U.S. patent number 3,780,961 [Application Number 05/143,059] was granted by the patent office on 1973-12-25 for controls for spooling apparatus.
This patent grant is currently assigned to Eastman Kodak Company. Invention is credited to Conrad J. Druzynski, John N. Gade, Ghassan N. Kahwati, James D. MacKay.
United States Patent |
3,780,961 |
Kahwati , et al. |
December 25, 1973 |
CONTROLS FOR SPOOLING APPARATUS
Abstract
A digital count is converted to an analog signal for application
to a servo for driving spooling apparatus. The duration during
which the spooling occurs is clocked. In the event the clocked
duration gets to be too long, or short, the reference for the
digital-to-analog converter is adjusted, respectively to increase
or decrease the input to the servo. At one point during spooling,
the count is gradually reduced (down-counting) to a certain level
corresponding to a low spooling speed. The duration for low speed
spooling is also clocked, and the time for starting down-counting
is regulated to keep constant the duration for low speed
spooling.
Inventors: |
Kahwati; Ghassan N. (Rochester,
NY), Gade; John N. (Rush, NY), MacKay; James D.
(Webster, NY), Druzynski; Conrad J. (Loveland, CO) |
Assignee: |
Eastman Kodak Company
(Rochester, NY)
|
Family
ID: |
22502418 |
Appl.
No.: |
05/143,059 |
Filed: |
May 13, 1971 |
Current U.S.
Class: |
242/534.2;
324/172; 242/413; 242/544 |
Current CPC
Class: |
B23D
36/0066 (20130101); G03C 3/00 (20130101) |
Current International
Class: |
B23D
36/00 (20060101); G03C 3/00 (20060101); B65h
025/22 () |
Field of
Search: |
;242/75.51,67.3
;226/33,43 ;324/172,161 ;318/480,484,461 ;250/219R,219LG,219S |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Mautz; George F.
Assistant Examiner: Jillions; John M.
Claims
What is claimed is:
1. Apparatus for controlling the spooling of a discrete length of
web material having indicia thereon for starting and stopping said
spooling comprising:
a. means upon which said spool of web material is formed,
b. servo means for driving said first-named means,
c. clocking means responsive to said indicia for timing the
duration of a spooling operation and generating a signal
representing said duration, said signal being utilized in a
succeeding spooling operation,
d. means for signalling that the said web material has a zero
velocity, indicating the completion of said spooling operation,
e. means responsive to said means for signalling for disabling said
clocking means,
f. means for providing a signal representing a reference duration,
indicating a desired nominal spooling duration,
g. means for comparing said reference duration signal and said
signal representing the clocked duration,
h. means for applying an input signal to said servo means, and
i. means responsive to the output of said comparing means for
varying the input signal to said servo means to keep constant the
duration for said succeeding spooling operation.
2. The apparatus of claim 1,
a. wherein said means for applying a signal to said servo means is
a digital-to-analog converter,
b. wherein said means for varying the input to said servo means is
means for providing a variable reference signal to said
digital-to-analog converter, and
c. wherein said apparatus includes means for applying a spooling
speed representative signal to said digital-to-analog
converter.
3. The apparatus of claim 1 wherein said means for comparing
comprises:
a. an up-down counter,
b. means for presetting said counter,
c. means for increasing and decreasing the count of said counter in
response to a clocked duration signal which may be, respectively,
greater or less than said duration reference signal, and
d. means cooperative with said up-down counter for increasing and
decreasing the input to said servo means when said up-down counter
respectively fills and empties.
4. The apparatus of claim 3 wherein said means for increasing and
decreasing the servo means input comprises:
a. a presettable up-down counter, the count of which is increased
and decreased in response to the filling and emptying of said
first-named up-down counter, and
b. a digital-to-analog converter cooperative with said second-named
up-down counter for providing said reference for said first-named
digital-to-analog converter.
5. The apparatus of claim 2,
a. wherein said means for applying a spooling speed representative
signal to said digital-to-analog converter is a presettable
down-counter, and
b. wherein said apparatus includes means responsive to said indicia
for starting and stopping said spooling for respectively presetting
and clearing said downcounter.
