Abstract:
A collapsible goal post includes a lower support extending from a playing field; a upper support having a first end and a second end, and a pivot assembly attaching the first end of the upper support to the lower support; an upper assembly comprising two uprights and a crossbar having two ends. The crossbar is attached to the second end of the support at about the midpoint of the crossbar. One of the two uprights is attached to each end of the crossbar. The upper support is configured to pivot about the pivot point assembly to move the upright assembly from a raised position to a lowered position. The two uprights are substantially perpendicular to the playing field in the raised position, and are substantially parallel to and contacting the playing field in the lowered position while the upper assembly and upper support remain attached to the lower support. In another embodiment, the goal post includes a hydraulic cylinder system coupled to the upper support and the lower support to hinder a rate of pivoting of the goal post about the pivot assembly.

Description:
BACKGROUND 
       [0001]    This invention relates to a collapsible goal post that is suitable for use in American football. 
         [0002]    A goal post in American football consists of a base connected to the playing field, a support attached to the base, a crossbar extending perpendicular from the support and parallel to the playing field, and an upright extending from either end of the crossbar. After many sporting games, it is common for fans and spectators to rush onto the field. In American football games in particular, spectators or vandals often climb onto and hang from the crossbar, support or other parts of the goal posts. Spectators falling from the goal posts may be injured or killed, or injuries or death can results from climbing spectators falling onto other spectators, players, officials, staff and others on the field. The goal posts are sometimes torn down by the spectators, which can also lead to injury and death to players, officials, staff, spectators and others on the field. It is also costly, time-consuming and otherwise bothersome to replace torn-down goalposts. 
         [0003]    U.S. Pat. No. 6,945,885 describes an articulated football goal post having a crossbar and uprights that that can be pivoted to a raised game position and lowered to a second position. However, since the uprights are substantially vertical in both the raised and lowered positions, the uprights can still be climbed or torn down by spectators or vandals. 
         [0004]    U.S. Pat. No. 7,252,605 describes an articulated football goal post having a crossbar and uprights that can be pivoted to a raised game position and lowered to a second position. In the second position, the uprights are substantially parallel to but suspended above the playing field. The second lowered position facilitates detachment of the crossbar and uprights. Although the detachment of the crossbar and uprights may prevent damage, the detachment process may be too slow to allow for complete detachment before the spectators rush onto the field. If removed by spectators or vandals, the uprights themselves may be moved, brandished, or otherwise handled in a manner that could cause injury or death to those on the field or in the area of the field. Furthermore, the detached crossbar and uprights must be completely removed from the field to prevent theft. The additional removal step is also time-consuming, and possibly even dangerous in a crowded situation. 
       SUMMARY 
       [0005]    One embodiment of the present invention is directed toward a goal post for American football that is quickly, easily and safely lowered to the ground, making it impossible to climb on or otherwise forcibly tear down the goal post. 
         [0006]    A goal post having a hinged pivot point is held in an upright position by a clevis pin locking device. To collapse the goal post, the pivot point is unlocked and gravity pulls the crossbar and uprights into a lowered position, wherein the crossbar and uprights are substantially parallel to and resting on the playing field. 
         [0007]    In another embodiment, one or more hydraulic cylinders, for example double-acting hydraulic cylinders, regulate the speed of the lowering. The hydraulic cylinder may be situated on either side of the pivot point. The hydraulic cylinder allows the travel speed from the raised position to the lowered position to be adjustable. A pump connected to the hydraulic cylinder allows the goal post to be raised by the hydraulic cylinder. The one or more hydraulic cylinders may be removable in either the raised or lowered positions 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    Further developments of the invention will stand out from a description of embodiments with reference to the drawings. 
           [0009]      FIG. 1  shows a front schematic view of an embodiment of a goal post in a raised position. 
           [0010]      FIG. 2A  shows a side schematic view of the goal post shown in  FIG. 1  in the raised position. 
           [0011]      FIG. 2B  shows a side schematic view of the goal post shown in  FIG. 1  in a lowered position. 
           [0012]      FIG. 3A  is a close-up side schematic view of the goal post shown in  FIG. 1  in the raised position. 
