U.S. patent number 3,724,368 [Application Number 05/047,048] was granted by the patent office on 1973-04-03 for harmonic drive register adjustment device for a printing press.
This patent grant is currently assigned to Harris-Intertype Corporation. Invention is credited to Ernest H. Treff.
United States Patent |
3,724,368 |
Treff |
April 3, 1973 |
HARMONIC DRIVE REGISTER ADJUSTMENT DEVICE FOR A PRINTING PRESS
Abstract
A printing press includes a first printing unit having a first
blanket cylinder for printing one side of sheet material and a
first plate cylinder associated with the first blanket cylinder for
transferring an image to the first blanket cylinder. The printing
press also includes a second blanket cylinder for printing the
other side of the sheet material and a second plate cylinder
associated with it for transferring an image thereto. The first and
second blanket cylinders are positioned such that the images
received by the respective plate cylinders are applied to the sheet
material simultaneously. A register adjusting device
circumferentially adjusts the relative positions of plate cylinders
so that registry is maintained between the images applied to the
sheet material. The adjusting means includes a harmonic drive unit
drivingly connected to one of the plate cylinders so that the
rotational position of that plate cylinder with respect to the
other plate cylinder may be varied thereby.
Inventors: |
Treff; Ernest H. (Groton,
CT) |
Assignee: |
Harris-Intertype Corporation
(Cleveland, OH)
|
Family
ID: |
21946791 |
Appl.
No.: |
05/047,048 |
Filed: |
June 17, 1970 |
Current U.S.
Class: |
101/248;
101/247 |
Current CPC
Class: |
B41F
13/14 (20130101); B41F 7/12 (20130101) |
Current International
Class: |
B41F
13/08 (20060101); B41F 13/14 (20060101); B41F
7/00 (20060101); B41F 7/12 (20060101); B41f
013/12 () |
Field of
Search: |
;101/248,247,220 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
"Rigid Indexing Coupling Uses Harmonic Drive Principle," by Victor
W. Wigotsky; from April 28, 1965 Design News; Cahners Pub. .
"Use Harmonic Drives as High Ratio Differentials," from Feb. 1967,
Power Transmission Design, Industrial Publishing Co. .
"Delrin Selected for Harmonic Drive," Engineering Design 67/1, E.
I. du Pont de Nemours & Co. .
"Power Plant Employs Harmonic Drive Reducer" Dec. 1965, Pacific
Factory. .
"Compact High Reduction Single Stage," July 1966 Power Transmission
Design..
|
Primary Examiner: Pulfrey; Robert E.
Assistant Examiner: Suter; R. E.
Claims
What is claimed is:
1. A printing press comprising,
first and second cylinders defining a printing nip and having a
first position in which said cylinders are cooperable to print on
at least one side of material advanced through the nip,
said first and second cylinders comprising a blanket cylinder and
another cylinder,
a plate cylinder cooperable with the blanket cylinder for
transferring an image to the blanket cylinder,
throw-off means for bodily relatively moving said first cylinder
and said second cylinder away from said first position to a second
position and from said second position toward each other to said
first position,
means for drivingly interconnecting said first and second cylinders
when in their first and second positions, said means
comprising,
first and second gear means,
means for drivingly connecting said first gear means to said first
cylinder,
means for drivingly connecting said second gear means to said
second cylinder,
said first and second gear means having gear teeth which are
engaged to provide a drive therebetween when the cylinders are in
their first and second positions,
third gear means having gear teeth in a meshing driving relation
with gear teeth of said first gear means when said first and second
cylinders are in both said first and second positions,
means drivingly connecting said third gear means with said plate
cylinder,
the number of gear teeth on said first gear means meshing with the
gear teeth of said third gear means being less than that required
to rotate said plate cylinder at the surface speed of said blanket
cylinder,
said means drivingly connecting said third gear means with said
plate cylinder comprising a differential harmonic drive unit for
providing rotation of said plate cylinder relative to said third
gear means, said differential harmonic drive unit comprising,
an input member drivingly connected with said third gear means,
said input member having a predetermined number of internal gear
teeth thereon,
a deformable output member drivingly connected to said plate
cylinder and having a number of external gear teeth thereon less
than the predetermined number of internal gear teeth on said input
member and positioned such that said external gear teeth of said
output member are fully meshing along a portion of the periphery
thereof with said internal gear teeth,
the number of said internal gear teeth and said external gear teeth
being such as to compensate for the reduced number of gear teeth on
said first gear means so that said plate cylinder is rotated at the
surface speed of said blanket cylinder,
