Improvements in Electrical Accumulators or Storage Batteries.
Year: 1898

page_text: PROVISIONAL SPECIFICATION.
Improvements in Electrical Accumulators or Storage Batteries.
We, ANDREW GEORGE ADAMSON, Electrical Engineer, and THOMAS WILLIAM
ALLAN, Electrician, and ALLAN & ADAMSON, LIMITED, Manufacturers, all of
88&90, Tabernacle Street, London, E.C., do hereby declare the nature of this
invention to be as follows:-
Our invention relates to improvements in the construction of hollow frame
supports for the active material in electrical accumulators or storage batteries.
Hitherto supports or plates of this construction, having their sides connected
together by lattices, have had the inner surfaces of the lattices flattened against
the core of the mould in which they were cast, whilst, in order that the casting
might readily leave the mould, the edges of the lattices required to taper towards
the outer surface of the frame. When, therefore, the frame was finally filled
with the active material or paste, which it was absolutely necessary should
be brought parallel with the outer surface of the lattices, the effect, owing
to the outward taper of the lattices, was not so much to lock the active material
in the frame (which is the real function of the frame) as to lock the lattices in the
active material. Now when an accumulator plate is being either discharged or
charged with electricity heat is evolved both in and around it, and the difference of
expansion between the metallic frame and the active material being considerable,
the consequence is that the lattices expanding, burst the active material outwards
in cakes of considerable thickness. These falling between the plates, short circuit
the cells and destroy them. The object therefore of our invention is to obviate
these objectionable features by casting the hollow frame in such a manner that
the inner surfaces of the lattices shall be of less area than the outer surfaces.
This, it will be readily seen, will effectually lock the active material inside the
frame, and, on expansion taking place, the active material will not be in any way
liable to injury from the cause mentioned.
In order to accomplish the casting in one piece of a hollow frame having its
sides latticed as described, we construct a mould, the outer case of which is, as
is common, in two halves or sections but the core is composed of three or more
parts whose combined diameters or thickness is just equal to that of the
inside, of the outer case. The inside walls of the outer case, instead of having
the lattice or design to be cast hollowed out on their surfaces, are flat and solid,
whilst the grooves which form the lattices or design to be cast are cut into, or
otherwise arranged on the two outer sections of the core.
The third or centre section or sections of the core must be of such diameter or
thickness that when withdrawn from the mould after the frame is cast the two
outer sections whose combined diameter or thickness is less than the internal
diameter or thickness of the frame or casting, shall be free to drop away from the
lattices and be withdrawn.
The frame may be cast with one set of cores or with two or more sets placed
slightly apart so as to form central or sectional bars to strengthen the plate

page_text: outer sections whose combined diameter or thickness is less than the internal
diameter or thickness of the frame or casting, shall be free to drop away from the
lattices and be withdrawn.
The frame may be cast with one set of cores or with two or more sets placed
slightly apart so as to form central or sectional bars to strengthen the plate
mechanically and aid in conveying the current.
In order that our invention may be properly understood and readily carried into
effect we have hereunto appended one sheet of drawings of which,
Figure I is a side elevation of the frame.
Figure 2 is an end section of the frame on line M, N.
Figure 3 is an elevation of the mould opened with one half of the outer case
removed.
Figure 4, is an end section of the mould on line A, B.
The mould consists of an outer case in two halves and a core composed of three
or more parts. C, Figure 3 shows the upper surface of one of the outside cores
upon the surface of which are grooved the spaces L into which the lead runs to
form lattice. E shows the bottom block of the centre core. F, F1 and F2 are
pins which fit into the counter part or other half of the outer case of the mould in
order to keep the parts accurately in position for casting. G is the opening down
which the lead is poured and in which the lug of the frame is cast. Ĥ and H' are
the two respective parts of the outer case. Cand are respectively the two outer
.cores. These are held in position with the central core E and when the two
sections Hand H¹ of the outer case are tightly clamped the centres of the diamond
shapes of the two outer cores C and 1) are pressed tightly against the inner walls
of H and H, thus preventing the molten metal from running except in the
grooves L which form the lattices.
J, J, J, represent pins which when the mould is closed secure all three cores in
position. After the casting has taken place section H of the outer case of the
mould or whichever section bears the pin J is removed, the central core E with-
drawn, and a slight tap on the surface of C or D drops that section of the core on
to the back of the other one and it is then easily withdrawn. A similar action on
the other side of the frame releases the opposite outer core which may be also easily
withdrawn.
L shows a section of the lattice as it is proposed to be made, but of course we
may make it in any particular shape which we may find convenient.
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: -
The construction of the frame or support for the active material of an ac-
cumulator or storage battery as a hollow frame having lattices with bevelled, round
or concave surfaces extending across its sides and having the bevelled, round
or concave surface of these lattices on the inside of the frame, so that the paste will
be effectively locked in as well as supported, the whole frame, lattices and lug
being cast in one piece in any suitable metal or alloy, substantially as described.
Dated this 13th day of October 1898.
BOTTOMLEY & LIDDLE,
154, St. Vincent Street, Glasgow, Applicants' Patent Agents.