IMPROVEMENTS IN LITHOGRAPHIC PRESSES
Year: 1884

page_text: I, AISIK SCHAPIRO, of 20, Jüden Street, Berlin in Germany, do hereby declare
the nature of said Invention for IMPROVEMENTS IN LITHOGRAPHIC PRESSES to be
as follows:-
This Invention has for its principal object to automatically vary the pressure on
the printing surface of a lithographic stone, while the latter is drawn through the
press. For this purpose I provide the underside of the table on which the stone
rests, or the upper side of the stone itself with an inclined or wedge shaped surface
or surfaces, or I use an eccentric roller or rollers for lifting the table while it is
being drawn through the press.
As long as the roller or rollers supporting the table are in contact with a
horizontal and thin portion of the latter, the pressure remains at a constant
minimum, but when they arrive at the inclined portion (where the table becomes
thicker) the table is lifted and the pressure increased until it has reached its
maximum, when the roller is in contact with the thickest part of the table.
The roller and table may be geared together, or they may simply adhere by
friction.
If an eccentric supporting roller is used with which the table is in direct contact,
the roller and table should be geared together, and where a cylindrical roller is
placed between the table and the eccentric roller, the latter should be geared
together with the intermediate roller. In either case the table will fall and rise
according to the radius of the eccentric roller.
The roller or curved bar which comes in contact with the upper side of the stone,
while it is being drawn through the press, is made vertically adjustable indepen
dently of the supporting roller, and may be pivoted on a horizontal shaft, which
allows the bar to turn sideways and be set out of action when the stone is drawn
back ward, while it is arrested by an adjustable stop and held upright when the
stone is drawn forward. Either the upper press-beam, the stone, table, or roller
mechanism is provided with an elastic lining in order to render the pressure
elastic.
The pressing board generally used for lithographic printing and fixed to the
required position by a lever or screw at the beginning of the operation, is in the

page_text: improved press held by a frame mounted on two pivots resting in open bearings on
the table.
This frame has two arms which come in contact with the fixed cross-beam after
the stone has been rolled through, whereby the frame is turned on its pivots
and the pressing board lifted out, after which the printed paper can be casily
removed.
During the forward motion of the stone, the frame is turned down again by its
contact with the curved bar or rubber.

page_text: I, AISIK SCHAPIRO, of 20 Jüden Street, Berlin, in Germany, do hereby declare
the nature of said Invention for "IMPROVEMENTS IN LITHOGRAPHIC PRESSES,"
and in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement:-
This Invention has for its principal object to automatically vary the pressure on
the printing surface of a lithographic stone, while the latter is drawn through
the press.
In describing the Invention reference will be made to the accompanying
Drawing, Figs. I. to VI.
The improvements in the process of printing by means of lithographic presses
hereinafter differ from the printing process hitherto known in as much as the
operation of imparting pressure necessary for each separate impression and the
operation of suspending the pressure after the impression is completed, are omitted.
The new lithographic printing process is characterised:
1. By an arrangement by means of which the pressure device (roller, curved bar
or similar device) is adjusted only once.
2. By automatically imparting pressure respectively suspending the same before
and after the impression is made.
3. By the mechanisms for automatically imparting and suspending the pressure
based on the application of a wedge or excentric as pressmechanism.
The pressmechanism is represented in 4 modifications in Figs. I. to IV. Fig. I.,
represents a lithographic stone tapered at its pressure surface. The sloping a serves
as pressmechanism and at the same time for suspending the pressure. This simple
and extraordinarily effective and practical means of a tapered surface of the stone
is new and causes a pressure hitherto hardly obtained by the most complicated
devices.
By the application of this wedge-shaped surface the separate operations of
imparting pressure and suspending the same is entirely omitted and the printing
process is thus substantially simplified the operation then only consisting of drawing
the stone through the press during which the pressure is automatically imparted
and suspended.
The complicated arrangement for imparting pressure is thus entirely omitted and
replaced by a simple adjusting device, screw 6 Fig. I.-(or any other well known
adjusting device such as an excentric or a similar device),-which serves to adjust
the curved bar r or pressing roller at the proper height so as to be brought in
contact with the sloping surface near the point a.
During the drawing of the stone through the press the pressure gradually
increases until it reaches its maximum on the horizontal surface of the stone.
During the passage of the stone the impression takes place in the usual manner and
the curved bar r reaches the wedge shaped or tapered surface a at the other end of
the stone whereupon the pressure gradually decreases until the stone is completely
released.
One adjustment of the upper press-beam p which either carries the curved bar
or a roller is therefore sufficient for printing a long time. The advantages thus
obtained are: A simplified arrangement for imparting pressure and simplified
operation of printing.
Instead of making the ends of the stone wedge-shaped, the table or carriage k
may be made wedgeshaped, a a Fig. II.

