U.S. patent application number 12/086982 was filed with the patent office on 2009-07-02 for apparatus for and method of manufacturing helically wound structures.
Invention is credited to John Peter Booth.
Application Number | 20090165518 12/086982 |
Document ID | / |
Family ID | 35841206 |
Filed Date | 2009-07-02 |
United States Patent
Application |
20090165518 |
Kind Code |
A1 |
Booth; John Peter |
July 2, 2009 |
Apparatus for and Method of Manufacturing Helically Wound
Structures
Abstract
An apparatus (50) for and method of manufacturing helically
wound tubular structures (116) includes a rotating faceplate (74)
upon which are mounted a plurality of diameter defining rollers
(78) which, in operation, cause a strip material (80) to be
plastically deformed into a helical winding which may be lain down
in abutting or self-overlapping relationship to form said tubular
structure (116).
Inventors: |
Booth; John Peter;
(Yorkshire, GB) |
Correspondence
Address: |
NIXON & VANDERHYE, PC
901 NORTH GLEBE ROAD, 11TH FLOOR
ARLINGTON
VA
22203
US
|
Family ID: |
35841206 |
Appl. No.: |
12/086982 |
Filed: |
December 21, 2006 |
PCT Filed: |
December 21, 2006 |
PCT NO: |
PCT/GB2006/050471 |
371 Date: |
June 23, 2008 |
Current U.S.
Class: |
72/50 ;
156/466 |
Current CPC
Class: |
B21C 37/123 20130101;
B21C 37/12 20130101; B21C 37/126 20130101; B21C 37/128
20130101 |
Class at
Publication: |
72/50 ;
156/466 |
International
Class: |
B21C 37/12 20060101
B21C037/12 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 23, 2005 |
GB |
0526409.8 |
Claims
1. An apparatus for manufacturing a tubular structure of helically
wound strip comprising: a faceplate, mounted for rotation about a
longitudinal axis; a drive mechanism, for driving the faceplate in
a first direction about said longitudinal axis; and diameter
defining rollers, mounted on said faceplate for causing the strip
material to bend to a predetermined diameter prior to being formed
into a tubular structure.
2. An apparatus as claimed in claim 1 including an assembly of
shaping rollers, mounted for rotation with said faceplate and for
forming a cross-sectional profile on strip material prior to it
being formed to a pre-determined diameter.
3. An apparatus as claimed in claim 1 in which one or more of said
shaping rollers are driven rollers.
4. An apparatus as claimed in claim 2 in which the diameter
defining rollers include three mutually confronting rollers, one of
which is adjustable relative to the other two so as to cause any
strip material passing between said rollers to adopt a radius of
curvature defined by the positional relationship between said
rollers.
5. An apparatus as claimed in claim 1 in which said diameter
defining rollers include a pair of pinch rollers rotatable about
their own longitudinal axes and between which a strip of material
may pass and a ring roller which is adjustable relative to a first
pinch roller by rotation about the axis of the second.
6. An apparatus as claimed in claim 5 and including an actuator
connected to said ring roller for effecting adjustment relative to
said second pinch roller.
7. An apparatus as claimed in claim 1 including a reaction roller
against which forming forces exerted on any strip as it is caused
to adopt a radius of curvature by the ring roller will be
reacted.
8. An apparatus as claimed in claim 7 and including a second
actuator for causing the axial position of the reaction roller to
be varied relative to a pinch roller.
9. An apparatus as claimed in claim 1 in including an actuator for
effecting axial adjustment of one of said pinch rollers relative to
the other.
10. An apparatus as claimed in claim 1 including drive means for
driving one or more of said diameter defining rollers.
11. An apparatus as claimed in claim 5 including an actuator
connected to said ring roller for effecting adjustment relative to
said second pinch roller and including a computer coupled to said
actuator or actuators for controlling the positional relationship
of the roller or rollers.
12. An apparatus as claimed in claim 5 including an actuator
connected to said ring roller for effecting adjustment relative to
said second pinch roller and including an actuator connected to
said ring roller for effecting adjustment relative to said second
pinch roller and further including a computer coupled to said
actuator or actuators for controlling the positional relationship
of the roller or rollers further in which said computer comprises a
computer programmed to control said roller or rollers in accordance
with a predetermined programme.
