Abstract:
A self-locking, high-pressure stopper is disclosed. Also disclosed is a method of using the stopper. The stopper allows a branch pipe to be plugged from above ground using an elongated insertion tool. The self-locking stopper of the present invention includes a body having O-ring seals that is inserted into the branch pipe that is to be plugged. The self-locking stopper has outwardly biased locking tabs that are provided to engage a shoulder or step in the branching pipe in order to prevent the stopper from being pulled out, or pushed out by fluid pressure, once it is in place. The stopper system also includes a flanged insertion pipe used for inserting the stopper into the branch pipe. The stopper also has an adapter for engagement by an insertion tool that allows a user to insert the stopper from above ground.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     This invention relates generally to a stopper for closing off an unused branching pipe in a main fluid supply line. 
     2. Brief Description of the Related Art 
     In many applications the need arises to close or seal off an unused branching pipe or T-connection in a main fluid supply line. For example, when a building is to be demolished or a site modified in such a way that gas supply to the site is no longer required, the T-connection that branches off from the main gas line to supply the site has to be sealed off. Heretofore, an access well had to be dug to the branching pipe or the T-connection. The access well had to be large enough for a man to descend into to access and seal off branching pipe or the T-connection. This process is very time consuming and expensive, requiring a considerable amount of excavation. The need persists in the art for a device that allows branching pipes, T-connections and the like to be closed off through a relatively small hole drilled into the ground to reach the buried branching pipe, T-connection or the like. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a self locking stopper and method of its use that allows the stopper to be inserted into a branching pipe through a relatively small bore hole. The self-locking stopper of the present invention includes a body having O-ring seals that is inserted into the branch pipe that is to be plugged. The self-locking stopper has outwardly biased locking tabs that are provided to engage a shoulder or step in the branching pipe in order to prevent the stopper from being pulled out, or pushed out by fluid pressure, once it is in place. The stopper system also includes a flanged insertion pipe used for inserting the stopper into the branch pipe. The stopper also has an adapter for engagement by an insertion tool that allows a user to insert the stopper from above ground. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an environmental view showing the self-locking, high-pressure stopper according to the present invention installed in a T-connection. 
     FIG. 2 is a right side view in elevation of the plug body of the self-locking, high-pressure stopper according to the present invention. 
     FIG. 3 is a front view in elevation of the plug body of the self-locking, high-pressure stopper according to the present invention. 
     FIG. 4 is a right side view in elevation of the locking tab of the self-locking, high-pressure stopper according to the present invention. 
     FIG. 5 is a bottom view of the locking tab of the self-locking, high-pressure stopper according to the present invention. 
     FIG. 6 is an isometric view of the locking tab of the self-locking, high-pressure stopper according to the present invention. 
     FIG. 7 is a fragmentary, cross sectional view showing the locking tabs and the plug body, of the self-locking, high-pressure stopper according to the present invention, installed in a pipe “TEE”. 
     FIG. 8 is a cross sectional view of the insertion tube of the self-locking, high-pressure stopper according to the present invention. 
     FIG. 9 is an isometric view of the insertion tube of the self-locking, high-pressure stopper according to the present invention. 
     FIG. 10 is a cross sectional view of the insertion tool for use with the self-locking, high-pressure stopper according to the present invention. 
    
    
     Like reference numerals indicate like elements throughout the several views. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIGS. 1-9, an illustrative example of a self-locking, high-pressure stopper and stopper system according to the present invention can be seen. The self-locking, high-pressure stopper system  100  of FIGS. 1-9 includes an insertion tube  102  and a self-locking, high-pressure stopper  104 . In the illustrated example of FIG. 1 the stopper system  100  is shown plugging off a pipe “TEE”  106  that is branching off from a gas pipe or main  108 . 
     The insertion tube  102  comprises a tubular portion  110  having an annular flange  112  at a first end thereof. The stopper  104  comprises a stopper body  114  having a middle portion  116 , a first end portion  118 , and a second end portion  120 . The middle portion  116  is positioned intermediate the first end portion  118  and the second end portion  120 . The middle portion  116  can be substantially cylindrical as best illustrated in FIGS. 2 and 3. The first end portion  118  is provided with an insertion tool engagement portion  122 . Also, the first end portion  118  is provided with a large diameter portion  124  and a tapering diameter portion  126  in tandem, with the large diameter portion  124  being positioned intermediate the tool engagement portion  122  and the tapering diameter portion  126 . The large diameter portion  124  has a snap-ring groove  128 . The tapering diameter portion  126  has a diameter that uniformly tapers or decreases from a large diameter at one end to a small diameter at the other end in the direction of the longitudinal axis l of the stopper body  114 . The small diameter end of the tapering diameter portion  126  is positioned adjacent the large diameter portion  124 , while the large diameter end of the tapering diameter portion  126  is positioned adjacent the middle portion  116 . The diameter of the small diameter end of the tapering diameter portion  126  is smaller that the diameter of the large diameter portion  124 . 
