Torque limiter

Claim 2

A torque limiter comprising, an input shaft connected to a driving unit, an output shaft connected to a driven system, a cam ring concentrically disposed relative to said input shaft and having a radial action face confronting an adjoining action face on said output shaft, a ball spline coupling connected between said input shaft and said cam ring, whereby relative axial movement of said input shaft and said cam ring is accommodated, shiftable cam means between said action faces, spring means normally preloading said cam ring to retain said cam means at a first position relative to said action faces during normal operation, and a multidisk friction brake including a spring-loaded brake backup disk axially adjacent said cam ring, whereby in the event of a jam in the driven system, relative rotation of the input and output shafts at the action faces will axially displace said cam ring to a second position for engaging the brake and providing a gradually increasing brake torque as the driving unit is stalled out for dissipating the kinetic energy of the power unit into the brake without producing high inertia torques in the drive train or the torque limiter.

Claim 3

A torque limiter as defined in claim 1 wherein said action surface on said cam ring has a plurality of V-shaped cam tracks each formed with an apical bottom portion and planar ramp portions extending away therefrom and said output shaft has a corresponding plurality to cam followers normally held at the bottom of said cam tracks but shiftable up the ramp portions thereof for the purposes set forth.

Claim 4

A torque limiter as defined in claim 2 wherein said spring means comprises Belleville type spring washers having a constant force configuration.

Claim 5

A torque limiter as defined in claim 1 wherein said action surface on said cam ring has a plurality of curved V-shaped cam tracks each formed with a apical bottom portion and curvately formed ramp portions providing an initial steep ramp angle, and said output shaft has a corresponding plurality of cam followers normally held at the bottom of said cam tracks but shiftable up the ramp portions thereof for the purposes set forth.

Claim 6

A torque limiter as defined in claim 4 wherein said spring means comprises a low force preloading spring.

Claim 7

A torque limiter as defined in claim 1 and further characterized by said cam means comprising a plurality of balls, said action surfaces comprising a cage connecting said balls and being formed with double raMped cam tracks each comprising a V-shaped track with an apical bottom portion and oppositely extending ramp portions.

Claim 8

A torque limiter as defined in claim 6 wherein said ramp portions are disposed in planar relation.

Claim 9

A torque limiter as defined in claim 6 wherein each of said ramp portions is curvately formed to provide a steep ramp angle.

Claim 10

A torque limiter comprising, input shaft means adapted to be connected to a driving unit, output shaft means adapted to be connected to a driven system, cam ring means operatively disposed between said input and output shaft means and having a low hysteresis ball spline coupling connection between said input shaft means and said cam means, said cam means including cam tracks and cam track followers normally bottomed during normal opEration but relatively movable in the event of a jam in the driven system to shift the cam means relative to the input shaft means, and a brake actuated by said cam means upon shifting, thereby to provide a gradually increasing brake torque as the driving unit is stalled out and permitting dissipation of the kinetic energy of the power unit into the brake without producing high inertia torques in the drive train or torque limiter.

Claim 11

A torque limiter comprising, input shaft means adapted to be connected to a driving unit, output shaft means adapted to be connected to a driven system, cam ring means operatively disposed between said input and output shaft means and having a low hysteresis ball spline coupling connection between said input shaft means and said cam means, said cam means including cam tracks and cam track followers normally bottomed during normal opEration but relatively movable in the event of a jam in the driven system to shift the cam means relative to the input shaft means, and a brake actuated by said cam means upon shifting, thereby to provide a gradually increasing brake torque as the driving unit is stalled out and permitting dissipation of the kinetic energy of the power unit into the brake without producing high inertia torques in the drive train or torque limiter.

Claim 12

A torque limiter comprising, an upstream torque element comprising an input shaft connected to a driving unit, a downstream torque element comprising an output shaft connected to a driven system, a cam ring concentrically disposed relative to one of said shafts and having a radial action face confronting an adjoining action face on the other of said shafts, a ball spline coupling connection between said one shaft and said cam ring, whereby relative axial movement of said one shaft and said cam ring is accommodated, shiftable cam means between said action faces, spring means normally preloading said cam ring to retain said cam means at a first position relative to said action faces during normal operation, and a multidisk friction brake including a spring-loaded brake backup disk axially adjacent said cam ring, whereby the transmitted torque will be limited in both directions of rotation and for either forward or backdriving conditions, a portion of the system energy being stored within the limiter during braking application serving to disengage the brake when the upstream torque is reversed or reduced to normal operating levels, but a reduction in downstream torque down to and including zero following lockup will not cause the unit to release.

