Brake assembly for a control rod drive

• US 5,131,510 A
• Filed: 07/30/1990
• Issued: 07/21/1992
• Est. Priority Date: 07/30/1990
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Ose, Richard A., Jamrus, Kenneth J.
• Primary Examiner(s): HALVOSA, GEORGE
• Application Number:
  US07/559,743
• Time in Patent Office: 722 Days
• Field of Search: 188/82.9, 188/82.3, 188/82.34, 188/82.4, 188/30, 188/61, 188/67, 188/171, 188/173, 74/424.8 R, 74/424.8 VA, 74/89.15, 376/232, 376/233, 376/235, 376/242
• US Class Current: 188/171
• CPC Class Codes: G21C 7/12 Means for moving control elements to desired position dropping rods in an emergency G21C9/02
• CPC Class Codes: Y02E 30/30 Nuclear fission reactors
• CPC Class Codes: Y10T 74/18696 including means to selectively transmit power [e.g., clutch, etc.]

Abstract

A brake assembly is disclosed for selectively preventing rotation of a shaft, such as a shaft used in a control rod drive for a nuclear reactor. The brake assembly includes a stationary base, a rotor disc fixedly connected to the shaft for rotation therewith, and a brake member disposed adjacent to the rotor disc. The rotor disc includes at least one rotor tooth and the brake member includes at least one braking tooth. The member is selectively positionable in a deployed position for allowing the braking tooth to contact the rotor tooth for preventing rotation of the shaft in a first direction while permitting roation in the opposite direction, and in a retracted position for allowing the rotor disc and shaft to rotate in either direction without restraint from the brake member.

Claims

1. A brake assembly for a control rod drive for selectively preventing travel of a control rod in a nuclear reactor vessel comprising:

a shaft having a longitudinal centerline axis;

means for translating said control rod upon rotation of said shaft;

means for selectively rotating said shaft in a first direction and in a second direction, opposite to said first direction;

a stationary base having a central aperture receiving said shaft;

a rotor disc fixedly connected to said shaft for rotation therewith and having at least one rotor tooth extending therefrom, said rotor tooth having a locking surface and an inclined surface extending therefrom;

a brake member disposed adjacent to said rotor disc and having at least one braking tooth having a locking surface and an inclined surface extending therefrom, said rotor tooth and said braking tooth being complementary to each other;

said brake member further including an annular base having a central aperture receiving said shaft, a first surface facing said rotor disc, and a second surface facing away from said rotor disc, and said braking tooth being disposed on said base first surface with said locking surface extending outwardly therefrom and in a radial direction relative to said shaft centerline axis, and with said inclined surface extending in a circumferential direction;

means for selectively positioning said brake member in a deployed position abutting said rotor disc for allowing said braking tooth locking surface to contact said rotor tooth locking surface for preventing rotation of said shaft in a first direction, and in a retracted position spaced away from said rotor disc for allowing said rotor disc and said shaft to rotate without restraint from said brake member;

said positioning means being effective for resiliently supporting said braking tooth for allowing said rotor tooth inclined surface to displace said braking tooth inclined surface to intermittently free said rotor tooth locking surface from said braking tooth locking surface for allowing said shaft to rotate in said second direction opposite to said first direction when said brake member is in said deployed position; and

said positioning means comprising;

a plurality of circumferentially spaced guide holes in said brake member;

a plurality of guide rods fixedly joined to said stationary base and extending parallel to said shaft centerline axis, each guide rod being slidably disposed in a respective one of said guide holes;

an electromagnet spaced from said braking member second surface and fixedly joined to said plurality of guide rods;

a plurality of springs disposed around said guide rods for providing a deploying force on said brake member for positioning said brake member in said deployed position against said rotor sic; and

wherein said guide rods are effective for preventing rotational movement of said brake member relative to said shaft centerline axis and for allowing longitudinal movement relative thereto.

2. A brake assembly according to claim 1 wherein:

said springs are compression springs disposed between said electromagnet and said brake member second surface being initially compressed for providing said deploying force against said brake member;

said electromagnet is effective for magnetically attracting said brake member for overcoming said deploying force and positioning said brake member in said retracted position when energized, and when de-energized allowing said brake member to be positioned in said deployed position by said compression springs.

3. A brake assembly according to claim 2 further comprising a plurality of said rotor teeth extending circumferentially around said rotor disc and a respective plurality of said braking teeth extending circumferentially around said brake member.