Abstract:
A method for securing a counterweight guiding system in performance rigging in places of entertainment. An elongate guide rail has a cross-section which interlocks with a clip, the clip extending transversely beyond the guide. The guide rail is secured to a support by fastening the clip to the support, the guide itself not requiring any specific fastening points.

Description:
This application claims the benefit of Ser. No. 60/223,218, filed Aug. 4, 2000. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to guiding systems, and particularly to securing a guiding system for counterweights in performance rigging in places of entertainment. 
     BACKGROUND 
     Performance rigging includes numerous items of equipment including curtains, lights, scenic elements and other performance enhancements that must be moved up and down or in and out of the performance space balanced by counterweights. Typically, counterweights are installed in frames that are, in turn, guided by long runners either singly or in pairs. 
     A generally vertical runner is usually connected to a generally horizontal support member by attachment means such as bolts passing through attachment holes in the runners and the support. In order that the runner can be vertically adjustable relative to the support, a plurality of attachment holes must be provided along at least a portion of the height of the runner. 
     Furthermore, a plurality of support members may be necessary, in which case there must be a correspondence between the separation of the support members and the spacing of the particular attachment holes. 
     Such an arrangement is inconvenient, since it requires relatively precise positioning of the runner. This can be overcome by providing longitudinally elongate attachment holes in the runner. However, adjustment of the rigging can be needlessly time-consuming, especially if any of the structural members is misaligned. 
     Since performance rigging may need to be reconfigured between performances, the guide system the capability of being easily assembled and dismantled. There is therefore a need for a guide system for which alignment is less critical. 
     SUMMARY OF THE INVENTION 
     The present invention is a system in which an arbor is guided between generally vertical pairs of rails or guides attached to generally horizontal supports. While the horizontal support has a plurality of attachment holes spaced to define a consistent spacing between the members of a given pair of guides, the guides themselves do not have distinct attachment points; instead, each guide engages a clamp or clip which is in turn attached to the support. Therefore, the guide is not confined to discrete vertical relationships with the support. The clip and the guide are configured to have precisely mating surfaces which preclude undesired movement of the guide relative to the support. Also, the clip can be attached to a backing plate instead of to the support. This allows the attachment of an additional length of guide or of various auxiliary devices to the guide, without the necessity of any attachment holes in the guide. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a counterweight arbor guide system. 
     FIG. 2 is a side elevation of a portion of a guide of the assembly secured with a clip to a support 
     FIG. 3 a plan view of the elements of FIG. 2 
     FIG. 4 is a side elevation of portions of two colinear guides spliced together using the clip and a backing plate. 
     FIG. 5 is a plan view of the elements of FIG.  4 . 
     FIG. 6 is a side elevation of a portion of the guide. 
     FIG. 7 is a plan view of the guide. 
     FIG. 8 is a side elevation of a portion of the clip. 
     FIG. 9 is a plan view of the clip. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, FIG. 1 shows a guide assembly or system  100  including a generally vertical elongate guide  110  with a generally “J” shaped cross section. As best seen in FIGS. 6 and 7, the J-shaped cross section includes a guide flange  112 , a strut  114  extending from the guide flange  112  and a foot  116  extending from the strut  114 , the foot  116  having a stop  118  spaced from the strut  114  and a ramp  120  intersecting the stop  118 . Normally, two such guides  110  are attached to a support with a predetermined spacing between them. The support is typically a generally horizontal support member  102 . Although the J-shaped cross section for the guide  110  is preferred, other cross-sections may be selected. 
     The means of attachment of the guide  110  to the support member  102  includes a clip  130  having a connector portion  132  and an interlock portion  134  (FIGS.  8  and  9 ). The interlock portion  134  includes a ramp-contacting surface  136  and a shoulder  138 . Thus, as seen in FIG. 3, the interlock portion  134  of the clip  130  and the foot  116  of the guide  110  are configured to have complementary surfaces. The support member  102  is typically permanently attached to some suitably strong feature of a building. 
     The connector portion  132  of the clip  130  has an attachment hole  150  for accepting a fastener such as a screw  152 . The screw  152  typically has a hexagonal head for engaging a wrench, although other types of screw can be used. The support member  102  has a plurality of corresponding holes  104  that can receive the screw  152 . The spacing of each receiving hole  104  from another (which may or may not be its nearest neighbor) is selected to correspond with the defined spacing between cooperating guides  110 . Each receiving hole  104  is typically sized to provide clearance for the screw  152  which can then be secured with a nut  154 . Alternatively, the receiving hole  104  may be tapped to threadedly accept the screw  152 . 
