Concrete piles are normally reinforced with a substantially cylindrical cage of steel reinforcing bars made up from a ring of vertical bars that are interconnected by a set of horizontal wire hoops that are wrapped around the ring of vertical bars and connected to those bars either by welding or by means of wire ties. Alternatively, instead of separate hoops, a wire may be wrapped helically around the vertical bars. Helical cages are generally preferred, as they are stronger and less prone to collapse, and they require less wire since there are fewer overlaps.

Reinforcing cages have traditionally been constructed entirely by hand. The vertical bars and the hoops are positioned manually and they are then connected together by welding or tying the joints. In the case a helical cage, a skeleton cage may be constructed first using a few hoops and lengths of wire may then be wrapped helically around the skeleton cage and attached to it, again by welding or tying. Constructing a helical reinforcing cage is a very labourious process that may take many man hours.

It is an object of the present invention to provide a cage making machine and a cage making method that mitigate at least some of the aforesaid disadvantages and simplifies the cage making process.

According to the present invention there is provided a cage making machine for making reinforcing cages, said cage making machine including a setting up bed for use in a first assembly process for assembling a skeleton cage, a winding bed for use in a second assembly process for winding wire onto the skeleton cage, and a wire delivery device for delivering wire to the winding bed during the second assembly process, said setting up bed including a first set of looped, flexible support members for supporting a skeleton cage during the assembly thereof, said looped, flexible support members each having a plurality of spacing elements for setting the relative separations of a plurality of parallel bars forming vertical components of the skeleton cage, and a drive system for driving said looped, flexible support members to cause rotation of the skeleton cage about its longitudinal axis

during the assembly thereof, said winding bed including a second set of looped, flexible support members for supporting the completed skeleton cage, and a drive system for driving said second set of looped, flexible support members to cause rotation of the skeleton cage about its longitudinal axis, said wire delivery device including a guide device for guiding the delivery of wire to the winding bed during the second assembly process and a drive system for driving said wire delivery device so that it moves along the length of the winding bed as the skeleton cage rotates, whereby the wire delivered to the winding bed is wound helically around the skeleton cage.

According to a further aspect of the present invention there is provided a method of making a reinforcing cage using a cage making machine as described in the preceding paragraph.

The machine and the method may be used for making welded or non-welded pile cages.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1A is an end view of a first part of the cage making machine; Figure 1B is an end view of a second part of the cage making machine; Figure 2 is a plan view of the first part of the cage making machine; Figure 3 is a plan view of the second part of the cage making machine; Figure 4 is an end view of a trolley forming part of the cage making machine; Figure 5 is a schematic end view showing the arrangement for making cages of different diameters; Figure 6 is a schematic perspective view of a skeleton cage made using the machine.

Figure 7 is a schematic perspective view of a partially completed cage made using the machine, Figure 8 is a plan view showing the general layout of an optional feeder system.

Figure 9 is a plan view a feeder arm assembly forming part of the feeder system:

Figure 10 is a side view of the feeder arm assembly ; Figure 11 is a rear view of the feeder arm assembly; Figure 12 is a side view of a reinforcing cage having a helical reinforcing wire of uniform pitch, and Figure 13 is a side view of a reinforcing cage having a helical reinforcing wire with a variable pitch.

A cage making machine according to the invention is shown in the drawings and includes a table 2 that carries a supply of steel reinforcing bars 4, a setting up bed 6 for setting up and constructing a skeleton cage 8, a winding bed 10 for winding a helical wire onto the skeleton cage, a wheeled trolley 12 carrying a reel 14 of reinforcing wire 15 and an offloading ramp 16 for removing a completed cage 18 from the machine.

The table 2 consists of a framework having a substantially horizontal upper surface 20 for supporting a supply of steel reinforcing bars 4, which is defined by a plurality of parallel beams 22 and supported by a set of legs 24 and braces 26. At the rear edge of the upper surface 20 and upstanding backstop 28 is provided while at the front edge of that surface 20 a plurality of pivoting arms 30 are connected to the beams 22.

The setting up bed 6 is spaced a short distance from the table 2 to provided a gap 32 down which an operator can walk while operating the machine. The pivoting arms 30 substantially bridge this gap when rotated clockwise from the position shown in Fig. 1A through an angle greater than approximately 120 °, allowing bars 4 to be transferred easily from the table 2 to the setting up bed 6.

The setting up bed 6 includes a support framework 34 that supports a plurality of looped chains 36, which are spaced at regular intervals along the length of the framework. A plurality of spacing elements (e. g. pins or studs) 38 are attached to the links of the chains and extend radially outwards from those chains to serve as locating elements for the bars 4 when they are transferred onto the setting up bed 6.

Each chain 36 is supported on two free-running sprockets 40. 42 and a drive sprocket 44.

The drive sprockets 44 are interconnected by a drive shaft 46, which is driven via a belt 48

by an electric motor 50. When the motor is activated, the drive sprockets 44 and the chains 36 rotate in unison. A plurality of wheels 51 are also mounted on the shaft 46 for rotation therewith. The wheels 51 are larger than the sprockets 44 and serve to disengage the bars of the skeleton cage from between the spacing elements 38, allowing the cage to rotate.

