CA1115500A - Method and apparatus for manufacturing articles of hydraulic substances - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A method and apparatus are provided for manufacturing articles made of hydraulic cement. The method includes the steps of preparing a plurality of moulding spaces adapted to be closed in a hermetic manner and having sufficient pressure-proof against the inner pressure there-in, which pressure is raised during introduction and heat curing of hydraulic cement; introducing hydraulic cement into the mounding spaces substantially to fill the same by utilizing the pressure difference between the inner side and the outer side of the moulding space; indirectly heat curing the hydraulic cement substantially completely around the same immediately after the introduction of the cement is finished, the temperature thereof being rapidly raised up to more than 60°C, and releasing the cured articles from the moulding spaces. The apparatus includes a vertical stack of a plurality of moulds, each including a side frame and a hollow bed overlying the side frame; sealing means interposed between the side frames and the beds for hermetically sealing the moulds; means for releasably interconnecting the stacked moulds; means for reducing the pressure in the moulds; means for pouring the hydraulic cement into the moulds; means for admitting a heating medium into said hollow beds, for indirectly heat curing said hydraulic substance poured into said moulds. This invention thus enables the manu-facture of moulded articles of cement having high mechanical strength in a short time, and yet which can be readily removed from the moulds.

Description

This invention relates to a method and apparatus for manufacturing articles of hydraulic substances.
Various types of the method of manufacturing arti-cles of hydraulic substances e.g. cements, for example Portland cement, plasters, and calcium silicate have been proposed in the past. The method of manufacturing the arti-cles of hydraulic substances generally comprises a plurality of steps including compounding raw materials, pouring the raw materials into a mould, pretreating of the mould, surface finishing of the article and accelerating the curing of the article. Accordingly,, in order to sequentially perform such plurality of process r,teps, it is necessary to use a consider-ably large equipment :installed in a wide site. In mod,ern indust~ry, such process steps should be made in a flow system.
The curing treatment cr the curing acceleration treatment of the products requires at least several hours or more because hydration reaction should be suitably proceeded and sludge like substance mixed with water should be hardened to a hardness permitting removal of the hardened products from the mould. Such increase in the treatment time increases the area of the site required for the flow system. Further in order to accomplish the curing treatment in several hours it is necessary to preset particular heating and pressurizing conditions thus requiring a large installation. A]though the articles of the type described above are used as structural component elements for fabricating buildings and structures and manifest high compression strength their tensile strength is considerably smaller than metals as is well known in the art. For this reason, it is necessary to embed reinforming , - 2 ~

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steel rods in the produets. Moreover, for the purpose of passing sun light and wind and passing eonduits for electrie cables town gas,~water and sewage water, ete., it is usual t~ incorporate window frames and various pipings into the moulded artieles~ of hydraulic substances. Further, connect-ing members or fixtures are also incorporated into the arti-eles for the purpose interconnecting them or to mount thereon attachments. For this reason, it is advantageous to mould the art;eles of hydraulie substances wh-ich generally take the form`of flat plates with their wider side surfaces opened.
When the articles are moulded with their narrower side surfaces opened it would be diffieult to correctly embed such eonnectin~
members or fixtures, and in some cases it is impossible to do so. This requires a large labour and process steps. Where mould~-are arranged in a flow system with their wider side surfaces opened, a wide site and large equipments are required which require large eosts of installation and operation.
Modern factories designed for mass production of large con-crete articles require sites of several thousands square meter and employee of several tens or more.

It is an object of principal aspects of thi.s invention to provide a novel method and apparatus for manufacturing articles of hydraulic substances e.g. cements including Portland cement, silica cement, alumina cement, blast furnace cement, flyash cement and slag cement plasters, calcium silicate, etc., which can obviate many of the difficulties of the prior art methodSand can manufacture products of desired shape and characteristics with a relatively small equipment and with employees of small number.

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An object of other aspects of this invention is ko provide method and apparatus which can manufacture articles of hydraulic substances in a short time which have a large nlchanical strengkh and can be readily re~,oved from the moulds.
An object of still okher aspects of this invention is to provide a method and apparatus capable of manu~acturing on a mass production scale articles of hydraulic substances of various size and configuration in a -limited space such as a site close to or e~en in a parkially builk building. r An object of further aspects of this invention is to provide an improved method and apparatus for manufacturing a.rticles of hydraulic sub-stances wherein the substance is poured in the mould while the pressure in the mould is reduced thereby increasing the density oE the moulded articles~ ~.
An object of still a further aspect of this invention is to provide r portable apparatus for manufacturing articles of hydraulic substances which can be readily assembled, disassembled and transportedi to any desired site.
An object of another aspect of this inven-tion ls to provide a novel apparatus for manufacturing articles of hydraulic substances which utilizes beds composed of a plurality of units.
An object of other aspects of this invention is to provlde a method and apparatus for manufacturing articles of hydraulic substances which do not generate exces~ive noise during operation.
According to one aspect of this invention a method is provided for manufacturing articles of hydraulic cement, the method compri~ing the steps of: preparing a plurali-ty of airtightly closed moulding s~aces adapted to be closed in a hermetic manner and having sufficient pressure resistance /~
against the inner pressure therein, which pressure is raised during introduc- ~_ tion and heat curing of hydraulic cement; introducing hydraulic cement into said moulding spaces substantially to fill the same utilizing the pressure difference between the inner side and the outer side of the ~ulding space;
indirectly heat curing the hydraulic cement substantially completely around ~ t the same immediately after the introduction of the cement is finished, the temperature thereof being rapidly raised up to mDre than 60C, and releasing the cured articles from the moulding spaces.
By one variant, the moulding spaces are prepacked with aggregate before the hydraulic cement is introduced thereinto.
By a variation thereof, the pressure in the moulding spaces is re- ;
duced, and wherein the hydraulic cement is introduced into the moulding spaces under reduced pressure condition.
By another variant, the hydraulic cement is introduced into the moulding spaces by applying pressure on the cement.
By yet another variant, the method includes the step of inserting a formplate in the moulding spaces, thereby to make various pattern products. I ;
By a further variant, the hydraulic cement is one or more of cement mixtures, mortar, plaster and calcium cilicate.
By yet a further variant, the hydraulic cement is one or more of portland cement, alumina cement, silica cement, blast furnace cement, fly !~
ash cement, high-early-strength cement and slag cement.
By another variant, the method includes the step of disposing at least one of reinforcing steel rods, fittings, memhers adapted to intercon-nert the products, and fibers in the m~ulding space before the hydraulic cement is introduced thereinto.
By another variant, the method includes the step of dis~osing means for decreasing the weight o~ the product in the moulding space before the hydraulic cement is introduced thereinto.
By another variant, the means for decreasing the weight of the product comprises a sheet of foamed polystyrol. r-By another aspect of this invention, a method is provided for manufacturing articles made of hydraulic cement comprising the steps of:
preparing a plurality of airtightly closed mDulding spaces adapted to be c ~ 4 ,' . , `'~ , ',` . ~
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closed in a heLmetic manner and then having sufficient pressure-resistance against the inner pressure therein which is raised during heat curing of the cement; introducing hydraulic cement into the moulding spaces by ~tiliz- t ing the pressure difference between the inner side and the outer side of the moulding space; indirectly heat curing the hydraulic cement in the mDulding space substantially completely therearound immediately after the introduc-tion of the cement is finished, the temperature being rapidly raised up to more than 60C, during which the pressure in the space is increased higher r than the expansion pressure of the cement; and releasing ~he cured articles from the moulding spaces.
By a variant thereof, the hydraulic substance is one or nDre of cement mixtures, motar, plaster and calcium silicate. ~`
By another variant, the m~ulding spaces are packed with coarse aggregate before they are poured with the hydraulic substance.
By yet another varian~, the method includes the step of recovering a mould containing an article which has been sufficiently cured to a state to be releasable from one side of the stac~ of the plurality of moulds; and adding an empty mouLd to the other side of the stack, thus c~ntimlously manufacturing the articles.
sy a further variant, the hydraulic substance is poured subst~nti-ally simultaneously in all m,ouLds of the stack thus manuEacturing the articles by a batch system.
By yet a further variant, the method includes the steps of establishing tw~ stations in a field of fabricating structures, a stacking a plurality of m~oulds in one station for manufacturing the articles of the hyclraulic substance; disassembling thè stacked moulds in the one station and stacking the transferred ~oulds in the other station for mRnufacturing the articles.
By yet another variant, tha heat curiny of the hydraulic substance .
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of the hydraulic substance poured into the moulds is effected by a hea-ting medium admitted into the beds.
By a variation thereof, the heating medium comprises steam or hot ?
water.
By another variant, the hydraulic celr~ent poured mto the mDulding spaces is heat cured and then is cooled to harden the hydraulic cement.
By another variant, the method includes tha steps of firmly inter-connecting the hollcw beds each other for resisting the pressure raised dur-ing the introduction and the heat-curing of the cem?ont; and introducing the hydraulic cement into the moulding space by utilizing the pressure differ-ence between the inner side and the outer side of the mould.
By a variation thereof, the pressure in tlhe moulding spaces is reduced and wherein the hydraulic cement is introduced into the moulding spaces under reduced pressure condition.
~y another variation, the ~lydraulic c~men-t is introduced into the moulding spaces by applying the pressure on the cemLnt.
~y still another aspect of this invention, a continuous method is provided for sequentially manufacturing articles made of hydraulic cement wherein a plurality of Ir.oulds are ver-tically stacked) the stack haviny a feedside and a discharge side, each mould including a side frame and a hollow bed with a bottom plate overlying the frame so that the bottom plate of one mould covers the side frame of the next mould, and ~Jherein sealing members are interposed between the beds and the moulds throughout the stack for airti~htly closing the moulds, the method consisting essentially of: reducing the pressure in the mould at the feed side of the stack; introducing ~he hydraulic cement into the m~ould under the reduced pressure con~ition; in-troducing a heating medium into the hollc~ beds surrounding the moulds for gradually heat curing the poured hydraulic cemlnt from the feed side to the discharge side of the stack; advanciny each mould by one step at a time - 4 c -. . , : ' ' :: ,.

