US2587557A - Relay - Google Patents

Description

Feb. 26, 1952 T. R. WELCH 2,587,557

RELAY Filed Feb. 16, 1946 INVENTOR. THOMAS ROSS WELCH ATTO RN EY.

Patented F eb. 26, 1952 UNITED STATES RATENT OFFICE RELAY Thomas R. Welch, Los Angeles, Calif. Application February 16, 1946, Serial No. 648,128

l-Claims. 1

This invention relates to electric relays, and more particularly to relays for controlling a plurality of electric circuits.

It is an object of the invention to provide a device of this character wherein a very small force is required to operate same. This object is effected by subjecting the respective sides of the armature of the device to substantially balanced forces acting in opposition to each other. The

means for actuating the armature may be electro-magnetic in character and said means, because of the normally balanced condition of the armature, need exert a force thereon of a value only slightly greater than the force necessary to overcome the inertia and the relatively small pivotal friction of the armature and switches. A further advantage of this arrangement is that the switches will be held in whatever position to which they are moved.

It is another object of the invention to provide 1? a device of this character wherein the switches are so constructed and arranged as to provide the opposing forces on the respective sides of the armature.

Another feature of the invention is to provide a device of this character wherein the switches have a snap latching action, which action is provided by spring means on the pivots of the contact members thereof, with a compressively stressed movable contact member fioatingly and resiliently mounted thereon for effecting said snap action when moved past the neutral position.

Prior art relays, of which I am aware, are generally complex devices having a large number of parts which often require fine adjustments that are difiicult to make and difiicult to maintain.

It is a further object of the present invention to provide a relay of simple construction and having relatively few parts.

It is another object of the invention to provide a device of this character that is sturdy, compact, and reliable in operation.

Other objects and advantages of the invention will appear from the following part of the specification.

In the drawings, which are for illustrative purposes only:

Figure 1 is a side view of a relay embodying the present invention;

Figure 2 is a sectional view thereof taken on .line 2-2 of Figure 1;

Figure 3 is a horizontal sectional view taken on line 3-3 of Figure 1;

Figure 4 is an enlarged fragmentary view of the switch actuator assembly, and,

Figure 5 is a diagram illustrating the forces to which the armature is subjected.

As shown in the drawing, the device generally comprises a supporting frame, a movably mounted armature, means to maintain the armature in balance, switch means to be actuated by the armature, and means for actuating said armature.

Referring to the drawings, the relay is shown as comprising a supporting frame, indicated generally at 4, which may be stamped from sheet metal. The frame 4 is generally U-shaped in form and in the inverted position, said frame having a substantially horizontal upper member 5 and depending leg members '6. The lower ends of the legs have inturned ears 1 whereby the frame 3 is mounted on a supporting base 8 by means of screws 9. The base may be mounted to a support by means of legs I0 which are downwardly ofiset, as shown in the drawing, from the base 3. The armature, indicated generally at H, may be of soft iron or other suitable material, and is pivoted at 12 adjacent its upper end to the member 5 of the frame, and is adapted to normall depend therefrom substantially midway between the members 6.

Switches Ba and [3b are mounted on the base 8 on each side of the armature adjacent the free end thereof, and said switches are secured to the base 8, in spaced relationship to each other'by screws l4. Each switch includes a plunger or actuator member l5, slidable in an opening provided therefor in a member l6 of the switch box. Each plunger is provided with an annular flange ll, slidable in a counter bore I8 in the member l6, and said plunger carries an axial stem l9 which extends outwardly, as shown in the drawing. The stem has a reduced diameter portion lBa, slidable in an opening in a member 2!] of the switch box. The plungers l5 bear on the armature, adjacent its free end, and are urged against the armature by yielding means which, as shown, comprises a spring 2| disposed on the reduced diameter portion Mia and reacting between the portion 20 and a shoulder 23 of the stem Hi.

The switch contact mechanism is shown as comprising a movable contact plate 24 slidably disposed on each of the stems [9. These plates extend laterally of the stems l3 and carry contacts 24a adjacent their free ends, said contacts 24a being located between fixed contacts 25 and 26, to which respective electric wires 2! and 28 are attached. The contacts 24a of each switch are adapted to abut against either the contacts 25 or the contacts 26 for completing an electric circuit. Armature balancing means is shown as comprising the springs 2!, said springs being so calibrated as to exert substantially equal force on opposite sides of the armature, and since the radius of operation of the armature from point of fulcrum is so small as to be negligible, all the forces in one direction are either all positive or all negative. Since these opposing forces are equal, their resultant is zero, and the armature remains in any position to which it is moved. In case the forces are not exactly equal in commercial production, they will be so nearly equal that any small resultant force will not be enough to change the armature position.

