AU2006203572A1 - Cable pulling apparatus for helicopters - Google Patents

Description

P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: "CABLE PULLING APPARATUS FOR HELICOPTERS" The following statement is a full description of this invention, including the best method of performing it known to me/us: SCABLE PULLING APPARATUS FOR HELICOPTERS This invention relate to cable pulling apparatus which in use is attached to a helicopter so as to enable the helicopter to advance a conductor towing line or cable along a power line while threading the towing line through a stringing block suspended from an insulator at each tower of the power line.

IND A conventional support apparatus for attachment of a conductor towing line to a helicopter comprises a cargo hook located at a primary or main lifting point on the underside of the helicopter located directly below a pivotal mount for each rotor of the helicopter. A wire rope was attached to the cargo hook and at a location about 100 feet down from the cargo hook in use had a counterweight of around 200-800kg was attached to the wire rope.

There was also attached to the counterweight a support hook for attachment of the towing line.

When using the abovementioned support apparatus for the towing line it was necessary for the helicopter to thread the towing line through a stringing block or pulley located at each cross arm of each of the power line towers. The stringing block was attached to an insulator attached to each end of an associated cross arm. The helicopter therefore towed or pulled the towing line from a cable drum or reel after disconnection therefrom. However it was found that this conventional method of threading the towing line through each stringing block or pulley was dangerous because of the use of the counterweight which greatly increased the load the helicopter had to carry and also it was necessary to avoid the counterweight impacting on an adjacent tower. The stringing operation could also only be used for a limited time in the air, e.g. 2 hours or less and was therefore capital intensive and uneconomic.

To overcome these problems use has been made of additional structure such as specialised threading apparatus shown in US Patent 4,278,237 or a stringing block having a split yoke mechanism as proposed in US Patents 3,868,069, 3,905,581 and 4,018,422 or a separable coupling as described in US Patent 4,006,884. However such additional structure not only complicated the threading operation but also added to the cost.

It is therefore an object of the invention to provide cable pulling apparatus which may alleviate the problems of the prior art discussed above.

The invention in one form provides a cable pulling apparatus for pulling of cable through one or more towers of a power line, for helicopters said cable pulling apparatus having: an elongate body; (ii) mounting means for mounting of the elongate body to a central lifting point of the helicopter in use; (iii) a cable support assembly location at an end of the elongate body remote from the mounting means; (iv) connection means associated with the elongate body for connection fo the elongate body to a secondary lifting point of the helicopter adjacent the central lifting point in use whereby; the elongate body extends laterally from a longitudinal axis of the helicopter with said cable support assembly located externally of the helicopter for pulling of cable laterally of the longitudinal axis of the helicopter and above or clear of a skid structure of the helicopter.

Preferably the elongate body comprises a main arm or rail which has the mounting means located at one end and the cable support assembly located at the other end and the connection means located intermediate each end and adjacent the mounting means.

The mounting means preferably includes a mounting bracket having an attachment aperture for attachment to an underside of the helicopter as well as a plurality of attachment apertures for attachment to corresponding apertures of the main support arm. However it will be appreciated that any other suitable releasable attachment means can be used to attach the mounting bracket to the main support arm such as a clamp. The mounting bracket may also have a bottom aperture for supporting a cargo hook for carrying additional loads if required. Preferably the bottom aperture is located in a support member which is pivotally attached to a clevis located at an adjacent end of the mounting bracket.

There also may be provided a connection bracket or adjustment bracket releasably connected to the main support arm and which is located at one of the secondary lifting points of the helicopter adjacent the central lifting point. This is a preferred form of connection means discussed above.

The adjustment bracket has a pivot structure located above its attachment location to the main support arm which enables pivotal movement about a longitudinal axis parallel with the main support arm. This is useful in installation of the main support arm to helicopters of different types.

The body also may include an auxiliary arm which is releasably attached to the main support arm and has one end attached to the adjustment bracket and another end attached to the cable support assembly.

The auxiliary arm is useful in that support struts may be pivotally attached thereto for attachment to additional lifting points of certain types of helicopters such as the B3 for example. Ends of these support struts may also be attached to one or more fixing locations or points on the helicopter fuselage or outer skin that do not correspond to the secondary lifting points.

Preferably one support strut may be attached to a secondary lifting point of the cable located rearwardly of the main lifting point and a fixing location located on a side of the helicopter.

Preferably the main support arm comprises a pair of opposed rails or channels which may be spaced from each other so that the mounting bracket and adjustment bracket may be located in a gap between each opposed rail.

