DESC:Field of the Invention

The present invention relates to a side wall for railway coaches, more particularly, the present invention relates to a method for producing side wall for railway coaches for other than metro trains.

Background of the Invention

At present, side walls of railway coaches other than metro trains are made from plurality (upto 17 Nos) of vertical sheets (2m high x 1.2m wide) welded together to form a wall of about 20-22 meters. The size 2m x 1.2m sheets are cut using laser cutter and welded together to form the wall. Necessary Horizontal & vertical reinforcements which form the inner side of the wall are provided for necessary strength and stiffness of the sidewall.

This present method of preparing sidewall has following disadvantages:
1. The time required for production is more as it involves cutting sheets to size and then carefully applying full welding to make upto 17 vertical joints of approx 2m length each.
2. Surface undulations are formed due to high heat input during welding, which gives a poor finish to the wall resulting into poor aesthetics. Therefore, subsequently require heavy putty & paint application thus adding to dead weight.
3. Further, requires periodic maintenance, which adds cost; and idle rolling stock time also results in loss of revenue for the railways.
4. Also, requires to be periodically re-painted after paint stripping making it Eco-unfriendly.

Therefore, there existed a need to provide a method for producing side wall for the trains, which will overcome the drawbacks of the prior art.

Objects of the Invention

Object of the present invention is to provide a method for producing side wall of railway coaches, which has better aesthetics without surface undulation and can be used without paint by using S.S. material with predefined properties, so as to qualify to be a “World Class Coach” standards.

Another object of the present invention is to provide a method for producing side wall of railway coaches, which is cost effective and requires less maintenance with longer life and which is also eco friendly with lower life cycle cost.

Yet another object of the present invention is to provide a method for producing side wall of railway coaches, which requires less time for production, as there is an acute shortage of railway coaches in India, thereby necessitating running rail coaches which have outlived its life thus make them prone to accidents.

One more object of the present invention is to provide a method for producing side wall of railway coaches, which does not require welding in between, therefore maintains strength of the sheet.

Summary of the invention

According to the present invention there is provided a method for producing side wall of railway coaches. The method having step of selecting a sheet with predefined grade, wherein the sheet is in coiled form. Thereafter, uncoiling the sheet for straightening. Further, lifting the sheet and disposing over a first pallet in alignment with a laser cutting machine. Then cutting openings and blanks of predefined shape on the sheet and placing the sheet in a second pallet. At last, securing the reinforcement frames and panels to the sheet to form side wall of the railway coaches.

Brief description of the drawings

The advantages and features of the present invention will become better understood with reference to the following detailed description taken in conjunction with the accompanying drawings, wherein like elements are identified with like symbols/numerals, and in which:

Figure 1 shows the flow chart for the method of producing side walls of the railway coaches;

Figure 1a shows layout of Cold Roll Forming Machine to provide corrugation on sheet;

Figure 2 shows the layout of a laser machine system for producing side wall of the railway coaches;

Figure 3 shows side view of a spot welding machine;

Figure 3a shows another view of dual nuggets of the spot welding machine;

Figure 4 shows front view of the spot welding machine of figure 3;

Figure 5 shows a perspective view of a vacuum life; and

Figure 6 shows a sheet “X” of the present invention.

Detail description of the invention

For a thorough understanding of the present invention, reference is to be made to the following detailed description, in connection with the above-described drawings. Although the present invention is described in connection with exemplary embodiments, the present invention is not intended to be limited to the specific forms set forth herein. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but these are intended to cover the application or implementation without departing from the spirit of the present invention. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

The term “first”, “second” and the like, herein do not denote any order, elevation or importance, but rather are used to distinguish placement of one element over another, and the terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.

The present invention provides a method and system for producing side wall of railway coaches, which has better aesthetics without surface undulation. Further, the method and the system result in reduction in life cycle cost and require less maintenance. Moreover, the method and the system requires less time for production.