a wave generator member movable relative to said output member to
deform said output member such that the portion of said external
gear teeth thereon meshing with a portion of said internal gear
teeth on said input member varies to thereby vary the
circumferential position of said plate cylinder relative to said
third gear means,
a motor means drivingly connected to said wave generator member to
effect rotation of said wave generator member upon actuation
thereof,
said first gear means comprising a first pair of gears and said
second gear means comprises a second pair of gears,
said first pair of gears comprising first and second gears,
said second pair of gears comprising fourth and fifth gears,
said first and fourth gears and said second and fifth gears
respectively having an equal number of teeth which have a meshing
relationship when said first and second cylinders are in their
printing position as well as when said cylinders are in their
second position,
said first gear having gear teeth in a meshing relationship with
said third gear means, and
said first and fourth gears having a smaller pitch diameter than
said second and fifth gears, and the number of gear teeth on said
first gear meshing with said third gear means compensating for the
difference in the number of gear teeth between said internal and
external gear teeth so that said blanket and plate cylinders are
rotated at the same surface speed.
2. A printing press as defined in claim 1 wherein said second
cylinder comprises a blanket cylinder for printing on the other
side of the material advanced through the nip, and further
including,
another plate cylinder cooperable with said second cylinder
and,
sixth gear means having a meshing relationship with said fourth
gear,
means drivingly connecting said other plate cylinder and said sixth
gear means including a differential harmonic drive unit for
providing rotation of said other plate cylinder relative to said
sixth gear means.
Description
The present invention relates to a printing press, and, more
particularly, relates to a register adjusting device for
circumferentially adjusting the position of a plate cylinder
relative to a blanket cylinder in an offset printing press.
Printing presses have included mechanisms for circumferentially
adjusting one cylinder of the press relative to another cylinder.
In offset presses such adjustments have been used in conjunction
with a plate cylinder to circumferentially adjust the position of
the plate cylinder relative to a blanket cylinder. In perfecting
blanket-to-blanket presses, such an adjustment provides for
registry of the images printed on the opposite sides of the
material relative to each other. In multicolor presses, such
adjustments provide for the registry of images printed in one unit
with the images printed in another unit.
The prior art mechanisms for circumferentially adjusting a plate
cylinder relative to a blanket cylinder have been quite intricate.
One common mechanism for performing this circumferential adjustment
includes helical gears, one of which moves axially relative to the
other to thereby effect rotation of one of the gears which was
drivingly connected with the plate cylinder to thereby adjustably
rotate the plate cylinder. In perfecting presses where the plate
cylinder was intergeared with another cylinder, compensation or
provision had to be made for preventing corresponding rotation of
the cylinder which was drivingly connected with the plate cylinder.
As a result, such known mechanisms are complicated in construction
and expensive to manufacture.
The immediate invention solves these problems of the prior art
devices by providing a register adjusting device for the plate
cylinder of an offset printing press which is simplified in design.
The register adjusting device of the present invention includes a
harmonic drive unit drivingly connected to the plate cylinder of
the printing press. When the image is out of registry, the harmonic
drive is actuated so as to circumferentially rotate the plate
cylinder relative to its cooperating blanket cylinder. The design
is extremely simple and does not require other compensation devices
as are required in the afore-mentioned prior art.
Accordingly, it is an object of the present invention to provide a
new and improved circumferential register adjustment mechanism for
the plate cylinder of an offset printing press and which mechanism
is simple in construction, inexpensive to manufacture, highly
effective in operation, allows register adjustments to be made
while the printing press is in operation, and does not require the
aforementioned compensation provision.
A further object of the present invention is to provide a new and
improved register adjusting device for an offset printing press
wherein the register adjusting mechanism includes a harmonic drive
unit drivingly connected to a plate cylinder which cooperates with
a blanket cylinder and which is adapted to rotate the plate
cylinder relative to the blanket cylinder to provide
circumferential adjustment therebetween.
