Intruder resistant roller shutter safety mechanism - has stop faces both ends of locking recess concentric to ratchet wheel

摘要

Safety mechanism prevents unwanted rolling up of a roller shutter, or similar closure filling which is rolled on a spindle. It incorporates a ratchet wheel joined to the shaft, with peripheral recesses for locking units; the fixed housing for this has an ID barely exceeding the size of the wheel, and has a top inwards opening recess shallower than the wheel. The locking recess is set concentrically to the periphery of the ratchet wheel (1), and is fitted with stop faces (6, 7), working in conjunction with the locking units, at both ends in the running direction. There may be a permanent magnet (8) above the locking recess, of shorter length than this, insertable into the housing from outside. The housing and/or ratchet wheel may be made of plastics. The ratchet wheel can run both ways, with the lock effective both ways, so that the mechanism can be installed on either side of the shutter.