Note: Descriptions are shown in the official language in which they were submitted.
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The present in~ention relates to a method and
apparatus for manufacturing reinforced concrete elements,
namely elongated construction elements, such as beams, girders,
joists, lintels, posts, piles or the like, of prestressed
concrete.
:- Generally speaking, an aim of the invention is to
provide a method by which concrete elements, in particular
elongated construction elements such as beams or joists of
prestressed concrete, can be manufactured under optimum
industrial conditions.
According to one aspect of this invention there is
provided a method of manufacturing a series of elongate
¦ concrete construction elements by manufacturing successive
: portions of said elements comprising: i- molding a portion
of each element by pouring concrete into a molding unit
comprising, located on a molding area, a front wall and a t
retractable rear wall arranged across the molding area and
;. a series of mutually parallel formers extending along the
,. .
~:~ molding area and constituting lateral walls between the front
. 20 and the rear walls to form a series of molds, said walls being
.. adapted to move on the molding area; ii- vibrating the poured
concrete; iii- after the concrete has sufficiently hardened,
.. retracting the rear wall of the molding unit; iv- displacing
~ with a translatory movement the lateral walls along the molding
.1 area to leave behind molded portions of the elements while
maintaining stationary the front wall; v- displacing with a
~` translatory movement the front wall along the molding area
up to the successive portion; vi- molding a successive portion
~:. of each element by pouring concrete into the space provided
.,~` 30 between the front wall, the lateral walls, the front ends of
;
the already cast portions and tne molding area; vii- vibrating
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the poured concrete; ~iii- molding successive portions of
each element in the same manner until a desired length of
element has been obtained; and ix- eventually heating the
elements to harden the concrete.
According to another aspect of this invention there
ie provided apparatus for manufacturing a series of elongate
prestressed concrete construction elements comprising: i) a
manufacturing bed designed to absorb the compressive forces
developed during the manufacture of the elements, ii) an
elongate molding area above the bed; iii) means for heating
the molding area; iv) a series of molds comprising a plurality
~ of lateral walls fixed on a first movable assembly mounted for
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translatory movement along the bed, said assembly having at
its rear end - relative to the direction of displacement
along the bed during manufacture - a retractable flap adapted
r~' to form the rear wall of the molds, and front walls constituted
by the ends of arms of a second movable assembly, said arms
being located between the lateral walls; v) means with
- vibrating members for feeding and distributing concrete into
the series of molds; vi) means for displacing the movable
assemblies independently from each other in a direction parallel
.....
to the lateral walls, so that the second movable assembly
remains stationary during the forward displacement of the
~- first movable assembly, the retractable flap having been
raised before this forward displacement and so that after
, displacement of the first movable assembly, said second
`` movable assembly can be displaced forwardly.
Preferably, the apparatus comprises means for
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automatically vibrating additional reinforcements, sometimes
known as stirrups or binders, crosswise into the freshly
poured concrete in the moulds.
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Preferably, means are also provided which, after
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pouring the concrete, cover the entire area on which partially
hardened concrete elements are still supported with a large
size thermal insulating tarpaulin which is automatically
rolled and unrolled by means of a carriage displaceable along
rails.
The invention will be fully understood by the
: description of embodiments thereof which follows, by way of
example, with reference to the accompanying drawings, in which:
Figures la, lb and lc are plan views in schematic
10 forms of apparatus according to the invention in the various t
positions of the casting procedure;
Figure 2 is a perspective view in simplified form
: of a portion of apparatus according to one embodiment of
. this invention;
Figure 3 is a partial longitudinal section of the
body of a bed of the plant according to the invention;
Figure 4 is a view similar to that of Figure 2, but
for another alternative embodiment;
Figure S (located with Figures 8 and 9) is a longi-
20 tudinal sectional view of an end of the bed;
;; Figure 6 is a partlal top view of the manufacturing
bed for still another embodiment;
,5,
.. Figure 7 is a sectional view on line 7-7 in Figure 6;
Figure 8 is a sectional view on line 8-8 in Figure 6;
;. Figure 9 is a partial longitudinal sectional view of
~: an end of the bed of an alternative embodiment;
Figure 10 is a bottom view of a moulding area for
_another alternative embodiment;
: Figure 11 is a sectional view on line 11-11 in Figure
10, but on an enlarged scale;
Figure 12 is a sectional view on line 12-12 in Figure
~` 10, but on an enlarged scale;
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:: Figure 13 is a schematic view of the heating circuit
for the bed; :~
Figure 14 is a view similar to that of Figure 13,
: but for an alternative embodiment;
. .
