New or Improved Impression Adjuster for Platen Printing Machines.
Year: 1891

page_text: Date of Application, 15th Apr., 1891
Complete Specification Left, 15th Jan., 1892-Accepied, 20th Feb., 1892
PROVISIONAL SPECIFICATION.
A New or Improved Impression Adjuster for Platen Printing
Machines.
I SAMUEL WILLIAM NORTH of 8 Rosebank Road, Belle Vue Road Leeds
in the County of York Letter Press Machinists Foreman do hereby declare the
nature of this invention to be as follows:-
My invention refers to means for adjusting the pressure between the platen and
frisket of platen printing machines, and is applicable to all such machines in which
the platen is drawn towards the frisket by means of connecting rods. Usually two
connecting rods are employed, one attached to each side of the platen. The
opposite ends of these connecting rods are fitted on the eccentrically turned ends
of a cross-shaft, which connects these ends of the two connecting rods. The back-
ward and forward motion is imparted to this cross-shaft by means of the bearings
which carry it, these latter being actuated by various mechanism (according to the
construction of the printing machine) from the main driving shaft. The con-
necting rods transmit this backward and forward motion to the platen from the
cross shaft.
It will be evident that by rotating the cross shaft in its bearings, the
effective distance between the centres of this cross shaft and the centres of the
platen pins, to which the platen ends of the connecting rods are attached, is
altered, or in other words the effective length of the connecting rods is altered.
By this means the pressure of the platen against the frisket may be adjusted,
that is when the cross shaft is partially rotated in the one direction the effective
length of the connecting rods is increased, so that the pressure of the platen
against the frisket is lessened, or it may even be taken off altogether whilst
if the cross shaft is partially rotated in the opposite direction, the effective
length of the connecting rods is decreased thereby increasing the pressure of the
platen against the frisket.
:
In the above description the movement of the platen towards the frisket is
supposed to take place by a pull in the connecting rods, the mechanism however
is applicable where the same movement is caused by a thrust in the connecting
rods.
The partial rotation of the cross shaft to effect the impression adjustment, is
made by moving a lever attached to one end of the cross-shaft. In order to
be able to adjust the effective length of the connecting rods, and consequently
also the pressure between the platen and the frisket to a much greater nicety
or accuracy, mount this lever loosely on the cross-shaft, and close to the lever
I ker or otherwise securely fix a collar to the cross shaft. This collar is pro-
vided with a projecting tongue piece, which is situated between two side pieces
or prongs of the loose (forked) lever. Through each of these side pieces a set
screw is passed, and these are screwed in so as to hold the tongue piece between
their inner ends. It will be evident that by screwing one of the screws further
in and slackening the other out to a corresponding extent, that the partial rotation
of the cross-shaft and consequently the effective length of the connecting rods, and
thereby also the pressure of the platen against the frisket can be almost imme-
diately and to an extremely fine degree adjusted.
Dated thi. 1461 days 1901
J. CLARK JEFFERSON,
2, East Parade, Leeds, Agent for Applicant.

