GB2115769A - Strapping a batch of products - Google Patents

Abstract

A method and apparatus for strapping together a batch of products, typically cast concrete building blocks 2a, the apparatus is mounted on a wheeled chassis 1 which moves over the blocks and compacts a batch of blocks by jaws operating in directions 4 and 5 before lifting the batch by means of the jaws and applying a binding strap around the sides of the batch. <IMAGE>

Description

SPECIFICATION Strapping a batch of products The present invention relates to the strapping of a batch of products which are standing adjacent each other. The invention is particulariy suitable in strapping together a batch of cast concrete building blocks.

Concrete building blocks may be cast in batches in an open yard. A wheeled casting machine may be used which casts at once a batch of, for example, 4 x 12 blocks. When the blocks have been cast, the machine moves on to cast another batch adjacent the first batch and so on.

The resulting line of batches may be one hundred or more metres long. Many lines may be cast next to each other.

Once the blocks have cured, which may take anything from one to seven days depending on the weather, the blocks in a batch are usually strapped together. Where small batches are cast at once, a number of batches may be strapped together.

Conventionally the strapping has been done manually. An operator places a strap around the batch and operates a manual strap securing tool to tension and secure the strap.

After casting, the blocks stand adjacent each other slightly spaced apart. The manual application of a strap may tilt the blocks but is generally not sufficient to draw them bodily together to make a tight pack. Therefore, not only is the manual system difficult and timeconsuming, but it produces packs which are often not secure. The present invention seeks to provide an improvement.

According to one aspect of the invention there is provided a method of strapping together a set of products which are standing adjacent each other in a rectangular batch, the method consisting in engaging opposite sides of the batch with jaws and urging the jaws together so as to compact the products, in the two dimensions of the rectangle, and binding the batch by means of a binding strap applied around the sides of the compacted batch by means of a strapping mechanism.

According to another aspect of the invention there is provided apparatus for strapping together a set of products which are standing adjacent each other in a rectangular batch, the apparatus comprising jaws for engaging opposite sides of the batch and means for urging the jaws together so as to compact the products, the apparatus being capable of compacting the batch in both dimensions of the rectangle, and a strapping mechanism which applies a binding strap around the sides of the compacted batch.

In some situations it may be possible to use a single pair of jaws to compact the batch first in one dimension and then by turning and reapplying the jaws, in the other dimension. However, preferably there are two pairs of jaws arranged at right angles to each other for compacting the batch perhaps simultaneously in the two dimensions but preferably in one dimension and then in the other.

Preferably, both pairs of jaws are mounted in a single framework, which may be lifted as explained below. However, each pair of jaws may have its own framework, one of which may be the chassis mentioned below, in which case the framework for the other pair of jaws may be lifted.

Whilst it is envisaged that the strapping means may be lowered to a suitable strapping position, it is preferred that the products be lifted up for strapping. They may be lifted whilst held by one or other of the pairs of jaws. For lifting, this pair of jaws may be mounted for vertical movement in the framework and a lifting actuator be provided.

Alternatively the framework itself may be raised, bringing up the jaws and the blocks with it.

The strapping means preferably comprises a strapping head of known design in combination with a rectangular chute and flaps into which the compacted batch of products is lifted. In operation the strap is fed around the chute, then tensioned and secured.

Where the products are concrete blocks or other cement products, the framework is preferably mounted in a powered and wheeled chassis for movement along a line of sets of blocks. Once each batch has been strapped, it may be lowered onto the casting surface in its original position. Alternatively the apparatus may be controlled to stack batches on top of each other.

The control of the apparatus may be automatic, even to the extent that the apparatus may be set in operation at one end of a line of batches and left to move along the line pressing together and strapping each batch.

The invention will be described with reference to the accompanying drawings of which: Figure 1 is a schematic plan view of apparatus according to the invention in use for compacting and strapping batches of concrete building blocks; Figure 2 is a more detailed plan view of the apparatus of Figure 1; Figure 3 is a side elevation of the apparatus; and Figure 4 is an end elevation of the apparatus.

