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US 12,742,294 B2Granted
Nonwoven fabric-integrated sleeper pad using rubber pad embedded with stiffener and methods of manufacturing and constructing the same
AssigneeKorea Railroad Research Institute
InventorsDae Sang Kim, Ungjin Kim
Life of this patent
Estimating the term…
Abstract
The present disclosure provides, as a sleeper pad for railroad sleepers in which a nonwoven fabric is attached to a rubber pad by a thermal fusion process, a nonwoven fabric-integrated sleeper pad using a rubber pad embedded with a stiffener and methods of manufacturing and constructing the same, which can adjust vertical support stiffness of the rubber pad by the stiffener embedded in the middle of the rubber pad and which can secure the flatness of the rubber pad by resisting bending deformation due to a difference in shrinkage between rubber and nonwoven fabric.
Claims19
A nonwoven fabric-integrated sleeper pad using a rubber pad embedded with a stiffener, the nonwoven fabric-integrated sleeper pad comprising:
- a rubber pad formed of multiple layers including a lower rubber pad and an upper rubber pad, integrated with an attaching nonwoven fabric, and exposed to a bottom surface of a concrete sleeper;
- a stiffener horizontally embedded in the rubber pad;
- and
- the attaching nonwoven fabric configured to come in close contact with a bottom surface of the lower rubber pad of the rubber pad and embedded in the bottom surface of the concrete sleeper,
- wherein the stiffener resists horizontal deformation of the rubber pad to increase vertical stiffness, and the attaching nonwoven fabric is embedded by being pressed toward a surface of concrete placed in a sleeper formwork, and as the placed concrete is cured, the nonwoven fabric-integrated sleeper pad is embedded in the bottom surface of the concrete sleeper to secure an attaching force with the concrete sleeper,
- wherein the rubber pad is cut to be apart from an end of the concrete sleeper,
- wherein the concrete sleeper in which the attaching nonwoven fabric is embedded is a concrete sleeper including an intermediate connecting portion disposed between expansion flanges at both ends, and the nonwoven fabric-integrated sleeper pad which is exposed only to bottom surfaces of the expansion flanges at both ends comes in contact with gravel.
4 more elements
A method of manufacturing a nonwoven fabric-integrated sleeper pad using a rubber pad embedded with a stiffener, the method comprising:
- a) manufacturing ethylene propylene diene monomer compounded rubber in which EPDM and rubber are mixed with a mixer;
- b) winding an attaching nonwoven fabric having a surface made of a dense material around a roll;
- c) manufacturing a lower rubber pad and an upper rubber pad by forming a thin plate in which the ethylene propylene diene monomer compounded rubber is formed into a sheet through a calendering process;
- d) mounting and adhering a lattice-shaped stiffener onto the lower rubber pad;
- e) forming a rubber pad embedded with the stiffener by adhering the upper rubber pad to the lower rubber pad by a thermal fusion process;
- f) bringing the attaching nonwoven fabric in close contact with a bottom surface of the rubber pad embedded with the stiffener;
- g) by, through a rotor curing process, heating and pressing the lower rubber pad in close contact with the attaching nonwoven fabric, allowing the attaching nonwoven fabric and the lower rubber pad to be entangled on a close contact surface and mechanically coupled;
- h) allowing the attaching nonwoven fabric and the lower rubber pad to be integrated by a chemical bonding process as the close contact surface between the attaching nonwoven fabric and the lower rubber pad is melted and diffused due to vulcanization;
- and
- i) cutting the rubber pad, with which the nonwoven fabric is in close contact by being mechanically coupled and chemically bonded thereto, in a predetermined size to form the nonwoven fabric-integrated sleeper pad,
- wherein the stiffener is horizontally embedded in the rubber pad to resist horizontal deformation of the rubber pad and increase vertical stiffness, and the attaching nonwoven fabric is embedded by being pressed toward a surface of concrete placed in a sleeper formwork, and as the placed concrete is cured, the nonwoven fabric-integrated sleeper pad is embedded in a bottom surface of the concrete sleeper to secure an attaching force with the concrete sleeper,
- wherein the rubber pad is cut to be apart from an end of the concrete sleeper,
- wherein the concrete sleeper in which the attaching nonwoven fabric is embedded is a concrete sleeper including an intermediate connecting portion disposed between expansion flanges at both ends, and the nonwoven fabric-integrated sleeper pad which is exposed only to bottom surfaces of the expansion flanges at both ends comes in contact with gravel.
10 more elements
A method of constructing a nonwoven fabric-integrated sleeper pad using a rubber pad embedded with a stiffener, the method comprising:
- a) forming a nonwoven fabric-integrated sleeper pad, with which an attaching nonwoven fabric is in close contact, on a bottom surface of a rubber pad embedded with a stiffener;
- b) placing concrete in a sleeper formwork;
- c) pressing a surface of the concrete placed in the sleeper formwork so that the attaching nonwoven fabric of the nonwoven fabric-integrated sleeper pad is embedded;
- d) as the placed concrete is cured, integrating the nonwoven fabric-integrated sleeper pad with a bottom surface of a concrete sleeper;
- and
- e) placing the concrete sleeper having the nonwoven fabric-integrated sleeper pad (100) attached to the bottom surface thereof on a gravel ballast,
- wherein the stiffener of step a) is horizontally embedded in the rubber pad to resist horizontal deformation of the rubber pad and increase vertical stiffness, and the attaching nonwoven fabric is embedded by being pressed toward a surface of concrete placed in the sleeper formwork, and as the placed concrete is cured, the nonwoven fabric-integrated sleeper pad is embedded in a bottom surface of the concrete sleeper to secure an attaching force with the concrete sleeper,
- wherein the rubber pad is cut to be apart from an end of the concrete sleeper,
- wherein the concrete sleeper in which the attaching nonwoven fabric is embedded is a concrete sleeper including an intermediate connecting portion disposed between expansion flanges at both ends, and the nonwoven fabric-integrated sleeper pad which is exposed only to bottom surfaces of the expansion flanges at both ends comes in contact with gravel.
6 more elements
Dependencies are inferred from the claim text.