APPARATUS AND METHODS FOR LINE STRINGING WITH LOAD PICKUP COUPLING DEVICE

Abstract: The problem of stringing power transmission lines via a line-holding structure that has an upper cross support and no side access, such as the center strand under a cross support on a tower, is solved by the methods and stringing apparatus disclosed. The stringing apparatus (40) is carried in a depending manner from the aircraft (10) by a hoist line (54) and enables the insertion of a sock line (30) through the line-holding structure (29), followed by the pulling of the line therethrough. The stringing apparatus is in the form of a needle-type structure, inclusive of a support member (42) carrying front and rear coupling devices (46 and 48) and front and rear tower catches (50 and 52). After the sock line has been strung, one end is secured to a power line which is then threaded through the line-holding structure to complete the stringing of a center strand of power line. A coupling device (515) disclosed includes a pivot member (517) pivotally mounted on the load having a disposition and configuration that is readily engaged by a hoist line (542) with an end or weight member (543) from above and guided into a retainer portion (522) so that as the hoist line is raised a connection is formed between the hoist line and the load. Upon deployment and relief of the weight of the load from the hoist line, the pivot member automatically returns to the starting position and the hoist line and end member are slid therefrom.

Description: APPARATUS AND METHODS FOR LINE STRINGING WITH LOAD PICKUP COUPLING DEVICE Technical Field This invention relates to novel and improved methods and apparatus for line stringing that is par¬ ticularly suited for stringing line through towers with line-holding structure that has no side access such as for the stringing of a center line and includes a novel load coupling device and method. Background Art The advantages of stringing electric power lines by helicopter or the like are well known. In the past for airborne stringing of power lines the practice has been to provide blocks on the support towers through which the personnel in the helicopter can. readily string the power line. The use of helicopters and suitable string¬ ing apparatus and methods as presently known have been confined to towers having a side access as illustrated in U. S. Patent No. 4,129,287. There are, however, a number of towers presently in use and designed for future use wherein the center power line is entirely closed on all sides at the point of attachment, and this, of course, poses particular problems for string- ing by helicopter or the like. The present prior art approach is to use conventional ground equipment. In the past a common practice in airlifting loads has been to use a grappling hook or some other type of hook on the end of a hoist line to hook into the load or a cable attached to the load. In most cases ground personnel is used to make certain there is a reliable connection between the hoist line and the load. In many aerial load pickup situations it is also highly desirable to be able to readily release the load from the hoist line without ground personnel. An example of the requirements of this type of coupling is the stringing apparatus disclosed herein. Disclosure of Invention In accordance with the present invention there are disclosed apparatus and methods using an aircraft for passing a sock line through a line-holding struc¬ ture for the center power line of a series of towers. A needle-type apparatus uses a pair of tower catches and a pair of line fasteners on a common support mem¬ ber to thread the line. The methods include suspend¬ ing the line, which is typically a sock line, from an aircraft and threading the sock line through a line- holding, structure, all of which are carried out by the operator in the aircraft, followed by attaching the . sock line to the power line and a pulling of the power line through the line holding structure. There is further disclosed a load pickup coupling device and method for use in retrieving a load by a helicopter and like aircraft which includes a pivot member shown in the form of a hook-like structure or a bail-like structure defining a central receiving area disposed in a substantially horizontal plane. The hook-like pivot member is pivotally mounted to pivot relative to the load about a horizontal axis from a generally prone position to an upright suspended position. The configuration and disposition of the pivot member is .such that a hoist line with an enlarged end member or weight below the pivot member may pass into the receiving area and into a retainer portion defining an internal retainer area that is smaller than the end ~' '' 1 ^ ' member and arranged so that as the hoist line and end member are raised by the aircraft the end member en¬ gages the retainer portion, the pivot member is piv¬ oted to an upright position, and a load-bearing con- nection is established between the hoist line and load. When the weight of the load is supported by something other than the hoist line, the pivot member pivots back to the horizontal position and the hoist line and end member slide from the retainer portion and out through the receiving area of the pivot member. Brief Description of Drawings The details of this