           [0013]      FIG. 3B  is a close-up side schematic view of the goal post shown in  FIG. 1  in the lowered position. 
           [0014]      FIG. 4  is a close-up rear schematic view of the goal post shown in  FIG. 1  in the raised position. 
           [0015]      FIG. 5  is a schematic of the hydraulic system for the hydraulic cylinder. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    With regard to  FIGS. 1 ,  2 A and  2 B, a goal post  1  includes a base portion assembly  100 , an upper portion assembly  200 , a pivot point assembly  300  connecting the base portion assembly  100  to the upper portion assembly  200 , and a hydraulic assembly  400 . The goal post  1  is pivotable from a raised position to a lowered position. 
         [0017]    The base portion assembly  100  includes a lower support  110  and optionally a padding  180 . A bottom portion  118  of the lower support  110  installed below the plane of a playing field  10  and attaches to an anchor assembly (not shown), separate from the base portion assembly  100 . The anchor assembly may include hardware to secure the goal post  1  to the playing field  10 . The lower support  110  extends substantially perpendicular from the playing field  10 . A top portion  112  of the lower support  110  includes a beveled portion  112   a  and a horizontal portion  112   b.  The horizontal portion  112   b  is substantially perpendicular to the longitudinal axis of the lower support  110 . The beveled portion  112   a  is at an angle to the horizontal portion  112   b.  The top portion  112  of the lower support  110  further includes parts of the pivot point assembly  300 , which is described below. 
         [0018]    The padding  180  covers the base portion assembly  100  in a circumferential direction from the playing field  10  to at least approximately 6 feet above the playing field  10 . In one embodiment, the padding  180  is approximately 30 inches in diameter. 
         [0019]    The upper portion assembly  200  includes a curved cylindrical support  210 , a cylindrical crossbar  240  and two cylindrical uprights  260 . 
         [0020]    The curved support  210  includes a first end  212  and a second end  214 . The first end  212  of the curved support  210  includes a beveled portion  212   a  and a flat portion  212   b.  The curved support  210  is attached to the lower support  110  by the pivot point assembly  300  at the first end  212 . The second end  214  includes an open end forming a cavity  214   a.  The curved support  210  is curved such that the axis of the first end  212  and the axis of the second end  214  are substantially perpendicular. 
         [0021]    The crossbar  240  has two ends  244 , two end shanks  245 , a top  246 , a midpoint  242  and a midpoint shank  243 . Each end shank  245  is a cylindrical segment smaller in diameter than and coaxial with the upright  260 , and located near each of the ends  244 . In one embodiment, each end shank  245  is welded to the crossbar  240 . Each end shank  245  is substantially perpendicular to the longitudinal axis of the crossbar  240 . The midpoint shank  243  is a cylindrical segment at about the midpoint  242  of the crossbar and extends substantially perpendicular to both the longitudinal axis of the crossbar and each of the two cavities  245 . The second end  214  of the curved support  210  is attached to the crossbar  240  by inserting the midpoint shank  243  into the cavity  214   a  of the curved support  210 . In one embodiment, the crossbar is cylindrical and 6 inches in diameter. In one embodiment, the top  246  of the crossbar  240  is 10 feet from the playing field  10  when the goal post  1  is in the raised position. 
         [0022]    Each of the two uprights  260  includes a lower end  262 , a lower end cavity  263 , an upper end  264  and an inside  266 . The lower end cavity  263  is a cylindrical cavity larger in diameter than the end shank  245  of the crossbar  240 , and located at the lower end  262 . One upright  260  is mounted to each of the two ends  244  of the crossbar  240  by inserting the shank  245  into the cavity  263  and securing the upright  260  with set screws (not shown). The two uprights  260  are substantially parallel to each other, and each is substantially perpendicular to the crossbar  240 . In one embodiment, the inside  266  of each of the uprights  260  are spaced 18 feet and 6 inches from one another. In one embodiment, when the goal post  1  is in the raised position, the upper end  264  of the upright  260  is 40 feet above the playing field  10 , which is the distance required by the National Football League (“NFL”). In another embodiment, when the goal post  1  is in the raised position, the upper end  264  of the upright  260  is 30 feet above the playing field  10 , which is the minimum distance required by the National Collegiate Athletic Association (“NCAA”). In one embodiment, the diameter of each of the uprights  260  is 4 inches. 
