HOSE RESTRAINT APPARATUS, SYSTEM AND METHOD
Field of the Invention
The present invention relates to a hose restraint apparatus, system and method and especially but not exclusively to a restraint apparatus, system and method for high pressure hoses.
Background
Flexible high pressure hoses are used in reverse circulation drill rigs to transport drill cuttings from the drill head to a desired destination. The hoses used in such applications are required to be flexible in order to accommodate the considerable, generally vertical, movement of the drill head during drilling. Typical hoses in such an application might have an outside diameter of approximately 4 inches (10cm) and an inside diameter of approximately 3 inches (7.5cm). Wear on the hoses, such as that caused by the passage of drill cuttings therethrough (especially where the hose is sharply curved to provide a change of direction), or increases in pressure due to blockages, may cause a hose used in such an application to rupture. Rapidly escaping high pressure fluid can cause a ruptured hose to snake rapidly and unpredictably, which can be extremely dangerous, and potentially lethal, to nearby workers. There is therefore a need to reduce the potential danger of wildly moving ruptured hoses. There may also be benefits in restraining hoses in other applications from undesirable movement due to expulsion of a fluid being conveyed by the hose.
Summary of the Invention
According to a first aspect of the present invention, there is provided a hose restraint apparatus comprising an elongate flexible member provided with at least three spaced apart attachment portions thereon for attaching the elongate flexible member to a hose. Preferably the attachment portions are for attaching the elongate flexible member to the outside of a hose.
Preferably the attachment portions are adapted to attach the elongate flexible member to a hose by means of fasteners. In one embodiment the fasteners comprise releasable fasteners.
In one embodiment the fasteners comprise threaded fasteners.
In one embodiment the fasteners comprise buckles or clips.
Preferably the elongate flexible member comprises a number of retaining portions for engaging with one or more complementary retainers, so that the elongate flexible member, and, in use, the hose to which it is attached, can be retained within a predetermined desired range of positions.
Preferably the elongate flexible member comprises a chain.
Preferably the chain comprises a number of chain links.
Preferably the chain links are pivotally connected. Preferably the chain links are pivotally connected about axes which are oriented substantially perpendicular to the direction of elongation of the chain.
Preferably the chain links are pivotally connected by connecting pins.
Preferably the connecting pins are oriented substantially perpendicular to the direction of elongation of the chain. Preferably the retaining portions comprise parts of links of the chain.
Preferably the retaining portions at least partially define recesses provided substantially between connecting pins of the chain.
Preferably the retaining portions are for engaging one or more complementary retainers in the form of chain guides or sprockets. The hose restraint apparatus may comprise more than one elongate flexible member, each provided with at least three spaced apart attachment portions thereon for attaching the respective elongate flexible member to a hose.
The hose restraint apparatus may comprise two elongate flexible members extending in side by side relationship and the attachment structures may be connected between the two elongate flexible members at said locations.
The attachment portions of the hose restraint apparatus may comprise attachment structures each connected to at least one elongate flexible member at spaced locations along that member and adapted to extend around and confine the hose at these locations.
The attachment structures may extend between the elongate flexible members to confine the hose at those locations.
An embodiment provides a hose restraint comprising a pair of elongate flexible members extending in side by side relationship such that a hose to be restrained can be disposed to extend along the restraint between the two elongate flexible members; and a plurality of attachment structures disposed at locations spaced along the restraint to extend between the elongate flexible members to confine the hose at those locations.
The hose attachment structures may confine the hose such that the elongate flexible members are at substantially diametrically opposed locations with respect to the hose.
The hose attachment structures may confine the hose such that the confinement allows some movement of the hose relative to the one or more flexible elongate members. This can allow a degree of play between the hose and the one or more elongate flexible members, which can be useful if the paths of the hose and the one or more elongate flexible members do not exactly correspond. In one such embodiment the hose attachment structures extend substantially around the hose, but do not tightly grip the hose, and may be regarded as hose confinement structures. Such hose confinement structures still function to attach the hose to the one or more elongate flexible members and are thus a type of hose attachment structure. It is preferred that in such embodiments the hose restraint apparatus is arranged to avoid the hose becoming inadvertently detached from the one or more elongate flexible members in the event of breakage of the hose even though the attachment structures do not tightly grip the hose. One such arrangement comprises providing hose confinement structures at a spacing which, taking into account the flexibility of the hose, is small enough that the hose cannot bend enough to work free from the confinement structures.