invention will be de¬ scribed in connection with the accompanying drawings, in which: Fig. 1 is a perspective view of a helicopter supporting a needle-type stringing apparatus for string¬ ing a line to towers; Fig. 2 is a top plan view of the needle-type stringing apparatus shown in Fig. 1; Fig. 3 is a sectional view taken along lines 3-3 of Fig. 2; Fig. 4 is a side elevational view of an al¬ ternative embodiment of a needle-type apparatus; Fig. 5 is a top plan view of another form of line stringing apparatus; Fig. 6 is a side elevation view of the device shown in Figure 5; Fig. 7 is an enlarged sectional view taken along lines 7-7 of Figure 5; Fig. 8 is a side elevation view of another arrangement for the front coupling device and front catch; Fig. 9 is a sectional view taken along lines 9-9 of Figure 5 with alternate positions for the rear catch shown in dashed lines; Fig. 10 is a top plan view of a coupling device embodying features of the present invention; Fig. 11 is a side elevation view of the 5 coupling device shown in Figure 1; Fig. 12 is. an enlarged end elevation view of a portion of the coupling device shown in Figure 10 with the pivot member upright; Fig. 13 is an enlarged side elevational view 0 of the pivot assembly of Figure 12; Fig. 14 is a sectional view taken along lines 14-14 of Figure 12; Fig. 15 is a pictorial view of the deployment of a helicopter with a hoist line having an end member 5 on the lower end for engaging the coupling device shown in Figure 10; Fig. 16 is a pictorial view of the load being carried by the helicopter via the coupling device; Fig. 17 is a pictorial view of the load in a 0 ground-supported position with the pivot member moving with the end member extending back toward a horizontal position prior to release of the end member and hoist line from the device; Fig. 18 is a top plan view of another form of 5 aerial coupling device embodying features of the present invention; and Fig. 19 is a side elevation view of the device shown in Figure 18. Detailed Description Q Referring now to Fig. 1, a helicopter 10 is shown stringing a line 30 to a series of towers 14 dis¬ posed at spaced intervals. The towers 14 are conven¬ tional high-tension towers having a pair of laterally spaced vertical poles 16 and 18 that are anchored to ________ ~V,"IrO the ground and a cross support 20 attached at the top of the vertical poles 16 and 18 for supporting the strands of the high tension power line. The towers 14 are illustrated as having generally cylindrically shaped poles 15 and 18 and a generally rectangularly shaped cross support 20. It is understood that the ap¬ paratus and method of the invention may be used with a variety of types of towers and only one pole instead of two may be used per tower. As illustrated, the cross supports 20 of the towers 14 are adapted to support three strands of high tension electric power line, two outside strands 22 and 24 are shown and a procedure for stringing the center or " middle " strand Is described herein. The-outside strands of power line 22 and 24 are attached to the cross support 20 utilizing a conventional electric in¬ sulator 28, as will be the middle strand of power line upon completion of the installation. In practice, a stringing block 29 or like line-holding structure is mounted on the lower end of each insulator 28 to facil¬ itate the stringing operation. Blocks of this type are disclosed in U.S. Patents Nos. 4,129,287 and 3,195,862. For installing the center s.trand of power line, a preliminary stringing line commonly known as and here- in referred to as sock line 30 is unrolled continuously from a large spool supported on the ground at one end of the series of towers being strung, using the string¬ ing apparatus of the present invention. The sock line 30 is strung the entire length of the series of towers and has an end coupling that is connected to an end of the center strand of power line or conductor. A winch-type puller on the ground is used to pull the sock line 30 back to its original position and thereby threads the power line connected thereto through the line-holding structure that had previously been occupied by the sock line 30. During the threading of the power line through the line holding structure it is maintained in tension by conventional tensioner ap¬ paratus on the ground. While it is tinderstood that the methods and apparatus of the present invention are suitable for di¬ rectly stringing at least relatively short lengths of power line, the weight of a typical length of power line would be too great for lifting by the aircraft. In ad- dition, power line or electrical conductor is vulnerable to nicks and scratches. The sock line 30 is consider¬ ably lighter and more durable and typically is in the nature of a stranded cable made of strong, lightweight materials such as steel, nylon, polyethylene and the like. A needle-type stringing apparatus 40 shown in Figs. 1 and 2, generally stated, comprises a support member 42 in the form of an elongated cylindrically shaped rod, a generally U-shaped sock line fastener 44 attached at the rear end of support member 42, a front hoist line fastener 46 attached at the front end por¬ tion of the support member 42, and a rear hoist line fastener 48 attached to the support member a selected distance rearwardly of fastener 46 