Title of Invention

"DEVICE AND METHOD TO JOIN THE FACES OF PARTS"

Abstract The invention concerns a device and a method for axially aligned joining long parts, in particular rails, by friction welding. The invention provides, that the friction welding device (A) has clamping means (2,2") for the ends (11,11")of the parts and said clamping means can be adjusted relative one another and at least one clamping means can be moved relative to the opposite situated one, parallel to the sectioned plane(12, 12") of the part with diverging axes, as well as it can be positioned with the axes of the parts aligned and stationery. The method according to the invention is characterised in that the ends (11, 11") of the parts the cross-sectional surfaces (12, 12") to be joined are pressed against one another in a heating-up operation and at least one end of one part is moved relative to the opposite situated one with the axis deviating and in this manner the face regions are brought to an situated one with the axis deviating and in this manner the face regions are brought to an elevated temperature, followed by an axial alignment of the parts (1, 1") when their movements cease and the region of the weld is subjected to increased pressure for a full-surface metallic joining of the ends (11, 11") of the parts.
Full Text The invention concerns a device and a method to join the faces of very long parts by
friction welding. The invention particularly concerns a device and a method for axially
aligned joining of rails and the like by friction welding.
A joint by welding according to DIN 1910 is characterised in that the holding together of the parts is achieved by fusing the material using heat and/or force. The plane of separation between the workpieces is eliminated by metallically bonding their materials.
In the case of friction welding the surfaces of the workpieces or parts to be joined are moved relative one another under pressure and the regions of the surfaces are heated by friction, followed by a placing or pressing of the parts together resulting in metallic bonding.
In the majority of cases parts having rotationally symmetrical shape can be joined with one another by means of friction welding or fitted to workpieces, whereby at least one part rotates about its axis, therefore moves relative to the opposite situated one and is attached to another part or workpiece under pressure. By virtue of the factional heat released on the facing surfaces a heating up of the regions of the surfaces takes place to a temperature at which the part/material commences to soften. The actual welding takes place when the part(s) are stationary and the contact surfaces are strongly pressed together by a so called upsetting impact, thus producing a secure metallic joint of the materials.
l?riction welded joints and devices to produce them can be of great significance for particular materials and joints requiring little time for small or compact parts. However, in the case of long rods and the like a rotational movement to generate frictional heat in (lie joining regions is often possible only with the greatest effort and in many cases only theoretically.
A joining with aligned axes and aligned cross-sections using friction welding does not seem to be economical and cannot be produced with the required quality of the joint particularly in the case of long rods with a profiled cross-section like, for example, rails and beams.
From DE 198 07 457 Al a method to join rails by friction welding is known, whereby an intermediate piece is linearly or orbitally oscillating between the ends of the rails to be joined. At the same time the ends of both rails are pressed together in the longitudinal direction of the rails against the intermediate piece, thus generating the heat necessary for the welding by frictional energy on both contact surfaces between each rail end and each sectioned surface of the intermediate piece.
However, in the case of rail joints, produced in this elaborate manner, two weld transitions will result, increasing the possibly numerous weak positions. Furthermore, it is difficult to control the temperature management in the region of the joint during friction welding as well as to assure the equipment-related quality of the operation.
The object of the invention is to produce a device of the type mentioned in the introduction, with which long rods with profiled cross-section, like rails during the production of a track, can be joined with one another by friction welding, while an axial alignment and a cross-section conforming, high quality, metallic joining of the parts can be achieved.
A further object of the invention is to provide information about a generic method for the friction welding of rods, in particular of rails, with which a full-surfaced, homogeneous, cross-section conforming, metallic joining of the ends with high quality of the region of joint can be achieved.
According to the invention the objective is achieved with a generic equipment by that the friction welding device has clamping means for the ends of the parts and said clamping means can be adjusted relative one another and at least one clamping means can be moved relative to the opposite situated one, parallel to the sectioned plane of the part with diverging axes, as well as it can be positioned with the axes of the parts aligned and stationary.
