Improvements in the Manufacture of Leaden Plates for Secondary Batteries or Accumulators, and in Moulds and Tools to be Employed in such Manufacture.
Year: 1899

page_text: Date of Application, 10th Aug., 1899
Complete Specification Left, 11th June, 1900-Accepted, 10th Aug., 1900
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Leaden Plates for Secondary
Batteries or Accumulators, and in Moulds and Tools to be
Employed in such Manufacture.
I, PHILIP JOHN DAVIES, of 78, Earl's Court Road, Kensington, in the County
of Middlesex, Plumber and Hydraulic Engineer, do hereby declare the nature
of this invention to be as follows:-
This invention relates to an improved process for manufacturing leaden
plates for secondary batteries or accumulators, and to improvements in moulds
and tools to be employed in such process and the main object of the invention
is to produce such plates with speed, perfection and economy, especially those
known as "Leitner" plates, which on account of their thinness and lightness,
have heretofore been made or built up by hand labour only, by placing a thin
sheet of rolled and perforated lead between other thin strips of lead which serve
as a kind of stiffening border, or stiffening border and lugs, and then burning
the edges or parts together by means of an electric current, the aero-hydrogen
blow-pipe or otherwise. This process involves considerable labour, care, and
great accuracy of manipulation that is not always attainable.
Owing to the extreme thinness of these plates it is extremely difficult to pro-
duce them by the ordinary well known process of casting, without having a
great many wasters.
But according to my present invention I cast the plate in a specially con-
structed mould which is maintained at a femperature approximating more or
less closely to that of molten lead, while the casting is being effected, and is
then cooled as rapidly as possible to enable the cast plate to be removed from
the mould. Or in some cases instead of casting the entire plate I place sheet
lead in the mould and cast on to it the necessary borders, lugs. or other projec-
tions. In cases where the plate is required to be so thin that it cannot be cast
of the desired thickness direct, I first produce a plate by one or other of the
above described processes thicker than is required, and then roll it out or press
it to the required thickness by suitable machinery. The holes or perforations
in the plates intended to hold the active paste may be cast in the plate or made
afterwards by suitable machines or tools.
An important part of my present invention relates to the construction of the
mould with certain pouring grooves or channels to convey, regulate, and direct
the hot fluid lead thereto and also to the means of heating and cooling the mould
and plate, all in order to enable the plates to be made by casting with greater
ease, certainty and economy than heretofore.
The mould is preferably made of brass plates with or without a number of
studs or projections thereon to produce the necessary holes in the cast lead plates
and with the outer margins of the mould plates sunk or recessed to produce
the necessary borders, raised parts or lugs on the plates or lead castings, and in
some cases to form the necessary pouring holes of the mould. In the mould

page_text: and round outside the said sunk or recessed parts intended to form the said
borders and so forth are preferably formed runners or pouring grooves some-
what of a pear-shaped section comparatively wide at the back or outer part and
narrowing towards the inner part where it connects with the said sunk or recessed
parts of the mould, so that the molten metal issues- from the runners in thin
streams all round the mould. converging inwards towards the centre thereof
where the said streams meet together and form a complete sheet or plate not-
withstanding that the mould may be studded with projections to produce the
perforations in the cast plate.
The plates of the mould may be made of any suitable material but so far
as I am at present aware brass is the best material to employ, though when
non-perforated plates are to be produced I sometimes employ lithographic stone
because it is not so good a conductor of heat as metal.
I sometimes force the molten metal into the mould by mechanical means
but I find in practice that a runner head of from 18 to 24 inches in height is
sufficient to ensure sound castings.
In order to work these moulds with facility and speed I preferably fix them
on a kind of casting table in a vertical or somewhat slanting position in order
to ensure the molten lead going straight down the abovementioned runners or
pouring grooves in order that it may not cool materially before it gets to the
bottom of the mould, for if it were to do so cool portions of the lead would get
into the body of the mould too soon, and cause the plate or casting to have what
are known as "cold shuts "which would make them useless for the intended
purpose.
In order to heat the mould before and while casting the lead plates, and to
cool the same after the casting has been effected, I form a heating and cooling
chamber between the mould and a bracket plate by means of which it is fixed
to the casting table, and I heat this chamber with one or more Bunsen or
other suitable burners so adjusted and regulated as to heat and the mould before
and while casting to a temperature of about 600° Fahrenheit, and I then after
casting cool this chamber and the mould with jets of air or other cooling material
to about 400° or 500° Fahrenheit. The alternate heating and cooling of the
mould may be effected by automatic or hand regulation of the heating and cool-
ing appliances.
