| 摘要 |
A pair of insulating base halves (26,28) are adapted for mutual engagement along respective open sides, one base half (26) containing stationary contacts (30,32,34) and an electrical bussing element (30) structurally interlocked with that base half upright against an interior wall and the other base half containing a speed control circuit board (40) disposed in an upright position along an opposite interior wall and electrical connectors (56,58) biased into electrical engagement with the circuit board and forming push-in lead connectors with the stationary contacts and bussing element, a movable contact carrier (38) disposed between the base halves for sliding movement and having a movable contactor (64) engaging the stationary contacts and a wiping contact (66) engaging variable resistance (44,46) elements on the printed circuit board, the two base halves being interlocked (26k,28e) together along a lower edge and retained together along an upper edge by inserting them into a hollow housing (2) containing a depressible trigger operator (4,18) the insertion effecting a driving connection (18d,38k) between the movable contact carrier and an internal member (18) of the trigger operator, the internal member having a shaft (18a) projecting through an opening (2b) in an end wall of the housing which has a seal retaining cage (2c) formed thereon around the opening (26) the internal member being retractible to position the end of the shaft (18a) flush with the end wall for permitting a seal (22) and seal retaining cap (24) to be inserted to said cage, and an external trigger operator member (4) affixed to the end of the shaft, the external member having an interlocking structure (4d) formed therein for cooperation with a reversing switch lever (14) which overlies the external trigger operator member and has a depending projection (14d) engaging the interlocking structure (4d) in a center position to prevent depression of the trigger.
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