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US 4,639,147 AGranted
Friction pivot assembly
OwnerEdward L. Schwarzinventor
Life of this patent
Estimating the term…
Abstract
A pivot assembly has a substantial amount of inherent frictional torque. A shaft has a clearance space between itself and a wall of its journal hole. A pliable tubular bushing is axially compressed within the shaft clearance space to create rotational friction between the shaft and the bearing journal. Such an assembly has diverse applications in areas such as the swivel for sailboat tiller extensions, toilet seat lid hinges, and hinged covers for electronic cabinets or other equipment.
Claims23
A rotational friction pivot comprising:
- (a) a journal member having a hole within it of preselected diameter and length;
- (b) a bracket including a cylindrical shaft having a first portion projecting at least a predetermined distance into the hole, and a second portion integral with the remainder of the bracket, said shaft and journal member being relatively rotatable with respect to each other and said shaft having a diameter within the hole establishing an annular clearance space between itself and the wall of the journal member hole;
- (c) a tubular friction bushing having first and second ends and formed of a pliable material, and having undeformed outside and inside diameters substantially that of the journal hole diameter and the shaft diameter respectively, and occupying a portion of the annular clearance space, said first and second ends of the friction bushing being adjacent the first and second portions of the shaft respectively;
- (d) first and second stop means each at least partially disposed about the shaft adjacent the first and second ends of the friction bushing, at least one of said stop means occupying a part of the annular clearance space and slidably shiftable toward the other stop means within the annular clearance space;
- and
- (e) compressing means operatively linked to the shiftable stop means for axially shifting said shiftable stop means relatively toward the other stop means and axially compressing the friction bushing within the annular clearance space, whereby the friction bushing radially expands against the journal member hole wall and the shaft surface adjacent to allow rotation with frictional slipping between the bushing and at least one of the journal member and the bracket.
3 more elements
In a method of using a pivot assembly comprising:
- (a) a journal member having a hole within it of preselected diameter and length;
- (b) a bracket including a cylindrical shaft having a first portion projecting at least a predetermined distance into the hole, and a second portion integral with the remainder of the bracket, said shaft rotatable with respect to the journal member and having a diameter within the hole establishing an annular clearance space between itself and the wall of the journal member hole;
- (c) a tubular friction bushing having first and second ends and formed of a pliable material, and having undeformed outside and inside diameters substantially that of the journal hole diameter and the shaft diameter respectively, and occupying a portion of the annular clearance space, said first and second ends of the friction bushing being adjacent the first and second portions of the shaft respectively;
- (d) first and second stop means each at least partially disposed about the shaft adjacent the first and second ends of the friction bushing, at least one of said stop means occupying a part of the annular clearance space and slidably shiftable toward the other stop means within the annular clearance space;
- and
- (e) compressing means operatively linked to the shiftable stop means for axially shifting said shiftable stop means relatively toward the other stop means and axially compressing the friction bushing within the annular clearance space, the step of adjusting the compressing means to cause the shiftable stop means to axially shift relatively toward the other stop means and cause the friction bushing to radially expand and press against the shaft and journal member hole-surfaces adjacent and allow rotation with a predetermined amount of rotational friction between the bushing and at least one of the shaft and the journal member hole wall.
3 more elements
Dependencies are inferred from the claim text.