GB1576377A - Electromagnetic relays - Google Patents

Description

(54) IMPROVEMENTS RELATING TO ELECTROMAGNETIC RELAYS (71) We, THE PLESSEY COMPANY LIMITED, a British Company of 2/60 Vicarage Lane, Ilford, Essex, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to electromagnetic relays and relates more especially but not exclusively to electromagnetic relays of the so-called low-profile type.

According to the present invention there is provided an electromagnetic relay comprising an energising winding which in response to the energisation thereof produces actuation of an armature for the operation of relay contacts, said contacts being afforded by co-operating fixed and moving contact spring members of a contact spring set assembly, the moving contact spring members being displaced by means of a contacts actuating structure which engages the armature and which is acted on by a biasing blade spring the spring force of which is adjustable by screw adjustment means located between the actuating structure and the blade spring.

In carrying out the present invention the contacts actuating structure may comprise a moulded insulating structure having integral shoulders for actuating and for supporting contact springs of the relay. The blade spring may be secured at its ends to insulating spacer piles for clamping contact springs of contact spring set assemblies in predetermined spaced relationship.

By adjustment of the screw adjustment means the biasing spring pressure exerted on the armature can be adjusted according to requirements.

By way of example the present invention will now be described with reference to the drawings accompanying the Provisional Specification in which: Fig. 1 is a plan view of a low profile relay embodying the present invention; Fig. 2 is an end view of the relay taken in the direction of the arrow in Fig. 1 and, Fig. 3 is an exploded perspective view showing a contacts actuating structure and the biasing spring screw adjuster arrangement of the form used in the relay of Figs.

1 and 2.

Referring to the drawings the electromagnetic relay illustrated comprises an energising coil 1 wound on a bobbin 2 embodying a magnetic core 3. The magnetic core 3 has attached to it a magnetic yoke structure 4 on which pivots a generally L-shaped armature 5. This armature is attracted towards pole-piece 6 in response to the energisation of the energising coil 1 and may be provided with a residual stud 7 to prevent retention of the armature after de-energisation of the coil.

Secured to the yoke structure 4 by means of screws 8 and 9 are two piles 10 and 11 of insulating spacers serving to clamp the ends of fixed and moving contact springs of contact spring jassemblies. The springs of one assembly are indicated at 12 and 13, respectively. The contact springs clamped by the spacers of pile 10 which extend in the opposite direction to the springs clamped by the pile 11 are obscured from view by a contacts actuating structure 14.

As can be seen in Fig. .3, the contacts actuating structure 14 which is generally of the form shown In Fig. 11 comprises an insulating moulding having integral pairs of shoulders 15 and 16 which extend in opposite directions from Ithe two sides of the structure to serve the contact springs clamped by the respective piles 10 and 11.

The structure 14 has a cylindrical projection 17 which is arranged to project through a slot in the armature 5 so that an arcuate shoulder part 18 of the structure normally rests against the armature 5. The other end of the structure 14 is formed with a slot 19 which slidably receives a block 20 having channels 21 receiving structure 14. The block 20 has a threaded hole 22 extending therethrough for receiving an adjusting screw 23. This adjusting screw 23 extends through a hole 24 in a biasing blade spring 25. This blade spring 25 which is slightly V-shaped has cut-away portions 26 and 27 and apertured tongues 28, 29 are provided to facilitate the clamping of the ends of the biasing spring 25 to the tops of piles 10 and 11 by means of screws 8 and 9, the piles 10 and 11 being bridged by a slotted plate member 30 which slidingly receives the end of actuating structure 14.

It will be appreciated that the screw 23 as it is screwed further into the block 20 with the end of the screw bearing against the base of the slot 19 the block 20 will be caused to move away from the base of slot 19 and so force the spring 25 further away from the contacts actuating structure 14 so that the biasing force exerted on the structure 14 will be increased. This force may be reduced by unscrewing the adjusting screw 23.