and between fastener 44 and fastener 46 for attaching the stringing apparatus 40 to a hoist line 54 depending from the helicopter 10 or like aircraft. A front hook-shaped tower catch 50 is mounted on support member 42 behind fastener 46 and a rear hook-shaped tower catch 52 is mounted on member 42 rearwardly of fastener 48. Catch 50 is between fas¬ teners 46 and 48. The function of catches 50 and 52 is to catch hold of and temporarily secure the stringing apparatus to the support tower as the tension in the line 30 pulls one of the catches 50 or 52 against the support tower. c.._rι Counterweights 56 and 58 are shown mounted on support member 42 directly opposite catches 50 and 52, respectively, to counterbalance the associated catches for ensuring that the catches are disposed in a hori- zontal plane and not turned at an angle so as to readily catch the tower -pole 16. The line fasteners 46 and 48, respectively, are thus located axially in front of catches 5Q and 52, respectively. Each line fastener 46 and 48 includes a generally U-shaped eyelet or lug portion 60 on a ring- shaped base portion 61 that in turn is rotatably mounted on support member 42. Stops 62 are provided for each fastener 46 and 48 and are attached to the support mem¬ ber 42 on either side of the body to limit the axial movement of the fasteners with respect to the support member and also limit the rotational movement of the fasteners to 90° with respect to the support member so that the lug portion will rotate between a horizontal position ready for being hooked and a vertical posi- tion when it is hooked and carried by the hoist line. The catches 50 and 52 are located opposite the lug portions 60 when the lug portions are in the horizontal position and swing to the vertical position at right angles to the catches so that the catches will catch hold of the sides of vertical poles. The stops 62 are attached to the support member at a point approximately even with the attachment point of the catches 50 and 52 to the support member. As shown in Fig. 1, a grappling hook 70 or similar device may be attached to the hoist line 54 for releasably attaching the hoist line 54 to the fas- teners 46 and 48 of the needle-type stringing apparatus 40. The catches 50 and 52 of the stringing appa- ratus 40 are generally hook-shaped and are constructed to temporarily secure the apparatus 40 to a generally cylindrical vertical pole 16 of the tower 14 and sup¬ port the sock line 30 while the sock line is threaded through the tower 14. The stringing apparatus 40 is adapted to string the sock line through a series of tower supports 14 by a method that generally includes the steps of pulling the stringing apparatus 40 with the sock line 30 attached thereto between the towers 14 with the hoist line 54 of the helicopter 10 supporting the stringing apparatus 40 on a tower 14 while the string¬ ing apparatus 40 is released from the hoist line 54, flying the helicopter 10 and hoist line 54 around the tower 14, reattaching the hoist line 54 to the string- ing apparatus 40 on the opposite side of the tower 14, and then pulling the stringing apparatus 40 and sock line 30 through the tower 14. Finally, after the sock line has been strung through all of the towers, one end is secured to the power line and the power line is threaded through the support structure to replace the sock line. More specifically, the method is preferably carried out by first fastening the sock line 30 to sock line fastener 44. The grappling hook 70 of the heli- copter haul line 54 is attached to the rear hoist line fastener 48 for pulling the stringing apparatus through the air. The airborne stringing apparatus is then pulled through the tower 14 and the leading tower catch 50 of the apparatus is hooked around a support pole 16 on the tower 14. The tension on the sock line 30 helps to maintain the stringing apparatus 40 in position on the pole 16. The hoist line 54 is then released from the rear fastener 48 and the helicopter flies the hoist line 54 around to the opposite side of the tower 14. The G.-'H hoist line 54 is then reattached to the front hoist line fastener 46 and the helicopter 10 pulls the stringing apparatus 40 through the tower 14 and hooks catch 52 to the tower pole 16. The hoist line 54 is then released from front hoist line fastener 46 and is reattached to rear hoist line fastener 48. The stringing apparatus 40 can then be pulled through the tower 14 by the aircraft and the operation can be repeated at the next tower. Referring now to Fig. 3, another embodiment of the needle-type stringing apparatus is shown and is generally designated 80. Apparatus 80 is formed with generally square-shaped front and rear tower catches 82 and 84. The catches 82 and 84 have front and rear hoist line fasteners that are located with the lug portion on the same side of the support member when the lug portion is in the horizontal position so that the catches will catch hold of the cross support 20 of the tower. Counterweights 86 and 88 are shown mounted on support member 42 directly opposite catches 82 and 84, respec- tively, to counterbalance the associated catches. The lug portions swing 90° from a horizontal to a vertical position when supported by the hoist line. This ar¬ rangement functions in the same manner as previously described except that