摘要:
In an instrument (1) to take the bisector of angles comprising an articulated quadrilateral (2) and a bevel (3), the engagement of the bevel (3) on the quadrilateral (2) is obtained by means of coupling pins (14a, 14b) able to be axially inserted in respective centring bushings (15a, 15b). The axial dimension of the coupling pins (14a, 14b) is as small as possible, and the reliability of the engagement is assured by the presence of one or more magnets (19, 20) which generate a force of mutual attraction between the bevel (3) and the articulated quadrilateral (2). One of the pairs of rods (6a, 6b) forming the articulated quadrilateral (2) presents a longitudinal cant to converge towards a vertex of the quadrilateral itself. A locking knob (26) operates on the articulation (13a) between the arms (12, 13) of the bevel (3) to assure mutual locking.
摘要:
The device comprises a control organ (4) slidingly mounted on a shaft (6) able to be actuated in rotation by a motor of a ventilator. The control organ (4) rigidly bears a fan (2) and is movable in contrast to a helical spring (18) by effect of an axial thrust produced by the functioning fan. The translation of the control organ (4) between a first and a second operative position causes, through a transmission kinematic mechanism (12), an air lock (2a) of the ventilator to switch from a closed condition to an open condition. A bell element (14) and an extensible protecting shroud (20) safeguard the components of the device against the entry of dust and against the action of atmospheric agents.