L5~;~0 through the stack from the feed side to the discharge side thereof, so that each miould occupies the position of thè preceding mould as it advances through the stack, the curing of the hydraulic cement taking place at different stages throughout the stack of the moulds; remDving one mould con-taining an article made of hydraulic cement which has been sufficiently cured, from the discharge side of the stack; and preparing a fresh mould at the feed side of the stack where it is recharged with the hydraulic cement, thus oontinuously manufacturing the articles. r By yet another aspect of this invention, a continuous method is 10 provided for sequentially manufacturing articles made of hydraulic cement wherein a plurality of moulds are vertically stacked with a plurality of hollcw beds alternately disposed therebetween, the stack having a feed side and a discharge side, the method consisting essentially of: reducing the pressure in the mould disposed at the feed side of the stack; introducing hydraulic cement into the mould under the reduced pressure condition; intro-ducing a heating medium into the hollow beds surrounding the moulds for gradually heat curing the poured hydraullc cement from the feed side to the discharge side of the stack; advancing each mould and adjacent beds by one step at a time through the stack from the feed side to the discharge side 20 thereof, so that each mol~ld occupies the pesition of the preceding mould as it advances through the stack, the curing of the hydraulic ce~lent talcing place at different stages throughout the stack of the moulds; removing one mould containing an article made of hydraulic cement which has been suffici-ently cured,fxom the discharge side of the stack of the plurality of moulds;
and preparing a fresh mould and bed at the feed side of the stack where the $~
bed is recharge~ with the hydraulic cement, thus continuously manufacturing ~-the articles.
As noted hereinbefore, an object of another aspect of this inven-~ 5 ~
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According to another aspect of this invention, the apparatus is provided for r~anufacturing articles of hydraulic cement comprising a vertical s-tack of a plurality of moulds each including a side frame and a hOllc~r7 bed overlying the side frarr.e, sealing means interposed bet~7een the side frarnes and the beds for hermetically sealing the moulds, means for releasably inter- ~
connectiny the stacked moulds, means for reducing -the pressure in the moulds, r means for pouring the hydraulic substance into the moulds, and means for ad-mitting a heating medium into the hollcw beds for indirecl:ly heat curing the hydraulic substance poured into the moulds; and means for releasing the articles from the mould; ~`
By one variant, the apparatus further includes means for releasably connecting the means for adrritting the heating mediurn into the beds ar~l the means for pouriny the hydraulic substance into the moulds to the side fram.es.
By another variant, the periphery of ecach hollo~.7 bed extends be-yond the periphery of each side frarne so as substantially uniformly to heat J~
cure the hydraulic substance poured into the side frame by the heating medium admitted into the hollc~7 bed. ~t By yet another varian-t, the sealing rneans comprises: an inner seal-ing mernber for sealing the hydr.aulic substance poured into the mould; and an outer sealing Ir~er for sealing air; and ~^/herein the space between the inner and outer sealing ~ers is connected to a source of reduced pressure.
By a still further variant, the apparatus further cornprises: means for adding an empty mould to one side of the stack; and ~ans for rernoving, i-.
frcrn the other side of the stack, a mould containing a cured and releasable article of the hydraulic substance.
By another variant, the apparatus further ca~r~rises: suI~porking means for supporting the stack; and F.eans for elevating the stack.

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By a varia-tion thereoE, the supporting means supports the stack at more than two spaced points around the periphery of the mould. r By another variation, the supporting means and the elevatinq means i' are mounted on the same bed.
By another variant, each of the holla^7 beds has arcuate top and bottom plates so as to produce articles having an arcuate cross-sectional configuration.
By another variant, the interconnecting means oomprises: a cylinder F
piv~tally mounted on one bed, a head supported by the piston rod of a piston contained in the cylinder and adapted to engage another bed, the another bed being provided with a notch for receiving the piston rod.
By a variation thereof, the piston rod includes means for varying r the length thereof.
By another variation, the apparatus includes a pair of transverse pins connected to the opposite sides cf the cylinder; a pair of side pla-tes secured to the one bed on the opposite sides of the cylinder, the side plates being provided with curved slots for relea.sably receiving the pins; a ~~
pair of supporting plates respectively connected to the outer ends o~ the pins; and means for releasably connecting the .supporting plates to the side plates.
By another variant, the means for pouring the hydraulic substance co~prises: a pouring tube connected to the inlet opening of the side frame; a piston slidably oontained in the pouring tube; and ~eans for operating the piston to open and close the inlet opening.
By a variation, the apparatus further comprises: a conduit connected to the pouring tubP for supplying thereto the hydraulic substance;
and means for supplying cleaning liquld into the p~uring tube.
By another variation, the means for supplying the cleaning liquid includes: means for supplying the cleaning liquid into the pouring tube from the opposite sides ~hereof.

~ ` . I ` _ ~ 7 -- By another variant, the btack of the moulds is fabrica-ted in one of a plurality of stations established in the field of constructing a structure, and wherein yards for collecting coarse aggregate, fine aggregate reinforcing steel rods and cement are located about the stations, together with a source oE a mortar mixture, a source of reduced pressure and a boiler.
By yet another variant, each bed comprises: a plurality of flat units; and means for interconnecting the UllitS in end-to-end relationship to form an integral wider bed. r By a variation thereof, the units comprise: positioning ~mbers at their ends to be joined; and a sealing member interposed between the joined ends; the positioning members being shaped to cooperate each other for maklng flush the upper surfaces of the units when they are cQmbined into an integral bed.
By another variation, the apparatus further comprises: a reinforc-ing member including an opening for loosely receiving a positioning member and provided for one end of each bed unit; means for securing the position~
ing members to the reinforcing m~mber in correct axial position; and means ~~
extending through the opem ngs of the positioning members of both bed units ~t'for integrally joining the bed units.
By a variation thereof, the positioning members oE both bed units are provided with complem~ntarily inclined surfaces which engage each other for centering the positioning members.
By another variation, the sealiny ne~ber is retained by a pair of inwardly inclined holding members secured on the inside of the bed units at the confronting ends thereof.
By a further variation, a plurality of the interconnecting m~mbers r-are provided at different levels.
By another variation, the interconnecting members comprise: shorter members; and longer members; the shorter mmbers being used to interconnect the positioning members of the bed units; and the longer mem~ers having a length to extend over the width of the integral bed, thus clamping to-gether the bed units on t'neir opposite ends.
By a further variation, the sealing member comprises an inflata-ble tube.
By another variant, the apparatus further comprises: a source of pressure; and means for connecting the interior of the moulds to the source of pressure for applying pressure to the hydraulic substance after it has been poured into the moulds.
By another aspect of this invention a method is provided for manufacturing articles of a hydraulic substance comprising: stacking an open-topped mould chamber defined by a side frame mounted on a hollow bed, the bed having a bottom surface which covers the next successive lower chamber to form a closed moulding space, airtight sealing means being in-terposed between the bed and the next successive lower mould around the said mouldlng space; filling the moulding space with the hydraulic sub-stance; heat curing the hydraulic substance in each moulding space by ad-mitting a heating medium into the hollow beds between which the moulding space lies; and releasing cured articles from the moulds.
By one variant, the step of filling the moulding space comprises:
reducing the pressure in each moulding space and filling the moulding space with the hydraulic substance while the moulding space is under re-duced pressure.
By another variant, the hydraulic substance is selected from the group consisting of cement mixtures, mortar, plaster and calcium silicate.
By still another variant, each mould is packed with coarse aggregate before it is filled with the hydraulic substance.

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By yet another varlant, each mould i5 partially filled with the hydraulic substance before its mould chamber is closed.
By a further variant, the moulding spaces are filled in succes-sion and their contents are heat cured in succession.
By another variant, a mould containing an article which has been sufficiantly cured to a state to be releasable therefram is removed from ;
one end of the stack of the said plurality of moulds; and wharein an empty !' mould is added to the other end of the stack, thus substantially continu-ously manufacturing the articles.
By yet another variant, the plurality of moulds are stacked in one station for manufacturing the articles of the hydraulic substance;
wherein the stacked moulds in the said one station are disassembled and transferred to another station, and wherein the transferred moulds are again stacked in the said other station for manufacturing further articles.
By a further variant, the heating medium is steam.
By a further variant, the heat cured hydraulic substance is cooled to harden the hydraulic substance before it is relaased from the mould containing it.
By yet another variant, at least one element is selected from reinforcing steel rods, fittings, members adapted to interconnect the articles, and means for decreasing the weight of the article is mounted in the mould before the mould is filled with the hydraulic substance.
By a variation thereof, the means for decreasing the weight of the article comprises a sheet of foamed polystyrol.
By another aspect of this invention, an apparatus is provided for manufacturing articles of a hydraulic substance, comprising: a plurality of moulds stacked one on top of another, .~
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each mould comprising an open-topped mould chamber defined by a side frame mounted on a hollow bed, the bed having a bottom surEace which covers the next successive lower mould chamber to form a closed moulding space, air-tight sealing means being interposed between each bed and ~he next suc-cessive lower mould around the said moulding ~pace; means for releasably interconnecting the beds; means or supplying the hydraulic substance to the moulding spaces; and inlet means for admitt~ng a heating medium into the hollow beds.
By a variant thereof, the periphery of each hollow bed extends beyond the periphery of each side frame, so as substantially uniformly to heat cure the hydraulic substance poured into said side frame by the heat-ing medium admitted into said hollow bed.
By another variant, the apparatus includes means for reducing the pressure in the moulding space.
By a variation thereof, the pressure reducing means is selective-ly connectible to each moulding space separately.
By a further variation, the sealing means comprises: an inner sealing member for selaing said hydraulic substance poured into the mould;
and an outer sealing member for sealing air; and wherein the space be-tween the said inner and outer sealing members i8 connected to a source of reduced pre~sure.
By another variant, the apparatus further includes: at one end of the stack, transport means for addlng an empty mould to the said one end of the stack; and, at the other end of the stack, transport means for removing, from the said other end of the stack, a mould containing a cured article of the hydraulic substance.
By a still further variant, the apparatus further includes:
supporting means for supporting the stack, and means ~,~, ".
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for elevating the stack.
By yet a variation, the supporting means supports the stack at i three spaced points around the periphery of the stack.
By another variation, the supporting means and the elevating means act on the same bed.
By yet another variation thereof, each one of the hollow beds has arcuate top and bottom plates so as to produce articles having an ar-cuate cross-sectional configuration.
By a further variant9 the interconnecting means comprises: a cylinder pivotally mounted on one bed and a head supported by the piston rod of a piston contained in the cylinder; an adjacent bed belng provided with a notch for receiving the piston rod upon pivoting of the cylinder.
By a variation thereof, the piston rod includes means for vary-ing the stroke thereof.
- By a further variant, the apparatus further includes: a pair of pins connected to the opposite sides of the cylinder and extending t~ans-versely of the cylinder; a pair of side plates secured to the said one bed on the opposite sides of the cylinder, the side plates be.ing provided wlth curved slots for releasably receiving the pins; a pair of supporting plates respectively pivotally connected to the outer ends of the pins; and means for releasably connecting the supporting plates to the side plates.
By another variant, the means for supplying the hydraulic sub-stance comprises: a pouring tube. connected to an inlet opening of a said side frame; a piston slidably contained in the pouring tube, and means for operating the piston to open and close the inlet opening.
By a variation thereof, the apparatus further - 9c -::, includes: a conduit connected to the pouring tube for supplying thereto the hydraulic substance; and means for supplying cleaning liquid to the pouring tube.
By yet another variation, the means for supplying the cleaning liquid supplies cleaning liquid to the pouring tube at more than one posi-tion.
By another variant, the stack of moulds is fabricated in a con-struction site, and wherein yards for collecting coarse aggregate, fine aggregate, reinforcing steel rods and cement are located a~out the site, together with a mortar mixer and a boiler.
By yet another variant, each bed comprises a plurality of units;
and including means for interconnecting the units in end-to-end relation~
ship to form the bed.
By a still further variation, the units comprise: positioning members at their ends to be joined; and a sealing member interposed be-tween the joined ends; and wherein the positioning members are shaped to cooperate with each other for making flush the upper surfaces of the units.
By another variation, the positioning members pass through open-ings in reinforcing members at the said ends of the ~mits; wherein means are provided for securing the positioning members to the reinforcing mem-bers; and wherein the positioning members have openings receiving a connect-ing member for integrally joining the units.
By yet another variation, the positioning members of adjacent units are provided with complementarily inclined surfaces which engage each other for centering the positioning members.
By still another variation, the sealing member is retained by a pair of inwardly inclined holding members secured on the inside of the units at the confronting ends thereof.

