Patent Publication Number: US-6220776-B1

Title: Joint for collapsible structures

Description:
RELATED APPLICATIONS 
     This application is a Continuation-In-Part of application Ser. No. 08/958,346 by Francis J. Reeves entitled Joint For Facilitating Fabrication of Collapsible Assemblies, filed on Oct. 27, 1997, which is a Continuation-In-Part of Ser. No. 08/288,309 filed Aug. 10, 1994 by Francis J. Reeves for a Collapsible Game Goals which is now U.S. Pat. No. 5,681,231 issued on Oct. 28, 1997. Both of these applications are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates to joints for use with collapsible structures. The invention has particular application to collapsible game goals. Games such as soccer, hockey and lacrosse require a goal incorporating a net. These goals are often large and not easily transportable. It is therefore inconvenient to use the same game goal to support games occurring at different times and at different locations. 
     The lack of mobility of the goals is a function of their size and the fact that they cannot be collapsed, folded or disassembled. Similar difficulties occur with other devices and assemblies where transportability is desirable, but the requirements of physical size and strength prevent such assemblies from being collapsed. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the invention to provide a assembly, such as a game goal, which is easily collapsible. 
     It is another object of the invention to provide a link for joining members of such a assembly. 
     These and other objects of the invention are accomplished by a joint according to the invention which facilitates collapsible structures. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is described with particularity with reference to the figures in which: 
     FIG. 1 illustrates a game goal incorporating joints and links according to the invention in the erect position ready for use; 
     FIG. 2 is a perspective view of the goal shown in FIG. 1 in an intermediate position transitioning from the erect position to the collapsed position; 
     FIG. 3 is a perspective view of the goal shown in FIGS. 1 and 2 in the fully collapsed position; 
     FIG. 4 illustrates a collapsible game goal with base members that can be inserted to the ground; 
     FIG. 5 illustrates an attachment between a net and the frame of a game goal according to the invention; 
     FIG. 6 illustrates structural members used in forming a joint according to the invention; 
     FIG. 7 illustrates a joint with a roll pin inserted therein; 
     FIG. 8 illustrates a joint with a lock wedge and heim joint inserted therein; 
     FIG. 9 illustrate the joint of FIG. 7 with a plug, lock slider and handle thereon; 
     FIG. 10 illustrate the joint of FIG. 9 with a movable member inserted thereon; 
     FIG. 11 gives a rear view of the joint shown in FIG. 10 with cover and upright attached; 
     FIG. 12 shows the joints of FIG. 10 in the fully engaged position; 
     FIG. 13 shows the corner joint the movable member in a disengaged position; 
     FIG. 14 is an exploded view of the assembly of the corner joint according to the invention; 
     FIG. 15 is another view of the corner view according to the invention; 
     FIG. 15 a  is a cross section of the joint shown in FIG. 15 taken through the lock wedge; 
     FIG. 15 b  is a cross section of the joint shown in FIG. 15 taken through the handle; 
     FIG. 16 is a cross section along line  6 — 6  in FIG. 15 showing a corner joint according to the invention assembled in the engaged position; 
     FIG. 17 illustrates a straight joint with a kick out member according to the invention in the engaged position; 
     FIG. 18 illustrates the joint of FIG. 17 in the disengaged position; 
     FIG. 19 is an exploded view of the assembly of the straight joint with kick out member according to the invention; 
     FIG. 20 is a cross sectional view along line D—D in FIG. 17 of the straight joint with kick out member according to the invention in the engaged position; 
     FIG. 21 illustrates an alternative configuration for the socket and attachable portions which may be used to form a corner joint according to the invention; 
     FIG. 22 shows still another alternative configuration using a corner pipe; 
     FIG. 23 illustrates that the mouth of the socket can be offset from the direction of the fixed member; 
     FIG. 24 illustrates a multiple socket joint according to the invention connecting three members; 
     FIG. 25 illustrates a point joint according to the invention; 
     FIG. 26 illustrates a lower corner joint according to the invention wherein the fixed member has a flat shape; 
     FIG. 26 a  illustrates a cross section of the flat fixed member shown in FIG. 26; 
     FIG. 27 illustrates a point joint using flat cross sectional members; 
     FIG. 28 illustrates a game goal in which three members come together at some corners; 
     FIG. 29 illustrates another variation on the socket according to the invention wherein the cross section is not circular; 
     FIG. 30 a  illustrates a shoulder strap according to the invention; 
     FIG. 30 b  illustrates the shoulder strap of FIG. 30 a  in use to carry a collapsed structure; 
     FIG. 31 illustrates a configuration according to the invention which allows a collapsed structure to be moved on wheels; 
     FIG. 32 represents an alternative structure according to the invention which allows a collapsed structure to be transported on wheels. 
