Abstract:
A secondary pivot adapted to interrupt the periodic motion of a trapeze so as to cause the trapeze performer to experience rotational acceleration is disclosed. The term “secondary pivot” is defined to mean a selectively engageable pivot interposed at preselected intermediate positions along the respective lengths of the suspension lines of the trapeze between their points of suspension and the trapeze bar. A compound trapeze which includes a secondary pivot is also disclosed. Methods which include a step of restraining the periodic motion of a trapeze so as to cause the trapeze performer to experience rotational acceleration are also disclosed.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to trapezes and methods of using same.  
         [0003]     2. Description of the Related Art  
         [0004]     A trapeze is a device that has long been associated with circuses and aerial performers. Although the rigging equipment and materials of construction have been upgraded over time, the basic design has remained the same for well over a hundred years. In general, a trapeze consists of a short bar suspended near or at its ends by suspension lines, e.g., cables, so that it is free to swing back and forth in a regular fashion. The length of bar between the suspension lines is selected to be sufficiently long to accommodate the body width of a performer. There are specialized versions of the trapeze, such as the double horizontal trapeze in which a bar which is long enough to accommodate two performers is used and a third suspension line is added at the midpoint of the bar&#39;s length. Another specialized version is the double vertical trapeze in which one trapeze is suspended from another. However, until the present invention, the trapeze has been a little more than a periodic motion swing on which aerialists performed.  
       SUMMARY OF THE INVENTION  
       [0005]     The present invention adds a new feature to the prior art trapeze and to the ways in which a trapeze can be used. According to one aspect of the present invention, there is provided a compound trapeze consisting of a trapeze and a selectively engageable pivot interposed at preselected intermediate positions along the respective lengths of the suspension lines of the trapeze between their points of suspension and the trapeze bar. The selectively engageable pivot is referred to hereinafter and in the appended claims as a “secondary pivot.” The secondary pivot is used to selectively arrest the motion of the suspension lines between their points of suspension and the points at which the secondary pivot acts upon them so that the secondary pivot defines new pivot points for the portions of the suspension lines below the secondary pivot. When engaged, the secondary pivot interrupts the periodic motion of the trapeze midswing. This causes the trapeze bar and the performer holding onto it to angularly accelerate along an arc of suddenly shortened radius as both the effective length of the suspension lines and the period of swing of the trapeze are suddenly shortened by the restraining action of the secondary pivot. The angular acceleration gives the performer the opportunity to perform stunts which could not be performed under the constraints that the laws of physics impose on the periodic motion of an unrestrained trapeze.  
         [0006]     According to another aspect of the present invention, there is provided a secondary pivot for use with a trapeze.  
         [0007]     According to still another aspect of the present invention, there are provided methods of using a trapeze which include a step of restraining the periodic motion of the trapeze so that the performer experiences rotational acceleration.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     The criticality of the features and merits of the present invention will be better understood by reference to the attached drawings. It is to be understood, however, that the drawings are designed for the purpose of illustration only and not as a definition of the limits of the present invention.  
         [0009]      FIG. 1  is a schematic elevational front view of a prior art trapeze.  
         [0010]      FIG. 2  is a schematic perspective view of an embodiment of the present invention.  
         [0011]     FIGS.  3 A-C are schematic side elevational views illustrating the operation of the embodiment shown in  FIG. 2 .  
         [0012]      FIG. 3A  shows the embodiment at the instant in time when the performer is just about to swing out from the platform.  
         [0013]      FIG. 3B  shows the embodiment a short time later when the performer has reached a certain point in the swing at which the slack goes out of the restraining line.  
         [0014]      FIG. 3C  shows the embodiment a short time after that shown in  FIG. 3B .  
         [0015]      FIG. 4  schematically illustrates a plan view of a secondary pivot of another embodiment of the present invention in use taken at an elevation that is intermediate between the points of suspension of the trapeze suspension lines and the trapeze bar.  
         [0016]      FIG. 5  schematically illustrates a plan view of secondary pivot of another embodiment of the present invention in use taken at the same cross sectional height as  FIG. 4 .  
         [0017]      FIG. 6  schematically illustrates a plan view of a secondary pivot of still another embodiment of the present invention in use taken at the same elevation as  FIG. 4 .  
         [0018]      FIG. 7  schematically illustrates a plan view of a secondary pivot of yet another embodiment of the present invention in use taken at the same elevation as  FIG. 4 .  
         [0019]      FIG. 8  schematically illustrates a plan view of a secondary pivot of another embodiment of the present invention in use taken at the same elevation as  FIG. 4 .  
         [0020]      FIG. 9  schematically illustrates a side elevational view of an embodiment of the present invention in use wherein the length of the restraining line is dynamically adjustable. 
