GB2186231A - Machining building blocks - Google Patents

Abstract

Apparatus for the cutting of building blocks (3), in particular "formwork blocks", is provided with a conveying device (1) to feed the blocks, a first machining station (4) at which grooving cutters (5) cut longitudinal grooves in one side of the blocks, and a second machining station (8) at which further cutters (10) cut the side of the block opposite the longitudinal grooves. Above the first machining station (4) is mounted a conveyor device (13) for the blocks (3), with conveyor links (12) aligned with the tops of the blocks. The second machining station (8) is provided with rail-type guides (17) on which the block is guided. The guide rails (17) extend from the rear of the grooving cutters (5) and continue up to the second machining station (8), and there reach substantially to a point below the second cutters (10), with the blocks (3) for machining being guided along the guide rails (17) by their cut grooves. <IMAGE>

Description

SPECIFICATION Apparatus for cutting building blocks The invention relates to apparatus for the cutting of building blocks, in particular "formwork blocks".

A high degree of dimensional accuracy is required especially for "formwork blocks", which are laid on top of one another without mortar, and only later joined together to form a solid wall by means of concrete filling their hollow interior. The same applies to blocks used for building walls by bonding.

It is not possible to achieve the necessary dimensional accuracy with known machines for the manufacture of blocks. This means that blocks used in the processes referred to must be cut to the required degree of accuracy by means of a milling cutter.

To this end, a device for the cutting of building blocks, in which the top and bottom of a block are cut in sequence to the required degree of accuracy, at milling stations, is already known, having an accelerator and a turnover unit between the two milling stations, and is thus a relatively expensive design.

Moreover, this device is of only limited suitability for cutting "formwork blocks" to a high degree of accuracy.

The present invention is therefore based on the problem of creating an apparatus of relatively simple design for machining building blocks to a high degree of dimensional accuracy.

According to the invention there is provided apparatus for the cutting of building blocks, the apparatus comprising conveying means for feeding blocks, a first machining station at which groove cutting means are arranged to cut longitudinal grooves in one side of each block, and a second machining station at which further cutting means are arranged to cut the opposed side of the block, conveyor means for the building blocks being mounted above the first machining station for operative engagement with the blocks, and guide rails extending from the groove cutting means along the extended cutting planes thereof to the second machining station to substantially below the further cutting means, whereby the blocks for machining can be guided along the guide rails by their cut grooves.

The arrangement of the conveyor means above the first machining station ensures careful movement of the building blocks. In contrast to movement of the blocks by pushing, through an upstream conveyor unit catering exclusively for forward feed, the blocks for machining are now drawn through the first machining station, and are also fed in the same manner to the second machining station by means of intermediate moving links. With movement purely by pushing or by pressure from following blocks, there is a danger of blocks being broken, especially if they are not precisely aligned or are running askew.

The guide rails make it possible to achieve very precise guidance, and thus very precise cutting at the second machining station, where the exact height of the building block is determined. Because of the fact that, immediately after the first cutting operation, the blocks are guided along the guide rails by their cut grooves, it is possible not only to achieve precise movement with lateral guidance, but also to ensure an exact height. To this end it is necessary only to ensure that the depth of the groove and the rail height are so aligned that the block rests on the rails only at the grooves and otherwise passes freely through the machining station.

Naturally, if required, the rail-type guides can be so designed as to be powered. One possible form is that of an endless chain conveyor.

It can also be advantageous to move the building blocks along similar guide rails over the feed section to the first machining station, up to the groove cutting means; here the guide rails are arranged on both sides, but inside or outside the two grooving cutters. For secure support, it is beneficiai if these first guide rails are allowed to extend at least approximately to the area of the rotational axes of the grooving cutters or just beyond. The greater the transverse distance between the two opposing guide rails, the better and safer will be the support, thus avoiding tilting and/or rocking of the blocks.

But of course it is possible to provide other guide elements for the building blocks in this section ahead of the grooving cutters.

It is easy to arrange for the conveying means upstream of the first machining station to have powered roller conveyors. Since an additional feed is provided in the vicinity of the first machining station, this simple type of drive is adequate.

To match different kinds of work and different cutter qualities, it is advantageous to provide the drive unit for the conveyor means over the first machining station with an adjustable speed or even a reversing facility. For this purpose, e.g. an adjustable speed motor or a variable speed gearbox can be used.

The conveyor links of the conveyor means may be of any desired type. The only important factor is that they ensure adequate movement of the building blocks to be machined.

For this purpose, a simple solution is for example to provide pressure rollers, which are pressed against the tops of the blocks for machining.

To increase feed force, the pressure rollers may be provided with ribs, cams, knobs and the like around their circumference. An identical effect can also be achieved by the use of an adhesive surface on the pressure rollers.

An embodiment of the present invention will now be described by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a schematic side view of the apparatus described in the invention; Fig. 2 is an enlarged partial top view of the first machining station; Fig. 3 is an end view of the apparatus described in the invention, from the direction of arrow A in Fig. 1; and Fig. 4 is a reduced illustration of "formwork blocks" laid on top of one another.

A device for cutting building blocks has a conveyor device 1 with a number of roller conveyors arranged in sequence, on which the building blocks 3 for machining are conveyed.