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     FIG. 1 illustrates a structure, such as a game goal  101  which incorporates joints and links according to the invention. FIG. 1 is shown with game goal  101  in an erect position. The goal  101  in FIG. 1 has corner joint  103 , straight joint  105  and point joint  107 , each of which facilitates collapsing of the structure. As discussed further herein, corner joints  103  can be formed, for example, by welding two straight parts together. Also shown in FIG. 101 are dog legs  109  in the portions of the structure which contact the ground. Dog legs  109  are used, for example, in a lacrosse goal, when the base or ground frame members  111  comprise ground pipes. As used herein the term “dog leg” is any pipe with a bend. The dog leg is useful for preventing a ball from deflecting off the round pipe back into the playing field, making it difficult to determine whether a goal was actually scored. As discussed further herein, where the base or ground frame members  111  are flat bars, as permitted under the rules of National College Athletic Association (NCAA), dog legs  109  are not necessary because balls are much less likely to deflect off a flat bar protruding only a short distance, e.g., one half inch, above the ground. The dog leg ground members as shown in FIG. 1 also meet NCAA specifications. 
     As previously noted, FIG. 1 shows a goal  101  with the net attached in the fully erect position. Joints  103 ,  105  and  107  are also shown in the preferable orientation of their sockets. As further discussed herein, however, it will be know to those of ordinary skill that other orientations could be employed. Thus, the invention is not limited to the particular configuration or orientation of joints shown in FIG. 1, but may included other configurations and orientations as well. 
     FIG. 2 is a perspective view of the goal shown in FIG. 1 in an intermediate position transitioning from the erect position, shown with the designations “a” for the members and joints, to the collapsed position, with the intermediate positions of the joints and members shown as “b.” Arrows  113 ,  115 ,  117 ,  119 ,  121  and  123  indicate the direction of motion of the members as this particular structure transitions from the erect position to the collapsed position. Those of ordinary skill will recognize that other structures may use the joints according to the invention to form collapsing structures other than that shown herein. However, the collapsing structure in FIG. 2 is believed to be an optimum collapsing structure for a lacrosse goal. 
     FIG. 3 illustrates the lacrosse goal shown in FIGS. 1 and 2 in the fully collapsed position. FIG. 3 illustrates the position of ground frame members  111 , cross bar members  127  and uprights  125  along with the individual joints  103 ,  105  and  107  when the game goal is collapsed. An important feature of the invention illustrated in FIG. 3 with respect to a collapsible structure is that the invention provides a coordinated twisting of members so that all joints can be twisted to work together without binding, as discussed further herein. 
     FIG. 4 illustrates a collapsible game goal in accordance with the invention wherein the base portion of the goal can be inserted into the ground. In FIG. 4, vertical frame members  125  have an extension  129  which can be inserted into the ground and extends below the ground level. Net  131 , which is fastened to the vertical frame members  125  and the cross bars frame members  127 , as well as corner joints  103 , is fastened to the ground using one or more members  133 , as shown in FIG.  4 . Net securing members  133  are shown shaped as an inverted letter “J”, but could have any convenient shape which allows insertion of the member into the ground such that it encloses the edge  135  of the net  131  where it intersects the ground. Thus, an inverted “V” or an inverted “U” or other similar shape could be used for member  133 . The configuration shown in FIG. 4 is advantageous in that it requires fewer corner joints  103 , avoids the need for point joint  107  and eliminates the need for base members  111 . As a result, the configuration in FIG. 4 is lighter and even more portable and meets NCAA specifications. 
