FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
PROVISIONAL / COMPLETE SPECIFICATION (See section 10 and rule 13)
1. TITLE OF THE INVENTION
A SEMI-AUTOMATIC EQUIPMENT FOR MANUFACTURING LONG COMPOSITE TUBES
2. APPLICANT
(a) NAME : Larsen and Toubro Ltd.
(b) NATIONALITY.: Indian Company, registered under the provisions of the
Companies Act, 1956
(c) ADDRESS : L&T House, Ballard Estate, Maharashtra State, India.
3. PREAMBLE TO THE DESCRIPTION

PROVISIONAL
The following spe invention

ton describes the

COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.

4. DESCRIPTION (Description starts from page 2)
5. CLAIMS: 7 Nos
6. DATE AND SIGNATURE: Given at the end of last page of specification.
"1STRACT OF THE INVENTION: On separate page

Title of the invention: A semi-automatic equipment for manufacturing long composite tubes.
Field of invention; The present invention relates to equipment for manufacturing long composite tubes/pipes by using pre-impregnated tapes. More particularly, it relates to equipment especially designed and constructed to manufacture long composite tubes by laying or winding of pre-impregnated tapes in both the directions i.e. circumferential and longitudinal, on a mandrel with flexible but precise process control parameters.
Prior art: In prior art, there are no means of manufacturing long composite tubes by simultaneous longitudinal laying of multiple tapes on a mandrel followed by a layer of tape wound on it circumferentially.
Conventionally, such composite tubes are manufactured by helical winding of fibre filaments on a mandrel of required diameter from one end to the other. Such layers of individual fibre strands are wound one on the top of the other till the required thickness of the tube is built i.e. the required outer diameter of the tube is obtained.
In this conventional method, strength of individual fibre is relatively very low as compared to fibre tapes. The necessary tension cannot be given to each strand with equal pitch for the entire length is near impossible. This uneven pitch and uneven tension on each individual fibre filament leads to uneven strength at different points on the circumference of the same tube. Here

the strength in circumferential and longitudinal direction is obtained, but complete fibre strength utilisation is just not possible as is thus a grave limiting factor in the conventional manufacturing process. For optimal and efficient fibre strength utilisation, simultaneous laying in longitudinal and circumferential direction is necessary, but this is impossible when individual fibre strands are used as a raw material for the manufacturing of composite tubes. Also, it is practically difficult to make large diameter i.e. 500mm diameter and extra long i.e. 10000mm tubes by fibre filament winding process as it will be very cumbersome, time consuming, highly unreliable and very costly. A heavy process rejection due to breakage/ entanglement of individual strands during the winding of fibres from multiple spools is a reality with no escape route. Thus the desired quality of complete tubes remains a pipe dream, in spite of using the best available quality of fibre filaments and resins. The overall conventional process is also very costly.
DEFICIENCIES OF PRIOR ART:
1. Optimum utilisation of fibre strength is not possible.
2. Strength of tube varies at different points on the cross-section for the entire length and is not uniform as desired.
3. Rejection of process and finished goods is inevitable and heavy.

4. Process is time consuming and requires constant monitoring and attention of experienced machine attendants.
5. Process involves high expenditure.
PRESENT INVENTION:
With a view to overcome the deficiencies found in the prior art, the present invention is introduced. The present invention is an equipment and subsequent process for simultaneous and synchronized laying of pre-impregnated fibre tapes from multiple spools in longitudinal direction i.e. left to right or right to left, on a mandrel which is immediately followed by another pre-impregnated tape, of the required width, which is helically wound on it during the same pass and in the same direction i.e. left to right or right to left respectively. Both the longitudinal laying and circumferential winding are done from one end of the mandrel to the other and are repeated over and over again till the required diameter of the tube is built up and the longitudinal and circumferential layers are on top of the other till the tube is complete. It is developed for the manufacture of uniform and homogeneous high quality, highly reliable, high strength long composite tube/pipes on an semi-automatic equipment and more so economically. The objective of this invention is to automate the manufacturing process and also enhance the strength of the long composite tubes by making optimum utilisation of the fibre

