| 摘要 |
<p>1417737 Resistance motor controllers SKIL (NEDERLAND) NV 20 Feb 1973 [1 March 1972] 8317/73 Heading HIS [Also in Division H2] A portable electric tool has an on-off switch operated by a member 74 and, for motor speed control, a variable resistor device whose slider 37 is operated by a member 43, the members 74, 43 being slidably engaged with each other to be capable of independent operation. In the embodiment described member 74 has a rib (77, Fig. 12, not shown) which slides in a groove (46, Fig. 14, not shown) in member 43. Member 43 is actuated by a wheel 58, the shaft 56 of which has pinion teeth 55 which mesh with rack teeth (54) on member 43. Wiper contacts of slider 37 engage resistance strips on a ceramic board 28 carrying the circuit depicted in Fig. 18 (not shown). A detent spring 62 engages a portion 60 of wheel 58 to releasably hold it in a selected position. Movement of switch member 74 moves a contact 72 into "off", "on" and "full speed" positions, in the last of which the speed control circuit on board 28 is by-passed. Corresponding to these three positions are three apertures (80, 81, 82, Fig. 3, not shown) in a casing wall 14, which are selectively engaged by a detent (79, Fig. 13, not shown) or member 74.</p> |
