(57) Disclosed is apparatus for sensing the end of travel of curtain drawn by a cord and
associated electric motor (103). The apparatus consists of an assembly (100), including
the motor (103), in which a sensing member (3;200) is mounted for rotation about a
hollow boss (120) carried on a face (101) of the assembly, and through which the motor
drive shaft (2) extends. A cord drive pulley (4) is carried at the end of the drive
shaft (2) adjacent the sensing means (3;200); a beam member (20;210) is pivotally
mounted (21;222) on the sensing means (3;200) above the drive pulley (4) and carries
guide pulleys (22, 23) rotatably mounted at each end thereof such that they are spaced
apart from the drive pulley (4). The curtain cord (31, 32) is passed between the guide
pulleys (22, 23) and looped about the drive pulley (4). When the curtain reaches the
end of its travel tension in the end of one cord run (31, 32) increases causing the
beam (20; 210) to pivot and bring one of the guide pulleys (22, 23) adjacent the drive
pulley (4) such that the cord run (31, 32) is pinched between the said guide (22,
23) pulley and the drive pulley (4) whereby the sensing (3; 200) means is caused to
rotate about the hollow boss (120) against resilient means (10; 232, 233). A switch
(8) in the motor drive circuit and positioned in the assembly is associated with means
(5, 6, 7;) secured to the sensing member (3,200) and is opened in response to a predetermined
degree of rotation of the sensing member (3,200) to stop the motor drive (103). The
resilient means (10; 232, 233) acting against the sensing means (3; 200) control the
degree of rotation of the sensing means (3;200), and further means (14, 15; 234) are
provided to act on the resilient means (10,232,233) and vary the force acting between
the said means (10,232,233) and the plate (3) whereby the tension in a cord run (31,
32) required to cause rotational movement of the sensing means (3; 200) can also be
varied.
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