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By yet a further variation the sealing member i9 an inflatable tube.
By a further variation, each bed has a plurality of the said interconnecting means.
By yet another variation, each bed has a plurality of the said interconnecting means and wherein the said interconnecting means comprises shorter connecting members interconnecting adjacent ends of adjacent bed units and longer connecting members interconnecting remote ends of the bed units at opposite sides of the bed.
By another variant, the apparatus further includes: a source of pressure, and means for connecting each moulding space to the source of pressure for applying pressure to the hydraulic substance after the mould space has been filled.
In operation of the apparatus and method of aspects of this in-vention, an empty mould is added to one side of the stack while another mould containillg a cured article is removed from the other side of the stack. In this manner a number of articles is continuously manufac-tured on a mass production scale.
Since a plurality of moulds is stacked in the vertical direction, the apparatus of an aspect of this invention occupies only a limited floor space so that the apparatus can be installed or transported to any desired site near a building under construction or even on a floor of a partially fabricated building. Further, the mould is open at its wider side so that it is easy to charge aggregate, and to mount therein reinforcing steel bars, pipes, fittings, w~ndow frame~ or means for interconnecting the completed articles. If desired, layers of heat insulating, heat preserving or sound absorbing material may be disposed in the mould before pourlng of the hy-draulic substance.
Further, as a number of moulds are stacked in the vertical direc-tion, the hydraulic substance charged in respective moulds acts as a heat - 9e -. : ' :

insulator, thus establishing an optimum temperature gradient along the height of the stack. As a consequence, it is not necessary to use any separate and distinct heat insulated chamber for heat curing the poured hydraulic substance and then cooling the cured products. Even when pres-sure is applied to the poured hydraulic substance during curing, the layers of such poured substance act as a cushion for the applied pressure thereby substantially eliminating means for resisting against such applied pressure.
An important feature of an aspect of this invention lies in the reduction of the pressure in the mould during pouring of the hydraulic sub-stance. This enables pouring the hydraulic substance in closed moulds by adifference between the atmospheric pressure and the reduced pressure pre-vailing in the. moulds. Moreover, it is also possible to remove air en-trained in the hydraulic substance (usually 2 to 3% of air is entrained~
and excessive moisture as well as the air in the interstices between coarse or light weight aggregate packed in the moulds, thereby increasing the density and compression strength of the products. In addition, when heat is applied for curing, a pressure higher than atmospheric pressure is created in the mould, thus further compacting the poured hydraulic sub-stance. For example, when the moulds are heated to 100C, a pressure of 1 Kg/cm2 will generally be created in the moulds. If the pressure in themoulds is reduced to 0.1 Kg/cm2, the material used to fabricate the moulds is required to withstand to a pressure of 2.0 Kglcm . Since it is possi-ble successively to pour the hydraulic substance into the stacked moulds, the temperature difference between one mould whose internal pressure has been reduced to 0.1 Kg/cm2 and an adjacent mould which is heated for curing is at most 30C, so that the maximum pressure of expansion would be less than 0.2 Kg/cm2. Accordin~ly, the pressure difference acting upon the material comprising the moulds would be 1.1 Kg/cm . As the curing temperature is increased to 80C3 the pressure of expansion would be _ . :

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0.5 Kg/cm and the pressure dif:Eerential to which the material is sub-jected is only 6.3 Kg/cm2~ In other words, the material is required to withstand to a pressure of only 1 Kg/cm2. This decreases the weight and size of the apparatus oE aspects of this invention.

- 9ff -It i8 advantageous that the sealing member interposed between the bed and the mould be constituted by an inner sealing member for substantially preventing the leakage of the poured hydraulic substance and an outer sealing member for preventing the leakage of air. The space between the inner and outer sealing members is generally connected to a source of reduced pressure, or to a source of pressure for establishing a desirable pressure gradient be-tween the inside and the outside of the moulds. If the inner sealing member were made of metal, it will not be damaged by tha concrete poured in the mould, and the concrete deposited on the metal sealing member can readily "
10be wiped off.
Generally speaking, the apparatus of an aspect of this invention !
requires a floor space of only twice of the surface area of the products.
For example, where the products have a surface area of several square meters, the floor space required may be less than 20 m .
To ease the assembly, disassembly and transporting of the bed, according to another feature of the invention, the bed is compsoed of a plurality of split bed units which are joined together into a unitary structure.
In the prlor method of manufacturing concrete articles, it was 20usual to apply vibration to the mould for the purpose of densely compacting the mixture of aggregate and the hydraulic substance. However, such vibra-tion generates obJectional noise. As described hereinabove, according to aspects of this invention since the pressure in the mould is reduced and then the hydraulic substance is poured into the mould under the prassura difference between the reduced pressure and the atmospheric pressure3 it is possible to produce dense products without applying any vibration to the mould. If desired, after pouring the hydraulic substance in the mould, the pressure therein may be increased beyond atmospheric pressure for further compacting the poured hydraulic substance.
Fig. 1 is a plan view of the apparatus embodying an aspect of the _~ _ gg _ , ' ~
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invention which is suitable Eo~ a continuous production system;
Figo 2 is a side view, partly in section, of the apparatus shown in Fig. l;
Fig. 3 is a side view showing a group of stacked moulds, a pres-sure reducing mechanism, and a heat curing means utilized in the apparatus of an aspect of this invention shown in Figs. 1 and 2;
Fig. 4 is a partial sectional view showing a connecting member and sealing members utilized in the apparatus of an aspect of this inven-tion shown in Figs. 1 and ~;
Fig. 5 is a sectional view showing various members shown ln Fig.
4 before assembly;
Fig. 6 is a partial perspective view showing the manner of mount-ing the sealing members;
Fig. 7 is a partial sectional view showing a modified connecting member and sealing members;
Fig. 8 is a plan view showing one example of a support utilized in the apparatus of an aspect of this invention;
Fig. 9 ~s a side view of the support shown in Fig, 8/
Fig. 10 shows a cross-sectional of the support shown in Fig. 8 taken along a line X-X.

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Fig. 11 is a side view of the novel apparatus of an~ther aspect of this invention utilized to manufacture arcuate segments;
Fig. 12 shows a plan view of a bed utilizing modi-fied connecting means for interconnecting adjacent beds;
Fig. ~3 is an enlarged sectional view taken along a line XIII-XIII shown in Fig. 12;
Fig. 14 is a side view, partly broken away, of the assembly shown in Fig. 13 as viewed from the lefthand side;
Fig. 15 is a longitudinal sectional view o-f a pouring ~evice of the hydraulic substance provided with cleaning means;
Fig. 16 is a plan view of the pouring devLce shown in Fig. 15;
Figs. 17a, 17b and 17c are diagrammatic side views showing a manner of fabricating the stack of the moulds alternately in one and other stations in the field;
Fig. 18 is a plan view of the field showing an arrangement of the fabricating stations and yards for collect-ing various raw materials, a boller, a pressure reducing means, etc., Fig. 19 is a side view of a stack of a plurality of moulds in which each bed is comprised by two bed units;
Fig. 20 is an enlarged sectional view of the joined ends of two bed units;
Fig. 21 is a diagrammatic sectional view showing the position of reinforcing flanges and Fig. 22 is an enlarged sectional view showing a modified sealing member interposed between two bed units.

The embodiment of this invention illustrated in -- 10 -- .

.

~s~

Figs. 1 and 2 is suitable for continuous production systems and the details of the apparatus is shown in Figs. 3 through 10 .
A loading mechanism 41 as shown in Fig. 2 is pro-vided on one side of a moulding station A surrounded by suitable walls 50 for loading a hydraulic substance from a hopper 42 into moulds 1. Each mould 1 comprises a side frame 11 and a hollow bed 12 including a bottom plate 15. In the moulding station A, a plurality of moulds 1 are piled up, and the hydraulic substance is poured in the uppermost mould 1. A c~nveyor 3 shown as a roller conveyor is disposed beneath the lowermost mould 1 for transferring the lowermost mould to a releasing station B on one side of the moulding station for removing a completed product 100 from the mould 1. At this time, the product has been sufficiently cured and can be readily removed from the mould. The removed products 100 are transferred to station C at which the products are piled up for transportation. Three supports 4 are provided along the periphery of each mould 1 for removing the same.
Further, three elevating means such as jacks 5 are also provided along the periphery of each mould. The construction and operation of the supports 4 and the jacks 5 will be ;
described later in detail.
Fig. 3 shows the detail of the moulding station A.
As shown, the coarse aggregate is loaded into respective side frames 15 by means of the loading mechanism 41. Another load-ing mechanism 13 is provided for loading into the moulds 1 mortar of a hydraulic substance, for example, paste like cement !
Spacers 14 are interposed between adjacent moulds 1, -;~
a preferred spacer being shown in Figs. 4 and 5. The support-ing member 4a of the support 4 is received in a perforation 12d of the bed 12 of one mould 1. However, it should be understood that other supporting means can also be used. In the illustrated example, the supports 4 and the elevating means S are arranged such that, while the second mould 1 from bottom is being supported by the supports 4 the lower-most mould 1 is lowered onto the conveyor 3 by the elevating means 5. Alternatively, the lowermost mould 1 is elevated together with the moulds thereabove by means of the elevating means 5 arld then all moulds are supported by the supports 4 in their elevated position. Thereafter, another mould loaded with the hydraulic substance is slippea into the space beneath the lowermost mould. Then the uppermost mould containing a cured or releasable product is removed. One example of such alternative arrangement will be described later with reference to Figs. 8, 9 and 10. In the example shown in Fig. 3, a new mould to be loaded with poured the hydraulic substance is added from above to the assembly. However, where it is advantageous to fabricate reinforcing steel bars in the moulds while they are maintained on the ground, the apparatus shown in Figs. 8, 9 and 10 is preferred in which case the direction of movement of respective moulds is reversed from that shown by arrows in Fig. 3.
In the example shown in Figs. 1 and 3 eight moulds 1 are piled up thereby greatly decreasing the floor space than in the conventional flow system in which respective Moulds are placed side by side relationship on the same plane. Even when large products having a surface area of several square meters are to be manufactured, the apparatus embodying an aspect of this invention 12 - .

.

requires a ~loor space of only 20 square meters.
Moreover as the moulds are arranged horizontally with their wide upper surfaces completely opened it is easy to fabricate reinforcing steel bars or to mount fittings or the like in the moulds. Loading of the coarse aggregate and the hydrau-lic substance such as cement (a mixture of cement, a fine aggregate such as fine sand, fibers, metal wires, plastics, etc.) is also easy. The above described horizontal arrange-ment of the moulds wherein the moulds are held with their wider side surfaces completely opened is especially advan-tageoUS for producing products having light weights, high mechanical strength, excellent heat insulating property, heat preserving property, sound absorbing property or other desirable properties by placing at a definite and uniform spacing light weight, heat insulating, heat preserving or sound absorbing bodies which are shaped into desired configu-rations (polygon, sphere or cylinder, for example). These advantageous properties are obtained only when such bodies are loaded with a definite and uniform spacing in the mould.
The arrangement of the moulds described above enables such uniform distribution.
The beds 12 including the bottom plates 15 complete-ly close the upper and lower surfaces of the moulds when they are stacked each other. Thus, when the hydraulic substance is poured into are given mould 1 by the loading mechanism 13 the bottom plate 15 of the upper mould acts as the cover plate for the given mould thus producing a moulded product having a smooth upper surface which does not require later finishing operation. When supporting the bed 12 by the supporting members 4a it is advantageous to interpose a load carrying member 16 (Fig. 4) between the moulds and vertically above the supporting members 4a. With this arrangement the load of respective moulds is supported by the suppor~ing members 4a of the supports thus relieving the moulded arti-cles in respective moulds from the load applied thereto from ; upper moulds.
Preferably, the charging mechanism 13 comprises a closed tank and an opened tank and by reducing the pressure in the closed tank by means of a pressure reducing apparatus the h~draulic substance is poured into the moulds as will be described later.
The three point supporting system desc~ibed above also relieves the moulded products in the moulds from the load applied tbereto from above. Although ~four or more supporting points can also be used in aspe~ts of this inventiOn, such supporting system requires that the supports 4 and the elevating means should be extremely accurate and should operate uniformly. If there are difference between the heights of the supports and between the heights of the elevating means, the weight of the piled up moulds, which generally amounts to several tens tons will be applied to the products thus fracturing or crackinq the same. According to the three point supporting system of an aspect of this invention it is possible to stably support the moulds so that there is no fear of damaging the moulds and the products contained therein.
According to an aspect of this invention, for the purpose of facilitating charging of the hydraulic substance into closed moulds and improving the quality and mechanical strength of the products suitable pressure reducing means is used.

