IMPROVEMENTS IN SAFES AND SIMILAR STRUCTURES
Year: 1875

page_text: PROVISIONAL SPECIFICATION left by Robert Eduard Gustav Neumann
at the Office of the Commissioners of Patents, with his Petition,
on the 19th November 1875.
I, ROBERT EDUARD GUSTAV NEUMANN, of Koenigsberg, in Prussia,
Safe Manufacturer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN SAFES AND SIMILAR STRUCTURES," to be as follows:-
The object of this Invention is to make safes and similar structures
absolutely proof against fire and burglars.
-It
A safe constructed according to this Invention is as follows:-
consists of an outer iron box or shell made of iron plates about 3:2™m
thick, and rivetted together by angle iron about 58.8 by 4.9mm thick.
Inside of this iron box there is an entire steel lining about 1.6 to 3.3™
thick, and inside of this an iron box about 1.6mm thick. These three
thicknesses are made quite straight and even, and are united by rivets
passing right through. The steel lining is so hardened as that it cannot
be got through or otherwise demolished; for this purpose it is made
with parts or stripes about 10mm wide (about % of an inch) of alternate
different degrees of temper or hardness, so that in an attempt to destroy
this lining the harder parts or stripes spring, while the softer ones resist.

page_text: On the other hand when trying with a centre bit or similar tool a soft
stripe, if the tool accidently comes right on such a one, might be drilled
through, while the adjoining hard parts or stripes would resist every
attempt at making a hole larger than 10m at best. In order to give
this peculiarly hardened steel plate still greater strength an inner iron
plate box is placed behind it, and rivetted to it. Inside of the last
named iron box there is a space about 70 to 90mm wide filled with ashes
or other non-conducting material, and inside of this space there is an
inner or second iron box, say, 3 thick, and held together by angle iron
say, 2.6mm by 3.2mm thick. Inside of this iron box there is a steel wall
made of hardened discs overlapping like scales, and inside this again an
iron box about 1.6mm thick, the discs may be about 80mm diameter and
2mm thick, and are so overlapping that there is nowhere a free space
larger than 3m left, they are also so rivetted together that they can
turn freely on the rivet axes. Should any one drill through the iron
plate immediately outside this steel scale wall, then the scales will turn
and thereby cause the breakage of the boring tool. If it be attempted
to drill through one of the scale rivets, the scale would still keep some-
what in its place, and offer the desired resistance, hence it will be
impossible to get rid of one or more of the scales.
For larger safes a third inner box may be used at a distance of
about 26 from the last named box, this space would form an air space
for greater protection against fire; this last or third box may have
similar steel construction to the first or second box. All three boxes
are united at the door opening, and afford free spaces all round. The
door has a hoop iron encircling frame, outside of which is the aforesaid
air space.
The front of the door consists of two iron plates with
intervening steel plate like the outer box of the safe. The door and
the safe itself at the door have strong iron framings all round, say, 3.5mm
thick.
The non-conducting material aforesaid may be asbestos or sifted hard
wood charcoal ashes burnt in iron retorts.
The safe is according to size shut by Brahma lock, or combination lock,
or otherwise.