Method of molding a socket part on a synthetic resinous pipe end

Claim 1

A method of molding a socket part on a first synethetic resinous pipe end wherein a socket part for use in the connection of pipes is molded within one end of said first synethetic resinous pipe, while a filler ring, which fills up a clearance produced between the socket part and an end of a second synthetic resinous pipe inserted in the socket part of said first synthetic resinous pipe, serves in the capacity of stopper to regulate the insertion extent of said second synthetic resinous pipe such that said filler ring is loaded at the same time of the formation of the socket part, comprising the steps of: loading a filler ring, having an external diameter slightly larger than the internal diameter of said socket part which is to be molded, on a core mold including a second wall surface which is built in a member constituting the external circumferential surface of said core mold; holding said filler ring on a holding means provided on said core mold for expanding said filler ring radially from therewithin; inserting a heat softened end of said first synthetic resinous pipe over said core mold and filler ring which is thereby held concentrically and in correct roundness to mold said socket part and to embed said filler ring on the inner surface of said first synthetic resinous pipe; and, removing said core mold while retaining said filler ring within said socket part after the completion of the molding such that said filler ring is arranged between said socket part and said inserted end of said second synthetic resinous pipe wherein said holding means for said filler ring supports said filler ring through the medium both of a shifting member arranged movably on the circumferential surface in the axial direction of said core mold and of a spring ring arranged on the inclined surface of said shifting member, thereby holding said filler ring by the expansion of said spring ring in proportion to the movement of said shifting member.

Claim 2

A method of molding a socket part on a first synethetic resinous pipe end wherein a socket part for use in the connection of pipes is molded within one end of said first synethetic resinous pipe, while a filler ring, which fills up a clearance produced between the socket part and an end of a second synthetic resinous pipe inserted in the socket part of said first synthetic resinous pipe, serves in the capacity of stopper to regulate the insertion extent of said second synthetic resinous pipe such that said filler ring is loaded at the same time of the formation of the socket part, comprising the steps of: loading a filler ring, having an external diameter slightly larger than the internal diameter of said socket part which is to be molded, on a core mold including a second wall surface which is built in a member constituting the external circumferential surface of said core mold; holding said filler ring on a holding means provided on said core mold for expanding said filler ring radially from therewithin; inserting a heat softened end of said first synthetic resinous pipe over said core mold and filler ring which is thereby held concentrically and in correct roundness to mold said socket part and to embed said filler ring on the inner surface of said first synthetic resinous pipe; and, removing said core mold while retaining said filler ring within said socket part after the completion of the molding such that said filler ring is arranged between said socket part and said inserted end of said second synthetic resinous pipe wherein said holding means for said filler ring supports said filler ring through the medium both of a shifting member arranged movably on the circumferential surface in the axial direction of said core mold and of a spring ring arranged on the inclined surface of said shifting member, thereby holding said filler ring by the expansion of said spring ring in proportion to the movement of said shifting member.

Claim 3

A method of molding a socket part on a first synthetic resinous pipe end wherein a socket part for use in the connection of pipes is molded within one end of said first synthetic resinous pipe, while a filler ring, which fills up a clearance produced between the socket part and an end of a second synthetic resinous pipe inserted in the socket part of said first synthetic resinous pipe, serves in the capacity of a stopper to regulate the insertion extent of said second synthetic resinous pipe such that said filler ring is loaded at the same time of the formation of the socket part, comprising the steps of: loading a filler ring, having an external diameter slightly larger than the internal diameter of said socket part which is to be molded, on a core mold including a second wall surface which is built in a member constituting the external circumferential surface of said core mold; holding said filler ring on a holding means provided on said core mold for expanding said filler ring radially from therewithin; inserting a heat softened end of said first synthetic resinous pipe over said core mold and filler ring which is thereby held concentrically and in correct roundness to mold said socket part and to embed said filler ring on the inner surface of said first synthetic resinous pipe; and, removing said core mold while retaining said filler ring within said socket part after the completion of the molding such that said filler ring is arranged between said socket part and said inserted end of said second synthetic resinous pipe wherein said holding means for said filler ring is provided with a plurality of thrust members biased by springs in the protruding direction on the circumference of said core mold where said filler ring is to be arranged, whereby said thrust members expansively hold said filler ring.

