Provided is an electromagnetic contactor such that it is possible, while suppressing electromagnetic repulsion force generated between a movable contact and fixed contacts, to reduce the height of a contact device, and thus reduce the size of the electromagnetic contactor. The electromagnetic contactor includes a contact device (100) having a pair of fixed contacts (111), (112) disposed maintaining a predetermined distance and a movable contact (130) disposed so as to be connectable to and detachable from the pair of fixed contacts, and an electromagnet unit (200) having a movable plunger (215) that moves the movable contact of the contact device, the electromagnetic contactor having a hermetic chamber (240) enclosing the pair of fixed contacts, the movable contact, and the movable plunger, an external receptacle (101A), (101B) that covers the hermetic chamber and electromagnet unit, and a sound insulating resin layer (150) injected between the hermetic chamber and external receptacle and hardened.

A method of manufacturing a surface-mount encapsulated reed relay comprises providing a metal lead-frame 16,17 having conductors 16 for connecting the relay 10,11 to a circuit. A plastics plate 14 is insert-moulded to the lead-frame so that the conductors 16 extend through the plate. Unwanted lead-frame parts 17 are cut away on one side of the plate and a reed relay capsule 10,11 and operating coil 13 are connected thereto. A housing 23 is fitted to the plate 14 and embraces the capsule and coil and soft elastomeric material is injected into the housing. Any remaining unwanted lead-frame parts 17 are cut away externally of the housing and the exposed conductors are formed to lie in a common plane substantially co-planar with a face of the relay which will in use lie against a circuit board. In an alternative method, two plates 33,34 are insert-moulded to the lead-frame 27 in a spaced-apart disposition, a U-shaped housing 37 co-operating with the plates to form an enclosure for the relay capsule and coil.

The disclosed assembly may be used for fabricating a reed relay and includes a magnetically actuated switch and a bobbin. The switch defines an exterior surface and includes two terminals, and the switch provides a relatively low electrical resistance path between the two terminals when closed and provides a relatively high electrical resistance path between the two terminals when open. The bobbin defines an interior surface and an exterior surface, and the bobbin is disposed around the switch so that the bobbin interior surface contacts substantially all of a predetermined portion of the switch exterior surface.

A splice block for use with a condition responsive security switch is provided. The splice block (14) is generally cylindrical and mounted to the end of the switch (12) with terminals unitarily extending therebetween. The splice block includes a base (34) and a cover (36) which is mountable in alternate first and second positions on the base. The first position (Fig. 1) permits wires to be inserted into the splice block. Movement of the cover into the second position terminates the wires to terminals in the splice block.

A miniaturised magnetically-shielded potted electronic component such as a reed relay is manufactured by first producing a casing by etching a µ-metal sheet to produce a casing blank together with fold lines thereon, the blank then being folded to produce a casing part (10) completed by insulating plastics material end walls (21) located between turned-over end wall sections (16, 17) integral with the casing side walls (12, 13). The reed relay insert (24) and operating coil (25) are mounted on a lead frame (23) including pins (27, 28) and then the components are positioned within the casing (10) the lead frame (23) engaging grooves (22) in the end walls (21). The space within the casing surrounding reed relay is then filled with a potting compound and the relay completed by removing the salvage bar (31) from the lead frame (23).