US1621665A - Crank for drilling rigs - Google Patents

Description

March 1927' E. E. GREVE 'CRANK FOR DRILLING RIGS Filed Aug. 17, 1922 ATTORNEY Patented Mar. 22, 1927.

I i,621,66a

QEFECE.

EDGAR E. GREVE, 0F BELLEVUE, PENNSYLVANIA.

CRANK FOR DRILLING RIGS.

Application filed August 17, 1922. Serial No. 582,527.

This invention relates to a crank construetion, particularly a construction "especially adapted for use in earth drilling rigs.

In oil well drilling rigs a shaft is rotated through a band wheel fixed to the shaft. This shaft as heretofore constructed, has a crank keyed thereto. This crank, through a pitman connection, is utilized in effecting an oscillation of the walking beam. Thus a great deal of vibration and jar is transmitted through the various fixed connections to the entire drilling rig and the tools are prevented from having a free drop in the hole by reason of the walking beam being rigidly coupled to the shaft which is driven from the engine through the band wheel.

The present invention has as a primary object the provision of a crank designed to allow the tools to have a free downward drop and which will eliminate much of the jar and vibration incident to the present arrangement now in general use.

The invention may be readily understood by reference to the accompanying drawings, in which:

Fig. 1 represents a side view of a walking beam connected with a drive shaft through a crank involving my invention.

Fig. 2 is a side view on a larger scale of the crank.

Fig. 3 is a top plan view.

Fig. 4 is a section on line IVIV of F1g. 2.

In the drawings 5 designates a bearing in which is a shaft 6 having a band wheel 7 keyed thereto. The shaft is adapted to be continuously rotated from an engine not shown, but in a manner well understood in the art. The end of the shaft projects beyond bearing 5 and fixed or keyed to this projecting end is a disk 8 which has an overhanging or projecting lug extending across a portion thereof. In the lug are pockets 9, in which are the heads of contact pins 10, the shanks of the pins projecting through the lug as shown. The pins are yieldably held with their shanks so projected by springs 11 held in the pockets by screw plugs 12. The lug may be counterbalanced on the disk by portion 13.

Loose on the projecting end of the shaft so as to be freely rotatable, and disposed. between disk 8 and washer 14 on the end of the shaft is a crank 15. Washer 14; is held in place by bolt 16. The crank has a radial arm 15 which is provided with one or more openings 17 through which the wrist pin 18 of the pitman connection may pass. The pitman, shown in Fig. 1, is designated 19 and the walking beam is designated 20.

In operation, assume the crank to be rotated in a clockwise direction, the lug projecting over the crank, as shown in Fig. 2. As long as the crank is moving through the part of its travel to draw the pitman 19 downward, during which time the walking beam is elevating the drilling tools, the lug will transmit motion to the crank. When, however, the crank is moved past dead cen 'ter on the downward limit of its movement, the weight of the drilling tools on the walking beam will accelerate its speed, and it will move freely relatively to disk 8, allowing the tools to drop freely. When the pitman reaches its upward limit of movement the crank will remain stationary until the lug on the constantly rotating shaft comes around into engagement therewith. Two of the pins 10 will first contact with the crank and yield, absorbing the force of the initial contact between the lug and crank.

The other two pins in the lug are for the purpose of taking up shock when the shaft rotates in the opposite direction, although they might sometimes serve to absorb a shock if the crank should be carried around too far on the downward drop of the tools.

Various changes and modifications may be made in the detail construction of the device within the contemplation of my invention, and within the scope of the appended claims.

What I claim as my invention is:

1. A crank mechanism comprising a driven shaft, a crank loosely mounted thereon, means fixed to said shaft having a laterally projecting portion having two crank engaging faces thereon adapted to move the crank, and yieldably supported contact members on each of said faces of said projecting portion for engagement with the crank.

2. A crank mechanism comprising a driven shaft, a crank loosely mounted on the shaft,

a disk secured to said shaft, means on the 1 disk projecting into the path of movement of the crank whereby said projecting means may transmit motion to the shaft and a yieldably projected contact pin on said projecting means perpendicular thereto.

3. A crank mechanism comprising a driven shaft, a crank loosely mounted on the shaft,

a disk secured to said shaft, means on the disk projecting into the path of movement of the crank whereby said projecting means may transmit motion to the crank, a slidable contact pin on said projecting means, a spring for urging the contact pin into projected position, and means for varying the pressure of the spring.

4. A crank mechanism for drilling rigs comprising a driven shaft, a crank loosely carried thereon. a disk secured to said shaft having a laterally extending lug thereon projecting into the path of movement of the crank, said hi having two crank engaging faces thereon disposed in a plane transverse to the disk, said faces being so located as to permit of said crank having only substantially 180 degrees of movement between them.

5. A crank mechanism for drilling rigs comprising a driven shaft, a crank loosely carried thereon, a disk secured to said shaft having a laterally extending lug thereon projecting into the path of movement of the crank, said lug having two crank engaging faces thereon disposed in a plane transverse to the disk, said faces being so located as to permitof said crank having only substantially 1.80 degrees of movement between them, and resilient crank engaging means on each face.

In testimony whereof I afiix my signature.

EDGAR E. GREVE.

Images