FIELD OF THE INVENTON THIS INVENTION relates to handling of shock tube. More particularly, the invention relates to handling a bulk length of shock tube to provide shock tube coils comprising discrete lengths of the bulk length of shock tube. The invention provides a shock tube coiling device and a method of producing shock tube coils. BACKGROUND TO THE INVENTION

SHOCK TUBE is widely used as a detonation signal transmitter in explosives detonation applications. It comprises a length of hollow plastic tube with a semi-rigid resilient character, filled with a high explosive such as HMX. Usually, shock tube is manufactured in bulk lengths not readily suitable for use in explosives detonation applications. For such usage, shock tube is generally cut into shorter lengths that are coiled, thereby to facilitate storage and handling of the shock tube during transport and prior to use. Each end of a shock tube coil so obtained typically carries a detonator.

In the Applicant's experience, coiling shock tube is a laborious and cumbersome exercise since shock tube is, due to its semi-rigid, resilient character, difficult to handle particularly when being coiled. It will be understood that it is undesirable for shock tube to be strained too heavily when being or in having been coiled, since overstraining thereof could impact negatively on tube wall strength and thus also on detonation signal transmission efficiency in use.

In order to facilitate shock tube coiling, coiling operations are generally mechanised. The Applicant has, however, encountered operating difficulties with existing coiling devices in that these are labour-intensive, requiring a significant extent of operator intervention, and slow in their operation. The present invention seeks to address these operating difficulties in particular.

SUMMARY OF THE INVENTION

IN ACCORDANCE WITH ONE ASPECT OF THE INVENTION, there is provided a shock tube coiling device for producing shock tube coils comprising discrete lengths of shock tube from a bulk length of shock tube, the device including

at least one group of at least three shock tube coiling hubs, the coiling hubs of the group being mounted about an indexing axis, each coiling hub being radially spaced from the indexing axis and being angularly spaced from the other coiling hubs about the indexing axis, the coiling hubs of the group being displaceable in an operating direction to follow each other along an endless indexing path about the indexing axis and each coiling hub comprising at least one coil support member about and onto which shock tube can, in use, be coiled about a coiling hub axis which is defined by the coiling hub; and

a shock tube coiling member that is rotatably mounted for rotation along a coiling path about a coiling axis and which is capable of coiling, at a shock tube coiling position along the indexing path and through such rotation along the coiling path about the coiling axis, shock tube about and onto the at least one coil support member of any one of the coiling hubs of the group of coiling hubs when that coiling hub is located at the shock tube coiling position in use.

Typically, the device will have only one group of coiling hubs and the invention is therefore described accordingly hereinafter. Nevertheless, it will be appreciated that the device may have more than one group of coiling hubs. In such a case, such additional groups will, however, operate independently of other groups.

The group of coiling hubs may be mounted on a coiling hub support member. The coiling hub support member may define the indexing axis and may be rotatably mounted for rotation about the indexing axis. Rotation of the coiling hub support member, in use, may sequentially and individually bring each coiling hub of the group of coiling hubs into the coiling position.

The device may include respective servo motors which respectively drive, in use, rotation of the coiling hub support about the indexing axis and rotation of the coiling member about the coiling axis.

Preferably, the group of coiling hubs comprises only three coiling hubs. The coiling hubs of the group of coiling hubs may, with reference to their respective coiling hub axes, be spaced equidistally from and equiangularly about the indexing axis. It will be appreciated that the coil axes of the coiling hubs may therefore all lie on the circumference of a hypothetical circle having the indexing axis as its centre. The indexing path may then, naturally, run along such a circumference. In the preferred embodiment in which three coiling hubs are provided, the angular spacing of the coiling hubs from each other about the indexing axis may be about 120°. For other configurations in which more than three coiling hubs are provided in the group of coiling hubs, the angular spacing may be between about 60 ^° and about 120 ^° , typically 60 ^° , 72 ^° or 90 ^° .

Each coiling hub may define an outer circumference of about 500mm. Each coiling hub may therefore have a diameter of about 160mm. When only one coil support is provided for any one or more of the coiling hubs, the coil support would define this circumference and diameter. When a plurality of coil supports is provided for any one or more of the coiling hubs, the plurality of coil supports would define this circumference and diameter. For example, the plurality of coil supports may be arranged in a circular configuration.

The coiling position may be a position along the indexing path at which the coiling hub axis of any one of the coiling hubs and the coiling axis would be co-axial. Preferably, the coiling axis, or a projection thereof, intersects or is at least incident on the indexing path, preferably substantially perpendicularly so.

The device may also include a holding member applicator device. The holding member applicator device may be capable of applying and may therefore be arranged to apply, in use, a holding member to a shock tube coil that has been coiled onto the coil support of any one of the coiling hubs when the coiling hub is located at a holding member application position along the indexing path. The holding member may be such that, when applied to the shock tube coil in use, it holds the shock tube coil in its coiled configuration independently of the coiling device. More specifically, the holding member may be of a type that loops around plurality of coiled sections of the shock tube coil, thereby holding the coiled sections together and retaining the shock tube coil in its coiled configuration. The loop may, in particular, be provided by a length of adhesive tape. In such a case, the holding member applicator device may be a taping device and the holding member applicator position may be a taping position.