-:

One example of the pressure redueing means illustrated in Fig. 3 comprises a pressure redueing means 45, e.g a vaeuum pump mounted on a supporting frame 44. The vaeuum pump 45 is eonneeted to the mould through an air-water separator 46, a valve 47 and a flexible horse 48 whieh is connected to a perforation 24 shown in Figs. 4, 5 and 7 in a manner to be deseribed later for subjecting the substance poured in the mould to a reduced pressure Further, in accordance with another aspect of this invention, means is provided for aeeelerating the euring of the hydraulie subs~,~nee poured into the mould. As is well known in the art, a hydraulie substanee e~g. eement is eured or hardened by aeeelerating the hydration reaetion of the sub-stanee. Sueh hydration reaetion ean be aceelerated by heating. In the embodiment shown in Fig. 3 a distributor 58 eonneeted to a source of heating medium such as a boiler ~not shown) is mounted on the supporting frame 44 ~or direct-ing the heating,medium into the hollow beds of respeetive moulds 11 via a plurality of branch conduits 52. As shown in Figs. 4 and 5 eaeh bed 12 takes the form of a closed box so that the heating medium introdueed into the bed heats the substanee poured into the moulds from both sides. Accordingly, the hydration reaction of the hydraulie substance in the moulds,is accelerated whereby the curing is completed in a ;
short time thus producing hard or releasable products. As shown the periphery of the bed projects laterally beyond the , -periphery of the mould so that the bed prevents the mould from being cooled by the ambient air with the result that the mould is uniformly heated. For this reason it is possible to efficiently cure the product without installing a special ;s~

curing room. When the heating medium is introduced into the bed under a pressure, small openings, not shown, may be pro-vided at suitable portions of the bed to decrease the pressure.
Where the heating meaium is steam, drain openings, not shown, for the condensate may be provided for the bed. The tempera-ture and the temperature gradi~nt of the heating medium suitable for use in this invention will be described later in connection with the preferred embodiment.
One example of the preferred connecting means for interc~nnecting adjacent moulds and sealing member interposed betweell ~he beds and the moulds are illustrated in Figs. 4 and 5, and the manner of mounting the sealing members upon the side frame is shown in Fig. 6. As has been pointed out hereinabove, the bed laterally projects beyond the periphery of the mould. As shown in Figs. 4 and 5 each bed comprises I
beams i2a on the periphery and a upper plate 17 and a bo-ttom plate 15 which are secured to the upper and lower surfaces of the I beams 12a. The periphery of the mould is comprised by channel beam lla. A paste or concrete sealing member 18 is mounted on the inner side of the channel beams lla and an air sealing member 19 is mounted on the outer side of ;~
the channel beams on both sides thereof.
In the example shown in Figs. 4 and 5, for the purpose of interconnecting adjacent moulds, perforations 20 are formed through the periphery of the bed 12 which projects beyond the periphery of the mould and through the upper and lower flanges of the I beam 12a for receiving a connecting member shown as a bolt 21. ~ith this connecting means it is possible to readily add another mould, to the upper side or lower side to the assembly of the moulds. Further, it is i5~

possible to disconnect moulds containing cured products 100 from the upper or lower side of the assembly. To facilitate such operations a flange 22 is formed at an intermediate point of the bolt 21 and a nut 23 is screwed onto the threaded end 21a of the~bolt 21. Thus, after inserting the bolt 21 through the perforation 20 of the upper plate 17 of a lower bed 12 until the flange 22 seats on the plate 17 the lower nut 21b screwed and fixed by spot welding as shown in ~ Fig. 5 anupper bed 12 can readily be connected to the lower bed by inserting the upper portion of the bolt into the perforation 20 through the lower plate 15 of the upper bed and through the lower flange of the I beam 12a thereof and then tightening the nut 23. To remove the lowermost mould containing a cured product from the bottom of the stack of the moulds shown in Figs. 1 and 3, reverse operation is done. i-The lowermost mould disconnected in this manner is conveyed to the releasing station lOO by means of the conveyor 3.
The paste sealing members 18 may be made up metal because they are used for preventing paste from flowing out-wardly of the mould whereas the air sealing members 19 aremade of rubber or pliable synthetic resins so as to form air tight seals. The pressure in the spaces 25 between the shields 18 and 19 is reduced by connecting the spaces to the pressure reduciny means 45 through openings 24 and flexible horses, not shown. When the pressure in the spaces 25 is reduced in this manner, the paste sealing members 18 manifest but little resistance to the flow of air. Denoting the atmospheric pressure by P, the pressure in the spaces 25 by Pl, and the pressure in the mould by P2, then a relation P>Pl~P2 holds. This equation shows that a reduced pressure 5~

is applied to the content of the mould. However, sin~ Pl and P2 are substantially equal, the content is subjected to the pressure of the pressure reducing means. Even when the air sealing means 19 contains some defects ~hat leak air, as such air leaks into the space 25 which is constantly evacuated by the pressure reducing means 45, the pressure in the mould would not~be affected by such leaking air. Thus, the spaces 25 function to act as cushions for the invading air thus preventing it from increasing the pressure in the mould. With the novel sealing means, the paste such as cemen~ i~ the mould contacts only with the paste sealing members 18 and not with soft air sealing members 19 so that these air sealing members 19 would not be damaged by the cement. -Accordingly, after use of the mould, it is neces-sary ~o ~lean or repair only the paste sealing members 18.
Fig. 6 shows a manner of mounting the sealing members 18 and 19 onto the side frame 11 of a mould, parti-cularly a corner thereof. More particularly, channel beams lla are connected together as shown by solid lines in Fig. 6 to form the side frame 11. As shown, side plates 26 are secured to the abutting ends of one channel beams lla which is faced to the back of another channel beams lla, and the sealing members 18 and 19 applied to the upper surfaces of respective channel beams lla are turned down-wardly as shown by 18a ana l9a at the joint and then applied onto the lower surfaces of the I beams lla to form the lower sealing members 1~ and 19 as shown by the dotted lines.
In this manner, the lower and upper sealing members 18 and 19 are formed by continuous strips so that there will be formed no gaps or discontinuities thus providing effective 5~

sealing means all around the periphery of the side frame.
When two I beams lla are joined together, the sealing membexs 18 and 19 are also joined together at their depending portions 18a and lga. Moreover as such depending portions 18a and l9a are clamped between the abutting ends of the I beams the joint is effectively sealed.
Fig. 7 shows modified connecting means and sealing means. The construction of the connecting means and the sealing means shown in Fig. 7 is the same as that shown in Figs. 4 and 5. The bolt 21 is provided with an intermediate flange 22 and threaded portions 21a on both ends. Nuts 23 and 28 are threaded on each threaded portion 21a for clamping the Elanges of the I beams and the top and bottom plates 17 and i5 of adjacent beds 12. With this construction, the bolt 21 not only functions to interconnect adjacent beds 12 on the opposite sides of the side frame 11 of one mould but also functions as the load carrying member 16 shown in Fig. 3.
Further, in this modification, no particular sealing member is provided for the side frame 11 and the upper and lower surface 29 of the side frame 11 are maintained in metal-to-metal contact with the bottom plate 15 and the upper plate 17 of the adjacent beds 12 when the nuts 23 are tightened, thus providing paste sealing members. An auxiliary channel I beam 26 is interposed between the bottom plate 15~and the upper plate 17 in vertical alignment with the I beams and air sealing members 19 respectively between the upper and lower surfaces of the auxiliary channel beam 26 and plates 15 and 17 of the adjacent beds. The space 27 defined by two channel beams 11 and 26 and plates 15 and 17 corres-ponds to the space 25 shown in Fig. 4 and a perforation 24 is formed through the channel melnber 26 for the purpose of communicating the space 27 with a pressure reducin~ means not shown. With this modiied construction, as the volume of the space 27 is large the paste sealing members 29 and the air sealing members 19 are remotely spaced from each other so that there is no fear of contaminating the air sealing members 19 -~ith paste or cement. Moreover, it is possible to readily handle the mould in the same manner as in the previous embodiment.
Figs. 8, 9 and 10 show a different arrangement of the supports 4 and elevating means 5 sui-table for conti-nuously treating the moulds. In this embodiment also the supports 4 and the elevating means 5 are arranged to constitute three point supports, as in the embodiment shown in Fiss. 1 and 2. The moulds shown in Figs. 8 to 10 are constructed as to be transportable. Thus, bars 30 and 31 are connected together to form a T shaped base and sets of support 4 and elevating means 5 are provided for the opposite ends of bar 31 and the righthand end of bar 30.
When such base incorporated with three sets of the support and elevating means is installed on the ground 36, desired moulding operation can be commenced at once. The assembiy can be movèd to any desired place. Different from the embodiment shown in Figs. 1 to 3, in the modification shown in Figs. 8 to 10, while a mould 1 is held on the ground 36 rein~orcing steel bars, aygregate, fittings etc. are fabricated in the mould and then the hydraulic substance is poured into the mould. Then the filled mould is added to the bottom of a stack of filled moulds to be subjected to the required treatments described above. The mould -~ ~
containing a cured or re]easable product is removed from the upper side of the stack. For this purpose, a shaft 32 is mounted on each support 4 for carrying a rotatable member 33 provided with a supporting ledge 34. An elevat-ing means 5 provided with a head 35 is positioned on the inner side of each support 4.
The embodiment shown in Figs. 8 to 10 operates as follows. A mould 1 charged with the hydraulic substance is brought beneath the stack of moulds (only the bed 12 of the 'L0 lowerrn~st mould is shown) which are supported by the supports 4 by me~lls of a conveyor 38, as shown in Fig. 10. The mould is then elevated by the elevating means 5 until the upper surface of the side frame 11 of the mould is caused to abut against the lower surface of the bottom plate of the lower-most b~d l2 of the assembly thus sealing the mould. As the ; newly added rnould 1 is elevated further by the elevating means 5, the assernbly of the moulds is also elevated with the result that the lowermost bed 12 disengages from the supporting ledges 34. Then the rotatable members 33 are rotated to displace the ledges from under the stacked assembly. When the lower surface of the bed 12 of the newly added mould is elevated to the level of the upper surface of - the supporting ledges 34, the ledges 34 are rotated back to the positions shown in Fig. 10 whereby the newly added mould is incorporated into the assembly. At this time, the newly added mould is connected to the bottom of the assembly by suitable connecting means such as the bclts 21 described above. Then the heads 35 of the elevating rneans 5 are lowered to receive the next mould. In this case a crane (not shown) may be used to remove the uppermost mould containing a cured product from the top of the assembly~
In the embodiments shown in Figs. 1 to 3 and Figs. 8 to 10, the moulds are flat and horizontal but the invention in other aspects is not limited to the moulds of such particular configuration. In the embodiment shown in Fig. 11 the side frame 11 of the moulds have arcuate cross-sectional configuration which are supported by the supports 4 and elevating means 5 having the same construction as those shown in Figs. 8 to 10. In this case, each bed 12 is provided with upper plate 17 and bottom plate 15 having curved surfaces 39 and 39a of the radius of curvatures commensu~ate with those of the inner and outer surfaces of the products. Suitable reinforcing members 40 are provided between the upper and bottom plates 39 and 39a of each bed~ Where the upper plate 17 and the bottom plate 15 of adjacent beds 12 are arcuate as shown in Fig.
11, even when a hydraulic substance is moulded in a moulding chamber 57 defined between these plates under a considerably high pressure, these plates will not be deformed. Especially when the opposite ends of the beas 12 interleaved with the moulds are connected together by means of bolts 21 or the like the plates 15 and 17 can resist against considerably high internal pressure without deformation. ~s a conse~uence, where a source of pressure e g- a compressor, not shown, is connected to the load-ing mechanism 54 for loading flowable hydraulic substance into the moulds through a fitting 53, it is possible to apply a considerable high pressure of the order of 5 to 8 Kg/cm2 upon the hydraulic substance poured into the moulds thus increasing the density of the products.