         [0023]    With reference to  FIGS. 2B ,  3 A,  3 B and  4 , the pivot point assembly includes a base portion pivot assembly  302 , an upper portion pivot assembly  304 , a pivot pin assembly  306  and a locking assembly  308 . 
         [0024]    The base portion pivot assembly  302  includes a lower pivot bar  330 , two lower pivot gussets  340 , and two lower pivot knuckles  320  each having a bore  326 . 
         [0025]    The lower pivot bar  330  has two ends  332  and is a rectangular plate having a long axis slightly longer than the diameter of the lower support  110  and a short axis approximately the same width as the horizontal portion  112   b.  The lower pivot bar  330  is mounted on top of the horizontal portion  112   b  so that the two ends  332  of the lower pivot bar  330  extend beyond the sides of the lower support  110 . 
         [0026]    Each lower pivot gusset  340  is a plate in the shape of a right triangle having a short leg  342 , a long leg  344  and a hypotenuse  346 . One of the two lower pivot gussets  340  is mounted to the lower support  110  such that the long leg  344  is substantially parallel with the longitudinal axis of the lower support  110 , the short leg  342  of the lower pivot gusset  340  extends substantially perpendicular to the longitudinal axis of the lower support  110 , and the short leg  342  abuts one of the ends  332  of the lower pivot bar  330 . The other lower pivot gusset  340  is mounted in substantially the same way, except that the short leg  342  abuts the other of the ends  332  of the lower pivot bar  330 . The lower pivot gussets  340  serve to buttress the ends  332  of the lower pivot bar  330  that extend beyond the diameter of the lower support  110 . 
         [0027]    Each lower pivot knuckle  320  is a plate in the shape of an arched rectangle with a flat end  322  and an arched end  324 . Each lower pivot knuckle  320  has a lower pivot knuckle bore  326  near the arched end  324 . One lower pivot knuckle  320  is mounted on each of the ends  332  of the lower pivot bar  330  such that the two lower pivot knuckles  320  extend substantially parallel to the longitudinal direction of the lower support  110  and the two lower pivot knuckle bores  326  are coaxial. 
         [0028]    The upper portion pivot assembly  304  includes an upper clevis plate mount plate  216 , an upper clevis plate  272 , and a pivot tube  220 . 
         [0029]    The upper clevis plate mount plate  216  is a D-shaped plate and is mounted on the end of the beveled portion  212   a  such that the flat side of the D abuts and is parallel to the flat portion  212   b.    
         [0030]    An upper clevis plate  272  is a fin-shaped plate having a flat end  271  and a tapered end  273  at an angle to the flat end  271 . The flat end  271  is mounted to the upper clevis plate mount plate  216  such that the upper clevis plate  272  is substantially perpendicular to the upper clevis plate mount plate  216 . The upper clevis plate  272  includes an upper clevis plate lock pin bore  274 , an upper clevis plate rigging bore  275  and an upper clevis plate mount bore  276 . The upper clevis plate rigging bore  275  is provided as a convenience to a ground crew installing, removing or maintaining the goal post  1 . The upper clevis plate rigging bore  275  is approximately 1 inch in diameter, and is intended to be used in conjunction with an anchor shackle (not shown) as a rigging point, making it convenient to hoist the goal post  1  into and out of the ground. 
         [0031]    The pivot tube  220  defines a pivot tube bore (not shown). As shown in  FIG. 4 , the pivot tube  220  is welded to the flat portion  212   b  of the curved support  210 . 
         [0032]    The pivot pin assembly  306  includes a pivot pin  310  and optionally a pivot pin lock ring  312 . The pivot pin  310  is a cylinder having a diameter small enough to fit within the lower pivot knuckle bores  326  and a length at least as long as the distance between the lower pivot knuckles  320 . To accommodate the pivot pin lock ring  312 , the pivot pin  310  also includes at least one groove (not shown). In one embodiment, pivot pin  310  includes two grooves, one on either side of the pivot pin  310 . The grooves are positioned on the pivot pin  310  such that the grooves are spaced apart wider than the outside edges of the lower pivot knuckles  320 . 
