Patent Document

CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims priority under 35 U.S.C. 119 from Australian Patent Application No. 2010900559, filed on Feb. 12, 2010, the contents of which are incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The present invention relates to improvements in hinges, and is particularly, though not exclusively, applicable to hinges for self-closing gates and doors. 
     BACKGROUND TO THE INVENTION 
     Self-closing (and self-opening) gates are in common use, particularly in situations which require increased safety. For example, it is mandatory in some countries to provide self-closing gates for swimming pool fences, to prevent unsupervised access by small children in the event that other persons have forgotten to close the gate. Similarly, self-closing gates are often employed in households to prevent toddlers from accessing stairways and other potentially hazardous areas. 
     Gates of this type generally include a helical spring-loaded hinge which produces a torque to bias the hinge towards the closed (or open, as the case may be) position. A problem which arises in relation to such gates is that they vary in dimension and weight, and so the spring tension in the hinge must be adjusted accordingly in order to have the gate close or open at appropriate speed. 
     One solution to the problem, as proposed by Australian patent no. 666491, is to provide a coupling element connected to the spring. The coupling element includes a head portion with a circular top section and a hexagonal intermediate section which engages a matching hexagonal engagement surface in an aperture of the spring housing. The top section includes a slot to accommodate a screwdriver. When it is desired to adjust the spring tension, the person installing the gate inserts a screwdriver into the slot and applies pressure to disengage the coupling element so that it can be turned to a different orientation. A disadvantage of this arrangement is that it requires the simultaneous application of a linear force along the spring axis and a rotational force about the spring axis. This is a relatively unnatural movement which can cause inconvenience to the installer. Use of a screwdriver can also cause inconvenience in that the knuckles on the installer&#39;s hand may be obstructed by the hinge or the gate to which it is mounted. 
     It is therefore desirable to provide a hinge which has adjustable tension, but which is easier to install and adjust than known hinges of the type described above. 
     SUMMARY OF THE INVENTION 
     Accordingly, the present invention provides, in one aspect, a hinge including first and second hinge members movable between an open position and a closed position, 
     the first hinge member including a substantially cylindrical body portion having a longitudinal axis about which the second hinge member is rotatable to move the hinge between the open position and the closed position; 
     the body portion housing biasing means having an end fixed relative to the second hinge member, the biasing means being in engagement with an adjustment member, the adjustment member being fixed with respect to the first hinge member; 
     wherein the adjustment member includes a ratchet means to move the adjustment member in a first direction to increase the tension in the biasing means. 
     Preferably, a first end of the biasing means is fixed relative to the second hinge member and a second end of the biasing means is engaged with the adjustment member. 
     The unidirectional movement of the ratchet means allows an installer to apply a purely rotational force in order to increase the spring tension. This provides for a much easier tension adjustment method than in known arrangements. 
     In a particularly preferred embodiment, the ratchet means is a releasable ratchet means. 
     The releasability of the ratchet means allows the tension to be reset to its initial level without disassembling the hinge. 
     In another preferred embodiment, the ratchet means includes a plurality of asymmetric teeth, each of the teeth having a first inclined face which is adapted to slide in the first direction over one or more stops located on the internal surface of the body portion, and a second face which is engageable with any one of the stops to fix the position of the second end of the biasing means relative to the first hinge member. 
     Preferably, the adjustment member includes a tool-engaging surface (in the form of a recess or projection) shaped to receive a complementarily shaped tool for moving the adjustment member in the first direction. For example, the adjustment member may contain a hexagonal recess to receive a hex key, or a star-shaped recess to receive a hexalobular tool such as those marketed under the trade mark TORX. An unusually-shaped recess or projection can be advantageous in prevention of tampering since a child is unlikely to be in possession of a tool with an appropriately shaped head. 