during operation of the apparatus the square-shaped tower catches 82 and 84 are designed to support the apparatus on the generally rectangularly shaped cross support member 20 of the tower 14 rather than on the vertical tower poles 16 and 18. The line stringing apparatus 571 shown in Fig- ures 5-9 includes a support member 572 in the form of an elongated cylindrically shaped rod, a front hoist line fastener or coupling device 515a attached at the front end of the support member 572, and a rear hoist line fastener or coupling device 515b attached to the support member 572 between the ends thereof a selected distance behind coupling device 515a. The stringing apparatus further has a front tower catch 575 adjacent to and rearwardly of the front coupling device 515a and a rear tower catch 576 for- wardly of the rear. coupling device 515b. A line fas¬ tener 578 is connected to the rear end of the support member for fastening the sock or pull line 579 to the support member 571. The line fastener 578 has a mount¬ ing bracket clamped to the support member 571 and a clevis held by the fastening bolts. The sock line 579 is secured to the clevis. Coupling devices 515a and 515b are of a con¬ struction similar to device 515 hereinafter described and differ from one another only in the relative propor- tions of 'the shank portion and retainer portions. The front coupling device is shorter for added strength. As shown in Figure 7, each of these coupling devices 515a and 515b has a pipe-clamp-type circular mounting bracket 581 that fits around the support member 572 and has flange plates 582 and 583 through which one or more bolt fasteners 584 pass to releasably clamp the coupling device to the support member at the desired position. This allows the member to be located at any position along the support member and be adjustably moved as required. The pivot member carries a stop 586 to hold it in the horizontal position and a stop 587 to hold it in the upright position or at any desired angular position in between. For some applications the stops enable the pivot member to swing a full 180°, as is shown in Figure 1. The front tower catch 575 includes a releas- able and slidable mounting bracket portion 575a similar to bracket 581 above described to permit this catch to be slidable along the support member 572 and located at a selected position by tightening the bolt fasteners that extend through the flanges of the bracket, to¬ gether with a rearwardly and downwardly inclined hook¬ ing arm portion 575b adapted to hook over the top of the cross support on the tower designated by dashed lines at 577. The front tower catch 575 may also be located forwardly of the front coupling device 515a, as shown in Figure 8. The rear tower catch 576 includes a releasable and slidable mounting bracket portion similar to bracket 581 above described and has an outwardly and rearwardly extending arm portion provided with flat surfaces that are particularly suited for engaging wood. The rear tower catch 576 shown in Figure ' s 5 and 9 ex- tends laterally out from one side of the support mem¬ ber 572 opposite the normal position for the pivot mem¬ ber 517 and is positioned for a side hookup with .the upright side pole of a support tower indicated at 580. The rear tower catch 576 may be disposed at the opposite side at 576b, on top as indicated at 576a, or on the bottom as indicated at 575c with respect to the support member, as shown in dashed lines in Figure 9, depending on the type of tower engagement or hookup required. The upstanding or top disposition indicated at 576a with the catch located forwardly and adjacent catch 575, as shown in dashed lines in Figure 6, is particularly suited for having the catch engage the underside or bottom of a cross support 577 on a tower. A preferred procedure for stringing a sock line through the line-holding structure of a tower that has no side access, such as the center line, using line stringing apparatus 571 above described, is as follows: The end member or ball 543 on the end of the hoist line is placed in the front coupling device 515a and the line stringing apparatus 571 is moved in by the aircraft and set on the top of the cross support 577 of the tower or other support structure with arm por.- tion 575b hooked on support 577 and the sock line 579 providing a tension to hold apparatus 571 in place. 5 The line and end member are removed from the front coupling device 515a and connected to the rear coupling device 515b, which is the loaded position ready for threading. The line stringing apparatus 571 is then Q lifted off the tower, backed up and threaded through the tower by manipulating the aircraft. The top front catch 576a may hook the bottom of the tower or the side mount front catch may hook the side of the tower, ac¬ cording to the type of tower, and the stringing appa- ratus is again supported by the tower. The end member 543 is decoupled from the rear coupling device 515b and hooked into the front coupling device 515a and the line 579 is threaded through the tower and moved down to the next tower by the aircraft, where the front catch is 0 again set on the top cross support 577 and the above procedure is repeated. Referring now to Figures 10-19 of the draw¬ ings, a load pickup coupling device 515 shown is mounted on load 516 represented