US2668208A - Sensitive relay - Google Patents

Description

Feb. 2, 1954 LAMB r 2,668,208

SENSITIVE RELAY Filed Sept. 15, 1951 2 Sheets-Sheet l ANTHONY/f. LAMB AND ELMER 6. DEMOTT INVENTORS ATTO EYS 1954 A. H. LAMB ETAL 2,668,208

SENSITIVE RELAY Filed p 1 2 Sheets-Sheet 2 u I I; 5:: 8, Y a 74 75 T I/ I I I I I l :2 Wi mm! I.

V I I j I, 6'0 1 36 I 2 a I ANTHONY H. LAMB AND 40 37 40 ELMER 6. DE M077 INVENTORS #LIO v BY 2a Arm 5 Patented Feb. 2, 1954 SENSITIVE RELAY Anthony H. Lamb, Hillside, and Elmer G. De Mott, Chatham, N. .L, assignors to Weston Electrical Instrument Corporation, Newark, N. J a corporation of' New Jersey ApplicationSeptember 15, 1951, SerialNo. 246,726

10 Claims. (01. 200-110) This, invention relates to sensitive relays and more particularly to sensitive relays of the magnetic contact-type.

Relays of the type contemplated by this invention include a movable contact arm carrying a, contact in the form of a magnetic. rider for cooperation with a stationary contact constituted by a. small magnet. When the relay arm moves toward, the stationary contact the rider comes into the. field ofv magnetic influence of the magnet and is attracted thereto to provide a good, firm contact closure. In general, the magnetic contact so established requires some mechanical means for separating the rider from the magnet a the movable coil of the relay is incapable of generating sufficient torque for this purpose.

In prior relays of this type the stationary contact. comprises a small permanent magnet suitably mounted to provide electrical isolation between the magnet and other parts of therelay. While such design has proven. satisfactory for many applications, the manufacture of the permanent magnet and the assembly thereof in a relay is rather costly and does not lend itself to the production of inexpensive relays. The present invention is directed to a relay design emplaying the desirable features of a magneticcontact relay but, which is of simple-construction and which is adapted for the production of low cost relays. Specifically, the stationary contact com.- prises a soft-iron member disposed in the vicinity of the. relay magnet such member being adjustably fastened to the relay base. By reason of its position. in the magnetic field of the relay magnet such member becomes, magneticat its ing, a. ready means for altering the deflection characteristics of the relay coil.

A relay made in accordance with this invention includes numerous other features directed toward the Provision of a small, low cost, high quality relay. The individual relay components are all supported from a common base made of insulatin material, and are secured in position by novelv means that also serve as terminals by which the relay canv be connected into an external circuit. The relay case itself is. of simple construction and consists of. two, parts, a. base carrying the relay components, and acover car- III rying a simple mechanical arrangement for separating the relay contacts.

An object of this invention is the provision of a permanent-magnet, movable-coil relay of the magnetic contact type wherein the relay contacts are actually made of a low reluctance magnetic material such assoft-iron.

An object of this invention is the provision of a permanent-magnet, movable-coil relay of the magnetic contact type wherein the stationary contacts comprise adjustable soft-iron members having portions lying in the magnetic flux field of the primary magnet of the relay.

An object of this invention is the provision of a sensitive relay comprising a permanent magnet core supported between the legs of a nonmagnetic U-shaped bracket, a movable coil pivotally mounted between the legs of the said bracket and rotatable about the core, soft-iron members disposed on opposite sides of the core and spaced from the movable coil, a pointer or contact arm carriedby the coil, and a magnetic material rider secured to the end of the pointer, said rider adapted to contact each of the said soft-iron members upon rotation of the movable coil.

An object of this invention is the provision. of a sensitive relay comprisin a base of insulating material, a non-magnetic U-shaped bracket secured in upright position to said base, a cylindrical permanent magnet core secured between the legs of the U-shaped bracket, a movable coil pivotally mounted between the legs of the U-shaped bracket and rotatable about the core, a pair of soft-iron members secured to the base and disposed on opposite sides of the said core, each of said members being spaced from the coil and including an elongated end, a contact arm carried by the coil, a magnetic material rider carried by the end of the contact arm, a cover member cooperating with the base to form a closed case, and a finger-operable mechanism carried by the cover and adapted upon operation to contact the said contact arm.