The coiling device may also include a shock tube coil discharging member which is displaceably mounted in the coiling device to discharge, by way of its displacement in use, shock tube that has been coiled onto the coil support of any one of the coiling hubs from the coiling hub when the coiling hub is located at a shock tube coil discharge position along the indexing path. Preferably, the discharging member is a discharging piston. The discharging piston would typically be arranged for displacement in a direction substantially parallel with the coiling axis of the coiling hubs at a point along the shock tube coil at which it would, in use, discharge the shock tube coil carried by any one of the coiling hubs from the coiling hub by physically pushing the shock tube coil off from the coiling hub.

The shock tube coiling position, the holding member application position and the shock tube coil discharge position may follow each other in that sequence along the indexing path in the operating direction. More particularly, the shock tube coiling position, the holding member application position and the shock tube coil discharge position may be located along the indexing path at respective positions which are angularly spaced from each other about the indexing axis. It will be appreciated that these positions are positions along the indexing path at which coiling, holding member application and discharge respectively occurs. The determination of a particular position as the coiling, holding member application or discharge position is therefore made with reference to whether or not coiling, holding member application or discharge can operatively occur at that position in the manner described herein. The angular spacings between the positions may be equal to the angular spacings between the coiling hubs such that when one coiling hub is in the coiling position, the other coiling hubs are, respectively, at the holding member application position and at the shock tube coil discharge position.

The coiling member at the coiling positing may comprise a coiling arm. The coiling arm may extend substantially parallel to and be radially spaced from the coiling axis. The radial spacing between the coiling arm and the coiling axis may be greater than the radii of the coiling hubs. Accordingly the coiling path would have a larger diameter and circumference than the coiling hubs. By this configuration, the coiling arm is rendered capable of moving circumferentially around the coiling hub and of coiling shock tube about and onto the circumference of the coiling hub, or of its one or plurality of coil support members, in use, thereby to provide a shock tube coil on the coiling hub. The coiling arm may also be mounted for axial displacement relative to the coiling axis. Such axial displaceability may be for the coiling arm to retreat axially in a direction away from the coiling hub, thereby to arrange respective coils of a particular shock tube coil that is coiled on the coiling hub adjacent to and not overlaying each other.

It will be appreciated that when any one of the coiling hubs leaves the coiling position, in use, it would carry an associated shock tube coil with it. Displacement of the coiling hub support member about the indexing axis may therefore locate the coiling hubs, sequentially and individually, respectively in the coiling, holding member application and discharge positions. In other words, along the displacement path each coiling hub may be sequentially locatable to occupy the coiling position, then the holding member application position, and finally the ejection position, before returning to the coiling position. At all times when one of the coiling hubs occupies one of the positions, the other coiling hubs will occupy, respectively, the remaining positions.

The device may include a shock tube cutting device which is arranged to cut shock tube that extends, in use, between and therefore connects respective shock tube coils carried on two of the coiling hubs. Particularly, the cutting device may be arranged to cut shock tube that extends, in use, between two coiling hubs when those coiling hubs are located at the holding member application and discharge positions respectively, thereby to separate the respective shock tube coils from each other in use.

It is to be noted that, preferably, no cutting of the shock tube takes place between the coiling position and the holding member application position in use. In other words, in use, when coiling starts on a 'second' coiling hub following coiling on a 'first' coiling hub, the shock tube coil on the 'first' coiling hub would typically still be connected to the shock tube coil of the 'second' coiling hub, typically by a 'first' length of intermediate shock tube that extends between the two coiling hubs. Similarly, whilst the 'first' coiling hub is displaced into the discharging position and the 'second' coiling hub into the holding member application position, with coiling thus starting at the coiling position on a 'third' coiling hub, the shock tube coils on the 'first' and 'second' coiling hubs will still be connected by the 'first' length of intermediate shock tube, with the coils carried on the 'second' and 'third' coiling hubs thus also being connected to each other by a 'second' length of intermediate shock tube. In order for discharge of a discrete shock tube coil to occur at the discharging position, the cutting device is provided.

The coiling device may also include a displaceable retaining member, preferably one for each coiling hub, which is displaceable into a retaining position to retain, in use, a shock tube coil that has been coiled about and onto any one of the coiling hubs, on the coiling hub by clamping the shock tube coil between itself and the one or more coil support members of the associated coiling hub. The retaining member may therefore be displaceably mounted for displacement between a clamping, or retaining, position in which it, in use, clamps the shock tube coil between itself and the one or more coil support members of the associated coiling hub, and a release position. The clamping member may, in particular, be arranged such that it automatically assumes the retaining position after a shock tube coil has been coiled about and onto its associated coiling hub at the coiling position, and that it assumes the release position for the shock tube coil to be discharged at the discharge position. Preferably, the clamping member therefore remains in the retaining position between the coiling position and the discharge position, or at least until shortly ahead of the discharge position, e.g. until when its associated coiling hub is moved out of the holding member application position toward the discharge position. In one embodiment of the invention, the clamping member may be urged into the retaining position by a resilient force, exerted by a resilient member such as a spring or the like. Displacement of the clamping member into the release position against the resilient force may then be achieved by way of the abutment of one end thereof against a cam surface, which is included in the device, the shape of which is such that it urges the clamping member against the resilient force into the release position at least at the coiling and discharge positions.