     In a particularly preferred embodiment, the adjustment member includes a tool-receiving portion containing the tool-engaging surface, the tool-receiving portion being detachably engaged with a tooth portion which includes the asymmetric teeth. In this embodiment, the tool-engaging surface is preferably a recess, the recess having an inner diameter and a base, the base including an aperture through which a pushing force may be applied to disengage the tooth portion from the stop or stops to release the ratchet means. Since the aperture will be narrower than the inner diameter of the recess, a different disengagement tool, for example a metal pin of appropriate length, having correspondingly smaller diameter would be required to be inserted into the aperture to disengage the tooth portion and decrease the spring tension. The requirement of a separate disengagement tool, or a specialised tool having a disengagement member at the end opposite the end which is received by the tool-receiving portion, further safeguards the hinge against tampering by children. 
     In one embodiment, the body portion includes an internal flange having a first surface for seating the tool-receiving portion of the adjustment member. The or each stop may be located on a second surface of the internal flange located opposite the first surface. 
     The or each stop may be an asymmetric tooth having an inclined face over which the first inclined face of each tooth of the tooth portion is adapted to slide. 
     The tooth portion may include a slot or recess to receive one end of the biasing means to engage the biasing means with the adjustment member. 
     In another aspect, the present invention provides a kit of parts for a hinge, including: 
     first and second hinge members movable, in use, between an open position and a closed position, 
     the first hinge member including a substantially cylindrical body portion having a longitudinal axis about which the second hinge member is rotatable to move the hinge between the open position and the closed position; and 
     biasing means housable within the body portion and having a first end and a second end, the first end being fixable relative to the second hinge member and the second end being engageable with an adjustment member, the adjustment member being fixed with respect to the first hinge member; 
     wherein the adjustment member includes a ratchet means, preferably a releasable ratchet means, to move the adjustment member in a first direction to increase the tension in the biasing means. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred embodiments of the invention will now be described by way of non-limiting example only by reference to the accompanying drawings, in which: 
         FIG. 1  is a partially cut-away plan view of a hinge according to the present invention; 
         FIG. 2  is a partially cut-away perspective view of the hinge of  FIG. 1 ; 
         FIG. 3  is a cross-section through one of the hinge members of  FIG. 2 ; and 
         FIG. 4  is a partial exploded view of the hinge of  FIGS. 1 and 2 . 
     
    
    
     DESCRIPTION OF PREFERRED EMBODIMENT 
     Referring now to  FIGS. 1 and 2 , there is shown a hinge  10  in its closed position, having first hinge member  12  and second hinge member  11 . The hinge  10  has holes  14 ,  15  for receiving fasteners, for example bolts, to secure the first and second hinge members to a post and gate (not shown), respectively. It will also be appreciated that the hinge can be used with a door, with the first hinge member  12  being mountable to the door frame and the second hinge member  11  being mountable to the door. 
     The holes  15  are preferably of elongate form to allow some adjustment of the height of the hinge relative to the gate or door during installation. Once the hinge is positioned appropriately, a further fastener can advantageously be attached through hole  16  to prevent movement of the hinge under the weight of the door or gate. 
     The first hinge member  12  has a substantially cylindrical body portion  30 . The second hinge member  11  may rotate about the longitudinal axis of the body portion  30  in order for the hinge to move between the closed and open position. 
     The second hinge member  11  has a pair of collars  21   a ,  21   b , one at each end. As best shown in  FIG. 4 , collar  21   a  acts as a sleeve for end piece  60 , which is engaged with the flattened terminal segment  52  of a first end  55  of a biasing means  50 , via slot  62 . The biasing means  50  of the embodiments shown in the Figures is a helical spring. 
     End piece  60  also has a hole (not shown) to receive a pin or bolt (or any other suitable fastener)  80 . When the hinge is assembled, pin or bolt  80  passes through the hole  81  in collar  21   a  into the hole in end piece  60  to secure end piece  60  to collar  21   a . A first end  55  of the helical spring  50  is thus fixed with respect to the end of the second hinge member  11 . 
     The second end  56  of helical spring  50  also has a flattened terminal segment (not shown) which fits into a slot (also not shown) in a tooth portion  42  of an adjustment member  40  ( FIG. 1 ), which also has a tool-receiving portion  41 . The adjustment member  40  is fixed with respect to the first hinge member  12  by virtue of the engagement of the second face  43   b  ( FIG. 2 ) of at least one of the teeth  43  with one of the stops  33 . Stops  33  are asymmetric teeth located on the lower surface of a flange  31  which is located on the inner surface of the body portion  30  of first hinge member  12 . 
