Patent Document

CROSS-REFERENCE TO RELATED APPLICATION(S) 
       [0001]    The present non-provisional patent application claims the benefit of priority of GB 1416520.3, which is entitled “FIXING SYSTEM” and having a priority date of Sep. 18, 2014 and which is incorporated in full by reference herein and EP15157164.3, which is entitled “FIXING SYSTEM” and having a priority date of Mar. 2, 2015, and which is incorporated in full by reference herein. 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates to a fixing device and finds particular, although not exclusive, utility in providing an anchoring point in plasterboard cavity walls or ceilings for the purpose of affixing other items thereto. 
       BACKGROUND OF THE INVENTION 
       [0003]    GB2484771 discloses a fixing device for securing into a hole in plasterboard, comprising: a body having an anchor receiving aperture, and a passage that extends within the body, spaced from the anchor receiving aperture; a shaft provided within the passage, the shaft being rotatably movable, independent of axial movement, within the passage; and retaining means coupled to the shaft and configured to be movable between an extended position, in which the fixing device is retainable in said hole, and a retracted position, in which the fixing device is removably insertable into said hole. 
         [0004]    The fixing device may be operated, once it has been inserted into a hole in a structure, by moving the retaining member to the extended position. For instance, a hole may be drilled in a plasterboard structure for insertion of the fixing device axially therein. The fixing device may be inserted into the hole from the front face of the plasterboard, such that the retaining members are behind the rear face of the plasterboard. Rotating the shaft causes the retaining member to move from its retracted position (i.e. its ambush position, in which it sits within the axial profile of the body) to its extended position (in which it projects radially away from the body). In the extended position, the retaining member therefore substantially inhibits movement of the fixing device through the hole in the plasterboard, thus preventing removal of the fixing device from the front face of the structure. If the fixing device is recessed within the hole (either by over-insertion or if the body has a depth less than the thickness of plasterboard), then the retaining member can be drawn tight against the rear face of the plasterboard by fixing a plate (which could be, for instance, part of a hook or bracket for attachment to the plasterboard) to the front face with an anchor, received within the anchor receiving aperture. Specifically, the anchor may draw the plate and the fixing device toward each other, thereby drawing the retaining member tight against the rear face, and drawing the plate tight against the front face. 
         [0005]    Different thicknesses of plasterboard require insertion of this form of fixing device to different depths. However, skill is required in determining this depth and accidental over-insertion of the fixing device, such that the device is lost into a cavity behind the plasterboard, is a common risk. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    According to a first aspect of the present invention, there is provided a fixing device for securing into a hole in plasterboard, the fixing device comprising: a body comprising: an anchor receiving aperture in a first face of the body; and a passage that extends within the body from the first face to a second face opposite the first face, the passage being spaced from the anchor receiving aperture; a shaft provided within the passage and extending from the first face to the second face, the shaft being rotatably movable within the passage; a retaining member coupled to the shaft adjacent to the second face, and configured to be movable between an extended position, in which the fixing device is retainable in said hole, and a retracted position, in which the fixing device is removably insertable into said hole; and at least one over-insertion stop arranged to project away from the body in a direction substantially parallel to the first face such that over-insertion of the body into a hole is prevented; wherein the over-insertion stop is configured to be moveable between a first position adjacent to the first face of the body, and a second position spaced from the first face of the body in a direction away from the second face of the body, such that the body is insertable into a hole to a depth greater than a distance between the first face and the second face. 
         [0007]    In this way, the body of the fixing device may be inserted into a hole in a, for instance plasterboard, wall such that the retaining members may be extended to hold the fixing device in the wall. The over-insertion stops prevent over-insertion of the body into the hole and subsequent loss of the fixing device into a cavity behind the plasterboard. Movement of the over-insertion stops allows the fixing device to be used with a variety of thicknesses of plasterboard wall. 
         [0008]    Specifically, on a plasterboard wall having a thickness greater than the depth of the body, the body may be inserted into a hole up to a depth equal to the depth of the body plus the distance between the first and second positions of the over-insertion stop; however, insertion beyond this depth is prevented, and therefore loss of the fixing device into a cavity behind the plasterboard is prevented. 
         [0009]    In contrast, on a wall having a thickness equal to the depth of the body, the over-insertion stops may be maintained in the first position adjacent to the first face of the body; thus, the retaining members engage with a rear face of the plasterboard, while the over-insertion stops engage with a front face of the plasterboard. If the body is over-inserted into the plasterboard, then movement of the over-insertion stops permits the body to move down into the hole by a distance equal to the depth of the body plus the distance between the first and second positions of the over-insertion stop; however, the over-insertion stops prevent loss of the fixing device into the cavity behind the plasterboard. 
         [0010]    Accordingly, the present invention provides a fixing device that may be used over a range of plasterboard wall thicknesses, but without the risk of the fixing device being lost into a cavity behind the plasterboard. 
         [0011]    The fixing device may further comprise a collar on which the over-insertion stop is provided, the collar configured to slidably receive the body therein. 
         [0012]    In alternative embodiments, the fixing device may comprise a runner, or a plurality of runners, moveable within the body upon which the over-insertion stop is provided. 
         [0013]    The collar may further comprise an interior flange and/or the body may further comprise an exterior flange. The interior and exterior flanges may be arranged to cooperate such that movement of the over-insertion stop beyond the second position is prevented. 
         [0014]    In fact, in all embodiments movement of the over-insertion stop beyond the second position may be prevented. Moreover, movement of the over-insertion stop beyond the first position may be prevented; in particular movement of the over-insertion stop may be limited to between the first and second positions, and various means and mechanisms for achieving this are envisaged. However, in preferred embodiments movement of the over-insertion stop beyond the first position may be permitted, such that the fixing device may be disassembled (for instance by removing the body from the collar) and/or re-assembled. 
         [0015]    The interior of the collar may have a profile that substantially conforms to that of the exterior of the body, such that smooth and/or sliding motion of the collar relative to the body is enabled. In particular the collar and/or the body may comprise corresponding rails and respective grooves to guide relative movement therebetween. 
         [0016]    The fixing device may comprise a single over-insertion stop, which may run around a periphery of the body. Alternatively or additionally, the fixing device may comprise a plurality of over-insertion stops, which may be spaced around a periphery of the body. 
         [0017]    The fixing device may be a single unit, or a kit of individual pieces, comprising: an actuation member (which comprises the shaft coupled to the retaining member, as described above), and the body described above. The fixing device may be suitable for securing into structures other than plasterboard, such as dry-lining, insulated plasterboard, cladding materials, masonry brick and concrete block walls. The fixing device may be suitable for securing loads of up to 45 kg in a vertical wall. The fixing device may be suitable for securing loads of up to 75 kg in a vertical wall. The fixing device may be either releasably securable, such that it may be reused, or non-releasably securable, such that release of the fixing device is only possible via sacrificial damage to one or more of the components of the fixing device. For instance, application of a force on the fixing device of greater than 750N parallel to the axis of the anchor receiving aperture may cause the coupling between the retaining member and the shaft to fail, thereby facilitating release of the fixing device from the structure. 
         [0018]    The body may be substantially circular in cross-section, for convenient insertion into a circular hole drilled into a structure. However, other shapes are contemplated, such as rectangular, square and hexagonal, or other polygonal forms. The body may be substantially cylindrical in order to maximise the surface area of contact with the structure, when inserted into a circular hole, thereby achieving maximum friction between fixing device and structure for preventing relative movement. 
         [0019]    The body may have a diameter between approximately 13 mm and 25 mm. The diameter may be approximately 13 mm, 16 mm, 20 mm or 25 mm. In some embodiments, the diameter of the body on its rear face may be slightly less than the diameter of the body on its front, by for instance 0.2 mm. The depth of the body may match a standard thickness of plasterboard, such as between 9 mm and 18 mm. Preferably, it may be 9.5 mm, 11 mm, 11.5 mm, 12 mm, 12.5 mm, 15 mm or 15.5 mm so that the body will neither be proud of, nor recessed in, the surface of the plasterboard, when in use. However, it is envisaged that a body having a given depth may be used on any thickness of plasterboard, especially if that thickness is greater than the depth of the body. The diameter and depth of the body can be configured to accept different sizes and types of anchor. For instance, a larger anchor may require not only a larger anchor receiving aperture, but also a larger body. 
         [0020]    The body may be formed from a plastics material, preferably by moulding, or from any ferrous and non-ferrous metals, white metal alloys, ceramics, lignocellulosic materials, etc. 
