An Improved Method of Casting Electric Accumulator Plates and Apparatus therefor.
Year: 1898

page_text: Date of Application, 4th May, 1898-Accepted, 17th Dec.,
1898
COMPLETE SPECIFICATION.
An Improved Method of Casting Electric Accumulator Plates and
Apparatus therefor.
We, JOSEF HESSE, of 9, Gebhardstrasse, Fürth, Bavaria, in the Empire of
Germany, Manufacturer, and JOSEF KERNAUL, of 14, Zenettistrasse, Munich,
in the Empire of Germany, Manager, 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:
―
As is well known, lead plates with projections made thereon which form between
them grooves or furrows tapering outwardly are particularly advantageous as
holders for the paste or active mass in electric accumulator batteries. The casting,
of these ridged plates has however hitherto developed difficulties, as on account
of the under cut form of the ridges the moulds could not be removed from the
cast plates without further trouble and it was therefore only possible to cast same
with the assistance of complicated moulding machines in which a mutual adjust-
ment of the separate parts of the mould had to be effected in order to allow of
the cast plate being separated from the mould.
According to the present invention this difficulty is solved in the simplest manner
by casting the ridge plates in the form of an are preferably in the form of a circle
instead of casting them directly with the desired tapering grooves, and then, after
casting, bending them into a straight shape. In this operation, there may be
formed on the arched or curved plates ridges which are narrower at the base than
at the point, that is to say which are undercut without the grooves or interstices
between the ridges narrowing outwardly so that thus a separation of the cast
plate from the mould affords no difficulties. If the curved ridge plate thus
obtained be bent into a straight form the ridges come closer together at the point
and the interstices between them thereby become narrower towards the outside
and the desired grooves or recesses tapering to the outside are obtained.
In the accompanying drawings there is shown a suitable mould for carrying out
the above mentioned method, Figure 1 being a vertical section and Figure 2 a
horizontal section of the same: Figure 3 is a part of the horizontal section
Figure 2 on an enlarged scale: Figure 4 shows the grooves tapering to the outside:
Figure 5 shows teeth formed in the plate.
Å suitable number of vertical bars c and d are arranged on a bed plate a
around a vertical cylindrical core b thereon, in such a way that between the bars
and the core there remains the desired profile of the plate to be cast. For this
object there are employed preferably alternately broad bars e provided with a
suitable ridge el, and narrow bars which are so calculated that in their correct
position they lie closely one against the other. These bars and may either
be employed all around alone, or if the plate to be cast is not to be so large as the.
circumference of the core amounts to, then in order to assist the bars and d
to form a complete ring special broad filling bars e may also be employed. The

page_text: bars c, d and e all taper upwards and are firmly held together in the form of a
ring or arch by means of rings f which are placed over them and driven down-
wards on the same. The number, position and height of the rings f is optional.
As may be seen in Figure 3, the ridges or ribs c¹ of the bars c as well as the
inner ends of the bars d have lateral faces which do not extend radially but which
are parallel to one another, so that in the plate to be cast the ridges to be formed
thereon have outwardly a suitably greater width than on the inside that is to say
the ridges or ribs are undercut whilst the recesses or grooves between the ribs
have externally and internally the same width or breadth. Consequently when
the casting is completed and the ring f removed, the bars c and d may be easily
removed from the cast ridge bars and taken away. The curved ridge plate obtained
is then straightened by means of a suitable apparatus by which means the outer
side of the plate which in its curved form is larger than the inner is rendered
equal to the inner, consequently the ribs are approached together at the points
and thereby the desired even rib plate with grooves narrowing to the outside
(Figure 4) is obtained.
If these rib plates are to be provided on their rear side with longitudinal ribs
with the object of strengthening them, it is only necessary in order to attain this
end to provide the core 6 with suitable recessed or counter-sunk annular grooves
which during the casting also become filled with the molten material and produce
the desired longitudinal ribs on the plate.
If the bars d and c be provided on their inner side with teeth or studs as shown
in Figure 5 tapering towards their points, either rounded or angular, there results,
in the cast plate, suitable grooves notches or recesses which taper towards the
back side, that is to say in the opposite direction to the under cut ribs which
are cut from the front side. These are under cut from the rear side outwardly.
In this manner lattice rib plates or grids may be obtained with interstices tapering
or under cut towards both sides which plates are therefore very advantageous
for coating on both sides with the paste or active mass.
Figure 6 is a vertical Figure 7 a horizontal section and Figure 8 a plan of such
a lattice rib plate obtained by the form of the bars c & d provided with grooves i
narrowing to the front side and with openings tapering to the back side of
the plate.
Of course it is no departure from the principle of the present invention if the
plates be so made that the grooves, recesses or interstices when the plate has been
straightened do not taper to the outside but remain of equal width at the outside
and the inside or even widen towards the outside from the inside, as the process
or method hereinbefore described is advantageous for such plates also because it
allows of a particularly easy removal of the moulding parts from the cast plate.
It is desired to protect in general the casting of ridged plates or grids in a bent
form and the subsequent bending straight of the same.
Having now particularly described and ascertained. the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is:-
1. A method of making electric accumulator ridged plates or grids characterized
by the plates being cast in a circular or other bent form and then bent back into
a straight form with the object of enabling the moulding parts to be removed
directly and easily from the bent cast plate in which the grooves widen to the
outside and thus render possible the casting of under cut ridges or ribs which,
when the plate is bent straight, yield grooves recesses or interstices tapering to
the outside, substantially as hereinbefore set forth.
2. For carrying out the hereinbefore described method of making electric
accumulator plates or grids, a mould consisting of a round core (b) and separate
bars (cde) tapering, upwards in a wedge form and arranged round the core. in
an annular form adjacent to one another, which bars are adapted to be held
together by one or more rings (f) in such a way that after the removal of said

page_text: rings they may be taken off separately from the cast plate, substantially as
described.
3. A form of construction of the-mould hereinbefore described for casting electric
accumulator plates or grids, in which the bars (c and d) are provided with teeth
or studs tapering towards the point with the object of making perforated, i.e.
lattice rib plates or grids with grooves tapering to both sides, substantially as
described.
1 1
1000
W. P. THOMPSON & Co.,
Of 6, Lord Street, Liverpool, Agents for the Applicants.