The hose attachment structures may comprise curved members to curve around the hose.
The elongate flexible members may be a pair of chains having link openings directed normal to directions extending between the chains whereby the chains can be supported on sprockets to curve in side by side relationship with a common curvature, and to opposite sides of a hose confined between them.
Each of the hose confinement structures may comprise a first curved member interconnected between the two chains to receive the hose and a - A - second curved member connectable to the first member such that the two members together encompass the hose.
In one embodiment the spaced apart attachment portions comprise attachment members provided on the elongate flexible member. In one embodiment the attachment portions are each configured to cradle an axially short section of a hose.
Preferably the attachment portions are adapted to extend around at least a part of the circumference of a hose.
In one embodiment the attachment portions are each adapted to facilitate attachment of a strap.
In one embodiment the attachment portions are each provided with at least one aperture therein to facilitate attachment of a strap.
In one embodiment the attachment portions are each provided with a strap adapted to secure a hose to the elongate flexible member. In one embodiment the attachment portions comprise one or more outwardly projecting attachment members.
Preferably each attachment portion comprises at least two attachment members.
In one embodiment each attachment portion comprises at least two substantially identical attachment members.
Preferably the attachment members are securely attached to the elongate flexible member.
Preferably the attachment members are securely attached to the chain.
Preferably the attachment members are securely attached to links of the chain.
In one embodiment at least some of the attachment members are integrally formed with parts of the elongate flexible member.
In one embodiment at least some of the attachment members are integrally formed with parts of links of the chain. In one embodiment at least some of the attachment members are each integrally formed with a side part of a link of the chain.
In one embodiment each of the attachment portions is adapted to extend around the circumference of a hose. The attachment portions may each comprise first and second attachment members, each having a first end proximal to the elongate flexible member and a second end distal from the elongate flexible member. The distal ends of the attachment members may comprises fastener portions adapted to fasten the distal ends together (and/or vary parameters of the fastening of the distal ends, such as the length) in order to secure a hose.
In some embodiments the elongate flexible member is in the form of a cable, preferably a metal cable. In some embodiments the elongate flexible member is in the form of a flexible belt. The belt may be provided with retaining portions, for engaging with one or more complementary retainers, which may be in the form of teeth.
According to a second aspect of the present invention there is provided a hose restraint system comprising: an elongate flexible member; a hose attached to the elongate flexible member, at spaced apart locations along its length; wherein the hose is restrained by its attachment, at spaced apart locations along its length, to the elongate flexible member. Preferably the hose is restrained such that, in the event that the hose breaks, the free end regions of the hose which are created by the break are restrained by the adjacent attachments of the hose to the elongate flexible member and the respective lengths of hose between the attachments and the free end regions. Preferably, the hose is restrained by its attachment at spaced apart locations along its length to the elongate flexible member, against movement in its radial direction.
Preferably the hose restraint system further comprises a first anchoring point for anchoring a first end portion of the elongate flexible member and a second end point for anchoring a second end portion of the elongate flexible member. At least one of the anchoring points may be moveable.
Preferably the hose restraint system further comprises at least one retainer for retaining a part of the elongate flexible member within a desired predetermined range of positions. Preferably at least one retainer is for guiding the elongate flexible member at a change of direction thereof.
The system may comprise a mechanism for moving the elongate flexible member within a predetermined range of positions.
The system may comprise two or more elongate flexible members. Preferably the elongate flexible member is provided with a plurality of spaced apart attachment portions thereon for attaching the elongate flexible member to the hose. Preferably the elongate flexible member has greater tensile strength than the hose.
Preferably the elongate flexible member is more durable than the hose. Preferably, the hose is restrained by its attachment, at spaced apart locations along its length to the elongate flexible member, against movement in its radial direction even if the hose breaks.
Preferably the elongate flexible member is provided with least three spaced apart attachment portions thereon for attaching the elongate flexible member to a hose. Preferably the elongate flexible member is provided with least three spaced apart attachment portions between the ends thereof for attaching the elongate flexible member to a hose.
Preferably at least a portion of the hose is attached to the flexible elongate member at at least three locations, wherein the spacing between any two adjacent locations of said at least three locations does not exceed 2.5 metres.
Preferably at least a portion of the hose is attached to the flexible elongate member at at least three locations, wherein the spacing between any two adjacent locations of said at least three locations does not exceed 1.5 metres.