6. The apparatus of claim 5 including:
a. clock pulse producing means,
b. means responsive to said indicia for applying said clock pulses
to said down-counter after said counter has been preset and before
said counter has been cleared, and
c. means cooperative with said down-counter for ending the
application of clock pulses to said down-counter when the count of
said down-counter has dropped to a predetermined amount.
7. The apparatus of claim 6 including:
a. means for further varying said servo means input signal so that
said servo means may have a first high speed plateau and a second
low speed plateau,
b. means for clocking, and for producing a signal corresponding to,
the duration that said servo means runs at low speed,
c. means for producing a signal representing a low plateau
reference duration,
d. means for comparing said low plateau reference duration signal
with said clocked low plateau duration signal, and
e. means responsive to said last-named means, and cooperative with
said means for further varying said servo means input signal, for
adjusting the time for commencing the application of clock pulses
to said down counter, thereby to keep constant the duration of the
low speed plateau of a succeeding spooling operation.
8. Apparatus including spooling means for spooling a web having
indicia thereon that defines the starting and stopping of said
spooling, comprising:
a. servo means for driving said spooling means,
b. a signal source for applying a drive signal to said servo
means,
c. first and second signal-producing means responsive to said
indicia on said web for respectively applying and removing the
signal output of said signal source from said servo means,
d. detector means for producing a signal at the moment when said
spooling speed becomes zero,
e. means, cooperative with said first signal-producing means and
said detector means, for clocking the time difference between the
occurrence of signals from said first signal-producing means and
said detector means,
f. means for generating a difference signal representing said time
difference, and
g. means responsive to said difference signal and to a
predetermined reference duration signal for increasing the signal
output of said signal source in a succeeding spooling operation
when said time difference is more than said predetermined duration,
and for decreasing the signal output of said source when said time
difference is less than said predetermined duration.
9. The apparatus of claim 8 including:
a. third signal-producing means responsive to said indicia on said
web, after said first signal-producing means and before said second
signal-producing means produce their respective signals, for
reducing to a low plateau the output of said signal source,
b. means for clocking and for generating a signal corresponding to
the duration of said low plateau signal, and
c. means responsive to the low plateau clocked duration signal and
to a predetermined low plateau reference duration signal for
varying the occurrence of the signal output of said third
signal-producing means to keep constant the duration of the low
plateau signal of a succeeding spooling operation.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates in general to spooling machines and, in
particular, to improved apparatus for controlling the operation of
a spooling machine.
2. Description Relative to the Prior Art
Consider the high speed winding of small spools, say, of
photographic film and/or paper, the wound spools to be virtually
continuously fed to packaging equipment in a fully automated
system. The spools, from a customer-acceptance standpoint, must be
similarly wound; and such winding must be very carefully kept in
step with other packaging procedures for optimum efficiency.
A supply of film and/or paper is provided with appropriate indicia
such as markings, or notches or the like, which define discrete
lengths of film and/or paper to be wound into respective spools,
there being means for separating just-wound spools from the supply.
The markings, or notches or the like, are used to signal the start
and stop of the spooling procedure ... but the actual spooling
operation may be subject to various adverse influences. For
example, the input to the spooling drive may drift, causing the
spooling operation either to get ahead of, or behind, other
packaging procedures; or assuming, say, that the spooling drive is
hydraulic, the temperature or viscosity, etc, of the hydraulic
fluid may change, again causing the spooling operation to lead or
lag other packaging procedures.
SUMMARY OF THE INVENTION
To assure the in-step winding of successive similarly wound spools,
the invention proposes to clock the time it takes for notches (or
markings) to start and stop discrete spooling procedures and, when
the clocked duration is greater, or less, than a predetermined
time, or range of times (and which occurrences are hereinafter
sometimes called clock differentials), to increase or decrease,
respectively, the input to the spooling drive, thereby to keep the
winding duration, from spool-to-spool, the same.
In a presently preferred form of the invention, the increase, or
decrease, of the spooling drive input is effected by varying, in
accordance with clock differentials, the reference that is applied
to a digital-to-analog converter, the input to which is a count
representing a desired spooling speed, and the output of which is
applied to the spooling drive. By varying the reference for the
digital-to-analog converter, as indicated, the speed count is
effectively multiplied by a clock-duration variable, causing the
output of the digital-to-analog converter to be a variable that
maintains the spooling speed to keep constant the spooling
duration.
