Adjustable spring system and method for roller blinds

Abstract

A method for altering the spring constant (k) of a torsion spring for a roller blind, the method including (i) locating a dampener at a predetermined length along a longitudinal axis of the torsion spring, and (ii) tightening an end of the torsion spring against the dampener to increase the spring constant. Further disclosed is a roller blind system having a cylinder, a fabric attached to the cylinder for winding and unwinding from said cylinder, a torsion spring and a damper moveable along the longitudinal axis of the spring.

Claims

1. A method for altering the spring constant (k) of a torsion spring for a roller blind, the method including: locating a dampener at a predetermined length along a longitudinal axis of the torsion spring, wherein the dampener is located on a u-shaped rod, and the combined parts of the dampener and the rod are slidable on a shaft along the longitudinal axis of the torsion spring, and tightening an end of the torsion spring against the dampener to increase the spring constant.

2. The method according to claim 1 wherein tightening the end of the torsion spring against the dampener reduces the operating length of the torsion spring and provides a pre-tension effect.

3. A roller blind system including: a cylinder having a cylinder length and a cylinder diameter, a fabric attached to said cylinder for winding and unwinding from said cylinder, the fabric having a fabric length, a fabric weight, a fabric width, a thickness and a fabric height, a torsion spring having a first spring length, a longitudinal axis and operative to assist the cylinder in at least one direction of rotation, a damper moveable along the longitudinal axis of the torsion spring, wherein the damper k located on a u-shaped rod, and the combined parts of the damper and the rod are skiable on a shaft along the longitudinal axis of the torsion spring, wherein the damper is reversibly brought into contact with the torsion spring at a predetermined position so that a change in torque produced by the torsion spring upon rotation in a first direction balances a change in torque in a second, opposite direction which is produced by the weight of fabric as the cylinder rotates.

4. The roller blind system of claim 3 which additionally includes a weight bar extending along the width of the fabric.

5. The roller blind system according to claim 3 wherein the torque increase or decrease produced by the torsion spring upon rotation of the cylinder matches the increase or decrease in torque in the opposite direction that is produced by the weight of fabric as it is released from the cylinder during rotation of the cylinder.

6. The roller blind system according to claim 3 wherein the torque increase or decrease produced by the torsion spring upon rotation of the cylinder matches the increase or decrease in torque in the opposite direction that is produced by the weight of fabric as it is rolled onto the cylinder.

7. A roper blind system including: a cylinder having a cylinder length and a cylinder diameter, a fabric attached to said cylinder for winding and unwinding from said cylinder, the fabric having a fabric length, a fabric weight, a fabric width, a thickness and a fabric height, a torsion spring having a first spring length, a longitudinal axis and operative to assist the rotation of the cylinder in at least one direction of rotation, a clutch adjacent a first end of the torsion spring, a damper moveable along the longitudinal axis of the torsion spring, wherein the damper is located on a u-shaped rod, and the combined parts of the damper and the rod are slidable on a shaft along the longitudinal axis of the torsion spring, wherein the damper is reversibly brought into contact with the torsion spring at a predetermined position so that a change in torque produced by the torsion spring upon rotation of the cylinder in a first direction balances a change in torque in a second, opposite direction which is produced by the weight of fabric as the cylinder rotates.

8. The roller blind system of claim 7 which additionally includes a weight bar extending along the width of the fabric.

9. The roller blind system according to claim 7 wherein the torque increase or decrease produced by the torsion spring upon rotation of the clutch balances the increase or decrease in torque in the opposite direction that is produced by the weight of fabric as it is released from the cylinder during rotation of the cylinder.

10. The roller blind system according to claim 7 wherein the torque increase or decrease produced by the torsion spring upon rotation of the clutch matches the increase or decrease in torque in the opposite direction that is produced by the weight of fabric as it is rolled onto the cylinder.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further disclosure, objects, advantages and aspects of preferred and other embodiments of the present application may be better understood by those skilled in the relevant art by reference to the following description of embodiments taken in conjunction with the accompanying drawings, which are given by way of illustration only, and thus are not limitative of the disclosure herein, and in which:

(2) FIG. 1 illustrates a standard clutch operated roller blind of the prior art;

(3) FIG. 2 illustrates a typical mechanism for a cylinder of the prior art for a roller blind, which mechanism is normally fitted inside the cylinder tube;

(4) FIG. 3 illustrates a side view of a dampener according to the present invention;

(5) FIG. 4 is an end view of the dampener of FIG. 3;

(6) FIG. 5 illustrates the dampener of FIG. 3 relative to other elements at one end of the spring roller blind system;

(7) FIG. 6 illustrates the dampener of FIG. 3 relative to other elements at the other end of the spring roller blind system;

(8) FIG. 7 illustrates the combination of elements depicted in FIG. 5 and FIG. 6 to produce a spring roller blind system.

