This invention relates to a mechanism for controlling adjustment of a blind. The mechanism has been developed for controlling adjustment of a clutch roller blind and it will be convenient to hereinafter describe the invention with reference to this particular application. It ought to be appreciated however that the mechanism is applicable to other blind and curtain control mechanisms where a pull element, such as a chain or cord, is used. These blinds can include venetian and vertical.
A blind generally includes a length of flexible material that can be positioned adjacent a window or the like. A roller blind generally includes a mechanism is used to adjust the position of the material relative to the window. The mechanism includes a cylinder onto which the material is wound, and the cylinder is supported at its distal ends. A clutch roller mechanism includes pull element, such as a chain or cord, located at a distal end of the cylinder. The clutch is normally in an engaged condition whereby it prevents rotation of the cylinder. Pulling on the cord adjusts the condition of the clutch to a disengaged condition so as to allow the cylinder to rotate.
The blinds in general and the cord in particular are intriguing to young children who like to play games using the blind. They like to feel the blind moving over their face as they move through the blind. This can be dangerous for a number of reasons including where they get their heads caught in the loop of the cord. This can result in strangling of the child.
It would be preferable to provide a mechanism for controlling a blind that provided access to the cord to allow operation of the blind while minimising the risk of it being caught around the neck of a child.
A reference herein to a patent document or other matter which is given as prior art is not to be taken as an admission that that document or matter was, in Australia, known or that the information it contains was part of the common general knowledge as at the priority date of any of the claims.
According to this invention there is provided a mechanism for controlling adjustment of a blind or the like, the mechanism including, a fixable member which in use is fixed in position relative to the blind, a rotatable member located proximate the fixable member being rotatable relative to the fixable member about an axis of rotation to adjust the blind, an elongate member having a proximal end which is located proximate the rotatable member, the elongate member having a longitudinal axis, and a continuous pull element which interacts with the rotatable member, the pull element being movable relative to the fixable member to rotate the rotatable member, the pull element being arranged relative to the elongate member extending from the rotatable member towards a distal end of the elongate member and back towards the rotatable member such that movement of the pull element in a direction substantially perpendicular to the longitudinal axis of the elongate member is limited.
It is preferred that the mechanism include biasing means for urging the distal end of the elongate member away from the fixable member so as to apply tension to the pull element. It is further preferred that the elongate member is connected to the fixable member to allow the elongate member to pivot about the axis of rotation, relative to the fixable member. It is still further preferred that the connection is configured to limit pivoting of the elongate member to no more than 90° from a normal operating position. It is also preferred that the pull element is a continuous chain. It is also preferred that the rotatable member is a pulley.
It is preferred that the mechanism include a guide located at the distal end of the elongate member around which the pull element passes. It is preferred that the guide is a pulley that rotates as the pull element is moved.
It is preferred that the mechanism include a housing which houses the rotatable member, the housing includes a sleeve to accommodate the proximal end of the elongate member. Preferably the sleeve is hinged relative to the fixed member so as to allow the elongate member to be movable relative to the axis of rotation. Preferably the sleeve is hinged such that the elongate member is capable of pivoting relative to the fixed member in a plane in which the axis of rotation lies, i.e. the elongate member may be pivoted in a direction such that its longitudinal axis approaches being parallel to the axis of rotation. In practice, this means that the elongate member may be folded such that it lies against a blind to which the mechanism is attached for convenient packaging and installation. It is further preferred that the housing includes an abutment against which the biasing means abuts, and the proximal end of the elongate member also abuts against the abutment to limit movement of the elongate member along its longitudinal axis, i.e. its movement towards the fixable and rotatable members is limited. It is preferred that the biasing means is a compression spring. In this way, the ability for slack to form in the pull element along the elongate member is curtailed.
It is preferred that the fixable member includes a fixed shaft having a longitudinal axis that is coincident with the axis of rotation.
It is also preferred that the longitudinal axis of the elongate member intersects the axis of rotation of the rotatable member when the elongate member is in a normal operating position.
It is preferred that the mechanism include a cylinder for carrying a blind which is rotatable on rotation of the rotatable member.
It is preferred that the mechanism include a driven member interacting with the rotatable member and a clutch interacting with the fixable member and the driven member, wherein the clutch adopts a disengaged condition when the rotatable member is rotated so as to allow rotation of the driven member, and adopts an engaged condition upon cessation of rotation of the rotatable member to prevent further rotation of the driven member. It is further preferred that the driven member is mounted on the rotatable member. It is still further preferred that member includes a barrel portion, and the clutch includes at least one helical spring associated with the fixable member, the helical spring being substantially coaxial with the axis of rotation, the helical spring including a protrusion at each end of the spring extending radially of the axis of rotation, whereby the protrusions are engaged by the barrel portion to expand the helical spring when adopting the disengaged condition. It is preferred that the driven member includes a rib that engages the protrusion on the helical spring to urge the helical spring to contract when adopting the engaged condition. It is further preferred that the at least one helical spring includes two helical springs, whereby the protrusions at one end of each spring are substantially longitudinally aligned, and the protrusions at an opposing end of each spring are also substantially longitudinally aligned.
