US2241274A - Safety device - Google Patents

Description

May 6, 1941. G. A. SEVERSON SAFETY DEVICE Filed Sept. 27, 1938 GEORGE A;$EVER$ON INVENTOR ATTORNEYS Patented May 6, 1941 George A. Severson, Tulsa, Okla., assignor to The Texas Company, New York, N. Y., a corporation of Delaware Application September 27, 1938, Serial No. 231,871

2 Claims.

This invention relates to safety devices and more particularly to a device for automatically applying a brake to the draw-works of a well being drilled and also disconnecting the power or drivingmechani'sm from the draw-works in case of an emergency such as the breakage of the drill pipe or tubing when being raised or lowered in the well.

The primary object of the invention is the pro vision of a device of this kind which vwill besimple of construction and which will be entirely automatic in its operation so that in case the "operator is not sufliciently quick at the time when the drill pipe should breakthe driving mechanism would be disconnected and the brakes applied before any damage can be done to the derrick or other equipment of the well. When drilling a well and more specifically while pulling the drill pipe upwardly, there have been instances when, either because of the sudden breaking of the drill pipe or for other reasons, a sudden release of weight has caused the pulley from which the pipe is suspended to overtravel in an upward direction, thereby striking the crown block or other parts of the derrick with attendant damage thereto. In accordance with this invention, a tripping lever is provided in the path of the pulley, this lever being connected by means of a cableto a device disposed near the drawworks and arranged so that in the event the lever should be struck by the pulley the consequent movement of the lever will cause the tripping device to release a spring to apply the brake to the draw-works while at the same time releasingthe clutch between the draw-works and the 4 steam engine or electric motor. A clutch 34 is ar ranged in the drive shaft 36 and is adapted to be engaged or disengaged manually by means of the hand lever 38 and yoke 40 mounted on the shaft I bands being connected to lugs 46 secured to a shaft 48 on which shaft is also mounted a hand lever 50. The operator by pulling the lever 50 to the left can apply more or less braking force to the winch ,2 8 and can thus control the speed of the pulley 20 and the drill pipe suspended therefrom. When the drill pipe is'being raised the operator, by means of the lever 38, will of course disengage the clutch 34 when the pulley has reached a suflicient height so that a section of the drill pipe can be unscrewed and removed. The pulley 20 will then be lowered and attached to the end of the next section of drill pipe slightly above the rotary table H and the raising operation will be repeated. When running the drill pipe into the hole the operator can control the lowering speed in a similar manner by means of the brakes 44 on the winch 28.

As stated hereinbefore, there have been instances when, usually because of the breaking of the string of drill pipe, the pulley has overtraveled in an upward direction due to the sudden release of weight carried thereby. Unless the operator is quick enough to disengage the clutch 34 and to apply the brake H, the pulley 20 will strike the crown block I 8 and this may result in considerable damage to the block and other equipment.

- driving engine. The upward movement of the pulley will thus be stopped due to the braking action on the 'draw-workswhile the brakes will not be damagedbecause of the simultaneous disconnecting of the power clutch.

For a -further description of the invention, reference may be had to the accompanying drawinginwhlch I f" Figure '1- is a somewhat diagrammatic representation of the device as applied to the drawworks 'of'a well or bore hole being drilled, and

Figure 2 is a longitudinal elevation of a sec? tion of the tripping mechanism.

" Referring to the'drawlng; a derrick in is shown which may be, for instance, a combustion engine,

'tically as mounted on a' platform, 12,

by means. of thelcable 22 and thesmall pulleys, 24. y

Breakage of the cable 2 may also result.

In order to prevent this overtravel of the pulley incase of an accident, the following device is provided. A lever 52 is pivoted at its end 54 tothe derrick or some other support and its other end has attached thereto one end of a cable 55. The lever 52 is arrangedin the path of the pulley 20 at a point below the crown block I l and above the highest point reached by the pulley in normal operation of the draw-works. In case of breakage of the drill pipe the pulley 20 in overtraveling in an upward direction will strike the lever 52 thus pushing it upward and giving an upward pull to the cable 56. The cable 56 passes around asuitable pulley 58' and has its other end attached to. one end of a tripping lever 82, the purpose of which will be described hereinafter.

As shown more clearly in Figure 2, a collar 64 is rigidly secured as by means of the pin 65 to the shaft 48 at the right hand end ot which are mounted the lugs 45 attached to the brake bands 44; The hand lever 50 is provided wlth'asleeve 68 mounted so as to be rotatable and slidable on ,the shaft 48 and the sleeve is provlded wlth a tooth or projection 10 adapted to engage a similar tooth 12 on the collar 64. It will thus be seen that in the position shown in Figure 2, when the lever 50 is grasped by the operator and pulled downwardly toward him, the collar 64 and the shaft 48 will be rotated in a sense to apply the brakes 44.