in a general form as a rectan- gular block. This coupling device 515, generally stated, has a single hook-shaped pivot member 517 pivotally connected at one end to the top of the load by a pivot assembly 518 to pivot about a substantially horizontal axis between selected positions described hereinafter. The pivot member 517 shown is comprised of a shank portion 521 and a U-shaped retainer portion 522 with an outwardly flared end portion 523 opposite as¬ sembly 518 which define an interior receiving area with a receiving opening 524 for the line along one side op- posite the shank portion and between the end of the end portion 23 and the load. This configuration for the pivot member and the fact that it is disposed substan¬ tially on its side in a prone position as shown in Figure 10 provides a load-supported, line-engaging target area for the hoist line. In practice the hoist line and end member are moved by the aircraft and engage the pivot member so that its external edge assists in guiding the hoist line toward the opening in the hook between the flared end portion and the load. The outwardly flared end portion facilitates guiding of the hoist line into the opening in the hook and against the inner edge of the shank portion, which then serves as a _line-engaging target area for the hoist line and guides the hoist line into the retainer portion 522. The retainer por¬ tion 522 is larger than the cross section of the hoist line and smaller than the cross section of the end mem¬ ber carried by the hoist line. Once carried by the hoist line, the pivot member 517 and its pivotal con- nection at the assembly 518 become load-bearing or load- suppor ing- members between the-hoist—line—and-load. The pivot member 517 shown is made of a solid rod 525 of circular cross section with a reinforcing plate 526 that extends along the shank portion and one side of the retainer portion for added strength. The pivot assembly 518 for the pivot member 517 includes a transverse pivot rod 531 affixed to the end of the shank portion opposite the retainer portion adapted to rotate about a horizontal axis, together with a mounting plate 532 which carries a pair of sleeve bearings 533 and 534 affixed thereto. The pivot rod 531 is telescopically received in and retained at opposite ends by the sleeve bearings 533 and 534. A horizontal stop 535 is carried by the shank portion and engages the mounting plate 532 to hold the pivot member 517 in the horizontal position on one side, and a horizontal stop 536 is mounted on the opposite side of the pivot member to hold the pivot in a horizontal position when swung to an opposite position as shown in dashed lines. It is understood that the stops 535 and 536 may be shaped to position the pivot member at an upward incline to the horizontal if desired, but in most cases this angle would be small and would not ex¬ ceed 45°. Screw fasteners 537 are shown holding the mounting plate to the load. While a mounting plate is shown, it is understood that other fastening techniques may be used to fasten the pivot assembly 518 to the load and other forms of pivots may be used to pivotally mount the pivot member 517 to a load. Referring now to Figures 15-17, the load 516 with a coupling device 515 mounted thereon, as above de¬ scribed, is shown on a supporting surface 538. A heli¬ copter-type aircraft 541 has a hoist line 542 suspended thereon with an end member 543 in the form of a ball forming a weight on the lower end. Shapes other than spherical could be used. The helicopter positions the end member 543 below the pivot member and the line 542 is moved toward the shank portion 521 through the receiving opening 524, usually against the inner edge of the shank portion wherein it is guided thereby into the retainer portion 522. The end member 543 is then raised against the re¬ tainer portion and at the same time the pivot member swings up about the pivot and forms a connection between the load and the helicopter so that the helicopter may elevate the load, as shown in Figure 16. To release the load from the hoist line, upon the placement of the load on a support surface the pivot member will tend to swing in the direction of the end member 543 and lie back down to the horizontal position, G whereupon the end member 543 may be slid from the re¬ tainer portion and out the receiving opening of the hook in reversal of motion to that of its application. In Figures 18 and 19 there is -shown another form of coupling device 555 ' including a pivot member 557 and a pivot assembly 559 connected at each end to the load 516. Pivot member 557 is in the nature of a modi¬ fied U-shaped bail comprised of a pair of oppositely disposed, spaced, arcuate shank portions 560 and 561, each pivotally connected at one end to the load and connected at the opposite end to a U-shaped retainer portion 562. The shank portions 560 and 561 form a receiving area through which the end member will insert and the inside edges guide the hoist line into the re- tainer portion. Again the retainer portion 562 is smaller in size than the end member to form the connection. The pivot assembly 559 at each end is shown to include a mounting plate 558 held to the load as by bolt fasteners with a pivot stud 563 extending through a hole in the end of the shank portion having a retainer head 564. Suitable