         [0021]    The anchor receiving aperture may be a hole suitable for receiving an anchor therein. The anchor receiving aperture is distinct from the shaft. The anchor receiving aperture may be between 4.5 mm and 6.8 mm in diameter. The anchor receiving aperture may be 4.5 mm, 6.5 mm or 6.8 mm in diameter. The anchor receiving aperture may be threaded, for insertion of a complementary anchor such as a bolt or screw. The thread may be integrally moulded with the body, or may be provided in a threaded insert to the body. A threaded screw could cut into an internal wall of the anchor receiving aperture, thereby producing a complementary internal thread. Alternatively, the anchor receiving aperture may be splined, for ease of manufacture. The splines may project inwardly from the circumference of the anchor receiving aperture a distance of between 1 mm and 1.25 mm. The anchor receiving aperture may comprise multi-pointed splines. The anchor receiving aperture may be located centrally in the body. 
         [0022]    The anchor may be a nail, a screw, a bolt, or similar fastener that is suitable for fastening any item to the fixing device. Alternatively, the anchor may be a forged steel eye bolt or other fastening for further securing a component to it. 
         [0023]    The passage may be manufactured without an internal thread. Accordingly, manufacture is easier, and the cost of production can be decreased. Similarly, the shaft may be manufactured without an external thread. Again, the manufacture of an unthreaded shaft is both easier and cheaper than the manufacture of a threaded shaft. This is especially true when considering the high tolerances involved in the production of complementary threads. Even in the case in which both passage and shaft are threaded, if the threads are not complementary (i.e. if they do not co-operatively engage with one another) assembly of the fixing device is simplified over prior art devices. In particular, the retaining member may be coupled to the shaft before insertion into the passage. Accordingly, damage to the body will not result from the welding process, and excess glue will not bond to the threads of the passage if the coupling is by gluing. 
         [0024]    The passage may be threaded (i.e. it may have a helical groove/ridge provided on its inner surface); however, in a preferred embodiment, the passage is not threaded, for ease of manufacture. The passage may have a smooth bore. The passage may be spaced from the edge of the body by between 0.775 mm and 2.15 mm. The passage may be spaced from the edge of the body by 0.775 mm, 1.15 mm, 1.525 mm or 2.15 mm. The passage may be disposed in a recess in the body. The recess may be in a substantially circular face of the body, for instance the front face. The recess may have a maximum extension inwardly from the circumferential edge of the body of between 4 mm and 7.5 mm. The recess may have a maximum extension inwardly from the circumferential edge of the body of 4.1 mm, 4.5 mm, 5.75 mm or 7.5 mm. In this way, one end of the shaft may remain within the recess so as not to project beyond a surface of the body. The recess may be shaped to form a guide rail in the body, to aid automatic orientation of the casing during automatic assembly. The guide rail may be substantially rectangular in form, and have a width of between 5 mm and 10 mm. The guide rail may have a width of 5.2 mm, 7 mm, 8.5 mm or 10 mm. The passage may pass through the body. The passage may pass from one side of the body to another opposed side. For example, the passage may pass from a substantially circular face of the body to an opposing substantially circular face. The passage may have a circular cross-section, for axial insertion of the shaft therein, which may provide free rotation of the shaft within the passage. The passage may have a diameter of between 2.25 mm and 3.5 mm. The passage may have a diameter of 2.25 mm, 2.75 mm or 3.5 mm. Alternatively, the passage may be open sided, for facilitating radial insertion of the shaft therein. The passage may be a keyhole shape, having a cross-section that is defined by a circle abutting a dovetail shape at its narrowest part. Insertion of the shaft into the passage may be via a press-fit from the wide part of the dovetail, into the circle, via the constriction of the narrow part of the dovetail. A further slot may be provided in the surface of the body, adjacent and having an axis parallel to that of the passage. The slot may enable resilient biasing of the dovetail constriction for insertion of the shaft. The shaft may therefore be maintained within the passage due to a larger diameter of the shaft compared to the width of the dovetail constriction. Free rotation of the shaft within the passage may be provided. In this way, it may be possible to couple the shaft to the retaining member before inserting it into the passage. 
         [0025]    The shaft may have a diameter of 2.2 mm and 3.5 mm. The shaft may have a diameter of 2.2 mm, 2.25 mm, 2.75 mm or 3.5 mm. The shaft may have a diameter less than 0.05 mm less than the diameter of the passage. The shaft may have a length chosen to correspond to the depth of the body. In one embodiment, the shaft may be 13.2 mm long, for a body of depth of 11.5 mm. The shaft may be threaded (i.e. it may have a helical groove/ridge provided on its exterior surface), although not in such a way as to form a complimentary thread to any thread in the passage. However, in a preferred embodiment, the shaft is substantially not threaded (i.e. unthreaded or smooth along at least a substantial part of its length), for ease of manufacture. The shaft may have limiting means for limiting relative axial movement of the shaft within the passage. The limiting means may be a limiting apparatus. The limiting means may substantially inhibit any relative axial movement of the shaft within the passage. Alternatively, the limiting means may permit relative axial movement of the shaft within the passage of up to 1.5 mm, preferably approximately 1.2 mm. The limiting means may be an enlarged head. For instance, at an end of the shaft opposite the retaining member may be located an approximately cylindrical body, co-axial with the shaft and having a diameter larger than that of the shaft. Alternatively, the limiting means may be a non-helical, circumferential, annular or ring-like groove around the shaft provided with a spring-clip or circlip engaged therein. The groove may have a depth of between 0.375 mm and 0.6 mm, preferably 0.375 mm, 0.425 mm or 0.6 mm. The groove may have a depth of approximately 1.2 mm. The groove may be spaced from one end of the shaft by approximately 1.5 mm. The spring-clip or circlip may be manufactured from carbon steel that is phosphate and oil finished. The spring-clip or circlip may be manufactured from stainless steel or beryllium copper. The limiting means may comprise the shaft being at least partially threaded, and a nut received thereon, such as a nyloc nut. The spring-clip, circlip, nut, or other limiting means may be removable from the shaft. 
         [0026]    The shaft may have actuation means for moving the retaining means between the extended position and the retracted position. The actuation means may be an actuator. The actuation means may be a screw drive, for instance a slot, cross, Phillips®, Pozidrive®, hex or similar screw drive. 
         [0027]    The retaining member may be movable between the retracted position and the extended position by axial rotation of the shaft within the passage. 
         [0028]    The retaining member may be rigidly coupled to one end of the shaft, such as by welding or gluing; however, welding is preferred due to the increased strength provided. The retaining member may comprise a hole for receiving the shaft, and the shaft may comprise a flange against which the retaining member can be abutted for rigid coupling. The hole may have a diameter the same as the diameter of the shaft. The flange may have a diameter of between 3.5 mm and 6 mm. The flange may have a diameter of approximately 3.5 mm, 5 mm or 6 mm. The flange may have a thickness of 1 mm. The shaft may comprise knurling adjacent the flange, to improve frictional contact between the shaft and the retaining member. The hole of the retaining member and the flange of the shaft arrangement may be configured to be countersunk; i.e. the hole may be shaped to receive the flange therein, such that the shaft does not project behind the retaining member. In one embodiment, the flange is configured in the shape of a truncated cone, and the hole has a corresponding profile for contact with the curved surface of the flange. 
         [0029]    The retaining member may be referred to as retaining means. 
         [0030]    In another embodiment, the retaining means may comprise a planar portion and a tongue that projects away from the planar portion. The tongue may be arranged to engage with a corresponding socket in the flange, when the shaft is received within the hole in the retaining means. Engagement of the tongue and socket may substantially prevent relative rotation of the shaft and retaining means, about the axis of the shaft. The tongue may hold the shaft in precisely one orientation with respect to the retaining means. The tongue and socket may have corresponding profiles. The tongue and socket may engage in a close fit. The tongue may be formed by pressing out a portion of the retaining means. The tongue may be formed by cutting a profile (for instance a partial rectangular profile) in the retaining means and folding the part inside the profile out of the plane of the retaining means. Such an arrangement obviates the need for welding, riveting or gluing the retaining means to a shaft, and enables a much simpler method of manufacture and product assembly. 
         [0031]    The retaining means and the shaft may be manufactured from stainless steel. The retaining means and the shaft may be manufactured from carbon steel and electroplated to prevent corrosion. 
         [0032]    The retaining means may be a retaining member. The retaining means may be an arm. The arm may be of any shape or profile; however, in a preferred embodiment the retaining means is a substantially flat arm. The flat arm may have a thickness of 1.2 mm. The flat arm may be configured to have a thickness in the direction of the axis of the shaft significantly smaller than its dimensions radially from the axis of the shaft. The arm may be sized and/or configured for cutting into thermal insulation (e.g. polystyrene) behind plasterboard, such as by having sharp edges. 
