| 摘要 |
1,212,163. Resistance motor controllers. SKIL CORP. 28 Jan., 1969 [29 May, 1968], No. 4618/69. Addition to 1,120,010. Heading H1S. A trigger-type controller for varying the speed of the motor of e.g. a portable electric tool is provided with a movable stop member which in one position allows maximum movement of the trigger and hence maximum motor speed and in another position abuts a fixed stop surface on movement of the trigger through a predetermined distance thus securing a predetermined speed lower than the maximum. In one embodiment a member 22 (Fig. 2) rotatable in trigger 16 by head 24a has a half round portion 26 which in one position (shown in Fig. 4) contacts casing surface 19 on movement of the trigger to limit such movement and in another position (Fig. 2) allows full movement of the trigger. In another embodiment a rotatable disc 54 (Fig. 7) has portions cut therefrom to form three different stop surfaces 57, 58, 59, the position of the disc governing which of these surfaces co-operates with casing surface 19-2 to limit movement of trigger 16-2. Three other embodiments are described in one of which a member (45, Fig. 5, not shown) is slidable on the trigger so that it can assume three different positions in each of which it cooperates with a different stop surface (40, 41 or 42) on the casing: In another embodiment (Figs. 9 and 10, not shown) a stop member is carried by a manually operable lever (60) pivoted on the casing and in the other embodiment (Figs. 11 and 12, not shown) a sleeve pivoted on the frame is provided with a projecting member (72) which can be swung into position to act as a stop. A locking button may be provided (Fig. 1, not shown). Partial movement of the trigger may provide a supply to the tool motor through a half-wave diode whilst full movement may connect the motor direct to the supply. |
