Web unwinding apparatus and method

An apparatus is illustrated for unwinding a web, such as cloth or paper, which utilizes a driven belt having a width in excess of the width of the web forming a cradle for a cloth roll and the like with adjusters for adjusting the path of travel of the belt including at least one oscillatable roll over which the belt passes and which is oscillated responsive to sensors sensing the position of the belt. A pair of downwardly and inwardly tapering guides are provided spaced opposite respective ends of a tubular core for maintaining proper position of the web roll carried thereby. A pair of downwardly and inwardly tapering guides are provided spaced opposite respective ends of a tubular core for maintaining proper position of the web roll carried thereby. The method contemplates doffing the core of the cloth roll by utilizing a vertically movable roll for tightening the belt while at the same time lowering one of a pair of spaced rolls supporting the cradle so.

BACKGROUND OF THE INVENTION 
Apparatuses for unwinding rolls of cloth supported between two rolls have 
been known as dewinders, and it is generally recognized that unwinding a 
roll of cloth in open width or at least with minimal folds so as to be 
considered in open width presents more problems than winding the cloth in 
the first instance. In the textile industry, it is often desirable to 
unwind rolls of cloth as for inspection or for further processing as in 
dyeing, or otherwise, finishing the cloth. The fabric tends to loosen in 
the outer layers causing the fabric to bunch up at the nip or contact 
point between the fabric roll and the driven roll or rolls. Similar 
problems are presented in the paper industry where rolls of paper are 
unwound. Other webs which are being unwound in open width present 
analogous problems. 
A center wind unwinder is illustrated in U.S. Pat. No. 3,900,063 while a 
surface unwinder utilizing a belt forming a cradle between two rolls for 
accommodating a cloth roll is illustrated in Austrian Patent No. 228,151 
of 1963. This Austrian Patent illustrates structure utilized in attempting 
to solve a belt tracking problem by utilizing endless V-shaped belt 
portions carried across the underside of the cradle forming belt with 
corresponding grooves in the rolls carrying the belt. It has been found, 
however, that such structures are ineffective in dealing with heavier 
cloth rolls which often weigh as much as 4,400 pounds and are 50 inches in 
diameter. An application of the belt and cradle arrangement to the paper 
industry is illustrated in U.S. Pat. No. 2,977,058. Other attempts to 
provide dewinders utilizing a cradle arrangement forming belt have 
included other uses of V-belts spaced longitudinally across the back of 
the cradle forming belt but such arrangements have been practical only 
with very light rolls and do not effectively solve the problem of guiding 
the cradle forming belt. 
Accordingly, it is an important object of this invention to provide a 
dewinder utilizing surface unwinder principles and a cradle forming belt 
extended between spaced level rolls which provide guide means for assuring 
proper tracking of the cradle forming belt together with effective means 
for doffing an empty core roll and placing a full roll of cloth and the 
like upon the cradle forming belt for unwinding. 
Another important object of the invention is to provide guide means for 
maintaining the tubular roll in proper transverse alignment upon the belt. 
SUMMARY OF THE INVENTION 
It has been found that effective guide means may be provided for assuring 
proper tracking of a cradle forming belt for use in a dewinder by 
positioning a guide roll beneath spaced level cradle supporting rolls. The 
guide roll is oscillatable to provide movement along its length changing 
the angle at which the belt is passed thereover for exerting a guiding 
force on the belt across its width. 
A method of dewinding includes the doffing of a core roll by tightening the 
cradle forming belt while at the same time lowering one of the spaced 
level rolls supporting cradle. While the belt supporting roll is lowered a 
new roll of web material may be passed thereover and placed between the 
belt supporting rolls and the belt loosened for forming a cradle. It is 
desirable that tightening and loosening of the belt be accomplished by 
utilizing a transverse roll which may be moved up and down by pneumatic 
cylinders located at each end so that the cylinders may act as shock 
absorbers when the newly web roll is placed upon the belt forming the 
cradle. 
