A chuck including a cylindrical body with a nose section and a tail section, the nose section having an axial bore formed therein. A sleeve is rotatably mounted about the body. Rotation of the sleeve in a closing direction moves the jaws toward a longitudinal axis of the axial bore and rotation of the sleeve in an opening direction moves the jaws away from the longitudinal axis. An O-ring is disposed adjacent the sleeve in a plane that is transverse to the longitudinal axis. A bearing has a first race adjacent the body, a second race adjacent the sleeve and bearing elements therebetween. One race defines a ratchet and the other of the first race and the second race defines a pawl biased toward the ratchet. The O-ring biases the pawl toward the ratchet and when the pawl engages the ratchet prevents the second race from rotating in the opening direction with respect to the first race.
1. A chuck for use with a manual or powered driver having a rotatable drive shaft, said chuck comprising:
a generally cylindrical body having a nose section and a tail section, said tail section being configured to rotate with said drive shaft and said nose section having an axial bore formed therein;
a plurality of jaws movably disposed with respect to said body in communication with said axial bore;
a sleeve rotatably mounted about said body in operative communication with said jaws so that rotation of said sleeve in a closing direction moves said jaws toward a longitudinal axis of said axial bore and rotation of said sleeve in an opening direction moves said jaws away from said longitudinal axis;
an O-ring disposed adjacent said sleeve, said O-ring lying in a plane that is transverse to said longitudinal axis of said axial bore; and
a bearing having a first race adjacent said body, a second race adjacent said sleeve and at least one bearing element disposed between said first race and said second race, one of said first race and said second race defining a ratchet and the other of said first race and said second race defining a pawl biased toward said ratchet;
wherein said O-ring exerts a biasing force on said pawl toward said ratchet and wherein said ratchet and said pawl are configured so that when said pawl engages said ratchet, said ratchet and pawl prevent said second race from rotating in said opening direction with respect to said first race.
2. The chuck as in claim 1 , wherein said sleeve includes a first sleeve and a second sleeve and wherein said first sleeve rotationally drives said second sleeve but is movable with respect to said second sleeve between a first position and a second position.
3. The chuck as in claim 2 , wherein said O-ring has a circular cross-section.
4. The chuck as in claim 2 , wherein said O-ring has a rectangular cross-section.
5. The chuck as in claim 2 , wherein said second sleeve further includes an annular groove configured to receive said O-ring.
6. The chuck as in claim 2 , wherein said O-ring is a material selected from a group comprising: elastomers, thermoplastics, fluoroelastomers, and perfluoroelastomers.
7. The chuck as in claim 2 , wherein said O-ring is comprised of a material selected from a group comprising: acrylonitrile-butadiene, chloroprene rubber, polyacrilic rubber, silicone rubber, buytyl rubber, styrene-butadiene, chlorosulfonated polyethelene, polysulfide rubber, fluorocarbons, polystyrene, and polyamide resins.
8. The chuck as in claim 2 , wherein a surface of said O-ring adjacent said pawl has a complimentary shape to that of said pawl.
9. The chuck as in claim 2 , wherein said O-ring comprises a material having a Shore A hardness of approximately 60 to 80.
10. The chuck as in claim 2 , wherein said first sleeve defines a cam surface disposed with respect to said pawl so that said cam surface disengages said pawl from said ratchet when said first sleeve is in said first position with respect to said second sleeve and releases said pawl to engage said ratchet when said first sleeve is in said second position with respect to said second sleeve.
11. The chuck as in claim 1 , wherein said sleeve is an annular nut having threads formed thereon in engagement with threads on said jaws so that rotation of said nut about said body moves said jaws toward or away from said axis.
12. The chuck as in claim 11 , wherein said pawl is deflectable and wherein said pawl and said ratchet are configured so that when said pawl engages said ratchet, said pawl and ratchet permit said second race to rotate in said closing direction with respect to said first race but prevent said second race from rotating in said opening direction with respect to said first race.
13. A chuck for use with a manual or powered driver having a rotatable drive shaft, said chuck comprising:
a generally cylindrical body having a nose section and a tail section, said tail section being configured to rotate with said drive shaft and said nose section having an axial bore formed therein and a plurality of passageways formed therethrough and intersecting said axial bore;
a plurality of jaws movably disposed in said passageways;
a generally cylindrical sleeve rotatably mounted about said body;
a nut rotatably mounted about said body and in operative communication with said jaws so that rotation of said nut in a closing direction moves said jaws toward a longitudinal axis of said axial bore and rotation of said nut in an opening direction moves said jaws away from said longitudinal axis; and
a bearing having a first race adjacent said body, a second race adjacent said nut and a plurality of bearing elements disposed between said first race and said second race, said first race defining a ratchet, said second race defining a deflectable first pawl biased toward said ratchet, said ratchet and said first pawl being configured so that when said first pawl engages said ratchet, said ratchet and first pawl permit said second race to rotate in said closing direction with respect to said first race but prevent said second race from rotating in said opening direction with respect to said first race, and
a biasing element disposed between said second race and said nut, wherein said biasing element is configured to bias said first pawl toward said ratchet.
14. The chuck as in claim 13 , wherein said sleeve is in operative communication with said nut so that said sleeve rotationally drives said nut but is rotatable with respect to said nut between a first rotational position and a second rotational position, and
wherein said sleeve defines a cam surface disposed with respect to said first pawl so that said cam surface disengages said first pawl from said ratchet when said sleeve is in said first position with respect to said nut and releases said first pawl to engage said ratchet when said sleeve is in said second position with respect to said nut.
15. The chuck as in claim 13 , wherein said biasing element further comprises an 0 -ring.
16. The chuck as in claim 15 , wherein said O-ring has a circular cross-section.
17. The chuck as in claim 15 , wherein said O-ring has a square cross-section.
18. The chuck as in claim 15 , wherein said nut further includes an annular groove formed in an outer surface and said O-ring is received therein.
19. The chuck as in claim 13 , said biasing element further comprising a layer of a resilient material.
20. The chuck as in claim 19 , wherein said resilient material comprises silicone room-temperature vulcanized rubber.