         [0033]    The pivot pin lock ring  312  is a circular ring having an open section that is dimensioned to fit into one groove. When the lock ring  312  is positioned into the groove, the outside diameter of the pivot pin lock ring  312  is larger than the lower pivot knuckle bores  326 . One pivot pin lock ring  312  is used for each groove. 
         [0034]    With reference to  FIGS. 2B ,  3 A and  3 B, the locking assembly  308  includes a lower support cap plate  114 , a lock pin clevis  360  having a bore  362 , the lock pin bore  274  on the upper clevis plate  272 , and a lock pin  350 . 
         [0035]    The lower support cap plate  114  is a D-shaped plate mounted on top of the beveled portion  112   a  of the lower support  110  such that the flat portion of the lower support cap plate  114  is close to and parallel to the pivot axis. 
         [0036]    The lock pin clevis  360  includes two substantially parallel planar plates  360   a  and  360   b . Each of the planar plates  360   a  and  360   b  have an arched rectangular shape having an arched short edge  364  and a contoured long edge  365  that fits the contours of the top portion  112  where the lower support cap plate  114  adjoins the lower support  110 . The plates  360   a  and  360   b  are spaced apart to allow the upper clevis plate  272  to fit between them. In an alternative embodiment, the arched edge  364  of each of the plates  360   a  and  360   b  are spaced farther apart from one another than the contoured long edge  365  of each of the plates  360   a  and  360   b  for better guiding of the upper clevis plate  272  between the plates  360   a  and  360   b . Each of the plates  360   a  and  360   b  have a lock pin clevis bore  362  near the arched short edge  364 . The lock pin clevis  360  is mounted on top of the lower support  110  at an acute angle to the longitudinal axis of the lower support  110  and resting in part on the lower support cap plate  114 . 
         [0037]    The lock pin bore  274  on the upper clevis plate  272  is oval in shape with the smaller axis of the oval being approximately the same diameter as each of the lock pin clevis bores  362 . 
         [0038]    The lock pin  350  is T-shaped and includes a cylindrical shaft  352  and a cylindrical head  354  mounted perpendicular to the shaft  350  to form a T shape. The cylindrical shaft  350  is sized to fit within the lock pin bore  274  and the lock pin clevis bores  362 . The lock pin  350  further includes a pushbutton  356  on the head  354  and a ball  358  on the shaft  352 . The ball  358  prevents the shaft  352  from moving through the lock pin bore  274  and the lock pin clevis bores  362 . When the pushbutton  356  is pushed, the ball  358  retracts into the shaft  352  so the lock pin  350  can be inserted through the lock pin bore  274  and the lock pin clevis bores  362 . 
         [0039]    As shown in  FIG. 2B , the hydraulic assembly  400  includes a cylinder assembly  402 , a lower mount assembly  404 , an upper mount assembly  406  and a hydraulic control assembly  408 . 
         [0040]    With reference to  FIGS. 3A ,  3 B and  5 , the cylinder assembly  402  includes a hydraulic cylinder  410 , a piston  420  and a piston rod  421 . The piston  420  is within the hydraulic cylinder  410  and is connected to the piston rod  421 , which can extend from and retract into the hydraulic cylinder  410  while the piston  420  traverses the length of the hydraulic cylinder  410 . The piston rod  421  is substantially parallel to and coaxial with the hydraulic cylinder  410 . The piston  420  divides the hydraulic cylinder  410  into an upper chamber  410   a  containing the piston rod  421 , and a lower chamber  410   b . The upper chamber  410   a  is filled with a hydraulic fluid (not shown), for example oil or any other suitable incompressible fluid. In one embodiment, the hydraulic fluid is Tellus®  46  oil from Shell (Houston, Tex.). The lower chamber  410   b  is filled with air and is connected by an air line  435  to a hydraulic fluid reservoir  450  above the fluid level to limit the amount of moisture or other contaminants from entering the lower chamber  410   b  of the hydraulic cylinder  410 . In the case that hydraulic fluid or other liquids enter the lower chamber  410   b , the connection to the reservoir  450  permits the moisture or liquid to flow to the reservoir  450  via the air line  435 . As the piston rod  421  extends from the hydraulic cylinder  410 , the piston  420  moves up such that the volume of the upper chamber  410   a  decreases and the volume of the lower chamber  410   b  increases. 
