Friction drive transmission
AssigneeWedgtrac Corporation
InventorsBertel S. Nelson, Woodrow D. Nelson
Life of this patent
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Abstract
A rotary motion transmitting device including traction rollers for transmitting motion in either direction from an input shaft to an output shaft. One shaft carries an internal traction ring and the other shaft, whose axis is parallel to, but slightly spaced from, the traction ring shaft, extends into the traction ring and carries an inner roller to form a varying annular space. Three intermediate traction rollers are angularly disposed within this annular space and are urged into firm Hertzian contact with both the traction ring and the inner roller by means of the torque transmitted through the device. The five traction rollers have a sum of degrees of freedom of movement in a plane perpendicular to the axes of the rollers equal to 8, 9 or 10.
Claims18
A rotary motion transmission device, operable in either direction of rotation with a fixed transmission ratio, comprising input and output shafts having spaced parallel axes of rotation, a ring roller having a cylindrical internal traction surface carried by one of said shafts, an inner roller having a cylindrical external traction surface carried by the other of said shafts, the traction surface of said inner roller extending into said ring roller such that an annular path of varying width is formed between the ring roller and said inner roller, three intermediate traction rollers positioned within said annular path in angularly spaced relation to each other, said five rollers having parallel axes of rotation, each intermediate roller contacting simultaneously said ring roller traction surface and said inner roller traction surface, one of said intermediate rollers being a wedging roller having 2.degree. of freedom of movement in a plane perpendicular to the axis of the rollers, the two remaining intermediate rollers being reaction rollers each having at least 1.degree. of freedom of movement in said plane, said ring roller having 2.degree. of freedom of movement in said plane, the sum of the degrees of freedom of movement in said plane for all five said rollers being at least eight and not more than 10 when notional lines connect the centers of the said ring roller and said inner roller with the center of said wedging roller, said notional lines forming an angle which does not exceed twice the angle whose tangent is equal to the coefficient of traction.
Dependencies are inferred from the claim text.