     The second end portion  120  is provided with a locking tab housing portion  130 , a pair of tapering diameter portions  132  and  134 , and a large diameter portion  136 . The tapering diameter portions  132  and  134  each have a diameter that uniformly tapers or decreases from a large diameter at one end to a small diameter at the other end in the direction of the longitudinal axis l of the stopper body  114 . The small diameter end of the tapering diameter portion  134  is positioned adjacent the middle portion  116 . The large diameter portion  136  is positioned intermediate the tapering diameter portion  132  and the tapering diameter portion  134 . The large diameter end of the tapering diameter portion  134  is positioned adjacent the large diameter portion  136 . The small diameter end of the tapering diameter portion  132  is positioned adjacent the large diameter portion  136 , and the large diameter end of the tapering diameter portion  132  is positioned adjacent the locking tab housing portion  130 . The small diameter end of the tapering diameter portion  134  is smaller in diameter than the middle portion  116 . The small diameter end of the tapering diameter portion  132  is smaller in diameter than the large diameter portion  136 . 
     The insertion tool engagement portion  122  is in the form of a rod having a narrowing waist portion  138  located intermediate two large diameter portions  140  and  142 . Each of the two large diameter portions  140  and  142  is of substantially uniform diameter throughout its length. In the illustrated embodiment, the two large diameter portions  140  and  142  are substantially of the same diameter. In the illustrated embodiment, the waist portion  138  has a minimum diameter at about its center. The diameter of the waist portion  138  increases from its minimum value with decreasing distance from either one of the two large diameter portions  140  and  142 . 
     In the illustrated embodiment, the large diameter portion  136 , the middle portion  116 , the locking tab housing portion  130 , and the large diameter portion  124  are of substantially the same diameter. The locking tab housing portion  130  has a passage  144  that extends through the locking tab housing portion  130  in a direction substantially transverse or perpendicular to the longitudinal axis of the stopper body  114 . The passage  144  houses at least a portion of each of the two locking tabs  146 . The passage  144  has a cross section that resembles the union of a rectangle with a circle, with the center of the circle positioned at the intersection of the diagonals of the rectangle and with the length of the rectangle being larger than the diameter of the circle. 
     The two locking tabs  146  are each in the form of a body  148  having a beveled projection  150  on one side and a cuboid projection  152  on the other side. The tab body  148  is approximately in the shape of a rectangular parallelepiped having its shorter edges beveled. The tab body  148  is dimensioned to bear against the portions of the passage  144  that follow a rectangular contour when viewed in cross section and to slidably support the locking tab  146  within the passage  144 . In addition, each end of the spring  154  bears against a respective one of the tab bodies  148  and the cuboid projection  152  of each of the locking tabs  146  extends through at least one of the coils of the spring  154  when the stopper  104  is fully assembled. The beveled projection  150  has a chisel-like profile created by a beveled surface  156  and a substantially flat surface  158 . The distal edge  160  of the beveled projection  150  and the beveled surface  156  may be arcuate so as to follow the inner surface of the pipe “TEE”  106 . 
     The tubular portion  110  of the insertion tube  102  is open at both ends. The insertion tube  102  has a chamfered surface  162  extending between the inner surface of the tubular portion  110  and the surface  164  of the annular flange  112  that surrounds the opening at the first end of the tubular portion  110 . The chamfered surface  162  forms a funnel that eases the insertion of the end of the stopper  104 , having the outwardly biased locking tabs  146  installed therein, into the insertion tube  102 . 
     The locking tabs  146  are outwardly biased relative to the passage  144  by some type of biasing means. In the illustrated example, the locking tabs  146  are outwardly biased by a coil spring  154  positioned within the passage  144 . 
     In the illustrated example of FIG. 1, the main tubular portion  166  of the pipe “TEE”  106  has an annular recess or shoulder  168 . A branching portion  170  branches off the main tubular portion  166 . The locking tabs  146  engage the annular shoulder  168  to keep the stopper system  100  from being pulled or pushed out of the pipe “TEE”  106 . 
     The stopper  104  further includes o-rings  200 ,  202 , and  204  and a snap ring  206 . The o-rings  200 ,  202 , and  204  are placed around the tapering diameter portions  126 ,  132 , and  134 , respectively. The snap ring  206  is received in part in the groove  128 . 
