GB2122127A

GB2122127A - Method and apparatus for the manufacture of blocks

Info

Publication number: GB2122127A
Application number: GB08217615A
Authority: GB
Inventors: P R G Smith; R W Smith
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-06-17
Filing date: 1982-06-17
Publication date: 1984-01-11

Abstract

In a method and apparatus for the manufacture of hollow, preferably of concrete, a mould box 3 having a removable centre core 8 is placed on a vibratable bottom plate of a press and includes removable support rods which support reinforcement bars extending parallel to the walls of the box. The box is filled with a mix preferably concrete, vibrated to settle the mix, the support rods removed and the mix compacted following which the mould box and centre core are removed and the block cured. <IMAGE>

Description

SPECIFICATION Method and apparatus for the manufacture of concrete blocks The present invention relates to a method and apparatus for the manufacture of concrete blocks, especially hollow blocks, that require the inclusion of reinforcing elements.

It is known to manufacture concrete blocks by an automatic process in which a mould is filled with a predetermined volume of concrete mix; subject to a primary vibration to distribute the mix and then compressed by the action of a pressure head applied to the mix with secondary vibration in order to achieve the desired degree of compaction. During the compression step the volume of the mix may be reduced by as much as 2530%.

This method does not, however, allow for theinsertion of reinforcing elements. Thus in the manufacture of hollow concrete sections used, for example in a manhole chamber, the compression step has to be carried out manually and as a result the blocks are produced relatively slowly and are not as strong in view of the more limited degree of compression that can be obtained. In the manual process the mould is filled with a suitable mix, the reinforcing elements then laid within the mould which is then completely filled with mix which is then subjected to manual compression.

We have now modified the automatic process enabling the introduction of reinforcing elements into the block to be achieved without interrupting the manufacturing process. In order to achieve this result the mould has been modified to allow at least 2 removable supporting members to be inserted at the required height above the base of the mould and to extend parallel thereto and preferably completely across the mould section.

The reinforcing elements that are required to be included in the block may then be placed on the supporting members before the mix is introduced.

After the mix has been introduced and subjected to a primary vibration to achieve uniform distribution, the support members are removed and the mix machine compressed with secondary vibration by the usual method. After compression the block is removed from the mould and cured for example by standing at ambient temperature or by heating.

For the purpose of the present invention the term "concrete" is to be considered as including a mix of an aggregate, for example crushed stone or ash, bonded by a curable binder, usually cement although a suitable resin might be used.

One embodiment of the invention will now be described with reference to the accompanying drawings in which: Figure 1 is an exploded diagrammatic representation of a section through an apparatus suitable for use in the present invention.

Figure 2 is a diagrammatic representation of the apparatus of figure 1 at the end of a compression step; Figure 3 is an end elevation through a manhole chamber section made according to the invention.

The apparatus of figures 1 and 2 is used between the plates of a press (only one of which plates is shown) which press has the facility for imparting a vibratory motion to the lower plate.

The apparatus shown in figure 1 includes a rectangular pallet 1 on which is placed a rectangular lower mould member 2, including a downwardly extending grooved portion 20 formed parallel to each side thereof; an outer hollow mould box 3 containing two pairs of holes 4 and 4 to receive reinforcement support bars 30, only one pair of such holes and one support bar being illustrated, recesses 6 and 7 are formed in the top of the mould to receive the supporting lugs 9 and 10 of a centre core 8; and a rectangular upper mould 12 of the same dimensions and shape as the bottom mould 2 permanently attached to the upper press plate 11 of a press (not shown).

In use the pallet 1 is first positioned on the block making machine, the outer mould box 3 mechanically placed on the pallet and the bottom mould 2 introduced into the mould box 3 to rest on the pallet 1. The reinforcement support members 30 are then inserted through holes 4 and 5 and reinforcing steel elements (not shown) placed across the support members. The centre core 8 is then introduced into the hollow mould box 3, lugs 9 and 10 engaging in respective slots 6 and 7 formed in the top of the box. A predetermined amount of a semi dry concrete mix, consisting to crushed stone, sand, cement and the appropriate amount of water, is then automatically introduced into the area of the mould between the outer member 3 and the inner core 8.The assembly is then subjected to a primary vibration through the lower plate of the press in order to distribute the concrete mix evenly within the mould. After the vibration has been completed the reinforcing support members 30 are withdrawn and the mix compacted by applying pressure through the top mould 1 2 attached to the upper pressure plate 11, at the same time the mould is subjected to a secondary vibration. After an adequate degree of compaction has been achieved by the application of a predetermined maximum pressure for a given period of time, the pressing head is vertically withdrawn, followed by the mould box and centre core leaving the uncured section and bottom mould on the pallet. The pallet together with bottom mould and uncured section is then removed and transported to a kiln for steam curing.

Figure 3 illustrates an end elevation through a finished manhole chamber section 40. The section comprises side walls 41, 42 with corresponding front and rear walls in which are located a single rectangular reinforcing member 43. Grooves 44 are formed in the upper frame of the wall members and the lower face includes a downwardly extending member 45 having a shape complimentary to grooves 44 in order to enable sections to be stacked one on top of the other.

Claims

1. A method for the manufacture of a reinforced concrete block in an apparatus including a bottom mould and a mould box, wherein said mould box includes at least two removabie, inwardly projecting support members, said method comprising; laying reinforcing elements across said support members, introducing a flowable concrete mix into said mould, subjecting the mould and the mix to a primary vibration, removing the support members, compacting the mix to a predetermined maximum pressure whilst subjecting the mould and mix to a secondary vibration, removing the mould box from the compacted mix block and curing at a predetermined temperature and for a predetermined minimum time to form a solid reinforced concrete block.

2. A method according to claim 1 wherein the mould includes a centre core for the production of a hollow block, said core being removed with the said mould after compaction.

3. A method according to claim 1 or claim 2 wherein the mix is compacted through the action of a pressing head acting against a top mould positioned on the top of the said mix.

4. A method according to claim 3 wherein the top mould and the bottom mould include complimentary recesses extending thereacross, wherein complimentary projections and grooves are formed in the top and bottom surfaces of the resultant blocks to enable two or more said blocks to be stacked.

5. A method for the manufacture of a reinforced concrete manhole section according to the process as claimed in claim 3 or 4 as dependent upon claim 2.

6. A process for the manufacture of a reinforced concrete block substantially as hereinbefore described.

7. Apparatus for the manufacture of reinforced concrete blocks including a bottom mould, a mould box, means for vibrating the mould box and means for compacting a concrete mix in said mould box, wherein the said mould box includes at least two removable, inwardly projecting members capable of supporting reinforcing elements prior to the introduction of a concrete mix into the said mould box.

8. Apparatus according to claim 7 wherein the said support members extend across the width or length of the said mould box and are aligned parallel to the bottom mould.

9. Apparatus according to claim 7 or claim 8 wherein the mould box contains a removable centre core and the said support members are positioned between the walls of the box and the centre core.

10. Apparatus according to claim 9 wherein the said members support reinforcing elements positioned parallel to the walls of the mould box.

11. Apparatus according to any one of claims 7-10 wherein the means for compacting the mix comprises a press having upper and lower press plates, the mould box being positioned on the lower press plate and the upper press plate acting against a top mould.

12. An apparatus according to claim 11 wherein the press includes means for vibrating the lower press plate.

1 3. Apparatus for the manufacture of reinforced concrete blocks substantially as hereinbefore described with reference to figures 1 and 2 of the drawings.