This also facilitates attachment of the cable support assembly which also may have at least part thereof located in the gap.

The cable support assembly may have a support block releasably attached to the main support arm which has pivot structure attached thereto which enables a 3600 rotation about a longitudinal axis coinciding with the main support arm and limited pivotal movement up to 1200) about a transverse axis. This may be accomplished by a pivot block having a pair of opposed pivot brackets attached thereto which facilitate pivotal movement about the transverse axis. A support bracket for a cable may be attached to each opposed pivot bracket below the pivot block.

Reference may be made to a preferred embodiment of the invention as shown in the attached drawings wherein: FIG 1 is a schematic drawing showing the basic procedures involved in helicopter cable stringing using the cable pulling apparatus of the invention; FIG 2 is a view similar to FIG 1 showing the direction of pull of a helicopter used in the cable stringing process shown in FIG 1; FIGS 3, 4, 5 and 6 represent a front view, side view and a plan view showing a left hand mount and right hand mount respectively of the cable pulling apparatus of the invention when attached to a helicopter; FIGS 7, 8 and 9 show various alternative views of the cable pulling apparatus of the invention when attached to a helicopter; FIG 10 represents an exploded perspective view of a first embodiment of cable pulling apparatus in accordance with the invention; FIG 11 represents a similar view to FIG 10 illustrating a second embodiment of cable pulling apparatus in accordance with the invention; and FIG 12 represents a similar view to FIG 10 illustrating a third embodiment of cable pulling apparatus in accordance with the invention.

In FIGS 1 to 2 reference is made to a pair of towers 10 and 11 which are subject to a cable stringing operation involving cable 12 unwound from cable drum 13 having a braking device (not shown). A helicopter 14 shown in FIG 2 initially follows path 1 in attaching cable 12 to towers 10 and 11. Cable 12 is alternatively known as "draw wire" or "stockline". Along path 1 the helicopter 14 pulls cable 12 from drum 13 and passes cable 12 over a pulley (not shown) attached to insulator component or string 15 attached to cross arm 16 of tower 11 before passing of cable 12 over a pulley (not shown) attached to insulator component or string 15 attached to cross arm 16 of tower 10. At the end of path 1 the cable 12 is released from the helicopter 14 and then dropped on the ground. This also occurs to the other end of cable 12 adjacent cable drum 13 after disconnection from cable drum 13.

Subsequently the helicopter 14 returns to a position adjacent cable drum 13 and a new length of cable 12 is attached to helicopter 14 and the helicopter 14 travels along path 2. Subsequently the helicopter travels along paths 3, 4, 5, 6, 7 and 8 so that individual cable strands are supported from pulleys attached to each lower end of insulator 15 attached to each end of cross arms 16 of both towers 10 and 11.

Thereafter each strand of cable 12 is used to pull through the main power conductors (not shown) as is known in the art. It is noted that each of cross arms 16 are of lesser width as they approach the top of each tower and 11.

FIG 2 illustrates the cable pulling apparatus of the invention (not shown) attached to helicopter 14 wherein cable 12 is pulled from cable drum 13 and past tower 11 in a side direction or laterally of the longitudinal axis of helicopter 14. It will be noted that the cable 12 is pulled above the skid structure 9 of helicopter 14 and this is more clearly shown in FIGS 3 to 4.

FIGS 3, 4, 5 and 6 represent cable pulling apparatus 20 when attached to helicopter 14 and cable pulling apparatus 20 includes support struts 22 and 23 attached to helicopter 14. It will be appreciated that FIG 3 shows cable pulling apparatus 20 attached to the underside of helicopter 14 but on the left hand side and this is also shown in FIG 4.

This is also shown in the plan view shown in FIG 5 but it will be appreciated that cable pulling apparatus 20 may be attached to the underside of the helicopter 21 on the right hand side as illustrated by cable pulling apparatus 20 being in phantom in FIG 6. It is noted that one end 25 of cable pulling apparatus is located directly underthe main mounting assembly 26 for rotors 24 be it located on the right hand side or left hand side.

It will also be noted that cargo support assembly 34 may be located in a gap 7 between body 14B of helicopter 14 and skid structure 9 to facilitate the side pulling of cable 12 as shown in FIG 2.

There are also shown secondary lifting points 29A and 29B to which the adjacent end of support strut 23 is attached having regard to whether a left hand mount (FIG 5) or right hand mount (FIG 6) is used.

It will also be noted as described in FIG 2 above that the cable pulling apparatus is located above each longitudinal skid 9A of skid assembly 9 so that in use the cable 12 is pulled laterally of helicopter 14 clear of skid assembly 9.

