Automatically resetting safety brake

In a safety brake to be connected between first and second members of a machine, said safety brake operative to stop motion between said members in response to the relative rate of motion between said members exceeding a predetermined safe speed in at least one direction of forward and reverse directions of said second member with respect to said first member, an automatically resetting actuator to control an amount of braking provided by said safety brake;

• said safety brake being the type having a fixed braking member and a movable braking member with adjacent respective frictional surfaces, said first member of said machine being connected to said fixed braking member, said second member of said machine at least while said safety brake is operative to stop movement of said second member in said forward direction being connected to said movable braking member and movable only therewith, said second member being movable in said reverse direction independent of the movement of said movable braking member, a centrifugal control assembly having an input connected to said second member of said machine, said centrifugal control assembly being movable in forward and reverse directions in response to movement of said second member with respect to said first member in forward and reverse directions respectively;
• said automatic resetting actuator comprising:
• a screw assembly including an antifrictional screw, said screw having a head portion,
• a radially extending actuating member fixed to said antifrictional screw,
• a nut assembly including a nut having a threaded portion engaging said anti-frictional screw and a non-rotatable member connected to said nut to prevent rotation of said nut,
• bearing means disposed between said head portion of said antifrictional screw and said movable braking member, compressible spring means disposed between said nut and said fixed braking member, said bearing means and said spring means being aligned to press said braking members together for increasing amounts of braking as said nut is moved inwardly along said antifrictional screw,
• said actuating member of said antifrictional screw disposed opposite said centrifugal control assembly, said centrifugal control assembly operating in response to said speed of said second member of said machine exceeding said predetermined safe speed to contact said actuating member, said actuating member upon being contacted rotating said antifrictional screw in a first direction for moving said nut inwardly for increasing braking until said movable braking member and said second member connected thereto are stopped, and
• said centrifugal control assembly being moved in said reverse direction in response to movement of said second member in said reverse direction, said actuating member thereby being permitted to be rotated in said reverse direction from force applied by said spring means to said nut, said antifrictional screw being rotated in a second direction opposite from said first direction for releasing automatically the braking that has been applied by said operation of said centrifugal control assembly.