To avoid the problems of possibly having to adjust, up or down, the
reference for the digital-to-analog converter after each spooling
cycle, the invention further proposes to use as a reference for the
digital-to-analog converter, the analog equivalent of a (preset)
count that is increased and decreased respectively whenever a
preset up-down counter fills and empties in response to successive
clock-durations which are too long and too short. Therefore, so
long as the successive clock-durations remain within a
predetermined range of times, the up-down counter never fills or
empties and, attendantly, the reference for the digital-to-analog
converter remains invariant.
The braking of the spooling operation has a direct bearing on the
timing of other procedures associated with the spooling operation.
Apparatus according to the invention employs the prior art speed
profile depicted in United States Pat. No. 2.776,094 (FIG. 32),
assigned to the instant assignee, whereby high speed spooling is
first ordered, followed by a gradual lessening thereof to an
ordered low spooling speed, from which quick braking can be easily
effected. The invention proposes that the aforesaid count that is
representative of a desired spooling speed appear in and be
provided by a downcounter: A notch (or marking) in the paper or
film being spooled first causes a high count to be applied to the
downcounter for high speed spooling; thereafter, the notch causes
the application of down-countng pulses to the counter until a
low-speed spooling count is reached; and then, while spooling
continues at low speed, the notch causes the counter to be cleared,
thus causing the low spooling speed to drop quickly to zero.
As noted above, the timeliness of the spooling cycle, and the
braking thereof, has a direct bearing on other procedures. Given
controls for holding each spooling operation to a certain duration,
and means for abruptly braking the spooling operation, for sake of
efficiency, it is incumbent to keep the duration of low speed
spooling quite short. To this end, the invention further proposes
to control tightly the duration of low speed spooling, whereby
whenever the duration of low speed spooling is more or less than a
certain (short) amount, or range of amounts, the invention provides
means for shifting the time for switching from high speed to low
speed spooling, thereby to keep the duration of low speed spooling
constant.
OBJECT OF THE INVENTION
To assure efficient and timely spooling of discrete lengths of web
material .
The invention will be described with reference to the Figures,
wherein:
FIG. 1 is a schematic block diagram of apparatus embodying one
aspect of the invention,
FIG. 2 is a schematic block diagram of apparatus which, when used
in conjunction with apparatus indicated in FIG. 1, provides another
aspect of the invention,
FIG. 3 is a schematic block diagram of apparatus which, when used
in conjunction with apparatus indicated in FIG. 1, provides still
another aspect of the invention,
FIG. 4 illustrates a spooling speed profile provided by apparatus
as depicted in FIG. 3,
FIG. 5 is a schematic block diagram of apparatus which, when used
in conjunction with apparatus indicated in FIG. 3, provides still
another aspect of the invention, and
FIG. 6 illustrates a spooling speed profile according to the
teaching of FIG. 5.
Referring to FIG. 1, a web 10 has notches 12,14 which generally
define the length of web to be spooled by a spindle 16. The web 10
is fed into a pre-aligned slot in the spindle by means of pinch
rollers 20,22. The roller 22 is driven, and positioned to engage
the web 10, by a drive 24 which is energized by a flip-flop device
26 in response to actuation of a switch 28. As the lead end of the
web 10 enters the slot 18 (i.e., the web travels the distance d),
the notch 14 sees a photoelectric device PC-1, which disengages the
drive 24 via the flip-flop device 26, and turns on a flip-flop
device 30 to signal high speed spooling apparatus 32 into
operation. When the notch 14 sees a photoelectric device PC-3, the
flip-flop device 30 is turned off (spooling ended), after which a
knife 34 is actuated to cut away the just-wound spool, and thus
ready the spooling equipment for a next spooling operation. A web
supply loop 35 is provided for tensionless spooling of the web
10.
The knife drive and spindle slot alignment, as well as means for
providing the supply loop 35, form no part of the present
invention. And the function of a photoelectric device PC-2 will be
described later in connection with FIGS. 3 through 6.
