IMPROVEMENTS IN THE MANUFACTURE OF PIPES OR HOLLOW ARTICLES FROM PLASTIC MATERIALS
Year: 1853

page_text: PROVISIONAL SPECIFICATION let by Mark Sprot, junior, and
Robert Denholm, at the Office of the Commissioners of Patents,
the Datition on the 0th Tule 1859
PROVISIONAL SPECIF
by Mark Sprot, Jumor, and
Robert Denholm, at the Office of the Commissioners of Patents,
with their Petition, on the 0th Tuly 1852
(Void by reason of notice to proceed not having been given within the
time prescribed by the Act.)
We, MARK SPROT, junior, of Garnkirk, in the County of Lanark,
North Britain, Gentleman, and ROBERT DENHOLM, of the same place,
Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN THE MANUFACTURE OF PIPES OR HOLLOW ARTICLES FROM
PLASTIC MATERIALS" to be as follows:-
This Invention relates to the manufacture of pipes and tubular
articles from clay or plastic materials, wherein the sockets or end
junction pieces of such articles are formed at the time of moulding or
shaping the plain portion of the pipe or other article being made.
According to one modification of the apparatus used for this purpose
the clay is fed into a pug mill in the usual way, the spindle of such
mill having knives and screw or inclined blades interspersed through-
out its length. The end bearing or transverse bridge carrying the
bearing for the spindle is set considerably back from the die end of
mill, so as to allow of a knife action in between the bridge and
the pug

page_text: the die. In this way the clay is well worked and mingled together
after passing the bridge, and it enters the die in a fully mixed state.
To the delivering end of the pug mill or containing cylinder is at-
tached the mould for the intended socket of the pipe, within which is
placed a core bar made to suit the shape of the intended pipe and
socket. The projecting end of the pug mill spindle is fitted with a
loosely attached conical or inclined core piece, the conical face of this
being set towards the pug mill side, whilst the expanded end fits over
the end.of the core bar. As the pug mill spindle revolves the clay is
worked down through its chamber, and is directed over the conical face
of the loose or revolving core on the spindle end. This brings the clay
to the annular space between the core bar end and its surrounding
socket, and the plastic material is thus forced out through this space,
whence it issues by an annular space corresponding to the diameter of
the main portion of the pipe at the outer end of the socket. In this way
as the moulding goes on all the clay is first passed through the socket
mould, and it is then compressed into the size necessary for the plain
part of the pipe, in which state it constantly oozes out as the moulding
goes on, and thus any length of plain pipe may be made. When the
required length has been formed the operation is suspended, and the
clay left at the moment of stopping in the socket mould of course
becomes the completed socket for the pipe: The workman then severs
the clay at the end of the die, and removes the pipe and its core so as
to detach the newly formed pipe. The parts are then replaced, and the
operation goes on as before. The core bar is supported on an end
centro or a lever arrangement or other suitable adjustable support.
Instead of the pug mill arrangement the direct pressure of a steam or
water cylinder may be used to force the clay through, all the known
plan of forcing clay being equally applicable to this arrangement.