CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a United States national phase application under 35 U.S.C. §371 of International Patent Application No. PCT/GB2010/050057 filed on Jan. 14, 2010, and claims the benefit of Great Britain Patent Application No. 0900724.6 filed on Jan. 16, 2009, both of which are herein incorporated in their entirety by reference. The International Application was published as International Publication No. WO 2010/082061 on Jul. 22, 2010.
FIELD
The present invention relates to a winding apparatus and a method of manufacturing structures and relates particularly to the manufacture of pipes and longitudinal structures formed by winding strips of material, such as metal, Kevlar, plastic, glass fibre, composites of such materials or strips formed from layers comprising one or more of said materials in a helical relationship. Other structures such as storage vessels, towers and support structures may also benefit from features described herein.
BACKGROUND
Presently it is known to manufacture tubular structures by winding pre-formed metal strip onto a rotating mandrel such that the strip is deposited onto the mandrel in a self-overlapping manner. The strip is retained in place by mechanical deformation of an edge thereof such that it interlocks with an adjacent edge, thereby to retain the strip in place on the final structure. EP0335969 discloses an apparatus for forming a helically wound tubular structure formed from a flat strip of metal wound onto a mandrel. The flat strip is fed from one or other of a pair of supply spools mounted concentrically with the axis of the tubular structure to be made. A rotating winding head is used to wind the strip onto the mandrel and includes a plurality of powered forming rollers which impart an initial form to the cross section of the metal strip before it is passed to a final set of rollers that lay the strip onto the mandrel. An edge of the strip is then swaged over so that it becomes mechanically locked to the previous layer over which it is wound. This is a complex process. Also provided is a mechanism for ensuring the strip supply is maintained constant and this mechanism includes speed control of the forming rollers. The coaxial supply bobbins are fed from an external supply spool so as to maintain the supply thereof. A welding station is used to join one end of the strip material to another.
U.S. Pat. No. 4,738,008 discloses a winding apparatus for forming a non-rotating helix of metal strip having a rotating store of metal strip provided radially outward of a winding head and means for providing the store of material to the winding head which rotates at a different speed to the store of material. In this process it is necessary to stop the process when the strip material has been consumed and a fresh supply thereof is added before production can be commenced. This can be a very lengthy process.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an apparatus for and method of manufacturing tubular structures which reduces and possibly overcomes some of the problems associated with the prior art.
Accordingly, the present invention provides a winding apparatus comprising an inner faceplate rotatably mounted for rotation about a longitudinal axis X-X and having an output station thereon; and an outer faceplate radially outward of said inner faceplate; wherein said inner faceplate includes a plurality of inner strip supports at an outer diameter thereof and onto which, in operation, a supply of material may be wound, said outer faceplate includes a plurality of outer strip supports and in which said inner strip supports comprise rollers mounted for radial displacement relative to said faceplate and said outer supports comprise rollers mounted for radial displacement relative to said inner rollers, thereby to accommodate a variable diameter of strip material. Such an arrangement provides support for the inner diameter of strip material as it is consumed and thereby helps maintain the integrity of the material and the balance of the apparatus as it rotates.
The apparatus may further include a plurality of inner pivot arms pivotally connected at a first end to said inner portion and provided with an inner support roller at a second end thereof and may also includes a plurality of outer pivot arms pivotally connected at a first end to said outer portion and including an outer support roller at a second end thereof.
Preferably, said inner or outer pivot arms are curved along its length so as to allow them to nestle amongst each other when retracted.
Advantageously, said pivotal connection arms and associated rollers are axially displaced relative to each other along a longitudinal axis X of the apparatus.
Preferably, said apparatus includes a first driving mechanism for rotating the inner faceplate about longitudinal axis X-X and may also include a second drive mechanism for driving said outer faceplate about said longitudinal axis X-X.
Advantageously, the apparatus further includes a faceplate brake for preventing rotation of said outer faceplate relative to said inner faceplate.
Conveniently, the apparatus further includes a pair of feed/clamp rollers for receiving a supply of strip material to said apparatus and for guiding said strip towards said inner faceplate.
Preferably, said apparatus further includes a strip clamping and cutting station.
Advantageously, said inner faceplate further includes a central bore for receiving a supply of core material onto which strip supplied to said apparatus may be wound.