When the core roll is doffed it rolls down over the lowered belt supporting 
roll and falls downwardly through a space between the lowered supporting 
roll and a cloth roll supporting table. When the full roll is placed on 
the belt a side abutment portion of the table is lowered bridging the 
space and permitting a full cloth roll, previously restrained thereby, to 
roll thereover on to the belt between the belt supporting rolls. 
An upright inwardly and downwardly tapering guide means is provided 
opposite each end of the tubular core for contact with the bottom of the 
tubular core in order to maintain proper transverse alignment. The guide 
means are movable in and out and are pivoted vertically by an upward 
movement on the pivotal arms which carry same out of the way during 
doffing and replacement with a full web roll.

DESCRIPTION OF A PREFERRED EMBODIMENT 
The drawings illustrate apparatus for unwinding a web from a web roll 
having a driven belt with a width in excess of the width of the web 
supported between a pair of spaced transverse upper belt supporting rolls 
forming a cradle for supporting the web rolls and for unwinding the web 
therefrom. At least one transverse aligned lower roll is provided for 
passage of the belt thereabout. A mounting A is provided for guiding an 
end of the lower roll for oscillatory movement in a predetermined path. 
Power operated means B move the end of the lower roll for oscillating 
movement in the predetermined path. Sensing means C are actuated by the 
belt for controlling the power operated means adjusting the position of 
the mounting for guiding the belt. A movable roll D is positioned beneath 
the spaced transverse belt supporting rolls in alignment therewith 
raisable and lowerable to tighten and to loosen the driven belt. A fluid 
operated cylinder E is provided for raising and lowering the movable roll. 
Means F are provided for lowering one of the spaced transverse upper rolls 
with respect to the other. Thus, placing of a full web roll on the belt 
may be facilitated by lowering said one of the spaced transverse rolls 
while tightening said belt against the force of the cylinder by moving the 
movable roll. 
One embodiment of the apparatus for unwinding a web in the form of cloth F 
from a roll 10 having a core 11 is illustrated in FIG. 1. While the 
invention is described in an embodiment suitable for use in unwinding 
cloth rolls, it is to be understood that the invention is useful with 
suitable apparatus for unwinding any other web material as in open width. 
The dewinder has a driven belt 12 which is supported between a front roll 
13 and a rearwardly spaced roll 14. The driven belt 12 has a width in 
excess of the width of the web F which is supported between the pair of 
spaced upper rolls 13 and 14 forming a cradle 15. The rolls 13 and 14 are 
preferably substantially level, forming a substantially horizontal run in 
the belt 12 carried between upper rolls 13 and 14. At least one transverse 
aligned lower roll 16 is provided with a mounting A for guiding an end of 
the roll for oscillatory movement in a predetermined path. The embodiment 
illustrated in FIG. 1 has two lower rolls 16 and 27. The alternate 
embodiment has only one lower roll 56 which is also provided with a 
pivotal mounting for oscillatory movement. 
Referring to FIG. 1, the mounting A includes a pivoted arm 17 which has 
fixed connection with a crank arm 18 through a fixed offset arm 19. A 
power operated extensible member 20 is actuated by a motor B. The 
operation of the motor B is controlled by sensors C which, in this 
instance, are operated on a go or no go basis responsive to passage of the 
edge of the belt 12 thereover. If the belt extends over the first or 
innermost of the sensors 21 and is operated within the neutral band 
between the sensors 21 and 22, then no movement of the roll is required or 
indicated. However, should the sensor 21 become uncovered then a signal 
resulting in movement of the belt to the right toward the neutral position 
is called for and likewise, covering of the sensor 22 calls for movement 
in the opposite direction. 
Oscillatory movement of the roll 16 is accomplished in an arcuate path 
illustrated by the arrow adjacent the crank arm 17 which carries the roll 
for rotation in a bearing 23. A self-aligning bearing supports a stub 
shaft 24 at the other end of the roll 16 and a fixed outer spherical 
housing 25 carries an inner face 26 therein which carries suitable 
anti-friction bearings for carrying the roll 16 for rotation. The belt 12 
is driven and supported by an additional transverse lower roll 27 which is 
driven by the motor 28 through a belt 29, see FIG. 3. The belt 12 is 
maintained in proper tension by the roll 30 which serves as a guide for 
the belt. The roll 30a together with the roll 27 supports the belt for 
tightening and loosening the belt 12 by raising and lowering the roll D by 
the fluid operated cylinder E. 
