Conformable thin-wall shear-resistant coupling and pipe assembly

A conformable push-type thin-wall shear-resistant pipe coupling:

• a. said coupling, when viewed in transverse cross-section, defining a closed, convexly rounded fibure with a wall thickness in the range of about 0.01 D to about 0.06 D, wherein D is the diameter in inches, of the pipe for which the coupling is intended;
• b. said couplings having
• 1. a column expansibility in the range of about 5 .times. 10.sup.-.sup.4 to about 50 .times. 10.sup.-.sup.4 inches per pound, and
• 2. a shear resistance providing about 0.047 inches of pipe deflection or less per inch of D under a shear load of 150 D pounds,
• c. said couplings including a fiber-reinforced elastomer composite containing fibers and elastomer in the range of about 40 to about 60 percent of elastomer based on total weight of fiber and elastomer, for providing the above-indicated column expansibility and shear resistance, said composite including:
• 1. fibers having a modulus of at least about 6 .times. 10.sup.6 psi, oriented in an opposed, balanced helical pattern or patterns at a helix angle in the range of about 50.degree. to about 65.degree., measured from a reference line parallel to the coupling axis, which angle is substantially uniform throughout the length of the coupling in any given layer of said fibers, and
• 2. elastomeric binder of substantially lower modulus than said fibers having a modulus of at least about 50 psi at 100% elongation and at least about 100 psi at 300% elongation, a tensile strength of at least about 600 psi, and a Shore A durometer hardness in the range of about 15 to about 70, for mechanically interconnecting the opposed fibers at the above-indicated helix angle.

A conformable push-type thin-wall shear-resistant pipe coupling:

• a. said coupling, when viewed in transverse cross-section, defining a closed, convexly rounded figure with a wall thickness in the rage of about 0.01 D to about 0.06 D wherein D is the diameter in inches, of the pipe for which the coupling is intended;
• b. said couplings having
• 1. a column expansibility in the range of about 5 .times. 10.sup..sup.-4 to about 50 .times. 10.sup..sup.-4 inches per pound, and
• 2. a shear resistance providing about 0.047 inches of pipe deflection or less per inch of D under a hear load of 150 D pounds,
• 3. a ring flexibility providing a force per unit of deflection, per unit of length, when compressed diametrically, of less than about 15 psi,
• c. said couplings including a fiber-reinforced elastomer composite containing sufficient quantities of fibers and elastomer for providing the above-indicated column expansibility and shear resistance, said composite including:
• 1. a liner layer of elastomeric material of substantially lower modulus than said fibers and having the requisite chemical resistance to substantially withstand attach by acids and alkalis encountered in ordinary domestic sewage systems,
• 2. said fibers having a modulus of at least about 6 .times. 10.sup.6 psi, wound upon said liner layer in an opposed, balanced helical pattern or patterns at a helix angle in the range of about 50.degree. to about 65.degree., measured from a reference line parallel to the coupling axis, which angle is substantially uniform throughout the length of the coupling in any given layer of said fibers, and
• 3. elastomeric binder of substantially lower modulus than said fibers having a modulus of at least about 50 psi at 100% elongation and at least about 100 psi at 300% elongation, a tensile strength of at least about 600 psi, and a Shore A durometer hardness in the range of about 15 to about 70, for mechanically interconnecting the opposed fibers at the above-indicated helix angle, said binder being present in a weight percentage in the range of about 40 to about 60 percent, based on the total weight of the fiber and binder,
• whereby said coupling will enlarge to receive the end of a rigid conduit which is pushed into it and generate pull-out resistance which is in response to and in proportion to pull-out force and which is substantially in excess of that which would be provided by the mere hoop-stress elasticity of the elastomeric material.

A pipe having a conformable push-type thin-wall shear-resistant coupling, comprising

• I. a flexible sleeve coupling
• A. said coupling having a wall thickness in the range of about 0.006 D to about 0.09 D, wherein D is the diameter in inches, of the pipe for which the coupling is intended;
• B. said coupling having
• 1. a column expansibility of at least about 2 .times. 10.sup..sup.-4 inches per pound, and
• 2. a shear resistance providing about 0.12 inches of pipe deflection or less per inch of D under a shear load of 150 D pounds,
• C. said coupling including a fiber-reinforced elastomer composite containing sufficient quantities of fibers and elastomer for providing the above-indicated column expansibility and shear resistance, said composite including:
• 1. fiber having a modulus of at least about 6 .times. 10.sup.6 psi, oriented in an opposed, balanced helical pattern or patterns at a helix angle in the range of about 45.degree. to about 75.degree., measured from a reference line parallel to the coupling axis, which angle is substantially uniform throughout the length of the coupling in any given layer of said fibers, and
• 2. elastomeric binder of substantially lower modulus than said fibers having a modulus at 100% elongation of at least about 25 psi, a tensile strength of at least about 300 psi, and a Shore A durometer hardness in the range of about 15 to about 90, for mechanically interconnecting the opposed fibers at the above-indicated helix angle;
• Ii. a pipe section to which said flexible sleeve is connected in partially overlapping telescoping relationship whereby a free portion of said coupling extends free of said pipe section:
• A. said pipe section, when viewed in transverse cross-section, defining a closed, convexly rounded figure,
• B. said pipe section having sufficient circumferential rigidity so that its circumference will not change more than about 1% on application of 100 pounds per square inch radial pressure thereto, and
• C. said pipe section also having a circumference greater than the inside circumference of the coupling in the range of up to about 8%, to provide an interference fit with said coupling
• whereby upon insertion of another such pipe section into said free portion, said pipe shape, circumferential rigidity and interference fit may coact with said coupling to transfer shear forces from said pipe sections to the fibers in said couplings.