         [0041]    With reference to  FIGS. 3B and 4 , the lower mount assembly  404  includes a lower clevis plate mount plate  116 , a lower clevis plate  172  having a lower clevis plate mount bore  176 , a cylinder clevis  412  having cylinder clevis mount bores  416   a  and  416   b , and a lower mount clevis pin  178 . 
         [0042]    The lower clevis plate mount plate  116  is a curved plate that is mounted flush against the sidewall of the lower support  110 . The lower clevis plate mount plate  116  is a doubler plate to strengthen the joint between the lower clevis plate  172  and the lower support  110 . 
         [0043]    The lower clevis plate  172  is a triangular plate having a short leg  173 , a long leg  174  and a hypotenuse  175 . The lower clevis plate  172  is mounted perpendicular to the lower clevis plate mount plate  116  along the long leg  174  such that the lower clevis plate  172  is substantially parallel to the longitudinal axis of the lower support  110  and the short leg  173  faces the top portion  112  of the lower support  110 . The lower clevis plate  172  includes the lower clevis plate mount bore  176  near the short leg  173 . 
         [0044]    The hydraulic cylinder  410  has on an end opposite the piston rod  421  the cylinder clevis  412  that is substantially parallel to the longitudinal axis of the hydraulic cylinder  410 . The cylinder clevis  412  is an integral part of the hydraulic cylinder  410  as supplied by the manufacturer. The cylinder clevis  412  includes two substantially parallel triangular plates  412   a  and  412   b  that are spaced to allow the lower clevis plate  172  to fit between them. Each of the parallel plates  412   a  and  412   b  include a cylinder clevis mount bore  416   a  and  416   b , respectively. The cylinder clevis mount bores  416   a  and  416   b  are substantially the same diameter as the lower clevis plate mount bore  176 . 
         [0045]    The lower mount clevis pin  178  is cylindrical and includes a cylindrical shaft  178   a  and a head  178   b  mounted on one end of the shaft  178   a . On an end opposite the head  178   b , the shaft  178   a  has a bore  178   c . The bore  178   c  is substantially perpendicular to the longitudinal axis of the shaft  178   a . A lower mount cotter pin  179  is a length of wire bent into shape resembling a capital letter “R”. The straight leg of the cotter pin  179  fits in the bore  178   c . The bent leg of the lower mount cotter pin  179  grips the side of the shaft  178   a . The cylindrical shaft  178   a  is sized to fit within the lower clevis plate mount bore  176  and the cylinder clevis mount bores  416   a  and  416   b . The cotter pin  179  and the head  178   b  are sized such that the lower mount clevis pin  178  cannot be removed from the lower clevis plate mount bore  176  and the cylinder clevis mount bores  416   a  and  416   b  when the cotter pin  179  is placed in the bore  178   c.    
         [0046]    The upper mount assembly  406  includes the upper clevis plate mount bore  276  on the upper clevis plate  272 , a piston clevis  422  having piston rod mount bores  426   a  and  426   b , and an upper mount clevis pin  278 . 
         [0047]    The piston clevis  422  is attached to an end of the piston rod  421  opposite the hydraulic cylinder  410 . The piston clevis  422  is a single, forged piece that threads onto the piston rod  421 , and is typically provided by the manufacturer. The piston clevis  422  is substantially parallel to the longitudinal axis of the piston rod  421 . The piston clevis  422  includes two substantially parallel plates  422   a  and  422   b  that are shaped like arched rectangles, each having a flat end  423  and an arched end  424 . The parallel plates  422   a  and  422   b  are spaced to allow the upper clevis plate  272  to fit between them. The parallel plates  422   a  and  422   b  are mounted to the piston rod  421  at the flat end  423 . Each of the parallel plates  422   a  and  422   b  include a piston clevis mount bore  426   a  and  426   b , respectively, near the arched end  424 . 