Referring now to figure 1, a flow chart of a method (100) for producing side wall of railway coaches in accordance with the present invention is illustrated. The method (100) starts at step (10). At step (20), selecting two meter or wider stainless steel coiled sheet “X” of 32101 duplex stainless steel having 2 meters width, has strength and is less prone to corrosion. In an embodiment, any other sheet of similar quality may be used for making side wall, which is obvious to a person skilled in the art. The coiled sheet “X” is than uncoiled and straightened into flat sheet “X” at step (30). Uncoiling of the sheet “X” is done by using a decoiler and straightener. At first the sheet is decoiled, by disposing the coil of the sheet “X” over a rod axially. The coil is then pulled to unwounded therefrom and then pressed on edges to straighten. Further, the sheet “X” cut into peaces of length of 20- 22 meters. Generally, the sheet has a width of about 2 meters, for the purpose of the present invention sheet having 2 meters of width is used for cut a single peace of 20-22 meter sheet. Once the sheet “X” is straighten it remains straight for further processing. This straightening method does not generate any undulation, thereby providing better aesthetics. It may be obvious to a person skilled in the art to used any other decoiling and straightening machine.

At step (40), the decoiled and straighten sheet “X” is passed though a cold roll forming machine to provide corrugation on the sheet “X” as shown in figure 1a to provide corrugation one the sheet “X” to improve aesthetics. This step may be added to produced side wall with corrugation. Step (40) can be eliminated to produce side wall with straight surface. The cold roll forming machine includes a decoiler 310, a roller leveler 312, a base 314 and a plurality of cold forming mills 316, the present invention is shown to include sixteen cold forming mills with desired projections to produce corrugation.

The uncoiled and formed sheet “X” is then lifted using a vacuum cups lift and placed on a first pallet (210) aligning with a laser cutting machine (215) as shown in figure 2 at step (50) as shown in figure 2. The first pallet (210) is a conjunction pallet. As shown in figure 5, the vacuum cups lift may include a plurality of vacuum cups, a plurality of vacuum cup holding members, at least on supporting member, a central member. Each of the vacuum cups is secured to all the ends of each of the vacuum cup holding member. All the vacuum cup holding member are placed horizontally and then the supporting member is disposed thereover and secured to the vacuum cup holding members. Further, a central member is secured centrally over the supporting member. The central member has an opening for allowing to pass a hook to secure there thorough, which can be then lifted by a crane or a hoist. The sheet “X” is secured by the vacuum cups, which are operated by a pneumatic pump. Upon securing the sheet “X” the lift is lifted by holding to the central member and placed at a desired position on the laser cutting machine. The total length of the lift may be about 20-22 meter, which enables to hold the sheet “X” properly and desired position on the laser cutting machine. Figure 6 shows the sheet “X” with openings cut using laser machine for forming windows “X1”

Further, the sheet is moved in the laser cutting machine (215) for cutting openings to from windows, doors and the like. Also, the laser cutting machine (215) cuts blanks for interlocking vertical & horizontal stiffeners, thereafter the sheet returns to the pallet (230) at step (60). In an embodiment, the laser cutting machine (215) is Computer Numerical Control, CNC, laser cutting machine. This machine can be preprogrammed to cut the sheet with desired openings. In the present invention, the laser cutting machine (215) is programmed to cut shapes of windows and doors. Further, the laser cutting machine (215) can be programmed to cut any other desired shapes, which is obvious to a person skilled in the art. In another embodiment, the laser cutting machine can be replaced by any other machine capable of cutting stainless steel and this is obvious to a person skilled in the art. At step (70), next uncoiled sheet is placed on the first pallet (210) for undergoing above cycle.

At step (80), reinforcement frames (260) are welded to the sheet with other panels to form a side wall of the railway coach. The welding is done by using spot welding machine as shown in figure 4. Spot welding is a process in which contacting metal surfaces are joined by the heat obtained from resistance to electric current. The sheet and the reinforcement frames (260) are held together under pressure exerted by electrodes. The process uses two copper alloy electrodes for spot weldinf. The electrodes are placed adjacent to each other instead of placing them opposite to each other with the sheet therebetween. Further, the sheet “X” is placed on a copper bed which is good conductor of heat of electricity. Further, a large current is passed though the electrodes which is carried thorough the copper bed and also pressure is applied on the sheet “X” by the electrodes to provide a good quality weld. The present machine can produce 14 spots per minute. The attractive feature of spot welding is that a lot of energy can be delivered to the spot in a very short time (approximately ten milliseconds), which permits the welding to occur without excessive heating of the remainder of the sheet.

