US3486142A

US3486142A - Electromagnetic relays

Info

Publication number: US3486142A
Application number: US694231A
Authority: US
Inventors: Philip Vernon Little
Original assignee: Lucas Industries Ltd
Current assignee: ZF International UK Ltd
Priority date: 1967-01-16
Filing date: 1967-12-28
Publication date: 1969-12-23
Anticipated expiration: 1986-12-23
Also published as: DE1815613A1; GB1200321A; FR1597899A; DE1639295B2; FR1551497A; GB1239930A; US3524153A; DE1639295A1

Description

Dec. 23, 1969 P. v. LHTTLE ELECTROMAGNETIC RELAYS I Filed Dec. 28, 1967 Q \I/NV NTOR ATTQRNEYS United States Patent 3,486,142 ELECTROMAGNETIC RELAYS Philip Vernon Little, Burnley, England, assignor to Joseph Lucas (Industries) Limited, Birmingham, England Filed Dec. 28, 1967, Ser. No. 694,231 Claims priority, application Great Britain, Jan. 16, 1967, 2,186/67 Int. Cl. H01h 9/00 US. Cl. 335-203 2 Claims ABSTRACT OF THE DISCLOSURE An electromagnetic relay includes a casing, an electromagnet housed within the casing, and an armature which is urged away from the electromagnet by a leaf spring, and which is movable towards the electro magnet in response to energisation of the magnet. The armature carries a movable contact which is engageable with a fixed contact in response to energisation of the electromagnet. The leaf spring and the armature are interconnected by a deformable link, the length of which is adjustable to determine the operating voltage of the relay.

This invention relates to electromagnetic relays of the kind including a casing, an electromagnet housed within the casing, an armature urged away from the electromagnet and movable towards the electromagnet in response to energisation of the electromagnet, a movable contact carried by the armature, and a fixed contact engageable by the movable contact.

According to the invention in a relay of the kind specified, the armature is urged away from the electromagnet by a leaf spring, the leaf spring and the armature being interconnected by a deformable link which is adjusted to determine the operating voltage of the relay.

One example of the invention is illustrated in the accompanying drawing, which is a sectional view of an electromagnetic relay.

Refering to the drawing, the relay includes a moulded synthetic resin casing 11 of open box like construction, having a base 12. The electromagnet 13a of the relay is housed in the casing 11 and the coil 13 thereof is wound on a moulded former 14. Secured to the former 14 are two pairs of conductive blade terminals 15, 16 (one of each of which is seen in the drawing), the terminals 16 each including a contact adjacent the coil 13 while the terminals 15 are connected to the ends of the coil 13 respectively.

The core 17 of the electromagnet 13a extends axially through the coil 13 and is parallel to the base 12. Secured to one end of the core 17 is one limb of an L-shaped member 18, the other limb of which extends parallel with the core 17 and carries at its free end the armature -19 of the relay. The armature 19 extends at right angles to the core 17 and carries at its end remote from the member 18 a bifurcated conductive member 21 having integral therewith a pair of contacts 22 (only one of which is visible in the drawing). Also secured to the core 17 and extending for part of its length in contact with said one limb of the member 1 8 is a leaf spring 23 and extending between the free end of the spring 23 and the end of the armature remote from the member 21 is a ductile wire link 24. The link 24 is formed at its ends 'ice with hook portions which extend through holes in the spring 23 and armature 19 respectively.

During assembly of the relay the terminals 15, 16 are engaged with slots in the base 12, the terminals 15, 1'6 projecting from the base for connection to respective leads.

Each of the terminals, 15, 16 includes a resilient tab 25 which as the terminal is engaged with its respective slot, is flexed to allow the terminal to pass through the slot. The tags 25 are so arranged that when the former 14 engages the inner surface of the base 12, the tags 25 can flex outwardly to engage the outer surface of the base 12 and thereby prevent withdrawal of the assembly from the casing.

The operation of the relay is as follows:

When the coil 13 is energised, the armature 19 is drawn against the action of the spring 23 towards the core 17 and in so doing brings the contacts 22 into engagement with the contacts 20 so electrically interconnecting the terminals 16 through the member 21 and completing an electrical circuit through the terminals 16. When the coil is de-energised, the armature 19 is returned by the spring 23 so breaking the circuit through the terminals 16.

When the coil 13 is de-energised, the member 21 engages a rib 28 formed on the wall of the casing 11. However, in a modification, a second pair of contacts are provided adjacent the wall of the casing and in the deenergised condition of the relay, the member 21 completes a second electrical circuit through the second pair of contacts.

In order to set the pull-in and dropout voltages of the relay, it is merely necessary to kink the link 24, whilst the member 21 is engaged with the rib 28 or with the second pair of contacts thereby shortening the link and adjusting the tension exerted by the spring 23.

After assembly of the relay the open end of the casing 11 is closed by a resilient plate 26, which is snapped into an internal circumferential groove 27 in the casing 11.

It will be appreciated that an alternative method of setting the pull-in and drop-out voltages of the relay would be to form the link 24 with a kink prior to assembly of the relay, the link then being lengthened or shortened by deforming the kinked portion of the link as required.

Having thus described my invention what I claim as new and desire to secure by letters Patent is:

1. An electromagnetic relay comprising in combination a. casing, an electromagnet housed within the casing, an armature urged away from the electromagnet and movable towards the electromagnet response to energisation of the electromagnet, a movable contact carried by the armature, a fixed contact engageable by the movable contact, wherein the armature is urged away from the electromagnet by a leaf spring, the leaf spring and the armature being interconnected by a deformable link, said deformable link forming the sole means for adjusting the gap between the fixed and movable contacts to determine the operating voltage of the relay.

2. A relay as claimed in claim 1 wherein the armature and the fixed contact are carried by a former on which the coil of the electromagnet is wound, the former having secured thereto a plurality of terminal members which in use extend through slots in the casing, and the 3 terminal members having resilient parts which are flexed to allow the terminals to pass through said slots, the parts then flexing to a position wherein they engage the easing to prevent withdrawal of said former from the easing.

References Cited UNITED STATES PATENTS 4 Rinke '..-.J 335-487 Heyhal.

Valleau 335297 Wright.

Zerwic 335-297 BERNARD A. GILHEANY, Primary Examiner H. BROOME, Assistant Examiner