IMPROVE- MENTS IN HAMMERS WORKED BY ATMOSPHERIC PRESSURE
Year: 1857

page_text: PROVISIONAL SPECIFICATION left by Ferdinand Jossa at the Office
of the Commissioners of Patents, with his Petition, on the 27th May
1857.
I, FERDINAND JOSSA, of St. Helen's Colliery, near Bishop's Auckland,
Durham, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN HAMMERS WORKED BY ATMOSPHERIC PRESSURE " to be as follows:-
This Invention consists of an arrangement of machinery for working hammers
for various industrial purposes, by means of condensed or compressed air, and
by a vacuum.
The machinery consists of a bored cylinder, closed at the top and open
at the bottom, in which a portion is fitted air-tight of a piston rod carrying the
hammer, which strikes on an anvil. About two inches below the cover
of the cylinder a two-inch pipe enters, which is connected by a curve upwards
in the pipe with a metal chamber four feet in diameter, and ten feet long,
having hemispherical ends; the bottom of the pipe has an open mouthpiece;
a junction pipe is bored, and contains a piston fitted air-tight. In connection
with the metal chamber or receiver is an air machine, which resembles cylin-
drical bellows, differing from them only that the valves open (opposite to each
other) in opposite directions; this air machine (or air pump) may be worked
by a water wheel or steam power, and produces in the receiver a vacuum. By
pressing down a lever the piston is also moved downwards, the air rushes from

page_text: the cylinder into the exhausted receiver, which is two hundred times larger
than the cylinder of the hammer, and the hammer is then raised by atmo-
spheric pressure; the pipe from the receiver ending two inches below the
cover, the piston cannot reach' the latter, because air which is there compressed
sends the hammer back to the pipe. When required the lever is let go,
or moved upwards, the air enters immediately into the cylinder again, and
effects a falling of the hammer.
By means of the lever both the number and height of the strokes may
be regulated; the lever continuing in a midway position, the connection with
the receiver, as well as the accession of air to the cylinder, is stopped, and the
hammer remains stationery. Through the raising of the lever the hammer
may be raised its whole height, or may be dropped from any desired height;
if a regular working of the hammer be required, the lever may be moved by
means of an eccentric driven by steam or water power.
Supposing that the machine varifies to half atmospheric density each square
inch of the piston will lift seven pounds and half. To a hammer of three
hundred pounds, therefore, forty inches piston surface, or seven inches diameter,
is required, wherefore, naturally, a diameter something larger must be chosen.
To observe the grade of rarefaction an open quicksilver manometer is fitted
to the chamber or receiver.
The described arrangement is also practicable for smaller hammers, where
a number may be worked by one pump and one receiver; it is equally appli-
cable to stamps, markers, wires, nails, bronze, and other manufactories, where a
whole row of them can be set in motion by one common receiver.