Patent ID: 7278185

Claim:
A restricting device for a closure including a vent hingedly connected to a frame, the restricting device being adapted to act between the vent and the frame, and comprising a mounting plate, a support plate having an aperture therethrough, an arm, and means for releasably interengaging the arm and the mounting plate, wherein, in use, when the mounting plate and the arm are interengaged, the closure can only be opened a predetermined distance, the means for releasably interengaging the arm and the mounting plate comprising: a resilient strip having two legs positioned between the mounting plate and the support plate; and a locking pin connected at a first end to the arm and comprising a head at a second end opposed to the first end and a neck between the first and the second ends having a diameter less than a diameter of the head, the head and neck dimensioned to permit a snap fit between the resilient strip legs, the mounting plate having an aperture for admitting a key having an eccentric head therethrough and a protrusion extending from a distal end thereof, the key head having a first and a second cross-sectional dimension, the second cross-sectional dimension greater than the first cross-sectional dimension and greater than a separation between the legs, the mounting plate aperture positioned and dimensioned for admitting the key head between the legs with the key head having the first cross-sectional dimension aligned with the legs, a turning of the key operative to force the legs apart to a sufficient width to release the locking pin from engagement with the resilient strip, the key head protrusion extending into the support plate aperture, the support plate aperture comprising a feature for preventing the key head protrusion, and thereby the key, to turn beyond a predetermined angle.