The present invention relates to an apparatus for tying coils of wire.

In the Australian wire mills of Waratah wire Products in Geelong and Sydney the final steps in the production process for producing wire involve winding the wire produced by the wire drawing lines into coils of required length and securely tying the coils for distribution to customers.

One known method of coiling/tying wire produced by wire mills comprises feeding wire emerging from a galvanising station to a winding head assembly and dispensing a measured length of the wire onto a frame so that the wire wraps around the frame and forms a coil of the required length. An operator thereafter:

(a) cuts the wire to separate the wire on the frame from the upstream wire from the galvanising station;

(b) manually ties a number of short lengths of wire around segments of the coil; and

(c) removes the tied coil from the frame.

Typically, at least four ties equi-spaced around the circumference of the coil are used to tie each coil.

During the time required for the operator to cut, manually tie and remove the tied coil from the frame, the wire which continues to emerge from the galvanising station is accumulated upstream of the winding head assembly and, after the tied coil is removed, dispensed onto the frame and the above described tying procedure is repeated.

There are a number of problems associated with the foregoing method of coiling/tying wire. For example, to a large extent the coiling/tying step controls the rate of production of the mills because the production rate has to be matched to the time required for an operator to carry out the cutting/tying/coil removal steps. As a consequence, the maximum production rate is well below the capacity of the wire-drawing and other equipment for producing galvanized (or plain wire) . Secondly, there are a number of quality control problems associated with manual tying. One problem is that there are difficulties forming a tight tie on a coil and reproducing four or more such ties of constant tension on a coil. Another problem is that the coils tend to have a non-uniform transverse section which makes stacking of coils difficult and generally detracts from product presentation. In some instances, the diameter of the coil segment in the region of the final tie on a coil may be up to 50% larger than the

diameter of the coil in the region of the previous ties.

In order to alleviate the above problems various coil tying machines have been developed. These machines comprise an assembly of two semi-circular inwardly facing channel members which are pivoted together and can be closed around a segment of a coil. The channel members are formed to define a circular guide along which, in use of the assembly, a length of wire is pushed to form a series of loops around the segment of the coil. The length of wire thereafter is tensioned, cut, and tied to complete the process. The machines have not been altogether successful in a number of applications, such as the production of fencing wire, and in these applications are not considered to be a significantly better option than the manual tying practice. By way of example, two specific limitations of the machines are that the tied lengths of wire tend to have sharp ends which stick out from the coils and present "cut- hazards" for persons handling the coils and only a relatively small number of loops of wire can be produced by the pushing action of the machines.

An object of the present invention is to provide a coil tying apparatus which alleviates the problems of manual tying and the known coil tying machines as noted above.

According to the present invention there is provided an apparatus for tying a coil of wire with a tie, the apparatus comprising:

(a) a winder head assembly for holding an end of the tie; and

(b) a drive means for moving the winder head assembly in a path around a segment of the coil to wrap the tie a predetermined number

of times around the coil segment.

It is preferred that the apparatus further comprises a means to secure together the ends of the wrapped tie.

It is preferred that the path be a circular path.

It is preferred that the apparatus further comprises a means for tensioning the wrapped tie to a predetermined tension.

It is preferred particularly that the tensioning means comprises, a pair of pinch rollers which are arranged so that the tie passes between the rollers before being wrapped around the coil segment, and a means for driving at least one of the pinch rollers and thereby the tie in a direction opposite to the wrapping direction of the tie holding means to tension the tie to the predetermined tension.

It is preferred that the tie be a length of wire.

It is preferred that the securing means be an assembly for resistance welding together sections at opposite ends of the tie wire.

It is preferred particularly that the resistance welding assembly be adapted to form rounded terminal ends of the tie wire after the end sections of the tie wire are resistance welded together by melting sections of the tie wire.

