GB1600762A - Electromagnetic relay - Google Patents

Description

(54) ELECTROMAGNETIC RELAY (71) We, LUCAS INDUSTRIES LIMITED, a British Company of Great King Street, Birmingham B 19 2XF, 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 an electromagnetic relay.

In a previously proposed electromagnetic relay the electromagnet winding is wound on a moulded synthetic resin former and the relay includes an electrically insulating base to which the former is secured. The former is secured to the base by means of a pair of electrical terminal members which extend through appropriately positioned apertures in the former and the base.

Part of the metal frame of the electromagnet is carried by the former and an electrical connection is required between the frame and a further terminal member secured to the base. Such a mode of construction is very convenient in many respects but suffers from the disadvantage that the tolerances involved in the manufacture of the various components must be kept to a minimum if the parts are to be assembled to one another and to the base with a minimum of problems. For example, unless the frame, the former, and the additional terminal to which the frame is to be secured, together with the base, are manufactured with minimal tolerance, then it is conceivable that the frame will not lightly abut the terminal or an extension thereof. if as a result of tolerances, the frame is spaced from the terminal or the extension then it will be difficult to weld the two together to establish the electrical connection without imparting disadvantageous stress to the assembly. On the other hand if the two are faced tightly against one another then some distortion will inevitably occur.

It is an object of the present invention to provide an electromagnetic relay which is simple and convenient to assemble and wherein during assembly mislocation of the former relative to at least one other component of the relay can be accommodated.

An electromagnetic relay according to the invention includes an electrically insulating base, a former on which the electromagnet winding of the relay is wound, and at least one electrical terminal member securing the former to the base, said electrical terminal member extending through an aperture in a part of the former, and extending through the base so as to be accessible from the face of the base remote from the former, said aperture in said part of the former having a greater dimension in at least one direction than the part of the terminal member which extends therethrough so that, during assembly of the former to the base, the former can be moved relative to the base in said direction.

Preferably, the former or a part thereof is formed with a second aperture similar to the first mentioned aperture, and a second terminal member similar to the first mentioned terminal member extends through the second aperture and the base and serves also to secure the former to the base.

Desirably the or each terminal member is in the form of a blade terminal member and the or each aperture is in the form of an elongate slot.

One example of the invention is illustrated in the accompanying drawings wherein: Figure 1 is a sectional view of an assembled electromagnetic relay; Figure 2 is a view in the direction of arrow A in Figure 1; Figure 3 is a side elevational view of part of the relay shown in Figure 1; Figure 4 is a plan view of the former of the relay shown in Figure 1; and Figure 5 is a sectional view on the line 5-5 in Figure 1.

Referring to the drawings the electromagnetic relay includes a moulded synthetic resin base 11 having therein five slots 12 through which extend respective electrical blade terminal members 13, 14, 15, 16, 17.

The terminal members 13-17 project from one face of the base 11 the outer face in use, for connection to respective socket connectors.

The base 11 is rectangular, and engaged with the base 11 and defining therewith a generally cuboidal enclosure is a hollow sheet metal casing 18. The casing 18 is formed at its free edge with a plurality of tags which in use, are bent over in use to engage in recesses in the base 11 to secure the casing 18 to the base 1. The terminal members 13-17 extend through the base 11 and into the enclosure defined by the casing 18.

Within the enclosure the terminal members 15, 16 include integral portions indicated by the suffix a which are bent at right angles so as to lie parallel to the base 11. The portion 16a lies in contact with the inner surface of the base 11 and the portion 15a overlies the portion 16a and is spaced therefrom. The terminal member 17 includes an integral extension 1 7a which extends at right angles to the base 11.

Disposed within the enclosure is a moulded synthetic resin former 19 generally in the form of a hollow cylindrical spool upon which the electromagnet winding 21 of the relay is wound. The former 19 is positioned with its longitudinal axis extending at right angles to the plane of the base 11 and extending within the bore 22 of the former 19 is a ferrous metal electromagnet pole 23.

The pole 23 is secured to one limb 25 of an L-shaped ferrous metal frame member 24, the pole 23 extending parallel to and spaced from the other limb 26 of the frame member 24. The limb 25 of the frame 24 extends across the end face of the former 19 remote from the base 11 and the limb 26 extends parallel to the axis of the former 19 towards the base 11. During assembly the limb 26 is to be welded to the extension 17a of the terminal member 17.

The end of the former 19 presented to the base 11 includes an integral flange 27 extending at right angles to the axis of the former.

The flange 27 includes a pair of diametrically opposed legs 28 which extend parallel to the axis of the former and each leg 28 includes a foot 29 having therein an aperture 31.