The advantages achieved with the invention are basically to be seen in that the functions required for the friction welding of parts of high quality can be adjusted with accurate control. Thus cross-section conforming friction welded joints of rails, for example, can be produced, while merely an easily removable lateral bead of small dimensions is formed in the region of the weld.
When, as it can be provided by the invention, at least one clamping means can gyrate around the axis of the joint, a favourable homogeneous heating up of the ends of the parts over the entire region of the cross-section can be carried out.
In a configuration of the invention it is an advantage when both clamping means can gyrate in the same direction each at an opposing distance from the axis of the joint and around same. This embodiment of the device makes possible on the one hand a homogeneous heating up of the intended region of the joint of the parts by friction with movements that are technologically favourable and as far as possible vibration-free, and on the other hand an immediate stationary axially aligned positioning of the ends of the parts for the actual joining operation is advantageously possible by virtue of ceasing the deflection.
To achieve an as vibration-free as possible and the possibility of an adjustment of the parts to be welded within a short time, eccentric means, that can be driven and the deviation of which relative the axis of rotation is adjustable, are provided to move and keep stationary the clamping means in an axially aligned position.
In conjunction with the progress of the movement a particular advantage is achieved when for each clamping means two drivable eccentric means are provided functionally connected with the clamping means.
In a configuration, whereby the opposite situated clamping means can be driven or adjusted to be stationary by adjustable eccentric means positioned on a shaft, while preferably an opposite directed deviation from the axis of rotation and an axial alignment of the ends of the parts is provided in particular by a simultaneously acting control of the eccentric means, the device according to the invention has not only advantages as far as control techniques are concerned, but makes a favourable construction as far as economics and process technology are concerned.
A further aim of the invention in the case of a method of the type mentioned above is achieved by that the ends of the parts have flat cross-sectional surfaces at right angle to the axis and following this the cross-sectional surfaces to be joined are pressed against one another in a heating-up operation and at least one end of one part is moved relative to the opposite situated one with the axis deviating and in this manner the face regions are brought to an elevated temperature or joining temperature, followed by an axial
alignment of the parts when their movements cease and the region of the weld is subjected to increased pressure for a full-surface metallic joining of the ends of the
parts.
The advantages of a welding process carried out in this manner are mainly that the friction movement is carried out without rotating the parts and therefore no high inertia forces will occur when their movements change. At the same time at least one end of one part is moved under pressure in an oscillating manner in a direction lying in the plane of the cross-section relative to the one situated opposite. After reaching the joining parameters on the friction surfaces, to cease the movement of the ends only slight forces are required to carry out their cross-section conforming positioning. If for the purpose of frictional heating-up in a favourable manner one end of one part is moved in the plane of the cross-section while the region of the end undergoes a flexible deflection, then restoring forces lead to or at least help to establish an axial alignment of the parts for the upsetting impact, whereby a single high quality metallic joint can be achieved in this manner.
For an as far as possible vibration-free progress of the movement it has proved itself advantageous, when for the increase of the temperature or for the setting of the joining temperature of the regions of the faces of the parts at least one end of one part carries out a gyrating movement.
When in a particularly preferred embodiment of the invention to increase the temperature of the region of the faces of the parts, the ends of the parts are moved gyrating in the same direction at a distance from the axis of alignment or of the joint while subjected to pressure, very effective full-surface good welded joints can be produced and the movements of the regions of the ends of the parts can be reduced by further reducing the vibrations in the system. Consequently the expenditures connected with the method to cease the movement of the ends of the parts are also reduced.