As soon as the flip-flop device 30 is turned on by the
photoelectric device PC-1, a preset count is applied, via gates 36,
to a digital-to-analog converter 38, the output of which is applied
to actuate a spindle (16)-driving servo 40. The servo 40 may
include, as appropriate, a motor, amplifiers, feedback, etc.
Depending on the magnitude of a reference signal applied to the
digital-to-analog converter 38, the signal output of the
digital-to-analog converter 38 will, when the gates 36 are opened,
snap to a high signal plateau P for driving the servo 40 at high
speed. Digital-to-analog conversion techniques, as herein applied,
are well known; see, for example, "Digital Computer and Control
Engineering," McGraw-Hill Book Company, New York, N.Y., 1960, pages
742 through 744, Library of Congress Catalog Card No. 59-15055. In
response to its signal input, the servo 40 rapidly runs up to a
speed plateau Sp and, when the photoelectric device PC-3 sees the
notch 14, the servo input signal is cut to zero, causing the
spooling speed to coast down to a stop.
In accordance with the invention, the duration of spooling is
clocked: The photoelectric device PC-1, at the start of a spooling
peration, actuates a flip-flop device 44, so that clock pulses may
be applied via a gate 46 to a counter 47; as soon as the servo has
coasted to a stop, the output of a tachometer 48 disappears,
causing a signal comparator 50 to trigger the flip-flop device 44
to close the gate 46. Thus, the counter 47 registers a count
representing the duration that it takes, from start to finish, for
the spooling operation. So long as the clocked duration is within
certain limits (i.e., L > C > S), a preset up-down counter 51
applies its preset count to a digital-to-analog converter 52, the
output of which is the reference for the digital-to-analog
converter 38. Should the clocked duration exceed a preset certain
amount (L) -- which can happen as a result of a servo gain change,
and the like -- a comparator 54 produces, in response thereto, a
pulse to increase the count of the counter 51, whereby the
reference output of the digital-to-analog converter 52 will
increase to increase the input to, and speed of, the servo 40.
Similarly, in the event the clocked duration is less than a preset
certain amount (S), a comparator 56 produces a pulse to decrease
the reference for the digital-to-analog converter 38; which is to
say that the servo 40 input, and speed, decreases. Thus, the input
to and the speed of the servo 40 is regulated by the output of the
digital-to-analog converter 38, thereby to keep constant the
duration that it takes for each spooling operation.
The servo correction technique discussed above presupposes the
adjustment of the servo 40 input after each spooling operation. In
a preferred form of the invention, the circuit 60 is replaced by
the circuit of FIG. 2, whereby only after a "clocked duration
drift" of a given amount is the reference for the digital-to-analog
converter 38 changed: A preset count is gated (62) into an up-down
counter 64. After each spooling cycle, if the clocked duration is
more or less than a given amount, or range of amounts, the up-down
counter 64 is respectively increased or decreaed, say by one. Only
when the counter 64 fills, or empties, is the count of the
reference-changing counter 51 increased, or decreased; and so long
as the count of the counter 64 drifts up and down within its
fill-to-empty range of counts, the reference provided for the
digital-to-analog converter 38 remains invariant. In other words,
the technique of FIG. 2 obviates the need for continual servo speed
correction, and permits slight drift of the servo speed within a
prescribed tight range of speeds. An OR gate 66, operative with the
gates 62, re-applies the preset count to the up-down counter 64
each time the counter 51 is increased or decreased, thereby to
re-establish the reference count for the counter 64.
Rather than provide signal and spooling speed profiles for the
servo 40, as indicated in FIG. 1, apparatus according to the
invention preferably employs a (composite) signal-speed profile
like that indicated in FIG. 4: A large signal input is applied to
the servo 40 in response to a notch-produced signal from the
photoelectric device PC-1, causing the servo speed to run rapidly
(dashed line 70) to a high speed plateau; when the notch sees the
photoelectric device PC-2, the signal input to the servo 40 is cut
gradually to a low level, causing the servo speed to run down
gradually to a low speed plateau from which quick braking can be
easily effected; and when the photoelectric device PC-3 sees the
notch, the signal input to the servo is cut to zero, causing the
servo speed to drop extremely quickly to zero (dashed line 72).
