Method for making power transmission belting

Claim 1

A method for making power transmission belting from an uncured elastomeric belt body having at least one stable length tensile member embedded in the body, comprising the steps of: concentrically assembling the belt body adjacent an inwardly disposed metal mandrel, said metal having a coefficient of thermal expansion of at least about 10 × 10 -6 per ° F; heating said mandrel and causing it to expand against the belt body and to maintain the stable length tensile member under tension; subjecting said belt body to pressure in a direction toward said mandrel; supplying heat units to the belt body beginning preferentially at that portion of the belt body adjacent the metal mandrel and then outwardly toward the remaining portions of the belt body away from the metal mandrel, to establish a heating gradient across the belt body to ensure maintenance of the tensile member under tension; and while maintaining the tensile member in tension, curing said belt body.

Claim 2

A method for making power transmission belting from an uncured elastomeric belt body having at least one stable length tensile member embedded in the body, comprising the steps of: concentrically assembling the belt body adjacent an inwardly disposed metal mandrel, said metal having a coefficient of thermal expansion of at least about 10 × 10 -6 per ° F; heating said mandrel and causing it to expand against the belt body and to maintain the stable length tensile member under tension; subjecting said belt body to pressure in a direction toward said mandrel; supplying heat units to the belt body beginning preferentially at that portion of the belt body adjacent the metal mandrel and then outwardly toward the remaining portions of the belt body away from the metal mandrel, to establish a heating gradient across the belt body to ensure maintenance of the tensile member under tension; and while maintaining the tensile member in tension, curing said belt body.

Claim 9

A method for making power transmission belting comprising the steps of: forming a sleeve belt preform by plying superimposed rubber layers in which is embedded a stable length tensile member, onto a building drum, said preform having a given inside circumference; removing the belt preform from the building drum: positioning the belt preform outwardly adjacent a metal cylinder mandrel having an outside circumference less than the inside circumference of the preform at ambient temperatures, but greater than the inside circumference of the preform at curing temperatures, said metal having a coefficient of thermal expansion of at least about 10 × 10 -6 per ° F.; positioning an expandable bladder adjacent the outer surface of the belt preform, said bladder pressurizable from an associated chamber; heating said mandrel to raise its temperature sufficiently to cause it to expand against the belt preform and to place the stable length tensile member in tension; introducing a heat and pressure source into the bladder and raising the pressure of the source to exert pressure against the belt preform in a direction toward said mandrel but insufficient to place the tensile member in compression; conducting said heating of the mandrel and bladder so as to preferentially supply greater heat units initially to the belt preform adjacent the metal mandrel as compared with the heat units supplied initially to that portion of the belt preform adjacent the bladder, to define a heating gradient across the belt preform; and while maintaining the tensile member in tension, curing said belt preform.

Claim 10

A method for making power transmission belting comprising the steps of: forming a sleeve belt preform by plying superimposed rubber layers in which is embedded a stable length tensile member, onto a building drum, said preform having a given inside circumference; removing the belt preform from the building drum: positioning the belt preform outwardly adjacent a metal cylinder mandrel having an outside circumference less than the inside circumference of the preform at ambient temperatures, but greater than the inside circumference of the preform at curing temperatures, said metal having a coefficient of thermal expansion of at least about 10 × 10 -6 per ° F.; positioning an expandable bladder adjacent the outer surface of the belt preform, said bladder pressurizable from an associated chamber; heating said mandrel to raise its temperature sufficiently to cause it to expand against the belt preform and to place the stable length tensile member in tension; introducing a heat and pressure source into the bladder and raising the pressure of the source to exert pressure against the belt preform in a direction toward said mandrel but insufficient to place the tensile member in compression; conducting said heating of the mandrel and bladder so as to preferentially supply greater heat units initially to the belt preform adjacent the metal mandrel as compared with the heat units supplied initially to that portion of the belt preform adjacent the bladder, to define a heating gradient across the belt preform; and while maintaining the tensile member in tension, curing said belt preform.