A still further object of the present invention is the provision of
a new and improved register adjusting device for perfecting
printing press which includes a harmonic drive unit having an input
member driven at a speed proportional to the speed of a blanket
cylinder associated with a plate cylinder, an output member adapted
to be driven by the input member and drivingly connected to the
plate cylinder, and a wave generator for creating driving
engagement between the input and output members and which is
rotated to adjust the register of the printed image with respect to
the sheet material.
Further objects, advantages, and features of the present invention
will be apparent to those skilled in the art to which it relates
from the following detailed description of a preferred embodiment
thereof, made with reference to the accompanying drawings forming a
part of this specification and in which:
FIG. 1 is a schematic view of a portion of a printing press
embodying the immediate invention;
FIG. 2 is a sectional view of the printing unit shown in FIG.
1;
FIG. 3 is another schematic view of the printing unit shown in FIG.
1;
FIG. 4 is an enlarged view of a portion of the printing unit shown
in FIG. 2;
FIG. 5 is a representative view of the portion of the printing unit
of FIG. 4, taken along the lines 5--5 thereof; and
FIG. 6 is a schematic view of a pair of printing units of the
printing press of the present invention.
The present invention provides a new and improved register
adjusting mechanism for the plate cylinder of an offset printing
press. The register adjusting mechanism of the present invention is
of a simplified construction and provides for register adjustment
while the printing press is in motion. The register adjusting
mechanism of the present invention also allows for register
adjustment to be made between printing units and between the
blanket-to-blanket cylinders of the printing units. The present
invention may be applied to printing presses of a wide variety of
constructions and designs and for purposes of illustration is
described in the drawings as applied to an offset perfecting
printing press 10, schematically shown in FIG. 1.
The printing press 10 has a printing unit 11 which includes a pair
of blanket cylinders 12, 14 defining a printing nip 15
therebetween. The blanket cylinders 12, 14 are rotatably mounted to
the press frame 101 by bearings 53, 56 (See FIG. 2), respectively,
and have plate cylinders 16, 18 associated therewith, respectively,
which transfer an image to the respective blanket cylinders 12, 14.
The blanket cylinders 12, 14 are positioned so that material 20 may
pass therebetween through the printing nip 15 and will be printed
on both sides thereof simultaneously by the blanket cylinders 12,
14. The printing press 10 may also include other printing units
similar to the printing unit 11.
One of the blanket cylinders 14 is driven by a suitable drive means
22 which is drivingly connected to the shaft 24 extending from the
blanket cylinder 14. The drive for the shaft 24 will not be
described in detail, since it does not form a part of the present
invention. Gears 26, 28 are suitably secured to the shaft 24 of the
blanket cylinder 14 and are rotated by the drive means 22. Gears
30, 32 are secured to a shaft 34 extending from the blanket
cylinder 12. The gear 26 is in a meshing relationship with the gear
30. The gears 28, 32 rotate with gears 26, 30 and drive the plate
cylinders 16, 18, respectively.
Means for circumferentially adjusting the relative positions of the
plate cylinders 16, 18, schematically indicated at 36, 38, in FIG.
1, respectively, includes harmonic drive units 40, 42. The harmonic
drive units 40, 42 include input members 44, 46, respectively. The
input members 44, 46 have gear portions 48, 50 associated therewith
respectively. The gear portions 48, 50 mesh with the gears 32, 28,
respectively. Since the gears 28, 32 are secured to the shafts 24,
34, respectively, and, consequently, rotate therewith, the gears
28, 32 rotate the input members 46, 44 of the harmonic drive units
42, 40, respectively, as a result of the meshing of the gear teeth
50, 48 with the gears 28, 32, respectively. Thus, it should be
understood that the input members 44, 46 of the harmonic drive
units 40, 42 are rotated at a speed proportional to the speed of
the blanket cylinders 12, 14.
The gears associated with the blanket cylinders 12, 14 and plate
cylinders 16, 18 have a predetermined number of teeth thereon. The
number of gear teeth on the gears 26, 30 of the blanket cylinders
14, 12, respectively, are equal so that the blanket cylinders 12,
14 are rotated at the same peripheral speed.
The plate cylinders 16, 18, as shown in the disclosed embodiment,
must be driven at the same peripheral speed as their respective
blanket cylinders 12, 14 for proper transfer of the image thereto.