Preferably at least a portion of the hose is attached to the flexible elongate member at at least three locations, wherein the spacing between any two adjacent locations of said at at least three locations does not exceed approximately one metre. In one embodiment the hose is a high-pressure hose. The hose may be adapted to convey a fluid pressurised to a pressure of at least three atmospheres. The hose may have an outside diameter of at least approximately 8cm (approximately 3inches). A typical hose included in the system has an inside diameter of approximately 8cm (approximately 3inches) and an outside diameter of approximately 10cm (approximately 4 inches) although, of course, other sizes of hose may be used.
In one embodiment the hose restraint system is incorporated in a drill rig. Preferably the elongate flexible member comprises an apparatus in accordance with the first aspect of the present invention. According to a third aspect of the present invention there is provided a method of restraining a hose comprising: attaching an elongate flexible member to the hose via at least three spaced apart attachment portions spaced apart along at least a portion of the length of the hose and/or elongate flexible member; and restraining the elongate flexible member to a desired position or range of positions. Preferably the method comprises use of an apparatus in accordance with the first aspect of the present invention.
Preferably the method comprises use of a system in accordance with the second aspect of the present invention.
According to a fourth aspect of the present invention there is provided a drill rig assembly, comprising: a mast; a drill head able to move along the mast; a hose attached at a first portion thereof to the drill head; an elongate flexible member, attached a number of locations along its length to the hose, and adapted to restrain the hose by virtue of its attachment thereto; and at least one retainer for retaining the flexible member so that it is restrained to one or more positions within a predetermined range of positions.
Preferably the elongate flexible member is attached at a first end thereof to the drill head.
Preferably the hose is for receiving from the drill head, and conveying away from the drill head, materials received from a drill string attached to the drill head.
Preferably the hose is attached at a second portion thereof to a point fixed relative to the drill rig.
Preferably the elongate flexible member is attached at a second end thereof to a point fixed relative to the drill rig.
Preferably the retainer is adapted to move in order to take up slack in the elongate member as the drill head moves. In an embodiment in which two elongate flexible members are provided, the retainer preferably comprises a first guided path for the first elongate flexible member and a second, substantially parallel, path for the second elongate flexible member.
Each of the guide paths may be provided by a plurality of sprockets. The sprockets of each guide path may be arranged in a curved path, to guide the respective elongate members along a curved path.
The curved paths of each guide paths are preferably substantially parallel.
The retainer may comprise a plurality of sprocket assemblies, each comprising at least two sprocket.
Each sprocket assembly may comprise at least two substantially coaxial sprockets.
The retainer preferably comprises at least one hose engaging guide for engaging and guiding part of the hose.
At least one hose engaging guide for engaging and guiding part of the hose may be provided as part of a sprocket assembly. At least one sprocket assembly preferably comprises at least one hose engaging guide provided between the sprockets of the sprocket assembly.
Preferably the drill rig comprises apparatus in accordance with the first aspect of the invention.
Preferably the drill rig comprises a hose restraint system in accordance with the second aspect of the invention.
Preferably the drill rig embodies a method in accordance with the third aspect of the invention.
It will be appreciated that features described in relation to one or more of the aspects may be applicable to one or more of the other aspects.
Brief Description of the Drawings
Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:
Figure 1 is a perspective view of an axially short section of an embodiment of a hose restraint apparatus in accordance with the present invention comprising an elongate flexible member in the form of a chain provided with spaced apart attachment portions, of which one is illustrated;
Figure 2 is a perspective view of the apparatus illustrated in Figure 1 in use with a hose attached thereto; Figure 3 is a side view of part of the apparatus illustrated in Figure 1 ;
Figure 4 is an end view on IV-IV of the apparatus illustrated in Figure 3;
Figure 5 is an end view of the apparatus as illustrated in Figure 2;
Figure 6 is a part sectional view of the apparatus as illustrated in Figure 5; Figure 7 is a schematic side view of a drill rig which includes the apparatus of Figures 1 to 6;
Figures 8 to 10 are schematic side views of the drill rig of Figure 7 in use; Figure 11 is a schematic partly cut away view of part of an alternative embodiment;
Figure 12 is a perspective view of the embodiment of Figure 11 ;
Figure 13 is a side view of a guide for the hose and elongate members, corresponding to the embodiment of Figures 11 and 12;
Figure 14 is a partial side view corresponding to Figure 13, showing the hose and elongate members in place;
Figure 15 is an perspective view of a hose confinement structure of Figure 14; and Figure 16 is a cross section of a sprocket assembly of Figures 11 to 14.
