Note: Descriptions are shown in the official language in which they were submitted.
- 21 9701 6
Apparatus and Method for Reelin~ a Web
Field of Invention
This invention relates generally to devices for reeling a web onto a cylinder, and more
particularly for detecting the presence of a web about a cylinder for d~ linillg timing and
motion of reeling equipment. Most specifically, the invention concerns the process of
termin~ting accumulation of a web on a first spool, and commencing ~ccum~l~tion of a web on
a second spool while the web continues to be delivered to the reel forming apparatus at a
constant rate, and a device for detecting when the web has engaged the second spool.
Back~round of the Invention
A recurrent problem in the paper making industry, and other industries having similar
processes, has concerned the reeling of paper onto spools as the paper leaves the paper making
machine. As it is difficult and expensive to stop the paper making machine merely to change a
take up spool, a system is required to terminate the accumulation of paper on one spool and to
commence accumulation on another spool while newly made paper continues to be delivered
from the paper making machine at a relatively constant speed. This process of cutting and
transferring a web to a new reel is called a turn-up.
Once a web has been cut, the cut end is not necessarily prone to feed onto the new spool
without wrinkles. The wrinkled portion of the web collected on the spool is generally unusable,
and so becomes waste. One way to reduce the amount of wrinkling is to bend the web about a
drum and to move the new reel away from the twelve o'clock position as quickly as possible.
Since the web of paper will continue to stream out of the paper machine at high speed it
is important to determine as quickly as possible whether the web has failed to engage the new
spool plope-ly. If so, the new spool must be moved out of the way as quickly as possible and
another effort at starting a new spool must be made.
2 2197016
It is also advantageous in the operation of paper reeling machinery to make sure that a
spool moved about a drum to a better position for reeling without wrinkles will find applopliate
machinery waiting to receive it.
S At present an operator watches to determine when each spool is full, that is, when it has
reached a specific diameter, when to lower the next spool against the top of the drum, and when
enough of the web has collected on the new spool that it can safely be moved about the drum.
Notwithst~n(ling experience, an operator's eye is a relatively imprecise measuring instrument,
and the timing and accuracy of the operation varies from operator to operator. It would be
preferable to have a device and method for ascertaining when the web has engaged the spool
suff1ciently, and for controlling the movement of the various elements of the process.
It is not uncommon for patches of unusable web to be delivered to the output reel. An
operator may, again, have difficulty e~tim~ting the amount by which the diameter of a parent
reel should be increased to allow for defective portions of the web, since too little allowance
will yield insufficient good web to yield the amount desired, and too great an allowance will
yield a wasteful amount beyond the amount of good web desired on the reel.
There is therefore a need for an improved system for controlling the turn-up of a
continuous web onto a spool.
Disclosure of Invention
The present invention relates to a means for determining whether a web is present about
a spool. In a first aspect of the invention there is an apparatus for sensing the presence of a web
about a spool, that apparatus comprising a structural member for mounting to a support structure
for deployment of the apparatus adjacent the spool; a sensing means mounted to the structural
member having sensing means alterable from a first output state when sensing a bare spool to a
second output state when sensing a web on the spool; and means for communicating the output
states to a signal processing device.
- 21 9701 6
In a further aspect of the invention, the apparatus includes distance measuring means
for m~uring the circumferential distance turned by the spool. In still another aspect of the
invention the sensing means is of a type chosen from at least one of the group consisting of: a)
an electrical resistance measurement circuit; b) a proximity sensor; c) a photoelectric sensor;
S and d) a digital camera. In still yet another aspect of the invention the apparatus has first and
second followers mounted to the structural member for riding upon the surface of one of (a) the
spool; and (b) a web covering the spool.
In another aspect of the invention there is a system for controlling the turn-up of a paper
10 reeling machine, that paper reeling machine having a) a drum against which to turn a continuous
moving web; b) first means for urging a first reeling spool toward the drum to squeeze the web
therebetween; c) second means for moving the spool about the drum from a first position to a
second position; d) third means for receiving the spool from the second means and for ret~ining
the spool during reeling of the web thereupon; and e) fourth means for cutting the web upstream
15 of a spool in said first position, and for encouraging the leading edge of the cut web to wind
about the spool; that system having a structural member for mounting to a support structure
adjacent to the spool; a sensing means mounted to the structural member having sensing means
alterable from a first output state when sensing a bare spool to a second output state when
sensing a web on the spool; and means for collllllunicating the output states to a signal
20 processing device.
