Improvements in Duplicating Apparatus.
Year: 1899

page_text: Date of Application, 12th Sept., 1899-Accepted, 16th Dec., 1899
COMPLETE SPECIFICATION.
Improvements in Duplicating Apparatus.
I, BENJAMIN JOSEPH BARNARD MILLS, of 23, Southampton Buildings, in the
County of London, Patent Agent, do hereby declare the nature of this invention
(a communication to me from the A. B. Dick Company, of 154, Lake Street,
Chicago, Illinois, in the United States of America, Manufacturers), and in what
manner the same is to be performed to be particularly described and ascertained
in and by the following statement :-
--
The present invention relates more particularly to duplicating apparatus such
as the mimeograph, in which is employed a stencil sheet of waxed paper, the
ink being forced through the perforations therein in such manner as to be
deposited on the sheet below. The object of the invention is to simplify the
construction of duplicating apparatus and increase its efficiency, chiefly with
respect to the means for mounting the diaphragm or top sheet through which
the ink is passed to the stencil and maintaining such top sheet in position, and
with respect to the means for securing the stencil in position below such top
sheet.
To these ends the invention consists in the construction and arrangement of
the several parts as illustrated in the drawings, in which Figure 1 is a perspective
view illustrating the under side of the hinged member of a duplicating apparatus,
and Figures 2, 3 and 4 are detail sectional views taken on the lines 2-2, 3-3,
and 4-4, respectively, of Figure 1.
Referring to these figures, in which similar letters of reference denote corre
sponding parts, A designates the hinged leaf consisting of a frame having side
pieces a, a, and end pieces a¹, a¹. At one end this frame is provided with lugs ²,
forming part of the hinge by means of which said frame is secured upon the bed
member of the apparatus. The latter being of the construction now widely
known and in use is not here illustrated. As will be readily understood, in
duplicating apparatus of the type under discussion, the bed upon which the
paper to be printed on is placed is, in operation, stationary, while the hinged
member carrying the stencil and the diaphragm is raised upon its hinge in order
to remove the printed sheet and to substitute therefor a sheet, to be printed
upon.
B designates the diaphragm, formed preferably of woven fabric of such structure
as to permit the ink to be readily passed therethrough to the stencil below. This
diaphragm is preferably provided with a margin b, formed by varnishing or
waxing, in order that the area through which the ink may pass shall be limited
to the size of the writing upon the stencil sheet. Said diaphragm is mounted
in a detachable frame, consisting of side pieces C and end pieces C. To this
frame it is secured by any suitable means, and the whole frame, carrying the
diaphragm, is secured to the hinged leaf A in such manner as to permit its
ready removal when desired. In the present instance, the means for securing
the diaphragm frame in position is shown as consisting of clamping cams D
pivoted at d upon the side members a of the frame A. In Figures 1 and 3, these

