The present invention relates to an electromagnetic relay comprising a motor assembly, a contact unit and means for attaching together said contact unit and said motor assembly, said contact unit comprising a base of insulating material provided with stationary and movable contacts and with output lugs connected to said stationary and movable contacts, respectively, and with further output luds, said motor assembly comprising a yoke having two flanges at right angles to each other, a core fixed to the inner face of a first one of said two flanges of said yoke, a coil mounted on said core and having a spool or frame with at least one end flange provided with electrically conducting metal tongues to which the ends of the coil wire are enchored, and a movable armature pivotally mounted to the free end of a second one of said two flanges to said yoke and having bent arms, said base of insulating material being fixed through said attaching means to the outer face of the second flange of said yoke, and said bent arms being operable to actuate said movable contacts when said coil is energized.
A relay of this type is described for example in French Pat. No. 1 527 178. In this known relay, the electric connections between the ends of the coil wire and said further output lugs are provided by two flexible lead-wires. To effect these electric connections, it is preferable for the metal tongues to be fixed into said end flangle of the frame of the coil so that the ends of the coil wire may be anchored to said tongues as described for example in French Pat. No. 2 291 590. These connections require soldering operations which are long and costly, and which cannot be very easily automated. There is also a risk that particles of resin coming from the core flux of a tin soldes wire are projected onto said stationary and movable contacts during the soldering operations. When multistrand wires are used as said flexible lead-wires, some strands of said multistrand wires may also not be caught in the solder joints and decrease the insulation.
Furthermore, the inner ends of said further output lugs for connecting the coil must be readily accessible when the base has been fixed to the yoke, so as to allow the soldering operations. This leads to placing the output lugs for the coil in an outer row of lugs, for example at the side of the base adjacent to the armature of the relay. Now it may desirable on the contrary to place the output lugs for the coil in an inner row of lugs, so as to allow the greatest possible length for the flexible metal strips which carry the movable contacts of the change-over contacts of the relay.
Finally, it is desirable for the motor assembly to be easily attached to, and possibly detached from the base of the contact unit, so as to simplify manufacture and maintenance. The actuation of the movable contacts by bent arms of the armature facilitates this coupling, but there remains the obstacle caused by the flexible lead-wires for connecting the coil.