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FIELD OF THE INVENTION  
       [0001]     This invention relates to couplers and more particularly to couplers for interconnecting scaffolding.  
       BACKGROUND OF THE INVENTION  
       [0002]     Scaffolding is commonly constructed from lengths of steel or aluminum tubes interconnected to each other to form an open structural framework. The size and configuration of the structure depends on the application. The interconnection of the tubes is normally made by two right angle couplers (“double couplers”) which are joined together. One of these double couplers can interconnect two of the three tubes that will normally meet at a right angle crossing of a scaffold structure. A second double coupler is required to interconnect a third tube to the first two.  
         [0003]     The couplers are normally locked to the tubes by one or more nut and bolt locking devices. However, such couplers suffer from disadvantages. Their fastening and unfastening is time consuming and is inconvenient in requiring use of a wrench. Additionally, two hands are normally required to hold the coupler during the initial stages of fastening and the nuts and bolts are often corroded, making it difficult to thread and tighten the nuts. Also, the locking device may be under or over tightened on the tubes, leading to slipping or thread stripping respectively, which may compromise the safety of the scaffold structure.  
       SUMMARY OF THE INVENTION  
       [0004]     The invention may be summarised according to a first broad aspect as a coupling apparatus for interconnecting three scaffold members comprising: a support coupler and two connector couplers for attachment to three scaffold members; the support coupler having a base interconnected to the connector couplers, a lever hinged to the base, and a locking device, the base and the lever defining a pocket for laterally receiving a length of a scaffold member; the connector couplers each defining a pocket for receiving a length of a scaffold member and having a locking device; each of the locking devices being movable from a release condition, to allow a scaffold member to be positioned in or removed from the pocket, to a locked position, to secure the scaffold member in the coupler; wherein the pockets are oriented to secure three scaffold members at relative angles to each other.  
         [0005]     The invention may be summarised according to a second broad aspect as a two coupler apparatus for interconnecting two scaffolding members wherein at least one coupler is defined by: a base interconnected to a second coupler; a lever hinged to the base, the base and the lever defining a pocket for laterally receiving a length of a scaffold member; an arm hinged to the base; the lever having an slot sized to receive the arm; the arm defining a hole positioned to extend beyond the lever when the arm is within the slot; a wedge adapted for insertion through the hole to slidably move against the lever when the arm extends within the slot to wedge the arm within the lever whereby the scaffold member is locked within the at least one coupler.  
         [0006]     The invention may be summarised according to another broad aspect as a two coupler apparatus for interconnecting two scaffolding members wherein at least one coupler is defined by: a base interconnected to a second coupler; a lever hinged to the base, the base and the lever defining a pocket for laterally receiving a length of a scaffold member; an arm hinged to the base, the arm having a protrusion at a free end; the lever having an slot adapted to receive the arm; a circular wedge pivotally mounted on the arm, the circular wedge circumferentially increasing in thickness to define a cam surface for engagement with the protrusion; the circular wedge being rotatable on the arm between the lever and the protrusion in a direction of increasing thickness to create a wedging action between the protrusion and the cam surface acting to press the lever onto the scaffold member to lock the scaffold member within the pocket.  
         [0007]     The invention may be summarised according to a further broad aspect as a two coupler apparatus for interconnecting two scaffolding members wherein at least one coupler is defined by: a base interconnected to a second coupler; a lever hinged to the base, the base and the lever defining a pocket for laterally receiving a length of a scaffold member; an over-centre hand-lever mechanism for intercoupling the base and the lever, the over-centre hand-lever mechanism having an adjustable length and being selectively actuatable when intercoupling the base and the lever to lock the lever and the base to a scaffold member.  
         [0008]     Advantageously, the triple coupler allows three scaffold members to be interconnected with only one coupling apparatus thereby replacing the two double couplers normally used. Assembly is then achieved by the handling of one apparatus instead of two.  
