WO2000066292A1

WO2000066292A1 - Helical winding machine

Info

Publication number: WO2000066292A1
Application number: PCT/GB2000/001488
Authority: WO
Inventors: Robert Slater
Original assignee: Rom Group Limited
Priority date: 1999-04-29
Filing date: 2000-04-28
Publication date: 2000-11-09
Also published as: GB9909755D0; AU4419100A

Abstract

This invention relates to a helical winding machine (10), and in particular to a machine for winding a length of wire into a helix, and for cutting the wire to length. Such a machine will have its prime utility for the preparation of helixes for use in cages for reinforced concrete piles and the like. According to the invention, the cutting means (22) for cutting the wire (44) is located dowsntream of the coiling means (18), enabling a reduction in the number of process steps to form a finished helix (44b), and enabling a reduction in the time for which the machine must stand idle between forming operations.

Description

HELICAL WINDING MACHINE

FIELD OF THE INVENTION

This invention relates to a helical winding machine, and in particular to a machine for winding a length of wire into a helix, and for cutting the wire to length.

Such a machine will have its prime utility for the preparation of helixes for use in cages for reinforced concrete piles and the like, and the following description will relate primarily to such use. However, the use of the machine for other applications is not thereby excluded.

BACKGROUND TO THE INVENTION

Reinforced concrete piles are known for use in the foundations of roadway bridges and the like. The piles are sunk deep into the ground and can for example provide a link between the bridge supports and the underlying rocks. The cage comprises a number of bars which in use are arranged to lie substantially along the longitudinal axis of the pile. The bars are interconnected so as to maintain their separation and alignment. The bars are often interconnected by a helical wire. The helical wire also acts to increase the lateral loading which the pile can withstand, and in piles designed to withstand lateral loading a helical wire is usually mandatory.

The cage acts both as a reinforcement for the concrete and also as a means to tie the bridge support or the like to the pile.

The cage is typically assembled on site, the helical wire being joined to the cage bars by wire ties located at all or some of the junctions therebetween. The helical wire may itself also be manufactured on site, though typically this will be manufactured elsewhere on a dedicated machine, and shipped to the site in "compressed" form, i.e. with adjacent loops of the helix in engagement with each other, the helical wire being stretched out during assembly of the cage so that the adjacent loops are separated by the required distance corresponding to the required pitch of the helix.

DESCRIPTION OF THE PRIOR ART

Helical winding machines are known. One such machine is called the KRB #6/20 SpiralMatic spiral bender supplied by P.F. LaRoche & Co. Ltd., of Units 11 and 12 Danes Road Industrial Estate, Romford, RM7 OHL, England. With this machine wire is taken from a supply roll, passed through a set of straightening rollers, passed through a set of drive rollers, passed alongside a cutter, and then passed to a set of bending or coiling rollers. The bending rollers are spaced apart and are positioned to determine the diameter and pitch of helix to be formed. The formed helix is supported by a pole carried by the machine, the pole being rotatably mounted and driven by the wire so as not to cause undue drag upon the wire, which drag might cause the diameter of the helix to increase unwantedly.

When a helix of the required number of loops has been formed, the drive rollers are switched off and the cutter is activated to cut the wire. The formed helix is then removed from the pole, and the trailing end is removed by a subsequent cropping action.

STATEMENT OF THE INVENTION

It is the object of the present invention to provide an improved helical winding machine which reduces or avoids the disadvantages of the prior art machines, which disadvantages are set out below.

According to the invention there is provided a helical winding machine comprising feeding means for the wire, coiling means for the wire, supporting means for the formed coil of wire, and cutting means for cutting the wire, characterised in that the cutting means is located downstream of the coiling means.

Because the cutting means is located downstream of the coiling means, the wire is only cut by the machine after it has begun to be formed into a coil. Accordingly, when the wire is cut it is already bent into the shape of a coil and there is no requirement to arrange for a subsequent cropping step to remove the trailing end of the wire. Thus, with the prior art machines, of which the machine described above is typical, the cutting means is upstream of the coiling means, so that when the wire is cut a substantially straight section of wire remains at the trailing end. It is this straight section of wire which needs to be removed by the subsequent cropping step, which subsequent step is avoided by the present invention. Alternatively stated, with the present invention the trailing end of the wire is of helical form and not of linear form.

Preferably, the cutting means is adjacent the supporting means, and is desirably downstream of the supporting means. In such embodiments, the supporting means will provide support for the helix adjacent the point to be cut. In the desirable embodiments, the supporting means will provide support for the leading end of the subsequent helix after the wire has been cut.

Usefully, the cutting means is at least two loops of the helix downstream of the coiling means. In such embodiments, when a formed helix is cut, at least two turns of the subsequent helix have already been formed. Thus, with the present invention the wire for the subsequent helix has already commenced its coiling and will continue coiling with minimum disruption and delay. On the other hand, when using the prior art machines, it is either necessary for the leading end of each helix to be manually fed into the bending rollers by a dedicated operator, or else complex automatic guiding means are required to ensure correct take- up of the leading end of the subsequent helix. In addition, the time for which the feeding means such as the drive rollers must be switched off is minimised, i.e. with the present invention the feeding means needs to be switched off only for the (very brief) time taken for the cutting means to cut the wire; with the prior art machines the drive rollers have to be switched off whilst the wire is cut and remain off until the leading end of the subsequent helix has been correctly fed to the bending rollers.

