Catch device for a roll-up door, grate, grill or the like
First Claim
Patent Images
1. A catch device for a rotatable member, comprising:
- a housing;
a shaft rotatable relative to said housing with said member;
a brake wheel mounted on said shaft in said housing and formed with a peripheral array of equispaced sawtooth formations regularly distributed around an outer circumference of said brake wheel;
a clamping ring surrounding said brake wheel and formed with a peripheral annular surface juxtaposed with a peripheral annular surface of said housing, at least one of said surfaces being eccentric with respect to an axis of rotation of said brake wheel and said shaft, whereby angular displacement of said clamping ring with said brake wheel brings said surfaces into clamping engagement, said brake wheel being rotatable in and relative to said clamping ring; and
a swingably mounted pawl normally clearing said formations to permit rotation of said brake wheel relative to said clamping ring at normal rotary speeds of said brake wheel, and entrainingly engageable with one of said sawtooth formations of said brake wheel upon development of an excessive rotary speed of said brake wheel to angularly entrain said clamping ring with said brake wheel and bring said surfaces into clamping engagement to brake said brake wheel.
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Abstract
A catch device to prevent a rapid rotation of the shaft of a roll-up door or the like has a toothed brake wheel received in an asymmetric clamping ring in a housing. A pawl on the clamping ring engages in a toothed recess of the brake ring at excessive speeds of the wheel to entrain the clamping ring and wedge the latter against the housing.
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Citations
15 Claims
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1. A catch device for a rotatable member, comprising:
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a housing; a shaft rotatable relative to said housing with said member; a brake wheel mounted on said shaft in said housing and formed with a peripheral array of equispaced sawtooth formations regularly distributed around an outer circumference of said brake wheel; a clamping ring surrounding said brake wheel and formed with a peripheral annular surface juxtaposed with a peripheral annular surface of said housing, at least one of said surfaces being eccentric with respect to an axis of rotation of said brake wheel and said shaft, whereby angular displacement of said clamping ring with said brake wheel brings said surfaces into clamping engagement, said brake wheel being rotatable in and relative to said clamping ring; and a swingably mounted pawl normally clearing said formations to permit rotation of said brake wheel relative to said clamping ring at normal rotary speeds of said brake wheel, and entrainingly engageable with one of said sawtooth formations of said brake wheel upon development of an excessive rotary speed of said brake wheel to angularly entrain said clamping ring with said brake wheel and bring said surfaces into clamping engagement to brake said brake wheel. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification