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Патент USA US3049286

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Aug- 14, 1962
R. E. WILKINS
3,049,276
PAPER FEED MECHANISM
Filed Oct. 21, 1960
INVENTOI?
ROBERT E. W/LK/NS
B)’
y;
ATTORNEY
Uite States Patent O??ce
3,@49,Z76
Patented Aug. 14, 1952
1
2
3,049,276
wherein the relative phase of a pair of paper advancing
means may be varied by manipulating the belt linkage
PAPER FEED lvIEtZHANlSlvl
Robert E. Wilkins, Wollaston, Mass, assignor to Minne
apolis-Honeywell Regulator Company, Minneapolis,
Mind, a corporation of Delaware
Filed Got. 21, 196i}, Ser. No. 64,030
12 Claims. (Cl. 226-74)
This invention relates in general to a new and improved
web feed mechanism, in particular to a paper feed mecha
nism for a high-speed printer in which the paper is ad
vanced past a print station under tension.
of one of them without producing excessive belt tension.
It is an additional object of this invention to provide
a webbed feed mechanism for a high-speed printer which
is simple and economical in construction and which per
mits accurate control of the tension of the web.
The foregoing objects are carried out in the present in
vention by manipulating the belt linkage of one of a
pair of synchronously operating tractors which cooperate
to advance the paper web past an inter-mediately posi
tioned print station. The belt linkage comprises a pair
of opposite facing belt sections which move in opposite
Present-day high-speed printers which are capable of
printing speeds of the order of 1,000 lines per minute
directions and which engage the drive gear of the ma
require a paper feed mechanism which is capable of 15 nipulated tractor. Each belt section threads separate
advancing the paper web rapidly past the print station
guide means stationed between the driving source and the
while maintaining accurately controllable tension in the
drive gear. The guide means may be jointly moved so
web. Proper paper tension is important in order to obtain
that the path of one belt section is effectively lengthened
a printed product of high quality.
at the expense of the path of the other belt section, while
In the case where the paper web is advanced by means
the points of tangency of both belt sections are simul
of perforations along its edges which are engaged by the
taneously shifted around the periphery of the tractor
pins of a pair of synchronously moving tractors stationed
drive gear. The symmetrical manner in which the guide
means operate on the belt linkage prevents excessive belt
on opposite sides of the print station, the paper tension
may be conveniently adjusted while the paper feed opera
tension from occurring with the associated adverse ef
tion is in progress by varying the relative phase of the 25 fects discussed above.
tractors. Where one of the tractors is belt-coupled to its
drive source with the belt linkage forming a pair of op
posite belt sections which engage the tractor drive gear,
the coupled drive tractor may be advanced or retarded
relative to the other tractor by lengthening one of the
aforesaid opposite belt sections at the expense of the other
The various novel features which characterize the in
vention are pointed out with particularity in the claims
annexed to and forming a part of this speci?cation. For
a better understanding of the invention, its advantages
and specific objects thereof, reference should be had to
the following detailed descriptions and the accompanying
drawing, the single FIGURE of which illustrates a pre
ferred embodiment of the invention.
With reference now to the drawing, suitable perfora
sections engage the periphery of the drive gear. If one 35 tions along the edges of a continuous paper web 10‘ are
considers that the belt sections are roughly symmetrical
engaged by the pins of a pair of tractors 12 and 14 re
with respect to a center line through the tractor drive
spectively, ‘which are spaced on opposite sides of a print
gear axis, any angular rotation of the center line about
station 15. A pair of ?xed paper guides 18 and 20 is
the axis will shift the points of tangency of the belt sec
disposed between the tractors 12 and 14 respectively and
40
tions about the periphery of the drive gear. Since one
the print station to provide the proper position at the
one.
Another technique for accomplishing the same result is
to shift the points at which the aforesaid opposite belt
of the belt sections now engages the drive gear earlier
print station.
The tractor 12 is seen to consist of a
than before while the other belt section engages the drive
tractor drive gear 22 having a coaxial portion 24 of re
gear later, the phase of the tractor With respect to the
duced diameter. An idler gear 26 is spaced from the
other tractor is shifted.
drive gear 22 and cooperates with the portion 24 of the
Past attempts at implementing a satisfactory tractor 4:5 latter to drive an endless tractor chain 28. In similar
phasing arrangement in a paper feed mechanism of the
manner, the tractor 14 comprises a tractor drive gear 32
type described have been largely unsuccessful. The ma
whose reduced diameter portion 34 cooperates with a
nipulation of the opposite belt sections which couple the
spaced idler gear 36 to drive another endless tractor chain
tractor drive gear to the driving source in prior art de
38. The tractor chains 28 and 38 carry the aforesaid
vices inevitably produces excessive belt tension in at least 50 pins which engage the perforations of the continuous
one of these belt sections. In some prior art devices, the
total length of the belt linkage path actually varies dur
ing the aforesaid manipulation and produces excessive
belt tension and slack. More commonly, however, the
tension in a single belt section becomes temporarily ex
cessive in presently available equipment, but is equalized
in one complete traversal of the belt path. The unequal
belt tension which exists during this interval may pro
duce permanent stretching of the belt. Moreover, the
added belt tension, however temporary, places an addi 6 O
paper web 10.
The drive source for both tractors is seen to be a
drive wheel 4% which is adapted to rotate about a pivot
54 and is powered from a motor 42. The tractor drive
gear 22 is coupled to the drive wheel 49 by means of a
belt linkage 42. A belt linkage 44 which includes a pair
of opposite belt sections 46- and 48 respectively couples
tional strain on the bearings of the driving source and of
the tractor drive gear and is instrumental in producing
the tractor drive gear 32 to the drive wheel 40. The
opposite belt sections 46 and 48 engage the drive gear
32 at the points of tangency 51 and 53 respectively. These
tangency points, as well as the opposite belt sections
themselves, are roughly symmetrical with respect to a
vibrations.
Accordingly, it is the primary object of this invention
center line 49 passing through the pivot 52. A support
ing plate 5% is rotatably positioned about a pivot 56
to provide a few feed mechanism for a high-speed printer
between the tractor drive gear 32 and the drive wheel 40,
which overcomes the foregoing disadvantages.
the pivots 52 and 54 respectively of the latter being aligned
with the pivot 56. Two pairs of rotatable pulleys 53,
It is another object of this invention to provide an i1n—
proved web feed mechanism for a 'higl-speed printer
60 and 62, 64 are symmetrically positioned on the sup
wherein the tension of the web is accurately controllable. 70 porting plate ‘50 with respect to the pivot 56 of the latter.
It is a ,further object of this invention to provide a
The supporting plate 5% further includes a geared pe
paper web feed mechanism for a high-speed printer
ripheral section 66 which engages a worm gear 68. The
3,049,276
4
3
worm gear is rotatably supported in a bracket 79 and
includes an extension 72 which terminates in an adjust~
tions 46 and 48 remaining symmetrically disposed with re
ing knob 74.
spect thereto. The incoming belt section 46 will be seen to
engage the periphery of the tractor drive gear 32 at a
The belt section 46 is seen to thread the pulleys 53
and 60 which are in contact with the opposite sides of
leaves the tractor drive gear 32 at a later point in time.
the belt section. The pulleys produce substantially op
posite de?ections of the path of the belt section 46 which
is seen to be divided into a pair of laterally displaced
later point in time, and the outgoing belt section 48
The results of effectively lengthening the belt section
46 at the expense of the belt ‘section 48, and of the shift
of the tangency points 51 and 53 in a counterclockwise
direction along the periphery of the track drive gear 32,
path portions 46a and 46b. The magnitude of the dis
placement is determined by the length of a third por 10 combine to advance the position of the drive gear 32 in
tion 460 of the belt section 46. In similar manner, the
belt section 48 threads the pulleys 62 and 64 in a manner
a counterclockwise direction with respect to the drive gear
22 whose position is unaffected. Accordingly, the phase
of the tractor 14 is advanced with respect to that of the
where the de?ections produced by the pulleys divide it
tractor 12 in order to Obtain increased tension in the
into a pair of laterally displaced path portions 43a and
48b. The magnitude of the path displacement is deter 15 continuous paper web 10.
