US3253095A - Electromagnetic relays - Google Patents

Description

y 4, 1966 w. J. RlCH ERT 3,253,095

ELECTRQMAGNETI C RELAYS Filed Aug. 30, 1963 2 Sheets-Sheet 1 ,34 as \F -29 INVENTOR Walter J. Richert ATTORNEYS May 24, 1966 w. J. RICHERT ELECTROMAGNETIC RELAYS 2 Sheets-Sheet 2 Filed Aug. 30, 1963 FIG.6.

INVENTOR Walter J. Ric hert ATTORNEYS United States Patent 3,253,095 ELECTROMAGNETIC RELAYS Walter J. Richert, Princeton, Ind., assignor to American g Iachine & Foundry Company, a corporation of New ersey Filed Aug. 30, 1963, Ser. No. 305,720 6 Claims. (Cl. 200-87) This invention relates to electromagnetic relays and, more particularly, to relays of the type in which the armature is retained in an actuated position by permanent magnet means.

Relays of this particular type have become known in the trade as magnetic latching relays. In the general type of relay to which this invention applies, a pivoted magnetic armature is actuated by an electromagnet motor, selectively to two actuated positions, and permanent magnet means is provided to retain the armature in at least one of the actuated positions whenever that position is attained. Such relays may comprise two actuating electromagnets and a single permanent magnet, as disclosed in US. Patent 2,955,174, issued October 4, 1960, to Walter J. Richert, or may be made with only a single electromagnet, as disclosed in US. Patents 2,941,130, issued June 14, 1960, to Josef Fischer et al., and 2,960,583, issued November 15, 1960, to Richard T. Fisher et al.

For many applications for such relays, particularly when the finished relay must be very small, it is highly desirable to employ only a single electromagnet, i.e., a single core equipped with one or more coils. However, because of the physical disposition of the single electromagnet, and the arrangements which are then possible for the armature, the permanent magnet or magnets, and the contacts, it has been difficult to construct a single electromagnet, permanent magnetic latching relay in such fashion that severe problems do not arise in both manufacture and operation of the relay. Normally, as in this invention, the armature is made to extend generally parallel to the axis of the core of the electromagnet. However, with the known constructions of relays of this type, it is difiicult to find adequate space for the various elements of the relay without exceeding the space requirements for the relay.

In the single electromagnet latching relays used in the past, it has been possible to maintain the length and width of the relay within certain predetermined space requirements. However, in the relays of Fisher et al., 2,960,583, and Fischer et al., 2,941,130, the height of the relay as measured in a direction perpendicular to the base is several times the width of the relay. The difficulty with these constructions is that the contacts, armature, permanent magnet, and coil are mounted, respectively, in superposed relation relative to the base.

In the type of latching relay that employs two electromagnets such as that of Richert 2,955,174, the height requirements could not be maintained because the cores of the electromagnets were disposed with their axes perpendicular to the base.

In the relay of this invention, the problem of minute space requirements has been solved by a unique arrangement of the various elements of this electromagnetic, permanent magnet latching relay that measures only A" in length, /8 in width and in height.

Another problem which was solved was that of establishing flux paths of optimum effectiveness for both the permanent magnet means and the electromagnet. By the unique arrangement of elements of the magnet circuit of this relay, the flux path for the electromagnet is substantially improved as is the efficiency of the permanent magnet means in establishing a circuit for magnetically latching the relay when the electromagnet is unenergized.

A general object of the invention is to devise a relay ice of the type described, involving only a single electromagnet as the actuating motor, which is free from the manufacturing and operational problems heretofore encountered with such relays.

Another object is to provide such a relay that is extremely small and is so constructed that the electromagnet, permanent magnet means, and armature are disposed in a plane parallel with and spaced from the plane of the base.

A further object is to provide a permanent magnet latching type relay, in which the permanent magnet'means is disposed outside the normal flux path of the relay.

A further object of this invention is to devise such a relay with a balanced armature that is extremely resistant to accidental switching at high levels of shock and impact.

Yet another object is to device a magnetically latched relay in which the flux path for the electromagnet is substantially independent of the flux path for the permanent magnet to improve the operating characteristics of the relay.