A still further aspect of the invention includes a method of controlling the turn-up of a
continuous web onto a spool, that method comprising the steps of: positioning a new spool
above a continuously moving web at a location where that web is being bent about a partial arc
25 of a drum; positioning an apparatus for sensing the presence of a web about a spool in a position
for sensing the presence of a web about the spool, that app~dtus having a sensing means
alterable from a first output state when sensing a bare spool to a second output state when
sensing a web on the spool; and means for communicating said output states to a signal
processing device; cutting the web and causing the leading edge of the cut web to wrap around
30 the spool; sensing with said appal~lus for the presence of web about the spool monitoring the
output states of the sensing means with the signal processing device; and moving the spool
about the drum on hll~l~lel~lion by the processing device that the web is present about the
spool.
4 21 970t 6
Brief Description of Drawings
Figure 1 shows a general arrangement side view of an embodiment of web reeling
machinery according to the present invention.
Figure 2, being Figures 2a and 2b, shows side and front views of an apparatus for
sensing the presence of a web about a spool for use in the web reeling apparatus of Figure 1.
Figure 3, having first and second sheets, shows an algorithm for operating the web
reeling machine of Figure 1 with the apparatus shown in Figure 2.
Figure 4, being Figures 4a, 4b, 4c, 4d, 4e and 4f shows a series of views according to
the cyclic operation of the machine of Figure 1 according to the algorithm of Figure 3.
Best Mode for Carryin~ Out the Invention
In the description which follows, like parts are marked throughout the specification and
the drawings with the same respective reference numerals. The drawings are not necessarily to
scale and in some instances pr~ollions may have been exaggerated in order more clearly to
depict certain features of the invention.
The output end of a paper machine is shown generally in Figure 1 as 20. A nearly full
spool, or parent reel, is indicated as 22, a waiting empty spool is illustrated as 24, and a driven
drum is indicated as 26. A continuous web 28 leaves paper machine 20 at a constant speed,
several hundreds of feet per minute, in the direction of arrow 'A'. Initially empty spool 24 waits
clear of web 28. Most commonly, spools such as item 24 are 20 inch diameter steel cylinders
weighing roughly 1800 lb., having a central shaft extending axially from both ends thereof, each
shaft end having a bearing mounted thereto suitable to be grasped by a spool holding device
such that the bearing is held and the cylinder is free to revolve about the axis of the shaft. Spools
need not always be made of steel, and may have, for example, a rubber or other elastomeric
surface in some cases. A spool starter drive apparatus, shown generally as 30, is used to cause
spool 24 to spin at a speed approximating the speed at which web 28 is moving. Once the
previous, or parent reel, has reached the calculated desired reel size, measured by length of web
( SPEC LENGTH) or reel tli~m~ter (SPEC DL~METER), spool 24 is lowered to contact web
28, in what, although not precisely vertical, may for convenience nonetheless be termed the
twelve o'clock position, or al2 . Very soon thereafter web 28 is cut by any of several known
means, between the last roll, a paper spreading roll 32 of paper machine 20 and drum 26. That
portion of web 28 downstream of the cut runs along drum 26 to collect on full spool 22, which
2197016
s
is then moved away for subsequent processing or use. That portion of web 28 upstream from the
cut begins to wind onto spool 24, encouraged by any one of several known means. Once spool
24 has begun to accum~ te web 28, it becomes the new parent reel, and is rotated about drum
26 to the position formerly occupied by spool 22, which, although not precisely horizontal, may
S for convenience nonetheless be referred to as the three o'clock position, or a3, and a new spool
34 is brought into position, ready to recommence the cycle when spool 24 has been filled.
The embodiment illustrated in Figure 1 will now be described in greater detail with
reference also to Figures 2, 3, and 4. A spool holding a~p~dlus in the nature of a pope reel is
shown generally as 36. It includes drum 26, and a pair of primary arms 38, one of the pair being
the visible side illustrated, the other, not visible in the illustrations, being a matching arm of
opposite hand at the far end of drum 26, which pivot about an axis of rotation 40 common to
drum 26, and, as shown in Figure 4f, a driven gear 42. As shown in Figure 4a, primary arms 38
have an arcuate seat 44 for receiving the bearing surface of a spool, be it 24, 34 or some other.