     FIG. 5 illustrates an improved attachment between the net  131  and the frame of a game goal. The attachment shown in FIG. 5 can be used whether the game goal is of the collapsible and portable configuration or is of the fixed type. According to the invention, net  131  has a hem  137  with a rod  139  inserted therein. Conventional goals do not have the rod in the hem. The rod can be of any suitable ridged or semi-ridged materials such as metal, fiberglass or plastic and may be hollow or solid. FIG. 5 shows the intersection of the net with a vertical frame member  125  and a base frame member  111  at corner joint  103 . However, those of ordinary skill will recognize that the same principles apply around the entire structure. As shown in FIG. 5, the members, such as vertical frame members  125 , base frame member  111  and corner joint  103  has holes  140  and  142  drilled therein. A zip tie, such as that used to bundle electrical wires together, or other fastener  144  is passed through holes  140  and  142 , around hem  137  with rod  139  therein. This holds the net  131  close to the frame wherever the rod is inserted in the hem of the net. In order to prevent snagging of the net when the goal is being changed from a collapsed to an erect position, or at various other times, one of the holes e.g.  141 , can be made slightly larger than hole  142 , as shown in FIG.  5 . This allows insertion of the buckle  146  of zip tie  144  into hole  141  so that a portion of the zip tie buckle is concealed below the outer diameter. This could also be accomplished by countersinking the hole or holes for the fasteners of the frame member. As a result, the net cannot snag on the net fastener. By using the rigid member  139  in the hem  137 , it is not necessary to use a large number of zip tie connections to the frame members. Although the frames can be manufactured with any number of holes to accommodate net fasteners, it will not be necessary to use a net fastener in each and every hole along the perimeter of the net, as is done in conventional goals. One need only attach the net  131  to the frame members with as many net fasteners as is necessary to maintain the net in good connection with the frame structure. 
     One need only use a sufficient number of net fasteners to fasten the rod in the hem of the net to the frame such that a ball, puck or other object used in a game cannot pass between the hem of the net and the frame member. 
     For the left upright  125  of the goal in FIG. 1, fastening the rod  139  in the hem  137  of net  131  with four net fasteners makes it impossible for a ball to pass between the net and frame member  125 . Other goals of other configurations may require fewer or greater number of fasteners to prevent a ball from passing between a net and the frame member. 
     The net attachment according to the invention herein can reduce the time required for net replacement and reduce manufacturing and assembly costs, because fewer fasteners are needed then in conventional goals. Positioning the net fastener holes away from the opening in the front of the goal allows an aesthetically pleasing attachment of the frame to the net and leaves the opening of the goal free of net fasteners. 
     An alternative to the net fasteners shown in FIG. 5 is to use a single hole with a generally u-shaped net fastener as disclosed in application Ser. No. 08/288,309 previously incorporated herein by reference. The net remains attached at all times to the frame whether in the erect or collapsed position. 
     FIG. 6 illustrates some of the structural members used in forming a corner joint  103 . In FIG. 6 straight members  601  is connected to hollow pipe member  603  having a socket portion  605  therein. Member  601  is connected to portion  603  at joint  607  using a suitable connection technique. Preferably, if the member  601  and member  603  are metal, they are connected by welding at joints  607 . To achieve a 90 degree elbow shape, the connection is preferably made with a 45° mitre on the ends of members  601  and  603 . However, it will be known that other shapes and other angles can be used to achieve different angular relationships between members  601  and  603 . As shown in FIG. 6, member  603  having socket  605  therein preferably has holes  609  and holes  611 , which are discussed further herein. As shown at  613  in FIG. 6, socket portion  605  preferably has a mouth portion which is an opening for example between points A and B which is smaller than the inner diameter of the pipe  603  in which the socket portion is formed. For example, the mouth of the socket portion could measure 1.600 inches between points A and B, while the inside diameter of the pipe is 1.615 inches. The purpose of this difference in dimension is to allow the socket portion to provide a snap fit to a member which is eventually pressed through the socket mouth. The snap fit is accomplished as a result of flexing in the material the socket is made of. 
     FIG. 7 illustrates that the socket portion  605  with a roll pin  701  inserted into the holes  609 . The roll pin  701  has a gap  703  along the length of the pin so that the roll pin can be pressed in and inserted into the holes  609 . The spring effect of releasing the compression of the roll pin after insertion into holes  609  maintains the roll pin  701  in the holes  609 , thereby keeping the roll pin in the socket portion  605 . 