IN ACCORDANCE WITH ANOTHER ASPECT OF THE INVENTION, there is provided a method of producing, from a bulk length of shock tube, shock tube coils comprising discrete lengths of shock tube, the method including

in a first coiling step, coiling, at a coiling position defining a coiling axis, shock tube about one or more coil support members of a first of at least three coiling hubs, thereby providing a first shock tube coil carried by the first coiling hub;

in a first displacement step, displacing, in an operating direction, the first coiling hub into a second, holding member application position and thereby displacing a second of the at least three coiling hubs into the coiling position;

in a first holding member application step, applying a holding member to the first shock tube coil in its coiled configuration such that the holding member independently holds the first shock tube coil in its coiled configuration;

in a second coiling step, effected simultaneously with the first holding member application step, coiling, at the coiling position, shock tube about and onto the one or more coil support members of the second of the at least three coiling hubs, thereby providing a second shock tube coil carried by the second coiling hub;

in a second displacement step, displacing, in the operating direction, the first coiling hub into a third, shock tube coil discharge position, thereby displacing the second coiling hub into the holding member application position and also thereby displacing a third of the at least three coiling hubs into the coiling position;

in a first shock tube coil discharge step, discharging the first shock tube coil from the first coiling hub;

in a second holding member application step, effected simultaneously with the first shock tube coil discharge step, applying a holding member to the second shock tube coil in its coiled configuration such that the holding member independently holds the second shock tube coil in its coiled configuration; and

in a third coiling step, effected simultaneously with the first shock tube coil discharge step and the second holding member application step, coiling, at the coiling position, shock tube about the one or more coil support members of the third of the at least three coiling hubs, thereby providing a third shock tube coil carried by third coiling hub,

wherein the coiling position, the holding member application position and the shock tube coil discharge position follow each other in the operative direction along an endless indexing path defined about and radially spaced from an indexing axis, along which path and about which axis the displacement steps are effected.

It should be noted that "first", "second" and "third" are used above to indicate the ranking sequence of the method steps relative to each other and not necessarily their ranking relative to other similar steps that may precede or succeed these steps.

The method may also include, in the shock tube coil discharge step, severing shock tube of the first shock tube coil from shock tube of the second shock tube coil before discharging the shock tube coil from its associated coiling hub which carries it.

In order to provide a plurality of shock tube coils, the method may continue for the second coiling hub to be displaced into the discharge position for the second shock tube coil to be ejected from the second coiling hub, with the third coiling hub thereby being displaced to the holding member application position for the third shock tube coil to be held in its coiled configuration, and with the first coiling hub thereby being returned to the coiling position for fresh shock tube to be coiled about it and a fourth shock tube coil to be provided. A similar repetitive situation would necessarily apply to the second and third coiling hubs for fifth, sixth etc shock tube coils to be provided, held and eventually ejected.

The method may particularly be performed by a coiling device as hereinbefore described.

Preferably, only three coiling hubs are provided in the group of coiling hubs. The coiling steps may be carried out for predetermined coiling periods. The displacement steps may be carried out for predetermined displacement periods. The coiling periods may each be about 1 .6 seconds in length, The displacement periods may each be about 0.8 seconds in length.

The coiling periods and displacement periods may overlap during displacement commencing / coiling ending transition periods and/or coiling commencing / displacement ending transition periods. The transition periods may each be about 0.2 seconds in length. Preferably, both the displacement commencing / coiling ending transition periods and the coiling commencing / displacement ending transition periods are carried out. Coiling the shock tube about the one or more coil support members of any of the coiling hubs when located at the coiling position in the coiling step may be effected by means of a rotatable shock tube coiling member which is, during the coiling steps, rotated about the coiling axis along a coiling path and which feeds shock tube onto the one or more coil support members of the respective coiling hubs. Displacement of the coiling hubs along the indexing path may be effected by means of a rotatable coiling hub support member which defines the indexing axis and on which the coiling hubs are arranged, the rotatable coiling hub support member being rotated about the indexing axis in the operating direction during the displacement steps, thereby displacing the coiling hubs along the indexing path. In such a case, the method may include, during the displacement commencing / coiling ending transition period, increasing the rotary speed of the rotatable coiling hub support member while decreasing the rotary speed of the coiling member. The method may also include, during the coiling commencing / displacement ending transition period, increasing the rotary speed of the coiling member while decreasing the rotary speed of the rotatable coiling hub support member. Such respective increases and decreases may be driven and controlled by respective servo motors.

BRIEF DESCRIPTION OF THE DRAWINGS

THE INVENTION WILL NOW BE DESCRIBED IN MORE DETAIL, with reference to the accompanying drawings, in which

FIGURE 1 shows, in three-dimensional view, a shock tube coiling device in accordance with the invention;

FIGURE 2 shows one side view of the coiling device of Figure 1 ;

FIGURE 3 shows another side view of the coiling device of Figure 1 , opposite to the side view shown in Figure 2;

FIGURE 4 shows an end view of the coiling device of Figure 1 ; FIGURE 5 shows another end view of the coiling device of Figure 1 , opposite to the end view shown in Figure 4;

FIGURE 6 shows a top view of the coiling device of Figure 1 ;

FIGURE 7 shows, in three dimensional view, a coiling hub support member of the coiling device of Figure 1 in a first position;

FIGURE 8 shows, in three dimensional view, the coiling hub support member of Figure 7 in a second position;

FIGURE 9 shows, in three dimensional view, the coiling hub support member of Figures 7 and 8 in a third position

FIGURE 10 shows, in three dimensional view, another coiling device in accordance with the invention; and

FIGURE 1 1 shows, in front view, a cam member of the coiling device of Figure

10. DETAILED DESCRIPTION OF THE INVENTION

REFERRING TO THE DRAWINGS and in particular to Figures 1 through 6, reference numeral 10 generally indicates a shock tube coiling device according to the invention. The coiling device 10 produces, in use, a plurality of shock tube coils of discrete length from a bulk length of shock tube.