         [0009]     Additionally, the angle between the three scaffold members can be fixed by the triple coupler. This eliminates the need to adjust the angle of a second double coupler relative to a first double coupler as is necessary where two double couplers are used.  
         [0010]     Specific embodiments of the couplers, namely the wedge coupler, the circular wedge coupler and the hand-lever coupler, have the advantage that they do not rely on threaded bolts and nuts to fasten the couplers around the scaffold members. This eliminates the problems of stripped or rusted threads associated with bolt-and-nut locking devices.  
         [0011]     Additionally, the hand-lever coupler may be fastened or unfastened quickly without the use of any hand tools.  
         [0012]     Also, the wedge coupler and the circular wedge coupler are simple to fabricate, may be fastened or unfastened rapidly and the circular wedge coupler has no separable parts.  
         [0013]     Other aspects and features of the invention will become apparent to those of ordinary skill in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     Preferred embodiments of the invention will now be described with reference to the attached drawings in which:  
         [0015]      FIG. 1  is a perspective view of a bolt-and-nut triple coupler in which segments of scaffolding tubes are shown.  
         [0016]      FIG. 2  is a perspective view of the bolt-and-nut triple coupler of  FIG. 1 .  
         [0017]      FIG. 3  is a perspective view of a wedge triple coupler.  
         [0018]      FIG. 4  is an enlarged perspective view of a wedge and an arm used in the triple coupler of  FIG. 3 .  
         [0019]      FIG. 5  is a perspective view of a circular wedge triple coupler.  
         [0020]      FIG. 6A  and  FIG. 6B  are perspective views of a circular wedge and arm, shown separately and assembled, respectively, of the triple coupler of  FIG. 5 .  
         [0021]      FIG. 7  is a perspective view of a hand-lever triple coupler.  
         [0022]      FIG. 8A, 8B ,  8 C and  8 D are perspective views of a base, an inner lever, a hand lever and a T-shaped catch assembly of the coupler of  FIG. 7 .  
         [0023]      FIG. 9  is a side view of a coupler of the hand-lever triple coupler of  FIG. 7 , with a scaffold member, in an open position.  
         [0024]      FIG. 10  is the coupler of  FIG. 9 , shown to a larger scale, in an almost closed position. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0025]      FIG. 1  depicts a triple coupler  10  interconnecting a vertical scaffold member  8 A and two horizontal scaffold members  8 B,  8 C. The triple coupler  10  includes a heavy duty vertical support coupler  12  and two horizontal connector couplers  14 A,  14 B.  
         [0026]      FIG. 2  depicts a base  16  of the vertical support coupler  12 . The base  16  has two plates  17 ,  19  joined at a right angle. Two flanges  15  extend at right angles from the edges of the plates  17 ,  19 . The flanges  15  have inner edges that define an arcuate pocket  22 . The flanges  15  have pair of registering holes that define a pivot axis  21  adjacent an outer end of the plate  19  and a pivot axis  28  adjacent an outer end of the plate  17 .  
         [0027]     The base  16  further includes a lever  18  defined by a plate  25  that has two flanges  27 , and a horizontal slot  30  opening from the free end. The two flanges  27  extend from the free end of the plate  25  along its side edges and have inner edges that are arcuate. The lever  18  is pivotally connected, on the axis  21 , to the flanges  15  on the base  16 .  
         [0028]     The coupler  12  includes a locking device  24  comprising a bolt  26 , which is pivotally connected to the base  16  on the axis  28  at the opposite side of the pocket  22 . A nut  34  is threaded on the bolt  26  which also carries a washer  32 . The horizontal slot  30  receives the bolt  26  when the bolt  26  is rotated about the pivot axis  28  and into position shown in  FIG. 1 .  