     
    
     DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0021]     In this section, some preferred embodiments of the present invention are described in detail sufficient for one skilled in the art to practice the present invention. It is to be understood, however, that the fact that a limited number of preferred embodiments are described herein does not in any way limit the scope of the present invention as set forth in the appended claims.  
         [0022]      FIG. 1  schematically shows a typical prior art trapeze. The trapeze  2  consists a bar  4  and two suspension lines  6 . The bar  4  is shown as having weights  8  at either end. Such weights  8  are often used to help stabilize the swing of the trapeze  2  when it is swinging without a performer. Each of the suspension lines  6  has a proximal end  10  from which the bar  4  is suspended and a distal end  12  from which the suspension line  6  itself is suspended.  
         [0023]      FIG. 2  shows a compound trapeze according to an embodiment of the present invention. The compound trapeze  14  is similar in many respects to the prior art trapeze  2  of  FIG. 1 . The compound trapeze  14  has a bar  16  which may optionally have weights  18  at its ends. The bar  16  is suspended near its ends by suspension lines  20 . Each of the suspension lines  20  has a proximal end  22  from which the bar  14  is suspended and a distal end  24  from which the suspension line  20  itself is suspended. Here the similarity with the prior art trapeze  2  ends. The compound trapeze  14  also includes a secondary pivot  26 . The secondary pivot  26  in this embodiment comprises an arresting bar  28  and a restraining line  30 . The arresting bar  28  is positionably attached to suspension lines  20  by fasteners  32 . The restraining line  30  is connected at its proximal end  34  to the center of the arresting bar  28  by a connector  36 . The restraining line  30  has a distal end  38  which is to be anchored so as to enable the restraining line  30  to interrupt the swing of the suspension lines  20  above the point of interaction P between the secondary pivot  26  and the suspension line  20 .  
         [0024]     FIGS.  3 A-C schematically illustrate the operation of compound trapeze  14 .  FIG. 3A  illustrates a point in time when the performer  40  is just about to jump off of box  42  on platform  44  that juts out from pole  46 . The performer  40  has just grasped bar  16 . The arresting bar  28  of secondary pivot  26  is attached to the suspension line  20  at point P and to the unshown companion suspension line at a corresponding point. The distal end  38  of restraining line  30  is anchored to pole  46  at a point A. The restraining line  30  has slack  48  at this point in time.  
         [0025]      FIG. 3B  illustrates a later point in time. The performer  40  has left the box  42  and swung out on the compound trapeze  14  along original arc  50  as suspension line  20  pivots about suspension point  52 . At this instant in time, restraining line  30  is just about to become taut. The periodic swinging motion of the performer  40  up until this instant is substantially the same as it would be for the prior art trapeze  2  shown illustrated in  FIG. 1 .  
         [0026]      FIG. 3C  illustrates an instant later. The restraining line  30  has become taut and has prevented suspension line  20  from continuing its pivoting about the suspension point  52 . This restraint causes the lower portion  54  of the suspension line  20  and the corresponding part of the unshown companion suspension line that are below point P to pivot about the arresting bar  28 . As a result, the performer  40  does not swing along the continuation of original arc  50 , but instead swings along a new arc  56 . Because the length of the lower portion  54  of the suspension line  20  and the corresponding portion of the unshown companion suspension line are shorter than the suspension lines full lengths, the period of the performer&#39;s swing is suddenly shortened and the performer  40  is angularly accelerated as his or her angular momentum is conserved. Thus, this embodiment of the present invention causes a change in motion that gives the performer the opportunity to perform stunts which could not be performed under the constraints that the laws of physics impose on the periodic motion of an unrestrained trapeze.  
         [0027]      FIG. 4  schematically illustrates a plan view of a secondary pivot of another embodiment of the present invention in use taken at an elevation that is intermediate between the points of suspension of the trapeze suspension lines and the trapeze bar. In this embodiment, the secondary pivot  58  comprises restraining line  60 , connecting link  62 , fork lines  64 , clamps  66 , and anchor  68 . The connecting link  62  connects the proximal end  70  of restraining line  60  to fork lines  64 . The fork lines  64  are positionably fastened to suspension lines  72  of the trapeze by clamps  66  at locations on the suspension lines  72  that are intermediate between their suspension points (not shown) and the trapeze bar (not shown). The distal end  74  of the restraining line  60  is anchored to the pole  76  by anchor  68 . The length of the restraining line  60  is selected so that the secondary pivot  58  interrupts the periodic motion of the trapeze at the desired point in its swing.  