The second free-running sprocket 42, which is located on the lower part of the setting up bed framework 34, may be mounted on a support plate 52 that is mounted for sliding movement along a beam 53 of the framework 34. By adjusting the position of this mounting plate 52, the slack in the chain 36 can be adjusted, thereby adjusting the curvature of the chain between the drive sprocket 44 and the first free-running sprocket 40 to suit the diameter of the skeleton frame 8 being constructed.

Attached to the framework 34 by means of pivot joints 54 are a plurality of curved pivoting arms 56, each of which is connected to a hydraulic cylinder 58. By actuating the cylinders 58, the arms 56 may be rotated clockwise from the position shown in Fig. 1A in solid lines to the position shown in broken lines, so as to lift a completed skeleton cage off the setting up bed 6.

The winding bed 10 is located alongside the setting up bed 6 and includes a support framework 60 that supports a plurality rotation devices 62, each comprising a pair of looped chains 64, that are spaced at regular intervals along the length of the framework.

Each pair of looped chains includes a first chain 64a that is supported on a first free-running sprocket 66a and a drive sprocket 68a, and a second chain 64b that is supported on a second free-running sprocket 66b and a second drive sprocket 68b. The first and second chains 64a, 64b cross over each other in an X-shaped configuration, subtending an angle greater than approximately 125 ° in the upper V-shaped recess formed by the chains. The first and second drive sprockets 68a, 68b are interconnected by respective first and second drive shafts 70a, 70b, which are driven via first and second belts 72a. 72b by an electric motor 74.

When the motor 74 is activated, both sets of chains 64a, 64b rotate in the same direction (clockwise in the drawing).

Attached to opposite sides of the framework 60 by means of pivot joints 76a, 76b are first and second sets of curved pivoting arms 78a. 78b. each of which arms is connected to a

hydraulic cylinder 80a, 80b. The first set of pivoting arms 78a is pivoted to the side of the framework 60 that is closer to the setting-up bed 6 and serves to lower the skeleton cage 8 gently onto the winding bed 10 to avoid damaging the chains 64 or the sprockets 66a, b and 68a, b. The second set of pivoting arms 78b is pivoted to the opposite side of the framework 60 and serves to lift the completed cage 18 off the winding bed 10 onto the off- loading ramp 16.

The wheeled trolley 12 includes a chassis 82 that is supported on a pair of wheels 84 (only one of those wheels being shown in the drawings). On one side of the chassis 82 a pair of guide arms 86 are provided, each having a pair of guide wheels 88 that engage the two upper faces of a square-section guide rail 90, which extends along the length of the winding bed framework 60. The wheels 84 are driven by an electric motor 92, causing the trolley 12 to move back and forth alongside the winding bed 10.

The trolley 12 supports a reel 14 of reinforcing wire 15 that, in use, is wound onto the skeleton cage 8. The wire is fed through a guide box 94 that is attached to the guide arm 86 by means of a pivot joint 96.

The off-loading ramp 16 consists of four sliding frames 97, two of which are provided in front of the trolley 12, the other two being provided behind the trolley. Each frame 97 consists of a steel framework 98 that supports an inclined bar 100 down which a completed cage 18 can be rolled. The frame 97 is mounted on a pair of wheels 102 that allow it to be pushed out of the way when not required, so that the trolley 12 can move freely along the side of the winding bed 10. On one side of the framework 98 a guide arm 104 is provided, having a pair of guide wheels 106 that engage the two upper faces of the guide rail 90 to guide the movement of the frame 97 along the side of the winding bed framework 60 In use, two bars 4 are transferred from the table 2 onto the chains 36 of the setting-up bed 6 and are positioned at the appropriate separation from one another, according to the planned dimensions of the cage, using the spacing elements 38. As shown in Fig. 4, the spacing between the bars will generally be proportional to the diameter of the cage although this will. of course, depend on the number of vertical bars required in that cage. Fig. 4 illustrates four example cages, each of which has six vertical bars: a small diameter cage 8a in which the separation X between the bars 4 is four times the separation of the spacing

elements 38, an intermediate diameter cage 8b in which the separation Y between the bars 4 is six times the separation of the spacing elements 38, and a large diameter cage 8c in which the separation Z between the bars 4 is nine times the separation of the spacing elements 38.

After two bars 4 have been transferred 2 onto the chains 36 of the setting-up bed 6, pre- formed mild steel bands 110 are placed on the bars 4 at the required separation from one another and each of those rings is then secured to the bars, for example by welding, tying, bolting or clamping. A third bar 4 is then transferred onto the chains and located by the spacing elements 38 at the appropriate spacing from the first two bars, and the chains 36 are rotated so that the bands 110 of the partially-completed skeleton cage fall onto the third bar, whereupon they are secured to that bar. This process is repeated until all of the bars have been located and secured to the bands 110, thereby completing the skeleton cage 8, as illustrated schematically in Fig. 5.

