US2397219A - Timing device - Google Patents

Description

March 26, 1946. w. R. 'TALIAFERRO TIMING DEVICE Filed March 18, 1944 INVENTOR William R 7E1I iaferro.

ATTORNEY WITNESSES:

. magnetic flux decay.

PatentedMar. 2c, 1946 TIMING DEVICE William B. Taliaferro, Edgewood, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application March 18, 1944, Serial No. 527,116

8 Claims.

My invention relates to timing devices and par ticularly to timing relays to be used in electric circuits.

The known and customary timing devices contain as a'rule a timing mechanism such as a clockwork, escapement or flywheel device, or the delay between the actuation of the device and the desired function performed thereby is obtained by electromagnetic means such as a short circuited winding on a magnet core. Devices equipped with an escapement or the like mechanism are rather intricate and space consuming, while short-circuited windings; as a rule, require alternating current excitation and permit obtaining only limited timing periods. In cases when direct-current excitation is to be employed, only very short timing periods are obtainable with the known devices of simple design, and the timing is as a. rule effective only when the excitation is switched on or oil but not under both conditions of operation.

It is an object of my invention to provide a timing device which permits obtaining a period of delay within wider limits than those possible by direct current relays with short circuited windings and other means of producing a delayed More particularly, my invention aims at obtaining devices of long timing periods which do not require the use of an escapement or the like mechanism.

Another object of the invention is to devise a timing relay which is applicable for both alternating current and direct current excitation.

Still another object is to provide an electromagnetic timing device or relay which operates upon energization as well as on deenergization of its control magnet, or which secures a desired timing period under both control conditions.

In order to achieve these objects my invention takes advantage of the so-called cold-flow properties of plastic materials, in particular compositions of resinous nature. It is well known that when such a material is subjected to steady deterials can also be used, provided the material is in a relatively low' state of polymerization or contains plasticizers or modifiers in a suflicient amount to secure the necessary cold-flow deformation.

The stress produced by the actuating or control means of a relay or timing device according to the invention may act in compression or expansion or produce torsional or bending stress on the coldflowing plastic material, and the shape and dimensions of this material are chosen with respect to the stress so that the resulting deformation assumes a given magnitude within the desired timing period. The configuration ofthe body of cold-flowing material may be chosen according to the needs of each intended application, for instance, it may form a spiral, helix, diaphragm, rod or bar.

The invention will be more fully understood from the following description of the embodiment illustrated in the drawing in which Figure 1 shows a partly sectional view of an electromagnetic timingrelay, while Figs. 2 and 3 represent a top view and a lateral sectional view of the coldflowing body and some elements of the appertaining assembly.

According to the drawing, a substantially U- shaped support I of rigid material, for instance iron or brass, carries a movable arm structure 2 which forms two parallel legs 3 and 4 each providedwith outwardly extending studs 5 and 6, respectively. These studs are pivoted in angular journals 1 and l which are rigidly secured to thesupport I.

A transversely extending brazing section 9 of r the arm structure 2 forms an eye at HI, and a similar section H is Provided with an eye l2. A third transverse section l3 serves to render the arm structure sufllciently ri d.

An insulating pin ll is firmly mounted on the peripheral end of the arm structure 2 and serves to actuate the contact means mentioned hereinafter.

An extension spring Ii of helical shape is attached to support I and engages eye M. A second helical extension spring i5 connects eye l2 with the armature l? of an electromagn'et whose magnet frame i8 is firmly secured to the supp rt 6. The magnet coil is denoted by ES.

An insulating member 20 is firmly secured between the legs of the support i so as to form a rigid supporting structure for two pairs of contacts denoted by 2|, 21 and 23, 2|, respectively.

The above-mentioned body 0! coldefiowlng plastic material consists of a bar 25 of rectangular cross section. Tins bar is clamped to the support l by means of a sleeve 28. The other end of bar engages a similar sleeve 2?. Sleeve 2? is pro vided with studs 28 and 29 which engage elongated holes of the legs 3 and it such as the hole denoted by in Fig. 1. Due to this design, the bar 25 is subjected essentially only to bending stress during the operation of the relay.

When the coil it! is deen'ergizeol the spring 05, acting as a return or biasing device, holds the arm structure 2 in the position shown in. Fig. l. in this position the insulating pin it rests against contact 22 and thereby closes the circuit between contacts 20 and 22.. When cell it is energized it attracts the armature it immediately and thus puts the spring it under tension. .The force of spring it is so chosen that it exceeds the biasing force of spring in and hence tends to move the.

arm structure 2 downwardly, However, the coldfiowing body 25 prevents an immediate motion of the arm structure, but, under the continuous force produced by the electromagnet, yields grad ually so that at first the engagement between contacts 2i and i2 is opened. Upon elapse-of a timing period, the engagement between contacts upon elapse of a timingperiocl, contacts 2i and 22 are closed.