The coiling device 10 includes a rotatable shock tube coiling hub support member 12. The support member 12 comprises a plate and has an operatively front face 12A, which is flat, and an operatively rear face 12B, which is also flat. The plate has a roughly triangular outline with rounded corners.

The coiling device 10 further includes a supporting frame 14. The support member 12 is rotatably mounted to the frame 14, defining an indexing axis 'A' about which the support member 12 can be rotated. It will be understood that the indexing axis can evenly said to be defined by the support member 12 when it is rotatably mounted to the frame 14.

With reference also to Figure 7, the support member 12 has a group of three coiling hubs 13A, 13B, 13C (jointly referred to by reference numeral 13) about which shock tube coils can, in use, be formed. Each coiling hub 13 comprises a circular arrangement of coil support members in the form of six elongate cylindrical coiling hub pins 15, with each coiling hub 13 therefore having a circular outer circumference. The circumference is 500mm in each case. The pins 15 project operatively forwardly from the front face 12A of the support member 12. The radii (and therefore also the diameter) of the circular arrangements of coiling hub pins 15 providing each coiling hub 13 are also equal in length.

Each of the coiling hubs 13 defines its own coiling hub axis, respectively designated as D1 , D2, D3 (jointly referred to as D). The coiling hubs 13 are arranged on the support member 12 such that their coiling hub axes D are equiangularly spaced from each other about the indexing axis A, i.e. at 120°, and are also equidistally spaced from the indexing axis A along respective radii thereof. The coiling hub axes D are all located on a circular path, being an indexing path T, about the indexing axis A, along which path I the axes D travel when the support member 12 is rotated about the indexing axis A.

Rotation of the support member 12 is driven by a first servo-motor 16. The first servo- motor 16 is operatively connected to the support member 12 by means of a gearbox 18. The gearbox 18 is also mounted to the frame 14.

The coiling device 10 further includes a shock tube coiling member comprising a shock tube coiling arm 20. The coiling arm 20 is rotatably mounted to the frame 14 to rotate along a circular coiling path about a coiling axis 'B' which is incident, perpendicularly, on the indexing path I. Rotation of the coiling arm 20 is driven, in use, by a second servomotor 22 which is also mounted to the frame 14.

The coiling arm 20 comprises a shock tube input-portion 20a and a shock tube output- portion 20b. Shock tube that is, in use, to be coiled onto the coiling hubs 13 of the support member 12, is fed to the coiling arm 20 through an input end 20c thereof, is passed along the input portion 20a and output portion 20b, leading from an output end 20d of the coiling arm 20 onto any one of the coiling hubs 13 so as to be coiled about and onto the coil support members of the coiling hub 13A, 13B or 13C by rotation of the coiling arm 20 about the coiling axis B when the coiling hub 13A, 13B or 13C is at a position along the indexing path I for such coiling to take place. This position is hereinafter referred to as a 'coiling position' and is at a location along the indexing path I at which the hub axis D of any one of the coiling hubs 13 is co-axial with the coiling axis B.

The input portion 20a of the coiling arm 20 is co-axial with the coiling axis B. The output portion 20b is radially spaced from the coiling axis B, with the output portion 20b therefore being able of travelling, by rotation of the coiling arm 20 about the coiling axis 'B', along a circular path, being the coiling path (not illustrated), having the coiling axis 'B' as its midpoint. Radial spacing of the output portion 20B from the coiling axis B is such that the coiling path has a radius greater than the radii of the coiling hub pin arrangements that provide the coiling hubs 13. Further, the location of the coiling path along the coiling axis B is such that it surrounds the coiling hubs 13, respectively, when they are located at the coiling position. By way of this configuration, feeding and coiling of shock tube about and onto the outer circumferences of the coiling hubs 13 by rotation of the coiling arm is enabled. Of course, it may be required, at start-up, for a free end of the bulk length of shock tube, that is to be formed into discrete coils, leading from the output portion 20B of the coiling arm 20 to be secured, in use, such that rotation of the coiling arm 20 about the coiling axis B along the coiling path causes, as rotation continues, shock tube to be drawn along and from the coiling arm 20, onto the coiling hub 13 that is in the coiling position at that moment.

For shock tube to be drawn, in use, smoothly along the coiling arm 20, the coiling arm 20 has leading pulley wheels 21 provided along its length. In use, shock tube leads in an axial feeding direction with respect to the coiling axis B, from the input end 20C of the coiling arms 20, along the input and output portions 20A, 20B, thereby leading around the pulley wheels 21 , toward an output end 20D of the coiling arm 20. Additionally, at the output end 20D of the coiling arm 20, the coiling arm 20 has an output pulley wheel 23, which is oriented substantially perpendicularly with respect to the leading pulley wheels 21 . The output pulley wheel 23 serves to change the direction of shock tube output from the coiling arm 20 to an output direction that is perpendicular to the axial feeding direction in which the shock tube was lead along the input and output portions 20A, 20B. Output of shock tube from the coiling arm in this manner 20 facilitates smooth coiling of shock tube about the coiling hubs 13. The pulleys are of diameter so as to avoid damage to the shock tube, in use, due to winding/bending the shock tube too tightly. The coiling device 10 further includes a shock tube holding member applicator in the form of an adhesive tape applicator 24 which is capable of applying adhesive tape as the holding member described in accordance with the invention. Whilst described as a tape applicator 24, the applicator 24 may, as one alternative, be a label applicator to apply an adhesive label. The applicator 24 is also mounted on the frame 14 and is configured to apply adhesive tape to a shock tube coil that has been provided on any one of the coiling hubs 13 when such a coiling hub is at a position about the indexing axis for such application to take place. This position is hereinafter referred to as a 'holding member application position'. The application of the adhesive tape serves, in use, to secure, or hold, a shock tube coil to which it is applied in its coiled configuration independently of the coiling device 10. The coiling device 10 further includes two shock tube coil discharging, or ejecting, pistons, 26a, 26b which are axially displaceable along ejecting axes Ό1 ', 'C2' through associated apertures 27 that are defined in the support member 12 at each coiling hub (see Figures 7 through 9). The pistons 26a, 26b are, in use, in axial register with these apertures 27 when any one of the coiling hubs 13 is at a position about the coiling axis for such displacement through the apertures to take place. This position is hereinafter referred to as a 'shock tube coil discharge position', or merely as a 'discharge position'. In use, axial displacement of the ejecting pistons 26a, 26b through the apertures 27 serves to eject, from any one of the coiling hubs 13 when located at the coiling position, a shock tube coil that is carried on such a coiling hub 13 in use.