Claim 13

A torque limiter comprising, an upstream torque element comprising an input shaft connected to a driving unit, a downstream torque element comprising an output shaft connected to a driven system, a cam ring concentrically disposed relative to one of said shafts and having a radial action face confronting an adjoining action face on the other of said shafts, a ball spline coupling connection between said one shaft and said cam ring, whereby relative axial movement of said one shaft and said cam ring is accommodated, shiftable cam means between said action faces, spring means normally preloading said cam ring to retain said cam means at a first position relative to said action faces during normal operation, and a multidisk friction brake including a spring-loaded brake backup disk axially adjacent said cam ring, whereby the transmitted torque will be limited in both directions of rotation and for either forward or backdriving conditions, a portion of the system energy being stored within the limiter during braking application serving to disengage the brake when the upstream torque is reversed or reduced to normal operating levels, but a reduction in downstream torque down to and including zero following lockup will not cause the unit to release.

Claim 14

A torque limiter as defined in claim 10 wherein one of said action faces on one of said torque elements has a plurality of V-shaped cam tracks each formed with an apical bottom portion and planar ramp portions extending away therefrom and a corresponding pluraLity of cam followers on the other torque element normally held at the bottom of said cam tracks but shiftable up the ramp portions thereof for the purposes set forth.

Claim 15

A torque limiter as defined in claim 11 wherein said spring means comprises Belleville-type spring washers having a constant force configuration.

Claim 16

A torque limiter as defined in claim 10 wherein said action face on said cam ring of one of said torque elements has a pluraLity of curved V-shaped cam tracks each formed with an apical bottom portion and curvately formed ramp portions providing an initial steep ramp angle, and said other torque element has a corresponding plurality of cam followers normally held at the bottom of said cam tracks but shiftable up the ramp portions thereof for the purposes st forth.

Claim 17

A torque limiter as defined in claim 13 wherein said spring means comprises a low force preloading spring.

Claim 18

A torque limiter as defined in claim 10 and further characterized by said cam means comprising a plurality of balls, said action surfaces comprising a cage connecting said balls and being formed with double raMped cam tracks each comprising a V-shaped track with an apical bottom portion and oppositely extending ramp portions.

Claim 19

A torque limiter as defined in claim 15 wherein said ramp portions are disposed in planar relation.

Claim 20

A torque limiter as defined in claim 15 wherein each of said ramp portions is curvately formed to provide a steep ramp angle.

Claim 21

A torque limiter comprising, upstream torque element means adapted to be connected to a driving unit, downstream torque element means adapted to be connected to a driven system, cam ring means operatively disposed between said upstream and downstream torque element means and having a low hysteresis ball spline coupling connection between said torque element means and said cam means, said cam means including cam tracks and cam track followers normally bottomed during normal operation but relativelY movable in the event of a jam in the driven system to shift the cam means relative to the torque element means, and a brake actuated by said cam means upon shifting, thereby to provide a gradually increasing brake torque as the driving unit is stalled out and permitting dissipation of the kinetic energy of the power unit into the brake without producing high inertia torques in the drive train or torque limiter, but wherein reduction in downstream torque down to and including zero following lockup will not cause the unit to release.

Claim 22

A torque limiter comprising, upstream torque element means adapted to be connected to a driving unit, downstream torque element means adapted to be connected to a driven system, cam ring means operatively disposed between said upstream and downstream torque element means and having a low hysteresis ball spline coupling connection between said torque element means and said cam means, said cam means including cam tracks and cam track followers normally bottomed during normal operation but relativelY movable in the event of a jam in the driven system to shift the cam means relative to the torque element means, and a brake actuated by said cam means upon shifting, thereby to provide a gradually increasing brake torque as the driving unit is stalled out and permitting dissipation of the kinetic energy of the power unit into the brake without producing high inertia torques in the drive train or torque limiter, but wherein reduction in downstream torque down to and including zero following lockup will not cause the unit to release.