IMPROVED MODE OF AND MECHANISM FOR FORMING UNDERGROUND CONDUITS
Year: 1884

page_text: I JOHN HENRY JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of said Invention for "IMPROVED MODE
OF AND MECHANISM FOR FORMING UNDERGROUND CONDUITS" to be as follows:-
This Invention consists in forming an underground conduit in a trench by the
continuous packing of cement or other equivalent material round a former within
a tube which retreats as the continuous packing proceeds, the conduit thus formed
remaining in the trench.
The nature of the invention will be more readily understood by briefly
describing in the first instance a mode heretofore practised of forming under-
ground conduits. According to the said mode a plate or base of which a tube
formed a part, was placed on the bottom of a suitable trench, and cement
introduced through a hopper was packed by a piston within the tube and round a
former which was attached to the said plate or base. The plunger was arranged to
slide on the former a reciprocating motion being imparted to the said plunger by a
lever pivoted to the basc. As the cement was packed by the plunger the base with
the tube, hopper, former, plunger and mechanism for operating the same retreated
and left behind a cement conduit on the bottom of the trench.
The main object of the present invention is to pack the cement more uniformly
than can be done by the above described machine.
A tube the interior of which determines the diameter of the exterior of the
conduit, is attached to or forms part of a suitable base, and communicating with
this tube is a hopper. The base is provided with steadying flanges.
A tubular screw shaft fitting is on the former so as to turn freely thereon and
has a bearing in any suitable standard secured to the base the spiral rib or thread
of the screw shaft being adapted to the interior of the tube so as to be rotated
freely therein.
The thread of the screw shaft may be in sections like the blades of a propeller,
but the general character of the thread and its pitch will in a measure depend upon
that of the cement or concrete used.

page_text: The former or core is in this instance secured to the standard and the tubular
shaft is geared by bevel wheels to a vertical driving shaft which has its bearing in
the standard and which is provided with a hand wheel but the Invention is not
limited to this means for operating the shaft as any other suitable kinds of
operating mechanism may be employed.
It is essential in all cases, however, whatever may be the character of the driving
gear, that the entire machine should be self-contained or in other words that the
base should carry all the hereinbefore mentioned parts.
Sometimes a conduit with a lining tube is required, in which case this lining tube
becomes the former round which the cement is packed; the said lining tube passing
through the tubular shaft and not being connected to the machine is left behind in
the conduit of which it forms a part.
According to another modification of the machine the screw is formed on a shinft
which need not be tubular, an extension of this shaft beyond the screw constituting
the former which moves back with the machine, the only difference between the
action of this machine and that of the improved machine having an independent
forner being that in one case the former revolves in the packed cement, while in
the other case the former does not revolve.
As the screw shaft is turned the cement will be packed by a continuous operation
proper density of the packed cement being assured by the resistance which the
machine presents to the action of the screw.
"
In referring to cement the term is intended to apply to any material or
composition, granular, plastic or semi-plastic, which can be compressed into tubular
form in the manner described and will subsequently become hard.

page_text: I, JOHN HENRY JOHNSON of 47 Lincolus Inn Fields in the County of Middlesex
Gentleman do hereby declare the nature of said Invention for "IMPROVED MODE
OF AND MECHANISM FOR FORMING UNDERGROUND CONDUITS" and in what manner
the same is to be performed to be particularly described and ascertained in and by
the following statement:-
"
This Invention consists in forming an underground Conduit in a trench by the
continuous packing of Cement or other equivalent material round a "former
within a tube which retreats as the continuous packing proceeds the conduit thus
formed remaining in the trench.
The nature of the Invention will be more readily understood by briefly
describing in the first instance a mode heretofore practised of forming under-
ground conduits, reference being had to Figure 1 of the accompanying drawing.
A plate or base A of which a tube A' formed a part, was placed on the bottom
of a suitable trench and cement introduced through a hopper E was packed by a
piston D within the tube and round a "former" B attached to the base A. The
plunger D was arranged to slide on the former, a reciprocating motion being
imparted to the said plunger by a lever W pivotted to the base. As the Cement
was packed by the plunger, the base A with the tube, hopper "former plunger
and mechanism for operating the same retreated and left behind a cement conduit
on the bottom of the trench.
The main object of the present Invention is to pack the Cement more uniformly
than can be done by the above described machine.
Figure 2 of the accompanying drawing is a side view mainly in section and
Figure 3 a transverse section of the machine which is preferred in carrying out the
present Invention Figures 4 and 5 representing modifications of the machine.
A tube A (Figures 2 and 3) the interior of which determines the diameter of
the exterior of the conduit is attached to or forms part of a suitable base A and
communicating with this tube is a hopper F. The base A is provided with
steadying flanges xx as shown in Figure 3.
A tubular screw shaft G fitting on the "former" B so as to turn freely thercon
has a bearing in any suitable standard H secured to the base A the spiral rib or
thread w of the screw shaft being adapted to the interior of the tube A so as to bo
rotated freely therein.
The thread of the screw shaft may be in sections like the blades of a propeller,
but the general character of the thread and its pitch will in a measure depend upon
that of the cement or concrete used.
"3
The former or core B is in this instanco secured to the standard H and the
tubular shaft G is geared by bevel wheels m and n to a vertical driving shaft P
which has its bearing on the standard H and which is provided with a hand wheel y
but the Invention is not limited to this means for operating the shaft as any other
suitable kinds of operating mechanism may be employed.
It is essential in all cases however whatever may be the character of the driving
gear that the entire machine should be self-contained or in other words that the
base should carry all the hereinbefore mentioned parts except as hereinafter stated.
Sometimes a conduit with a lining tube is required in which case this lining tube
becomes the former round which the cement is packed thus in Figure 4 the said
lining tube B¹ passes through the tubular shaft G and not being connected to the
inachine is left behind in the conduit of which it forms a part,

page_text: According to another modification of the machine shown in Figure 5 the screw is
formed on a shaft B2 which need not be tubular an extension b of this shaft beyond
the screw constituting the former which moves back with the machine, the only
difference between the action of this machine and that of the machine shown in
Figure 2 being that in one case the former revolves in the packed cement while in
the other case the former does not revolve.
As the screw shaft is turned the cement will be packed by a continuous operation
proper density of the packed cement being assured by the resistance which the
machino presents to the action of the screw.
In referring to "Cement the term is intended to apply to any material or
composition granular plastic or semi-plastic which can be compressed into tubular
form in the manner described and will subsequently become hard.
Having now particularly described and ascertained the nature of said Invention
and in what manner the same is to be performed I declare that what I claim is
1 The mode herein described of forming underground conduits the said mode
consisting in the continuous packing of cement round a "former" within a
tube which retreats as the continuous packing proceeds substantially as
hereinbefore described.
2nd A conduit making machine in which the following elements are combined
namely first a basc A, tubo A' and hopper communicating therewith
second, a shaft carried by the base and having a spiral rib or screw thread
adapted to the interior of the tube, third a former" round which the
cement is packed and fourth mechanism for operating the said screw shaft
all substantially as hereinbefore described,