When one of the coiling hubs 13A, 13B or 13C is at the coiling position, the others will, respectively, be at the holding member application position and at the discharge position.

Although not illustrated in the figures, the coiling device 10 also includes a shock tube cutting device that is arranged on the frame 14 to cut shock tube that extends, in use, between adjacent coiling hubs 13 when such coiling hubs 13 are located respectively in the securing and discharge positions, thereby to allow for a shock tube coil carried by any one of the coiling hubs 13 that is in the discharge position to be freely ejected from that coiling hub 13. Typically, the cutting device has an axially displaceable cutting edge that is so axially displaceable along a cutting axis that is incident on the support member 12 between the securing and discharge positions, but not necessarily on the indexing path I.

The coiling device 10 further includes three pivotally displaceable shock tube coil retaining members 17a, 17b, 17c (commonly referred to by way of reference numeral 17), one being provided for each coiling hub 13. Each retaining member 17 is elongate, being pivotally mounted to the support member 12, at a pivot point along its length, adjacent to one of the coiling hub pins 15 of each coiling hub 13. The coiling hub pins 15 adjacent to which the respective retaining members 17 are mounted are hereinafter designated by reference numerals 15A, 15B and 15C, respectively being associated with the retaining members 17A, 17B and 17C. The retaining members 17A, 17B, 17C are, in turn, respectively associated with the coiling hubs 13A, 13B, 13C. By way of their pivotal mounting, each retaining member 17 is pivotally displaceable between a clamping, or retaining configuration and a release configuration. The clamping configuration is illustrated. In the clamping configuration, each retaining member 17 extends substantially parallel to the coiling hub pin 15 adjacent to which it is pivotally mounted, thus having an operatively front portion, which projects beyond the front face 12A of the support member 12, and an operatively rear portion, which projects beyond the rear face 12B of the support member 12. With respect to a radius of the hub axis D of their associated coiling hubs 13, radial spacings between the retaining members 17 and their associated coiling hub pins 15, when in the retaining configuration, are such that a shock tube coil that is carried on any one of the coiling hubs 13 will be located between the retaining member 17, associated with the particular coiling hub 13, and its associated coiling hub pin 15, such that the shock tube coil is clamped against associated coiling hub pin 15, with the shock tube coil thereby being retained on the coiling hub 13. Such clamping retention is preferred particularly when a shock tube coil has been formed about one of the coiling hubs 13 at the coiling position and is then carried on the concerned coiling hub 13 between the coiling position, the holding member application position and the discharge position.

In the release configuration, or position, the retaining members 17 are, respectively, angularly displaced from their positions in their retaining configurations, thereby releasing shock tube coils that are carried on their associated coiling hubs 13. In the release configuration, the retaining members 17 are angularly, and eventually substantially perpendicularly, oriented relative to their orientation in the retaining configuration. The retaining members assume the release configuration at least at the discharge position and the coiling position. Thus, a shock tube coil that is carried on a particular coiling hub 13 can be ejected therefrom at the discharge position, and a new shock tube coil can be formed on an emptied/empty coiling hub 13 at the coiling position.

The retaining members 17 are urged in a biasing manner into the retaining configuration by respective resilient members, comprising springs (not illustrated). Displacement of the retaining members 17 into the release configuration from the biased retaining configuration occurs by reason of rotational displacement of the support member 12. More particularly, a cam member 102 (not shown for the coiling device 10, but shown in the embodiment 100 of the coiling device of the invention illustrated in Figure 10; see also Figure 1 1 ) providing a cam surface is provided in the coiling device 10, being mounted to the frame 14 operatively behind and axially spaced from the rear surface 12B of the support member 12, such that rear portions of each retaining member 17 abuts the cam surface at locations along the indexing path I at which the retaining members 17 are required to be in the release configuration, which abutment urges the retaining members 17 against the resilient force exerted by the springs, into the release configuration. The locations along the indexing path I at which displacement of the retaining members 17 into the release configurations occurs are, in particular, at the coiling position and at the discharge position, respectively to allow the forming of a shock tube coil about a particular coiling hub 13, when located at the coiling position, and to allow the ejection of a shock tube coil carried on a particular coiling hub 13, when located at the discharge position.

Referring now, in particular, to Figures 7 through 9, operation of the coiling device 10 will be described with reference to the support member 12 and its movement use.

