This application is a continuation-in-part of pending International Application No. PCT/IN2021/051109 filed Nov. 27, 2021, which claims priority to Indian Patent Application No. 202031053044 filed Dec. 5, 2020 and hereby incorporates both applications by reference in their entireties.
The present invention relates to a forging machine for progressive hot end-forging of asymmetric to symmetric rail and a process of hot end-forging of asymmetric to symmetric rail.
Forging is a method of deforming steel in a heated condition to a predetermined shape using a hammering or pressing method. Hydraulic pressing systems can be categorized generally as either (a) open die or (b) close die. In open die systems, a heated metal blank is pressed between two steel plates or die. Normally, a bottom platen is fixed and the top platen is movable. Pressing is done by means of a double acting hydraulic cylinder. In closed die forging, the heated metal blank is placed in a die resembling a mold, which confines the metal work piece to the die and causes it to take on the shape of the die.
The state of the art is to heat a rail in a heater and conduct three consecutive forging operations as shown in
In order to make the process faster, cost effective, and to decrease rejection rate, embodiments of the present invention provide a combination of hydraulic presses and an unique press configuration for end-forging of asymmetric rail to symmetric rail, as well as a novel end-forging manufacturing process. Symmetric rail is regularly used by Railway Authorities.
The present invention provides an asymmetric to symmetric rail forging press, comprising: a roller table (209) having one translational axis, the roller table being adapted to receive a railroad rail (210) and translate a railroad rail fore and aft along the one translational axis; an induction heater (208) adapted to receive an end portion of a railroad rail, the induction heater being laterally movable between a working position in line with a railroad rail, and a home position not in line with the railroad rail; a first forging station in line with the roller table (209) and adapted to receive a railroad rail therefrom, the first forging station comprising a first pair of opposing horizontal hydraulic cylinders (206a, 206b) having horizontal strokes and driving a first set of horizontal forging dies (219), and a first top hydraulic cylinder (211) having a vertical stroke, the first top hydraulic cylinder being aligned to vertically impinge on the first set of horizontal forging dies during a horizontal forging operation, and the first forging station further including two clamps spaced apart along the length of a railroad rail and adapted to fix the position of a railroad rail during a forging operation; a second forging station in line with the roller table (209) and adapted to receive a railroad rail from the first forging station, the second forging station comprising, a second pair of opposing horizontal hydraulic cylinders (207a, 207b) having horizontal strokes and driving a second set of horizontal forging dies (218), and a second top hydraulic cylinder (201) having a vertical stroke and driving a top die (323), and the second forging station further including a clamp adapted to receive an end of a railroad rail and fix the position of a railroad rail during a forging operation; and the top die (323) being linearly translatable between two working positions corresponding to a first portion (323a) of the top die and a second portion (323b) of the top die, wherein the first portion (323a) of the top die includes a lateral step (423) running the length of the first portion (323a), and wherein the second portion (323b) of the top die is flat, omitting the lateral step (423).
The invention further provides a process for asymmetric to symmetric rail forging comprising the steps of: mounting a rail to a roller table in line with a first forging station, the roller table being adapted to drive the rail along one translational axis; positioning an induction heater between the roller table and the first forging station; driving the rail into inductive communication with the induction heater; inductively heating the rail to a predetermined forging temperature; driving the rail to a first forging station; clamping the rail at ends of a working section of the rail; pressing a first set of horizontal forging dies into a head portion of the rail and into a first section of the web portion of the rail; translationally driving a set of add-on dies to a position stacked vertically on the first set of horizontal dies; pressing the first set of horizontal forging dies and the add-on dies into the head portion of the rail, the first section of the web portion of the rail, and a second section of the web portion of the rail; driving the rail to a second forging station; clamping the rail at three points including an end of the rail, a middle portion of the rail and an unworked portion of the rail; pressing a second set of horizontal forging dies into the head portion and the web portion; pressing a first portion of a top die, from a first position, into a foot of the rail; translationally driving the top die from the first position to a second position; and pressing a second portion of the top die into the foot of the rail.
Other benefits and advantages will become apparent to those skilled in the art to which it pertains upon reading and understanding of the following detailed specification.
The invention may take physical form in certain parts and arrangement of parts, embodiments of which will be described in detail in this specification and illustrated in the accompanying drawings which form a part hereof, wherein like reference numerals indicate like structure, and wherein:
As used herein the terms “embodiment”, “embodiments”, “some embodiments”, “other embodiments” and so on are not exclusive of one another. Except where there is an explicit statement to the contrary, all descriptions of the features and elements of the various embodiments disclosed herein may be combined in all operable combinations thereof.
Language used herein to describe process steps may include words such as “then” which suggest an order of operations; however, one skilled in the art will appreciate that the use of such terms is often a matter of convenience and does not necessarily limit the process being described to a particular order of steps.
Conjunctions and combinations of conjunctions (e.g. “and/or”) are used herein when reciting elements and characteristics of embodiments; however, unless specifically stated to the contrary or required by context, “and”, “or” and “and/or” are interchangeable and do not necessarily require every element of a list or only one element of a list to the exclusion of others.
Terms of degree, terms of approximation, and/or subjective terms may be used herein to describe certain features or elements of the invention. In each case sufficient disclosure is provided to inform the person having ordinary skill in the art in accordance with the written description requirement and the definiteness requirement of 35 U.S.C. 112.
One embodiment of the present invention is a forge configured for hot end-forging asymmetric rail to symmetric rail.
Some embodiments include a two forging positions and an in-line heater arranged such that a rail moves from the heater to the first forging position, and then to the second forging position along the same line. Such embodiments eliminate the need for manipulators to reorient the rail. As shown in
With continuing reference to
With regard to the second top hydraulic cylinder 201,
In another embodiment, the die is closed providing forging forces acting on all the surfaces of the rail simultaneously, and resulting in a dimensionally accurate product.
