CA1202288A - Winding a package of tape - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Tape is wound into a package by traversing the winding position along a cylindrical core such that the winding position is intermittently and repeatedly halted at a plurality of positions arranged axially of the core so that at each position the tape is wound spirally following which the winding position is traversed to the next adjacent position. The spirals comprise at least one turn and more of the winding time is spent in forming spirals than in traversing between spirals.
The spacing between the positions is such that the spirals do not overlap and such that the gap between the spirals is less than the width of the tape. The number of spirals wound at each position is insufficient to cause a step which interferes with traverse back to the position.
Control of the traverse movement can be achieved either electronically by a pulse counter connected to the package support shaft or electro-magnetically by a control drum driven from the package support shaft.

Description

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"WINDING A PACKAGE OF TAPE"

BACKGROU~D OF THE INVENTION
This invention relates to a method and appar-atus for winding tape onto a cylindrical core to form a package of the tape.
Tape is manufactured in many different dimen-sions from many materials for various end uses. One common problem however i5 that of winding the tape into a package for pay~off at a user station.
For many years tapes were wound onto a single spiral where one layer lies directly on top of the pre-vious layer, and most wrapping machines from which the package of tape is used were built to accommodate only such single spiral tapes. In more recent years as auto-mation and reduction of labour costs has become more important attempts have been made to form larger packages so as to reduce the labour content necessary to replace an empty package with a new full package on the wrapping machine.
In order to increase the amount of material in a package it is necessary to traverse the winding posi-tion axially of the cylindrical core on which the package is formed to form an elongate package much longer than ,~

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the width of the material ~o be wound. Traverse packages of tape have been manufactured successfully and have been sold for use with wrapping machines and other circum-stances but ~ecause of the slippery character of the tape involved they have been prone to telescoping and collapse of the ends or shoulders of the package in a fault known as edge drop off. This has been a serious problem in ~he industry and has limited the size of packages particular ly in relation to their diameter thus increasing the labour necessary to replace empty packages on the sub-sequent machines. In addition certain ~apes have been difficult or impossible to wind into packages of this type.
One example of an apparatus for winding tape particularly packaging ~ape or strapping is shown in U.S.
Patent 4,093,146 (Haley). This apparatus provides a dwell in the winding traverse at end positions on the package. Hcwever, apart from the small dwell angle which is controlled in conjunction with the number of turns in the traverse to locate the turn-around point at the end of the package at particular angular orientations, the package is substantially conventional.
Furthermore, Haley only teaches that the dwell angle should be small, that is very much les9 than 360 'r~

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and that when the dwell angle becomes larger (up to 270 is mentioned) the package is clear]y inferior to other packages where the dwell is only 36. The conclusion that must be drawn from this patent is therefore that a dwell at the ends of the package can be advantageous but that the advantage is only obtained at small angles and an increase of the dwell to as much as 270 removes that advantage.
The Haley package, being substantially of con-ventional structure therefore, does not provide a packag ing system :Eor tape which can effectively form a stable pacXage which avoids problems of telescoping or collapse of larger size packages.
Attention is also directed to the ~nited S~atespatents 3,025,015~and 3,836,090 both standing in the name of Robert C. Mix. The first patent discloses a unique core designed in an attempt to achieve a long yardage roll which comprises a conventional cylindrical core on the cylindrical surface o which is provided a plurality of arcuate ribs of the order of 1/2 inch in height.
These ribs are used to form a package from a plurality of single spiral windings otherwise known as pads with traverse sec1:ions between each single pad and the next when the pad reaches the height of the rib.

