초록 ▼

A speed change mechanism, which includes a housing enclosing a travelling nut on a rotatable screw shaft, incorporates a device for limiting torsional impact loads on the shaft. In a preferred embodiment, the torque limiting device is comprised of two groups of annular members at each end of the sha

A speed change mechanism, which includes a housing enclosing a travelling nut on a rotatable screw shaft, incorporates a device for limiting torsional impact loads on the shaft. In a preferred embodiment, the torque limiting device is comprised of two groups of annular members at each end of the shaft for frictionally absorbing impact loads created by sudden stoppage of the nut at respective ends of the shaft. Each group is comprised of at least one friction disc rotatably fixed but axially slidable with respect to the nut, and at least one torque reaction member non-rotatable within the housing against which an associated friction disc is urged via spring. Inertial loads created at ends of nut travel are thereby transferred to the housing instead of the screw shaft. In addition, the two groups of annular members cooperate with the spring to provide a pre-load shifter function for the speed change mechanism.

대표청구항 ▼

In a speed change mechanism actuable by a travelling nut on an axially extending rotatable screw shaft within a housing; an improvement comprising torque limiting means for reduction of impact loads on said shaft created by stoppage of said nut at each end of said shaft including (1) at least one fr

In a speed change mechanism actuable by a travelling nut on an axially extending rotatable screw shaft within a housing; an improvement comprising torque limiting means for reduction of impact loads on said shaft created by stoppage of said nut at each end of said shaft including (1) at least one friction disc rotatable relative to said housing, rotatably fixed, with respect to said nut, and axially slidable over said nut, (2) at least one torque reaction member axially slidable with respect to said housing but rotatably fixed relative thereto, and (3) means for urging said friction disc against said torque reaction member wherein said torque limiting means comprises a first group of two friction discs and an associated torque reaction member interjacent said discs, said first group being at one end of said shaft, said torque limiting means further comprising a second group of friction discs and an associated torque reaction member at the other end, wherein said spring is positioned axially intermediate said first and second groups of associated friction discs and reaction members.