US2902565A

US2902565A - Electro-magnetic relay

Info

Publication number: US2902565A
Application number: US638420A
Authority: US
Inventors: Angold Edward Barnabas
Original assignee: Plessey Co Ltd
Current assignee: Plessey Co Ltd
Priority date: 1956-02-13
Filing date: 1957-02-05
Publication date: 1959-09-01
Anticipated expiration: 1976-09-01
Also published as: FR1166274A; DE1071230B; NL105252C; NL214493A

Description

Sept. 1, 1959 E. B. ANGOLD ELECTRO-MAGNETIC RLEAY Filed Feb. 5, 1957 v 11111 1| n 2 8 T R l/ T 4 2 a n M United States Patent f) 'ELECTRO MAGNETIC RELAY Edward Barnabas Angold, Ramsden Heath, England, assignor to The Plessey Company-Limited, Ilford, England, a British company Application February '5, 1957, Serial No. 638,420

Claims priority, application Great Britain February 13, 1956 7 Claims. (Cl. 200-104) This invention relates to electromagnetic relays and has for an object to provide an improved relay of the kind, hereinafter called the kind'specified, in which a substantially. fiat armature, extending longitudinally of the relay winding, is arranged between the relay winding and the contacts to be operated.

in a previously known electromagnetic relay inwhich a substantially flat armature extends longitudinally of the relayvwinding and is arrangedbetw'een the relay winding and the contacts to be operated, the armature co-operates with all end of the core which is turned up and back over the coil to constitute a pole piece, while the armature is pivoted by edge contact on a yoke which extends forwardly over the coil from the rearward end of the core towards the pole piece. The magnetic flux thus passes from the yoke to the armature through the edgecontact connection, and back to the pole piece and the armature projecting overthe latter, vwhile no appreciable flux passes through the part of the armature beyond the line of edge contact.

According to the present invent-ion two pole pieces of a relay of'the kind specified extend inwardly from the two ends of the core of the relay winding, and the armature is 'pivotally movable about a transverse axis at or near its centre, one end of the armature extending at the innerside of one of the pole pieces, and its other end extending at the outer side of the other pole piece. As a result the polar moments exerted upon the armature by the magnetic attraction of the two poles act additively, and each passage of the flux between the stationary core :structure and the armature is utilised to contribute to the available contact-actuation force, so that the relay will develop a great actuation force in relation to its size.

In one particular form of the relay according to the invention the armature is provided with projecting pin elements; A bridge member or structure, supported on the'inner'pole piece and extending across the pole piece at the outerside of the armature serves to support a'stack of contact-springs extending along the outerside of the core-and-armature assembly. The stack of contact springs and the bridgepiece are secured by screw means extending through suitable apertures inthe armature, in the bridge member and in or between insulating'spacers separating thecontact blades, and each' side ofthe bridge member or structure has a projection extending to, and supported, preferably under slight elastic deformation load, against the inner surface of the other pole piece. These projections areformed with recesses attheir outer side, in which the two pin elements'of the armature are respectively supported'for pivotal movement. The pin elements may be of square or rectangular cross-section and rest in similarly shaped recesses to obtain low friction loss' and low cost ofmanufacture.

According to a modification the projecting pin elements of the armature of the bridge and the recesses in the projections may be omitted. A thin flexible sheet of non- Patented Sept. 1, 1959 ferromagnetic material is secured to the outer surface of the inner pole piece and to the inner surface of that part of the armature which faces the other pole piece. Pivotal movement of the armature is possible by flexing of this sheet round the edge of the inner pole piece. In order to reduce stress in the sheet, this edge is preferably rounded with a suitable radius. The flexible sheet, in addition to hingedly connecting the-armature to the inner pole piece, also locates it by preventing any movement in the plane of the armature.

The armature actuates the movable'contact springs by one or more actuating pins or cards co-operating with the outer surface of the armature at the outer side of the other pole piece, which extend through apertures in the said other pole piece and aligned apertures of at least two contact spring blades or dummy blades, while 'being supported by a shoulder or the like on the surface of the spring to be actuated.

Excessive inward movement of the stationary and/ or movable contact springs is preferably prevented by one or more spacer pins or cards guided similarly to the actuating pins or cards by aligned apertures in two springs or similar blades, said spacer pins having shoulders supported on opposed surfaces'of at least one movable contact spring and a relatively rigid blade extending between said contact spring and the core and armature assembly. This relatively rigid blade may serve as a stationary contact blade.

Two embodiments of the invention will now be described in more details with reference to the accompanying drawings, in which:

Figures 1 and 2 are respectively a top plan view and a side elevation, partly in section, of one embodiment, and

Figure 3 is a side elevation of the armature and core assembly of the other embodiment.

