IMPROVEMENTS IN PENTAGRAPH ENGRAVING MACHINES
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by the said John Mowat at the Office
of the Commissioners of Patents on the 14th December 1882.
JOHN MOWAT, of Barrhead, in the county of Renfrew, North Britain,
"IMPROVEMENTS IN PENTAGRAPH ENGRAVING MACHINES,"
This Invention, which relates to improvements in pentagraph engraving
machines, has special reference to novel means or appliances for varying the extent
of motion of the roller or cylinder being engraved, to compensate for irregularities*
in the diameters of different rollers or cylinders employed.
It is essential in engraving the copper or steel cylinders used in calico printing
and for similar purposes, that the "repeat" of the pattern engraved should fit
within the circumference of the cylinder, and in the class of pentagraph engraving
machines in which engraving diamonds only traverse in one direction while the
formation of the pattern is completed by the rocking motion or partial rotation
of the cylinder, it has been hitherto only possible to adjust the levers of the
pentagraph to a slight extent for this purpose, and that without securing precision
in fitting in the pattern to suit different diameters of cylinders. The present'
improvements, which are designed to overcome this difficulty, consist in forming
the supporting and actuating discs, which carry and rock or partially rotate the
cylinder or roller being engraved, with bevilled edges, or in the form of frustra of
cones or of stepped cones, decreasing in diameter at their inner faces, so that the
position of the cylinder or roller on the discs may be adjusted towards or from the
centre of the discs, and consequently the extent of motion of rotation of the
cylinder in relation to that of the discs may be varied. For this purpose also the
cylinders are turned at their ends to fit the bevilled edges of the carrying discs,
which may be roughened or serrated, and these discs are fitted to slide on their
carrying shaft, so that they can be adjusted at a greater or less distance from
each other. This lateral adjustment, which admits of the copper cylinder being

page_text: supported on the bevilled or stepped faces of the discs at a greater or less distance
from the centre of the disc shaft, may be effected in different ways. In a
convenient arrangement the boss of each disc is provided with a pinching screw to
secure it to its shaft, and a screwed sleeve is fitted and secured on the shaft
outside the boss, and is fitted with a screw nut, which may be screwed out or in to
bear on the end of the boss, and prevent any further lateral motion after the discs
are set in the desired position.
In order to relieve a portion of the weight of the copper cylinder from the
bevilled edges of the carrying discs, and thereby prevent undue abrasion of the
turned ends of the cylinder, an adjustable segment is fitted to the inner side of
each disc, and is caused to bear on the cylindrical surface of the cylinder. The
segmental piece is fitted to slide on a block fixed to the disc, and the adjustment of
the segment, to suit different diameters and positions of the cylinder, is effected
by means of a screw connecting the sliding segment and block.
The ends of the shaft, on which the cylinder or roller is mounted, are carried in
the usual bush bearings, and the bushes are fitted to slide vertically. The
adjustment of these bushes to correspond with the adjustment of the position of
the cylinder, is effected either by means of screws passed through the bearing
brackets and bearing on the under side of the bushes, or by wedges or similar
devices passed inwards or outwards below the bushes by screws.
1.
For convenience of readily and equally adjusting both ends of the shaft, the
heads of the screws may be graduated:
ر

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Mowat in the, Great Seal Patent Office on the 12th
June 1883:
"
JOHN MOWAT, of Barrhead, in the County of Renfrew, North Britain,
"IMPROVEMENTS IN PENTAGRAPH ENGRAVING MACHINES,"
My said Invention, which relates to improvements 'in pentagraph engraving
machines, has special reference to novel means or appliances for varying the extent
of motion of the roller or cylinder being. engraved, to compensate for irregularities
in the diameter of different rollers or cylinders employed.
It is essential in engraving the copper or steel cylinders used in calico printing
and for similar purposes, that the "repeat" of the pattern engraved should fit
within the circumference of the cylinder, and in the class of pentagraph engraving
machines in which the engraving diamonds only traverse in one direction.while the
formation of the pattern is completed by the rocking motion or partial rotation of
the cylinder it has been hitherto only possible to adjust the levers of the pentagraph
to a slight extent for this purpose, and that without securing precision in fitting in
the pattern to suit different diameters of cylinders. The present improvements
which are designed to overcome this difficulty, consist in forming the supporting
and actuating discs, which carry and rock or partially rotate the cylinder, or roller
being engraved with beveled edges, or in the form of frustra of cones or of stepped
cones decreasing in diameter at their inner faces, so that the position of the cylinder
or roller on the discs may be adjusted towards or from the centre of the, discs, and
consequently the extent of motion of rotation of the cylinder in relation to that of
the discs may be varied.
34
:
Fri 1
The Invention is illustrated by the accompanying Drawings, in which figure 1 is
a transverse vertical section, and figure 2 is a longitudinal vertical, section of a
pentagraph engraving machine to which my improvements are applied. Figure 3
is an elevation of part of the framing of the machine showing the mode I adopt of
supporting the weight of the copper cylinder. Figure 4 is a sectional elevation of
the rocking shaft, fitted with a modified arrangement of the discs which support
and give motion to the cylinder to be engraved. Figures, 5 and 6,are end eleva-
tions of these discs.. Figures 7 and 8 are end and side elevations of a modified
form of disc, and figure 9 is an elevation showing a further modification of the
Invention.
The machine illustrated is of the ordinary "cradle" class, having side frames
A, A, supporting a concave table or cradle B over which is mounted the rocking
shaft C carrying the discs D which give motion to the copper, cylinder,E which is
to be engraved. On the rocking shaft Care fitted the usual swinging arms C' with
the steel band and pulleys through which the motion of the style cover a pattern,
or design fitted in the cradle, is transmitted on a reduced scale to the cylinder E,
and to the carriage fitted with the usual rows of diamonds which engrave.the
cylinder. Instead of being carried on and turned by contact with the peripheries
of the usual round discs, the ends of the roller E bear on discs D having beveled
edges. For this purpose, the cylinder E may be turned at the ends to fit the
beveled edges of the carrying discs D, which may be roughened or serrated, and the
liscs D are fitted to slide on their carrying shaft C, so that they can be adjusted at
greater or less distance from each other. This lateral adjustment which admits
of the copper cylinder being supported on the beveled faces of the discs at a greater
r less distance from the centre of the disc shaft, may be effected in different ways..
In the arrangement shown in the Drawings, the boss D¹ of each disc D is provided"