In order that the manner in which these and other objects are attained in accordance with the invention can be understood in detail, reference is had to the accompanying drawings, which form a part of this specification, and wherein:

FIG. 1 is a side elevational view of a relay constructed in accordance with one particularly advantageous embodiment of the invention;

FIG. 2 is a top plan view of the relay of FIG.1;

FIG. 3 is an end elevational view of the relay of FIG. 1;

FIG. 4 is a side elevational view looking toward the side of the relay where the coil is located;

FIG. 5 is a plan view of the contacts and base with portions of the relay removed for clarity;

FIG. 6 is a view in exploded perspective of the several components of the relay; and

FIG. 7 is a schematic drawing showing the magnetic circuits of the relay.

Referring now to the drawings in detail, the embodiment of the invention there illustrated comprises a base 1, a contact and terminal assembly 2 carried by the base, a motor structure 3 including a pivoted armature 4, and a bracket 5 that supports the motor structure. Although the relay is shown with the base horizontal and the motor structure above the base, it is to be understood that the relay is operative in any position with equal effectiveness.

Considering FIGS. 5 and 6, base 1 is seen to be a metal header in the form of a plate which has a flat major surface 6 that faces motor structure 3 and a flat major surface 7 on the side of the base opposite from the motor structure. Base 1 is rectangular, and has straight edges at sides 8 and 9 of approximately twice the length of straight edges at ends 10 and 11. At side 8- are two spaced apart recesses 12 and 13 which have a bottom wall 14 parallel to major surface 6 and a rear wall 15 parallel to the surface of side 8. Recesses 16 and 17, identical to recesses 12 and 13, are also provided at side 9 of the base. rear wall 15 of each recess, as by welding, so that a portion of the tongue projects beyond major surface 6 generally at right angles thereto. The recesses and tongues 18 provide mounting supports for securing bracket 5 to the base, as will subsequently be described.

Terminal and contact assembly 2 includes a plurality of terminal pins 19-28 that extend through a plurality of openings 29 in base 1. The pins are secured in place by being embedded in masses of suitable insulating material filling the openings 29, in the usual manner.

The arrangement of terminal pins on base 1 is such that pins 19-22 are disposed at the corners of an imaginary square formed by lines connecting the axes of ad- A flat tongue 18 is secured tojacent ones of the pins. Terminal pin 23 is disposed at the intersection of the diagonals of the imaginary square thus formed. At the other side of the base, the axes of pins 24-27 are similarly disposed at the corners of an imaginary square, with pin 28 at the intersection of the diagonals of that square. In addition, the pins at each side of the relay have their axes on the same straight line and are equidistantly spaced.

The terminal pins project a sufficient distance beyond major surface 7 of base 1 to permit plugging the terininals into a suitable socket (not shown), the ends of the pins being rounded to facilitate inserting same into the socket. The portions of the pins opposite the rounded ends project above major surface 6 of the base to provide supports for the fixed and movable contacts, and connecting pins for the electrical leads from the motor structure 3.

As best seen in FIG. 5, pins 19 and 20 support fixed bent leaf contacts 30 and 31 adjacent end 11 of the base, and pins 26 and 27 support fixed bent leaf con tacts 32 and 33 adjacent end of the base, each of the fixed contacts having bifurcated contact ends. Extending between fixed contacts 30 and 31 is a movable leaf-type contact 34 supported by pin 25. Fixed contacts 30 and31 coact with movable contact 34 to form a single pole, double throw switch. The space between fixed leaf- type contacts 30 and 31, where movable contact 34 projects between these contacts, is offset in a direction toward side 8 of the base, so that movable contact 34 can be moved from contact 30 to contact 31 without engaging the centrally located terminal pin 23.

The arrangement of fixed and movable contacts at end 10 of the base is the same as for the contacts adjacent end 11, and the space between fixed contacts 32 and 33 is also offset toward side 8 of the base, so that a movable leaf-type contact 35 secured to pin 22 can be moved from fixed contact 32 to fixed contact 33 without engaging the terminal pin 28.

Fixed contacts 31 and 32 are substantially identical, having free ends that terminate short of the free ends of movable contacts 34, 35 to leave exposed surfaces on the sides of the movable contacts that face toward side 8 of the base. These exposed surfaces are provided for engagement with suitable pushers to armature 4 to operate the contacts.