It will be understood that the heating arrangements facilitate the running
of the lead freely into all parts of the mould and the cooling arrangements effect
a quick chilling of the plate to enable it to be taken out of the mould without
loss of time.
The moulds are preferably worked on a frame having two sliding Vees or
their equivalents, whereby rapidity of operation is attained, which is a very
important feature not only from an economical point of view, but as regards
soundness of the castings.
When the plates have been cast the runners may be cut off by any suitable
shearing devices or otherwise as may be found convenient, but I prefer to
employ for this purpose a novel construction of circular saw or saws having an
accurately fitted sliding table upon which I fix the plate with its runners and
make the same movable in such a manner as to carry the work to be done
accurately up to or between the saw or saws.
Sometimes, as for instance when qualified lead casters cannot be obtained
I proceed in a somewhat different way that is to say by what may be called a
semi-casting process. In this case I first cut sheets of lead to about the size
of the intended plates, these sheets may be either perforated or not; but if the
sheets are perforated, their outside edges ar preferably left intact. I then
suitably prepare the edges and fix the sheet of lead in the mould by suspending
it therein by studs or pins or otherwise and I then close the mould and heat
the outside edge parts thereof to nearly the temperature of molten lead, and
pour into the sunk or recessed parts of the mould molten lead, which unites

page_text: with the enclosed leaden plate and forms the borders thereon. Such a mould
may be of a simple character but preferably made with pear-shaped runners
or pouring grooves as above described. This method of working will, however,
be slow compared with that above described.
It is sometimes necessary to burr over the inside edges of the borders of the
plate to form a dovetail or key to hold the paste, this may be done by passing
the plate between rollers adapted to press the molecules of lead on the surface
of the border from the outside towards the inner part of the plate which not
only forms a burr or dovetail on the inner side of the border suitable for hold-
ing the paste, but also imparts rigidity to the metal itself. Instead of effecting
the burring operation by means of rollers it may be effected by means of burr-
ing or burnishing tools operated mechanically or by hand.
I sometimes form the necessary perforations in the plates after they are cast
instead of casting the perforations in them. This may be effected by means of
any suitable punching or perforating machine.
In some cases especially when the plates are required to be extremely thin, I
first form them by one of the processes above described somewhat thicker than
is required either with or without the perforations and with the border or frame,
and sometimes with border or frame and lugs, and then pass them through a
press or through a rolling mill provided with rollers having suitable recesses
or grooves made to correspond with the borders, lugs, or other thick or raised
parts of the plates in order to allow of the main body of the plate being pressed
or rolled out to the required thinness notwithstanding the presence of the said
borders, lugs or other thick parts formed on the plates. This rolling or pressing
may be done either before or after the perforation of the plate is effected, and
helps to impart rigidity to the plate.
P. J. DAVIES.
Per W. H. Beck,
115, Cannon Street, London, E.C., Agent.
Improvements in the Manufacture of Leaden Plates for Secondary
Batteries or Accumulators, and in Moulds and Tools to be
Employed in such Manufacture.
I, PHILIP JOHN DAVIES, of 78, Earl's Court Road, Kensington, in the County
of Middlesex, Plumber and Hydraulic Engineer, do hereby declare the nature
of this invention, and in what manner the same is to be performed, to be par-
ticularly described and ascertained in and by the following statement:-
"
This invention relates to an improved process for manufacturing leaden
plates for secondary batteries or accumulators, and to improvements in moulds
and tools to be employed in such process and the main object of the invention
is to produce such plates with speed, perfection and economy, especially those
known as "Leitner plates, which on account of their thinness and lightness,
have heretofore been made or built up by hand labour only, by placing a thin
sheet of rolled and perforated lead between other thin strips of lead which serve
as a kind of stiffening border, or stiffening border and lugs, and then burning
the edges or parts together by means of an electric current, the aero-hydrogen
blow-pipe or otherwise. This process involves considerable labour, care, and
great accuracy of manipulation that is not always attainable.

page_text: Owing to the extreme thinness of these plates it is extremely difficult to pro-
duce them by the ordinary well known process of casting, without having a
great many wasters.