         [0029]     The vertical support coupler  12  is locked to the vertical scaffold member  8 A by the locking device  24 . The operation of the locking device  24  is as follows. The vertical scaffold member  8 A ( FIG. 1 ) is placed into the pocket  22 . The lever  18  is then swung to close the flanges  27  around scaffold member  8 A. The lever  18  thus closes the pocket  22 . The flanges  27  and the flanges  15  grip the vertical scaffold member  8 A ( FIG. 1 ) when the vertical support coupler  12  is closed. The bolt  26  is then swung into the slot  30  in the lever  18  and the nut  34  rotated against the washer  32  to press the lever  18  into gripping engagement with the scaffold member  8 A. Thus, when the nut  34  is tightened, the vertical scaffold member  8 A is securely locked in the pocket  22  of the coupler  12 .  
         [0030]     The structure of each horizontal connector coupler  14 A,  14 B depicted in  FIGS. 1 and 2  is basically the same as that of the vertical support coupler  12 . Only the structure which differs will be described with reference to the lower horizontal connector coupler  14 B. Unless otherwise specified, the structure of the upper horizontal connector coupler  14 A is the same as that of the lower horizontal connector coupler  14 B.  
         [0031]     The lower horizontal connector coupler  14 B has a stopper plate  48  near the pivot of a bolt  50 . The stopper plate  48  prevents the bolt  50  from rotating too far from its locked position when it is released. The stopper plate  48  maintains the bolt  50  at an angle in the range of 10° to 15° from the plane of a horizontal plate  43  of a base  42 .  
         [0032]     The horizontal connector couplers  14 A,  14 B are rigidly fixed to the vertical support coupler  12  by rivets  36 . As shown in  FIGS. 1 and 2 , the horizontal connector couplers  14 A,  14 B are offset and orthogonal to each other and to the vertical support coupler  12 . The vertical plate  45 B of the base  42  of the lower horizontal connector coupler  14 B is riveted to the plate  17  of the vertical support coupler  16  and the vertical plate  45 A of the upper horizontal connector coupler  14 A is riveted to the plate  19  of the coupler  12  as is clearly shown in  FIG. 2 . The vertical plate  45 B of the lower horizontal connector coupler  14 B extends below the plate  17  of the coupler  12  and the vertical plate  45 A of the upper horizontal connector coupler  14 A extends above the plate  19  of the coupler  12 . On a portion of the vertical plate  45 B, which extends below the coupler  12 , there is a reinforcing knot  40 . The reinforcing knot  40  is a roughly semi-hollow-ball shaped protrusion formed in the vertical plate  45 B. The reinforcing knot  40  prevents the bending of the vertical plate  45 B by pressing against the vertical scaffold member  8 A when a vertical force of the horizontal scaffold member  8 C against the base  42  would otherwise tend to bend the portion of the vertical plate  45 B extending below the base  16 . A vertical plate  45 A of the upper horizontal connector coupler  14 A does not have a similar reinforcing knot.  
         [0033]     Other locking devices may be utilized as exemplified in the following Figures.  FIG. 3  depicts a triple coupler  60  which utilizes a bolt-and-nut locking device  62  to secure a vertical support coupler  64  as in  FIGS. 1, 2 . However, two horizontal connector couplers  66  utilize a different locking device.  
         [0034]     The couplers  66  have a base  72  with flanges having arcuate inner edges which define a pocket  76 . A lever  74  is hinged at one end to the base  72 . The lever  74  also has flanges with arcuate inner edges. The lever  74  has an outwardly open slot  78  as in the levers of the bolt-and-nut couplers of  FIGS. 1, 2 . However, in the present embodiment, the bolt-and-nut have been replaced by an arm  70  and a wedge  68 .  
         [0035]      FIG. 4  depicts the wedge  68  separately from the arm  70 . The arm  70  has a circular hole  71  adjacent one end and an elongate hole  80  adjacent the other end. The arm  70  is hinged to the base  72  by a pin (not shown) passing opposite the lever  74  through the hole  71 . The wedge  68  has a wide end  84  with a stopper  87 , and tapers to a narrow end  82 , which has a hole  86  defined therein.  
