摘要:
An insulating cover is disclosed for enclosing an opening in a building floor containing a folding stairs which has a pair of tracks mounted adjacent the opening. An inverted box-like structure of sufficient size to cover the opening has sides which fit and are movable in the tracks to enable the box-like structure to be slid horizontally and/or pivoted to cover or expose the openings.
摘要:
A priorly used drop wire having a single layer of PVC insulating compound, containing a relatively-expensive epoxy additive, extruded over a spaced pair of conductors, having relatively rough surfaces, is replaced with drop wire having less-costly, relatively-smooth, drawn, conductors onto which spaced, unplasticized particles of PVC resin are coated and the portions of the particles contacting the surfaces of the conductors are melted, caused to undergo controlled degradation and adhere to the surface of the conductor, and thus form a relatively-stable, texturized, discontinuous coating of adhesion sites on the surfaces of the conductors with interdispersed portions of the surfaces being exposed.Over the precoated conductors, a composition containing a plasticized PVC resin may be extruded to form an insulating covering having a relatively-stable, controlled-degree of adhesion to the adhesion sites and the interdispersed, exposed surfaces of the conductors.A precoated metallic strand having a texturized, discontinuous coating of degradated, unplasticized plastic adhesion sites formed on selected portions of the surface of the metallic strand may be used as an article of manufacture onto which an adherent coating of compound containing plasticized plastic may be molded to make other items such as plastic-coated fencing material.
摘要:
In the manufacture of cordage (25), at least two groups (28, 29) of individually insulated, flexible conductors (21--21) which comprise a planar array (40) are moved through a core tube (71) of an extruder (27) in adjacent paths. As the groups are moved out of an exit portion of the core tube where they are spaced apart a predetermined distance and along converging paths to a die, a first plastic material is flowed about the array to enclose it and to be formed into a jacket by the die. Portions of the first plastic material flow between the groups to achieve an equilibration of pressure in the plastic material about each group, which controls the direction and magnitude of lateral movement of each group within the plane of the array, and to form a web (41) which is integral with the jacket and which may vary in thickness along its length to compensate for changes in the outside diameter of the insulated conductors. The control of the lateral movement of each group between the core tube and the die and the formation of a web results in a jacket having substantial symmetry and in cordage having the groups separated by the web which has a thickness that is substantially less than the predetermined distance. The jacket is coated with a second plastic material which has a stiffness modulus that is substantially greater than that of the first plastic material.
摘要:
Superior top coatings for PVC are polyesters, especially a polyester blend of a terpolymer of tetramethylene glycol reacted with terephthalic acid, isophthalic acid, and azelaic acid, and a copolymer of ethylene glycol reacted with terephthalic acid and sebasic acid.
摘要:
A priorly used drop wire having a single layer of PVC insulating compound, containing a relatively-expensive epoxy additive, extruded over a spaced pair of conductors, having relatively rough surfaces, is replaced with drop wire having less-costly, relatively-smooth, drawn, conductors onto which spaced, unplasticized particles of PVC resin are coated and the portions of the particles contacting the surfaces of the conductors are melted, caused to undergo controlled degradation and adhere to the surface of the conductor, and thus form a relatively-stable, texturized, discontinuous coating of adhesion sites on the surfaces of the conductors with interdispersed portions of the surfaces being exposed.Over the precoated conductors, a composition containing a plasticized PVC resin may be extruded to form an insulating covering having a relatively-stable, controlled-degree of adhesion to the adhesion sites and the interdispersed, exposed surfaces of the conductors.A precoated metallic member having a texturized, discontinuous coating of degradated, unplasticized plastic adhesion sites formed on selected portions of the surface of the metallic member may be used as an article of manufacture onto which an adherent coating of compound containing plasticized plastic may be molded to make other items such as plastic-coated fencing material or aluminum siding.
摘要:
In the manufacture of cordage (25), at least two groups (28, 29) of individually insulated, flexible conductors (21--21) which comprise a planar array (40) are moved through a core tube (71) of an extruder (27) in adjacent paths. As the groups are moved out of an exit portion of the core tube where they are spaced apart a predetermined distance and along converging paths to a die, a first plastic material is flowed about the array to enclose it and to be formed into a jacket by the die. Portions of the first plastic material flow between the groups to achieve an equilibration of pressure in the plastic material about each group, which controls the direction and magnitude of lateral movement of each group within the plane of the array, and to form a web (41) which is integral with the jacket and which may vary in thickness along its length to compensate for changes in the outside diameter of the insulated conductors. The control of the lateral movement of each group between the core tube and the die and the formation of a web results in a jacket having substantial symmetry and in cordage having the groups separated by the web which has a thickness that is substantially less than the predetermined distance. The jacket is coated with a second plastic material which has a stiffness modulus that is substantially greater than that of the first plastic material.