Claim 4

A method of molding a socket part on a first synthetic resinous pipe end wherein a socket part for use in the connection of pipes is molded within one end of said first synthetic resinous pipe, while a filler ring, which fills up a clearance produced between the socket part and an end of a second synthetic resinous pipe inserted in the socket part of said first synthetic resinous pipe, serves in the capacity of a stopper to regulate the insertion extent of said second synthetic resinous pipe such that said filler ring is loaded at the same time of the formation of the socket part, comprising the steps of: loading a filler ring, having an external diameter slightly larger than the internal diameter of said socket part which is to be molded, on a core mold including a second wall surface which is built in a member constituting the external circumferential surface of said core mold; holding said filler ring on a holding means provided on said core mold for expanding said filler ring radially from therewithin; inserting a heat softened end of said first synthetic resinous pipe over said core mold and filler ring which is thereby held concentrically and in correct roundness to mold said socket part and to embed said filler ring on the inner surface of said first synthetic resinous pipe; and, removing said core mold while retaining said filler ring within said socket part after the completion of the molding such that said filler ring is arranged between said socket part and said inserted end of said second synthetic resinous pipe wherein said holding means for said filler ring is provided with a plurality of thrust members biased by springs in the protruding direction on the circumference of said core mold where said filler ring is to be arranged, whereby said thrust members expansively hold said filler ring.

Claim 5

A method of molding a socket part on a first synthetic resinous pipe end wherein a socket part for use in the connection of pipes is molded within one end of said first synthetic resinous pipe, while a filler ring, which fills up a clearance produced between the socket part and an end of a second synthetic resinous pipe inserted in the socket part of said first synthetic resinous pipe, serves in the capacity of a stopper to regulate the insertion extent of said second synthetic resinous pipe such that said filler ring is loaded at the same time of the formation of the socket part, comprising the steps of: loading a filler ring, having an external diameter slightly larger than the internal diameter of said socket part which is to be molded, on a core mold including a second wall surface which is built in a member constituting the external circumferential surface of said core mold; holding said filler ring on a holding means provided on said core mold for expanding said filler ring radially from therewithin; inserting a heat softened end of said first synthetic resinous pipe over said core mold and filler ring which is thereby held concentrically and in correct roundness to mold said socket part and to embed said filler ring on the inner surface of said first synthetic resinous pipe; and, removing said core mold while retaining said filler ring within said socket part after the completion of the molding such that said filler ring is arranged between said socket part and said inserted end of said second synthetic resinous pipe wherein said holding means for said filler ring is constructed in such a manner that said filler ring can be held by a plurality of slide pieces provided both along a concave step part which is formed in the circumference of said core mold and along the inclined surface which is formed in said concave step part, and that said slide pieces will be able to hold said filler ring by being expanded in the centrifugal direction through the aid of a shifting annulus provided on the front of the external circumference of said core mold.

Claim 6

A method of molding a socket part on a first synthetic resinous pipe end wherein a socket part for use in the connection of pipes is molded within one end of said first synthetic resinous pipe, while a filler ring, which fills up a clearance produced between the socket part and an end of a second synthetic resinous pipe inserted in the socket part of said first synthetic resinous pipe, serves in the capacity of a stopper to regulate the insertion extent of said second synthetic resinous pipe such that said filler ring is loaded at the same time of the formation of the socket part, comprising the steps of: loading a filler ring, having an external diameter slightly larger than the internal diameter of said socket part which is to be molded, on a core mold including a second wall surface which is built in a member constituting the external circumferential surface of said core mold; holding said filler ring on a holding means provided on said core mold for expanding said filler ring radially from therewithin; inserting a heat softened end of said first synthetic resinous pipe over said core mold and filler ring which is thereby held concentrically and in correct roundness to mold said socket part and to embed said filler ring on the inner surface of said first synthetic resinous pipe; and, removing said core mold while retaining said filler ring within said socket part after the completion of the molding such that said filler ring is arranged between said socket part and said inserted end of said second synthetic resinous pipe wherein said holding means for said filler ring is constructed in such a manner that said filler ring can be held by a plurality of slide pieces provided both along a concave step part which is formed in the circumference of said core mold and along the inclined surface which is formed in said concave step part, and that said slide pieces will be able to hold said filler ring by being expanded in the centrifugal direction through the aid of a shifting annulus provided on the front of the external circumference of said core mold.

