Improvements in or relating to Bending Flat Electrotype Plates to a True Circular Form and in Apparatus therefor.
Year: 1890

page_text: Date of Application, 26th Aug., 1890-Accepted, 4th Oct., 1890
COMPLETE SPECIFICATION.
Improvements in or relating to Bending Flat Electrotype Plates to
a True Circular Form and in Apparatus therefor.
A communication from abroad by THE CURVED ELECTRO-TYPE COMPANY, of Albany,
State of New York, United States of America.
I, WILLIAM PHILLIPS THOMPSON F.C.S., M.I.M.E., of the Agency for Foreign
Patent Solicitors, 6, Lord Street, Liverpool and 6, Bank Street, Manchester, both in
the County of Lancaster and 323 High Holborn, in the County of Middlesex,
Civil Engineer, 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 aim of the invention is to effect the bending of flat electrotype plates to a true
circular form without fracturing or mutilating their print surfaces, and this to the
end that they may be used on cylinder presses for the production of print of the
highest quality.
To this end the electrotype is sustained on its outer or printing surface by a flat
highly tempered plate of steel or like material, of such thickness and strength that it
serves as a firm support and strongly resists a bending action, and while thus sustained
a bending pressure is applied to its back by a cylinder, curved die or equivalent
means, and at the same time a gradual bending of the steel plate is effected whereby
it is caused to bend the electrotype gradually uniformly and positively until it acquires
the
proper form.
The essence of the invention resides in the method of bending an electrotype by
bending a strongly resisting resilient plate against its printing surface while a bonding
pressure is applied from the opposite side, and the mechanism to this end may be
constructed and arranged in a variety of forms. The accompanying drawings show
several mechanisms adapted for the purpose, in which,
Figure 1 is a perspective view of the preferred mechanism forming a part of the
present invention.
Figure 2 is a cross-section on the line X-X of Figure 1.
Figure 3 is a perspective view of the mechanism shown in Figure 1.
Figure 4 is a perspective view of another form of apparatus containing the elastic
plate as a fundamental feature.
Figure 5 is an outline elevation showing another mechanism for the same purpose.
Referring to Figures 1 and 2:
A represents a flat bed or table which may be constructed and sustained in any
suitable manner, and B a heavy cylinder or roll mounted upon the table and adapted.
to roll thereover. The table is provided along its opposite sides with the two toothed
bars or racks a, and the ends of the cylinder provided with corresponding teeth b, to
engage the same, and this for the purpose of compelling the two ends of the cylinder
to traverse the table at the same speed and to enable the cylinder to apply longitudinal
tension to the resilient plate as herein described.
C represents a plate of highly tempered steel or equivalent material which will
resist a bending action and assume a flat or substantially flat form when released.
This plate is to be of such thickness and strength that it will strongly resist any effort
made to bend it and be self sustaining in order that it may serve, when bent, as a
strong curved support for the electrotype. As regards its strength and stiffness the
plate is to be clearly distinguished from the blankets and thin metal sheets used in other
bending machines between the type surface and the bending devices proper as a
means of protecting the type from mutilation. It is held upon the surface of the
table and fixed thereto at one end by clips c, or equivalent fastening devices, while the
opposite end is attached by clips c or other suitable fastenings to the surface of