Each switch is of the snap-action type. As shown, the means for effecting such action comprises a bow spring 29 having a medial opening for reception of the stem I9 and outwardly turned end portions 29a which provide V-shaped notches 3! adjacent the ends of said bow spring. A member 36 is secured to each end of the plate 2 1 and extends inwardly to a position whereat the free ends of said members 25 are received in V- shaped notches 3| of the bow spring 29. The members 3e are of sufiicient length so that the bow spring 29 is compressed upon actuation of the switch plunger l5, past the neutral position which is the plane of the plate 24. Thus when the free ends of the members 30 are moved past the plane of the plate 24, there is a snap action which will eifect actuation of the said plate 24 and move the contacts 24a from a position engaging one set of the contacts 25 to a position engaging the contacts 26.

Means for moving the armature laterally comprises, in the present embodiment, electromagnets 241), there being one magnet mounted adjacent each side of the armature intermediate the adjacent switch box and the top member 5 of the frame. These magnets comprise the usual coils, having binding posts 25' for attachment of the circuit wires, and cores 26' extending oppositely of each other with their adjacent ends spaced apart to operatively receive the armature therebetween.

When one of the magnets, for example, the right-hand magnet, is energized, the armature is pulled to the right into the position shown in Figure 1. At the same time the contact member I5 on the right-hand side of the armature is moved to the right, as shown in the drawing, and the left-hand plunger l5 follows up the movement of the armature.

Referring now to Figure 5, the lateral force necessary to move the armature and actuate the switch units is shown. This force is only slightly greater than the sum of the inertia resistance of the armature plus the pivotal friction'at the point of suspension, In Figure 5, a represents the reaction of the switch unit l3a, and b represents the reaction of the switch unit l3b; i represents the inertia resistance of the armature and other moving parts; represents the pivotal friction of the armature, and 0 represents the force necessary to unbalance the substantially balanced condition of the armature and move same to cause actuation of one of the switch units. As I) is equal to a, it has been found that if the switches 13a and [3b exert a force of approximately 400' grams, a force of approximately 100 grams will unbalance the mechanism and keep the switch l3a actuated. Thus the total power of the electromagnet assembly need be only approximately one-half the force exerted by each switch, or one-fourth the force exerted by the two switches together, plus the inertia of the mechanism and the frictional resistances.

More particularly, let it be assumed that with the parts of the mechanism as shown in Fig. 3, wherein the right-hand spring 2| is compressed, said spring exerts a force of approximately 300 grams. The other, or left-hand spring 2i, is expanded and exerts less force in opposition to the right-hand spring 2|, say approximately 200 grams, because of its expanded condition, it being understood of course that said springs 2| are under load at all times. Further, let it be assumed that each of the bow springs 29 exert a force of approximately grams against movement of the switches whenever said springs are out of their neutral position. Thus there is a force of approximately 300 grams exerted by the right-hand spring 2i which is opposed by the combined force of approximately 200 grams of the left-hand spring 2| and the force of approximately 100 grams of each of thesprings 29, making a total force of approximately 400 grams opposing a force of approximately 300 grams of the right-hand spring 2|. Hence, a force of approximately 100 grams or very little more, will sufice to move the switches from the position shown in Fig. 3 to their opposite position whereat the contacts 24a engage the contact points 26.

Now the situation is reversed and the lefthand spring 2| is exerting a force of approximately 300 grams, which force is opposed by a spring force of approximately 400 grams which is the total force exerted by the right-hand spring 2! and the bow springs 29.

It will be obvious from the foregoing that the opposed forces are nearly balanced and that a relatively small force only is required to operate the switches. Depending upon the sensitiveness desired in the switch, the balancing of the switches may be very much closer than the example set forth above, the values of said example being used merely to clearly bring out the action of the device. Further, it is to be understood that the invention will also work satisfactorily with other types of snap-action, over-action or micro switches.

It is also to be pointed out that the present device belongs to that general type of arrangement known as a latching relay.

