GB2035873A

GB2035873A - Apparatus for rotatably supporting a cylindrical hollow body

Info

Publication number: GB2035873A
Application number: GB7939905A
Authority: GB
Original assignee: Blohm and Voss GmbH
Current assignee: Blohm and Voss GmbH
Priority date: 1978-11-23
Filing date: 1979-11-19
Publication date: 1980-06-25
Also published as: SE7909720L; CA1137742A; GB2035873B; FR2442101A1; JPS5573472A; JPS5827025B2; DE2850721B2; SE436846B; FR2442101B1; IT7927443A0; IT1126351B; DE2850721C3; DE2850721A1

Abstract

The apparatus has supporting discs 9 arranged to centrally support each end of the cylinder 10 and supporting members 7 which are radially adjustable with respect to the hollow body. The supporting discs 9 are connected to journals 6 which each rest upon supporting rollers 8 of a roller block 5 and the hollow body is rotated by a motor 2 acting upon one of the journals 6 through the intermediary of a thrust bearing 3. Axial expansion of the hollow body during welding is permitted by axial movement of the roller block remote from the motor 2. The appts can be used to support a cylinder as the wall thickness is increased using reciprocally mounted welding heads 19. <IMAGE>

Description

SPECIFICATION Apparatus for rotatably supporting a cylindrical hollow body about an axis thereof The invention relates to an apparatus for rotatably supporting a cylindrical hollow body about an axis thereof, the hollow body being of extreme wall thickness (e.g., in excess of 400mm) and substantial length (e.g., 10,000 mm), such as are used for example for jet engine construction. As is known, the production of such bodies consisting of high grade steel is restricted inasmuch as, for obvious reasons, rolling installations are normally unable to process an overdimensioned wall thickness of 400 mm wall or greater.

The present invention seeks to permit the production of such tubular hollow bodies whilst largely dispensing with a shaping device.

According to this invention there is provided an apparatus for rotatably supporting a cylindrical hollow body about an axis thereof, the wall thickness of which is to be increased by application of a weld, said apparatus comprising supporting discs arranged to centrically support each end of the hollow body, supporting members which are radially adjustable with respect to the hollow body, the supporting discs being connected to journals which journals each rest upon supporting rollers of a roller block.

To provide a background for the invention, a cylindrical basic body of relatively small wall thickness is prefabricated and the latter is then increased by application of a weld on the basic body which body is made of a high grade steel sheet of small thickness. The weld is formed by a plurality of helicoidally oriented weld beads fused together.

It has been discovered that such weld satisfies metallurgically high standards of loadbearing capacity, particularly if, the helicoidally oriented weld beads are generated on the axially rotating basic body by a powder shielded welding process.

In order to reduce as far as possible the production time of a hollow body produced by the aforedescribed method, it is.proposed that the weld beads are produced by a plurality of horizontally, synchronously drivable, portable and vertically adjustably arranged welding units.

An apparatus for performing the method consists in the welding device being constituted by a plurality of welding heads drivable synchronously e.g., by a traction chain, with each of which a supply carriage is associated.

The welding heads are vertically, adjustably mounted in adaptation to the growing application weld.

The supply carriages associated with the welding heads serve to accommodate the welding rod, e.g., present on one or more reels, and the welding powder.

In order to ensure that a continuous and hence rational work procedure can be achieved in relation to the application welding, both the welding heads and the supply carriages are mounted transportably or slidably and portably in platforms. The respective supply carriage constitutes an entity with the associated welding head, which is portable e.g., by means of a crane so that the entity when it has attained its limit position can be returned into the initial position in order to participate afresh in the application welding.

This measure dictates that the platforms are vertically adjustably e.g., by spindles or a hydraulic system, in adaptation to the relevant basic body.

In order to form the application weld desired according to the invention and comprising a plurality of spiral-shaped weld beads, a drive device mounted on a bracket and constituted by a motor and thrust bearing is provided, which co-operates with the supporting apparatus maintaining the basic body centrally and rotatably about its axis. The rotary movement imparted to the basic body-which is adapted to the relevant body diameter and to the welding speed-leads with a simultaneous horizontal and axial movement of the welding heads to the spirally oriented weld beads which, by fusing into one another, produce the application weld on the basic body.

In order to ensure that the basic body remains absolutely centric in spite of the welding heat influencing it, particular precautions must be adopted. The latter consist inter alia in that the supporting apparatus rotatably maintaining the basic body about its axis is constituted by supporting discs at each end of the basic body and with supporting members, which are connected frictionally to hollow journals, whilst the latter rest each upon a carriage provided with supporting rollers which are transportable in the axial direction of the basic body.