(9) FIG. 8 illustrates a further embodiment of the invention incorporating a clutch in expanded view.

(10) FIG. 9 illustrates the embodiment of the invention shown in FIG. 8 with a view of the clutch as assembled.

DETAILED DESCRIPTION

(11) TABLE-US-00001 List of Parts 1 cylinder tube 3 fabric 5 weight bar 7 idler 9 control device 11 cord 21 latch device 22 rod 23 helical spring 24 fixing device 26 side of fixing device 27 compression spring 28 nut 30 grooves in nut 31 idler 40 dampener 41 cover 42 U-shaped rod 45 torsion spring 47 rod shaft (square cross section) 49 bearing 51 bracket 55 lug

(12) FIG. 1 illustrates a standard clutch operated roller blind of the prior art comprising a cylinder tube (1), which is a metal or other material tube around which fabric (3) is wrapped. The cylinder tube (1) supports the weight of the fabric including the weight bar (5) which is heavy, and causes the fabric (3) to remain smooth and hang straight. One end of the cylinder tube (1) is supported by an idler (7) that is inserted inside and allows the tube to rotate freely even when supported by a bracket. The other end of the cylinder tube (1) is fitted with a clutch or other control device (9). The clutch allows the user to extend or retract the blind and prevents the fabric from unrolling from the cylinder under the fabric's own weight. A loop of beaded or plain cord (11) can be pulled by a user to rotate the internal components of the control device (9) and cause the rotation of the cylinder tube (1) to extend (lower) or retract (raise) the fabric (3) over an area or opening to be covered.

(13) When the fabric (3) is fully retracted, the only torque exerted on the cylinder tube (1) is due to the weight of the weight bar (5). The torque exerted upon the cylinder increases as the fabric drops and decreases when it is raised. If the fabric (3) and base rail (5) are relatively light, then the roller blind can easily be operated manually or with minimal strain on a small motor.

(14) However, if the fabric and base rail are particularly heavy, such as when the area to be covered by the blind is very large, the roller blind may also be spring assisted. The spring winds and tightens when the blind is lowered by an operator so that upon lifting the blind, the spring can release the stored energy to apply rotary force (torque) and assist the operator to roll the fabric back onto the cylinder and lift the blind. Typically, the spring used is a constant rotational tension spring, also called a torque spring.

(15) FIG. 2 illustrates a typical mechanisms for a spring assisted cylinder of the prior art, which mechanism is normally fitted inside the cylinder tube which is fixed to a clutch or control unit. The mechanism consists of a rod (22) around which is fitted a helical spring (23). This is fixed between the latch device (21) and a fixing device (24) on the rod. Rotation of the cylinder tube and the latch device (21) in the direction of the arrow causes tensioning of the spring (23), that is, the fabric is pulled down. The other end of the cylinder tube (23) has an idler (31).

(16) The side (26) of a fixing device (24) which faces away from the clutch (21) supports one end of a compression spring (27), the other end of which is supported against a nut (28). This can turn around a thread (29) on the extension of the rod (22). The nut (28) is provided with one or more groves (30) which cooperate with a longitudinal tongue in the cylinder tube (not shown in this view).

(17) It is important for balanced operation of the roller blind that the spring dimensions (such as wire diameter, coil diameter, coil length and material of construction) represented by its spring constant (k) are chosen to match the characteristics of the blind. The length of the spring determines the maximum number of rotations it will be able to make, which in turn dictates the height of the blind for a given cylinder. The change in torque applied by a spring with each rotation is a function of its spring constant (k).

(18) FIG. 3 illustrates one embodiment of a dampener (40) according to the present invention in side view and FIG. 4 illustrates the same dampener in end view. Preferably the dampener is a moulded polymer, but could be made from metal or other materials.

