US2419232A - Time pulsing relay device - Google Patents

Description

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TIME PULSING RELAY DEVICE 5 AnnnnnAn/f INVENTOR.

Loa/s ,4. @cf/042 Patented Apr. 22, 1947 UNITED STATES PATENT OFFICE (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) 8 Claims.

The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to relays and more particularly to pulsing relays for closing or opening an associated circuit for a predetermined length of time.

Pulsing relays of the character described are useful in various applications in the photographic held for providing camera shutter and multicamera control and in various other fields where maintenance of an open or closed circuit for a preselected time interval is required. As is apparent from the foregoing, the terms pulse and pulsing will be understood to refer to maintenance of either an open or closed contact condition for any predeterminable time interval.

It is an object of the invention to provide a simple relay capable of closing or opening a contact and maintaining the closed or open condition for a predeterminable length of time, and having means whereby one of a variety of time intervals may be selected to suit given conditions.

It is a further object of the invention to provide a pulsing relay wherein the controlling components are not subject to material electrical change due to temperature variation, so that predetermined pulse intervals will remain substantially constant and unaifected by changes in temperature under normally met operating conditions.

It is a still further object oi the invention to construct the relay in such a manner that a portion thereof, which carries a continuous current, is wound at the outside of a layer type solenoid for purposes of expediting heat dissipation tending to maintain a uniform temperature of the solenoid.

In accordance with the objects, I provide a device comprising an inductance coil having various points provided for connection to a battery and a key, there being an armature associated with a ferrous core about which the coil is wound whereby under certain conditions of keying and unkeying the armature 'will be displaced for providing a pulse of predeterminable time in an associated circuit. The battery, key, and inductance coil arrangement is such that a portion of the coil is provided with a continuous current and acts as a holding coil for normally maintaining the armature in displaced, i. e., attracted position. Various sections of the remainder of the inductance coil may be selectively connected in such a manner that they oppose the iiux in the holding coil, such sections constituting a bucking coil for the purpose of overcoming the holding coil iiuX to release the armature, subsequently building up a resultant reverse flux strong enough to reattract the armature to its position of initial displacement. The bucking coil is energized by being manually keyed to a current source which may be the same current source energizing the holding coil. The connections to the coils are so arranged that the bucking coil iiux opposes the holding coil flux and produces a release and reattraction of the armature during the flux transient oi' the bucking coil; thereby pulsing the circuit associated with the armature. The time interval of pulse is determined by selective proportioning of the inductance of the bucking coil to the inductance of the holding coil. A second pulse is obtainable by unkeying or deenergizing the bucking coil, the time interval of pulse caused by deenergization of the bucking coil being substantially smaller for the same inductance ratio between the coils than the time interval during energization, as will be understood from the detailed disclosure which now follows, as will be other objects and features of the device taken in connection with the appended drawings, in which:

Fig. l shows a general schematic diagram of one form of the invention;

Fig. 2 illustrates a, iiux v. time graph of the operation of the invention;

Fig. 3 discloses a modification of the inductance proportioning arrangement; and

Fig. 4 shows a cross section of the electromagnet comprising the principal element of the invention.

