GB2030511A

GB2030511A - Pipe making apparatus and method

Info

Publication number: GB2030511A
Application number: GB7902939A
Authority: GB
Original assignee: Rocla Concrete Pipes Ltd
Current assignee: Rocla Concrete Pipes Ltd
Priority date: 1978-09-01
Filing date: 1979-08-22
Publication date: 1980-04-10
Also published as: JPS5559912A; FR2434691A1; GB2030510A; FR2434692A1; DE2933958A1; DE2933924A1; GB2030510B; JPS5559911A; ZA794480B; ZA794479B; AU5006079A; BR7905628A; GB2030511B

Abstract

Roller suspension process and apparatus for manufacture of pipes of concrete or other cementitious material. An open ended tubular pipe mould 13 is suspended on a horizontal suspension roller 16 extending through the mould and the mould is rotated by driving the suspension roller. Cementitious material is fed into the mould as it is rotated so as to be spread evenly around the mould and is compacted by the suspension roller. After compaction of the pipe wall, lower sets of wheels 21 are raised to lift the mould and allow it to rotate at reducing speed. Consequent relief of compaction pressure and peripheral speed differential between support roller and rotating pipe wall causes the support roller to burnish the inner surface of the pipe wall and eliminates slumping of pipe wall when mould comes to rest. <IMAGE>

Description

1 GB 2 030 511 A 1

SPECIFICATION

Pipe making apparatus and method This invention relates to the manufacture of pipes of concrete or other cementitious material and is concerned particularly with the manufacture of pipes by what is generally known as the "roller suspension process".

The basic roller suspension process if fully described in Australian Patent No. 118,079. In this process an open ended pipe mould is suspended from one or more horizontal suspension rollers extended longitudinally through the mould and the mould is rotated by driving the suspension roller, or at least one of them if there be two or more such rollers. A cementitious material, for example concrete, is fed into the mould as it is rotated so as to be spread evenly around the mould by centrifugal action and compacted by the suspension roller or rollers.

The forms of apparatus advanced in Australian Patent 118,079 for carrying out the roller suspension process have proved most successful and apparatus of this type is still in operation. The later Australian Patent No. 430, 389 discloses a modified type of roller suspension apparatus which is particularly suited to mass production of pipes and in which individual handling of the pipe moulds is much reduced.

The present invention provides certain modifications in the basic roller suspension process and apparatus, whereby it is possible to improve the internal finish of the pipe and to reduce slumping in the pipe wall. The modifications of the present invention may be used in combination with certain other improvements which are the subject of our co-pending patent application 7929224 entitled "MANUFACTURE OF PIPES".

The present invention provides pipe making apparatus comprising:

a tubular pipe mould; one or more elongate, generally horizontal mould suspension rollers to extend longitudinally within the pipe mould and support internally; drive means to rotate the mould when supported on the suspension roller or rollers whereby a pipe can be formed by depositing a cementitious material within the mould as it is rotated to build a pipe wall which is compacted by the support roller or rollers; and mould raising means operable to raise the pipe mould relative to the mould support roller or rollers when the mould is rotating and to cause a peripheral speed differential between the support roller or rollers and the pipe wall while the support roller remains in contact with the rotating pipe wall whereby to burnish the inner surface of the pipe wall.

The mould raising means may comprise two sets of mould lifting wheels to engage the mould exterior at or adjacent the opposite ends of the mould and wheel lifting means operable to lift those rollers and thereby raise the mould.

The invention further provides a method of mak- ing a pipe comprising the steps of supporting a tubular pipe mould on a suspension roller or rollers extending longitudinally within the mould; rotating the thus supported mould; depositing a cementitious material within the thus supported and rotating mould to build within the mould a pipe wall which is compacted by the suspension roller or rollers; wherein the rotating pipe mould is raised relative to the support roller or rollers to relieve compaction of the pipe wall and a peripheral speed differential is generated between the support roller or rollers and the pipe wall while the suspension roller is still in contactwith the pipe wall whereby to burnish the inner surface of the pipe wall.

In order that the invention may be more fully explained one particular embodiment will be described in detail with reference to the accompanying drawings in which:

Figure 1 is a side elevation of a roller suspension machine constructed in accordance with the invention; Figure 2 is a vertical cross-section on the line 2-2 in Figure 1 showing the condition of the machine when building and compacting a pipe wall within a mould; and Figure 3 is a cross-section corresponding to Figure 2 but showing the condition of the machine at completion of a pipe forming operation.

