US2440427A

US2440427A - Crown block assembly

Info

Publication number: US2440427A
Application number: US572510A
Authority: US
Inventors: Emil A Bender
Original assignee: Individual
Current assignee: Individual
Priority date: 1945-01-12
Filing date: 1945-01-12
Publication date: 1948-04-27
Anticipated expiration: 1965-04-27

Description

E. A. BENDER 2440,27

CROWN BLOCK ASSEMBLY Filed Jan. 12, 1945 2 Sheets-Sheet l E. A. BENDER cnown BLOCK ASSEMBLY Filed Jan. 12, 1945 2 Sheets-Sheet 2 I NVENT 0R [MIL A. BEA/DEE ATTORNEYS Patented Apr. 27, 1948 Emil A. Bender, Bakersfield, Calif.

Application January 12, 1945, Serial No. 572,510

This invention relates to crown block assemblies, and more particularly to" such an assembly which is especially adapted for use on portable drilling rigs.

It is the common practice to provide crown block assemblies at the upper ends of oil well drilling derricks, and a suitable line is reeved around the sheaves of the crown block and 8 Claims. (Cl. 254-145) around the sheaves of the traveling block, one end a of the line being commonly referred to as the "live line and connected to a power driven drum, such as the drum of a drawworks, and the other line being commonly known as the "dead line," the end of which is anchored .to a suitable stationary point. The dead line usually extends downwardly into the derrick and is anchored thereto internally thereof. The live line usually extends downwardly wholly outwardly of the derrick for connection with the winding and unwinding drum. The conventional crown block assembly in which the live line and dead line are arranged as stated, is substantially satisfactory for use on conventional permanent derrick installations, the principal disadvantage lying in the fact that the dead line within the derrick is sometimes in the way in performing the usual functions within the derrick. However, the conventional arrangement is far more disadvantageous in the smaller portable derricks now in rather common use. The disadvantage referred to is even more noticeable in a portable derrick because of the smaller crosssectional size of the derrick. Moreover, portable derricks are much more lightly constructed and the conventional arrangement of the lines is such as to subject the derrick to excessive strains, particularly torsional strains, because of the unequal application of loads to the derrick through the livewand dead lines.

An important object of the present invention is to provide an improved crown block assembly through which both lines may be arranged externally of the derrick, thus avoiding any inter-' ference with workmen operating within the der' rick.

A further object is to provide an improved crown block assembly through which an improved In the drawings 1 have shown one embodiment or the invention. In this showing:

Figure 1 is a plan view of the crown block assembly in place on the upper end of a derric i assembly,

Figure 3 is a diagrammatic perspective view showing the arrangement of the lines with respect to the derrick, and

Figure 4 is a diagrammatic perspective view illustrating the reeving or the lines around the various sheaves.

Referring to Figure 3, the numeral l0 diagrammatically represents in perspective a portable oil well drilling derrick which may be of the type disclosed in the copending application of Robert E. McCarthy and Emil A, Bender, Serial No.

542,552, filed June 28, 1944, now Patent No. 2,413,- 149, granted December 24, 1946. Such derrick is arranged on a base indicated as a whole by the numeral II or preferably T-shape havlnga stem portion l2 and a cross portion [3; The crown block assembly forming the subject matter of the present invention is indicated as a whole by the numeral I 4 and is arranged on the top of the derrick, such top being illustrated in Figure 1 and being indicated by the numeral l5. The derrick top I8 is conventionally formed of structural steel members, including front side and back side members l6 and I! and side members ID.

The crown block assembly It comprises a preferably fabricated supporting structure 20 seated on the front side and back side structural memarrangement of live and dead lines is provided by means of which the derrick is relieved of destructive torsional strains, the loads imposed upon the derrick through the lines being substantially equalizedi Other objects and advantages of the invention will become apparent during the course or the following description.

bers I 8 and H ascshown in Figure 1. The sup-. porting structure 20 may be formed as shown in Figure 2 of an I-beam 2| arranged within a closed beam structure formed of oppositely facing

channels

22 and 23 preferably welded together at their edges. The channel 23 may be bolted as at 24 to the member II.