, T3 z~7 As will be apparent from the drawings of this patent, th~ structure formed is asymmetrical or eccentric and therefore unbalanced .in its rotation and also does not wind up or dispense ~ape ~.t a constant rate or uni form tension..
The latter patent mentions the first and states that it is a system for merely rewinding material once initially wound on a conventional package.
The latter patent relates to a system of combining pacls onto a specifically designed core so that when unwindi.ng each pad is interconnected with the next so that unwinding can transfer from each depleted pad throughout the full collection o pads on ~he core. Thus the patents are related in that they both provide an attempt to combine a plurality of pads onto a single package.
SUMMARY OF THE INVENTION
It is one object of the invention therefore to provide a me~hod and apparatus for forming a novel struc-ture of pac]cage from such tape, which package is rnore resistant to telescoping and collapse than previous packages.
According to a first aspect the inven~ion provides a method of building a package of tape having a ~,~

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right circular cylindrical winding surface comprising forwarding the tape from a supply thereof, guiding the tape to a wi.nding position on the core, rotating the core around its axis to wrap the tape around the core and traversing 1he winding position across the core to form the package, wherein the winding position is inter-mittently traversed to visit repeatedly during the pack-age build each in turn of a pair of separate end posi-tions spaced axially of the core and at each end position lOis maintain~ed stationary for a period of time greater than two ful.l turns of the core to wrap the tape spirally of the core so that the tape forms at a respect,ive one of the end positions a right circular cylindr.ical step coaxial to t'he core of increased radial height relative to another position~:at whi,ch the radial height has not been increased, in between 'said each end position and said another position ~he tape forming a helical traverse portion, said step having a height such that the tape can descend to said another position without interfering with 20said traverse of the tape following which at said another position further wraps of the tape are applied to build the radial height thereof up to that of the step.
According to a second aspect of the invention there is provided an apparatus for building a package of .............................................................. i ~,~

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tape having a right circular cylindrical winding surface wound on a core comprising a constant speed supply of the tape, support: means for the core, drive means for rotat-ing the core to wrap the tape therearound, guide means for guiding t.he tape onto the c~ore at a winding posikion, and traverse means for causing relative reciprocating movement between the guide means and the support means ~o traverse the windlng position axially of the core to build a pack;age, and traverse control means including traverse advance means arranged to intermit~ently advance : the traverse means such that the winding position visits each of a pair of separate end positions of the package spaced axially of the core repeatedly during the package build and m6!ans~ for halting the traverse means for a period of time such that the winding position remains at each said end position in turn to wrap the tape spirally of the: core~at the position to form a step thereat of increased radial height relative to ano~her position on the package,~said step having at least two full turns and a heiyht such that the winding position can traverse to said another portion to form a hellcal traverse portion of the tapa which descends form said step to said another position wi~hout interfering with ~he traverse of the tape.

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The invention therefore has the advantage that the package is formed substantially from a plurality of spirals arranged at the separate positions axially of the core with th~e spirals interconnected every few turns by a helical portion traversing from one spiral to the next~
This forms a package which is more rigid in structure than previouæ packages and particularly the ends or shoulders of the package are formed mainly from a spiral and thus are stronger and more resistant to telescoping than conventlonal cross wound packages.

The posi.tions are preferably spaced so that the separate spirals do not overlap but are separated only by a small extent to reduce the amount of traverse required to a minimum and to form a package of maximum density so as to contain the maximum material.
In this specification ~he terms spiral and helix are uslPd in the normal geometrical or mathematical definition w~lere a spiral is a plane curve generated by a point moving along a straight line while the line re-volves about ~ fixed point eg. a clock spring or roll of tape: and a helix is a space curve generated by a pointmoving along a straight line while the line revolves about another line, generally parallel to the first as an axis eg. a screw thread.

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It is a further important feature of the inven-tion that tht! traverse is maintained stationary at each position sufficiently to wrap at least one full turn of material at that position so that each helical traverse is locked int:o the next adjacent spiral by a number of turns. As arl e~ample only, the number of turns may lie between 1 and 5 complete turns for intermedia~e windings and between two and ten complete turns for the end wind-ings depending upon ~he thickness and handling character-is ics of the tape~ The turns cannot be sufficient to form an appr.eciable step in the package of for example one-half inch since the tape will be prevented from over-coming the step and continuing proper traverse.
With the foregoing in view, and other advan-tages as will become apparent to those skilled in the art tO which this invention relates as this specification proceeds, the invention is herein described by reference to the accompanying drawings forming a part hereof, which includes a description of the best mode known to the applicant an~ of ~he preferred typical embodiment of the principles o:E the present invention, in which:
DESCRIPTION OF THE DRAWINGS
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Figure 1 is a schematic isometric view of a winding apparatus for winding packages according to the ,, I r, .' t Z2~