The feet 29 engage the base 11, and thus serve to space the flange 27 from the base 11.

The armature 32 of the relay extends from the limb 26 between the flange 27 and the base 11 and passes adjacent the free end of the pole 23. At one end the armature 32 is connected to the limb 26 of the frame 24 by means of a conductive phosphor-bronze spring strip 33, the spring strip 33 carrying the armature 32 and terminating at its end remote from the limb 26 between the portions 15a and 16a of the terminal members 15. 16. The free end of the strip 33 carries a pair of contact pieces presented to the portion 15a, 1 6a respectively.

The apertures 31 in the feet 29 are long and narrow, and are paralleled. Additionally the apertures are aligned with the apertures 12 of the base through which the terminal members 13, 14 extend. The innermost ends of the terminal members 13, 14 are generally T-shaped and the terminal members extend through the apertures 31. The length dimension of the apertures 31 is greater than the equivalent (width) dimension of the parts of ther terminal members 13, 14 which extend therethrough, but the equivalent dimension of the innermost end regions of the terminal members 13, 14 is greater than the length dimension of the apertures 31. Thus the transversely projecting parts 13a, 14a of the terminal members 13, 14 overlie the upper surface of their respective foot 29 and when the terminal members 13. 14 are anchored to the base, the terminal members serve to secure the former 19 in position relative to the base. In addition, the terminal members 13, 14 include extensions indicated in the drawing by the suffix b to which the ends of the winding 21 are respectively connected.

The spring strip 33 normally urges the armature 32 away from the pole 23 so that the appropriate contact piece at the free end of the strip 33 engages the portion 16a thus electrically connecting the terminal members 16, 17. However, when an electrical circuit is completed between the terminal members 13, 14 the electromagnet winding 21 is energised and the armature 32 is attracted to the pole 23 so that the appropriate contact piece engages the portion 15a of the terminal member 15 thereby electrically interconnecting the terminal members 17, 15 and breaking the electrical connection between the terminal members 17, 16.

The relay is assembled in the following manner. With the casing 18 removed the terminal members 16, 17 are assembled to the base and are staked to secure them in position relative to the base. A sub-assembly comprising the former 19 together with the winding 21 the pole 23, the frame member 24 and the terminal members 13, 14 is then located on the base 11 with the feet 29 engaging the base and the terminal members 13, 14 extending through the base. At this stage the spring strip 33 carrying the armature 32 is already secured to the limb 26 of the frame member 24. The apertures 31 are aligned with the apertures 12 through which the terminal members 13, 14 extend. The transverse extension of the terminal members 13, 14, indicated by the suffix a in the drawings, engage the surfaces of the feet 29 remote from the base 11. At this stage however the terminals 13, 14 are not staked to secure them to the base.

In order that a welded connection can be produced between the extension 17a of the terminal member 17 and the limb 26 of the frame 24 it is necessary for the limb 26 to abut the extension 17a. As a result of tolerances involved in the manufacture of the various components it can occur that the frame member 26 is spaced from the extension 17a or bears against the extension 17a sufficiently hard to cause flexure of the components. Either of these situations can be remedied before the sub-assembly including the former 19 is fixed in position by sliding the sub-assembly relative to the base and the terminal members as permitted by the lengthwise clearance between the ends of the apertures 31 and the parts of the terminal members 13, 14 which extend therethrough.

This facility for adjustment permits the subassembly to be positioned so that the limb 26 just abuts the extension 17a. Thereafter the weld between the limb 26 and the extension 17a is made and the terminal members 13, 14 are loaded in a direction to pull the feet 29 firmly against the base and the terminal members are then staked to secure them in position relative to the base thus holding the sub-assembly including the former 19 in position relative to the base.

It will be appreciated that in the absence of the facility for adjusting the position of the sub-assembly relative to the base, then in the situation where the extension 17a and the limb 26 are spaced apart the extension 17a would need to be flexed to engage the limb 26 prior to ewlding, and of course the flexure would result in a stressed assembly which in turn could result in distortion of the assembly and mislocation of the contact pieces of the strip 33 relative to the contact portions 15a, 16a. Similarly, where the limb 26 pressed hard against the extensions 17a an undesirably stressed assembly would be produced.