摘要:
An insulation comprising a polyether polyester thermoplastic copolymer obtained by reacting 1,4 butane diol terephthalate with terephthalate esters of polytetramethylene glycol is coated over an irregularly configured conductor, such as for example, a tinsel conductor, suitable for use in telecommunications cordage by moving the copolymer through an extruder and along a flow path formed between a core tube and wall of a die cavity. The die cavity adjacent to the throat of the die has a frustoconical portion formed with an approach angle of sufficient magnitude to minimize the pressure drop through the extruder to extrude the copolymer at a temperature slightly above the melting point of the copolymer. The copolymer is insulation tubed over the tinsel conductor with a gas at a controlled volume rate of flow being moved through the core tube along with the tinsel conductor to expand the copolymer extrudate as it flows out of the die opening to cool the extrudate and to facilitate advantageously oriented crystalline growth of the copolymer. Subsequently, the insulation is drawn down about the tinsel conductor with a slight spacing therefrom while treating the insulation with water at a predetermined temperature to anneal the insulation in a predetermined manner. A plurality of the insulated tinsel conductors are enclosed in a jacket which comprises a plasticized polyvinyl chloride composition.
摘要:
An extrusion system is provided for covering a conductor (14) with a crystalline thermoplastic elastomer insulating material. The plastic material is tubed onto the conductor by apparatus which includes a core tube (61) that is mounted in an extruder crosshead (41) such that its free end is positioned within the interior of a die (81, 101) and is spaced from an orifice of the die a predetermined percentage of the land length of the die. A flow passage between the core tube (61) and a wall which defines the die cavity is controlled in accordance with the relative value of the thermal energy which is released by the insulating material at the onset of crystallization. In one arrangement, which has been found to be suitable for a crystalline thermoplastic elastomer having a relatively high value of released thermal energy, the die cavity and the core tube are arranged to provide a gradually converging path toward the die opening. For an insulating material having a relatively low value of released thermal energy, the flow passage is modified to provide a diverging portion (105) and then a rapidly converging portion (110) which communicates with the land of the die.
摘要:
In the manufacture of cordage (25), at least two groups (28, 29) of individually insulated, flexible conductors (21--21) which comprise a planar array (40) are moved through a core tube (71) of an extruder (27) in adjacent paths. As the groups are moved out of an exit portion of the core tube where they are spaced apart a predetermined distance and along converging paths to a die, a first plastic material is flowed about the array to enclose it and to be formed into a jacket by the die. Portions of the first plastic material flow between the groups to achieve an equilibration of pressure in the plastic material about each group, which controls the direction and magnitude of lateral movement of each group within the plane of the array, and to form a web (41) which is integral with the jacket and which may vary in thickness along its length to compensate for changes in the outside diameter of the insulated conductors. The control of the lateral movement of each group between the core tube and the die and the formation of a web results in a jacket having substantial symmetry and in cordage having the groups separated by the web which has a thickness that is substantially less than the predetermined distance. The jacket is coated with a second plastic material which has a stiffness modulus that is substantially greater than that of the first plastic material.
摘要:
A polymeric composition is disclosed. The composition comprises a solid halide polymer, selected from vinyl halide polymers and vinylidene halide polymers, a terpolymer comprising by weight (a) 40 to 80 percent ethylene, (b) 3 to 30 percent carbon monoxide and (c) 5 to 60 percent of one or more monomers copolymerizable therewith in order to produce solid copolymers and a mixture comprising (a') a mixed alkyl phthalate and (b') a copolymer of from about 5 to about 95 percent by weight of an alkyl acrylate wherein the alkyl radical contains from 1 to 12 carbon atoms and from about 95 to about 5 percent by weight of a dissimilar alkyl acrylate wherein the alkyl radical contains from 3 to 24 carbon atoms, the alkyl phthalate being present in an amount by weight at least equal to the amount of the copolymer (b').