US2175094A - Cathead - Google Patents

Description

P. M. REA

Oct. 3, 1939.

CATHEAD 2 Sheets-Sheet l aux Filed Feb. 20, 195? Rm Y I m H 0 MM 5 m I P/Ii/ BY P. M. REA

Oct. 3, 1939.

CATHEA-D Filed Feb. 20, 1937 2 Sheets-Sheet 2 INVENTOR gimp M fi Q.

A TORNEY Patented Oct. 3, 1939 E ATENT OFFlCE GATHEAD Philip M. Rea, Oklahoma City, Okla.

Application February 20, 1937, Serial No. 126,841

7 Claims.

This invention relates to cat-heads used in connection with the draw-works of a well dril1- ing rig for providing the power required in breaking the tool joints in a string of drill pipe or the like.

The principal object of the invention is to provide a cat-head with a simple and reliable means for effecting operative connection and disengagement of the driven element with the countershaft of the draw-works.

It is also an important object of the invention to provide a cat-head construction which permits of ready assembly and secure retention of the parts.

Further objects of the invention are to provide an improved means for manually effecting engagement of the latch-dog with a driven quill about which the driven element of the cat-head is rotatably mounted; to provide a cat-head construction whereby the driving forces are exerted in the direction of rotation so that there are no end thrusts imparted to the driving and driven elements; and to provide for engaging and tripping of the latch-dog without resultant ill effects on the draw-works.

In accomplishing these and other objects of the invention, as hereinafter pointed out, I have provided improved details of structure, the preferred form of which is illustrated in the accompanying drawings, wherein:

Fig. 1 is a perspective view of a portion of a draw-works equipped with a cat-head embodying the features of the present invention.

Fig. 2 is an enlarged detail section through the cat-head illustrating driving engagement of the latch-dog with the driving quill.

Fig. 3 is a vertical section through the cathead on the line 33 of Fig. 2, illustrating the latch-dog in disengaged position but ready to be moved into position to be engaged by a latchdog engaging face of the quill.

Fig. 4 is a similar section showing the latchdog in engaged position and moving toward the point where the latch-dog is ordinarily disengaged from the quill.

Fig. 5 is a section on the line 5-5 of Fig. 2 illustrating the latch-dog control rollers entering the return track to hold the latch-dog out of driven engagement with the quill during reverse rotation of the driven element.

Fig. 6 is a detail view of the latch-dog, one of the control rollers being shown in section.

Fig. 7 is a detail perspective view of the housing sections shown in disassembled spaced relation to better illustrate the track-ways therein.

Fig. 8 is a detail perspective view of the driving quill, the driven element, the latch-dog and the spool which cooperates with the quill in retaining the driven element.

Referring more in detail to the drawings: 5'

i designates a draw-works including jack posts 2 mounted on a derrick platform 3 and support ing the usual counter-shaft 4 and line shaft 5 from which the rotary drilling tools are operated as in conventional practice. The end of the line shaft 5 projects beyond the outer post 2 to mount a cat-head 6 which is constructed in accordance with the present invention.

The cat-head includes a quill I having a sleevelike body 8 provided with a longitudinal bore 9 to snugly engage the projecting end of the shaft 5. The quill is keyed to the shaft 5 by means of a spline I engaging in a keyway H formed in the side of the shaft and in a registering key recess E2 that is formed in the inner face of the sleeve-like body, as best shown in Figs. 2 and 3. The quill is of suflicient length to accommodate a driven element M which operates a jerk line presently described and to mount a spool l that is used in certain of the drilling operations and which cooperates with the quill in retaining the driven element. The outer periphery of the quill is shaped to provide an annular stop flange M3 on the end adjacent the post 2, and spaced from the stop. flange a distance corresponding to the width of the driven element is an annular shoulder I! that is formed by reducing the outer diameter of the quill to correspond to the inner diameter of the spool. Formed in the outer surface of the quill, at a point midway between the flange l6 and the shoulder H. is a series of arcuate recesses or grooves l8 having bottoms !9 extending from a point on the periphery of the quill to a spaced point inset from the surface of the quill to provide a latch-dog engaging face 29. The side Walls 2! and 22 of the recesses extend substantially parallel and are spaced apart a distance slightly greater than the width of the latch-dog, later described.

