METHOD AND DEVICE FOR FRICTION WELDING

• US 3,732,613 A
• Filed: 12/17/1970
• Issued: 05/15/1973
• Est. Priority Date: 12/18/1969
• Status: Expired due to Term

• Current Assignee: Messer Griesheim GmbH
• Original Assignee: Karl-Heinz Steigerwald
• Inventors: Steigerwald, Karl-Heinz
• Primary Examiner(s): Overholser, J. Spencer
• Assistant Examiner(s): Craig, Robert J.
• Application Number:
  US05/098,528
• Time in Patent Office: 880 Days
• Field of Search: 228/2 29/470.3 156/73
• US Class Current: 228/112.1
• CPC Class Codes: B23K 20/1205 using translation movement

Abstract

The method of friction welding is applicable to surfaces to be welded with any type of marginal boundary. Two workpieces to be welded together are arranged against each other at the surfaces to be welded and are heated to welding temperature by a relative oscillatory movement along such surfaces. The relative oscillatory movement is effected by way of relative rotatory movement with the workpieces remaining substantially parallel to each other. A device for carrying out the method comprises a workpiece holder driven by an eccentric body rotatable about an axis. A circular rotatory path is defined on the body and the eccentricity of this path is adjustable relatively to said axis, the holder being movable at least two-dimensionally in a plane corresponding to the orientation of the surface to be welded. The holder is guided on the path of progression of the eccentric body so that, upon rotation of that body, all parts of the holder perform rotatory movements of equal size and circular shape with a radius equal to the adjusted eccentricity of the eccentric body.

Claims

1. A method for frictionally welding together the abutting surfaces of two workpieces to be welded together which comprises holding said surfaces together under pressure and substantially parallel to each other, producing substantially equal circular relative orbital movement between all points of said surfaces while restraining said surfaces against rotation, whereby said surfaces are frictionally heated to welding temperature, the amplitude of said orbital movement being determined by the radius of said orbital movement, and adjusting the amplitude of said relative orbital movement by altering the radius thereof during the welding process in accordance with conditions prevailing within the friction area.

2. A method according to claim 1, wherein, at the commencement of the welding operation, the amplitude of the relative orbital movement is increased from zero upwards.

3. A method according to claim 1, wherein, towards the termination of the welding operation, the amplitude of the orbital movement is decreased towards zero.

4. A method according to claim 1, wherein the contact pressure applied to the abutting surfaces and the frequency of the orbital movement, are altered during the welding process depending on conditions prevailing in the friction area.

5. A method according to claim 1, wherein the frequency and amplitude of the orbital movement are altered in dependence on each other, preferably in opposite senses in such a way that the relative velocity of motion of the workpieces is maintained within a prescribed range, and preferably remains approximately constant.

6. A method according to claim 4, wherein said alteration is made in dependence upon the size of the friction surface.

7. A device for frictionally welding together the abutting surfaces of two workpieces comprising means for mounting at least one of said workpieces on a holder, means for holding said abutting surfaces together under pressure, means including an eccentric body mounted for circular orbital movement about an axis perpendicular to said surface to produce substantially equal circular relative orbital movement between all points of said abutting surfaces, and including means for restraining said workpiece holder and said workpiece against rotation, and means for adjusting the eccentricity of said body relatively to said axis during the said orbital movement.

8. A device according to claim 7, wherein, to adjust the resultant eccentricity (Er), the eccentric body with the orbital path located relatively thereto is shiftable relatively to the axis of rotation.

9. A device according to claim 7, wherein, to adjust the resultant eccentricity (Er) of the eccenTric body, a hub unit incapable of displacement relatively to the axis of rotation is provided, to which unit the eccentric body is attached in an adjustable manner.

10. A device according to claim 7, wherein on the eccentric body there is defined a second circular path the axis of which lies with a fixed eccentricity parallel to the axis of the first orbital path, and in that a second eccentric body is provided on which a third circular path is defined which matches the second circular path, is led along it and is situated, with invariable eccentricity, parallel as regards its axis to the axis of rotation, and in that a coupling device is provided which rigidly couples the two eccentric bodies but is capable of adjustment to various mutual angular positions of such bodies, so that the resultant eccentricity (Er) of the first circular path that is dependent on the mutual angular position of the eccentric bodies is continuously adjustable with reference to the axis of rotation.

11. A device according to claim 10, wherein the eccentricity of the first circular path in relation to the second orbital path is equal to the eccentricity of the third orbital path in relation to the axis of rotation.

12. A device according to claim 10, wherein the coupling device has a control element rotatable about the axis of rotation, the element being adjustable as regards its angular position relative to the second eccentric body and being coupled for common rotation with the first eccentric body in the direction of the periphery.

13. A device according to claim 12, wherein the rotary connection between the control element and the first eccentric body has a slot-type guidance system extending in the radial direction and a finger which engages thereinto.

14. A device according to claim 12, wherein the control element has a sleeve or enclosing ring which is rotatable but axially located on a hollow shaft firmly connected to the second eccentric body and coaxial with the axis of rotation, in the sleeve and in the shaft there being slots provided in the same axial zone, these crossing diagonally of the axial direction, and in the hollow space in the shaft there is an axially displaceable rod on which is fastened a pin which passes through both slots and fills the width of the slots.

15. A device according to claim 7, wherein the holder for the workpiece is linked by way of parallelogram-type linkage to a carriage displaceable normally of the axis of rotation.

16. A device according to claim 7, wherein a mass balancing device is adjustable in dependence on the resultant eccentricity (Er) adjusted for at a given moment, in such manner that the resulting imbalance in relation to the axis of rotation is substantially compensated for as regards all adjustable values of the resultant eccentricity.

17. A device according to claim 10, wherein to the two eccentric bodies there is in each case rigidly connected a compensatory weight arranged at a prescribed distance from the axis, in each pair provided by one of said eccentric bodies and a corresponding compensatory weight the centers of gravity of the eccentric body and of the compensatory weight being in the same axial planes but on contrary sides of the axis, and wherein the magnitudes of the two compensatory weights are determined by the fact that, given two differing resultant eccentricities, the device is compensated for mass imbalance, for example with the resultant eccentricity at zero and also with the resultant eccentricity at its maximum.

18. A device according to claim 17, wherein the compensatory weights are exchangeable.

19. A device according to claim 17, wherein the compensatory weights are axially and/or radially displaceable, the axial adjustability more particularly serving to adjust the axial position of the centers of gravity of the compensatory weights in accordance with the character of the workpiece mounted on the holder.

20. A device according to claim 7, wherein means are provided tO alter the rate of rotation of the eccentric body.

21. A device according to claim 7, wherein means are provided for the prescribable linkage together of alterations in the resultant eccentricity with alterations in the rate of rotation of the eccentric body.

22. A device according to claim 7, wherein means are provided for exerting pressure on the workpieces perpendicular to the surfaces to be welded.

23. A device according to claim 17, wherein the compensatory weights are radially displaceable.

24. A device according to claim 14, including a compensatory weight rigidly connected to each of said eccentric bodies and arranged at a prescribed distance from the axis, the center of gravity of each eccentric body and its compensatory weight being in the same axial plane but on opposite sides of the axis, the magnitudes of the two compensatory weights being such that the device is compensated for mass imbalance for differing resultant eccentricities.