Improvements in or relating to Cylinder Printing Machines.
Year: 1897

page_text: Date of Application, 30th July, 1897-Accepted, 4th Sept., 1897
COMPLETE SPECIFICATION.
Improvements in or relating to Cylinder Printing Machines.
JOSEPH KRAYER of Geisenheim on Rhine in the Empire of Germany, Manufac-
turer 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:―
Printing machines with oscillating cylinders are subject to the drawback that
superior class of work can only be printed by them in one colour as they do not
admit of doing high class work in many colours it being impossible to attain the
necessary exact registration of several colours with these machines. The reason
for this is that the printing cylinder does not always occupy exactly the same
position at the moment when the sheet to be printed upon is brought to it, but
according to circumstances comes to rest sometimes a few millimeters one side or
other of its average normal position, or in other words it changes its forward
motion into a return motion and vice versa. This variation is due to the fact that
moving masses possess a greater momentum when moving quickly than when
moving slowly and that therefore in counteracting this varying momentum there
are produced in the different parts of the machine according to the amount of said
momentum greater or smaller amounts of tension by the compression and therefore
the path traversed by the carriage, and by the cylinder connected to it by toothed
racks and wheels is sometimes greater and sometimes smaller than the normal.
In order to avoid such variations the present invention is designed to interrupt
the connection by rack and toothed wheel of the cylinder with the carriage at a
suitable moment in a way similar to that done in other machines by the so-called
disengaging fork, the only difference being that in other machines the cylinder is
kept at rest by the disengaging fork during the whole time of the return of the
carriage while in the machines with oscillating cylinders the fork becomes operative
according to the present invention only at the moment of the change of direction of
travel and this not for the purpose of giving the cylinder a longer period of rest but
of preventing the momentum of the machine produced by the quicker or slower
movement of the machine from having any influence on the position of the cylinder
at the moment of the change of travel and at the same time allowing the return of
the printing cylinder.
For this purpose the crank shaft a which causes the carriage E to reciprocate
in the ordinary well known manner is provided with two double eccentrics F1 F2.
These double eccentrics act on rods G G2 and these on one end of the forks H¹
and H respectively. The other bifurcated ends are adapted to engage with the
pins K, K on the printing cylinder, just before the cylinder completes its
oscillation in one or the other direction and owing to the form of the double
eccentrics F F brings the cylinder into its outermost position without the help
of the tooth rack and of the cylinder-wheel the teeth of which do not engage with
each other during this time and therefore do not exercise any influence on the
movement of the cylinder to the outermost position and at the beginning of the
return movement.
For this purpose the corresponding teeth on the tooth rack and on the cylinder

page_text: wheel are either altogether removed or made so much thinner that even when the
deviation from the normal length of travel of the carriage is the greatest the
teeth of the rack on the carriage and of the wheel on the cylinder do not come
into engagement and thus the irregularities of the length of the travel of the
carriage do not affect the position of the cylinder at the moment of the reversal
of motion whereby it is possible to bring the sheet to the cylinder at the moment
of reversing in exactly the same position and thus to effect a perfect register.
Having now particularly described and ascertained the nature of this inven
tion and in what manner the same is to be performed I declare that what I
claim is:-
1. In printing presses provided with oscillating cylinders in order to prevent
the influence of irregular movement of the machine on the position of the cylinder
at the moment of its reversal of motion the employment of a fork as H which at
a suitable moment drives the cylinder during the change of the latter's course its
movement being effected by means of an eccentric Fand rod G the engagement
of the carriage rack and cylinder gear being interrupted the fork also acting to
effect the commencement of the return motion of the cylinder substantially as
described.
2. The combination and arrangement of parts constituting the complete driving
nechanism for cylinder printing machines substantially as and for the purpose
described and illustrated in the accompanying drawings.
Tatad this 07h
fT.... 1007
BOULT & WADE,
Agents for the Applicant.