The driven element includes a collar 23 having a central internal band 24 of a diameter to freely and rotatably engage the notched portion of the quill and having its ends counter-bored to provide annular bearing recesses 25 and 26 in which are mounted sets of roller bearings 21 and 28 to reduce tendency of the collar to drag upon the quill when the collar is disengaged from driving relation therewith as later described. The outer periphery of the bushing is provided 55 with an annular groove 2& separating annular bearing faces 36 and 3H which engage in bushings 32 and 33 located within the sections as and 35 of a housing 36.

Formed in the groove 29 and extending completely through the wall of the collar 23 is a slot 3'! in which a latch-dog 38 is adapted for movement as later described. The slot 3'5 includes a portion 39 of slightly greater width than the groove 29 to allow free movement of the latchdog lug. The latch-dog is best illustrated in Fig. 8 and includes a substantially rectangular lug portion ill that extends freely through the portion 39 of the slot 3i and is adapted to engage in the respective notches of the quill to effect driving engagement with the faces 2%] as later described. The latch-dog includes a tail portion il pivotally mounted within the narrow portion of the slot 3? on a pivot pin t2 that extends through an opening &3 in the tail portion of the latch-dog and has its ends mounted in openings 44 formed in the sides of; the slot 31 as best illustrated in Fig. 8.

Carried by the latch-dog at a point directly above the lug All, are laterally extending spindles 45 and 46 carrying rollers ll and 58. Formed in the latch-dog is a tapered socket :9 in which one end of a jerk line 56 is babbitted as shown at 5| in Fig. l. The jerk line extends over the tail portion of the latch-dog and operates within the groove 29. Its opposite end is adapted to be connected with a wrench on the upper section of a tool joint (not shown) as in well known practice.

The housing sections 3t and 35 are of substantially the same construction and include annular web or disk- like wall portions 52 and 53 having axial openings 54 and 55 of suitable diameter to pass freely over the quill and to accommodate the bushings 32 and 33, previously mentioned. Formed in the web portions 52 and 53, in concentric relation with the bushed open ings, are inner and outer arcuate track-ways 5651 and 58-59 which are connected at their respective ends by transfer grooves Eli-6| and 6263 respectively. The inner groove conforms in width to the diameter of the rollers 41 and 48 on the latch-dog and are of a depth to freely accommodate the length of the rollers. The outer grooves are of similar depth but may be of greater width than the diameter of the rollers as shown in Fig. 5. The track-ways are thus separated by arcuate flanges 64 and 55 having inner edges 66 and 67 spaced apart to forman annular pathway through which the latch-dog is adapted to move as later described. The ends SSS-69 and lll'll of the flanges are slightly rounded at their juncture with the track-ways to facilitate transfer of the rollers from, one groove to the other. The transfer grooves 6i and 63 are rounded, as at T2 and 13, to provide throw-out portions at the terminal ends of the inner track-ways to guide the rollers into the outer track-way for return of the driven collar under pull of the jerk line as later described.

In order to transfer the rollers from the outer groove to the inner groove, and thereby effect engagement of the lug All with one of the recesses of the quill, I provide an elevating device including a lever i l extending through slots '15 and 16 provided in the outer annular flange of the housing sections as best shown in Fig. 7. The lever is pivoted on a pin Ti that is carried by spaced ears l8 and ill on the respective housing sections. The inner end 8E3 of the lever projects a sufficient distance within the housing to adapt it for movement entirely across the width of the outer track-ways and slightly within the space at the ends E59 of the flanges 64 and 655, as shown in Figs. 4 and 5. The outer end 8! of the lever is connected with a control line 82 whereby the lever may be actuated to eifect transfer of the rollers on the dog from the outer track to the inner track and thereby move the lug into position to be engaged by one of the latch engaging faces of the quill. The outer flanges are of suflicient depth to close the space circumferentially of the latch-dog passage, however, the portions thereof adjacent and between the terminal ends of the track-ways are notched as at 33 and B4 to provide a slot through which the jerk line is passed, as clearly shown in Figs. 1, 3 and 4, for connection with the wrench as above mentioned.

The housing sections are provided with pairs of radial lugs 85 and 85 through which fastening devices, such as bolts 3?, are extended to secure the sections together. The section 34 has an attaching flange 88 whereby the housing is secured to the post 2 to prevent rotation thereof.