13. An apparatus as claimed in claim 1 and including a first
gearing assembly mounted on said faceplate and driven from a fixed
gear arranged coaxially with said faceplate and in which said first
gearing assembly is engaged with said diameter defining rollers for
driving said diameter defining rollers.
14. An apparatus as claimed in claim 13 and further including a
second gearing assembly mounted on said faceplate and driven from a
fixed gear arranged coaxially with said faceplate and in which said
second gearing assembly is engaged with said forming rollers for
driving said rollers
15. An apparatus as claimed in claim 1 and including a main drive
member for driving said faceplate in said first direction.
16. An apparatus as claimed in claim 15 in which said main drive
member comprises a driven gear engaged with a corresponding gear
portion on said faceplate.
17. An apparatus as claimed in claim 1 and further including a
stock support for supporting a supply of stock of strip material
for being formed into a tubular structure.
18. An apparatus as claimed in claim 17 in which said stock support
comprises a circumferentially extending cassette extending around
said faceplate on an outer diameter thereof.
19. An apparatus as claimed in claim 17 in which said stock support
comprises a circumferentially extending cassette extending around
said faceplate on an outer diameter thereof and in which said
cassette comprises a plurality of support rollers circumferentially
spaced around the longitudinal axis and which cooperate with a
portion of a supply of strip stock and allow said stock to rotate
about said axis.
20. An apparatus as claimed in claim 17 in which said stock support
comprises a circumferentially extending cassette extending around
said faceplate on an outer diameter thereof, in which said cassette
comprises a plurality of support rollers circumferentially spaced
around the longitudinal axis and which cooperate with a portion of
a supply of strip stock and allow said stock to rotate about said
axis in which said support rollers are mounted for rotation about a
spindle secured to a non rotating portion of said assembly.
21. An apparatus as claimed in claim 1 in which the forming rollers
are staggered along said longitudinal axis and in which the axis of
rotation of said rollers relative to said axis varies in accordance
with the spiral angle of the strip as it passes from a supply
thereof to said diameter defining rollers.
22. An apparatus as claimed in claim 1 including a first strip
supply guide roller for guiding a supply of strip material from a
store thereof to said forming rollers.
23. An apparatus as claimed in claim 1 including a second strip
supply roller for guiding a supply of formed strip from said
diameter defining rollers to an inner diameter at which a tubular
member is to be formed.
24. An apparatus as claimed in claim 1 including an adhesive
applicator for applying an adhesive onto at least a portion of any
strip after it passes through said diameter forming rollers.
25. An apparatus as claimed in claim 24 in which said adhesive
applicator comprises an adhesive storing cassette for storing a
roll of adhesive strip.
26. An apparatus as claimed in claim 24 in which said adhesive
applicator comprises an adhesive storing cassette for storing a
roll of adhesive strip and in which said adhesive storing cassette
includes a spindle mounted on said faceplate for rotation therewith
and around which a supply of adhesive strip may be positioned and
rotate upon application of said adhesive strip to said tubular
structure forming strip.
27. An apparatus as claimed in claim 24 in which said adhesive
applicator comprises an adhesive storing cassette for storing a
roll of adhesive strip and the apparatus further comprises a
backing removing mechanism for removing any protective backing on
said adhesive strip prior to said adhesive strip being applied to
the tubular structure forming strip.
28. An apparatus as claimed in claim 1 in which the faceplate
includes a central hole for receiving a core liner onto which said
tubular forming strip may be wound to form a final tubular
structure.
29. An apparatus as claimed in claim 28 including a central support
trunion having a hollow centre which defines said central hole for
receiving said core liner.
30. An apparatus as claimed in claim 28 including a central support
trunion having a hollow centre which defines said central hole for
receiving said core liner and in which said support trunion is non
rotating and includes a gear thereon which forms said fixed gear
from which said rollers are driven.
31. An apparatus as claimed in claim 28 in which said apparatus
includes a support trunion and said faceplate is mounted for
rotation on the said support trunion.
32. An apparatus as claimed in claim 1 in which said faceplate
includes a receiving station for receiving a supply of flat strip
material to be formed into a tubular structure.