It will be appreciated that the extension of the apertures 31 in relation to the dimension of the parts of the terminal members passing through the slots 31 is arranged to provide adjustment movement in the appropriate direction. In a modification where the extension 17a is to abut an edge of the limb 26 rather than a face of the limb 26 the length dimension of the aperture 31 is substantially equal to the width dimension of the parts of the terminal members 13, 14 passing therethrough but the width dimension of the apertures 31 is larger than the thickness dimension of the parts of the terminal members passing through the apertures so that the position of the sub-assembly may be adjusted relative to the terminal members 13, 14 in the appropriate direction to move an edge of the limb 26 towards or away from the extension 17a.

It will be understood that if desired the clearances between the terminal members 13, 14 and the walls of the apertures 31 can be arranged to facilitate movement in other directions, or in more than one direction.

WHAT WE CLAIM IS: 1. An electromagnetic relay including an electrically insulating base, a former on which the electromagnet winding of the relay is wound, and at least one electrical terminal member securing the former to the base, said electrical terminal member extending through an aperture in a part of the former, and extending through the base so as to be accessible from the face of the base remote from the former, said aperture in said part of the former having a greater dimension in at least one direction that the part of the terminal member which extends therethrough so that, during assembly of the former to the base, the former can be moved relative to the base in said direction.

2. An electromagnetic relay as claimed in claim 1 wherein the former or part thereof is formed with a second aperture similar to the first mentioned aperture and a second terminal member similar to said first terminal member extends through the second aperture and the base and serves also to secure the former to the base.

3. An electromagnetic relay as claimed in claim 1 or claim 2 wherein the or each terminal member is in the form of a blade terminal member and the or each aperture is in the form of an elongate slot.

4. An electromagnetic relay substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

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

Claims (4)

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

   frame member 26 is spaced from the extension 17a or bears against the extension 17a sufficiently hard to cause flexure of the components. Either of these situations can be remedied before the sub-assembly including the former 19 is fixed in position by sliding the sub-assembly relative to the base and the terminal members as permitted by the lengthwise clearance between the ends of the apertures 31 and the parts of the terminal members 13, 14 which extend therethrough.

   This facility for adjustment permits the subassembly to be positioned so that the limb 26 just abuts the extension 17a. Thereafter the weld between the limb 26 and the extension 17a is made and the terminal members 13, 14 are loaded in a direction to pull the feet 29 firmly against the base and the terminal members are then staked to secure them in position relative to the base thus holding the sub-assembly including the former 19 in position relative to the base.

   It will be appreciated that in the absence of the facility for adjusting the position of the sub-assembly relative to the base, then in the situation where the extension 17a and the limb 26 are spaced apart the extension 17a would need to be flexed to engage the limb 26 prior to ewlding, and of course the flexure would result in a stressed assembly which in turn could result in distortion of the assembly and mislocation of the contact pieces of the strip 33 relative to the contact portions 15a, 16a. Similarly, where the limb 26 pressed hard against the extensions 17a an undesirably stressed assembly would be produced.

   It will be appreciated that the extension of the apertures 31 in relation to the dimension of the parts of the terminal members passing through the slots 31 is arranged to provide adjustment movement in the appropriate direction. In a modification where the extension 17a is to abut an edge of the limb 26 rather than a face of the limb 26 the length dimension of the aperture 31 is substantially equal to the width dimension of the parts of the terminal members 13, 14 passing therethrough but the width dimension of the apertures 31 is larger than the thickness dimension of the parts of the terminal members passing through the apertures so that the position of the sub-assembly may be adjusted relative to the terminal members 13, 14 in the appropriate direction to move an edge of the limb 26 towards or away from the extension 17a.

   It will be understood that if desired the clearances between the terminal members 13,

   14 and the walls of the apertures 31 can be arranged to facilitate movement in other directions, or in more than one direction.

   WHAT WE CLAIM IS: 1. An electromagnetic relay including an electrically insulating base, a former on which the electromagnet winding of the relay is wound, and at least one electrical terminal member securing the former to the base, said electrical terminal member extending through an aperture in a part of the former, and extending through the base so as to be accessible from the face of the base remote from the former, said aperture in said part of the former having a greater dimension in at least one direction that the part of the terminal member which extends therethrough so that, during assembly of the former to the base, the former can be moved relative to the base in said direction.
2. 2. An electromagnetic relay as claimed in claim 1 wherein the former or part thereof is formed with a second aperture similar to the first mentioned aperture and a second terminal member similar to said first terminal member extends through the second aperture and the base and serves also to secure the former to the base.
3. 3. An electromagnetic relay as claimed in claim 1 or claim 2 wherein the or each terminal member is in the form of a blade terminal member and the or each aperture is in the form of an elongate slot.
4. 4. An electromagnetic relay substantially as hereinbefore described with reference to and as shown in the accompanying drawings.