15 As shown in Figure 4a, seat 44 is disposed between a grasping mechanism in the form of a
slidingly retractable tongue 46, the sliding direction being vertical in Figure 4a, and a co-
operable opposed claw 48 pivotally movable about a pivot 50 from an open position in which a
new spool may be introduced into seat 44; and a closed position in which a finger 52 urges a
spool, such as spool 24, to remain within the grasp of primary arms 38. The movement of claw
20 48 to the open position described also causes a movable stop 54 to move about pivot 50 to a
position in which a spool located between tongue 46 and claw 48 at al2 is compelled to sit clear
of web 28 and drum 26. A clearance of 3/8 inches has been found satisfactory.
Primary arms 38 are movable about axis 40 from a first position for receiving a spool, at
25 al2, to a second position, or a3 for delivering that spool to a pair of secondary arms 56 which
co-operate with a pair of ways 58 along which a filled roll is removed, as will be described
below. As with primary arms 38, only one of secondary arms 56 is shown, the other being of
opposite hand and not visible in the illustrations. The motion of primary arms 38 about axis 40
is controlled by an electric motor and gear drive system of conventional construction not visible
30 in the illustrations The sliding motion of tongue 46 and the pivoting motion of claw 48 are
driven by pneumatic cylinders of conventional construction and operation, also not visible in the
illustrations. A feature of such a pneumatic system during movement from al2 to a3 that as
web 28 ~ccumul~tes about spool 24 pneumatic pressure, acting through the medium of finger 52
of claw 48, constantly urges spool 24 toward drum 26. Also, as the number of layers of web 28
35 about spool 24 increases, that increase in ~i~m( ter of the reel forces spool 24 ouLw~dly from
seat 44. This motion compels finger 52 to deflect incrementally counter-clockwise about pivot
21 ~701 6
50. Despite this deflection, pneumatic pressure continues to act through finger 52 to urge against
spool 24 against drum 26.
As indicated in Figure 4b et seq., secondary arms 56 each have the form of a yoke 60
mounted on a shaft 62 extending radially outward from an axle 64 about which secondary arms
56 may pivot. A double acting pneumatic cylinder 66 is used to urge secondary arms 56
forward, or clockwise, about axle 64 to an extended position, and backward, or counter-
clockwise, thereabout to a home, or return, position. Cylinder 66 is connected to a pressurized
air supply and valve system permitting supply of 90 p.s.i.g. in the forward directions, and 30 or
90 p.s.i.g. in the rearward direction. Each leg 68 or 70 of yoke 60 termin~tt-s in a toe 72 or 74
respectively, each having a roller 76 or 78 mounted thereto. Yoke 60 is of a radius of curvature
to allow generous entry of spool 24 therein between rollers 76 and 78, and of such a size that the
weight of each full parent reel is carried by ways 58.
In operation, secondary arms 56 are positioned in the first, or home position, to receive a
spool, such as spool 24 as it moves to a3 in the grasp of primary arms 38. The thickness of web
28 collected on spool 24 as it arrives at a3 is not, in general, constant from spool to spool, but
varies according to the thickness of stock produced by paper machine 20, and the number of
turns ~cllmul~tçcl before reaching a3. Yoke 60 accommodates this variation. As web 28 builds
about spool 24, finger 52 deflects, and eventually spool 24 engages roller 78. At this point
backward pressure in cylinder 66 works to urge spool 24 against drum 26 and claw 48 can be
released and returned to its open position. Similarly, tongue 46 may be retracted to facilitate
return of primary arms 38 to al2 to await a sllçcee~ing spool.
The position of secondary arms 56 may be measured in many ways, whether by angular
position about axle 64 or by linear measurement on ways 58. In the embodiment illustrated the
position of secondary arms 56 is deterrnined by linear measurement using a Magnerule Plus
(T.M.) a magnetic induction sensitive position sensor indicated as 80. A discrete measuring
system, or a system of mechanical stops and relays could also be used, as could other forms of
continuous distance measurement.
Spool starter drive appaldlus 30, includes a motor of conventional nature, not visible in
the illustrations, connected to driven wheel 82 mounted at the depending e~ elluly of an arm
84, itself pivotally mounted to a support structure 86. Double acting pneumatic cylinder 88
extends from structure 86 to arm 84 such that provision of pressurized air to one side or the
other of cylinder 88 will bias driven wheel 82 against or away from spool 24. A motor control
- 21 9701 6
(not shown) is used to adjust the speed of the motor, and hence driven wheel 82 to cause a spool
to revolve at a rate for matching the linear speed of web 28.
