US2191681A - Derrick construction - Google Patents

Description

Feb. 27, 1940. L. A. RAWSON 2,191,681

DERRICK CONSTRUCTION Filed Sept. 21, 1938 m VENTOR A 65//'@. A Pam/son A T TORNE Y Patented Feb. 27, 1940" UNI ED STATES PATENT OFF-ICE zJaneai I a l Application September 21, 1938, serial N0. 230,977

100mm. (CL 9188-18) This invention relates generally to derrick 'construetions o! the type used in conjunction with oil or gas wells.

It is a general object of the invention to aflord s a derrick or simple design, which can be erected without undue expense, and which will aiiord a greatly increased amount of operating room within the derrick for the racking of pipe.

It is a further object of the invention to aflord i a derrick as described above. without materially departing irom the stress distribution encountered in derricks of conventional design.

Additional objects of the invention will appear from the following description in which the =pre-' .ll ferred embodiment of the invention has been set forth-in detail in conjunction with the accom panyins drawins- Referring tothe drawing:

Fig. 1 is a side elevational view, mum-nun: a

56 derrick incorporating the present construction.

Fig. 2 is a cross-sectional view taken along the line 2-1 of Fig. l. I Fig. 3 is an enlarged detail in perspective, illustrating the manner in which the cross bracing g; on atleast one side of the derrick is oflset lat-' erally, and attached to the remainder of the structure The present invention can be applied to a variety or derricks wherever it becomes desir- 30 -to'aiiordanincreasedamount 01 operating space within the structure. The drawing, however, illustrates a steel derrick of the combination type. and the increased amount of operating space inthis instance has been ggaitordeduponwhatiseommonlyreierredtoas thefiadder side.

Todescribe the 71- lcture as illustrated in the adesignthereisalimitedamountofwentint' room within the derrick which is available for the racking oi. pipe as Accordingtothe presentinventioninplaeetoi' applying the girts and tire cross-bracing in the cusomary manner, these members are displaced laterally on at least one side of the derrick, in this instance the-right hand side as viewed in Figs.

1 and 2. Thus a number of the girts II on op- 5 posite sides 01' the derrick are made of increased length to aiIordthe extensions a. The girts lia which in a conventional construction would extend directly between uprightmembers ill and It, are now attached to the ends oi extensions Ila so as to provide a windowor opening through the derrick side.- The cross-bracing its is also v displaced to the general plane-of the girts 150., and as an added reinforcement the ends of the extensions Ila are connected by vertical memhers I! thus forming a chamber outside of the normal confines oi the derrick for receiving the upper ends otpipe racked within the derrick.

Fig. .3 illustrates a suitable detail for making the connections as described above; Auxiliary go generally vertical members I! are shown attached to the ends of extensions a, while the ends of the cross-bracing its connect with the points of intersection of the girts Ila and'member II.

The amount 0! added room aflorded within the g5 derrick depends upon the length or the exten-, sions its. In general it is -!easible to increase the room for racking pipe by from to 50%, without the necessity oi. increasing the strength of the gil'tl H. Generally it is desirable that the increased operating space he aflorded for a distance extending somewhat above the operating platform ll. At this point the oiiset may terminate abruptly. or it may taper back into the outline of the derrick, as illustrated in Fig. 1. 5 -Iig'.'2illustratesticallya racking. fingerboard ",usedinthe'racking of pipe. The center 01 the well hole is at II. which also is coincident with the center line of the derrick about which the upright structural members i8. 40 H, 'II and I! are symmetrically disposed. The

spacetutherightoftheiingerboard ilisavail able for racking pipe. With a conventional derrickthisspacewillbelimitedtothedistance between the finger board and the plane oI-the as structural members II and I3. However, with the present invention this space is new extended ct thegirts llaand the cross-bracing One feature oi my invention is that the disso sameas otthcgiris'ilaandcrom-bracing liatothegg a,1or,esa v metrically about a vertical central axis. and asends of the giitextensions -Ila, does not weaken the structure or alter the distributionof stresses to any material degree. The only change insofar as distribution of stresses is-concer'ned is that 'the stresses applied to girts li and [in are transmitted first through the girt extensions a. For reasons just explained 'all of the vertical stress components which would otherwise be received by the vertical structural members l0, ii,

I! and I 3, are still transmitted and received by these members, without material change in magnitude or direction. Therefore the utilization of the present invention in the building of a derrick does not involve undue expense, and dew not increase the cost to any marked degree.

It will be evident than-i! desired, girt extensio'ns may be provided upon two opposite sides of the derrick, and the girts and cross-bracing upon both sides attached to the girt extensions. However, for the majority of operating conditions-it is deemed that added room afiforded of the derrick, will suillce.

