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FIELD 
       [0001]    The present invention relates to a connector, such as, but not being limited to, a connector for extending a shaft in window furnishings. 
       BACKGROUND 
       [0002]    Roller blind systems typically include a tube with sheet material (e.g. fabric) rolled around the tube. The tube is held in a fixed position, and is rotated to raise or lower the material, for example, over a windowed area to serve as a blind. A weight may be attached to one end of the material to assist in lowering the blind. The inside of the tube may be fitted with a booster assembly, which includes a spring having one end held in a fixed position relative to tube, and a component that engages the other end of the spring for rotation with the tube. As the blind is lowered, the spring is made to tighten to provide a counterbalancing (generally upward) force to assist in raising the blind. 
         [0003]    For blinds made of a heavy material, the counterbalancing force provided by one booster assembly may not be sufficient for effectively or conveniently raising the blind. A similar problem exists where a larger roller blind (i.e. of greater span) is required to extend over a larger windowed area, since a larger blind increases its overall weight and the counterbalancing force exerted by a single spring booster assembly may not be sufficient for effective/convenient retraction of the blind. Another problem is the impracticality of manufacturing shafts at custom lengths, and to custom make and fit booster assemblies onto such a shaft. Custom manufacture and fitting is laborious and hence an expensive option. It is therefore desired to address one or more of the above issues, or to at least provide a useful alternative. 
       SUMMARY 
       [0004]    According to the present invention there is provided a connector for a blind control mechanism, said mechanism including:
       i) a cylinder rotatable relative to two or more different shafts;   ii) drive means connected to the cylinder and being operable to rotate the cylinder in either a blind extending direction or a blind retracting direction; and   iii) at least two biasing means connected to said cylinder, each said biasing means being responsive to rotation of the cylinder in a blind extending direction to store energy and being responsive to rotation of said cylinder in a blind retracting direction to release said stored energy and thereby apply a turning force to the cylinder, said turning force acting in the blind retracting direction;
 
said connector having a body for coupling an end portion of one of said biasing means to one of said shaft portions, and for coupling respective end portions of two adjacent said shafts together.
       
 
         [0008]    The present invention also provides a connector for a blind control mechanism, said mechanism including:
       i) a cylinder rotatable relative to two or more different shaft portions;   ii) drive means connected to the cylinder and being operable to rotate the cylinder in either a blind extending direction or a blind retracting direction; and   iii) at least two biasing means connected to said cylinder, each said biasing means being responsive to rotation of the cylinder in a blind extending direction to store energy and being responsive to rotation of said cylinder in a blind retracting direction to release said stored energy and thereby apply a turning force to the cylinder, said turning force acting in the blind retracting direction;
 
said connector having a body for coupling an end portion of one of said biasing means to one of said shaft portions, said connector having an end portion formed for connecting with another of said shaft portions located on a separate shaft.
       