     Referring to FIG. 10, the insertion tool  172  for inserting the stopper system  100  can be seen. The insertion tool  172  includes an elongated tube  174  having a socket  176  fixed to on end thereof. The cavity  178  of the socket  176  is sized to receive at least a portion of the insertion tool engagement portion  122  that includes the waist portion  138 . The socket  176  has passages  180  that house at least a part of the balls  182 . The passages  180  open to the interior of the cavity  178  to allow a portion of the balls  182  to project into the bore of the cavity  178 . The passages  180  are also open to the exterior of the socket  176 . The diameter of the openings of the passages  180  to the bore of the cavity  178  is less than the diameter of the balls  182 . A sleeve assembly  184  surrounds one end of the tube  174  and the socket  176 . The sleeve assembly  184  has an annular cavity  186 . An elongated threaded rod  188  is movably housed within the tube  174 . One end of the rod  188  is engaged to a push button  190 . The other end of the rod  188  is engaged to a plug  192 . The plug  192  has a pair of rods  194  projecting laterally from either side thereof. The rods  194  pass through elongated slots  196  and engage the sleeve assembly  184  such that the sleeve assembly  184  moves in response to movement of the button  190 . A spring  198  is provided intermediate the plug  192  and the socket  176 . The spring  198  biases the plug  192 , the rods  194 , the rod  188 , the button  190 , and the sleeve assembly  184  toward the engaged position shown in FIG.  10 . 
     With the insertion tool engagement portion  122  positioned in the socket  176  such that the waist portion  138  registers with the passages  180  and with the sleeve assembly  184  in the engaged position, the balls  182  engage the waist portion  138  such that the stopper  104  is securely held by the insertion tool  172 . With the sleeve assembly  184  in the engaged position, portions of the sleeve assembly block off the opening of the passages  180  to the exterior of the socket  176  such that the balls  182  remain in a position where a portion of the balls  182  projects into the bore of the cavity  178  and remains in engagement with the waist portion  138  of the insertion tool engagement portion  122 . To release the stopper  104 , the button  190  is pushed inward relative to the tube  174 . As the button  190  is pushed inward, the sleeve assembly  184  moves relative to the socket  176  such that the cavity  186  is at least partly brought into registry with the passages  180 . The balls  182  can then move out of the bore of the cavity  178  to thereby allow the stopper  104  to be released. 
     In use, the locking tabs  146  are placed in the passage  144  with the spring  154  between them. The locking tabs  146  are then simultaneously pressed into the passage  144  to minimize the projection of the locking tabs  146  from the stopper body  114 . The end portion  120  is then inserted into the insertion tube  102  through the end having the flange  112 . In this configuration the insertion tube  102  prevents the locking tabs  146  from falling out of the passage  144  and the o-rings  202  and  204  frictionally hold the insertion tube  102  in place relative to the stopper body  114 . The stopper system  100  is then secured to the end of the insertion tool  172  as previously explained above. Using the insertion tool  172  the stopper system  100  is lowered to the pipe “TEE”  106  and inserted into the main pipe portion  166  of the pipe “TEE”  106 . The flange  112  limits the movement of the insertion tube  102  relative to the pipe “TEE”  106 . Further insertion of the stopper  104  into the main pipe portion  166  of the pipe “TEE”  106  causes the stopper  104  to move relative to the insertion tube  102  until the snap ring  206  abuts the flange  112 . At this time the snap ring  206  limits the further insertion of the stopper  104  into the main pipe portion  166  of the pipe “TEE”  106 . In the mean time, the locking tabs  146  extend outward into the larger diameter lower end portion  208  of the main pipe portion  166  of the pipe “TEE”  106  to engage the shoulder  168  and secure the stopper  104  within the main pipe portion  166  of the pipe “TEE”  106 . The insertion tool  172  is then disengaged from the stopper  104  by pressing in the button  190  and lifting the insertion tool  172  away from the stopper  104 . The pipe “TEE”  106  is now plugged off. 
     With the snap ring  206  abutting the flange  112  as shown in FIG. 1, the o-rings  202  and  204  clear the insertion tube  102  and seal any gaps between the stopper body  114  and the interior surface of the main pipe portion  166  of the pipe “TEE”  106 . The o-ring  200  centers and laterally supports the stopper body  114  within the insertion tube  102 . The tapered configuration of the portions  126 ,  132 , and  134  cause the o-rings  200 ,  204 , and  202  to be even more strongly wedged between the stopper body  114  and the interior surface of the main pipe portion  166  of the pipe “TEE”  106 , if any attempt is made to pull out the stopper  104 . 
     With the stopper system  100  in place, the pipe “TEE”  106  is then sawed completely through just below the branching pipe  170 . External threads are then cut on the exterior of the remaining portion of the main pipe portion  166  of the pipe “TEE”  106 . A threaded cap is then applied to the remaining portion of the main pipe portion  166  of the pipe “TEE”  106 , with the portion  120  of the stopper body, the o-rings  202  and  204 , the spring  154 , and the locking tabs  146  remaining in place, to complete the capping of the pipe “TEE”  106 . 
     It is to be understood that the present invention is not limited to the embodiments described above, but includes any and all embodiments within the scope of the appended claims. Furthermore, it is to be understood that the embodiments of the present invention disclosed above are susceptible to various modifications, changes and adaptations by those skilled in the art, without departing from the spirit and scope of the invention.