page_text: are shown in such position as to firmly secure the diaphragm frame to the
frame A. In order to release the former, it is only necessary to swing the
cams I to the left by means of the outwardly extending and downwardly pro-
jecting ends thereof.
The utility of the detachable diaphragm frame will be appreciated when it
is understood that it is of importance to have the diaphragm supported in such
manner that it will not wrinkle. In order to so arrange said diaphragm, it is
desirable to remove the supporting means entirely from the machine, in order
that it may be laid flat and the diaphragm applied and secured with care, so as
to obtain the best results.
Turning now to another feature of the present invention, heretofore alluded to,
this concerns the means for securing the stencil sheet in position. In apparatus
formerly employed, it was common to secure the stencil sheet not only at the
top and bottom but also at the sides. In later apparatus, provision was made
for securing the stencil sheet only at the top and bottom, but for various
reasons, such, for instance, as variations in the thickness of the stencil sheet,
this arrangement has proved defective. In the construction illustrated in the
drawings, the efficiency of the means for securing the stencil sheet is unaffected
by variations in the thickness of said sheet, said means operating to hold the
sheet firmly at top and bottom under all conditions, and being capable of ready
and easy operation.
The means for securing the stencil sheet to the hinged leaf or frame A and
under the top sheet B consists of mechanism which is duplicated at each end
of said frame. That at but one end need, therefore, be described in detail. Such
mechanism consists, first, of the clamping bar E, hinged at e to the end member a¹
of the frame A. As here shown, this clamping bar extends nearly from end
to end of the end member and practically forms part of the frame A. The
under side of the clamping bar E is provided with a longitudinal groove el, which
coacts with a spring-actuated rod F, the ends of which may, if desired, be
decreased in diameter as shown at f. f¹ designates coiled springs, here shown
as located in recesses f in the end members a¹ of the frame A. These springs fl
exert their pressure against said rod F, tending to force it into intimate relation
with the groove e in the clamping bar E.
The clamping bar E is secured in closed position by means of the locks G
hinged upon the upper surface of the frame A. Those portions of the locks G
which perform the locking operation are substantially U-shaped, as shown most
clearly in dotted lines in Figure 1, so that when in operative position said clamps
shall practically embrace the end of the frame A, holding the clamping bar E
firmly in the position in which it appears in full lines in the drawing. The
locks G are also preferably provided with finger-pieces g¹ for ease of operation.
In securing the stencil sheet in position, it is only necessary to release the
locks G and raise the hinged clamping bar E, whereupon the end of such sheet
may be laid over the spring-actuated rod F, the locking bar brought down upon
it and secured in position by means of the locks G. By reason of the movement
of the rod F, permitted by the coiled springs fl, very considerable variation in
the thickness of the stencil sheet is permitted. After one end of the stencil
sheet has been locked as described, said sheet may be drawn taut and its other
end secured to the other clamping device in the same manner, whereupon the
stencil sheet will be arranged, without buckling or wrinkling, smoothly below
the diaphragm, the whole operation being exceedingly simple and requiring but
a moment.
If desired, the end members a¹ of the frame A may be provided with a groove
immediately beneath the rod F, in order to give said "bar greater scope of vertical
movement. In the present instance, are shown clips H secured at or near the
ends of the side members of the frame A and extending around such side
members to the under side thereof, where their ends are located over the ends

page_text: of the rod F so as to preclude disarrangement of said rod due to the pressure of
the coiled springs fl. It is obvious, of course, that these clips may be readily
dispensed with, small. plates or pins secured to the under side of the members a
of the frame being substituted to meet the same requirement.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is:―
1. In a duplicating apparatus, the combination with the bed and stencil-carry-
ing members, of a detachable frame and a diaphragm supported thereby, sub-
stantially as set forth.
2. In a duplicating apparatus, the combination with the bed and stencil-carry-
ing members, of a detachable frame, a diaphragm supported by said frame, and
means for locking said frame in position, substantially as set forth.
3. In a duplicating apparatus, the combination with the bed and stencil-carry-
ing members, of a detachable frame, a diaphragm supported thereby and locking
devices carried by said stencil-carrying member and adapted to lock said dia-
phragm frame in position, substantially as set forth.
4. In a duplicating apparatus, the combination with the bed and stencil-carry-
ing members, of a detachable frame supporting a diaphragm and a stencil
arranged in proximity to said diaphragm, and secured to said stencil-carrying
member by its ends only, substantially as set forth.
5. In a duplicating apparatus, the combination with the bed and stencil-carry-
ing members, of a stencil and means for securing the same at each end including
clamping devices and locking mechanism coacting therewith, substantially as
set forth.
6. In a duplicating apparatus, the combination with the bed and stencil-carry-
ing members, of a stencil and means for securing the same at each end including
hinged clamping devices adapted to secure stencils of varying thickness and
locking mechanism for said devices, substantially as set forth.
7. In a duplicating apparatus, the combination with the bed and stencil-carry-
ing members, of a stencil and means for securing the same at each end including
hinged clamping devices coacting with spring-pressed surfaces and locking
mechanism for said clamping devices, substantially as set forth.
8. In a duplicating apparatus, the combination with the bed and stencil-carry-
ing members, of a stencil and means for securing the same at each end including
hinged clamping bars coacting with spring-pressed rods, the ends of said stencil
being placed between said bars and rods, and locking devices for securing said
bars in position, substantially as set forth.
9. In a duplicating apparatus, the combination with the bed and stencil-carry-
ing members, of a stencil and means for securing the same at each end including
hinged clamping bars provided with grooves and coacting with spring-pressed
rods, the ends of said stencil being placed between said bars and rods, and locking
devices for securing said bars in position, substantially as set forth.
Dated this 19th day of Sentember 1899
HARRIS & MILLS,
23, Southampton Buildings, London, W.C., Agents.