Instead of moving an oscillatable end of the roll in an arcuate path as 
shown if two rolls are used they may be skewed in respect to each other 
for guiding. Any other suitable roll guiding means for the belt may be 
employed where the guiding action may be effected along the length of the 
roll. The arcuate path illustrated requires the arcuate cut out 31a in the 
adjacent frame member. 
The rolls described above are carried for rotation within side frame 
members 31 and 32 and the fabric F is fed from the roll 10 over a roll 33 
and thence between rolls 34 and 35 preparatory to being fed into an 
inspection machine broadly designated at 36. 
In FIGS. 1, 3, 4 and 5, roll D is movable up and down in order to tighten 
and loosen the belt 12. This is accomplished through the use of a cylinder 
E which may be fixed to the frame members 31 and 32. 
A table has a rearward support area 37 which carries a tiltable gate or 
bridging member 38 at its forward edge to serve as an abutment to restrain 
a full cloth roll in position on the table against the tendency for the 
cloth roll to roll toward the dewinder. The gate has interleaved portions 
39 which carry upturned ends 40 for restraining a cloth roll 41. The gate 
38 is normally raised as shown in FIG. 3 to support a cloth roll but is 
lowerable by actuation of the pneumatic cylinder 42 to lower the gate 38 
about the pivot 43. When this has been accomplished the core roll 11 rolls 
downwardly as in FIG. 4 where it is caught by elongated longitudinally 
members 44 preparatory to lowering of the gate 38 to the position shown in 
FIG. 5. When the cloth roll has been rolled onto the belt 12, the roll D 
is lowered against the force of the cylinder onto the substantially 
horizontal run in the belt thereby forming the cradle 15. 
FIG. 3 illustrates the apparatus in running position with cloth F being 
unwound and fit to the inspection machine 36. The full roll 41 is 
restrained by the upturned ends 40. FIG. 3 illustrates doffing of the core 
11. This is accomplished by tightening the cradle forming belt 12 as 
described above and lowering the roll 14 by the action of the cylinder 45 
upon the bell crank arms 46 which are pivoted on the frames 31 and 32 at 
47. In FIG. 4 the upturned ends 40 are lowered and the cloth roll 41 
received upon the gate or bridge 38. In FIG. 5 the cloth roll 41 has 
passed over the bridge 38, over the lowered roll 14 and acts against the 
cushioning force of the cylinder E to form a cradle for unwinding the 
cloth roll. 
Operation 
The photocell 21 is light operated as illustrated in FIG. 6. When belt 12 
moves out of the light beam, the relay CR-1 contacts close and pickup a 
mercury relay CR-1A. This starts the motor B which will operate until the 
arm 17 contacts limit switch LS-3 or belt moves back into the light beam. 
As long as the photocell 21 sees light, the arm 17 will stay in the 
extreme travel direction and hold the switch LS-3 open. When the belt 
moves back into beam, the control relay CR-1 drops out which now disables 
the mercury relay CR-1A. Since the arm 17 has moved out of the center, it 
has also closed the limit switch LS-2 which is the in position for 
effecting center control. This limit switch will operate control relay 
CR-2 which controls the mercury relay CR-2A. Due to normally closed 
interlocks across both control relays CR-1 and CR-2 only one relay may be 
energized at any time. The limit switch LS-2 will pick up the relay CR-2 
and mercury relay CR-2A and reverse the motor B. The arm will move until 
the limit switch LS-2 opens which drops out relays CR-2 and CR-2A. The arm 
17 has now returned to center position. The photocell 22 is dark operated. 
Should the belt 12 move into and break the beam of the photocell 21, it 
would operate the relays CR-2 and CR-2A. As the arm 17 moves to the out 
position it also closes the limit switch LS-1 (out position to center). 
The operation is thus the same as outlined above. If desired, additional 
sensors 22a may be provided on each side of the belt in case of failure of 
the above system in order to prevent damage from extreme positions of the 
belt 12 resulting from misalignment thereof. 
