U.S. patent number 3,877,860 [Application Number 05/069,300] was granted by the patent office on 1975-04-15 for extrusion machine for making articles of cement-like material.
This patent grant is currently assigned to Dyform Concrete Prestressed Ltd.. Invention is credited to George Putti.
United States Patent |
3,877,860 |
Putti |
April 15, 1975 |
EXTRUSION MACHINE FOR MAKING ARTICLES OF CEMENT-LIKE MATERIAL
Abstract
An extrusion machine for continuously making articles, such as
concrete slabs, by forcing the article-forming material through a
mold, said machine being moved forwardly by reaction as the
material is forced against the portion of the article already
formed. The material is moved under pressure by one or more spiral
conveyors through the mold, and a forming element of any
predetermined cross-sectional shape is substantially aligned with
the down-stream end of each spiral conveyor and is mounted so as
not to rotate with the latter. It is perferable to provide a
vibrator in each forming element.
Inventors: |
Putti; George (North Vancouver,
British Columbia, CA) |
Assignee: |
Dyform Concrete Prestressed
Ltd. (Vancouver, British Columbia, CA)
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Family
ID: |
27160694 |
Appl.
No.: |
05/069,300 |
Filed: |
September 3, 1970 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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882039 |
Dec 4, 1969 |
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Foreign Application Priority Data
Current U.S.
Class: |
425/380; 425/432;
425/64 |
Current CPC
Class: |
B28B
1/084 (20130101); B28B 3/228 (20130101) |
Current International
Class: |
B28B
1/08 (20060101); B28b 021/14 () |
Field of
Search: |
;25/41J,41R,41G,14,32,35,11 ;18/12SE,12SM
;425/461,427,432,456,376,380 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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623,476 |
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Jul 1961 |
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CA |
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208,282 |
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Mar 1960 |
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DT |
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946,345 |
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Jan 1964 |
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GB |
|
Primary Examiner: Annear; R. Spencer
Attorney, Agent or Firm: Fetherstonhaugh and Company
Parent Case Text
This application is a division of co-pending application Ser. No.
882,039 filed Dec. 4, 1969 now abandoned.
Claims
I claim:
1. In an extrusion machine including a mold for making elongated
articles of concrete-like moldable material by forcing the material
through said mold, said machine including means for feeding said
moldable material to said mold, said machine being moved forwardly
by reaction as the material is forced against the molded portion of
the article, said machine including means for guiding the forward
motion of said machine along a path for forming the molded material
as an elongate body in said path, the improvement which comprises:
a rotatable spiral conveyor in and extending longitudinally of the
mold for moving the material under pressure through the mold and
against material that has set into the cross-sectional shape
dictated by the cross-sectional shape of the mold, said conveyor
including a spiral flight along its length and a forming element of
non-circular cross-sectional shape immediately following the
down-stream end of the spiral conveyor at the downstream end of
said spiral flight and mounted so as not to be rotated by the
conveyor, means for controlling the rotation of said forming
element relative to the rotation of said conveyor, said conveyor
moving the material under pressure over the forming element whereby
said element forms a core of said predetermined cross-sectional
shape in the article as it is being formed.
2. A machine as claimed in claim 1 in which said forming element is
substantially aligned with said spiral conveyor.
3. A machine as claimed in claim 1 in which said spiral conveyor
comprises a core shaft with a spiral flight wound therearound.
4. A machine as claimed in claim 3 in which the flights of the
conveyor at least towards the down-stream end thereof have radial
faces lying substantially normal to the axis of the core shaft and
facing towards said down-stream end.
5. A machine as claimed in claim 4 in which the upstream faces of
said flights are inclined relative to a radius of the core
shaft.
6. A machine as claimed in claim 3 in which said core shaft has a
constant diameter throughout the length thereof.
7. A machine as claimed in claim 3 in which said core shaft
increases in diameter towards the down-stream end thereof.
8. A machine as claimed in claim 7 in which the flights of the
conveyor progressively increase in diameter towards the downstream
end of the conveyor over that portion of the core shaft of
increasing diameter.
9. A machine as claimed in claim 8 in which the upstream end of the
core forming element diverges towards the downstream end of the
core shaft and down to the size and cross-sectional shape of said
downstream end.
