US2766009A - Crown block sheave arrangement - Google Patents

Description

Oct. 9, 1956 J. H. WILSON 2,766,009

CROWN BLOCK SHEAVE ARRANGEMENT Filed Oct. 5, 1954 3 Sheets-Sheet 1 Inventor John Hart Wilson Oct. 9, 1956 J. H. WILSON 2,766,009

CROWN BLOCK SHEAVE ARRANGEMENT Filed Oct. 5, 1954 a Shets-Sheet 2 In 7 .-I

I8 I 7 14 Inventor '1 John Hart Wilson *7 if v #0 Oct. 9, 1956 J. H. WILSON CROWN BLOCK SHEAVE ARRANGEMENT 3 Sheets-Sheet 3 Filed 001;. 5, 1954 Patented Oct. 9, 1956 CROWN BLOCK SHEAVE GEMENT John Hart Wilson, Wichita Falls, Tex. Application October 5, 1954, Serial No. 460,477 2 Claims. (Cl. 254-145) This invention relates to improvements in crown blocks for masts or the like, which are used in connection with rotary well drilling rigs, and with well servicing units.

The device embodying the present invention is so designed that the axis of the traveling block is perpendicular to the front side of the mast, thereby presenting a traveling block which has one of the flat sides thereof toward the derrick man on the racking platform, thereby minimizing the danger of his becoming entangled in the moving cables as the traveling block raises and lowers the drill stem, pipe or the like. Also, this arrangement of the traveling block permits the derrick man to get nearer to the center of the pipe and thus reducing the distance he must reach to attach and unlatch the pipe elevators.

Heretofore, it has been the practice to use crown blocks wherein the axis of the traveling block was parallel with the front side of the mast pole, which arrangement resulted in the live running cables being adjacent the derrick man, or with the axis of the traveling block at an acute angle with respect to the front of the mast, which presented a corner of the traveling block toward the derrick man, thereby presenting an awkward situation for the derrick man to work with the elevators and the block without becoming entangled in the cable.

In the present invention, the traveling block moves up and down the mast with the fiat side of the block toward the derrick man, therefore, he may easily move the elevators which hang from the block, without being in danger of the moving cables or the block.

An object of this invention is to provide a traveling block wherein the block will always hang with the axis thereof perpendicular to the front of the mast, or the side on which the derrick man may be working, thereby minimizing the danger of his becoming entangled within the cables, and permitting him to safely stand closer to the pipe.

Another object of this invention is to provide a sheave arrangement whereby the sheave of the fast line is at an angle so it will point to the center of the winding drum.

A further object of this invention is to provide a crown block, the sheaves of which are of varying diameters, with the fast line sheave being the larger, and the dead line sheave being smaller.

A still further object of this invention is to provide a crown block for a rotary drilling rig or for a well servicing unit, wherein the traveling block sheaves are so arranged that they will align the axis of the traveling block substantially with the center of the hole, and at the same time, a sand line sheave is provided intermediate the crown block sheaves so the center of the groove of the sand line sheave is substantially in a vertical plane passing through the center of the bore hole of the well, but slightly to the rear thereof.

Yet another object of the invention is to provide a crown block assembly whereby the fast line and the normal dead line may be attached to the winding drum,

and the speed of the traveling block doubled, when desired.

A still further object of the invention is to provide a crown block assembly in which the sheaves are so arranged that the center of gravity of all the forces acting on the top of the mast is substantially the same as the center of gravity of the mast supporting structure in which all the legs are the same size structural members.

With these objects in mind and others that will manifest themselves as the description proceeds, reference is to be had to the accompanying drawings in which like reference characters designate like parts in the several views thereof, in which:

Fig. 1 is an elevational view of the front of the crown block of the mast, with portions of the mast being broken away;

Fig. 2 is a view similar to Fig. 1 but taken from the side thereof;

Fig. 3 is a top plan view of the crown block, showing the sheave arrangement, and showing a portion of the mast upon which the crown block is mounted;

Fig. 4 is a diagrammatic, top plan view showing the sheave arrangement of the crown block and showing the traveling block and the manner in which the cables pass therearound and therethrough, and showing portions of the mast legs in cross-section;

Figure 4A is a fragmentary view corresponding to Figure 4, but showing both the fast line and the normally dead line attached to the winding drum.

