US2834850A - Relay - Google Patents

Description

y 13, 1958 L. E. EARLING 2,834,850

RELAY Filed Feb. 12, 1954 INVENTOR; 450mm 04m: 5mm;

. Whig/v70.

ATTOR/VEV United States Patent RELAY Leonard Eugene Eariing, Logansport, ImL, assignor to Essex Wire Corporation Application February 12, 1954, Serial No. 409,793

2 Ciaims. (Cl. 200-104) This invention relates to relays and in particular to A. C. telephone type relays.

The problems associated with this latter type relay arise in part due to the small and miniature size of such relays. Space, weight and balance of moving parts are critical limitations due to the size of the relay.

The object of this invention is to provide a small A. C. telephone type relay without loss of contact capacity.

A further object of the invention is to obtain higher contact pressures, and wider contact gap distances using the low amount of space available for lever action and in the same vein to permit the use of heavier contact springs to obtain higher overload capacity.

In addition, it is an object of this invention to improve the efiiciency of the relay and to improve its life expectancy.

Other objects of the invention will be apparent to those skilled in the art on consideration of the following description in conjunction with the attached drawings where- Fig. l is a front elevation of a relay.

Fig. 2 is a side elevation of a relay.

Fig. 3 is an enlarged side elevation of the actuator member partially in section.

This invention is most useful when used in conjunction with A. C. relays. It can be used to advantage in D. C. relays Where compactness is a factor. However, as aforesaid it is most useful in an A. C. relay where the A. C. coil characteristics would dictate conventionally larger armature structure.

For a general understanding of the invention, reference is made to the comparable force characteristics of an A. C. and a D. C. relay.

In the case of a D. C. coil, there is normally no difiiculty with respect to the holding-in of the armature. When the armature closes, the air gap is minimized and the eiiiciency of the magnetic circuit is increased thereby increasing the force tending to hold the armature closed over that which originally picked-up the armature. This is the basis for the expression that a D. C. relay will hold-in more than it will pick-up. In contrast, an A. C. relay is normally said to pick-up more than it will hold-in. The A. C. current successively rises, falls, and reverses. The peak current will pick-up a relay armature, but as the A. C. current passes through zero the magnetic force falls to such a low level that the armature drops out. The effect of this A. C. cycling is normally minimized by the use of a shading ring. The current induced in the shading ring is suflicient to supply a certain amount of magnetic energy or, pull, on the armature during the period the A. C. current is passing through zero. Another factor tending to decrease the hold-in force of the A. C. relay is the lessening of the current flow in the coil as the armature closes. The impedance changes rapidly as the armature is closing and the increased inductance permits less current to flow in the coil.

The combination of these two factors, i. e., the cycling current, and the current decrease as the armature closes 2,834,850 Patented May 13, 1958 causes the chattering of an A. C. relay. The armature closes on the peaks of current but does not hold-in While the energizing current is passing through zero, and, as compared to a comparable D. C. relay there is considerably less average force tending to hold-in the armature. Consequently, the armature of an A. C. relay exerts comparably less force against a biased bearing element such as a contact spring.

This invention provides an improved armature system to make the most possible use of the lesser armature force available.

In Fig. 2, there is shown a relay embodying the principles of this invention. A coil assembly 10 is securely mounted to the base leg 14B of the L-shaped frame 14. The coil assembly comprises a winding (not shown), winding spool 15, core 16 and shading ring 17. The leads 11 provide for the external electrical connection to the coil.

The armature 12 is attached to the L-shaped frame 14 by means of the retainer plate 18 and armature lugs 128. An armature projection 12A fits into a blanked out portion of the retainer plate 18. The lugs 12B are bent normal to the main body of the armature and edge grip the L-frame 14. Thus, the armature 12 is held in bearing engagement with the edge 19 of the L-frarne 14 and pivots about the edge 19 when attracted to the core 16. The magnetic circuit for the relay is thus traced from the core 16 to the armature 12 to the frame 14 to the leg 14B of the frame 14, thence back to the core 16.

The armature 12 is provided with an extension 12C extending toward the base of the relay. As the armature 12 is actuated by energization of the coil 10, the free end of this extension moves arcuately about the pivot edge 19. Element 20 serves as a limiting stop for the armature.