These and other objects and advantages will be apparent from the following description when taken with the accompanying drawings. The drawings are for purposes of illustration and are not to be construed as definin the scope or limits of the invention, reference being had for the latter purpose to the appended claims.

In the drawings wherein like reference characters denote like parts in the several views:

Figure l is an exploded view, in isometric,

arm 28.

.tified by the numeral 3!.

showing the major components of a relay made in accordance with this invention;

Figure 2 is a cross sectional view taken along the line A-A of the base shown in Figure 1;

Figure 3 is a cross-sectional view taken along the line B-B of themcunting bracket shown in Figure 1;

Figure 4 is a side view showing the mounting bracket and permanent magnet core mounted upon the relay base;

Figure 5 is an isometric view showing the mounting bracket and the two soft-iron contact members mounted on the relay base;

Figure 5 is a cross-sectional view taken along the line C-C of Figure 5 and showing how one of the screws employed to secure the soft-iron contact members to the base also serves as a connection terminal;

Figure '7 is an isometric view of the relay cover that carries the finger-operable contact-resetting mechanism;

Figure 8 is a front view of the relay with the cover in place, the cover being shown in crosssection and the resetting mechanism being omitted for purposes of clarity; and

Figures 9 and 10 are fragmentary illustrations intended to facilitate an understanding of the operation of the resetting mechanism.

Referring now to Figure 1, the relay base l0, made of a suitableinsulating material such as a plastic, is a unitary member provided with a shoulder H and raised portion 52. The base is provided with the threaded inserts l3, l4, l5 and IS, a pin-type terminal ii, a hole H3, and a recessed hole Hi, the purpose of which will befitted into suitable holes provided for this purpose.

, The relay mechanism comprises a U-shaped bracket 29 having a transversely-magnetized, permanent magnet core 2! secured thereto. It may here be stated the bracket 29 is made of a non-magnetic material, such as brass, and forms no part of the magnetic flux circuit. A wire wound movable coil 23 is pivotally supported between the legs of the U-shaped bracket, such coil being provided with conventional pivots rotatable within jewel screws, one such jewel screw 24 being visible in the drawing. As is well known in this art, current is conducted to the movable coil by a set of spiral springs 25, 25, each spring having an inner end secured to the adjacent pivot base and the outer end secured to an abutment. In the present case, the upper spring 25 is secured to the abutment 2'! which is rotatable in response to rotation of the conventional zero-corrector The abutment 21 and arm 28 are grounded to the bracket 25]. In such case, the lower spring 26 must be electrically insulated from the bracket. This is accomplished by insulating the lower abutment 39 from the bracket 20 as shown more clearly in Figure 3 which is a cross sectional view taken along the line BB of the lower leg of the bracket, shown in Figure 1. In Figure 3, the lower leg of the bracket is iden- The abutment 3E3 is secured to the leg 3! by an internally-threaded rivet 32 and the abutment is insulated from the bracket leg by a combination of the insulator bushing 33 and insulator washer 34, as shown. The outer end of the lower spring 26 (Figure 1) is soldered to the inner end 35 of the abutment 4 30 (Figure 3). It is here pointed out that the recessed hole is, in the relay base It is designed to accommodate the head of the rivet 32 and the insulating washer 34 when the relay mechanism is secured to the relay base, as will be explained with reference to Figure 4, below.

With further reference to Figure 1, the relay mechanism includes a pointer, or arm, 36 that is secured to the movable coil 23 said arm carrying a soft-iron rider 3'? on its free end. As shown, the mechanism is complete in itself and can be assembled and adjusted outside of the relay case. All parts of the mechanism are readily visible and accessible thereby promoting reduced manufacturing costs.

