Retraction mechanism with clutch-less drive for use with surgical apparatus
A retraction mechanism allows the full distal retraction of the firing drive from various positions. The retraction mechanism has been developed for use with a hand held surgical apparatus. An embodiment of the retraction mechanism includes a drive member, a first pulley, a second pulley, and a firing drive. The drive mechanism is configured to be driven by a motor. The first pulley is configured to rotate when the motor drives the drive mechanism. The second pulley is movable relative to the first pulley between a proximal position and a distal position. The firing drive is movable relative to the first pulley between proximal and distal positions. In operation, the first pulley rotates in a first direction in response to a distal translation of the firing drive and wherein the firing drive moves proximally upon rotation of the first pulley in a second direction.
1. A retraction mechanism for use with a surgical apparatus, comprising:
a shaft defining a longitudinal axis;
a worm disposed in mechanical cooperation with the shaft and configured to rotate about the longitudinal axis;
a worm gear operatively associated with the worm, the worm gear configured to rotate about a worm gear axis in response to rotation of the worm about the longitudinal axis, wherein rotation of the worm gear about the worm gear axis causes a firing drive of the surgical apparatus to move longitudinally;
a pulley operatively connected to the worm gear; and
a flexible member interconnecting the pulley and the firing drive of the surgical apparatus.
2. The retraction mechanism according to claim 1 , wherein the shaft is configured to rotate about the longitudinal axis.
3. The retraction mechanism according to claim 2 , wherein the worm is configured to rotate about the longitudinal axis concomitantly with the shaft.
4. The retraction mechanism according to claim 1 , wherein the worm is configured to move longitudinally relative to the shaft.
5. The retraction mechanism according to claim 1 , wherein rotation of the worm gear in a first direction about the worm gear axis moves the firing drive proximally.
6. The retraction mechanism according to claim 1 , wherein the worm and the shaft are coaxial.
7. The retraction mechanism according to claim 1 , wherein at least a portion of the worm radially surrounds the shaft.
8. The retraction mechanism according to claim 1 , wherein the worm includes a thread formed thereabout.
9. The retraction mechanism according to claim 1 , further including a spring motor operatively connected to the flexible member, wherein the spring motor is configured to maintain the flexible member in tension.
10. The retraction mechanism according to claim 1 , further including a post rotatably connected to the worm gear, wherein the post is configured to rotate in a first direction when the worm gear rotates in the first direction.
11. The retraction mechanism according to claim 1 , wherein the worm is configured to move along the first shaft upon rotation of the first shaft.
12. The retraction mechanism according to claim 1 , wherein the shaft includes a plurality of keys, the plurality of keys configured to engage the worm to rotatably fix the worm relative to the shaft.
13. The retraction mechanism according to claim 1 , further including a frame supporting at least a portion of the shaft.
14. The retraction mechanism according to claim 1 , further including a motor configured to lock rotation of the shaft when the motor is in an off position.