     FIG. 8 illustrates roll pin  701  with a rod end ball joint  801 , known as a heim joint thereon. Those of ordinary skill will recognize that a member attached to a rod end ball joint or heim joint will experience multiple degrees of freedom of motion, which are allowed by a heim joint. The function of the heim joint is discussed in more detail herein. During the assembly process, the heim joint is positioned on roll pin  701  at a position on the roll pin where the rotation of the heim joint is to occur. The position can be set for example using spacers which are removed after the heim joint and roll pin are positioned into the socket  605 . After the heim joint is positioned in the desired location within socket  605 , the roll pin  701  is pressed into the holes  609  and simultaneously in the hole in the heim joint. As previously noted, roll pin  701  has gap  703  along its length, which expands to hold the roll pin in the holes  609  of socket portion  605 . The expansion of the roll pin by its spring force also serves to maintain the heim joint  801  in its desired position. At that time, if spacers have been used to position the heim joint on the roll pin, the spacers can be removed, since the position of the heim joint is now fixed. The heim joint has rod  803 , which can be threaded into a plug which holds the heim joint into a movable member (not shown in FIG.  8 ), as discussed further herein. 
     FIG. 8 also illustrates lock wedge  805  attached in holes  611  in socket portion  605 . As discussed further herein lock wedge  805  engages a lock slider thereby further assuring the movable member remains in place when the frame is in the erect position. Surface  807  which contacts socket portion  603  has a slant or taper, e.g., 1.50, along its length thereby forming a wedge. 
     FIG. 9 illustrates rod  803  of heim joint  801  inserted into plug  901 . As discussed further herein and shown in FIG. 10, plug  901  will allow a movable member  125   a  to be connected to the heim joint. FIG. 9 also shows a lock slider  903 . Lock slider  903  has a gap  903  therein, as shown. As further discussed herein, lock slider  905  can be positioned slidably to intersect lock wedge  805  in order to lock the movable member into the socket portion  605 . As previously noted, socket portion  605  is preferably formed such that the movable member has a snap fit with the socket portion  605 . Lock wedge  805  assures that the movable member remains in the socket portion in the erect position. Manipulation of lock slider  903  is facilitated through handle  907 . 
     FIG. 9 also shows a P-clip  909 . The P-clip includes a protrusion, as shown at  909 , which creates drag between the lock slider and a pipe forming the movable member as the P-clip slides therein. 
     The P-clip is mounted on the inside of the lock slider  909  as to partially protrude past the outside diameter of the lock slider. When the lock slider is inserted into a movable member this protrusion creates a spring like resistance which crates drag in the lock slider. This drag helps to prevent unlocking of the joint during normal use. 
     FIG. 10 shows the P-clip  909 , lock slider  903  and plug  901  all inserted into a pipe forming movable member  125   a.  FIG. 10 is a front view and illustrates that the movable member  125   a  has screw holes  1005  and  1003  therein which are used for fastening a cover to the movable member. As further discussed herein, hole  1003  has a screw inserted therein which threads into plug  901 , thereby securing the movable member  125   a  to the plug which has threads and holds the heim joint  801 . Screw hole  1005  accommodates a screw which keeps the cover in place and does not protrude into the inner diameter of the movable member. It should be noted that handle  907  is inserted into the lock slider  903  after the lock slider, plug  901  and P-clip  909  are inserted into the movable member. In this way, handle  907 , which can only move in the space provided by window  1001 , controls the position of lock slider  905  inside movable member  125   a.    
     FIG. 11 illustrates a rear view of the connection between the movable member  125   a  and the socket portion  605  of the joint according to the invention. Screw holes  611  illustrate where lock wedge  805  is fastened to the inside portion of socket portion  605 . Cover  1101  on the movable member has several purposes. The first purpose is to provide a uniform outer diameter for the movable member  125   a  when the movable member is inserted into the socket portion  605  and frame member  125  is attached thereon. The cover portion  1101  also serves to align the pipe forming movable member  125   a  into the engaged position in the socket member  605 . Thus the cover portion helps prevent the movable member from becoming misaligned and forces the movable member into a smooth engagement with the socket portion  605 . FIG. 11 also illustrates a window  1103  through which lock wedge  805  protrudes into the inner diameter of the movable member in the engaged position. When the movable member is placed completely into the socket portion, the user simply slides lock slider  903  over lock wedge  805  by moving lock handle  907  within the range permitted by window  1001 . This wedging effectively locks the movable member to the socket using internal mechanisms. 
