US2153816A - Sucker rod jerk absorber - Google Patents

Description

B. H. STEVENS SUCKER ROD JERK ABSORBER Inventor Filed Nov. 30, 1937 Attorneys April 11, 1939.

Patented Apr. 11, 1939 UNITED STATES PATENT oFFlcE 1 Claim.

jerk to which the sucker rod is subjected during the well-pumping motion or operation.

In accordance with the present invention, a device is provided which is designed for interposition between two sections of a sucker rod for the purpose of relieving the rod of undue vibration, torsional strain, twist and jerk; and the invention together with its objects and advantages will be best understood from a study of the following description taken in connection with the accompanying drawing wherein:

Figure 1 is a longitudinal sectional view through the device with certain parts shown in elevation,

Figure 2 is a transverse sectional view taken substantially on the line 2-2 of Figure 1, and

Figure 3 is a perspective View of a piston.

Referring to the drawing by reference numerals it will be seen that the absorber comprisesran elongated cylinder or barrel 5 into the upper end of which is threaded a cylindrical plug 6, and into the lower end of which is threaded a cylindrical plug or coupling element 'I.

The plug or element 'I is provided in the free end thereof with a threaded socket 8 for receiving the threaded end of a sucker rod section.

The plug 6 is longitudinally bored and is also suitably formed to provide a packing box 9 in which is seated a suitable packing Il) and a gland II, packing Il) and gland II accommodating a piston rod I2 as shown.

The rod I2 at one end thereof is suitably provided in a manner (not shown) to attach said' end of the rod to one end of a second sucker rod section whereby the absorber may be interposed between the said sections of the sucker rod.

On the inner end of the piston rod I2 there is provided an elongated piston I3, one end of which bears against a washer I 4 held on the rod I2 between the lower end of the piston I3 and a nut I5 threaded on the lower or inner end of the rod I2 as shown in Figure 1.

Fitting snugly within the barrel 5 above the piston I3 is a cylindrical air chamber I6 formed of metal or other suitable material of hollow shell-like form and provided in its lower end with a circular series of air ports I'I.

Between the chamber I6 and the piston I3 there is within the barrel 5 a suitable hydraulic fluid, I8, such as oil or the like.

Further the piston I3 ls suitably secured on the inner end of the rod I2 through the medium of a conical wedge I9 which fits snugly within a conical bore 20 provided therefor in the piston I3, and at the base of the cone the wedge I9 abuts a shoulder 2l provided on the rod I2 as shown.

The operation, utility and advantages of a device of this character will be apparent from the following:

The pumping action causes an upward pull on the piston rod I2 which, through piston I3, exerts pressure on the hydraulic fluid I 8. '1211s in turn results in pressure being exerted. on the air chamber I6 through the ports I'I so that the upward movement of the rod I2 is transmitted to the lower section of the sucker rod for causing the latter to move upwardly with the rod string. Manifestly by providing the air chamber I5 and the fluid IB within the barrel 5 above the piston I3 a cushion eifect is obtained with the result that no jerk or snap is imparted to the sucker rod string during the pumping operation.

On the downstroke of the sucker rod string the pressure exerted on the air chamber I5 together with the partial vacuum created on the hydraulic fluid I8 by the downward motion of the piston rod I2 and piston I3 causes the parts to return to their normal position.

It will thus be seen that I have provided a device which may be readily inserted between two sections of a sucker rod string and which device if so used will serve to absorb the shock or jerk to which the rod sections are ordinarily subjected during the pumping operation.

It is thought that a clear understanding of the construction, utility and advantages of an invention of this character will be had Without a more detailed description.

Having thus describedthe invention what is claimed as new is:

A cushioning device for a sucker rod string comprising a barrel containing fluid, a coupling member closing the lower end of the barrel, a plug closing the upper end of the barrel, a piston rod passing through the plug, packing means in the plug through which the rod passes, a piston in the barrel connected with the lower end of the rod, an air chamber in the upper part of the barrel below the plug including a cylinder having a working fit with the barrel, a tubular member in the cylinder and having a working fit on the rod, and end pieces connected with the tu bular member and the cylinder and forming an air chamber between the tubular member and the cylinder, the lower end piece having perforations therein for adjoining the interior of the air chamber with the interior of the barrel.

BEN HARWOOD STEVENS.

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