Fig. 5 is a horizontal, cross-sectional view through the traveling block taken from above and looking down thereupon;

Fig. 6 is a side elevational view of a sheave mounting and a sheave, with parts broken away, and with one of the covers shown in raised position, of a typical sheave mounting on the crown block;

Fig. 7 is a top, diagrammatic view of a four line pulling arrangement of the crown block sheaves, showing the traveling block in relative position thereto, in dashed outline; and

Fig. 8 is a horizontal sectional view through a two sheave traveling block, as shown in Fig. 7, and showing the sheaves therein.

With more detailed reference to the drawing, of the form of the invention as shown in Figs. 1 through 6, the numeral ll designates generally a structural steel, fabricated mast of a drilling rig or the like having header beam members 2 on the upper ends of the legs of the mast. A pair of brackets 4 are mounted on the upper face of the header beams 2, which brackets mount a shaft 5, near the upper end thereof so as to support a sheave pulley 6, of the crown block, at an angle so that the groove thereof will be directed substantially in alignment with the center of the drilling rig drum. The front face of the groove of the sheave pulley 6 will be substantially over and tangential with the face of the traveling block sheave pulley 7, which is mounted within the traveling block 11. The opposite face of the traveling block sheave pulley 7 is in a perpendicular plane below the face of the crown block sheave pulley 8, which is mounted on brackets, which brackets 9 have a shaft 9a passing therethrough and through the sheave pulley 8. The crown block sheave pulley 8 is also at an angle divergent to the crown block pulley 6. The opposite face of the crown block sheave pulley 8 is substantially tangential to and vertically above one face of the traveling block sheave 10.

The opposite face of the traveling block pulley 10 is substantially in vertical alignment with a face of the crown block sheave pulley 12, which sheave pulley 12 is mounted on brackets 13 and one of the brackets 9. A shaft 13a passes through brackets 13 and one of the brackets 9 and journals the sheave 12 thereon.

The opposite face of the groove of the crown block pulley 12 is substantially above and in perpendicular alignment with one face of the sheave pulley 14 of the traveling block 11. The sheaves 7, 1i), and 14, of the traveling block 11, are journaled on shaft 15. The opposite face of the sheave pulley 14 is substantially in perpendicular alignment with a face of the groove of crown block pulley 16, which sheave pulley is mounted on brackets 17, the brackets 17 having a shaft 17a passing therethrough and on which shaft the sheave pulley 16 is journalled. The cable 18 passes over sheave pulley I6 and downward to an anchor point at the lower end of the mast, in a manner well understood in the art, or the cable may be secured to the drum, as shown in Figure 4A, and both lines pulled simultaneously, so as to produce more rapid movement of the traveling block without changing the line string-up.

A sand line sheave 20 is mounted on upstanding brackets 22, which brackets have a shaft 24 passing therethrough near the upper ends thereof so as to journal the sheave 2i) thereon. A cable 26 passes over the sheave 20, one end of which cable is in substantial alignment with the center of the winding drum while the other end depends downward substantially in alignment with the bore hole thereunder.

The crown block pulleys 6, 8, 12, 16, and 2% have covers 28, 39, 32, 34, and 36, respectively, which are hinged with double hinges at 35, 40, 42, 44, and 46, respectively, so as to enable the cover plates to be raised to facilitate the threading of the cable into the grooves of the respective sheaves.

Pairs of side plates 43, 5'0, 52, 54, and 56 are provided to be positioned, one on each side of the respective sheaves 6, 8, 12, 16, and 213 of the crown block, so as to enclose the sides and upper portion of the sheaves to prevent the workmen becoming entangled in the respective cables 18 and 26, as they work on top of the mast.