56~

It should be understood that the appa~atus of aspects o~ this invention is not limited to those described above. For example, instead ' of using two types of sealing members, that is the air sealing member and the paste sealing member it is poss~ble to use a single sealing member for sealing against air and paste. Although the connect-ing members shown 1n Figs. 4, 5 and 7 are suitable for adding a new mou1d to one side of the stack of moulds and for removing a mould containing a cured product from the other side of the sta(:k other connecting means can also be used. For example, 0 a plurality of perforations may be formed through respective side frames, and a plurality of moulds may be connected together by means of long bolts which are staggered with one mould height in the vertical direction~ When it is desired to add a new mould or to remove a mould containing a cured or releasable product from the stack one of the bolts is removed. More particularly, when one of the bolts is positioned to project from one side of the stack for making it possible to add the new mould to this side, the mould containing a releasable ~
product can be removed from the other side of the stack. ~ ~;
Q Figs. 12, 13 and 14 show another embodiment in which the side frame comprising a closed mould is constructed to be readily clamped and released.
In the manufacture of various products from a hydraulic substance e.g. cement it is necessary to assemble and disassemble the moulds. Moreover, where a plurality of moulds are stacked as has been described in connection with Figs. 1 through 11, adjacent moulds are connected together by means of a plurality of bolts and ~ ~5~

nuts. The use of plurality of bolts and nuts requires a large labour and time and all nuts are not always tightened - uniformly with the result that a considerable stress will be created in the product due to unequal expansion thereof when it is heat cured, such unequal expansion making it difficult to loosen the nuts.
The embodiment shown in Figs. 12, 13 and 14 was developed to tend to eli~inate such defects. In this embodiment, box shaped beds 12 are disposed on both sides of each side frame 11 and an adjustable operating cylinders 63 are pivotably mounted on one bed by means of pivot pins 7~ secured to the bases of the operating cylinders. The piston rod 65 of each ope~ating cylinder 63 is connected to a piston rod 76 includ-ing a locking head 66 through a turn buckle coupling 75 which is used to adjust the height of the head 66. An anchor plate 77 provided with a notch 67 for receiving the piston rod 76 is secured to the bottom of the other bed 12. By tilting the operating cylinder 63 to the position shown by dot and dash lines in Fig. 13, the head 66 is disengaged from the anchor plate 77. The operating cylinder 63 can be mounted in position by fitting its pivot pins 74 in curved slots 73 in two side plates 72 and then by fastening supporting plates 71 secured to the pins 74 to the side plates 72 by bolts 78.
For the purpose of interconnecting a plurality of side frames 11 of the moulds into a stack, the slots 73 are formed near the upper side of the beds and the anchor plates 77 are welded to the bottoms of the beds as shown in Fig. 13.
~lthough not shown in the drawing suitable pipes may be connected to the beds 12 for introducing into the box shaped beds 12 heating medium, steam for example, for heating and , curing the hydraulic substance poured into the mould. A
plurality of operating cylinders 63 mounted around the periphery of the beds are operated by fluid under pressure like conventional pneumatic or oil pressure cylinders.
After causing the heads 66 to engage the anchor plates 77 the cylinders 63 are operated to pull down the heads 66 against the anchor plates 77. With thi~- arrangement it is possible to simultaneously operate all cylinders by manipulating a single control valve common to all cylinders.
Further it is possible to apply the same or substantially the s`alne clamping force to all clamping heads. The clamping forcc of each head can be independently adjusted during cur-ing by turning the turn buckle coupling 75.
In this embodiment, as the operating cylinder 63 ;
is mounted in position by means of the supporting plates 71, any defective cylinder can be readily removed by dismounting the supporting plates 71. The use of the turn buckle coupl-ing 75 permits not only the adjustment of the height of the locking head 66 but also the exchange of the locking head.
Accordingly, it is possible to use the same opexating cylinder for side frames having different height by adjusting the height of the locking hèad 66 or by exchanging the heads.
Figs. 15 and 16 show a mould utilizing a novel pouring means for pouring the hydraulic substance into the mould which is constructed to close the pouring port after completion of the pouring operation and to facili~ate clean-ing the pouring pipe for enabling repeated use thereof.
The hydraulic substance is generally poured into the mould under pressure or suction. Ho~ever, unless pro-viding suitable means the hydraulic substance poured into - ~5 -3.~.~L5~

the mould often flows back into the pouring tube.
Especially, when concrete or mortar is cast, the concrete or mortar flowed back into the pouring tube solidifies and clogs the same. Even when a check valve is connected in the pouring tube for the purpose of preventing such hack flow, the check valve itself would be rendered inoperative by the solidification of the cement adhering thereto.
Although it is possible to complete the moulding by remain-ing the pouring conditions of the hydraulic substance while in this case the hydraulic substance remaining in the pour-ing tube and cured by the hydration reaction. Thus the substance will solidify in the pouring tube qulckly than in the mould. This requires frequent renewal of the pouring tube or at least to decompose and clean the same, thus greatly decreasing the efficiency of operation.
The pouring means shown in Figs. 15 and 16 is constructed to tend to obviate these difficulties. M~re particular-ly, a pouring tube 83 is connected to a side frame 11 of a mould through a fitting 82. As shown in Fig. 16, the pouring tube 83 takes the form of a letter T and a conduit 93 opening into an intermediate point of the tube 83 is connected to a pouring tank, not shown, for pouring the hydraulic substance into the mould under pressure or static head. A piston 84 is mounted on a piston rod 87 to be slidable in the pouring tube 83. A pipe 85 for admitting cleaning water into the pouring tube 83 is provided and its bifurcated inlet tubes 95 open into the pouring pipe 83 on both sides o~ the conduit 93 and on the opposite sides of the pouring tube 83 as shown in Fig. 16. The piston 84 is operated by fluid pressure. To this end, an operatin~

~ 5~
;

cylinder 86 is connected to one end of the pouring tube 83 and a piston 88 contained in the operating cylinder 86 is connected to the righthand end of the piston rod 87 carry-ing the piston 84 for moving the same between the solid line position and the phantom line position. Instead of providing the operating cylinder 86, it is also possible to operate the piston 84 by means of a manually operated screw mechanism, not shown. Operating fluid is supplied into and exhausted from the cylinder 86 via ports 89 and 90. Thus, the pistons 84 and 88 are advanced by introducing the - operating fluid through port 89 and discharging it through port 90 and vice versa. When the piston 84 is retracted to the phantom position, the hydraulic substance suppliea through the conduit 93 can be poured into the mould. As the piston 84 is moved forwardly by piston 88, the inside of the pouring piston 83 is cleaned. Furthermore when the piston 84 is moved to the solid line position shown in Fig.
15, the inlet port 82 of the side frame 11 of the mould is closed thus terminating the pouring operation. Under these conditions water or other cleaning liquid is introduced into the pouring tube 83 from pipe 85 to remove the hydraulic substance remaining in the pouring tube 83 and the conduit 93. Such cleaning device can be moved from one mould to the other thus saving the labour required for cleaning.
Fig~s. 17 and 18 show a methoa and apparatus suit-able for manufacturing various component parts by a batch process in a field of constructing buildings.
The size and configuration of the component parts required for fabricating buildings vary variously.
In skyscrapers, component parts for the same portions of different floors have different configuration and si~e. Where such component parts are mass produced in a factory and transported to the field of construction, it is not only troublesome but also accompanies the danger of damaging the component parts during transportion hecause of their large weight and size.
Further, the articles of concrete or other hydrau-lic substances are prepared by pouring the hydraulic substance in a mould. However, in order to obtain dense product it is necessary to vibrate the mould after it has been filled with the hydraul:ic substance. To set the mould to withstand against the applied vibration it has been the practice to fix the mould to a bed by means of bolts or other fixing means.
Where a variety of products are to be produced it is neces-sary Lo prepare a number of beds corresponding to the types of the products or moulds thus reducing productivity. More particularly, the factory is required to prepare many types - of moulds and beds.
The invention in its various aspects contemplates the substantial elimination of such defects of the prior art method by sequentially manufactur-ing ine component parts in the field of fabrication thereby enabling smooth fabrication of the building according to a prescribed schedule. This improved method method eliminates the construction of a particular factory~ and makes it possi-ble to transport the coarse aggregate, sand, cement and other raw materials directly to the field of construction. Accord-ingly, it becomes unnecessary to transport products of large weight and variety to the field of construction from the factory. Vibration of the mould which has been imparted to the moulds for compacting the products accompanies noise.

