Replaceable surgical scissor blades for surgical instruments

1 . A surgical tool, comprising:

a drive housing;

an elongate shaft extending distally from the drive housing;

a wrist arranged at a distal end of the shaft and including a distal clevis with first and second distally-extending arms; and

an end effector operatively coupled to the wrist and including:

a first blade holder rotatably mounted to the first arm at a first axle;

a second blade holder rotatably mounted to the second arm at a second axle independent of the first axle, wherein the first and second blade holder each include:

an open-ended blade channel sized to receive a shank of a laterally adjacent blade of first and second blades; and

an open-ended pin slot defined within the blade channel and sized to receive a portion of a center pin;

the first blade releasably coupled to the first blade holder with a first securing device, wherein the first securing device provides a first latching feature arranged to engage a first projected shoulder provided in the pin slot of the first blade holder; and

the second blade rotatably coupled to the first blade at the center pin and releasably coupled to the second blade holder with a second securing device, wherein the second securing device provides a second latching feature arranged to engage a second projected shoulder provided in the pin slot of the second blade holder,

wherein disengaging the first and second securing devices from the first and second blade holders allows the first and second blades to be separated from the first and second blade holders.

2 . The surgical tool of claim 1 , wherein the first and second axles and the center pin are coaxially aligned along a pivot axis, and wherein the first and second blade holders and the first and second blades are rotatable about the pivot axis.

3 . The surgical tool of claim 1 , wherein each securing device comprises a leaf spring received within a recess defined in a shank of a corresponding one of the first and second blades, and each latching feature is spring biased to naturally project laterally outward from the shank and away from the recess to engage a corresponding one of the first and second projected shoulders.

4 . The surgical tool of claim 1 , wherein each blade holder defines a latch aperture through which the first and second latching features are engageable to disengage the first and second latching features from the first and second projected shoulders, respectively.

5 . A method, comprising:

providing a surgical tool that includes:

an elongate shaft extending distally from a drive housing;

a wrist arranged at a distal end of the shaft and including first and second distally-extending arms; and

an end effector operatively coupled to the wrist and including first and second blade holders rotatably mounted to the first and second arms at first and second axles, respectively,

wherein the first and second blade holder each include an open-ended blade channel sized to receive a shank of a laterally adjacent blade of first and second blades, and an open-ended pin slot defined within the blade channel and sized to receive a portion of a center pin,

wherein the first and second axles are independent of each other,

wherein the first blade is releasably coupled to the first blade holder with a first securing device, and the second blade is rotatably coupled to the first blade at the center pin and releasably coupled to the second blade holder with a second securing device,

wherein the first securing device provides a first latching feature arranged to engage a first projected shoulder provided in the pin slot of the first blade holder,

wherein the second securing device provides a second latching feature arranged to engage a second projected shoulder provided in the pin slot of the second blade holder;

disengaging the first and second securing devices from the first and second blade holders; and

separating the first and second blades from the first and second blade holders.

6 . The method of claim 5 , wherein disengaging the first and second securing devices from the first and second blade holders comprises:

laterally engaging a first latching feature of the first securing device through a first latch aperture defined in the first blade holder;

laterally engaging the second latching feature through a second latch aperture defined in the second blade holder;

forcing the first latching feature laterally inward and thereby disengaging the first latching feature from the first projected shoulder; and

forcing the second latching feature laterally inward and thereby disengaging the second latching feature from the second projected shoulder.

7 . The method tool of claim 5 , wherein disengaging the first and second securing devices from the first and second blade holders comprises:

inserting the end effector into an insertion aperture defined in a disassembly cassette, and advancing the end effector into an interior of the disassembly cassette;

depressing a first detachment button provided on a first side of the disassembly cassette and thereby disengaging the first latching feature of the first securing device from the first projected shoulder;

depressing a second detachment button provided on a second side of the disassembly cassette and thereby disengaging the second latching feature of the second securing device from the second projected shoulder; and

withdrawing the end effector from the disassembly cassette while the first and second blades remain within the interior.

8 . The method of claim 7 , wherein the disassembly cassette includes first and second insertion lockout members arranged within the interior and each defining an aperture sized to receive a disengagement post provided by a corresponding one of the first and second detachment buttons, the method further comprising:

engaging the first and second lockout members as the end effector advances into the interior of the disassembly cassette;

moving, with the end effector, each insertion lockout member from a blocking position, where the aperture is misaligned with the disengagement post, to an aligned position, where the aperture aligns with the disengagement post;

depressing the first detachment button and thereby advancing the disengagement post of the first detachment button through the aperture of the first insertion lockout member and engaging the first latching feature; and

depressing the second detachment button and thereby advancing the disengagement post of the second detachment button through the aperture of the second insertion lockout member and engaging the second latching feature.