strength in both the circumferential/hoop as well as longitudinal
directions without increasing its weight.
Another objective of the present invention aims is substantially
increasing the strength of long composite tubes by laying and
winding of fibre tapes in a predetermined manner. For e.g.: the
longitudinal tape layers are laid on the mandrel, which is
simultaneously followed by the circumferential layer of tape
InetaWy, wound on it. Thus, these tapes are iaid and wound
alternately one above the other, the significance being that the
laying and winding (cross ply winding) is semi-automatic and is
perfectly synchronised to give a homogeneous defect free cross
section.
Yet another objective of this invention is to mass produce high
quality and highly reliable long composite tubes, with nearly zero
inter-laminar defects, wherein all design and constructional
parameters like tape tension, tape overlap, tape tackiness, tape
compactness etc. can be both individually and collectively
controlled.
The present invention is directed towards the process of
manufacturing homogeneous long composite tubes of the
required thickness, size, length and the designed strength for
specific critical applications by a specially designed process and
on specially designed equipment.
The scope of the present invention covers the ways and means of
enhancing productivity to economise the process in general by
reducing the process time substantially.

Summery of invention: This invention "A semi-automatic equipment for manufacturing long composite tubes", comprises; a power spindle for mounting and rotating the mandrel, carriage with orbiting drive to support the tape laying and guiding arrangements, radiation heaters for making the tape tacky so that bonding between layers is positive, tensioning device for all tape spools, dead weight for compaction of the tapes during winding and the control panel for controlling and co-ordinating all movements. The spindle rotation and orbiting drive are electrically coupled so that the spindle & the orbiting ring are perfectly synchronised with each other. The tape laying and winding can be carried out during both the directions of travel of the carriage i.e. from head stock end to tail stock end or vice versa.
Statement of the invention: A semi-automatic equipment for manufacturing long composite tubes comprising of a main frame (!), machined guide ways called bed (2), and on the vertical portion of the main frame (1) the drive motor (12) being housed, the spindle (3) being provided to support, hold and rotate the mandrel (4) fixed on the spindle (3); the carriage (5) being placed on the guide ways (2) of the bed and driven by electric drive motor (12); the longitudinal spools 6a and 6a being mounted on the spool holders 21a and 21b, the spools 6a and 6b being provided with tensioning arrangement 20a, tension measuring device being provided for measuring and adjusting the

tension on the tape while laying longitudinal tapes on the mandrel and to cover the entire surface of the mandrel with the required tape overlap; a tape guide roller 23a being used to release the tape very near to the mandrel 4; the hot air guns or radiation heaters being provided above the tape guide roller 23a to control the tackiness of the pre-impregnated tape; the spool holders21a being fitted in the slotted rings 8a and 8b, provided on both sides i.e. the right and the left; these slotted rings being firmly secured on the orbiting ring 9 mounted on the carriage 5; the drive motor 11 for orbiting ring being electrically coupled with the spindle drive motor 12; hoop spools 15 being mounted on the carriage 5 to provide for the tape getting wound over the longitudinal tapes during movement of the carriage; the hoop spool being provided with, shaft 20, bush bearing 21, bobbin 22, stopper ring 23; tensioning arrangement provided by means of spring washers 25, nut 26 and a collapsible handle 27; dead weight rollers 13a and 13b actuated by pneumatic cylinders 110 being provided to compact the; laid tapes when the carriage 5 moves from head stock end to tail stock end.
ADVANTAGES OF INVENTION:
1. Maximum possible fibre strength utilisation is achieved.
2. Both circumferential/hoop and longitudinal strength for the entire length is uniform.
3. Manufacturing process is semi-automated.

4. Rejection during process and also in finished goods is drastically reduced.
5. Manufacturing process is comparatively simplified, is less time consuming and also does not require constant attention of experienced skilled operators.
6. The entire manufacturing process is economical.
Description:
The invention is now described in detail with help of following
figures.
Fig A shows the front view of the invention.
Fig B shows the side view of the invention
Fig C shows the details of longitudinal tape spool holder with
tensioning device
Fig D shows circumferential tape holder and the tensioning
device.
Fig E shows the orbiting ring with two slotted rings fitted on it.
As shown in Fig. A to E, the invention semi-automatic equipment
for manufacturing long composite tubes comprises following. A
main frame (1) Machined guide ways called the bed (2). The
vertical portion of the main frame houses the drive and supports
the mechanism of the spindle (3). The spindle (3) is securely held
in the chuck or any other driving arrangement. The spindle (3) is
used to support, hold and rotate the mandrel (4). This mandrel is
fitted on the spindle. The spindle is driven by a variable geared