The amount of heat (energy) delivered to the spot is determined by the resistance between the electrodes and the magnitude and duration of the current. The amount of energy is chosen to match the sheets material properties, its thickness, and type of electrodes. Applying too little energy wont melt the metal or will make a poor weld. Applying too much energy will melt too much metal, eject molten material, and make a hole rather than a weld. Another attractive feature of spot welding is that the energy delivered to the spot can be controlled to produce reliable welds.

As the side wall is made from a single sheet there is no undulation and welding marks, thereby providing better aesthetics. As the side wall is made from stainless still sheet, further painting can be eliminated. At step (90), the process ends.

Figures 3 & 4 shows various views of a welding assembly (200). A person skilled in the art may use other welding machine for the same purpose. The welding machine assembly (200) includes a CNC traveling gantry (240), a vacuum lift gantry rail (242), a spot welding machine (244), a stiffener (246) and a bed (248). The sheet is placed on the vacuum lift gantry rail (242). The vacuum lift gantry rail (242) guides the sheet to the welding machine (244). The laser cutting machine (215) cuts windows, doors and other panels out of sheet and then the sheet “X” is collected on copper bed. The welding machine (200) is used for welding sheet with the reinforcement frames (260) and other panels as shown in figure 3a. The vacuum lift gantry rail (242) enables to slide the sheets “X” one by one for welding. The spot welding machine (244) has at least one nugget for spot welding. The present invention is shown to use the spot welding machine (244) with dual nuggets. Further, the stiffeners (246) enable to secure the sheet “X” on the bed (248) for performing spot welding thereover. The CNC traveling gantry (240) is slidably disposed over the bed (248). The CNC traveling gantry (240) travels to the predefined portion for performing spot welding. As explained earlier, the sheet “X” is lead on the copper bed and two electrodes, which are placed adjacent to each other are used for welding.

By using the method (100) in one cycle, 2m x 1250x2 thick sheets for horizontal and vertical stiffeners and one sidewall sheet up-to 22m length is produced. The cycle is expected to take 180 to 260 min with 14 spots per minute including loading, unloading time, hence the productivity is high. Further, the method (100) of present invention enables use of Paint less sidewall and entails substantial saving in the life cycle cost.

Furthermore, the method (100) eliminate painting requirement thereby again saving cost and time. Moreover, use of stainless steel sheets reduces corrosion, thereby increases life of the side wall. The method 100) provides has better aesthetics without surface undulation to the side walls of the railway. The side walls of the railway prepared by suing the method (100) requires less maintenance with longer life and which is also eco friendly with lower life cycle cost. Also, the method (100) requires less time for production, which can match the acute shortage of railway coaches in India and enabling to eliminate rail coaches which have outlived and are prone to accidents. The method (100) does not require welding in-between, therefore maintains strength of the sheet “X”. as there are no welding joints the corrosion is reduced thereby increasing the life of the side wall.

The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention.
,CLAIMS:We Claim:

1. A method for producing side wall of railway coaches, the method comprising steps of:
selecting a sheet with predefined grade, wherein the sheet is in coiled form;
uncoiling the sheet for straightening;
lifting the sheet and disposing over a first pallet in alignment with a laser cutting machine;
cutting openings and blanks of predefined shape on the sheet and placing the sheet in a second pallet, and
securing the reinforcement frames and panels to the sheet to form side wall of the railway coaches.

2. The method as claimed in claim 1, after straightening the sheet is paased though cold roller for producing corrugation.

3. The method as claimed in claim 1, wherein the sheet is made of stainless steel.

4. The method as claimed in claim 1, wherein the opening having shape of a window and a door.

5. The method as claimed in claim 1, wherein the blanks are cut for interlocking vertical & horizontal stiffeners.

6. The method as claimed in claim 1, wherein the reinforcement frames and panels to the sheet by spot welding.

7. The method as claimed in claim 6, wherein the welding is done by computer numerical control CNC, spot welding machine.

8. The method as claimed in claim 1, wherein the first palate is a conjunction pallet.

9. The method as claimed in claim 1, wherein the sheet is lifted by a vacuum cups lift.

10. The method as claimed in claim 1, wherein the laser cutting machine is a Computer Numerical Control, CNC, laser cutting machine.