 
         [0012]    The present invention also provides an assembly for use in window furnishings including a connector as described above. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    A preferred embodiment of the present invention is herein described, by way of example only, with reference to the accompanying drawings, wherein: 
           [0014]      FIG. 1  is a perspective view of two spring booster assemblies; 
           [0015]      FIG. 2  is an exploded perspective view of a spring booster assembly including a connector according to a first embodiment; 
           [0016]      FIG. 3  is an exploded side view of a spring booster assembly including a connector according to a first embodiment; 
           [0017]      FIG. 4  is a perspective view of two spring booster assemblies; 
           [0018]      FIG. 5  is an exploded perspective view of a spring booster assembly including a connector according to a second embodiment; 
           [0019]      FIG. 6  is an exploded side view of a spring booster assembly including a connector according to a second embodiment; 
           [0020]      FIG. 7  is an exploded perspective view of a roller blind system; 
           [0021]      FIG. 8  is an exploded perspective view of a roller blind system using a connector according to a first embodiment; 
           [0022]      FIG. 9  is an exploded perspective view of a roller blind system using a connector according to a second embodiment; and 
           [0023]      FIGS. 10 ,  11 ,  12 ,  13 ,  14  and  15  show various configurations of a roller blind system using one or more connectors. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0024]      FIG. 1  is a perspective view of two booster assemblies  100  and  102  for use in a roller blind system. Each booster assembly  100  and  112  includes a shaft  104  and  106 , a biasing means  108  and  110  (e.g. a coil spring), a connector, and a tail member  112  and  114 . An example of a male form of a connector is shown in  FIG. 2 , which includes an adapter  116  and connecting piece  122 . An example of a female form of a connector is shown in  FIG. 3 , which includes a connecting piece  208 . The biasing means  108  and  110  of the booster assemblies  100  and  102  are preferably different coil springs that are wound in a single direction. 
         [0025]    The biasing means  108  and  110  fits over the different portions of different shafts  104  and  106 . The adapter  116  and  118  engages one end of the biasing means  108  and  110  and holds that end in a fixed position relative to the respective shaft  104  and  106 . As shown in  FIG. 2 , an adapter  116  includes a bore  116   b  formed through the adapter  116 , where one portion of the bore  116   b  has a cross-sectional shape corresponding to the cross-sectional shape of the shaft  104  to be received in that portion. This enables the bore  116   b  of the adapter  116  to form a locking fit with an outer surface of the shaft  104  so that the spring adapter  116  can engage and rotate together with the shaft  104 . The bore  116   b  includes another portion that is shaped to receive a connecting piece  122 . The adapter  116  includes an outer portion  116   c  for engaging with the biasing means  108 . For example, the adapter  116  may form an interference fit with the biasing means  108  (e.g. by having the outer surface  116   c  of the adapter  116  threaded for receiving a portion of the biasing means  108 ). Alternatively, the outer surface  116   c  of the adapter  116  may include one or more grooves forming a ray section for receiving a correspondingly shaped hook end of the spring. 
         [0026]    The tail member  112  and  114  freely rotates about the shaft  104  and  106 , and engages the other end of the biasing means  108  and  110 . The tail member includes one or more slots  114   a,    114   b,    114   c  and  114   d  for receiving fins formed on the inside surface of a hollow tube (not shown) in which the booster assembly  100  and  102  fits. A flexible sheet material (e.g. fabric) is wrapped around the outside of the tube so that the selective rotation of the tube controls the extension or retraction of the sheet material over a predefined area (e.g. a window). 
         [0027]    As shown in  FIG. 1 , the adapter  118  of at least one spring booster assembly  102  is fitted to a head member  120  that mounts the spring booster assembly  102  to a mounting bracket (not shown). When the tube selectively rotates to extend the sheet material on the tube over a predefined area, the corresponding rotation of the fins inside the tube drives the tail member  112  and  114  to rotate, and this in turn gradually tightens the spring  108  and  110 . As the biasing means  108  and  110  gradual tightens, the biasing means  108  and  110  gradually asserts a greater counterbalancing force to assist rotation of the tube in the opposite direction to retract the sheet material onto the tube. 
         [0028]    Booster assemblies  100  and  102  can be made from standard components, and can be made in a range of different standard sizes. A cost effective way to produce roller blinds of any size is to allow combinations of standard boost assemblies  100  and  102  to be combined using a connector so that the booster assemblies operate as a single unit. 
         [0029]    A connecting piece  122 , as shown in  FIG. 2 , includes a body having a first end portion  126  for fitting into a hollow end portion of a first shaft  104 , and a second end portion  124  for fitting into a hollow end portion of a second shaft  106 . The first and second shafts  104  and  106  may each be a square tube shaft. Alternatively, the first and second shafts  104  and  106  may be a solid axle including a hollow end portion for receiving the connecting piece  122 . When the first and second end portions  124  and  126  of the connecting piece  122  are fitted into the hollow portions of respective the first and second shafts  104  and  106 . Accordingly, the rotation of one of the shafts  104  or  106  along its longitudinal axis engages the connecting piece  122  to rotate, whereby rotation of the connecting piece  122  engages the other shaft  104  or  106  to rotate along its longitudinal axis. In the configuration shown in  FIGS. 1 ,  2  and  3 , the connecting piece  122  and shafts  104  and  106  rotate along a common axis. The connecting piece  122  is preferably made as a single piece, as shown in  FIG. 2 . 
         [0030]    The first and second end portions  124  and  126  of the connecting piece  122  each have a cross-sectional shape corresponding respectively to the cross-sectional shape of the hollow portion of the first and second shafts  104  and  106 , so as to form a close fit for locking engagement when the connecting piece  122  rotates with a respective portion of the shafts  104  and  106 . 
         [0031]    The cross-sectional shape of the hollow portion of the first and second shafts  104  and  106  is preferably quadrilateral (e.g. a recess with a square-shaped cross-section), although the cross-section of the hollow can have any shape. The cross-section of each of the first and second end portions  124  and  126  has a shape corresponding to the shape of the cross-section of the respective shafts  104  and  106 . For example, when the connecting piece  122  is received in the shafts  124  and  126 , the outer surface of the end portions  124  and  126  rests adjacent to the corresponding inner surface of the hollow portion of the shaft  104  and  106 . 