33. An apparatus as claimed in claim 32 in which said receiving
station comprises a ring having a diameter corresponding to the
diameter of the cassette, thereby to facilitate transfer of strip
material therebetween upon depletion of material from said
cassette.
34. An apparatus as claimed in claim 32 and including supply means
for supplying strip material to said receiving station as said
station rotates, thereby to wind said strip material onto said
receiving station in advance of material on said cassette being
depleted.
35. (canceled)
36. A tubular structure made on an apparatus as claimed in claim
1.
37. A method of manufacturing a tubular structure comprising the
steps of: bending a strip of material into a helical form by
plastic deformation thereof; and winding said bent strip in a self
overlapping manner into a tubular structure; wherein the strip is
bent into said helical form with a radius of curvature less than
the final radius of the structure to be formed.
38. A method as claimed in claim 36 and including the step of
passing said strip through a pair of pinch rollers and a ring
roller adjustable relative to one of said pinch rollers such as to
cause said strip to adopt said desired radius of curvature.
39. A method as claimed in claim 36 and including the step of
passing the strip through a pair of pinched rollers, the axis of
rotation of which are displaced relative to each other such as to
cause said strip to adopt a bend along its length thereby to impart
a sideways bend into said strip and create a strip having one edge
longer than the other.
40. A method as claimed in claim 36 and including the step of
applying an adhesive to portions of said strip which will be
overlapping when formed into a tubular structure.
41. A method as claimed in claim 36 in which the adhesive is
applied by applying the adhesive as a strip of adhesive to said
strip of material.
42. A method as claimed in claim 39 and including the step of
protecting said strip of adhesive by applying a protective coating
to at least one surface thereof and removing said protective
coating prior to applying said adhesive onto said strip which forms
said tubular structure.
43. A method as claimed in claim 36 and including the step of
providing a tubular core and winding said strip onto said core so
as to produce a tubular structure having an inner core and an outer
casing of helically wound material.
44. A method as claimed in claim 42 and including the step of
forming said tubular core by roll forming a strip of material along
its length and seam welding abutting longitudinal edges.
45. A method as claimed in claim 42 including the step of forming
said tubular core as a series of discrete lengths of tube and
assembling them into a continuous or near continuous length prior
to winding said strip material onto said core.
46. A method as claimed in claim 42 including the step of forming
said tubular core as a length of extruded pipe of a plastics
material.
47. A method as claimed in claim 42 including the step of providing
the core as discrete lengths of ceramic tube.
48. A tubular structure manufactured according to the method of
claim 36.
49. (canceled)
50. (canceled)
Description
[0001] The present invention relates to an apparatus for and method
of manufacturing helically wound structures and relates
particularly to the manufacture of pipes and longitudinal
structures formed by winding strips of metal in a helically
overlapping relationship. Other structures such as storage vessels,
towers and support structures may also benefit from features
described herein.
[0002] Presently it is known to manufacture tubular structures by
winding preformed metal strip onto a rotating mandrel such that the
strip is deposited onto the mandrel in a self-overlapping manner
and 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 and then swage over an edge of the strip 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 without having to stop the
machine.
[0003] It is also known to control the final diameter of the formed
pipe by controlling a plurality of radius forming rollers
immediately before the strip is wound into its final structure.
Such an arrangement is disclosed in U.S. Pat. No. 3,851,376 which
relates to a method and apparatus for forming a helical seam sealed
metal pipe in which the spring back force of the material is
controlled within permissible limits. A plurality of forming
rollers are provided for this purpose and include a three roller
arrangement of fixed rollers the position of which is selected and
set to impart a desired radius of curvature to a metal strip as it
passes through the rollers. An additional roller is displaceable in
response to a feedback signal indicative of the spring back force
so as to increase or decrease the forming force as necessary so as
to ensure the spring back force is maintained within desired
limits.
[0004] It is also known to elastically deform a metal strip and
wind it into a self overlapping helically wound structure and
employ an adhesive to maintain the strip in its final shape.
Unfortunately, the strip retains its desire to return to its
relaxed (flat) shape and the adhesive is necessary in order to
prevent the strip delaminating and unwinding. Additionally, the
final structure suffers from a high peel force created by the
stresses within the plastically deformed strip and these put a
great load on the adhesive itself, thereby compromising the
structural integrity of the structure and limiting its pressure
capacity significantly below its theoretical limit.