         [0033]    The fixing device&#39;s operation is not impaired by the presence of a vapour barrier plastic sheeting, or fibrous or semi-rigid insulation in the cavity walls. The flat nature of the arms permits deployment to engage in a narrow cavity less than 1.6 mm wide, and permits the cutting of its own recess in plasterboard, if necessary. 
         [0034]    The arm may have a surface area, for contact with a planar surface, of between approximately a third of the axial cross-sectional area of the body of the fixing device and approximately equal to the cross-sectional area of the body of the fixing device. The arm may have a surface area, for contact with a planar surface, approximately a half of the cross-sectional area of the body of the fixing device. 
         [0035]    The arm may have a surface area for contact with a planar surface of between 40 mm 2  and 500 mm 2 , and a thickness of between 0.8 mm and 1.2 mm. 
         [0036]    The fixing device may further be provided with a cap that covers the shaft, to prevent tampering therewith after the fixing device has been secured into a structure. The cap may be receivable within the anchor receiving aperture. 
         [0037]    The body may have only one passage. Alternatively, the body may have more than one passage and the fixing device may have: a shaft provided within each or only some of the passages. The shafts may be rotatably movable, independent of axial movement, within their respective passages. The retaining means may be coupled to each shaft and may be configured to be movable between a respective extended position, in which the device is retainable in a hole, and a respective retracted position, in which the fixing device is removably insertable into said hole. 
         [0038]    The plurality of passages may be disposed substantially rotationally symmetrically about the anchor receiving aperture, and each passage may have a respective passage axis that is arranged to be parallel to the aperture axis. 
         [0039]    The or each shaft may be rotatably movable, independent of axial movement, within the respective passage. 
         [0040]    Each retaining means may be a substantially flat arm having a surface area, for contact with a planar surface, equal to that of each other arm, and the total surface area, for contact with a flat surface, of all the arms may be approximately equal to the cross-sectional area of the body of the fixing device. 
         [0041]    Each retaining means may be a substantially flat arm, and one arm may have a surface area, for contact with a planar surface, different to that of another arm, and the total surface area, for contact with a flat surface, of all the arms may be greater than the cross-sectional area of the body of the fixing device. Thus, in the retracted position, the substantially flat arms may overlap one another, but in the extended position, the fixing device may be secured more effectively, by spreading any applied load over a larger surface area than if both arms had the same surface area. Furthermore, one of the substantially flat arms may be further configured to be movable into and out of a plane coincident with another of the substantially flat arms. That is, one of the flat arms may lie substantially in a first plane, and another of the flat arms may be movable between a first location, in which it lies substantially in the first plane, and a second location, in which it lies substantially in a second plane, parallel to the first plane. In this way, the fixing device may be secured evenly, so as to prevent a load exerting a twisting force on the fixing device. For instance, in order to secure the device in a hole in a wall, the first shaft may be rotated in order to move the first flat arm from its retracted position into its extended position, then the second shaft may be moved axially to move the second flat arm into the same plane as the first flat arm, and finally the second shaft may be rotated to move the second flat arm from its retracted position into its extended position. Similarly, in order to remove the device from the hole in the wall, the reverse operation may be performed, i.e. the second shaft may be rotated to move the second flat arm from its extended position into its retracted position, the second shaft may then be moved axially to move the second flat arm out of the plane of the first flat arm, and finally the first shaft may be rotated in order to move the first flat arm from its extended position into its retracted position. 
         [0042]    If there is more than one passage, then each one may be provided symmetrically around the body. In this way, the fixing device may be secured, in use, evenly about an axis defined by the anchor receiving aperture. However, the shafts may be provided in other configurations to suit specific needs, such as when the fixing device is in a corner or against another object, which may prevent the arms being rotated at least at one point. Each respective retaining means may have a surface area for contact with a flat surface substantially equal to the cross-sectional area of the body of the fixing device divided by the number of respective retaining means. The fixing device may further comprise a stop, for maintaining the retaining means in an optimal extended position. In this way, optimal securing of the fixing device may be achieved without an operator of the fixing device having to apply a judgment as to how much to move the retaining means in order to secure the fixing device. The optimal extended position may be the position in which maximum securing is provided by the locking arm. The stop may be a projection. The projection may be integrally formed with the body. The stop may have a diameter of between 1.3 mm and 2 mm. The stop may have a diameter of approximately 1.3 mm, 1.5 mm or 1.2 mm. The stop may have a depth of 1 mm. The stop may be located adjacent the circumferential edge of the rear of the body. 
         [0043]    The fixing device may further comprise anti-rotation means/part for preventing rotation of the fixing device about an axis parallel to that of the anchor receiving aperture. In this way, insertion of an anchor into the anchor receiving aperture may be made easier, in that the fixing device may not rotate as an anchor is rotatably driven therein. The anti-rotation means may be anti-rotation apparatus. The anti-rotation means may comprise any number of wings parallel to the anchor axis. For instance, the anti-rotation means may be a single wing parallel to the axis of the anchor receiving aperture. The anti-rotation means may be a pair of wings parallel to the axis of the anchor receiving aperture, and located diametrically opposite one another. The wings may extend radially away from the outer surface of the body to thus create friction with the surface of the structure into which the device is placed so as to prohibit or, at least reduce, rotation of the device relative to the structure. The wings may cut into the structure around the hole on insertion of the fixing device into that hole. The wings may extend radially away from the outer surface of the body a distance of approximately 3 mm. The wings may have a thickness of between 1 mm and 1.5 mm. The wings may have a thickness of approximately 1 mm, 1.2 mm or 1.5 mm. The wings may have a depth equal to the depth of the body. 
         [0044]    The over-insertion stops may be formed with the anti-rotation parts. 
         [0045]    The fixing device may further comprise a cap that covers the shaft(s), to prevent tampering with the shaft(s) after the fixing device has been secured to a structure. The cap may be secured with an anchor into the anchor receiving aperture. 
         [0046]    According to one embodiment of the invention, the fixing device may be assembled by: providing a body having an anchor receiving aperture and a passage that extends within the body, spaced from the anchor receiving aperture, and a shaft having an enlarged head; inserting the shaft through the passage; and coupling a retaining means to the shaft. 
         [0047]    According to one embodiment of the invention, the fixing device may be assembled by: providing a body having an anchor receiving aperture and a passage that extends within the body, spaced from the anchor receiving aperture, and a shaft having a circumferential groove; coupling a retaining means to the shaft; inserting the shafts through the passage; and providing a circlip on the circumferential groove. 
         [0048]    According to one embodiment of the invention, the fixing device may be assembled by: providing a body having an anchor receiving aperture and a passage that extends within the body, spaced from the anchor receiving aperture, and a shaft having an enlarged head; coupling a retaining means to the shaft; and inserting the shafts into the passage radially through an open side thereof. 
         [0049]    According to a second aspect of the present invention, there is provided a fixing system including the fixing device of the first aspect, the fixing system for securing the fixing device into a hole in plasterboard, wherein: the anchor receiving aperture of the body has an aperture axis; the body comprises: a plurality of passages, each extending within the body, spaced from the anchor receiving aperture; a respective shaft provided within each passage, each shaft being rotatably movable within the respective passage; and a respective retaining member coupled to each shaft, each retaining member configured to be pivotally movable about the respective shaft between an extended position, in which the fixing device is retainable in said hole, and a retracted position, in which the fixing device is removably insertable into said hole; and the fixing system comprises an activation tool, comprising an activation member arrangable such that rotation of the activation tool about an activation axis causes each retaining member to move from the retracted position to the extended position substantially simultaneously. 
         [0050]    In this way, uneven gripping and/or slippage of the fixing device can be avoided by reducing the steps taken to secure the device. 
         [0051]    The fixing device may be operated, once it has been inserted into a hole in a structure, by moving the retaining members to the extended position. For instance, a hole may be drilled in a plasterboard structure for insertion of the fixing device axially therein. The fixing device may be inserted into the hole from the front face of the plasterboard, such that the retaining members are behind the rear face of the plasterboard. Rotating the activation tool causes the retaining members to move from their retracted position (i.e. their ambush position, in which they sit within the axial profile of the body) to their extended position (in which they project radially away from the body). In the extended position, the retaining members therefore substantially inhibit movement of the fixing device through the hole in the plasterboard, thus preventing removal of the fixing device from the front face of the structure. If the fixing device is recessed within the hole (either by over-insertion or if the body has a depth less than the thickness of plasterboard), then the retaining members can be drawn tight against the rear face of the plasterboard by fixing a plate (which could be, for instance, part of a hook or bracket for attachment to the plasterboard) to the front face with an anchor, received within the anchor receiving aperture. Specifically, the anchor may draw the plate and the fixing device toward each other, thereby drawing the retaining members tight against the rear face, and drawing the plate tight against the front face. 