Figure 15 is a schematic view in section of seal means
for a heating pipe;
, Figure 16 is a schematic view illustrating heating
. means for the bed according to another embodiment;
Figure 17 is a sectional view along line 17-17 of
. 10 Figure 16, but on an enlarged scale;
~, Figure 18 is a schematic view in section of still
another heating system;
-~ Figure 19 is an elevational view of an embodiment of
l means for tensioning prestressing reinforcements;
;~. Figure 20 is a view similar to that of Figure 19,
~';. but for another embodiment;
Figure 21 is an elevation view of a part of the means
. shown in Figure 20 viewed in the direction of arrow F in
Figure 20;
Figure 22 is a plan view of a part of the moulding
; unit of a plant according to the invention;
Figure 23 is a sectional view taken along line 23-23
in Figure 22;
Figure 24 (located after Figure 26) is a sectional
~! view of a component part of the moulding unit;
i., Figure 25 (located after Figure 26) is a perspective
~ view of the part of the moulding unit illustrated in Figures
~,
22 and 23;
.; Figures 26a and 26b are sectional views of mold
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'i 30 elements;
i Figure 27 is a view of a winch device for a plant;
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Figure 28 shows brake means for a movable assembly of
the molding unit;
Figure 29 is a detail view of a part of the moulding
unit;
Figure 30 is a top view of a part of the moulding unit;
Figure 31 is an elevation view of part of the moulding
, unit;
Figure 32 is a side view of part of the moulding unit;
Figure 33 is a view similar to that of Figure 32, but
for an alternative embodiment;
Figure 34a is a schematic view of another embodiment
of the drive means for the moulding unit;
. Figure 34b is a view in section taken on line 6-6 in
Figure 34a;
Figure 34c is a sectional view taken on line c-c in
'Figure 34a;
'Figure 35 is an elevation view of a bucket for pouring
the concrete;
Figure 36 is a sectional view taken on line 36-36 in
, . ~
.,20 Figure 35;
Figure 37 is a top view of the bucket shown in
,Figure 35;
Figures 38 and 39 are schematic views similar to that
of Figure 36 for illustrating the operation of the bucket for
.. ,, pouring concrete;
Figure 40 is an elevation view of a device for
positioning transverse reinforcements;
_ Figure 41 is a side view of the device for positioning
. transverse reinforcements;
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Figure 42 is a schematic view of apparatus for
positioning the thermal insulating tarpaulin;
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Figure 43 is a plan view of the overall plant with
its superstructure; and
Figure 44 is a sectional view taken on the line 44-44
in Figure 43, but on an enlarged scale.
In the preferred embodiments of the invention as
described below, elongated prestressed concrete elements
are formed by casting first portions of the elements in a
plurality of molds, displacing the molds along the already
cast portions up to a second molding position where second
portions of the elements are cast and, if necessary, with-
drawn in a similar manner so that subsequent portions can
be cast until elements of the desired length are obtained.
This principle is illustrated schematically in
Figures la to lc of the drawings. The lateral walls of tne
- molds are constituted by elements 126 fixed on a movable
assembly. A retractable flap 160 on the movable assembly
forms a rear wall for the molds with respect to the displace-
ment direction of the movable assembly. The front walls of
the mold are formed by blocks 175 located between the lateral
~ .,
i' 20 walls of the molds and fixed on a second movable assembly
,........................................................................... .
(Fig. la).
When first portions of the elements have been cast
in the molds defined by the lateral walls 126, front walls
175 and rear wall 160, the rear wall is raised. The first
movable assembly is then displaced forwardly while the front
; walls 175 fixed on the second movable assembly are maintained
stationary (Fig. 16). In this manner, the first cast portions
~of elements are rigidly maintained in position during their
withdrawal so that the elements 126 do not damage the
already cast portions.
When the first movable assembly has reached its
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second molding position, the walls 175 of the second mo~able
assembly are displaced forwardly so that second portions of
the elements can be cast (Fig. lc).
Successive portions of each element are thus molded
until a desired element has been obtained.
Suitable apparatus of this type is shown in Fig.
2 where like reference numerals indicate corresponding parts.
The apparatus and method are described in more detail
below with reference to Figs. 3 to 44.
Each of the elements of the preferred apparatus is
described below under the appropriate headlng.
A. The Bed of the plant
The bed of the plant comprises two sunken masses or
piers at the ends of the concrete bed. Depending on the nature
; of the soil, the piers are simple massive bodies or are com-
posed of a block and anchoring means with, if necessary, tie
rods for interconnecting the masses. A ribbed slab or beam
extends between the two masses which support the moulding
area and absorb the compres~ive forces developed by the tension
~; 20 in the prestressing reinforcements of the elements being
manufactured.
