm of said lever in operative engagement with the movable switch member, said terminals being spaced-apart in close proximity to each other and aligned relatively to the short arm of the lever so that both portions of said wire extend in the same direction.

3. A device of the .character described, compris- 4ing a base, a switch'mounted on said base, and

said base and having a short arm and a relatively long arm, the latter arm being positioned in operative engagement with said movable switch member, a pair of spaced-apart terminals on said base, and a strand of resistance wire, connected in an electrical circuit, said wire being connected at its ends to said terminals and having a portion intermediate its length looped around the short arm` of said lever fornormally maintaining the long arm of said lever in operative engagement with the movable switch member, said terminals being spaced-apart .in close proximity to each other and aligned relatively to the short arm of the lever so that both portions of said wire extend ,one above the other in substantially the same plane.

4. A device of the characterdescribed, comprising a base, a switch mounted on said base, and including two cooperating conductorl members, one of said conductor members being movable and normally yieldingly biased in one direction with respect to the other member, a bell crank lever pivotally mounted on said base and having a short arm and a relatively long arm, the latter arm being positioned in engagement with said movable switch member, a piece of insulating material interposed between said long arm of the lever and said movable switch member, a pair of spaced-apart terminals mounted on and insulated from said base, a strand of resistance wire connected in an electrical circuit, said wire being connected at its ends to said terminals and having a portion intermediate its length looped around the short arm of said lever for normally maintaining the long arm of said lever in engagement with the -out of cooperative engagement with the other member, a bell crank lever pivotally mounted on said base and'having' a shortl arm and a relatively long arm, the latter arm being positioned in operative engagement with said movable switch member, a pair of spaced apart terminals on said base and a strand of resistance wire connected in an electrical circuit, said wire being connected at its ends to said terminals and having a portion intermediate its length looped'around the short arm of said lever for normally maintaining the long arm of said lever in operative engagement with the movable switch member.

MARVIN G. NISEN.

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