[0005] Whilst the above arrangements provide perfectly acceptable
methods of manufacturing pipes they either rely on plastic
deformation of an edge of the material strip to ensure the product
stays together or must rotate the final product during the forming
process, both of which can be problematic. For example, the force
required to deform an edge of the metal strip as it is lain down
onto a previously deposited layer and lock it thereto is
significant. Additionally, such machines consume unnecessarily
large amounts of energy and are very slow as operating such a
deformation process at high speed is extremely difficult. The
latter problem of having to rotate the product during forming
limits the use of this arrangement to the production of relatively
short sections of pipe and such sections must be joined if a long
section is required. When laying trans-continental pipelines it is
extremely undesirable to have to introduce any such joints as they
tend to be expensive to incorporate and problematic in
operation.
[0006] 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.
[0007] Accordingly, the present invention provides an apparatus for
manufacturing a tubular structure of helically wound strip
comprising: a faceplate, mounted for rotation about a longitudinal
axis; a drive mechanism, for driving the faceplate in a first
direction about said longitudinal axis; and diameter defining
rollers, mounted on said faceplate for causing the strip material
to bend to a predetermined diameter prior to being formed into a
tubular structure.
[0008] Preferably, the apparatus includes an assembly of shaping
rollers, mounted for rotation with said faceplate and for forming a
cross-sectional profile on strip material prior to it being formed
to a pre-determined diameter. One or more of said shaping rollers
may be driven rollers.
[0009] Preferably, the diameter defining rollers include three
mutually confronting rollers, one of which is adjustable relative
to the other two so as to cause any strip material passing between
said rollers to adopt a radius of curvature defined by the
positional relationship between said rollers.
[0010] In a particular arrangement the diameter defining rollers
include a pair of pinch rollers rotatable about their own
longitudinal axes and between which a strip of material may pass
and a ring roller which is adjustable relative to a first pinch
roller by rotation about the axis of the second.
[0011] In a most convenient arrangement the apparatus includes an
actuator connected to said ring roller for effecting adjustment
relative to said second pinch roller.
[0012] Advantageously, the apparatus may be provided with a
reaction roller against which forming forces exerted on any strip
as it is caused to adopt a radius of curvature by the ring roller
will be reacted.
[0013] Preferably, the apparatus includes a second actuator for
causing the axial position of the reaction roller to be varied
relative to a pinch roller. An actuator may also be provided for
effecting axial adjustment of one of said pinch rollers relative to
the other.
[0014] Advantageously, the apparatus includes drive means for
driving one or more of said diameter defining rollers.
[0015] In a particularly convenient arrangement the apparatus
includes a computer coupled to said actuator or actuators for
controlling the positional relationship of the roller or rollers.
Said computer may comprise a computer programmed to control said
roller or rollers in accordance with a predetermined programme.
[0016] Preferably, the apparatus includes a first gearing assembly
mounted on said faceplate and driven from a fixed gear arranged
coaxially with said faceplate and in which said first gearing
assembly is engaged with said diameter defining rollers for driving
said diameter defining rollers.
[0017] Conveniently, the apparatus further includes a second
gearing assembly mounted on said faceplate and driven from a fixed
gear arranged coaxially with said faceplate and In which said
second gearing assembly is engaged with said forming rollers for
driving said rollers. The apparatus may also include a main drive
member for driving said faceplate in said first direction which may
comprises a driven gear engaged with a corresponding gear portion
on said faceplate.
[0018] Conveniently, the apparatus includes a stock support for
supporting a supply of stock of strip material for being formed
into a tubular structure. The stock support may comprise a
circumferentially extending cassette extending around said
faceplate on an outer diameter thereof.
[0019] Conveniently, said cassette comprises a plurality of support
rollers circumferentially spaced around the longitudinal axis and
which cooperate with a portion of a supply of strip stock and allow
said stock to rotate about said axis. Said support rollers may be
mounted for rotation about a spindle secured to a non rotating
portion of said assembly.
[0020] In a particular arrangement the forming rollers are
staggered along said longitudinal axis and in which the axis of
rotation of said rollers relative to said axis varies in accordance
the spiral angle of the trip as it passes from a supply thereof to
said diameter defining rollers.