Preferably, said apparatus further includes a core supply mechanism for supplying a continuous or semi-continuous supply of core material to said apparatus.
According to another aspect of the present invention there is provided a method of forming a tubular article on an apparatus comprising an inner faceplate rotatably mounted for rotation about a longitudinal axis X-X and having an output station thereon; and an outer faceplate radially outward of said inner faceplate; wherein said inner faceplate includes a plurality of inner strip supports at an outer diameter thereof and onto which, in operation, a supply of material may be wound, said outer faceplate includes a plurality of outer strip supports and in which said inner supports comprise rollers mounted for radial displacement relative to said faceplate and said outer supports comprise rollers mounted for radial displacement relative to said inner rollers, thereby to accommodate a variable diameter of strip material, the method comprising the steps of: winding a supply of strip material between said inner and outer rollers; consuming material from an inner diameter of said supply; and re-filling said apparatus with strip material by connecting a fresh supply thereof to an otherwise free end of said part consumed strip and rotating said inner portion thereby to draw material onto said inner rollers. Such an arrangement provides for the speedy charging and refilling of the strip stock.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will now be more particularly described by way of example only with reference to the accompanying drawings in which:
FIGS. 1 to 3 are partial cross-sectional views of different types of tubular structure that may be formed by the apparatus described herein;
FIG. 4 is a schematic side elevation of an apparatus according to aspects of the present invention;
FIG. 5 is a cross-sectional view of the winding head according to one aspect of the present invention;
FIG. 6 is a front view of the forming head shown in FIG. 5 and for reasons of clarity omits some features shown in FIG. 5;
FIG. 7 is a detailed front view of the winding head taken in the direction of arrow A in FIG. 5;
FIG. 8 is a partial plan view of the winding head taken in the direction of arrow P in FIG. 7; and
FIGS. 9 to 11 are end views of the winding head and illustrate various stages in the operation thereof.
DESCRIPTION OF THE EMBODIMENTS
Referring now to FIG. 1 of the drawings, a tubular body indicated generally at 10 forms a pipe for use in a pipe system such as a pipeline carrying hot fluids (which may also be under pressure). The tubular body may comprise an inner portion in the form of an inner hollow core 12 which may be formed by any one of a number of forming processes known to those skilled in the art and an outer casing discussed in detail later herein and which may also be load carrying. In the preferred process the inner pipe comprises a continuously formed core, as will also be discussed in detail later herein however, one may have a core made from a plurality of discrete lengths inter-engaged with each other so as to form a long length. The outer casing indicated generally at 14 is formed on the inner hollow core 12 by helically winding a strip 16 of material onto the outer surface 12a of the core 12 in abutting or self-overlapping fashion similar to the manner which is described in detail for the formation of a pipe on a mandrel in the specific descriptions of the applicants U.K. Patent No. 2,280,889 and U.S. Pat. No. 5,837,083. The strip may be wound under tension and may have one or more transverse cross-sectional steps 18 and 20 each of which is preferably of a depth corresponding to the thickness of the strip 16. The steps 18, 20 are preferably preformed within the strip 16, each extending from one end of the strip 16 to the other to facilitate an over-lapping centreless winding operation in which each convolution of the strip accommodates the overlapping portion of the next convolution. Whilst the strip may comprise any one of a number of materials such as a plastic, a composite material or indeed metal, it has been found that metal is particularly suitable in view of its generally high strength capability and ease of forming and joining as will be described later herein. Examples of suitable metals include steel, stainless steel, titanium and aluminium, some of which are particularly suitable due to their anti-corrosion capabilities. The internal surface 16i of the strip 16 and the outer surface of the pipe 12a may be secured together by a structural adhesive, as may the overlapping portions 16a of the strip. The use of an adhesive helps ensure that all individual components of the tubular member 10 strain at a similar rate. The application of the adhesive may be by any one of a number of means but one particularly suitable arrangement is discussed in detail later herein together with a number of other options.
FIG. 2 illustrates an alternative arrangement in which the flat strip 16 is formed such that step 28 divides the strip into longitudinal portions and is also provided with ridges 30 running longitudinally thereof. The ridges are shaped to produce an external ridge and an internal groove into which an external ridge of a previously deposited portion nestles during forming.
