Method and apparatus for manufacturing sealed magnetic reed contact devices

摘要

1,013,913. Electromagnetic relays. STANDARD TELEPHONES & CABLES Ltd. Sept. 14, 1962 [Sept. 21, 1961], No. 35186/62. Heading H2B. The air gap between the reeds of a sealed magnetic contact device is adjusted after sealing one reed in position by rotating the other reed prior to sealing it in position. Reeds 2, 21 mounted in magnetic holding devices 1, 11 and a glass tube 3 mounted in a holding device 111 are moved into alignment with heaters 10, 11, an adjusting winding 12 and rotatable clamps 5 and 6. The reeds 2, 21 are gripped by the clamps 5, 6 respectively and the tube by a clamp 13 before the holding devices 1, 11 and 111 are removed. The clamps 5, 6 are rotated about axes 17, 171 respectively until the reeds 2, 21 engage contacts 15, 16 which are connected in control circuits for the clamps 5 and 6. The contacts 15, 16 ensure that the inner ends of the reeds are exactly parallel. The contacts 15, 16 are withdrawn and the tube 3, adjusting coil 12 and heaters 10 and 11 are lowered over reed 21. The reed 2 is then lowered into the tube. Air is driven out of the tube 3 by a continuous stream of inert gas which enters by way of a capsule 7 enclosing the clamp 6. The upper heater 10 is switched on and the adjusting coil 12 energized so that the reeds engage. When the reed 2 is sealed in position the heater 10 is switched off and the clamp 5 removed. The lower heater 11 is switched on to pre-melt the lower end of the tubes and the winding 12 is de-energized when the upper seal has hardened. Clamp 6 is rotated to cause disengagement of the reeds and the tube 3 and upper reed 21 are moved horizontally so that the sealing point 171 of reed 2 is in the centre of the tube. A sensing probe 18 is connected to reed 2 in a circuit comprising reed 2, the probe, a power source, a relay, lamp 6, and reed 21. The winding 12 is energized, heater 11 switched off and clamp 6 rotated until reeds 2, 21 engage. The winding 12 is now deenergized and the heater 11 is switched on to complete the lower seal. The above adjustment can be performed mechanically by rotating the clamp 6 until the reeds engage with winding 12, de-energized and then displacing the reeds mechanically.