Surgical stapling instrument having preloaded firing assistance mechanism

• US 20070068990A1
• Filed: 09/29/2005
• Published: 03/29/2007
• Est. Priority Date: 09/29/2005
• Status: Active Grant

• Current Assignee: Cilag Gmbh International (Johnson & Johnson)
• Original Assignee: Ethicon Endo-Surgery, Inc. (Johnson & Johnson)
• Inventors: Swayze, Jeffrey, Timperman, Eugene, Shelton, Frederick, Fugikawa, Leslie
• Granted Patent: US 7,357,287 B2
• Time in Patent Office: Days
• US Class Current: 227/175.100
• CPC Class Codes: A61B 17/07207 the staples being applied sequentially
• CPC Class Codes: A61B 2017/00398 using powered actuators, e.g. stepper motors, solenoids
• CPC Class Codes: A61B 2017/2923 Toothed members, e.g. rack and pinion
• CPC Class Codes: A61B 2017/320052 Guides for cutting instruments

Abstract

A surgical severing and stapling instrument clamps tissue in a staple applying assembly comprising a lower jaw of an elongate channel holding a staple cartridge and a pivotally opposed upper jaw (anvil). A firing handle drives a rack in a handle connected to a firing rod and bar that pass through an elongate shaft and into the staple applying assembly to sever and staple tissue. Upon release of the firing handle, a retraction spring assists in withdrawing the rack and other firing components. To advantageously assist in firing, a spring biased plunger is cocked prior to firing to impart assistance upon depression of the firing trigger. Alternatively, a torsion coil spring ratchet mechanism is preloaded to act through a gear into the rack to assist. As a further alternative, a retraction spring is preloaded and disengaged until the rack is fully fired.

Claims

1. A surgical instrument, comprising:

a handle;

an elongate implement portion;

a firing mechanism, comprising;

a distal portion received for longitudinal reciprocating motion in the elongate implement portion, and

a proximal portion received in the handle for reciprocating movement between an unfired position and a fired position and coupled to the distal portion to transfer the related longitudinal reciprocating motion;

a firing actuator movably attached to the handle and coupled to move the proximal portion of the firing mechanism from the unfired position to the fired position; and

an assistance mechanism, comprising;

a follower member received in the handle, proximate and aligned for movement between the unfired and fired positions of the proximal portion of the firing mechanism,

a biasing member operatively configured to urge the follower member in a selected direction between unfired and fired positions and to be preloaded by movement of the shuttle in an opposing direction, and

an engagement mechanism operatively configured, in response to the proximal portion of the firing mechanism beginning movement in the selected direction, to release the follower member that is preloaded by the biasing member and engaged to the proximal portion of the firing mechanism.

2. The surgical instrument of claim 1, wherein the follower member comprises a linearly moving shuttle, the biasing member comprising a linear spring attached between the handle and the linearly moving shuttle.

3. The surgical instrument of claim 2, wherein the linear spring comprises a tension spring.

4. The surgical instrument of claim 2, wherein the linear spring comprises a compression spring.

5. The surgical instrument of claim 1, wherein the proximal portion of the firing mechanism comprises a rack, the follower member comprises a gear train, and the biasing member comprises a torsion coil spring biased ratchet gear attached to the handle.

6. The surgical instrument of claim 1, wherein the selected direction for assistance is firing from the unfired position to the fired position, the engagement mechanism further comprising a brake coupled to the proximal portion of the firing mechanism and responsive to actuation of the firing actuator to release.

7. The surgical instrument of claim 6, wherein the brake comprises a leveraged brake pad having a pivot point moved relative to the handle in response to actuation of the firing actuator to move the leveraged brake pad out of coupled engagement with the proximal portion of the firing mechanism.

8. The surgical instrument of claim 6, wherein the brake comprises a brake arm having a rotated portion positioned to rotate into coupled engagement with the proximal portion of the firing mechanism in response to actuation of the firing actuator.

9. The surgical instrument of claim 6, wherein the follower member comprises a shuttle, the engagement mechanism further comprising a locking cam biased into engagement with the proximal portion of the firing mechanism, and the handle comprising a disengaging cam positioned to move the locking cam out of engagement with the proximal portion of the firing mechanism as the shuttle approaches the fired position.

10. The surgical instrument of claim 6, further comprising a spring attached between the handle and the proximal portion of the firing mechanism to impart a retraction bias.

11. The surgical instrument of claim 10, wherein the spring comprises a tension spring having an attachment point to the handle proximal to an attachment point to the proximal portion of the firing mechanism.