         [0052]    In particular, the activation member may be arrangable such that rotation of the activation tool about the activation axis causes the activation member to contact each retaining member to push each retaining member from the retracted position to the extended position. 
         [0053]    The activation member may be a rod, a plate and/or substantially flat. The activation member may comprise a substantially rectangular shape. The activation member may be stainless steel, and may be coloured to match a fixing device with which it is to be used. 
         [0054]    The activation tool may further comprise a shaft connected to the activation member, the shaft configured to be removably insertable into the anchor receiving aperture. 
         [0055]    The body may further comprise a slot therein, the slot arranged within the body so as to include the aperture axis, and the slot configured such that the activation member is removably insertable therethrough. In this way, the shaft and activation member may be inserted together through the aperture and slot, respectively. The shaft may be of a sufficient length for the activation member to pass through the slot and out of a rear side of the body from the front side. In this way, the activation member may be rotatable on the rear side of the body, when a user rotates the shaft on the front side of the body. 
         [0056]    The activation tool may further comprise a stop located on the shaft, and the stop may be arranged such that a distance along the shaft between the stop and the activation member is substantially equal to a thickness of the body along the aperture axis. In this way, over-insertion of the shaft into the body may be prevented. The stop may be in the form of a handle for manual manipulation of the tool. 
         [0057]    Alternatively, the activation member may be rotatably coupled to the body, and may comprise a socket for receiving an end of a hand tool therein for rotation of the activation member about the activation axis. For instance, the socket may be a screw-drive, such that a corresponding screw driver may be inserted through the aperture to engage with the activation member. The screw driver may be removed subsequent to actuation of the retaining members, leaving the activation member behind the body. 
         [0058]    The activation member may be releasably attachable to the body, for instance frangibly attached, such that actuation by the hand tool causes the activation member to decouple. In such arrangements, actuation of the retaining arms is followed by loss of the activation member into a cavity in the wall/ceiling in which the device is fixed. Alternatively, the activation member may be permanently attached, for instance rotationally attached, such that no loss of the activation member accompanies actuation of the retaining members. 
         [0059]    The activation axis may be coaxial with the aperture axis. The radial length of the activation member may be greater than substantially equal to a radial distance of a rotation axis of the retaining member from the aperture axis. 
         [0060]    According to a third aspect of the present invention, there is provided a fixing system for securing a fixing device into a hole in plasterboard, the fixing system comprising: a body having an anchor receiving aperture therein, the anchor receiving aperture having an aperture axis; a plurality of passages, each extending within the body, spaced from the anchor receiving aperture; a respective shaft provided within each passage, each shaft being rotatably movable within the passage; a respective retaining member coupled to each shaft, each retaining member configured to be pivotally movable about the respective shaft between an extended position, in which the fixing device is retainable in said hole, and a retracted position, in which the fixing device is removably insertable into said hole; and an activation tool, comprising an activation member arrangable such that rotation of the activation tool about an activation axis causes each retaining member to move from the retracted position to the extended position substantially simultaneously. 
         [0061]    According to a fourth aspect of the present invention, there is provided a fixing device for securing into a hole in plasterboard, and for use with an activation tool, the fixing device comprising: a body having an anchor receiving aperture therein, the anchor receiving aperture having an aperture axis; a plurality of passages, each extending within the body, spaced from the anchor receiving aperture; a respective shaft provided within each passage, each shaft being rotatably movable within the passage; a respective retaining member coupled to each shaft, each retaining member configured to be pivotally movable about the respective shaft between an extended position, in which the fixing device is retainable in said hole, and a retracted position, in which the fixing device is removably insertable into said hole; and a slot arranged within the body so as to include the aperture axis, and the slot configured such that the activation member is removably insertable therethrough; wherein the activation tool comprises an activation member arrangable such that rotation of the activation tool about an activation axis causes each retaining member to move from the retracted position to the extended position substantially simultaneously. 
         [0062]    According to a fifth aspect of the present invention, there is provided an activation tool for use in a fixing system for securing a fixing device according to the second aspect into a hole in plasterboard, the activation tool comprising: a shaft configured to be removably insertable into the anchor receiving aperture of the fixing device; an activation member connected to the shaft, the activation member configured to removably insertable into the slot of the fixing device, and arrangable such that rotation of the activation tool about an activation axis causes each retaining member of the fixing device to move from the retracted position to the extended position substantially simultaneously. 
         [0063]    According to a sixth aspect of the present invention, there is provided a method of securing a fixing device into a hole in plasterboard, the method comprising the steps of: providing a fixing device according to the first aspect; inserting the fixing device into a hole in a surface, such that the retaining members are placed behind a rear face of the surface; and moving the retaining member from their retracted position to their extended position. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0064]    The above and other characteristics, features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. This description is given for the sake of example only, without limiting the scope of the invention. The reference figures quoted below refer to the attached drawings. 
           [0065]      FIG. 1  is a perspective view of a known fixing device. 
           [0066]      FIG. 2  is a perspective view of a component part of a fixing device according to the invention. 
           [0067]      FIG. 3  is a perspective view of a further component part of the fixing device of  FIG. 2 . 
           [0068]      FIG. 4  is a cross-sectional view of a partially assembled fixing device of  FIGS. 2 and 3 . 
           [0069]      FIG. 5  is an exploded perspective view of a further fixing device according to the invention. 
           [0070]      FIG. 6  is a perspective view of the fixing device of  FIG. 5  in an assembled state. 
           [0071]      FIG. 7  is a front view of a fixing device incorporating various optional features. 
           [0072]      FIG. 8  is a rear view of the fixing device of  FIG. 7 . 
           [0073]      FIG. 9  is a cross-sectional view of the fixing device of  FIG. 7 . 
           [0074]      FIG. 10  is another rear view of the fixing device of  FIG. 7 . 
           [0075]      FIG. 11  is another cross-sectional view of the fixing device of  FIG. 7 . 
           [0076]      FIG. 12  is a perspective view of a component of the fixing device of  FIG. 7 . 
           [0077]      FIG. 13  is an axial view of another component of the fixing device of  FIG. 7 . 
           [0078]      FIG. 14  is a front view of another fixing device incorporating various optional features. 
           [0079]      FIG. 15  is a rear view of the fixing device of  FIG. 14 . 
           [0080]      FIG. 16  is a cross-sectional view of the fixing device of  FIG. 14 . 
           [0081]      FIG. 17  is another rear view of the fixing device of  FIG. 14 . 
           [0082]      FIG. 18  is a cross-sectional view of a still further fixing device incorporating various optional features. 
           [0083]      FIG. 19  is rear view of the fixing device of  FIG. 18 . 
           [0084]      FIG. 20  is a front view of the fixing device of  FIG. 18 . 
           [0085]      FIG. 21  is another rear view of the fixing device of  FIG. 18 . 
           [0086]      FIG. 22  is a front view of a component of a yet further fixing device incorporating various optional features. 
           [0087]      FIG. 23  is a cross-sectional view of a fixing device incorporating the component of  FIG. 22 . 
           [0088]      FIG. 24  is a rear view of the fixing device of  FIG. 23 . 
           [0089]      FIG. 25  is another rear view of the fixing device of  FIG. 23 . 
           [0090]      FIG. 26  is a cross-sectional view of a fixing device incorporating various optional features. 
           [0091]      FIG. 27  is a perspective view of a component of the fixing device of  FIG. 26 . 
           [0092]      FIG. 28  is a perspective view of the fixing device of  FIG. 26 . 
           [0093]      FIG. 29  is a perspective view of a tool. 
           [0094]      FIG. 30  is a front view of a fixing device incorporating various optional features. 
           [0095]      FIG. 31  is a cross-sectional view of the fixing device of  FIG. 30 . 
           [0096]      FIG. 32  is a rear view of the fixing device of  FIG. 30 . 
           [0097]      FIG. 33  is another rear view of the fixing device of  FIG. 30 . 
           [0098]      FIG. 34  is a rear view of an arm. 
           [0099]      FIG. 35  is a rear view of an arm and shaft arrangement. 