Since the plate cylinders 16, 18 have a diameter equal to one-half
the diameter of the blanket cylinders 12, 14, respectively, the
gear ratio existing between the blanket cylinders 12, 14 and the
plate cylinders 16, 18, respectively, must be equal to 2 to 1 in
order for the peripheral speed of the plate cylinders to be equal
to the peripheral speed of their respective blanket cylinders. The
gears 28, 32 have a greater number of teeth than the gear portions
48, 50 of the input members 44, 46. The harmonic units 40, 42 have
a variable drive ratio so that the input members 44, 46 have a
speed greater than the speed of their output members to which the
plate cylinders 16, 18 are attached. Drive means 52, 54 are
drivingly connected to the harmonic drive units 40, 42,
respectively, so that upon actuation thereof the register of the
images applied to the blanket cylinders 12, 14 by the plate
cylinders 16, 18, respectively, may be adjusted.
It should be understood that the printing press may also include
other printing units, such as the printing unit 13, as shown in
FIG. 6. The printing unit 13 includes a pair of blanket cylinders
17, 19 which are constructed in a manner similar to that described
in connection with the blanket cylinders 12, 14, respectively, of
the printing unit 11. The blanket cylinders 17, 19 have
complementary harmonic drive units connected thereto to adjust the
register of their printing images with respect to each other and
the images of the printing unit 11.
FIG. 2 shows the gears 26, 30 mounted to the shafts 24, 34 of the
blanket cylinders 14, 12, respectively. In a like manner, the gears
32, 28 are secured to the shafts 34, 24 of the blanket cylinders.
The gears 28, 32 are secured to the shafts 24, 34 by means of keys
55. The keys 55 prohibit rotation of the gears 28, 32 with respect
to their respective shafts 24, 34. The gears 26, 30 are secured to
their respective gears 28, 32 by means of the threaded fasteners
58, so that each of the pairs of gears 30, 32 and 26, 28 rotate
about their respective axes of their respective shafts 34, 24. It
should be understood that the rotational axes of the shafts 24, 34
are positioned so that the gears 26, 30 are in meshing engagement
with each other.
The harmonic drive units 40, 42 are similar in construction and
drive their corresponding plate cylinders 16, 18 in substantially
the same manner. In addition, their input members 44, 46 are driven
by the gears 32, 28 in a similar manner. Due to this similarity of
the harmonic drive units 40, 42, the description of the harmonic
drive unit 42 which follows is equally applicable to the harmonic
drive unit 40, schematically shown in FIG. 1. The harmonic drive
unit 42 is driven by the gear 28 in a manner so that the plate
cylinder 18 is rotated thereby. It should be understood that the
harmonic drive unit 40 is driven by the gear 32 in a similar manner
so that the plate cylinder 16 is rotated in a corresponding
manner.
The gear portion 50 of the input member 46 of the harmonic drive
unit 42 is adapted to mesh with and be driven by the gear 28. The
input member 46 is rotatably supported by the bearings 60 about the
shaft 63 of the plate cylinder 18. The number of gear teeth on the
input member 46 is predetermined with respect to the number of gear
teeth on the gear 28 so that a predetermined ratio between the
speeds of the input member 46 and gear 28 is achieved.
In the disclosed embodiment, the plate cylinder 18 is shown to have
a diameter equal to one-half the diameter of the blanket cylinder
14. In order for the peripheral speed of the plate cylinder 18 to
be equal to the peripheral speed of the blanket cylinder 14, it
must be rotated at twice the rotational speed. If the input member
46 were directly connected to the plate cylinder 18, the peripheral
speeds of the plate cylinder 18 and the blanket cylinder 14 would
be equal, if the pitch diameter of the gear 28 were twice the pitch
diameter of the gear portion 50 of the input member 46 or the gear
28 had twice the number of teeth of the gear portion 50. In the
disclosed embodiment, the number of gear teeth on the gear 28 is
less than that required to rotate the plate cylinder 18 at a
peripheral speed equal to the blanket cylinder 14, and,
consequently, if the input member 46 were directly connected to the
plate cylinder 18, the plate cylinder 18 would rotate at the
slightly lower speed than the blanket cylinder 14.
