| 摘要 |
1,063,648. Change-speed control. BLACK & DECKER MANUFACTURING CO. June 19, 1964 [June 20, 1963], No. 25390/64. Heading F2D. A two-speed constant-mesh gear comprises gears 30, 31 freely mounted on an output shaft 32 and biased by springs 41, 39 towards engagement with a clutch pin 35 fast with the output shaft. An eccentric 45 fast with a shaft 44 is rotatable to positions selectively disengaging the gears from the clutch pin and to a neutral position in which both gears are disengaged. The shaft 44 is axially slidable in a casing 15 and is biased to its innermost position by a spring 47. The shaft 44 is actuated by a lever 49 which is pivotally mounted by way of an integral bridge portion 51 engaging a slot 48 in the shaft so that the lever can be folded flat against the bottom of a recess 52 formed in the casing 15, in which position a projection 53 of the casing engages an opening 50 in the lever to prevent rotation of the shift shaft 44. On pivoting the lever 49 about bridge 51, lugs 54 of the lever engage a wear washer 55 in the recess 52 and raise the shift shaft 44 slightly against the pressure of the spring 47. The shaft 44 can then be rotated by the lever to clutch the selected gear 30, 31 to the output shaft, and thereafter the lever be folded flat to prevent accidental disengagement. Opposite sides of the lever are stamped H and L to indicate high and low ratios. The gearing comprises an input shaft 21 geared to an intermediate shaft 25 having gears 29, 28 constantly meshing the gears 30, 31. The arrangement is particularly intended for a two-speed electric drill; with the lever flat in the recess 52 it does not interfere with the securing of attachments to the drill for converting the drill to perform other operations. |
