Emergency overspeed brake

An overspeed safety brake for a rotary shaft rotatable relative to a stationary base comprising

• a member mountable on the stationary base in proximity of the shaft;
• at least one stop integrally mounted to a portion of said member and extending radially inwardly toward the shaft;
• a hub integrally mountable on the shaft axially spaced from said member for rotation with the shaft;
• a lug operatively connected to said hub;
• at least one pawl;
• means for mounting said pawl for outwardly radial movement of the entire pawl in response to centrifugal force such that said pawl can move radially outwardly interposed between said stop and said lug and engage said stop and said lug and thereby apply a rotation stopping force that is transmitted from said stop through said pawl to said lug and hence to said hub and the shaft;
• and
• means for preventing any outwardly radial movement of said pawl until a predetermined shaft rotational speed is obtained and then for releasing said pawl.

An overspeed safety brake for a rotary shaft rotatable relative to a stationary base comprising:

• a member mountable on the stationary base in proximity of the shaft;
• at least one stop integrally mounted to a portion of said member and extending radially inwardly toward the shaft;
• a hub integrally mountable on the shaft axially spaced from said member for rotation with the shaft;
• at least one lug generally rotatable with the shaft and spaced radially from said stop and extending axially to an overlapping relationship with said stop;
• means for operatively connecting said lug to said hub;
• at least one pawl angularly spaced from said lug;
• and
• means for mounting said pawl for radial movement of at least one end thereof in response to centrifugal force such that said pawl is interposed between said stop and said lug for stopping engagement therewith at a predetermined shaft angular velocity, thereby stopping the rotation of said hub and hence of said shaft.

An overspeed safety brake for a shaft rotating at relatively low speeds and comprising:

• an annular member mountable on a stationary base having a central bore through which the shaft can extend and an annular outer ring concentric and integral with said inner ring;
• first and second radially inwardly extending stops integrally mounted on said outer ring spaced apart on either side of said central bore;
• a hub having a bore therethrough for being mounted on said shaft for rotation therewith;
• first and second yokes mountable on said hub and generally rotatable with the shaft;
• at least two lugs operatively connected to said hub and generally rotatable with the shaft;
• first and second elongate pawls mounted on opposite sides of said hub bore and having first and second opposing ends;
• a first pair of connecting members for connecting said first and second ends of said first pawl to said first and second yokes, respectively, and
• a second pair of connecting members for connecting said first and second ends of said second pawl to said second and first yokes, respectively, thereby balancing gravity effects when brake is installed with shaft horizontal;
• and
• means for releasably retaining said first and second pawls in a radially inward position during the rotation thereof until the centrifugal force reaches a predetermined level, thereupon permitting said pawls to travel radially outwardly in response to the centrifugal force and to be interposed between said stop and said lug in stopping engagement therewith;
• and thereby stopping the rotation of said hub and hence said shaft.