`

But when the hydraulic substance is poured into the mould by reducing the pressure therein it is not necessary to vibrate the mould. Accordingly, the problem of noise does not occur.
Although the apparatus shown in Figs. 1 through 11 are suitable for continuous production, they are bulky and accompany certain inconveniences in operation. The apparatus shown in Figs. 17 and 18 has been simplified for a batch system, which is constructed to construct the component parts for the third and higher floors of the buildings, and to be installed in the building. More particularly, up to the second floors, the building is fabricated according to the prior method and then the apparatus shown in Figs. 17 and 18 is used. Then the workmen can use the portion of the building which has been fabricated as above described as the scalfolding for the assembly of a plurality of moulds and beds. Instead of utilizing the prefabricated portion of the building the apparatus shown in Figs. 17 and 18 can also be installed in a relatively narrow site adjacent the building under construction. As shown in Figs. 17 and 18, two areas or stations E and F are selected for assembling the mould into a stack and areas or yards 121, 122, 123 for collecting ;
the coarse aggregate, fine aggregate and cement, respectively, an area 124 for working reinforcing steel bars, a stockyàrd of the reinforcing steel bars, a mortar mixer 126, a vacuum pump and a vacuum tank 127 and a boiler room 128 are located about the areas E and F. The coarse aggregate, the fine aggregate and cement are transported to their respective yards 121, 122 and 123 by trucks or the like. The steel bars collected in the stockyard 125 are suitably worked in 5~(3 the area 124. The worked reinforcing steel bars are disposed in a side frame 11 of the mould located in the first area A, and then the coarse aggregate 111 is packed in the mould as shown in Fig. 17a. A box shaped bed 12 provided with a bottom plate is mounted on the rnould with an inside mortar sealing member and an outside air sealing member, not shown, interposed therebetween. The mould is sealed from the atmosphere by clamping it between two beds. A plurality of beds and moulds are stacked to form an assembly 110 as shown in Fig. 17b. Depending upon the size of the pro~uct a plurali~ of moulds can be interposed between two beds as shown by the uppermost stage of the assembly shown in Fig.
17b. The moulds of the assembly are then connected to the vacuum tank 127 through a conduit 103 to reduce the pressure in the moulds to 0.1 Kg/cm . When the pressure in the mould is reduced, the beds are urged against the mould by the atmospheric pressure thus effectively sealing the mould. Then the mortar is poured into the mould under the reduced pressure condition. While conduit 103 leading to the vacuum -tank 127 is connected to the mould through an overflow tank 108, the mortar prepared by a mixer 126 is put into an open tank 107 and then poured into the mould through a closed pouring tank 106, a mortar pump 104 and a pouring pipe 105 which is con-nected to the side of the mould opposite to the conduit 103.
In the state shown in Fig. 17b, the lowermost mould has already been poured with mortar and the mould second Erom the bottom of the stack is under pouring. Thus, after con-necting the pouring pipe 105 to this mould, as the valve, not shown, in the pouring tube 105 is opened the mortar can be poured into the mould wh~ch is maintained at a reduced pressure by the pouring pump 104. Although not shown in the drawing the pressure in -the closed pouring tank 106 is reduced by a suitable pressure reducing means so that the entrained air and excessive moisture are removed from the mortar. Thereafter the mortar is poured into the inter-stices~ of the coarse aggregate and into the structure thereof from which air has already been removed by the vacuum tank 122, thereby producing a dense product as in the previous embodiments. Steam is admitted from boiler 128 into the beds :10 12 on the opposite sides of a mould poured with the mortar to heat and cùre the mortar product. Generally, the heat curing is performed at a temperature of from 60 to 85C for acceler-ating the hydration reaction of the poured mortar thereby improving its compression strength in a short time.
Accordingly, it is easy to produce mortar products having a compression strength of more than 180 Kg/cm2 by proper curing operation. Such products are suitable to use as wall panels, floor panels, etc. of buildings immediately after they have been removed from the moulds. Fig. 17b shows one arrangement of releasing the products from the moulds.
Thus, the release can be effected by utilizing an overhead crane 115 running along a rail 115a mounted on a ceiling of a partially fabricated building. The beds 12 and the side frames 11 disassemb~ed in the first area E are transferred to the second area F after cleaning or application of a mould release. In area F different moulds may be used according to the progress of constructing the building.
The same pouring and curing operations~as in area A are also performed in area F. Although in area F, the order of stacking the beds and side frames is opposite to that in area A, the same pouring and curing operations are performed.
Figs. 19, 20 and 21 illustra-te a preferred con-struction or the beds which are used in the arranyement shown in Figs. 17 and 18. While the moulds are constructed to be able to be disassembled, it is advantageous that the beds are of the unitary construction. However, it is diffi-cult to convey large beds to the field of constructing buildings in view of the capacity of trucks utilized to :10 trans~ort the beds.
For this reason, the bed shown in Figs. 19, 20 and 21 is divided into a plurality of units which are assem-bled into a single flat bed, suitable for use in carrylng out the method of this invention. Fig. 19 shows a side view of a stack comprising a plurality of beds and side frames 11 of the moulds and fabricated in either one of the areas E and F shown in Fig. 17. Each bed comprises two identical bed units 12a. Except the divided beds, the stack shown in Fig. 19 is identical to that shown in Fig. 17b.
Fig. 2~ shows the joint between two bed units 12a.
Thus, a reinforcing flange 132 is secured to the lower side of each unit near its end. The reinforcing flange 132 is provided with an opening 133 for loosely receiving a con-necting member, for example a steel rod 134 and positioning members 136 and 136a respectively provided with openings 135a are mounted on the connecting member 134. Screw threads 137 are formed on the peripheries of the positioning members 136 and 136a to receive nuts 138 and 138a located on the opposite sides of the reinforcing flange 132. To compensate for the manufacturing error of the bed the positioning members 136 and 136a are brought into axial alignment by adjusting the nuts 138 and 138a so as to make flush the upper surfaces 139 of the bed units. Furthermore, the positioning members 136 and 136a are formed with members provided with mating inclined surfaces 140 and 140a for assuring the flush relationship of the upper surfaces 139.
Further, beneath one end of one bed unit is provided an air sealing member 142 which is held in position by a holding member 137. When -two bed units are joined together, the other end of the air sealing member i42 is received ~y holdin~ member 141 secured to the end'of the other bed unit thus sealing the interior of the bed against atmosphere.
Fig. 20 shows an enlarged sectional view of the '~
upper i~cs of two bed units 2a which are connected together ~;
and it i`s''to be understood that the lower sides are constructed similarly. In this manner, when bonded together the two bed units form an integral bed having substantially flat upper and lower surfaces which are used as the moulding surfaces wherein the bed units are air tightly joined together.
~0 In the example shown in Fig. 20, the connecting member 134 is shown as a long rod extending to the opposite sides of the assembled bed. However, where the length of the bed is long, for example several meters or more, the connection of two bed units is not sufficiently rigid due to the elongation of long connecting members 134. In such a case some of the connecting members may be made short and nuts 143 (shown by dotted lines) may be threaded on the connecting members 134 for interconnecting the positioning members 13~ and 136a. The use of such short connecting members substantially eliminates the above described trouble caused by ~ s~
the elongation thereof thereby providing a firm bonding. By using both short and long connecting members firm joint can be formed. To turn the nut 143 mating a short connecting member, the bed surface 137 is provided with an opening (not shown) which is normally closed by a cover plate with a sealing member (not shown). The long and short connecting members can be disposed alternately or at different levels.
A hollow tubular air sealing member 145 may be used at the joint between two bed units as shown in Fig. 22. Such sealing member 145 is disposed between holding members 141 and 141a in a deflated condition and the inflated by air. Such tubular air seal member 145 is advantageous be-cause it can be readily exchanged and establishes a good air seal when inflated.
As described above slnce the bed units are provided with position-ing members 136 and 136a at their ends to be joined together, after dis-assembly and transpcrtation to any desired field of constructing buildings it is possible to fabricate the bed units into an integral flat bed by using the connecting members. Moreover, the interior of the assembled bed is efficiently sealed by the sealing member so that the bed can be used to mould the hydraulic substances under reduced pressures. To have a better understanding of the invention the following examples are given.
Example 1 In this example, the apparatus shown in Figs. 1 through 5 was used. Each side frame 11 of the mould had inner dimensions of 2.4 x 5.2 m and a height of 150 mm. In the uppermost mould was poured concrete con-taining 305 K8 Of ~ement per cubic meter of concrete and an excess quantity - 3~ ~

.

.

S5~

of mortar was added to the center of the upper surface of the ce~ent poured into the siae frame 11. The poured side frame was shifted downwardly and a bed 12 was mounted on the side frame and connected thereto by bolts 21. Heating steam was introduced into the beds associated with lower moulds through distxibutor 58 for curing the concrete~
The temperature and the pressure in the moulds were measured at intervals. ~t first the temperature and pressure were normal but increased to 30C and 0.2 Kg/cm2 after 30 minutes, 60C ànd 0.5 Kg/cmZ after 60 minutes, 75C and 0.7 Kg/cm2 after~90 minutes and 102C after 120 minutes. These temper-ature and pressure were maintained during an internal of from 120 to 150 minutes. Thereafter cooling was commenced.
Thus, the steam which has been introduced into the beds 12 was switched to cooling air after 180 minutes. At 210 rinutes when the temperature has decreased to 70C, the air ~as switched to 'cooling water having a temperature of 40C. The temperature of the cooling water was decreased gradually. When the temperature of the product in the lower-most mould has decreased to 40C at 240 minutes, the lowermost mould was separated from the stack and transferred to the releasing station 100 by means of the conveyor 3.
Immediately after releasing from the mould, the product had a compression strength of 125 Kg/cm2 which was increased to 175 Kg/cm2 after one week and to 305 Kg/cm2 after 4 weeks. The dimensional accuracy of the product was also excellent~ Although some air voids remained on the surface of the product, the product is suitable for use as an outside wall of various buildings. ;

s~

Example 2 Apparatus ana mould frames identical to those used in Example 1 were used for manufacturing floor plates.
After fabricating reinforcing steel bars and fittings used for interconnecting adjacent plates in respective moulds according to prescribed designi concrete was poured and cured according to the same process steps as in Example 1.
In this Example for the purpose of eliminating air voids remaining on the surface of the products of Example 1, a plurality of small openings having a diameter of 1 mm were formed through the bottom plate 15 of the bed overlying the side frame 11 and after levelling the upper surface of the concrete poured in the mould, the upper surface of the concrete was covered by a sheet of cloth with its periphery extended to the paste sealing members 18. Then, the bed was placed on the mould with its bottom plate 15 contacted with the cloth. Thereafter, adjacent beds were interconnected by bolts 21. Heat curing was performed in -the same rnanner as in Example 1 and the pressure created in the mould by this heating was effective to drive air entrained in the cast concrete and excessive moisture to the outside of the paste sealing members 18 through said sheet of cloth and small openings. After treatment for 240 minutes, the lower-most mould was transferred to the releasing station 3.
Imrnediately after releasing from the mould the product should a compression strength of 128 Kg/cm2 which was increased to 179 Kg/cm2 after one week There was no air void remaining on thè surface of the product and the dimen-sional accuracy o the surface was +1.5 rnm thus requiring no surface finishing. Thus it was possible to obtain a product having a flat surface by merely coating paint.
The number of workmen required for fabricating the reinforcing stell bars and fittings were 3 and the number of workmen required for performing entire process steps including the treatment of the side frame after re-leasing the products was 7. It is possible to produce 16 floor plates per day each having a dimension of 2.~ x 5.2 m by two cycles of 8 working hours. According to the prior art method and apparatus it was possible to produce the same number of floor plates with 16 workmen. This means that th_ l~slber of workmen was reduced to less than one half.
Example 3 Light weight sheets of rectangular foamea poly- -styrol wcre placed in the mould identical to that used in Examples 1 and 2 at a spacing of 2 cm. Expanded metal sheets were applied to both sides of each light weight sheet. Concrete was then poured in the spaces between the sheets and on both sides of the assembly of the sheets to cover the assembly. In this case concrete was poured in the mould to a level 3 cm lower than the upper edge of the mould. The bottom plate 15 of the bed 12 was not provided with small openings but a sheet of close was placed on the upper surface of the cast concrete. ~fter interconnecting adjacent beds by means of bolts, the interior of the beds was connected to a source of reduced pressure to reduce the pressure in the beds to 0.1 Kg/cm . Under this reduced pressure condition mortar was poured in the space (having a depth of 3 cm) above the cast concrete by using the pressure difference between said reduced pressure and the atmospheric pressure. The reduced pressure is effective to remove the entrained air and exce~sive moisture to the outside of the paste packing members thus producing products of light weight, and having heat insulat-ing and temperature preserving properites and high mechanical strength.
Example 4 In this example the apparatus shown in Figs. 8, 9 and L0 was used. A coarse aggregate consisting of crushed stones ~i~ving a dimension of ~rom 10 to 20 mm was packed in respecti~e moulds which were sealed by assembling into a stack. The pressure inside the moulds was reduced to 0.2 Kg/cm and mortar consisting of 803 Xg/m3 of cement, 803 Kg/m3 of sand and 386 Kg/m of water and having a W/C
ratio c-~6.1 and a flow rate of 20 second was poured into the mol~ld ~y utilizing the pressure difference between said reduced pressure and the atmospheric pressure. The poured concrete was cured unaer the same heating and cooling steps as in Example 1. After the curing treatment for 240 minutes, and immediately after releasing from the mould the proauct showed a compression strength of 120.1 Kg/cm2 which was inc~eased to 170 Kg/cm after 7 days and to 290 Kg/cm after 4 weeks.
Example 5 In this example concrete segments for use in tunnels were prepared by using the apparatus shown in Fig.
1~ and by the process steps described in Example 4. Thus, side frames of the mould were packed with coarse aggregate consisting of crushed stones having a size of 10 to 25 mm and then the moulds were assembled into a stack and sealed.