It will be convenient to hereinafter describe the invention with reference to the accompanying drawings which illustrate one preferred embodiment of the invention. The specifics of the illustrations and detailed description is not intended to limit the broad definition of the invention as herein before described.
The mechanism illustrated in
Referring now to
The rotatable member 14 includes a barrel portion 18 and a pulley portion 19. The barrel portion 14 is supported on the shaft 17 by the first bearing 10 and the second bearing 12. The pulley portion illustrated in
The shaft 17 of the fixable member 11 also provides support for the clutch 13. The preferred clutch illustrated is in the form of a pair of helical springs 21, 22 with each helical spring 21, 22 having a protrusion 21a, 21b, 22a, 22b at each end of the respective springs 21, 22. Each protrusion 21a, 22a, 21b, 22b extends radially of the shaft 17 and locates within a slot 23 formed in the barrel portion 18 of the rotatable member 14. The helical springs 21, 22 and the barrel portion 18 interact so that when the chain is pulled, the springs 21, 22 are urged to expand radially and allow the rotatable member 14 to rotate about the shaft 17. Furthermore the helical springs contract when the chain is not pulled so as to grip the shaft. With the protrusions 21a, 21b, 22a or 22b presenting a barrier to rotation of the rotatable member 14 by urging on the driven member 16. It should also be noted that whilst a single helical spring would suffice, it is preferable to include a pair of helical springs namely a right hand helical spring and a left hand helical spring. This combination of a right handed and left handed helical spring can counteract the tendency of the driven member to rotate either clockwise or anti-clockwise depending on the way in which the blind has been wound on to the cylinder.
The shaft 17 also supports the third bearing 15 which in turn supports the driven member 16. The driven member 16 is located on the barrel portion 18 and interacts with the rotatable member 14 and the cylinder 3 (see
A boss portion 24 of the fixable member 11 interacts with the housing 9 so as to centrally locate the fixable member 11 relative to the housing 9. The housing 9 includes a centrally located aperture to accommodate the boss portion 24. In this embodiment, the housing 9 may be rotatable relative to the boss portion 24, however it is preferred that rotation be limited to no more than 90°. The boss portion 24 and housing 9 may include a lug and stop arrangement (not shown) to limit the rotation. More specifically when the mechanism 2 is installed it is preferred that the housing 9 be rotatable to 45° either side of the vertical. This will allow the elongate member 6 to pivot out from the window to allow a user to access the pull element 8 more easily. The housing 9 also is shaped to accommodate the plate portion 24 so that the axis YY of the elongate member 6 will still intersect the axis XX, while the housing 9 rotates relative to the plate portion 24. The housing 9 includes a sleeve 25 which accommodates a proximal end 26 of the elongate member 6. The sleeve 25 need not entirely surround the proximal end 26 of the elongate member 6, so long as the sleeve provides a guide or passage for movement of the elongate member towards and away from the axis XX. The elongate member 6 illustrated includes a capping 29 which is also located within the sleeve 25 of the housing 9 when the mechanism is assembled. The housing 9 also includes an abutment 27 which interacts with a biasing means 28, illustrated in the form of a compression spring, acting between the abutment 27 and the capping 29 to urge the elongate member 6 away from the housing 9.
The pull element 8 is arranged so as to extend from the rotatable member 14 towards a distal end of the elongate member 6, such that movement of the pull element 8 in a direction substantially perpendicular to the longitudinal axis of the elongate member 6 is limited. It is preferred that the pull element 8 interact with the distal end of the elongate member 6 so as to maintain tension on the pull element 8. This may be achieved in any suitable manner, however in the embodiment illustrated in
Referring now to
In
In
In
According to the present invention, the pull element 8 can thus be exposed for use for the majority of its length while not allowing a dangerous loop to form which could present a choking hazard. If the pull element were substantially enclosed in a conduit, with only a limited portion being exposed to activate a blind, this may be a relatively safe arrangement but would be highly inconvenient when trying to adjust the blind due to the short stroke of pull element that can be drawn at any one time.
Various alterations and/or additions may be introduced to the mechanism as hereinbefore described without departing from the spirit or ambit of the invention.
Number | Date | Country | Kind |
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2010901847 | Apr 2010 | AU | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/AU2011/000499 | 5/2/2011 | WO | 00 | 12/11/2012 |
Publishing Document | Publishing Date | Country | Kind |
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WO2011/134022 | 11/3/2011 | WO | A |
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Lava, Aaron, et al., Australian Patent Application No. 2010901847, International-Type Search Report, Jul. 22, 2010. |
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Number | Date | Country | |
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20130068405 A1 | Mar 2013 | US |