     FIG. 12 shows the joint assembled with the movable member  125  in the fully erect position. As previously noted, bottom screw  1003  and top screw  1005  serve to attach the cover plate  1101 . In addition, bottom screw  1003  protrudes into the plug  901  of the heim joint  801  thus affixing the movable member to the plug. Screws  1003  and  1005  are countersunk so as not to protrude beyond the outer diameter of the frame member. In addition, a screw  10005  that is placed is of a length such that it does not protrude into the inner diameter of the movable member  125   a  so that there is complete clearance for movement of lock slider  903  in the inner diameter of the movable member. Frame member  125  fits over movable  125   a,  so that frame member  125  moves with movable member  125   a.  Frame member  125  and movable member  125   a  may according to the invention be integrated into one piece. 
     FIG. 13 shows the movable member  125   a  in a disengaged position, which would be used for collapsing the assembly. As previously noted herein, in order to efficiently collapsed such an assembly it is important to provide some twisting of the movable member. According to the present invention, the movable member can twist as a result of the movable member&#39;s connection to the plug  901  and the heim joint  801 . Plug  901  is rotatably attached via a screw thread to rod  803  of the heim joint  801 . Thus, as the movable member is disengaged and collapsed, it is free to rotate because it is fixedly attached to the plug which is free to turn on the threaded attachment of the plug  901  to the rod  803  of the heim joint  801 . This arrangement provides an added degree of motion, allowing the apparatus to be collapsed in the most efficient manner. On the other hand, when the apparatus is assembled into the erect position, the fit between the cover  1101  and the member  603  with slot  605  therein causes the movable member to rotate in the same manner into a proper position to fit into the slot portion  605 . As a result, the assembly according to the invention provides an efficient way to erect and collapse a structure using a gapped or slotted member  603  and an ungapped member. 
     FIG. 14 is an exploded view of the assembly according to the invention as just described. As clarified in FIG. 14, frame member  125  attaches over pipe  125   a  which moves in and out of the socket portion  605 . Thus movable member  125   a  has an outer diameter which permits frame member  125  to slide over the movable member. 
     FIG. 15 is another view according to the invention of a corner joint. FIG. 15 a  is a cross section taken through lock wedge  805 . FIG. 15 b  is a cross section seen through handle  907 . As illustrated in FIG. 15 b,  handle  907  is fastened to lock slide  903  using screw  1501  which engages hole  1503  and lock slider  903 . These cross sections illustrate that a plurality of structural members (in this case, three structural members) are configured such that cover portion  1101  and socket portion  603  form a smooth outer diameter. Other details of the construction consistent with the previous figures are shown in FIGS. 15,  15   a  and  15   b.    
     FIG. 16 is a cross section showing a corner joint assembled in the engaged position. In particular, FIG. 16 is an interior view of the corner joint in the assembled and engaged position. FIG. 16 illustrates how P-clip  909  slides along the interior of pipe  125   a  that forms the movable member of the joint. P-clip  909  thus creates drag which affects the motion of lock slider  903 , FIG.  16 . It also illustrates the connection between rod  803  of heim joint  801  and plug  901 . As previously discussed, screw  1005  extends through cover  1101  and pipe  125   a  into plug  901 , while screw  1003  extends through cover  1101  into pipe  125   a,  but does not extend beyond the inner diameter of pipe  125   a.  This allows free range of motion of the lock slider  903  using handle  907 . FIG. 16 also shows that lock slider  903  has an angle cut  1601  on its backside to allow screwdriver clearance when installing a bolt (not shown) to fasten P-clip  909 . Lock slider  903  also has a beveled edge  1603  on its forward end which facilitates its engagement and motion into the lock wedge  805 . Only edge  1603  is beveled. The remaining portion  1605  of lock slider  903  intersecting lock wedge  805  has no such bevel. 
     FIG. 17 illustrates a straight joint according to the invention, for example, as would be used as a joint  105  to collapse frame members  127  of the cross bar shown in FIG.  1 . On one end the straight joint connects to frame member  127  through a movable member formed by pipe  127   a.  FIG. 1 shows the joint in the assembled and engaged position. Straight joint  105  has substantially the same structure as the corner joint  103  discussed previously herein. Straight joint  105  has a heim joint  801  with a rod  803  engaging plug  901 . The remaining portion of the structure of the joint is the same as that for the corner joint except for incorporation of a kick out member  1703 . 
