US3792388A

US3792388A - Electrical relay

Info

Publication number: US3792388A
Application number: US00355815A
Authority: US
Inventors: O Fleming
Original assignee: Teledyne Inc
Current assignee: Teledyne Inc
Priority date: 1973-04-30
Filing date: 1973-04-30
Publication date: 1974-02-12
Anticipated expiration: 1991-02-12
Also published as: DE2413386B2; JPS5013867A; DE2413386A1

Abstract

An electrical relay having an armature pivotally mounted for rotational movement about an axis, and a movable contact assembly carried by the armature. Electrical continuity between the movable contact assembly and selected stationary terminals of a header assembly is achieved through compression loaded contacts at the rotational axis of the armature, thereby avoiding problems experienced with the conventional flexible wire connectors of the prior art.

Description

United States Patent [191' Fleming 1 1 Feb. 12, 1974 15 ELECTRICAL RELAY 3,444,491 I 5/l969 Whitaker 3.15/203 3, 18,589 61970 K M 335 135 [75] Inventor: Ora Ray Fleming, Pico Rivera, 5 06 er I Cahf' Primary Examiner-Haro1d Broome [73] Assignee: Teledyne, Inc., Los Angeles, Calif. Attorney, Agent, or Firm-Ronald W. Reagin 22 Filed: Apr. 30, 1973 r [57] ABSTRACT [21 1 App! 355315 An electrical relay having an armature pivotally mounted for rotational movement about an axis, and a [52] US. Cl 335/135, 335/203, 335/277 movable contact assembly carried by the armature. [5 1] Int. Cl. HOlh 50/60 Electrical continuity between the movable contact as- [58] Field of Search 335/135, 128, 129, 203, 196, sembly and selected stationary terminals of a header 335/276, 277, 133 assembly is achieved through compression loaded contacts at the rotational axis of the armature, thereby [56] References Cited avoiding problems experienced with the conventional UNITED STATES PATENTS flexible wire connectors of the prior art.

2,744,216 5/1956 Obszarny 335/277 6 Claims, 3 Drawing Figures PATENTED 2 3.792.388

saw 1 ur 2 PATENTED FEB I 21974 SHEET 2 BF 2 ELECTRICAL RELAY BACKGROUND OF THE INVENTION In a common type of electromagnetic relay, a movable contact is transferred from a normally open position to a closed position by means of an armature which is actuated by a coil. Electrical continuity from the moving contact to a stationary terminal is conventionally provided by a flexible lead wire soft soldered between them. The lead wire must be of a size adequate to carry the current load for which the device is in tended and yet it must be as flexible as possible to avoid mechanical bending moments and side loading on the armature. Such extraneous and, very likely, erratic forces tend to make the relay unreliable in operation over a large number of cycles. I

In order to increase the flexibility of the lead wire from the movable'contact, a multistran d conductor is almost always used, and an extra length or loop is provided to further reduce the bending force of the wire on the armature. Care must also be taken to route the wire so that the desired flexibility is obtained in most favorable spatial orientation. In miniature relays, it is not only difficult to maintain the optimum routing but the extra length provided to obtain flexibility occupies a considerable amount of the very limited space available.

The conventional lead wire must be soldered at each end to create a reliable bond with the moving contact and the stationary terminal. Unfortunately, the multistrand conductor, adopted for its flexibility, tends to act as a wick for the molten solder, which runs up the wire and, upon cooling, causes a marked stiffening in the region adjacent the soldered connection. This, in turn, results in higher bending forces being required to flex the lead, and increase the mechanical load on the magnetic circuit. Inrelays designed for long useful lives, the lead wire from the moving contact to the stationary terminal must flex millions of times. This tends to cause work hardening of the flexible portion of the conductors and may eventually lead to breakage and failure of the device.

SUMMARY OF THE INVENTION The invention completely eliminates the abovedescribed and other problems associated with the use of flexible lead-wires to connect the movable contacts of electrical relays to their respective stationary terminals.