Claim 7

A method of molding a socket part on a first synthetic resinous pipe end wherein a socket part for use in the connection of pipes is molded within one end of said first synthetic resinous pipe, while a filler ring, which fills up a clearance produced between the socket part and an end of a second synthetic resinous pipe inserted in the socket part of said first synthetic resinous pipe, serves in the capacity of a stopper to regulate the insertion extent of said second synthetic resinous pipe such that said filler ring is loaded at the same time of the formation of the socket part, comprising the steps of: loading a filler ring, having an external diameter slightly larger than the internal diameter of said socket part which is to be molded, on a core mold including a stepped wall surface which is built in a member constituting the external circumferential surface of said core mold; holding said filler ring on a holding means provided on said core mold for expanding said filler ring radially from therewithin; inserting a heat softened end of said first synthetic resinous pipe over said core mold and filler ring which is thereby held concentrically and in correct roundness to mold said socket part and to embed said filler ring on the inner surface of said first synthetic resinous pipe; and, removing said core mold while retaining said filler ring within said socket part after the completion of the molding such that said filler ring is arranged between said socket part and said inserted end of said second synthetic resinous pipe wherein prior to said step of inserting said end of said first synthetic resinous pipe over said core mold and said step of holding said filler ring concentrically, said first synthetic resinous pipe is concentrically centered and guided in front of the holding means for the filler by guide means and wherein said centering guide means for said first synthetic pipe is constructed so as to support the internal circumference of the inserted pipe by arranging a plurality of members on the top of the core mold so as to be biased to project up at all times.

Claim 8

A method of molding a socket part on a first synthetic resinous pipe end wherein a socket part for use in the connection of pipes is molded within one end of said first synthetic resinous pipe, while a filler ring, which fills up a clearance produced between the socket part and an end of a second synthetic resinous pipe inserted in the socket part of said first synthetic resinous pipe, serves in the capacity of a stopper to regulate the insertion extent of said second synthetic resinous pipe such that said filler ring is loaded at the same time of the formation of the socket part, comprising the steps of: loading a filler ring, having an external diameter slightly larger than the internal diameter of said socket part which is to be molded, on a core mold including a stepped wall surface which is built in a member constituting the external circumferential surface of said core mold; holding said filler ring on a holding means provided on said core mold for expanding said filler ring radially from therewithin; inserting a heat softened end of said first synthetic resinous pipe over said core mold and filler ring which is thereby held concentrically and in correct roundness to mold said socket part and to embed said filler ring on the inner surface of said first synthetic resinous pipe; and, removing said core mold while retaining said filler ring within said socket part after the completion of the molding such that said filler ring is arranged between said socket part and said inserted end of said second synthetic resinous pipe wherein prior to said step of inserting said end of said first synthetic resinous pipe over said core mold and said step of holding said filler ring concentrically, said first synthetic resinous pipe is concentrically centered and guided in front of the holding means for the filler by guide means and wherein said centering guide means for said first synthetic pipe is constructed so as to support the internal circumference of the inserted pipe by arranging a plurality of members on the top of the core mold so as to be biased to project up at all times.

Claim 9

A method of molding a socket part on a first synthetic resinous pipe end wherein a socket part for use in the connection of pipes is molded within one end of said first synthetic resinous pipe, while a filler ring, which fills up a clearance produced between the socket part and an end of a second synthetic resinous pipe inserted in the socket part of said first synthetic resinous pipe, serves in the capacity of a stopper to regulate the insertion extent of said second synthetic resinous pipe such that said filler ring is loaded at the same time of the formation of the socket part, comprising the steps of: loading a filler ring, having an external diameter slightly larger than the internal diameter of said socket part which is to be molded, on a core mold including a stepped wall surface which is built in a member constituting the external circumferential surface of said core mold; holding said filler ring on a holding means provided on said core mold for expanding said filler ring radially from therewithin; inserting a heat softened end of said first synthetic resinous pipe over said core mold and filler ring which is thereby held concentrically and in correct roundness to mold said socket part and to embed said filler ring on the inner surface of said first synthetic resinous pipe; and, removing said core mold while retaining said filler within said socket part after the completion of the molding such that said filler ring is arranged between said socket part and said inserted end of said second synthetic resinous pipe wherein prior to said step of inserting said end of said first synthetic resinous pipe over said core mold and said step of holding said filler ring concentrically, said first synthetic resinous pipe is concentrically centered and guided in front of the holding means for the filler by guide means and wherein said centering guide means for said first synthetic resinous pipe is constructed in such a manner that a plurality of slide pieces are radially arranged so as to be biased by a spring ring in the axial direction of the core mold, while their expansion operation is executed by a ring which expands the respective bases of said slide pieces.