[0021] Conveniently, the apparatus may include a first strip supply
guide roller for guiding a supply of strip material from a store
thereof to said forming rollers. The apparatus may also include a
second strip supply roller for guiding a supply of formed strip
from said diameter defining rollers to an inner diameter at which a
tubular member is to be formed.
[0022] Advantageously, the apparatus includes an adhesive
applicator for applying an adhesive onto at least a portion of any
strip after it passes through said diameter forming rollers. Said
adhesive applicator may comprise an adhesive storing cassette for
storing a roll of adhesive strip. Said adhesive storing cassette
may include a spindle mounted on said faceplate for rotation
therewith and around which a supply of adhesive strip may be
positioned and rotate upon application of said adhesive strip to
said tubular structure forming strip.
[0023] The apparatus may further include a backing removing
mechanism for removing any protective backing on said adhesive
strip prior to said adhesive strip being applied to the tubular
structure forming strip.
[0024] Advantageously, the faceplate includes a central hole for
receiving a core liner onto which said tubular forming strip may be
wound to form a final tubular structure. Conveniently, there is
provided a central support trunion having a hollow centre which
defines said central hole for receiving said core liner.
[0025] Preferably, said support trunion is non rotating and
includes a gear thereon which forms said fixed gear from which said
rollers are driven.
[0026] Conveniently, said faceplate is mounted for rotation on said
support trunion.
[0027] Advantageously, said faceplate includes a receiving station
for receiving a supply of flat strip material to be formed into a
tubular structure. Said receiving station may comprise a ring
having a diameter corresponding to the diameter of the cassette,
thereby to facilitate transfer of strip material therebetween upon
depletion of material from said cassette.
[0028] Conveniently, the apparatus includes a supply means for
supplying strip material to said receiving station as said station
rotates, thereby to wind said strip material onto said receiving
station in advance of material on said cassette being depleted.
[0029] According to a further aspect of the present invention there
is provided a method of manufacturing a tubular structure
comprising the steps of: bending a strip of material into a helical
form by plastic deformation thereof; and winding said bent strip in
a self overlapping manner into a tubular structure; wherein the
strip is bent into said helical form with a radius of curvature
less than the final radius of the structure to be formed.
[0030] Preferably, the method includes the step of passing said
strip through a pair of pinch rollers and a ring roller adjustable
relative to one of said pinch rollers such as to cause said strip
to adopt said desired radius of curvature.
[0031] Advantageously, the method includes the step of passing the
strip through a pair of pinched rollers, the axis of rotation of
which are displaced relative to each other such as to cause said
strip to adopt a bend along its length thereby to impart a sideways
bend into said strip and create a strip having one edge longer than
the other.
[0032] The method may include the step of applying an adhesive to
portions of said strip which will be overlapping when formed into a
tubular structure. Said adhesive may be applied by applying the
adhesive as a strip of adhesive.
[0033] Advantageously, the method includes the step of protecting
said strip of adhesive by applying a protective coating to at least
one surface thereof and removing said protective coating prior to
applying said adhesive onto said strip which forms said tubular
structure.
[0034] Conveniently, the method includes the step of providing a
tubular core and winding said strip onto said core so as to produce
a tubular structure having an inner core and an outer casing of
helically wound material. Preferably, the step of forming said
tubular core is by roll forming a strip of material along its
length and seam welding abutting longitudinal edges.
[0035] Alternatively, the method may include the step of forming
said tubular core as a series of discrete lengths of tube and
assembling them into a continuous or near continuous length prior
to winding said strip material onto said core. Alternatively said
tubular core may be provided as a length of extruded pipe of a
plastics material.
[0036] In one arrangement said discrete lengths of tube are of a
ceramics material.
[0037] The present Invention will now be more particularly
described by way of example only with reference to the accompanying
drawings in which:
[0038] FIGS. 1 and 2 are partial cross-sectional views of two types
of tubular structure that may be formed by the apparatus described
herein;
[0039] FIG. 3 is a schematic side elevation of an apparatus
according to aspects of the present invention;
[0040] FIG. 4 is a side elevation of the forming head shown
schematically in FIG. 3
[0041] FIG. 5 is a front view of the forming head taken in the
direction of arrow A in FIG. 4;
[0042] FIG. 6 is a detailed view of the diameter forming roller
arrangement shown generally in FIGS. 4 and 5; and
[0043] FIG. 7 is a cross-sectional view of the pinch rollers taken
in the direction of arrows B-B in FIG. 6.