10. A machine as claimed in claim 7 in which the flights of the
conveyor at least towards the downstream end thereof have radial
faces lying substantially normal the axis of the core shaft and
facing towards said down-stream end.
11. A machine as claimed in claim 7 in which the upstream end of
the core forming element diverges towards the downstream end of the
core shaft and to the cross-sectional shape of said downstream
end.
12. A machine as claimed in claim 3 in which said core shaft is
hollow, and including a supporting shaft extending through and
beyond the down-stream end of the spiral conveyor, said forming
element being mounted on and carried by said supporting shaft.
13. A machine as claimed in claim 1 including means for removably
mounting said forming element in position relative to the spiiral
conveyor.
14. A machine as claimed in claim 12 including means for removably
mounting said forming element in position relative to the spiral
conveyor.
15. A machine as claimed in claim 1 including a vibrator mounted
within said forming element.
16. A machine as claimed in claim 12 including a vibrator mounted
within said forming element.
17. A machine as claimed in claim 1 including means connected to
the forming element to rotate said element independently of the
spiral conveyor.
18. A machine as claimed in claim 1 in which said forming element
is in a plurality of interconnected sections.
19. A machine as claimed in claim 18 in which said forming element
sections are detachably connected to each other.
20. A machine as claimed in claim 1 in which said forming element
is in a plurality of interconnected sections and including a
vibrator in the downstream section next to the end of the spiral
conveyor.
21. A machine as claimed in claim 20 including vibration dampener
means forming the connection between forming element section with
the vibrator therein and the section next thereto.
22. A machine as claimed in claim 1 including a frame having side
members adapted to co-operate with a base to create a forming space
therebetween, said mold being positioned in and extending
longitudinally of said forming space and said base being the bottom
wall of the mold, said spiral conveyor being positioned in the
forming spaced and extending into the mold.
23. A machine as claimed in claim 22 in which said mold includes a
substantially horizontal top plate and substantially vertical
spaced side plates, and including means for changing the angles of
said top and side plates relative to the longitudinal axis of the
mold.
Description
This invention relates to extrusion machines for making articles,
such as slabs, panels, beams, and the like from suitable moldable
material such a concrete. The moldable material used is a
relatively stiff mix and rapidly sets to a relatively solid state.
For the sake of convenience, the invention will be described herein
relative to making cored slabs of concrete.
There are many machines in use for making by extrusion concrete
slabs and other concrete articles. An example of the prior art
machines is illustrated and described in U.S. Pat. No. 3,159,897,
dated Dec. 8, 1964. This patent discloses a machine having a
plurality of spiral conveyors or augers each with a spiral flight
fixed to the core shaft thereof. Each auger has a trowelling
mandrel secured to the downstream end thereof so that it rotates
with the auger. A vibrator is mounted on the machine outside the
molding area thereof so that the entire machine is vibrated, and
the vibrations are not where they should be for the best results,
and they are also applied to the part of the finished product
within the machine. As each trowelling unit is fixed to an auger
and rotates with it, it is only possible to form cores in the
concrete slabs of circular cross-section and no other
cross-sectional shape.
An extrusion machine in accordance with the present invention
includes at least one spiral conveyor in and extending
longitudinally of the mold of the machine for moving the concrete
under press longitudinally thereof. A forming element of any
predetermined cross-sectional shape is aligned or substantially
aligned with the down-stream end of the spiral conveyor and is
mounted so as not to rotate with the latter. As a result of this,
the forming element can have any desired cross-sectional shape in
order to produce cores in the finished product of corresponding
cross-sectional shape. The mounting of the forming element makes it
possible to rotate the forming element in the same direction as or
counter to the direction of rotation of the spiral conveyor, and at
the same or a different speed. If it is desired to make a slab with
cores of a different cross-sectional size or shape, it is only
necessary to replace the forming element.
Additionally, should it be required to form solid slabs this can be
achieved simply by removing the core forming element which of
course is not possible with existing machines in which the spiral
conveyor is formed integrally with the core forming element.
It is preferable to provide a vibrator within the forming element
so that the vibrations are imparted to the concrete at the time the
latter is being pressed against the formed part of the slab. This
vibrator can be operated with less power than the vibrator of the
prior art because it does not have to shake or vibrate the entire
machine.