Owing to the symmetry of the pulleys with respect to
mined by the length of a third path portion 430. It will
the pivot 56 of the supporting plate 56, the e?ect on the
be noted that the lateral displacements of the belt sec
belt sections 46 and 43 of rotating the supporting plate
tions 46 and 48 intermediate their paths are of opposite
are precisely balanced. Thus, in the case of the clock
direction.
wise rotation of the supporting plate which was explained
In operation, the tractors 12 and 14, being directly
above, the decrease in the lateral displacement of the pat
coupled to the same driving source, rotate in synchronism
portions 46a and 46b is precisely offset by the increase in
to advance the paper web 10‘v past the print station 16
the lateral displacement of the path sections 48a and 48b.
in the direction of the arrow 80. The corresponding direc
by means of appropriate arrows.
Similarly, the shift of the tangency point 51 in a counter
clockwise direction along the periphery of the tractor
gear 32 is offset by a corresponding shift in the counter
clockwise direction of the tangency point 53. It will be
I If it is desired to increase the paper tension, the trac
tor drive gear 32 must be advanced with respect to the
tractor drive gear 22, i.e. it must be rotated in a counter
appreciated that the reverse situation is true if the com
mon supporting plate 50 is rotated in the counterclock
wise direction in order to decrease the tension of the
clockwise direction. In order to accomplish this object,
the belt sections 46 and 48 are manipulated by rotating
paper web 10 by retarding the phase of the tractor 14
with respect to that of the tractor 12. In either case,
excessive tension is avoided in the belt sections 46 and 48
respectively so that belt stretching, vibrations and undue
tion of rotation of the drive wheel 40, the tractor drive
gears 22 and 32, as well as the direction of motion of
the respective belt linkages, is indicated in the drawing
the common supporting plate 50 in a clockwise direc
tion. This rotation is carried out by turning the knob
74, whose turning motion is applied to the worm gear
'68 to rotate the supporting plate about its pivot 56.
As the rotation of the supporting plate proceeds, the
position of the pulleys 58 and 60‘ with respect to each
other changes in a manner to decrease the lateral dis
strains on the pivots 52 and 54 from this source are
eliminated.
'
The invention is not con?ned to the illustrated pre
ferred embodiment and is subject to diiferent modi?ca
tions as the needs of the particular printer in which the
placement of the portions 46a and 46b, determined by the
length of the portion 460. Since the path of the belt
mechanism is employed may dictate. For example, the
section 46 has been shortened without decreasing the
common source, provided only that they rotate in syn
length of the belt section itself, an excess amount of belt
chronism with each other.
sections results. In effect, the belt section 46 is thereby
source is used, the drive gear 22 may be directly geared
is, of course, obtained from the excess of the belt section
belt section 46 may engage the pulley 60 on its under
surface in the drawing and contact the pulley 58 on its
tractor drive gears 32 and 22 need not be driven from a
Where a common drive
lengthened. Simultaneously, the lateral displacement of 45 to the drive source if desired. It will be further under
stood that the relative phase of the two tractors de
the path portions 48a and 48b is increased (as measured
termines the tension in the paper web. Accordingly, it
by the length of the path portion 48c) by an amount
may be desirable to operate on both tractors in order to
equal to the corresponding decrease in the belt section
vary their relative phase.
46. This results in a corresponding increase in the path
The belt sections 46 and 48 need not thread their re
length of the belt section 48, in effect shortening the
spective pulley pairs in the manner shown. Thus, the
latter. The additionally required length of belt section
46 since the two actions proceed simultaneously and they
are equal in the degree of change brought about.