Detailed Description of Preferred Embodiments
With reference to Figures 1 to 6 an embodiment, generally designated 1 , of a hose restraint apparatus in accordance with the present invention comprises an elongate flexible member in the form of a chain 10 provided with spaced apart attachment portions, of which one 30 is illustrated.
The chain 10 comprises a number of links 12 pivotally connected together by pins 14, oriented perpendicular to the direction of elongation of the chain 10 and may be regarded as being somewhat similar in general construc- tion to a drive chain for a bicycle or motorbike. Thus the chain provides portions between the pins 14 which are adapted to engage a chain retainer in the form of a sprocket or the like. More specifically, each link may be regarded as being formed from two opposed side plates mutually connected at first end regions thereof by a first link cross member, and at second end regions thereof by a second link cross member. In at least some of the links the link cross members comprise pivot pins (such as pins 14) each pin also being utilised to pivotally connect the link to a respective neighbouring link, and each link providing a receiving space, defined by the side plates and cross members. The receiving space is adapted to receive a tooth of a sprocket or the like, which would, in use, be engaged by parts of the side plates and cross members adjacent the receiving space. A number of special links 17 are provided with attachment portions 30 in order that a hose to be restrained can be attached to the chain 10. Only one attachment portion 30 is shown in Figures 1 to 6, but in preferred embodiments attachment portions are provided at intervals along the length of the chain 10 so that a hose 60 can be attached to the chain at multiple points along the length of the hose 60 and of the chain. The attachment portions can be provided at any desired spacing, but a regular spacing of approximately every metre (or every three feet) along the length of the chain 10 is current considered appropriate for use with high pressure hoses. Of course, different, or even irregular spacings could be used if desired.
In the illustrated embodiment the (or each) attachment portion 30 comprises a first attachment part 32A extending outwardly and upwardly from a first side of the chain 10, and a second attachment part 32B extending outwardly and upwardly from a second side of the chain 10. In the illustrated embodiment 1 the first and second attachment parts 32A,32B are substantially mirror images of each other, and for ease of reference they will be describe together. In the illustrated embodiment 1 the first and second attachment parts 32A.32B are each symmetrical about a plane perpendicular to the direction of elongation of the chain, and they therefore comprise identical members, which facilitates manufacture. However, it should be appreciated that the attachment portions need not comprise two separate attachment parts, 30, and that even if the attachment portions do comprise two separate attachment parts, such parts need not be identical nor mirror images.
In the illustrated embodiment 1 each of the first and second attachment parts 32A.32B extends outwardly from a respective laterally outer part 16A.16B of a special link 17 of the chain 10 and is formed integrally with said respective outer part 16A.16B. The first and second attachment parts 32A.32B are thus mutually connected, via the respective laterally outer parts 16A, 16B, by two pins 14 which form part of the chain 10. Each of the first and second attachment parts 32A.32B is in the form of an arcuate curved plate which, as can best be seen in Figures 5 and 6, in use, engages and follows the curved outer surface of the hose 60. The first and second attachment parts 32A.32B together with a laterally central part 18 of the chain 10 which extends therebetween thus effectively provides an attachment portion 30 which can cradle an axially short length of the hose 60.
Each of the first and second attachment parts 32A.32B is provided with a respective slot 34A.34B at an upper and outer part thereof, and in use, as can be best seen in Figure 6, the slots 34A.34B allow connection to a retaining strap 40, which extends around the hose 60 and which is secured by a buckle 50.
The strap 40 and buckle 50 can be of any form and configuration suitable for attachment to the attachment portion 30 and for attaching the hose 60 to the chain 10.