In order for shock tube to be coiled about the coiling hub 13A, the coiling hub 13A is located in the coiling position.

It is to be noted that the support member 12, and the coiling device 10 for that matter, is configured such that whilst coiling of shock tube occurs at the coiling position, the application of adhesive tape at the holding member application position and the ejection of a secured shock tube coil at the discharge position can occur substantially simultaneously. For this to occur, the coiling device 10 is configured such that when one of the coiling hubs, e.g. 13A is at the coiling position, the other two hubs 13B, 13C are, respectively, at the securing and discharge positions. Accordingly, the coiling device 10 is configured insofar the location of the adhesive tape applicator 24, the ejecting cylinders 26a, 26b and the non-illustrated cutter are concerned, such that when one of the coiling hubs 13 is in the coiling position, adhesive tape application and ejection can be effected at the respective locations of the other two coiling hubs 13. It will be appreciated, based on the configuration of the support member 12 and of the coiling hubs 13 thereon, that the coiling position, holding member application position and discharge position are therefore spaced from each other and from the indexing axis A in substantially the same manner in which the coiling hubs 13 are spaced from each other and from the indexing axis A. Ejection would, preferably, follow taping, and therefore the discharge position succeeds, i.e. is located after, the holding member application position along the indexing path I. With reference to Figure 7 therefore, the coiling hub 13A is in the coiling position, the coiling hub 13B is in the holding member application position, and coiling hub 13C is in the discharge position.

In use, a first shock tube coil will, in the presently illustrated case, be formed about the coiling hub 13A by means of the coiling arm 20. More particularly, the coiling arm 20 rotates about the coiling axis "B" in a clockwise direction such that the output portion 20B of the coiling arm 20 moves about a circumference of the coiling hub 13A whilst feeding shock tube onto the coiling hub 13A and thereby forming the first shock tube coil on the coiling hub 13A. Since no shock tube coil has, as yet, been formed on either of the coiling hubs 13B, 13C in the exemplified embodiment, no functional operation yet occurs at either the securing or discharge positions.

Once a required length of shock tube has been coiled about the coiling hub 13A, the support member 12 is displaced about the indexing axis in an anti-clockwise direction, thereby moving the coiling hub 13A along the indexing path I into the holding member application position where the coiling hub 13B was previously located. It will be appreciated that, angularly about the indexing axis, the angular displacement of the support member 12 will be substantially equal to the angular spacing between the coiling hubs 13 about the indexing axis, i.e. 120°. It is envisaged that anti-clockwise displacement of the support member 12 would be synchronised with the clockwise displacement of the coiling arm 20 at commencement and/or at completion of coiling of any particular shock tube coil at the coiling position, with coiling arm rotation speed being decreased and support rotation speed being increased complementally. There may therefore be a transition period before a particular coiling hub 13 arrives at and/or after a coiling hub 13 leaves the coiling position during which coiling continues. In this manner, it is expected that a smooth switch of coiling hubs 13 between coiling, securing and discharge positions can be achieved, whilst also saving operational time, considering that switching can commence sooner than when discrete operational intervals are used. The coiling, securing and ejecting operations therefore run more smoothly when following such an approach. Also, importantly, by effecting continuous motion of the support member 12, continuous feeding of shock tube in use can be maintained with it being possible to draw shock tube continuously from a, typically stationary, reel thereof even whilst the support member 12 is indexing, such that shock tube feeding by reel rotation is avoided. In the applicant's experience feeding shock tube by means of reel rotation typically requires discrete or intermittent reel rotation operations interposed with periods of reel stoppage between coiling operations. This is avoided by the construction of the coiling device 10 of the present invention. With the coiling hub 13A being moved into the holding member application position and the coiling hub 13B being moved into the discharge position, the coiling hub 13C is moved into the coiling position, with its axis D3 being brought into substantial co-axial alignment with the coiling axis B. The coiling arm 20 then forms a second shock tube coil on the coiling hub 13C by coiling shock tube about the coiling hub 13C in the same manner as was done in the case of coiling hub 13A. Whilst this occurs, the adhesive tape applicator 24 applies adhesive tape about the first shock tube coil that is still on the coiling hub 13A that is in the holding member application position.

It is to be appreciated that no cutting operation takes place between the coiling position and the holding member application position. Accordingly, the first shock tube coil that is on the coiling hub 13A whilst it is at the holding member application position and the second shock tube coil that is being formed on the coiling hub 13C are connected by a first intermediate length of shock tube. It is this length that will be cut by the non- illustrated cutter, in the manner hereinafter described.

Once the required length of shock tube has been coiled on the coiling hub 13C, the support member 12 is again displaced in an anti-clockwise direction through 120°, thereby moving the coiling hub 13A into the discharge position, moving the coiling hub 13C into the holding member application position, and moving the coiling hub 13B into the coiling position. Once again it is pointed out that the second shock tube coil that has been formed on coiling hub 13C, which is now in the discharge position, and the first shock tube coil that is on coiling hub 13A, which is now in the holding member application position, are still connected by the first intermediate length of shock tube. In order for the first shock tube coil to be ejected from the coiling hub 13A, the cutter, through axial displacement of its cutting edge, cuts the first intermediate length of shock tube, typically mid-way between the securing and discharge positions, whereafter the first shock tube coil, that has now been separated from the second shock tube coil, is ejected from the coiling hub 13A by axial displacement of the ejecting pistons 26a, 26b, which effectively 'bump' the first shock tube coil off the hub 13A. Whilst this occurs, adhesive tape is applied to the second shock tube coil by the adhesive tape applicator 24 at the holding member application position, and a third shock tube coil is formed on the coiling hub 13B which is, at this stage, located in the coiling position.

