Hollow Graphite Bodies, and Press for the Production of the same.
Year: 1891

page_text: Date of Application, 5th Mar., 1891
Complete Specification Left. 5th Dec., 1891-Accepted, 9th Jan., 1892
PROVISIONAL SPECIFICATION.
Hollow Graphite Bodies, and Press for the Production of the same.
1, FRANZ ULRICH of Budweis, Austria, Manufacturer, do hereby declare the
nature of this invention to be as follows:-
The compression of the graphite bodies or blocks known in commerce is very
difficult to effect and much waste is caused by the fracture of the graphite in the
operation, to remedy which evil and at the same time to reuder the compressed
graphite more tenacious or durable is the object of the invention.
In carrying out the invention 1 employ a press composed of a stamp and a
mould into which latter the graphite powder is placed for compression. The
upper part of the stamp may be of any suitable cross sectional form but the lower
part thereof extending downwards from the upper part is somewhat of the form
of an inverted sugar loaf, that is to say, of a taper form rounded off at the
bottom.
The mould having been supplied with graphite powder the lower extension of
the stamp is pressed down into the same and presses the graphite both downwards
and laterally, distributing it equally within the mould. In this way the air present
in the graphite is expelled therefrom and readily escapes as the upper and larger
part of the stamp which nearly fits the mould does not enter the same until this
has been done when it is moved downwards and completes the compressing
operation, the double pressure of the lower and the upper part of the stamp
distributing the pressure equably through the graphite body.
Dated this 5th day of March 1891.
CAPITAINE & VON HERTLING,
89, Chancery Lane, London, W.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
Hollow Graphite Bodies, and Press for the Production of the same.
1, FRANZ ULRICH of Budweis, Austria, 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:-
The bodies composed of powdered graphite or black lead hitherto produced in
trade are all easily broken which renders their packing and transport difficult.
They do not present a good appearance. Hitherto the compression of such
material has always given a bad result as the surface of the pressed body cracks or
fissures and its hardness is uneven whilst it frequently happens that the pressed
bodies break upon being taken from the press.
In order to remove these disadvantages I employ a press such as is represented
in the accompanying drawing, Fig. I being a part sectional view thereof and
Figs. 2 and respectively a part sectional view and a horizontal section of a
modification thereof.
The press shewn in Fig. 1 consists of a stamp S of any suitable cross section
with an extension D projecting downwards from the pressing surface of S. The
dimensions of extension D must correspond to the required dimensions both as to
height and thickness of the object to be produced. F is the mould or form which
may be of any suitable shape.
The press shewn in Figs. 2 and 3 differs from that of Fig. 1 only in that the
stamp has three extensions D instead of one but it may also have any other
number of these.

page_text: To produce hollow graphite bodies by means of this press the mould Fis
supplied with graphite powder and stamp S with extension D brought down into the
same. The extension or extensions D press into the graphite sooner than the
pressing surface of stamp S thereby pressing the graphite simultaneously down-
wards and owing to the form of D-laterally. In this way the air present in the
graphite is completely expelled therefrom and readily escapes previous to the
stamp S entering the mould. When stamp S is moved further down it closes
the mould and presses with the whole force of the press the graphite mass K
together. As the air has been previously expelled and at the same time the
graphite equally distributed by the extension or extensions D the pressure is equal
throughout the whole cross section and no fracture or cracking can take place.
The operation is the same whether the press is that of Fig. 1 or Figs. 2, 3.
If it be desired to give the graphite bodies an especially brilliant surface the
mould is formed in two parts and so fixed in the press that both parts may be
turned round. In the case of a cylindrical form with rounded point (Fig. 2) of
graphite body, the mould is so constructed that the cylindrical part may be slid
over the point part s so that both parts of the mould together present the same
shape as that shen in Fig. 1. The pressing operation is performed as before
described only whilst the stamp S is still under pressure the parts as also the
part may be turned round. Such turning as the mould is of steel and the
moulding surface polished gives a highly polished surface to the graphite body
under treatment. For this purpose the form of stamp shewn in Fig. 2 is
particularly advareous as owing to the several parts D, corresponding ribs d
are formed with the hollow graphite body (Fig. 3) whereby this is held fast
when the moula is turned round. Undivided moulds F similar to that shewn in
Fig. 1 may also be turned round on the graphite body.
.
In all the said cases beautiful compact graphite bodies or objects are produced
which may be readily packed, transported and utilised.
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. Graphite bodies with one or more recesses or cavities for application as black
lead, substantially as described and shown.
2. In the production of hollow graphite bodies for use as black lead, stamp S
with one or more taper extensions D for expelling the air from the graphite
during the pressing operation and at the same time for securing a thoroughly
regular distribution of pressure and material, substantially as described and
shewn.
3. The production of hollow graphite bodies for application as black lead by
means of one or more stamp extensions D and with the mould or form F divided
or in one piece and turned round or not during the pressing operation, substantially
as described and shewn.
This 2th dox of Doomben 1001
CAPITAINE & VON HERTLING,
89, Chancery Lane, London, W.C., Agents for the Applicant.