The forming element can be made long enough to form or polish the
inner surface of each core after the slab has been formed but while
it is still within the mold, or it can include one or more
finishing sections or elements fixedly or removably secured to the
downstream end of the main forming element, and it is preferable to
provide vibration dampeners between the forming element sections so
that the vibrations within the forming element are not transferred
to the finishing elements or sections and therefore are not
transferred to the finished portion of the slab.
An extrusion machine according to the present invention comprises
means for feeding concrete to a mold, a rotatable spiral conveyor
in and extending longitudinally of the mold in the machine for
moving said concrete under pressure through the mold and against
the concrete that has set into the cross-sectional shape dictated
by the cross-sectional shape of the mold, and a forming element of
any predetermined cross-sectional shape substantially aligned with
the down-stream end of the spiral conveyor and mounted so as not to
rotate with the latter. The conveyor moves the material under
pressure over the forming element so that said element forms a core
of said predetermined cross-sectional shape in the article as it is
being formed. The spiral conveyor has a spiral flight wound around
a core shaft, said flight preferably being fixed to or formed with
the shaft. Although not necessary for some purposes, it is
preferable to provide a vibrator within the forming element so as
to subject the concrete to high frequency vibrations at the time it
is being subjected to the maximum amount of pressure and is being
pressed against the portion of the slab already formed. In
addition, it is preferable to provide one or more finishing
elements or sections secured to the downstream end of the forming
element through vibration dampeners. These finishing elements have
a cross-sectional shape and size and the same as that of the
forming element.
The conveyor preferably has those flights closer to the core
forming element of slightly greater diameter than the ones more
remote from that element although the core shaft is conventionally
of larger diameter in that region. In this way the composition of
the concrete into the mold region is increased. To further increase
the compression the leading face of the flights in the region of
the mold may be radial to the core shaft i.e. they may be sectional
as opposed to the normal helicoidal flights. In this way the
tendency for the concrete to move up and over those flights is
reduced.
Additionally the edges of the core forming element adjacent to the
conveyor may be chamfered or relieved so that the element tapers
from the desired final cross-section to a lesser cross-section
adjacent the conveyor in this way to allow the concrete to be
packed smoothly around the element.
Additionally or alternatively the pitch of the flights may be
progressively decreased towards the mold or downstream end of the
conveyor to such an arrangement as is possible to use a parallel
sided core shaft.
Examples of machines in accordance with this invention are
illustrated in the accompanying drawings, in which
FIG. 1 is a side elevation of this extrusion machine with the near
side broken away to show a spiral conveyor and its associated
forming element,
FIG. 2 is a plan view of the maching illustrated in FIG. 1,
FIG. 3 is a horizontal section taken substantially on the line 3--3
of FIG. 1, showing two spiral conveyors in plan,
FIG. 4 is an enlarged vertical longitudinal section taken
substantially on the line 4--4 of FIG. 3 showing one of the spiral
conveyors and part of the forming element thereof in section,
FIG. 5 is a cross-section take on the line 5--5 of FIG. 3,
FIG. 6 is an elevation of the downstream end of the machine,
FIG. 7 is a longitudinal section through an alternative form of
spiral conveyor,
FIGS. 8, 9, and 10 are reduced end views of slabs formed by this
machine and illustrating cores of three different cross-sectional
shapes by way of example, and
FIG. 11 is an enlarged longitudinal section through the outer end
of a spiral conveyor similar to but a little different than the
conveyor of FIG. 4.
Referring to the drawings, 10 is an extrusion machine in accordance
with this invention which is adapted to move over any suitable base
in order to form articles of moldable material, such as concrete
slabs. The articles may be formed on the ground or any other
suitable base which actually constitutes the bottom surface of the
mold of the machine. In this example, the machine moves along a
base 12 having vertical sides 13 and 14 which form rails for the
machine, said base being supported in any suitable manner, such as
by channels 15 and 16 upon which sides 13 and 14 rest.
Machine 10 is made up of a main frame 19 consisting of side members
20 and 21 interconnected by cross members 22 and 23 at opposite
ends thereof. A supporting frame 26 is mounted on side members 20
and 21 between the ends thereof and extends across the machine.