In producing a plurality of shock tube coils, the abovementioned process continues with the coiling hub 13A being returned to the coiling position whilst the second shock tube coil is being ejected at the discharge position from coiling hub 13B (after having been separated, by means of the cutter, from the third shock tube coil that was coiled onto the coiling hub 13B and to which it would have been connected by a second intermediate length of shock tube) and whilst the third shock tube coil that was coiled onto coiling hub 13B is being secured by the application of adhesive tape to it at the holding member application position.

Referring to Figure 10, reference numeral 100 indicates another embodiment of a coiler in accordance with the invention. The coiling device 100 is, in structure and operation, substantially identical to the coiling device 10 and parts shared by the two coilers 10, 100 that are of relevance to the description of the cam member 102 that is to follow are therefore indicated by the same reference numerals. It is to be noted that the adhesive tape applicator 24 is not shown, and neither is the cutting device, both of which would normally be included in the coiling device 100. The coiling device 100 also has servo motors 16.1 , 22.1 which are of a different model and make than those shown in the coiling device 10. Importantly, the coiling device 100 includes the cam member 102 hereinbefore described. The location and operation of the cam member 102 is also as is hereinbefore described. Figure 1 1 shows the cam member 102 in front view, with the locations of the coiling hubs 13A, 13B, 13C, as they are shown in Figure 10, being illustrated for reference purposes. Whilst the support member 12 is capable of moving about the indexing axis A, the cam member 102 is fixed in the illustrated position, being co-axial with the indexing axis A. The cam member 102 defines a cam surface between 104 and 106 which has curved portions defining have apexes that project radially inwardly relative to the indexing axis A. In use in their clamping configuration, rear ends of the clamping members 17 travel along a clamping member path. Along the path, the rear ends of the clamping members 17 do not come into contact with the cam 102, except at the cam surface in the manner hereinafter described. The cam surface breaks the path such that the rear ends of the clamping members abuts these curved portions of the cam surface, with the clamping members 17 as a result being pivotally displaced against the resilient force that urges them into the clamping configuration, thereby to assume their release configurations when in contact with the apexes of the curved portions of the cam surface. Taking into account the locations of the coiling hubs and the configuration of the coiling, securing and discharge positions as hereinbefore described, it will be appreciated that the clamping members 17 assume their release configurations at the coiling position and at the discharge position. The invention is not limited to the configuration of the cam member illustrated in the drawings. Other configurations may include one in which the cam surface is axially defined and not radially as is presently illustrated. In such a case, the clamping members 17 would of course be adapted accordingly.

In a trial run conducted with an experimental model of the coiling device according to the invention, in which a coiling operation according to the method of the invention was carried out, operating matrices represented in Tables 1 to 3 below were compiled. These operating matrices relate to a discrete time period during continuous operation of the coiling device 10 which is designated as starting at time 0. Only selected operations are described.

Table 1 : From rest to end of first indexing (displacement) step

Table 2: From end of first indexin dis lacement ste to end of second indexin dis lacement ste

Table 3: From end of second indexing (displacemer t) step to e nd of third inc texing (disp acement) step

It will be appreciated that references hereinbefore and hereinafter to the coiling step, the displacement step, the holding member application step and the discharge step are to the steps of the method of the invention. Similarly, the reference numerals which appear in brackets in the tables above refer to the components of the shock tube coiling device 10 illustrated in the accompanying drawings which would typically be involved in carrying out the respective method steps. Accordingly, the contents of the tables above are discussed with reference to the steps of the method of the invention and with reference to the relevant components of the coiling device 10. This should, however, not be regarded as limiting the invention to the specific coiler configuration or specific method. The coiling operation commences at time 0 seconds with the coiling hub support member 12 decelerating, to rest, from a displacement step preceding the first displacement step hereinafter described and with the coiling arm 20 accelerating, from rest, in a first coiling step as hereinafter described. It is to be noted at this point that the use of "first", "second" and "third" is merely for indicating sequence of the concerned features relative to one another and not necessarily relative to the exemplified coiling operation as a whole.

In a first coiling step, at the coiling position, shock tube is coiled about the coiling hub 13A, which occupies the coiling position. At this point, the coiling hub 13B is at the holding member application position and the coiling hub 13C is at the discharge position.

Coiling of shock tube is done by feeding shock tube about and onto the coiling hub pins 15 of the coiling hub 13A from the coiling arm 20 and by rotating the coiling arm 20 about the coiling axis B, in the manner hereinafter described, over a first coiling period. In this manner, a first shock tube coil, carried by the first coiling hub, is provided.

As is seen from Table 1 , the first coiling period commences when the coiling arm 20 is ramped-up (accelerated) to full rotational speed over a first coiling commencement (acceleration) period of 0.2 seconds. The coiling arm 20 is then run at full speed over a first full speed coiling period of 1 .2 seconds, and is subsequently ramped-down (decelerated) to rest over a first coiling ending (deceleration) period of 0.2 seconds. The full first coiling period therefore spans 1 .6 seconds, including the first coiling commencement, first full speed coiling and first coiling ending periods.

