Improvements in Cast Metal Worms or Archimedean Screws for Conveyors and Elevators and other purposes, and in the Method of Moulding the same.
Year: 1891

page_text: Date of Application, 6th Apr., 1891
Complete Specification Left, 1st Jan., 1892-Accepted, 6th Feb., 1892
PROVISIONAL SPECIFICATION.
Improvements in Cast Metal Worms or Archimedean Screws for
Conveyors and Elevators and other purposes, and in the Method
of Moulding the same.
I, THOMAS WRIGLEY of Waterside House, Todmorden in the County of York,
Mill Manager, do hereby declare the nature of this invention to be as follows:-
This invention relates to cast metal worms or archimedean screws for conveying
or elevating grain, flour, coal or similar materials, or for conveying or elevating
liquids, or other purposes and consists in an improved method of moulding said
worms or archimedean screws of cast metal and an improved form or construction
of the cast worms or screws.
The worms for conveying or elevating purposes have heretofore usually been
made of wrought iron tin plate or other sheet metal or of helical bars or rods in
various forms, which blades or rods are fixed upon a central shaft or upon the
outside of a hollow cylinder or tube. The worms thus made possess insufficient
strength where heavy materials have to be conveyed or elevated, or forwarded
against pressure, and if strongly made are expensive. Short worms for worm
wheel gearing cast of iron or other metal from patterns have hitherto invariably
been cast with the blades of the worm or screw at right angles to the shaft or
centre and also generally with broad and short blades considerably thicker at the
root than at the outer edge of the blade and have never been intended for and are.
quite unfitted for elevating or conveying purposes, and no worms or screws suitable
for conveying or elevating purposes have been hitherto cast either of great length
or large diameter with blades of uniform thickness or with the radial surfaces of
such blades inclined or curved to the axis, in consequence of the difficulties of
moulding them. The difficulties of moulding and casting screws or worms
suitable for conveying or elevating purposes are overcome by my improved method
of moulding said worms or archimedean screws, by means of which they can be
cast of large diameter in any desired length with blades if desired of uniform
thickness and also if desired with the radial surfaces of said blades inclined or
curved to the axis, instead of being at right angles thereto.
In carrying my invention into effect, I cut a pattern of the worm or screw in a
lathe or otherwise make the same of a length suitable to the pitch and diameter of
the worm required, for instance containing four or five turns or threads of the
screw. At one end of this pattern I form or attach a cylindrical part having the
same diameter of the screw or worm. For moulding the worn or screw I first
form a semi-circular mould of the same diameter as the worm pattern, by means of
an ordinary cylindrical or pipe pattern, of the length the worm or screw to be cast
is to have with addition of the cylindrical part of the pattern. I then place the
pattern into this semi-circular mould at one end of the same, and-ram in the .sand
round the bottom half of the pattern, then put on the top part of the moulding
box and ram in the sand about the upper half of the pattern in the usual-way.
When this has been done, instead of parting the box or sand in the usual way,
turn the worm pattern and screw it partly out of the sand along the semicircular
mould by means of the cylindrical part of the pattern which can slide along in
the semicircular mould, for instance if the pattern contains four turns or threads
of the screws, I turn it say twice round, whereby two threads will be screwed out
of the mould and two threads remain in the same. I then ram up the two threads
now exposed, those remaining in the sand serving to protect the emptied part of
the mould from damage, and proceed by repeating this operation until the required

page_text: length of worm has been moulded, providing the usual pouring and ventilating
openings and finishing the mould in the usual way.
Another mode of moulding is to attach to the pattern a shaft instead of the
said cylindrical part, such shaft being attached concentrically with the pattern
and of sufficient length to extend to the outside of the moulding box and to pass
through the end of the same and rest in a bearing attached to the moulding box
or fixed in a frame work at some distance therefrom concentrically with the mould.
The shaft is worked by hand or power driven machinery as may be desired, to
turn the pattern of the worm or screw and screw it along from one end of the
moulding box to the other and then out of said box through an opening provided
for that purpose, while the sand is rammed up successively in the manner herein-
before described.
By this method worms or archimedean screws of any desired length and of any
necessary diameter can be moulded and cast, with blades of uniform thickness
throughout or of varying thickness, and with the radii of said blades either at a
right angle or inclined or curved to the axis. The inclined or curved form of
blade, which has hitherto not been made of cast metal, in consequence of the
difficulties of moulding the same, possesses great advantages, making the worm
considerably stiffer and capable of supporting greater strains both in the longi-
tudinal and transverse direction, and bringing the material to be conveyed or
elevated towards the centre, thereby relieving the surrounding troughs or tubes
from pressure and reducing the friction of the materials on said troughs or tubes.
The said worms or screws may also be cast of any desired diameter or length
with a helical or spiral blade only and without a central part or shaft, the turn of
the spiral or helical blade or screw forming its own support.
Dated this 4th day of April 1891.
W. T. EMMOTT,
Agent for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Cast Metal Worms or Archimedean Screws for
Conveyors and Elevators and other purposes, and in the Method
of Moulding the same.
I, THOMAS WRIGLEY of Waterside House, Todmorden, in the County of
York, Mill Manager, 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 to cast metal worms or archimedean screws for conveying
or elevating grain, flour, coal or similar substances or for conveying or elevating
liquids or for other purposes and consists in an improved method of moulding said
worms or archimedean screws for casting them of iron steel or other metal and in
an improved form or construction of the cast worms or screws.
The worms for conveying or elevating purposes have heretofore been made of
wrought iron tinplate or other sheet metal or of helical bars or rods in various
forms, which blades or rods are fixed upon a central shaft or upon the outside of a
hollow cylinder or tube. The worms thus made possess insufficient strength where
heavy materials have to be conveyed or elevated or forwarded against pressure,
and if strongly made are expensive. Short worms for worm wheel gearing, or. for
screw piles cast of iron or other metal from patterns have hitherto been cast with
the blades of the worm or screw at right angles to the shaft or centre and alsö
generally with short blades considerably thicker at the root than at the outer edge
of the blade and have never been intended for and are quite unfitted for elevating
or conveying purposes. Worms intended for conveying purposes have been cast,
under various disadvantages, from patterns formed or cut up into sections, and