Operation When threading up the device, the cable 18, which is known as the fast" line, leading from the hoisting drum is passed over the back side of sheave pulley 6, of the crown block, thence downward beneath sheave pulley 7 of the traveling block and upward over the sheave pulley 8 of the crown block, thence downward and under sheave pulley 19 of the traveling block, thence upward over sheave pulley 12 and downward beneath sheave pulley 14, thence upward over sheave pulley 16 with the cable 18 passing downward to an anchor point A at the lower end of the mast, or the cable 18 may be anchored to the drum, so both cables wind simultaaneousiy, when light loads are hoisted.

it is to be pointed out that the sheave pulley 6 is comparatively large, and since the cable 13 travels at a high rate of speed, the sheave pulley 6 will revolve comparatively slowly. The sheave pulleys 6 and 8 are comparatively large and rotate at a comparatively slow speed, which reduces the rate and amount of wear both on the line, and on the sheaves. The pulley 12 is smaller than the pulleys 6 and 3, but since this pulley travels at a much slower speed, little wear is accorded to the sheave or to the cable passing thereover. By having the sheave sizes arranged in this manner, that is, with the larger sheaves 6 and 8 utilized on the faster lines, and the smaller sheave 12 utilized on the slower lines, the Wear on the sheaves and cables is minimized.

The sheave 16 is normally a dead pulley, and is positioned at a point to correctly center the cable over the blocks and to convey it to an anchor point in the lower part of the mast, when a dead anchor A is used, however, when it is desired to pull light loads at high speed, both ends of the cable 18 may be attached to the winding drum, whereby the pulley 16 becomes a live pulley.

By the present arrangement of the crown block pulleys, the traveling block is always maintained in the correct working position for the workmen, thereby minimizing the dangers incident to working in close proximity to fast moving cables, and the cables passing outward to the winding drum point toward the center of the winding drum.

While the form of the invention, as shown in Figs. 1 to 4, inclusive, depict a crown block using one sand line sheave and four crown block sheaves, over which crown block sheaves a cable passes to support the traveling block 11, it is to be understood that additional sheaves, such as indicated at 12, may be mounted on the crown block, and be interposed in parallel relation, so that the additional sheaves, similar to the sheave 12, occupy an adjacent position to the sheave 12 intermediate the sheave 2.3 and the sheaves 16 and 20. In this manner traveling blocks of greater line capacity, such as eight or more lines, may be utilized, and the traveling block, such as the traveling block 11, will maintain the flat side thereof toward the derrick man at all times.

With the sheave arrangement, as shown in Figs. 1 through 4, the center of gravity of all the forces acting on top of the mast, including the pull of all the lines, includin the back guy lines, is indicated by a circle and designated by the numeral 58, Fig. 4. It can be seen that the center of gravity of these forces is very close to the center of gravity of the mast section, which means that the load is shared relatively equally by the four legs of the mast, which results in maximum load capacity, while utilizing the same size and kind of material for all legs.

The sheave mounting, as shown in Fig. 4-, permits the sheaves to be shifted and aligned with the particular points and welded in place on the header block 2, so that the cable passing outward from the sheave to the winding drum and downward to the traveling block is so aligned with the winding drum and the groove of the traveling block, that minimum wear on the side flanges of the sheaves is accorded, and by having the sheaves thus arranged on mountings, which are located on the particular location, as shown, on top of the mast, so that the center of gravity is located so that the load will be substantially equal on all legs of the mast, thereby enabling all legs of the mast to be made of the same side structural material, and with the load equally distributed on all legs, a much greater load can be raised on a mast of lighter weight construction, than if the center of gravity were located at some other point, which would cause the load to be distributed unequally on the legs.

As shown in Fig. 4, the cable 18 passes off the pulley 6 and points substantially to the center of the winding drum D positioned at a distance outward from the mast, however the distance the winding drum is from the mast varies in accordance with the size of the rig, and other factors, therefore the included angle, designated at a, usually varies from five degrees to fifteen degrees, depending on the distance rearward from the mast the drum is mounted. The sheave 6 may be rotated about the point 7, which is the downwardly extending point of the cable 18, until the sheave 6 is in alignment with the center of the winding drum D. It will therefore, be seen that a sheave mounting, as shown in Fig. 4, may be readily positioned at the particular angle, to align the sheave with the drum and onto the traveling block, so as to maintain the traveling block with the flat side thereof toward the man working in the mast, and at the same time, direct the cable outward to the winding drum D.