FIG. 3 illustrates a still further arrangement in which the strip comprises a simple flat strip wound in abutting relationship and provided in multiple layers which may be staggered as shown.
Referring now more particularly to FIG. 4, from which it will be seen that an apparatus 50 for manufacturing helically wound structures comprises: an optional pre-forming portion 52, in which a core 54 is formed; a forming station, shown schematically at 56 and described in detail later herein; and a post forming section, shown generally at 58 and including a number of optional features discussed later. In one arrangement of the optional pre-forming portion 52 there is provided a store of flat strip material in the form of a roll of metal strip 60 and a plurality of feed rollers 62 which feed the strip to forming rollers 64 and 66 which in turn roll the edges of the strip together around a central mandrel 68 so as to form a tubular structure 54 having confronting edges abutting each other (not shown). A welding apparatus shown generally at 70 and including a welding head 72 is used to weld together the confronting edges in a manner well known in the art and therefore not described further herein. An alternative core forming process might comprise the manufacture of a plurality of discrete lengths of tubular structure, each of which are provided with inter-engaging features on confronting ends thereof such as to allow a plurality of said lengths to be assembled into a long section of core. When employing such a core arrangement one may replace the strip forming and welding arrangement with a suitable feed mechanism (not shown) for feeding a plurality of said discrete lengths into the forming station in a continuous manner. Once formed, the core of whatever description is fed into the forming station 56, which is best seen with reference to FIGS. 5 and 6. Referring now once again to FIG. 4, an optional post forming section 58 may include such things as an optional drive mechanism 152 and adhesive curing heater 154.
Referring now to the drawings in general but particularly FIG. 5 which is a side elevation of the forming station 56 and comprises a faceplate 74 upon which are mounted a plurality of forming rollers 76 and a set of diameter defining rollers, shown generally at 78. As shown, the forming rollers are profiled so as to form a cross-sectional form to the strip as best seen in FIG. 1 or 2. It will, however, be appreciated that the forming rollers could impart an alternative form to the strip or may, in some circumstances, be eliminated all together. When provided, the forming rollers are best provided as a plurality of confronting rollers (best seen in FIG. 6) between which the strip 80 is sandwiched as it passes therebetween so as to impart the desired profile into the strip in a progressive manner, with each pair of rollers increasing the deformation of the strip until the final desired profile is formed. As shown, the forming rollers are each driven by means of a drive gear 82, each of which is mounted for rotation about an axis on said faceplate and engages on one side with a forming roller and on another side with a sun gear 84 formed on a non rotating or driven portion 86, which is described in detail later herein. As the faceplate 74 rotates in the direction of arrow D (FIG. 6) rollers 76 and gears 82 rotate therewith but as the rollers are coupled to the sun gear 84 they are caused to rotate about their axes and drive the strip through the pinch formed between said confronting forming rollers 76. As shown, the forming rollers 76 are each slightly staggered along longitudinal axis X and the axis of rotation of each roller varies in accordance with the spiral angle as the strip 80 passes from the supply thereof to the diameter defining rollers 78. It will, however, be appreciated that a simpler non staggered arrangement may be used where there is sufficient room to shape the strip and then position it correctly before applying it to the diameter defining rollers 78. It will also be appreciated that both the forming rollers and/or the diameter defining rollers may be driven by a servo system or motor shown schematically at 79.
In order to ensure an even feed of strip material from a supply thereof it may be desirable to provide a supply thereof in the form of an annular stock supply shown generally at 88. Advantageously this stock supply may be provided in a cassette or stock support 90 comprising a plurality of support rollers 92 positioned outside of said forming station and being circumferentially spaced around longitudinal axis X. Said support rollers 92 cooperate with a outer portion S2 of the stock of strip material 88 and allows the stock to rotate in the direction of arrow D about axis X. The strip material 80 is removed from an inner diameter (S1) of said stock thereof and fed via a first strip supply guide roller 94 mounted for rotation on said faceplate 74 about an axis angled relative thereto. In order to drive the faceplate 74 one may provide a motor 96 and gear drive 98 coupled to a ring gear 100 provided on a back plate 102 which is directly linked to face plate 74 via annular portion 104 through which portion 86 extends. Also shown in FIGS. 5 and 6 are a plurality of inner strip supports in the form of a plurality of rollers 110 provided at an outer diameter of said inner faceplate 74. The rollers of FIG. 5 are rotationally mounted to the inner faceplate 74 by means of rolling pins 112 which are circumferentially spaced around the circumference thereof. The pins 112 themselves are mounted for rotation in corresponding holes shown at 114 and positioned towards the end of pivot arms 113. Whilst the operation of these rollers will be described in more detail later herein, it will be appreciated that the rollers are each radially translatable and mounted to rotate about the axis of the pin and thus support or guide inner portion S1 of the supply of strip material 88 as it is consumed from an inner diameter.
