US3479014A

US3479014A - Versatile sheave block

Info

Publication number: US3479014A
Application number: US319429A
Authority: US
Inventors: Frank Ward Reilly; Hoyt William Bozeman
Original assignee: Sherman and Reilly Inc
Current assignee: Sherman and Reilly Inc
Priority date: 1963-10-28
Filing date: 1963-10-28
Publication date: 1969-11-18
Anticipated expiration: 1986-11-18

Description

Nov. 18, 1969 F. w. REILLY ETAL VERSATILE SHEAVE BLOCK Filed Oct. 28, 1963 FIGZ INVENTOR FRANK WARD REILLY T W BOZEMAN fl K i ATTQRNEY HO BY United States Patent 3,479,014 VERSATILE SHEAVE BLOCK Frank Ward Reilly, Lookout Mountain, and Hoyt William Bozeman, Chattanooga, Tenn., assignors to Sherman &

Reilly, Inc., Chattanooga, Tenn., a corporation of Tennessee Filed Oct. 28, 1963, Ser. No. 319,429 Int. Cl. B66d 1/36 US. Cl. 254-193 1 Claim This invention relates to a sheave block and more particularly to such a block which is useful in stringing electric power transmission lines.

In the stringing of electric power transmission lines, there are various requirements necessitating different designs of sheave blocks, depending upon the method of stringing being used. A commonly used method is the stringing of a single transmission line with a single pulling rope. For this type of stringing, an open-side block having a guard which can be latched in open position while the pulling rope is being put into position in the groove of the sheave and then the guard can be latched to form an enclosure with the sheave for the pulling rope and the line is particularly useful. Another type of stringing which is coming more and more into use is stringing by helicopter, especially over difficult terrain, and for this use a partially open block equipped with an outrigger or Wing for guiding the line into the block is most useful. Another type of stringing which is being used more widely as time goes on is the pulling of two, three or four conductors simultaneously with a single pulling line, known in the trade as bundling. The purpose of this type of stringing is to achieve better electrical etficiency in that two or more parallel conductors have a much lower reactance than a single larger conductor of the same electrical conductivity. This is true particularly in the transmission of extra high voltages, which is the modern trend in long transmission line design, the multiple parallel conductors resulting in a lower impedance and much better transmission. In

. stringing such parallel lines, a device known as a running board is used to pull the lines parallel to each other and to guide them into the grooves of the sheave.

Other means of reducing the reactance are being experimented with, such as the so-called hollow or expanded conductor. The hollow or expanded conductor is subject to damage from being twisted and, in some instances, torque arms are used to keep the conductor from rotating. When such torque arms are used, an open-side block is necessary so that the torque arm can pass through the block. Each of these uses has heretofore required a sheave block especially adapted to that use.

One object of the invention is to provide a wire stringing block which is readily adaptable to varied uses.

Another object is to provide a block with an openside frame and a pivoted guard forming an enclosure for a wire.

A further object of the invention is to provide an openside block including means for detachably securing thereto different fittings adapting the block for varied types of uses.

Other objects and advantages of the invention will be apparent from the following description, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a front elevation, partly in section, of a block made in accordance with this invention;

FIG. 2 is a side elevation, partly broken away, showing the guard in closed position, and FIG. 3 is a front elevation, partly in section and partly broken away, of such a block showing the guard in open position and used in connection with an auxiliary frame member to form Patented Nov. 18, 1969 a partially open block, with an extended wing or outrigger for helicopter stringing; and

FIG. 4 is a front elevation, partly in section, of a pair of blocks used in connection with a wire stringing drum for stringing multiple wires.

In the drawings, referring now to FIG. 1, there is illustrated an openside wire stringing block generally designated at 1. This block includes an openside frame 2 preferably made of metal, such as a high strength aluminum alloy, and means 3 attached to the frame for supporting the block from a series of innsulators 4, only one of which is shown attached to a supporting structure, not shown.

A guard 5 is pivotally attached to the frame 2 on a pivot pin 6. A locking pawl 7 is pivoted on a pin 8 and a spring 9 urges its detent 10 into locking engagement with selected notches 11 or 12 or with a shoulder 13. In the full line position of FIG. 1, the guard 5 is held in a closed position, in which it forms an enclosure 14 with the flanges 15 and groove 16 of a sheave 17 and with the inner surface of the frame 2. The guard is locked in the closed position by the spring 9 forcing the detent 10 of the pawl 7 into the notch 11. In this closed position, the guard will restrain the pulling rope and the conductor wire from getting out of the block.

When the block is used for stringing hollow or expanded conductors, using torsion or torque arms, the guard is raised to the position shown in broken lines in FIG. 1, in which position it is held by the force of the spring 9 urging the detent 10 into the notch 12. After the stringing operation has been completed, the guard can be opened to the position shown in broken lines in FIG. 1 or to the fully retracted position illustrated in FIGS. 3 and 4, in which it is held by engagement of the detent 10 with the shoulder 13.