[0044] 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 comprises 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, as discussed above and an outer load
carrying casing discussed in detail later herein. 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 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. In accordance with one aspect of the
present invention the strip may be wound under tension. The strips
16 which form the outer casing 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 12o 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.
[0045] Referring now more particularly to FIG. 3, 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. 4 and 5.
[0046] Referring to the drawings in general but particularly FIG. 4
which is a side elevation of the forming station 56 and comprises a
faceplate 74 upon which are mounted a plurality of shaping rollers
76 and a set of diameter defining rollers, shown generally at 78.
As shown, the shaping rollers are profiled so as to form a
cross-sectional form to the strip as best seen in FIGS. 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 shaping rollers are
best provided as a plurality of confronting rollers (best seen in
FIG. 5) 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 shaping 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 shaping roller and on
another side with a sun gear 84 formed on a non rotating portion
86, which is described in detail later herein. As the faceplate 74
rotates in the direction of arrow C (FIG. 5) gears 76 and 82 rotate
therewith but as they are coupled to the sun gear 84 they are
caused to rotate about their axes and drive the strip through the
pinch formed between confronting shaping rollers 76. As shown, the
shaping rollers 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 radius forming rollers 78. In order to
ensure an even feed of strip material form a supply thereof it may
be desirable to provide a supply thereof in the form of stock
supply 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 portion of the stock of strip material
88 and allows the stock to rotate about axis X. The strip material
80 is removed from an inner diameter of said stock thereof and fed
via a first strip supply guide roller 94 mounted for rotation on
said faceplate 74 about an axis substantially perpendicular
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 via annular
portion 104 through which non rotating portion 86 extends.
[0047] Also shown in FIGS. 4 and 5 is the diameter defining roller
arrangement seen generally at 78 and 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.
This arrangement is best seen with reference to FIGS. 6 and 7 and
is described in detail later herein. An optional adhesive
applicator 106 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 108 is provided
with a roll of adhesive strip 110. The storage cassette 108 is
mounted for rotation about a spindle 112 mounted on the faceplate
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. 3). The strip of adhesive
may be provided in the form of a strip having a backing 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. 4 that the faceplate 74 includes a
central hole 114 for receiving a core or liner 54 onto which said
strip material 80 may be wound so as to form a final structure 116.
The central hole may be provided with a central support trunion 86
having a hollow centre which defines said central apperture 114 for
receiving said core or liner 54. When provided, the trunion may be
mounted within said central hole 114 by means of bearings 116, such
that said faceplate 74 can rotate about said trunion 86. Also shown
in FIG. 4 is a receiving station 118 in the form of ring 120 having
a diameter corresponding to the diameter of the cassette thereby to
facilitate the transfer of strip material therebetween upon
depletion of the material on the cassette. A supply of strip
material 122 forms a supply means for supplying strip material to
said receiving station as said station rotates, thereby to wind
said strip onto said supply station at the same rate as it is
depleted form said cassette.