It may here be mentioned that the block 21 could be replaced by a hexagonal nut for example which is held captive within a suitable recess provided in the contacts actuating structure 14. Moreover, it is also envisaged that the blade spring 25 could be formed to provide clip fixing of the spring on the bridging plate 30. In the latter case the apertured tongues 28 and 29 may be dispensed with.

From the foregoing description of one embodiment of the invention it will be readily appreciated that the present invention enables the biasing spring force exerted on the contacts actuating structure to be adjusted and thus the operating characteristics of the relay adjusted according to requirements.

WHAT WE CLAIM IS: 1. An electromagnetic relay comprising an energising winding which in response to the energisation thereof produces actuation of an armature for the operation of relay contacts, said contacts being afforded by co-operating fixed and moving contact spring members of a contact spring set assembly, the moving contact spring members being displaced by means of a contacts actuating structure which engages the armature and which is acted on directly by a biasing blade spring the spring force of which is adjustable by screw adjustment means located between the actuating structure and the blade spring.

2. An electromagnetic relay as claimed in claim 1, in which the contacts actuating structure comprises a moulded insulating structure having integral shoulders for actuating and for supporting contact springs of the relay.

3. An electromagnetic relay as claimed in claim 1 or claim 2, in which the blade spring is secured at its ends to insulating spacer piles for clamping contact springs of contact spring set assemblies in predetermined spaced relationship.

4. An electromagnetic relay substantially as hereinbefore described with reference to the drawings accompanying the Provisional Specification.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (4)

**WARNING** start of CLMS field may overlap end of DESC **. other end of the structure 14 is formed with a slot 19 which slidably receives a block 20 having channels 21 receiving structure 14. The block 20 has a threaded hole 22 extending therethrough for receiving an adjusting screw 23. This adjusting screw 23 extends through a hole 24 in a biasing blade spring 25. This blade spring 25 which is slightly V-shaped has cut-away portions 26 and 27 and apertured tongues 28, 29 are provided to facilitate the clamping of the ends of the biasing spring 25 to the tops of piles 10 and 11 by means of screws 8 and 9, the piles 10 and 11 being bridged by a slotted plate member 30 which slidingly receives the end of actuating structure 14. It will be appreciated that the screw 23 as it is screwed further into the block 20 with the end of the screw bearing against the base of the slot 19 the block 20 will be caused to move away from the base of slot 19 and so force the spring 25 further away from the contacts actuating structure 14 so that the biasing force exerted on the structure 14 will be increased. This force may be reduced by unscrewing the adjusting screw 23. It may here be mentioned that the block 21 could be replaced by a hexagonal nut for example which is held captive within a suitable recess provided in the contacts actuating structure 14. Moreover, it is also envisaged that the blade spring 25 could be formed to provide clip fixing of the spring on the bridging plate 30. In the latter case the apertured tongues 28 and 29 may be dispensed with. From the foregoing description of one embodiment of the invention it will be readily appreciated that the present invention enables the biasing spring force exerted on the contacts actuating structure to be adjusted and thus the operating characteristics of the relay adjusted according to requirements. WHAT WE CLAIM IS:

1. An electromagnetic relay comprising an energising winding which in response to the energisation thereof produces actuation of an armature for the operation of relay contacts, said contacts being afforded by co-operating fixed and moving contact spring members of a contact spring set assembly, the moving contact spring members being displaced by means of a contacts actuating structure which engages the armature and which is acted on directly by a biasing blade spring the spring force of which is adjustable by screw adjustment means located between the actuating structure and the blade spring.

2. An electromagnetic relay as claimed in claim 1, in which the contacts actuating structure comprises a moulded insulating structure having integral shoulders for actuating and for supporting contact springs of the relay.

3. An electromagnetic relay as claimed in claim 1 or claim 2, in which the blade spring is secured at its ends to insulating spacer piles for clamping contact springs of contact spring set assemblies in predetermined spaced relationship.

4. An electromagnetic relay substantially as hereinbefore described with reference to the drawings accompanying the Provisional Specification.