page_text: COMPLETE SPECIFICATION.
A New or Improved Impression Adjuster for Platen Printing
Machines.
I SAMUEL WILLIAM NORTH of 8 Rosebank Road, Belle Vue Road Leeds
in the County of York Letter Press Machinists Foreman 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:—
The
My invention refers to means for adjusting the pressure between the platen and
carriage of platen printing machines, and is applicable to all such machines in
which the platen is drawn towards the carriage by means of connecting rods.
Usually two connecting rods are employed, one attached to each side of the
platen. The opposite ends of these connecting rods are fitted on the eccentrically
turned ends of a cross shaft, which connects these ends of the connecting rods. The
backward and forward motion is imparted to this cross shaft by means of the
bearings which carry it, these latter being actuated by various mechanism, (according
to the construction of the printing machine), from the main driving shaft.
connecting rods transmit this backward and forward motion to the platen from the
cross shaft.
It will be evident that by rotating the cross shaft in its bearings,
the effective distance between the centre of this cross shaft and the centre of the
platen pins, (to which the platen ends of the connecting rods are attached), is
altered or in other words the effective length of the connecting rods is altered.
By this means the pressure of the platen against the carriage may be adjusted;
that is when the cross shaft is partially rotated in one direction, the pressure of
the platen against the carriage is lessened or it may even be taken off altogether;
whilst if the cross shaft is partially rotated in the opposite direction, the pressure
of the platen against the carriage is increased.
In the above the movement of the platen against the carriage is supposed to
take place by a pull in the connecting rods; the mechanism however is applicable,
where the same movement is caused by a thrust in the connecting rods.
The partial rotation of the cross shaft to effect the impression adjustment is
made by moving a lever attached to one end of the cross shaft. In order to be
able to adjust the effective length of the connecting rods and consequently the
pressure between the platen and the carriage to a much greater nicety or accuracy,
I mount this lever loosely on the cross shaft, and close to the lever I key or other-
wise securely fix a collar to the cross shaft. This collar is provided with a pro-
jecting tongue piece, which is situated between two side pieces or prongs of the
loose forked lever. Through each of these side pieces a set screw is passed, and
these are screwed in so as to hold the tongue piece between their inner ends. It
will be evident that by screwing one of the screws further in and slackening the
other out to a corresponding extent, that the partial rotation of the cross shaft
and consequently the effective length of the connecting rods and thereby also the
pressure of the platen against the carriage can be almost immediately and to an
extremely fine degree adjusted.
And in order that my invention and the manner in which the same is to be
performed may be clearly under-tond, reference is given to the accompanying sheet
of drawings and to the letters and marks thereon, in which :-
Fig. 1. is a side elevation, and Fig. 2 is a cross section illustrating my invention.
is one end of the cross shaft, which fits in bearings cast on the platen frame.
c is the extreme end of this cross shaft, which is formed or turned eccentrically
with respect to the main part of the cross shaft. The extreme opposite end of the
cross shaft is similarly eccentrically placed or turned. On these two eccentric
ends fit the corresponding ends of the above mentioned connecting rode d. e is
the before mentioned lever, loosely mounted on the cross shaft a and provided with
prongs or side pieces is the collar, keyed, or as shewn in the drawing,

page_text: securely fixed in position on the cross shaft by a set screw h recessed into the cross
shaft is the tongue piece formed on the collar g and placed between the side
pieces and k are set or adjusting screws, passing through the side pieces f
and by means of which the cross shaft a can be partially rotated. The rough
adjustment is performed by hand, by throwing over the lever e to the notch or m.
By throwing it over to the former, the effective length of the connecting rods is
shortened; and when to the latter, the effective length of the connecting rods is
increased, and this is usually thereby so much lengthened, that the platen and
carriage do not come in contact. The pressure between the platen and carriage,
when the lever e is thrown into the notch 1, is more accurately and finely adjusted,
by my invention, by means of the set screws ; and ; ; being slackened and
A screwed up to increase the pressure, whilst k is slackened and screwed up
reduce the pressure.
to
It is immaterial to my invention whether the cross shaft is connected with the
platen or carriage ends of the connecting rods.
It will be evident that with my invention, there is no risk of the cross shaft
slipping round relatively to the fork lever, as is the case when the adjustment is
made by slackening back and then tightening the set screw h, which in machines
as hitherto constructed cannot be recessed into the cross shaft, or if recessed the
fineness and accuracy of the adjustment is limited.
It will also be evident that my invention is not materially altered, if the side
pieces are formed on the collar g, and the tongue piece i on the lever e.
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
1° The improved impression adjuster for platen printing machines consisting
of the cross shaft a with eccentrically turned ends c, the collar g provided with a
tongue piece (or two side pieces), and the lever with side pieces ☐☐ (or
tongue piece), the side pieces being provided with adjusting screws and k, sub-
stantially as herein set forth.
リ
2° In impression adjusters for platen printing machines, the hinged lever e
provided with side pieces ff (or tongue piece ), and the collar
with tongue
piece (or side pieces ff), the side pieces being provided with set screws ; and k,
substantially as and for the purpose herein set forth.
3° The improved impression adjuster for platen printing machines substantially
of the construction herein set forth and illustrated in the accompanying drawings.
Dated this 14th day of January 1892.
J. CLARK JEFFERSON,
2, East Parade, Leeds, Agent for Applicant.