Improvements in Rivetting or other Pressure Machines.
Year: 1889

page_text: Date of Application, 5th D-c., 18.9-Accepted, 25th Jan., 1890
COMPLETE SPECIFICATION.
Improvements in Rivetting or other Pressure Machines.
I, CASPAR PAUL SCHUMACHER (commonly known as Caspar Schumacher) of the
firm of L. W. Breuer, Schumacher & Co. of Kalk near Cologne in the German
Empire, Manufacturer, do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
This invention relates more particularly to that class of machines in which the
final pressure is exerted by hydraulic power as in certain kinds of rivetting and
shearing machines.
In order that my invention may be clearly understood I will describe it as
applied to a portable rivetting machine, as from such description its application
to shearing, punching and like apparatus will be readily understood.
In the accompanying drawings which form part of this specification:
Fig. 1 represents a front elevation of a portable rivetter.
Fig. 2 represents a side sectional elevation on the line xx.
Fig. 3 is a top or plan view, and
Fig. 4 is a sectional elevation showing
cylinder.
a vertical instead of a horizontal main
To the framework A of the machine are attached the working cylinders B. C.
The piston works in the larger cylinder and carries a hollow piston rod b
In cylinder C, however, there is a
which acts as the piston for cylinder C.
stationary hollow piston d which opens through port e with the hydraulic
cylinder D. The other end of the piston d projects into the hollow piston rod_b
which is filled with the liquid it is desired to employ for operating the piston E.
When the piston a moves forward the contained liquid in bis driven out through
the hollow of the piston d and port e into the hydraulic cylinder D. The pressure
exerted on piston E will of course depend upon the area of the respective pistons as
well as on the initial pressure exerted on piston a.
The compressed air or other motive power is first admitted through the port of
cylinder C (which is always open to the source of supply) and will cause pistons b
and a to be forced back to the end of their stroke and at the same time pistons b, d
and port e will be filled with liquid from above piston E, the exhaust from behind
piston a passing out through pipe i and valve g.
When a forward stroke is desired, valve g actuated by lever his turned so as to
which
open communication through pipe i from cylinder C to the back of piston a,
having a much larger area than the end of piston b, overcomes the pressure thereon
and travels forward forcing the liquid contained in pistons band d through port e,
thereby pressing down piston E which carries the piston rod F and movable rivetting
tool G.
The hydraulic cylinder D which is of course securely attached to the framework A,
has an upper liquid chamber H with which communication can be opened by means
of a valve j.
The piston rod F of the large hydraulic piston E has on its rear side a toothed bar
or rack gearing with a pinion 1, having upon its axis the lever for working the same
by band for opening and shutting of the rivet jaws to seize and hold the rivets before
and after the final pressure has been applied, as by this means the requisite stroke of
the hydraulic piston E under full pressure is reduced to a minimum. If piston rod F
be thus lowered to its work by hand the valves j will be opened and sufficient liquid
admitted to keep the top of cylinder D and pistons d and b full so that when the rivet
lies gripped between the two rivets jaws, all the cavities that intercommunicate to
produce the hydraulic action are full of liquid.

page_text: During the return stroke of the piston a the lever h presses on the stem of valve j
so that the liquid immediately above the hydraulic piston E may be not only
sucked back again into the piston rod b, but any excess may also pass back to
chamber H.
When the lever his raised to admit the motive power behind piston a the valvej is
closed by means of the spring, and is then held firmly to its seat by the pressure
produced, so that no further quantity of liquid can pass into chamber H, and the full
hydraulic pressure can be exerted.
The construction of apparatus as before described obviates many of the disadvan-
tages incident to the use of the hydraulic rivetters as now generally constructed
particularly those of the portable description when employed in exposed positions as
the liquid used for actuating piston E is not discharged to waste and may consequently
be composed of glycerine or other non-freezing compound.
The motive power may be of any suitable kind such as compressed air, steam, or
water, but the two last named are not so advantageous in exposed places as the steam
is of course likely to be condensed and the water to freeze.
In cases where compressed air, steam, or water under pressure cannot be conveniently
obtained, the motive power may be carbonic acid gas generated at the point of use in
any convenient manner, suitable means being taken to secure the desired pressure.
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. In apparatus of the class described the combination of the pistons a band d
arranged to transmit the hydraulic pressure to operate the hydraulic piston E, sub-
stantially as subscribed.
2. In apparatus of the class described the combination with the operating valve of
a lever adapted to act upon the valve of a liquid supply chamber substantially as and
for the purposes set forth.
3. In apparatus of the class described the combination with the piston rod F of an
actuating lever whereby the material to be acted upon may be gripped prior to the
pressure being applied, substantially as set forth.
4. In apparatus of the class described the arrangement and combination of parts
whereby the movement of the pistons when under full pressure is reduced to a
minimum substantially as set forth.
Dated the 5th day of December 1889
PHILIP M. JUSTICE,
55 & 56, Chancery Lane, London, Agent for the Applicant.