The stationary contacts of the relay comprise the soft-iron members 40, 40' having reverselybent base sections 4!, 4!, respectively, each base section provided with a air of holes. The holes 42, 43, in the member 40 are spaced to aline with the threaded inserts I5, It in the relay base 10 and such member 58 can be secured to the base by a threaded post 44 and a screw 55, as will be described in detail hereinbelow with reference to Figures 5 and 6. The other soft-iron member 4| is likewise mountable on the base it by the post 44 and screw 45'.

Reference is now made to Figure 4 which is a side view showing the relay mechanism mounted on the relay base; the movable coil, springs, etc. being omitted for purposes of clarity. In this view the spacer member 22 is shown between the magnet and the bracket wall. The use of such specific spacer member, which can be soldered or welded to both the magnet and the bracket, is optional. The magnet can be spaced from the bracket wall by forming a longitudinal detent in the bracket. The U-shaped bracket 26 is secured to the base It by a screw '50 and a threaded terminal 5| passing through the holes l8, 59 shown in Figure 1. The screw 58 is threaded into the internally-threaded rivet 32 (see Figure 3) and the terminal 51 is threaded into a threaded hole 52 in the lower leg of the bracket (see Figure 1). Therefore, the lower leg of the bracket rests flat upon the surface of the base and the mechanism is secured firmly thereto. By soldering a lead 53 between the pin terminal I! and the lower abutment 38, it will be apparent the movable coil of the relay can be connected to an external circuit by means of the pins l1 and 5| (since the lower coil spring is connected the abutment 3i and the upper coil spring is grounded to the bracket 20). It is also quite clear that the terminal l! and the lead 53 can be omitted if the screw so be replaced by a threaded terminal pin similar to the pin 5 l. Such threaded terminal pin will serve the dual purpose of securing the bracket to the base and as a means for connecting the ungrounded side of the movable coil to an external electrical circuit.

Reference is now made to Figure 5. The relay mechanism is shown mounted on the base 10, as just explained; the movable coil, springs, abutments, etc., being omitted. However, the relay movable arm 36 and the iron rider 3? are shown in proper position relative to the stationary contact members iii, 4!! now shown secured to the base Iii. As shown in Figure 6, which is a cross sectional view taken along the line C--C of Figure 5, the lower, threaded end of the post 45' is threaded into the insert l3 and the screw 45 is threaded into the insert I i it being noted that the reduced-diameter pin section 55 of the screw extends through the insert to provide a terminal for connecting- .the' softairon. member; 4.0:! to. an 6190: triiialfcircuit; The holes: 42', 453:; (see. Figure; 11):. in the. base section 41. ofizthesoitr-ironimember Mfr-are. enlarged; or clearance holes whereby the position ofithemember can be. adjusted relar tive to the magnetic core 21:. The. other soft,"- rron. member 43; is. secured, similarly, to. the base H] :andll-i'es diai-netricall-y opposite: to the member 401' with respect. to: the core-'25. In the illustrated construction the screw has; a. reduced diameter pin section passing through the insert. 1:4.to. serve as an external connection terminal. while/the threaded. end of the post M1 terminates within the. threaded insert I31. To further reduce the cost of.- the relaya. somewhat reverse arrangementais. employed. Specifically, the post: 4.4," in: cludes an integral pin section extending; from the. externally-threaded. end,v such, pin section passins through the insert I13: to, serve, as the ex: ternak connection. terminal. screw: 55.- and insert. 84; can be omit-t In;- the event. a more. positive arran ement. desired to prevent possible: rotation. f th member is abo t the, axis. oi the. post. 44; the relay; base. can; be provided. an. integral recess having one or more; side walls abutting against the edges of the base section of the. member at.