Referring now to FIGS. 5 to 7, it will be appreciated that the outer support rollers 92 are mounted in circumferentially spaced relationship around an outer faceplate 118 and the faceplate be provided with a drive mechanism shown generally at 120 in FIG. 7. The drive mechanism comprises a motor or servo mechanism 122 having a gear 124 which drives ring gear 126 which is coupled to outer faceplate 118 so as to drive said plate 118 and rollers 92 as and when desired. In operation the motor 122 drives gear 124 which turns 118 which drives the collective set of rollers 92 en mass in a clockwise or counter clockwise direction. The rollers 92 are supporting the outer diameter S2 of the strip material 80 and, in turn, drive the outer diameter thereof in the direction of arrow D or E in FIG. 6. The outer rollers 92 are each connected to the outer faceplate 118 by means of pivot arms 128 similar to those provided in connection with the inner rollers 110. The pivot arms 128 are each pivotally connected to outer faceplate 118 by means of pins 130, best seen in FIG. 5. It will be appreciated from FIG. 7 that arms 113 and 128 are each preferably curved or cantered so as to allow the arms to nestle against each other in a particularly compact manner. In addition to this curvature, the arms may also be curved, cantered or angled along axis X so as to allow the arms to sit in side-by-side relationship when nestled together. This arrangement is shown schematically in FIG. 8 in which, for the purposes of clarity, just one arm is shown. It will be appreciated by those skilled in the art that other forms of drive mechanism could include motors 122a and 122b coupled directly or indirectly to rollers 92, 110 (best seen in FIG. 5).
From FIG. 7, it will be appreciated that inner and outer arms 113, 128 are able to swing so as to allow their respective rollers 110 and 92 to move radially inwardly or outwardly as may be required. The motion is in an arch as shown by dotted line Ar and whilst this motion will cause a degree of circumferential displacement this is easily accommodated by the rollers rolling along the surface of S1 or S2 as required. The rollers in this arrangement are able to keep in supporting contact with the strip material throughout the depletion process keeping it as one coherent mass which will assist with the maintenance of balance as the faceplates rotate. The rollers may be provided with a friction surface such as a rubber coating (not shown) in order to facilitate gripping of the strip material when required. Actuators shown schematically at 213 and 228 are provided for moving arms 113 and 128 as and when necessary or desired.
The diameter defining roller arrangement seen generally at 78 which, between them, act to curve the strip material by plastically deforming it around one of the rollers such as to define the diameter of the exiting strip are not central to the present application and the reader's attention is drawn to the present applicant's patent application PCT/GB2006/050471 which describes this feature in detail. An optional adhesive applicator 132 may also be mounted on the faceplate 74 for rotation therewith. The applicator may take a number of forms for supplying adhesive to the strip after it has been formed and one particular arrangement is shown in which a storage cassette 134 is provided with a roll of adhesive strip 136. The storage cassette 134 is mounted for rotation about a spindle 138 mounted on the faceplate 74 for rotation therewith such that, upon rotation of the faceplate, adhesive strip may be dispensed onto the surface of the strip 80 as it is lain down onto the core 54 (FIG. 5). The strip of adhesive may be provided in the form of a strip having a backing (not shown) and this backing may be removed by backing removing means (not shown) prior to said adhesive being applied.
It will be appreciated from the cross-sectional view of FIG. 5 that the faceplate 74 includes a central hole 140 for receiving a core or liner 54 onto which said strip material 80 may be wound so as to form a final structure 142. The central hole may be provided with a central support trunion 86 having a hollow centre which defines said central aperture 140 for receiving said core or liner 54. When provided, the trunion may be mounted within said central hole 140 by means of bearings 142, such that said faceplate 74 can rotate about said trunion 86.