           [0100]      FIG. 36  is a cross-sectional view of the arrangement of  FIG. 35 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0101]    The present invention will be described with respect to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. Each drawing may not include all of the features of the invention and therefore should not necessarily be considered to be an embodiment of the invention. In the drawings, the size of some of the elements may be exaggerated and not drawn to scale for illustrative purposes. The dimensions and the relative dimensions do not correspond to actual reductions to practice of the invention. 
         [0102]    Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that operation is capable in other sequences than described or illustrated herein. 
         [0103]    Moreover, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that operation is capable in other orientations than described or illustrated herein. 
         [0104]    It is to be noticed that the term “comprising”, used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression “a device comprising means A and B” should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B. 
         [0105]    Reference throughout this specification to “an embodiment” or “an aspect” means that a particular feature, structure or characteristic described in connection with the embodiment or aspect is included in at least one embodiment or aspect of the present invention. Thus, appearances of the phrases “in one embodiment”, “in an embodiment”, or “in an aspect” in various places throughout this specification are not necessarily all referring to the same embodiment or aspect, but may refer to different embodiments or aspects. Furthermore, the particular features, structures or characteristics of any embodiment or aspect of the invention may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments or aspects. 
         [0106]    Similarly, it should be appreciated that in the description various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Moreover, the description of any individual drawing or aspect should not necessarily be considered to be an embodiment of the invention. Rather, as the following claims reflect, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention. 
         [0107]    Furthermore, while some embodiments described herein include some features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form yet further embodiments, as will be understood by those skilled in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination. 
         [0108]    In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practised without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description. 
         [0109]    In the discussion of the invention, unless stated to the contrary, the disclosure of alternative values for the upper or lower limit of the permitted range of a parameter, coupled with an indication that one of said values is more highly preferred than the other, is to be construed as an implied statement that each intermediate value of said parameter, lying between the more preferred and the less preferred of said alternatives, is itself preferred to said less preferred value and also to each value lying between said less preferred value and said intermediate value. 
         [0110]    The use of the term “at least one” may mean only one in certain circumstances. 
         [0111]    The principles of the invention will now be described by a detailed description of at least one drawing relating to exemplary features of the invention. It is clear that other arrangements can be configured according to the knowledge of persons skilled in the art without departing from the underlying concept or technical teaching of the invention, the invention being limited only by the terms of the appended claims. 
         [0112]      FIG. 1  is a perspective view of a known fixing device having a body  1001  of a substantially cylindrical form, with an axial depth of approximately 11.5 mm and a diameter of approximately 20 mm. The body  1001  has an anchor receiving aperture  1003 , which passes axially through the body  1001 , is internally threaded, and has a diameter of approximately 6.5 mm. The body includes two passages that extend through the body  1001 , each passage having an axis parallel to, and spaced from, the axis of the anchor receiving aperture  1003 . The two passages are disposed diametrically opposite one another around the body  1001 , and set in from the edge of the body  1001 . Each passage has an open-sided keyhole-shaped cross-section, and includes a constriction for retaining a  1005   a ,  1005   b  within the circular portion of the keyhole shape. Either side of each passage are provided slots  1047   a ,  1047   c  and  1047   b ,  1047   d , respectively, each projecting semi-radially inward from the outer surface of the body  1001  and running parallel to the axis of the passages. The body  1001  is also provided with two wings  1015   a ,  1015   b  diametrically opposed around the circumference of the body  1001 , and offset from the passages. 
         [0113]      FIG. 2  is a perspective view of a body  2001  of a fixing device according to the invention, having a substantially cylindrical form. The body  2001  is provided with an anchor receiving aperture  2003  centrally located therein, and a slot  2004  located across a diameter of the aperture  2003  and extending into the body  2001  in diametrically opposite directions. The slot  2004  is of uniform width (although a variable width is also possible) and extends through the entire depth of the body  2001  (i.e. axially from one substantially cylindrical face to another). The body  2001  is also provided with two passages  2037   a ,  2037   b  that extend through the body  2001 , each passage having an axis parallel to, and spaced from, the axis of the anchor receiving aperture  2003 . The passages  2037   a ,  2037   b  are disposed diametrically opposite one another around the body  2001 , are set in from the edge of the body  2001 , are offset from the slot  2004  and are substantially circular in cross-section. The passages  2037   a ,  2037   b  are disposed within respective recesses  2007   a ,  2007   b  in a surface  2009  of the body  2001 . The recesses  2007   a ,  2007   b  are substantially rectangular in form and are of uniform depth. The portion of the surface  2009  remaining forms an approximately H-shaped guide rail. A peripheral flange  2010  runs around a perimeter of the surface  2009 , and is split into four sections by the recesses  2007   a ,  2007   b  and vertical grooves  2020 . 
         [0114]      FIG. 3  is a perspective view of a collar  2050  for use with the body  2001 . The collar  2050  is configured to receive the body  2001  snugly therein, such that rails  2060  engage with the grooves  2020 . An internal flange  2070  is shown which prevents passage of the body  2001  all the way through the collar  2050  when inserted from the top. 
         [0115]    The collar  2050  is also provided with four wings  2015  for preventing rotation of the fixing device about the axis of the anchor receiving aperture  2003 . The wings  2015  are substantially trapezoidal and project radially outward from the surface of the collar  2050 , parallel to the axis of the body  2050 . The wings  2015  are spaced equally around the exterior surface collar  2050 , offset by 45 degrees from the passages  2037   a ,  2037   b.    
         [0116]    Along the top of the wings  2015  is provided an over-insertion stop  2080  in the form of an exterior flange on the collar. 
         [0117]      FIG. 4  is a cross-sectional view showing the body  2001  inserted fully into the collar  2050 ; other parts of the fixing device such as the shaft and retaining members are not shown for clarity. 
         [0118]      FIG. 5  is an exploded perspective view of a further fixing device according to the invention including a body  3001 , collar  3050 , retaining members  3019 , and an activation member  3031 ; other parts of the fixing device such as the shaft are not shown for clarity. The body comprises a surface  3009 , passages  3037  in recesses  3007 , a peripheral flange  3010 , and vertical grooves  3020  substantially the same as in the arrangement shown in  FIG. 2 . The central hole  3002  is of a larger diameter than the anchor receiving aperture  2003 , as it is configured to accommodate the activation member  3031  therein. The activation member  3031  includes the anchor receiving aperture  3003  and the slot  3004 , as well as a bar  3080  disposed on a lower flange  3090 . 
         [0119]    The collar  3050  includes the same features of rails  3060 , an internal flange  3070 , wings  3015  and over-insertion stop  3080 ; however, in this arrangement, the over-insertion stop  3080  is split into four portions, each capping the top of one of the wings  3015 . 
         [0120]    When the slot  3004  is engaged with a tool (for instance a flat head screw driver), the whole of the activation member  3031  may be rotated, such that the bar  3080  rotates, pushing the retaining members  3019  out from their retracted position to their deployed position. Axial motion of the activation member  3031  is prevented by the flange  3090  preventing passage up through the hole  3002 , and is prevented by the retaining members  3019  preventing passage down through the hole  3002 . 
         [0121]      FIG. 6  is a perspective view of the fixing device of  FIG. 5  in an assembled state, with the body  3001  in a fully retracted position within the collar  3050 . 
         [0122]      FIG. 7  shows a fixing device, comprising a body  1  of a substantially cylindrical form, having an axial depth of approximately 11.5 mm and a diameter of approximately 20 mm. The body includes an anchor receiving aperture  3 , which passes axially through the body, is internally threaded, and has a diameter of approximately 6.5 mm. A slot  4  is located across a diameter of the aperture  3 , and extends into the body  1  in diametrically opposite directions. The slot  4  is of uniform width (although a variable width is also possible) and extends through the entire depth of the body (i.e. axially from one substantially cylindrical face to another). The body also includes shafts  5   a ,  5   b , of a substantially rod-like shape, further described with reference to  FIG. 6 , below. The shafts  5   a ,  5   b  are provided within respective passages  37   a ,  37   b  (not shown in  FIG. 1 ), which extend through the body  1 , each passage having an axis parallel to, and spaced from, the axis of the anchor receiving aperture  3 . The passages  37   a ,  37   b  are disposed diametrically opposite one another around the body  1 , set in from the edge of the body  1 , and are substantially circular in cross-section. The passages  37   a ,  37   b  are internally smooth. The passages  37   a ,  37   b  are disposed within respective recesses  7   a ,  7   b  in a surface  9  of the body  1 . The recesses  7   a ,  7   b  are in the form of circular segments in the surface  9 , of uniform depth, with their respective chords being parallel to one another. The portion of the surface  9  remaining forms an approximately rectangular shaped guide rail. Spring-clips  11   a ,  11   b  (shown in detail in  FIG. 7 ) are provided around the shafts  5   a ,  5   b , respectively, to limit axial movement of the shafts  5   a ,  5   b . The spring-clips  11   a ,  11   b  are provided on respective circumferential grooves  39   a ,  39   b  (not shown in this figure) about one end of each shaft  5   a ,  5   b , which limit axial movement of each shaft  5   a ,  5   b  within the passages  37   a ,  37   b . The shafts  5   a ,  5   b  have respective slot screw drives  13   a ,  13   b , in respective ends, for receiving a slot screw driver for rotating the shafts  5   a ,  5   b . The body  1  is also provided with wings  15   a ,  15   b  for preventing rotation of the body  1  about the axis of the anchor receiving aperture  3 . The wings  15   a ,  15   b  are substantially trapezoidal and project radially outward from the surface of the body  1 , parallel to the axis of the body  1 . The wings  15   a ,  15   b  are disposed diametrically opposite one another around the exterior surface body  1 , offset by 90 degrees from the passages  37   a ,  37   b.    