9 . The method of claim 7 , further comprising:

receiving a first blade retention feature provided in the interior within a first disassembly detent defined on the first blade;

receiving a second blade retention feature provided in the interior within a second disassembly detent defined on the second blade; and

retaining the first and second blades within the interior with the first and second retention features as the end effector withdraws from the disassembly cassette.

10 . The method of claim 5 , further comprising:

inserting the end effector without the first and second blades into an insertion aperture defined in an assembly cassette, and advancing the end effector into an interior of the assembly cassette, wherein new first and second blades are pre-installed within the assembly cassette;

attaching the new first and second blades to the first and second blade holders, respectively, as the end effector advances into the interior; and

withdrawing the end effector from the assembly cassette with the new first and second blades attached to the first and second blade holders, respectively.

11 . The method of claim 10 , wherein first and second blade camming features are provided within the interior of the assembly cassette, and wherein inserting the end effector without the first and second blades into the insertion aperture is preceded by:

securing the new first blade within the interior by receiving the first blade camming feature within a first assembly detent defined on the new first blade; and

securing the new second blade within the interior by receiving the second blade camming feature within a second assembly detent defined on the new second blade.

12 . The method of claim 10 , wherein attaching the new first and second blades to the first and second blade holders, respectively, comprises:

engaging a new first latching feature coupled to the new first blade against the first projected shoulder provided on the first blade holder, and thereby securing the new first blade to the first blade holder; and

engaging a new second latching feature coupled to the new second blade against the second projected shoulder provided on the second blade holder, and thereby securing the new second blade to the second blade holder.

13 . The method of claim 12 , further comprising:

receiving a first shank of the new first blade in the blade channel of the first blade holder;

receiving a second shank of the new second blade in the blade channel of the second blade holder; and

receiving portions of the center pin in the pin slot of the first and second blade holders.

14 . An end effector for a surgical tool, comprising:

a first blade holder rotatably mountable to a first arm of a distal clevis at a first axle;

a second blade holder rotatably mountable to a second arm of the distal clevis at a second axle independent of the first axle, wherein the first and second blade holder each include:

an open-ended blade channel sized to receive a shank of a laterally adjacent blade of first and second blades; and

an open-ended pin slot defined within the blade channel and sized to receive a portion of a center pin;

the first blade releasably coupled to the first blade holder with a first securing device, wherein the first securing device provides a first latching feature arranged to engage a first projected shoulder provided in the pin slot of the first blade holder; and

the second blade rotatably coupled to the first blade at the center pin independent of the first and second axles and releasably coupled to the second blade holder with a second securing device, wherein the second securing device provides a second latching feature arranged to engage a second projected shoulder provided in the pin slot of the second blade holder,

wherein the first and second axles and the center pin are coaxially aligned along a pivot axis, and the first and second blade holders and the first and second blades are rotatable about the pivot axis, and

wherein disengaging the first and second securing devices from the first and second blade holders allows the first and second blades to be separated from the first and second blade holders.

15 . The end effector of claim 14 , wherein each securing device comprises a leaf spring received within a recess defined in the shank of the laterally adjacent blade of the first and second blades, and each latching feature is spring biased to naturally project laterally outward from the shank and away from the recess to engage a corresponding one of the first and second projected shoulders.

16 . The end effector of claim 14 , wherein each blade holder defines a latch aperture through which the first and second latching features are engageable to disengage the first and second latching feature from the first and second projected shoulders, respectively.

17 . An end effector for a surgical tool, comprising:

a first blade holder rotatably mountable to a first arm of a distal clevis at a first axle;

a second blade holder rotatably mountable to a second arm of the distal clevis at a second axle independent of the first axle;

a first blade releasably coupled to the first blade holder with a first securing device; and

a second blade rotatably coupled to the first blade at a center pin independent of the first and second axles and releasably coupled to the second blade holder with a second securing device,

wherein the first and second axles and the center pin are coaxially aligned along a pivot axis, and the first and second blade holders and the first and second blades are rotatable about the pivot axis,

wherein the first securing device provides a first latching feature arranged to engage a first projected shoulder provided on the first blade holder, and the second securing device provides a second latching feature arranged to engage a second projected shoulder provided on the second blade holder,

wherein each securing device comprises a leaf spring received within a recess defined in a shank of a laterally adjacent blade of the first and second blades, and each latching feature is spring biased to naturally project laterally outward from the shank and away from the recess to engage a corresponding one of the first and second projected shoulders, and

wherein disengaging the first and second securing devices from the first and second blade holders allows the first and second blades to be separated from the first and second blade holders.