In FIGS 7, 8 and 9 there is shown cable pulling apparatus 20 in greater detail including a main support arm 27 having a mounting bracket 28 for attachment of main support arm 27 to helicopter main lifting location 29 directly below rotor mounting assembly 26. There is also provided auxiliary arm 30 attached to main support arm 27 at 31 and 32. Auxiliary arm 30 is also attached to helicopter 24 at 32 by adjustment bracket 33. There is also provided cargo support assembly 34 at an outer end 35 of main support arm 27. Support block 37 interconnects auxiliary arm 30 and cargo hook assembly 34. Each of struts 22 and 23 may be attached to cargo hook assembly 34 by a clevis assembly 74.

A more detailed view of cable pulling apparatus 20 is shown in FIG and reference is made to main support arm 27 which is comprised of opposed channel members 27A and 27B interconnecting through opposed attachment apertures 40, 41 and 42. At end 25 of cable pulling apparatus there is provided a mounting bracket 28 having mounting apertures 46 coaligned with mating apertures 40 for insertion of various fasteners (not shown). Mounting bracket 28 also includes an aperture 47 in lug 48 for suspension from location 29. Mounting bracket 28 also has a bottom support member 49 connected to co-aligned apertures 50 of clevis 51 by aperture 52 for insertion of a fastener (not shown). Support member 49 also has a bottom aperture 53 which functions as an attachment point for equipment (not shown) suspended from bottom aperture 53 at lifting point 29. Thus support member 49 may pivot about an axis transverse to the longitudinal axis of main support arm 27.

Cable pulling apparatus 20 also includes adjustment bracket 33 having attachment apertures 56 which register with co-aligned apertures 41 of each channel member 27A and 27B. Reference is also made to fastener which extends through aperture 57 for attachment of bracket 33 to spacer 58. There is also provided the usual support fixture 59 which is normally part of the conventional helicopter support structure which is attached to the underbelly of the helicopter by a fastener (not shown) extending through attachment aperture 61. Support fixture 59 may pivot about an axis transverse to the longitudinal axis of main support arm 27. There is also provided clevis 62 having opposed lugs 63 and each having attachment aperture 64 through which a pivot bolt (not shown) extends and also through co-aligned aperture 60 of support fixture 59 wherein clevis 62 may pivot about an axis parallel to the axis of main support arm 27.

Adjustment bracket 33 also has opposed lugs 65 each having an attachment aperture 66 whereby a pivot pin (not shown) may extend through each aperture 66 as well as co-aligned aperture 67 of clevis 62 whereby adjustment bracket 33 may pivot in a direction transverse to the longitudinal axis of the main arm 27.

The purpose of adjustment bracket 33 and the two pivotal movements that have been described above means that prior to installation to a particular helicopter such pivotal movements can be taken into account in determining relative adjustments that have to be made so that main support arm 27 can be fitted to helicopters of different types.

Spacer member 58 is attached to pivotal support structure 70 for each of support struts 71 and 72 for B3 helicopters. On other helicopters support struts 71 and 72 and pivotal support structure 70 may be omitted. Each of struts 71 and 72 are connected to pivot joints 73 through clevis 74 and pivot pin 75 and each are attached to an associated support block 77. There is also provided spacers 78 whereby each of struts 71 and 72 may be pivoted about an axis about main support arm 30 for installation purposes. Each of support blocks 77 are provided with internal bores 79.

There is also provided auxiliary arm 30 having shoulders 80 and 81 as well as cargo hook assembly 34 comprising anchor block 37 having attachment apertures 85 which are co-aligned with attachment apertures 42 of main support arm 27 for attachment thereto by appropriate fasteners (not shown). Auxiliary arm 30 has an outer end 86 of reduced diameter which is located in support aperture 87 of anchor block 84. There is also provided support struts 22 and 23 attached to associated dclevises 74 whereby each of support struts 22 and 23 may pivot about an axis coinciding or parallel with auxiliary arm 30 for adjustment purposes when being attached or installed to a helicopter. There is also provided pivot pins 75 and each pivot pin extends through aperture 76 of adjacent bracket 82 aligned with co-aligned apertures 79 of each clevis 74.