It will be apparent from the above described on ample of my invention that the timing period provided by the cold-donning body can be varied within wide limits by selecting the distance between the contacts or stops and thereby the degree of deformation necessary for obtaining the intended control operation. recognized from the example that the timing period is also dependent on the force of the biasing means and the force produced by the electromagnetic actuating device. Consequently the timing period can also be varied by a proper selection or adjustment of the actuating and biasing means. In order to permit such an adjustment two adjust= ing screws ti and 32 are provided. The screw 8i permits varying the travel of the armature ill and hence the force exerted by spring it on arm structure 2 when the coil ill is energized. The screw 32 permits varying the biasingiorce ex erted on the arm structure by the spring 05.

A third way of varying or adjusting the time period consists in selecting the dimensions of the body 25. For instance, a smaller cross section and a greater length of the bar result in a reduced timing period while an increase in cross section or reduction in length has the opposite efiect.

As mentioned previously, thetiming period is also determined by the selected composition of the cold-flowing material. A large number of such substances are known and available. Appllcable for the purpose oi-my invention are. for instance, vinyl chloride resins, polystyrene resins, copoiymers of vinyl acetate and vinyl chloride, methyl methacrylate, cellulose acetate.- nylon resins, copolymers of styrene and modified "glycolmaleatc esters.

Timing devices according to my inventionhave also the advantage that they are. inherently shockproor". For instance, when c. relay as illus-= trated in the drawing is subjected to impact shock,

Slit

It will further be assume for instance, on board oi ship or on vehicles, the shock forces and vibrations caused by the impact are either of short duration or of high frequency as compared with the normal operation of the relay by the continuous force produced by the electromagnetic or other actuating device, or by the biasing effect of the return spring, The cold flowing body oiiers an extremely high resistance to short-lasting or high-frequency stresses. Consequently, the movable assembly of the device, even if not dynamically balanced, tends to retain itspreshock position but permits the actuating magnet to perform its normal function even during the persistence of shock iorcesor vibrations. In this respect, devices according to my invention are simpler and more eflectiv'e than many of those heretofore proposed for use under conditions where impact shocks are to be expected.

in view of the fact that timing devices ac cording to my invention canlce modified in various respects by those skilled in the without departing from the objects, advantages and nrin= ciples of my inventioml wish this specification to be understood as illustrative rather than in a limiting sense.

I claim as my invention: l. A timing relay comprising a body of resinous -cold=-iiowing thermoplastic material, an electro magnetic actuating device having a movable armature connected with said body ionsubjecting it to cold-flow deformation, and contact means disposed on said structure relative to said body so as to be controlled thereby upon occurrence of a given cold-flow deformation of said body.

2. A timing device comprising a stationary structure, a body of cold-flowing resinous plastic material having one end secured to said structure, an electric actuating device having a movable actuating member connected with the other end of said body for subjecting it to cold-flow defor mation when operative, and contact means controlled by said body in dependence upon its deformation for controlling a circuit upon elapse of a'period of given cold flow deformation.

3. A timing relay comprising a stationary structure, a body of cold-flowing resinous plastic material having one end secured to said strum ture, an electromagnetic actuating device having an armature connected to the other end of said body for subjecting it to bending deformation when operative, and contact means disposed on said'structure in the path oi the deforming mo tion of said bodysc as to be actuated thereby upon a given deformation thereof.

4. A timing relay comprising a stationary structure, an elongated body of cold-flowing thermoplastic material having one end secured to said structure, a controllable source of mechanical power connected to the other end of said body for subjecting it to cold-flow deformation in a given direction, biasing means connected with said body for subjecting it to cold-flow deformation in the opposite direction, and contact means time-controlled by said body so as to be actuated in dependence upon a given deformation thereof.

5. A timing relay comprising a stationary structure, a body of cold-flowing resinous plastic material having one end secured to said structure,

an electromagnetic actuating device having an armature connected to the other end of said body said body for subjecting it to cold-flow deformation in the opposite direction, and contact means time-controlled by said body so as to be actuated in dependence upon a given deformation thereof.

6. A timing relay comprising a stationary str dcture, a body of cold-flowing resinous plastic material having one end secured to said structure, an electromagnetic actuating device having an armature and a spring connecting said armature with said body for subjecting it to cold-flow deformation in a given direction, a biasing spring connected with said body for subjecting it to coldflow deformation in the opposite direction, and contact means time-controlled by said body so as to be actuated in dependence upon a given: deformation thereof.

7. A timing relay comprising a stationary structure, a rigid member having one end pivoted to said structure, means for biasing said member towards a given pivotal position, a controllable source of mechanical power connected with said member for moving it in opposition to said biasing means, a body of cold flowing plastic material disposed between said structure and saidmem ber so as to retard the angular motion of said member produced by one of said biasing means and said source respectively, and contact means disposed relatively to said member so as to be actuated thereby upon occurrence of a given pivotal travel thereof.

8. A timing relay comprising a stationary structure, a rigid member having one end pivoted to said structure, means for biasing said member towards a given pivotal position, an electromagnetic actuating device having an armature and a spring connecting said armature with said memher for moving it in opposition to said biasing means, a body of resinous thermoplastic material disposed between said structure and said member so as to retard the angular motion of said member produced by one of said biasing means and said source respectively, and contact means disposed relatively to said member so as to be actuated thereby upon occurrence of a given pivotal travel thereof.

WILLIAM R. TALIAFERRO.

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