Hand brake for railroad car

A handbrake, including a chain connectable at one end to a railroad car brake, said brake comprising:

• (a) a chain drum by which said chain may be either taken up for effecting a brake application when rotated in one direction or let out for releasing the brake application when rotated in an opposite direction;
• (b) manually operable driving means connected to said chain drum and rotatable in one direction or an opposite direction for causing rotation of said chain drum into said one or said opposite direction, respectively, said driving means including a drive shaft having a screw-threaded portion and a pinion secured at the opposite end of said drive shaft for rotation therewith;
• and
• (c) a clutch and release mechanism cooperatively connected with said driving mechanism and operable upon rotation thereof in said one direction and upon buildup of tension on said chain during take-up thereof for effecting a brake application, to an engaged disposition in which said driving means is constrained from rotation in said opposite direction and thereby maintaining the brake application until released;
• (d) said clutch and release mechanism including ratchet means rotatable along with the driving means and cooperative with a holding pawl, upon termination of manual effort on the driving means for retaining said driving means and the brake application in a state of equilibrium, said clutch and release mechanism further including a clutch collar rotatably engaged with said pinion, an annular stationary cam member secured in fixed coaxial surrounding relation to said drive shaft adjacent to the end to which said pinion is secured, an annular movable cam disposed coaxially with and in surrounding relation to said stationary cam and being connected therewith by complementary fast pitch threads formed partly on said stationary cam and partly on said movable cam, a release lever connected to said movable cam and effective, upon rotation in one direction, for rotating said movable cam and effecting axial movement thereof via said fast pitch threads, said clutch collar having a flange formed thereon engageable by said movable cam during axial movement of the latter for operating said clutch collar to a disengaged position from said pinion, so that said pinion is disconnected from the driving mechanism and may rotate freely to effect a quick release of the brakes.