For an axial alignment of parts with particular cross-sections in a joining process followed by a welding of high quality, it could be advantageous when after pressing together the cross-sectional surfaces and an axially deviating movement of the ends of the parts for their heating up the pressure is reduced, an axial alignment of the parts is earned out and following this the pressure for the metallic joining of same is increased.
When establishing a joint friction welding, parts like rails from hardenable steels and alloys can have in the weld seam and/or in the heat-influenced zone, regions with unfavourable, brittle microstructure. This structure, for example a martensite structure, is formed when during welding the material becomes austenitic, i.e. it is transformed into a cubic face-centred atomic structure and after joining the parts the speed of cooling, in particular the dissipation of the heat into the part is so great, that the transformation of the texture is carried out suddenly without any diffusion. According to the invention this disadvantage can be overcome by that prior to the heating up process a preheating of the face regions of the ends of the parts is carried out.
A preheating of the regions of the faces of the ends of the parts can be particularly advantageously carried out by moving them relative one another with a reduced pressure, while at the same time the welding equipment is used in a favourable manner for the heating of the ends of the parts and an oxidation of the welded surfaces can be prevented.
Accordingly, there is provided a device for joining the faces of very long parts defining longitudinal axes, in particular rods with a profiled cross-section like rails and the like, by friction welding, characterized in that the device includes clamping means for clamping the ends of the parts and in that said clamping means can be adjusted relative to one another and wherein at least one clamping means can be moved relative to the opposite situated clamping means, in a direction generally parallel to the end face of the part with the longitudinal axes of the parts moving away from one another, as well as being positionable with the axes of the parts aligned and stationary.
The invention is explained in detail in the following based on a drawing illustrating an embodiment.
The single figure shows schematically a friction welding equipment A.
Clamping means 2,2" are provided for the parts 1, 1" to be joined, the clamping means detachably connected with the ends 11, 11" of the parts via gripping parts 21, 21". Each clamping means 2, 2" is functionally connected at least with one adjustable eccentric means 3, 3", that can be driven by a shaft 41 via a motor 4 or the like, while the eccentricity of the eccentric means 3, 3" can be adjusted by a control 31, 31".
When the eccentric means 3, 3" are rotatably driven by a motor 4 via a shaft 41 and via the control means 31, 31", their eccentricities are set in different directions, in particular opposing one another, uneven, in particular opposite directed oscillations of the respective eccentric surfaces will take place in the direction of the parts 11, 11" to be welded. The eccentric means 3, 3" are, however, functionally connected via the bearing 5, 5" with the clamping means 2, 2", so that they, are consequently the clamped-in ends 11, 1 l"of the parts, will move relative one another. A further mounting (not illustrated) of the clamping means 2, 2" may be carried out by movable bearings or possibly also by eccentric means driven at the same angular velocity.
When the friction welding process is being carried out, the parts 1, 1" to be joined with their ends 11, 11" are clamped, via the clamping parts 21,21", in the clamping means 2, 2", with their cross-sectional surfaces 12, 12" being at right angles to the axis, and pressed against one another with a force and counterforce, respectively, of+xl, -xl. As a result of the pressing force a relative or frictional movement is carried out between the opposite situated ends 11, 11" of the parts by an uneven axis-deflecting movement of the clamping means 2, 2". Such a relative movement of the clamping means 2, 2" is caused by an uneven setting of the eccentricity of the eccentric means 3, 3", functionally connected with them, and driven on the shaft 41 by a motor 4.
A relative movement of the cross-sectional surfaces 12, 12", when pressed against one another, release frictional heat that heats the regions of the cross-sectional surfaces to a joining temperature. Immediately after reaching such a temperature and simultaneously the eccentricity of the eccentric means 3,3" ts cancelled via the control 31, 31", and consequently an axially aligned movement of the ends of the parts ceases with a subsequently acting pressure of+x2, -x2 on the cross-sectional surfaces 12, 12".
Alter cooling off the welded zones of the parts, possibly with a reduced cooling speed, affected by pre-heating the ends 11, 11" of the parts, to set particular properties in this region, the squeezed out material caused by a final application of pressure or an upsetting impact can be mechanically removed thus establishing a joint with conforming sections.