As best seen in FIG. 6, contacts 30-35 are leaf spring type contacts of substantially similar width disposed in a plane spaced slightly above major surface 6 of base 1.

Motor structure 3 is fixed to bracket 5, which in turn is secured to base 1. Motor structure 3 includes an elongated electromagnet 36 comprising a cylindrical core 37 surrounded by two coils .38 and 39. The coils are wound on suitable insulating bobbins in end-to-end relation with the ends 40 of the core projecting beyond the ends of the bobbin. Ends 40 are turned to a smaller diameter than the body portion of the core to provide a cylindrical tip that projects axially at each end of the core from a transverse annular shoulder 41. There is secured to each exposed end 40 a flat magnetic member 42, the members 42 extending transversely of the core and parallel to each other. Members 42 are identical, each including a circular portion 43 of a diameter approximately equal to the diameter of coils 38 and 39. Each circular portion 43 has a centrally located bore 44 through which the ends 40 project when the members 42 are placed on the core and moved axially toward the coils into engagement with annular shoulders 37. The members 42 are then secured to the core by mechanically deforming the exposed tips of ends 40. Each member 42 also includes an integral rectangular portion 45 which extends away from the core to terminate in a straight end edge 46. Rectangular portions 45 are aligned with each other axially of the electromagnet, so that end edges 46 lie in a common plane.

A pair of identical permanent magnets 47, 48 which are rectangular in side elevation and transverse cross section are disposed between the free ends of rectangular portions 45, the magnets each having an end engaged with an fixed to the end portion of a different one of rectangular portions 45. Magnets 47, 48 lie in a common plane parallel to the axis of core 37 of the electromagnet and are of such length that their adjacent ends are spaced apart. A rectangular member 49 of a magnetic material fills the space between the adjacent ends of the magnets, the rectangular member being fixed to the adjacent ends of the magnets. The rectangular member has substantially the same height as the magnets but is slightly thicker so that a face 50 projects beyond the adjacent surfaces of the magnets in a direction toward the electromagnet, the surfaces on the sides opposite from the electromagnet being in a common plane to form a smooth surface along that side.

Magnetic members 42 are of such length, as compared to the diameter of the coils and the thickness of the magnets, that there is a substantial space between the magnets and the coils to accommodate pole pieces 51 and 52, and the armature. The pole pieces are each L-shaped and of rectangular cross-sectional configuration. The pole pieces are disposed with a short leg 53 parallel with and fixed to rectangular portion 45 so that a leg 54 extends parallel to the axis of the coils and adjacent the side thereof to provide exposed pole faces 55 and 56 projecting perpendicularly from opposite ends of the electromagnet. Pole faces 55 and 56 are spaced from the permanent magnets a distance sufficient to accommodate the armature. Ends 57 of short legs 53 have spaced apart tips on each side of a concave portion 58 (FIG. 3), the tips only abutting the permanent magnets adjacent the ends of the magnets with the concave portion spaced from the magnet. The concave portion 58 is effective to prevent ends 57 of legs 53 from shunting a portion of the permanent magnet. Such shunting, which is effective to decrease the effective length of the permanent magnet, and hence the strength of the flux produced by the magnet, is essentially avoided by this construction. Thus, core 37 of the electromagnet, and magnetic members 42, cooperate to define a rigid magnetic structure which can be considered to be generally in the form of a shallow U, with magnetic members 42 defining the legs of the U and the pole pieces 51 and 52 presenting exposed pole faces 55 and 56 parallel to the base of the U in facing relationship with the permanent magnets. The permanent magnets 47 and 48 and rectangular member 49 combine to form a magnetic structure 59 that extends between the legs of the U and is parallel to the base of the U. With magnetic structure 59 in position between the ends of members 42, it is apparent that a rectangular flux path is provided, the members comprising the rectangular flux path being in a plane parallel with the base. Therefore, it is apparent that the pole faces 55 and 56 are located between permanent magnets 47 and 48 and coils 38 and 39 with the legs 54 that define the pole faces being immediately adjacent to the sides-of the coils.

