Patent ID: 6401565
Filing Date: 2002-06-11
Classification: B60R,Y10T

Abstract:
A self-locking telescoping device comprising:a stationary outer tube, an inner tube telescoped into the outer tube through a first end of the outer tube and supported on the outer for translation in an expansion direction and in a collapse direction, a cone-shaped ramp on the inner tube at the inboard end thereof facing an inside cylindrical wall on the outer tube, an annular end wall on the inner tube at a small diameter end of the cone-shaped ramp, a plurality of spheres between the cone-shaped ramp and the inside cylindrical wall on the outer tube cupped against the annular end wall during translation of the inner tube in the expansion direction without interfering with translation of the inner tube in the expansion direction and rolling up the cone-shaped ramp into wedging engagement between the cone-shaped ramp and the inside cylindrical wall on the outer tube at the onset of translation of the inner tube in the collapse direction thereby to render the self-locking telescoping device structurally rigid in the collapse direction, an actuator rod telescoped into the outer tube through a second end of the outer tube and into the inner tube through an inboard end of the inner tube, a drive means operable to selectively translate the actuator rod in the expansion direction and in the collapse direction, a first clutch means operable to translate the inner tube as a unit with the actuator rod in the expansion direction, a second clutch means operable to translate the inner tube as a unit with the actuator rod in the collapse direction, and a tubular retainer on the actuator rod having a plurality of slots around respective ones of the plurality of spheres each having a closed end adjacent to the corresponding one of the spheres and engageable thereon when the drive means and the second clutch means translate the actuator rod and the inner tube in the collapse direction to prevent the corresponding sphere from rolling up the cone-shaped ramp and becoming wedged between the cone-shaped ramp and the inside cylindrical wall on the outer tube.