The supporting structure 20 carries :a pair of upstanding bearings 28 and 2'! supporting a shaft 28 which carries a pair of sheaves 29 and 30-. These sheaves are arranged parallel to the derrick structural members l6 and I1 and preferably centered between the structural members I 8 and equidistantly spaced on opposite sides of the axis of the derrick, indicated by the numeral 3|. As will be explained later, the line which passes around the

sheaves

28 and 30 also passes around the

sheaves

33, 34 and 35 of a conventional traveling block assembly generally designated by the numeral 38.

A live line sheave 38 is carried by a shaft 38 Figure 2 is a rear elevation of the crown block having. its axis arranged Pe pendicular to the axis of the shaft 28. The sheave 30 is supported I beyond the back side of the derrick, that is, the side corresponding to the structural member I! in Figure 1 and corresponding to the base section l2 in Figure 3. i

A deadline sheave 44 is arranged on a shaft 45 parallel to the shaft 88 and supported in

bearings

46 and 41, the former of which is secured to the structural member 18 and the latter of which is secured to the supporting structure 20. It will be noted that the sheave 44 is substantially larger than the sheave 38 and that its axis of rotation is offset inwardly from the axis of the shaft 39. The sheave 38 is so arranged that its inner limit (Figure 1) is slightly toward the back side of the derrick from the sheave 30, while the sheave 44 is so arranged that its forward limit is slightly forward of the sheave 28. As is true of the sheave 38, the sheave 44 overhangs the back side of the derrick, and the purpose of this arrangement will be referred to later.

designates the line passing around the'various sheaves to operate the traveling block 36, The line so has its live" end 5| passing over the back side of the sheave 38 and downwardly for connection with a suitable drum 52, which may be the drum of a drawworks arranged on the base section l2, The line 50 has its "dead line end passing downwardly over the rear of the sheave 44 for connection with a stationary point. such as a stationary connection 53 (Figure 1) carried by the base portion l2. The "live line" extends over the sheave 38 as shown in Figure l thence downwardly as at 55 and around the sheave of the traveling block, then upwardly as at 56 around the sheave 30, then downwardly as at 51 around the traveling block sheave 34, then upwardly as at 58 around the sheave 29, then downwardly as at 59 around the traveling block sheave 33, and then upwardly as at 60 around the sheave N to terminate in the "dead line" 52. It will be noted that both the "live line SI and dead line" 52 are arranged outwardly of the derrick at the back side thereof and extend downwardly generally in the same direction and preferably at approximately the same angle to a vertical plane through the axis of the derrick from the front to the rear thereof. This arrangement assists in equalizing strains on the derrick, as will be further referred to later.

The operation of the apparatus will be rather obvious from the foregoing description.

The traveling block is moved vertically in the derrick from time to time to perform the usual functions which need not be referred to in detail. The turning of the drum 52 in one direction will wind the live line" 5: thereon, thus causing the line 50 to move around the various sheaves and provide the necessary leverage for operating the traveling block, Conversely, rotation of the drum 52 in the opposite direction downward passage of the line 2 and around the traveling block 35, while the inner limit of the sheave 44 is arranged for the direct passage of the line from the traveling block sheave 33 to the sheave 44. The plane of the traveling block sheave 34 is preferably midway between the planes of the

crown block sheaves

29 and 30. This arrangement permits the line 50 to be readily reeved around the various sheaves. The relative positions of the various sheaves will be apparent from Figure 1, the traveling block sheaves bein shown in dotted lines in such figure.