It is; to be noted. the: soft-iron members t, it are. spaced; from the magnet core. Essentially,

the coreis a free. magnet in space and the men J Ways, namely, by the thickness and size. of the.

members 48,, it, by the spacing of one or both of these. members withv respect to. the core, and by appropriately shaping that portion of these members lying within the ran e. of, rotation of the movable coil. In. the. latter case, for example, the 4..

body of one or both of the. soft-iron. members 40, 40 may be arcuate instead of flat asshown. Since the members, 40., 4t" lie within the magnetic flux field, lines of flux, will. emanate from the edges thereof and such flux linesserve. to attract the soft-iron rider BIcarried by the relay pointer. 35.. In a rel y constructed. as shown, the. magnetic attraction holding. the rider't'o. the edge or the stationary soft-iron member is. s'uiiicient tov prevent separation oi the. contactsjeven when the relay is suh,iepcted to severe, mechanical; shock.

It. will be apparent from the. description. thus far presented that the. individual parts ofthe relay are of. simple. construction, a e e sily. as,-' sembled in proper relative. position, that the parts carried by the relay base constitute. a complete, operative relay with the exception of a suitable mechanicalmeans tor separating thev iron rider from either [of the stationary contacts.

The resetting mechanism of our relay iscarried y the relay Coven. as shown in F gu 7- The cover 6c is made of a transparent plastic and has integral ears GI extending irom'opposite sides, said ears serving as. a means for mounting. the complete relay on panel or other apparatus. The. top of the cover carricsa rotatable zero adluster screw 62-..05 more or lessconventional censtructi-on..- Rotation of, the screw c2, impartsan oscillatory movement. tgthe, pin; .63, which engages a suitable. arm. extending. from. the. ten of he. relay Insuch s n the.

6 mechanism as willhe explained hcreinhelow with referencezt'o Figures; Thetop surfaceot}, the cover is also provided with 100. 64 0 a ommo date suitable screws. for fastening; the cover in. position over the; relay base. The contact13esetting mechanism comprises the flat rod or plate fiihaving an. integral tip 6.5 of rectangular cross, section, which extends througha rectangular slot in the. cover wall. Surrounding the; tip BB -is-a helical compression, spring 61; having one endin1 contact with the inner wall of the cover and; the; other end abutting against the resulting shoulder of the plate 2'55, as shown. A suitablewasher 68 secured to the enctcf thev tip that lies cut side of the cover from. which; it isapparent the spring 61 applies a mechanical bias to the plate. 5.5: direction such that the washer fit'normallyg abuts against the cover 60. In such,norma1-pQsi-. tion of the resettingrmechanism a substantial, portion of the end 63 of? the plate; 65 extends, ou -l wardi ofthe cover through a, suitable rectangus. lar slot in the cover side wall. Finger pressure applied to the end 6.9 of the plate willcause the plate 55 to move along the axis-oi the spring 61;

' asthe said-spring is compressed. Release of such pressure. permits the spring to returnthe plate. to the position shown in Figure Since the end 59 and tip 55 arev of rectangular cross section. each operable with'an appropriate rectangular slot in the side wall of the cover,; a. smooth. monoplanar movement of the plate 5.5 is assured. shown in the drawing, the upper side of; the plate 5.5; may be provided with a recess lit in the event; the upper side edge of the plate 6.5: is designed to,

contact the-inner surface ofthe covertop, In;

such case only the edges "H and; ll of the plate will rub against the cover top during operation or the. reset mechanism, thereby: red cing the. iii-iction between: the plate and cover top. Moreime portantly; the plate 65 is; provided withanother recess 13 resulting in; the downwardly-depending edges 14', 1.5. When the cover '69, is secured in position. on. the relay base the resetting; mechanism will occupy a. position such that the. relay: movable. arm operates within the recess l3: and is; subject to contact by the edge M.- or 15 for re setting purposes as will. bedescribed with reference: to Eisureseand 1c. Y Figure 8 illustrates the relay with the cover in place. Forpiirposes of clarity the, cover 5?), is shown in crossv section and the spiral springs andabutments of the mechanism have been omitted. It willbe noted: open. end oi the cover B l-rests. upon the lip H of: the relay base i-J and the cover iS'l secured in; p sition by the screws-8 threaded; into the upper ends of the posts. 44; 6.4. The-tip S3. of: the zero adjuster mechanism extendsthrough a slot in the zero-adjuster arm 28- where bythe normal, or zero current, position, of. the movable coil 23 can be altered by rotation-0t the screw 6.2.