The frame 2 is apertured near its lower end at 18 to receive a hollow pin 19, having a shoulder 20 thereon to stop the pin in the correct position and a flange 21 at its outer end. The pin is held in place in the frame by means of a crosspin 22 passed through aligned openings in the frame and in the hollow pin. A bearing surface 23 is formed between the shoulder 20 and the flange 21 to receive the sheave 17 journaled on the pin.

In connection with the stringing of wire by helicopter, the form of block attachment illustrated in FIG. 2 and 3 is used. In this case, the structure is the same as that in FIG. 1, with the addition of an auxiliary frame member or side piece 24. This side piece supports an outrigger or wing 25 for use in aiding stringing by helicopter, as disclosed fully in the copending application of Delmar C. Sherman, Ser. No. 199,014, filed May 31, 1962, now Patent No. 3,195,862. The auxiliary frame member 24 is attached to the frame 2 by means of a mandril 26 which is adapted to be received in the hollow pin 19. The mandril has an opening 27 which registers with the openings in the frame 2 and in the pin 19 to receive the crosspin 22 and thereby to lock the mandril and the auxiliary frame member 24 in position.

In stringing of a transmission line by helicopter, it is essential to hold the stringing block in line with the wire being strung with its sheave in a vertical position. For this purpose, an orienting or stabilizing bar 28 is used and it may be suitably attached, as by means of a bolt 29 received in a tapped opening 30 in the end of the mandril 26. Stays or ties, not shown, are provided to connect with a tower or H-frame, not shown, and with holes provided in the ends, not shown, of the orienting or stabilizing bar 28. In this use of the block, the guard 5 is not needed and it is swung out of the way and latched in the position illustrated in FIG. 3. In this way, the

3 guard does not interfere with use of the block, but is left attached, so that it cannot become lost.

In the use of the block illustrated in FIG. 4, a central drum 31 is mounted between two blocks spaced from each other, each having a sheave 17 mounted thereon as il lustrated in FIG. 1 and as described in connection therewith. The drum 31 may have a central groove 32 for receiving and guiding the pulling rope. It is quickly assembled with the two blocks by inserting a drum mandril or axle 33 projecting from each end of the drum into the hollow pins 19, which are also shown in FIGS. 1 and 3. As in the case of the form shown in FIG. 3, the mandril 33 is attached by means of the crosspin 22 being passed through openings in the frame 2, in the hollow pin 19 and through an opening 34 in the mandril in registry therewith. As in the case of the form illustrated in FIGS. 2 and 3, the guard 5 is latched back out of the way.

The form illustrated in FIG. 4 is of a two conductor bundle block and it will be readily understood that the central drum 31 can be replaced by other similar drums to provide three-conductor, four-conductor, etc., bundle blocks.

By this invention, there is provided a block which is very versatile in its use for stringing electric power transmission lines. It constitutes a single piece of equipment which can be adapted readily for use in various types of stringing jobs, so that the user need not buy and keep on hand a multiplicity of equipment. The block can be used for the stringing of a single transmission line with a single pulling rope. It can be readily so used with or without torque or torsion arms in connection with the stringing of hollow or expanded conductors to keep the conductors from rotating and being damaged by twisting, the block being an openside block to permit passage of the torque or torsion arms through the block in such use. The block can also be used for stringing of a line by helicopter, providing an outrigger or wing for guiding the line into the block, as described fully in the copending application identified above. In addition, the block can be used in connection with a bundle block for the simultaneous stringing of two, three, four, etc., conductors, with bundle blocks being formed by the use of a cooperating, spaced pair of blocks made in accordance with this invention and central drums, for the purpose of achieving better electrical efiiciency.

It will be apparent to those skilled in the art that various changes may be made in the invention, without departing from the spirit and scope thereof, and therefore the invention is not limited by that which is shown in the drawings and described in the specification as indicated in the appended claim.

We claim:

1. A wire stringing block comprising a frame having an open side, a guard pivoted at one end to the frame, means associated with the guard to hold it in open position, a pin supported by the frame which pin is hollow throughout its length and has a sheave journaled thereon, a mandril received in said pin, the mandril supporting a wire guiding member at one end and a block stabilizing bar at the other end.

References Cited UNITED STATES PATENTS 3,010,700 11/1961 Petersen 254--193 X 3,145,973 8/ 1964 MacFarlane.

3,199,840 8/ 1965 Lindsey 254-192 FOREIGN PATENTS 332,161 5/1914 Germany. 117,046 8/ 1946 Sweden.

HARVEY C. HORNSBY, Primary Examiner US. Cl. X.R. 254-197