In the drawing, the belt sections 46 and 48 are shown
as being symmetrically disposed with respect to the center
line 49 which passes through the pivot 52 of the tractor
drive gear 32. As previously explained, this position de
termines the points of tangency 51 and 53 where the
belt sections 46 and 48 respectively engage the drive gear
32. When the common supporting plate 50 is rotated in a
clockwise direction, the pulleys 58 and 60 are moved out
of the path of the belt section 46 by an amount depending
upon the magnitude of the angular rotation of the sup
porting plate.
upper surface. A corresponding change is required with
respect to the pulleys 62 and 64. In the latter case, given
the indicated direction of web travel, the clockwise rota
tion of the supporting plate 50 will produce slack in the
paper web while a counterclockwise rotation'will produce
greater tension.
It will also be understood that ?xed guides, attached to
the common supporting plate, could be substituted for the
rotatable pulleys. It is also possible to have the guide
pairs movably disposed separately of each other, provided
only that a simultaneous manipulation of the belt sections
65 may be effected in equal amounts.
The result of this movement is to shift the tangency
It will be apparent from the foregoing disclosure of the
point 51 in a counterclockwise direction along the periph
invention that numerous modi?cations, changes and
ery of the drive gear 32. Simultaneously, the pulleys 62
equivalents will now occur to those skilled in the art, all
and 64 are increasingly rotated into the path of the belt 70 of which fall Within the true spirit and scope contem
section 48 so that the tangency point 53 is shifted by a cor
plated by the invention. What is claimed is:
responding amount in the same direction along the periph
1. ‘In a web feed mechanism for a high-speed printer
ery of the tractor drive gear 32. The effect may be visual
including ?rst and second spaced web advancing means
ized by rotating the center line 49 in a counterclockwise di
and means for driving said web’ advancing means in syn
rection about the tractor drive gear pivot 52, the belt sec 75 chronism‘with each other, at least one of said driving
w
3,049,276
6
means including a belt linkage having a pair of opposite
belt sections, means for adjusting the tension of said web
of contact points on said one web advancing means, a
web tension adjustment comprising a common support
rotatably disposed about a pivot, a pair of guide means
symmetrically positioned on said support with respect to
comprising, means disposed on a common support to
eifect substantially opposite, intermediate de?ections of
said pivot, each of said guide means engaging opposite
the path of each of said belt sections, and means for
selectively positioning said common support to produce
opposite changes of the lengths of said paths to vary the
relative phase of said web advancing means.
sides of one of said belt sections which link said one web
advancing means, said pair of guide means being posi
tioned to produce substantially opposite displacements
of the paths of said belt sections, and means for rotating
2. In a web feed mechanism for a high-speed printer
having ?rst and second web advancing means adapted to 10 said common support to shift said contact points of said
opposite belt sections on said one web advancing means
invariantly engage said web and to operate in synchronism
in a chosen direction while increasing the effective length
with each other, at least one of said web advancing means
of a selected one of said opposite belt sections at the
being coupled to a power source by a belt linkage includ
expense of the other one.
ing a pair of opposite belt sections, each of said belt
7. In a paper feed mechanism ‘for a high-speed printer
sections having a pair of opposite sides, a web tension 15
having ?rst and second spaced paper advancing means
adjustment comprising guide means engaging said oppo
adapted to operate in synchronism with each other, at
site sides of each of said belt sections which link said one
least one of said paper advancing means being coupled
web advancing means, said guide means effecting a sub
to a power source by a belt linkage including a pair of
stantially lateral displacement of the path of each of said
belt sections by producing substantially opposite de?ec 20 opposite belt sections, a paper tension adjustment com
prising a supporting plate rotatably disposed about a
pivot, two pairs of rotatable belt guides symmetrically
positioned on said supporting plate with respect to said
pivot, the guides of each of said pairs being positioned
tions of the latter, and means for simultaneously eifecting
opposite changes of said displacements to vary the phase
of said one Web advancing means with respect to the
other one.