page_text: have also been cast in portions and afterwards fastened together on a central shaft
or otherwise but no worms or screws suitable for conveying or elevating purposes
have hitherto been cast in long lengths in a mould formed from a pattern all in one
piece and of large diameter with blades of uniform thickness or with the radial
surface or generatrix of such blades inclined or curved to the axis in consequence
of the difficulties of moulding them. These difficulties of moulding and casting
worms or screws for elevating and conveying purposes are overcome by my
improved method of moulding said worms or archimedean screws by means of
which they can be cast of large diameter and in any desired lengths up to 20 feet,
or even larger if required, although 10 or 12 feet lengths are most convenient in
use, and with blades if desired either of uniform or varying thickness and also if
desired with the radial surface or the generatrix of said blades inclined or curved
to the axis instead of being at right angles thereto.
The manner of carrying out my invention is described in the following
statement, reference being made to the two sheets of drawings appended hereunto.
I cut a pattern a Fig. 1, Sheet 1 of a worm or screw in a lathe or otherwise make
the same, the pattern having a length suitable to the pitch and diameter of the
worm required, for instance containing three or four turns or threads of the screw.
To one end of this pattern a I attach a cylindrical part in any convenient
manner, for instance by entering the projecting end of a shaft passing through
said cylindrical part into a socket a¹ of the pattern a and fixing it therein by
means of screws or equivalent means. This cylindrical part or guide is made of
the same diameter as the outer diameter of the screw or worm a.
For moulding
the worm or screw a moulding box is required such as is generally used for
moulding ordinary pipes, but with a round hole at each end when the boxes are
fastened together, slightly larger than the diameter of the worm or screw to be
moulded and the boxes also require to be longer than the length of the worm or
screw intended to be cast. I first form a semicircular mould of sand in the bottom
box Fig. 2 by means of a cylindrical or ordinary pipe pattern d, Figs. 2 and 3, in
the usual manner, the removal of said pattern d leaving the box cas shown by
Figs. 4 and 5 ready for the reception of the worm pattern. The pattern a is then
placed into the mould thus prepared, the cylindrical core pattern ƒ having first
been loosely placed upon the other end shank of the worm pattern a, as shown by
Fig. 6; the top box, Figs. 7 and 8, is then placed upon the bottom box c and
cottered fast to the bottom box as usual, and not removed until the casting is
complete. The sand is then rammed in round the pattern a and between the
blades or threads of the screw and the top box filled with sand and rammed down
in the part extending over a part of the worm pattern a, as indicated on Fig. 7.
When this has been done, the pattern a with the cylindrical guide is turned by
means of a spanner placed upon a square 2 on the end of the shaft of the
cylindrical guide band this guide b, together with the worm pattern a is thereby
partly screwed out of the sand and along the semicircular mould, the guide band
the pattern a sliding along the same but the loose core pattern being left in its
place, as shewn on Fig. 9, where the worm pattern is shown as having received
two or three turns and has consequently moved along the box a corresponding
distance whereby the pattern is withdrawn from the mould for the distance or
length hi, and the pattern a is still kept in the sand previously rammed in for the
distance k so that when the ramming in of the sand for the further length 1 k
Fig. 9 of the pattern a now exposed is effected the empty part hi of the mould
where the pattern a has left is not damaged thereby. After the length 1k has
been rammed up, the pattern is again screwed further out of the sand and the
foregoing operations are repeated until the desired length of worm has been
moulded, when the sand is rammed in over the cylindrical part b or a portion of
the same and the pattern a finally screwed out of the sand and through the opening
in the end of the boxes. The pattern is then removed, through the opening at
that end of the boxes and replaced by a sand or loam core, and a similar core
inserted into the hollow mould left by the cylindrical pattern b, at the other end