Referring now first to Figures 1 and 2, the relay has a winding 5 surrounding a core 6 of magnetisable material one end of which is bent at right angles to form a shank 7, and the end of which is once more bent at right angles to form a pole piece 8 extending, at the outer side of the winding 5, substantially parallel to the core 6. A contact stack, generally referred to by reference numeral 9, is secured to the pole piece 8 by a screw 10, with the interposition of a bridge member 2, which is formed of nonmagnetic sheet metal blanked to appropriate shape and bent to an inverted U profile. The flanges 2a of the U-profile bridge member rest on the pole piece 8, while the web 2b, preferably reinforced by a transverse pressed ridge 2c, is spaced from the pole piece 8 by the flanges 2a. A second pole piece 13, constituted by a fiat piece of magnetisable material bent to approximate L shape, is secured with one of its limbs to the free end of the core 6, for example by riveting, while its other limb extends along the outer side of the winding 5, in a direction opposite to that of the pole piece 8, but at a slightly greater distance from the winding 5, for areason which will soon become apparent. The flanges 2a of the bridge member 2 are extended beyond the inner end of the Web portion 21b to form support brackets 20 which engage the inner surface of the second pole piece 13, the construction being such that when the screw 10 is tightened, the ends of the support brackets 2c are-pressed against the inner surface of the pole piece 13 between the respective ends of the web portion 2b and the pole piece 13. The support brackets 20 are each formed with an approximately rectangular cut-out 2d, and these cut-outs accommodate fulcrum pins 1b which project at opposite sides from a flat ferro-magnetic armature 1, which is thus pivotally supported on the bridge member -2-in such manner that one half of-the armature faces the outer surface of the pole piece 8, While the other half of the armature faces the inner surface of the other pole piece 13. The contact stack 9 comprises a flexible contact blade 14 carrying a contact block 15 constituting the movable contact of the relay, and two fixed

contact blades

16 and 17, respectively carrying the

contact blocks

18 and 19, constituting the stationary contacts. The inner fixed contact blade 16 is relatively rigid, while the outer fixed contact blade 17 is flexible similarly to the movable contact blade 14. A resilient auxiliary or dummy blade 20 is also provided in the stack. A spacer 4, having an abutment portion 4a against which the opposed surfaces of the

fixed blades

16 and 17 are supported, serves to maintain the

fixed contacts

18 and 19 at the requisite relative distance so that contact block 19 is clear of contact block 15 when the relay is in the illustrated, tie-energised position, in which contact block 15 rests against contact block 18 carried by the relatively rigid fixed blade 16.

When the relay windings are energised, magnetic flux will flow across the air gaps visible in the drawing, between the pole piece 8 and the lower side (in Figure 2) of the right-hand half of the armature and also between the pole piece 13 and the upper side of the left-hand side of the armature. The resulting attraction forces at both air gaps act additively, exerting a clockwise torque upon the armature about its fulcrum axis. This torque is utilised for moving, by means of an actuating card 3, the flexible blade 14 from the illustrated inoperative position, in which the contact block 15 is in contact with block 18, to the operative position, in which this contact is broken and contact block 15 instead makes contact with contact block 19 on blade 17. The actuating card 3 extends through aligned slots in the blades 14 and 2t), and has a shoulder 3a which acts upon the underside of the blade 14, While its lower end 3b co-operates with the upper surface of the left-hand half of armature 1. A second shoulder 30 of the actuating card 3 is supported against the lower side of the auxiliary blade 20, which blade provides a return force tending to restore the armature 1 to its illustrated inoperative position. Between the various contact springs clamped by means of the screw 10, insulating discs 21 are interposed. In the illustrated embodiment two sets of contact blades are provided, each with an actuating card 3 and spacer 4, one set at each side of the clamping screw 1%, but it will be readily understood that either a single set or more than two sets may alternatively be employed without exceeding the scope of the present invention.

Figure 3 illustrates a modified armature-and-core assembly; this may be equipped with a contact stack, spacers, and actuating pins which are identical with those shown in Figures 1 and 2, and which have been omitted in the drawing to simplify the figure. In this embodiment the pivotal connection between the armature 1 and the pole piece 8 which is integral with the core 6, is effected by means of a flexible sheet 11 of non-magnetic material which at one end is connected to the armature, for example by rivets 22, while the other end of the flexible sheet 11 is secured to the pole piece 8, for example by being clamped between the latter and the bridge member 12. In order to define more closely the Zone of flexure, a second line of attachment of the sheet to the armature is preferably provided by rivets or screws 23 fixed in the armature 1, preferably with the interposition of a clamping bar 24 at the back of the sheet 11. The bridge member 12 itself may be constructed similarly as illustrated in Figure 2, except that the recesses 2d provided in the bracket portions 20 of bridge member 2 are omitted in the bracket portions 120 of the bridge member 12.

What is claimed is:

1. An electromagnetic relay, comprising in combination, a core, first and second pole pieces associated with the core, a free end portion to each pole piece, the free end portions being turned inwardly to overlie the core and to face towards each other, on the same side of the core,

in separated relationship, a cradle-like bridging member blanked out from a single piece of non-magnetic material bridging the pole pieces, readily releasable means for securing the bridging member to one of the pole pieces so that the bridging member is held in contact with the other one of the pole pieces in such manner as to ensure accurate relative positioning of the pole pieces and an armature pivotally supported by the bridging member for balanced pivotal movement about a transverse axis, so that one end thereof is located between a pole piece and the core, and so that the other end co-operates with the remaining pole piece on the side thereof remote from the core.