With reference to Fig. 1, a ferrous core 2 is shown carrying a continuous winding 3 forming an electromagnet operative to attract an armature 5 against the pull of a spring 6 for contacting a member l to effect control of an associated circuit (not shown). Connections are made to the coil 3 at points designated A, B, C, D, E, and F. A switch or key I5 is provided for connection selectively to one of the points B-F as indicated by the solid and dashed arrows leading from the key, and a battery I6 is connected across armature is attracted towards core 2, depending on the use to which the relay is to be put. If now it be assumed that the coil connection D is connected to the key I5, as indicated by the solid arrow, and further assuming that the key I is closed by manual operation, or in any other manner depending on the nature of the installation, a current will begin to build up in the B-D section of the coil, which constitutes the bucking coil hereinabove mentioned and which has a greater inductance than the holding coil A-B. The north-south polarities of the coil sections are indicated on Fig. l. The following action then takes place, which will be described with reference to Y Fig. 1 and to the flux v. time relationship shown on Fig. 2 whereon the iull line 2-5 represents the steady state iluX of the continuously energized holding coil, armature 5 being in attracted position, i. e., displaced at this time. At the instant of keying key closed on the graph) a ux starts building up in the bucking coil, as indicated by the dot-dash line Due to an E. M. F. induced in the holding coil in the opposite direction to the E. M. impressed by battery IS a weakened resultant magnetic hun is produced during the initial energization of the bucking coil While the luX transient thereof is rising. The resultant flux is indicated by the dashed line 3o. When the resultant hun has decreased to the point where it can no longer hold the armature 5 against the pull o spring S, as designated by point 32 on the resultant linx line the armature is pulled back by the tension of spring 6, thereby breaking connection with Contact member l. The iiux in the bucking coil continues to build up until at a point on the resultant flux line 3U, armature 5 is again pulled in toward core E, the polarity of the resultant iiux being reversed as compared with the original flux in the holding coil section A-B. This restoration of the armature occ rs during the energization transient of the bucking coil which ultimately reaches a steady flux state of sufficient intensity to completely neutralize the holding coil While providing suiilcient flux to reattract the armature and also providing some surplus flux by way of a safety factor. The time interval measured on the abscissa of the graph between the points :i2 and 3 i represents a contact opening pulse, i. e., with the structure shown in Figure l, the time of open contact between the armature il and contact member '5. Obviously, where contact member l is so arranged relative to armature o that contact is made instead of broken at time of release of armature 5, then the time interval from to 33 would represent a contact closing pulse. lIhe time interval is predetermined by the inductance ratio between section A-B and section B-D It will be appreciated that were the point connected to the key I5, the flux transient of the bucking coil would have an increased time interval due to the added inductance oi section D- In this manner, by selectively connecting any or the points B-F to the key I5, it is possible to predetermine pulse intervals as desired in accordance with the inductance ratio of the holding and bucking coils.

Upon open ng the key i5 (key opened on the graph) dee el gization of the bucking coil induces an ivi. in the holding coil which is in the same direction as the E. Ii/i. F. impressed on the coil by the battery IS, and accordingly, the flux of the holding coil is transitorily increased, which flux being of opposite polarity to the bucking coil iux causes a rapid drop in the resultant iiux; permitting release of armature 5 at the point 38.

Following this transitory condition, flux in the holding coil drops to the steady state value until at the point 40 on the resultant curve the armature is reattracted and contact with member I is restored. The interval during which lghe armature 5 is released and reattracted is, of course, dependent on the inductance ratio between the holding coil and the particular section of the bucking coil in question, as well as on the strength of continuous current through t le holding coil due to the battery. It is apparent from Fig. 2 that for any given inductance ratio the time interval 38-49 for the unkeying operation is materially shorter than the time interval 32-34 provided by the keying operation, due to the transitory flux rise in the holding coil upon deenergization of the bucking coil. The versatility of the device to suit Widely varying pulsing needs is thus evident.

The principle of operation above disclosed is, of course, subject to considerable modification .spending on the intervals of pulsing desired for use in connection with any particular apparatus, it being necessary only to provide ratios of inductance bett een the holding coil and the various sections of the bucking coil to suit given conditions. In Fig. 3, e. g., is a modication of the inductance proportioning arrangement, the key being connected across the entire coil and the he invention, as shown in Figs. 1 and 3, the inluctance of the bucking coil always exceeds the '.-aductance ci the holding coil. This is true even hcugh on consideration of Fig. 3 a selected num- ;er of turns of the bucking coil may be less than the number oi turns of the holding coil; the explanation being that since inductance is a function or" ampere-turns, an arrangement is provided such that the ampere-turns of the bucking coil is at all times greater than that of the holding coil regardless or" the turns ratio, the coil section E-F being generally wound with a larger number of turns than the remaining coil sections in order to obtain the required effect.

The manner of winding the inductance of the coil is illustrated in Fig. 4 wherein it is Seen that the end ci the coil F begins the winding on the core '2 so that the holding coil A-B comprises the outer layers of coil 3. The advantage of winding in the described manner is that heat dissipation from the continuously energized holding coil A-B is expedited when it is at the outside of inductance coil f whereby access to the surrounding atmosphere is obtained.