Usefully, the machine includes a mast member; usefully also the mast member carries the supporting means. In such embodiments, the supporting means can be movable relative to the mast member, to support formed helixes of differing diameters. Desirably, the mast member also carries the cutting means; desirably also the cutting means is movable relative to the mast member. Preferably, the supporting means and the cutting means are connected to move together relative to the mast member.

Preferably, the coiling means acts to coil the wire upwardly (i.e. against the force of gravity). In this way, the diameter of the coil is controlled only by the height of the mast, which can in theory be as high as the roof of the building in which the machine is operating. The prior art machines, on the other hand, act to coil the wire downwardly, so that the maximum diameter of the helix is set by the height of the bending rollers above the floor or ground. In practice, the maximum helix diameter for such a machine is typically around 1.5 metres. BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described, by way of example, with reference to the accompanying drawings, in which:-

Fig.l is a front view of the helical winding machine according to the invention;

Fig.2 is a plan view of the machine of Fig.l; and

Fig.3 is a schematic view of the cutter means with several loops of a helix shown in section.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The helical winding machine 10 comprises a set of straightening rollers 12,14 a set of drive rollers 16, bending or coiling rollers 18, supporting bar 20, and cutter assembly 22.

The straightening rollers 12 and 14 are orthogonally arranged, so that the rollers 12 straighten the fed wire (not shown) in one dimension, whilst the rollers 14 straighten the wire in the perpendicular dimension. The straightening rollers are of known construction, and are adapted to straighten the wire as it is fed from a supply roll (not shown).

The drive rollers 16 are also of known construction, and are connected to a motor 24 (Fig.2), which can drive the rollers at a predetermined rotational rate which corresponds to a predetermined linear rate for the fed wire.

Between the drive rollers 16 and the bending rollers 18 are arranged guides 26. The fed wire passes through the guides, which serve to prevent the wire from buckling as it is pushed into the bending rollers 18. The number and spacing of the guides can be chosen for the diameter of wire being fed, i.e. a thinner wire will typically require more, closer spaced, guides 26.

The set of bending rollers 18 comprise three separate rollers 30,32 and 34. These rollers are driven to rotate by the fed wire, i.e. it is only the drive rollers 16 which are "active" and drive the fed wire, all the other rollers are passive.

The rollers 30,32,34 are in the form of pulleys, i.e. each has a central groove 36 within which a part of the (cicular) wire can lie. It will be understood that the rollers 30 and 34 are offset relative to the path of the fed wire, and in combination with the roller 32 cause the wire to become bent upwardly, i.e. towards the top of the drawing in Fig.l. In addition, the roller 34 can be offset along the direction of its axis of rotation, i.e. the direction out of the paper in the orientation of Fig.l and downwardly as viewed in the orientation of Fig.2. In this way, the wire can be formed into a helix, so that as the fed wire continues to be bent, the formed loops progress outwardly of the paper in Fig.l, and downwardly in Fig.2. Accordingly, the rollers 30,32,34 together act to bend the wire into a helical form.

The roller 32 is fixed to the base 38 of the machine, whilst the rollers 30 and 34 are movable relative thereto. Thus, both rollers 30 and 34 are movable upwardly and downwardly as viewed in Fig.l, so as to vary the degree of bend imparted to the wire and so determine the diameter of the helix.

In addition, the relative movement of the roller 34 along its axis of rotation will determine the pitch of the helix, and in particular whether the resulting adjacent loops of the helix engage one another, or are spaced apart. Thus, with smaller section wire, in which it is possible for the helix to be stretched out on site, it is typical to form the helix with a pitch substantially equal to the diameter of the wire, so that adjacent loops engage one another. In this way, the helix occupies a minimum volume whilst being transported. With larger section wire, on the other hand, it may not be possible or practical to stretch out the helix on site, so that the helix has to be formed on the machine with its predetermined pitch.

The bent wire is subsequently passed between two guide rollers 40, and thereafter over supporting pole 20. The supporting pole 20 is designed to carry substantially all of the weight of the formed helix, and therefore extends by a distance L (Fig.2) from the base 38. The supporting pole 20 is rotatably mounted, so that it can be driven to rotate by the fed wire, and does not cause undue drag upon the wire, which drag could cause the diameter of the helix to increase as the number of loops in the helix increases.

Adjacent the supporting pole 20 is the cutter assembly 22. As better seen in Fig.3, the cutter assembly comprises an aperture 42 through which the fed wire 44 can pass. Guided to move within the aperture is a blade 46 which can be driven by the motor 48. When it is desired to cut the wire, the drive rollers 16 are stopped, and the motor 48 is activated to cause the blade 46 to cut the wire. When the wire is cut the leading end of the next helix is already formed into a helical shape, and already lies within the aperture 42, so that when the drive rollers 16 are restarted the leading end continues its passage through the aperture 42 to form the next helix, with minimum operator involvement and minimum stoppage of the drive rollers.