12. The surgical instrument of claim 1, wherein the selected direction is retraction from the fired position to the unfired position, the follower member comprises a shuttle, the engagement mechanism further comprises a locking cam responsive to movement of the shuttle to the fired position to engage the handle resisting corresponding preloading of the biasing member and responsive to movement of the proximal portion of the firing mechanism approaching the fired position to disengage from the handle and to engage the proximal portion of the firing mechanism.

13. The surgical instrument of claim 12, wherein the biasing member comprises a tension spring attached to the handle proximal to an attachment to the shuttle.

14. A surgical instrument, comprising:

a handle;

an elongate implement portion;

a firing drive train, comprising;

a distal portion received for longitudinal reciprocating motion in the elongate implement portion, and

a proximal portion received in the handle for reciprocating movement between an unfired position and a fired position and coupled to the distal portion to transfer the related longitudinal reciprocating motion;

a firing trigger pivotally attached to the handle and coupled to move the proximal portion of the firing drive train from the unfired position to the fired position; and

a firing assistance mechanism, comprising;

a follower member received in the handle, proximate and aligned for movement between the unfired and fired positions of the proximal portion of the firing drive train,

a biasing member operatively configured to become preloaded by movement of the follower member from the fired position to the unfired position,

an engagement mechanism operatively configured to engage the follower member to the proximal portion of the firing drive train in response to the follower member being retracted to the unfired position and to disengaging the follower member from the proximal portion of the firing drive train in response to the engaged follower member and firing drive train being fired to the fired position, and

a brake operatively configured to maintain the proximal portion of the firing drive train retracted until the firing trigger is actuated for firing.

15. The surgical instrument of claim 14, wherein the follower member comprises a linearly moving shuttle, the biasing member comprising a linear spring attached between the handle and the linearly moving shuttle.

16. The surgical instrument of claim 15, wherein the linear spring comprises a tension spring, the linearly moving shuttle further comprising a control externally exposed on the handle.

17. The surgical instrument of claim 15, wherein the linear spring comprises a compression spring, the linearly moving shuttle further comprising a control externally exposed on the handle.

18. The surgical instrument of claim 14, wherein the proximal portion of the firing drive train comprises a rack, the follower member comprises a gear train, and the biasing member comprises a torsion coil spring biased ratchet gear attached to a rotation knob externally exposed on the handle.

19. The surgical instrument of claim 14, wherein the brake comprises a leveraged brake pad having a pivot point moved relative to the handle in response to a forward biased axle of the firing trigger moving aft in response to actuation of the firing trigger, moving the leveraged brake pad out of coupled engagement with the proximal portion of the firing drive train.

20. The surgical instrument of claim 14, wherein the brake comprises a brake arm having a rotated portion positioned to rotate into coupled engagement with the proximal portion of the firing drive train in response to a forward biased axle of the firing trigger moving aft in response to actuation of the firing actuator.

21. The surgical instrument of claim 14, wherein the follower member comprises a shuttle, the engagement mechanism further comprising a locking cam biased into engagement with the proximal portion of the firing drive train, and the handle comprising a disengaging cam positioned to move the locking cam out of engagement with the proximal portion of the firing drive train as the shuttle approaches the fired position.

22. The surgical instrument of claim 14, further comprising a spring attached between the handle and the proximal portion of the firing drive train to impart a retraction bias.

23. A surgical instrument, comprising:

a handle;

an elongate implement portion;

a firing drive train, comprising;

a distal portion received for longitudinal reciprocating motion in the elongate implement portion, and

a proximal portion received in the handle for reciprocating movement between an unfired position and a fired position and coupled to the distal portion to transfer the related longitudinal reciprocating motion;

a firing trigger pivotally attached to the handle and coupled to move the proximal portion of the firing drive train from the unfired position to the fired position; and

a retraction assistance mechanism, comprising;

a follower member received in the handle, proximate and aligned for movement between the unfired and fired positions of the proximal portion of the firing drive train,

a biasing member operatively configured to become preloaded by movement of the follower member from the unfired position to the fired position, and

an engagement mechanism operatively configured to engage the follower member to the handle in response to being moved to the fired position and to disengaging the follower member from the handle and to engage the following member to the proximal portion of the firing drive train in response to the proximal portion of the firing drive train being moved to the fired position.

24. The surgical instrument of claim 23, wherein the biasing member comprises a tension spring attached to the handle proximal to an attachment to the shuttle.