US2875983A - Jar bumper sub - Google Patents

Description

W. N. SUTLIFF JAR BUMPER SUB Filed March 25, 1957 Mmh 3, 1959 United States Patent 0 JAR BUMPER SUB Wayne N. Sutlilf, Bakersfield, Calif.

Application March 25, 1957, Serial No. 648,138

2 Claims. (Cl. Z55- 27) n This invention relates to 'jar bumper subs and more partlcularly to a novel jar'bumper sub having a'snap action.

Jar bumper subs are in common use in deep wells to ternal snap bead 25 having an upper bevel 26 and a lower Internal tube 12 has a cylindrical external surface-30v A which slidably fits bore 15. Extending radially from a Inasmuch as it is frequently desirable or necessary to perform auxiliary operations requiring apparatus of substantial size to be lowered through a jar bumper sub while the latter is in a well, the internal diameter of the sub is preferably made as large as is compatible with giving the' required strength to this tool. A tool with an outside diameter of six inches thus requires for such operations an internal diameter of two inches.

Another object of the present invention is to provide a snap action jar bumper sub in which the desired ratio of one to three between the internal and external diameters of the sub is not disturbed by the snapA action feature.

The manner in which the foregoing objects are attained as well as further objects and advantages will be made manifest in the following description taken in connection with the accompanying drawings in which Fig. 1 is a diagrammatic vertical sectional view of a preferred embodiment of the snap action jar bumper sub of the invention, with the slip jaws thereof engaging the snap bead from beneath in preparation for strikingl an upward blow.

Fig. 2 is a view similar to Fig. 1 with the hammer splines contacting the upper anvil as when striking an upward blow.

Fig. 3 is an enlarged cross sectional view taken on the line 3--3 in Fig. 2, and showing the construction of the slip clutch jaws of the invention.

' Fig. 4 is an enlarged cross sectional view taken on the line 4-4 of Fig. 2 and `shows the splined connection between the inner and outer tubes of the invention.

Referring specifically to the drawings, the invention is there shown as embodied in a jar bumper sub 10 which includes an external tube 11 and an internal tube 12, which are telescopically related.

External tube 11 has an internally splined main body section 13 and a thin walled neck section 14 which sections have a common bore 15. Spline channels 16 areformed in the bore 15 in section 13, upper ends of these channels forming shoulders comprising upper anvils 17.

Splined body section 13 terminates at its lower end in an internally threaded section 18 into which a tubular joint 19 screws, this joint serving to form a lower anvil 20 and connect external tube 11 with the upper end of a fishing tool or other drill string element 21 therebeneath.

The neck section 14 extends upward from section 13 and is provided nearits upper end with an annular exlower portion of internal tube 12 are hammer splines 31 which slidably iit within spline channels 16.

Tube -12 has a bore 32 the diameter of which is approximately one third the external diameter of external tube 11.

The upper end of tube 12 is externally threaded and screws into an upper joint section 33 by which the sub.

10 is connected with the lower end of a drill string 34.

- Joint section 33 is provided with a circumferential series of -spring slip clutch arms 40 having inturned jaws 41 with upper and lower bevelled faces 42 and 43 respectively.

Operation The snap action mechanismv of jar bumper sub 10 may be utilized to introduce a snap action into theV delivery of a blow from hammer splines 31 onto either the upper anvil shoulders 17 or the lower anvil 20. Figs. l and 2 show two steps in the delivery of an upward blow.

Such a blow is accomplished by slowly lifting the drill string 34 until the jaws 41'rest with their upper bevelled faces 42 meeting face to face with the lower bevelled faces 27 of the snap bead 25 as shown in Fig. l.

Assuming the element 21 is stuck in the wall, this en gagement of the bead l25 with jaws 41 will arrest the upward movement of the jaws and cause stretching of the drill string 34 to result from further lifting its upper end at the top of the well. When the upward pull thus applied by the lower end of drill string 34 to jaws 41 produces outward radial resultants which simultaneously exceed the opposing frictional forces and the spring action of arms 40, the latter will expand suddenly to allow jaws 41 to slide over bead 25 causing the internal tube 12 t0 be snapped upwardly with hammer splines 31 striking anvil shoulders 17 a relatively high velocity blow, as shown in Fig. 2.

It is to be noted that jaws 41 are now disposed above snap bead 25 with lower bevelled faces 43 thereof opposed to upper bevelled faces 26 of said bead. The jar bumper sub 10 is now in readiness to effect a downward snap action blow of spline hammers 31 against anvil 20.

This is accomplished by a procedure practically the reverse of that just described. The upper end of drill string 34 is lowered, gradually increasing the downward pressure of the jaws 41 on the annular bead 25 until these finally snap outwardly and over said bead permitting the accumulated expansive resilience of the drill string to snap the internal tube 12 downwardly striking hammer splines 31 against the anvil 20 with a high velocity blow. The O-ring 29 produces a substantially liquid tight seal between internal tube 12 and external tube 11 so that jar bumper sub 10 constitutes a fluid tight link at all times between drill string 34 and element 21 which is suspended from the jar bumper sub.

It is to be noted that the snap action mechanism of sub 10 is externally arranged so as to permit internal tube 12 to be relatively thick-walled and also allow external tube 11 to be heavily constructed in the lower section 13 thereof which interlocks with internal tube 12, and at the same time permit bore 32 of the internal tube 12 to be approximately one third the outside diameter of the sub 10.

The present invention is thus seen to combine the snap action feature with a jar bumper sub without any sacritice of a commodious internal passage through the sub 0r that ruggedness essential in its structure.

. `Patented Mar. 3, 195.9

genoss While only a single embodiment of the invention is illustrated herein, it is to be understoody that various modications may be made in this without departing from the spirit of theinvention or thescope of the appended claims* The claims are:

v 1. A well tool comprising inner and outer telescopically related tubular elements,` means for connecting one of said elements to a drill string, means for connecting the other element to an object to be jarred, overlapping portions of saidl elements providing an annular hammer chamber, an annular'v shoulder extending radially inwardly from said outer element, said shoulder forming a bearing through-'which said inner element is axially slidable and closing one end of said chamber, there being radial impact faces provided on saidouter element at opposite ends of` said hammer chamber, a hammer provided to extend radially outwardly from said inner element into said4 chamber, said hammer having free axial movement Within ysaid chamber terminating in engagement of said hammer with one or the other of said impact faces, and spring detent means for resisting relative axialy movement between said elements, said means being located between said shoulder on said outer element and the connection means associated withU said inner element, said spring detent means including a circumferentially arranged series Q f axially extending spring arms provided on one of said 4 l elements at one end of said series and having inturned inwardly biased jaws at the opposite free'ends of said arms, said spring detent means alsoy including annular snap bead means provided on the other tubular element and being opposed to said jaws thereby requiring the latter to snap outwardly and pass over said bead means for said hammer to move axially through said chamber into contact with one of said impact faces.

2. A combination as in claim l in which said series of spring arms is provided on said inner tubular element at the end thereof associated with one of said connection means, and a thin sleeve provided on said shoulder of said outer element and forming a continuation of the bearing provided by said shoulder for said inner tubular element, said sleeve extending towards said arms and having 4mounted thereon said annular snap bead with the latter in operative relation with said jaws as aforesaid.

References Cited in the tile of this patent UNITED STATES PATENTS

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