When the ground on which the plant is to be located
; is of good quality, one end mass or pier comprising a wall 1
~ ~Figure 3) of reinforced concrete comprising at the upper end
, ...................................................................... .
of its outer surface an embedded metal section 2 bearing the
; means for tensioning the prestressing reinforcements, described
; in detail hereinbelow, which are received in a pit 20
delimited by a wall 21 and a bottom wall 23 with cavities 24
. .
and 24a for receiving a metal part of the means for tensioning
and releasing the tension in the reinforcements transmitting
the reaction forces Q developed by the tension in the prestressed
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reinforcements of the elements to be manufactured.
Perpendicular to the wall 1, the bed comprises a
concrete slab 5 having an end portion 5a, which is thicker
than its central portion 5b, for distributing the compressive
forces, the end portion 5a being connected to the central
~,, .
portion 5b by a zone 5d which is poured and matted after the
portions 5a and 5b of the slab have shrunk.
The slab 5 is separated, as shown at 5c, from the
-- end mass forming the pit so that any eventual sinking of
the pier or end mass under the effect of the alternating
~' forces does not cause the sinking of the wall 1.
The lower surface of the upper part of the slab 5
is provided with thermal insulation 8, the length of which
. .
s may be in the range of sixty meters and the width from two
to three meters, and a recessed portion 4 adapted to receive
heating means for the flat work or moulding area comprising
,. .
metal plates 3 forming the bottom of the moulds into which
the concrete is poured.
In a further embodiment (Figure 4), particularly
~ 20 useful when the heating for the work area is effected with
; expanded steam, two HN type sections 11 and lla act as guiding
means for fixing the movable assemblies against movement on
the rails, the recessed portion 12 having inclined surfaces
,; 12a necessary for draining off the condensate.
:; If necessary, the end masses of the manufacturing bed
forming the pit for receiving the means for tensioning and
~. .
releasing the tension in the prestressing reinforcements are
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~ interconnected by prestressing cables 26 (Figure 5) or by the
: :.
concrete reinforcements passing through a box girder 16.
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Irrespective of the construction of the bed, it is
` poured in several steps in order to avoid cracks caused by
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1~57032
the shrinking of the concrete, sealing zones-are provided,
e.g. ~one 5d, being matted when the major part of the
shrinking has occured.
We are also-concerned with adapting the bed for the
manufacture of construction elements of different lengths, `~
using a bed as shown in Figures 6-8, i.e. in which the slab
5 is replaced by a massive girder 27 of reinforced concrete
prestressed by reinforcements or cables 27b, the upper surface
27a of which being adapted to receive the moulding or work
area, and the girder is broken up at one or more suitable
points along its length with wells 28 and 28a extending over
the entire height thereof (Figure 8). The wells 28 are of
substantially square cross-section and their transverse faces
in the longitudinal direction of the bed have upper and lower
metal fixtures 29 and 29a respectively for supporting the means
for tensioning and releasing the tension in the reinforcements.
In a plant with such a bed, the wells 28 are closed with metal
covers 30 when the entire height of the wells are to be used,
and means for tensioning and releasing the tension in the
reinforcements are installed at each end of the bed.
, Alternatively, however, the means for tensioning and
"' releasing the tension in the prestressing reinforcements of
the elements being manufactured may be provided at only one
end of the bed, if the other is as shown in Figure 9, i.e. a
pier 31 integral with the slab 5 without a seal therebetween,
along which a plate 32 with rectangular anchoring cutouts for
the ends of the prestressing reinforcements, the plate being
anchored in the concrete of the pier or mass 31 by steel
reinforcements such as shown at 33.
B. The Moulding or Work Area
` The moulding area is fixed on the bed and comprises
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very thick metal plates 3, for example ten or more milli-
meters thick, of large dimensions, for example 2 x 6 m,
provided advantageously with stiffening means.
; In an embodiment which employs a heating system in
which steam is expanded in a vapour chamber 43 (Figures 10-12),
the moulding area is supported on the bed by short metal
pillars 42 embedded in the bed, the height of the pillars -
- being adjustable by screwing. I-beams 36, 36a bear against
the pillars welded to the underface of the metal plates 3
which are also supported on the I-beams 11 fixed to the bed.
The chamber 43 which is supplied by tubes 44 carrying steam
for heating is delimited at its upper end by the juxtaposed
metal plates 3 joined together by the flat bars 39a, welded
at 39b to one of the plates and fixed to the adjacent plate
by screws 40 with countersunk heads and by the split pins 45
absorbing the shearing force due to expansion which could not
be taken by the screws 40. As in the first embodiment of the
; moulding or work area, two lateral screws 41 and 41a secure
,~ one of the metal plates to the bed, preferably over a third
;~ 20 of the length thereof.
C. Heating System for the Moulding or Work area
In an embodiment utilising hot water flow through
pipes 37 (Fig. 13) a water chest 46 with partitions 47 is
.......
