GB2322586A

GB2322586A - Friction welding rails

Info

Publication number: GB2322586A
Application number: GB9804271A
Authority: GB
Inventors: Werner Prof Dr In Schwenzfeier
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-02-28
Filing date: 1998-02-27
Publication date: 1998-09-02
Also published as: ITMI980274A1; FR2760201A1; DE19807457A1; IT1298242B1; FR2760201B1; GB9804271D0

Abstract

Railway rails are friction welded by insertion of an intermediate piece 4 which is moved in linear or orbital oscillation between the rail ends. The two rail ends are pressed toward one another onto the intermediate piece 4 in the longitudinal direction of the rail in order to generate the heat, necessary for welding, through friction energy on both contact surfaces between each of the rail ends 7 and a respective surface of the intermediate piece 4.

Description

1 2322586 A MIETHOD AND APPARATUS FOR FRICTION WELDING RAILWAY RAILS The

invention relates to a method and an apparatus for friction welding railway rails and comparable, similar section beams.

Currently, there are essentially two welding methods which are used to seamlessly connect railway rails, i.e. thermit welding and electrical flash-butt welding.

Both methods have special advantages, but also deficiencies which are to be rendered avoidable by a new welding method.

Friction welding of axially symmetrical bodies is a method known for a long time, wherein the frictional heat, generated by the relative movement of two bodies which are pressed against one another with force, is used to sufficiently heat the volume parts to be welded. In the case of rotational friction welding machines, at least one of the two parts to be welded is rotated and, after sufficient heat build-up, pressed onto the counterpart to be welded, then the rotational motion is interrupted.

In the case of oscillatory welding machines, one of the two parts to be welded is moved oscillatingly relative to the counterpart while being pressed against it, until sufficient frictional heat for welding has been generated.

In this context, "oscillation" is meant to signify the periodic to-andfro motion of at least one of the two parts to be welded. If the path traversed during this is straight, the motion is called,linear oscillation". If the path is curved, for instance circular, elliptic or the like, the motion shall be called "orbital oscillation".

2 Since rails cannot be made to rotate in the track, only oscillation comes into question for friction welding rails.

The object of the present invention is to create a method of the specified kind in which friction welding can be used for connecting rails both in the production of long-welded rails as well as in the assembly thereof in the track.

This object is achieved, according to the invention, with a method of the specified kind in that an intermediate piece is moved in linear or orbital oscillation between the rail ends to be connected, while parallel thereto the two rail ends are pressed toward one another onto the intermediate piece in the longitudinal direction of the rail in order to generate the heat, necessary for welding, through friction energy on both contact surfaces between each of the rail ends and a respective cutting surface of the intermediate piece. owing to a method of this kind using an intermediate piece, it is possible in a particularly advantageous manner to achieve smaller heatinfluenced zones, shorter welding times and fewer welding failures. Furthermore, the structural expense for accomplishing the method according to the invention is advantageously reduced to a minimum.

Further advantageous developments of the invention become apparent from the sub-claims and the drawing.

The invention will be described in more detail below with reference to an embodiment represented in the drawing in which Fig. 1 shows a cross-section along the section lines A-A of an apparatus for oscillatory friction welding of rails, and Fig. 2 shows a plan view of the apparatus according to Fig. 1.

3 Two clamping devices 1, spaced from one another and connected to one another by means of tension rods 2 movable hydraulically parallel to the longitudinal direction of the rail, grip the rail ends 7 to be connected with one another and move them into the starting position, that is, at a distance "x" from one another. Into said clearance, located between the clamping devices 1, a fitting intermediate piece or form piece 4 (rail or section piece) having a length x-Ax is introduced and held by a gripping device 5 which is connected, on the one hand, form-fittingly to a vibration drive 3 and, on the other hand expediently at the free lower end spaced from the vibration drive 3 - via a preferably elastic guide system 6 to one or more guides. The vibration drive 3 is mounted on one of the two clamping devices 1. The guide system 6 is supported on a frame portion 9 which displaceably connects the two clamping devices 1 to one another.

The form piece 4 is adjusted to be in axial alignment between the rail ends 7 by means of adjusting means in the vibration drive 3 (which is preferably designed as a double excenter) and in the guide system 6. Subsequently, the (hydraulically operated) tension rods 2 pull the clamping devices 1, including the rail ends 7 to be welded, towards one another in the longitudinal direction thereof to make contact with the form piece 4. The vibration drive 3 is started and moves the gripping device 5, together with the form piece 4, between the rail ends 7 oscillatingly on orbital paths which are linear or curved, as desired. Frictional heat is generated on the contact surfaces between each rail end 7 and the form piece 4 when the tension rods 2 increase the pressing force.

The resulting frictional heat is determined by the friction factor, the pressing force and the entire vibration path, and in this way can be controlled to vary. After the temperature required for welding has been reached, the pressing force is increased quickly, the vibration motion is stopped and 4 the vibration drive 3 is moved to the null position in which the form piece 4 is positioned symmetrically with respect to a vertical plane of symmetry 10 of the rail. When a double excenter is used as a vibration drive 3, the null position can be achieved by adjusting the phase position of the two excenters with regard to one another. The numeral 8 denotes the two weld locations parallel to one another and spaced from one another in the longitudinal direction of the rail.

Claims

1. A method for friction welding railway rails and similar section beams, characterized in that an intermediate piece is moved in linear or orbital oscillation between the rail ends to be connected, while parallel thereto the two rail ends are pressed toward one another onto the intermediate piece in the longitudinal direction of the rail in order to generate the heat, necessary for welding, through friction energy on both contact surfaces between each of the rail ends and a respective cutting surface of the intermediate piece.

2. A method and apparatus according to claim 1, characterized in that the vibratory motion of the intermediate piece is preferably effected by means of a vibration drive designed as a double excenter by means of which, by adjusting the phase position of the two excenters with respect to one another, the null position of the intermediate piece is reached simultaneously with the stopping of the vibratory motion.

3. An apparatus for the method according to claim 1, characterized in that the gripping device for receiving the intermediate piece is, on the one hand, form-fittingly connected to the vibration drive and, on the other hand, guided along adjustable guides which are preferably elastic.

4. A method according to claim 1, substantially as herein described with reference to the accompanying drawings.

5. An apparatus for friction welding, substantially as herein before described with reference to figures 1 and 2 of the accompanying drawings.