Commencement of a first displacement step, which spans a first displacement period, coincides with commencement of the first coiling ending period. In the first displacement step, the support member 12 is ramped-up to full rotational speed over a first displacement commencing period of 0.2 seconds which is concurrent with the first coiling ending period. Since the first coiling ending and first displacement commencing periods are concurrent, the period of overlap is regarded as a coiling ending / displacement commencing transition period of the first coiling and first displacement steps.

After the first displacement commencement period, rotation of the support member 12 is run at full speed over a first full speed displacement period of 0.4 seconds. Thereafter, rotation of the support member 12 is ramped-down to rest over a first displacement ending period of 0.2 seconds. The first displacement period therefore spans 0.8 seconds, including the first displacement commencement, first full speed displacement and first displacement ending periods.

During the first displacement commencing period, by reason of the displacement of the support member 12, the clamping member 17A begins to move into its retaining, or clamping, configuration. It completes this movement by the end of the first displacement commencing period, thereby clamping the shock tube coil is carried by the coiling hub 13A to the coiling hub 13A. By the end of the first displacement period, the coiling hub 13C has been moved into the coiling position for shock tube to be coiled about and onto it in a second coiling step effected over a second coiling period. The second coiling step commences before completion of the first displacement step, however. More particularly, commencement of the second coiling step coincides with commencement of the first displacement ending period. The second coiling step commences with ramping-up the coiling arm 20 to full rotational speed over a second coiling commencing period of 0.2 seconds which is concurrent with the first displacement ending period. Since the first displacement ending and second coiling commencing periods are concurrent, the period of overlap is regarded as a displacement ending / coiling commencing transition period of the first displacement and second coiling steps.

From the end of the second coiling commencing period, the coiling arm is again run at full speed over a second full speed coiling period of 1 .2 seconds and is thereafter ramped-down over a second coiling ending period of 0.2 seconds. By the end of the second coiling period, a second shock tube coil has been coiled about and is therefore carried by the coiling hub 13C.

Also by the end of the first displacement period, the coiling hub 13A has been displaced into the holding member application position. During the currency of the second full speed coiling period, with the coiling hub 13A and the first shock tube coil being in the holding member application position, adhesive tape is applied to a plurality of coiled sections of the second shock tube coil by means of the applicator 24, thereby to hold those sections of the first shock tube coil together and also hold the first shock tube coil in its coiled configuration.

Commencement of a second displacement step, which spans a second displacement period, coincides with commencement of the second coiling ending period. In the second displacement step, the support member 12 is ramped-up to full rotational speed over a second displacement commencing period of 0.2 seconds which is concurrent with the second coiling ending period. Since the second coiling ending and second displacement commencing periods are concurrent, the period of overlap is also regarded as a coiling ending / displacement commencing transition period of the first coiling and first displacement steps.

Upon completion of the second displacement commencement period, rotation of the support member 12 is run at full speed over a second full speed displacement period of 0.4 seconds. Thereafter, rotation of the support member 12 is ramped-down to rest over a second displacement ending period of 0.2 seconds. The second displacement period therefore also spans 0.8 seconds, including the second displacement commencement, second full speed displacement and second displacement ending periods.

During the second displacement commencing period, by reason of the displacement of the support member 12, the clamping member 17C begins to move into its retaining, or clamping, configuration. It completes this movement by the end of the second displacement commencing period, thereby clamping the second shock tube coil which is carried by the coiling hub 13C to the coiling hub 13C.

By the end of the second displacement period, the coiling hub 13A has been moved into the discharge position for the first shock tube coil to be discharged from it. During the currency of the third full speed coiling period, a length of shock tube connecting the first and second shock tube coils is severed by the cutting device and the first shock tube coil is discharged from the coiling hub 13A by displacement of the pistons 26A, 26B in the manner hereinbefore described.

Also by the end of the second displacement period, the coiling hub 13C has been displaced into the holding member application position. During the currency of the third full speed coiling period, with the coiling hub 13C and the second shock tube coil being in the holding member application position, adhesive tape is applied to a plurality of coiled sections of the second shock tube coil by means of the applicator 24, thereby to hold those sections of the second shock tube coil together and also hold the second shock tube coil in its coiled configuration.

Also by the end of the second displacement period, the coiling hub 13B has been moved into the coiling position for shock tube to be coiled about and onto it in a third coiling step effected over a third coiling period. The third coiling step commences before completion of the second displacement step, however. More particularly, commencement of the third coiling step coincides with commencement of the second displacement ending period. The third coiling step commences with ramping-up the coiling arm 20 to full rotational speed over a third coiling commencing period of 0.2 seconds which is concurrent with the second displacement ending period. Since the second displacement ending and third coiling commencing periods are concurrent, the period of overlap is also regarded as a displacement ending / coiling commencing transition period of the second displacement and third coiling steps.

From the end of the third coiling commencing period, the coiling arm is again run at full speed over a second full speed coiling period of 1 .2 seconds and is thereafter ramped- down over a second coiling ending period of 0.2 seconds. By the end of the third coiling period, a third shock tube coil has been coiled about and is therefore carried by the coiling hub 13B.

It is evident from the foregoing discussion that within a period of six seconds, the coiling device of the invention and coiling method of the invention allows for the production of a discrete shock tube coil that is taped and automatically discharged from the coiling device. Intervals between obtaining a first shock tube coil and subsequent shock tube coils particularly rapid. This is regarded as being a particular advantage of the invention which is enabled by the configuration and operation of the coiling device in the manner herein described.

The applicant has therefore found that the coiler according to the invention is effective in producing large numbers of taped shock tube coils within a relatively short timeframe and with minimal operator involvement.