         [0028]      FIG. 5  schematically illustrates a plan view of secondary pivot of still another embodiment of the present invention in use taken at the same elevation as  FIG. 4 . In this embodiment, the secondary pivot  78  comprises two restraining lines  80 . The proximal end  82  of each of the restraining lines  80  is positionably fastened to one of the suspension lines  84  of the trapeze by a clamp  86 . The distal end  88  of each restraining line  80  is anchored to one of the two poles  90  by being looped around it.  
         [0029]      FIG. 6  schematically illustrates a plan view of a secondary pivot of still another embodiment of the present invention in use taken at the same elevation as  FIG. 4 . In this embodiment, the secondary pivot  92  comprises two restraining lines  94  and an arresting bar  96 . The proximal ends  98  of the restraining lines  94  are attached by a connector  100  to the midpoint of arresting bar  96 . The distal ends  102  of the restraining lines  94  are anchored to poles  104 . The arresting bar  96  is positionably attached to suspension lines  106  by fasteners  108 .  
         [0030]      FIG. 7  schematically illustrates a plan view of a secondary pivot of yet another embodiment of the present invention in use taken at the same elevation as  FIG. 4 . In this embodiment, the secondary pivot  110  comprises two restraining lines  112 . Each of the restraining lines  112  has its proximal end  114  positionably attached to one of the suspension lines  116  by a fastener  118 . The distal end  120  of each of the restraining lines  112  connect to anchor connection  122  which itself is anchored to pole  124 .  
         [0031]      FIG. 8  schematically illustrates a plan view of a secondary pivot of another embodiment of the present invention in use taken at the same elevation as  FIG. 4 . In this embodiment, the secondary pivot  126  comprises two restraining lines  128 . Each of the restraining lines  128  is attached at its respective proximal end  130  to a connector  132  which connects it to the arresting bar  134 . The arresting bar  134  is positionably attached to each of the suspension lines  136  by a fastener  138 . The respective distal ends  140  of each of the restraining lines  128  are connected to anchor  142  which are anchored to pole  144 .  
         [0032]     In some embodiments of the present invention, the length of the restraining line or lines are dynamically adjustable. In these embodiments, the restraining line or lines are allowed to play out and/or play in as the performer swings on the trapeze. The restraining line or lines are made taut at a selected moment in the performance so as to interrupt the periodic motion of the trapeze.  FIG. 8  shows an example of such an embodiment.  
         [0033]     Referring to  FIG. 9 , there is depicted a schematic side view of a secondary pivot  146  in use which comprises restraining line  148  that is connected at its proximal end  150  to the midpoint of the arresting bar  152 . The arresting bar  152  is positionably attached to the suspension lines  154  (only one of which is shown) by fasteners  156  (only one of which is shown). The restraining line  148  runs over pulley  158 , which is anchored to pole  160 . The distal end  162  of the restraining line  148  is controlled handler  164 . As the performer  166  swings on the trapeze  168 , the handler  164  dynamically adjusts the length of the restraining line  148 . At a predetermined moment on the outward swing of the performer  166 , the handler  164  makes the restraining line  148  go taut, thus interrupting the periodic motion of the trapeze  168  and causing the performer  166  to rotationally accelerate.  
         [0034]     The secondary pivot of the present invention is not restricted to the embodiments described above, but includes all embodiments which comprise a mechanism that selectively restrains the periodic motion of a trapeze midswing so as to cause the performer on the bar of the trapeze to experience rotational acceleration as the suspension lines of the trapeze pivot about their points of interaction with the restraining mechanism.  
         [0035]     The point of interaction between the secondary pivot and the trapeze suspension lines is selected to provide the desired amount of angular acceleration to the performer. The closer the point of interaction is to the trapeze bar, the greater is the angular acceleration that the performer will experience. However, it is preferred that the point of interaction be kept above the performer&#39;s center of gravity.  
         [0036]     It is preferred that neither the performer nor the trapeze contacts the slack portion of a restraining line of a secondary pivot during use. Whether or not such contact may occur should be taken into consideration in selecting the anchor points of the restraining line or lines, the length of the restraining lines, and whether or not to dynamically adjust the restraining line length during use.  
         [0037]     The present invention also includes method embodiments. In such embodiments, a performer swings on a trapeze. At a preselected point in his or her swinging, the periodic motion of the trapeze is restrained at locations of the suspension lines that are intermediate between their points of suspension and the trapeze bar. The step of restraining causes the performer to experience a rotational acceleration which he or she optionally may use to perform stunts of his or her choosing. The point in the performer&#39;s swinging when the restraint is imposed is left to the discretion of the performer.  
         [0038]     While only a few embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that many changes and modifications may be made thereunto without departing from the spirit and scope of the present invention as described in the following claims.