, located at one end of the bed fixed, relative thereto, under
the moulding area. A hot water feed conduit 48 and an outlet
; conduit 49 extend into the water chest, the water circulation
....
being at a high flow rate with a low temperature gradient
_between its intake and delivery conduits.
~; When the width of the bed is relatively large (Fig. 14),
the water chest 50 provided at one end of the bed is divided
.,.
~ with partitions 51 and 52 into two compartments 53 and 54
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1~57032
which are connected to a forked conduit 55 for feeding the
hot water and a compartment 56 which is connected to a
delivery conduit 57. A blow-off device 58 for blowing out
air pockets may be provided in either embodiment.
- To compensate for the expansion of the pipes 37,
sliding seal means are provided (Figure 15) comprising, on
each pipe 37, an end flange 60 bolted to a sleeve 61 by
another flange 62 and, on the water chest, a short length
63 of pipe connected to a nipple 64 of the water chest by
flanges 65, 65a; the free end of the length 63 of pipe
carries a seal 66, for example of neoprene, clamped between
a flange 67 and a flange 68; the sleeve 61 is machined on
its outer surface and slides inside the seal 66.
When, as shown in Figure 12, the metal plates 3 forming
the moulding or work area are heated with expanded steam, the
steam injection tubes 44 (Figures 16 and 17) are provided
with calibrated orifices 70 capped with deflectors 71 adapted
to ensure an excellent distribution of the heating fluid which
is supplied at the mid-point along the length of the bed from
an equilibrium header 72 connected by a conduit 73 to a boiler
:~ and by conduits 74 to flexible loops to a blow-off device 80
. with an automatic bleeder 81. One or more temperature probes
76 located in the chamber 43 control a valve 77 with a by-pass
78 for manual control by appropriate means.
, . .
Besides the two embodiments of heating systems de-
scribed above, by means of the circulation of hot water through
a group of pipes or by means of expanded steam, other means for
:,
heating the moulding or work area may be provided.
In the embodiment of Figure 18 which employs Joule
effect heating, the resistance heaters 85 are distributed at
appropriate intervals under the plates 3 and coated with a
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special product held by galvanized shells. The plates 3 are
supported on the short pillars, such as 42, and a perfectly
flat bed of dry sand 86 which is provided in the recess in the
upper surface of the bed, a fluid-tight layer 87 being provided
along the surfaces of the recess beneath the bed of sand.
D. Means for Tensioning and Releasing the
Tension in Reinforcement members
In a pit 20 at at least one end of the bed, means
88 for tensioning and releasing the tension in the prestressing
10 reinforcement of the elements being manufactured are housed
< (Figure l9). The ends of the reinforcements which are not
secured to the means 88 are fixed to a stationary anchorage,
such as shown in Figure 9, or fixed to means similar to means
, 88 and located at the other end of the bed or in one of the
pits, such as 28 or 28a, provided along the length of the bed
between the ends thereof.
; The means for tensioning and releasing the tension
in the relnforcement members comprises two parallel arms
pivotably mounted about a horizontal pivot at their lower ends
,
20 under the action of hydraulic jacks. In case of leaking in
the hydraulic control circuit of the jacks, safety means are
provided for preventing displacement of the arms during the
operating phase. Means are associated with the arms for
hooking and holding the ends of the prestressing reinforcements
; against movement.
In a first embodiment (Figure 19), the jacks 19 for
actuating the arms 93 are single-action jacks pivoted at 91a
_on the arms, the piston rods 91c of which are pivoted at 91b
on the metal frame 92 bearing against the wall 1 of the bed,
30 the frame is also used for positioning the means 88 owing to
; the cross members 92a and 92b pivotally connected at 92c.
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llQ~7032
The end of the cross member 92b opposite the pivot point
bears on the wall 21 of the pit 20 by a pressure screw 92d.
The arms 93 which are substantially vertical in the
tensioning position of the reinforcements A are adapted to
pivot in the direction of the arrow F about the pivot pins ;
89 carried at the ends of the cross members 92a received in
the cavity 24 in the bottom of the pit 20 in which a part 90
for positioning means 88 for tensioning and releasing the
- tension in the prestressing reinforcements is located.
For securing to means 88 the ends of the prestressing
reinforcement members, or reinforcements, of the concrete
elements to be manufactured, provision is made for connecting
; to the arms 93 horizontal plates 94 separating by spacing
members 95 and a shim 97, the lower end of the shim resting
on a block 98 on which a rod 96 is fixed parallel to the arms.
~; Pairs of adjacent horizontal plates form between one another
spaces through which pass the prestressing reinforcements A
which are adapted to be tensioned by means of a jack and then
" anchored by means of any appropriate device, for example, jaws
MO.