         [0123]      FIG. 8  shows the fixing device of  FIG. 7  from the reverse side. Flanges  17   a ,  17   b , in the form of circular discs coupled to the end of the shafts  5   a ,  5   b  opposing the screw drives, are welded to respective arms  19   a ,  19   b , which are shown in the retracted position in which they sit within the axial profile of the body. The arms  19   a ,  19   b  are flat plates of a substantially semi-circular profile, in one corner of each is a hole through which the respective shaft  5   a ,  5   b  is passed such that the respective flange  17   a ,  17   b  abuts the side of the arm  19   a ,  19   b  opposite the distal end of the shaft  5   a ,  5   b . Rotation of a shaft  5   a ,  5   b  causes rotational movement of the respective arm  19   a ,  19   b  in the plane of  FIG. 2 , which is limited by a respective stop  21   a ,  21   b  in the clockwise direction and another respective stop  21   b ,  21   a  in the anti-clockwise direction. The stops  21   a ,  21   b  are integrally formed with the body  1 , and project beyond the rear circular face of the body, into the plane occupied by the arms  19   a ,  19   b.    
         [0124]      FIG. 9  shows a cross-section of the fixing device along line A-A of  FIGS. 7 and 8 , when inserted into a wall. The arms  19   a ,  19   b  are shown in their retracted position. The wings  15   a ,  15   b  have cut into plasterboard  23 , which is bonded to masonry wall  25  with adhesive  27 , to form a cavity  28 . The cavity  28  may vary in thickness between 10 mm and 25 mm, depending on the thickness of the adhesive  27  at the time the plasterboard  23  was placed in position against the wall  25 . An activation tool  29  is shown inserted into the aperture  3  and slot  4 . Aperture  3  is shown with an internal screw thread  33 . The activation tool  29  comprises an activation member  31 , which is passed through the slot  4  (and out the other side), a shaft  34 , which is passed into the aperture  3 , and a handle  35  for manipulation by a user. The length of the shaft  34  is substantially equal to the thickness of the body  1 , and the handle  35  has a lateral extent (for instance, a diameter in embodiments where it is substantially cylindrical) greater than the diameter of the aperture  3 . In this way, the tool  29  cannot be over inserted and, when inserted fully, the activation member  31  is correctly located to engage with the arms  19   a ,  19   b.    
         [0125]      FIG. 10  shows the same view of the fixing device as  FIG. 8 , but with the arms  19   a ,  19   b  having been pushed into the optimal extended position by the activation tool  29  (indicated in the figure). Thus, the arms  19   a ,  19   b  project radially away from the body  1 , in order to maximise a surface area for contact with the rear of the plasterboard  23 , and abut stops  21   a ,  21   b  respectively. 
         [0126]      FIG. 11  shows a cross-section of the fixing device along line B-B of  FIG. 4 , when inserted into a wall. The arms  19   a ,  19   b  are in their extended position. Shaft  5   a  is provided within passage  37   a . The shaft  5   a  in knurled adjacent the flange  17   a  to improve contact with the arm  19   a.    
         [0127]      FIG. 12  shows a perspective view of an actuation member in accordance with the fixing device shown in  FIGS. 7 to 11  that comprises the shaft  5   a , having a circumferential groove  39   a  for receiving the spring-clip  11   a  and the slot screw drive  13   a , and the arm  19   a  coupled thereto, as described above. 
         [0128]    The shafts  5   a ,  5   b  can be individually rotated, using the slot screw drives  13   a ,  13   b , in order to move their respective arm  19   a ,  19   b  between the retracted position and the extended position. 
         [0129]      FIG. 13  shows the spring-clip  11   a  in accordance with the fixing device shown in  FIGS. 7 to 12 . 
         [0130]      FIG. 14  shows another fixing device, comprising a body  101 , similar to the body  1  of  FIG. 7 , and an anchor receiving aperture  103 , substantially the same as the anchor receiving aperture  3 . However, three slots  104  are provided tangentially to the aperture  103 . Although radial arrangement of the slots  104  is preferred, the tangential arrangement is shown as an example of an alternative; further intermediate arrangements are also considered useful in some embodiments. The fixing device comprises three shafts  105   a ,  105   b ,  105   c , each substantially the same as the shafts  5   a ,  5   b , provided within respective passages  137   a ,  137   b ,  137   c , each substantially the same as the passages  37   a ,  37   b , and disposed rotationally symmetrically around the axis of the body  101 . The passages  137   a ,  137   b ,  137   c  are disposed within respective recesses  107   a ,  107   b ,  107   c  in a surface  109  of the body  1 . The recesses  107   a ,  107   b ,  107   c  are in the form of a rectangular hollow in the surface  9 , of uniform depth, each centred on its respective passage  137   a ,  137   b ,  137   c . Spring-clips  111   a ,  111   b ,  111   c , substantially identical to the spring-clips  11   a ,  11   b , are provided around the shafts  105   a ,  105   b ,  105   c  to limit axial movement of the shafts  105   a ,  105   b ,  105   c . The shafts  105   a ,  105   b ,  105   c  each have slot screw drives  113   a ,  113   b ,  113   c  respectively, substantially the same as the slot screw drives  13   a ,  13   b . The body  101  is also provided with three wings  115   a ,  115   b ,  115   c , substantially the same as the wings  15   a ,  15   b , for preventing rotation of the body  101  about the axis of the anchor receiving aperture  103 . The wings  115   a ,  115   b ,  115   c  are disposed symmetrically around the exterior surface of the body  101 , offset from the passages  137   a ,  137   b ,  137   c.    
         [0131]      FIG. 15  shows the fixing device of  FIG. 14  from the reverse side. Flanges  117   a ,  117   b ,  117   c , substantially the same as the flanges  17   a ,  17   b  , provided on each of the shaft  105   a ,  105   b ,  105   c  are welded to the arms  119   a ,  119   b ,  119   c , respectively, which are shown in the retracted position. Rotational movement of one arm  119   a  in the plane of  FIG. 15  is limited by a stop  121   a  in the clockwise direction and another arm  119   b  in the anti-clockwise direction. The same limits on rotational movement of the other arms  119   b ,  199   c  apply mutatis mutandis. 
         [0132]      FIG. 16  shows a cross-section of the fixing device along line C-C of  FIGS. 14 and 15 , when inserted into a wall, and with a tool  129  in place therein, the tool  129  having three arms for use in the three slots  104 , but being otherwise similar to the tool  29 . The arms  119   a ,  119   b ,  119   c  are in their extended position. The wings  115   a ,  115   b ,  115   c  have cut into plasterboard  123 , which is bonded to masonry wall  125  with adhesive  127 , to form a cavity  128 . The cavity  128  may vary in thickness between 10 mm and 25 mm, depending on the thickness of the adhesive  127  at the time the plasterboard  123  was placed in position against the wall  125 . The shaft  105   a  is provided within passage  137   a  and has a circumferential groove  139   a  provided with spring-clip  111   a , which limits axial movement of the shaft  105   a  within the passage  137   a.    
         [0133]      FIG. 17  shows the same view of the fixing device as  FIG. 15 , but with the arms  119   a ,  119   b ,  119   c  shown having been pushed into the optimal extended position, abutting their respective stops  121   a ,  121   b ,  121   c , by the tool  129 . 