The spool l5 includes a sleeve-like body 89 having an inner diameter to pass over the reduced portion of the quill as shown in Fig. 2, and is keyed thereto by a spline 9Q engaged in registering grooves formed within the outer periphery of the quill and in the inner diameter of the spool. The spool has an annular flange 9! abutting the annular shoulder l? and which cooperates with the flange IE to retain the roller bearings as shown in Fig. 2. In order to prevent lateral displacement of the spool, the outer end 92 is recessed to accommodate a plate 93 that is secured to the end of the quill by fastening devices, such as cap screws 94, extending through openings 95 in the plate and into threaded sockets formed in the end of the quill as shown in Fig. 8.

In assembling a oat-head constructed as described, the key it is inserted in the recess !2 of the quill and the quill is slid over the projecting end of the shaft 5 so that the key enters the groove of the shaft. The housing section 34 is then sleeved over the quill so that the outer face of the web portion thereof engages the flange it. The driven element carrying the latch-dog is then sleeved over the quill and the roller bearings inserted in the bearing recesses 25 and 2t. When the driven element is properly assembled, the annular bearing portion 3E3 thereof engages within the bushing of the housing section 3 3 so that it is rotatably mounted therein. The jerk line is extended around the driven element so that it lies within the groove 28. The roller i! is located in the transfer groove fill of the housing section M, for example as shown in Fig. 3. The other housing section is then sleeved over the bearing portion 3! of the driven element whereupon the bolts 8'1 are passed through the ears and 86 to secure the sections together. The flange 83 of the section ta l is then attached to the post 2 to prevent relative rotative movement of the housing. The lever "it is then applied so that the inner end thereof engages under the latch-dog as shown in Fig. 3, and connected with the control line 82. The spool is then sleeved over the outer end of the quill after which the key 90 is inserted to secure the spool in driving relation therewith. After insertion of the key the plate 93 is applied to the end of the qull to complete the assembly.

In using a cat-head assembled as described, the normal position of the latch-dog is as illustrated in Fig. 3, with the head of the latch-dog resting upon the forward end 80 of the lever 14, and with the rollers located in the transfer passages 62. In this position the lug on the latch-dog is out of the path of travel of the latch engaging faces 20. The quill therefore rotates freely within the driven element and the driven element remains stationary due to the fact that the friction of the surfaces 30 and 3| with the housing bushings is great enough to resist any tendency for the driven element to rotate. Movement of the driven element is also resisted by the jerk line. After the jerk line has been connected with the wrench used in breaking the tool joint, the latch-dog is rendered effective by pulling on the cable 82 to cause the forward end of the lever 14 to raise the latchdog into position where the rollers 41' and 43 will enter the inner track-ways. In this position the lug on the latch-dog is moved into peripheral contact with the quill and into one of the recesses to be engaged by the latch dog engaging face 20. .The quill therefore picks up the driven member through its connection with the latch-dog, causing it to rotate in a counter-cloclo wise direction, Fig. 3. Rotation of the driven element causes the jerk line to wrap about the periphery of the groove 29 as shown in Fig. 4 to exert a pull on the wrench. The rollers 41 and 48, moving in the inner cam groove, keep the lug of the latch-dog in engagement with the quill so that the clutching engagement is maintained until the rollers engage the rounded portions 13 of the transfer grooves 6! and 63. As soon as the rollers engage these portions of the grooves, they are cammed outwardly to lift the lug out of engagement with the quill and to guide the rollers into alignment with the outer trackways, as shown in Fig. 5. When a pull is exerted on the jerk line, the driven member is caused to rotate in a clockwise direction (Fig. so that it is returned to its starting point, as illustrated in Fig. 3. Due to the fact that the rollers remain in the outer track-ways the latch-dog is held out of driving engagement with the quill. As soon as the rollers contact the lever I4, they cause the forward end of the lever to swing downwardly, restoring the lever to its original position so that the latch-dog can be again lifted thereby into engagement with the driving portions of the quill.

From the foregoing it is obvious that I have provided a cat-head construction whereby the driving forces are all exerted in the direction of rotation so that there are no end thrusts imparted to the driving or driven elements. The engagement of the latch-dog with the quill, and also the trippingof the latch-dog from engagement with the quill, are accomplished without shock and resultant ill eifects on the draw-works. The pull on the line is also applied directly into the shaft and at a point close to the shaft support on the draw-works.

What I claim and desire to secure by Letters Patent is:

1. In combination with a rotatable driving member having latch-dog engaging portions and bearing races on the respective sides of said engaging portions, a driven member including a collar rotatably mounted on the driving member and having races cooperating with the first named races, antifriction bearings for said races, a latchdog movably supported on the driven member and adapted to engage the latch engaging portions on the driving member, a housing for said driven member, means in the housing forming communicating primary and return trackways,

means for automatically shifting the latch-dog from the primary to the return track-way and disengaging the dog from the driving member, and manually operable means at the opposite end of the track-ways for returning the latch-dog to the primary track-way and engaging said dog with the driving member.