But according to my present invention I cast the plate in a specially con-
structed mould which is maintained at a temperature approximating more or
less closely to that of molten lead, while the casting is being effected, and is
then cooled as rapidly as possible to enable the cast plate to be removed from
the mould. Or in some cases instead of casting the entire plate I place sheet
lead in the mould and cast on to it the necessary borders, lugs, or other projec-
tions. In cases where the plate is required to be so thin that it cannot be cast
of the desired thickness direct, I first produce a plate by one or other of the
above described processes thicker than is required, and then roll it out or press
it to the required thickness by suitable machinery. The holes or perforations
in the plates intended to hold the active paste may be cast in the plate or made
afterwards by suitable machines or tools.
An important part of my present invention relates to the construction of the
mould with certain pouring grooves or channels to convey, regulate, and direct
the hot fluid lead thereto and also to the means of heating and cooling the mould
and plate, all in order to enable the plates to be made by casting with greater
ease, certainty and economy than heretofore.
The mould is preferably made of brass plates with or without a number of
studs or projections thereon to produce the necessary holes in the cast lead plates
and with the outer margins of the mould plates sunk or recessed to produce
the necessary borders, raised parts or lugs on the plates or lead castings, and in
some cases to form the necessary pouring holes of the mould. In the mould
and round outside the said sunk or recessed parts intended to form the said
borders and so forth are preferably formed runners or pouring grooves come-
what of a pear-shaped section comparatively wide at the back or outer part and
narrowing towards the inner part where it connects with the said sunk or recessed
parts of the mould, so that the molten metal issues from the runners in thin
streams all round the mould converging inwards towards the centre thereof
where the said streams meet together and form a complete sheet or plate not-
withstanding that the mould may be studded with projections to produce the
perforations in the cast plate.
The plates of the mould may be made of any suitable material but so far
as I am at present aware brass is the best material to employ when non-per-
forated plates are to be produced I sometimes employ lithographic stone be-
cause it is not so good a conductor of heat as metal.
I sometimes force the molten metal into the mould by mechanical means
but I find in practice that a runner head of from 18 to 24 inches in height is
sufficient to ensure sound castings.
In order to work these, moulds with facility and speed I preferably fix them
on a kind of casting table in a vertical or somewhat slanting position in order
to ensure the molten lead going straight down the abovementioned runners or
pouring grooves in order that it may not cool materially before it gets to the
bottom of the mould, for if it were to do so cool portions of the lead would get
into the body of the mould too soon, and cause the plate or casting to have what
are known as cold shuts" which would make them useless for the intended
purpose.
"
In order to heat the mould before and while casting the lead plates, and to
cool the same after the casting has been effected, I form a heating and cooling
chamber between the mould and a bracket plate by means of which it is fixed
to the casting table, and I heat this chamber with one or more Bunsen or
other suitable burners so adjusted and regulated as to heat the mould before
and while casting to a temperature of about 600° Fahrenheit, and I then after
casting cool this chamber and the mould with jets of air or other cooling material
to about 400° or 500° Fahrenheit. The alternate heating and cooling of the

page_text: mould may be effected by automatic or hand regulation of the heating and cool-
ing appliances.
It will be understood that the heating arrangements facilitate the running
of the lead freely into all parts of the mould, and the cooling arrangements
effect a quick chilling of the plate to enable it to be taken out of the mould
without loss of time. It is obvious that the cooling arrangements may sometimes
be dispensed with, for example, when casting comparatively thick plates or
when great speed is not required for cooling.
The moulds are preferably worked on a frame of the kind referred to in the
Specification of a Patent granted to me and bearing date 24 Dec. A.D). 1890,
No. 21031, having two guiding Vees or their equivalents, whereby rapidity of
operation is attained, which is a very important feature not only from an
economical point of view, but as regards soundness of the castings.
When the plates have been cast the runners may be cut off by any suitable
shearing devices or otherwise as may be found convenient, but I prefer to employ
for this purpose a circular saw or saws having an accurately fitted sliding table
upon which I fix the plate with its runners and make the same moveable in such
a manner as to carry the work to be done accurately up to or between the saw
or saws.
Sometimes, as for instance when qualified lead casters cannot be obtained, I
proceed in a somewhat different way that is to say by what may be called a semi-
casting process. In this case I first cut sheets of lead to about the size of the
intended plates, these sheets may be either perforated or not; but if the sheets
are perforated, their outside edges are preferably left intact. I then suitably
prepare the edges (which process is well known to skilled plumbers) and fix
the sheet of lead in the mould by suspending it therein by studs or pins or
otherwise and I then close the mould and heat the outside edge parts thereof
to nearly the temperature of molten lead and pour into the sunk or recessed parts
of the mould molten lead, which unites with the enclosed leaden plate and
forms the borders thereon. Such a mould may be of a simple character but
preferably made with pear-shaped runners or pouring grooves as above described.
