Axially adjustable register pin

An axially adjustable register pin for a plate cylinder of a rotary printing machine is positioned in a recess in an insertion bar that is carried in a cylinder gap on the periphery of the plate cylinder. The register pin is axially slidable and is held in a selected position by holding devices that are attached to the insertion bar. Each holding device has a cantilever arm and the register pin has lower arms that engage the undersurfaces of the cantilever arms. Set screws are used to hold the lower arms against the cantilever arms.

FIELD OF THE INVENTION 
The present invention is directed generally to an axially adjustable 
register pin. More particularly, the present invention is directed to an 
axially adjustable register pin for a plate cylinder of a rotary printing 
press. Most specifically, the present invention is directed to an axially 
adjustable register pin assembly including a clamping or holding assembly 
for fixing the portion of the axially adjustable register pin. The 
register pin has an upper register position which is engageable with 
register slots in the leading and trailing edges of a printing plate 
secured to the plate cylinder; and a fastening portion that is receivable 
in an axially extending slot in an insertion bar that is received in a 
cylinder gap in the periphery of the plate cylinder. The fastening portion 
carries set screws that are operable to axially fix the register pin at a 
desired location in the cylinder gap of the plate cylinder. 
DESCRIPTION OF THE PRIOR ART 
Many printing operations are accomplished by passing an elongated paper web 
through a series of rotary printing units which together form a rotary 
press assembly. This is frequently the situation when the paper web being 
printed is to have multiple colors or types of printing steps performed on 
it. In such rotary presses that have several axially arranged printing 
units, it is often the case that the printed paper web changes its width 
from printing unit to printng unit. Such changes in width are often caused 
by absorption of dampening fluid during the printing operation and by 
other changes in the state of the paper. These width variations in the 
paper web, can cause printing errors and register errors. 
Various attempts have been made to provide axially shiftable register pins 
so that the position of the printing plate on the surface of the plate 
cylinder can be shifted axially to compensate for paper web width changes. 
In one prior device that is set forth in German published unexamined 
patent application No. 3,545,297 the register pins for two printing plates 
that are arranged adjacent each other on a plate cylinder can be axially 
shifted by means of a side register adjusting device. Each of the register 
pins is linked to each other by means of an adjusting bar or an adjusting 
tubular shaft by means of threads having different pitches. This adjusting 
bar or shaft is rotatable by an adjusting screw. 
In a device of the type set forth in this prior arrangement the register 
pins for the two printing plates which are positioned adjacent each other 
always have to be adjusted simultaneously and both at the same rate. It is 
not possible to attain better printing quality by effecting the adjustment 
of only one of the register pins with a device of this type. A connecting 
bar between the register pin and the adjusting screw has a substantial 
length which is required to reach the adjustable register pins that are 
located near the middle of the cylinder. This long connecting bar requires 
suitable guide bushings and supports so that register accuracy does not 
diminish with increasing distance from the adjusting screw. The resultant 
adjusting assembly is quite complicated in construction and requires a 
significant amount of space. It thus is costly to manufacture and 
increases the size and complexity of the plate cylinder. 
An alternative assembly that is intended for use in plate registry is shown 
in German published unexamined patent application No. 2,045,953. This 
device provides a stop in the plate cylinder gap. This stop is positioned 
at one end of the gap and is in the form of a clamping bushing which 
engages one side or end of the printing plate. Since this device contacts 
only one side edge of the printing plate, the plate is secured against 
lateral movement in only one direction. With this type of assembly, it is 
not possible to facilitate a lateral positioning of both sides of the 
printing plate at the same time. In this prior device, it is also not 
possible to use the stop as a register pin. The stop, since it is in the 
form of a clamping bushing changes its external shape during clamping. 
Thus a measurement, taken before clamping of the bushing, will be changed 
by the clamping itself. 
It will thus be seen that a need exists for an axially adjustable register 
pin assembly that overcomes the limitations of the prior devices. The 
axially adjustable register pin assembly in accordance with the present 
invention provides such a device and is a substantial improvement over the 
prior devices. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide an axially adjustable 
register pin. 
Another object of the present invention is to provide an axially adjustable 
register pin for a plate cylinder of a rotary press. 
A further object of the present invention is to provide an axially 
adjustable register pin for a plate cylinder in which the register pin can 
be fixed in place separately. 
Yet another object of the present invention is to provide an axially 
adjustable register pin that is positionably secured in a cylinder gap of 
a plate cylinder. 