Bracket 5 is formed from sheet metal that is preferably nonmagnetic. The bracket includes a rectangular frame having sides 60 and 61 and ends 62 and 63, each of the ends being curved a short distance from side 60 to conform to the configuration of magnetic member 42 so that the rectangular magnetic structure defined by the core, magnetic structure 59, and magnetic members 42 is disposed in a plane parallelwith and spaced above base 1. A pair of legs 64 project toward the base from side 60 and another pair of legs 65 project toward the base from side 61 at the opposite side of the bracket. The legs are generally triangular and terminate in rectangular tips 66 which are so spaced that they align with and are disposed in recesses 12, 13 and 16, 17 in such a manner that the inwardly facing surfaces of the legs engage tongues 18, these surfaces being secured to the tongues 5. by welding. Due to the curvature of ends 62 and 63, side 60 of the bracket is disposed in a plane between the base and the plane of side 61, and hence it is apparent that legs 64 are slightly shorter than legs 65. Adjacent the sides of rectangular tips 66 are edges 66 of legs 64, the edges abutting major surface 6 of the base to properly space the motor structure from the base. Extending toward side 60 from the center side 61, in a plane parallel with base 1, is an car 67 that is domed in a direction toward the motor structure 3, the domed portion having a central opening 68 which provides a bearing for one side of the armature.

As best seen in FIG. 6, armature 4 is in the form of an elongated rectangle when viewed in side elevation and has a rectangular transverse cross section. Integral pivot pins 69 project at right angles from the centers of opposite ones of the long edges of the armature. As best seen in FIG. 2, the armature is disposed between electromagnet 36 and permanent magnets 47 and 48 and is of such length that a portion of the rectangular face of the armature extends across each of the pole faces 55 and 56. Pivot pin 69 which projects toward the base extends into opening 68 of ear 67, whereas pivot pin 69 which projects away from the base extends through an opening 70 in a bracket member 71 that is secured to the fixed magnetic structure 59 along the edge opposite the edge that is secured to bracket 5. Bracket 71 is preferably of nonmagnetic material and has an ear 72 projecting in the same direction as and parallel with ear 67. Bar 72 is domed downwardly concentric with opening 70 so that the space between the domed portions of ear 67 and car 72 is exactly the same as the distance between the long edges of the armature from which the pivot pins extend.

At each side of the pivot, the rectangular face of the armature is provided with a domed portion 73 and 74 that projects toward the polefaces 55, 56 and engages a pole face when the relay is in operation. The ends of the armature are angled slightly in a direction away from the pole faces so that only the domed portions engage a pole face.

. Fixed adjacent each end of that long edge of the armature which faces the base is a contact operating pusher in the form of a curved stiff wire, the contact operating pushers 75 and 76 projecting toward base 1 through the opening in the frame of bracket and having at their free ends pusher beads 77 and 78 of insulating material that engage respectively with the exposed portions of the free ends of movable contacts 34 and 35.

Due to the latching effect of the permanent magnet, the armature is always disposed in either a first position in which it contacts and is magnetically latched to pole face 55, or a second position in which it contacts and is magnetically latched to pole face 56. It is to be noted that face 50 of rectangular member 49 has a first side edge which is closely adjacent a rear surface of the armature at one side of the pivot when the armature is in its first position, and has a second side edge opposite the first which is closely adjacent a rear surface of the armature on the other side of the pivot when the armature is in its second position. Hence, in either position of the armature, a very minute air gap is-forme'd between the armature and an edge of rectangular member 49. However, the gap is much greater during the pivotal swing of the armature which is an important feature the purpose of which will subsequently be described.

Thus, in the relay of this invention, motor structure 3 is supported by bracket 5. The axis of core 37, as best seen in FIGS. 2 and 3, is disposed parallel with side 9 of the base and is offset from the center of the relay toward the side 9. Armature 4 is offset toward side 8 of the base from the center thereof, the pivotal axis of the armature, defined by pins 69 and hearings in brackets 5 and 71, being perpendicular to base 1 at a point offset toward side 8 of the base from the center of the base. By virtue of this arrangement, the height of the relay in a the base to hermetically seal the relay.

Turning now to the schematic drawing of FIG. 7 which shows the various electrical and magnetic circuits of the relay, the operation of the relay will be described.