page_text: with a pinching screw d to secure it to the shaft C, and a sleeve D is fitted and
secured on the shaft C outside the boss D¹, and is fitted with a screw nut D³, which
may be screwed out or in on the sleeve D2 to bear on the end of the boss D¹, and
prevent any further lateral motion after the discs are set in the desired position.
In order to facilitate the setting of both ends of the copper cylinder E at the
same relative positions upon the beveled edges of the carrying discs D, and also to
prevent any undue abrasion of the turned ends of the cylinder E, an adjustable
segment F is fitted to the inner side of each disc D and may be brought round to bear
on the cylindrical surface of the cylinder E, at the time the cylinder is being set in
position. The segmental piece F is fitted to slide on a block F¹ fitted on the boss
of the disc D, and the adjustment of the segment F, to suit different diameters and
positions of the cylinder, is effected by means of a screw of connecting the sliding
segment and block.
The ends of the shaft or mandrel E¹, on which the cylinder or roller E is mounted,
are carried in the usual bush bearings, and the bushes e are fitted to slide vertically.
The adjustment of these bushes e, or of the shaft E' to correspond with the adjustment
of the position of the cylinder E, is effected by means of screws e¹ passed through
the bearing brackets e² and bearing on the under side of the bushes, or of the shaft.
For convenience of readily and equally adjusting both ends of the shaft, the
heads of the screws e¹ and the fitting segment F may be graduated.
In the modified arrangement of the discs D shown in figures 4, 5, and 6, a
segmental plate D presenting a truly cylindrical bearing for carrying the roller E,
is fitted on the side of the beveled disc D.
This plate D is so fitted on the boss of the disc D, that it can be turned down.
out of the way of the roller E as indicated, and is only used when rollers of a mean
diameter are to be engraved. When the plate D is moved round to allow the
roller E to rest on it at each end there is inserted a stop pin d' which is provided to
secure the plate D4 both in the working position and when lowered out of the way.
In this arrangement the beveled edges of the discs D are used if the cylinder to
be engraved is not of such a size as to admit of the segmental plate D* being
employed.
In the arrangement shown in figures 7 and 8, a part of the periphery of each
disc D is beveled, and the central part D³ is made of true cylindrical form for use
when engraving rollers of mean diameter. As only a portion of the periphery of
each disc is required in practice, the beveled part is not continued entirely round
the disc, but the lower part D5 is stepped.
In the modification shown in figure 9, the roller E does not bear directly on the
discs D, but the carrying mandrel E¹ has fitted on each end a beveled disc or
plate E which bears on the disc D, and through which the motion of the discs D is
communicated to the roller E. The discs E' are fitted to slide on the mandrel E¹,
so that they may be moved out of the way when the beveled part is not to be
used, and the ends of the roller E may then be allowed to bear upon either of a
series of steps D³ formed on the discs D, or the flat portion of the discs E² may bear
on the stepped part D of the discs D. An adjustable style or pointer H may be
fitted to each disc E2, and be used to facilitate the fitting in succession of a number
of 'rollers of the same diameter, a number of marks h' being formed on the discs D,
against one of which the-style or pointer could be brought, and again set when
fitting a new roller.
Having now described my said Invention, and the manner in which the 'same is
to be performed, I declare that what I claim as my Invention is:-
First. The arrangement and combination with the rocking shaft (C) in a penta-
graph engraving machine, of the beveled or stepped discs supporting the ends of
the cylinder or roller to be engraved, substantially as herein described and
illustrated, and for the purpose set forth.
Second. In a pentagraph machine the discs D fitted adjustably on the rock
shaft C, and formed with beveled or stepped peripheries by which the copper

page_text: cylinder or roller is actuated, substantially as herein described and illustrated, and
for the purpose set forth.
Third. Forming the carrying discs (D) of pentagraph engraving machines with
beveled or stepped or combined beveled and stepped peripheries, substantially as
and for the purpose herein set forth.
In Witness Whereof, I the said John Mowat, have hereunto set my
hand and seal this Eighth day of June, in the year of our Lord One
thousand eight hundred and eighty three.
0 Witness
WALLACE FAIRWEATHER, C.E., Fel. Inst. P.A.
Of W. R. M. Thomson & Co
+
Patent Agents
Glasgow.
JOHN MOWAT (L.S.).