         [0036]     In use, a scaffold member (not shown) is positioned into the pocket  76  and the lever  74  is rotated to close the pocket  76  around the scaffold member. The arm  70  is then rotated into the slot  78  such that a portion of hole  80  extends above the lever  74 . The small end  82  of the wedge  68  is slid through that portion of the hole  80 . As the wedge  68  (driven by hammer blows) is advanced through the hole  80 , the increasing taper of wedge  68  forces more of the arm above the lever  74 . The lever  74  is thus pressed against the scaffold member within the pocket  76 , thereby locking the scaffold member within the coupler  66 .  
         [0037]     The wedge  68  is also designed to be retained within the hole  80  even when it is not locked against the lever  74 . In particular, the stopper  87  at the wide end  84  of the wedge  68  is sufficiently wide that it cannot fit through the hole  80  in the arm  70 . A retaining means (not shown) such as a cotter pin, rivet, or other fastener, is inserted through the hole  86  in order to retain the wedge  68  within the hole  80 .  
         [0038]      FIG. 5  depicts a triple coupler  90  comprised of a bolt-and-nut coupler  92  and two circular wedge couplers  94 . The bolt-and-nut coupler  92  is essentially as described with respect to  FIGS. 1 and 2  but the two couplers  94  utilize another locking device. Each coupler  94  has a base  98 , with flanges having arcuate inner edges, which defines a pocket  100 . A lever  96  is hinged at one end to the base  98 . The lever  96  also has flanges with arcuate inner edges and can be swung to close the pocket  100  around a horizontal scaffold member (not shown). The lever  96  has an outwardly open slot  104 . This structure is the same as that of the bolt-and-couplers of  FIGS. 1, 2 . However, in the present embodiment, the bolt-and-nut have been replaced with an arm  102  and a circular wedge  105 .  
         [0039]      FIG. 6A  depicts the arm  102  and the circular wedge  105  separately. The arm  102  has a hole  101  adjacent one end for pivotal attachment to base  98  and at its opposite end a protrusion  112  projecting perpendicular to an axis of the hole  101 . The arm  102  is hinged to the base  98 , opposite the lever  96 , through the hole  101 . The circular wedge  105  has a hexagonal outer surface and a circular inner surface. The circular wedge  105  has a depression  108 , which defines the minimum thickness of the circular wedge  105 . A tapered upper surface  110  which begins at a leading edge  117  of the depression  108  and extends around the circumference of the circular wedge  105  to a stopper  114  that divides the tapered upper surface  110  from a second edge  113  of the depression  108 . When the circular wedge  105  is assembled onto the arm  102  ( FIG. 6B ) it can rotate freely about the shaft  111  of the arm  102  except when moved into engagement with the protrusion  112 . The depression  108  is sufficiently wide to receive the protrusion  112 . When the arm  102  is assembled to the coupler  96 , a spring washer  106  ( FIG. 5 ) is preferably positioned on the arm beneath the circular wedge  105 .  
         [0040]     The operation of the coupler  94  is as follows. A scaffold member (not shown) is placed within the pocket  100 . The lever  96  is swung over the scaffold member and the arm  102  is rotated into the slot  104  in the lever  96 . The circular wedge  105  rests against spring washer  106 , which rests on the lever  96 . The depression  108  rests against the protrusion  112 . To tighten the locking device, the circular wedge  105  is pressed against the lever  96  and rotated to position the protrusion  112  against a leading edge  117  of the tapered upper surface  110 . As the circular wedge  105  is further rotated (e.g. by use of a wrench), the wedge action of the surface  110  against the protrusion  112  presses the lever  96  against the scaffold member within the pocket  100 , thereby locking the scaffold member to the coupler  96 . The stopper  114  limits the rotation of the circular wedge  105  against the protrusion  112  thereby preventing the circular wedge  105  from being over-rotated. The spring washer  106  secures the circular wedge  105  against slipping once it is tightened.  