A web cutting device is indicated as 90. In the illustrated embodiment this device is a
S Sandar Industries Inc., TUSA IV (T.M.) web cutter using a cutting tape in the manner set forth
in laid open C~n~ n Patent Application 2,046,605. Other web cutters are known in the art.
Finally, an appaldlus for sensing the presence of the web about the new reel is indicated
generally as 92. In the embodiment illustrated it includes an arm 94 movably extending from a
support 96, and a sensor carriage 98 loosely mounted to the distal end of arm 94. As before, a
pneumatic cylinder 100 is provided to urge carriage 98 against or away from spool 24 as may be
desired. Apparatus 92 is shown in Figure 1 contacting spool 24 on a slant, for ease of
illustration. In the preferred embodiment it swings downwardly and outwardly from support 96
to ride on top of spool 24 at roughly the 12 o'clock position.
Carriage 98 is shown most fully in Figures 2a and 2b. Carriage 98 includes a frame or
body 102 to which are mounted a leading spool follower in the nature of a steel roller bearing
indicated as a first roller 104 and a trailing spool follower in the nature of another steel roller
bearing indicated as second roller 106. Body 102 has a relieved arcuate face 108, the better to
accommodate the curvature of a spool, such as spool 24, and an outwardly extending dorsal
member, or spine 110 having a through hole 112 located more or less centrally therein to permit
attachment to arm 94. Rollers 104 and 106 are mounted within body 102 such that their rolling
~ surfaces 114 and 116 stand proud of arcuate face 108 for contacting a spool, and are each in
electrical contact with a lead wire, 118 or 120 respectively, in turn suitable for connection to an
electrical resistance sensing device and signal processing appald~us of a conventional nature,
indicated schematically as 122. When placed in contact with a bare steel spool the electrical
resistance registered between rollers 104 and 106 will be negligible. However, when a web of
paper or other less conductive material is present electrical resistance therebetween will be
significantly increased. It will be appreciated that other devices, such as brushes or sliding
electrical contact shoes or similar devices could be substituted for rollers 104 and 106 without
altering this function.
In the version of TUSA IV (T.M.) web cutter employed, the tear begins at one side and
works in a spiral to the other side. In another type of web cutter a tear is initiated near the centre
line of web 28 which eventually works its way on a curve to the outer edges of the web. In either
case a~pald~us 92 is preferably placed at a location near the edge of web 28 where the last part
21 970~ 6
of the tear will occur. thus it will also be at the last location at which the new web will begin to
turn up.
It may be noted that a non-contacting sensor, such as a suitably positioned, rigidly
mounted digital camera capable of differentiating between a bare metal, or bare rubber, surface
and a paper or textile web surface may also be suitable for the present purposes, and could be
augmented by optical timing marks or other similar means for detern~inin~ the cumulative
angular displacement of spool 24. Such a camera need not ride on spool 24 but could be
positioned in fixed spaced relationship therefrom at a desired orientation and distance for
observing spool 24 while not obstructing the spool ch~nging process.
A second device for sensing the presence of a web, in the nature of a proximity sensor is
shown as 124, mounted within body 102 and having a probe 126 extending therefrom proud of
arcuate face 108 for suspension in close proximity to the surface of a spool when rollers 104 and
106 are riding thereupon. It will be noted that sensor 124 whether it is a reluctance or
capacitance or similarly based electrical properties sensor, is sensitive to the distance of
separation between probe 126 and the more or less monolithic steel structure of spool 24 and the
reading obtained therefrom will vary significantly as each successive layer of web 28 is
introduced therebetween. In the prefered embodiment a reluctance sensor is used. As above, the
output signal from sensor 124 is colllmullicated by wire 128 to signal processing device 122.
A third sensing device in the nature of a counter is shown as 130. Roller 104 is provided
with a partial rebate or groove 132 extending through a partial arc of the chculllrelcllce, that
partial arc being 180 degrees. Each revolution of roller 104 will generate an alternating signal in
counter 130, collllllunicated via wire 134 to signal processing device 122, such that the distance
traveled along a contact surface may be computed, the rate of alternation also providing a
measure of the speed spool 24, and subsequently of web 28.