The illustrated machine comprises a main machine frame 11 which carries horizontal mould suspension roller 12 to support a tubular steel pipe mould 13. At one ends of the machine, which will be referred to as the "rear" end, roller 12 is supported in a bearing 14 and is connected to a drive shaft 15 driven by an electric motor (not shown). Atthe other (front) end of the machine, roller 12 is supported in a bearing 16 mounted in a swinging gate which can be swung outto open the front of the machine for insertion and removal of successive pipe moulds.

Pipe mould 13 comprises the usual main cylindrical section 17 and an enlarged cylindrical end portion 18 within which to form a pipe socket end. The two ends of the mould have internal running rings to run on the suspension roller 12 as the wall of the pipe is being built up.

As thus far described, the illustrated roller suspension machine is of conventional construction. In contrast with conventional equipment, however, the illustrated machine is provided with two sets of upper compaction wheels 19 and two sets Qf lower mould lifting wheels 21, and the mould is provided at its ends with external running rings 23 to engage these wheels. Running rings 23 may be steel rings welded to the pipe mould so asto project radially outwardly and to extend circurnferentially around the end of the mould.

The upper compaction wheels 19 are disposed in two pairs (front and rear) arranged to engage the running rings 23 at opposite ends of the mould and the wheels of each pair are disposed to opposite sides of a central vertical plane through the axis of the mould support roller 12. The wheels 19 of each pair are mounted on shafts 26 carried on the outer ends of a pair of double-plate levers 27 the inner 2 GB 2 030 511 A 2 ends of which are pivotally connected by pins 28 to a structure 25 fixed to the main machine frame and housing a hydraulic cylinder unit 29. The piston rod 31 of unit 29 is fitted with a cross-arm 32 to the ends of which the upper ends of a pair of thrust rods 33 are pivotally connected by pivot pins 34. The lower ends of thrust rods 33 are connected by pivot pins 35 to midportions of levers 27. The hydraulic cylinder unit can be actuated to move thrust rods 33 up and down whereby to swing levers 27 about their inner pivot connections to structure 25 and thereby to raise and lower wheels 19. The hydraulic cylinder units for the two sets of wheels are interconnected hydraulically so that both sets of rollers can be raised and lowered together.

The upper wheels 19 at the forward end of the machine have circumferential grooves 36 to track on the respective external running ring 23 of the mould and thereby locate the mould axially of the support roller 12. The upper wheels 19 at the rear end of the machine have smooth cylindrical rims 37.

The lower mould lifting wheels 21 are also arranged in two pairs disposed one pair at each end of the mould. Each pair of lifting wheels is mounted on a pair of parellogram linkages comprised of links 90 41,42,43.

The upper links 41 of these linkages are pivotally mounted on the main machine frame by pins 44 and brackets 45 and their outer ends carry shafts 46 for the lifting wheels 21. Each link 42 comprises a pair of spaced plates pivotally connected to the respective wheel shaft 46 at opposite sides of the wheel 21. The other end of link 42 carries a pivot pin 47 whereby it is connected to the respective link 43, which is also formed by double plates.

The bottom links 43 of the parallelogram linkages are rigidly connected to a pair of shafts 48 extending one along each side of the machine and mounted on the main machine frame by end bearing brackets 49.

These shafts can be counter-rotated by an actuating mechanism 51 wherebythe parrallelogram linkages can be moved to raise and lower the wheels 21.

Actuating mechanism 51 comprises a pair of lever arms 52 projecting outwardly from shafts 48 and interconnected by a link 53 formed by two parallel plates 53A. Link 53 can be moved by operation of an hydraulic cylinder unit 55 disposed between the two plates 53A. The cylinder of unit 55 is connected to a fixed abutment 60 by a trunnion 56 and the piston rod is pivotally connected to link 53 via an adjustable screw thread connector 57. Extension of cylinder unit 55 causes counter-rotation of shafts 48 in directions which swing the parellelogram linkages upwardly to lift wheels 21 to the position shown in Figure 3, whereas retraction of unit 55 causes opposite rotations of the shafts to lower the wheels to the position shown in Figure 2.