invention and including electronic control of the package traverse.
Figure 2 is a schematic front elevation of a package formed according to the invention in which the step height and spacing have been exagc.~erated and the angular extent and position of the crossover have been distorted in order to provide an illustration of the package that is visually comprehensible in a two dimen-sional form.
Figure 3 is a schematic front elevation of a winding apparatus similar ~o that of Figure 1 but incorp orating electro-mechanical control of the package traverse.
Figure 4 is a schematic end elevation of a package formed in accordance with the invention in which the step height has been exaggerated as in Figure 2 but the angular extent of each crossover has been shown as a practical example of 180 degraes.
In the drawings like characters of reference

2~ indicate corresponding parts in the different figures.
DETAILED DESCRIPTION
The apparatus for winding tape shown schematic-ally in Figuce 1 incorporates many features of the appar-atus disclosed and claimed in my U.S. Patent -L~

No. 4,413,792 to which reference is made.
The apparatus comprises a stationary main frame lO which is shown only schematically but supports the drive motors and brackets necessary for the machine. The main frame lO is of conventional construction and hence is not shown in detail for s:implicity of illustration.
The main ~rame 10 provides guides for a tape 11 forwarded from a supply thereof (not shown). The tape 11 is one of a number of such tapes split from a film at an apparatus station upstream of the winding apparatus. A plurality of such tapes may be wound on the apparatus but only one winding statiGn i9 shown in Figure l.
A ~raversing support carriage 12 is provided adjacent the main frame 10 and as explained hereinafter can be traversed transversely to the direction of move-ment of the tape 11 to traverse the winding position of the tape along a cylindrical core to form a cylindrical pacXage. In practice the traversing support carriage 12 will support a number of winding positions 50 that they are traversed simultaneously to wind the tape 11 forward-ed from the supply.
The main frame lO carries a pair of pivot arms 13 which in turn support a package drive roller 14 car-ried on a shaft 15 and driven by a timing belt and pulley 2~

16. The arms 13 are freely pivoted on the main frame 10 so tha~ the roller 14 presses downwardly under its own weight onto a package supportecl by the traversing support carriage 12. A guide 17 comprises a shaft 171 supported on the arms 13 and a pair of collars 172 spaced by the width of the tape so that the tape passes over the shaft 171 between the collar~ 172 to be guided onto the roller 14 around which it is wrapped so as to maintain a con-stan~ position axially of the roller 14. The shaft 171 can support a number of further collàrs ~not shown) to guide further tapes issuing from the supply downwardly to further windi:ng positions (not shown).
The winding position on the traversing support carriage 12 comprises a shat 18 mounted in bearings 19 in upstanding side walls 20.of the carriage 12. In prac-tice each acldi.tional winding position (not shown) will include a shaft 18 mounted on the side walls 20. A
cylindrical core 21 on which the package is to be wound is mounted on the shaft 18 and the shaft 18 includes means (not shown) for releasing the package for replace-ment by an empty package when filled. ~
The shaft 18 extends beyond the side wall 20 at one end thereof and includes a sensor assembly 22 which rotates wlth ~he shaft 18, and senses the speed of rota-'{'.i...L~

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tion of the shaft 18 by issuing a series of pulses for each rotation of the shaft 18. The carriage 12 is mount-ed on anti-friction slides 24 which are conventional in form and it suffices to say that they allow transverse movement of the carriage 12. The carriage is driven in its traverse movement by a lead screw 25 on which a nut 26 is carried and a~tached to the side wall 20 of the carriage 12. The lead screw 25 is driven by a servo-motor 27 through a suitable gear reducer 28 both of which are mounted upon the main frame 10 again shown schematic ally. Thus the servo-motor 27 acts to rotate the lead screw 25 by a controlled amount whereby the nut 26 is moved axially of the lead screw to traverse the carriage 12 by a predetermined amount.
Pulses from the ~sensor 22 are detected by a programmable controller 29 which may be a Potter &
Brumfield Series 1000, 1200 or equivalent. Control information issuing from the controller 29 is communi-ca~ed to the servo-motor 27 via electronic control system 30 so as to control the servo-motor 27 in dependence upon the condition of the package as sensed by the sensor assembly 22.

