Abstract: Optical detection system having: an emitter providing a collimated light beam; a receiver receiving the collimated light beam, the receiver having: a receiver lens converging the collimated light beam along an optical axis, and a corner reflector, the corner reflector having three planar surfaces perpendicular to each other and a symmetry axis coinciding with an intersection point of the three planar surfaces and forming an equal angle with each of the planar surfaces, the corner reflector reflecting the collimated light beam about the symmetry axis. The optical axis of the receiver lens is parallel to the symmetry axis of the corner reflector.

Abstract: This invention relates to a device for fastening comprising a jaw, a screw with a diameter d and a shaft, the jaw having two parallel flanks surrounding a portion of the shaft, with the shaft having a peripheral recess in line with the screw in assembled position and with each of the flanks having an orifice that the screw passes through, it is characterised in that one of the orifices is of oblong shape. The oblong shape of the orifice makes it possible to prevent the screw from becoming “stuck” between the shaft and the orifice when the shaft is incorrectly positioned, by releasing the screw as soon as the latter enters into interference with another part or an obstacle and as such makes it possible to prevent the transmission of a torque between the two parts to be attached.