Cable hook assembly 34 also includes outer end extension 90 of auxiliary arm 30 which has an inner end section 91 of reduced diameter for location in a suitable mating aperture (not shown) in anchor block 37. There is also included opposed pivot brackets 92, pivot block 93, lower pivot bracket 94 and stop plate 95 attached to pivot block 93 by fasteners 96 which extend through co-aligned apertures 97 and 98 in plate 95 and pivot block 93. Each pivot bracket 92 has an upper aperture 99 which engages a stub axle 100 on pivot block 93. Each pivot bracket 92 also has apertures 101 and 102 in registry with each other and also with co-aligned apertures 103 and 104 of pivot bracket 94. Extension 90 may be inserted through passage 105 of pivot block 94 and through the apertures of annular spacers 83 and as well as through apertures 107 and 108 of each pivot bracket 82.

The arrangement in cable hook assembly 34 is such that each of pivot brackets 82 and lower bracket 94 may pivot through 1200 and any further pivotal movement is prevented by stop plate 95. Also cable hook assembly 34 may pivot through 3600 around auxiliary arm This is better shown in FIG 11 which shows that inner end section 91 of auxiliary arm extension 90 engages in a threaded aperture 112 of outer end 86 of auxiliary arm 30 so as to attach outer extension 90 to auxiliary arm FIG 11 also illustrates the presence of shoulders 80 and 81 of auxiliary arm 30 providing a secure mounting for pivot blocks 77 of each support strut 71 and 72. This is facilitated by the use of spacers 78. Fastener 55 also engages in threaded socket 113 of spacer 58.

In FIG 12 there is shown in more detail cable hook assembly 34 and illustrating the pivotal movement of brackets 92 about pivot lugs 100. This is stopped by stop plate 95. There is also shown safety bolt 114. It will be appreciated that the support hook (not shown) for the cable 12 will be inserted in aperture 115 of pivot bracket 94.

FIG 13 basically shows the same arrangement as shown in FIG with support struts 71 and 72 and associated pivot structure 70 removed.

This means that auxiliary arm 30 is provided with projection 116 at its inner end adjacent support bracket 33 and having screw threaded aperture 117 for engagement with fastener In FIG 14 there is shown a further variation in the cable pulling apparatus of the invention with the cable hook assembly 34 removed for

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O clarity. In this arrangement extension arm 90 extends through bore 87 of support block 37 and inner end section 91 of reduced diameter is engaged by a collet or clamp (not shown). Thus in this variation auxiliary arm 30 has now been dispensed with as well as support struts 22 and 23 and associated pivot mounting apparatus comprising brackets 82, dclevises 74 and spacers 83. In this embodiment support brackets 28 and 33 function as described in Sthe FIG 10 embodiment and are attached to channels 27A and 27B as Spreviously described. However there are now provided additional channels 120 and 121 which extend rearwardly of support arm 27 having regard to the orientation of helicopter 14 and each channel 120 and 121 is attached at its rearward end to support bracket 33A which has the same structure as support bracket 33 and also carries out the same function as described in the FIG 10 embodiment. Thus there is provided fasteners (not shown) extending through a plurality of attachment apertures 122 and also through corresponding apertures 56A in bracket 33A. Each of channels 120 and 121 at their ends adjacent support arm 27 are attached to support block 37 and bracket 33 by appropriate attachment structure (not shown) which includes attachment brackets and associated fasteners.

Each of brackets 33 and 33A are suspended from conventional helicopter secondary lifting points 29C and 29D designated by the location of support brackets 59 which are located on either side of main lifting point 29 by the cable pulling apparatus 20 by used for a right had mount or a left hand mount. It also will be appreciated that bracket 59A will be attached to either of lifting points 29A or 29B by the cable pulling apparatus 20A by used for a V left hand mount or a right hand mount. These lifting points are shown in FIG 3. The load supported by primary lifting point 29 is 750kg. If both lifting points 29A or 29B are used the load that may be supported is 1100kg. If either lifting point 29C or 29D is used the load that may be supported is 1400kg.

Thus from the foregoing discussion the invention in another aspect refers to a method of advancing a cable inclusive of a conductor towing line IDas well as a conductor along a power line while threading the towing line C through one or more stringing blocks suspended from a plurality of towers of the power line which includes the steps of: attaching the cable to an outer end of an elongate mounting body which is attached to an underside of a helicopter at a central lifting point thereof and also at a secondary lifting point; and (ii) pulling the towing line through said stringing block(s) with the helicopter moving between adjacent towers with said towing line being located laterally of a longitudinal axis of the helicopter as well as being located above or clear of longitudinal skid members of the helicopter.

From the foregoing it will be appreciated that the cable pulling apparatus of the invention has a number of advantages over the prior art discussed above.