In accordance with the principles of the invention, an electrical relay comprises an armature pivotally mounted for rotational movement about an axis, between 21 first and a second position; an electromagnetic coil for actuating the armature; and a'moving contact assembly affixed to the armature. Electrical continuity from the moving contact to a stationary terminal is provided by a movable first compression contact member affixed to the armature at its axis of rotation, which member bears against a stationary second compression contact member affixed to the stationary terminal. Because the compression contact is at the pivot point of the armature, it is characterized by very low friction and a very small rotary movement which tends to produce a self-wiping or cleaning action, resulting in a lowresistance electrical junction. The pivotal placement of the contact permits high contact pressures to be employed to minimize contact resistance with very little increase in the rotational force required to actuate the armature, so that relatively high current devices may employ the invention to advantage.

As the compression contact is located at the pivot point of the armature, so that only a slight movement of the opposing surfaces occursat each operating cycle, the device is capable of operating for an extended number of cycles which may be in excess of several million. The elimination of the conventional lead wires also permits the relay to be designed in a smaller package with a consequent saving of space in the equipment where it is ultimately used.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A and 1B are front and side views, respec- DESCRIPTION OF THE PREFERRED EMBODIMENT The drawing depicts an electrical relay comprising a header assembly 10 having a base portion 11 of an insulative material with a plurality of

conductive terminal pins

12, 13, 14, 15 and 16 extending therethrough. A magnetic actuation assembly 17 includes a coil 18 and an armature 19 adapted to actuate a movable contact assembly 21. Coil 18, which is rigidly mounted on base 11, is electrically connected to terminal pin 13 and to another terminal pin not visible in the drawing, and may be energized by applying an appropriate voltage between the terminals. Armature 19 is pivotally mounted for. rotational movement about an axis defined in the illustrative embodiment by armature edge 22 which bears against a lower surface of the coilsupporting frame 23. Armature 19 is rotatable between a first or open position in which its free end is spaced from the end of coil 18, and a second or closed position in which its free end is adjacent'the end of coil 18. When coil 18 is energized, armature 19 rotates from the first position to the second, and when coil 18 is de-energized, a spring 24 returns the armature 19 to the first position.

Movable contact assembly 21 comprises a contact button 26 at the free end of the resilient arm 27 which is affixed at its other end to armature 19 near its rotational axis 22. Contact button 26 is positioned, in the illustrative embodiment, between spaced

stationary terminal contacts

28 and 29 formed by the bent upper portions of

terminal pins

15 and 16 respectively. The spacing between the

stationary terminal contacts

28 and 29 is so related to the effective length of resilient arm 27 from the axis 22 of armature 19 that when armature 19 is in its first or open position button 26 is resiliently urged against terminal contact 29, and when armature 19 is in its second or closed" position button 26 is resiliently urged against terminal contact 28.

Arm 27 is affixed to armature 19 by means of a slotted insulative clip 31 which is attached to a projection 32 at the lower end of the armature. In the illustrative embodiment a flat portion of arm 27 fits snugly into the slot of clip 31 and is firmly held in place. Arm 27 is conductive and is electrically continuous with contact button 26, and is insulated from armature 19 by clip 31. A conductive tab 33 of arm 27 extends upwardly to intersect the geometrical extension of axis 22, providing a movable first compression contact surface substantially normal to axis 22. In the preferred embodiment, the movable compression contact surface is provided by a convex contact button 34 affixed to tab 33. A stationary second compression contact 36 is affixed to base assembly and extends upwardly to intersect the geometrical extension of axis 22, and is preferably normal thereto. The upward extension of stationary contact 36 is resilient and is positioned to bear resiliently against contact button 33 at the axis 22, thereby establishing a movable compression contact characterized by low friction and low electrical resistance. Stationary contacts 36 are electrically connected to terminal pins l2, 14 so that'electrical continuity is provided from movable contact buttons 26 at the ends of arms 27 through

terminal pins

12, 14. Thus, a double pole, double throw switch is provided by the illustrative relay embodying the invention.

Because the movable compression contact formed by

contacts

33 and 36 is located on the rotational axis of armature 19 and has a small area, there is very little friction to load the armature. The relative movement of compression contacts provides a wiping action to insure a low resistance junction. As the compression force of the contacts is exerted along the armature axis, no bending moments effect the armature itself. There are no flexible wires to be soldered and routed through the relay, or to be flexed when the relay is operated. Thus, numerous difficulties experienced by the prior art are avoided.

Although the invention is illustrated and described herein with reference to a specific embodiment, many variations and modifications are possible'and may be .made by those skilled in this art, without departing from its scope and spirit.

