| 摘要 |
A bit retention device includes a shaft having a sidewall defining a hexagonal cavity extending from a first end thereof and a ball groove extending through the sidewall and communicating with the hexagonal cavity. A ball is disposed in the ball groove and a ball spring engages the ball and biases the ball toward the first end. An actuator sleeve surrounding the shaft includes an internal ramp engaging the ball. The internal ramp includes a shallow ramp portion having a first angle of inclination with respect to a center axis and a steep ramp portion having a second angle of inclination with respect to said center axis of said shaft that is greater than the first angle of inclination. A spring biased plunger assembly is disposed in the bore for biasing a bit received in the bore in a direction toward the insertion end.
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