It does not require the use of a counterweight with subsequent disadvantages that are applicable thereto such as the cable in operation being pulled below the skid structure of the helicopter and thus possibly contacting or becoming entangled in the skid structure; (ii) Because of the lack of requirement of a counterweight the cable may be pulled in a direction that avoids extending below the skid structure; (iii) The cable pulling apparatus can be attached to the helicopter in a right hand or left hand arrangement which simplifies the cable threading procedure; and (iv) Both the pulling length of the cable or a longer wire may be 0 used.

Claims (16)

1. Cable pulling apparatus for pulling of cable through one or more towers of a power line, for helicopters said cable pulling apparatus having: an elongate body; (ii) mounting means for mounting of the elongate body to a central lifting point of the helicopter in use; (iii) a cable support assembly located at an end of the elongate body remote from the mounting means; (iv) connection means associated with the elongate body for connection of the elongate body to a secondary lifting point of the helicopter adjacent the central lifting point in use whereby; the elongate body extends laterally from a longitudinal axis of the helicopter with said cable support assembly located externally of the helicopter for pulling of cable laterally of the longitudinal axis of the helicopter and above or clear of a skid structure of the helicopter.

2. Cable pulling apparatus as claimed in claim 1 wherein the elongate body has a main support arm or rail with the mounting means located at one end and the cable support assembly located at the other end and the connection means located intermediate each end and inwardly of and closely adjacent to the mounting means.

3. Cable pulling apparatus as claimed in claim 2 wherein the main support arm has a pair of opposed rails or channels which are spaced from one another to define a gap for location of the mounting means and the cable support assembly.

4. Cable pulling apparatus as claimed in claim 1 wherein the mounting means includes a mounting bracket having an attachment aperture for attachment to an underside of the helicopter as well as a plurality of attachment locations for attachment to corresponding apertures of the elongate body.

5. Cable pulling apparatus as claimed in claim 4 wherein the mounting bracket has a bottom aperture for supporting a cargo hook for carrying additional loads if required.

6. Cable pulling apparatus as claimed in claim 5 wherein the bottom aperture is located in a support member which is pivotally attached to a clevis located at an adjacent end fo the mounting bracket.

7. Cable pulling apparatus as claimed in claim 1 wherein said connection means is a connection or adjustment bracket releasably connected to the elongate body.

8. Cable pulling apparatus as claimed in claim 7 wherein the adjustment bracket has a pivot structure located above its attachment to the elongate body which enables pivotal support about a longitudinal axis parallel to the elongate body.

9. Cable pulling apparatus as claimed in claim 2 wherein there is provided an auxiliary arm releasably attached to the main support arm having one end attached to the cable support assembly and another end attached to the connection means.

Cable pulling apparatus as claimed in claim 1 wherein the cable support assembly has a support block releasably attached to the elongate body which has pivot structure attached thereto which enables a 3600 rotation about a longitudinal axis coinciding with the elongate body and limited pivotal movement up to 1200 about a transverse axis.

11. Cable pulling apparatus as claimed in claim 10 wherein said pivot structure includes a pivot block having a pair of opposed pivot brackets attached thereto which facilitate pivotal movement about the transverse axis.

12. Cable pulling apparatus as claimed in claim 11 wherein a support bracket for a cable is attached to each opposed pivot bracket below the pivot block.

13. Cable pulling apparatus as claimed in claim 11 wherein there is provided one or more support struts pivotally attached to the auxiliary arm and located inwardly of the pivot block wherein said one or more support struts are attached to additional secondary lifting points of the helicopter located on a fuselage thereof.

14. Cable pulling apparatus as claimed in claim 13 wherein there are provided additional support struts extending laterally of the auxiliary arm and pivotally attached thereto and located adjacent the connection means.

A helicopter incorporating cable pulling apparatus as claimed in claim 1 wherein the elongate body is attached to a central lifting point of the helicopter by said mounting means and said connection means is attached to a secondary lifting point of the helicopter adjacent the central lifting point wherein the elongate body extends laterally from a longitudinal axis of the helicopter with the cable support assembly located externally of the helicopter for pulling of cable in use laterally fo the longitudinal axis and above or clear of a skid structure of the helicopter.

16. A method of advancing a cable inclusive of a conductor towing line as well as a conductor along a power line while threading the towing line through one or more stringing blocks suspended from a plurality of towers of the power line which includes the steps of: attaching the cable to an outer end of an elongate mounting body which is attached to an underside of a helicopter at a central lifting point thereof and also at a secondary lifting point; and (ii) pulling the towing line through said stringing block(s) with the 19 helicopter moving between adjacent towers with said towing line being located laterally of a longitudinal axis of the helicopter as well as being located above or clear of any longitudinal skid members of the helicopter.