Claim 15

A method for producing power transmission belting from an uncured elastomeric belt body having at least one stable length tensile member embedded in the body to define a tensile section embedded in the body, comprising the steps of: concentrically assembling the belt body adjacent an inwardly disposed metal mandrel, said metal having a coefficient of thermal expansion of at least about 10 × 10 -6 per ° F.; positioning an expandable bladder adjacent the outer surface of the belt body, said bladder pressurizable from an associated chamber; said tensile section of the belt body being disposed more closely to the inwardly disposed metal mandrel than the outwardly disposed expandable bladder; heating said mandrel and causing it to expand against the belt body and to maintain the stable length tensile member under tension; introducing heat and pressure into the bladder to supply heat units and exert pressure against the belt body in a direction toward said mandrel but insufficient to place the tensile member in compression; conducting said heating of the mandrel and bladder so as to preferentially supply greater heat units to the belt body adjacent the metal mandrel as compared with the heat units supplied to that portion of the belt body adjacent the bladder, to define a heating gradient across the belt body; and while maintaining the tensile member in tension, curing said belt body.

Claim 16

A method for producing power transmission belting from an uncured elastomeric belt body having at least one stable length tensile member embedded in the body to define a tensile section embedded in the body, comprising the steps of: concentrically assembling the belt body adjacent an inwardly disposed metal mandrel, said metal having a coefficient of thermal expansion of at least about 10 × 10 -6 per ° F.; positioning an expandable bladder adjacent the outer surface of the belt body, said bladder pressurizable from an associated chamber; said tensile section of the belt body being disposed more closely to the inwardly disposed metal mandrel than the outwardly disposed expandable bladder; heating said mandrel and causing it to expand against the belt body and to maintain the stable length tensile member under tension; introducing heat and pressure into the bladder to supply heat units and exert pressure against the belt body in a direction toward said mandrel but insufficient to place the tensile member in compression; conducting said heating of the mandrel and bladder so as to preferentially supply greater heat units to the belt body adjacent the metal mandrel as compared with the heat units supplied to that portion of the belt body adjacent the bladder, to define a heating gradient across the belt body; and while maintaining the tensile member in tension, curing said belt body.

Claim 17

The method of method of 1 including the additional step, after curing the belt body, of: rapidly cooling the mandrel to cause it to contract away from the cured belt body and thereafter removing the cured belt body from the mandrel.

Claim 18

The method of method of 1 including the additional step, after curing the belt body, of: rapidly cooling the mandrel to cause it to contract away from the cured belt body and thereafter removing the cured belt body from the mandrel.

Claim 20

A method for producing power transmission belting comprising the steps of: forming a sleeve belt preform by applying superimposed rubber layers in which is embedded a stable length tensile member, onto a building drum, said preform having a given inside circumference and said stable length tensile member varying no more than about 0.50 percent in length during subsequent curing; positioning the belt preform outwardly adjacent a metal cylinder mandrel having an outside circumference less than the inside circumference of the preform at ambient temperatures, but greater than the inside circumference of the preform at curing temperatures, said metal having a coefficient of thermal expansion of at least about 13.5 × 10 -6 per ° F.; positioning an expandable bladder adjacent the outer surface of the belt preform, said bladder pressurizable from an associated chamber; said stable length tensile member being positioned substantially closer to said mandrel than said expandable bladder; heating said mandrel to raise its temperature sufficiently to cause it to expand against the belt preform and to place the stable length tensile member in tension; introducing a heat and pressure source into the bladder and raising the pressure of the source to exert pressure against the belt preform in a direction toward said mandrel but insufficient to place the tensile member in compression; conducting said heating of the mandrel and bladder as to preferentially supply greater heat units to the belt preform adjacent the metal mandrel as compared with heat units supplied to that portion of the belt preform adjacent the bladder, to define a heating gradient across the belt preform; while maintaining the tensile member in tension, curing said belt preform; and while the mandrel is still hot and in its expanded form, immersing the mandrel with the cured belt sleeve thereon in a cooling fluid medium to cause the mandrel temperature to be lowered and the mandrel to contract whereby the necessary clearance is provided for easily sliding the cured belt preform from the mandrel.