Turning now to Figure 2, there is shown a package formed by the apparatus of Figure 1. The package - :91 2~J2~

comprises a core 31 which may be of the conventional type comprising merely a cylindrical body or it may be split axially in one or more locations (not shown) to facilitate removal and replacement on cable manufacturing machinery.
At 1:he start of the operation the tape ll is : attached by conventional means to one end of the core 31 and a number of turns is wound in spiral fashion to form an initial layer at a first position indicated at 32.

The number of turns is not fixed but may vary with the type, width and thickness of the tape and it should be understood that these turns overlap one another without any traversing taklng place. That is the carriage 12 is maintained stationary during the winding of the initial spiral wraps at the position 32.
After the desired number of turns is wound initially at the position 32, the carriage 12 i9 travers-ed by the servo-motor 27 rightwardly as shown by an axial distance equal to ~he width of the tape plus a small predetermined distance for clearance purposes. As the carriage 12 is traversed under the control of the con-troller 29 the tape flexes slightly to turn from the spiral form to lie at a small angle to the spiral forming a helix until it reaches the position shown at 33. At , ~

this position the controller 29 acts to halt the servo-motor 27 whereby the carriage 12 is maintained stationary and the tape is wrapped in spiral manner at the posi~ion 33 without any traverse taking place. The helical por-tion is indicated schematically at 321.
This process is repeated through positions 33 to 41 until ~he initial layers of end position 42 are placed and with cross over turn areas or helical portions between each position similar to the helical portion 321.
Each of the portions 34 through 41 have ~he same number of turns as position 33 and substantially hal the number of turns applied at the position 32. At the end position 42, the controller 29 acts to wrap effectively twice as many wraps as there are at the intermediate positions 33 through 41 and then acts to reverse the servo-motor 27.
The increased number of wraps at ~he end positions 32 and 42 are provided since it will be appreciated that each cycle of traverse acts to pass the end position only once while passing the intermediate posi~ions twice. The 2~ controller 29 then acts to traverse the carriage 12 in in~ermittent steps across each position 41 though 32 in reverse arrangement to the traverse in the opposite direction so as to wrap spiral sections at each of the positions with a helical traverse section between each.

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Figures 2 and 4 illustrate the package in a partially com~)leted state with a number of spiral steps added on top of the initial layers described above. For convenience of illustration the step height is exagger-ated. In Figure 4, the angular extent of each helical traverse section has been illustrated as 180 degrees although in practice it may include one full turn. In addition for convenience of illustration in Figure 2 the helical traverses have been distorted by reducing the angle for clarity. Positions 32, 33, 34 and 35 have been shown built up to a level of a next cycle with helical traverses from a position 32 to 33 and from 33 to 34 shown at 321 and 331 respectively. Helical traverses in the left to right direction are 421, 411, and 322 respec-tively.
The controller 29 is pre-programmed in depend-ence upon the width and thickness of the tape and the desired size of the package. Specifically the number of positions 32 through 42 can be adjusted and in practice this number can lie between 2 and 12 depending upon the end use of the package. In many circumstances the next machine can only receive relatively small packages where by packages of two spiral positions can be manufactured with three or four position packages also being possibly ~`~o~