In this embodiment, the cutter assembly is arranged to act upon the third loop of the helix, i.e. there are already two complete loops 44a of the helix before the wire passes through the aperture 42. Clearly, therefore, the cutter assembly 20 is arranged to be movable into and out of the paper as drawn in Fig.l, so as to ensure that the cutter assembly can act on the third loop regardless of the pitch of the helix.

During formation of the helix, the loops 44b downstream of the cutter assembly 20 are of the predetermined pitch, in this embodiment equal to the diameter of the wire 44, so that adjacent loops interengage.

In alternative embodiments it would be possible to arrange the cutter assembly 20 to act on other loops of the helix, such as the first, second or even fourth; however, it is believed that the third loop is the most suitable.

In this embodiment the cutter assembly 22 and the supporting pole 20 are connected together and mounted upon mast 50.

The mast 50 comprises two guide bars 52 and a drive screw

54. The drive screw 54 is rotatably driven by motor 58, and rotation of the drive screw 54 acts to raise or lower the cutter assembly 22 and the supporting pole 20. Thus, the chosen diameter of the helix (as set by the bending rollers

30,32 and 34, will determine the required position of the supporting pole 20 and the cutter assembly 22. It will be understood that the guide rollers 40 are also movable relative to the base 38, to accommodate helixes of differing diameters.

In other embodiments the cutter assembly 22 can be mounted separately to the supporting pole 20, but it will preferably always be mounted so that it is movable towards and away from the axis of the formed helix (so that the cutter can always lie at the circumference of the helix for any helix diameter); preferably also the cutter assembly will be mounted to be movable parallel to the axis of the formed helix also, as indicated above.

As described above, since with this machine the helix is coiled upwardly (i.e. the roller 34 is arranged above the roller 30 in the gravitational direction), the maximum diameter of helix which can be formed is determined by the height of the mast 58, and in particular the maximum height available to the supporting pole 20. Clearly, the machine can be manufactured with a mast of the appropriate height for the chosen or expected helixes.

The machine includes a control box 60 by which the positions of the bending rollers 30,34, the guide rollers 40, the supporting bar 20 and the cutter assembly 22 can be set. The control box can also be used to set the length of wire to be formed into a helix, i.e. the number of loops in the helix between operations of the cutter, which length will be determined by the number of rotations (and perhaps part rotations) of the drive rollers 16.

The control means can also set the rate of rotation of the drive rollers 16, which may be varied depending upon the thickness of the wire and/or the diameter of the helix. Thus, it might be expected that a thinner wire could be bent more rapidly, and also that a smaller diameter helix (in which a greater degree of bend is imparted into the wire) should be bent more slowly than a larger diameter helix of the same wire. The control box 60 can include a memory to store all of the above information, so that the requirements for a particular customer or application can readily be called up and the machine settings adjusted as necessary.

Claims

1. A helical winding machine for winding a length of wire into a helix, comprising feeding means for the wire, coiling means for the wire, and cutting means for cutting the wire, characterised in that the cutting means is located downstream of the coiling means.

2. A helical winding machine according to claim 1 in which the cutting means is movable towards and away from the longitudinal axis of a formed helix.

3. A helical winding machine according to claim 1 in which the machine has supporting means to support a formed coil of wire.

4. A helical winding machine according to claim 3 in which the machine has a mast member arranged to be substantially vertical in use, the supporting means being movably mounted upon the mast member.

5. A helical winding machine according to claim 4 in which the cutting means is also movably mounted upon the mast member, and in which the cutting means is downstream of the supporting means.

6. A helical winding machine according to claim 4 in which the machine has a mast member arranged to be substantially vertical in use, the supporting means being carried by the mast member.

7. A helical winding machine according to claim 1 in which the coiling means acts to coil the wire upwardly in use, i.e. against the force of gravity.

8. A helical winding machine according to claim 1 in which at least one guide member is located between the coiling means and the cutter means.

9. A helical winding machine according to claim 1 in which the coiling means comprises a set of three rollers, at least one of the rollers being movable perpendicular to its axis of rotation so as to vary the diameter of a formed helix.

10. A helical winding machine according to claim 9 in which at least one of the rollers is movable parallel to its axis of rotation so as to vary the pitch of a formed helix.

11. A helical winding machine according to claim 9 in which the cutting means is movable substantially parallel to the axis of rotation of the rollers.

12. A method of forming a helical wire comprising the steps of: {i} drawing a wire from a feeder roll, {ii} passing the wire through straightening means, {iii} passing the straightened wire through a drive means, {iv} passing the driven wire through a coiling means so as to form the wire into a helical shape, {v} subsequently passing the coiled wire adjacent a cutting means so that the wire has been formed into a helix or part-helix before passing the cutting means, {vi} interrupting the drive means after a predetermined length of wire has passed the cutting means, and {vii} operating the cutting means to cut the wire.