Surgical retractor and bidirectional ratchet
A surgical device includes a ratchet having pawls biased to a locked position in which the pawls prevent movement of a ratchet body along a rack. A pinion and a cam disc of the ratchet cooperate to selectively release the pawls from the rack and impart ratcheted movement of the ratchet body along the rack. Rotation of a handle rotates the pinion and the cam disc. Due to such rotation, the cam disc periodically releases the pawls from the rack, and the pinion imparts movement of the ratchet body along the rack during the periodic release of the pawls.
1 . A retractor system for use with a frame member, the retractor system comprising:
a ratchet comprising a ratchet body, a rack comprising a rack first end, a rack second end, and rack teeth along a surface of the rack between the rack first end the rack second end, a pinion engaged with the rack teeth, a first pawl engaged with the rack teeth, a second pawl engaged with the rack teeth, a cam disc comprising cam disc protrusions, and a handle coupled to the pinion and the cam disc;
a retractor connector coupled to the rack first end and configured to receive a retractor blade and secure the retractor blade to the rack; and
a clamp coupled to the ratchet body and configured to secure the ratchet body to the frame member;
wherein rotation of the handle rotates the pinion and the cam disc;
wherein rotation of the cam disc causes the cam disc protrusions to engage the first pawl and the second pawl and release the first pawl and the second pawl from the rack teeth; and
wherein rotation of the pinion imparts movement of the ratchet body along the rack.
2 . The retractor system of claim 1 , comprising one or more springs that bias the first pawl and the second pawl toward engagement with the rack teeth.
3 . The retractor system of claim 2 , wherein rotation cam disc causes of the cam disc protrusions to disengage the first pawl and the second pawl and permit the one or more springs to bias the first pawl and the second pawl toward engagement with the rack teeth.
4 . The retractor system of claim 1 , comprising a release button that in response to being pressed disengages the first pawl and the second pawl from the rack teeth.
5 . The retractor system of claim 1 , wherein the cam disc protrusions are spaced in a manner that periodically engages and disengages the first pawl and the second pawl from the rack teeth as the rack traverses through the ratchet body.
6 . The retractor system of claim 1 , wherein the cam disc protrusions are spaced in a manner that periodically moves portions of the first pawl and the second pawl that engage the rack teeth in a direction away from the rack teeth.
7 . The retractor system of claim 1 , wherein the cam disc protrusions are spaced in a manner that periodically permits the first pawl and the second pawl to pass over the rack teeth.
8 . The retractor system of claim 1 , wherein:
the cam disc comprises a cam disc recess;
the cam disc protrusions are along an inner wall of the cam disc recess;
the first pawl comprises a first pawl tab that extends into the cam disc recess and engages one or more of the cam disc protrusions; and
the second pawl comprises a second pawl tab that extends into the cam disc recess and engages one or more of the cam disc protrusions.
9 . A retractor system, comprising:
a frame assembly comprising one or more posts and one or more frame members coupled to the one or more posts;
a ratchet coupled to the one or more frame members, the ratchet comprising a rack, a pinion, a first pawl, a second pawl, a cam disc, and a handle; and
a retractor blade coupled to a first end of the rack;
wherein the handle is coupled to the pinion and the cam disc such that rotation of the handle rotates the cam disc and pinion;
wherein rotation of the cam disc causes the cam disc to engage the first pawl and the second pawl and release the first pawl and the second pawl from the rack; and
wherein rotation of the pinion imparts ratchet movement of the rack and the retractor blade with respect to the one or more frame members.
10 . The retractor system of claim 9 , comprising one or more springs that bias the first pawl and the second pawl toward engagement with the rack.
11 . The retractor system of claim 10 , wherein rotation of the cam disc causes the cam disc to disengage the first pawl and the second pawl and permit the one or more springs to bias the first pawl and the second pawl toward engagement with the rack.
12 . The retractor system of claim 9 , wherein the ratchet comprises a release button that in response to being pressed move portions of the first pawl and the second pawl that engage the rack in a direction away from the rack.
13 . The retractor system of claim 9 , wherein the cam disc comprises cam disc protrusions that are spaced to periodically engage and disengage the first pawl and the second pawl from the rack as the cam disc is rotated.
14 . The retractor system of claim 9 , wherein the cam disc comprises cam disc protrusions that are spaced to periodically move portions of the first pawl and the second pawl that engage the rack in a direction away from the rack as the cam disc is rotated.
15 . The retractor system of claim 9 , wherein the cam disc comprises cam protrusions that are spaced to periodically permit the first pawl and the second pawl to pass over the rack as the cam disc is rotated.
16 . The retractor system of claim 9 , wherein:
the cam disc comprises a cam disc recess and cam disc protrusions along an inner wall of the cam disc recess;
the first pawl comprises a first pawl tab that extends into the cam disc recess and engages one or more of the cam disc protrusions; and
the second pawl comprises a second pawl tab that extends into the cam disc recess and engages one or more of the cam disc protrusions.
17 . A retractor system, comprising:
a ratchet comprising a ratchet body, a rack that passes through the ratchet body, a pinion that engages rack teeth of the rack, a first pawl comprising a first pawl distal portion that engages the rack teeth, a second pawl comprising a second pawl distal portion that engages the rack teeth, a cam disc, and a handle; and
a retractor blade coupled to a first end of the rack;
wherein the handle is coupled to the pinion and the cam disc and rotates the pinion in unison with the cam disc; and
wherein rotation of the cam disc causes the cam disc to press a first pawl proximal portion of the first pawl and a second pawl proximal portion of the second pawl which causes the first pawl distal portion and the second pawl distal portion to pivot away from the rack teeth; and
wherein rotation of the pinion moves the ratchet body along the rack.
18 . The retractor system of claim 17 , comprising one or more springs that bias the first pawl and the second pawl such that the first pawl distal portion and the second pawl distal portion pivot towards the rack teeth.
19 . The retractor system of claim 17 , wherein the ratchet comprises a release button that presses the first pawl proximal portion and the second pawl proximal portion and causes the first pawl distal portion and the second pawl distal portion to pivot away from the rack teeth.
20 . The retractor system of claim 17 , wherein:
the cam disc comprises a cam disc recess and cam disc protrusions along an inner wall of the cam disc recess;
the first pawl proximal portion comprises a first pawl tab that extends into the cam disc recess and engages one or more of the cam disc protrusions; and
the second pawl proximal portion comprises a second pawl tab that extends into the cam disc recess and engages one or more of the cam disc protrusions.