Cordless window covering
First Claim
1. A window covering comprising:
- a ballast element;
an adjustable light blocking element connected to the ballast element;
at least one suspension cord associated with the light blocking element; and
a suspension mechanism connected to the suspension cord to adjust the light blocking element, the suspension mechanism having;
a first rotary drum adapted to wind and unwind the suspension cord;
a spring having a first end, and a second end mounted on an axle, the first end being rotatable with respect to the second end; and
a transmission system operatively connecting the first rotary drum and at least one end of the spring to transmit a rotating movement at a differential rotation rate between the first rotary drum and the one end of the spring such that the first rotary drum rotates at a faster rate than an effective rotational displacement of the spring.
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Abstract
A cordless window covering having a differential suspension mechanism. The suspension mechanism is composed of a first rotary drum for winding and unwinding the suspension cord of a window covering and a second rotary drum housing a spring with one end connected to the second rotary drum and the other end of the spring connected to an axle. Rotation of the first rotary drum and at least one end of the spring are linked by a transmission system. In operation, the transmission system creates a differential rotation rate between the first rotary drum and the relative rotation rate of the two ends of the spring. In this manner, a greater length of cord can be deployed for with a shorter length of spring extension.
70 Citations
30 Claims
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1. A window covering comprising:
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a ballast element;
an adjustable light blocking element connected to the ballast element;
at least one suspension cord associated with the light blocking element; and
a suspension mechanism connected to the suspension cord to adjust the light blocking element, the suspension mechanism having;
a first rotary drum adapted to wind and unwind the suspension cord;
a spring having a first end, and a second end mounted on an axle, the first end being rotatable with respect to the second end; and
a transmission system operatively connecting the first rotary drum and at least one end of the spring to transmit a rotating movement at a differential rotation rate between the first rotary drum and the one end of the spring such that the first rotary drum rotates at a faster rate than an effective rotational displacement of the spring. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A window covering comprising:
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a ballast element;
at least one light blocking element connected to the ballast element;
a suspension cord associated with the light blocking element;
a suspension mechanism engagingly connected to the suspension cord, the suspension mechanism comprising;
a spring having a first end and a second end;
a rotary winding drum for winding and unwinding the suspension cord;
a rotary loading drum connected to the first end of the spring and driven in rotation by a rotation of the rotary winding drum; and
a rotary axle connected to the second end of the spring and rotating at a different rate relative to the rotary loading drum such that the rotary winding drum has a rotation rate greater than an effective rotational displacement of the spring. - View Dependent Claims (13, 14, 15, 16)
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17. A window covering comprising:
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a ballast element;
an adjustable light blocking element connected to the ballast element;
at least two suspension cords associated with the light blocking element; and
a suspension mechanism connected to the suspension cords to adjust the light blocking element, the suspension mechanism having;
two rotary winding drums each respectively adapted to wind and unwind a respective suspension cord;
two rotary loading drums adapted for each respective suspension cord, each rotary loading drum further having an axle and a constant force spring having a first end and a second end, the first end of the spring being connected to the rotary loading drum and the second end of the spring being mounted on the axle;
a transmission system operatively connecting the rotary winding drum and at least one end of the spring to transmit a rotating movement at a differential rate between the rotary winding drum and the one end of the spring; and
each rotary loading drum is in operative engagement with each other and rotates at about the same rotational displacement rate. - View Dependent Claims (18, 19)
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20. A suspension mechanism for use in a window covering with a suspension cord, the suspension mechanism comprising:
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a first rotary drum adapted to wind and unwind the suspension cord;
a spring having a first end, and a second end mounted on an axle, the first end being rotatable with respect to the second end; and
a transmission system operatively connecting the first rotary drum and at least one end of the spring to transmit a rotating movement at a differential rate between the first rotary drum and the one end of the spring such that the first rotary drum rotates at a faster rate than an effective rotational displacement of the spring. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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Specification