US3472395A

US3472395A - Crossarm gin

Info

Publication number: US3472395A
Application number: US684831A
Authority: US
Inventors: David C Hubbard; James K Harper
Original assignee: AB Chance Co
Current assignee: AB Chance Co
Priority date: 1967-11-21
Filing date: 1967-11-21
Publication date: 1969-10-14
Anticipated expiration: 1986-10-14

Description

D. c. HUBBARD ET A 3,472,395

GROSSARM GIN Filed Nov. 21, 1967 INVENTORS. Dav/d C. Hubbard James K. Harper United States Patent 3,472,395 CROSSARM GIN David C. Hubbard and James K. Harper, Centralia, M0., assignors to A. B. Chance Company, Centralia, Mo., a corporation of Missouri Filed Nov. 21, 1967, Ser. No. 684,831 Int. Cl. B66c 23/18 US. Cl. 212-8 7 Claims ABSTRACT OF THE DISCLOSURE A gin pole for a utility crossarm is provided with a pair of opposed lift rings at its upper end and, at its lower end, is provided with base structure which is adjustable to accommodate crossarms of varying widths and depths. For width adjustment, the base structure includes a pair of depending, reversible legs which receive the crossarm, each of the legs having an offset therein to provide a total of three possible leg spacings. A locking pin spans the lowermost extremities of the legs and is adjustable to accommodate various crossarm depths. The base structure also includes a ferrule having a convex lowermost bearing surface which engages the upper surface of the crossarm and permits the pole to be rocked from side-to-side between two operative positions where the pole leans in opposite directions.

Wooden crossarms for line poles of electrical power transmission systems are of various widths and depths ranging from distribution to subtransmission applications. In the lifting of conductors onto support insulators carried by the crossarms, a hoist line is commonly employed in conjunction with a gin pole temporarily mounted on the crossarm structure.

Heretofore, it has been necessary for work crews to have a number of gin poles provided with supporting bases of various sizes to accommodate the range of crossarm sizes utilized in a particular system, Furthermore, in a two conductor system, for example, the gin pole is mounted on the crossarm between the two support insulators and leans to one side to provide the necessary clearance for the working of one of the insulator positions. Subsequently, it is necessary to remove the gin pole from the crossarm, reverse and remount it in order to work the other insulator position.

It is, therefore, the primary object of this invention to provide an improved gin pole for utility crossarms which is capable of accommodating crossarms of various widths and depths.

As a corollary to the foregoing object, it is an important aim of the instant invention to provide a gin pole for utility crossarms which permits two insulator positions to be worked without removing the gin pole from the crossarm and remounting the same.

In the figures:

FIGURE 1 is a front elevational view of a portion of a utility crossarm and the gin in place thereon, the alternate position of the gin pole being illustrated in broken lines;

FIG. 2 is an enlarged, side view of the base of the gin pole, one of the legs of the yoke being revealed in longitudinal section;

FIG. 3 is a sectional view taken along line 33 of FIG. 2; and

FIG. 4 is a cross-sectional view of the mast looking in the direction of the base thereof.

A utility crossarm of the wooden type is shown fragmentan'ly in FIG. 1 and has a pair of support insulators 12 and 14 mounted thereon and spaced longitudinally of crossarm 10. A gin pole 1-6 is shown in place on ice crossarm 10 and includes an insulated, rod-like mast 18 having its upper end telescoped within a top ferrule 20 and secured thereto. The top ferrule 20 is provided with a pair of

opposed lift rings

22 and 24 presenting a pair of eyes 26 and 28 respectively.

Mast 18 is shown leaning to the right in FIG. 1 with its lift ring 24 directly above insulator 14, a pulley 30 being suspended from ring 24 and receiving a hoist line 32. The hoist line 32 terminates in a hook 34 through which a conductor 36 extends, it being understood that, in the illustration of FIG. 1, conductor 36 has been lifted by hoist line 32 to the position shown. where it is ready to be lowered onto insulator 14.

The base structure of gin pole 16 is shown in detail in FIGS. 2-4. A yoke 38 is secured to the lower end of mast 18 and comprises a bight portion in the form of a base ferrule 40 in which the lower end of mast 18 is received. (In both the top ferrule 20 and the base ferrule 40, means such as crosspins may be utilized to lock the two ferrules to the mast 18.) The yoke 38 further includes a pair of depending side plates or legs 42 each having a pair of holes 44 therein for receiving a locking pin 46. The two holes 44 in each leg 42 are disposed adjacent the lowermost end thereof and are aligned with corresponding holes 44 in the other leg 42 to provide two possible positions for the locking pin 46. It should also be noted that the holes 44 of each leg 42 are spaced along the longitudinal axis of the leg 42, the longitudinal axes of both of the legs 42 being in a common plane with the longitudinal axis of the mast 18.

Base ferrule 40 is provided with two pairs of diametrically opposed, tapped bosses 48, the upper end section of each leg 42 being provided with a pair of longitudinally spaced openings into which a pair of bolts 52 are inserted and threaded into the corresponding tapped bosses 48. A 45 offset 54 is formed in each leg 42 just beneath the upper section 50 thereof as is clear in FIG. 2, the remaining lower section 56 thus being laterally offset with respect to the upper section 50.

The base ferrule 40 is provided with a convex lower bearing surface 58 which is arcuate in configuration and presents a pair of laterally spaced bearing areas 60. As may be seen in FIG. 1, one of the bearing areas 60 rests against the upper surface of crossarm 10, while the locking pin 46 engages the undersurface of crossarm 10.

