Anvil assembly with frangible retaining member

• US 9,554,802 B2
• Filed: 11/13/2013
• Issued: 01/31/2017
• Est. Priority Date: 11/13/2013
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Covidien LP (Medtronic Plc)
• Inventors: Williams, Justin, Mozdzierz, Patrick D., Joyce, Steven
• Primary Examiner(s): TRUONG, THANH K
• Assistant Examiner(s): Seif, Dariush
• Application Number:
  US14/078,766
• Publication Number:
  US 20150129635A1
• Time in Patent Office: 1,175 Days
• Field of Search: 227/177.1, 227/175.4, 227/180.1, 227/176.1, 227/19, 606/139, 606/219, 606/153
• US Class Current: 1/1
• CPC Class Codes: A61B 17/1155 Circular staplers comprising a plurality of staples
• CPC Class Codes: A61B 2090/037 with a frangible part, e.g. by reduced diameter

Abstract

An anvil assembly includes a retaining member having a body portion and a frangible portion connected to the body portion, where the frangible portion is positioned to engage a backup member and separates from the body portion during movement of the backup member from a first, proximal position to a second, distal position. The retaining member keeps the backup plate in the proximal position prior to firing of the stapling assembly, and upon separation of the frangible portion allows the backup plate to move to the distal position during firing of the stapling assembly. Proximal force on the backup plate after firing of the stapling assembly is avoided, thereby helping to ensure titling of the anvil assembly.

Claims

1. An anvil assembly comprising:

a center rod assembly; and

a head assembly including a housing, a backup member, and a retaining member, the head assembly being pivotally supported on the center rod assembly between a non-tilted position and a tilted position, wherein the backup member is movable from a first position in which a portion of the backup member is positioned to prevent pivotal movement of the head assembly from the non-tilted position to the tilted position, to a second position in which the backup member is positioned to permit pivotal movement of the head assembly in relation to the center rod assembly from the non-tilted position to the tilted position, the backup member including at least one finger, the retaining member including a body portion and a frangible portion connected to the body portion, wherein the frangible portion is positioned to engage the backup member and is configured to separate from the body portion during movement of the backup member from the first position to the second position, the body portion defining at least one cutout for accommodating the at least one finger of the backup member.

2. The anvil assembly according to claim 1, wherein the retainer member is positioned in the head assembly to prevent movement of the backup member from the first position to the second position until a predetermined force has been applied to the backup member.

3. The anvil assembly according to claim 2, wherein the predetermined force is between about ten pounds and about ninety pounds.

4. The anvil assembly according to claim 1, wherein the retainer member is positioned in the head assembly between the housing and the backup member, the retainer member further including a retaining portion formed on a first end of the body portion.

5. The anvil assembly according to claim 4, wherein the retaining portion of the retainer member is positioned adjacent an inside wall of the housing.

6. The anvil assembly of claim 4, wherein the frangible portion is supported on the body portion at a location spaced from the retaining portion.

7. The anvil assembly according to claim 1, wherein the head assembly further includes a post, the housing and the post defining an annular recess and the retainer member being positioned in the annular recess.

8. The anvil assembly of claim 1, wherein the at least one cutout in the body portion of the retainer member defines a plurality of cutouts configured to accommodate a plurality of fingers formed on the backup member.

9. The anvil assembly of claim 1, wherein the retaining member defines a weakened portion between the body portion and the frangible portion.

10. The anvil assembly of claim 9, wherein the weakened portion defines perforations.

11. The anvil assembly of claim 1, wherein the head assembly further includes a cam latch member positioned to prevent movement of the backup member from the second position to the first position.

12. The anvil assembly according to claim 11, wherein the head assembly is pivotally secured to the center rod about a pivot member, the cam latch member being pivotally mounted about the pivot member.

13. The anvil assembly according to claim 11, wherein the cam latch member is configured to maintain engagement with the backup member when the head assembly moves from the non-tilted position to the tilted position such that movement of the backup member from the second position towards the first position is prevented.

14. The anvil assembly according to claim 11, further including a plunger which is urged by a biasing member into engagement with the cam latch member to urge the cam latch member to the pivoted position.

15. The anvil assembly according to claim 11, wherein the cam latch member includes a curved surface which is configured to eliminate any gap between the cam latch member and the backup member during movement of the head assembly from the first position to the second position.

16. The anvil assembly according to claim 1, wherein the cam latch member is positioned to engage an inner periphery of the backup member when the backup member is in the first position.

17. The anvil assembly according to claim 1, wherein the backup member includes a cutting ring and a backup plate, the cutting ring being secured to a proximal face of the backup plate.

18. The anvil assembly according to claim 17, wherein the backup plate includes at least one finger positioned to engage a surface of the center rod when the backup member is in the first position to prevent pivotal movement of the head assembly in relation to the center rod.

19. The anvil assembly according to claim 18, wherein the cutting ring is formed from a softer material than the backup plate.

20. The anvil assembly according to claim 19, wherein the cutting ring is formed from polyethylene and the backup plate is formed from a metal.

21. An anvil assembly comprising:

a center rod assembly; and

a head assembly pivotally supported on the center rod assembly between an operative position and a non-operative position, the head assembly including a backup member and a retaining member supporting the backup member, wherein the backup member is movable from a first position in which a portion of the backup member is positioned to prevent pivotal movement of the head assembly from the operative position to the non-operative position to a second position in which the backup member is positioned to permit pivotal movement of the head assembly in relation to the center rod assembly from the operative position to the non-operative position, the backup member including at least one finger, the retaining member including a body portion and a frangible portion connected to the body portion, wherein the frangible portion is positioned to engage the backup member and is configured to separate from the body portion during movement of the backup member from the first position to the second position, the body portion defining at least one cutout for accommodating the at least one finger of the backup member.