In an embodiment shown in Figures 20 and 21, the
jacks 111 are double-action jacks and the arms 93 of the
preceding embodiment are replaced by a portal frame 113 whose
`;~ legs are connected by a cross beam 113a with a superposed
plate 113b forming rectangular notches 113c (Figure 21) for
receiving the prestressing reinforcements.
As in the embodiment of Figure 19, a part 110 of the
means for tensioning and releasing the tension in the re-
inforcements is received in a cavity 24 at the bottom 23 of
~` 30 the pit 20, the double-action jacks 111 bearing against the
bed through a massive horizontal girder 112 on which guide
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pulleys 116 for the prestressing r~inforcements are fixed.
The girder 112 is supported on masonry or concrete supports
112a, each jack 111 being pivotally mounted at llla on the
portal frame 113 and at lllb on the girder 112 which bears
against the wall 1 through bearing rollers 114 and 115.
The safety device associated with the means for
tensioning and releasing the tension in the prestressing
reinforcements comprises arms 117 with square threads
pivotally mounted at 117a on the legs of the portal frame
113 and with guide members 118. The arms 117 co-operate with
the nuts 118' which are fixed to the actuating flanges 119
- of a swinging pawl ll9a for controlling the supply of current
to the motor of the hydraulic pump. After tensioning the
prestressing reinforcements of the construction elements to
be manufactured, the nuts 118' are tightened by hand on bearing
parts 120 pivoted at 120a on the girder 112, and during the
relieving of the pressure in the jacks 111, if the nuts 118'
are not previously loosened, the swinging of the pawl ll9a
stops the supply of current to the hydraulic pump thereby
preventing displacement in case of leaking in the hydraulic
circuit during this phase of operation.
E. Moulding Unit
The moulding unit comprises a group of moulds and
means for supplying and distributing the concrete in the
moulds.
El. The Group of Moulds
The bottom of the moulds is formed by the moulding
_area comprising metal plates 3, a first movable assembly 125
(Figures 22 and 23) carries suitable formers 126 for con-
stituting the lateral walls of the moulds and a secondmovable assembly with fingers or projections housed between
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1~571)32 --`
two adjacent former elements, the ends of the second movable
assembly carry blocks (Figures 24 and 25) of section com-
plementary to the elements to be manufactured on the bed,
these blocks form the forward transverse walls of the moulds
into which the concrete is poured.
The elements 126 constituting the lateral walls of
the mould are fixed at their forward ends to a cross member
127 on the movable assembly 125 and at their rear ends to the
cross member 128 on the same movable assembly as shown in
Figure 1.
,, .
` In a first embodiment (Figure 26a) which is
advantageous because it prevents the transmission of the
vibrations for setting the concrete on the moulding area,
bracing members 131a are welded to the metal casing 130 and
pass through openings 131b in the central web. The interior
of the casing 130 is filled with plastic foam material 133, for
example high-der,ity polyurethane foam, which ensures the
desired rigidity of the assembly as well as the joining of
the central web 131 to the casing 130. The portion of the
central web 131 inside the casing is less than the height of
the casing.
In a particularly advantageous embodiment tFigure 26b),
the central web is provided at its lower end rubbing against
the moulding or work area of metal plates 3 with a wear-
resistant pad 135 adapted to be removably secured to the web
` by screws (not shown).
The movable assembly 125 with front wheels 136 and
rear wheels 137 is adapted to be displaced on the rails on
~`; the bed by means of a winch 140 (Figure 27) having a cable
141 secured to the forward cross member 127 or by means of
a motor with reducticn gear mechanism; hydraulic braking
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11057032
means 142 ~Figure 28) with linings 143 and 144 mounted on
the levers 145 and 146 which are pivotally mounted on the
piston-and-cylinder unit 147 is provided for fixing the
movable assembly against movement on the bed during the pouring
of concrete.
For manufacturing prestressed concrete elements of
the same type but with different heights, the wheels 136 and
137 of the movable assembly 125 include height adjusting
means (Figure 29) in which the axle 150 for the wheels 136
and 137 has an eccentric bearing relative to its end journals
`. 152 and 153. The position of the axle 150 is adjusted by
means of a wheel 154 fixed for rotation with the shaft 151
,: with peripheral teeth 155, a rib carried by a frame 157 of
assembly 125 as well as a blocking key 158 are adapted to
. pass between adjacent teeth 155.