In the illustrated embodiment, as can best be seen in Figure 6 the strap is of polymer webbing and comprises a loop 41 at a first end thereof which attaches to a first attachment bar 52 provided at a first end of the buckle 50. The strap extends from the loop 41 to the first attachment part 32A, passes through the slot 34A, doubles back and passes around most of the hose 60 including passing between the hose 60 and the buckle 50 and extends to the second attachment part 32B. The strap then passes through the slot 34B, doubles back and runs back to the buckle 50, where it passes a second attachment bar 54 provided at a second end of the buckle, before terminating at a second end 42 thereof. The buckle comprises a securing element 56 for preventing inadvertent release of the strap 40. The strap 40 can thus securely attach the hose 60 to the chain 10. A plurality of attachment portions 30, including straps 40 and buckles 50, spaced along the length of the chain 10 can thus attach the hose 60 to the chain along substantially the entire length of each. When restrained in this way, if the hose breaks the free length of hose which can snake or whip about because of the high pressure fluid being expelled is limited to the length of hose between the break and the nearest upstream attachment to the chain. It will be appreciated that it is relatively easy to reliably retain and restrain a chain within a desired range of positions, since a suitable chain can be retained by retainers such as sprockets, can withstand large tensile forces and is very durable (and thus unlikely to inadvertently break, which would result in the chain no longer being properly retained). By comparison, hoses are generally relatively difficult to retain and restrain within a desired range of positions, since they are relatively difficult to positively engage by retainers (without damaging or impairing the function of the hose), are more sensitive to large tensile forces and (at least in applications such as high pressure use in which cuttings are conveyed therethrough at high speed) are relatively prone to failure and breakage. The described embodiment thus provides a means of retaining a hose substantially as effectively as a chain can be retained. Of course it will be appreciated that many variations are possible. For example, in an alternative embodiment a strap and buckle is not used, but instead the attachment parts, in combination, extend around the hose and lock together. In this embodiment the attachment parts may each be substantially semicircular, and may be locked together using a mechanism such as an over- centre lever. The attachment parts may be made of metal, or may be formed from an alternative material, such as a plastic or rubber, which helps minimise the risk of damage or excessive wear being inflicted on the hose by contact with the attachment parts (as does use of a strap as described above). Some such embodiments could allow rapid attachment (and detachment) of the hose and flexible elongate member, facilitating quick replacement of broken or worn hoses. In further alternatives an attachment portion may comprise any suitable type of hose clip securely attached to the chain (or other elongate flexible member): for example a worm drive hose clip, such as those sold under the trade mark Jubilee clip, could be used. Further, it will be appreciated that although use of a chain is currently preferred, alternative forms of flexible elongate member could be used: for example a strong rope or chord, preferably steel wire rope, could be used (guides or retainers for steel rope are known per se, and used in cable car support mechanisms and/or or other fields); another example of an alternative flexible elongate member is a reinforced 'rubber' belt, for example of the general type used in mechanical power transmission of some machines, including some cars with continuously variable transmission. Some such belts include teeth on one side thereof, assisting engagement with retainers. In some embodiments the mechanical elements for attaching the hose to the flexible elongate member may be provided on the hose, rather than on the flexible elongate member.
Figure 7 is a schematic side view of an embodiment of a reverse circulation drill rig 70 in which the apparatus of Figures 1 to 6 is used. The drill rig comprises a vertical mast 72 (although it will be appreciated that a variation could comprise an inclined mast), and a drill head 74 which can travel up and down the mast in order to raise or lower a drill rod 76 through which high pressure gas carrying drill cuttings ascends. The hose 60 is attached to the drill head 74 for conveying the gas and drill cuttings to a desired location via a fixed bulkhead 78 near the bottom of the mast, to which the hose 60 is attached. (It should be appreciated that the hose may continue beyond the fixed bulkhead 78, and that it is therefore not necessarily an 'end' of the hose which is attached to the fixed bulkhead 78, but that because the part of the hose which is attached to the fixed bulkhead 78 is the end region of the part of the hose which is attached to the chain, and with which the present invention is particularly concerned, this may sometimes be referred to as an end or end region of the hose.) In order to avoid the hose 60 being deposited and coiling upon the ground when the drill head 74 is relatively low, and then being rapidly raised when the drill head ascends (which presents a significant safety hazard) the drill rig 70 is provided with a travelling reel 80, above the drill head 74, over which the hose 60 passes. The travelling reel 80 ascends and descends with the drill head 74, but at half the speed of the drill head 74, thereby taking up any slack that might otherwise occur in the hose 60 and so that the hose is maintained at substantially constant tension.
The hose 60 is attached to the chain 10 by attachment portions which in this embodiment includes the use of straps 40 (although as described above other types of attachment could be used), for example approximately every metre (or, eg, approximately every three feet) along the length of each.