Referring to Figure 1 the illustrated apparatus is a wheel-mounted compacting and strapping machine 1. Concrete building blocks are cast in rectangular batches 2 of, in this example, 4 x 9 blocks. The casting machine (not shown) runs along a track and casts batches at spaced intervals. The blocks are left to stand until cured.

There are slight gaps between the blocks of each batch.

The machine 1 runs along the line and stops at each batch to effect firstly compacting of the blocks together and secondly strapping of blocks with a binding strap. The machine is shown in position over a batch of blocks, having compacted and strapped a batch 2a. The next batch to be compacted and strapped is shown at 2b.

Compacting is effected by two sets of jaws which, as illustrated in the Figure, firstly press together the blocks in one dimension of the rectangle as illustrated by the arrows 4; and secondly press together the blocks in the other dimension of the rectangle as illustrated by arrows 5. The compacted batch of blocks is then lifted by the jaws to a position where a strapping head (to be described) may pass a strap around the sides of the batch and bind the batch together. The batch is then dropped back in position and the machine moves on to the next batch.

Referring now to Figures 2 to 4 the machine is shown in greater detail. The machine comprises a main frame 6 which supports a strapping frame 7.

The strapping frame supports a strapping head, and a strap reel 9. A clamping frame 10 is movably supported on the main frame and carries two sets of jaws 11 and 12. Each set of jaws comprises a pair of parallel bars which are capable of being urged together by hydraulic rams 13. The machine normally travels with the clamping frame raised to a position illustrated in broken line (see particularly Figure 4). When over the batch of blocks the clamping frame is lowered under control of lift cylinders 14 and the jaws are thus positioned towards the bottom of the batch of blocks. The hydraulic rams 1 3 are operated in turn to press the blocks together in the two dimensions of the rectangle. Then, with the blocks held by the jaws 11 and 12, the clamping frame is raised to a position wherethe strapping head may feed a binding strap around the sides of the compacted batch of blocks. The strapping head passes around a chute 15 surrounding the blocks and thus draws a length of steel strap around the blocks, the strap being supplied from reel 9. The strapping head frame 7 is movably mounted on the main frame and is indexed by a hydraulic cylinder 1 6 each time a strapping operation is performed.

Claims (10)

1. A method of strapping together a set of products which are standing adjacent each other in a rectangular batch, the method consisting in engaging opposite sides of the batch with jaws and urging the jaws together so as to compact the products, in the two dimensions of the rectangle, and binding the batch by means of a binding strap applied around the sides of the compacted batch by means of a strapping mechanism.

2. The method as claimed in claim 1 wherein the products are cast concrete building blocks.

3. The method as claimed in claim 1 or claim 2 wherein the products are lifted by the jaws for the strapping operation.

4. Apparatus for performing the method of claim 1 and comprising jaws for engaging opposite sides of the batch and means for urging the jaws together so as to compact the products, the apparatus being capable of compacting the batch in both dimensions of the rectangle, and a strapping mechanism which applies a binding strap around the sides of the compacted batch.

5. Apparatus as claimed in claim 4 wherein there are two pairs of jaws arranged at right angles to each other for compacting the batch in the two dimensions.

6. Apparatus as claimed in claim 5 wherein the two pairs of jaws are mounted in a single framework, and means are provided for lifting the framework, and thus the jaws and any products held thereby.

7. Apparatus as claimed in any of claims 4 to 6 for strapping together sets of cast concrete building blocks, the apparatus comprising a powered and wheeled chassis for movement along a line of sets of blocks.

8. Apparatus as claimed in claim 7 and including means for lifting and stacking strapped sets of blocks on top of each other.

9. A method of strapping together a set of products substantially as hereinbefore described.

10. Apparatus for strapping together a set of products substantially as hereinbefore described with reference to the accompanying drawings.