An actuator 21 is attached to the L-shaped member 14 at the point 14A for pivotal movement thereabout.

The free end 2113 of the actuator 21 overlaps the free end of the armature extension 12C sufliciently so that as the armature extension 12C moves in response to the magnetic force of the coil, a concurrent movement of the actuator 21 takes place arcuately to the pivot point 14A. The actuator 21 is provided at the free end 21B with a groove 21A for mating engagement with the free end of armature extension 12C. When the armature extension is seated in the actuator groove there is little possibility for lateral disengagement of the armature extension and the actuator.

The actuator is further provided with a projection 21C in bearing contact with contact spring 23. A projection 28 attached to the contact spring 26 is also in bearing contact with contact spring 23 and is disposed oppositely to the projection 21C. Projection 28 by-passes contact springs 24 and 25. Contact springs 23 and 26 are biased downwardly as viewed in the drawing thus forcing the actuator 21 to hold the armature 12 in a normally open position.

When the coil 10 is energized, armature 12 is attracted to the core 16 of the relay. The armature pivots on the edge 19 of the frame 14 thus causing the armature extension 12C to move away from the stop 20. This motion forces the actuator 21 to pivot on its hinge pin at 14A. The pivoting of actuator 21 causes an upward sliding motion at its point of contact with contact spring 23. The upward movement of contact spring 23 results in a contacting with contact spring 24. Similarly, the linkage with projection 28 results in contact spring 26 contacting the contact spring 27.

The actuator may be made from any suitable material. A preferred material is nylon. This material has a characteristicaily low coefiicient of friction minimizing any endency of the actuator and armature extension to bind.

The ends of the contact springs, remote from the contact bearing ends are adapted in any desired manner for joining to the electrical circuits used in conjunction with the relay. The individual contact springs are supported in the pile-up assembly 29 and suitably insulated from each other with suitable insulating material 30 in a wellknown manner. It is to be noted that the exact structure shown in Fig. 2 is duplicated on the opposite side of the relay. The dual assembly is readily understood by reference to Fig. 1 wherein is shown the dual pileup assembly and dual actuator.

By use of this construction it is possible to utilize the low average hold-in force of the A. C. relay to operate multiple sets of contacts at higher contact pressure, with wider contact gaps and thicker contact springs than has been heretofore possible with conventional armature action.

Having thus described my invention, I claim:

1. A relay including an energizable coil, a support frame for said coil, an armature pivotally mounted to said frame and adapted to be attracted by the energization of said coil, and further characterized by an armature extension, an actuator in biased Overlapping engagement with the free end of said armature extension and pivotally hinged at the end remote from said armature extension, said actuator being furthercharacterized by a groove in the free end thereof for mating engagement with said extension to avoid lateral disengagement of the actuator and extension with the result that a concurrent displacement of the actuator results from armature action.

2. An electromagnetically operated switch comprising: a substantially L-shaped magnetic frame of a first leg and a second leg extending at substantially a right angle from one end of the first leg, a magnetic core rigidly joined at its first end with the frame first leg to extend ond leg, an energizing coil surrounding said core, a magnetic armature pivotally mounted on the end of the frame second leg opposite the frame first leg and overlying the second end of the core, an armature extension projecting toward the frame first leg in generally parallel spaced relation with one side of the frame, an assembly of contact springs insulatedly mounted on the frame second leg and from each other in a spring pile-up, said contact springs including at least a free spring and an actuator spring having free end portions provided with contacts, the free contact end of each spring extending in approximately parallel spaced relation with said frame second leg toward said frame first leg, an actuator of insulating material disposed along the same side of said frame that said armature extension is disposed, said actuator having a first end pivotably mounted adjacent the junction of said frame legs and having a second end overlying the free end of said armature extension, said actuator second end having a groove aligned with the free end of said armature extension into which groove the free end of said armature extension projects to prevent dislodgment of the armature extension from the actuator, and an actuator projection intermediate said actuator first and second ends having a bearing edge engaging said actuator spring for movement relative to said free spring upon movement of the armature.

References Cited in the file of this patent UNITED STATES PATENTS 749,814 Dawns Jan. 19, 1904 1,681,473 Erickson Aug. 21, 1928 2,538,819 Bellamy Jan. 23, 1951 2,588,534 Jargensen Mar. 11, 1952

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