Frame 26 can be adjusted up and down relative to main frame 19 by
bolts 27. Frame 19 is provided with wheels 28 that rise on rails 13
and 14, and as it is necessary to prevent the down-stream end 30 of
the machine from rising during operation of the apparatus, brackets
32 extend downwardly from frame 19, and carry wheels 33 which
engage the lower surfaces of sides 13 and 14, see FIG. 6.
If machine 10 is used to form a relatively narrow slab or beam with
a single core therein, only one spiral conveyor 37 is mounted
therein. However, there are usually several of these conveyors in
the machine, two conveyors being shown in the illustrated machine.
As the spiral conveyors and the forming elements associated with
them are the same as each other, only one will now be described in
detail.
The spiral conveyor 37 is mounted at one end in suitable bearings
carried by supporting frame 26 between side member 20 and 21. This
conveyor is made up of a flight 40 secured to or formed with a
hollow core shaft 41. In this example, shaft 41 has a straight
section 44 extending throughout part of the length of the conveyor,
and a diverging section 45 extending throughout the remainder of
the conveyor at the downstream end 46 thereof. Flight 40 may have a
constant outer diameter as illustrated at 49 in FIGS. 1 and 4.
Alternatively and as described with reference to FIG. 11 the outer
diameter of the flight may be greater at the down-stream end of the
conveyor.
Each conveyor 37 is rotated in any suitable manner, and in this
example, one conveyor is driven by a chain and sprocket arrangement
54 which is driven by a suitable source of power, such as an
electric motor 55 mounted on frame 26. While the other conveyor can
be driven by the drive 54, it is preferable to rotate the latter
conveyor in the opposite direction by gears 56 and chain and
sprocket arrangement 57.
A forming element 62 is located at the down-stream end 46 of
conveyor 37, and is mounted so as not to be rotated by the
conveyor. In this example, forming element 62 is mounted on the end
of a hollow shaft 63 which is carried at its opposite end by
supporting frame 26. Shaft 63 can be fixedly mounted or, as shown,
it can be mounted for rotation, in which case it is rotated by a
chain and sprocket arrangement 64 which is driven by a suitable
source of power, such as an electric motor 65. Forming element 62
is fixedly or removably mounted on the end of shaft 63 beyond the
outer end of conveyor 37, and in this example, said forming element
is mounted on the end of shaft 63 by bolts 66.
Forming element 62 can be of any desirable cross-section if shaft
63 is not rotated, such as oval, square, triangular, and the like
or if it is desired to form slabs without a core the elemenet 62
can be removed. However, if shaft 63 is rotated, the forming
element will form a core of circular cross-section, in which case,
the element itself can be circular in section. The forming element
can be no larger in cross-section than the spiral conveyor, as
shown or it can be cross-sectionally larger.
It is preferable to provide a vibrator 68 within forming element
62. Any suitable vibrator may be used for this purpose, such as an
eccentric vibrator, as shown. In this example, vibrator 68 consists
of a body 70 mounted on a shaft 71 which is offset a little from
the longitudinal central axis of the body. Shaft 71 is journalled
in bearings 72 which are carried by a housing 73 supported within
the forming element 62 and having perforations 74 therein. A drive
shaft 75 is connected at one end to shaft 71, and extends
longitudinally through shaft 63 to a suitable source of power, such
as a small electric motor 76 carried by support 26 beyond the end
of said shaft 63, see FIG. 1. The bearings 72 are lubricated by oil
79 in forming element 62 which forms a housing or reservoir
therefor. The level of this oil is normally kept above the bottom
of vibrator body 70 so that the latter splashes the oil to
lubricate the bearings. In addition, during operation of vibrator
68, the eccentric body 70 thereof slides over the inner surface of
housing 73 and creates a suction through perforations 74 to draw
oil therethrough even when the level of the oil is low. In effect
there always is a mist of oil within the forming element to keep
bearings 72 lubricated.
When the forming element is removed to produce slabs with no core
it is apparent that if vibration is required it will be necessary
to apply it externally of the body. Such arrangements are well
known per se and as such are not described in detail herein.
Obviously even with a core forming element external vibration may
be applied to the mold as an alternative to or additionally to the
internal vibration system illustrated.