Referring to the drawings in general, it will be appreciated that a tubular structure may be manufactured by causing the faceplate 74 to rotate. This action in turn will cause the strip material 80 to be drawn from the cassette, passed through forming rollers 76 and into diameter defining rollers 78 at which point the desired diameter is formed by appropriate positional control of the diameter defining rollers 78. As the strip exits the diameter defining rollers it is directed towards the core 54 and wrapped therearound in a self overlapping or abutting relationship as shown in FIGS. 1 to 3. Before the strip is finally deposited onto the core it may be supplemented by an adhesive dispensed as a strip thereof from dispenser 130. Continuous rotation of faceplate 74 will cause continuous deformation and deposition of the strip 80 and this process will continue so long as there is a supply of strip material within the cassette store. Once the strip material has been depleted it is necessary to transfer fresh material onto the apparatus from a supply station (not shown) and weld one end to the other before recommencing operations. It will also be appreciated that some forms of structure need not have a core and the above process may be undertaken without a core being supplied to the faceplate. In such an arrangement it may be necessary to provide a support to the initial portion of tubular structure formed but once an initial portion has been formed the structure will be self supporting as new layers are effectively deposited down on a stable multi layer structure. Indeed, one may well adopt such an arrangement when it is desirable to form a tapered structure for which one would find it difficult to produce a tapered inner core. Structures without cores are, therefore, within the scope of the present invention. In the production of such a tapered structure it is simply necessary to vary the degree of bending applied to the strip and this can be done by applying a variable force to the diameter defining rollers 78 so as to change the rolling radius as required. This process may be controlled by the computer shown schematically at 150 in accordance with a pre-determined control methodology.
Referring now briefly to FIG. 7 which illustrates the inner support rollers in more detail, it will be appreciated that, whilst the location and support may take any one of a number of forms, the arrangement of FIG. 7 is particularly compact and allows the diameter of the structure to be kept to a minimum. The features of FIG. 7 that might possibly not be appreciated from FIG. 5 include the way in which arms and are spaced around the circumference thereof so as to provide substantially even support for the strip 88. Additionally, it will be further appreciated that a compact design may be formed by placing the inner rollers on as small a diameter as possible whilst avoiding the arms 113 conflicting with the forming mechanisms. Still further, it will be appreciated that the strip 88 is fed from the inner diameter of the supply thereof and passes between two of said support rollers 110 as it is supplied to the first of the forming rollers 76. One of said rollers may act as a guide roller to replace 94 as shown in FIG. 6. The primary function of the inner support rollers 110 is to provide a support mechanism onto which the strip material 88 may be wound and through which it may be dispensed to the winding head. Each roller 110 is mounted for rotation on a spindle 112 which is, in turn, mounted on the inner portion 102 via roller support arm 113, best seen in FIG. 7. In operation the strip material may slide over rotating inner rollers 110 as it is supplied to the winding station.
It will be appreciated that whilst the inner rollers 110 and the faceplate 74 are shown in two different planes in FIG. 5 they may be provided in the same plane. In such an arrangement the forming rollers 76 and diameter defining rollers 78 are simply provided at a diameter smaller than that of the support rollers 110, as shown in FIG. 7. FIGS. 9 to 11 illustrate a set of clamp/feed rollers 160 positioned at an outer diameter of the winding head, the function of which will be described later herein.
The various stages of the winding process and replenishment steps will now be more particularly described with reference to FIGS. 9 to 11.
