Vibrating means in a power drill

Abstract

Disclosed herein is a vibrator for use in a power drill having a housing and a spindle rotatably and axially movably supported by the housing. The vibrator comprises a rotary cam fitted on the spindle for rotation with the spindle, the rotary cam having a cam surface formed with at least one axially protruding ridge or serration; a clutch cam axially slidably fitted on the spindle and disposed behind the rotary cam, the clutch cam being restricted from rotating about the spindle and releasably engageable with the rotary cam, the clutch cam having a cam surface formed with at least one axially protruding ridge; and a spring adapted to urge the clutch cam toward the rotary cam so as to absorb the axial thrusting force applied to the spindle when the spindle is retracted. When the resilience of the spring overcomes the thrusting force, the rotary cam in motion is axially vibrated along with the spindle in conformity with the cam surface of the clutch cam, and on the other hand, when the thrusting force exceeds the resilience of the spring, the clutch cam is axially rearwardly moved in conformity with the cam surface of the rotary cam in motion, and then brought into collision with the rotary cam by virtue of the resilience of the spring so as to strike the rotary cam. With this construction, if excessive thrusting force is applied to the spindle when driven for rotation and vibration, it is absorbed to be changed into impacting force for effectively vibrating the spindle so as to reduce the load to the motor.