IMPROVEMENTS IN MACHINERY FOR ENGRAVING PRINTING ROLLERS
Year: 1876

page_text: PROVISIONAL SPECIFICATION left by David Fulton at the Office of the
Commissioners of Patents on the 7th December 1876.
DAVID FULTON, of the Duke Street Engraving Works, Glasgow, in the County
of Lanark, North Britain. "IMPROVEMENTS IN MACHINERY FOR ENGRAVING
PRINTING ROLLERS."
This Invention relates to machinery for engraving printing rollers by means of
small steel milling rollers, and has principally for its object to secure rapidity and
accuracy of operation by automatic means in cases in which the action of the
milling roller is interrupted, in order that the device which it indents or engraves
may be applied to separate spaces.
Heretofore in attempts to attain the results now aimed at the printing roller has
been made to rotate continuously at a uniform rate, the milling roller being raised
from and lowered down upon the printing roller by means of an eccentric or cam,
but such mode has failed to give sufficient accuracy, and the desired results have
had to be approximated to by very careful, skilful, and tedious manipulation of the
machinery.
By the present Invention the printing roller is driven intermittently, and is
brought completely to rest between each action of the milling roller. The space on
the printing roller on which the milling roller acts at each operation is determined
by a cam or eccentric which lifts the milling roller, and the interval unacted on, if
any, is determined by the extra extent of the movement of the printing roller
beyond the point at which the milling roller is lifted. The printing roller is then
stationary for a sufficient time, during which the milling roller redescends upon it
and must come in contact with it in the precise position required, so that on the
printing roller moving forward again the milling action starts accurately as
desired.
After each action, and whilst the printing roller is completing its extra movement
corresponding to the part to be unacted on, the milling roller is turned back to its
proper position for starting by a weighted lever attached to it, and provided with a
striking point to encounter a stop, the striking point being adjustable by a screw
so that the proper position of the milling roller may be accurately secured.

page_text: The printing roller is carried in a usual manner in the machine, and is turned by
a train of toothed wheels which can be changed to suit different sizes of rollers and
other circumstances.
The intermittent motion is obtained, according to one modification, by means of a
pair of wheels, the driving one of which has a part of its rim toothed, and a part
plain or untoothed, the latter part corresponding to the period during which the
printing roller is stationary. The driving wheel is formed with one or more series
of teeth to gear with the teeth of the driver, and with a very short blank space
between the end of one series and the beginning of the next; and the sets of teeth
are brought to gear successively with each other by single larger teeth fixed in
suitable positions at the sides of the rims having the small teeth. Instead of the
wheels just described, what are known as Swiss wheels or any other known arrango-
ment for giving a suitable intermittent motion may be adopted.
The milling roller may be carried as in any suitable arrangement of existing
machinery for continuous milling work, but it is by preference held by a lever
centered on a bracket or standard formed on or attached to the longitudinally
sliding carriage, such lever having on the back or further side of its fulcrum an
arm connected by a link to a weighted lever below, an arrangement more convenient
and less in the way of the attendant worker than that ordinarily adopted. The
cam or eccentric by which the milling roller is lifted off the printing roller is by
preference arranged to act on the lower weighted lever.
It is an important advantage of the herein-before described improvements that
the operation known as "rocking," by which the indenting action of the milling
roller is repeated when required, can be performed without in the slightest degree
interfering with the accuracy or rapidity with which the work may be continued
between the rocking operations.