This method of working will, however, be slow compared with that above
described.
It is sometimes necessary to burr over the inside edges of the borders of the
plate to form a dovetail or key to hold the paste, this may be done by passing
the plate between rollers adapted to press the molecules of lead on the surface
of the border from the outside towards the inner part of the plate which not
only forms a burr or dovetail on the inner side of the border suitable for hold-
the burring operation by means of rollers it may be effected by means of burr-
ing or burnishing tools operated mechanically or by hand.
I sometimes form the necessary perforation in the plates after they are cast
instead of casting the perforations in them. This may be effected by means of
any suitable punching or perforating machine.
In some cases especially when the plates are required to be extremely thin, I
first form them by one of the processes above described somewhat thicker than
is required either with or without the perforations and with the border or frame,
and sometimes with border or frame and lugs, and then pass them through a
press or through a rolling mill provided with rollers having suitable recesses
or grooves made to correspond with the borders, lugs, or other thick or raised
parts of the plates in order to allow of the main body of the plate being pressed
or rolled out to the required thinness notwithstanding the presence of the said
borders, lugs or other thick parts formed on the plates. This rolling or pressing
may be done either before or after the perforation of the plate is effected, and
helps to impart rigidity to the plate.
And in order that the said invention may be fully understood I will now pro-
ceed to describe the same with the aid of the accompanying sheet of drawings.

page_text: In carrying my invention into practical effect I generally proceed as follows:-
First. I take two truly planed up pieces of cast brass A about 18 inches
long and 13 inches wide and dove-tail or dowel the same together, after which
I plane or otherwise form the inside surfaces of the plates to the shape shown
at R, Y, and X in the transverse section, Figure 1 of the drawings.
After the mould R, Y, X is formed on the faces of the beforementioned brass
plates I construct at their back or other parts an air or heating chamber as
shown at F, F, preferably by placing 8 distance pieces B B B all round the
sides and ends.
Through these distance pieces I run " or " gas pipes as shown at Q Q.
These pipes are preferably pierced in such a manner as to allow small jets of gas
to play upon the back or other part of the brass plates A of the mould. These
pipes are preferably placed every 3" apart up the mould, and supplied with gas
through Bunsen belt burners G G. EE are the outside plates preferably of
cast iron all bolted or screwed to the distance pieces and brass plates and
bracketed at the bottom in such a manner as to work upon a casting table with
suitable slides, for carrying the mould when it is required to open or close the
same, for taking the cast lead plates out. Such a casting table is illustrated
in the drawing annexed to the Specification of my Patent connected with the
manufacture of the Epstein plate No. 21031 of 1890 or in many other of the
specifications of my Patents for lead casting.
At suitable places in the back plates EEI form vent holes, to supply the
necessary air to the burners. The vent holes may be formed in the distance
pieces B B. Below each burner pipe I sometimes run a second line of piping,
similar to the gas pipes, but for conveying by force jets of cold air for the pur-
pose of mildly but rapidly cooling the brasses of the mould after the gas burners
have been turned out or the flames reduced, whereby I am enabled to quickly
take the casting from the mould. After the lead casting has been removed the
gases are relit or increased as the case may be, and in this way I can produce
large leaden plates as little as a quarter of a millimetre thick with thick border
edges in a quarter of the time required by any other means
Figure 2 is an elevation of what is known as the Leitner plate which is usually
perforated with round holes, the body part V being one millimetre thick for
the positives and a half a millimetre thick for the negatives. A¹ A¹ show the
border or frame part of the plate. L the lug, U represents D-shaped holes
with spur at the back and front as shown in Figure 7. The size of these plates
is usually 8 inches and about 5 inches wide, which if cast with perforations
are extremely difficult to cast in the ordinary way.
The dotted lines P P on the border (Figure 2) indicate the real line of the
inner part of the border and the line Y (Figure 2) indicates the bent-over edge
for the purpose of holding the active paste at the border of the plate. I may
say that the body or surface of this plate is half perforations, there being in
some types as many as 500 holes, but the one I prefer to make has about half
this number and consequently the holes are larger than when more holes are
employed.
Figure 3 indicates a cross section taken at T T of Figure 2 but with the
thin edges indicated by the arrows at Y Y Figure 3 as they leave the mould.
The
A¹ A is the border and 22 are the runners as they leave the mould.
body V in Figure 3 is shown unperforated.
