Plastic pipe thrust resistant joint

Claim 2

A plastic pipe arrangement comprising: a. a first plastic pipe having an end portion and a helical groove integrally formed in the internal surface of said end portion; b. a second cooperating plastic pipe having an end portion with an outer diameter slightly less than the inner diameter of said end portion of said first plastic pipe, said end portion of said second plastic pipe including a helical rib integrally formed on and protruding outwardly from its external surface and having a width which is substantially less than the width of said helical groove, said helical rib being adapted to cooperate with said helical groove of said first plastic pipe for connecting said plastic pipes together in a threaded fashion; and c. said groove and said rib including cooperating means for locking said plastic pipes together once the latter are threaded together said locking means including a locking slot formed in the inside surface of said first plastic pipe and extending from the rearward most end of said helical groove towards the forward most end thereof, a cooperating raised hook portion located at the forward most end of said helical rib and extending from the forward most end of said rib away therefrom, said raised portion and slot cooperating with one another after said pipes have been threaded together so as to interlock the pipes to one anotheR and means for forcing said hook portion into said locking slot after said pipes have been threaded together, said forcing means including a gasket disposed within a groove formed around said second plastic pipe and an annular shoulder formed in the internal surface of said first plastic pipe, said gasket compressing against said shoulder when said pipes are threaded together so that said compressed gasket forces said hook portion into said slot portion.

Claim 3

A plastic pipe arrangement according to claim 1 wherein said helical groove includes a forward most side wall extending into said first plastic pipe at an angle between approximately 30* and approximately 90* with respect to the internal surface of said first plastic pipe, at least a portion of said side wall providing a reliable shear resistant surface against which said helical rib is adapted to abut in response to longitudinal force tending to pull said pipes away from one another, once the latter are threaded together.

Claim 4

A plastic pipe arrangement according to claim 2 wherein said helical rib includes a rearward most shoulder extending outwardly from the external surface of said second plastic pipe at an angle between approximately 30* and approximately 90* with respect to the external surface of said second plastic pipe, at least a portion of said shoulder being adapted to abut against the side wall of said groove in response to said longitudinal forces.

Claim 5

A plastic pipe arrangement according to claim 1 wherein: a. the end portion of said first plastic pipe includes a plurality of helical grooves similar to said first-mentioned groove; b. the end portion of said second plastic pipe includes an equal plurality of helical ribs similar to said first-mentioned helical rib and adapted to cooperate with said helical grooves, respectively, for connecting said plastic pipes together in a threaded fashion; and c. each cooperating groove and rib includes said locking means.

Claim 6

A plastic pipe arrangement according to claim 4 wherein the end portions of said pipe sections include four pairs of said cooperating grooves and ribs, said pairs being equally circumferentially spaced apart around said end portions.

Claim 7

A bell and spigot joint for connecting two pipes together, said joint comprising: a. a bell end having at least one helical groove formed in its internal surface and directed inwardly from its free end and an inwardly protruding annular shoulder spaced longitudinally inwardly from said groove, said groove including a forward most side wall extending into said bell end at an angle between approximately 30* and approximately 90* with respect to the internal surface of said bell end; b. a spigot having at least one outwardly protruding helical rib formed on its external surface, directed inwardly from its free end and adapted to cooperate with said helical groove of said bell end for connecting the bell end and spigot together in a threaded fashion, said rib including a rearward most shoulder extending outwardly from the external surface of said spigot at an angle between approximately 30* and approximately 90* with respect to the external surface of said spigot, said shoulder being adapted to abut against said side wall of said helical groove in response to longitudinal forces tending to pull said bell end and spigot away from one another once the latter are threaded together; and c. means for locking said bell end and spigot together once the latter are joined together in said threaded fashion, said locking means including a locking slot formed in the internal surface of said bell end and extending from the rearward most end of said helical groove towards the outermost end thereof, a cooperating raised hook portion located adjacent the forward most end of said helical rib and adapted to engage within said locking groove after said bell end and spigot have been connecteD together in said threaded fashion and means for forcing said raised portion into said locking groove after said bell end and spigot have been threaded together, said forcing means including a resilient annular gasket positioned within a circumferential groove formed around the external surface of said spigot, said gasket cooperating with the inwardly protruding shoulder of said bell end for forcing the raised portion of said locking hook into said locking slot.

Claim 8

A bell and spigot joint for connecting two pipes together, said joint comprising: a. a bell end having at least one helical groove formed in its internal surface and directed inwardly from its free end and an inwardly protruding annular shoulder spaced longitudinally inwardly from said groove, said groove including a forward most side wall extending into said bell end at an angle between approximately 30* and approximately 90* with respect to the internal surface of said bell end; b. a spigot having at least one outwardly protruding helical rib formed on its external surface, directed inwardly from its free end and adapted to cooperate with said helical groove of said bell end for connecting the bell end and spigot together in a threaded fashion, said rib including a rearward most shoulder extending outwardly from the external surface of said spigot at an angle between approximately 30* and approximately 90* with respect to the external surface of said spigot, said shoulder being adapted to abut against said side wall of said helical groove in response to longitudinal forces tending to pull said bell end and spigot away from one another once the latter are threaded together; and c. means for locking said bell end and spigot together once the latter are joined together in said threaded fashion, said locking means including a locking slot formed in the internal surface of said bell end and extending from the rearward most end of said helical groove towards the outermost end thereof, a cooperating raised hook portion located adjacent the forward most end of said helical rib and adapted to engage within said locking groove after said bell end and spigot have been connecteD together in said threaded fashion and means for forcing said raised portion into said locking groove after said bell end and spigot have been threaded together, said forcing means including a resilient annular gasket positioned within a circumferential groove formed around the external surface of said spigot, said gasket cooperating with the inwardly protruding shoulder of said bell end for forcing the raised portion of said locking hook into said locking slot.

