| 摘要 |
A shaft is rotatable in a housing to several detented positions, established by a detent wheel and spring pressed detent balls, and is provided with a pinion gear which drives a gear rack on a valve carriage guided for linear movement along a spacer. A rubber valve on the carriage is movable across vacuum valve ports to perform vacuum switching functions. A bearing on the carriage moves along a slot in the spacer and carries an idler gear which rolls along a gear rack on the housing and drives a gear rack on an electrical carriage, slidable along the spacer. Fan and clutch contactors are movable with the electrical carriage across fixed contacts to perform electrical switching functions. The detent balls and springs can be inserted through access slots from outside the housing. The housing has two mounting members with latching hooks projecting forwardly for insertion into slots in a supporting panel. A boss on the housing around the shaft is insertable into an opening in the panel. The location of the boss forms a triangle with the locations of the hooks, whereby rotation of the housing on the panel is prevented. The hooks are located and configured to afford a tight interference fit with the panel. A uniquely located keying pin mates with a keying opening in the panel. Another uniquely located keying pin on the valve carriage mates with a keying opening in the valve to preclude assembly of an incorrect valve. An assembly fixture is adapted to be used for assembling the switch and is provided with an alignment pin adapted to extend through openings in the front housing wall, the clutch contactor and the electrical carriage as well as into a blind opening in the bearing, to insure correct assembly. A uniquely located keying tab on the valve carriage is movable through a keying slot in a flange on the housing, during the assembly, to preclude the assembly of an incorrect carriage.
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