Note: Descriptions are shown in the official language in which they were submitted.
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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
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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.
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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
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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
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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
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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
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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-
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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
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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
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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
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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
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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-
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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.
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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
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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
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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
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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
- 27 -
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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