AN ARRANGEMENT FOR SEAM PREPARATION

Abstract: The unique in the construction is a number of important components and parts: a) the plate holder in molded aluminium; its double function and shaping in order to be able to be used as both a holder for plates and also serve for transfer of the circular movement to the linear, b) the driving wheel which facilitates the transfer of the circular movement to the plate holder, c) the superstructure which comprises a device for a press roll and also the parallel conveying bar and to make it possible for adjustment of the frictional pressure between the driving wheel and the plate holder, d) adjustment, through engine-driven gear racks, of the plasma gun for the making of holes.

Description: AN ARRANGEMENT FOR SEAM PREPARATION Introduction It is well known that school for welding and companies of today uses mechanical treatment (cutting-turning-milling-planing) for joint preparation of welding seams. The materials occurring at education for welding are stainless steel (alloyed), aluminium and black plate (unalloyed). The welding education can be carried out in such way that the trainee provides samples of plates and/alternatively on pipes/tubes. Seam preparation of plates may be carried out by means of applying the workpiece in a particular machine where use is made of oxygen/acetylene cutting. The method is expensive and time consuming. With respect to seam preparation of pipes/tubes, a number of problems occur. The method is very costly, time-consuming and comprises a number of hazardous operations. 1. The cutting of the pipe/tube are carried out in a band saw machine, alternatively by way of cutting wheel. 2. The pipe/tube are applied to a turning machine for the purpose of chamfer into a correct chamfer angle. These operations are hazardous with respect to an industrial safety point of view. The purpose with the present invention is that in a cost efficient way, and from a working-environment/safety point of view, securely prepare seams for plates as well as pipes/tubes. Description of the invention The purpose with the machine is to enable to carry out seam preparation for plates as well as pipes/tubes in the one and the same machine. The machine is cost saving, decreases/eliminates the risk for injuries and provides a high quality to the surfaces prepared. By way of using the combined construction of the machine, circular and linear movements, the stepless driving unit, and that in combination with a thermal cutting operation, these aims are fulfilled. The circular movement is achieved by means of an electric motor, running an angular gear which in its elongation (by way of a through shaft) transmits the movement to a work holding fixture assembled on a work drive dog. The circular movement is used for seam preparation of pipes/tubes. Thanks to the use of a work holding fixture, the seam preparation can be done down to a length of 50 mm (saving of material). The linear movement is achieved by way of a driving wheel applied on the work holding fixture. On the feeding ring and on a parallel conveying bar respectively, rests a plate holder. The moment between the feeding ring and the plate holder is adjusted by a rubber- covered press roll. The linear movement is used for seam preparation of plates. For the thermal cutting operation is use made of a plasma aggregate which manage to mix the protective gases argon, nitrogen and hydrogen in order to provide cuts without oxidation in for example stainless steel and aluminium. For unalloyed and low-alloy materials use is made of ordinary compressed air from existing plant. Gear racks, engine-driven, are applied on the machine in order to control the plasma gun vertically and the direction of the depth. Exhaust from the machine is done from two points: 1. Through a suction casing above the cutting area. 2. Through an outlet in the lower part of the machine. With this construction the machine has a shape with few movable parts which implies that the machine obtain a precision in the circular and in the linear movement. The movements can be adjusted stepless, when rotation speed of the driving unit has a working range of from 0.5 rpm up to 9 rpm. This results in an advancing speed for the plate holder in between the range 0.35 m/min up to 6.3 m/min, stepless adjustment. It has been shown in tests that the construction very well fulfils the great expectations/demands for precision and quality in connection with seam preparation.

Claims: Claims Device for linear and circular seam preparation. 1. The device for seam preparation is constructed in such a way that pipes/tubes and plates can be subjected to seam preparation in the same machine. A work holding fixture for circular workpieces is arranged in the driving device, and also the driving wheel which runs the plate holder resting on the parallel conveying bar for a linear movement for flat workpieces. 2. A device for control of the plasma gun in a motion to and fro, and also a movement vertically for making of holes in pipes/tubes. AMENDED CLAIMS [received by the International Bureau on 18 May 2000 (18.05.00); original claims 1 and 2 replaced by new claims 1-4 (1 page)] 1. A device for seam preparation of plates and pipes/tubes, in which device linear movements is provided for plates and circular movements is provided for pipes/tubes, characterised in that the device comprises a work holding fixture rotatable by an electric motor, to which work holding fixture pipes/tubes are intended to be arranged on for seam preparation, and the device further comprises a plate holder for rigid arrangement of a plate which is subjected to seam preparation. 2. Device for seam preparation according to claim 1, characterised in that the device further comprises a press roll arranged above said work holding fixture, whereby a linear movement is achieved by the work holding fixture which runs said plate holder, and also the press roll arranged against the plate holder and the work holding fixture. 3. Device for seam preparation according to claim 1 eller 2, characterised in that the movements providing the linear movement and circular movements is stepless. 4. Device for seam preparation according to any of the preceding claims, characterised in that the device for seam preparation comprises a plasma cutting aggregate.

Inventors: EDLUND KENT, EDLUND, KENT
Applicants: EDLUND KENT, EDLUND, KENT
Application year: 1999
Main classification: B23K10
IPC codes: B23K10, B23K33