         [0048]    The upper mount clevis pin  278  is cylindrical and includes a cylindrical shaft  278   a  and a head  278   b  mounted on one end of the shaft  278   a . On an end opposite the head  278   b , the shaft  278   a  has a bore  278   c . The bore  278   c  is substantially perpendicular to the longitudinal axis of the shaft  278   a . An upper mount cotter pin  279  is a length of wire bent into shape resembling a capital letter “R”. The straight leg of the cotter pin  279  fits in the bore  278   c . The bent leg of the lower mount cotter pin  279  grips the side of the shaft  278   a . The cylindrical shaft  278   a  is sized to fit within the upper clevis plate mount bore  276  and the piston clevis mount bores  426   a  and  426   b . The cotter pin  279  and the head  278   b  are sized such that the upper mount clevis pin  278  cannot be removed from the upper clevis plate mount bore  276  and the piston clevis mount bores  426   a  and  426   b  when the cotter pin  279  is placed in the bore  278   c.    
         [0049]    With reference to  FIG. 5 , the hydraulic control assembly  408  includes a hydraulic line  430 , the air line  435 , and actuator valve  442 , an adjustable valve  444 , a safety valve  446 , the hydraulic fluid reservoir  450 , a ball check valve  462  and a gear pump  464 . 
         [0050]    The hydraulic line  430  is tubing and/or piping that connects the upper chamber  410   a  to the reservoir  450 . Other components of the hydraulic control assembly  408  including the actuator valve  442 , adjustable valve  444 , safety valve  446 , one way valve  462  and gear pump  464  are connected between the upper chamber  410   a  and the reservoir  450  by the hydraulic line  430 . 
         [0051]    The air line  435  is tubing and/or piping that connects the lower chamber  410   b  directly to the airspace above the fluid in the reservoir  450 . 
         [0052]    The adjustable valve  444  is connected between the upper chamber  410   a  and three components connected in parallel between the adjustable valve  444  and the reservoir  450 . The three components include the actuator valve  442  for lowering the upper portion assembly  200 , the gear pump  464  for raising the upper portion assembly  200 , and a safety valve  446 . 
         [0053]    The adjustable valve  444  includes an adjustable orifice  444   a  and a ball check valve  444   b . The adjustable orifice  444   a  is an opening that is adjustable in size, which effectively meters the rate at which the hydraulic fluid can flow from the upper chamber  410   a  through the adjustable valve  444 . The ball check valve  444   b  allows fluid to flow freely into the upper chamber  410   a  from the gear pump  464 . 
         [0054]    The actuator valve  442  is a spring-loaded valve that, when actuated, allows fluid to flow from the upper chamber  410   a  to the reservoir  450 . When the actuator  442  is released, the spring-loaded valve automatically shuts and all fluid flow ceases. The piston  420  does not and cannot extend and thus lower the upper portion assembly  200  when the actuator  442  is not actuated. Additionally, holding the actuator valve  442  in the open position will prevent the gear pump from raising the upper portion assembly  200 . 
         [0055]    The safety valve  446  is an integral part of the actuator valve  442 . In the event that hydraulic pressure in the upper chamber  410   a  exceeds a pre-determined pressure, hydraulic fluid will flow from the upper chamber  410   a  through the adjustable valve  444  and the safety valve into the reservoir  450 . This is a safety feature, designed to prevent damage to the goal post  1 , including the hydraulic assembly  400 . 
         [0056]    Between the gear pump  464  and the adjustable valve  444  is a one way valve  462 , which allows hydraulic fluid to flow from the gear pump  464  to the upper chamber  410   a , but not from the upper chamber  410   a  to the gear pump  464 . In one embodiment, the one way valve  462  is a ball check valve. The gear pump  464  acts to move fluid from the reservoir  450  through the one way valve  462  to the upper chamber  410   a , and therefore retract the piston rod  421  into the hydraulic cylinder  410 . In one embodiment, the pump  464  is a gear pump that is operated by a battery powered hand held drill or a manual crank handle. 