~
.: The rear wall of the moulds for pouring concrete
relative to the direction of displacement of the movable
assembly 125 during the manufacture of the elements comprises
a retractable flap or partition 160 for the movable assembly
125 in the immediate vicinity of the rear cross member 128
; (Figures 1, and 30-33) in its lowered position as shown in
solid lines in Figures 32 and 33 (indicated by arrows having
broken lines in Fig. 1) during the pouring of concrete and in
raised position as shown in phantom lines in Figures 32 and
33 (solid lines in Fig. 1) during the removal from the moulds,
i.e. during the movement in the direction of the arrow _
(Figure 22) of the movable assembly 125. A stiffening plate
:: 161 is welded to the rear face of the retractable flap or
partition 160 which also has at its lower end vertical slots
of different heights 162 and 163 (Figure 31) adapted to
~ receive for positioning the prestressing reinforcements A
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which extend from one end of the bed to the other. To
complete the positioning of the reinforcements, the retractable
flap 160 also comprises flat bar projections 164 mounted on
the vertical spindles 165, the number of which corresponds to
the number of elements to be manufactured simultaneously
along the width of the bed and which may pivot when the
cranks 166 connected to each other by a coupling bar 167 are
moved perpendicular to the longitudinal axis of the bed.
During the pouring of concrete, the projections 164 are
perpendicular to the prestressing cables A of the elements
to be manufactured which are thus held captive between the
projections and the slots 162, 163 in the retractable flap
.j, .
while prior to the withdrawal of the moulded elements, the
actuation of the bar 167 causes the spindles to rotate for
bringing the projections 164 parallel to the prestressing
cables, whereas the actuation of a spindle 169 fixed to a
gear wheel controls the raising movement of a gear rack 171
fixed to the retractable flap 160 in slides 172.
As shown, the front ends of the moulds are formed
by blocks 175 (Figures 1 and 25) having sections complementary
to those of the elements to be manufactured which are fixed
by the fingers or projections on a second movable assembly to
; which the cable 141a of the winch 140 is clamped; alternatively
the second movable assembly is provided with a motor with a
reduction gear mechanism. The blocks 175 comprise a metal
web 176, steel wear resistant sleeves 177 passing through the
metal web 176 for receiving prestressing cables A and a friction
pad 178 at the lower end of the block 175 for contact with
; the metal plates of the moulding or work area. The web 176
and the sleeves 177 are preferably embedded in a suitable
` material 179, for example plastics material, an attachment
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member 180 for the projections or fingers of the second
movable assembly projects through the plastics material which
may be commercially available under the trade mark "Rilsan".
Reference will now be made to Figures 35-39 which
,~ illustrate the construction and the operation of the means
for feeding and distributing concrete in the moulds.
, :
E2. Means for Feeding and Distributing
: Concrete in the moulds
This principally comprises automated bucket 181
~,
10 displaceable along a track 182 straddling the bed and driven
v by a motor with reduction gear mechanism 183 supplied withcurrent through one or more electric cables 184 wound on a
drum 185. The drive means is preferably two speed, the
higher speed, for example in the range of 30 m/minute, is
used for the displacement of the bucket between the pouring
location and the concrete hopper while the lower speed, for
example in the range of 4 m/minute, is used for distributing
the concrete in the moulds of the bank.
. At the lower end of the bucket a pivoted drop gate
20 186 is provided enabling adjustable opening of the bucket by
........... means of a hydraulic or pneumatic jack 187 fixed to the outer
:. wall 188 of the bucket carrying on its opposite wall 189
. external vibrators 190 intended to regulate and facilitate
the descent of the concrete contained in the bucket. A hand
, . . .
i pump accumulator 191 provides the control fluid source for
~ .
`.~ the jack ].87, adjustment being effected by a lever 192.
.'~ In addition, vibrating means for the poured concrete
are fixed to the frame 193 of the bucket 181 and comprise
:.,.;: vibrating shoes 195 of steel, the number of which being
.~J 30 equal to that of the elements being poured along the width
?
of the bank, connected to each other, for example in groups
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of four or six, by a bearing bar 196 supporting a vibration
generator 197, the operating frequency of which being in the
~ range of 3000 Hz. A hood 198 protects the vibration generator
197 from straying concrete and a swinging chute 199 orientates
the stream of concrete from the bucket 181 forwards or
rearwards relative to the direction of forward displacement
shown by the arrow d.
F. Drive Means for the Moulding Unit
For the displacement of the two movable assemblies
a winch device 140 is provided (Fiyure 27) with two drums
200 and 201 having a slow operating speed and high starting
~- torque. The cable 141 is wound on the drum 200 and is adapted
to effect the forward movement of the movable assembly 125
whereas the drum 201 with the same operating torque but
having a different rotational velocity than that of the drum
200 winds the cable 141a connected to the second movable
assembly, the ends of the projections or fingers of which
carry the blocks 175, the electrobrake 207 for the motor with
a reduction gear mechanism of the winch device 140 maintaining
. 20 the cables 141 and 141a at constant tension when the winch
device is not operating. In a plant for the manufacture of
...
beams or girders of prestressed concrete by means of a
plurality of beds arranged in parallel, the device 140 is
preferably mounted on a track 202 perpendicular to the
lontitudinal axis of the bed so that a single winch device
is sufficient for controlling the moulding units on a
plurality of beds, a suitable work schedule being determined
~j:
for each bed.