2. An electromagnetic relay, comprising in combination, a core, a winding on the core, first and second pole pieces magnetically connected with the core, an end portion of each pole piece being turned inwardly to overlie at least a part of the winding so that the end portions face towards each other on the same side of the core with a gap between the end portions, a blanked out channelled member bridging the gap, readily releasable means for securing the bridging member to one of the pole pieces so that the bridging member is held against the other pole piece in such manner as to ensure accurate relative positioning between the pole pieces, a set of contact springs supported by said bridging member and secured thereto by the means securing the bridging member to said one pole piece and an armature pivotally mounted on the bridging member to be swingable between the gap with one limb of the armature located between a pole piece and the winding and with the other end of the armature co-operating with that side of the remaining pole pieces which is remote from the winding.

3. An electromagnetic relay, comprising in combination, a core, first and second pole pieces associated with the core, a free end portion to each pole piece, the free end portions being turned inwardly to overlie the core and to face towards each other on the same side of the core, in separated relationship, a member bridging the separation between the pole pieces, screw means for securing the bridging member to one of the pole pieces, a projection extending from each side of the bridging member, each projection extending to, and being supported against that surface of the other pole piece which is adjacent the winding so that when the bridging member is secured to the one pole piece slight elastic deformation is produced between the pole pieces, and an armature pivotally mounted on the bridging member to be swingable between the gap with one limb of the armature located between a pole piece and the winding and with the other end of the armature co-operating with that side of the remaining pole piece which is remote from the winding.

4. An electromagnetic relay, comprising in combination, a core, a winding on the core, first and second pole pieces magnetically connected with the core, an end portion of each pole piece being turned inwardly to overlie at least a part of the winding so that the end portions face towards each other on the same side of the core with a gap between the portions, a member in the form of blanked fiat material bent to a U profile bridging the gap, means for securing the bridging member to one of the pole pieces so that the bridging member bears upon the other pole piece in such manner as to produce elastic deformation between the pole pieces, and an armature pivotally mounted on the bridging member to be swingable between the gap with one limb of the armature located between a pole piece and the winding and with the other end of the armature co-operating with that side of the remaining pole piece which is remote from the winding.

5. An electromagnetic relay, comprising in combination, a core, a winding on the core, first and second pole pieces magnetically connected with the core, an end portion of each pole piece being turned inwardly to overlie at least a part of the winding so that the end portions face towards each other on the same side of the core with a gap between the end portions, a member, in the form of blanked flat material bent to a U profile and having a pressed stiifening ridge extending across the web of the U bridging the gap, means for securing the bridging member to one of the pole pieces so that the bridging member bears upon the other pole piece in such manner as to produce elastic deformation between the pole pieces and an armature pivotally mounted on the bridging member to be swingable between the gap with one limb of the armature located between a pole piece and the winding, and with the other end of the armature cooperating with that side of the remaining pole piece which is remote from the windmg.

6. An electromagnetic relay, comprising in combination, a core, a winding on the core, first and second pole pieces magnetically connected with the core, an end portion of each pole piece being turned inwardly to overlie at least a part of the winding so that the end portions face towards each other on the same side of the core with a gap between the end portions, a channelled blankedout member bridging the gap, readily releasable means for securing the bridging member to one of the pole pieces so that the bridging member is held in contact with other pole piece in such manner as to ensure accurate relative positioning of the pole pieces, a set of contact springs supported by said bridging member and secured thereto by the means securing the bridging member to said one pole piece, an armature pivotally mounted on the bridging member to be swingable between the gap with one limb of the armature located between a pole piece and the winding and with the other end of the armature co-operating with that side of the remaining pole pieces which is remote from the winding, at least one through aperture formed in the other pole piece, and an actuating card in said contact spring set, the card being engageable by the armature.

7. An electromagnetic relay, comprising in combination, a core, a winding on the core, first and second pole pieces magnetically connected with the core, and an end portion of each pole piece being turned inwardly to overlie at least a part of the winding so that the end portions face towards each other on the same side of the core with a gap between the portions, a member in the form of blanked flat material bent to a U profile bridging the gap, readily releasable means for securing the bridging member to one of the pole pieces so that the bridging member bears upon the other pole piece in such manner as to produce elastic deformation between the pole pieces, an armature pivotally mounted on the bridging member to be swingable between the gap with one limb of the armature located between a pole piece and the winding and with the other end of the armature co-operating with that side of the remaining pole piece which is remote from the winding, and a set of contact springs supported by said bridging member and secured thereto by the means securing the bridging member to said one pole piece.

References Cited in the file of this patent UNITED STATES PATENTS 2,422,986 Ring June 24, 1947 2,455,049 Edwards et a1 Nov. 30, 1948 2,510,157 Towner et al. June 6, 1950 2,664,478 Johansson Dec. 29, 1953 2,760,026 Horlacher Aug. 21, 1956