A fourth sensor in the nature of an optical sensor 136 is shown mounted to body 102 and
has an objective 138 extending proud of face 108 for observing spool 24. An output signal is
coll"llullicated to signal processing device 122 by means of wire 140.
Also shown in Figure 1 are a reel calendar web speed measuring device 142 and a web
OFF SPEC defect indicating device 144, each providing an output signal to signal processing
device 122.
- 21 970~ 6
The operational sequence for achieving a web turn-up onto a new spool will now be
described with reference to the sequence of illustrations of Figures 4b through 4f, following the
logical sequence set out in Figure 3. In Figure 4b parent reel 22 is nearing its full size. New
spool 24 has just been lowered into primary arms 38 at the twelve o'clock position and claw 48
S is in its open position such that spool 24 is held on stop 54, clear of web 28 and drum 26. Spool
24 is not revolving. Apparatus 92 and driven wheel 82 are both held clear of spool 24. Cylinder
66 is provided with sufficient pressure to urge secondary arms 56 in the backward direction,
in a position in which the signal from position locating device 80 to signal processing device
122 is interpreted as ~x- An operator has selected automatic operation, or AUTO mode.
Signal processing device 122 continuously monitors ~x to compare it with a set point
turn-up value ~iF (i.e., parent reel full). ~F is not necessarily a constant value, but is calculated
for each successive reel on the basis of a desired quantity of good web plus an adjustment for
any amount of web COIlt~illillg defects detected by OFF SPEC defect indicating device 144 at
the web speed '~)w indicated by web speed measuring device 142. A value for either ON SPEC
LENGTH or ON SPEC DL~METER parameters is calculated, and updated at real time, whence
a current value for ~F is determined according to the specific geometry of the machine.
At a time Tl, (~ x)/Vw equals a preset value of Xl seconds for the time rem:~ining
before a turn-up is due. At time Tl apparatus 92 and driven wheel 82 are brought into
engagement with spool 24. At time T2, similarly determined, signal proces~ing device 122
provides a signal to bring driven wheel 82 into engagement with spool 24 and, while monitoring
the output from counter 130, provides an ON/OFF output signal to the motor of spool starter
al)pal~lus 30 to cause driven wheel 82 to drive spool 24 at a cil~;ulllrt;rel.tial speed between ~w
and '~w plus a pre-selected dead-band value, ~, by a time X2 seconds before a turn-up is due. At
time T3, X3 seconds before a turn-up is due, the pressure in cylinder 66 is reduced to
LOADING pressure, a reduced pressure, such as 30 p.s.i.g., in the backward direction. This is
the state illustrated in Figure 4b.
At time T4 the turn-up is initiated as driven wheel 82 is disengaged from spool 24, claw
48 is moved to its closed position thus lowering stop 52 and permitting spool 24 to engage drum
26 at ~ x . After a 750 ms wait the web cutting device is energized, in the specific
embodiment illustrated the TUSA IV (T.M.) cutter advances the sticky end of its tape into the
nip between spool 24 and drum 26. As soon as the tape is pinched between web 28 and spool 24
it begins to wind in a spiral thereabout, cutting web 28 as it does so, and compelling that portion
of web 28 upstream from the cut location also to wrap around spool 24. The remainder of web
28 downstream from the cut location continues along drum 26 to accumulated on parent reel n.
- 21 ~701 6
Signal processing device 122 monitors the resistance between rollers 104 and 106 and
the proximity of sensor 124, and the photoelectric output of sensor 136, to determine whether
there has been a change in electrical conductivity or a change in proximity or detection which
5 would indicate the presence of web 28 about spool 24. From the time that such a signal is
received processing device 122 monitors the signal from counter 130 while coll~inuillg to test
for the presence of web 28. In the preferred embodiment the test for a successful turn-up is
whether web 28 is present after two full revolutions of spool 24. Not all of the sensors need be
provided, but additional sensors permit more versatile use of a single apparatus for more than
10 one type of spool, and may also provide a measure of verification for each other.
If the test for the presence of web 28 fails after two full revolutions then signal
processing device 122 provides a signal to cause claw 48 to return to the open position, in which
stop 54 once again raises spool 24 clear of drum 26, causes a warning signal to alert an operator,
15 and termin~tes automatic operation by transferring the entire system to manual control.