drive to rotate at the required speed by changing the gear in the gearbox. The carriage (5) is placed on the guide ways of the bed and moves linearly from left to right or right to left as required during operation. The carriage is designed to accommodate all the tapes and process control arrangements. The complete carriage moves linearly over the machine bed in perfect coordination with the spindle rotation to obtain a uniform winding of tape on the mandrel (4). Longitudinal spools 6a & 6b are mounted on spool holders 7a & 7b for laying of longitudinal tapes on the mandrel. As many spools required are put to cover the entire surface of the mandrel with the required tape overlap, are provided on it. The spools 6a & 6b are mounted on the spool suppor+s 21a & 21b; the spool holders 7a and 7b are fastened to the slotted ring 8a & 8b. Two slotted rings are further assembled on the either sides of the orbiting ring 9. This is clearly visible in Fig A & Fig B. The orbiting ring is mounted on the carriage and it has teeth cut on its circumference to facilitate power transmission through timer belt (10) to achieve synchronizing rotation with respect to the rotation of the spindle. The drive motor (11) for the orbiting ring is electrically coupled and synchronised with the spindle drive motor (12). Dead weight roller (13a) is used for compacting the tapes, when the carriage is moving from head stock end to tail stock end. The dead weight roller is actuated by a pneumatic cylinder (110). Similarly, dead weight roller 13b, slotted ring 8b, spools 6b are functional when the laying and winding progresses from tailstock end to head stock end.

Fig. B shows the side view of the carriage with longitudinal spools 6a, fitted in its respective slots on the slotted ring 8a. The mandrel (4) rotates in clockwise/anticlockwise direction as required for the winding of circumferential tape (14) with the help of circumferential tape holder (15), the tension of the tape is adjusted by the tensioning device (16) and tension measuring device (17), During winding of the circumferential tapes from left to right, adequate tension through out the process is necessary for maintaining straightness of tape fibres along with the ironing effect of the dead weight rollers, to give sufficient compactness to the cross section of composite tube. Radiation heaters (not shown in the drawing) are also provided in the roller to heat the tapes so as to achieve required tackiness of the tapes for proper sticking with one another in order to give a uniform homogeneous structure and to eliminate inter laminar defects in it. The heat of these radiation heaters is also adjustable to suit the ambient temperature and also to suit the various material systems. Temperature controlling units are provided in the control panel to increase and decrease the heat for desired tackiness. The control panel (not shown) electrically and electronically controls and synchronises the rotation of spindle and the orbiting ring and also the liner motion of the carriage.
Fig. C shows the longitudinal tape 7a in its spool 6a along with its tensioning device 20a. Longitudinal tape spool support 21a is provided for mounting the tape spool for longitudinal laying. These spool supports are firmly secured to the slotted ring

by means of bolts 22a. The tape is straightened by passing it through rollers 23a and is guided and released very near to the surface of the mandrel to avoid wavy pattern. The number of spool holders and tensioning device in actual use is the same as the number of spools being actually used for a particular diameter composite tube.
Fig, D shows a schematic drawing of circumferential/ hoop tape holder and tensioner. It shows bearing shaft (20) is fitted in a bush bearing (21). A bobbin (22) for holding the circumferential tape spool is fitted on the shaft. Stopper ring (23) is fitted at one end of the bobbin. Spacer ring (24) is fitted adjacent to the stopper ring and disc springs (25) are used to exert pressure on the spool for obtaining necessary tension on the circumferential tape. A collapsible handle (27) is used to rotate nut (26) for adjusting the pressure of spring to vary the tension on the tape as required. All these adjustments are required because a tape wound in the circumferential direction requires adequate tension to control straightness of the tape fibres and also to achieve necessary compactness. The bobbin of the tape tension is designed to accommodate tapes of different widths.
Fig. E shows a schematic drawing of the orbiting ring (9) which houses the two slotted rings 8a and 8b. The orbiting ring has teeth (100) cut on its outer diameter to match the teeth of the timer belt, which drives it to achieve synchronised rotation with the spindle rotation. Orbiting ring is supported in the carriage and maintains its concentricity with the spindle at all times. The slotted ring has slots cut on its face to hold the spool