Claim 10

A method of molding a socket part on a first synthetic resinous pipe end wherein a socket part for use in the connection of pipes is molded within one end of said first synthetic resinous pipe, while a filler ring, which fills up a clearance produced between the socket part and an end of a second synthetic resinous pipe inserted in the socket part of said first synthetic resinous pipe, serves in the capacity of a stopper to regulate the insertion extent of said second synthetic resinous pipe such that said filler ring is loaded at the same time of the formation of the socket part, comprising the steps of: loading a filler ring, having an external diameter slightly larger than the internal diameter of said socket part which is to be molded, on a core mold including a stepped wall surface which is built in a member constituting the external circumferential surface of said core mold; holding said filler ring on a holding means provided on said core mold for expanding said filler ring radially from therewithin; inserting a heat softened end of said first synthetic resinous pipe over said core mold and filler ring which is thereby held concentrically and in correct roundness to mold said socket part and to embed said filler ring on the inner surface of said first synthetic resinous pipe; and, removing said core mold while retaining said filler within said socket part after the completion of the molding such that said filler ring is arranged between said socket part and said inserted end of said second synthetic resinous pipe wherein prior to said step of inserting said end of said first synthetic resinous pipe over said core mold and said step of holding said filler ring concentrically, said first synthetic resinous pipe is concentrically centered and guided in front of the holding means for the filler by guide means and wherein said centering guide means for said first synthetic resinous pipe is constructed in such a manner that a plurality of slide pieces are radially arranged so as to be biased by a spring ring in the axial direction of the core mold, while their expansion operation is executed by a ring which expands the respective bases of said slide pieces.

Claim 13

A method of molding a socket part on a first synthetic resinous pipe end wherein a socket part for use in the connection of pipes is molded within one end of said first synthetic resinous pipe, while a filler ring, which fills up a clearance produced between the socket part of said first synthetic resinous pipe, serves in the capacity of a stopper to regulate the insertion extent of said second synthetic resinous pipe such that said filler ring is loaded at the same time of the formation of the socket part, comprising the steps of: loading a filler ring, having an external diameter slightly larger than the internal diameter of said socket part which is to be molded, on a core mold including a stepped wall surface which is built in a member constituting the external circumferential surface of said core mold; holding said filler ring on a holding means provided on said core mold for expanding said filler ring radially from therewithin; expanding said holding means to shift said filler ring in a radial direction; and inserting a heat softened end of said first synthetic resinous pipe over said core mold and filler ring which is thereby held concentrically and in correct roundness by said expanded holding means to mold said socket part; and, removing said core mold while retaining said filler ring within said socket part after the completion of the molding such that said filler ring is arranged between said socket part and said inserted end of said second synthetic resinous pipe.

Claim 14

A method of molding a socket part on a first synthetic resinous pipe end wherein a socket part for use in the connection of pipes is molded within one end of said first synthetic resinous pipe, while a filler ring, which fills up a clearance produced between the socket part of said first synthetic resinous pipe, serves in the capacity of a stopper to regulate the insertion extent of said second synthetic resinous pipe such that said filler ring is loaded at the same time of the formation of the socket part, comprising the steps of: loading a filler ring, having an external diameter slightly larger than the internal diameter of said socket part which is to be molded, on a core mold including a stepped wall surface which is built in a member constituting the external circumferential surface of said core mold; holding said filler ring on a holding means provided on said core mold for expanding said filler ring radially from therewithin; expanding said holding means to shift said filler ring in a radial direction; and inserting a heat softened end of said first synthetic resinous pipe over said core mold and filler ring which is thereby held concentrically and in correct roundness by said expanded holding means to mold said socket part; and, removing said core mold while retaining said filler ring within said socket part after the completion of the molding such that said filler ring is arranged between said socket part and said inserted end of said second synthetic resinous pipe.