Figure 4 is the same thing as Figure 3 but with the body perforated at 13
and the stand up edges Y Figure 3 turned down for holding the active paste
material as at Y Figure 4.
Figure 5 illustrates the plate in section with the border chamfered at A¹ A¹,
and the paste edges Y Y Y turned down on burred over, and the runners
removed.
Figure 6 illustrates in section the plate with the runners cut off but with
the paste edges not yet turned down or burred over. Figure 7 illustrates the plate

page_text: in section made by what may be called a semi-casting process, viz., I first mill
the body and perforate it, after which I cast the border A thereon. This
diagram also shows how I sometimes form spurs on the body of the plate and
which spurs are formed by punching or stamping, the shape of the holes being
that illustrated at U Figure 2 of the drawings. Such spurs greatly assist to
hold the active material or paste to the plate.
In practice I find it much better to run the border and body of the plate
solid, than with perforations, as with the punching operation I have less
difficulty in getting the metal to flow across the body of the plate than when
there is a number of cores within the mould. Besides by punching these plates
after they are cast it straightens them and gives them a uniform shape ready
for pasting.
Figures 8, 8,and 8b illustrate in side elevation, plan, and end elevation respec-
tively a convenient form of apparatus for cutting off the runners 2 from the
plates after they have been cast and removed from the moulds.
a are circular
saws suitably mounted on a spindle running in bearings c is a base or frame d,
and driven by a vee-pulley e, or in any other convenient manner. f is a car-
riage fitted to slide to and fro in suitable dovetail or other guides g on the
base or frame d, and adapted to receive on its upper surface one of the cast
lead plates, the runners 2 of which project over the side edges thereof. i is a
cover-plate the lower surface of which is adapted to lie on and fit closely to the
upper surface of the cast lead plate. j is an eccentrically headed lever for clamp-
ing the cover-plate i during the cutting operation. A plate having been placed
in position and secured therein by the cover-plate i and lever j, the overhang-
ing runners 2 are brought into contact with the rotating saws ve, and both the
said runners 2 are thereby expeditiously removed at one operation, close to the
borders A of such plate (see Figures 3 and 4).
Figure 9 illustrates one of a pair of rolls which I sometimes use for elon-
gating the beforementioned cast lead plates. It will be obvious that by the use
of these rollers can first cast the plates to about half a millimetre in thickness
and then by passing them through a pair of rollers with suitably formed edges
at K K and a suitable groove as indicated by the lines J for receiving the
border that I can reduce the substance of these plates to almost any degree,
which could not possibly be done by casting alone.
I, Figure 10, illustrates a roller with bevelled edges as at K2 K2 for bevelling
and also burring over the edges of the plate Figure 5. I sometimes provide this
roller Figure 10 with a recessed part as shown at J Figure 9.
Figure 11 shows an end view of a pair of rollers of segmental shape bounded
by the chords M M, and Figure 12 illustrates the same rollers with bevelling
edges C D. N N N are the bearings of the rollers. Such rollers may be worked
by any suitable powerful machinery.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I desire to state that
I do not here restrict myself to the precise details or materials which I have
had occasion to refer to, as the same may be greatly varied without departing
from the nature of my invention, nor do I claim making leaden plates of the
Leitner class as a casting generally, as I have made moulds for producing
such class of plates in various forms but such moulds are extremely difficult and
slow to manipulate and by their use a quantity of wasters are generally produced
to say nothing of the rotten state and extra drossing" to which the lead is
brought when subjected to excessive temperature and the uncertainty in the
running of the webs or bodies, especially when cores for the holes are formed
in the mould, but what I do claim is:-
66
First. Casting what is known as the Leitner lead plate or conductor in my
specially formed mould and afterwards perforating it, substantially as described
and illustrated by the drawings.

page_text: Second. Casting these plates with stand up spurs or edges Y on the borders
which spurs or edges are afterwards bent over for the purposes of holding the
edges of the paste or active material substantially as described with reference
to Figures 2, 3, 4, 5, and 6 of the drawings.
Third. The construction of the mould with the heating chamber substantially
as described with reference to Figure 1 of the drawings.
Fourth. The method of cooling the mould for casting these plates substan-
tially as described.
Fifth. Apparatus for removing the runners from lead plates, which apparatus
consists of two saws arranged and operating substantially as described with
reference to Figures 8, 9, and 10 of the drawings.
Sixth. Casting the beforementioned lead plates and then rolling them out
with rolls substantially as described with reference to Figures 9, 10, 11 and 12
of the drawings.
Dated this 9th day of June 1900.