Claim 9

A bell and spigot joint according to claim 6 wherein said bell end includes four helical grooves substantially equally circumferentially spaced about the internal surface of said bell end and wherein said spigot includes four helical ribs substantially equally circumferentially spaced about the external surface of said spigot.

Claim 10

A plastic pipe arrangement comprising: a. a first plastic pipe section having an end portion, at least one helical groove formed in the internal surface of said end portion and a slot formed in the internal surface of said end portion and extending from a predetermined point at said groove toward the forward most end of said end portion; b. a second cooperating plastic pipe section having an end portion with an outer diameter slightly less than the inner diameter of said end portion of said first plastic pipe section, said end portion of said second plastic pipe section including at least one helical rib integrally formed on and protruding outwardly from its external surface, said helical rib being adapted to cooperate with said helical groove of said first plastic pipe section for connecting said pipe sections together in a threaded fashion and a raised hook portion located at a predetermined point along said rib and extending away from the forward most end of the end portion of said second section, said hook portion and slot being adapted to mate with one another after said pipe sections have been threaded together so as to interlock said sections to one another; and c. means for automatically forcing said pipe sections longitudinally away from one another after said sections have been threaded together whereby to cause said slot and raised hook to mate with one another, said means also providing a seal between said pipe sections.

Claim 11

A plastic pipe arrangement comprising: a. a first plastic pipe section having an end portion, at least one helical groove formed in the internal surface of said end portion and a slot formed in the internal surface of said end portion and extending from a predetermined point at said groove toward the forward most end of said end portion; b. a second cooperating plastic pipe section having an end portion with an outer diameter slightly less than the inner diameter of said end portion of said first plastic pipe section, said end portion of said second plastic pipe section including at least one helical rib integrally formed on and protruding outwardly from its external surface, said helical rib being adapted to cooperate with said helical groove of said first plastic pipe section for connecting said pipe sections together in a threaded fashion and a raised hook portion located at a predetermined point along said rib and extending away from the forward most end of the end portion of said second section, said hook portion and slot being adapted to mate with one another after said pipe sections have been threaded together so as to interlock said sections to one another; and c. means for automatically forcing said pipe sections longitudinally away from one another after said sections have been threaded together whereby to cause said slot and raised hook to mate with one another, said means also providing a seal between said pipe sections.

Claim 12

A plastic pipe arrangement comprising: a. a first plastic pipe section having an end portion including an inner surface and an outer surface; b. a second plastic pipe section having an end portion including an inner surface and an outer surface, said end portion of said second pipe section having an outer diameter slightly less than the inner diameter of the end portion of said first pipe section; c. means for thread connecting said pipe sections together, said means including i. at least one helical groove formed in a preselected one of said inner and outer surfaces of the end portion of a preselected one of said pipe sections, ii. at least one helical rib integrally formed on and protruding from a preselected different one of said inner and outer surfaces of the end portion of the other one of said pipe sections, d. said preselected surfaces being chosen and said helical groove and helical rib being shaped such that said rib is adapted to cooperate with said groove for connecting said pipe sections together in a threaded fashion; e. said preselected pipe section including said helical groove further including a slot formed in the same preselected surface as said groove and extending from a predetermined point at said groove toward the forward most end of the end portion associated with said groove; f. said preselected pipe section including said helical rib further including a protruding hook portion located at a predetermined point along said rib and extending away from the forward most end of the end portion associated with said rib, said hook portion and slot being adapted to mate with one another after said pipe sections have been threaded together so as to interlock said sections to one another; and g. means for automatically forcing said pipe sections longitudinally away from one another after said sections have been threaded together, whereby to cause said slot and hook portion to mate with one another, said means also providing a seal between said pipe sections.

Claim 13

A plastic pipe arrangement comprising: a. a first plastic pipe section having an end portion including an inner surface and an outer surface; b. a second plastic pipe section having an end portion including an inner surface and an outer surface, said end portion of said second pipe section having an outer diameter slightly less than the inner diameter of the end portion of said first pipe section; c. means for thread connecting said pipe sections together, said means including i. at least one helical groove formed in a preselected one of said inner and outer surfaces of the end portion of a preselected one of said pipe sections, ii. at least one helical rib integrally formed on and protruding from a preselected different one of said inner and outer surfaces of the end portion of the other one of said pipe sections, d. said preselected surfaces being chosen and said helical groove and helical rib being shaped such that said rib is adapted to cooperate with said groove for connecting said pipe sections together in a threaded fashion; e. said preselected pipe section including said helical groove further including a slot formed in the same preselected surface as said groove and extending from a predetermined point at said groove toward the forward most end of the end portion associated with said groove; f. said preselected pipe section including said helical rib further including a protruding hook portion located at a predetermined point along said rib and extending away from the forward most end of the end portion associated with said rib, said hook portion and slot being adapted to mate with one another after said pipe sections have been threaded together so as to interlock said sections to one another; and g. means for automatically forcing said pipe sections longitudinally away from one another after said sections have been threaded together, whereby to cause said slot and hook portion to mate with one another, said means also providing a seal between said pipe sections.