3. In a web feed mechanism having ?rst and second 25 to engage opposite sides of respective ones of said belt
sections which link said one paper advancing means to
Web advancing means adapted to invariantly engage said
effect a substantially lateral displacement of the belt sec
web and to operate in synchronism with each other, at
tion path, said guide pairs displacing the paths of said
least one of said web advancing means being coupled to
belt sections in substantially opposite directions, said sup
a power source by a belt linkage including a pair of
opposite belt sections which extend to a pair of contact 30 porting plate further including a geared portion, and
means engaging said geared portion for selectively rotat
points on said one web advancing means, each of said
ing said supporting plate about its pivot, said rotation be
belt sections having a pair of opposite sides, a web tension
ing adapted to effect opposite changes of said path dis
adjustment comprising guide means engaging said oppo
placements to vary the relative phase of said paper ad
web advancing means, and means for varying the position 35 vancing means.
8. A mechanism for feeding paper past the print station
of said guide means to shift said contact points of said
site sides of each of said belt sections which iink said one
of a high-speed printer, comprising ?rst and second trac- ,
opposite belt sections on said one web advancing means
tors stationed on opposite sides of said print station each
invariantly adapted to engage said paper, means for driv
of a selected one of said opposite belt sections at the ex
40
ing said tractors in synchronism, the driving means asso
pense of the other one.
ciated with at least one of said tractors including a belt
4. In a web feed mechanism for a high-speed printer
linkage having a pair of opposite belt sections, each of
having ?rst and second web advancing means adapted to
said belt sections having a pair of opposite sides, a paper
operate in synchronism with each other, at least one of
tension adjustment including guide means engaging said
said web advancing means being coupled to a power
source by a belt linkage including a pair of opposite belt as CA opposite sides of each of said belt sections which link
said one tractor, said guide means being positioned to
sections, a web tension adjustment comprising a pair of
provide an increment of the path length of each of said
guide means disposed on a common support and engag
belt sections by means of substantially opposite de?ections
ing opposite sides of each of said belt sections which link
of the latter, and means for simultaneously effecting op
said one web advancing means, said guide means being
in a chosen direction while increasing the effective length
positioned to produce substantially opposite displace
ments of the paths of said belt sections, and means for
moving said common support to effect simultaneous,
opposite changes of said displacements to vary the rela
tive phase of said web advancing means.
5. In a web feed mechanism having ?rst and second
web advancing means adapted to operate in synchronisrn
with each other, at least one of said web advancing means
being coupled to a power source by a belt linkage includ
ing a pair of opposite belt sections, a web tension adjust
ment comprising a common support rotatably disposed
about a pivot, a pair of guide means symmetrically posi
tioned on said support with respect to said pivot, each of
said guide means engaging opposite sides of one of said
belt sections which link said one web advancing means,
50
posite changes of said increments to vary the phase of
said one tractor with respect to the other one.
9. A mechanism for feeding paper past the print station
of a high—speed printer, comprising ?rst and second trac
tors stationed on opposite sides of said print station each
invariantly adapted to engage said paper, means for driv
ing said tractors in synchronism, the driving means asso
ciated with at least one of said tractors including a trac
tor drive gear coupled by a belt linkage having a pair of
opposite belt sections which extend to ?rst and second
points of tangency on said drive gear, each of said belt
sections having a pair of opposite sides, a paper tension
adjustment including guide means engaging said opposite
sides of each of said belt sections which link said one
tractor, said guide means being positioned to provide an
increment of the path length of each of said belt sections
said pair of guide means being positioned to produce sub
by
means of substantially opposite de?ections of the latter,
stantially opposite displacements of the paths of said belt
and means for varying the position of said guide means
sections, and means for rotating said common support to
to shift said points of tangency of said opposite belt sec
effect opposite changes of said displacements to vary the
tions in a chosen direction about the periphery of said
relative phase of said web advancing means.
70 drive gear while increasing the effective length of a se
6. In a web feed mechanism having ?rst and second
web advancing means adapted to Operate in synchronism
with each other, at least one of said web advancing means
being coupled to a power source by a belt linkage includ
lected one of said opposite belt sections at the expense of
the other one.