stops 565 are provided on each shank portion to dispose the pivot member at an angle to the horizontal, preferably of about 30° but usually not more than 45°. The angular position. llows the hoist line and end member to be moved into the receiving area toward the retainer portion 562 from the side. This configuration for member 557 provides a generally wider target area for the hoist line and end member. The operation of the coupling device 555 is similar to that of device 515 above described and the interior receiving area formed by the pivot member must be large enough for the end member on the hoist line to be moved into the receiving area from the side toward the retainer portion 562. The width of the retainer portion 562 allows the line to slide thereinto and engage the end member when it .is pulled up against same. c.: # '' -' -

Claims: WHAT IS CLAIMED IS: 1. Stringing apparatus for a line comprising: support means; fastening means for attaching a hoist line carried by an aircraft to said support means for suspending said support means from an aircraft; and threading means operatively associated with said support means to pass an end of a line through a line-holding structure supported by an upper cross support on a tower with no side access while suspended from the aircraft. 2. Stringing apparatus for a line comprising: support means in the form of an elongated rod; fastening means for attaching a hoist line carried by an aircraft to said support means; first and second hoist line fasteners spaced from one another on said support means for re- leasably connecting said support means to the lower end of said hoist line; first and second tower catches each gen¬ erally in the form of a hook on said support means for releasably engaging portions of a tower to catch hold of and secure said support means to the tower after said hoist line is released from said support means, said first hoist line fastener being in front of said first tower catch and said second hoist line fastener being in front of said second tower catch whereby the hoist line is first secured to said second hoist line fastener and said support means is first secured to the tower by said first catch and advanced relative to the tower by releasing said second catch, flying to a position for engaging said leading hoist line fastener to move said second tower catch into engagement with said tower and reattach said hoist line to said second hoist line fastener; and threading means operatively associated with said support means to pass an end of a line through a line-holding structure supported by an upper cross support on a tower with no side access while suspended from the aircraft. 3. Stringing apparatus as set forth in claim 2 wherein each of said hoist line fasteners has a lug portion on a ring-shaped base portion rotatably mounted on said support means to move between a horizontal position and a vertical position and further including stops on said support means to limit the rotational movement of said base portion between said positions. 4. Stringing apparatus as set forth in claim 2 wherein said first and second tower catches are oppo- site said lug portion when said lug portion is in the horizontal position to catch hold of a vertical tower and said catches are at right angles to said lug por¬ tion when said lug portion is in the vertical position. 5, Stringing apparatus as set forth in claim 2 wherein said catches are on the same side of said lug portion when the lug portion is in the vertical posi¬ tion to catch hold of the upper cross support on the tower. 6, Stringing apparatus as set forth in claim 2 wherein said stringing apparatus is for passing a sock line through a line-holding structure on a tower. Stringing apparatus for a line compris- support means; fastening means including a coupling device for attaching a hoist line with an end member carried by an aircraft to said support means for sus¬ pending said support means as a load from an aircraft, said coupling device including pivot means pivotally connected to the load and disposed in a first position and arranged to pivot about a substantially horizontal axis between the first position and a second position, said pivot means defining an internal receiving area for said hoist line, said pivot means having an elongated shank portion pivotally connected at one end to the load and a retainer portion extending beyond said shank poirtion opposite said pivotal connection for receiving the hoist line whereby, after the hoist line is passed into said receiving area with the end member below said pivot means and said hoist line is moved into said retainer portion, the upward movement of said end member against the retainer portion by up¬ ward forces applied to said hoist line raises the pivot means to the second position, forming a connection at said hoist line and pivot member; and threading means operatively associated with said support means to pass an end of a line through a line-holding structure supported by an upper cross support on a tower with no side access while suspended from the aircraft. 