2. In combination with a rotatable driving member having latch-dog engaging portions, a driven member including a sleeve-like body rotatably mounted on the driving member, a latchdog movably supported on the driven member and adapted to engage the latch engaging portions on the driving member, a housing for said driven member and having inner and outer track-ways interconnected by transfer-ways, guide means on the latch-dog operable in said ways to respectively maintain engagement of the latch-dog with the driving member during rotation of the driven member by the driving member and disengagement of the latch-dog upon reverse rotation of the driven member, and means for effecting transfer of the guide means from one of the track- Ways to the other to effect shifting of the latchdog into engagement with the engaging portions of the driving member.

3. In combination with a rotatable driving member having latch-dog engaging portions, a driven member including a sleeve-like body rotatably mounted on the driving member, a latchdog movably supported on the driven member and adapted to engage the latch engaging portions on the driving member, a housing for said driven member and having inner and outer track-ways interconnected by transfer-ways, a roller on the latch-dog operable in said track-ways to respectively maintain engagement of the latch-dog with the driving member during movement of the driven member by the driving member and disengagement of said dog during reverse movement of the driven member, means for effecting transfer of the roller from one of the track-ways to the other for shifting the latch-dog into engagement with the engaging portions of the driving member, and means adapted for engagement by the roller to automatically disengage the latchdog.

4. In combination with a rotatable driving member having latch-dog engaging portions, a driven member including a sleeve-like body rotatably mounted on the driving member, a latch-dog movably supported on the driven member and adapted to engage the latch engaging portions on the driving member, a housing for said driven member, having inner and outer track-ways interconnected by transfer-Ways, guide means on the latch-dog operable in said ways to respectively maintain engagement of the latch-dog with the driving member during movement of the driven member by the driving member and disengagement therefrom during reverse movement of the driven member, means for effecting transfer of the guide means from one of the trackways to the other for shifting the latch-dog into engagement with the engaging portion of the driving member, means for engagement by the guide means to disengage the latch-dog, and a jerk line connected with the driven member, adapted to wind upon said driven member during driving thereof by the driving member and whereby the driven member is rotated reversely upon unwinding of the line.

5. In combination with a rotatable driving member having latch-dog engaging portions, 3.

driven member including a sleeve-like body rotatably mounted on the driving member, a latchdog movably supported on the driven member and adapted to engage the latch engaging portions on the driving member, a housing for said driven member and having inner and outer trackways interconnected by transfer-Ways, a roller on the latch-dog operable in said ways to respectively maintain engagement and disengagement of the latch-dog with the driving member, means for efiecting transfer of the roller from one of the grooves to the other to move said latch-dog into engaging relation with said engaging portions of the driving member, means engageable by the roller to disengage the latchdog, and a jerk line connected with the latch-dog and adapted to be wound on the driven member when the latch-dog is engaged with the driving member and to be unwound from the driven mem ber to return the driven member to its original position.

6. In combination with a driving member ineluding a rotatable driving shaft, a quill sleeved on the shaft and having latch-dog engaging portions, means fixing the quill to the shaft, a driven member sleeved on the quill and having a circumferential opening, a jerk line, a latch-dog connected to the jerk line having a tail portion pivoted in said opening, said tail portion being adapted to cooperate with the driven member to support the jerk line when the latch-dog is engaged with the quill, track-ways spaced at different distances from the driving member for maintaining engagement and disengagement of the latch-dog relatively to said engaging portions of the driving member, means for effecting engagement of the latch-dog with said engaging portions of the driving member to drive the driven member, and means for effecting automatic release of the latch-dog.

7. In combination with a rotatable driving member having latch-dog engaging portions, a driven member rotatable about the axis of the driving member, a latch-dog movably mounted on the driven member and adapted for engaging said engaging portions of the driving member, a member surrounding the driving member forming interconnected inner and outer track-Ways, and a jerk line connected with the latch-dog adapted to Wind on the driven member, guide means on the latch-dog adapted for travel in one track-Way when the latch-dog is engaged and in the other track-Way when the latch-dog is disengaged, and means at the ends of the trackways for shifting the guide means between the track-ways and the latch-dog to and from engagement with the driving member.

PHILIP M. REA.

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