In this context the arrangement is made so that the drive end of the basic body serves as a fixed point, whereas the opposite end of the basic body, which likewise rests upon a carriage, can expand axially in adaptation to the thermal effect, and the carriage at the end remote from the fixed point is arranged to execute a corresponding horizontal movement.

The above-mentioned centric maintenance of the basic body is achieved by arranging the supporting members to be guided on rails on the supporting disc and are radially adjustable with reference to the basic body through spindles. This arrangement makes it possible for basic bodies of different diameter to be gripped by the tensioning device.

In order to enable the basic body maintained by the supporting apparatus to be optimally adjusted with reference to the welding device or the welding heads, it is also provided that the supporting rollers are adjustable both horizontally and vertically with reference to the hollow journal through a wedge transmission, operable for example, by spindles.

The invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows a side elevation of an apparatus in accordance with the invention, and Figure 2 shows an end elevation of the apparatus shown in Fig. 1 on a larger scale.

Referring to the Figures a basic body 10 of circular cross-section with a relatively small wall thickness (e.g., 30-50 mm) is supported at each opposing end by a hollow journal 6 which rests upon supporting rollers 8 of a carriage 5 that is provided with wheels, not referenced. A bracket 1 aupports a motor 2 with a thrust bearing 3, which is frictionally attached to one of the hollow journals 6.

The hollow journals 6 provided at both ends each carry a supporting disc 9 which is provided with rails 11 in which supporting members 7 are guided. The members 7 are adjustable in the radial direction, for example, by spindles etc., not shown, and in this way maintain the prefabricated basic body 1 O, which is made of a high grade steel. The supporting members 7, by coming radially into contact with the basic body 10 ensure that even in the event of a substantial thermal effect due to applied welds (described hereinafter) the basic body retains its circular shape. The thermal expansion of the basic body acting in the axial direction is compensated by the fact that the carriage opposite the drive end can move horizontally by virtue of its wheels.

The control mechanism relating to the welding units which are driven synchronously in a horizontal direction through a chain drive system, not shown, will for simplicity's sake, be described only in its essential features.

As may be seen from Fig. 1 an application weld 18 to be applied to the basic body 10 is generated by a plurality of welding heads 19, which form an entity each with a supply carriage 21, the carriage 19 accommodating a large stock of welding rod and welding powder. Each entity is mounted transportably on a common platform 22 and is liftable out of the latter by a crane not shown as soon as the relevent entity has attained its limit of travel i.e., the region of the left-hand end of the basic body (see Fig. 1). The entity is then transferred back into its initial position-i.e., the region of the right-hand end of the basic body-and commences with the production of a further spiral-shaped application weld bead.

In adaptation to the basic body 10 to be used in each case-which may of course differ in its diameter-e.g., 3,000-7,000 mm-the hollow journals 6 supporting the basic body 10 through the supporting discs 9 and supporting members 7 are mounted on supporting rollers 8, which are both horizontally and vertically adjustable through spindles 13 and 14 and a wedge transmission 15 and 17 (see Fig. 2).

To accommodate growth of the applied weld 18, from for example 400-700 mm, the welding head is capable of a corresponding variation, and so the welding heads 19 are mounted to be vertically readjustable.

The diameter of the basic body 10 used also differs from case to case and this is compensated by the fact that the platforms 22 accommodating the welding heads 19 and their supply carriages 21 are vertically adjustable through adjusting spindles 23.

Claims

1. An apparatus for rotatably supporting a cylindrical hollow body about an axis thereof, the wall thickness of which is to be increased by application of a weld, said apparatus comprising supporting discs arranged to centri cally support each end of the hollow body, supporting members which are radially adjustable with respect to the hollow body, the supporting discs being connected to journals, which journals each rest upon supporting rollers of a roller block.

2. An apparatus according to Claim 1, wherein the roller block is mounted on a carriage which is transportable in the axial direction of the hollow body.

3. An apparatus according to Claim 1 or 2, wherein the supporting members are guided in rails mounted on the supporting discs and that means is provided for the radial adjustment of the supporting members.

4. An apparatus according to any of Claims 1 to 3, wherein the supporting rollers are adjustable both horizontally and vertically with reference to the journals through the intermediary of a wedge transmission.

5. An apparatus according to any of Claims 1 to 4, wherein there is provided a drive unit comprising a motor and thrust bearing, which c6-operates with one of the journals supporting the hollow body.

6. An apparatus substantially as herein described with reference to and as shown in the accompanying drawings.