8. Stringing apparatus as set forth in claim 7 wherein said support means is in the form of an elongated rod-like support member having a front coupling device and a rear coupling device mounted on said support member adapted to be coupled to a hoist line, the rear of the support member being connected to a stringing line, a front tower catch at the front of said support member, and a rear tower catch on said support member between said first and second coupling • devices, said coupling devices and tower catches being releasably clamped to said support member to be rotated to any annular position and located at a selected position along said support member. 9. Stringing apparatus as set forth in claim 7 wherein said front tower catch is positioned for¬ wardly of the front coupling device at the forward end of the support member and includes a rearwardly and downwardly inclined arm adapted to rest on and en- gage an upper cross support of a tower and be held in place by the tension on said stringing line. 10. Stringing apparatus as set forth in claim 7 wherein said pivot means is in the form of a single hook-like pivot member and has an outwardly flared end portion opposite its pivotal connection to the load to facilitate the movement of the hoist line into the retainer portion. 11. Stringing apparatus as set forth in claim 7 wherein said end member is in the form of a ball forming a weight at the lower end of the hoist line. 12. Stringing apparatus as set forth in claim 7 whereby, upon the subsequent supporting of the load by other than the hoist line, the pivot member auto¬ matically returns to the first position and the hoist line and end member are removed from a connection to the pivot member by passage back through said receiving area. 13. A method of stringing a line comprising the steps of: O. -PI suspending a stringing apparatus from an aircraft; and threading one end of a line through a line-holding structure supported by an upper cross support on a tower with no side access while suspended from the aircraft. 14. A method for the airborne stringing of a line via a line-holding structure on a tower having an upper cross support from which is supported said line-holding structure having end access but no side access, comprising the steps of: suspending a sock line from a hoist line attached to an aircraft; advancing the sock line through one end of the line-holding structure while the aircraft is hovering thereover; holding the sock line captive on the tower; releasing the sock line from the hoist line; flying the vehicle to the opposite end of the line-holding structure; reattaching the hoist line to the sock line; pulling the sock line through said line- holding structure; and pulling a power line via the line-holding structure to replace said sock line to thread said line- " holding structure. 15, A method of stringing a line through a tower using an aircraft comprising the steps of: suspending an end ' of a hoist line rom the aircraft; coupling the hoist line to a line string¬ ing structure including an elongated support member, a front tower catch at the front of the support member . and a stringing line attached at the rear of the sup- port member; positioning the line stringing structure - on a tower using the front tower catch and tension on the stringing line to hold the line stringing struc¬ ture on the tower; coupling the hoist line to the support member at an intermediate position rearwardly of the front tower catch and raising the line stringing structure from the tower; threading the line stringing structure through the tower and engaging a rear tower catch on the support member with the tower; decoupling ' the hoist line from the inter¬ mediate position on the support member and coupling the hoist line to the front of the support member; and pulling the support member and attached stringing line through the tower. 16. A load pickup coupling device for en¬ abling a hoist line having an end member to be con¬ nected to a load comprising: pivot means pivotally connected to the load and disposed in a first position and arranged to pivot about a substantially horizontal axis between the first position and a second position, said pivot means defining an internal receiving area for said hoist line, said pivot means having an elongated shank por¬ tion pivotally connected at one end to the load and a retainer portion extending beyond said shank portion opposite said pivotal connection for receiving the hoist line whereby, after the hoist line is passed into O.:?I said receiving area with the end member below said pivot means and said hoist line is moved into said re¬ tainer portion, the upward movement of said end member against the retainer portion by upward forces applied to said hoist line raises the pivot means to the sec¬ ond position, forming a connection at said hoist line and pivot member. 17. A method of coupling a load to a flying aircraft comprising the steps of: flying an aircraft with a suspended hoist line and a lower end member to be selected location; moving said end member below a pivot member disposed in a first, position and pivotally connected at one end to the load to pivot about a horizontal axis and into a retainer portion smaller in size than the end member and larger in size than the hoist line; and raising the hoist line to move the end member against the retainer portion to form a connec¬ tion between the pivot member and hoist line.

Inventors: CHAPMAN C
Applicants: CHAPMAN C
Application year: 1980
Main classification: B66D1
IPC codes: H02G1