As is well known, it has been the common practice to use a crown block sheaving arrangement substantially different from the present one, and the dead line, which has its end anchored, is conventionally extended downwardly into the interior of the derrick and connected thereto near the bottom thereof. Except that the presence of such line within the derrick somewhat interferes with the work which must be carried on within the derrick, such arrangement is not particularly disadvantageous or serious when used with a conventional permanent derrick which is relatively heavy and of great structural strength. However, relatively light portable derricks have come into quite common use, and such derricks are necessarily much lighter in construction than the permanent derricks referred to, They are also substantially smaller in horizontal section, and a. dead line" arranged Within such a. derrick causes more interference than is true of such a line within a derrick of larger cross-sectional area. With the present crown block arrangement, the dead line is arranged wholly externally of the derrick where it can cause no interference with the work to be performed within the derrick.

Even more important from a practical standpoint is the fact that the conventional dead line arrangement subjects the derrick to unequal strains, particularly torsional in nature, and forces are exerted both upwardly and downwardly. The present crown block assembly, with both the dead line" and live line arranged externally of the derrick in the manner shown in Figure 3, eliminates the exertion of upward strains on the derrick through the "dead line," since the latter is permitted to be connected to the base rather than to the derrick proper. Moreover, downward strains exerted at the top of the derrick are equalized, these strains being substantially directly vertical and all torsional strains being eliminated. A relatively light portable derrick, therefore, possesses ample strength to withstand the strains to which it is subjected.

The line ends 51 and 52 need not be parallel to each other, but it is preferred that they be parallel to or diverge or converge downwardly at equal angles with respect to a vertical plane through :the axis of the derrick from the front side to the back side thereof, that is, parallel to the sides l8. The present construction permits such an arrangement and results in almost perfectly equalizing all strains to which the derrick is subjected, and particularly the destructive torsional strains.

It also will be noted that the supporting structure 20 extends throughout the width of the derrick from front to back thereof, and such structure protects the

sheaves

29 and 30 from possible injury by excessive upward movement of the traveling block. The structure 20 defines the upper limit of movement of the traveling block and when such limit is reached, the force exerted by the traveling block will be absorbed by the

sheaves

29 and 30.

It is to 'be understood that the form of the invention herewith shown and described is to be taken as a. preferred example of the same and that various changes in the shape, size and arrangement of parts may be resorted to which do not depart from the spirit of the invention or the scope of the subioined claims.

line and dead line sheaves and around which said line passes.

2. A crown block assembly for a derrick having a front side and a back side, a traveling block, and an operating line therefor, said crown block assembly comprising a plurality of sheaves around which said line is adapted to be reeved, said plurality of sheaves including a live line" sheave and a dead line" sheave arranged parallel to each other and arranged with their forward extremities in a position for the passage of said line directly downwardly to certain sheaves of the traveling block, the back side extremities of said dead line and said "live line sheaves both extending beyond the back side of the top of the derrick to provide for the downward extension of both ends of said line externally of the derrick, said plurality of sheaves furtherincluding a sheave between and perpendicular to said live line and "dead line" sheaves and around which said line passes.

3. A crown block assembly for a derrick having a front side and a back side, a traveling block,

' and an operating line therefor, paid crown block assembly comprising a structural member arranged on and secured tothe top of the derrick and extending from the front side to the back side thereof, a plurality of parallel sheaves arranged above and supported by said structural member transversely thereof, said sheaves being positioned for the passage of said line therefrom to the traveling block for raising and lowering such block, and a dead line" sheave and a "live line sheave over which said line is adapted to pass, both of said last named sheaves extending beyond the back side of the top of the derrick whereby the ends of said line are arranged externally of the derrick. a

4. A crown block assembly for a derrick having a front side and a back side. a traveling block, and an operating line therefor, said crown block assembly comprising a structural member ar-- ranged on and secured to the top of the derrick and extending from the front side to the back side thereof, a plurality of parallel sheaves arranged above and supported by said structural member transversely thereof, said sheaves being positioned for the passage of said line therefrom to the traveling block for raising and lowering such block, and a dead line sheave and a "live line sheave over which said line is adapted to pass, both of said last named sheaves extending beyond the back side of the top of the derrick whereby the ends of said line are arranged externally of the derrick, said "dead line" and live .line" sheaves being parallel to each other and perpendicular to said plurality of sheaves and having their extremitiestoward the front side of the derrick positioned for the direct passage -ofsaid line therefrom to certain sheaves of the traveling block.