What is claimed is:

1. In an electrical relay including an electrical header assembly having a base portion, a magnetic actuation assembly including an armature pivotally mounted for rotation about an axis, and a movable contact assembly affixed to the armature for actuation thereby;

the improvement comprising a movable first compression contact member affixed to the armature with a contact surface at the axis of rotation thereof and a stationary second compression contact member affixed to the base portion of the header assembly with a contact surface at the rotational axis of the armature adjacent the contact surface of the first compression contact member, the first and second compression contact members being a compression contact on the rotational axis of the'armature, the movable first compression contact member being electrically connected to the movable contact assembly whereby electrical contact is established between the-stationary compression contact member and the movable contact assembly.

2. The improvement of claim 1 wherein the movable first compression contact surface and the stationary' second compression contact surface are substantially normal to the rotational axis of the armature at the region of contact.

3. The improvement of claim 1 wherein one of the compression contact surfaces is convex and the other compression contact surface is planar.

4. An electrical relay comprising an electrical header assembly, a magnetic actuation assembly and a movable contact assembly;

the electrical header assembly comprising an insulative support member having a plurality of contact pins extending therethrough, a stationary terminal contact connected to one of the contact pins, and.

' a stationary compression contactconnected to another of the pins;

the magnetic actuation assembly comprising a solenoid having a pair of electrical lead wires each of which is connected to a separate contact pin of the header assembly, and an armature pivotally mounted for rotational movement about an'axis, the armature being rotatable between a first position in which a free end is adjacent the solenoid when the solenoid is energized and a second position in which the free end is spaced from the solenoid when the solenoid is de-energized;

the movable contact assembly comprising a movable contact affixed to the armature and adapted in one position of the armature to engage the stationary terminal contact of the header assembly and in the other position of armature to be spaced from the terminal contact, and a compression contact electrically continuous with the movable contact positioned on the rotational axis of the armature and engaging the stationary compression contact of the header assembly in electrical compression contact on the axis, whereby electrical continuity is provided from the movable contact of a pin of the header.

5. An electrical relay as claimed in claim 4 wherein the stationary compression contact comprises a resilient member having a contact surface substantially normal to the rotational axis of the armature at its intersection therewith, the resilient member being adapted to urge the contact surface along the rotational axis of the armature in compression contact against the compression contact of the movable contact assembly.

6. An electrical relay as claimed in claim 5 wherein one of the compression contact surfaces is convex and the other is substantially planar.

Claims

1. In an electrical relay including an electrical header assembly having a base portion, a magnetic actuation assembly including an armature pivotally mounted for rotation about an axis, and a movable contact assembly affixed to the armature for actuation thereby; the improvement comprising a movable first compression contact member affixed to the armature with a contact surface at the axis of rotation thereof and a stationary second compression contact member affixed to the base portion of the header assembly with a contact surface at the rotational axis of the armature adjacent the contact surface of the first compression contact member, the first and second compression contact members being a compression contact on the rotational axis of the armature, the movable first compression contact member being electrically connected to the movable contact assembly whereby electrical contact is established between the stationary compression contact member and the movable contact assembly.

2. The improvement of claim 1 wherein the movable first compression contact surface and the stationary second compression contact surface are substantially normal to the rotational axis of the armature at the region of contact.

4. An electrical relay comprising an electrical header assembly, a magnetic actuation assembly and a movable contact assembly; the electrical header assembly comprising an insulative support member having a plurality of contact pins extending therethrough, a stationary terminal contact connected to one of the contact pins, and a stationary compression contact connected to another of the pins; the magnetic actuation assembly comprising a solenoid having a pair of electrical lead wires each of which is connected to a separate contact pin of the header assembly, and an armature pivotally mounted for rotational movement about an axis, the armature being rotatable between a first position in which a free end is adjacent the solenoid when the solenoid is energized and a second position in which the free end is spaced from the solenoid when the solenoid is de-energized; the movable contact assembly comprising a movable contact affixed to the armature and adapted in one position of the armature to engage the stationary terminal contact of the header assembly and in the other position of armature to be spaced from the terminal contact, and a compression contact electrically continuous with the movable contact positioned on the rotational axiS of the armature and engaging the stationary compression contact of the header assembly in electrical compression contact on the axis, whereby electrical continuity is provided from the movable contact of a pin of the header.