A first end 11 of the chain 10 is attached to the drill head 74, and a second end 19 of the chain 10 is attached to the fixed bulkhead 78. The chain 10 passes over the travelling reel and is positively engaged by sprockets 82 provided on the travelling reel 80. The travelling reel 80, including the sprockets 82, is an example of a retainer for restricting the position of the elongate flexible member (and, consequently, the hose).
The drill rig 70, in use as the drill head ascends, is schematically illustrated in Figures 8 to 10. The hose 60 is maintained as a substantially upwards vertical run A between the drill head 74 and the travelling reel 80 and a substantially downwards vertical run B between the travelling reel 80 and the fixed bulkhead 78. Figures 8 to 10 illustrate that the vertical movement of the travelling reel 80 is half the vertical movement of the drill head 74, and that that this results in the sum of the hose run lengths, A plus B, being constant.
The illustrated embodiment thus provides a drill rig 70 in which the hose 60 is maintained in range of safe positions in use, and in which even if the hose 60 breaks somewhere between the drill head 74 and the bulkhead 78 it is restrained by its attachment to the chain, so that only a short length of hose 60 can move violently, and relative safety is therefore maintained.
An alternative embodiment is illustrated in Figures 11 to 16. In this embodiment a hose restraint apparatus in accordance with the present invention comprises first and second elongate flexible members, in the form of first-side and second-side chains 110, 110A (each of which is generally similar to the chain 10) adapted to receive a hose 160 therebetween and to be attached to the hose by spaced apart attachment portions 130. The chains 110, 110A are provided on substantially diametrically opposed sides of the hose 160, so that when the hose 160 and chains 110, 110A are guided by a guide or retainer, such as travelling reel 180 (which in the illustrated embodiment serves essentially the same purpose as travelling reel 80) the curvature applied to the hose 160 and chains 110, 110A is substantially the same. This can assist in avoiding the build up of forces between the hose 160 and chains 110, 110A which can occur if different degrees of curvature are applied to the hose and chain(s). For example, applying a radius of curvature to a length (say 1 metre) of hose between two attachment portions which is significantly greater than the radius of curvature of the length of chain between the two attachment portions, will either result in slippage between the hose and chain(s) or result in application of an undesirable tensile force to the hose.
As illustrated in Figures 12 and 14, each of the attachment portions 130 (which will be described in more detail below, with reference to Figure 15) are attached to both of the chains 110, 110A and support the hose 160 between the chains 110, 11 OA. Substantially the same degree of curvature is applied to the chains and (the axial centre of) the hose 160, when the hose and chains pass over the travelling reel 180.
The travelling reel 180 comprises a number of first-side sprockets 182 (five in the illustrated embodiment) which support and guide the first-side chain 110, and a number of second-side sprockets 182A (five in the illustrated embodiment) which support and guide the second-side chain 110A. Thus the chains 110A, 110B and the hose 160 are guided up and over the travelling reel 180, so that the travelling reel 180 can function (in an equivalent manner to travelling reel 80) to keep the chains and hose in a desirable and predictable range of positions as a drill head (not shown in this embodiment) moves along a mast of a drill rig.
In the illustrated embodiment the sprockets are provided as parts a number of sprocket assemblies 170, each including one first-side sprocket 182 and one second-side sprocket 182A. Each sprocket assembly is mounted to, and between, first-side and second-side plates 181 , 181 A of the travelling reel 180. (The first-side plate 181 is omitted in Figures 11 and 12 so that the structure between the first-side and second-side plates 181 , 181 A can be seen, but is shown in Figures 13 and 14, and indicated in Figure 16.)
As shown in Figures 13 and 16, each sprocket assembly 170 comprises rod 183 with threaded end portions, which extends between and through the first-side and second-side plates 181 , 181 A. A central spacer 184 is provided on the axially central region of the rod 183. Respective axial ends of the spacer 184 engage the first-side and second-side sprockets 182, 182A. Mounted on the rod 183, axially outwardly of the first-side and second-side sprockets 182, 182A, are respective, flanged, first-side and second-side bearing collars 185, 185A, which are bolted to the respective sprockets 182, 182A and which pass through respective apertures in the respective first-side and second-side plates 181 , 181 A. The axially outer ends of the bearing collars 185, 185A engage inner sides of respective first-side and second-side washers 186, 186A. Outer sides of the washers 186, 186A are engaged by respective first-side and second-side retaining nuts 187, 187A which are in threaded engagement with the threaded end portions of the rod 183 and which retain the sprocket assembly in position. It will be appreciated that alternative arrangements are possible: for example, in one alternative first and second side sprockets could be mounted on separate axles or rods, and might not be coaxial.