(19) Operation of the spring roller blind system is best described with reference to FIG. 7 illustrates the combination of elements depicted in FIG. 5 and FIG. 6.

(20) FIG. 5 illustrates how the dampener (40) is positioned relative to other elements of the spring blind roller system. The dampener (40) is located on a rod (42) which in this embodiment is of substantially U-shaped. In use the rod (42) and dampener (40) reside within the torsion spring (45) which is shown in cross section. In the first embodiment, the recess of the U-shaped rod (42) receives a shaft (47) of square cross section which carries a pin end control unit at one end. When mounted on a wall or other structure the idler is supported on a bracket (51). In a second embodiment, the recess of the U-shaped rod (42) receives a shaft (47) of square cross section which carries a spring assist/idler (49) attached to the clutch at one end. When mounted on a wall or other structure the clutch is supported on a bracket (51).

(21) FIG. 6 illustrates how the dampener (40) is positioned relative to other elements at the other end of the spring blind roller system. Specifically it shows the dampener (40) in position on the rod (42) at one end of which is a rotating bearing (49) which in use would rotate in unison with the cylinder and provides a centre support inside the cylinder. A lug (55) holds the rotating bearing in position on the U-shaped rod (42) and rod shaft (47) as shown in FIG. 7.

(22) In an alternative embodiment, the bearing (49) can be fixed to one opposing end of the torsion spring and can cause the spring to tension as the cylinder rotates, while the other end of the torsion spring is fixed at the opposite end.

(23) Specifically, the dampener (40) is fixed to the U-shaped rod (42) and the combined parts can be slid along the longitudinal axis and located in any desired position within the spring (45). In the first embodiment, rotation of the cylinder causes rotation of the housing (s really the outer housing around 49), which in turn turns the first or second end of the spring (45), reducing the coil diameter and concomitantly tightening against the dampener (40). As a result the spring coils between the control unit and the dampener (40) tighten, but the coils between the dampener (40) and the rotating bearing (49) do not tighten. Thus, the dampener effectively reduces the number of active coils, altering the k value of the spring. In this manner the operating dimensions of the spring can be matched to the operating dimensions of the blind.

(24) FIG. 7 illustrates the individual elements depicted in FIGS. 5 and 6 when assembled.

(25) FIGS. 8 and 9 illustrate a further embodiment of the invention incorporating a clutch in exploded (FIG. 8) and assembled (FIG. 9) views. While the embodiment depicted in FIGS. 5, 6 and 7 illustrate the spring fitted at the idler end of the blind system, the embodiment shown in FIGS. 8 and 9 illustrate the spring fitted at the clutch end of the blind system, the clutch being driven manually by a chain, or preferably being driven by a small motor.

(26) For purposes of description herein, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” “interior,” “exterior,” and derivatives thereof shall relate to the invention as oriented in FIG. 1. However, it is to be understood that the invention may assume various alternative orientations, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawing, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise. Additionally, unless otherwise specified, it is to be understood that discussion of a particular feature of component extending in or along a given direction or the like does not mean that the feature or component follows a straight line or axis in such a direction or that it only extends in such direction or on such a plane without other directional components or deviations, unless otherwise specified.

(27) While this invention has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modification(s). This application is intended to cover any variations uses or adaptations of the invention following in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth.

(28) As the present invention may be embodied in several forms without departing from the spirit of the essential characteristics of the invention, it should be understood that the above described embodiments are not to limit the present invention unless otherwise specified, but rather should be construed broadly within the spirit and scope of the invention as defined in the appended claims. The described embodiments are to be considered in all respects as illustrative only and not restrictive.

(29) Various modifications and equivalent arrangements are intended to be included within the spirit and scope of the invention and appended claims. Therefore, the specific embodiments are to be understood to be illustrative of the many ways in which the principles of the present invention may be practiced. In the following claims, means-plus-function clauses are intended to cover structures as performing the defined function and not only structural equivalents, but also equivalent structures.

(30) “Comprises/comprising” and “includes/including” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof. Thus, unless the context clearly requires otherwise, throughout the description and the claims, the words ‘comprise’, ‘comprising’, ‘includes’, ‘including’ and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”.