Forming unit 62 may be relatiely long, or it may be formed in two
or more interconnected sections, as shown. The forming element in
this case consists of a main section 82 which is connected to and
supported by the outer end of shaft 63, and to additional sections
83 and 84. The two additional sections are the same size and shape
in cross-section as main section 82, and section 83 is connected by
a dampener 86 to section 82, while section 84 is connected to
section 83 by a dampener 87. Main section 82 acts as a forming
element, while sections 83 and 84 act as finishing elements. Any
suitable type of dampener may be used. An example is illustrated in
FIG. 4. Each of the dampeners is made up of a resilient block 88
located between the connected sections, and bolts 89 extending from
said sections into the block to hold these element together.
A hopper 90 is mounted on frame 19 above the inner end of spiral
conveyor 37. This hopper directs previously-mixed concrete of the
desired consistency down into the area between the sides of frame
19 at the inner end of the spiral conveyor or conveyors. There are
usually a plurality of these conveyors in apparatus of this type.
The width of the slab to be produced is determined by side plates
on edge mounted on opposite sides of the spiral conveyors. There
may be one or a plurality of plates at each side. In this example,
there are two substantially aligned plates 92 and 93 on one side of
the machine, and substantially aligned plates 94 and 95 at the
opposite side thereof. Plates 92, 93, 94 and 95 are mounted for
adjustment on frame side members 21 and 22 by means of bolts 97,
98, 99 and 100, respectively. The plates can be moved towards and
away from the side members by these bolts. Plates 92 and 94 are
usually inclined slightly towards each other in the direction of
the down-stream or discharge end of the machine, while plates 92
and 93 are usually inclined towards each other in the same
direction but to a lesser extent. The distance between the
discharge ends of plates 93 and 95, indicated at 102, determines
the width of the finished product.
A support 105 extends across the machine above the conveyors and
forming elements thereof and are mounted on side members 20 and 21
and adjustable vertically thereto by shims and bolts 106. One or
more horizontal top plates are suspended from support 105 above
said conveyors and forming elements. In this example, top plates
108 and 109 are adjustably suspended by bolts 111 and 112
respectively. Side plates 92, 93, 94 and 95 and top plates 108 and
109 for the sides and top of a mold 115 for forming the concrete
articles or slabs, the surface on which machine 10 operates forming
the bottom of this mold, and in this example, base 12 serves this
purpose.
During operation, pre-mixed concrete of the desired consistency is
fed by the hopper 90 into the space immediately therebelow. This
concrete fills the mold 115, engulfing the spiral conveyors and the
associated forming elements. As the conveyors rotate, they tend to
move the concrete towards the discharge end of the machine, but as
this movement is resisted and stopped by the portion of the slab
already formed, the concrete is subjected to pressure as it moves
through the mold, and the machine moves in the opposite direction.
The pressure in the concrete depends upon the force necessary to
move the mass of the machine. The pressure can be regulated by
changing the angles of side plates 92, 93, 94 and 95, and/or of top
plates 108 and 109. The concrete is also moved around the sections
82, 83 and 84 of the forming elements as it travels towards the
discharge end of the machine.
As the concrete is moved around the forming elements these form
cores in the finished product of the same cross-sectional shape and
dimensions as the forming elements. The vibrators operate within
the forming elements, and this subjects the concrete to high
frequency vibrations as it is being compacted into the finished
article. This improves the compaction, and if prestressing strands
or cables extend through the machine so as to be incorporated into
the finished slab, the vibration within the concrete mass assures a
very strong bond between the strands or cables and the concrete.
The compaction is so good as a result of the vibrators within the
concrete that the finished slab or article is immediately
self-supporting.
The finishing sections 83 and 84 support the concrete within the
cores formed therein while the concrete is still being subjected to
external pressure. They also help to finish or smooth the surfaces
of the cores within the slabs. If the complete forming elements is
circular in cross-section, it can be rotated at the same or
different speed from the speed of rotation of the spiral conveyors,
and in the same direction as or opposite to the direction of
rotation of said conveyors. This makes it possible to rotate to
conveyors and the forming elements at the best speeds for their
respective purposes. The rotating finishing sections of the forming
elements polish the surfaces of the cores. Dampeners 86 and 87
prevent the vibrations from the vibrators from being transferred to
finishing sections 83 and 84, and, therefore, to the finished
portion of the slab.
