Title of Invention

"COMPOSITE REINFORCED GROOVED RUBBER SOLE PLATE FOR RAILWAY TRACK"

Abstract

A composite reinforced grooved rubber sole plate for railway track, particularly the rail pad comprises of the vulcanized rubber of high crosslink density reinforced and bounded by specially engineered polymer in such a way that it restricts the lateral movements of the pad on application of shear and compressive stress thereby preventing the wear and tear of the pad, which increases the service life by many folds.

Full Text

FIELD OF THE INVENTION: The invention relates to composite reinforced grooved rubber sole plate for railway track particularly the rail pad used between metal rails and the concrete sleeper for multiple reasons including electrical insulation, shock absorption, noise reduction and for overall dampening effect. BACKGROUND OF THE INVENTION: hi early days wooden sleepers were used in laying the railway track. Gradually wood became scarce and pre-stressed concrete sleeper replaced the wooden sleeper, which gave rise to the development of Grooved Rubber Sole Plate commonly known as Rail Pad because the concrete sleeper did not have the same inherent dampening properties of wood material. A general assembly of Metal Rail Comprises of Rail Pad, used between the concrete sleeper and steel rail in the track fastening assembly along with GFN Liner, Elastic Rail Clip and Metal Insert as stated in Fig. 1. The existing rail pad used by Indian Railways has following shortcomings: (a) High creep and set: The rubber chain molecules are linked together by chemical cross-linking, which is know as vulcanization. These cross links are never perfect so that under stress there is a very slow break down causing a creep or gradual increase in stretch. Under steady load the deformation of vulcanized rubber increases continuously with time. This phenomenon is known as "CREEP". When the deformation force is removed this creep is represented by a small irreversible deformation known as permanent set. The pads are reported to have deformed much before the expected life of the rail pad. On having this high creep and set the pads tend to skip out of the rail assembly as stated in Fig. 2. (b)Poor shear strength in dynamic condition: Pads are reported to have torn off on repeated load of passing goods or passenger train. It has been observed that creep at ordinary temperatures is considerably increased by mechanical vibration of rubber. Due to this non-performance of the rail pad, the pad deforms and looses the original shape and gets displaced from its designed position making the assembly hazardous as stated in Fig. 3. (c) Poor Compressive strength: CREEP occurs wherever rubber is subjected to stress whether in compression, tension or shear, the pad does not have sufficient compressive strength due to which it disintegrates under pressure ad shape is deformed. (d) Overall Poor Service Life: Due to the above problems the pads have to be replaced much before the minimum expected life of the rail pad resulting in down time of the line and additional cost of replacement. Net negative effect to railways is multifold: a. Compromised safety working standards b. Lower traffic output resulting in loss of revenue, due to downtime of track because of regular replacement c. Increased expenditure of procuring more rail pads d. Increased running cost on account of cost of replacement The good performing rail pad must comply the following requirements for efficient service, such as, (a) High Physical properties, (b) High Ageing Resistance, (c) Electrical Insulation Resistance, (d) Excellent Vibration Damping Properties and (e) Excellent Creep Resistance. The rail pad has to perform in severe weather conditions of varying temperature, humidity under shear and compressive stress in dynamic and static conditions. So a high performing rail pad with the desired working life is required for long lasting under these conditions, as replacement of the standard rail pad is extremely costly and time consuming. The pad has to perform its entire designed requirement so that it does not in any circumstances, compromise the safety of the railways. OBJECT OF THE INVENTION The object of the invention is to manufacture high performance rail pad with all the improved properties for the purpose of safety and cost saving. The further object of the invention is to manufacture the rail pad with enhanced service-life so that the replacement does not require frequently. The further object of the invention is to create rail pad with optimum shear and compressive strength in static and dynamic conditions with high set and creep resistance. The further object o the invention is to manufacture rail pad in such a way 'hat it can tolerate severe weather conditions of varying temperature. STATEMENT OF INVENTION: The present invention tries to overcome the defects in prior art to achieve best performing rail pad for meeting the market demand with respect to the safety and cost effectiveness. This is achieved primarily in four ways; (i) Increasing cross-link density (ii) Introducing filler to rubber cross-link (iii) Reinforcing top and bottom surface of the pad with high strength engineered plastic, where by it restricts gradual increase in stretch under stress and thereby provide in reducing "Creep" (iv) Improving ageing resistance According to this invention the vulcanization of unique polymers of high degree of association and cross-link density on which the creep strongly dependent is performed. The composite material comprises of the vulcanized rubber and engineering plastic, replaces the conventional pad of predetermined design enhances shear and compressive strength and improves creep and set resistance by way of enhancing the service life. The creep process that takes place due to chemical (Oxidative) attack rather than to delay molecular motions is controlled by the use of engineered plastic by way of subdued oxidation, effecting the enhancement of service life. A composite reinforced grooved rubber sole plate for railway track is manufactured with the vulcanized rubber of high cross-link density reinforced and bounced by specially engineered polymer in such a way that it restricts the latera' movements of the pad on application of shear and compressive stress. DESCRIPTION OF THE INVENTION: The invention is described with reference to the accompanying drawings: Fig. 1: Shows track fastening assembly and the position of rubber pad used presently. Fig. 2: Shows the high creep and set, poor compressive strength Fig. 3: Shows wear and tear of rail pad currently used Fig. 4: Shows construction and design of invented pad In the present invention the rail pad is reinforced and bounded by specially engineered polymer in such a way that it restricts the lateral movements of the pad on application of shear and compressive stress thereby preventing the wear and tear of the pad, which increases the service life by many folds. The high strength engineering plastic includes nylon cord/fabric and/or other polymers to achieve the said properties. The rubbers of cross-linking characters for vulcanization are selected from the rubbers commonly available in the market and the fillers, which are used in this process for vulcanization, are selected from the available fillers. The appropriate selection & proportion of the forgoing materials is the key factor in the development of this product. Different embodiments of the invention are possible to achieve the best method of performance and to obtain the composite reinforced grooved rubber sole plate for railway track. It will be understood that skilled persons with many modifications, variations and adaptations may carry out the invention into practice without departing from its sprit or exceeding the scope of claims in describing the invention for the purpose of illustration. We claim: 1. A composite reinforced grooved rubber sole plate for railway track comprising a reinforced vulcanized rubber plate with high cross-linked density characterized in that the said vulcanized rubber plate is bound by engineered polymer as herein defined to restrict the lateral movement of the plate on application of sheer and compressive stress. 2. A composite reinforced grooved rubber sole plate for railway track as claimed in claim 1 wherein the said engineered polymer is nylon cord/ fabric. 3. A composite reinforced grooved rubber sole plate for railway track as claimed in claim 1 wherein the said engineered polymer is polyester cord/ fabric. 4. A composite reinforced grooved rubber sole plate for railway track substantially as herein described with reference to the accompanying drawings.

Documents:

1349-del-2003-abstract.pdf

1349-del-2003-claims cancelled.pdf

1349-del-2003-claims.pdf

1349-del-2003-complete specification(granted).pdf

1349-del-2003-correspondence-others.pdf

1349-del-2003-correspondence-po.pdf

1349-del-2003-description (complete).pdf

1349-del-2003-drawings.pdf

1349-del-2003-form-1.pdf

1349-del-2003-form-13.pdf

1349-del-2003-form-19.pdf

1349-del-2003-form-2.pdf

1349-del-2003-form-3.pdf

1349-del-2003-form-62.pdf

1349-del-2003-gpa.pdf