US3486141A - Electromagnetic relays - Google Patents

Description

P. V. LITTLE ELECTROMAGNETIC RELAYS Dec. 23, .1969

Filed Nov. 2'7, 1967 ENTR uak M4 ATTORNEYS v United States Patent 3,486,141 ELECTROMAGNETIC RELAY S Philip Vernon Little, Burnley, England, assignor to Joseph Lucas (Industries) Limited, Birmingham, England, a British compan Filed Nov 27, 1967, Ser. No. 685,803 Claims priority, application Great Britain, Dec. 12, 1966, 55,489/ 66 Int. Cl. H01h 3/00 US. Cl. 335-187 3 Claims ABSTRACT OF THE DISCLOSURE In an electromagnetic relay there is provided a casing including a base, an electromagnet housed within the casing and including a coil wound on a former, an armature carrying a movable contact of the relay, and a fixed contact engageable by the movable contact. The armature and the fixed contact are carried by the former on which the coil is wound and the former has secured thereto a plurality of terminal members which in use extend through slots in the base of the casing, the terminal members having resilient parts which are flexed to allow the terminal members to pass through the slots in the base of the casing and the parts then flexing to a position wherein they engage the base to prevent withdrawal of the former and its associated parts from the casing.

This invention relates to electromagnetic relays of the kind comprising a casing including a base, an electromagnet housed within the casing :and including a coil wound on a former, an armature carrying the movable contact of the relay, and a fixed contact engageable by the movable contact.

According to the invention in a relay of the kind specified the armature and the fixed contact are carried by the former on which the coil is wound and the former has secured thereto a plurality of terminal members which in use extend through slots in the base of the casing, the terminal members having resilient parts which are flexed to allow the terminals to pass through the slots the parts then flexing to a position wherein they engage the base to prevent withdrawal of the former from the casing.

One example of the invention is illustrated in the accompanying drawings wherein;

FIGURE 1 is a sectional view of an electromagnetic relay,

FIGURE 2 is a sectional view on the line 22 in FIGURE 1 with the armature and its associated return spring omitted for clarity, and

FIGURE 3 is a view in the direction of arrow A in FIGURE 1.

Referring to the drawings, the relay includes a moulded synthetic resin casing 11 of open box like construction, having a base 12. The coil 13 of the relay is housed in the casing 11 and is 'wound on a moulded former 14. Secured to the former 14 are two pairs of conductive blade terminals 15, 16 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 relay 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. The member 18 includes a part 23 which extends substantially parallel with the armature 19, the part 23 and the end of the armature 19 remote from the member 21 being interconnected by a spring 24.

In order to assemble the relay the terminals 15, 16 are engaged with slots in the base 12, the terminals 15, 16 projecting externally from the base for connection to respective leads.

Each of the terminals 15, 16 includes a resilient tag 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 11.

The opreation of the relay is as follows:

When the coil 13 is energised the armature 19 is drawn against the action of the spring 24 towards the core 17 and in so doing moves the contacts 22 into engagement with the contacts 20 so electrically interconnecting the terminals 16 through the member 21, and completing a circuit through the terminals 16. When the coil 13 is deenergised the armature 19 is returned by the spring 24 so breaking the circuit through the terminals 16.

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

After assembly 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.

In order to mount the relay in position on, for example a metal plate 29 constituting part of a road vehicle, the base 12 has a larger cross section than the remainder of the casing 11 and is formed with an external circumferential groove 28. The casing can then be inserted into a corresponding hole in the plate 29 and can be snapped into engagement with the plate, the periphery of the hole engaging the groove 28 in the base 12. Alternatively the base could be formed with a pair of outwardly directed lugs with which screws can be engaged to mount the relay in a more conventional manner.

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

1. An electromagnetic relay comprising a casing including a base, an electromagnet housed within the casing and including a coil wound on a former, an armature carrying the movable contact of the relay, and a fixed contact engageable by the movable contact, said armature and the fixed contact being carried by the former on which the coil is wound and the former having secured thereto a plurality of terminal members which in use extend through slots in the base of the casing, the terminal members having resilient parts which are flexed to allow the terminals to pass through the slots, the parts then flexing to a position wherein they engage the base to prevent withdrawal of the former from the casing.

2. A relay as claimed in claim 1 wherein the former is moulded in synthetic resin.

3. A relay as claimed in claim 1 wherein the casing is adapted to be mounted as a snap fit in an aperture in a panel.

References Cited UNITED STATES PATENTS 4 'Heyhal 20 0-166 Neurnann 335-187 Valleau 335-297 Wright 200-166 Zerwic 335-297 BERNARD A. GILHEANY, Primary Examiner H. BROOME, Assistant Examiner

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