10. A paper feed mechanism for a high-speed printer
comprising ?rst and second tractors stationed on opposite
ing a pair of opposite belt sections which extend to a pair 75 sides of a print station, each adapted to engage said
3,049,276
7
paper,,means‘ for driving said tractors in'synchronism,
the driving means associated with at least one of said
tractors including a tractor drive gear coupled by a belt
8
ing plate about its pivot point, said rotation producing
opposite changes of said path displacements to vary the
phase of said one tractor with respect to the other one.
linkage having a pair of opposite belt sections which ex
12. A high-speed printer feed mechanism for advanc
tend to ?rst and second points of tangency on said
drive gear, a paper tension adjustment including a sup
ing a perforated paper web past a print station, com
prising ?rst and second tractors positioned at the en
porting plate rotatably disposed about a pivot, two pairs
of rotatable belt guides symmetrically positioned on said
supporting plate with respect to said pivot, the rotatable
trance and exit sides respectively of said print station,
each of said tractors including rotatable drive and idler
guides of each of said pairs being positioned to engage
opposite sides of respective ones of said belt sections
said tractor chain being adapted to engage the perfora
tions of said paper web, a drive wheel coupled to a drive
motor, an endless belt comprising a pair of opposite belt
sections coupling each of said tractor drive ‘gears to
which link said one tractor to effect a substantially lateral
displacement of the belt section path, said guide pairs
displacing said paths in substantially opposite directions,
said supporting plate further including a geared portion,
means engaging said geared portion for selectively rotat
ing said supporting plate about its pivot point, said rota
tion producing opposite changes of the magnitudes of
said path displacements; whereby said points of tangency
of said opposite belt sections are shifted in a chosen di
rection about the periphery of said drive gear while the
length of a selected one of said pair of opposite belt sec
tions is increased at the expense of the other one.
11. A paper vfeed mechanism for a ‘high-speed printer
comprising ?rst and second tractors stationed on oppo
site sides of a print station, each adapted to engage said
paper, means for driving said tractors in synchronism,
the driving means associated with at least one of said
tractors including a belt linkage having a pair of oppo
site belt sections, a paper tension adjustment including a
supporting plate rotatably disposed about a pivot, said
pivot being symmetrically positioned between said oppo
site belt sections, two pairs of rotatable belt guides sym
metrically positioned on said supporting plate with respect
to said pivot, the rotatable guides of each of said pairs
being positioned to engage the opposite sides of respec
tive ones of said belt sections which link said one tractor
to effect a substantially lateral displacement of the belt
section path, said guide pairs displacing said paths in
substantially opposite directions, said supporting plate
further including a geared portion, a worm gear engaging
said geared portion for selectively rotating said support
gears and an endless tractor chain driven by said gears,
said drive wheel, said belts being adapted to drive said
tractors in the same direction, a supporting plate posi
tioned intermediate said drive wheel and the drive gear
of said second tractor, said supporting plate being rotat
ably disposed about a pivot symmetrically positioned
between said opposite belt sections, a worm gear, a cir
cumferential section of said supporting plate being
adapted to engage said worm gear, means for selectively
turning said worm gear to rotate said supporting plate
about its pivot, two pairs of rotatable pulleys symmet
rically positioned on said supporting plate on opposite
sides of said pivot, each of said pulley pairs being
threaded by one of said opposite belt sections which
link said second tractor drive wheel, said pulley pairs
dividing each of said threading belt sections into separate
portions laterally displaced from each other in mutually
30 opposite directions, the rotation of said supporting plate
about its pivot point effectively increasing the magnitude
of one of said lateral displacements at the expense of the
other displacement to change the phase of said second
tractor drive wheel relative to that of said ?rst tractor
drive wheel.
References Cited in the ?le of this patent
UNITED STATES PATENTS
2,347,900
2,348,862
Frazer-Nash et a1. _____ __ May 2, 1944
Sorkin ______________ __ May '16, 1944
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