page_text: of the worm mould, and the moulds are provided with the usual openings for
pouring and ventilating.
A modification of this method of moulding consists in mounting the worm or
screw pattern upon a shaft, which may be fixed or movable in bearings supported
by removeable brackets attached to the ends of the moulding box. Fig. 10 shows
an arrangement of moulding boxes with two end brackets mn fixed to the ends of
the bottom box into which a shaft o is placed and held longitudinally in its position
by collars. or set hoops or equivalent means. The pattern for the worm or screw is
bored out for the shaft to pass through and is loose on the same. The bottom box
may have a semicircular mould formed in it in the manner hereinbefore described
before the shaft o with the pattern a is placed into position, or the bottom box may
be rammed up only to about the level of the underside of the pattern. The shaft o
with pattern is then placed in the box and temporarily fixed so as to prevent them
from turning, and the sand rammed up round the pattern a. After this the fixings
of the shaft o or pattern a are loosened and the pattern screwed forward, by any
suitable means, for instance by a tommy inserted into holes a² in the boss of the
pattern, or by rotating the shaft o, the pattern being connected in this case to the shaft
by a sliding key fitting a groove in the shaft or a long feather on the shaft and a
groove in the pattern. When a semicircular mould is first made, a short cylindrical
pattern at the front end of the pattern a similar to pattern hereinbefore referred
to but shorter is preferably used, such core pattern being wedged against the top
box bars to prevent the worm pattern from shifting and the shaft o from bending
while the ramming up of the sand proceeds successively in the manner hereinbefore
described.
Instead of the arrangement described with reference to Fig. 10, the pattern of
the worm or screw may be fixed upon a shaft p, as shown by Fig. 11, and the
shaft arranged so that it can revolve and slide in bearings 's attached to the
bottom box or if preferred in independent bearings or pedestals between which
the moulding box is placed. The bearings is fitted with a bush t so that the bush
can revolve but not move endways, and the bush is fitted with a key sliding in a
long groove in the shaft p or vice versa and rotated when required by means of a
ratchet brace u or other suitable gearing by hand or power. The moulding
proceeds in a similar manner as hereinbefore described with reference to Fig. 10
and previous figures the pattern a being drawn forward when required by turning
the shaft p which will slide through or along the bearings as it is carried forward
by the worm pattern.
By these methods of successively screwing forward and moulding a convenient
short length of the pattern, it will be understood that worms or archimedean screws
of any desired length as aforesaid and of any required diameter suitable for
conveyors elevators or other such like purposes can be moulded and cast, with
blades of uniform thickness throughout, or of varying thickness, and with the
radii of said blades or the generatrix of the helical surface either at a right
angle to or inclined to the axis, as shown by Fig. 12 partly in section and
partly in outside view, or curved to the axis. The inclined or curved form
of blade, which has hitherto not been made of cast metal, in consequence of
the difficulty of moulding the same, possesses great advantages, making the worm
considerably stiffer and capable of supporting greater strains both in the
longitudinal and transverse direction, and bringing the material to be conveyed or
elevated towards the centre, thereby relieving the surrounding troughs or tubes
from pressure and reducing the friction in or on said troughs or tubes.
The central shafts or parts of the said worms may be made solid or hollow, a
core being in the latter case inserted into the mould and worins or screws may also
be cast by my method of any desired length or diameter as aforesaid with a lielical
blade only and without a central shaft, the turn of the helical blade or screw
forming its own support.
An important part of all my before described methods of moulding and casting
is that instead of parting the box or sand in the usual way, the top box is, as is

page_text: above stated, not removed or taken off during any part of the process of moulding
or casting, until the casting is completely set and then for the purpose only of
removing the casting, and thus the casting is smooth and without seams or scars
from the imperfect joining of the parts of the pattern and of the boxes, so that all
subsequent filing or trimming of the casting is rendered unnecessary.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
Firstly. The method of preparing the moulds for casting metal worms or
archimedean screws (with broad face blades) for conveyors and elevators and
other like purposes in long lengths as aforesaid and of any required diameters
suitable for such purposes by means of a short pattern traversed and moved along
the moulding box substantially as hereinbefore described with reference to and
illustrated by Figures 1 to 9 of the drawings.
Secondly. The method of preparing the moulds for casting metal worms or
archimedean screws with broad face blades for conveyors and elevators and for
other like purposes in long lengths as aforesaid and of any required diameter
suitable for such purposes by means of a short sliding pattern mounted on a shaft
that is held in its longitudinal position in bearings substantially as described with
reference to and illustrated by Fig. 10 of the drawings.
Thirdly. The method of preparing the moulds for casting metal worms or archi-
medean screws with broad face blades for conveyors and elevators and for other like
purposes in long lengths as aforesaid and of any required diameter as aforesaid by
means of a short pattern fixed on a sliding shaft substantially as hereinbefore
described and illustrated by Figure 11 of the drawings.
Fourthly. The manufacture or formation of cast metal worms or archimedean
screws for conveyors and elevators and for other like purposes with blades the
radii or generatrixes of which are inclined or curved to the axis, substantially as
hereinbefore described and set forth.
Dated the 20th day of Decembar 1801
R. J. URQUHART,
57, Barton Arcado, Manchester, Consulting Engineer and Patent Agent.