~L5~

The pressure in the moulds was reduced to 0 2 Kg/cm2 by~eans of a pressure reducing mechanism and then mortar comprising 1,050 Kg of cement, 610 Kg of sand and 440 Kg of water and having a flow rate of 40 seconds was poured into respective moulds by the pressure difference between the reduced pressure and the atmospheric pressure. Then the pressure in the mould was increased to 0.7 Kg/cm2.
Thereafter the cast cement was heat cured in the same manner as in Example 4. Immediately after releasing from the moulds the products had a compression strength of 250O5 Kg/cm2 which was increased to 352 Kg/cm2 after one week and to 505 Kg/cm after 4 weeks. The resulting proaucts are suiiable for use as segments for constructing tunnels or ot7~er civil works.
Exar"ple 6 In this Example, the apparatus shown in Figs. 8 to 10 was used. Light weight concrete consisting of a mix-ture of 600 Kg/m3 of light weight aggregate (produced in the ;
district of Haruna, Japan, and having a speci-fic weight of 0.8 and a grain size of less than 20 mm), 400 Kg/m3 of Portland cement, 540 Q/m3 ~ 100 Kg/m3) of the light wei,ht aggregate having a grain size of less than 1 mm, 160 Kg/m3 of water and 2 Kg/m3 of a foaming agent and having a W/C ratio of 56~ was poured in respective moulds while the pressure in the moulds was reduced to 0.1 Kg/cm2 by the pressure reducing means 45 shown in Fig. 3.
Then steam was admitted into the beds through distributor 58 for heating the cast concrete to 100C
f~r 120 minutes. This temperature was maintained until 180 minutes and then the cured concrete products were cooled to .

5~

72C at 210 minutes and to 42C at 2~0 minutes. The upper-most mould was removed by a crane from the assembly.
Immediately after releasing from the moulds, the concrete products had a compression strength of 80.3 Kg/cm which was increased to 132 Kg/cm2 after 7 days. The surface of the products was smooth and flat in all sides.
Example 7 The same light weight aggregate as in Example 6 was packed in the side frames 11 of the moulds.- Mortar -consisting of the mixture of 70 Kg/m3 of the light aggregate having a grain si~e of less than 1 mm~ 533 Kg/m3 of water, 4.8 Kg/m3 of a dispersing agent, 969 Kg/m3 of ordinary cement and having a W/C ratio of 57% was filled in the intelstices of the prepacked light weight aggregate under atn~:spheric pressure. After assembling the moulds as shown in ,igs. 8 to 10, the moulds were heated to 100C after 120 minutes by steam supplied through the distributor 58. The temperature of 100C was maintained until 190 minutes.
Thereafter the cured concrete products were cooled. When cooled to 43C after 24b minutes, the uppermost mould was removed from the assembly. Immediately after removal from the mould, the concrete product had a compression strength of 60 Kg/cm2 which was increased to 80.5 Kg/cm2 after 7 days.
Example 8 The same light weight aggregate and light weight mortar as in Example 5 were used~ The side frames 11 of the moulds were packed with the light weight aggregate and assembled in a stack as shown in Figs. 8 to 10 with respec-tive moulds closed by the bottom plates of the overlying ,~

o beds 12. The pressure in the moulds was reduced to 0.1 Kg/cm2 by the pressure reducing means 45 for sufficiently removing air in the interstices between the light weight aggregate and in the structure thereof. Then the light mortar was gradually pourea under said reduced pressure for impregnating the mortar in -the interstices of the aggre-gate and in the structure thereof. Thereafter, the pressure in the moulds was increased to atmospheric pressure and then to a pressure of ahout 1 Kg/cm .
The cast mortar was heat cured and cooled in the same manner as in Example 5. When the temperature is decreased to 42C after 240 minutes, the uppermost mould was removed from the assembly. Immediately after removal from the mould, the concrete product had a compression strength of 100 Kg/cm2 which was increased to 150 Kg/cm2.
As has been described hereinabove the invention pro-vides efficient method and apparatus for manufacturing various articles of concrete and other hydraulic substances in a mass production scale having excellent quality.

Claims (87)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method of manufacturing articles made of hydraulic cement comprising the steps of:
preparing a plurality of airtightly closed moulding spaces adapted to be closed in an hermetic manner and having sufficient pressure resistance against the inner pressure therein, which pressure is raised during intro-duction and heat curing of hydraulic cement;
introducing hydraulic cement into said moulding spaces substanti-ally to fill the same by utilizing the pressure difference between the inner side and the outer side of the moulding space;
indirectly heat curing said hydraulic cement from substantially completely around the same immediately after said introduction of the cement is finished, the temperature thereof being rapidly raised up to more than 60°C, and releasing the cured articles from said moulding spaces.

2. The method according to claim 1 wherein said moulding spaces are prepacked with aggregate before the hydraulic cement is introduced thereinto.

3. The method according to claim 2 wherein the pressure in said moulding spaces is reduced, and therein said hydraulic cement is introduced into said moulding spaces under reduced pressure condition.

4. The method according to claim 1 wherein said hydraulic cement is introduced into the moulding spaces by applying pressure on said cement.

5. The method according to claim 1 including the step of insert-ing a formplate in said moulding spaces, thereby to make various pattern products.

6. The method according to claim 1 wherein said hydraulic cement is one or more of cement mixtures, motar, plaster, and calcium silicate.

7. The method according to claim 1 wherein said hydraulic cement is one or more of portland cement, alumina cement, silica cement, blast furnace cement, fly ash cement, high-early-strength cement and slag cement.

8. The method according to claim 1 including the step of disposing at least one of reinforcing steel rods, fittings, members adapted to inter-connect the products, and fibers in the moulding space before said hydraulic cement is introduced thereinto.

9. The method according to claim 1 including the step of disposing means for decreasing the weight of the product in the moulding space before said hydraulic cement is introduced thereinto.

10. The method according to claim 9 wherein said means for decreas-ing the weight of the product comprises a sheet of foamed polystyrol.

11. A method of manufacturing articles made of hydraulic cement comprising the steps of:
preparing a plurality of airtightly closed moulding spaces adapted to be closed in an manner and having sufficient pressure-resistance against the inner pressure therein which is raised during heat curing of said cement;
introducing hydraulic cement into said moulding spaces by utilizing the pressure difference between the inner side and the outer side of the moulding space;
indirectly heat curing said hydraulic cement in said moulding space substantially completely therearound immediately after said introduction of the cement is finished, the temperature being rapidly raised up to more than 60°C, during which the pressure in said space is increased higher than the expansion pressure of the cement; and releasing the cured articles from said moulding spaces.

12. The method according to Claim 11 wherein said hydraulic sub-stance is one or more of cement mixtures, motar, plaster and calcium silicate.

13. The method according to claim 11 wherein said moulding spaces are packed with coarse aggregate before they are poured with said hydraulic substance.

14. The method according to claim 11 including the step of removing a mould containing an article which has been sufficiently cured to a state to be releasable from one side of the stack of said plurality of moulds; and adding an empty mould to the other side of the stack, thus continuously manufacturing the articles.

15. The method according to claim 11 wherein said hydraulic sub-stance is poured substantially simultaneously in all moulds of the stack thus manufacturing the articles by a batch system.

16. The method according to claim 11 including the steps of estab-lishing two stations in a field of fabricating structures, stacking a plural-ity of moulds in one station for manufacturing the articles of the hydraulic substance; disassembling the stacked moulds in said one station and trans-ferring the same to the other station; and stacking the transferred moulds in said other station for manufacturing the articles.

17. The method according to claim 11 wherein said heat curing of the hydraulic substance poured into the moulds is effected by a heating medium admitted into said beds.

18. The method according to claim 17 wherein said heating medium comprises steam or hot water.

19. The method according to claim 11 wherein said hydraulic cement poured into said moulding spaces is heat cured and then is cooled to harden said hydraulic cement.

. . ,

20. The method of claim 11 including the steps of firmly intercon-necting said hollow beds each other for resisting the pressure raised during the introduction and the heat-curing of said cement; and introducing the hydraulic cement into said mould space by utilizing the pressure difference between the inner side and the outer side of the mould.

21. The method according to claim 20 wherein the pressure in the moulding spaces is reduced and wherein the hydraulic cement is introduced into said moulding space under reduced pressure condition.

22. The method according to claim 20 wherein said hydraulic cement is introduced into said moulding spaces by applying the pressure on said cement.

23. A continuous method of sequentially manufacturing articles made of hydraulic cement wherein a plurality of moulds are vertically stacked, said stack having a feed side and a discharge side, each mould including a side frame and a hollow bed with a bottom plate overlying said frame so that said bottom plate of one mould covers said side frame of the next mould, and wherein sealing members are interposed between said beds and the moulds throughout the stack for airtightly closing said moulds, said method con-sisting essentially of: reducing the pressure in the mould at the feed side of said stack; introducing said hydraulic cement into said mould under said reduced pressure condition; introducing a heating medium into said hollow beds surrounding said moulds for gradually heat curing said poured hydraulic cement from the feed side to the discharge side of said stack; advancing each mould by one step at a time through said stack from the feed side to the discharge side thereof, so that each mould occupies the position of the pre-ceding mould as it advances through said stack, the curing of said hydraulic cement taking place at different stages throughout said stack of said moulds;
removing one mould containing an article made of hydraulic cement which has been sufficiently cured from the discharge side of said stack; and preparing a fresh mould at the feed side of the stack where it is recharged with said hydraulic cement, thus continuously manufacturing said articles.

24. A continuous method of sequentially manufacturing articles made of hydraulic cement wherein a plurality of moulds are vertically stacked with a plurality of hollow beds alternately disposed therebetween, said stack having a feed side and a discharge side, said method consisting essen-tially of: reducing the pressure in the mould disposed at the feed side of said stack; introducing hydraulic cement into said mould under said reduced pressure condition; introducing a heating medium into said hollow beds sur-rounding said moulds for gradually heat curing the poured hydraulic cement from the feed side to the discharge side of said stack; advancing each mould and adjacent beds by one step at a time through said stack from the feed side to the discharge side thereof, so that each mould occupies the position of the preceding mould as it advances through said stack, the curing of said hydraulic cement taking place at different stages throughout said stack of said moulds; removing one mould containing an article made of hydraulic cement which has been sufficiently cured from the discharge side of said stack of said plurality of moulds; and preparing a fresh mould and bed at the feed side of said stack where said bed is recharged with said hydraulic cement, thus continuously manufacturing said articles.

25. Apparatus for manufacturing articles of hydraulic cement com-prising: a vertical stack of a plurality of moulds each including a side frame and a hollow bed overlying the side frame; sealing means interposed between said side frames and said beds for hermetically sealing said moulds;
means for releasably interconnecting said stacked moulds; means for reducing the pressure in said moulds; means for pouring the hydraulic cement into said moulds; means for admitting a heating medium into said hollow beds, for indirectly heat curing said hydraulic substance poured into said moulds; and means for releasing said articles from said mould.

26. The apparatus according to claim 25 which further includes:
means for releasably connecting said means for admitting the heating medium into the beds and said means for pouring said hydraulic substance into the moulds to said side frames.

27. The apparatus according to claim 25 wherein the periphery of each hollow bed extends beyond the periphery of each side frame so as substantially uniformly to heat cure the hydraulic substance poured into said side frame by the heating medium admitted into said hollow bed.