         [0134]      FIG. 18  shows a cross-section of a fixing device. The body  201  is substantially cylindrical in form, having an axial depth of approximately 11.5 mm and a diameter of approximately 20 mm, and has an anchor receiving aperture  203 , similar to the anchor receiving aperture  3  but with a diameter of approximately 4.5 mm, and two passages  237   a ,  237   b , substantially the same as the passages  37   a ,  37   b . The two passages  237   a ,  237   b  are disposed diametrically opposite one another around the body  201 , set in from the edge of the body  201  and are provided within respective recesses in the top surface  9 . The recesses  207   a ,  207   b  are each centred on their respective passage  237   a ,  237   b , and each comprises a central sub recess and an extended top recess. Each central sub recess is in the form of a rectangular hollow in the surface  9 , of uniform depth. Each extended top recess is in the form of circular segment in the surface  9 , of uniform depth less than the depth of the central sub recess, with their respective chords being parallel to one another. The portion of the surface  9  remaining forms an approximately ‘H’ shaped guide rail. Disposed within each passage  237   a ,  237   b  is a respective shaft  205   a ,  205   b , substantially the same as the shafts  5   a ,  5   b , each having a circumferential groove (not shown), provided with a spring-clip  211   a ,  211   b . At the top of each shaft  205   a ,  205   b  is a respective slot screw drive  213   a ,  213   b , substantially the same as the screw drives  13   a ,  13   b , and at the bottom of each shaft is a respective flange  217   a ,  217   b  in the form of a countersunk head (i.e. a conical portion, flaring out from the main portion of the shaft  205   a ,  205   b ). Each flange  217   a ,  217   b  is coupled to a respective arm  219   a ,  219   b , which are shown in their retracted position in which they sit within the axial profile of the body  201 . The arms  219   a ,  219   b  are flat plates, a first plate  219   a  of which has a substantially circular profile, a second plate  219   b  or which has a substantially semi-circular profile. On a circumferential edge of each plate  219   a ,  219   b  is a hole through which the respective shaft  205   a ,  205   b  is passed such that the respective flange  17   a ,  17   b  abuts the side of the arm  19   a ,  19   b  opposite the distal end of the shaft  5   a ,  5   b . The hole in each plate is a corresponding countersink (i.e. a conical hole arrangement) at one end of each hole. The combination of the arm  219   a  and the spring-clip  211   a  substantially prevents any axial movement of the shaft  205   a  within the passage  237   a . In contrast, the combination of the arm  219   b  and the spring-clip  211   b  substantially limits axial movement of the shaft  205   b  within the passage  237   b  to a distance equal to the thickness of the arms  219   a ,  219   b ; that is, around 1.2 mm. Thus, the second arm  219   b  can therefore be moved into and out of the plane of the first arm  219   a , once the first arm has been moved into its extended position. The arm  219   a  has a larger surface area than the arm  219   b.    
         [0135]      FIG. 19  shows an underside view of the fixing device of  FIG. 18 , which has wings  215   a ,  215   b , substantially the same as the wings  15   a ,  15   b , provided on the body  201 . 
         [0136]      FIG. 20  shows a top view of the fixing device of  FIGS. 18 and 19 , in which the arms  219   a ,  219   b  are located in the extended position. The recesses  207   a ,  207   b  are shaped to form a guide rail  241  in the top surface of the body  201 , to assist the automatic orientation of the body during automatic assembly of the fixing device. 
         [0137]      FIG. 21  shows the same view of the fixing device as  FIG. 19 , but with the arms  219   a ,  219   b  in the optimal extended position. A hollow  243  is provided in the rear surface of the body  201  for accommodating the second arm  219   b  when both arms  219   a ,  219   b  are in the retracted position. The first shaft  205   a  can be rotated in order to move the first arm  219   a  from its retracted position into its extended position, then the second shaft  205   b  can be moved axially to move the second arm  219   b  into the same plane as the first arm  219   a , and finally the second shaft  205   b  can be rotated to move the second arm  219   b  from its retracted position into its extended position. Similarly, the second shaft  205   b  can be rotated to move the second arm  219   b  from its extended position into its retracted position, the second shaft  205   b  can then be moved axially to move the second arm  219   b  out of the plane of the first arm  219   a , and finally the first shaft  205   a  can be rotated in order to move the first arm  219   b  from its extended position into its retracted position. 
         [0138]      FIG. 22  shows a body  301  of a fixing device. The body  301  is of a substantially cylindrical form, having an axial depth of approximately 11.5 mm and a diameter of approximately 20 mm. The body  301  has an anchor receiving aperture  303 , which passes axially through the body  301 , is internally threaded, and has a diameter of approximately 6.5 mm. The body includes a slot  304  similar to the slot  4 ; however, the slot  304  is substantially wider, and therefore can accommodate a more robust and/or stronger tool (not shown). The body  301  also includes two passages  337   a ,  337   b  that extend through the body  301 , each passage  337   a ,  337   b  having an axis parallel to, and spaced from, the axis of the anchor receiving aperture  303 . The two passages  337   a ,  337   b  are disposed diametrically opposite one another around the body  301 , set in from the edge of the body  301 , and are provided within respective recesses  307   a ,  307   b , substantially the same as recesses  7   a ,  7   b , in the top surface. Each passage  337   a ,  337   b  has an open-sided keyhole-shaped cross-section, and includes a constriction  345   a ,  345   b  for retaining a shaft within the circular portion of the keyhole shape. Either side of each passage  337   a ,  337   b  are provided two slots  347   a ,  347   c  and  347   b ,  347   d , respectively, each projecting semi-radially inward from the outer surface of the body  301  and running parallel to the axis of the passages  337   a ,  337   b . The slots  347   a ,  347   c ,  347   b ,  347   d  enable resilient biasing of the side walls of the shafts  337   a ,  337   b  to allow insertion of a shaft  305   a ,  305   b  radially into the circular portion of the keyhole shape, via the constriction  345   a ,  345   b . A shaft  305   a  can be inserted radially into the flared portion of the keyhole shaped passage  337   a . If a pressure is applied to the shaft  305   a  radially, then the shaft  305   a  can force the side walls of the passage  337   a  apart, widening the constriction  345   a . The shaft  305   a  can then move into the circular portion of the keyhole shaped passage  337   a , and the constriction  345   a  returns to its original size. The body  301  is also provided with two wings  315   a ,  315   b , substantially the same as the wings  15   a ,  15   b , diametrically opposed around the circumference of the body  301 , and offset from the passages  337   a ,  337   b.    
         [0139]      FIG. 23  shows a cross-section along line E-E of a fixing device having the body shown in  FIG. 17 , when inserted into a wall. The arms  319   a ,  319   b , substantially the same as the arms  19   a ,  19   b , are shown in their retracted position. The arms  19   a ,  19   b  are coupled to respective flanges  317   a ,  317   b . The wings  315   a ,  315   b  are shown having cut into plasterboard  323 , which is bonded to masonry wall  325  with adhesive  327 , to form a cavity  328 . The cavity  328  may vary in thickness between 10 mm and 25 mm, depending on the thickness of the adhesive  327  at the time the plasterboard  323  was placed in position against the wall  325 . An anchor  329 , in the form of a countersunk bolt with a screw thread engages with the complementary screw thread in the anchor receiving aperture  303  is located in the anchor receiving aperture  303 . The anchor  329  anchors a plate  335  to the plasterboard  323  by means of a corresponding countersunk arrangement (i.e. conical hole arrangement) at one end of a through-hole in the plate  335 . The plate  335  shown is a flat sheet with a depth of 3-4 mm, and having a width substantially greater than the diameter of the body  301 . If the body  301  has been over-inserted into the plasterboard  323 , such that the front surface lies within the hole in the plasterboard, below the front of the plasterboard  323 , then anchoring the plate  335  to the body  301  by means of anchor  329  will draw the body  301  into a position flush with the surface of the plasterboard  323 . For instance, tightening the anchor  329  draws the body  301  toward the plate  335 , by means of the complementary screw threads and thereby draws the arms  19   a ,  19   b  against the rear surface of the plasterboard  323 . 
         [0140]      FIG. 24  shows a rear view of the fixing device shown in  FIG. 23 , with the arms  319   a ,  319   b  shown in the retracted position. The body  301  is provided with stops  321   a ,  321   b , substantially the same as the stops  21   a ,  21   b . To accommodate a larger activation member on the tool, cut-out regions  324  are formed in the wings  319   a ,  319   b , of a size so as not to overlap the slot  304 . The cut-out regions  324  may be formed by cutting out portions from pre-formed wings  319   a ,  319   b ; however, in preferred embodiments, the cut-out regions  324  are integrally formed with the wings  319   a ,  319   b . For instance, the wings  319   a ,  319   b  may be cast, pressed or cut to include the cut-out regions  324 . 