As indicated in Figure 3, the parallelogram link ages are mounted on the machine frame such that when wheels 21 are raised to engage the running rings 23,24 of the mould the links 41, 43 are substantially horizontal and the wheels can therefore be moved substantially vertically to lift the mould from suspension roller 12. The lifting rollers at the front of the machine have circumferential grooves 58 130 to track on the front running ring of the mould and thereby to maintain positive location of the mould axially of the support roller.

In operation of the illustrated machine, the mould 13 is initially supported on roller 12 with both the upper compaction wheels 19 and lower lifting wheels 21 in retracted positions is.e. with the upper wheels raised and the lifting wheels lowered. The suspension roller 12 is then driven by the electric drive motor to rotate the mould and the upper compaction wheels 19 are forced downwardly by operation of the respective hydraulic cylinder units 29 to force the mould firmly against the support roller. Concrete is deposited within the mould by means of a travelling belt conveyor (not shown) which is inserted within the mould and traversed longitudinally so as to discharge concrete along the length of the mould. The concrete is distributed evenly around the mould to form a pipe wall which is compacted by the suspension roller 12. Because the upper wheels 19 force the mould downwardly, much greater compaction forces are generated than in a conventional roller suspension machine in which the compaction forces are due solely to the weight of the mould and its contents. Moreover, the upper wheels serve to hold the mould in a stable position during the filling and compaction operations.

When a compacted pipe wall is formed within the pipe mould the upper wheels 19 are retracted or raised and the lower wheels 21 are also raised to slowly lift the pipe mould relative to suspenion roller 12. As the mould is raised slowly, it passes through a condition in which the suspension roller 12 maintains light contact with the pipe wall. At this stage the suspension roller does not compact the pipe wall appreciably nor can it drive the pipe mould which accordingly slows down and eventually comes to rest. As the mould slows down a peripheral speed differential exists between suspension roller 12 in the pipe wall in that the suspension roller continues to rotate at relatively high speed and the pipe wall gradually slows to rest. The rotating roller 12 thus performs a burnishing or smooth finishing operation on the inner surface of the pipe, so eliminating or reducing the need for subsequent trowelling as presently carried out on pipes produced bythe roller suspension process. The mould is raised bythe lifting wheels until the pipe is lifted clear of suspension roller 12 as shown in Figure 3.

The illustrated apparatus enables many significant improvements over conventional roller suspension machines. Firstly it is possible to achieve a consistently strong and dense concrete with less cement than hitherto. This is due not only to the increased level of compaction obtained but also because the compaction time can be reduced to minimize pulverization of the aggregate in the concrete. Moreover, more consistent conditions can be reproduced.

The upper wheels also greatly reduce lateral sway and bouncing of the mould during the filling and compaction operation. In a conventional roller suspension machine the mould sways quite severely during the filling stage and also bounces about when aggregate is caught between the suspension roller and the internal running rings. These movements of c 3 GB 2 030 511 A 3 the mould severely limitthe size of concrete delivery conveyorthat can be inserted into the mould and therefore the speed with which the mould can be filled. In the apparatus of the present invention the mould is positively held in a stable position and it can be filled much faster. Operating noise levels are also much reduced by the elimination of mould bouncing. The compaction and lifting wheels may include rubber inserts or sleevesfitted with steel rims in order to minimise operating noise levels and to absorb vibration.

The tracking of the grooved wheels on the front running ring of the mould positively locates the mould longitudinally of the suspension roller and provides much better location than in conventional machines in which it is necessary to rely on stop rings fitted to the suspension roller. The external running rings also have a much increased bearing area and therefore a longer life than the convention- al stop rings.

As already mentioned the provision of the mould lifting wheels enables the internal surface of the pipe to be sleek finished mechanically by the suspension roller before the mould is removed from the machine and eliminates the need for subsequent hand trowelling. Raising the mould in this way also avoids the problem of slumping of the pipe wall as can sometimes occur in a conventional machine due to the tendency for the concrete to adhere to the suspension roller when the pipe-filled mould is allowed to come to rest while fully supported on the suspension roller. The lower wheels can also be operated to reduce starting loads on the main drive motor in that the mould can initially be supported on the lifting wheels when the rotation of the suspension roller begins and the lifting wheels then lowered to place the mould on the suspension roller.