In order to provide structural strength together with high dielectric strength, it is preferred that mast 18 comprise a tubular outer wall 62 (FIG. 4) of synthetic resin material filled with a cylindrical core 64 composed of a solidified unicellular foam resin. The details of suitable materials forthe preferred construction of mast 18 may be had by reference to Fink, Us. Letters Patent No. 2,997,529, entitled Electrical Insulating Rod, granted Aug. 22, 1961, and owned by the assignee herein.

In utilizing the instant invention, it will be appreciated from FIG. 2 that the two legs 42 are reversible to provide a base structure for mast 18 which may be varied in width to accommodate the width of a particular crossarm 10. Three possible widths are provided, the intermediate width being represented by the solid line illustrations of legs 42 in FIG. 2. The greatest spacing between legs 42 is obtained by reversing the right-hand leg 42 so that its lower section 56 is disposed as indicated by the broken lines; this is readily accomplished by releasing the bolts 52, reversing the right-hand leg 42, and reinserting bolts 52. In similar fashion, with the right leg 42 in the solid line position, the minimum spacing between the legs 42 is provided by reversing the left-hand leg 42 to place its lower section 56 in the broken line position illustrated.

Besides accommodating crossarms of different Widths,

the two positions provided for locking pin 46 enable the instant invention to also accommodate crossarms of different depths. Manifestly, additional holes 44 may be provided if desired. The arrangement illustrated is particularly adapted for crossarms from 3 /2" x 4 /2" to 4%" x 5%.

With the legs 42 set for the width of crossman and locking pin 46 removed, the gin pole 16 is placed on the crossarm 10 as illustrated in FIG. 1 and locking pin 46 is inserted. Assuming that the right-hand insulator position (insulator 14) is to be worked first, the mast 18 is leaned to the right as illustrated, whereupon the righthand bearing area 60 (as viewed in FIGS. 1 and 3) rests upon the upper surface of crossarm 10. A guy line 66 is shown attached to lift ring 22 for the purpose of back guying gin -pole 16 to reduce the cantilever strain and the tendency of the crossarm-engaging bearing area 60 to crush the wood fibers of the crossarm.

After the right-hand insulator position is worked, it is only necessary that the hoist be removed from ring 24 and the guy line 66 detached, whereupon the gin pole 16 is shifted to its broken line position by simply rocking the same to the left until the left-hand bearing area 60 engages the upper surface of crossarm 10. Lift ring 22 is now directly above insulator 12 to permit the left-hand insulator position to be worked. Therefore, reversing and remounting of the gin pole 16 is obviated, and no readjustment of the locking pin 46 is necessary when changing positions since the holes 44 are on the longitudinal axes of the legs 42 and provide the same depth adjustment for each operating position.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

-1. A crossarm gin pole comprising:

a mast having an upper end and a lower end;

means on said upper end for supporting a hoist line;

and

base structure on said lower end for engaging a crossarm to support the mast thereon for movement from side-to-side between a pair of operative positions where the mast leans in opposite directions,

said structure including a pair of depending legs receiving the crossarm therebetween when the mast is supported on the crossarm,

at least one of said legs having an offset and being reversibly secured to said lower end of the mast, whereby the spacing between the legs may be adjusted to accommodate crossarms of different widths.

2. A crossarm gin pole comprising:

a mast having an upper end and a lower end;

means on said upper end for supporting a hoist line;

and

base structure on said lower end for engaging a crossarm to support the mast thereon in a leaning position,

3. The invention of claim 2,

said structure including a yoke having a bight rigid with said lower end of the mast,

said yoke presenting said legs and having fastener means releasably securing the legs to the bight.

4. The invention of claim 3,

said mast being of structurally strong, insulating material,

said bight comprising a ferrule receiving said lower end of the mast,

each of said legs having an upper section engaging said ferrule and releasably secured thereto by said fastener means, a lower section below the ferrule, and an intermediate connecting portion integral with the upper and lower sections and presenting said offset, whereby to provide three possible widths between said legs.

5. In combination with a crossarm, a gin pole comprising:

a mast having an upper end and a lower end;

means on said upper end for supporting a hoist line;

and

base structure on said lower end provided with a downwardly facing surface in overlying engagement with said crossarm to support said mast thereon for rocking movement with said structure from side-to-side between a pair of operative positions of the mast Where the latter leans in opposite directions,

said surface having a pair of laterally spaced bearing areas which are alternately brought to bear against said crossarm as said mast is rocked between said positions.

6. The invention of claim 5,

said structure including a pair of depending legs receiving the crossarm therebetween and projecting downwardly therefrom; and

lock means spanning said legs beneath the crossarm to limit the degree of lean of the mast in either of said directions.

7. The invention of claim 5,

said structure including a pair of depending legs receiving the crossarm therebetween and projecting downwardly therefrom,

said legs extending longitudinally of the mast and having a plurality of aligned holes therein along the longitudinal axes of the legs; and

a locking pin spanning said legs beneath the crossarm and received in a selected aligned pair of said holes, whereby to accommodate crossarms of different depths.

References Cited UNITED STATES PATENTS 2,665,012 1/1954 McCain 2l28 2,728,462 12/1955 Fincher 2128 3,064,824 11/1962 Beatty 212-8 EVON C. BLUNK, Primary Examiner H. C. HORNSBY, Assistant Examiner