| 摘要 |
A reciprocating cutting instrument includes an outer tube housing an inner reciprocating cutting blade. The cutting blade is engaged to a source of power, namely a motor, through a transmission and drive mechanism. This transmission and drive mechanism converts rotary drive movement of the motor to reciprocating movement of the cutting blade. A cam is provided that engages the spindle of the motor, the cam formed by a generally cylindrically shaped cam barrel with a cam channel defined in the outer surface of the barrel. A drive ball rides within the channel and is supported within a boss of a linear in-line driver. The in-line driver reciprocates within a bearing housed by a driver cartridge. Pressure between the drive ball and the cam channel is maintained by a set screw threaded into the boss in the in-line driver. As the motor rotates, the spindle, which is engaged to the cam, rotates the cam barrel. The rotation of the cam barrel causes the cam channel to pass underneath the drive ball, which forces the drive ball to follow the channel path. In one preferred embodiment, the channel path is in the form of a harmonic curve so that the drive ball will reciprocate through a particular stroke during a full rotation of the cam.
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