An Improvement in Plates for Secondary Voltaic Batteries.
Year: 1888

page_text: An Improvement in Plates for Secondary Voltaic Batteries.
We, BERNARD. MERVYN DRAKE and JOHN MARSHALL GORHAM both of No. 2
Princes Mansions, Victoria Street, Westminster in the County of Middlesex,
Electrical Engineers do hereby declare the nature of this invention to be as
follows:-
Plates to hold oxide for secondary voltaic batteries are usually made as grids
presenting a number of cells for holding the oxide. These cells being usually made
wider at their mouths on each side of the plate than they are in the middle, the plugs
of oxide are apt to break across their middle, so that one half or both halves drop out.
Our invention relates to means of preventing this, which we effect in the following
manner. We cast the grids with ribs having cross section of the usual diamond form
but deeper than usual, so that the edges of the ribs project beyond the plane that is to
form the finished surface of the plate. We then burr over or burnish down the pro-
jecting edges of the ribs, displacing the metal so that each rib presents a lip projecting
towards the cell on each side of it. These lips serve to hold in the oxide with which
the cells are charged. As a convenient way of effecting the burring over, we pass the
ribs of the grid under a blunted revolving or planing tool which pressing on the
projecting edges of the ribs displaces and squeezes down the soft metal, causing it to
project as a lip on each side of each rib without cutting any off. Or, instead of
employing the pressure of a blunt tool as above described, the edges of the ribs may
be burred over by repeated blows of a light hammer or percussion tool.
Dated this 14th day of March 1888.
ABEL & IMRAY,
Agents for the Applicants.

page_text: COMPLETE SPECIFICATION.
An Improvement in Plates for Secondary Voltaic Batteries.
We, BERNARD MERVYN DRAKE, and JOHN MARSHALL GORHAM, both of No. 2
Princes Mansions, Victoria Street, Westminster, in the County of Middlesex,
Electrical Engineers, 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 :-
Plates to hold oxide for secondary voltaic batteries aro usually mado as grids
presenting a number of cells for holding the oxide. These cells being usually made
wider at their mouths on each side of the plate than they are in the middle the plugs
of oxide are apt to break across their middle so that one half or both halves
drop out.
manner.
Our invention relates to means of preventing this which we effect in the following
We cast the grids with ribs having cross section of the usual diamond
form, but deeper than usual, so that the edges of the ribs project beyond the plane that
is to form the finished surface of the plate.
We then burr over or burnish down the projecting edges of the ribs, displacing the
metal so that each rib presents a lip projecting towards the cell on each side of it.
These lips serve to hold in the oxide with which the cells are charged.
As a convenient way of effecting the burring over we pass the ribs of the grid
under a blunted revolving or planing tool which pressing on the projecting edges of
the ribs displaces and squeezes down the soft metal causing it to project as a lip on
each side of each rib without cutting any off. Or, instead of employing the pressure
of a blunt tool as above described, the edges of the ribs may be burred over by repeated
blows of a light hammer or percussion tool.
Fig. 1 of the accompanying drawings is a section and Fig. 2 is a plan of part of a
grid to constitute a battery plate as it is cast with the ribs made of the usual
diamond section to give facility in casting, but deeper than the sides s of the
plate.
Fig. 3 is a section and Fig. 4 is a plan of the grid after the tops of the ribs have
been flattened down to the level of the sides s, the displaced metal forming a burr on
each side of each rib, so that each of the cells between the ribs has inwardly projecting
lips on both sides. Fig. 5 is an elevation of a revolving tool suitable for effecting the
burring over of the ribs of the plate which is made to slide under it. Fig. 6 is a side
view of part of the tool first used to burr over the ribs in the one direction. Fig. 7
is a front view of the same. Figs. 8 and 9 are corresponding views of the tool under
which the plate is finally passed in a direction at right angles to that in which it had
been passed under the former tool Figs. 6 and 7. In some cases it is found sufficient
to pass the plate only under the one tool Figs. 8 and 9.
It will be seen that these tools consist of a number of square plates which have
their corners rounded off and are clamped together on a spindle, in the one case, as
shewn in Fig. 6, with space discs between them, and in the other case, as shewn in

page_text: Fig. 8, almost close together. Before subjecting the plates to the burring tool it
is of advantage to heat them so as to render the metal somewhat softer and more
ductile.
We are aware that it has been proposed to form grid plates for secondary batteries
with ribs having lips projecting inwardly towards the cells of the plates, and we
therefore make no general claim to this construction, but, having now particularly
described and ascertained the nature of this invention and in what manner the
same is to be performed, we declare that what we claim is :-
:―
The manufacture of grid plates for secondary voltaic batteries by casting them with
ribs of depth greater than the thickness of the finished plate, and burnishing down
the edges of the ribs so as to produce burrs or lips projecting inwardly towards
the cells into which the plate is divided, substantially as and for the purpose
set forth.