The drive connection between the input member 46 and output member
64 compensates for the lower rotational speed of the input member
46. The input member 46 has a predetermined number of internal gear
teeth 62 which mesh with the external gear teeth 66 of the output
member 64. The number of external gear teeth 66 on the output
member 64 are less than the number of internal gear teeth on the
input member 46. Thus, the output member 64 rotates at a greater
rotational speed than the input member 46, as shown
hereinafter.
The number of gear teeth on the gear 28 and the gear portion 50 of
the input member are designed so that when the blanket cylinder 14
is rotated at a certain peripheral speed, the input member 46
rotates at a peripheral speed slightly lower than that of the
blanket cylinder 14, as hereinabove described. The gear 28 drives
the input member 46 through the gear portion 50, through which the
torque is transmitted to the output member 64 through the meshing
gear portions, and the plate cylinder 18 is thereby rotated. The
number of gear teeth on the gear 28, the gear portion 50 of the
input member 46, the internal gear teeth 62 of the input member and
the number of external teeth 66 on the output member are such that
the plate cylinder 18 is rotated at a peripheral speed equal to the
peripheral speed of the blanket cylinder 14.
The output member 64 is manufactured from a flexible material, such
as steel or plastic, so that it may be deformed by a wave generator
68 to position a portion of the external gear teeth 66 on the
output member 64 in meshing engagement with a portion of the
internal gear teeth 62 on the input member 46. When the wave
generator 68 is stationary, and the input member 46 is rotated, the
output member 64 will rotate at a speed greater than the rotational
speed of the input member 46, since the number of internal teeth 62
on the input member is greater than the number of external teeth 66
on the output member 64.
The relationship between the number of teeth on the drive train
connecting the blanket cylinder 14 to the plate cylinder 18 is
predetermined so that the blanket cylinder 14 drives the plate
cylinder 18 at twice the rotational speed when the wave generator
68 is stationary so that the peripheral speeds of the blanket
cylinder 14 and the plate cylinder 18 will be equal. For example,
if there are 119 teeth on the gear 28 and 60 teeth on the gear
portion 50 of the input member 46, the input member 46 will rotate
at a speed slightly less than twice the rotational speed of the
gear 28. The wave generator 68 deforms the output member 64 such
that a portion of its gears contacts the internal gear teeth 62 of
the input members 46. If there are 240 internal gear teeth,
indicated at 62, on the input member 46, and 238 external gear
teeth on the output member 64, the output member 64 will rotate at
a slightly higher speed than the input member 46. Using the number
of teeth hereinabove described, it may be calculated that the
output member 64 rotates at exactly twice the speed of the gear 28
when the wave generator 68 is stationary. Since the output member
64 is drivingly connected to the plate cylinder 18, the plate
cylinder 18 rotates at exactly twice the speed of the blanket
cylinder 14, and, consequently, the peripheral speeds of the
blanket cylinder 14 and plate cylinder 18 are equal.
The output member 64 of the harmonic drive 42 is secured to the
shaft 63 of the plate cylinder 18 and is positioned between the two
plates 70, 72. Openings 74 are provided in the plates 70, 72 and
output member 64 so that the threaded fastener 76 may pass
therethrough and be threadedly engaged by the end of the shaft 63
of the plate cylinder 18. Thus, torque is transmitted from the
output member 64 to the shaft 63 and the plate cylinder 18. The
shaft 63 rotatably supports the bearings 60 so that input member 36
is rotatably supported about the rotational axis of the shaft
63.
In order to adjust the register of the image transferred from the
plate cylinder 18 to the blanket cylinder 14, it is necessary to
rotate the plate cylinder 18 with respect to the blanket cylinder
14 in a precise and accurate manner. In order to accomplish this
objective, a drive means 54, such as the stepping motor 78, is
drivingly connected to the wave generator 68 by the shaft 80.
