Improvements in Pneumatic Hammers.
Year: 1899

page_text: Date of Application, 18th Dec., 1899-Accepted, 16th June, 1900
Improvements in Pneumatic Hammers.
I, WILHELM BERG, of Victoria Strasse 15, Kalk, Germany, Engineer, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed to be particularly described and ascertained in and by the following
statement:-
This invention relates to an improved construction of pneumatic hammers
which I will describe with reference to the accompanying drawing, in which
Figs. 1 and 2 shew vertical sections taken at right angles to each other while
Figs. 3, 4 and 5 shew enlarged details.
The pneumatic hammer has a working cylinder 6 which is connected to the
suction cylinder a above by means of a slide valve casing c.
The working cylinder 6 can by the motion of the slide valve be made to com-
municate with the suction cylinder through various channels in the slide valve
box in such manner as to effect the required functions of the hammer block.
Figs. 4 and 5 shew the different positions of the slide valve, and Fig. 3, shews
a detached underside plan of the same.
Assuming that the piston p has a continuous up and down motion imparted
to it, then when the slide is in the position shewn at Fig. 4, the air passes from
the working cylinder b through the channels de into the suction cylinder a and
back again, according as the piston p of the suction cylinder is making its up or
its down stroke; the effect of this is that the hammer block q is made to move in a
corresponding manner to the suction piston according as there is expanded or
compressed air over the hammer block, so that when, during working, the
piston p is in the raised position shewn at Figs. 1 and 2 the hammer block
would also be in the raised position. It only sinks gradually down into the
lowered position shewn by a gradual leakage of air past it into cylinder b, when
the machine has remained stationary for some time.
When the hammer block is to be held in its raised position, that is to say, put
out of action while piston p continues working, the slide is moved into the posi-
tion shewn at Fig. 5, by the hand lever n. The air then passes from the working
cylinder 6 through the channels d, f, r, g, h, into the suction cylinder a and
thence on the downstroke of the suction piston through the channels ei into the
chamber k of the slide valve box as the check valve t prevents the air from pass-
ing back into cylinder b.
From chamber ka portion of the air escapes through the valve o. The hammer
block g is thus held in its raised position while the suction piston p may con-
tinue to work, in which case it first produces a partial vacuum underneath it and
also in the chamber and then on the downstroke it compresses the remaining
air to atmospheric pressure again.
When the hammer is to operate again, the slide is moved back into the posi-

page_text: tion at Fig. 4, so that 6 again communicates with a through channels e and d,
consequently on the following downstroke of the piston p the air below it will
enter cylinder b again and the hammer will consequently descend, and on the
upstroke of piston p it will ascend again. Should it happen that the piston p
is in its lowest position and the hammer block q in its highest position at the
moment when the slide is moved into the position shewn in Fig. 4, air from
the chamber will pass through the passages i, m, f, r, g, h and through the
valve as the piston is raised, so that there will be sufficient air to work the
hammer. During such working the passage of any air back into the partially
exhausted chamber k through the passages h, g, r, f, m, i will be prevented by
the check valve t.
The valve o only operates as a discharge valve, firstly on starting the machine,
when, should the hammer block have sunk down into the position at Figs. 1
and 2, when it will have first to be raised by the pumping action of piston p,
discharging the air in a and b through o, and secondly in the event of there being
any excess of air when the hammer block is held in the raised position by shift-
ing the slide valve into the position at Fig. 5, as above described.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
-
1. A pneumatic hammer wherein there is provided between the working cylin-
der containing the reciprocating hammer block and the suction cylinder and
piston, a slide valve so arranged and combined with ports and passages that
according to one position of the valve the working body of air alternately passes
from the working cylinder directly into the suction cylinder, and then back again
into the working cylinder, while in another position of the valve the air is made
to pass first from the working cylinder into the suction cylinder and thence into
a chamber, without passing back into the working cylinder, so that the hammer
block is retained in its raised position, substantially as described.
2. The improved construction of pneumatic hammer combined and operating
as herein described with reference to the drawing.
Dated this 18th day of December 1899.
ABEL & IMRA 1,
Agents for the Applicant.