Window treatment operating apparatus with cycloidal drive
View Patent ↗An apparatus for selectively activating a window treatment includes an input member, such as a pulley activated by a bead chain, an output member such as a sleeve activating a mandrel, a stationary guard for mounting the window treatment and a rotor. The rotor, pulley, and stationary base are coupled to form a cycloid drive, wherein rotation of the pulley causes the rotor to precess with respect to the pulley.
1. A window treatment apparatus for operating a window treatment, said apparatus comprising:
a base for supporting an end of the window treatment, said base being stationary during the operation of the window treatment;
an input member selectively activated by a control member, said input member including a pulley;
a rotor coupled to said input member;
a gear disposed between said pulley and said rotor; and
an output member connected to said window treatment for operating said window treatment when said input member is activated by the control member;
wherein said rotor and said base cooperate to form a cycloidal drive that transmits rotational motion from said input member to said output member.
2. The apparatus of claim 1 wherein the control member is operable in a first mode to rotate said pulley in a first direction and in a second mode to rotate said pulley in a second direction, and wherein said cycloidal drive is adapted to rotate said output member in first and second directions, respectively.
3. The apparatus of claim 1 wherein said cycloidal drive resists torsional forces from said output member and does not transmit the same to said input member.
4. The apparatus of claim 1 further comprising a motion transmission element transmitting rotational motion of said pulley to said rotor.
5. The apparatus of claim 4 wherein said motion transmission element is a circular rib disposed in an off-center position with respect to a rotational axis of the pulley.
6. The apparatus of claim 1 wherein said base includes projections and said rotor includes motion control elements cooperating with said projections to impart a cycloidal motion to said rotor.
7. The apparatus of claim 6 wherein said base has m projections and said rotor has n control elements where m is larger than n, wherein n and m define the mechanical advantage of the cycloidal drive.
8. The apparatus of claim 1 wherein said output member is a drum, said pulley and said drum being coaxial.
9. The apparatus of claim 1 wherein said output member is a drum, said pulley and said drum having axially offset axes of rotation.
10. A window treatment apparatus for operating a window treatment, said apparatus comprising:
a base for supporting an end of the window treatment, said base being stationary during the operation of the window treatment;
an input member selectively activated by a control member, said input member including a pulley;
a rotor coupled to said input member;
a first gear coupled to said pulley;
a second gear coupled between said first gear and said rotor; and
an output member connected to said window treatment for operating said window treatment when said input member is activated by the control member;
wherein said rotor and said base cooperate to form a cycloidal drive that transmits rotational motion from said input member to said output member.
11. A window treatment apparatus for operating a window treatment, said apparatus comprising:
a base for supporting an end of the window treatment, said guard being stationary during the operation of the window treatment;
an input member selectively activated by a control member;
a rotor coupled to said input member; and
an output member connected to said window treatment for operating said window treatment when said input member is activated by the control member;
wherein said rotor and said base cooperate to form a cycloidal drive that transmits rotational motion form said input member to said output member; and
wherein said input element is a pulley and said output member is a drum, said pulley and said drum having axially offset axes of rotation.