     The straight joint  105  shown in FIG. 17 also has a kick out member  1703  which pivots on a dowel pin  1705 . The kick out member is preferably connected to the dowel pin using set screw  1707  which holds the dowel pin in holes  1709 . The dowel pin is preferable to a gapped roll pin in this application in order to avoid binding, squeaking and wearing out at points where the dowel pin is attached to the socket portion  1701 . 
     FIG. 18 provides a more detailed view of the straight joint  105  in the disengaged position. FIG. 18 shows how a movable member connected to the kick out member is free to move outside the socket. Heim joint  801  rotates on roll pin  701  inserted in holes  1711  and kick out member  1703 . As illustrated in both FIGS. 17 and 18 kick out member  1703  has a generally U-shaped construction with the roll pin  701  being placed between the upright portions of the U to internally secure the heim joint to the kick out member and to allow the heim joint to move therein. The end positions  1713  and  1715  of the kick out member  1703 , however, control how far movable member  127   a  connected to heim joint  801  through plug  901  can rotate. For example, as shown in FIG. 18, the shape of portions  1715  allows clearance for the heim joint to move so that the assembly attached to the heim joint including the cover plate  1101  on movable portion  127   a  does not contact kick out member  1715 . However, the shape of end portion  1713  of kick out member  1703  prevents movement in the opposite direction, such that member  127   a  can move only about 90° before coming into contact with surface  1713  of kick out member  17003  preventing further rotation on roll pin  701 . Member  127   a  then inserts into the socket portion  1701  as a result of the rotation of the kick out member  1703  on dowel pin  1705 . As previously discussed, heim joint  801  has a rod  803  which is connected to plug  901  using a threaded connection. This allows the movable member  127   a  to rotationally turn thereby forming a good fit with the slotted portion  1701  of the joint. The nose  1717  of the kick out member is tapered, thereby allowing the kick out member to clear the inside diameter of the socket when it pivots within the socket. This allows the pipe  127   a  a greater degree of motion, nominally 180°, outside the socket rather than 90°. 
     FIG. 19 is an exploded view of the cross bar joint. In this figure, holes  1721  are shown in kick out member  1703  to accommodate insertion of roll pin  701  having gap  703 . Frame member  127  is inserted over movable member  127   a.  Member  127  according to the invention could be integrally formed within movable member  127   a  as one piece, just as previously mentioned with respect to members  125  and  125   a.    
     FIG. 20 illustrates a cross section of straight joint  105  in the engaged position. FIG. 20 clearly shows a hole for a set screw  1707  used to hold dowel pin  1705  inside hole  1709  to allow rotation of kick out piece  1703 . As can clearly be seen in FIG. 20, the portions of straight joint  105  are the same as those of corner joint  103  beginning with the connection of rod  803  of heim joint  801  to plug  901 . A significant difference between joints  103  and  105  is the addition of the kick out member  1703  and the connections in joints  105  to kick out member  1703 . FIG. 20 shows the abutment of kick out member surface  1713  to plug  901  and movable member  127   a.  The principles of the invention for corner and straight joints remain the same. 
     FIG. 21 illustrates an alternative configuration for the socket and attachable portions of the corner joint  103 . FIG. 21 shows member  603  having socket portion  605  therein, as shown in FIG.  6 . It will be understood that all of the connections to the socket portion for the movable portion of the joint are the same as those previously discussed herein. Unlike FIG. 6, however, FIG. 21 shows member  2101  extending at an angle from the bottom portion of member  603  in the drawing. In this configuration one need not weld on member  601  to form joints  607 . Instead member  2101  can be male or female threaded or not and a member can be attached thereto to provided the fixed portion. Thus, a pipe could be screwed on to member  2101  or a pipe could be attached to member  2101  through a compression fitting, gluing, or some other means. As a result, the joint  2100  shown in FIG. 21 can be manufactured separately from the overall collapsible structure. This ability to manufacture the joint separately may have advantages in certain applications. 