[0048] Turning now to FIGS. 6 and 7 which illustrate in more detail
the format of the diameter forming rollers 78, it will be seen that
the rollers include a pair of pinch rollers 124,126 and a ring
roller 128 mounted on a pivot arm 130 pivotable about the axis of
rotation of one of the pinch rollers. It matters not which roller
axis the pivot arm rotates. An actuator shown schematically at 132
is connected to the pivot arm 130 so as to initiate and control
pivoting rotation of said ring roller in the direction of arrows
D-D in accordance with desired control parameters discussed later
herein. A further actuator 134 is provided to alter the position of
one of the pinch rollers 126 relative to the other 124 in the
directions of arrows E-E and F-F, again as discussed in detail
later herein. A final reaction roller 136 is provided in order to
react any forces experienced by the bending of the strip as it
passes between the pinch rollers and the ring roller 124, 126 and
128 respectively. This reaction roller may also be controllable by
actuator 138 so as to move it into or away from the strip 80 in the
direction of arrows G-G as required. FIG. 7 illustrates by way of a
cross-sectional drawing the actuator and roller control system in
more detail. From this drawing it will be appreciated that actuator
134 is preferably provided as a matched pair, one at each end of
roller 126 so as to allow differential and equal alteration of the
axial position of roller 126. In this particular arrangement the
actuator spindle 140 passes from the grounded actuator and through
a hole 142 passing through an upper block portion 144, past roller
spindle 46 (displaced relative thereto) and into lower block
portion 146 into which it is anchored at 148. A small gap 150
provided between the blocks such that displacement of spindle 140
will cause roller 126 to move closer to or away from roller 124 in
accordance with the actuator control parameters. Referring now more
particularly to drawings 6 and 7 collectively we will describe the
control principles. As mentioned above, roller 126 is adjustable in
the directions of arrows E-E and F-F by means of independently or
collectively controlled actuators 134a, 134b. Roller 128 is movable
in the direction of arrows D-D.sub.1 by actuator 132 and roller 136
is movable in the direction of arrows G-G, by actuator 138. Each
actuator is connected to and controlled by means of computer 140
(FIG. 3). In order to create the desired radius of curvature R on
the strip 80 before it is lain down to form a tubular structure one
simply needs to set and possibly adjust the position of roller 128
such that it causes the strip 80 to be bent about the axis of
roller 126 and plastically deformed such that the desired degree of
final bending is achieved after any spring-back effect. To set and
adjust the degree of pinch that the strip experiences as it passes
through pinch rollers 124, 126 one simply adjusts the axial
position of roller 126 relative to roller 124. This adjustment can
be a collective adjustment or a differential adjustment.
Differential adjustment will cause one side of the strip to be
pinched more than the other and if plastic deformation is induced
this will cause one side of the strip to adopt a length slightly
longer than the other. This arrangement helps the strip sit
comfortably as it is lain down on the previously deposited layer of
a multi-layer product. It will be appreciated that the longer edge
is the edge that is first deposited down as this will be the edge
that lies at the greater diameter and must fit to the diameter of
the layer underneath it. As an alternative to differential movement
In the direction of arrows E-E one might move roller 126
differentially in the direction of arrows F-F which will have a
similar affect on the differential thickness. Should it be
necessary to increase or alter the degree of bending the strip is
subjected to then it may be necessary to adjust the axial position
of roller 136 by actuating actuator 138 and move roller 136
appropriately.
[0049] Referring now once again to FIG. 3, an optional post forming
section 58 may include such things as an optional drive mechanism
152 and adhesive curing heater 154.
[0050] 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 shaping
rollers 76 and into diameter defining rollers 78 at which point the
desired diameter is formed by appropriate positional control of
rollers 124, 126 and 128. As the strip exits the diameter defining
rollers it is directed towards the core 54 and wrapped therearound
in a self overlapping arrangement best appreciated with reference
to FIGS. 1 and 2. Before the strip is finally deposited onto the
core it may be supplemented by an adhesive dispensed as a strip
thereof form dispenser 106. 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 the secondary supply
from station 118 across to the cassette 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 position to
ring roller 128 so as to change the rolling radius as required.
This process may be controlled by the computer 140 in accordance
with a predetermined control methodology.
[0051] Additional features of this machine include feedback control
from the computer to ensure the product diameter is maintained
within desired limits and/or altered according to desired
parameters. It will be appreciated that as one can control the
degree of plastic deformation of the strip as it passes through the
radius forming rollers one can also control the final diameter of
any tubular structure formed by this apparatus. One important
feature of this machine is its ability to form the radius of
curvature R such that it is slightly less than that of the core
onto which it is to be wound. Such an arrangement has a significant
affect on the final product as a strip so formed (to a smaller than
required radius) as the outer helically wound strip will
effectively grip the previous layer or the core and ensure close
contact therebetween and thus provide a better mechanical joint
therebetween than might be possible without this feature.
Additionally, by plastically deforming the strip rather than
elastically deforming the strip as is known in the art one will be
placing any adhesive used under far less or possibly no peel
loading at all, thus helping to maintain the integrity of the final
structure and increasing its pressure capacity closer to its
theoretical maximum.
[0052] 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.
* * * * *