FIG. 7 illustrates an alternative form of conveyor 37a which has a
tubular core shaft 120 which does not have a diverging outer
section similar to section 45 on shaft 41. Conveyor 37a includes a
spiral flight 122 wound around and secured to shaft 120. Conveyor
shaft 120 is rotated in the same manner as conveyor shaft 41
described above.
In the example of FIG. 7, forming element 62 is mounted on the end
of a tubular shaft 125 which may be fixedly mounted in the machine,
or it may be rotated by the same drive means as shaft 63 of
conveyor 37. The remaining elements of conveyor 37a are the same as
those of conveyor 37, aand the two conveyors operate in the same
manner.
Machine 10 is such that suitablle reinforcing rods may extend
therethrough so that the rods are incorporated in the concrete
slabs as the latter is formed. Similarly, prestressing strands or
cables can extend through the machine, in which case these are
incorporated in the slab. By having the vibrators within the
forming elements, the high frequency vibrations are applied to the
concrete exactly where they are reqquired and where they will do
the most good. These vibrations also cause the concrete to bond
very firmly to the prestressing strands or cables.
The mounting of the forming elements so that they can remain
stationary while the spiral conveyors rotate makes it possible to
form cores of any desired cross-sectional shape within the concrete
slab. For example, these forming elements may be cylindrical,
square, oval or any other suitable shape in section. FIGS. 8, 9 and
10 have been included to illustrate finished slabs 130, 131 and 132
having therein cores 134, 135 and 136 respectively of different
cross-sectional shapes. These are examples of different shapes that
can be produced. If the forming elements are cylindrical, they can
be rotated in the same direction as or counter to the rotation of
the conveyors, and they can be rotated at the same or different
speeds. Thus, the forming elements can be rotated as desired in
order to produce well honed cores in the slabs.
The provision of several finishing sections in the forming elements
makes it possible to support the slab internally for a longer
period after the slab has been formed around the main forming
elements than would normally be possible. The dampeners between the
forming element sections prevent the high frequency vibrations from
being transferred to the finished slab so that the latter is
dimensionally stable regardless of the fact that it has just been
formed and has just emerged from the forming mold.
Another advantage of the present machine results from the fact that
the forming elements can be easily and quickly removed from the
machine without interfering with the spiral conveyors which it is
desired to make solid concrete slabs. The side plates 92, 93, 94
and 95 can easily be shifted laterally in order to produce slabs of
different widths, while top plates 108 and 109 can be adjusted
vertically. This machine can be used to produce slabs of different
thicknesses and with cores of the same or different sizes.
Transverse frame 105 can be adjusted up and down on frame 19 when
it is desired to change the thickness of the slab being formed.
Frame 26 will also be adjusted up and down to centralize the cores
relative to the top and bottom of the slab. If the core size has to
be changed, it is not necessary to replace the spiral conveyors but
only to replace their associated forming elements. Two layers of
cores may be formed in the slab by providing two layers of
conveyors and forming elements within the mold of the machine.
In the conveyor illustrated in FIG. 11 the core shaft 140 has
flights 141 fixed to it by welding or bolting or by forming them
integrally.
The shaft 140 has a diverging section 142 and the flights 141 on
that section are of progressively larger diameter towards the core
forming element so that their compressure effect on the concrete at
that region is increased over the effect of flights which is not so
increased. Additionally, while the flights on the parallel sides
section of the core shaft are of conventional helicoidal form those
on the diverging section are of sectional form having those faaces
143 towards the core forming element (i.e. the downstream side)
radial and lying substantially normal to the axis of shaft 140 and
those faces 144 remote from that element sloped.
This feature tends to resist the movement of the concrete up and
over the faces 143 and thus further increase the compressure effect
of the conveyor. To "lead" the concrete into the mold the end of
the core forming element adjacent to the conveyor is chamfered or
tapered as at 145.
Desirably the pitch of the flights becomes less towards the
downstream end of the conveyor, as shown, and this characteristic
may be combined with the features prescribed above or may replace
them.
* * * * *