In order to ensure the balancing of the pulling force
. . .
of the cables 141 and 141a, provision is made, parallel to
the rails of the track 202, for a forward abutment rail 203
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105703Z
with which a section 204 fixed to the frame of the winch
device 140 is adapted to co-operate and an anti-swing device
205 adapted to co-operate with a member 206 also fixed to the
frame of the winch device.
In another embodiment of the drive means for the
moulding unit (Figures 34a, 34b, 34c), the blocks 175 are
integral with a portal frame 301 comprising a beam 300 extending
along the entire width of the bed and lateral legs 302 in which
braking means 303 for fixing the portal frame in variable
positions along the length of the bed is provided. The
portal frame 301 may be displaced in the direction of the
arrow d which is the direction of the forward movement of the
unit during manufacture of concrete elements EL, by a winch
304 fixed on the forward cross member 127 of the first
movable assembly 125, the cable 305 being attached to the
, beam 300. A cable 306 of a winch 307 is also attached to
this beam 300. The winch 307 is fixed to the rear cross
member 128 of the movable assembly 125, the rear cross member
128 being adjacent to the retractable flap 160.
Alternatively, the displacement of the portal frame
301 may be effected by rack-and-pinion means, chain means,
jacks, friction rollers or the like.
G. Means for Positioning Transverse Reinforcements
Beams or girders of prestressed concrete comprising
longitudinal reinforcements must frequently be equipped with
transverse reinforcements, known as binders or stirrups, which
for elements of small dimensions may be formed as corrugated
~bars with two or three corrugations. For the positioning of
the transverse reinforcements in the freshly poured concrete
of the elements, there is provided (Figures 40 and 41) a
device which is a box-like drum 215 in the illustrated
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embodiment, mounted for displacement on a track 211 outside
the bed and comprising a portal frame 212 mounted for
rotation on its vertical legs 213 and 214 perpendicular to
said legs and for translation parallel to said legs. Cor-
rugated transverse reinforcements at are arranged along the
sides of the box and held thereon by quick opening clamping
means. The number of corrugated transverse reinforcements
at corresponds to the number of elements to be manufactured
across the width of the bed. ~
For putting a series of binders or stirrups at in
place in the freshly poured concrete, a hydraulic or pneumatic
device for the portal frame 212 controls the rapid descent
of the box-like drum 215 and the embedding of the transverse
reinforcements by vibration after opening the clamping device.
For the positioning of a second series of transverse reinforce-
ments, the box-like drum 215 rises, turns through 90 after
the portal frame 212 is displaced by movement along the track
211 and a procedure similar to that which has just been
described is started again.
H. Device for Heat Treatment of Moulded Elements
In order to speed up the setting of the concrete of
the moulded elements, it is proposed to bake them. With this
- aim in mind, all the elements on the bed are covered with a
tarpaulin 220 (Figure 42) of large dimensions, for example
3 x 60 m, adapted to be automatically rclled and unrolled by
a carriage 221 displaceable along the rails 222. In the
illustrated embodiment, the rolling and unrolling of the
tarpaulin is controlled by a motor 223 housed in the drum
~i 224 on to which the tarpaulin is rolled.
In a non-illustrated embodiment, a hand wheel is
used for rolling and unrolling the tarpaulin.
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The operation of the plant is described hereinbelow
with reference to Figures 43 and 44 which is a plant for
manufacturing beams and girders of prestressed concrete
utilising the method according to the invention complete
; with superstructure.
In such a plant, two beds 250 and 251, identical to
the one described hereinabove, are arranged in parallel in
a building structure of the type having an umbrella-type
roof 252 with curved plates of the Wonder Building (trade mark)
10 type as shown at the left in Figure 44, or light portal
structural work 253 as shown to the right in the same figure.
A propped portal frame 254 mounted on a track 255
at a distance of about one metre from the ground S is used
for handling while a concrete conveyor 256 is used for supplying
concrete to the bucket 181 displaceable along the track 182
of the bed 250, a service track 257 is arranged adjacent to t
, the track 182 for supplying raw materials to the beds 250
; and 251 as well as removing manufactured elements and the
like. The track 257 extends beyond the beds 250 and 251 at
; 20 the extreme right of Figure 54 to a storage area for
manufactured elements and to the other end of the bed to the
top storage areas 260 and 261 for the moulding equipment not
in service and then to an area 262 for the washing of this
equipment.