The roller conveyors 2 may be driven as desired.

In the example, a "formwork block" has been chosen as the type of building block 3 to be machined. But of course the cutting device according to the invention, with suitable modification and mounting of cutters, can also be used to cut the top and bottom faces of other building blocks, e.g. hollow blocks.

The conveyor device 1 is followed by a first machining station 4 with two side-mounted grooving cutters 5. The two grooving cutters 5 may be driven in any way desired. In general, a common cutter shaft 6 is provided for this purpose. The cutter shaft 6 can be mounted in a machine frame 7 and driven as desired. The machine frame may be open or enclosed at the top.

The first machining station 4 is followed by a second machining station 8 with cutters 10 mounted in an assembly 9. The two cutters 10 are likewise driven as desired and have a common cutter shaft 11. Also mounted in or at the assembly 9 are several pressure rollers 12 serving as the conveying links of a conveying device 13. The pressure rollers may also be mounted as desired and exert on the blocks 3 to be machined not only a feed force but also a downwards force which counteracts the force generated by the cutting process.

In the vicinity of the first machining station 4, at the side and commencing at the feed section 14, two guide rails 15 are provided, as an extension of the roller conveyors 2. The feed force generated by the pressure rollers 12 pushes the building blocks 3 to be machined, forward along the guide rails 1 5 towards the two side-mounted grooving cutters 5.

As soon as the building blocks 3 reach the area of the rotating grooving cutters 5, a groove 16 is cut in each side of their bottom face (see Fig. 3).

Immediately after the cutting process, i.e.

after introduction of the two longitudinal grooves 16 in the building block 3, the latter is moved by further forward pressure from the pressure rollers 12 on to two further guide rails 17. As can be seen from Fig. 2, the two guide rails 17 lie in the extended axis of the two grooving cutters 5 and of the cutting plane 21, so that as they advance, the building blocks 3 can run precisely along the guide rails on their freshly-cut grooves 16.

As Fig. 2 shows, the two guide rails 15 extend in the direction of the second machining station 8 over the axis of rotation and cutter shaft 6, thus permitting a trouble-free transition of the blocks to the succeeding guide rails 17.

In this way-with the guide rails 17 at an appropriate height-precise guidance is obtained during the further advance of the blocks 3. This applies both to lateral guidance, which prevents the blocks from running askew, and to an exact height of the blocks 3. Since the two cutters 10 of the following second machining station 8 also have an exact height position, this means that the blocks can be cut to a precise height and also with parallel top and bottom faces, with the groove depths and the associated opposing web heights being kept at exactly uniform dimensions. Building blocks 3 of this kind can be used to build a very neat wall, as is seen especially clearly from Fig. 3. Thus, when the blocks are laid on top of one another, they fit together with their longitudinal grooves 16 and their accurately cut projections or webs 18 on the opposite sides (Fig. 4).

If required, to increase the feed force, the pressure rollers can be provided with an adhesive covering (not shown) or with ribs, cams, knobs or the like. For reasons of clarity, only one pressure roller 12 is provided with knobs 19 of this kind in Fig. 1.

To match different kinds of work and/or different cutter qualities, the conveyor device 13 can be provided with an adjustable speed drive unit 20. Since drive units of this kind are generally known, they are not described in detail here. If required, the drive unit can also be designed so as to be reversible.

Claims (11)

1. Apparatus for the cutting of building blocks, the apparatus comprising conveying means for feeding blocks, a first machining station at which groove cutting means are arranged to cut longitudinal grooves in one side of each block, and a second machining station at which further cutting means are arranged to cut the opposed side of the block, conveyor means for the building blocks being mounted above the first machining station for operative engagement with the blocks, and guide rails extending from the groove cutting means along the extended cutting planes thereof to the second machining station to substantially below the further cutting means, whereby the blocks for machining can be guided along the guide rails by their cut grooves.

2. Apparatus according to claim 1, wherein the guide rails commence at a location directly after the groove cutting means.

3. Apparatus according to claim 1 or 2, wherein, in a feed section of the first machining station, guide rails are provided between a pair of groove cutters of the groove cutting means, with the guide rails extending substantially to the axis of rotation of the groove cutters.

4. Apparatus according to claim 3, wherein the guide rails of the first machining station extend to a limited extent beyond the axis of rotation of the groove cutters in the direction of the second machining station.

5. Apparatus according to any of the preceding claims, wherein the conveying means has powered roller conveyors.

6. Apparatus according to any of the preceding claims, wherein the conveyor means above the first machining station has an adjustable speed motor or a variable speed gearbox.

7. Apparatus according to any of the preceding claims, wherein conveyor links of the conveyor means have pressure rollers, which are pressed against said one side of the building blocks to be machined.

8. Apparatus according to claim 7, wherein the pressure rollers are provided with ribs, cams, knobs or the like on their circumference.

9. Apparatus according to claim 7, wherein the pressure rollers have an adhesive covering.

10. Apparatus for the cutting of building blocks, substantially as hereinbefore described with reference to the accompanying drawing.

11. Any novel subject matter or combination including novel subject matter herein disclosed in the foregoing Specification or Claims and/or shown in the drawings, whether or not within the scope of or relating to the same invention as any of the preceding claims.