"Reference is new to. Figures 9 and 10 which are fragmentary 'views taken from the front; of theI instrument. In- Figure 9; the contact resetting mechanism. is shown in its normal position, that. is, the washer 5t abuts-against. the cover side wall. The movable arm 35 of, therel-ay mechanism rotates about the axis a---c (defined by the pivots of the movable coil) and the plate 3.5 is so positioned that the downwardly-depending edges M, intersect the plane in which the upper section of the a rotates. Consequently, when the plate.- .s inits normal position tl e. extent of. rotation of the arm. 3.5182113}?- i'ted; by the edges 14, is. Under such condition.

the iron rider 3'! is free to contact the soft-iron member 49 but not the member 60'. Now, if the plate 65 be moved inwardly of the cover 50 the edge 14 will move the arm 36 causing a separation of the rider 3'! and the member 40. The extent of linear movement of the plate 65 is such that the rider 3'! is moved out of the magnetic field of influence of the member 40 whereby the position of the arm 36 will be controlled by the current flowing through the movable coil of the relay upon a subsequent return of the plate 65 to its normal position.

The innermost position of the plate 65 is shown in Figure 10. In such position of the plate the edge 14 prevents contact of the rider 3! with the stationary contact 40 while permitting contact between the rider and the contact 40. Upon closure of the contacts constituted by the rider and the member 40' contact separation is accomplished when the plate 65 is returned to its normal position under the action of the spring 61, as shown in Figure 9.

It will now be apparent the plate 65 serves two purposes, namely, to condition the relay so that the iron rider can contact only one or the other of the stationary contacts and to separate the contacts so made upon selected movement of the reset mechanism. A relay of this construction is adapted for use in on-ofi control systems wherein a closure of one set of contacts results in, say, an energization of a load device after which such contacts are opened by manual or electromagnetic movement of the resetting plate. Upon such energization of the load device the relay is conditioned for 'a closure of the other set of contacts that results in a de-energization of the load device.

Having now described our invention the many features thereof are apparent. The individual parts are of simple construction and easy to as semble and replace. The stationary contacts are made of a low reluctance magnetic material positioned and shaped to control the magnitude and distribution of the magnetic fiux field within which the movable coil operates. These same contacts become magnetized at their cont-actmaking ends to provide a good magnetic contact type relay. Further, these contacts are secured to the base of the relay in such fashion that their position relative to the permanent magnet coil may be adjusted to alter the deflection characteristics of the relay. At the same time the means securing the stationary contacts to the base serve as the means for connecting them into an external electrical circuit thereby eliminating separate connection straps, terminals, etc. While the pin type connection terminals extending from the lower surface of the base can be used as soldering terminals for connecting the relay into a network such pin terminals, preferably, are designed to provide a plug-in type relay. In the latter case, the pin terminals establish friction contact with suitable, hollow terminals carried by a socket, the arrangement being similar to the conventional radio tube-socket combination. 'Still further, a simple, inexpensive reset mechanism is provided which not only separates the relay contacts but also conditions the relay properly for the next operating cycle. These features are attained in a relay of exceptionally small size and without sacrifice of any desired operating characteristics found in conventional relays of this class.

While we have illustrated and described a simple D.-C. version of the relay the invention is not limited thereto. The relay can be used on 8 A.-C. currents by incorporating therein a suitable rectifier comprising a series of asymmetricallyconducting discs. Such discs, as well as resistors, can be disposed within a suitable recess provided in the relay base, particularly in the raised portion I2 as shown in Figure 1.

Numerous changes and modifications of the individual parts and their cooperating assembly will present themselves to those skilled in this art without departing from the spirit and scope of the invention as set forth in the following claims.