The completed skeleton cage 8 is transferred onto the winding cage by raising the pivoting arms 56 to lift the skeleton cage from the setting-up bed 6 and simultaneously raising then lowering the second set of pivoting arms 78a to lower the skeleton cage gently onto the chains 64a, b of the winding bed 10. The free end of the reinforcing wire 15 is secured to the skeleton cage adjacent a first end of that cage, for example by welding, tying, bolting or clamping, and the motors 74 and 92 are then activated, causing the cage to rotate and simultaneously driving the trolley 12 from one end of the winding bed to the other. This results in a length of reinforcing wire being wrapped helically around the skeleton cage in a continuous coil from one end of the cage to the other, as shown schematically in Fig. 6.

When the winding process has finished, the motors 74,92 are halted and the reinforcing wire is secured to the second end of the skeleton cage 8, after which the unwound length of reinforcing wire can be cut off. Although securing the reinforcing wire to the skeleton cage at both ends is sufficient to hold it in place initially, the structure may be made stronger by securing the reinforcing wire at various intermediate positions, thereby completing the cage. The completed cage 18 is lifted from the winding bed by raising the third set of arms 78b. so that the cage rolls away down the off-loading ramp 16.

After the cage has been completed, it is not necessary to drive the trolley 12 back to the first end of the winding bed before winding the reinforcing wire onto the next cage: instead, by reversing the direction of the winding bed motor 74 and feeding wire to the bottom of the cage (as shown in thin lines in Fig. 1B) while driving the trolley 12 in the opposite direction, an identical cage can be made.

An optional feeder system for the cage making machine is shown in figures 8 to 11. This replaces the wire delivery device 12 and is arranged to feed reinforcing wire 15 to the winding bed 10 from a static coil of steel wire 122.

The feeder system includes a feeder arm assembly 120 that is mounted for bi-directional movement parallel to the winding bed 10. Reinforcing wire 15 from the coil 122 is fed through the feeder arm assembly as it is wound onto the skeleton cage 8, the feeder arm assembly serving to guide placement of the wire on the skeleton cage 8.

The feeder arm assembly, which is shown in more detail in figures 9 to 11, is constructed as an open steel framework 122 that is mounted on a pair of wheels 124, which are driven by electric motors 126. A pair of guide arms 128, which are similar to the guide arms 86, engage the guide rail 90 to guide the feeder arm assembly as it travels backwards and forwards along the length of the winding bed 10.

The upper part of the framework includes an inlet gate 130 for guiding the reinforcing wire into the feeder arm assembly and an outlet gate 132 for guiding the wire as it leaves. Three rollers 134 with vertical axes are provided to guide the wire 15 as it bends through an angle of 90° from the inlet gate to the outlet gate. The inlet gate 130 includes two horizontal guide rollers 136 and two vertical rollers 138 arranged in a square, and the wire 15 passes through the centre of this square. The outlet gate 132 includes three wheels that are arranged to form a triangle. The wire 15 passes through the nip between these rollers and is therefore guided very precisely as it leaves the outlet gate and is wound onto the skeleton cage 8.

In use, the feeder arm assembly travels along the length of the winding bed 10, guiding the reinforcing wire as it is wound onto the skeleton cage 8. The coil 122 is static and located

towards one end of the winding bed 10. As the coil 122 is not carried by the feeder arm assembly, the weight of the assembly is considerably reduced.

A further option (not shown) comprises the provision of a robot arm having a welding attachment for welding the reinforcing wire to the skeleton cage. The robot arm may be computer-controlled and/or may make use of programmable logic controllers (PLCs).

Operation of the cage making machine may be fully or partially computer-controlled. For example, the speed of the motors driving the winding bed and the feeder arm assembly may be controlled according to predetermined programs to produce cages on which the reinforcing wire is wound with a predetermined helical pitch. The pitch may be uniform as shown in figure 12, or it may vary along the length of the cage, as shown in figure 13.

For example, the cage shown in figure 12 may be 12000mm long with an effective length (on which the reinforcing wire is wound) of 11000mm and an unreinforced projection at one end of 1000mm, and a diameter of 900mm. The helical reinforcing wire has a uniform 100mm pitch. The cage shown in figure 13 may also be 12000mm long with an effective length of 11000mm and a diameter of 900mm. The cage has a first section 140a with a 100mm pitch, a second portion 140b with a 150mm pitch and a third portion 140c with a 200mm pitch.

The change in pitch may be produced by altering the traversing speed of the feeder arm assembly, a higher traversing speed producing a larger pitch. Alternatively, or in addition, the rotation speed of the winding bed may be adjusted, a faster rotation speed producing a smaller pitch.

The correct rotation and traversing speeds for cages of predetermined diameters and pitches may be stored in the computer in a look-up table or, alternatively, they may be calculated by the computer using predetermined algorithms.

The computer may also be used to control operation of a robot arm having a welding attachment for welding the reinforcing wire to the skeleton cage.