Improvements in Lithographic Printing Machines.
Year: 1899

page_text: Date of Application, 17th Jan.,
1899
Improvements in Lithographic Printing Machines.
I, DANIEL THOMAS POWELL, of 33A, Ludgate Hill, in the City of London,
Printers' Engineer, do hereby declare the nature of this invention to be as
follows:-
**
This invention relates to improvements in lithographic printing machines and
has for its object the simplification of the method of operating the stone-box
and enabling the machine to be driven at a higher speed than has heretofore
been attainable. It is more particularly applicable to small machines. The
stone-box with ink-table and damping board is mounted on one or more
rockers"
attached to a shaft having bearings in the bottom of the side frames and these
"rockers" are of such a length that the stone-box travels to and fro a sufficient
distance without losing its balance consequently it may be rocked to and fro at
a very considerable speed without jar or vibration. The " rockers are moved
to and fro by a connecting rod worked from a crank pin in spur wheels in the
ordinary well known manner.
39
The stone-box in its travel to and fro necessarily describes a portion of a circle.
The stone being flat, the cylinder must rise and fall, following the positions taken
by the stone.
To accomplish this the cylinder is set in bearings which are not attached to
the side frames as is customary but are provided with spindles working in guides
in the side frames and carrying impression blocks & wheels which latter bear
against shapes" fixed on the under side of the stone-box.
tracks"
The cylinder is maintained at its proper height above the stone-box by means
of wheels on the cylinder shaft running on
on the stone-box. With
the exception that the ink table and damping board are curved and the frame of
the machine circular shape to correspond with the radius of the rockers" and
stone-box the machine works much the same as an ordinary lithographic machine.
Dated this 16th day of January 1899.
Improvements in Lithographic Printing Machines.
I, DANIEL THOMAS POWELL, of 33A, Ludgate Hill, in the City of London,
Printers Engineer, do hereby declare the nature of this invention and in what
[Price 8d.]

page_text: manner the same is to be performed, to be particularly described and ascer
tained in and by the following statement:-
-
This invention relates to improvements in lithographic printing machines and
has for its object the simplification of the method of operating the stone hox
and enabling the machine to be driven at a higher rate of speed than has hereto-
fore to attainable. It is more particularly applicable to small machines.
In order that my invention may be clearly understood I have annexed hereto
a sheet of drawings with indicating letters to point out the various parts and in
each figure the same letters indicate like parts.
Fig. 1 is a side elevation and gives a general view of the more important
parts of the whole machine.
Fig. 2 is a detail of the stone box, rockers, and impression arrangements.
A flat stone is used and the stone box A is mounted on one or more rockers B
which has its bearings at the bottom of the side frame. These rockers are
moved to and fro by rod in connection with spur wheel and crank pin in the
ordinary well known manner.
D is the printing or impression cylinder fitted with grippers or other device
for taking the sheets from the laying on board. This cylinder has its axis on
the bearings E which are distinct from the side frames and are provided with
impression spindles F held in position by the guides in the side frame G & G
H shows the impression block which carries a studpin which projects through a
slot in the sideframe, from the outside to the inside of the frames, and on this
stud is placed the friction or impression wheel J which is adjusted by check-
nuts and P so as to make contact with the shape or camb Q attached to the
under side of the stone box. It is convenient to place a spring R beneath the
impression block H to make allowances for inequalities of the lithographic stone,
the lower check nut P in such case controls the tension of the spring and from
it the impression is obtained. If perfect level stones are assured the spring
might be dispensed with.
The motion of the cylinder is obtained by a means of a well known arrange-
ment of a loose wheel on the cylinder and a rack on the stone box as shown
at L L (Fig. 2).
It will be seen that this rack is curved at either end and is straight in its other
part. The ink table M is preferably curved and the damping table S is also
preferably curved and both of these are attached to the stone box or the rockers.
In its traverse of the full stroke from end to end by reason of its position on
the rockers, the stone box presents always varying angles to the cylinder and
in order that the cylinder may bear evenly on the flat surface of the stone it is
necessary that it should rise and fall to conform with the varying angles and this
is provided for the shape or camb K and the friction wheels and the other
parts already described which controls them. The impression is obtained by
means of the friction wheels J and the impression block H with the check
nuts OP with or without the spring R.
"
To prevent the cylinder dipping I provide on the cylinder shaft and of the like
diameter with the cylinder carrying wheels" which run on tracks" placed at
the side of the stone box in order that it may be maintained at its proper height
above the stone box. The stone box placed on the top of the rockers as set forth
may be used with equal advantage in a machine wherein the stone is curved to
the radius of the circle described by the motion indicated and it may also be used
in conjunction with a curved bed, whereon are placed prepared plates of zinc,
aluminium, or other suitable material which are sometimes used in the place of
lithographic stones.
In either of such cases the rising and falling of the cylinder would be un-
necessary and consequently the motions to obtain this would also be unnecessary.
The cylinder then would be mounted in fixed bearings in the ordinary well
known manner & with or without springs.

page_text: In other respects the machine works in a like manner with the well known
lithographic machines.
Having now particularly ascertained the nature of my said invention and in
what manner the same is to be performed, I declare that what I claim is:-
1. In a lithographic machine, the introduction, adaptation, and use of a stone
box, either flat or curved, mounted on a rocker or rockers substantially as
described.
2. The combination of the stone box A, the rockers B, the impresssion spindles F,
carrying the bearings E, the guides G & G¹, the impression blocks H, the im-
pression wheel J, the checknuts OP, the spring R, the shape K and curved
rack L together with the wheels and tracks substantially as and for the purposes
described.
This 101
Ontation 1900