We claim:

1. In a relay of the type including a pair of stationary contacts and a cooperating movable contact for controlling an electrical circuit, the combination of a base of insulating material, a U-shaped bracket secured to the base, a permanent magnet core secured to the bracket and disposed between the legs of the bracket, a movable coil pivotally supported by the bracket and rotatable about said magnet core, a movable arm secured to the movable coil and having a free end normally extending beyond the range of magnetic influence of the magnet core, a rider of magnetic material carried by the free end of said movable arm, and soft-iron members secured to the base and electrically insulated from each other and the bracket, said members being disposed on opposite sides of and spaced from the movable coil and magnetic core and including portions disposed in the field of travel of the said rider, the said rider and soft-iron members constituting the contacts for controlling the electrical air-- cuit.

The invention as recited in claim 1, wherein the said soft-iron members comprise a base portion secured to the relay base, an offset central portion spaced from the movable coil and a pro- J'ecting end section lying in the path of travel of the rider.

3. The invention as recited in claim 1 wherein the soft-iron members are adjustably secured to the base.

4. The invention as recited in claim 1 wherein the said soft-iron members are secured to the base by a threaded member having a pin section proiecting from the relay base.

5. A relay comprising a base of insulating material; a U-shaped bracket of non-magnetic material disposed in upright position on the base; a threaded, pin type terminal member passing through a hole in the base and into a threaded hole in a leg of the bracket, a movable coil carrying a pointer and pivotally supported between the legs of the bracket; a rider of magnetic material carried on the end of the pointer; a trans versely-magnetized, substantially-cylindrical permanent magnet core secured to the base of the bracket and disposed within the movable coil: a soft-iron member having an end section disposed in the path of travel of the said rider, a mid-section spaced from the movable coil and magnetic core, and a base section adapted for flush contact with the relay base; a pair of holes in the base section of the soft-iron member; internally threaded inserts in the relay base said inserts alined with the holes in the base or the soft iron member; and fastening members passing through the holes in the base section of the soft-iron member and into the inserts.

6. The invention as recited in claim 5 wherein one of the said fastening members includes an integral, reduced diameter extension passing through the associated insert.

7. The invention as recited in claim 5 wherein one of the said fastening members is a post extending upwardly in spaced relation to the said soft-iron member.

8. The invention as recited in claim 7 in combination with a cover having an open end in contact with the relay base; a hole in the cover; and a screw member passing through the cover hole and threaded into an end of the post.

9. The invention as recited in claim in combination with a cover; means removably securing the cover to the relay base; and an externally-operable reset rod supported by the cover for linear movement within the cover, said rod adapted to contact the said pointer upon a predetermined movement of the rod.

10. A sensitive relay comprising a base of insulating material provided with a shoulder, a pivoted movable coil rotatable about a substantially cylindrical, transversely magnetized permanent magnet; a U-shaped bracket supporting the movable coil and magnet in operative position; means securing a leg of the bracket to the base whereby the bracket extends upwardly from the base; a pointer secured to the movable coil and carrying a soft-iron rider; a pair of softiron members disposed on opposite sides of the permanent magnet and spaced from the movable coil and magnet, each said member including a section adapted for contact by the said rider; means securing the said soft-iron members to the relay base said means including a. pair of posts extending upwardly from the relay base; a cover having an open end disposed on the shoulder of the relay base and including a pair of holes alined with the said posts; screws passing through the cover holes and into the said posts; a transversely-movable reset rod having ends extending through apertures in opposed side walls of the cover; a spring biasing the said reset rod to a normal position; a recess in the wall of the reset rod said recess being defined by side walls adapted to engage the said pointer to separate the iron rider from either of the said soft-iron members.

ANTHONY H. LAMB.

ELMER G. DE MOTT.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 989,420 Reichel Apr. 11, 1911 1,958,713 Reyman May 15, 1934 2,014,387 Lamb Sept. 17, 1935 2,102,409 Faus Dec. 1 1, 1937 2,203,727 Herbst June 11, 1940 2,262,504 Lamb Nov. 11, 1941 2,565,312 Lamb Aug. 21, 1951 FOREIGN PATENTS Number Country Date 362,116 Great Britain Dec. 3, 1931

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