Still a further object of the present invention is to provide an axially 
adjustable register pin that is securable by a pair of spaced holding 
devices. 
Even yet another object of the present invention is to provide an axially 
adjustable register pin that is adjustable along an insertion bar carried 
in the cylinder gap of a plate cylinder. 
As will be discussed in greater detail in the description of the preferred 
embodiment which is presented subsequently, the axially adjustable 
register pin in accordance with the present invention includes a register 
portion and a fastening portion. The register portion has opposing 
register ends that are received in register slots in the leading and 
trailing ends of a printing plate that is clamped to the surface of the 
plate cylinder. The fastening portion of the register pin includes two 
outwardly directed fastening ends. Each end is held beneath a cantilever 
or projection on a holding device. The holding devices are, in turn, 
secured in a gap in an insertion bar positioned in the cylinder gap of the 
plate cylinder. Each fastening end of the register pin carries a set screw 
that is accessible through an elongated slot in the overlying cantilever 
arm of the holding device. The set screws can be loosened to allow the 
register pin to be slid axially in the gap in the insertion bar. Once the 
register pin has been properly located, the set screws are tightened to 
hold the register pin in place. 
A significant advantage of the axially adjustable register pin of the 
present invention is that each printing plate can be laterally 
repositioned individually without shifting or displacing the entire 
printing plate device. The axially adjustable register pin of the present 
invention does not utilize lengthy screws or adjusting bars and is not 
expensive to manufacture or maintain. It can be used with plate cylinders 
having bearer rings as well as plate cylinders without bearer rings. 
The axially adjustable register pin in accordance with the present 
invention overcomes the limitations of the prior devices and is a 
significant advance in the art.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring initially to FIG. 1, there may be seen a preferred embodiment of 
an axially adjustable register pin assembly in accordance with the present 
invention. A plate cylinder 2 of a rotary printing press is provided with 
a generally conventional, axially extending cylinder gap 1 at its 
periphery. An insertion bar 3 is securely positioned in the cylinder gap 1 
and carries a pair of generally parallel, axially extending and 
circumferentially spaced printing plate end clamping and fixing devices 4 
and 6. These plate end clamping devices 4 and 6 are rotatable in either 
direction in a generally known manner to clamp and fix the leading and 
trailing ends of a printing plate 7 which is to be secured to the outer 
peripheral surface of the plate cylinder 2. The insertion bar 3 can be 
removed from the cylinder gap 1 and is held in place by suitable means 
that are not specifically shown. 
One or more printing plates 7 may be attached to the insertion bar 3 and 
held in place on the plate cylinder 2. One or more recesses or openings 9 
are provided in the insertion bar 3 with the shape of each such recess 
being best seen in FIG. 3. Each recess is structured to receive an axially 
adjustable register pin, generally at 11, in accordance with the present 
invention. A pair of spaced register pin holding devices, generally at 12 
and 13 as seen most clearly in FIGS. 2 and 3 are provided to axially 
adjustably position each register pin 11. It will be understood that the 
insertion bar 3 could have a suitable aperture instead of a recess 9 and 
that the register pin could be secured directly to the plate cylinder body 
2. 
As may be seen by referring to FIGS. 1 and 2, the register pin 11 has an 
upper register portion 26 and a lower fastening portion 24. The lower 
fastening portion 24 cooperates with the register pin holding devices 12 
and 13, as may be seen most clearly in FIGS. 2 and 3. The right holding 
device 13 is generally a rectangular block that has a first cantilever arm 
or projection 17 which extends toward the register pin 11 and which 
overlies a right end 28 of the fastening portion 24 of the register pin 
11. A tapered pin 14 extends through the rectangular body of the right 
holding device 13 and is received in a suitable opening in the insertion 
bar 3. The cantilever projection 17 cooperates with a bottom surface 18 of 
the insertion bar 3 to form a guide slot 19 for the right lower arm 28 of 
the fastening portion 24 of the register pin 11. The right holding device 
13 is secured to the insertion bar 3 by use of a threaded fastening screw 
16 that passes through the rectangular body generally adjacent the taper 
pin 14. 
The left holding device 12 is structured essentially the same as the right 
holding device 13. It has a generally rectangular body which carries a 
threaded fastening screw 21 that is used to secure the left holding device 
12 to the insertion bar 3. A left cantilever arm or projection 22 overlies 
a left lower arm 27 of the fastening portion 24 of the register pin 11. 