Claim 21

A method for producing power transmission belting comprising the steps of: forming a sleeve belt preform by applying superimposed rubber layers in which is embedded a stable length tensile member, onto a building drum, said preform having a given inside circumference and said stable length tensile member varying no more than about 0.50 percent in length during subsequent curing; positioning the belt preform outwardly adjacent a metal cylinder mandrel having an outside circumference less than the inside circumference of the preform at ambient temperatures, but greater than the inside circumference of the preform at curing temperatures, said metal having a coefficient of thermal expansion of at least about 13.5 × 10 -6 per ° F.; positioning an expandable bladder adjacent the outer surface of the belt preform, said bladder pressurizable from an associated chamber; said stable length tensile member being positioned substantially closer to said mandrel than said expandable bladder; heating said mandrel to raise its temperature sufficiently to cause it to expand against the belt preform and to place the stable length tensile member in tension; introducing a heat and pressure source into the bladder and raising the pressure of the source to exert pressure against the belt preform in a direction toward said mandrel but insufficient to place the tensile member in compression; conducting said heating of the mandrel and bladder as to preferentially supply greater heat units to the belt preform adjacent the metal mandrel as compared with heat units supplied to that portion of the belt preform adjacent the bladder, to define a heating gradient across the belt preform; while maintaining the tensile member in tension, curing said belt preform; and while the mandrel is still hot and in its expanded form, immersing the mandrel with the cured belt sleeve thereon in a cooling fluid medium to cause the mandrel temperature to be lowered and the mandrel to contract whereby the necessary clearance is provided for easily sliding the cured belt preform from the mandrel.

Claim 22

A method for producing in inverted manner molded notch elastomeric power transmission belting from an uncured belt body having an intermediately disposed tensile section formed of stable length tensile members, an elastomeric overcord section adjacent one side of the tensile section, and an elastomeric undercord section adjacent the other side of the tensile section, the steps comprising: concentrically assembling the belt body with the overcord section immediately adjacent an inwardly disposed metal mandrel, said metal having a coefficient of thermal expansion of at least about 10 × 10 -6 per ° F; positioning an expandable cylindrical elastomeric bladder having notches formed therein extending axially with respect to the cylinder so that the notches are positioned adjacently facing the undercord section of the belt body, said bladder pressurizable for movement toward the belt body; heating said mandrel to raise its temperature sufficiently to cause it to expand against the belt body overcord section and to place the stable length tensile member in tension; pressurizing the bladder to thereby exert molding pressure by the notched bladder against the belt body undercord and in a direction toward said mandrel but insufficient to place the tensile member in compression; and while maintaining the tensile member in tension, curing said belt body whereby notches are mold formed into the undercord.

Claim 23

A method for producing in inverted manner molded notch elastomeric power transmission belting from an uncured belt body having an intermediately disposed tensile section formed of stable length tensile members, an elastomeric overcord section adjacent one side of the tensile section, and an elastomeric undercord section adjacent the other side of the tensile section, the steps comprising: concentrically assembling the belt body with the overcord section immediately adjacent an inwardly disposed metal mandrel, said metal having a coefficient of thermal expansion of at least about 10 × 10 -6 per ° F; positioning an expandable cylindrical elastomeric bladder having notches formed therein extending axially with respect to the cylinder so that the notches are positioned adjacently facing the undercord section of the belt body, said bladder pressurizable for movement toward the belt body; heating said mandrel to raise its temperature sufficiently to cause it to expand against the belt body overcord section and to place the stable length tensile member in tension; pressurizing the bladder to thereby exert molding pressure by the notched bladder against the belt body undercord and in a direction toward said mandrel but insufficient to place the tensile member in compression; and while maintaining the tensile member in tension, curing said belt body whereby notches are mold formed into the undercord.