WE CLAIM:
1. A device for joining the faces of very long parts defining longitudinal axes, in particular rods with a profiled cross-section like rails and the like, by friction welding, characterized in that the device includes clamping means (2.2) for clamping the ends of the parts and in that said clamping means can be adjusted relative to one another and wherein at least one clamping means can be moved relative to the opposite situated clamping means, in a direction substantially parallel to the end face of the part with the longitudinal axes of the parts moving away from one another, as well as being positionable with the axes of the parts aligned and stationary.
2. A device as claimed in claim 1, wherein at least one clamping means gyrates around the axis of the joint.
3. A device as claimed in claim 1 or 2, wherein both clamping means gyrate in the same direction each at an opposing distance from the axis of the joint and around same.
4. A device as claimed in any one of claims 1 to 3, wherein eccentric means, (3,3) that is driven and the deviation of which relative the axis of rotation is adjustable, are provided to move and keep stationary the clamping means in an axially aligned position.
5. A device as claimed in any one of claims 1 to 4, wherein each clamping means has two drivable eccentric means functionally connected with them.
6. A device as claimed in any one of claims 1 to 5 wherein the opposite situated clamping means can be driven or adjusted to be stationary by adjustable eccentric means positioned on a shaft, while preferably an opposite directed deviation from the axis of rotation and an axial alignment of the ends of the parts is provided in particular by a simultaneously acting control of the eccentric means.
7. A method for joining very long parts, in particular rods with a profiled cross-section like rails and the like, by friction welding, an a claimed as claims in claim1 in which the ends of the parts have flat cross-sectional surfaces at right angles to their longitudinal axes and wherein the cross-sectional surfaces to be joined are pressed against one another in a heating-up operation and at least one end of one part is moved relative to the opposite situated one with the longitudinal axes moving out of alignment with one another and in this manner the face regions are brought to an elevated temperature or joining temperature, followed by an axial alignment of the parts when their movements cease and the region of the weld is subjected to increased pressure for a full-surface metallic joining of the ends of the parts.
8. A method as claimed in claim 7, wherein to increase the temperature or to set the joining temperature of the regions of the faces of the parts at least one end of one part carries out a gyrating movement.
9. A method as claimed in claims 7 or 8 wherein to increase the temperature of the region of the faces of the parts, the ends of the parts are moved gyrating in the same direction at a distance from the axis of alignment or of the joint.
10. A method as claimed in any one of claims 7 to 9, wherein after pressing together the cross-sectional surfaces and an axially deviating movement of the ends of the parts for their heating up the pressure is reduced, an axial alignment of the parts is carried out and following this the pressure for the metallic joining of same is increased.
11. A method as claimed in any one of claims 7 to 10, wherein prior to the heating up process a preheating of the face regions of the ends of the parts is carried out.
12. A method as claimed in claim 11, wherein a preheating of the regions of the faces of the ends of the parts is carried out by moving them relative one another with a reduced pressure.
13. A device for joining the faces of very long parts substantially as hereinbefore described with reference to the accompanying drawings.

Documents:

505-del-2004-abstract.pdf

505-del-2004-claims cancelled.pdf

505-DEL-2004-Claims.pdf

505-del-2004-complete specification (granted).pdf

505-del-2004-correspondence-others.pdf

505-del-2004-correspondence-po..pdf

505-del-2004-description (complete).pdf

505-del-2004-drawings.pdf

505-del-2004-form-1.pdf

505-del-2004-form-19.pdf

505-del-2004-form-2.pdf

505-del-2004-form-3.pdf

505-del-2004-form-5.pdf

505-del-2004-gpa.pdf


Patent Number 217820
Indian Patent Application Number 505/DEL/2004
PG Journal Number 17/2008
Publication Date 25-Apr-2008
Grant Date 28-Mar-2008
Date of Filing 18-Mar-2004
Name of Patentee VOESTALPINE SCHIENEN GmbH
Applicant Address Kerpelystrasse 199, A-8700 Leoben, AUSTRIA.
Inventors:
# Inventor's Name Inventor's Address
1 HANS PFEILER Turmgasse 3I, A-8700 Leoben, AUSTRIA.
PCT International Classification Number B23K 20/12
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 A 455/2003 2003-03-21 Austria