In another embodiment, pre-cutting an end portion of a rail through the foot and partway through the web provides structure suitable for receiving a clamp 215, which leads to improved straightness of the rail after forging.
In another embodiment, the induction heater 208 and the first and second forging stations are arranged such that a rail 210 can be shifted in a line along the length of the rail 210 from the heater 208 to each station. The first forging station comprises horizontal hydraulic cylinders 206a, 206b, and vertical cylinder 211. The second station comprises horizontal cylinders 207a and 207b, and vertical cylinder 201. After carrying out a first forging operation at a the first station, vertical cylinder 211 impinges the horizontal die or die housing driven by horizontal cylinders 206a, 206b to disengage the die from the work piece, thus preventing lap formation. Then the partly forged rail 210 is shifted to the second forging station to carry out the next forging operation. The partially forged rails remain in this second location for subsequent forging operations on the rail foot involving the top cylinder 201 and a linearly translatable top die 323. Unlike the first station, the second forging station includes a top die 323 that is linearly translatable along an axis in line with the rail 210. This allows different portions of the top die to engage a work piece by translating the top die along a linear axis.
With reference to
Turning to
In contrast to the first forging station, which consist of a pair of side cylinders, 206a and 206b, and a top cylinder 211 having only a vertical axis of motion (
In another embodiment an induction heater 208 for heating the rail 210 is mounted on a laterally movable stand 212, which for example and without limitation, may be hydraulically operated. The rail 210 is advanced fore and aft along a single translational axis using a servo motor-driven roller table 209 fitted with proximity switches for accurate linear positioning of the rail 210. The induction heater 208 can be moved inline between the rail 210 and the first and second forge stations when heating is required, and moved away when heating is complete. The rail 210 can be accurately driven forward by the servo table 209 into the induction heater 208 to a predetermined location. After reaching required temperature the rail 210 can be driven aft by the roller table 209, withdrawing it from the induction heater 208. The induction heater 208 can then be laterally driven back to its home position. The rail 210 is again driven forward by the roller table 209, accurately positioning it inside the forge without the need for rotating the rail 210, or moving the rail 210 in any direction other than fore and aft.
A process according to an embodiment of the invention comprises the following steps. A 20 mm wide slot 1002 is cut 80 mm from one end of a rail to a height of 80 mm from the rail foot 1016 as shown in
The process further includes the step of mounting the rail 210 to a movable servo-motor-controlled roller table 209 in an inverted orientation, with the head facing down (see e.g.
The process further includes the induction heater 208 being moved to a position in-line between the rail 210 and the forge. The roller table 209 drives the rail 210 forward to a predetermined position corresponding to the interior of the induction heater 208, and the rail 210 is held in this position until a temperature reading indicates that the rail 210 is properly heated for forging, typically about 1180° C. The roller table 209 then withdraws the rail 210, for example to the home position, and the induction heater is moved from between the rail 210 and the forge.
The process further includes the roller table 209 driving the rail forward to a second predetermined position corresponding to the first forging station. Clamps 13 and 14 are applied to the rail 210 being forged thereby preventing lateral bending of the rail 210. With reference to
In
In an optional intermediate step, the rail 210 may be reheated by withdrawing it using the roller table 209, and moving the induction heater 208 back to the inline position. The roller table 209 then drives the rail 210 back into the induction heater 208, compensating for dissipated heat and bringing the rail back up to a forging temperature i.e., about 1150° C. The roller table then withdraws the rail 210 from the heater 208 and the heater is laterally moved back to its home position.
The rail 210 is advanced by the roller table 209 to the second forging station and clamped at three points with clamps 213, 214, and 215. With reference to
According to one embodiment the asymmetric rail forging press operations are controlled by a programmable logic controller having suitable safety interlocks. The forging process is operated through control desk equipped with a Supervisory Control and Data Acquisition (SCADA) system. Ample visualization and instrument data are displayed on the Human Machine Interface (HMI) screen.
According to one embodiment, a roller table 209 is adapted to receive a railroad rail 210, or similar work piece, and linearly position the rail along an axis. According to one embodiment, the rail may be inverted with the foot facing up and the head facing down; however, the invention is not limited to orientation. The roller table 209 is driven by a suitable means such as, without limitation, a servomotor. A starting position of the rail 210 may be considered a “home” position, as illustrated in
The rail is then driven to a first forging station 1101, as shown in
The first station 1101 also includes two clamps 213, 214 for holding the rail 210 during the forging operations. Suitable clamps are illustrated in
The first horizontal forging dies 219 are shaped to form a closed die having the shape of the head 1018 and a portion of the web 1017 of a symmetric rail. When the die 219 is closed, i.e. pressed into the rail, the head 1018 is converted from asymmetric to symmetric and a portion of the web 1017 is thinned, increasing the height of the web. The balance of the web 1017, and the foot 1016, require further forging, which is handled in the next forging operation.
Regarding the next forging operation, add-on dies 722 are translationally driven along axis A (
With continuing reference to
With combined reference to
The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description only, they these are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously modifications remain possible, in particular from the point of view of the design of the various elements or by substitution of equivalent methods, without thus departing from the scope of protection of the invention.
Number | Name | Date | Kind |
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4192172 | Mersek | Mar 1980 | A |
4291566 | Dinsdale | Sep 1981 | A |
4907436 | Korytko | Mar 1990 | A |
5272896 | Mine | Dec 1993 | A |
20150013421 | Choda | Jan 2015 | A1 |
Number | Date | Country |
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104550593 | Jan 2017 | CN |
107142367 | Jan 2017 | CN |
Number | Date | Country | |
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20230166309 A1 | Jun 2023 | US |