Also secured to the shaft 48 and spaced from the collar 64 is another collar 14 provided with av end to a suitable boss 88 on the sleeve 80 while its other end 90 is adapted to engage the platform l2 or some other support. The spring 86 is so wound that with the parts in the position shown in Figure 2, the spring will turn the shaft 48 so as to apply the brakes 44. A second boss 92 projects from the sleeve 80 and is adapted to be engaged by a finger 94 on the lower e d of the tripping lever 62. The lever 62 is pvoted near its midpoint to a support 96.

As before stated, in normal operation the operator by grasping levers 38 and 50 will control the engagement of the drive clutch and also the brakes 44. In the event of breakage of the drill pipe string and in case the operator is not quick enough to disengage the clutch and apply the brake, the pulley 20 in striking the lever 52 will raise the same, thus pulling on the cable 56 and swinging the tripping lever 62 so as to disengage the finger 94 from the boss 92 on the collar 80. The spring 86 will thereupon rotate the sleeve 80 so that the projection 82 will engage the projection 84 on the collar 14 to thereby rotate the shaft 48 and apply the brakes 44. At the same time the clutch 34 will be disengaged in a man-- her to be described hereinafter and the pulley 20 will thus be brought to a stop before it strikes the crown block l6.

After the brakes have been applied in this manner through the release of the tripping lever 62, it will be necessary to rewind the spring 86 and to reset the lever 62. To this end the operator will slide the lever 50 and its sleeve 68 to the left along the shaft 48 so that the tooth I8 will engage the tooth 16 on the collar 14. He will then move the lever 50 in an upward direction. i. e., in a. direction away from him, and the collar 14 will turn the sleeve 80 until the boss 92 will engage the finger 94 on the tripping lever. The

device will then be in readiness for further automatic operation as has been described and the lever 60 will be shifted back to the position shown in Figure 2 so that the operator can control the brakes manually.

A similar arrangement has been provided for '"automatically disengaging the clutch 84 at the j same time that the brakes 44 are applied by the spring 66. The shaft 42 is supported in bearings on the derrick platform l2 at right angles to the drive shaft, 36 andthe yoke 48 connected to theclutch"3 4- and at its other end is fixedly se- Poured tothe shaft 42. Theha nd lever 38 which similar in all respects to the brake lever 60 i to the elements 1.0 and 1-2; shownin ,Lby grasping the :rotatably and slidabiygmounted onthe if h etharight can dis- 6 engage the clutch 34 at will. The shaft 42 also has mounted thereon elements corresponding exactly to the spring 86, sleeve 80, collar I4 and their projections and bosses, as shown in Figure 2, and a tripping lever 98 is mounted so as to hold the spring in its wound position in the same manner as has been already described with regard to the lever 62. A branch cable I00 is secured at one end to the cable 56 and at the other end to the tripping lever 98.

The operation of the clutch tripping mechanism is the same as that of the automatic brake applying mechanism and it will be seen therefore that when the pulley 20 strikes the lever 52, thus pulling the cable 56, the brakes 44 will be applied to stop the rotation of the winch 28 and simultaneously therewith the clutch 34 will be disconnected. The driving engine or motor 82 will thus not need to be stopped and there will be no undue wear ,of the .brake bands 44 after the. clutch has been disengaged. In case the clutch should be automatically disengaged in the manner described, the spring I02 can be subsequently rewound in the same way as the spring 86 of the brake-applying mechanism.

Obviously many modifications and variations of the invention may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated by the appended claims.

I claim:

1. In a well drilling apparatus, a derrick, a draw-works having a winch, an engine, a driving connection between said engine and said drawworks, a clutch in said connection, a pulley suspended in said derrick, a cable connecting said winch and pulley so that as said draw-works is operated the pulley will be raised or lowered in the derrick, means for braking said draw-works, means for automatically disconnecting said engine from and applying said braking means to said draw-works in an emergency, comprising manual operating mechanisms for said clutch and said braking means, resilient means connected to said operating mechanisms so as to bias said mechanisms toward clutch-disengaging and brake-applying positions, trip means for normally holding said resilient means in inoperative position and means for actuating said trip means to render said resilient means operative comprising an arm pivotally mounted in the path of upward movement of said pulley and means I connecting said am with said trip means.

2. In a well drilling apparatus, a derrick, a

gine, a brake associated with said winch, means for simultaneously forcing said brake to its applied position and said clutch into its disengaged said forcing means in an simultaneously,

position, releasable means. for normally holding inoperative position, a derrick in the path of pulley and a connectrip lever mounted in said upwardv movement of said tion between said lever and said releasable means soQthatLon-a predetermined upward movement said pulley -wil1 strike said lever to actuate said releasaiiiehieans wherebyi said clutchwm' b s;

engaged and said brake applied to said winch GEORGE a sEvERsoN.

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