It is particularly preferred that the resistance welding means comprises, an assembly of three pairs of contact electrodes with a central electrode pair and an

outer electrode pair on each side of the central electrode pair, the central electrode pair being adapted to hold together and resistance weld the end sections of the wrapped tie wire, and the outer electrode pairs being adapted to form the terminal ends of the tie wire by:

(a) one pair of the outer electrodes holding the tie wire at a location between the welded end sections of the tie wire and the holding means and, with the central electrode pair, melting the tie wire at the location, and

(b) the other pair of outer electrodes holding the tie wire at a location between the welded end sections of the tie wire and a tie wire dispenser and, with the central electrode pair, melting the tie wire at the location.

According to the present invention there is also provided an apparatus for tying a coil of wire with a tie wire comprising:

(a) a means for wrapping the tie wire a predetermined number of loops around a segment of the coil; and

(b) a means for resistance welding together sections of opposite ends of the tie wire and for simultaneously or thereafter forming rounded terminal ends of the tie wire.

It is preferred that the resistance welding means comprises, an assembly of three pairs of contact electrodes with a central electrode pair and an outer electrode pair

on each side of the central electrode pair, the central electrode pair being adapted to hold together and resistance weld the end sections of the looped tie wire, and the outer electrode pairs being adapted to form the terminal ends of the tie wire by:

(a) one pair of the outer electrodes holding the tie wire at a location between the welded end sections of the tie wire and the holding means and, with the central electrode pair, melting the tie wire at the location, and

(b) the other pair of outer electrodes holding the tie wire at a location between the welded end sections of the tie wire and a tie wire dispenser and, with the central electrode pair, melting the tie wire at the location.

According to the present invention there is also provided a method of tying a coil of wire with a tie comprising:

(a) dispensing the tie so that an end is received and held by a winder head assembly; and

(b) moving the winder head assembly in a path around a segment of the coil to loop the tie a predetermined number of times around the segment; and

(c) tying-off the tie wire.

It is preferred that the path be circular.

It is preferred that the method further comprises tensioning the looped tie to a predetermined tension prior to tying off the tie.

It is particularly preferred that the tensioning step comprises, after completing step (b) of wrapping the tie around the coil segment, driving the tie in a direction opposite to the direction of looping the tie around the coil.

It is preferred that the tie be a length of wire.

It is preferred that the method further comprises tying off the wire by resistance welding together sections at opposite ends of the tie wire.

It is particularly preferred that the method further comprises forming rounded terminal ends of the tied-off tie wire.

According to the present invention there is also provided a coil of wire tied by means of the apparatus described above.

According to the present invention there is also provided a coil of wire tied in accordance with the method described above.

The present invention is described further by way of example with reference to the accompanying drawings in which:

Figure 1 is a perspective view of the overall assembly of a preferred embodiment of a coil tying apparatus in accordance with the present invention;

Figure 2 is a front elevation of a winder head

assembly which forms part of the coil tying apparatus shown in Figure 1;

Figure 3 is a rear elevation of the winder head assembly shown in Figure 2;

Figure 4 is a perspective view of a weld and finish assembly which forms a further part of the tying apparatus shown in Figure 1;

Figure 5 is a perspective view of a tie wire dispensing and tensioning assembly which forms a further part of the coil tying apparatus shown in Figure 1; and

Figures 6 to 13 are simplified sketches illustrating the method steps for tying a coil of wire in accordance with a preferred embodiment of the method of the present invention.

The overall assembly of the coil tying apparatus shown in Figure 1 comprises, a cradle 3 for supporting a coil 5 of wire in a generally horizontal position, a winder head assembly, generally identified by the numeral 7, for wrapping a tie wire (not shown in Figure 1 but shown in Figures 6 to 13) a predetermined number of loops around a segment of the coil 5, a dispensing and tensioning assembly, generally identified by the numeral 9, for dispensing and thereafter tensioning the looped tie wire, and a resistance welding and finishing assembly, generally identified by the numeral 11, for tying-off the tie wire.