The shaft 80 is keyed to the wave generator 68 such that the wave
generator 68 rotates with the shaft 80. The shaft 80 is rotatably
supported in bearings 82 which are retained by the member 84
secured to the press frame. A coupling device 86 of conventional
design is provided to connect the stepping motor 78 to the shaft
80. A control unit, schematically shown at 88, is connected to the
stepping motor 78 such that the stepping motor 78 may be rotated in
either direction which may be determined by the printing press
operator. By actuating the control device 88, the stepping motor 78
is rotated a predetermined amount in a predetermined direction and,
consequently, the wave generator 68 is rotated. When the wave
generator 68 is rotated, the position of the portion of the
external gears 66 on the output member 64 engaging the internal
gears 62 on the input member 46 moves with respect to the input
member 46 and, thus, the phase relationship between the plate
cylinder 18 and blanket cylinder 14 is changed. Consequently, the
position of the image transferred to the blanket cylinder 14 by the
plate cylinder 18 is varied with respect to the remainder of the
images printed by the press. A detailed description of the harmonic
drive unit can be obtained by reference to U.S. Pat. No. 2,906,143,
which further explains the operation of the wave generator and the
phase change brought about thereby.
It should be understood that the stepping motor 78 may be rotated
in either direction so that the registry of the images transferred
to the blanket cylinder 14 may be adjusted in either direction. The
stepping motor 78 is designed such that it prohibits the shaft 80
from rotating when the stepping motor 78 is not rotated. Thus, the
gear ratio of two-to-one between the blanket cylinder 14 and plate
cylinder 18 is thereby maintained when the stepping motor 78 is not
actuated.
The printing press 10 also includes a throwoff mechanism, as seen
in FIG. 3 and generally indicated 100, which moves the blanket
cylinders 12, 14 away from each other and their respective plate
cylinders 16, 18. It should be understood that the throwoff
mechanism 100 may be of any conventional design and the design
shown in FIG. 3 is merely representative of one design. The
throwoff mechanism 100 includes an actuator, such as an air
cylinder 102 for creating such movement. One end of the cylinder
102 is pivotally mounted to a mounting bracket 104 which is in turn
secured to the frame 101 of the printing press. The rod 106 of the
cylinder 102 is pivotally secured to the arm 111 of a crank member
108 about the axis 110 of the arm 111. The crank member 108 is
pivotally mounted about a pin 112 secured to the frame 101 of the
printing press 10 and rotates thereabout. The other arm 114 of the
crank member 108 is pivotally mounted to a link 116 about the axis
118.
The link 116 is also pivotally connected, as shown in FIG. 3, to an
eccentric 120 which supports the bearings 56 associated with the
blanket cylinder 14. When the crank member 108 is rotated by the
piston 102 from a first position, generally indicated at 124, to a
second position 126, the eccentric 120 moves the blanket cylinder
14 from a printing position 128 to a disengaged, nonprinting
position 130. In the printing position 128, the blanket cylinder 14
is in a printing relationship with respect to the plate cylinder 18
of the blanket cylinder 12. When the blanket cylinder 14 is in the
disengaged position 130, the blanket cylinder 14 is out of
engagement with the plate cylinder 18 and blanket cylinder 12 so
that the sheet material may pass through the printing nip defined
by the blanket cylinders 12, 14 without marking or printing of the
sheet material.
The throwoff mechanism 100 also includes a connecting link 132
secured to the eccentric member 120 of the blanket cylinder 14
which is connected to an eccentric member 134 which supports the
bearings 53 associated with the blanket cylinder 12. When the
blanket cylinder 14 is in a disengaged position 130, the blanket
cylinder 12 is also moved in a disengaged position 136, since the
link 132 moves the eccentric 134 when the eccentric 120 is moved.
Correspondingly, when the blanket cylinder 14 is in a printing
position 128, the blanket cylinder 12 is in a printing position
138. When the blanket cylinders 12, 14 are in a nonprinting
position 130, 136, the gears 26 and 30 remain in meshing engagement
with each other. This enables the cylinders to be rotated thereby
for make-up and other purposes when the blanket cylinders are in
nonprinting position. The intermeshing gears 28, 32 still have
their teeth in mesh when the blanket cylinders are in non-printing
position. However, the overlap of the gear teeth is slight, since
their pitch diameters are less than the pitch diameters of gears
26, 30, hence they are only in partial engagement even before the
cylinders are thrown off impression. Due to this slight overlap,
these gears, when the blanket cylinders are thrown off, may not
reliably carry the drive forces for driving the cylinders. This
makes gears 26, 30 important for driving the cylinders when the
blanket cylinders are in nonprinting position.
* * * * *