In the vicinity of the areas 260 and 261 and per-
; pendicular to the beds 250 and 251, the track 202 along which
: the winch 140 adapted to be associated with each of the
,, ,:
_moulding units operating on the beds 250 and 251 is displaceable.
For the manufacture of beams, girders or the like of
.j~` 30 prestressed concrete in the plant, the prestressing cables for
`` the series of elements to be manufactured are prepared by
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1057032
cutting a plurality of lengths of cable, and shaping the ends
of the lengths as a rivot or head adapting them to be secured
between the rectangular teeth 113a on the head for tensioning
and releasing the tension in the reinforcements. The reinforce-
ments which may be 60 to 100 m long are rolled in a coil which
is transported, for example, by the portal frame 254 onto the
bed 250. There, the ends of the cables without rivots or
heads are passed through the sleeves 177 in the blocks and
then are secured to one end of the bed, for example, the right-
hand side in Figure 43 on a traction head or a fixed anchorage
of the type illustrated in Figure 9.
. A head or comb for distributing the cables along the
;,
width of the bed is associated with the movable assembly
carrying the blocks 175, the displacement of the movable
assembly in the direction d (Figure 43) ensures the positioning
~,~ of the cables along the bed.
,
~ The free ends of the cables are then secured to the
:.
; traction head and all the cables are then simultaneously
tensioned.
,
~' 20 The manufacturing area comprising metal plates 3 is
i,,!,~. ~
heated.
The movable assembly 125 is, for example, at the
right end of the bed and secured against movement by the
braking device 142. The second movable assembly with blocks
175 is near the forward end of the movable assembly 125. The
;~ retractable flap 160 is in its lowered position thus delimiting
r''l with the blocks 175, the manufacturing area and the form
elements 126, the moulds into which the bucket 181 (previously
charged with concrete supplied by the concrete conveyor 256)
~` 30 pours the concrete for moulding the elements.
During a first phase of the pouring of the concrete,
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the swingin~ chute 199 is in the position shown in Figure 38
and the concrete delivered by the bucket is immediately
vibrated by the vibrating shoes 195. The bucket is displaced
slowly in the direction of the arrow _, and when a certain
length of the moulds are filled, the swinging chute 199 is
swung to the position shown in Figure 39. The bucket 181 is
then returned to its initial position by displacement in the
direction of the arrow _' and then is displaced once again in
the direction of the arrow d up to the forward end of the
movable assembly 125 thereby moulding the first portions of
the elements into which transverse binders at are introduced
by means of the device 210.
~ When the bucket reaches the vicinity of the forward
; end of the movable assembly 125 which is fixed against movement,
the braking device 142 is released; the hand wheel is manoeuvred
and the retractable flap 160 is raised while simultaneously
the actuation of the bars effect the rotation of the spindles
165 which brings the fingers or projections 164 parallel to
the prestressing reinforcements. In the case of a plant in
which the drive means for the moulding unit comprises a winch
device 140, this winch device 140, which was rolled along
the track 202 opposite the bed then in operation, is driven
by means of the drum 200, displacing the movable assembly 125
in the direction of the arrow _, the second movable assembly
with blocks 175 remaining fixed against movement.
The withdrawal of the first portions of the moulded
elements is thus ensured after the second movable assembly
_with blocks 175 is also displaced forwardly by the operation
of the drum 201 of the winch device 140, further portions of
elements are moulded according to the procedure which has just
been described.
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In a plant in which the drive means for the moulding
unit is as shown in Figures 34a, 34b, 34c, the withdrawal
of the first portions of the moulded elements is effected
by the winch 307, the braking device 142 being released while
the braking device 303 of the portal frame 301 is applied.
When the movable assembly 125 has been displaced the requisite
distance, the braking device 142 is applied, the braking
device 303 released and by the operation of the winch 304 and
the portal frame 301, to which the blocks are fixed for move-
ment, is displaced in the direction of the arrow _, and so on.
The recharging of the bucket 181 with concrete ispreferably effectuated during periods for removing the moulded
elements from their moulds by high speed displacement and
charging by the concrete conveyor 256, and then high speed
return along the axis of the bed which the concrete which has
just been charged is to be poured.
, After pouring the total concrete necessary for the
. moulding of the elements, the thermal insulating tarpaulin
,~ 220 is brought over the bed on which the elements are
;~,
supported, the enclosure formed by the bed and the tarpaulin
is heated according to a predetermined adjustable cycle.
; When the concrete has sufficiently hardened, the
means for tensioning and releasing the tension in the pre-
stressing reinforcements are rendered operative and after
rolling away the tarpaulin 200 by means of the motor 223, the
~, manufactured elements are removed from the bed by conventional
means with which the plant is equipped.
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