5. A crown blqck assembly for a derrick having a front side alnd a back side, a traveling block. and an operatingiline therefor, said crown block assembly comprising a rigid structural support arranged on and fixed to the top of the derrick and extending from the front side to the back side thereof, a pair of bearings carried by the top of said structural support, a shaft carried by said bearings, a. plurality of sheaves carried by said shaft and arranged parallel to each other and transversely of said structural support, said sheaves being positioned for the direct extension of said line therefrom to the traveling block for raising and lowering such block, bearing means carried by said structural support and by the top of the derrick, a pair of shafts carried by said bearing means, and a live line sheave and a dead line sheave carried by the respective latter projecting beyond the back side of the top of the derrick for the direct downward extension of the ends of said line externally of the derrick.

6. A crown block assembly for a derrick having a front side and a back side, a traveling block, and an operating line therefor, said crown block assembly comprising a rigid structural support ar-,- ranged on and fixed to the top of the derrick and extending from the front side to the back side thereof, a pair of bearings carried by the top of said structural support, a shaft carried by said bearings, a plurality of sheaves carried by said shaft and arranged parallel to each other and transversely of said structural support, said sheaves being positioned for the direct extension of said line therefrom to the traveling block'for raising and lowering such block, bearing means carried by said structural support and by the top of the derrick, a pair of shafts carried by said bearing means, and a live line" sheave and a. "dead line sheave carried by the respective latter shafts, said live line and "dead line sheaves projecting beyond the back side of the top of the derrick for the direct downward extension of the ends of said line externally of the derrick, the shafts of said 1ive line" and "dead line" sheaves being parallel and offset from each other and said dead line sheave being substantially larger than said live line sheave whereby both of said sheaves have their back side extremities lying substantially in a common vertical plane with the front extremity of said dead line sheave extending approximately to the sheave of said plurality of sheaves toward the front side of the derrick and with the front side extremity of the live line sheave extending approximately to the sheave of said plurality of sheaves nearest the back side of the derrick.

7. In combination with a derrick having a front side and a back side, abase extending horizontally therefrom, a traveling block arranged within the derrick and having a plurality of sheaves, and an operating line for said traveling block, a crown block assembly comprising a plurality of parallel sheaves supported on the top of the derrick in planes parallel to the front side and back side of the derrick and from which said line is adapted to pass directly to certain sheaves of the traveling block. and a "dead line sheave and a "live line" sheave arranged parallel to each other and per.- pendicular to said first named sheaves and extending horizontally beyond the back side of the derrick whereby the ends of said line are adapted to extend downwardly from the top of the derrick wholly externally or the derrick, the "dead line" and of said sheave being fixed to the base of the derrick.

8. In combination with a derrick having a front side and a back side, a base extending horizontally therefrom, a traveling block arranged within the derrick and having a plurality of sheaves, and an operating line for said traveling block, a crown block assembly comprising a plurality of parallel sheaves supported on the top of the derrick in planes parallel to the front side and back side of the derrick and from which said line is adapted to pass directly to certain sheaves of the traveling block, a dead line sheaveand-a "live line sheave supported on the top of said derrick parallel to-each other and perpendicular to said plurality of sheaves, said dead line and "live line" sheaves having their back side extremities extending-beyond, the back side of the derrick and their front side extremities arranged for the passage of said line thereover and downwardly to certain of said traveling block sheaves to be reeved therearound, the dead line end of said operating line being fixed to the derrick base,

and-a drum for winding and unwinding the live line" end of said line, the live line and dead line" ends of said operating line being arranged at approximately equal angles to a vertical plane passing through the axis of the derrick from the front side to the back side thereof.

\ Em A. BENDER.

REFERENCES CITED.

The following references are of record in the file of this patent:

UNITE) STATES PATENTS Number Name Date 1,414,795- Suman et al May 2, 1922 2,293,958 Woolslayer et al. Aug. 25, 1942 2,359,919 Johnson Oct. 10, 1944