I claim;

1. In an electric relay, the combination of: a pivoted armature; a switch adjacent each side of said armature, said switches each including a movable member actuated by movements of said armature, said switches also including yielding means for simultaneously subjecting each side of the armature to a yielding force of substantially equal value at all positions throughout the range of movement of said armature; and means for actuating said armature for effecting actuation of the switches.

2. In an electric relay, the combination of: a frame; an armature pivoted thereto; armatureattracting means mounted on the frame on each side of the armature; and switch means mounted on the frame on each side of the armature beyond said armature-attracting means and each having a spring loaded contact operating member engaging at all times the adjacent side of the armature and simultaneously exerting thereon a force equal and opposite to the other so as to maintain the armature in a substantially balanced condition in all positions of said armature.

3. In a relay, the combination of: a frame; an armature pivoted at one end to one side of the frame; electromagnets opposingly arranged on the adjacent sides of the frame with a transverse gap therebetween for the armature to extend through; and switches mounted adjacent to opposite side of the frame to the first, laterally of the other end of the armature, said switches including actuatable contacts arranged to respectively thrust and resist said armature simultaneously with substantially equal and opposed forces in all positions of said armature.

4. In a relay, the combination of: a frame; an armature pivoted at one end to one side of the frame; electromagnets opposingly arranged on the adjacent sides of the frame with a transverse gap therebetween for the armature to extend through; and switches mounted on the opposite side of the frame to the first, laterally of the other end of the armature, the switches having actuatable contacts arranged to respectively thrust and resist said armature simultaneously with substantially equal and opposed forces in all positions of said armature, each contact member carrying a floating, resilient switch member organized with a plurality of circuits and adapted to alternately close and open same when its contact member is alternately actuated.

5. In a relay, the combination of: a frame;

an armature pivoted at one end to one side of the frame; electromagnets opposingly arranged on the adjacent sides of the frame with a transverse gap therebetween for the armature to extend through; and switches mounted on the op posite side of the frame to the first, laterally of the other end of the armature, the switches having actuatable contacts arranged to respectively thrust and resist said armature simultaneously with substantially equal and opposed forces in all positions of said armature, each contact member carrying a movable, resilient switch member organized with a plurality of circuits and adapted to alternately close and open same when its contact member is alternately actuated, each resilient member having a compressively stressed position passing of which in either direction tends to actuate said switches.

6. In an electric relay: a movable armature;

a switch adjacent each side of said armature each switch having an operating member engaging the armature at all times and adapted to be actuated upon movement thereof; yielding means simultaneously urging the armature in opposite directions with substantially equal force at all the positions of said armature throughout its range of movement; movable resilient means adapted to exert force against said armature and having a position beyond which, in either irection therefrom, switch moving force is exerted in the same direction as one of said yielding means and against the other of said yielding means; and electrical means for actuating said armature.

7. In a device of the class described: an armature supported for operative movement; oppositely arranged electromagnets disposed adjacent to said armature for moving said armature in respective directions upon energization of the respective electromagnets; oppositely arranged switches including actuatable contacts operatively connected with said armature and biased to respectively thrust and resist movement of said armature simultaneously with substantially equal and opposed forces in all positions of said armature.

8. In an electric relay: a pair of switches having operator members spaced apart from each other; an armature operably disposed between said members and adapted to operate same, said operators engaging the armature in all of its positions; yielding means biasing said switch operator members against said armature with substantially equal and opposite forces in all positions of said armature and snap action means for each of said switches tending to cause snap action of the device when the same is actuated.

9. In an electric relay: a pair of switches each having a contact operator member; an operating lever spacing said operator members apart, said operator members engaging said lever in all positions of the latter; and spring means biasing said contact operator members against said operating lever with substantially equal and op posite forces in all positions of said operating lever.

THOMAS R. WELCH.

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

UNITED STATES PATENTS Number Name Date 274,112 DInfreville Mar. 20, 1883 1,162,071 Jordan Nov. 30, 1915 1,172,294 Krum Feb. 22, 1916 1,250,152 Eisenmann Dec. 18, 1917 1,497,300 Minton June 10, 1924 1,971,199 Owens Aug. 21, 1934 1,940,032 Ulrich Dec. 19, 1933 2,313,919 Burt Mar. 16, 1943 2,337,251 Knudsen Dec. 21, 1943 2,357,878 Crew Sept. 12, 1944 2,360,128 Hausler Oct. 10, 19,44

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