         [0057]    The hydraulic fluid reservoir  450  stores the hydraulic fluid flowing from the upper chamber  410   a  and air flowing from the lower chamber  410   b . The reservoir  450  is open to the atmosphere via a vented fluid fill cap (not shown) located at the top of the reservoir  450 . This design limits the amount of moisture or other contaminants entering the hydraulic assembly  400 . 
         [0058]    An enclosure (not shown) made of sheet metal may be formed around the hydraulic assembly  400  to facilitate removal and handling of the hydraulic assembly and also for aesthetic and safety purposes. 
         [0059]    The assembly of the goal post  1  will now be described with reference to  FIGS. 2A ,  2 B,  3 A,  3 B,  4  and  5 . 
         [0060]    To connect the upper portion assembly  200  to the base portion assembly  100 , the pivot tube  220  is positioned between the two lower pivot knuckles  320 , with the pivot tube bore aligned with the two lower pivot knuckle bores  326 . The pivot pin  310  is inserted through the two lower pivot knuckle bores  326  and the pivot tube bore, such that the two grooves  311  remain exposed. One of the two locking rings  312  is positioned into each of the two grooves  311  to lock the pivot pin  310  in place. 
         [0061]    To mount the piston rod  421  to the curved support  210 , the upper clevis plate  272  is inserted into the piston clevis  422 , and the upper clevis plate mount bore  276  is aligned with the piston clevis mount bores  426   a  and  426   b . The shaft  278   a  of an upper mount clevis pin  278  is inserted through all three mount bores  276 ,  426   a  and  426   b . The cotter pin  279  is then inserted through the bore  278   c  of the upper mount clevis pin  278 . 
         [0062]    To mount the hydraulic cylinder  410  to the lower support  110 , the lower clevis plate  172  is inserted into the cylinder clevis  412 , and the lower clevis plate mount bore  176  is aligned with the cylinder clevis mount bores  416   a  and  416   b . The shaft  178   a  of the lower mount clevis pin  178  is inserted through all three mount bores  176 ,  416   a  and  416   b . The cotter pin  179  is then inserted through the bore  178   c  of the lower mount clevis pin  178 . 
         [0063]    Because the hydraulic fluid is incompressible, the upper chamber  410   a  must allow hydraulic fluid to escape in order for the upper chamber  410   a  to decrease in volume. Likewise, the lower chamber  410   b  must allow air to enter in order for the lower chamber  410   b  to increase in volume. This is accomplished by connecting the upper chamber  410   a  to the reservoir  450  by the hydraulic line  430  via the adjustable valve  444 , the actuator valve  442  and the safety valve  446 ; and the lower chamber  410   b  to the reservoir  450  by the air line  435 . 
         [0064]    When the goal post  1  is in the raised position, as shown in  FIGS. 1 ,  2 A,  3 A and  4 , the first end  212  of the curved support  210  is substantially perpendicular to the playing field  10 , and the second end  214  is substantially parallel to the playing field  10 . When the goal post  1  is in the lowered position, the first end  212  is substantially parallel to the playing field  10 , and the second end  214  is substantially perpendicular to the playing field  10 . In one embodiment, when the goal post  1  is in the lowered position, as shown in  FIGS. 2B and 3B , each of the uprights  260  and the crossbar contact the playing field  10 . 
         [0065]    When the goal post  1  is in the raised position, the upper clevis plate lock pin bore  274  aligns with each of the lock pin clevis bores  362 . The T-shaped lock pin  350  is inserted through all three bores to maintain the goal post  1  in the raised position. 
         [0066]    To collapse the goal post  1  from the raised position to the lowered position, the pump  464  is actuated to drive hydraulic fluid from the reservoir  450  through the pump  464 , the ball check valve  462  and the ball check valve  444   b  to the upper chamber  410   a . This moves the piston  420  down to increase the volume of the upper chamber  410   a , which in turn retracts the piston rod  421  farther into the hydraulic cylinder  410 . This retraction pulls the upper portion assembly  200  farther into a raised position, which unloads the lock pin  350  for easier removal from the lock pin clevis bores  362  and the upper clevis plate lock pin bore  274 . The oval shape of the lock pin bore  274  allows the lock pin  350  to be more easily removed. After the lock pin  350  is removed, the force of gravity acts to pivot the upper portion assembly  200  toward the playing field  10  until the uprights  260  rest on the playing field  10 . 