28. The apparatus according to claim 25 wherein said sealing means comprises; an inner sealing member for sealing said hydraulic substance poured into the mould; and an outer sealing member for sealing air; and wherein the space between said inner and outer sealing members is connected to a source of reduced pressure.

29. The apparatus according to claim 25 which further comprises:
means for adding an empty mould to one side of said stack; and means for re-moving, from the other side of said stack, a mould containing a cured and releasable article of the hydraulic substance.

30. The apparatus according to claim 25 which further comprises:
supporting means for supporting said stack; and means for elevating said stack.

31. The apparatus according to claim 30 wherein said supporting means supports said stack at more than the spaced points around the peripherv of the mould.

32. The apparatus according to claim 30 wherein said supporting means and said elevating means are mounted on the same bed.

33. The apparatus according to claim 25 wherein each of said hollow beds has arcuate top and bottom plates so as to produce articles having an arcuate cross-sectional configuration.

34. The apparatus according to claim 25 wherein said interconnect-ing means comprises: a cylinder pivotally mounted on one bed; a head supported by the piston rod of a piston contained in said cylinder and adapted to en-gage another bed, said another bed being provided with a notch for receiving said piston rod.

35. The apparatus according to claim 34 wherein said piston rod includes means for varying the length thereof.

36. The apparatus according to claim 34 further including: a pair of transverse pins connected to the opposite sides of said cylinder; a pair of side plates secured to said one bed on the opposite sides of said cylinder, said side plates being provided with curved slots for releasably receiving said pins; a pair of supporting plates respectively connected to the outer ends of said pins; and means for releasably connecting said supporting plates to said side plates.

37. The apparatus according to claim 25 wherein said means for pouring the hydraulic substance comprises: a pouring tube connected to the inlet opening of the side frame; a piston slidably contained in said pouring tube; and means for operating said piston to open and close said inlet open ing.

38. The apparatus according to claim 37 further comprising: a con-duit connected to said pouring tube for supplying thereto the hydraulic sub-stance; and means for supplying cleaning liquid into said pouring tube.

39. The apparatus according to claim 38 wherein said means for sup-plying the cleaning liquid includes: means for supplying said cleaning liquid into said pouring tube from the opposite sides thereof.

40. The apparatus according to claim 25 wherein said stack of the moulds is fabricated in one of a plurality of stations established in the field of constructing a structure, and wherein yards for collecting coarse aggregate, fine aggregate reinforcing steel rods and cement are located about said stations, together with a source of a motar mixture, a source of reduced pressure and a boiler.

.

41. The apparatus according to claim 25 wherein each bed comprises:
a plurality of flat units; and means for interconnecting said units in end-to-end relationship to form an integral wider bed.

42. The apparatus according to claim 41 wherein said units comprise:
positioning members at their ends to be joined; and a sealing member inter-posed between the joined ends; said positioning members being shaped to co-operate each other for making flush the upper surfaces of said unit when they are combined into an integral bed.

43. The apparatus according to claim 42 further comprising: a rein-forcing member including an opening for loosely receiving a positioning mem-ber and provided for one end of each bed unit; means for securing said posi-tioning members to said reinforcing member in correct axial position; and means extending through the openings of the positioning members of both bed units for integrally joining said bed units.

44. The apparatus according to claim 42 wherein said positioning members of both bed units are provided with complementarily inclined surfaces which engage each other for centering the positioning members.

45. The apparatus according to claim 42 wherein said sealing member is retained by a pair of inwardly inclined holding members secured on the in-side of said bed units at the confronting ends thereof.

46. The apparatus according to claim 41 wherein a plurality of said interconnecting members are provided at different levels.

47. The apparatus according to claim 41 wherein said interconnect-ing members comprise: shorter members and longer members; said shorter mem-bers being used to interconnect the positioning members of said bed units; and said longer members having a length to extend over the width of the integral bed, thus clamping togeth er said bed units on their opposite ends.

48. The apparatus according to claim 42 wherein said sealing mem-ber comprises an inflatable tube.

49. The apparatus according to claim 25 which further comprises:
a source of pressure; and means for connecting the interior of said moulds to said source of pressure for applying pressure to the hydraulic substance after it has been poured into said moulds.

50. A method of manufacturing articles of a hydraulic substance, comprising: stacking a plurality of moulds one on top of another, each mould comprising an open-topped mould chamber defined by a side frame mounted on a hollow bed, the bed having a bottom surface which covers the next successive lower chamber to form a closed moulding space, airtight sealing means being interposed between the bed and the next successive lower mould around the said moulding space; filling the moulding space with the hydraulic substance; heat curing the hydraulic substance in each moulding space by admitting a heating medium into the hollow beds between which the moulding space lies; and releasing cured articles from the moulds.

51. A method as claimed in claim 50 wherein the step of filling the moulding space comprises: reducing the pressure in each moulding space and filling the moulding space with the hydraulic substance while the moulding space is under reduced pressure.

52. A method as claimed in claim 50 wherein the hydraulic substance is selected from the group consisting of cement mixtures, mortar, plaster and calcium silicate.

53. A method as claimed in claim 50 wherein each mould is packed with coarse aggregate before it is filled with the hydraulic substance.

54. A method as claimed in claim 50 in which each mould is partially filled with the hydraulic substance before its mould chamber is closed.

55. A method as claimed in claim 50 wherein the moulding spaces are filled in succession and their contents are heat cured in succession.

56. A method as claimed in claim 50 wherein a mould containing an article which has been sufficiently cured to a state to be releasable therefrom is removed from one end of -the stack of the said plurality of moulds; and wherein an empty mould is added to the other end of the stack, this substantially continuosly manufacturing the articles.

57. A method as claimed in claim 50 wherein the plurality of moulds are stacked in one station For manufactured the articles of the hydraulic substance; wherein the stacked moulds in the said one station are disassembled and transferred to another station; and wherein the transferred moulds are again stacked in the said other station for manufacturing further articles.

58. A method as claimed in claim 50 wherein the heating medium comprises steam.

59. A method as claimed in claim 50 wherein the heat cured hydraulic substance is cooled to harden the hydraulic substance before it is released from the mould containing it.

60. A method as claimed in claim 50 wherein at least one element selected from reinforcing steel rods, fittings, members adapted to interconnect the articles, and means for decreasing the weight of the article is mounted in the mould before the mould is filled with the hydraulic substance.

61. A method as claimed in claim 60 wherein the said means for decreasing the weight of the article comprises a sheet of famed polystyrol.

62. Apparatus for manufacturing articles of a hydraulic substance, comprising: a plurality of moulds stacked one on top of another each mould comprising an open-topped mould chamber defined by a side frame mounted on a hollow bed, the bed having a bottom surface which covers the next successive lower mould chamber to form a closed moulding space, airtight sealing means being interposed between each bed and the next successive lower mould around the said moulding space; means for releasably interconnecting the beds; means for supplying the hydraulic substance to the moulding spaces; and inlet means For admitting a heating medium into the hollow beds.

63. Apparatus as claimed in claim 62 wherein the periphery of each hollow bed extends beyond the periphery of each side frame, so as substantially uniformly to heat cure the hydraulic substance poured into said side frame by the heating medium admitted into said hollow bed.

64. Apparatus as claimed in claim 63 including means for reducing the pressure in the moulding spaces.

65. Apparatus as claimed in claim 64 wherein the pressure reducing means is selectively connectible to each moulding space separately.

66. Apparatus as claimed in claims 64 or 65 wherein the said sealing means comprises: an inner sealing member for sealing said hydraulic substance poured into the mould; and an outer sealing member for sealing air; and wherein the space between the said inner and outer sealing members is connected to a source of reduced pressure.

67. Apparatus as claimed in claim 62 which further comprises: at one end of the stack, transport means for adding an empty mould to the said one end of the stack; and, at the other end of the stack, transport means for removing, from the said other end of the stack, a mould containing a cured article of the hydraulic substance.

68. Apparatus as claimed in claim 62 which further comprises: supporting means for supporting the stack; and means for elevating the stack.

69. Apparatus as claimed in claim 68 wherein the supporting means supports the stack at three spaced points around the periphery of the stack.

70. Apparatus as claimed in claims 68 or 69 wherein the supporting means and the elevating means act on the same bed.

71. Apparatus as claimed in claim 62 wherein each one of the hollow beds has arcuate top and bottom plates so as to produce articles having an arcuate cross-sectional configuration

72. Apparatus as claimed in claim 62 wherein the said interconnecting means comprises: a cylinder pivotally mounted on one bed and a head supported by the piston rod of a piston contained in the cylinder; an adjacent bed being provided with a notch for receiving the piston rod upon pivoting of the cylinder.

73. Apparatus as claimed in claim 72 wherein the piston rod includes means for varying the stroke thereof.

74. Apparatus as claimed in claims 72 or 73 further including: a pair of pins connected to the opposite sides of the cylinder and extending transversely of the cylinder; a pair of side plates secured to the said one bed on the opposite sides of the cylinder, the side plates being provided with curved slots for releasably receiving the pins; a pair of supporting plates respectively pivotally connected to the outer ends of the pins; and means for releasably connecting the supporting plates to the side plates.

75. Apparatus as claimed in claim 62 wherein said means for supplying the hydraulic substance comprises: a pouring tube connected to an inlet opening of a said side frame; a piston slidably contained in the pouring tube; and means for operating the piston to open and close the inlet opening.

76. Apparatus as claimed in claim 75 further comprising:
a conduit connected to the pouring tube for supplying thereto the hydraulic substance; and means for supplying cleaning liquid to the pouring tube.

77. Apparatus as claimed in claim 76 wherein the said means for supplying the cleaning liquid supplies cleaning liquid to the pouring tube at more than one position.

78. Apparatus as claimed in claim 62 wherein the stack of the moulds is fabricated in a construction site, and wherein yards for collecting coarse aggregate, fine aggregate, reinforcing steel rods and cement are located about the site, together with a mortar mixer and a boiler.

79. Apparatus as claimed in claim 62 wherein each bed comprises a plurality of units; and including means for interconnecting the units in end to end relationship to form the bed.

80. Apparatus as claimed in claim 79 wherein the units comprise: positioning members at their ends to be joined;
and a sealing member interposed between the joined ends; and wherein the positioning members are shaped to cooperate with each other for making flush the upper surfaces of the units.

81. Apparatus as claimed in claim 80 wherein the positioning members pass through openings in reinforcing members at the said ends of the units; wherein means are provided for securing the positioning members to the reinforcing members;
and wherein the positioning members have openings receiving a connecting member for integrally joining the units.

82. Apparatus as claimed in claims 80 and 81 wherein the positioning members of adjacent units are provided with complementarily inclined surfaces which engage each other for centering the positioning members.

83. Apparatus as claimed in claims 79, 80 or 81 wherein the sealing member is retained by a pair of inwardly inclined holding members secured on the inside of the units at the confronting ends thereof.

84. Apparatus as claimed in claims 79, 80 or 81 wherein the said sealing member comprises an inflatable tube.

85. Apparatus as claimed in claims 79, 80 or 81 wherein each bed has a plurality of the said interconnecting means.

86. Apparatus as claimed in claims 79, 80 or 81 wherein each bed has a plurality of the said interconnecting means and wherein the said interconnecting means comprises shorter connecting members interconnecting adjacent ends of adjacent bed units and longer connecting members interconnecting remote ends of the bed units at opposite sides of the bed.

87. Apparatus as claimed in claim 62 which further comprises: a source of pressure, and means for connecting each moulding space to the source of pressure for applying pressure to the hydraulic substance after the mould space has been filled.