End-effector jaw closure transmission systems for remote access tools

A device having a jaw assembly actuated by a transmission cable having a finite stiffness in a transmission direction, the device comprising:

• an elongate, flexible transmission guide, wherein the transmission cable is routed through the elongate, flexible transmission guide;
• an input assembly at a proximal end of the elongate, flexible transmission guide, the input assembly comprising an input body and an input member, the input member coupled to the proximal end of the transmission cable, wherein the input member has an input stroke relative to the input body, further wherein the input stroke includes a first part that corresponds to a displacement of 30% to 70% of the full displacement of the input member and a second part that corresponds to the remaining displacement of the input member;
• an intermediate transmission coupled to the transmission cable and configured to provide a first mechanical advantage during the first part of the input stroke and a second mechanical advantage that is greater than the first mechanical advantage during the second part of the input stroke;
• and
• wherein the jaw assembly is distal to the elongate, flexible transmission guide, the jaw assembly having a first jaw, a second jaw, and a jaw input coupling the transmission cable to the second jaw or the first and second jaw, wherein the jaw assembly has an open configuration when the first and second jaws are fully open relative to each other and a closed configuration when the first and second jaws are closed;
• further wherein the displacement of the input member relative to the input body corresponding to the first part of the input stroke actuates the proximal end of the transmission cable which in turn actuates the jaw input, which in turn closes the first and second jaws until the first and second jaws reach a stop, and thereafter the displacement of the input member relative to the input body corresponding to the second part of the input stroke stretches the transmission cable, wherein the resulting tension in the transmission cable is converted by the jaw assembly to an increasing force between the first and second jaws.

A method of operating a medical device to close a jaw assembly of the medical device, wherein the medical device comprises an elongate transmission guide, a transmission cable within the transmission guide, and an input assembly at the proximal end of the transmission cable, the input assembly having an input member coupled to the transmission cable, wherein the transmission cable is coupled to an input of the jaw assembly, wherein the jaw assembly is distal to the elongate transmission guide, the method comprising:

• actuating the input member to apply tension to the transmission cable during a first part of an input stroke of the input assembly to close a first and second jaw of the jaw assembly from an open configuration until the first and second jaws reach a stop;
• continuing to actuate the input member during a second part of the input stroke after the first and second jaws have reached the stop and stretching the transmission cable;
• wherein the input stroke consists of a displacement of the input member, and further wherein the input member transitions from the first part of the input stroke to the second part of the input stroke when the input member is between 30% and 70% displaced;
• and
• applying a first mechanical advantage to the first and second jaws during the first part of the input stroke and applying a second mechanical advantage to the first and second jaws that is greater than the first mechanical advantage during the second part of the input stroke.