         [0032]    The connecting piece  122  includes an enlarged portion  128  located between the first and second end portions  124  and  126 . The cross-section of the enlarged portion  128  of the connecting piece  122  is generally greater than the cross-section of the first and second end portions  124  and  126  so as to minimise movement of said shafts  104  and  106  along the respective end portions  124  and  126  and beyond the enlarged portion  128 . The enlarged portion  128  may, for example, have a circular cross-section. 
         [0033]    The connecting piece  122  has respective holes  124   a  and  126   a  formed through a part of the body of the connecting piece  122  at the first and second end portions  124  and  126 . The first and second shafts  104  and  106  each has respective holes  104   a  and  106   a  formed through a part of the shaft. When the first and second end portions  124  and  126  are fitted into the hollow portions of the respective shafts  104  and  106 , the holes  104   a  and  106   a  and recesses  124   a  and  126   a  can be linearly aligned for receiving a locking member (not shown) that securely retains the connecting piece  122  to the respective shafts  104  and  106 . The locking member may include a pin (such as a split pin or cotter pin). 
         [0034]    As shown in  FIG. 2 , an adapter  116  may include a hole  116   a  formed through a part of the adapter  116 . During assembly of an extensible booster  100 , the adapter  116  is fitted over an end portion of the shat  104  so that the holes  116   a  and  104   a  are linearly aligned. The connecting piece  122  is passed through the bore of the adapter  116  and fitted into a hollow portion of the shaft  104 . The biasing means  108  is fitted over the shaft  104  and made to engage the outer surface of the adapter  116 . The tail member  112  is then fitted over the shaft  104  and made to engage the other end of the biasing means  108 . 
         [0035]    An extensible booster assembly  100  may connect to and engage with another extensible booster assembly  100 . Alternatively, an extensible booster assembly  100  may connect and engage with a standard booster assembly  102  for mounting onto a mounting bracket. It can be appreciated that a combination of multiple booster assemblies  100  and  102  can be connected to each other for combined operation as a single booster unit. This enables a roller blind of any length to be easily made simply by combining different booster assemblies with different standard shaft lengths. Also, each assembly  100  and  102  has an independent biasing means (e.g. a spring) so that the combination of multiple boost assemblies can provide a greater combined counterbalancing force for retracting the blind. 
         [0036]      FIGS. 4 ,  5  and  6  show another embodiment of the connector (including a connecting piece  208 ) for connecting two solid shafts  204  and  206 . As shown in  FIG. 5 , the connecting piece  208  has a body including a bore  210  formed through the connecting piece  208  along its longitudinal axis. The bore  210  forms two openings on opposite sides of said connecting piece  208 . The bore  210  is shaped for receiving a portion of a first shaft  206  and a portion of a second shaft  204 . When the connecting piece  208  receives the end portions of the shafts  204  and  206 , the rotation of one of the shafts  204  or  206  along its longitudinal axis engages the connecting piece  208  to rotate, whereby the rotation of the connecting piece  208  engages the other shaft  204  or  206  to rotate along its longitudinal axis. In the configuration shown in  FIGS. 4 ,  5 , and  6 , the connecting piece  208  and shafts  204  and  206  rotate along a common axis. The connecting piece  208  is preferably made as a single piece, as shown in  FIG. 5 . 
         [0037]    The bore  210  has a cross-sectional shape corresponding to the cross-section of said first and second shafts. The connecting piece  208 , as shown in  FIG. 5 , engages with the biasing means  108  in the same way as the adapter  116  of the connector as shown in  FIG. 2 . The cross-sectional shape of the bore  210  may, for example, be quadrilateral (and preferably square), although it should be understood that the cross-sectional shape should simply correspond with the cross-sectional shape of the shaft, and could be of any shape. 
         [0038]      FIG. 7  is an exploded perspective view of a roller blind system incorporating both an extensible and a standard booster assembly  100  and  102  that are engaged to operate together by a connector of the type described with reference to  FIGS. 1 ,  2  and  3  . In this embodiment of a roller blind system, a user gently pulls on a lower portion of the blind  702 , and the tube  704  automatically rotates (by the force exerted by the biasing means in the assemblies  100  and  102 ) in a counter-clockwise direction to retract the blind. 
         [0039]      FIG. 8  is an exploded perspective view of another embodiment of a roller blind system incorporating both an extensible and a standard booster assembly  100  and  102  that are engaged to operate together by a connector as describe with reference to  FIGS. 1 ,  2 , and  3 . This embodiment is similar to the embodiment shown in  FIG. 7 , except that the raising and lowering of the blind  804  by selective rotation of the tube  806  is controlled by a user operating a chain-driven winder member  802 . 
         [0040]      FIG. 9  is an exploded perspective view of another embodiment of a roller blind system incorporating both an extensible and a standard booster assembly  100  and  102  that are engaged to operate together by a connector as describe with reference to  FIGS. 4 ,  5 , and  6 . The operation of this embodiment is similar to the embodiment described with reference to  FIG. 7 . 
         [0041]    In this specification, unless the contrary is expressly stated, where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was at the priority date, publicly available, known to the public, part of common general knowledge; or known to be relevant to an attempt to solve any problem with which this specification is concerned. 
         [0042]    The word ‘comprising’ and forms of the word ‘comprising’ as used in this description and in the claims does not limit the invention claimed to exclude any variants or additions. 
         [0043]    Modifications and improvements to the invention will be readily apparent to those skilled in the art. Such modifications and improvements are intended to be within the scope of this invention.

Summary:
A connector for a blind control mechanism including a cylinder rotatable relative to two or more different shafts, drive means connected to the cylinder and being operable to rotate the cylinder in either a blind extending direction or a blind retracting direction; at least two biasing means connected to the cylinder, each biasing means being responsive to rotation of the cylinder in a blind extending direction to store energy and being responsive to rotation of the cylinder in a blind retracting direction to release the stored energy and thereby apply a turning force to the cylinder, the turning force acting in the blind retraction direction. The connector having a body for coupling an end portion of one of the biasing means to one of the shaft portions and for coupling respective end portions of two adjacent the shafts together.