Although there are several coil and operating arrangements that can be used to operate latching relays of this type, only the operation of the preferred embodiment which employs two coils to respectively latch and reset the armature will be described. To simplify the description of operation of the relay, the effect of the permanent magnet flux on the flux of the electromagnet will not be considered, since the effect is not significant.

In the position shown in FIG. 7, armature 4 engages pole face 56 and is magnetically latched in this position because of the effect ofpermanent magnet 47. The flux from permanent magnet 47 follows the path shown in dot-dash lines and flows from the north pole of magnet 47, through a portion of member 42, then through pole piece 52, across pole face 56 into armature 4, then across the air gap between the armature and rectangular member 49, and back to magnet 47 to complete the flux path. Since magnet 48 is disposed with its south pole adjacent the south pole of magnet 47, a similar flux path will be formed when the armature is pivoted to engage pole face 55. 5

To pivot the armature from the position of FIG. 7 to the position in which the armature engages pole-face 55, it is necessary that the magnetic attractive force between pole face 55 and the armature exceed the latching force of magnet 47. However, it is also necessary that the electromagnetic flux be of the proper polarity to assist the flux due to magnet 48. The flux due to magnet 48 follows a path similar to that of magnet 47, but in the opposite direction, the flux from magnet 48 flowing in a clockwise direction through end member 42, pole face 55, the air gap between pole face 55 and the armature (when the armature is in the FIG. 7 position), the armature itself, rectangular member 49, and back to magnet 48. Energizing coil 38 to create a flux that travels counterclockwise, as shown in FIG. 7 in solid lines, is effective to pivot the armature to a position in which it engages pole face 55. The flux of the electromagnet travels primarily through the pole pieces, armature, and core, and when coil 38 is energized the counterclockwise flux assists the flux of magnet 38 to increase the magnetic attraction between pole face 55 and the armature. As soon as the electromagnetic flux begins to move the armature toward pole face 55, the magnetic circuit due to magnet 47 opens and the armature switches instantaneously into engagement with pole face 55. As the armature begins to move, the air gap between rectangular member 49 and the armature increases, the increase in that air gap further reducing the effect of magnet 47 to maintain the armature in the FIG. 7 position, so that the armature quickly switches. To return the armature to the FIG. 7 position, coil 39 is energized as shown to create flux in a clockwise direction, (not shown) whereupon the flux assists magnet 47 and the armature again engages pole face 56.

Beads 77 and 78, carried at opposite ends of the armature, actuate contacts 34 and 35, respectively. When the armature is in one position with domed portion 73 engaging pole face 55, head 78 holds contact 35 in engagement with fixed contact 33, and movable contact 34 engages fixed contact 31 because of the spring properties of contact 34, bead 77 being spaced slightly from the movable contact (FIG. 5). When the armature is switched so that domed portion 74 engages pole face 56, bead 77 moves movable contact 34- into engagement with fixed contact 30, and simultaneously bead 78 moves away from movable contact 35 to allow the movable contact to return by its own resiliency into engagement with fixed contact 32. Hence, the movable contacts exert a force against the armature in a direction to oppose the latching magnet. This opposing force assists switching of the armature from one position to the other when the electromagnet is properly energized. Even though the contacts 30 and 33 are termed fixed contacts, these con tacts have natural resiliency, being formed of spring material having good electrical conducting properties, and being supported at one end only. Hence, these contacts are flexed somewhat when the movable contacts are brought into engagement with them. The resiliency of contacts 30 and 33 also tends to move the armature to oppose the latching magnet. These opposing forces of both the fixed and movable contacts combine to assist switching of the armature by the electromagnet.

Although a preferred embodiment of the relay of this invention has been described and shown in detail, it is to be understood that the scope of the invention is not limited thereto and that numerous changes and ramifications can be made without departing from the scope of the invention.