The drive mechanism is a speed-torque drive and operates the same as that 
explained in U.S. Pat. No. 3,221,237. The transformer VT-1 controls speed 
of the motor B. The AUTO-MAN switch SS-1 enables fully automatic control 
of belt guiding or such may be placed in manual position and controlled 
from switch SS-4 in-out. 
Thus, proper tracking of the belt 12 is assured by moving a guide roll over 
which the belt passes along a predetermined path to vary the angular 
relationship between the guide roll and the belt responsive to a signal 
indicative of the movement required to correct any misalignment. The guide 
roll is moved along a predetermined path to vary such angular relationship 
and returned along that path after positioning of the belt. 
In FIGS. 2, 7, 8 and 9 the lower roll 56 is laterally oscillatable about a 
pivot 56a which may be located midway of the length of the roll. The 
tracking of the belt 52 is controlled through oscillation of the roll 56 
responsive to the linear actuator E which is pivotally connected as at 56b 
to the longitudinal frame 56c within which the roll 56 is mounted for 
rotation. The linear actuator is pivoted as at 56d opposite pivot 56b to 
the machine frame. The frame 56c is pivoted about the pivot point 56a, 
skewing the roll horizontally. Skewing of the roll 56 as thus described 
causes the belt 52 to move longitudinally along the rolls 53 and 54 as 
required for exerting a guiding action upon said belt in such a path as to 
exert a force similar to that tending to stretch the belt substantially 
equal at each edge thereof. The rolls 54 and 53 are driven by the belt 
54a. The lower roll 56 is mounted beneath and midway between the upper 
rolls 53 and 54 and is oscillated in a linear horizontal path. The guide 
rolls 16 and 56 should be positioned to have a belt wrap of less than 
180.degree. since more tends to reduce its effectiveness in guiding. 
A guide is illustrated in FIGS. 7, 8 and 9 which include a pair of upright 
core engaging members 60 spaced to accommodate the full length of a core 
61 as illustrated in FIG. 9 therebetween. The upright core engaging 
members 60 thus engage only a lower edge of the tubular core 61 so as to 
prevent the end from walking or becoming cocked out of transverse 
alignment. It should be noted, however, that adequate spacing between 
members 60 avoid all contact with the core 61 except when the core moves 
too far to one side or the other and then contact only takes place on one 
side and at the bottom of the core. 
Means are provided for carrying each of the upright core engaging members 
for movement in and out for engagement with a respective end of the core 
and include a transverse rod 62 which is pivotally mounted at one end at 
63 as shown in FIG. 8. The core guides 60 are carried upon a slide member 
64 which is slidable upon the bar 62 responsive to an extensible member 
such as the cylinder 65. The cylinder 65 is pivotally mounted on one end 
as at 66 upon an adjustable mounting 67 which may be adjusted to 
accommodate a web of any given width. The piston rod 68 has pivotal 
connection as at 69 upon the slide 64. An arm 70 connects the slide 64 and 
serves as a part of the mounting supporting the upright guide members 60. 
The means raising the guide members out of the way includes an extensible 
member including a cylinder 71 which is pivoted on one end as at 72 to a 
fixed member. The end of the extensible piston rod is pivoted as at 73 to 
a link 74 which raises the arm 70 above at a pivot point 63 moving the 
core guide out of the way. 
If desired, the core guides may simply be moved laterally outwardly 
sufficiently to accommodate doffing and replacement of the web rolls. As 
illustrated by the phantom lines at the right-hand portion of FIG. 8, 
during the doffing operation, the belt carrying rolls are pivoted 
outwardly and downwardly in order to tighten the belt and accommodate the 
used core being removed and the full web roll being moved into position. 
The upper roll 709 may be carried by a link 71 and pivoted downwardly to 
tighten the belt 52 to facilitate doffing responsive to the cylinder 73. 
The driven roll 74 is in fixed position. 
While a preferred embodiment of the invention has been described using 
specific terms, such description is for illustrative purposes only, and it 
is to be understood that changes and variations may be made without 
departing from the spirit or scope of the following claims.