used. On machines where size is not a limiting factor, up to twelve or even more spiral positions can be provid-ed .
The spacing between leach position and the nextis set by the controller 29 such that the spirals of one position do not overlap the spirals at another position but are spaced by a sufficiently small clearance that firstly the package is of a dense construction to contain the maximum material and secondly such that the spacing is less than the width of the tape to prevent ~ape collapsing into the position between two adjacent spirals.
The number of~urns, in each spiral at each position is in practlce dependent upon the thickness of the tape since if too great a step is formed this may inhibit the traverse of the tape from that position to the next. In practice the number of turns li~s in the range 5 to 1 complete turns for intermediate windings and between 2 and 10 complete turns for the end windings for tape lying in the range 5/lOOOOTH of an inch (.013mm) to 2/lOOOTH of an inch (.05mm) respectively. The number of turns at each posi~ion in any event is greater than one whole turn that is greater than 360 in order to lock the helical portion into the spiral at each position and at the end positions therefore at least 2 full turns is wrapped into each spiral winding.
The number of turns i.n each step in the package therefore ~ust be few or relatively small such that the tape is able to descend from the step in the helical traverse section while avoiding interfering with the normal or proper traverse of the tape and while avoiding forming substantial deformation or kinks in the tape. In addition a step of this height provides a frequency of helical traverse at each position which enables the helical t.raverses to inter-lock each position with another position throughout its radial height to provide the package with stability and resistance to collapse.
The time taken to traverse from one position to the next and hence the helix angle is controlled by the controller 29 such that it is less than the time spent stationary at each position. The time is set so that it is substantially the minimum possible while the traverse avoids forming kinks or substantial deformation in the tape and this time will vary dependent upon the flexibil-ity of the tape concerned. In practice the traverse takes about one half a turn of the pac]cage for tape 1/4"
wide (6.35mm) and of the order of one turn of the package for tape of 1/2" width (12.7mm)~
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The controller 29 is dependent upon the speed of rotation of the package and hence the period of time spent at each position in forming spiral turns also is dependent upon the speed of rotation of the package~ In this way as the package diameter increases the period of time increases to ~ai~tain the number of turns at each position substan~ially constant throughout the build of the package.
The number of spiral turns at the end positions 32 and 42 is 1ncreased relative to that at the intermed-iate positions so ~hat more than twice the number of turns is wrapped at the end positions. This increase is to compensate for the fact that the amount of material wrapped helically at the end positions is reduced because of the reduced traverses to that position. The number of turns wrapped spirally at the end positions is set to be other than a whole number so that the package is prevent-ed from being exactly symmetrical in its build. In this way patterning whereby one helical layer lies directly on top of the next hellcal layer is avoided since if this occurs it produces bumps in the package which can ser-iously deteriorate the package formation.
In other words each helieal traverse is angularly off-set from the preceding underlying traverse which is in turn off-set from the preceding underlying traverse. This off-set, in addition to avoiding pattern-ing, also acts to cause the helical traverses to inter-lock., as previously explained, each position to another position at the angulaxly ofi--set or angularly spaced positions. In this way it will be clear that each posi-tion is interlocked to its neighbor at ~paced or dis-persed positions throughout its radial and angular dimen-sion. This effect is best illustrated in Figure 4 which shows one end face of the package in which the steps, each of twice the height of steps at intermediate posi-tions, are indicated at 42A, 42B, 42C, 42D respectively.
Helical traverses in the left to right direction~ that is those from position 42 into positîon 41~ are shown in dash-dash lina for~ example at 421, 422 and 423 for the outermost and preceding underlying steps. Helical traverses from right~to left that is from position 41 into position 42 are shown as dotr-dash lines 424, 425 and 426. It will be noted that as the steps at the end ~20 position 42 are twice the height of the steps at the next adjacent position 41, the helical traverse 421 into the position 41 starts at the top of the step 42A and termin-ates at a height half way down the step 42A and the helical traverse 424 from the position 41 into the posi-i i ' ~

