US2500276A

US2500276A - Safety joint

Info

Publication number: US2500276A
Application number: US636898A
Authority: US
Inventors: Walter L Church
Original assignee: Individual
Current assignee: Individual
Priority date: 1945-12-22
Filing date: 1945-12-22
Publication date: 1950-03-14
Anticipated expiration: 1967-03-14

Description

March 14, 1950 w, CHURCH 2,500,276

SAFETY JOINT Filed Dec. 22, 1945 I i .2 I

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Patented Mar. 14, 1950 UNITED STATES FATENT OFFICE SAFETY JOINT Walter L. Church, Houston, Tex.

Application December 22, 1945, Serial No. 636,898

1 Claim. 1

This invention relates to a safety joint.

An object. of the invention is to provide a safety joint which is specially adapted for connecting sections of an operating spring of pipe and which may be readily broken and separated in case it becomes necessary to do so.

The type of joint herein described has been specially designed for use in connecting string of pipe to a packer to be set in a well.

In the production of oil, or other fluids, from a well it is not. uncommon to set a packer in the well and to produce the fluid through the string of pipe by means or which the packer is set. It sometimes becomes desirable to collapse and remove the packer and the setting string of pipe from the well but in case the packer cannot be removed it is desirable to detach and remove the string of pipe.

In order that the string may be detached the safety joint hereindescribed is incorporated into the string above the packer so that when it is attempted to detach the string from the packer the safety joint will, break, and can be unscrewed, more easily than the couplings connecting the sections of they string above. This will in,- sure the ready removal of the entire operating string from the well in case the packer becomes stuck and cannot be removed.

It is another object of the invention to provide a safety joint of the character described that will not readily part, or unscrew, while the packer is being lowered into the well or during the manipulation of the string during the setting operation but which may be readily unscrewed and detached from the packer mechaanism beneath in case the packer becomes sanded up or for any reason stuck in the well so that it cannot be removed.

With the above and other objects in view the invention has particular relation to certain novel features of construction, arrangement of parts and use, an example of which is given in this specification and illustrated in the accompanying drawings, wherein:

Figure 1 is a side elevation, partly in section, of the safety joint showing the coupling members connected together.

Figure 2 is a fragmentary side elevation of the pin member and means for coupling said member to the string of pipe above; and

Figure 3 is a cross-sectional view taken on the line 3-3 of Figure 1.

Referring now more particularly to the drawings wherein like numerals of reference designumeral i designates an operating string of pipe which extends to the ground surface.

Screwed onto the lower end of the string there is a tubular reducing bushing 2, threaded onto the lower end of which there is a tubular outer nipple 3.

The numeral i designates a tubular pin member whose upper end fits snugly in the lower end of the nipple 3 and whose lower end is reduced in diameter forming the downwardly facing, external annular shoulder 5, and extending upwardly from this shoulder on opposite, sides are the

longitudinal keyways

6, 6 which extend up the required distance. Above said keyways and countersunk into the enlarged upper end of the pin member are the annular seals '1, l which extend around said pin member and form seals with the nipple .i.

The lower end of the nipple is formed with the inwardly extending keys 8, '8. which extend into said keyways.

There is a tubular box member S3 which is provided with internal coarse threads [0 and said box member is internally blank above and beneath said threads.

The reduced portion of the pin member is provided with coarse external threads I! adapted to mesh with the threads it when the pin member is screwed home into the box member.

The pin member is externally blank above and beneath the threads H, said blank portions fitting into the blank portions of the box member when said coupling members are screwed together.

Countersunk into the pin member beneath its threads are the annular seal rings [2 which form seals with the box member when the pin member is screwed home therein. The threads Hi and H, in the present illustration, are left hand threads.

The box member has the slots, as l3, which are formed in the end of the box member which is adjacent the nipple 3. These slots have the laterally turned notches, as l3a, at their lower nate the same parts in each of the figures, the

ends, said notches, in the present illustration, being turned to the left and thus forming overhanging shoulders, as M, and the adjacent end of the nipple 3 is provided with the extended prongs l5, 15 which extend into the slots l3 but which are somewhat narrower than said slots, as shown in Figure 1, and which have lateral projections Isa extended into the notches l3a and forming the shoulders 16 arranged to interlock with the shoulders I 4. These shoulders are maintained in interlocking relation by means of a key l1? 3 which is shearable under abnormal, torsional strain.

In assembly the pin member 4 is screwed into the box member 9 to home position and the prongs l5 are then moved into the slots l3 and turned to interengage the shoulders It with shoulders M and the key ll is then countersunk into the adjacent ends of the nipple and box member, as shown in Figure 1. The nipple 3 is then screwed onto the reducing bushing 2 which is attached to the operating string of pipe I.

A well packer assembly may then be connected onto the threaded lower end [8 of the box member 9 and the packer mechanism let down into the [well bore to the desired location.

In order to set a type of packer assembly with which the safety joint is designed to be used the operating string must be turned to the right so as to release the packer assembly and allow it -to become engaged with the well casing and the operating string is then lowered to subject the packer to the weight of the operating string to expand the packer.

The key ii is of sumcient strength to withstand the torsional strain of this operation so that the safety joint will not be liable to become separated.

Later if it should be desired to remove the packer from the well an upward pull may be taken on the operating string and the shoulders l6, l4 being engaged the load will be assumed by them and the packer assembly may be removed from the well.

However, if the packer assembly is sanded up or stuck so that it cannot be removed by a straight pull the operating string of pipe may be turned to the right and the pin H sheared and the shoulders I S will then become disengaged from the shoulders l4 and upon an upward pull on the string of pipe the nipple 3 will move upwardly relative to the pin member 4 until the keys 8 engage the upper ends of the keyways B and the operating string may then be turned to the right and the threads ll disengaged from the threads l0 and the operating string may then be withdrawn from the well bore and thus recovered.

The drawings and description are illustrative merely while the broad principle of the invention will be defined by the appended claim.

What I claim is:

A safety joint for connecting sections of a string of pipe and comprising, a tubular nipple, a tubular pin member, one end of which is telescoped into and has a slidable splined connection with the nipple and whose other end is provided with external threads, a box member having internal threads into which said other end of the pin member is threaded, the end of the box member, adjacent the nipple, being formed with a slot having a laterally turned notch at its inner end, thus forming an overhanging shoulder and the adjacent end of the nipple being provided with an extended prong which extends into said slot and is narrower than the slot, a lateral projection on said prong which extends into said notch and which forms a shoulder, said shoulders being arranged to interlock to hold the adjacent ends of the nipple and box member in contact, frangible means initially locking the nipple and box member together against relative rotative movement when the projection extends into said notch, but which is shearable, under stress, to allow disengagement of said shoulders to permit relative longitudinal movement of the nipple and box member, and means arranged to prevent complete separation of the nipple and box member.

WALTER L. CHURCH.

REFERENCES CITED The following references are of record in the file of this patent.

UNITED STATES PATENTS Number Name Date 2,049,290 Burns et a1 July 28, 1936 2,113,821 Baash Apr. 12, 1938 2,189,697 Baker Feb. 6, 1940