Expansible shaft with actuator retaining member and spherical bearing surface

In an expansible shaft comprising

• an axially-extending outer housing,
• an operating rod mounted coaxially of said housing and arranged for movement axially relative to said housing,
• a core engager movable radially relative to said housing and said operating rod between an expanded position in which said core engager extends beyond the outer wall of said housing and a retracted position in which said core engager is positioned radially within said expanded position thereof, and
• an actuator mounted on said rod and arranged to cause said core engager to move towards said expanded position in response to movement of said rod axially relative to said housing,
• that improvement wherein:
• said actuator includes a bore through which said rod extends and having adjacent one end thereof a recess extending radially outward of said bore and defined at least in part by a surface inclined relative to said rod;
• and,
• a retaining member is mounted in a recess in the outer surface of said rod in position for engaging said surface of said recess of said actuator;
• whereby when said actuator is forced relative to said rod towards said retaining member, interaction between said retaining member and said surface of said recess of said actuator causes application of radially-inwardly directed force on said retaining member.

In an expansible shaft comprising

• an axially-extending outer housing,
• an operating rod mounted coaxially of said housing and arranged for movement axially relative to said housing,
• a core engager movable radially relative to said housing and said operating rod between an expanded position in which said core engager extends beyond the outer wall of said housing and a retracted position in which said core engager is positioned radially within said expanded position thereof, and
• an actuator mounted on said rod and arranged to cause said core engager to move towards said expanded position in response to movement of said rod axially relative to said housing,
• that improvement wherein:
• said actuator includes a bore through which said rod extends and having adjacent one end thereof an annular recess surrounding said bore and defining a generally inwardly facing annular surface;
• a retaining member is mounted in a circumferential groove in the outer surface of said rod in position for engaging said surface of said recess of said actuator;
• and,
• when said actuator is forced relative to said rod into engagement with said retaining member
• (i) said retaining member fits at least partially within said annular recess of said actuator with said annular surface of said recess generally circumfentially surrounding the portion of said retaining member within said recess and
• (ii) said annular surface of said recess limits potential movement of said retaining member in a direction radially outwardly relative to said rod to a distance less than the difference between the inner diameter of said retaining member and the diameter of said rod.