In this embodiment the central spacer 184 of each sprocket assembly 170 is adapted to be able to engage the outside of the hose 160, which assists guiding the hose, especially the regions of the hose 160 which are furthest from the attachment portions 130 (i.e. in the centre of a length of hose which extends between two attachment portions.) This assists in controlling the curvature of the hose 160 and keeping the curvature of the hose 160 the same as the curvature of the chains 110, 11 OA. The central spacers 184 are preferably made from (or coated with) material which avoids or minimises damage to the hose 160, such as a plastic or rubber material, and may be provided so that they can rotate on the rod 183, so as to act as rollers. In use, the apparatus is preferably dimensioned so that the central spacers 184 can engage the central region of a length of hose which extends between two attachment portions (as described above) but so that the metal attachment portions are supported as they pass over the sprocket regions so that they do not contact the central spacers 184, and damage to the central spacers 184 which could be caused by repeated contact with metal attachment portions is thus avoided. As best illustrated in Figure 13, the first-side and second-side plates 181 ,
181 A are spaced apart by a travelling reel bottom plate 189, which is connected (in this embodiment by bolts) to the first-side and second-side plates 181 , 181A by respective first-side and second-side brackets 190, 190A.
In this embodiment, the attachment portions 130 are in the form of metal confinement structures, as illustrated in Figure 13. Each confinement structure comprises a curved cradle portion 131 adapted to engage and pass around a lower (when the hose is horizontal) part of a short length of the hose 160. Each confinement structure further comprises a curved securing portion 134 adapted to engage and pass around a higher (when the hose is horizontal) part of a short length of the hose 160. The securing portion 134 can be secured to the cradle portion 131 to confine the hose 160. In the illustrated embodiment the securing portion 134 can be bolted to the cradle portion 131 at either side thereof via apertures 135, 135A provided in complementary portions 136, 136A, 137, 137A thereof, but it will be appreciated that various forms of attachment could be used, including hinged arrangements, buckles, over-centre levers or the like, as described above. In the illustrated embodiment the cradle portion 131 extends around considerably more of the circumference of the hose than does the securing portion 134.
In the illustrated embodiment the cradle portion 131 is provided with first and second first-side attachment elements 132, 133, and first and second second-side attachment elements 132A, 133A, for attachment to links of the chains 110, 110A. In this embodiment the attachment elements 132, 132A, 133, 133A are in the form of threaded rods which connect to the chains by extending through pivot pin apertures of certain chain links, and replace the normal pivot pins of those links. The attachment elements 132, 132A, 133, 133A can be secured relative to the chain links in any suitable desired manner, but in the illustrated embodiment are secured by nylon insert lock nuts.
In the illustrated embodiment the inside diameter of each confinement structure is about 10mm greater than the outside diameter of the hose 160 so that the hose is somewhat loosely retained rather than rigidly locked to the chains. This assists in avoiding undesirable compressive or tensile forces if there are slight differences in path (curvature) of the hose and chains. In the event of hose breakage the hose cannot snake through the confinement structures and become detached from the chains (and fall to the ground) because the spacing of the attachment portions (confinement structures) is arranged to be sufficiently small for the inherent structural rigidity of the hose to allow this to happen. (Of course, if the breakage were to occur at or very close to an attachment portion (confinement structure) the hose might become free of this one attachment portion (confinement structure) but would be unable to snake through either of the neighbouring confinement structures, and the free length of hose would thus be restricted to approximately the spacing between the confinement structures (typically about one meter) maintaining relative safety in the vicinity. In alternative embodiments at least part of each attachment portion may be attached substantially rigidly to the hose, but may be adapted to have some play relative to the chain(s) (or other flexible elongate member(s)). For example, an attachment portion may have a first part substantially rigidly attached to the hose and a second part substantially rigidly attached to the chain(s), but may be arranged so that there is some play, in the direction of elongation of the hose, between the first and second parts. This could be arranged, for example, by providing a suitable (for example sliding) linkage between the first and second parts.
In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.
Modifications and improvements may be incorporated without departing from the scope of the present invention.
The disclosures in the Australian patent application No. 2007903884, from which this application claims priority, are incorporated herein by reference.