Forceps drive systems

A medical device for operating an end effector, the medical device comprising:

• a housing that forms at least a portion of a handle;
• a drive shaft that is moveable relative to the housing to actuate the end effector;
• a drive body operably coupled to the drive shaft, wherein the drive body is configured to translate with respect to the housing, the drive body having a proximal collar and a distal collar;
• and
• a drive link pivotably coupled to the housing at a first end and pivotably coupled to an actuator at a second end, the drive link actuatable by the actuator,
• wherein the drive link is actuatable to translate the drive shaft with respect to the housing, and wherein the drive link includes a proximal cam surface and a distal cam surface opposite the proximal cam surface,
• wherein the proximal cam surface is configured to interface with the proximal collar when the drive link displaces proximally to translate the drive body in a proximal direction,
• wherein the distal cam surface is configured to interface with the distal collar when the drive link displaces distally to translate the drive shaft in a distal direction, and
• wherein the proximal cam surface is defined by a first curvature defined by a first radius with a first center point and the distal cam surface is defined by a second curvature defined by a second radius with a second center point.

A medical device for operating an end effector, the medical device comprising:

• a housing that forms at least a portion of a handle;
• a drive shaft that is moveable relative to the housing via a pair of opposing surfaces to actuate the end effector;
• and
• a drive link pivotably coupled to the housing at a first end and pivotably coupled to an actuator at a second end, wherein the drive link is pivotable about the first end by the actuator to engage one or more of the pair of opposing surfaces to translate the drive shaft with respect to the housing,
• wherein:
• the pair of opposing surfaces comprises a distal-facing proximal face and a proximal-facing distal face,
• the drive link includes a proximal cam surface configured to engage the distal-facing proximal face and a distal cam surface configured to engage the proximal-facing distal face, and
• the proximal cam surface is defined by a first curvature defined by a first radius with a first center point and the distal cam surface is defined by a second curvature defined by a second radius with a second center point.