This left cantilever arm 22 is spaced from, and cooperates with the bottom 
surface 18 of the insertion bar 3 to form a left guide slot 23 in which 
the left lower arm 27 of the register pin 11 is slidable. 
The two holding devices 12 and 13 are positioned in the recess 9 of the 
insertion bar 3 so that there is maintained a space "a" between the free 
ends of the cantilever arms 17 and 22 of generally about 6 mm. It is 
within this space "a" that the register pin 11 is axially slidable. As may 
be seen most clearly in FIG. 3, the circumferential width of the recess 9 
in the insertion bar 3 is generally the same as the width of the 
rectangular bodies of the two holding devices 12 and 13. This prevents the 
holding devices from moving circumferentially in the recess 9. 
As may be seen most clearly in FIG. 2, and has been alluded to above, the 
register pin 11 is generally shaped as an inverted T in a cross-section 
taken in the axial direction of the plate cylinder 2. The fastening 
portion 24 is formed by the lower left and right arm 27 and 28 while the 
register portion 26 extends upwardly toward the surface of the plate 
cylinder 2. As was discussed previously, the lower left and right arms 27 
and 28 are positioned in left and right guide slots 23 and 19, 
respectively and allow the register portion 26 to slide axially in the gap 
or space "a" between the free ends of the left and right cantilever arms 
22 and 17. 
Each of the lower left and right arms 27 and 28 of the fastening portion 24 
of the register pin 11 has a threaded tap hole 29 and 31 respectively. 
These tap holes each carry a threaded set screw 34 or 36. A bottom portion 
of each set screw 34 or 36 is engageable with the bottom 18 of the 
insertion bar 3. The upper ends of the set screws 34 and 36 are accessible 
through elongated holes or slots 32 and 33 in the left and right 
cantilever arms 22 and 17 of the left and right holding devices 12 and 13. 
As may be seen in FIG. 3, the elongated slots 32 and 33 have sufficient 
length so that the set screws 34 and 36 can be engaged even if the 
register pin is slid all the way to the right or to the left. 
Rotation of the set screws 34 and 36 in a downward or clockwise direction 
will raise the lower left and right arms 27 and 28 of the fastening 
portion 24 of the register pin 11 upwardly against the undersurfaces of 
the cantilever arms 22 and 17 of the left and right holding devices 12 and 
13. The frictional forces between the engaging surfaces will hold the 
register pin in place. If the set screws 34 and 36 are backed off by being 
turned in a counterclockwise direction, the register pin 11 can be slid 
with respect to the holding devices 12 and 13. This sliding movement of 
the register pin 11 is limited by the spacing "a". In the preferred 
embodiment, the register portion 26 of the register pin has a thickness 
such that the register adjustment distance "s" is generally about 1 mm 
either to the left or to the right. 
Referring again to FIG. 1, it will be seen that the register portion 26 of 
the register pin 11 is generally in the shape of an upright T with the 
horizontal upper part or bar of the T extending generally in the direction 
of rotation of the plate cylinder 2. The transitions between the 
horizontal upper bar 37 and the vertical leg 38 of the T-shaped register 
portion 26 of the register pin are generally rounded or arcuate and are 
shaped to engage the surfaces of the rotatable parts of the plate fixing 
and clamping devices 4 and 6. 
A right upper register end 39 of the register portion 26 of the register 
pin is received in a register slot 41 on the leading edge of the printing 
plate, as may be seen in FIGS. 1 and 3. Similarly, a left upper register 
end 42 of the register portion 26 is received in a register slot 43 of the 
trailing or following edge of the printing plate 7. 
When the register pin 11 of the present invention is to be adjusted axially 
to thereby accomplish an axial adjustment of the printing plate 7, the set 
screws 34 and 36 are loosened. A gauge having the thickness of the desired 
adjustment amount is slid between the side surface of the register portion 
26 of the register pin 11 and the free end of either cantilever arm 22 or 
17. The register pin 11 can then be slid to the desired location and held 
in place by tightening of the set screws 34 and 36. 
While a preferred embodiment of an axially adjustable register pin in 
accordance with the present invention has been set forth fully and 
completely hereinabove, it will be apparent to one of skill in the art 
that various changes in, for example, the size of the plate cylinder, the 
length of the cylinder gap, the type of plate end clamping devices and the 
like can be made without departing from the true spirit and scope of the 
present invention which is accordingly to be limited only by the following 
claims.