     In the guide system  100  as installed, the guide  110  is in a desired position relative to the support member  102  and the clip  130  is attached to the support member  102  with the screw  152 . When the screw  152  is tightened, the complementary surfaces of the clip  130  and the guide  110  engage as in FIG.  3 . The ramp-contacting surface  136  abuts the ramp  120 , and the shoulder  138  contacts the stop  118 . Thus the guide  110  is precisely located vertically relative to the support member  102 , while being precluded by the configurations of the complementary surfaces from undesired sideways movement. 
     The spacing of the cooperating guides  110  is such as to accept an arbor or shoe  160 , which can be moved up and down therebetween. Typically, the arbor  160  is configured to slidingly engage the guide flange  112  of each cooperating guide  110 . Extending from the arbor  160  as in FIG. 1 is a U-shaped rail  162  having a cross-piece  164  for attaching a cable (not shown). Bars  166  extend downwardly from the rail  162  for supporting selected counterweights  168 . 
     In another embodiment of the invention, shown in FIGS. 1,  4  and  5 , a second guide  111  is spliced to the first guide  110  in order to extend the vertical height of the assembly  100 . In this embodiment, the clip  130  has a plurality of attachment holes  150  in the connector portion  132 . Instead of being attached to the support member  102 , it is secured to a backing plate  170 . The clip  130  and the backing plate  170  are tightened against both the first and second guides  110  and  111 . The backing plate  170  need merely be a flat piece of material with appropriately located holes. This provides a secure connection between the first and second guides  110  and  111 , thus obviating any need to provide fastening holes in the guides. 
     In yet another embodiment of the invention, the guide  110  may be employed as a mount for an accessory such as a limit switch, sensor or end stop. In this case, the clip  130  and backing plate  170  would be secured against the guide  110 , the backing plate  170  being either attached to or an integral part of the structure of the accessory  172 . 
     Note that one extremity of the clip  130  has a lip  140  protruding slightly beyond a support-facing surface  142  of the connector portion  132 , the support-facing surface being defined as that surface intended to face the support member  102  or backing plate  170 . The lip  140  is effectively a fulcrum to provide leverage in securing together the clip  130 , the guide  110  and the support member  102  or backing plate  170 . If the lip  140  were absent, the security of the attachment of the various components would be critically dependent on their relative dimensions, and could be compromised by small dimensional variations. The clip  130  is sized relative to the guide  110  so that when it retains the guide  110  against the support member  102 , the support-facing surface  142  is precluded from significant contact with the support member  102 ; the retaining force between the clip  130  and the support member  102  is concentrated at the lip  140 . Similar considerations apply to the relationship between the clip  130  and the backing plate  170 . 
     Note also that there would typically be a plurality of support members  102  at different heights. 
     In the first embodiment, the system  100  is assembled as follows. The guide  10  is suitably positioned relative to the support member  102 , and secured thereto by aligning the clip  130  with the receiving hole  104 , and fastening together the clip  130 , the guide  110  and the support member  102  with the screw  152  and a nut. To allow for later adjustment, the screw  152  need not be completely tightened at this stage. The cooperating guide  110  is similarly fastened to the support member  102  at another appropriate receiving hole  104 . The operation is repeated at any other support member  102  as needed, each screw  152  ultimately being completely tightened before installation of the arbor  160 . The arbor  160  is then hoisted with the cable to a position of alignment with the guides  110 , wherefrom it is lowered so that it slidingly engages the guide flanges  112  of the cooperating guides  110 . The required performance rigging and the appropriate mass of counterweights are then installed, as known in the art. 
     The system  100  is versatile and lends itself to simple assembly and dismantling. In particular, since there is no need for fastening holes in the guide  110 , it can be clamped anywhere along its height and its vertical position is continuously variable. An assembler is therefore freed from having to be concerned with vertically aligning the guide  110 . 
     The system  100  has been shown and described in connection with various embodiments. Whereas preferred forms of the invention have been shown and described, it will realized that modifications may be made thereto without departing from the scope of the following claims.