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tion 42 starts half way up the step 42A and falls to the bottom thereof, i.e. the top of the step 42B. Thus it will be seen that the helical traverses both in dot-dash and dash-dash ~ine act to inter-lock the position 42 tO
the position 41 throughout the radial and angular dimen-sion. Similar patterns will of course be observed between the remaining positions.
Turning now to Figure 3 the main frame lO and carriage 12 are substantially as shown in Figure 1 with the carriage 12 traversible relative to the guide 17 to move the winding position of the tape 11. In this embod-iment control of the traverse movement is effected by an electro-mechanical arrangement carried upon the carriage 12 and schematically indicated in the drawing. Specific-ally the control mechanism comprises a first countershaft 50 driven from the shaft 18 by a pair of chain wheels 51, 52 and a chaln 53 forming a chain drive. I~ will be appreciated that the chain drive could be replaced in this instance and in any other portion of the figure by a timing belt drive arrangement. The countershaft 50 is mounted in bearings 54 supported on the carriage 12 by a frame structure not sho~n but of conventional construc-tion which is readily apparent to one skilled in the art.

The countershaft 50 drives a first chain drive arrangement 55 and a second chain drive arrangement 56.
The chain drive arrangement 55 drives an air clutch 57 and in the reverse direction a chain wheel 58 mounted on a second countershaft 59. Thus the clutch 57 is driven in one direction and the chain wheel 58 in the opposite direction. The countershaft 59 is mounted in bearings 60 again carried on the carriage l2 an drives a second air clutch 61 though a further chain drive 62. Th~ clutches 57 and 61 are carried on a shaft 63 mounted in bearings 64 again mounted on the carriage 12. An air brake 65 is also carried on the shaft 63 and is attached to a portion of the carriage 12. It will be appreciated therefore that pneumatlc~ operatlon of the clutch 57 will act to : drive the shaft 63 in one direction; pneumatic oper~tion of the clutch 6l wilI act to drive the shaft 63 in the opposi~e direction; and pneumatic operation of the clutch/brake 65 wi11 act to brake the shaft 63. Pneumat-: ic control is arranged such that only one of the clutches 57, 61, 65 is operated at any one time.
The chain drive arrangement 56 drives a urther drive shaft S6 via a speed reduction gear 67. The shaft 6S is mounted in bearings 68 again supported by the carriage 12 and the shaft supports a control drum 69.

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The drum 69 therefore is driven via the shaft 66 and chain drive arrangement 56 from the package support shaf~
18 at a speed directly propor~ional thereto. The drum has around its periphery three "T" slots 70, 71, 72 which receive a plurality of dogs 73 which can be adjusted angularly around the drum to desired positions. The dogs 73 cooperate with limit switches 74, 75, 76 provided adjacent the drum cooperating with slots 70, 71, 72 respectively.
The limit switches 74, 75, 76 are connected to a central control device 77. The device 77 also receives input from limit switches 78, 79 supported upon the main frame 10 an adjustable relative thereto to define the end of the traverse of the carriage 12 so that at each end of its traverse the carriage 12 contacts on of the switches 78, 79 to inform the control device 77 that it has achieved that position.
Traverse of the carriage 12 is effected by a cylinder/piston ao mounted on the main frame lO with the piston rod attached to the wall 20 of the carriage 12.