         [0141]      FIG. 25  shows the same view of the fixing device as  FIG. 24 , but with the arms  319   a ,  319   b  in the optimal extended position, abutting stops  321   a ,  321   b  respectively. 
         [0142]      FIG. 26  shows a cross-section along line F-F of a fixing device having the body shown in  FIG. 22 , when inserted into a wall. The arms  319   a ,  319   b  have been coupled to their respective shafts  305   a ,  305   b  using respective flanges  349   a ,  349   b . The flanges  349   a ,  349   b  are each formed in a mushroom shape comprising a narrow portion, for insertion through a hole in one of the arms  319   a ,  319   b , and a head portion for retaining the arm  319   a ,  319   b  on the shaft, the head portion having a larger diameter than that of the hole. The narrow portion of the flange  349   a ,  349   b  is passed through the hole in the arms  319   a ,  319   b , before coupling securely to the main part of the shaft  305   a ,  305   b . Welding the flange  349   a ,  349   b  to the arm  319   a ,  319   b  secures the two components together. 
         [0143]      FIG. 27  shows a perspective view of an actuation member in accordance with the fixing device shown in  FIG. 26  that comprises a shaft  305   a , having an enlarged head  351   a  and a slot screw drive  313   a , and an arm  319   a  coupled thereto. The enlarged head  351   a  is substantially cylindrical in shape, and is positioned axially at one end of the shaft. The diameter of the enlarged head is larger than the diameter of the shaft and the diameter of the circular cross-section portion of the passage  337   a . The enlarged head therefore substantially limits axial movement of the shaft through the passage. 
         [0144]      FIG. 28  shows a body  401  of a fixing device. The body  401  is of a substantially cylindrical form, having an axial depth of approximately 11.5 mm and a diameter of approximately 16 mm. The body  401  has an anchor receiving aperture  403 , which passes axially through the body  401 , is provided splines  453  that project radially into the centre of the anchor receiving aperture  403 , and has a diameter of approximately 4.5 mm. A slot  404  is formed in a similar manner to the slot  4 . The body  401  also includes two passages  437   a ,  437   b  that extend through the body  401 , each passage  437   a ,  437   b  having an axis parallel to, and spaced from, the axis of the anchor receiving aperture  403 . The two passages  437   a ,  437   b  are disposed diametrically opposite one another around the body  401 , set in from the edge of the body  401 , and are provided within respective recesses  407   a ,  407   b , substantially the same as recesses  7   a ,  7   b , in the top surface. Each passage  437   a ,  437   b  has an open-sided keyhole-shaped cross-section, and includes a constriction  445   a ,  445   b  for retaining a shaft within the circular portion of the keyhole shape. On one side of each passage  437   a ,  437   b  is provided a slot  447   a ,  447   b , respectively, each projecting radially inward from the outer surface of the body  401  and running parallel to the axis of the passages  437   a ,  437   b . The slots  447   a ,  447   b , enable resilient biasing of one of the side walls of the shafts  437   a ,  437   b  to allow insertion of a shaft  305   a ,  305   b  radially into the circular portion of the keyhole shape, via the constriction  445   a ,  445   b . A shaft  305   a  can be inserted radially into the flared portion of the keyhole shaped passage  437   a . If a pressure is applied to the shaft  305   a  radially, then the shaft  305   a  can force the side walls of the passage  437   a  apart, widening the constriction  445   a . The shaft  305   a  can then move into the circular portion of the keyhole shaped passage  437   a , and the constriction  445   a  returns to its original size. The body  401  is also provided with two wings  415   a ,  415   b , substantially the same as the wings  15   a ,  15   b , diametrically opposed around the circumference of the body  401 , and offset from the passages  437   a ,  437   b.    
         [0145]      FIG. 29  shows a perspective view of the activation tool  29 , with the activation member  31 , the shaft  34  and the handle  35 . 
         [0146]      FIG. 30  shows a fixing device, comprising a body  501 , being substantially cylindrical in shape and defining a hollow cavity therein. The body  501  has a diameter for insertion into a hole of approximately 13 mm and a depth of approximately 17 mm. The body  501  includes a casing  557 , configured to sit within a hole in a plasterboard sheet, and an integral plate  555  that forms the top surface of the body  501 , and has a diameter larger than the diameter for insertion into a hole, of approximately 14 mm. The body  501  is provided centrally with a threaded anchor receiving aperture  503  in the integral plate  555  that extends from the top surface of the body  501  into the hollow cavity. The body is further provided with first and second shafts  505   a ,  505   b , provided within respective first and second passages that are parallel to and axially spaced from the axis of the anchor receiving aperture  503 , and extend from the top surface of the body  501 , through the hollow cavity to the lower surface of the body  501 . The passages are unthreaded, and circular in cross-section. Nuts  559   a ,  559   b  are provided on top ends of the respective shafts  505   a ,  505   b . Each shaft  505   a ,  505   b  is provided with a respective slot screw drive  513   a ,  513   b , also on their top ends, substantially the same as the screw drives  13   a ,  13   b.    
         [0147]      FIG. 31  shows the fixing device of  FIG. 30  inserted into plasterboard  523 . Each shaft  505   a ,  505   b  is threaded  561   a ,  561   b  at its top end in order to threadably receive a respective nut  559   a ,  559   b  thereon. Each shaft  505   a ,  505   b  has at a flange  517   a ,  517   b  disposed on its lower end for the coupling of a respective arm  519   a ,  519   b  thereto. The flanges  517   a ,  517   b , arms  519   a ,  519   b  and their means of coupling are substantially the same as described in respect of flanges  17   a ,  17   b  and arms  19   a ,  19   b . Movement of the arms  519   a ,  519   b  between their respective extended and retracted positions is substantially the same as that described with respect to arms  19   a ,  19   b . The shafts  505   a ,  505   b  may be individually rotated in order to move the arms  519   a ,  519   b  from a retracted position into the extended position shown in  FIG. 25 . Tightening the nuts  559   a ,  559   b  on the shafts  505   a ,  505   b  draws the arms  519   a ,  519   b  against the rear surface of the plasterboard  523  adjacent the cavity  528 . Pressure between the arms  519   a ,  519   b  and the integral plate  555  holds the fixing device securely in the plasterboard  523 . A forged steel eye bolt  529  is threadably received in the anchor receiving aperture  503 . The forged steel eye bolt  529  secures a cap  563  over the integral plate  555  such that access to the nuts  559   a ,  559   b  is prevented without removal of the cap  563 . The cap  563  is substantially cup-shaped, and includes a hole in its flat end for receiving the forged steel eye bolt  529  therethrough. 
         [0148]      FIG. 32  shows a rear view of the fixing device of  FIGS. 30 and 31  with the arms  519   a ,  519   b  shown in the retracted position. 
         [0149]      FIG. 33  shows the same view as  FIG. 32 , but with the arms  519   a ,  519   b  shown in the extended position. 
         [0150]      FIG. 34  shows an arm  619 , having a hole  665  therethrough at one end, and a tongue  667  adjacent the hole  665 . The tongue is formed by partially cutting out a portion of the flat arm  619 , which is then bent out of the plane of the flat arm  619 . 
         [0151]      FIG. 35  shows the arm  619  having a shaft ( 605 , not shown) located within the hole  665 . At one end of the shaft  605  is a flange  617 . The shaft  605 , excluding the flange  617 , may be configured in the same way as any shaft previously described herein. The flange  617  has a socket  669  for receiving the tongue  667  therein, when the shaft  605  has been fully inserted into the hole  665 . The socket  669  is sized to receive the tongue  667  in a close fit, so that there is substantially no rotational movement between the shaft  605  and the arm  619 , about the axis of the shaft  605 . 
         [0152]      FIG. 36  shows a partial cross section of the arrangement of  FIG. 14  along the line G-G. The flange  617  abuts the rear face of the arm  619  to prevent axial movement of the shaft  605  in one direction through the hole  665 . The shaft may comprise limiting means such as an enlarged head or a circlip, as hereinbefore described. Once the shaft  605  is inserted into a passage of a fixing device body, the arm  619  is held between the rear surface of the body and the flange  617 , so as to prevent any movement of the arm  619  along the axis of the shaft  605 . Further, the engagement of the tongue  667  with the socket  669  prevents any movement of the arm  619  rotationally about the axis of the shaft  605 , relative to the shaft  605 . Accordingly, rotation of the shaft  605  about its axis causes corresponding rotation of the arm  619  about the shaft&#39;s  605  axis.

Technology Category: 2