The illustrated machine has been advanced by way of example only and it could be modified considerably. For example, means could be provided to rotate the mould lifting wheels so as positively to drive the mould at a lower peripheral speed than the suspension roller in order to extend the burnishing period. If the lower rollers are positively driven, the main suspension roller could be braked and reversed for burnishing. Means to drive the lower wheels at low speed would also facilitate positioning of the mould with the mould seam to the bottom before the mould is lifted from the machine in order to eliminate slumping of the 115 pipe wall due to air pressure acting through the mould seam.

Instead of relieving the force on the compaction wheels prior to the mould lifting steps, the means for raising the lifting wheels may be such as to be capable of lifting the mould against the continued action of the upper compaction wheels. In this case the mould could be positively driven by the upper wheels during the burnishing period. The mould could, of course, be driven via the upperwheels during filling and compaction, rather than through the main support roller.

Although in the illustrated construction only the front sets of upper and lowerwheels are grooved to provide axial location of the mould it will be 130 appreciated that the rear sets of wheels may additionally, or alternatively, be so grooved orflanged. The pipe socket may be at either end during casting.

It is also not essential that the front bearing of the suspension roller be carried on a swinging gate since other means could be used to provide a releasable connection for mould loading and unloading. For example, it is also known to provide horizontal arms carrying part-circular bearings which can be brought into contact with the suspension roller.

In a further modification, the main suspension roller could be movable longitudinally to enable the moulds to be side-loaded into the machine in the manner described in Australian Patent 430,389.

It is accordingly to be understood thatthe invention is in no way limited to the details of the illustrated machine norto the process carried out with that particular machine and that many modifi- cations and variations will fall within the scope of the appended claims.

Claims

1. Pipe making apparatus comprising:

a tubular pipe mould; one or more elongate, generally horizontal mould suspension rollers to extend longitudinally within the pipe mould and support it internally; drive means to rotate the mould when supported on the suspension roller or rollers whereby a pipe can be formed by depositing a cementitious material within the mould as it is rotated to build a pipe wall which is compacted by the support roller or rollers; and mould raising meansto raise the pipe mould relative to the mould support roller or rollers when the mould is rotating and to cause a peripheral speed differential between the support roller or rollers and the pipewall while the support roller remains in contact with the rotating pipewall whereby to burnish the inner surface of the pipe wall.

2. Pipe making apparatus as claimed in claim 1, wherein said mould raising means comprises two sets of mould lifting wheels to engage the mould exterior at or adjacent the opposite ends of the mould and wheel lifting means operable to lift those wheels and thereby raise the mould.

3. Pipe making apparatus as claimed in claim 9, wherein the mould has radially outwardly projecting, circumferentially extending, external running rings at its opposite ends to engage the two sets of mould raising wheels and at least one which of the sets of wheels is circumferentially grooved or flanged to track on the respective mould running ring.

4. A method of making a pipe, comprising the steps of supporting a tubular pipe mould on a suspension roller or rollers extending longitudinally within the mould; depositing a cementitious material within the thus supported and rotating mould to build within the mould a pipe wall which is compacted by the 4 GB 2 030 511 A 4 suspension roller or rollers; wherein the rotating pipe mould is raised relative to the suspension roller or rollers to relieve compaction of the pipe wal I and a peripheral speed differential is generated between the suspension roller or rollers and the pipe wall while the suspension roller is still in contact with the pipe wall whereby to burnish the inner surface of the pipe wall.

5. A method as claimed in claim 4, wherein the pipe mould is rotated during compaction of the pipe wall by driving the support roller or rollers and the rotating pipe mould is raised by means of wheels on which the mould rotates at reduced speed.

6. A method as claimed in claim 5, wherein the mould is raised by said wheels so as to be supported clear of the support roller or rollers and is allowed to rotate at reducing speed until it comes to rest.

7. Pipe making apparatus substantially as hereinbefore described with reference to the accom- panying drawings.

8. A method of making a pipe substantially as hereinbefore described with reference to the accompanying drawings.

Printed for Her Majesty's Stationerv Office by Croydon Printing Company Limited, Croydon Surrey. 1980. Published bythe Patent Office, 25 Southampton Buildings, Lorclon,WC2A lAY, from which copies may be obtained