What is claimed is: 1. In a compact miniature electromagnetic relay, the combination of a header comprising a flat rectangular support member and a plurality of conductive pins extending therethrough; a motor structure; means mounting said motor structure on said support member in spaced relation thereto; and a contact assembly including fixed and movable contacts carried by said pins and disposed between said motor structure and said support member, said motor structure comprising an electromagnet having an elongated magnetic material core extending parallel to said support member and a coil surrounding said core, said core being parallel to two of the sides of said support member and offset from the center of said support member toward one of said sides,

a pair of straight flat magnetic end members coupled to the ends of said core and projecting laterally therefrom in aligned relation relative to said core, r

a substantially straight continuous elongated magnetic structure extending between said end members in spaced parallel relation to said electromagnet,

said core, said end members and said magnetic structure cooperating to define a generally rectangular flux path parallel to said support member, and

an elongated magnetic material armature disposed for pivotal movement about an axis perpendicular to said support member, said armature being disposed between said magnetic structune and said electromagnet within the bounds of said rectangular flux path, and

magnetic material pole pieces between said armature and said coil, said pole pieces being magnetically coupled to said end members and each providing a pole face directed away from the axis of said core;

said substantially straight elongated magnetic structure comprising a first straight permanent magnet having an end secured to one of said end members,

a second straight permanent magnet having an end secured to the other of said end members,

said permanent magnets extending toward each other and terminating at facing ends spaced from each other, and magnetic material means connecting the facing ends of said permanent magnets; one of said permanent magnets being effective to magnetically latch said armature to one of said pole faces when said armature is in a first position engaging said one of said pole faces and the other of said magnets being effective to latch said armature to the other of said pole faces when said armature is in a second position engaging the said other of said pole faces. 2. An electromagnetic relay in accordance with claim 1 in which said pole pieces are L-shaped, a first leg of each of said pole pieces defining said pole faces, and a second leg of said pole pieces being in abutting relation with said respective end members, the ends of said second legs of said pole pieces abutting said magnetic structure. 3. An electromagnetic relay in accordance with claim 2 in which said ends of said second legs of said pole pieces abut the respective permanent magnets of said magnetic structure, and said ends of said second legs of said pole pieces are recessed to engage the permanent magnets at areas less than the cross sectional area of a leg, whereby a decrease in the effective length of said permanent magnets as a result of the magnetic shunting effect of said second legs of said pole pieces is avoided. 4. In a compact, miniature, magnetically latching electromagnetic relay, the combination of a flat rectangular header a motor structure; means mounting said motor structure on said header in spaced relation thereto 7 a contact assembly comprised of stationary and movable contacts carried by said header and disposed between said motor structure and said header said motor structure comprising an electromagnet having an elongated core extending parallel to said support member and a coil surrounding said core, said core being parallel to two of the sides of said support member and offset from the center of said support member toward one of said sides, first and second magnetic members fixed to the opposite ends respectively of said core, said members extending transversely from said core and terminating at ends aligned with each other, a continuous magnetic structure fixed to and extending between the ends of said first and second magnetic members, first and second pole pieces magnetically coupled to the opposite ends of said core and extending toward each other parallel with and closely ad- .jacent said electromagnet, to present a pair of pole faces facing away from said electromagnet, an armature disposed between said magnetic structure and said pole pieces, and contact operating means carried by said armature; said magnetic structure including first and second permanent magnets said means mounting said motor structure on said header being in the form of a first non-magnetic bracket comprising a motor structure supporting portion fixed to at least said magnetic structure of said motor structure, and a plurality of legs on said supporting portion and fixed to said header;

a second non-magnetic bracket in engagement with and secured to said continuous magnetic structure means on said first and second brackets to mount said armature for pivotal movement to a first position in which one end of said armature engages one of said pole faces, and a second position in which the other end of said armature engages the other of said pole faces; said electromagnet providing means to move said armatune to said first and second positions; and said permanent magnets being effective to magnetically latch said armature in either of said positions. 5. An electromagnetic relay in accordance with claim 4 in which said motor supporting portion of said first bracket is in the form of a rectangular frame with an opening therein completely bounded by the frame, and said means carried by said armature to operate said contacts extends through said opening of said frame.

10 6. An electromagnetic relay in accordance with claim 4 in which the ends of said armature are each provided with domed projections which engage said pole faces.

References Cited by the Examiner UNITED STATES PATENTS 2,203,888 6/1940 Ashworth 317-172 2,846,542 8/1958 Stanley 200 93 3,109,903 11/1963 Lychyk 20087 3,138,677 6/1964 Adams 317 197 X FOREIGN PATENTS 108,412 8/1939 Australia.