     Since opposite ends  55 ,  56  of the helical spring are fixed with respect to respective hinge members  12 ,  11 , rotational movement of the hinge members with respect to each other, for example by opening a gate to which the hinge  10  is attached, will tend to create a torsional restoring force to move the hinge  10  back to its original (i.e. closed) position. 
     In  FIGS. 1 and 2  it will be observed that the asymmetric teeth  43  have an inclined face  43   a . When a hex key (not shown) of appropriate dimensions is placed in the hexagonal recess  44  of the tool-receiving portion  41  of adjustment member  40  and turned clockwise (as indicated by the arrows on tool-receiving portion  41 ), the inclined faces  43   a  of teeth  43  will slide over the inclined faces  33   a  of stops  33 , thereby compressing the spring  50  and increasing the longitudinal and torsional components of the tension as they do so. When the second faces  43   b  of teeth  43  pass the ends of the inclined faces  33   a  of the stops  33 , the longitudinal component will decompress the spring  50  in the longitudinal direction, but the spring  50  is restrained from decompression in the torsional direction as the teeth  43  bear against the second faces  33   b  of the stops  33 . 
     The teeth  43  of the adjustment member  40  thus act as a ratchet means by allowing rotational movement of the adjustment member  40  in one direction only (in this example, the clockwise direction). 
     The second faces  33   b ,  43   b  need not be non-inclined faces as shown in the Figures. Angled faces could also provide the ratcheting mechanism described above. 
     Referring now to the exploded view of  FIG. 4 , it will be seen that the tool-receiving and tooth portions  41 ,  42  of adjustment member  40  can be formed as two separate parts to form a releasable ratchet means. The portions  41 ,  42  are engaged via the placement of boss  72  of tooth portion  42  in the corresponding aperture  71  of tool-receiving portion  41 . In the assembled hinge, the lower surface  73  of tool-receiving portion  41  sits on the upper surface  32  of the flange  31  ( FIG. 3 ), while the teeth  43  of tooth portion  42  bear against the teeth  33  on the lower (opposite) surface of flange  31 . 
     The recess  44  has a substantially flat base in which is formed an aperture or bore (not shown), the aperture having smaller diameter than the recess  44  and passing through tool-receiving portion  41 . A tool having sufficiently small diameter may then be inserted into the aperture and a compression force applied to the boss  72  of tooth portion  42 . This serves to disengage the teeth  43  from stops  33 , allowing the spring  50  to snap back to its original position. 
     Although it is of course highly advantageous for the teeth  43  and stops  33  to be located directly adjacent the tool-receiving portion  41  for efficient transfer of force to the ratchet means, the skilled person will appreciate that other arrangements are possible in which the teeth  43  and stops  33  are located at the end opposite the tool-receiving portion  41 . For example, tooth portion  42  could be in engagement with end portion  60  and the first end  55  of spring  50 . A shaft (for example, a much more elongate version of the boss  72 ) passing through the centre of spring  50  and in engagement with tool-receiving portion  41  would be used to transmit force to the ratchet means. The second end  56  of spring  50  could be fixed with respect to hinge member  11  by any suitable means, for example by providing a sleeve around tool-receiving portion  41 , the sleeve being adapted to receive the second end  56 . 
     It will be appreciated that many other modifications of the specific embodiments described herein are possible without departing from the scope of the present invention, as defined by the claims appended hereto. For example, the roles of the first and second hinge members may be reversed with suitable rearrangement of the internal components. The terminal segments  52  of the spring  50  need not be transverse to the axis of the cylindrical body portion  30  as shown, but may be aligned longitudinally to fit into recesses in end portion  60  and tooth portion  42 . End portion  60  could also be replaced with a second adjustment member to provide additional scope to adjust the spring tension. The number of teeth  43  on tooth portion  42  is not fixed, and indeed may be increased to provide even finer stepped adjustment of the tension, if so desired.

Technology Category: y