Air supply to the piston is controlled by the control device 77 to respective ends of the cylinder/piston 80 so that extension and retraction of the pis~on within the cylinder acts to traverse the carriage 12. The speed ~nd distance of traverse is accurately controlled by a lead screw 81 carried in bearings 82 on the carriaye 12 and cooperating with a nut 83 connected to the carriage 12.
The lead screw 81 comprises an extension of the shaft 63.
The control device 77 comprises electrical relays and switches and three pneumat.ic control valves 84, 85, 86 all of which is indicated schematically since it comprises conventional devices arranged in a manner which will be apparent to one skilled in the art from the following description of the function thereof.
In operation during the build o~ a package with winding of the spiral at the position 34 just complete, a dog 73 in the slot 71 is positioned such that it contacts the limit switch 74 to inform the control device 77. The control device acts to operate the valve 86 to release the brake 65 and to operate the valve 84 which applies air to the cylinder/piston 80 at the let hand end there-of and activates the clutch 61. The cylinder/piston 80 thus applies force to the carriage 12 to move it to the right as shown under control of the lead screw 81 driven by the clutch 61. The amount and speed of movement is therefore accurately controlled by the clutch 61 and thence by the shaft 18 while the motor force is supplied , IL~
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from the cylinder/piston 80. After traversing a distance determined by the position of a dog 73 in the slot 71, the limit switch 75 is activated. The con~rol device 77 then operates the valve 86 to reactivate the bake 65 and the valve ~4 ~o close the pneumatic supply to the cylinder/piston 80 and to the clutch 61 whereby the traversing movement of the carriage 12 is halted. The carriage then remains halted to wind, as explained previously, a spiral of the tape a~ the position 35.
After a period of time dependent upon the posi-tion of a further dog 73 in the slot 70 and the speed of rotation of the drum 69 dependent upon the speed of the shaft 18, the Limit switch 74 is again activa~ed to release the braXe 65 and ~o traverse the carriage 12 to the right. The cycle of t~aversing and halting is con~
tinued from one end of the package to the other end as explained previously until the end position is reached whereat the limit switch 79 is activated by the carriage 12. The activation of the limit switch 79 is sensed by the control device 77 and acts to reverse the circuitry whereby the dog 73 in the slots 70 and 71 con~rol in a symmetrical manner to that explained previous the trav-erse to the left of carriage 12. However, the commence-ment of the leftward traverse is not commenced until the ~z~

limit switch 76 is operated by a dog 73 in the slot 72 which controls the number of turns spirally wrapped at the end position 36 in accordance with technical require-ments.
As described in relation to Figures 1 and 3, the apparatus c~sn be controlled either electronically or electro-magnetically. However these are only examples of a number of different ways in which the control can be provided.
Turning to the details of the drive to the traverse motion of the carriage 12, it will be appre-ciated that the roller 14 is driven at a rate dependent upon the supply of tape so as to maintain the tape under a constant predetermined tension. The package of tape is driven by frictional contact with the roller 14 which is substantially constant and hence the tension on the tape as it is wound onto the package is substantially constant provided that the load applied to the shaft 18 from the chain 53 is substantially constant.

In order to maintain the load substantially constant and relatively small, the motive force for moving the carriage 12 is completely supplied by the cylinder/piston 80 whereby the lead screw 81 acts to merely control the amount and speed of movement of the . , ~ .

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carriage 1~ substantially without the application of force thereto, For this reason the valves 84, 85 include regulators to control the application of force by the cylinder/piston 80 to the required amount. Thus the load on the shaft 1~l is limited to the substantially constant-ly driven shaft and control drum 69 and does not vary the tension of the tape as it i5 woundO
In an alternative arrangement, the package can be driven from the centre rather than from contact with its outer surace. In this case a slipping clutch is provided in the drive to allow ~he package to slow as it increases in diameter while maintaining constant the winding force or tension on the tape.
According to a yet further modifica~ion, it is possible to wind two or more tapes on the same core using the principles of the present invention. Generally the tapes will be overlapped as they are fed through the guide 17 and will be wound spirally at a plurality of positions spaced to that one spiral formed from over-lapped tapes does not overlap the next adjacent spiral.
Since various modifications can be made in my invention as hereinabove described, and many apparently widely differerlt embodiments of same made within the spirit and scope of the claims without departing from i'', ., lZOZ2B8 such spirit and scope, it is intended that all matter contained in ~he accompanying specification shall be interpreted as i.llustrative only and not in a limiting sense.