holders. Desired overlap of longitudinal tape is achieved by deciding the geometric pattern of these slots. Slotted rings are bolted to the orbiting ring. Tapped holes are provided for fixing spool holders in each slot by means of socket head cap screws.
During actual working of the equipment, when the direction of motion of the carriage (5) is from left to right the free ends of all longitudinal pre-impregnated fibre tapes are secured in longitudinal direction at the left hand end on the mandrel (4) by tying it on a clipping flange mounted on the mandrel. The free end of the circumferential tape is also secured at the left hand end of the mandrel, but in circumferential winding direction. The equipment is then switched on and the spindle (3) starts rotating and also the mandrel (4) fitted on it, say in anticlockwise direction. As soon as the mandrel (4) starts rotating, the orbiting ring (9) also starts rotating with the mandrel (4) at a synchronous speed so as to maintain zero relative motion between them The entire carriage (5) starts moving from head stock end to tail stock end at a pre-set speed. All these three motions are perfectly synchronised so that as the carriage (5) gradually moves from left to right the longitudinal tapes are laid along their length & the circumferential tape is wound above them.
Preset overlaps can be achieved in longitudinal as well as the hoop tapes. During this winding, the tape is heated with a hot air blow near the mandrel so that the resins in the fibre tape reach a tacky state and hence it sticks positively to the longitudinal laid tape beneath it and each helical turn also sticks

to the earlier helical turn on the overlapped portion. As soon as the process of winding starts, a pneumatic cylinder (110) activates a dead weight roller (13a). This dead weight roller (13a) has in-built radiation heaters (not shown in drawing). These heaters preheat the tape and thus control its tackiness as desired and it compacts the wound tape to the required level.
The carriage gradually moves from extreme left to extreme right of the mandrel to complete one pass of all the tapes. Number of such passes are made on top of the other till the required thickness of the tube is built and homogeneous composite tube is formed.
In this equipment, it is possible to start tape lay up from both the ends of the mandrel (4) i.e. from left as well as right side. Also, the laying and helical winding of tape is possible by rotating the mandrel in either anticlockwise or clockwise direction.

WE CLAIM:
1. A semi-automatic equipment for manufacturing long composite tubes comprising of a main frame (1), machined guide ways called bed (2), and on the vertical portion of the main frame (1) the drive motor (12) being housed, the spindle (3) being provided to support, hold and rotate the mandrel (4) fixed on the spindle (3); the carriage (5) being placed on the guide ways (2) of the bed and driven by electric drive motor (12); the carriage (5) is placed on the guide ways of the bed to accommodate all tapes, tape laying and process control apparatus which moves linearly over the machine bed in perfect co-ordination with the spindle rotation to obtain a uniform winding of tape on the mandrel; for longitudinal laying of tape spools (6a) and (6b) being mounted on the spool holders (21a) and (21b), the spools (6a) and (6b) being provided with tensioning arrangement (20a), tension measuring device being provided for measuring and adjusting the tension on the tape while laying longitudinal tapes on the mandrel and to cover the entire surface of the mandrel with the required tape overlap; for measuring the tension it uses spring balance to display the tension in the tape; a tape guide roller (23a) being used to release the tape very near to the mandrel (4); said mandrel can rotate in either anticlockwise or clockwise direction for laying the tape accordingly; the hot air guns or radiation heaters being provided above the tape guide roller (23a) to control the

tackiness of the pre-impregnated tape; the spool holders (21a) being fitted in the slotted rings (8a) and (8b), provided on both sides i.e. the right and the left; these slotted rings being firmly secured on the orbiting ring (9) mounted on the carriage (5); the drive motor (11) for orbiting ring being electrically coupled with the spindle drive motor (12); spindle drive is provided with a gear box so as to set required speeds; hoop spools (15) being mounted on the carriage (5) to provide for the tape getting wound over the longitudinal tapes during movement of the carriage; the hoop spool being provided with, shaft (20), bush bearing (21), bobbin (22), stopper ring (23); tensioning arrangement provided by means of spring washers (25),nut (26) and a collapsible handle (27); dead weight rollers (13a) and (13b) actuated by pneumatic cylinders (110) being provided to compact the laid tapes when the carriage (5) moves from head stock end to tail stock end.
2. A semi-automatic equipment for manufacturing long composite tubes as claimed in claim 1 wherein, orbiting ring 9 houses two slotted rings 8a & 8b and is having teeth cut on its circumference to facilitate power transmission through timer belt 10 for achieving synchronised rotation with respect to the rotation of the spindle 4; the slots in the rings 8a & 8b are provided to hold the spool holders 21a &