Improvements in Lithographic Printing Presses.
Year: 1895

page_text: Date of Application, 19th Jan., 1895
Complete Specification" Left, 19th Oct., 1895 Accepted, 23rd Nov. 1895 ....
PROVISIONAL SPECIFICATION.
Improvements in Lithographic Printing Presses.
I THOMAS GEORGE DUNN, of 42 Peel Street, Hull, in the County, of York,
Gentleman, do hereby declare the nature of this invention, to be, as follows:-
The object of my invention is to produce a lithographic printing press. which
hall dispense with the ordinary boxwood or other scraper, and considerably
educe the wear on the tympan, and also the amount of power required for getting
the pressure on the stone, and at the same time raise the stone bed and obtain an
even pressure throughout, which is impossible with the present construction of
lithographic printing press.
I construct my invention as follows:
`I dispense with the ordinary, scraper mounted in a frame, and insert in the place
a suitable roller, this roller is mounted in such a manner that the pressure is
obtained direct over the centre, the ends .being loose and working loosely in
bearings on the frame of the press.
To the dever axle which is underneath this roller I attach a cam or projection to
which is connected a lever, such lever being attached or pivotted to a bracket in
which one or more rollers work, the stone bed bearing upon such rollers: On the
end of this bracket nearest to the lever axle, I employ a small bracket having a
slot through the back and a hole at the bottom, a threaded pin with an enlarged.
end passes through the bottom hole where a nut is screwed on, a bolt passing:
through the lever, the enlarged head of the pin, and through the slot at the back,
this allows of the lever attached to the bracket and projection on the axle being;
raised and lowered to suit the height of the stone bed...
1:
A small bracket-in which a roller is mounted; is arranged on the front of the
frame, the pivotted bracket or arms having deepened sides, when these deepened:
parts come to the roller mounted in such small bracket, the said pivotted bracket
or arms are lifted and come in contact with the underside of the stone bed which
slides easily backward and forward on the rollers or antifriction runners mounted.
upon the said pivotted bracket or extended arms.
:
A small runner. may be employed for the stone to rest upon when it passes the
▸ centre.
1005
Savile Street, Hull, and: Crossley Street, Halifax,: :
Agent for the. Applicant.
COMPLETE SPECIFICATION:
Improvements in Lithographic Printing Presses:
..
...THOMAS GEORGE DUNN, late. of 42 Peel Street, but now. residing at
51Springi Bank;.:both in Hull, in the County of Yorks, Gentleman, do hereby
declare the nature of this invention, and in what manner, the same is to be.
performed to be particularly described and, ascertained in and, by, the following
statement :-
• Twalchiest of my invention is to produce a lithographic printing press, which

page_text: shall dispense with the ordinary boxwood or other scraper, and considerably
reduce the wear on the tympan, and also the amount of power required for getting
the pressure on the stone, and at the same time raise the stone bed alike at both
ends and thus obtain an even pressure throughout, which is impossible with the
present construction of lithographic printing presses.
DESCRIPTION OF DRAWINGS.
Fig. 1. shows front view of lithographic printing press with my improvements
applied, with front of the frame, lifting lever, and roller handle removed to show
such improvements.
Fig. 2. is a plan view of lever axle with the cam and pivotted bracket mounted
thereon:
Fig. 3. shows end-view of Fig. 1, left hand side, but with frame intact and with.
lifting lever and roller handle.
I construct my invention as follows :—
I dispense with the ordinary scraper mounted in a frame, and insert in its place
a suitable roller A, this roller is mounted so that the pressure is obtained-direct
over the centre, and' applied by means of threaded spindle A', and hand wheel. A²,
the ends of the said roller being loose and working loosely in bearings B, on the
frame C of the press.
+
To the lever axle D, which is underneath this roller, I attach a cam or
projection E, at or near the centre of such axle, to which is connected a lever or
levers 'F, such lever or levers being attached or pivotted to a bracket G, in which
one or more rollers or antifriction runners H work; the stonebed. J. bears upon such
rollers wheu 'in use. On the end of this bracket nearest to the lever axle: I employ
a small bracket K, having a slot L through it, a pin or bolt M-passes through the
slot L, a nut being screwed on, the bolt also passes through, the lever' or levers F,
this allows of the lever or bracket G being regulated, so that by means of the
projection or cam E on the axle, it can be raised and lowered to suit the height of
the stonebed J. A small bracket N in which a roller O is mounted, is arranged
on'the front of the frame C, the pivotted bracket or arms G, having deepened
sides, when these deepened parts come to the roller O mounted in such small
bracket N, the said pivotted bracket or arms are lifted, and come in contact with
the underside of the stone bed J, which' slides easily backward and forward on the
rollers or antifriction runners H, mounted upon the said pivotted bracket or
extended arms G.
A small runner P may be employed for-the stone-bed to rest upon after passing
the centre.
In the ordinary construction of lithographic printing presses a scraper of
boxwood or the like is arranged in the centre of the machine above the stonebed J,
this scraper is lowered 'to be'in 'contact with the tympan or leather covering Sof
the "said stonebed, the roller T being raised by means of a projection U on the
lever axle D, underneath, coming in contact with the bearings V, in which such
roller T is mounted; as the lever W, Fig. 3, is drawn over this projection raises
the bearings V, which lifts the roller T, so that the stonebed J is raised or lifted
most of its length off the ridge or flange X. on which it rests, as the handle Y,
Fig. 3, of the roller T, is turned, such roller revolves and the stonebed J moves
along from one end of the machine to the other, the scraper putting the pressure
on the tympan and stone by means of which the copy from the stone is taken,
when the centre of the stone bed is passed the scraper and the roller T, its end
tilts over and moves on the flange. X, there not being a level surface for it to move
on, the friction caused by the scraper and also by the ends of the stone bed J,
moving on the flange X, is considerable; it often requiring two 'ment to turn the
handle Y to work the machine.
:
With my improvements the labour of working the machine is considerably
reduced, there being little or no friction. The roller T is still used for moving the

page_text: stone bed J, and also the lever W. with axle having projection U, for raising such
rollers, but now when the lever W is pulled over to lift the roller T, it at the same
time brings over the cam E, which is mounted on it, this cam by means of levers F
and small bracket K, raises the bracket G, and thus brings the antifriction
runners H to the same height as the roller T, by this means providing a level
frictionless surface for the stone bed to move on, the roller P receiving it when it
passes the centre, at the same time the roller A entirely obviates wear and tear on
the tympan S, there being no friction on it as the stone bed J is moved along.
These improvements are applicable to the various constructions of lithographic
printing presses, but may require a slight modification to suit the frames of some
of them.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:
1. In lithographic printing presses, the employment of a roller A in place of the
ordinary boxwood or other scraper, such roller being mounted in bearings B in the
frame C, of the press, in the manner and for the purposes substantially as shown
and described.
2. In lithographic printing presses, the employment of a bracket G, in which
are mounted antifriction runners H, such bracket being attached by a lever or
levers F, to a cam or projection E, mounted on the lever axle D, with or without
regulating bracket K, and with rollers O and P, in the manner and for the purposes
substantially as shown and described.
Deted this Fichteenth
of October 1805
JOHN E. WALSH,
Crossley Street, Halifax, and Savile Street, Hull,
Patent Agent for the Applicant.