The device described herein is operable on either alternating or direct current, as will be understood from consideration of Figs. 1 and 3, since the battery 5S may be connected with its terminals re ersed without alecting the ilux opposing function oi the holding and bucking coils.

I claim:

l. In a time pulsing relay, an electromagnet comprisng a holding coil and a bucking coil, an armature magnetically cooperative with said electro-magnet and biased away therefrom, means for impressing an ivi. en said holding coil for energization thereof to magnetically attract said toward said electromagnet, means for energizing said bucking coil whereby said holding coil has an opposing lvl. Fv transitorily induced therein operative to release said armature, energization of said bucking coil being operative to reattract said armature after a time interval from the instant of release, said time interval being predetermined by the inductance ratio between said holding coil and said bucking coil, and switch means operative by the release and return of said armature to pulse an associated circuit during said time interval.

2. In a time pulsing relay, an inductance coil having connection means to at least three points thereon, means for energizing a, first portion of said inductance coil by connection of a current source across two of said points whereby said in- 1 ductance coil is initially magnetically polarized, means for energizing a second portion of said coil by connecting one of said two points and said third point to said energy source, the inductive relationship of said portions being such that energization of said second portion effects a magnetic ux in said second portion of opposite po larity to the initial polarity of said first portion, including armature means responsive to magnetic flux of said inductance coil and adapted to be displaced by energization of said first portion and to be reversely displaced by initial transitory energization of said second portion and to resume initial displacement upon continued energization of said second portion and means responsive to said armature displacement cycle to pulse an associated circuit, said displacement cycle occurring in a time interval predetermined by the induct" ance ratios of said portions.

3. In a device as set forth in claim 2 wherein the inductive relationship of said coil portions is such that the flux of said second portion is of substantially greater intensity whereby the resultant ux of said inductance coil is reversed in polarity relative said initial polarization,

4. In a time pulsing relay, an inductance coil, means .comprising connections thereto for energizing a first section of said inductance coil by connection to a current source whereby said inductance coil is initially magnetically polarized, means comprising connections on said coil for energizing a second section thereof by connecting to an energy source, the inductive relationship of said sections being such that energization of said second section effects a magnetic flux in said coil of opposite polarity to the initial polarity thereof, including armature means responsive to magnetic ux of said inductance coil and adapted for normal displacement by energization of said first section and to be reversely displaced by initial energization of said second section and to resume normal displacement upon continued energization of said second section, and means responsive to said armature displacement cycle to pulse an associated circuit, said displacement cycle occurring in a time interval predetermined by the inductance ratios of said sections.

5. In a device as set forth in claim 4, includ-y ing means for predetermining said time interval, comprising connection means at a plurality of points on said inductance coil for selective connection to said current source to vary the in ductance ratio of said portions.

6. In a device as set forth in claim 1J including manually selective connecting means on said coil for varying the inductance ratio between said bucking and holding coils to predetermine said time interval.

7. In a device as set forth in claim 2, wherein said inductance coil is wound in layer form in such a manner that said first portion is at the exterior of said winding whereby heat due to energization of said rst section has access to the surrounding atmosphere for dissipation.

8. In a time pulsing relay, an electromagnet comprising a holding coil and a bucking coil, an armature magnetically responsive to said electromagnet for displacement relative thereto, means for impressing a continuous E. M. F. on said holding coil for energization thereof to displace said armature, means including a key for energizing said bucking coil upon closing of said key whereby said holding coil has an opposing E. M. F. transitorily induced therein operative to release said armature by reducing the uX intensity of said holding coil, the steady state resultant flux of said coils being operative to reattract said armature, means associated with said armature for pulsing an associated circuit during the time interval from release to reattraction of said armature, opening of said key being operative to deenergize said bucking coil whereby a supporting E. M. F. is transtorily induced in said holding coil, the resultant flux of said coils being transitorily weakened in intensity to release said armature, said armature being reattracted by said holding coil flux after a time interval from the instant of release, said time intervals being determined by the inductance ratio of said coils, said bucking coil having an inductance value exceeding that of said holding coil.

LOUIS A. SCHULZ.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS

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