The coil tying apparatus may be used at any suitable location in a wire drawing production process. However, advantageously, the coil tying apparatus is not a direct stage in a wire drawing line for producing uncoated wire and/or a galvanising line for producing galvanised wire.

With further reference to Figure 1, the cradle 3 comprises a vertically disposed central shaft 13, which is mounted for rotation about the vertical axis of the shaft 13, and a series of support arms 15 extending radially from the shaft 13 and defining rests for the coil 5. The cradle 3 further comprises pairs of spaced apart legs 17 extending upwardly from the support arms 15 to minimise movement of the coil 5 once the coil 5 positioned on the cradle 3.

With reference to Figures 2 and 3, the winder head assembly 7 for wrapping a tie wire a predetermined number of loops around the segment of the coil 5 comprises, a generally horse-shoe shaped ring gear assembly 19 and a tie wire clamping assembly 20 mounted to one end of the ring gear assembly 1 . The ring gear assembly 19 is coupled to a generally ϋ-shaped support frame 23 by means of a pinion assembly 21 (Figure 3) and the support frame 23 in turn is coupled to a vertical slide rail 25 extending from a base 31. The ring gear assembly 19 can be moved between a raised position, as shown in Figures 2 and 3, and a lowered position, as shown in Figure 1, by means of a pneumatic piston/cylinder assembly 27. The pinion assembly 21 is connected by means of pulleys 29 (Figure 2) and a timing belt 31 (Figure 2) to an electric servo motor 33. The motor 33 is operable through the belt/pulley coupling 29, 31 and the pinion assembly 21 to rotate the ring gear assembly 19. It can readily be appreciated that such movement of the ring gear assembly 19 would have the effect of moving the wire clamping assembly 20, and any tie wire held by the wire clamping assembly 20, in a circular path around an axis A (Figures 2 and 3);

The lowered position of the support frame 23 is the operative position of the ring gear assembly 19. It can readily be appreciated that when the support frame 23 is in a raised position, as shown in Figures 2 and 3, the coil 5 of wire can conveniently be located between the

support frame 23 and the base 31 of the slide rail 25 and, when moved to the lowered position, as shown in Figure 1, the ring gear assembly 19 encloses a segment of the coil 5.

With particular reference to Figure 5, the dispensing and tensioning assembly 9 comprises a pair of pinch rollers 37 for:

(a) initially receiving and dispensing a tie wire towards and into engagement with the wire clamping assembly 20 on the ring gear assembly 19; and

(b) after the tie wire has been wrapped a predetermined number of loops around the segment of the coil 5 at that time enclosed by the ring gear assembly 19, for tensioning the tie wire to a predetermined tension.

The upper one of the pinch rollers 37 is formed with a groove 41 for guiding the tie wire. In addition, the upper pinch roller is connected by means of a drive shaft 43 and a pulley/drive belt assembly 45 to an electric servo motor 47. The motor 47 is operable selectively to drive the upper one of the pinch rollers 37 in forward or reverse directions as required to dispense or tension the tie wire.

With particular reference to Figure 4, the dispensing and tensioning assembly 11 for tying-off the tensioned tie wire wound around the segment of the coil 5 at that time enclosed by the ring gear assembly 19 comprises 3 pairs of electrodes 49a, 49b, 51a, 51b, and 53a, 53b arranged side by side and operatively supported to resistance weld together sections at opposite ends of the tie wire and thereafter to form rounded terminal ends of

- li ¬ the welded tie .

Specifically, the central pair of electrodes 49a, 49b is mounted to a support frame, generally identified by the numeral 57, for pivotal movement about a pivot point 59 to clamp the tip portions of the electrodes around end sections of the tie wire which are held by the apparatus in overlapping relationship, as shown in Figure 13, so that thereafter an electrical current passed through the electrodes 49a, 49b welds together the end sections of the tie wire.