     FIG. 22 shows an alternative joint  2200 , which is another derivative of the joints according to the invention. In FIG. 22 member  603   b  is formed to intersect with a corner pipe  2201 . The corner pipe  2201  then attaches to fixed member  601 . In this configuration the socket joint  603   b  is attached to the corner  2201  and the corner is attached to a stationary member  601 . As in FIG. 21, the connection between the members and the corner piece  2201  can be threaded with the male and female portions of the threads configured as advantageous for a particular application. Alternatively, connections to the corner member  2201  can be of other types, such as compression fittings by gluing. 
     FIG. 23 is a view of upper corner joint  103  from inside the goal shown in FIG.  1 . The mouth of the socket portion  605  can be directionally oriented in any desired direction. For example, in the view shown in FIG. 23 the mouth of the socket portion is directionally oriented offset about 30° from an axis along the length of fixed member  125 . In addition, the mouth of this socket portion of this upper corner and the socket portion of the other upper corner are aligned or open towards the point joint rather than straight down. In this particular application of a lacrosse goal, such orientation facilitates collapsing the goal into a conveniently portable configuration. According to the invention, socket portion  605  can be positioned at any location around the circumference of the joint in order to achieve the desired result of in the collapsed or erected state. 
     As discussed herein, the multiple degrees of freedom provided by the joint allows twisting to facilitate collapsing of the frame. Referring again to FIG. 3, it is clear that in the collapsed position the covers on the lower corner joints  103  face each other. In the erect position as shown in FIG. 1, these same covers point rearward perpendicular to the plane of the opening in the goal. This change in the directional or orientation of the covers occurs as a result of the twisting. 
     It should also be noted that the lock slider is discussed herein in a first configuration oriented to move along the axis of the length of the movable member. Those of ordinary skill will recognize that the lock slider could also be configured in a second orientation to rotate to within the movable member. Both configurations use the inner diameter of the movable member to guide the motion of the lock slider. In the first orientation, the window  1103  is offset along the length of the movable member from window  1001  as shown in FIGS. 11 and 13. In the second configuration, the window  1103  would be positioned directly opposite or behind window  1001 . 
     FIG. 24 illustrates a three bar joint  2400  with two sockets  2401  and  2403  and one stationary member  2405 . In the example shown in FIG. 24, each socket  2401  and  2403  is configured as a corner socket. Those of ordinary skill will recognize that any number of such sockets and fixed members can be formed into a single joint. In addition, any combination of sockets and stationary members can be used. Even when multiple socket joints are used, the directional orientation of the socket mouth can be offset from the axis along the length of the frame member, e.g.  2405 . 
     FIG. 25 illustrates a point joint  107  according to the invention. Point joint  107  has a bracket  2501  with holes  2503  and  2505 . Inserted into holes  2503  and  2505  are roll pins  2507  and  2509 , respectively. Each roll pin, which is substantially the same as roll pins  701  having a gap  703 , as previously discussed herein, extends through holes in the members  111 . The size of hole  2303  and  2305  is substantially the same as the size of the roll pin  2307  and  2309 . However, the holes in members  111  through which the roll pins pass have a slightly larger diameter, so that members  111  can pivot freely on the roll pins without interference. Members  111  in FIG. 1 are shown as ground members for the lacrosse goal illustrated in that figure. However, the point joint shown in FIG. 25 can be used in other applications. Holes  2511  are used to fasten the net to the point joint. 
     FIG. 26 shows another variation of a joint according to the invention. In FIG. 26 member  603   c  has a slotted portion  605  to accommodate movable member  125   a.  In this case, unlike the previous configurations, member  603   c  intersects a flat member  2601 . A cross section of member  2601  is shown in FIG. 26 a.  As illustrated in FIG. 26 a,  the cross section of member  2601  is substantially rectangular. Of course a square or other flat configuration could also be used. A flat member such as member  2601  may be useful in certain game goals where NCAA specifications permit. For example, NCAA specifications permit use of flat ground members in the cross goals and is especially useful when playing artificial surfaces. Member  2601  can be attached to member  603   c  by welding, bolting, threaded connection, insertion and gluing or other fastening means. Those of ordinary skill will recognize that member  2601  could be of any other shape while still being within the scope of the invention. For example, member  2601  could have a triangular, hexangular or octagonal cross section, without departing from the scope or the intent of the invention. 