Modified form of invention Fig. 7 discloses a modified form of invention, which utilizes one sand line sheave 161 and three crown block sheaves 102, 1-94, and 1-86. It is to be pointed out that these sheaves are mounted on top of the mast 1il3-105 in a manner similar to that shown in Figs. 1, 2, and 3, however, the present sheave arrangement is strung up for a four line block designated at 103, which will maintain the block 108 with the flat side thereof to the derrick man, as will best be seen in Figs. 7 and 8. In this form of the invention the sheaves:- are arranged so that the center of gravity will be as indicated by the circle at 110. The traveling block is shown to have two sheaves 112 and 114 which are journaled on shaft 116.

The sheaves are each constructed in a manner similar to the sheaves shown in Fig. 4 and are arranged so that the fast line 11% will be within a vertical plane passing transversely through the center of the winding drum and with the sheaves arranged in this manner, the base 4 of the sheave mounting is welded to the header beams 2 of the crown block, in the manner as shown in Figs. 1 through 3.

With the sheaves arranged as shown in Fig. 7, and with the fast line passing over sheave 102 and thence downward beneath sheave 114 in traveling block 108, thence upward over sheave 104 which is angularly disposed so that one perpendicular face will be in alignment with a plane passing medially through the groove of pulley 114 and the other face will lie in a plane which passes medially through the groove of sheave 112 of the traveling block 108, and with the cable 118 passing beneath the pulley 112, thence upward and over pulley 106, one face of which groove lies in the vertical plane cutting medially through the groove in sheave 112, the cable 118 then passes downward either to a dead line anchor point A or to an anchor point on the winding drum, depending on the service required of the device.

With the cable 118 anchored to a dead line anchor point, the traveling block 108 will move upward and downward in response to a pull on the fast line 118, in the same manner as any four line sheave arrangement, however, by connecting the dead end of the cable that passes over sheave 106 to a winding drum, the block 108 is raised approximately twice as fast, but it will lift only about one-half the load weight as the aforementioned arrangement.

While the invention has been described in some detail in two forms thereof, it has been pointed out that other arrangements of sheaves may be had, which will give the advantages of the present invention, with the use of any number of sheaves.

Having thus described the invention, what is claimed is:

1. In a crown block arrangement for a drilling mast or the like used in combination with a winding drum on which a cable is wound, a first crown block sheave having its axis of rotation substantially normal to a line joining said sheave and the axial midpoint of said drum, said cable extending from said drum over said sheave, a travelling block having at least two sheaves parallel to each other and to the flat sides of said block, a second crown block sheave mounted in a plane joining opposite horizontally extreme positions of the grooves of two adjacent travelling block sheaves, and a further crown block sheave mounted in a vertical plane and having a horizontally extreme position of its groove in a vertical plane substantially parallel to a horizontal element of the front of said mast and containing one of said opposite h0ri zontally extreme positions of said travelling block sheave grooves, the other of said opposite extreme positions being in a plane substantially parallel to said horizontal element of the front of said mast and containing the horizontally extreme position of the groove of said first crown block sheave on the edge thereof opposite said winding drum, said cable extending from said first crown block sheave to a travelling block sheave thence to said second crown block sheave thence to a second travelling block sheave thence to said further crown block sheave, thence to an anchor point, whereby all runs of said cable between sheaves lie in planes substantially parallel to said horizontal element of the front of said mast.

2. A device as defined in claim 1, said travelling block having three sheaves, said device including a crown block sheave mounted in a plane parallel to the plane of said second crown block sheave and joining opposite horizontally extreme positions of the second and third travelling block sheaves.

References Cited in the file of this patent UNITED STATES PATENTS

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