         [0041]     A triple coupler  120  of FIGS.  7  to  10  include a bolt-and-nut vertical support coupler  122 , as in  FIGS. 1, 2  and two horizontal couplers  124 . As best depicted in  FIG. 8A , each coupler  124  has a base  126  with a rear vertical plate  214  and a bottom plate  213  joined at a right angle to a bottom edge of the rear vertical plate  214 . A latch plate  209  is joined to the top edge of the rear vertical plate  214  and extends outwardly and slightly downwardly. A square hole  210  extends through the latch plate  209 . Two flanges  211  extend along opposite edges of the plates  213 ,  214 . The inner edges of the flanges  211  define a arcuate pocket  144  ( FIG. 7 ). The flanges  211  have aligned holes  212  adjacent the outward end of the plate  213 .  
         [0042]     An inner lever  128  is hinged to the holes  212  of the base  126 . The inner lever  128 , as shown in  FIG. 8B , has a curved plate  215  with a slot  218  defined at its lower edge. The curved plate  215  has two upper ears  216  at its upper corners and two lower ears  241  at its lower corners. Aligned holes  217  extend through each of the ears  241  and aligned holes  240  extend through each of the ears  216 . A hinge pin  136  ( FIG. 9, 10 ), extending through holes  212  and  217 , pivotally connects inner lever  128  to the base  126 .  
         [0043]     A hand lever  130  shown in  FIG. 8C  is also pivotally connected to the inner lever  128 . The hand lever  130  has a main plate  219  with a curved handle  221  extending downward from its lower edge. A narrow elongate vertical hole  225  is cut through the centre of the main plate  219 . A wide upwardly open slot  224  extends downward from the upper edge of the main plate  219 . Two side plates  220  are joined at right angles to upper side edges of the main plate  219 . Two aligned holes  223  are defined in the outermost ends of the side plates  220  and two aligned holes  222  are defined in the side plates  220  at a intermediate location. The specified hinge pin,  150  ( FIGS. 9, 10 ) extend through pairs of holes  223  and  240  to pivotally connect hand lever  130  to the inner lever  128  as best seen in  FIG. 9 .  
         [0044]     A T-shaped catch assembly  164  of  FIG. 8D  is comprised of a pin member  226  and a hook member  227 . The pin member  226  has a circular protrusion  229  extending from each end. The protrusions  229  are slightly smaller in diameter than the holes  222  in the hand lever  130 . The pin member  226  also has a square hole  228  extending through it. The hook member  227  has a plate  231  with a hook  230  at one end. Extending from an opposite end of the plate  231  is a tapered neck  232 , which joins to a rectangular section  233  that is slightly smaller in size than the hole  228  in the pin member  226 . The rectangular section  233  is joined to a bolt section  234  threaded for engagement by a nut  236 .  
         [0045]     To assemble the hook member  227  to the pin member  226 , the bolt section  234  and the rectangular section  233  of the hook member are inserted through the hole  228  in the pin member  226 . The nut  236  is then threaded onto the bolt section  234  to retain the pin member on the hook member. The T-shaped catch assembly  164  is then connected to the hand lever  130  by outwardly flexing the side plates  220  and inserting projections  229  of the pin member  226  into the holes  222  of the hand lever  130 .  
         [0046]     A security device  134 ,  FIGS. 9, 10 , has a catch  137  slidably positioned at an outer face of the hand lever  130 . An L-shaped hook member  138  having a hook  139  and a plate  141  joined at a right angle is slidably positioned at the inner face of the hand lever  130 . The catch  137  and the plate  141  of the L-shaped hook member  138  are interconnected and held in position by a screw  143  extending through the hole  225  in the hand lever  130 . A spring  140  is located in the hole  225  between an extension  142  of the L-shaped hook member  138  protruding through the hole  225  and one end of the hole  225 . The spring  140  is retained in the hole  225  by the plate  141  and the catch  137 , which block opposite sides of the hole  225 . The catch  137  and the L-shaped hook member  138  are biased away from the handle  221  by the spring  140 .  