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Claims

1. A method of building a package of tape having a right circular cylindrical winding surface comprising forwarding the tape from a supply thereof, guiding the tape to a winding position on the core, rotating the core around its axis to wrap the tape around the core and traversing the winding position across the core to form the package, wherein the winding position is intermittently traversed to visit repeatedly during the package build each in turn of a pair of separate end positions spaced axially of the core and at each end position is maintained stationary for a period of time greater than two full turns of the core to wrap the tape spirally of the core so that the tape forms at a respective one of the end positions a right circular cylindrical step coaxial to the core of increased radial height relative to another position at which the radial height has not been increased, in between said each end position and said another position the tape forming a helical traverse portion, said step having a height such that the tape can descend to said another position with-out interfering with said traverse of the tape following which at said another position further wraps of the tape are applied to build the radial height thereof up to that of the step.
(2) A method according to Claim 1 wherein the step includes a number of turns of tape wrapped spirally lying in the range of about 2 to about 10.
(3) A method according to Claim 1 wherein said another position is arranged to be intermediate to said end portions and said winding portion is intermit-tently traversed to visit repeatedly said another posi-tion and is maintained stationary at said another posi-tion to wind tape spirally in at least one full turn, whereby said package is formed substantially from spirally wound positions.
(4) A method according to Claim 1, 2 or 3 wherein the helical traverse portion of the tape includes one full turn.
(5) A method according to Claim 1, 2 or 3 wherein each helical traverse portion is arranged such that it is angularly spaced from the next adjacent under-lying traverse portion.
(6) A method according to Claim 1, 2 or 3 wherein at each of said end positions the winding posi-tion is held stationary to wind the tape spirally of the core in a number of turns different from an integral number of turns whereby each helical traverse portion is angularly spaced from the next adjacent underlying traverse position.
(7) A method according to Claim 2 wherein said another position is arranged to be intermediate to said end portions and said winding portion is intermit-tently traversed to visit repeatedly said another posi-tion and is maintained stationary at said another posi-tion to wind tape spirally in at least one full turn, whereby said package is formed from spirally wound posi-tions.
(8) A method according to Claim 7 wherein each helical traverse position is arranged such that it is angularly spaced from the next adjacent underlying traverse portion.
(9) A method according to Claim 7 wherein at each of said end positions the winding portion is held stationary to wind the tape spirally of the core in a number of turns different from an integral number of turns whereby each helical traverse portion is angularly spaced from the next adjacent underlying traverse portion.
(10) A method according to Claim 1, 2 or 3 wherein said tape is forwarded from said supply at a constant speed and is wound while maintaining a uniform tension.
(11) Apparatus for building a package of tape having a right circular cylindrical winding surface wound on a core comprising a constant speed supply of the tape, support means for the core, drive means for rotating the core to wrap the tape therearound, guide means for guid-ing the tape onto the core at a winding position, traverse means for causing relative reciprocating move-ment between the guide means and the support means to traverse the winding position axially of the core to build a package, and traverse control means including traverse advance means arranged to intermittently advance the traverse means such that the winding position visits each of a pair of separate end positions of the package spaced axially of the core repeatedly during the package build and means for halting the traverse means for a period of time such that the winding position remains at each said end position in turn to wrap the tape spirally of the core at the position to form a step thereat of increased radial height relative to another position on the package, said step having at least two full turns and a height such that the winding position can traverse to said another portion to form a helical traverse portion of the tape which descends form said step to said another position without interfering with the traverse of the tape.
(12) Apparatus according to Claim 11 wherein the traverse control means includes means for adjusting the distance of advance of the traverse means between each position and the next adjacent position so as to adjust the spacing between the positions.
(13) Apparatus according to Claim 12 wherein the adjusting means is set such that the positions are spaced whereby the spiral of the tape at each position does not overlap the spiral of the tape at the next adjacent position.
(14) Apparatus according to Claim 12 or 13, wherein the adjusting means is set such that the posi-tions are spaced whereby the spiral of the tape at each position is spaced from the spiral of tape at the next adjacent position by a distance less than the width of the tape.
(15) Apparatus according to Claim 11, wherein the traverse control means includes means responsive to the speed of rotation of said drive means and for con-trolling the period of time in dependence thereon.
(16) Apparatus according to Claim 11, 12 or 15 wherein said drive means comprises a roller for contact-ing a peripheral surface of the package over a width thereof greater than the width of the tape.
(17) Apparatus according to Claim 11, 12 or 15 wherein said guide means comprises a roller arranged to contact the package whereby the tape passes around the roller in contact therewith until it engages the pack-age.