     FIG. 27 illustrates a point joint  2700  constructed using a sharp angle bracket  2701  and flat members  2702 . As illustrated in FIG. 27, the connection between the holes and the roll pins would follow the same design consideration as that given in FIG. 25 for the roll point joint connecting to rounded members. Similarly, the net could be attached at holes  2511 . 
     FIG. 28 shows an example of a game goal in which three members come together at some of the corners. As previously discussed herein, joints according to the invention can encompass any number of such corners and could be used to form a collapsible goal where more than two frame members intersect. 
     FIG. 29 is a further variation on the joints shown in FIG.  21 . FIG. 29 differs from FIG. 21 in that the joint shown in FIG. 29 has sharp edges. In FIG. 29, member  2901  intersects with the fixed member  2902 . Member  2903  having a slotted portion  2905  therein is configured for insertion of the movable member. Wedge lock  2907  is placed on the rear wall  2909  of slotted portion  2905 . As shown by way of illustration in FIG. 29 a  movable member rotates using a heim joint on roll pin  701  having gap  703  therein. 
     As will be recognized by those of ordinary skill, other configurations of joints having various external shapes can be accommodative within the scope of the invention. All joint structures according to the invention fit within the outer diameter specification sports goals set by the NCAA. 
     The snap fit between the movable members and their corresponding joint sockets holds the movable members in place in the absence of engagement of the lock slider with the locks wedge. When erecting a goal or other structure, the structure stays upright allowing one to lock the frame members in place in any order. When collapsing a goal or other structure, the snap fit prevents the structure from falling over when the lock wedges are disengaged. The snap fit forces one to intentionally collapse the structure when desired. This provides a safety advantage. 
     FIG. 30 a  illustrates a shoulder strap  3000  according to the invention which can be used in carrying a goal such as a lacrosse goal. Shoulder strap has a strap or cord  3001  and end members  3003  and  3005 . Strap  3001  can be fixedly or removably attached to the end members. The end members  3003  and  3005  each have a buckle  3007  and  3009  which, when closed results in the end member having a generally circular configuration, which can be used to enclose portions of the goal to facilitate carrying. FIG. 30 b  shows the shoulder strap connected to the end members in use to carry the goal in the collapsed configuration shown in FIG.  3 . 
     FIG. 31 shows another means of transporting the collapsed goal of FIG.  3 . In FIG. 31 the goal is shown with slots  3101  in the base corner joints  103 . The slots accommodate an axle  3103  to which wheels  3105  are attached. Point joint  107  can then be used to tow the collapsed assembly on wheels. Pins stick up from the axle to hold it in place. 
     FIG. 32 shows still another configuration for towing a collapsed goal according to the invention. In this configuration the point joint  107  has attached thereto a clip on assembly  3201  with an axle  3202  and wheels  3205 . The handle strap  3209  loops over the lock wedges  805  inside the slotted portions  605  of the corner joints  103 . Alternatively, the handle  3207  is inserted into holes in the slot portions of joints  103  at the base of the collapsed assembly. The handle and wheels are then used to tow the goal. In the arrangement in FIG. 32, the weight of the goal pushes down onto the dog leg portion of axle  3207 , forcing sheer on the pins  3209  which keep the wheels on the axle. 
     While several embodiments of the invention have been described, it will be understood that it is capable of further modifications. For example, the goals described herein use a net the means for receiving a projectile. It will be understood that a net is used to allow spectators and unobstructed view of the game. Alternatively, a solid cloth could be used in place of a net. Such a cloth could be clear, opaque or any combination thereof. Similarly, a projectile receiving means could be made of portions of a solid cloth or any other composition approximating the functionality of a net or webbing. Thus this application is intended to cover any variations, uses or additions of the invention, following in general the principals of the invention and including such departures from the disclosure as to come within the knowledge or a customary practice in the art to which invention pertains, and as may be applied to the essential features herein before set forth and falling within the scope of the invention or the limits of the appended claims. It will be further recognized that the particular shape of the joint whether it be rounded, square, rectangular, hexagonal, octagonal, triangular, or any other shape are all within the scope of the invention. It will be further recognized that joints according to the invention can be constructed to be oriented in any direction and with any number elements. For example, a corner joint can have two or more elements with any combination of movable and fixed members.