US985197A - Well-casing spear. - Google Patents

Description

J. B. NORRIS. WELL UASING SPEAK,

APPLICATION FILED JULY 1, 1910.

985,197. Patented Feb.28, 1911.

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JOSEPH B. NORRIS, OF CORSICANA, TEXAS.

WELL-CASING SPEAR.

quently occurs that a section of a well (7515- ing must be withdrawn either because of its breakage or for other reasons. In order to remove the damaged casing section, a clamping device known as a casing spear is lowered into the well, and after the casing spear has been introduced into the section of casing to be removed, an upward tension upon the casing spear causes it to clamp upon the casing so that the two may be simultaneously withdrawn from the well. In some cases, however, the section which it is desired to remove is so securely positioned in the well that it cannot be removed by this means. It then becomes desirable to detach the casing spear from the section in order that the former may be withdrawn from the well.

It is therefore the object of the present invention to provide a casing spear which may be made to clamp automatically upon a section of well casing, and which also may be automatically released from the casing if desired without the necessity of lowering any further apparatus into the well to accomplish this result.

A further object 01' the invention is to provide a device for this service that will be strong, durable, simple and efficient and comparatively easy to construct, and also one which will not be likely to get out of working order.

lVith these and various other objects in view myinvention has relation to certain novel features of construction and operation, an example of which is described in the following specification and illustrated in the accompanying drawing, wherein;

Figure 1 is a vertical sectlonal view through the axis of a section of pipe casing showing the herein-described well casing spear positioned therein, the position shown being that assumed by the parts of the device when it is first introduced into a section of casin Fig. 2 is a similar sectional Specification of Letters Patent.

Application filed July 1, 1910.

Patented Feb. 28, 1911.

Serial No. 569,896.

view in which the well spear has been introduced into a casing and has been subjected to an upward tension causing the device to clamp against the walls of the easing. Fig. 3 is a similar View illustrating the position assumed by the parts of the spear when the effort to raise the pipe easing has been abandoned and the spear has been lowered in order to release the clamping means. Fig. t is a cross section through Fig. 2 taken on the line aa2.

Referring now more particularly to the drawing wherein like letters of reference designate similar parts in all the figures, the letter A designates the section of well casing which it is desired to remove from the well.

The letter B designates an upwardly tapering mandrel which forms the main body of the casing spear. The upper extremity of this mandrel is threaded to receive a section of pipe C, a plurality of which sections are connected together in order to lower the mandrel into the well. Upon the mandrel B is mounted a serrated split collar the teeth of which are arranged in annular horizontal rings with their sharp edges upwardly di rected. The inner wall of this collar is tapered to fit the mandrel, the diameter of theape'rture being such that the collar fits tightly upon the mandrel at its middle portion. In the middle portion of the mandrel at oppositesides thereof dogs E are pivotally mounted upon pins F. These dogs are each in a slot G in the wall of the mandrel, and each dog is provided with a slotted aperture H to receive the pin F adapting the dog to move laterally upon its supporting pin. The top and bottom surfaces of these dogs incline inwardly toward each other, and

at the junction of these surfaces each dog is acted upon-by a spring K. The two springs K are carried by a split collar L which is mounted within the tubular interior wall of the mandrel. and is restricted from vertical displacement by a pin M. A spline N prevents rotation of the collar D upon the mandrel without. interfering with its longitudinal motion thereupon.

hen the casing spear is first introduced into a section of easing the dogs occupy the position illustrated in Fig. 1. The collar D occupies its highest possible position relative to the mandrel B since friction between the collar and the well casing retards the collar as the mandrel moves down. When means, the mandrel is again lowered into :l}l1 e,. p0S 1lZ-1O11 illustrated 1n Flg. 3, the dogs .throughthe action of the springs K and asan upward pressure is exerted upon the mandrel through the pipe section's C, the

mandrel moves upward for a short period without affecting the collar D, but when the mandrel reaches the position shown in Fig. 2 during its upward motion, it tightens upon the collar D and springs said collar. outwardly forcing the teeth ofthe latter into the wall of thecasing. At the same timethe dogs E are displaced inwardlyloy the collar JD ,assu1ning.-tl1e position shown in .Fig. 2;

I-nthis position, the casing spear grips the pasing morefirmly as the amount of upward tension isincreased. If it be foundthat the casingsection cannotbe withdrawn by this B being released or displaced outwardly suming the position illustrated in Fig. 3 with tlieirupper edges pro ect1ng.- When anupward.pressureis now exerted uponthe mandrel the dogs E will .s'upportthe lower .edge ofthevcollar 1D and prevent said collar. tightenlng upon the ananclrel. The casing spear therefore may be removed since the collar D will no longer act as a' clamp.

.It isolovious that thespring K may be i given other forms than that illustrated withtion.

ontdeparting from the spirit of the inven- Wfanous other changes may be made in theydetails of thedevice without sacriii cingits advantages or departing from the spirit of the invention.

\Vhat Iclaim is: a

1. In a casing spear, the combination with an upwardly tapering mandrel f a split collar mounted thereupon having a serrated outer surface, and having its inner surface tapered to conform with the mandrel, a dog 'pivotally-mounted in the wall of-the mandrel adapted to be pressed inward by said collarwhen the latter tightens upon the mandrel, and a spring acting. upon said dog adapted toforce its upper corner outwardly of the mandrel. provided with a transversely V slotted aperture receiving the pivot, and a sprlng acting on said dog causing thclower portion of the dog to pro ect fronrthe mandrel normally, and the upper edge thereof to project after the dog has been subjected to apartial rotation by beingpressed.inward by the aforesaid collar.

*In testimony whereof I have signed my name to .this specification inthe presence of two subscribing witnesses.

JOSEPH B. NORRlS.

Witnesses:

WV. M. Insulin, F. M. RUNDELL.

iG opies of this patent may be obtained for five cents eaclntby addressing the Commissioner of Patents,

- Washington, D. C.

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