If the test is successful, then signal processing device 122 initiates operation of the
primary arm motor to cause the primary arms 38 to leave the twelve o'clock position and move
toward the three o'clock position. It is advantageous to do this at an early opportunity since
20 forcing web 28 to traverse a greater distance along an arc of drum 26 before winding on spool
24 will tend to discourage, if not rapidly elimin~te, wrinkling. During this movement pneumatic
pressure acting through finger 52 urges spool 24 toward drum 26, encouraging formation of a
taut reel. Once a successful turn-up has been achieved a~p~dLus 98 is also withdrawn to an
inactive position.
As primary arms 38 rotate about axis 40 carrying spool 24 they soon approach a critical
angle, aCF~ffCa~ which defines the angle beyond which the motor driving the motion of primary
arms 38 is incapable of stopping and returning spool 24 to the twelve o'clock position. Before
primary arms 38 move past aCr~tica~ and complete the motion to a3 it is necessary to determine
30 whether secondary arms 56 will be in an a~plop.iate position for receiving the new reel, spool
24, when it arrives. A number of steps must have occurred to satisfy that condition.
When web 28 is cut at ~ F the reduced, loading pressure, such as 30 p.s.i.g., isreleased from the backward direction of cylinder 66 and an high ejecting pressure, such as 90
35 p.s.i.g. in the forward direction is applied to urge secondary arms 56 to move in a clockwise
direction, that is, away from pope drum 26. This pressure will force parent reel 22 outwardly in
the direction of arrow 'B' along ways 58 to a position from which it may be moved elsewhere
- 11 21 9701 6
for further proces~ing. During this motion signal processing device 1~ monitors the Magnerule
Plus (T.M.) output to ensure that both arms of secondary arms 56 move synchronously, it being
advantageous to avoid ejecting a full reel, weighing perhaps lS tons, at a skewed angle.
Figure 4c shows uppermost roller 76 at the point at which it no can longer exert a force
against parent reel 22. Roller 78 is shy of the uppermost surface of ways 58. and cannot impede
the ejection of parent reel 22 which is thus released from yoke 60. In this position measuring
sensor 80 indicates ~E~ that is, full extension of secondary arms 56. Parent reel 22 has enough
momentum to continue rolling along ways 58 to reach a stop.
When signal processing device 120 finds that ~ E, it produces an output signal to
vent the pressure from the forward side of cylinder 66 and to apply high pressure, such as 90
p.s.i.g, to the rearward side of cylinder 66 to cause secondary arms 56 to return toward drum 26.
Having done this processing device 122 continues to monitor the output signal from measuring
sensor 80 and to test it against ~R, that is, a chosen location along ways 58 closer to drum 26
than ~E. When ~ R one may infer that secondary arms are returning toward ~H, a home, or
return position close to drum 26, and it is permissible to allow primary arms 38 to pass aCnacal
since it may also be inferred that the time required for the secondary arms 56 to travel from ~R
to ~H is less than the time for primary arms 38 to move from aCnaca~ to a3.
When ~ H secondary arms 56 cease motion and await the arrival of spool 24. When
a = a3, that is, when spool 24 enters yoke 60 and encounters ways 58, signal processing device
122 causes the primary arm motor to stop. Web 28 continues to build on spool 24, causing it
further to deflect finger 52. In due course spool 24 also begins to cause motion of secondary
arms 56 clockwise about axle 64. When ~ A the force required to m~int~in spool 24
against drum 26 is provided by cylinder 66 and the pneumatic force on finger 52 may be
released. Thus signal processing device 122 causes claw 48 to move to its open position,
releasing spool 24. To facilitate early return of primary arms 38 to a12 signal processing device
122 further causes slidable retraction of tongue 46 such that primary arms 38 may rotate counter
clockwise without lifting spool 24.
If tongue 46 does not retract then signal processing device 122 monitors the position of
secondary arms 56. When ~ B spool 24 is clear of the furthest possible extent of tongue 46
and signal processing device 122 activates the primary arm motor to return primary arms 38 to
al2 position if it has not already been done, without regard to the position of tongue 46. When
primary arms 38 reach the twelve o'clock position the turn-up sequence is complete. Tongue 46
may be extended once again awaiting commencement of the next turn-up cycle.
2197016
12
Various embodiments of the invention have now been described in detail. Since changes
in and or additions to the above-described best mode may be made without departing from the
nature, spirit or scope of the invention, the invention is not to be limited to those details, but
S only by the appended claims and their equivalents.