BERNARD A. GILHEANY, Primary Examiner. JOSEPH J. BAKER, Assistant Examiner.

Claims (1)

1. IN A COMPACT MINIATURE ELECTROMAGNETIC RELAY, THE COMBINATION OF A HEADER COMPRISING A FLAT RECTANGULAR SUPPORT MEMBER AND A PLURALITY OF CONDUCTIVE PINS EXTENDING THERETHROUGH; A MOTOR STRUCTURE; MEANS MOUNTING SAID MOTOR STRUCTURE ON SAID SUPPORT MEMBER IN SPACED RELATION THERETO; AND A CONTACT ASSEMBLY INCLUDING FIXED AND MOVABLE CONTACTS CARRIED BY SAID PINS AND DISPOSED BETWEEN SAID MOTOR STRUCTURE AND SAID SUPPORT MEMBER, SAID MOTOR STRUCTURE COMPRISING AN ELECTROMAGNET HAVING AN ELONGATED MAGNETIC MATERIAL CORE EXTENDING PARALLEL TO SAID SUPPORT MEMBER AND A COIL SURROUNDING SAID CORE, SAID CORE BEING PARALLEL TO TWO OF THE SIDES OF SAID SUPPORT MEMBER AND OFFSET FROM THE CENTER OF SAID SUPPORT MEMBER TOWARD ONE OF SAID SIDES, A PAIR OF STRAIGHT FLAT MAGNETIC END MEMBERS COUPLED TO THE ENDS OF SAID CORE AND PROJECTING LATERALLY THEREFROM IN ALIGNED RELATION RELATIVE TO SAID CORE, A SUBSTANTIALLY STRAIGHT CONTINUOUS ELONGATED MAGNETIC STRUCTURE EXTENDING BETWEEN SAID END MEMBERS IN SPACED RELATION TO SAID ELECTROMAGNET, SAID CORE, SAID END MEMBERS AND SAID MAGNETIC STRUCTURE COOPERATING TO DEFINE A GENERALLY RECTANGULAR FLUX PATH PARALLEL TO SAID SUPPORT MEMBER, AND AN ELONGATED MAGNETIC MATERIAL ARMATURE DISPOSED FOR PIVOTAL MOVEMENT ABOUT AN AXIS PERPENDICULAR TO SAID SUPPORT MEMBER, SAID ARMATURE BEING DISPOSED BETWEEN SAID MAGNETIC STRUCTURE AND SAID ELECTROMAGNET WITHIN THE BOUNDS OF SAID RECTANGULAR FLUX PATH, AND MAGNETIC MATERIAL POLE PIECES BETWEEN SAID ARMATURE AND SAID COIL, SAID POLE PIECES BEING MAGNETICALLY COUPLED TO SAID END MEMBERS AND EACH PROVIDING A POLE FACE DIRECTED AWAY FROM THE AXIS OF SAID CORE; SAID SUBSTANTIALLY STRAIGHT ELONGATED MAGNETIC STRUCTURE COMPRISING A FIRST STRAIGHT PERMANENT MAGNET HAVING AN END SECURED TO ONE OF SAID END MEMBERS, A SECOND STRAIGHT PERMANENT MAGNET HAVING AN END SECURED TO THE OTHER OF SAID END MEMBERS, SAID PERMANENT MAGNETS EXTENDING TOWARD EACH OTHER AND TERMINATING AT FACING ENDS SPACED FROM EACH OTHER, AND MAGNETIC MATERIAL MEANS CONNECTING THE FACING ENDS OF SAID PERMANENT MAGNETS; ONE OF SAID PERMANENT MAGNETS BEING EFFECTIVE TO MAGNETICALLY LATCH SAID ARMATURE TO ONE OF SAID POLE FACES WHEN SAID ARMATURE IS IN A FIRST POSITION ENGAGING SAID ONE OF SAID POLE FACES AND THE OTHER OF SAID MAGNETS BEING EFFECTIVE TO LATCH SAID ARMATURE TO THE OTHER OF SAID POLE FACES WHEN SAID ARMATURE IS IN A SECOND POSITION ENGAGING THE SAID OTHER OF SAID POLE FACES.

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