IMPROVEMENTS IN THE LITHOGRAPHIC PRESS
Year: 1852

page_text: PROVISIONAL SPECIFICATION left by Frederick Dangerfield at
the Office of the Commissioners of Patents, with his Petition,
on the 13th December 1852.
(Void by reason of notice to proceed not having been given within
the time prescribed by the Act.)
I, FREDERICK DANGERFIELD, of the firm of Ashbec and Danger-
field, of Broad Court, Long Acre, in the City of Westminster,
Lithographers, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE LITHOGRAPHIC PRESS " to be as follows:-
These improvements consist chiefly, 1st, in dispensing with the
use of the lever for obtaining or removing the pressure. 2nd. In
taking the impression by the reverse action of the bed of the press,
or when it is being returned to its place. In the presses now in
use, the impression is obtained during the forward action of the bed.
3rd. In the bed of the press running throughout on its bearers, and
not rising from the slides to meet the pressure. 4th. In the
cylinder working with two cog wheels and a winch, thus obtaining
the reverse motion of the bed by the forward movement of the
handle of the press, and so preventing the necessity of the workman
moving from his place.
.These improvements effect an increased celerity in the rate of litho-
graphic printing, and also reduce the amount of labour requisite

page_text: for working. The use of the lever for obtaining or removing
the pressure is abolished by making the box in which the scraper
is fixed, work in moveable sides, which, together with the bridge
forming the top of the press are suspended to the sides of the
press by means of springs. The pressure, which is self-adapting
is gained in this Invention by sliding rests working in grooves
in the bed of the press, which rests can be fixed to the greatest
nicety; and the method of working it is by forcing the bed of
the press in beneath the bridge, until the rest have passed under
the suspended sides, when, by withdrawing the bed to its former
position, the rests by catching the sides forces the scraper perpendi-
cular, in which position it is retained, the rests then passing clear
of the sides and the pressure continuing until necessary to be
removed. The bed of this press is lengthened for the purpose of one
end resting on the cylinder, and along.both sides of bed of the press
and underneath it a row of cogs are fixed, which work in cog
wheels attached to the cylinder within the sides of the press; and
outside a cog wheel, likewise affixed to the cylinder, works in
another attached to a spindle, to which a winch for the purpose of
working is secured. In this Invention the tympan is made self-
acting by means of a cord, which being attached to it is led through
pulleys over the back of the press, and passing beneath it is fastened
to the outer end of the bed farthest from the cylinder. By this
means the tympan works down or up with the forward or backward
movement of the bed to which it is attached. It should be stated
that the tympan frame in this Invention does not work on hinges
attached to it, as in the press now in use, but the frame is fixed to
a moving cross piece, which works in uprights fixed on either side
of the end of the bed nearest to the cylinder. And again in this
Invention the use of blocks for retaining the stone in its proper posi-
tion is dispensed with, by means of a moveable stay working in the
same grooves with the rests before mentioned.