To implement the signal-speed profile of FIG. 4, apparatus
according to the invention employs the circuit of FIG. 3 as a
substitute for the circuit 80 of FIG. 1: In response to the
notch-produced signal output of the photoelectric device PC-1, the
flip-flop device 30 gates (36') a high plateau preset count into a
down counter 82. At the instant the photoelectric device PC-2 sees
the notch, a flip-flop device 84 opens a gate 86 to allow clock
pulses to pour into the down counter 82, causing the count of the
counter 82 to reduce gradually to a low plateau count: the count of
the counter 82, as it counts down, is continually compared with a
preset count representing a desired low speed plateau; and at the
moment the compared counts are equal, a comparator 88 pulses the
flip-flop device 84 to close the gate 86. By applying the count of
the counter 82 to the digital-to-analog converter 38, the speed
profile of FIG. 4 obtains for the servo 40.
For optimum efficiency in the spooling operation, it is desired to
run at high speed as long as possible and, conversely, to run at
low speed for as short a time as possible: To this end, the
invention proposes the substitution of the circuit of FIG. 5 for
the circuit 90 of FIG. 3, whereby the duration of slow speed
running is clocked and kept within a prescribed range of short
times. To keep the duration of slow speed running within its
prescribed range, apparatus according to the inventon proposes the
effective shifting of the time for actuating down-counting from the
high speed plateau to the low speed plateau: a lengthened slow
speed duration calling for a double-delay in the start of
down-counting (thereby to extend the duration of high speed
spooling a bit); a desired, or aim, slow speed duration calling for
a single delay in the start of down-counting; and a shortened slow
speed duration calling for no delay in the start of down-counting
(thereby to shorten the time for high speed spooling at the expense
of a lengthened period for slow speed spooling).
At the moment that the down-counter 82 reaches the low plateau
count, causing the comparator 88 (FIG. 3) to produce an output
pulse, a flip-flop device 100 (FIG. 5) is actuated to open a gate
102 so that clock pulses may be applied to a counter 104. By
applying the zero spooling speed signal (comparator 50, FIG. 1) to
the flip-flop device 100 at the end of the spooling cycle, the
flip-flop device 100 is again actuated to close the gate 102,
thereby to produce in the counter 104 a count c representing the
duration of slow speed spooling. The slow speed duration count c is
compared with a pair of preset reference (long and short) counts 1,
is in comparators 106,108 and, depending on which, or neither, of
the comparators 106,108 produces a coincidence pulse, one of three
flip-flop devices 110, 112,114 is actuated. (The flip-flop device
114 is actuated by a pair of inhibit devices 116,118 acting through
an AND gate 120.) A pulse generator 122, in response to a
notch-produced signal output from the photoelectric device PC-2
produces three differently phased gating pulses
.phi..sub.1,.phi..sub.2,.phi..sub.3, and, depending on whether the
slow speed duration is too long, too short, or just right, one of
such three gating pulses actuates the flip-flop device 84' to
permit down-counting pulses to be applied via the gate 86 to the
counter 82. In other words, depending on which (slow speed)
duration-indicating flip-flop device 110,112, or 114 has been
actuated, one of three AND gates 124, 128, 126, respectively, is
opened to permit, via an OR gate 130, one of the three phased
gating pulses .phi..sub.3,.phi..sub.1, .phi..sub.2, respectively,
to define the start of down-counting. FIG. 6 indicates that the
phased gating pulses have the effect of shifting the location for
the photoelectric device PC-2 so that the duration for slow speed
spooling is, in actuality, determined by the time that the system
permits for high speed spooling.
Again touching on the basic tenets of the invention -- but not on
the preferred circuit details which have been disclosed -- two
features singly and together work to provide the instant spooling
control; the control of spooling speed in accordance with the
clocking of the spooling duration; and the control of, by clocking,
a low speed spooling duration which occurs within the overall
spooling duration.
The invention has been described in detail with particular
reference to preferred embodiments thereof, but it will be
understood that variations and modifications can be effected within
the spirit and scope of the invention. For example, it would be
well within the purview of the invention to program a general
purpose computer to perform many of the teachings herein
described.
* * * * *