Artificial hand and digit therefor

A robotic hand or a robotic claw manipulator or a prosthetic device comprising an articulated digit having plural phalanges, adjacent ends of the phalanges being connected together by a pin, a roller on each of said phalanges, a tactile sensor on the tip of said phalanges, a root of the digit being on one of the phalanges and connected by another pin to a metacarpal said pins and rollers for each digit having parallel axes, the metacarpal including a reversible motor having a shaft and a pair of fixedly mounted guide rollers having a nip;

• a first cable extending between a first point on the tip and the shaft through the nip between one side of each of the pins and a side of the rollers facing said one side of the pins, a second cable extending between a second point on the tip and the shaft over a second side of each of the pins, the first and second sides being opposite to each other, said first point, rollers, plalanges, nip and shaft being positioned and arranged so that, in response to the shaft being turned in a first direction, the first cable exerts a tensile force on the first point and a compressive force on the rollers to cause the digit to be urged toward a bent position until said tactile sensor detects the compressive force exerted on an object being grasped up to a predetermined value;
• said second point, pins, phalanges and shaft being positioned and arranged so that, in response to the shaft being turned in a second direction, the second cable exerts a tensile force on the second point and a compressive force on the pins to cause the digit to be urged toward an open position.

An artificial hand comprising a metacarpal, first and second opposed digits extending from said metacarpal, first and second reversible drive means on the metacarpal for respectively driving the first and second digits, each of said digits including:

• guide means and phalanx means between a tip and root of the digit, first and second cables, said first and second cables having a first end fixedly connected to displaced first and second points on the tip of the digit, respectively, each of said cables having a second end connected to be driven by said reversible drive means for the associated digit;
• said cables being positioned and connected to (a) said associated reversible drive means, (b) said first and second points and (c) said guide means, and (a) said phalanx means, (b) said first and second points, (c) said associated drive means and (d) said guide means being positioned and arranged so that in response to said associated drive means being activated in a first direction the first cable exerts a tensile force on said first point and a compressive force on the guide means to cause the phalanx means to be urged from a bent position toward a straight position and in response to said associated drive means being activated in a second direction the second cable exerts a tensile force on said second point and a compressive force on the guide means to cause the phalanx means to be urged away from a straight position, the compressive forces being exerted in the same direction, the tip of each digit including a tactile sensor, each of said tactile sensors including:
• a deformable membrane having a metallized region on one side thereof, electric contact means normally spaced from said metallized region, a pad having a first surface contacting the other side of said membrane, the pad being positioned on the tip and having a second surface opposite the first surface, the second surface being responsive to forces exerted on the tip so that in response to an object being grasped by the hand the sensor is responsive to forces exerted on the tip by the object, the pad being arranged so that, in response to the force exceeding a predetermined value, the membrane is deflected to cause the metallized region to contact the electric contact means and therefore instructs an on-off switch to shut off a DC motor.

A digit for robotic hand or a robotic claw manipulator or a prosthetic device comprising guide means and phalanx means between a tip and root of the digit, reversible drive means, first and second cables, said first and second cables having a first end fixedly connected to displaced first and second points on the tip of the digit, respectively, and a second end connected to be driven by said reversible drive means;

• said cables being positioned and connected to (a) said reversible drive means, (b) said first and second points and (c) said guide means, and (a) said phalanx means, (b) said first and second points, (c) said drive means and (d) said guide means being positioned and arranges so that in response to said drive means being activated in a first direction the first cable exerts a tensile force on said first point and a compressive force on the guide means to cause the phalanx means to be urged from a bent position toward a straight position and in response to said drive means being activated in a second direction the second cable exerts a tensile force on said second point and a compressive force on the guide means to cause the phalanx means to be urged away from a straight position, a tactile sensor mounted on said tip, said sensor including a deformable membrane having a metallized region on one side thereof, electric contact means normally spaced from said metallized region, a pad having a first surface contacting the other side of said membrane, the other side of the membrane being opposite said one side of the membrane, the pad having a second surface opposite the first surface, the second surface being responsive to forces exerted on the tip so that in response to an object being grasped by the hand the sensor is responsive to forces exerted on the tip by the object, the pad being arranged so that, in response to the force exceeding a predetermined value, the membrane is deflected to cause the metallized region to contact the electric contact means, and curb further bending movement of said digit toward an object being grasped.

A digit for a robotic hand or a robotic claw manipulator or a prosthetic device comprising guide means and phalanx means between a tip and root of the digit, a tactile sensor on the tip, reversible drive means, first and second cables, said first and second cables having a first end fixedly connected to displaced first and second points on the tip of the digit, respectively, and a second end connected to be driven by said reversible drive means;

• said cables being positioned and connected to (a) said reversible drive means, (b) said first and second points and (c) said guide means, and (a) said phalanx means, (b) said first and second points, (c) said drive means and (d) said guide means being positioned and arranged so that in response to said drive means being activated in a first direction the first cable exerts a tensile force on said first point and a compressive force on the guide means to cause the phalanx means to be urged from a bent position toward a straight position and in response to said drive means being activated in a second direction the second cable exerts a tensile force on said second point and a compressive force on the guide means to cause the phalanx means to be urged away from a straight position toward an object being grasped until the compressive force exerted on said object reaches a predetermined level substantially controlled by said sensor, the phalanx means including plural phalanges having aligned longitudinal axes, each of the phalanges including:
• a channel having two opposed parallel side walls connected to each other by a web, each of said side walls having an appendage extending beyond the wall, the appendage including an edge extending in a tapered fashion away from the web, the appendage being pinned to a region of the side wall of the adjacent channel in proximity to an end of the web of the adjacent channel remote from the appendage of the adjacent channel, the channels being arranged so that the webs of the adjacent channels do not contact each other.