page_text: '
In order to facilitate the working, the curved bar r is arranged so as to oscillate
and provided with a stop p¹ its edge thus describes a segment which also forms a
gradually diminishing wedge shaped surface which produces during the passage of
the stone from the right to the left a corresponding pressure on the stone while
during the passage in the opposite direction the curved bar is turned sideways that
is to say set out of action and loosely passes over the stone.
The curved bar r may be so adjusted by the screws that it cannot pass over the
vertical position in which it exerts the greatest pressure on the stone.
It is clear that with the curved bar thus arranged to turn sideways from the left,
see Fig. II., the pressure may be imparted from one side only while towards the
opposite side the curved bar is set out of action. For the purpose of printing
from the left as well as from the right two curved bars adapted to be set out of
action in the opposite direction, are used.
The bars thus constructed may be replaced by a roller Fig. I.
The inclined wedge shaped surface may be arranged at the lower rolling
mechanism by arranging the lower roller u so that it can be lifted and by causing
a wedge-shaped surface to act on the same from below.
This wedge shaped surface is preferably obtained by the excentric roller t
situated under the roller Fig. IV., and which is slightly excentric at s¹ but
otherwise centric.
The roller u imparts motion to the excentric roller t through friction (or through
a separate gearing ¹z during which the roller u is slightly lifted whereby the
curved bar (or roller) which has been previously adjusted exercises the necessary
pressure on the stone.
The dimensions of the excentric roller t must be so that the passage of the stone
'corresponds to /, of a revolution of the excentric roller; after the passage of the
stone the opposite excentricity s¹ begins to act, the pressure gradually decreases
'and after the complete passage the stone is free.
The further progress sideways of the stone can take place without interfering
with the stone because the slight lifting which again takes place has no effect on
the stone.
As represented in Fig. V. the roller u¹ itself may be made excentric and the
wedge shaped surface may thus be directly applied, in which case the table and the
roller u must be connected by gearing.
The roller u must of course be of such a size that its circumference corresponds
to the length of the stone.
The modifications represented in the Drawings represent the principal arrange-
ments of the wedgeshaped surface forming the printing mechanism and they may
be suitably modified in combination with each other.
It should further be observed that with my mode of printing the pressure
exercised should be elastic, notwithstanding the rigid pressure-mechanism of the
wedgeshaped surface, for which purpose one or more of the acting parts, such as
the upper press beam, the stone or the lower roller must be provided with an elastic
covering.
In the arrangement represented by Fig. II. the printing process is carried out by
means of an inclined surface and a curved bar adapted to turn sideways so as to be
*set out of action. This mechanism works as follows: The printing takes place
from the right; the stone is drawn through the press until it arrives on the right
hand inclined surface a whereupon the rubber is set out of action.
Subsequently the stone is drawn back during which the bars loosely slide over
the stone after which the impression is removed on the right.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what
-I claim is:
i
:
1. In lithographic printing presses the mode of adjusting the press-mechanism
once (for any number of impressions) and the arrangement for automatically

page_text: imparting and suspending the pressure at each impression by means of a wedge
shaped or excentric surface.
2. The application of a wedge-shaped surface to the table or carriage, to the
stone or to any other acting part of the machine for the purpose of imparting
pressure without separate adjusting mechanism, and in rotary press mechanisms
replacing the wedge shaped surface by an excentric surface.
3. The application as press mechanisin of a curved bar or roller mounted on
hinged bearings and adapted to turn sideways when required to be set out of
action.
4. The combination of the mechanism set forth in claim 2, with the arrangement
set forth in claim 3.
All substantially as described and illustrated and for the purposes set forth.
Dated this 24th day of September 1884.
AISIK SCHAPIRO.
By Herbert & Co.,
Agents, 67 Strand.