Improved Devices for Mounting and Locking Interchangeable Stereotype and Electrotype Plates on or to their Bases.
Year: 1891

page_text: Date of Application, 13th Aug., 1891-Accepted, 19th Sept., 1891
COMPLETE SPECIFICATION.
Improved Devices for Mounting and Locking
Interchangeable
Stereotype and Electrotype Plates on or to their Bases.
I, DAVID REID of Caxton Buildings Little Collins Street in the City of
Melbourne and Colony of Victoria Publisher 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:-
This invention has been devised for the purpose of providing better means for
mounting and locking interchangeable stereotype and electrotype plates on or to
their bases than those already known.
Those which I have invented enable the plates to be mounted with greater ease
and facility and when mounted are more securely fixed in position than by other
means and furthermore such plates are automatically justified when being locked
up in the forme.
It is well known that keys of various shapes and especially double dovetailed
keys have been used for the purpose of fitting into corresponding grooves in the
underside of the plate and the upper face of the base but hitherto such keys and
such grooves have been made in one direction only and generally from one end of
the base and plate to the other. Now my invention consists in connecting such
plates to their bases by means of keys which have a double dovetailed groove all
around them and by making single dovetailed grooves at or about right angles to
each other in the underside of the plate and the upper face of the base respectively,
such grooves being made of the exact size to receive the double dovetailed keys
which I have just described. It will thus be noticed that where there is a dove-
tailed groove in the plate there is no corresponding groove in the base and so with
the dovetailed grooves in the base also, but these grooves are so made as to
intersect each other when the plate is slid into its position on the base.
I prefer to make these grooves running longitudinally from each end of the
underside of the plate and crosswise from each side of the base near each end when
two only are used. So long however as they intersect each other and so long as
the key is made of such a shape as to correspond with the grooves at their inter-
section the precise position of such grooves may be altered or varied at will. In
some cases as for instance when the plate is wide enough for two or more columns
of type I increase the number of grooves so as to admit of more than two keys
being used for each plate. In the case of a plate which is wide enough to cover
say four columns, I should prefer to make four longitudinal grooves at each end of
the plate and two cross grooves at each side of the base so as to admit of eight
keys being used for the one plate. It is obvious that by lengthening the grooves
in the plate or running them from end to end three or more cross grooves could
then be cut in the base so as to give a greater number of points of intersection thus
giving the opportunity of using a greater number of keys should such be found
necessary for very large plates. I have found in practice however that four keys,
two at each end are sufficient to hold any ordinary plate. It is to be noted that the
longitudinal grooves proceeding from one end of the plate must be made as nearly
as possible twice as long as those proceeding from the other end of the plate so as
to admit of the plate being slid longitudinally over the first key or set of keys in a
wide plate with which the base is fitted sufficiently far to leave the other cross
groove at the other end of the base free to receive the other key or keys. The
bases may be made in sections and pieced together if so preferred so as to fit all
variations of shape and size of plates.

page_text: -
Furthermore the shape of these keys may also be varied by making them round
polygonal or diamond shaped so long as they are susceptible of engaging in each of
the grooves hereinbefore referred to..
Referring to my drawings:
Figure 1 shews a plan of the upper face of a base having dovetailed grooves A.
made crosswise in its face, whilst,
Figure 2 shews plan of the underface of the plate having longitudinal dovetailed
grooves B.
Figure 3 shews plan of the plate and base combined, the respective grooves in
the plate and base being shewn in dotted lines.
Figure 4 shews longitudinal section on the line 4, 4 Figure 3, whilst,
Figure 5 shews longitudinal section on line 5, 5, Figure 3.
Figure 6 shews side view, and
Figure 7 end view of the plate and base combined.
Figures 8, 9 and 10 shew respectively, plan, elevation and section of the double
dovetailed key.
Figures 11, 12 and 13 shew respectively plans of keys of a different shape, the
first two of which may be used as substitutes for that shewn in Figure 8, whilst
Figure 13 shews plan of a key which is suited for use in the event of the grooves
being made as shewn in Figure 14 in which it will be seen the grooves are some-
what differently arranged, there being only one continuous longitudinal groove in
the underside of the plate instead of two as shewn in Figures 2 and 3. This is
necessitated by the different arrangement of the cross grooves on the upper surface
of the base.
Figure 15 is a longitudinal section on line 15 in Figure 14.
Figure 16 shews plan of a plate and base in which there is a still further
variation in the arrangement of grooves and in the shape of the key.
Figure 17 is a section on line 17, 17 in Figure 16.
From these drawings it will be seen that the double dovetail in the key is
produced by simply making the edges V-shaped.
Figure 18 represents a plate which has been fitted over one key which has been
slid first into the cross groove A' in the base and, secondly into the longitudinal
groove B in the plate, this latter has then been pushed down into the position
shewn so as to allow the second key being slid into the other cross groove A² until
it comes into line with the longitudinal groove in the plate, when the latter is slid
over it and the plate can then be adjusted either laterally or lengthwise with the
greatest ease.
When about to connect a plate with a base according to my invention I first
slide one or more of the keys into the cross grooves at one end of the base and then
slide the long groove or grooves in the plate over the key and push it sufficiently
far to admit of the second key or set of keys being slid into the cross groove or
grooves in the other end of the base when I slide the other end of the plate over
said key and when this has been done the plate can be adjusted laterally or longi-
tudinally to any extent that may be required within the limit prescribed by the
grooves, which are made sufficiently long to admit of any adjustment which is
likely to be required in actual practice.
It will readily be seen that any keys which will admit of engagement with both
sets of grooves will answer the purpose but I prefer to make bases, plates and keys
as shewn in Figures 1. 2 and 3. The bases must of course be made of such a
thickness as that when the plates are locked to them they will be exactly type
high.
The bases may be made of any suitable metal and the keys of any material
which will answer the purpose although I prefer these latter to be made of
brass.
Plates that are mounted according to this invention can be readily slid off their
bases and be replaced by others without disturbing their bases or the surrounding
type or plates which is a matter of very great convenience to the printer.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed 1 declare that what 1
claim is:
My improved devices for mounting and locking interchangeable stereotype and
electrotype plates on or to their bases such devices consisting essentially of single
dovetailed grooves made in the underside of the plate and the upper face of the
base in such a manner as that said grooves will intersect each other when the
plate is placed in position upon the base in combination with double dovetailed
keys which will fit and engage with both of said grooves at their intersections
substantially as herein described and explained and as illustrated in my drawings.
Dated this Sixth day of July One thousand eight hundred and ninety-one.
DAVID REID.