I claim:

- 1. In a derrick construction for oil and gas wells, four upright structural members symmetrically disposed about a vertical central ans, said members serving to carry substantially all of the downward force components of the derrick in compression, auxiliary generally vertical struc-= tural members on one side of said derrick spaced laterally from a pair of, said upright structural members for a substanital portion of the height of the derrick, means connecting said aumliary structural members with said pair of upright structural members, and cross-bracing connecting said aum'liary structural members to provide cross-bracing offset laterallydrom said pair of 1 upright structural members, there being no crossbracing between said pair of upright structural members through substantially the height occupied by said auxiliarystructural members, where by added working space is 'afiorded within the derrick between said pair of upright structural members.

2. In a derrick construction for oil or gas wells,

four upright structural members etrically disposed. about a vertical central ams, said mem= bers serving to carry substantially all of the downward force components of the derrlckin compression, cross-bracing serving to connect said members to form a. rigid structure, and means arrangedand constructed so that the cross= bracing on at least, one side of the derrick is 0&- set laterally from a pair of said upright structural members over a substantial portion of the height of the derrick, to afiord additional spacewithin the derrick for racking pipe.

3. In a derrick construction for oil or gas wells, four upright structuralmembers symmetrically disposed about a vertical central axis and carrying substantially all of the. downwardly directed force components of the derrick in compression, and cross-bracing serving to connect saidrnem bersto form a rigid structure, said cross-bracing including girts extending laterally beyond a pair of said upright structural members on at least one side of said derick. for a substantial part of its height, the cross-bracing on saidside being connected-with said pair of structural members by said extended girts, whereby the cross bracing onsaid side is offset laterally relatively to said pair of structural members .to afford added space within the derrick for racking pipe.

4. In a derrick constructionfor oil .or gas wells,

four upright structural members disposed sym= on one side sumlng substantially all of the downward force components of the derrick in compression, a plurality or horizontal girts attached to said structural members at two opposite sides of thederrick, vcertain of said girts having extensionsbeyond the adjacent structural members at a third.

side of the derrick, cross-bracing connecting cerfour upright structural members symmetrically disposed about a vertical central axis, said members assuming substantially all offthe downward 1 force components of the derrick, a plurality of horizontal girts directly connected to and extending between said members on three sides of the derrick, the girts on two sides of the derrick being extended on the, fourth side of the derrick beyond the line of the adjacent structural members defining said fourth side, cross-bracing on said three sides of the derrick, said cross-bracing being-substantially in planes coincident with the line of centers of adjacent structural members,

and cross=bracing on said fourth side of the derrick beyond said line oi said adjacent structural members and between the ends of said extended girts, whereby added worming space is afforded within the derrick. v

6. In a derrick construction for oil or gas wells, four upright structural adapted to assuhstantially all of the downward forcev components of the derrickln coression, a plurality of girts attached to said structural memand extending between said structural membars on three sides of the derrick, certain of said girts having extensions on the fourth side of the derrick, auxiliary generally vertical structural members connect the ends of the extensions, cross-bracing on said three sides of the derrick, said cross-hr being dis -i in planes substantially coincident'with theline of centers or adjacent upright structural members,

and cross=bracing upon the fourth side of thederiiick extending between said aumliary structural members whereby added wormng'space is aiiorded within the derrick for racking of pipe,

and whereby said cross-bracing upon the fourth side of the derrick strengthens the derrick'substantially the same as it said cross-bracing were directly applied to the adjacent upright structural members.

7. In aderrick of the type described, the com= bination of: a base; and a derrick structure ex tending upward from said base, said derrick structure having corner members-secured together by sets of connecting members lying in the planes defined by adjacent corner members, one of said combination of: corner members extending in upright and spaced relation so as to define a derrick space; sets of connecting members arranged in consecutive order and connecting adjacent corner members together; and means to space at sets of connecting members being spaced outward- 'ly from the plane 01 the comer members which least one of said sets of connecting members out-;

'wardly from the plane defined by two adjacent corner'mbers, so asto provide a space lying exterior of the derrick and in communication with the interior base of the derrick, to receive the upper end 01' a pipe standing on a floor at the lower end of the derrick.

9. In a derrick of the character described, the

combination of: a base; and a derrick structure on saidlbase comprising a plurality of bays ar-- ranged in vertical order, at least one of said bays in the upper portion of the derrick structure be ing laterally enlarged at a side thereof so as to form a chamber which communicates with the in terior oi the derrick and projects laterally therefrom so as to provide a space lying outsidejthe 10. In a derrick of the type described, the combination of a base; and a derrick structure extending upward from saidbase, said derrick 6 structure being formed of a structural part defining side planes for the derrick, there being structural parts secured to the upper part oi the derrick so as to lie outside one of said side planes and form a pipe-head chamber communicating 10 with the interior of the derrick structure.

LESLIE A. RAWSON,

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