| 主权项 |
1. An anti-drop transmission device for a service door (1) with a flexible curtain (5), said anti-drop transmission device (6) comprising:
a drive shaft (4) that holds the flexible curtain (5) of the service door (1), wherein, the drive shaft (4) is located on an upper part of a first jamb (2) of opposite vertical first and second jambs (2, 3), the drive shaft (4) includes an output shaft (9) that extends through the first jamb from an inner side to an outer side of the first jamb (2), and when moving between an open position and a closed position, the flexible curtain is rolled around the drive shaft; a motor (7) fixed on the first jamb (2), the motor having an output axle (10) that extends through the first jamb from the inner side to the outer side of the first jamb (2), the output axle (10) having an axis of rotation offset and parallel with respect to an axis of rotation of the drive shaft (4); and an anti-drop protection device (8) connecting the motor (7) to the drive shaft (4), the anti-drop protection device (8) that provides speed reductions between the motor and the drive shaft, the anti-drop protection device (8) comprising i) a first pulley (11) integrally connected to the output axle (10) of the motor (7), ii) a second pulley (13) integrally connected to the output shaft (9) of the drive shaft (4), iii) a belt (12) connecting said first and second pulleys (13, 11), the first and second pulleys together with the belt (12) forming a kinematic chain, and iv) a variable-speed drive which controls a speed of the motor (7), v) a brake unit (15) that provides parking braking when the drive shaft is stopped, and dynamic emergency braking in an event of the kinematic chain formed by the first and second pulleys (11, 13) and the belt (12) breaking, wherein activation of the brake unit (15) blocks the rotation of the drive shaft (4), and vi) a tension sensor (16) checking a tension of the belt (12) connecting the first and second pulleys (11, 13) to thereby detect the event of the kinematic chain formed by the first and second pulleys (11, 13) and the belt (12) breaking, the tension sensor (16) providing an anti-drop function activating the brake unit (15) to prevent rotation of the drive shaft (4) upon detecting the event of the kinematic chain formed by the first and second pulleys (11, 13) and the belt (12) breaking, wherein the anti-drop protection device (8) controls the motor (7) to drive the drive shaft (4), via the belt (12), between the open and closed positions and blocks the accidental dropping-down of the flexible apron (5) by preventing rotation of the drive shaft (4). |