Each of outer pairs of electrodes 51a, 51b and 53a, 53b is similarly mounted to the support frame 57 for pivotal movement about the pivot point 59 to clamp the tip portions of the electrodes around a section of the tie wire intermediate the welded section of the tie wire and a respective end of the tie wire so that an electric current passed through the electrodes 49a and 53a or through the electrodes 49a and 51a melts the clamped section of the tie wire and forms a rounded terminal end.

The electrode pairs 49a, 49b, 51a, 51b, and 53a,

53b are pivotally movable between the open positions shown in Figures 5 and 6 and the closed operative positions discussed above by the cooperative action of pneumatic piston/cylinder assemblies 61, 63.

In addition, the whole tensioning and finishing assembly 11 is supported by a linear bearing rail 67 and is movable selectively therealong to bring the assembly into and form an operative position in relation to a tie wire.

The coil tying apparatus further comprises:

(a) an hydraulic press (not shown) for pre- compressing a coil 5 of wire before the

coil is placed on the cradle 3; and

(b) a control system (not shown) to determine the size of a coil 5 of wire to be wrapped and thereafter to select a required length of tie wire to wrap around the coil 5.

With reference to Figures 6 to 13 the preferred embodiment of the method of tying a tie wire, numbered 71 in Figures 6 to 13, to a segment of a coil of wire comprises the following steps.

1. (Figure 6) - with the ring gear assembly 19 in a raised position, locating the coil 5 on the cradle 3 (not shown) .

2. (Figure 7) - moving the ring gear assembly 19 into a lowered position in the direction of the arrow X.

3. (Figures 8 & 9) - when the ring gear assembly 19 is in the lowered position, rotating the ring gear assembly 19 in the direction of the arrow A to position the wire clamping assembly 20 in a "pick-up" position in line with the tie wire 71 (as shown in Figure 9) .

4. (Figures 8 & 9) - when the wire clamping assembly 20 is in the pick-up position, actuating the pinch rollers 37 to rotate in the direction of the arrows Z to dispense the tie wire 71 so that a free end of the tie wire 71 is received in and held by the wire clamping assembly 20.

5. (Figure 9) - when the free end of the tie

wire is received and held by the wire clamping assembly 20, simultaneously rotating the ring gear assembly 19 in the reverse direction, as indicated by the 5 arrow B and continuing to rotate the pinch rollers 37 in the direction of the arrows Z (Figure 9) so as to wrap the tie wire 71 a required number of times around the segment of the coil 5 at that time enclosed by the 10 ring gear assembly 19 to provide the required number of loops of the tie wire 71.

6. (Figure 10) - at a predetermined point in the wrapping sequence, stopping the

15 rotation of the pinch rollers 37 so that the pinch rollers 37 clamp that end of the tie wire 71 and allowing the ring gear assembly 19 to continue to rotate as required to complete the wrapping sequence

20 and thereby to partially tension that end section of the tie wire 71 held by the wire clamping assembly 20.

7. (Figures 11 - 12) - at the conclusion of the wrapping sequence, with the ring gear

25 assembly 19 in a stationary position, operating the pinch rollers 37 in a reverse direction, as shown by the arrow D, to pull that end section of the wrapped tie wire 71 tightly against the coil 5 and thereafter

30 to place the tie wire 71 under a predetermined tension.

8. (Figure 13) - resistance welding overlapping sections of the free ends of the tie wire 71 and forming rounded

terminal ends of the resistance welded tie and thereafter cutting the tie wire 71.

9. Rotating the cradle 3 about the shaft 13 to bring another segment of the coil 5 into a position within the ring gear assembly 19, and repeating steps 1 to 8.

The above described apparatus and method has a number of advantages over the prior art arrangement.

An important advantage is that the orbital action of the ring gear assembly 19/wire clamping assembly 20 pulls the tie wire around the coil 5 rather than pushes the tie wire, as is the action of the known coil tying apparatus. As a consequence, there is significantly less resistance to wrapping of the tie wire and a larger number of loops of tie wire can be wrapped around the coil.

Many modifications may be made to the preferred embodiment described above without departing from the spirit and scope of the present invention.