Mandrel

Claim 2

In a releasable spool mandrel device comprising a plurality of annular clutch discs arranged to transfer torque through their outer edges to the interior cylindrical surface of a spool when axial force is applied to said discs, the improvement comprising said mandrel device comprising a spool shaft (1), bias transfer means (2), and at least one bushing (4), said spool shaft, bias transfer means and at least one bushing being coaxial and slidable relative to each other, said bushing being radially outward of at least a portion of said spool shaft, said at least one bushing (4) having an internal conical cam surface (7) inclined toward the axis and at one end means for contacting the clutch discs (3), a plurality of contact members (8) slidably disposed in said spool shaft (1) for radial movement, said contact members (8) contacting the cam surface (7) on at least one bushing (4), and means for biasing (11) said bushing against said discs through said bias transfer means and contact members such that axial movement of the bias transfer means relative to said spool shaft forces the contact members outward thus applying pressure through the at least one bushing to the clutch discs and centrifugal force moves the contact member radially outward applying further pressure to the clutch discs at high rotational speeds.

Claim 3

A spool mandrel according to claim 1 characterized by the fact that the contact members (8) are spherical or roller-shaped.

Claim 4

A spool mandreL according to claim 1 characterized by the fact that the contact members are made of a synthetic material.

Claim 5

A spool mandrel according to claim 1 characterized by the axially movable bushing (4) which abuts the annular discs being provided with a shoulder against which the annular discs (3) are braced with their inner edge.

Claim 6

In a releasable spool mandrel device comprising a plurality of annular clutch discs arranged in two separate sets (3, 3'') to transfer torque through their outer edges to the interior cylindrical surface of a spool when axial force is applied to said discs, said mandrel device comprising a spool shaft (1), bias transfer means (2), and two bushings (4, 4''), said spool shaft, bias transfer means and bushings being coaxial and slidable relative to each other, said bushings being radially outward of at least a portion of said spool shaft, each bushing (4, 4''), having an internal conical cam surface (7, 7'') inclined toward the axis and at one end means for contacting one set of clutch discs, a plurality of contact members (8) slidably disposed in said spool shaft (1) for radial movement, said contact members (8) contacting the cam surfaces (7, 7'') on the bushings (4, ''), and means for biasing (11) said bushings against said discs through said bias transfer means and contact members such that axial movement of the bias transfer means relative to said spool shaft forces the contact members outward thus applying pressure through the bushings to the two separate sets of clutch discs and centrifugal force moves the contact members radially outward applying further pressure to the clutch discs at high rotational speeds.

Claim 7

In a releasable spool mandrel device comprising a plurality of annular clutch discs arranged in two separate sets (3, 3'') to transfer torque through their outer edges to the interior cylindrical surface of a spool when axial force is applied to said discs, said mandrel device comprising a spool shaft (1), bias transfer means (2), and two bushings (4, 4''), said spool shaft, bias transfer means and bushings being coaxial and slidable relative to each other, said bushings being radially outward of at least a portion of said spool shaft, each bushing (4, 4''), having an internal conical cam surface (7, 7'') inclined toward the axis and at one end means for contacting one set of clutch discs, a plurality of contact members (8) slidably disposed in said spool shaft (1) for radial movement, said contact members (8) contacting the cam surfaces (7, 7'') on the bushings (4, ''), and means for biasing (11) said bushings against said discs through said bias transfer means and contact members such that axial movement of the bias transfer means relative to said spool shaft forces the contact members outward thus applying pressure through the bushings to the two separate sets of clutch discs and centrifugal force moves the contact members radially outward applying further pressure to the clutch discs at high rotational speeds.