         [0067]    However, when the hydraulic assembly  400  is mounted to the goal post  1 , the curved support  210  is attached to the piston rod  421  and the lower support  110  is attached to the hydraulic cylinder  410 . The upper portion assembly  200  therefore does not and cannot pivot about the pivot point assembly  300  unless the actuator  442  is actuated to allow the hydraulic fluid to move from the upper chamber  410   a  through the orifice  444   a  and the actuator  442  to the reservoir, thereby allowing the piston  420  to move and the piston rod  421  to extend out of the hydraulic cylinder  410 . The adjustable valve  444  can be adjusted to control the rate at which the upper portion assembly  200  lowers. 
         [0068]    Because the actuator  442  does not allow the upper portion assembly  200  to pivot unless the actuator  442  is actuated, this is referred to as a “dead man” operation. If an operator lets go of the actuator  442 , the spring-loaded valve will close and all motion of the goal post  1  will cease. 
         [0069]    To raise the goal post  1  from the lowered position to the raised position, resistance from the hydraulic cylinder  410  and piston  420  should be minimized. This can be accomplished by removing the hydraulic assembly  400  and raising the upper portion assembly  200  manually. The upper portion assembly  200  can then be raised manually by grasping any part of the upper portion assembly  200  and hoisting the goal post  1  into the raised position. Alternatively, the upper portion assembly  200  can be raised by any other method. 
         [0070]    In another embodiment, the pump  464  can provide a hydraulic assist to raise the upper portion assembly  200 . The pump  464  is actuated to drive hydraulic fluid from the reservoir  450  through the pump  464 , the ball check valve  462  and the ball check valve  444   b  to the upper chamber  410   a . This moves the piston  420  down to increase the volume of the upper chamber  410   a , which in turn retracts the piston rod  421  farther into the hydraulic cylinder  410 . This retraction pulls the upper portion assembly  200  farther into a raised position 
         [0071]    To remove the hydraulic assembly  400 , the upper mount clevis pin  278  and the lower mount clevis pin  178  are removed. The upper mount cotter pin  279  is removed from the bore  278   c . Then, the upper mount clevis pin  278  is removed from the piston clevis mount bores  424   a  and  424   b  and the upper clevis plate mount bore  274 , which allows the upper clevis plate  272  to be removed from the piston clevis  422 , and therefore uncouple the piston rod  421  from the curved support  210 . The lower mount cotter pin  179  is removed from the bore  178   c . Then, the lower mount clevis pin  178  is removed from the cylinder clevis mount bores  416   a  and  416   b  and the lower clevis plate mount bore  176 , which allows the lower clevis plate  172  to be removed from the cylinder clevis  412 , and therefore uncouple the hydraulic cylinder  410  from the lower support  110 . Once the upper portion assembly is raised, manually or otherwise, the upper clevis plate  272  is inserted between the parallel plates  360   a  and  360   b  of the lock pin clevis  360 . The upper clevis plate lock pin bore  274  is aligned with the lock pin clevis bores  362 , and the shaft  352  of the lock pin  350  is inserted through all three lock pin bores. 
         [0072]    The hydraulic assembly  400  can be removed when the upper portion assembly  200  is in either the raised or lowered positions. The hydraulic assembly  400  would typically be removed when the upper portion assembly  200  is in the raised position. However, the hydraulic assembly  400  would be removed when the upper portion assembly  200  is in the lowered position to facilitate removal of the goal post  1  from the playing field  10 , as frequently occurs when the stadium is used for other sporting events such as soccer, or for other events such as concerts. 
         [0073]    While a particular form of the invention has been illustrated and described, it will be apparent that various modifications can be made without departing from the spirit and scope of the invention. For example, different mounting and locking mechanisms may be employed, the hydraulic line  430  may have a different configuration or different components, or the dimensions of the goal post may be changed. Accordingly, it is not intended that the invention may be limited except by the appended claims.