A pipe having a conformable push-type thin-wall shear-resistant coupling, comprising

• I. a flexible sleeve coupling
• A. said coupling having a wall thickness in the range of about 0.01 D to about 0.06 D, wherein D is the diameter in inches, of the pipe for which the coupling is intended;
• B. said coupling having
• 1. a column expansibility in the range of about 5 .times. 10.sup..sup.-4 to about 50 .times. 10.sup..sup.-4 inches per pound, and
• 2. a shear resistance providing about 0.047 inches of pipe deflection or less per inch of D under a shear load of 150 D pounds,
• C. said couplings including a fiber-reinforced elastomer composite containing sufficient quantities of fibers and elastomer in the range of about 40 to about 60 percent of elastomer based on total weight of fiber and elastomer, for providing the above-indicated column expansibility and shear resistance, said composite including:
• 1. fibers having a modulus of at least about 6 .times. 10.sup.6 psi, oriented in an opposed, balanced helical pattern or patterns at a helix angle in the range of about 50.degree. to about 65.degree., measured from a reference line parallel to the coupling axis, which angle is substantially uniform throughout the length of the coupling in any given layer of said fibers, and
• 2. elastomeric binder of substantially lower modulus than said fibers having a modulus of at least about 50 psi at 100% elongation and at least about 100 psi at 300% elongation, a tensile strength of at least about 600 psi, and a Shore A durometer hardness in the range of about 15 to about 70, for mechanically interconnecting the opposed fibers at the above-indicated helix angle;
• Ii. a pipe section to which said flexible sleeve is connected in partially overlapping telescoping relationship whereby a free portion of said coupling extends free of said pipe section:
• A. said pipe section, when viewed in transverse cross-section, defining a closed, convexly rounded figure,
• B. said pipe section having sufficient circumferential rigidity so that its circumference will not change more than about 1% on application of 100 pounds per square inch radial pressure thereto, and
• C. said pipe section also having a circumference greater than the inside circumference of the coupling in the range of up to about 8%, to provide an interference fit with said coupling
• whereby upon insertion of another such pipe section into said free portion, said pipe shape, circumferential rigidity and interference fit may coact with said coupling to transfer shear forces from said pipe sections to the fibers in said couplings.

A conformable thin-wall shear-resistant joint and pipe assembly comprising:

• I. a plurality of flexible push-type couplings into which the ends of adjoining pipe sections have been inserted,
• A. said couplings, when viewed in transverse cross-section, defining a closed, convexly rounded figure with a wall thickness in the range of about 0.006 D to about 0.09 D, wherein D is the nominal diameter of the pipe in inches,
• B. said couplings having
• 1. a column expansibility of at least about 2 .times. 10.sup..sup.-4 inches per pound, and
• 2. a shear resistance providing about 0.12 inches of pipe deflection or less per inch of D under a shear load of 150 D pounds,
• C. said couplings including a fiber-reinforced elastomer composite containing sufficient quantities of fiber and elastomer for providing the above-indicated column expansibility and shear resistance, said composite including:
• 1. fibers having a modulus of at least about 6 .times. 10.sup.6 psi, oriented in an opposed, balanced helical pattern or patterns at a helix angle in the range of about 75.degree. to about 45.degree., measured from a reference line parallel to the coupling axis, which angle is substantially uniform throughout the length of the coupling in any given layer of said fibers, and
• 2. elastomeric binder of substantially lower modulus than said fibers having a modulus at 100% elongation of at least about 25 psi, a tensile strength of at least about 300 psi and a Shore A durometer hardness in the range of about 15 to about 90, for mechanically interconnecting the opposed fibers at the above-indicated helix angle, and
• Ii. a plurality of pipe sections,
• A. said pipe sections, when viewed in transverse cross-section, defining closed, convexly rounded figures,
• B. said pipe sections having sufficient circumferential rigidity so that their circumference will not change more than about 1% on application of 100 pounds per square inch radial pressure thereto,
• C. said pipe sections also having a circumference greater than the inside circumference of the coupling in the range of up to about 8%, to provide an interference fit with said coupling
• whereby said pipe shape, circumferential rigidity and interference fit may coact with said coupling to transfer shear forces from said pipe sections to the fibers in said couplings.