page_text: the cylinder, the arrangement being such that when the cylinder is at one end of the
table the plate is extended in flat form, but on rolling the cylinder lengthwise of the
table the sheet is wound closely around it under longitudinal tension in the manner
represented in the drawing.
D represents the electrotype to be bent. It is laid face down upon the flat plate C,
with one end inserted between the plate and overlying cylinder. A sheet of mill-
board, cardboard, or equivalent material E is commonly introduced between the
electrotype and the plate for the purpose of protecting the printing surface, but
this is not in all cases a necessary feature.
As the cylinder is rolled forward the electrotype is bent upward with a progressive
action from one end to the other and wound tightly into the space between the surface
of the cylinder and the face of the flexible plate so that the back of the electrotype
is caused to conform exactly to the surface of the cylinder, while its outer or printing
face is given a true cylindrical form without in the slightest degree impairing the
sharpness of the lines or characters thereon.
In practice it is found that electrotypes for printing high-class engravings, maps,
and the most delicate type may be bent by this system in such manner that when used
on a cylinder press they will give results fully equal to those ordinarily attained by
the use of flat plates.
In order to relieve the electrotype from undue strain and pressure bearers may be
- provided to maintain a suitable distance between the cylinder and the elastic plate.
In Figures 1 and 2 these bearers are in the form of annular collars or bands d,
encircling the cylinder and adapted to act upon the surface of the plate C, outside of
or beyond the edges of the electrotype. It is to be distinctly understood that the
invention is not restricted to the use of the bearers.
Referring now to Figure 3 the apparatus therein represented consists of a bed or
table A, a cylinder B, and a resilient plate or sheet C, as in the first named example.
The plate will be attached at one end to the roll and may be and preferably is attached
at the opposite end to the table. The bearers d, instead of being attached to the
cylinder, are applied to the bed or table along the edges of the resilient plate so as to
wind upon the cylinder and maintain a suitable separation in order to relieve the
electrotype from excessive pressure. It will be perceived that when the bearers are
used in either form that portion of the plate which has acquired the true curvature is
substantially relieved from strain and pressure.
While it is preferred to employ a complete cylinder or roll, it will, of course, be
understood that a segment of a cylinder may be used provided it has sufficient surface
to receive the electrotype, and it is also obvious that the cylinder or roll may be
operated either by hand or by mechanism of any appropriate form.
In the form of apparatus represented in Figure 4, A represents the bed or table
having a concave cylindrical surface and B the bending die formed of a segment of a
cylinder sustained and operated by a screw F in a sustaining arm or bracket G ; C is
the flat resilient plate resting upon the bed-plate and bearing on its upper surface the
electrotype D. When the die is lowered it applies a bending pressure to the back of
the electrotype, which in turn carries downward the central portion of the plate C.
The bending action commencing at the middle is carried outward in both directions
toward the edges of the plate, and the electrotype and the underlying plate are
brought gradually to the required cylindrical form.
When the die is carried to its lowest point so as to confine the plate and the electro-
type between it and the bed, the operation is complete.
In Figure 5, H H H represent three parallel rolls arranged in such relation that
they will give a cylindrical curvature to a plate passed between them after the manner
of the rolls commonly used for the bending of boiler plates and for like purposes.
Crepresents the resilient plate on which the electrotype D is sustained. It is found
that by passing the plate and the electrotype thereon between the rolls a bending
action is secured far superior to that obtained when the resilient plate is omitted.
It is to be observed that in each form of the apparatus herein shown the flexible or
resilient plate is an essential feature. With the exception of the plate no claim is

page_text: laid to either form of apparatus herein shown except that represented in Figures 1, 2
and 3.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed as communicated to me by
my foreign correspondents, I declare that what I claim is :---
1. The method of bending an electro-type plate consisting in subjecting its back to
the pressure of a continuous curved surface, and at the same time bending against its
face a strong flat resilient plate.
2. The method of bending an electro-type plate consisting in supporting the same
at the back by a rigid curved surface and at the same time bending against its
face with a progressive action a strongly resisting longitudinally strained resilient
plate.
3. In a machine for bending electro-type plates the combination of a normally flat
resilient plate adapted to strongly resist a bending action, means for applying a
bending pressure to the back of the electro-type, and means for bending the plate
against the face of the electro-type.
4. The combination, substantially as shown of the bed or table, the roll or cylinder
movable thereover, and the intermediate resilient plate attached at one end to the bed
and at the other to the roll.
5. The combination, substantially as shown, of the bed or table having teeth, the
rell movable thereover and provided with corresponding teeth and the intermediate
flexible plate attached at its ends to the roll and the table respectively.
6. In a machine for bending electro-type plates, the combination of a roll or
pressure device having a cylindrical surface to act on the back of the electro-type, a
flexible plate, and means for winding the same upon the roll, and intermediate bearers,
maintaining suitable separation of the roll and plate.
Dated this 25th day of August 1800
WM. P. THOMPSON & Co.,
Agents for the Applicant.