Apparatus for cocking a biopsy device
A biopsy device includes a housing, a stylet carriage having a strike, a cannula carriage having a strike, and a cocking element comprising a catch carried by a resilient shaft that extends along an operational axis of the biopsy device. To arm the biopsy device, the cocking element is moved in a first arming stroke such that the catch engages the strike on the cannula carriage to deflect the resilient shaft from the operational axis such that the catch clears the strike on the stylet.
1. A biopsy device for the percutaneous removal of a specimen from a tissue mass, the biopsy device comprising:
a housing defining an interior having an operational axis;
a cannula carriage provided in the housing for reciprocal movement between an armed position and a fired position within the interior and having a cannula strike laterally offset from the operational axis in a first lateral direction;
a stylet carriage provided in the housing for reciprocal movement between an armed position and a fired position within the interior and having a stylet strike laterally offset from the operational axis in a second lateral direction opposite the first lateral direction and proximal of the cannula strike when the cannula carriage and the stylet carriage are in the fired position; and
a cocking element slidably mounted to the housing for movement between a first position and a second position to define an arming stroke, and having a catch integrally formed with a resilient shaft extending along the operational axis;
wherein the catch, when the stylet and cannula carriages are in the fired positions, is configured to engage the cannula strike, upon a first arming stroke, to deflect the resilient shaft from the operational axis in the first lateral direction such that the catch clears the stylet strike and moves the cannula carriage to the armed position.
2. The biopsy device according to claim 1 wherein the catch is configured to engage the stylet strike, upon a second arming stroke, to deflect the resilient shaft from the operational axis in the second lateral direction to move the stylet carriage to the armed position when the cannula carriage is in the armed position.
3. The biopsy device according to claim 2 , wherein the catch comprises an arrow-shaped lug having a first angled arm configured to engage the cannula strike during the first arming stroke and a second angled arm configured to engage the stylet strike during the second arming stroke.
4. The biopsy device according to claim 3 wherein the cannula strike comprises an angled distal face configured to engage the first angled arm during the first arming stroke to deflect the resilient shaft from the operational axis.
5. The biopsy device according to claim 4 wherein the stylet strike comprises an angled distal face that is proximal the distal face of the cannula strike when the cannula carriage is in the fired position and is configured to engage the second angled arm during the second arming stroke.
6. The biopsy device according to claim 2 and further comprising an alignment device configured to maintain the resilient shaft in alignment with the operational axis.
7. The biopsy device according to claim 6 wherein the alignment device comprises a track for guiding the movement of the catch during the first and second arming strokes.
8. The biopsy device according to claim 7 wherein the track is formed in the stylet carriage.
9. The biopsy device according to claim 7 wherein the catch comprises a pin configured to ride within the track.
10. The biopsy device according to claim 9 wherein the track is configured to guide the catch toward the stylet strike during the second arming stroke.
11. The biopsy device according to claim 1 further comprising: a stylet carried by the stylet carriage; and
a cannula carried by the cannula carriage and defining a lumen for receiving the stylet.
12. The biopsy device according to claim 1 wherein the cannula carriage is laterally offset from the operational axis in the first lateral direction and the stylet carriage is laterally offset from the operational axis in the second lateral direction.
13. The biopsy device according to claim 1 wherein the cocking element further comprises a pull coupled to the resilient shaft opposite the catch and located on the exterior of the housing, wherein the pull is configured to be grasped by a user and pulled proximally to move the cocking element from the first position to the second position.
14. The biopsy device according to claim 13 wherein the housing comprises an enlarged bearing portion to allow a user's fingers to securely grip the housing while the pull is pulled proximally.
15. The biopsy device according to claim 2 further comprising an actuator operably coupled to the stylet carriage and the cannula carriage to sequentially move each of the stylet carriage and cannula carriage from the armed position to the fired position.
16. The biopsy device according to claim 15 , wherein the actuator further comprises a stylet retainer configured to engage a stylet stop formed on the stylet carriage to releasably retain the stylet carriage in the armed position and a cannula retainer configured to engage a cannula stop formed on the cannula carriage to releasably retain the cannula carriage in the armed position.
17. The biopsy device according to claim 16 wherein the cannula retainer is configured to be moved into engagement with the cannula stop during the first arming stroke and the stylet retainer is configured to be moved into engagement with the stylet stop during the second arming stroke.
18. The biopsy device according to claim 17 wherein the retainers comprise levers which are pivotably mounted within the housing.
19. The biopsy device according to claim 17 wherein the actuator further comprises:
a first button mounted to the housing and operably coupled to the stylet retainer; and
a second button mounted to the housing and operably coupled to both the stylet retainer and the cannula retainer;
wherein the first button is configured to release the stylet retainer from the stylet stop when pressed and the second button is configured to release the cannula retainer from the cannula stop when pressed.
20. The biopsy device according to claim 19 wherein the second button is configured to release the stylet retainer from the stylet stop prior to releasing the cannula retainer from the cannula stop when the second button is pressed before the first button is pressed.
21. The biopsy device according to claim 1 further comprising a delay arm in the housing configured to delay the movement of the cannula carriage when moving the cannula carriage from the armed position to the fired position.