Linear actuator assembly, bionic digit and prosthetic hand

A bionic digit comprising:

• a base portion;
• an intermediate portion and an end portion;
• the intermediate portion having a longitudinal axis (A), a proximal end connected to the base portion, and a distal end;
• the bionic digit having a central plane (CP) that includes the longitudinal axis (A) of the intermediate portion;
• the end portion having a proximal end connected to the distal end of the intermediate portion, and a distal end;
• a first connector connecting the proximal end of the intermediate portion to the base portion, including a pivotal connection for allowing the intermediate portion to pivot about a first pivot axis (P1) perpendicular to the central plane (CP);
• a second connector connecting the proximal end of the end portion to the distal end of the intermediate portion, including a pivotal connection for allowing the end portion to pivot relative to the intermediate portion, about a second pivot axis (P2) perpendicular to the central plane (CP);
• a linear actuator assembly, including a drive mechanism (310) for generating a rotational force and having a proximal end and a distal end;
• a carriage mechanism (330) having a longitudinal axis (L);
• a transmission member interconnected with the carriage mechanism for transmitting the rotational force from the drive mechanism to the carriage mechanism;
• and
• a drive member coupled to the carriage mechanism;
• the carriage mechanism converting the rotational force into an axial force applied to the drive member, moving the drive member along the longitudinal axis (L) as the carriage mechanism rotates;
• the carriage mechanism (330) having a proximal end and a distal end;
• a third connector connecting the drive member to the proximal end of the end portion, including a pivotal connection between the drive member and the end portion, for allowing the end portion to pivot about a third pivot axis (P3) perpendicular to the central plane (CP), relative to the drive member;
• the intermediate portion including a housing volume, housing the linear actuator;
• wherein the linear actuator assembly further includes a first thrust bearing and a second thrust bearing;
• the first thrust bearing disposed between the proximal end of the carriage mechanism and the distal end of the drive mechanism;
• and
• the housing volume includes a seat at the distal end of the intermediate portion, for seating the second thrust bearing, the second thrust bearing disposed between the distal end of the carriage mechanism and the seat, the carriage mechanism being axially confined between the first and second thrust bearings.

A linear actuator assembly for a bionic digit that includes a housing for accommodating the linear actuator assembly;

• the linear actuator assembly comprising:
• a drive mechanism having a proximal end and a distal end, for generating a rotational force;
• a carriage mechanism having a longitudinal axis (L), a proximal end and a distal end;
• a transmission member for transmitting the rotational force from the drive mechanism to the carriage mechanism, the carriage mechanism being interconnected with the transmission member;
• and
• a drive member coupled to the carriage mechanism;
• the carriage mechanism converting the rotational force into an axial force applied to the drive member, moving the drive member along the longitudinal axis (L) as the carriage mechanism rotates;
• a first thrust bearing and
• a second thrust bearing;
• wherein
• the first thrust bearing is disposed between the proximal end of the carriage mechanism and the distal end of the drive mechanism;
• and
• the second thrust bearing can be disposed between the distal end of the carriage mechanism and a portion of the housing, the carriage mechanism being axially confined between the first and second thrust bearings.