In FIG. 9 there will be seen a completely wound supply of strip material 88 which has been wound onto the winding head by rotating inner faceplate 74 (at and thereby drawing a length of strip material onto the inner rollers 110). One may clamp the strip material so as to prevent it being supplied to the forming rollers and simply complete the re-stocking thereof. In this mode, strip material is supplied to the forming station by rotating the inner faceplate such as to pull fresh material through rollers 110 and onto the partially depleted supply of strip material supported by the inner rollers. This process is continued until the space between the inner and outer rollers 110, 92 is filled, at which point the apparatus is ready to commence or re-commence pipe production. At this time, the rollers 92, 110 will be at their respective radial extremities. During the “winding on” process it is also possible to produce an amount of pipe as the required material is taken from an inner diameter of the coil of material 88 and new material is added to an outer diameter thereof. It will be appreciated that by virtue of the difference in diameters of the pipe and that of the inner support rollers material will be consumed by the forming station at a much lower rate than it will be added to the support rollers 110. FIG. 10 illustrates the next step in the process at which point several meters of strip material has been wound onto the former so as to produce a section of pipe and virtually all of material 88 has been removed from the inner diameter. During this process one of the inner support rollers 110 also acts as a guide roller as the strip material changes direction as it rolls thereover. As the strip material is consumed a gap opens up between the forming rollers and the bulk of the strip supply at S2 and the inner rollers 110 have to move radially outwards in order to support the strip 88 which is now at a much larger diameter. Once the strip supply is almost depleted the apparatus is stopped and outer portion 118 is reversed such as to allow the otherwise free end 88a of the strip to be fed back through clamp/feed rollers 160 at which point it can be joined to a fresh supply thereof by, for example a simple welding process followed by a subsequent and optional grinding of the weld so as to make a smoother joint. The weld portion is shown schematically at 162 in FIG. 11.
FIG. 11 illustrates the commencement of a building step in which material is added to the inner rollers 110. At this point both sets of rollers 92, 110 are moved radially inwardly to the position shown such as to allow new strip material to be added at an inner diameter rather than an outer diameter. One is able to transfer strip material from the fresh supply thereof to the inner rollers at whatever speed that one rotates inner faceplate 74, which is done by actuating motor drive 96 of FIG. 5. Outer rollers 92 are progressively moved radially outwards as the diameter of the new strip material increases. It will be appreciated that by virtue of the difference in diameter of the pipe being formed and that of the inner rollers 110 onto which fresh material 88 is being wound that significantly more material will be added per revolution than will be consumed by the formation of a pipe. Consequently, pipe production may be maintained whilst replenishing the stock of strip material. Once a full charge of fresh strip material has been wound on the winding process is stopped and the otherwise fee end of the fresh strip is allowed to feed through rollers 160 and be encompassed by rollers 92. At this point the recharging process is complete and the arrangement will look like that shown in FIG. 9. In some circumstances, it may be necessary to cut any unwanted fresh strip material off at the roller position and pass the new free end through said rollers.
Recommencement of the winding process simply requires for the continuation of the driving process in which faceplate 74 and the forming rollers are rotated about axis X so as to cause strip material to be drawn through the rollers and deposited onto the core. It will be appreciated that when used to produce a pipe having a self overlapping structure one need not provide a core as the pipe is, in effect, self supporting.
It will also be appreciated that the apparatus may be used on strips of other materials such as Kevlar, plastic, glass fibre, composites of such materials or strips formed from layers comprising one or more of said materials. Indeed the machine lends itself particularly to use with some of these materials as it is able to pre-tension the strip as it is wound onto the final form of the tubular structure being formed. When used with composite materials having a portion of metal in the strip provided either as a layer or as part of any woven form thereof, said metal will act to maintain a degree of rigidity in the strip that will assist with the location thereof on the rollers and in maintaining a final curvature. Materials such as glass-fibre or Kevlar may be reinforced by a resin or other such material in the manner well known to those skilled in the art and, therefore, not described further herein. Clearly, any such materials may simply be wound into the desired shape without needing to be provided with a cross-sectional profile as described earlier.
It will also be appreciated that the above described method and apparatus may be used to cover an already existing pipeline with an outer casing. In this arrangement the already existing pipeline forms a core and the machine simply rotates around the core and moves therealong so as to lay down the outer wrap of strip material onto the pipeline. Such an approach could be employed when one wishes to repair or strengthen an already existing pipeline.
Still further, it will be appreciated that if portion 86 (FIG. 5) is driven then it may benefit from being separately supported for rotation in bearings 200 provided in a fixed structure 202 and further provided with a drive mechanism shown generally at 204 and including, for example, a motor 206, driving gear 208 and driven gear 210, the latter of which is provided on portion 86. Preferably, the controller is also connected to the motor for control thereof and for this purpose one may also provide control line 212 shown generally in FIG. 6.
Patent Application
20120036910