         [0047]     The operation of the coupler  124  is described with regard to  FIGS. 9 and 10 . A scaffold member  160  is placed in the pocket  144 . The hand lever  130  is used to rotate the inner lever  128  to close the pocket  144 . At the same time, the T-shaped assembly  164  is rotated until the hook  230  is inserted into the hole  210  of the base  126  and hooked around the plate  209 . The hand-lever  130  is then counter rotated until the hook  139  catches around the hinge pin  136 . The spring  140  biases the hook  139  around a central part of the hinge pin  136  to secure the coupler  124 .  
         [0048]     The over-centre design on the hand lever  130  also helps to hold the coupler  124  closed. The hook member  227  pivots around the protrusions  229 . When closed, the axis of protrusions  229  lies below a plane defined by the hinge pin  136  and the edge of the hole  210 . In this configuration, the outward force of the scaffold member  160  operating along that plane tends to further rotate the hook member  227  around the axis of the protrusions  229  to force the protrusions  229  downward rather than opening the coupler.  
         [0049]     The functional length of the hook member  227  may be adjusted by rotation of the nut  236  to vary the force required to release the hand lever. A set of double convex washers (not shown) are placed over the bolt end  234  before threading the nut  236  onto the bolt end  234  in order to provide the resistance necessary to accommodate the over centre locking action of the hook  230 .  
         [0050]     To release coupler  124 , the catch  137  is depressed towards the handle  221  to press the extension  142  against the spring  140 . The compression of the spring  140  allows the L-shaped hook member  138  to clear the hinge pin  136  when the hand lever  130  is rotated so that the protrusions  229  are above the plane of the hinge pins  136  and the edge of the hole  210 .  
         [0051]     The gripping action of the hand lever coupler  124  coupler may not be as secure as other couplers described herein but has the advantage of rapid action.  
         [0052]     It will be understood that the grip of the couplers herein described can be improved by designing some indentations on portions of the couplers which contact the scaffolding members. For example, the grip of the coupler described with reference to FIGS.  7  to  10  can be improved by designing some indentations on the curve plate  215  which contacts the scaffold tube.  
         [0053]     Both the coupler and the scaffold members described herein are typically comprised of steel or aluminum but may be made of any suitable material. Additionally, the scaffold members are shown to be tubular but may be of other cross-sectional shapes including rectangular members.  
         [0054]     Alternative arrangements of the triple coupler are contemplated including interconnecting the couplers at other angles or pivotally interconnecting them. Additionally, other means of interconnecting the couplers may be used such as welding or casting as a unitary assembly.  
         [0055]     Although the couplers may be used in different orientations, it is preferable to utilize a bolt-and-nut coupler for the vertical scaffold member because it achieves a firmer grip and is less prone to unintended loosing.  
         [0056]     It will also be understood that the couplers described with respect to FIGS.  3  to  9  may be used for coupling devices other than triple couplers. In particular, they may be used for an orthogonal, a parallel or a rotatable two coupler apparatus.  
         [0057]     The above description of embodiments should not be interpreted in any limiting manner since variations and refinements can be made without departing from the spirit of the invention. The scope of the invention is defined by the appended claims and their equivalents.

Summary:
A two coupler apparatus for interconnecting two scaffolding members wherein at least one coupler is defined by: a base interconnected to a second coupler and a lever hinged to the base. The base and the lever define a pocket for laterally receiving a length of a scaffold member. An arm is hinged to the base and the lever has a slot sized to receive the arm. The arm defines a hole positioned to extend beyond the lever when the arm is within the slot. A wedge is adapted for insertion through the hole to slidably move against the lever when the arm extends within the slot to wedge the arm within the lever whereby the scaffold member is locked within the at least one coupler.