US2174102A - Lubricated cutter mounting - Google Patents

Description

Sept 26, 1939 A. c. cATLAND 2,174,102

LUBRICATED CUTTER MOUNTING Filed March 9, 1938 55 5:1114; 5713 wf/y Patented Sept. 26, 1939/y UNITED STATES PATENT OFFICE LUBRICATED CUTTER MOUNTING Alfred C. Catland, Alhambra, Calif., assignor to Globe Oil Tools Company, Los Nietos, Calif., a corporation of California Application March 9, 1938, Serial No. 194,779

8 Claims.

5 provide an improved long-wearing self-lubricated bearing or mounting for the rotatable cutter of a well drilling tool.

The bearings of the cutters provided on rotary well drilling tools wear very rapidly due to the 10 abrasive action of the rotary mud and cuttings in the Well and in some instances wear out before the teeth of the cutters. Attempts have been made to exclude the well iiuids from the cutter bearings by providing the bearings with packing washers andl similar sealing` means. Such attempts have been successful in part but it has been found that the well fluid and thc abrasive matter nds its way into the bearings around or past the packing washers and causes excessive wear of the bearings.

Another object of this invention is to provide a bearing for a cutter of a well tool that embodies means for maintaining the bearing packed or lled with lubricant whereby the well uids and abrasive matter cannot reach the active' bearing parts.

Another object of this invention is to providel a cutter mounting or cutter bearing that may be completely packed with lubricant before the well tool is run into the well and that has means for automatically introducing more lubricant to the bearing as the tool is operated, thereby eliminating any air pockets that may be present in the bearing and maintaining a pressure on the lubricant in the bearing to prevent the entrance of abrasive matter.

Another object of this invention is to provide a cutter bearing of the character mentioned embodying a novel pump means operated by the rotating cutter that feeds or forces lubricant to the active parts of the bearing as the tool is operated in the well.

Another object of this invention isto provide a bearing means of the character mentioned in which the lubricant in the bearing is maintained under a pressure equal to or greater than the pressure on the well uid so that the well fluid is prevented from entering the bearing.

Another object of this invention is to provide a cutter mounting or cutter bearing of the character mentioned in which the lubricator or lubricating means is entirely contained in the bearing, making it unnecessary to provide ports or passages in the tool body and materially simplifying the general tool construction.

(Cl. Z55-71) A further object of this invention is to provide a cutter bearing of the character mentioned in which the lubricating means is simple and inexpensive to manufacture and does not materially complicate the bearing construction.

The various objects and features of my invention will be fully understood from the following detailed description of a. typical preferred form of the invention, throughout which description reference is made to the accompanying drawing 10 in which:

Fig. 1 is a side elevation of a rotary well drilling tool with a portion broken away to illustrate a cutter mounting means of the character provided by the invention. Fig. 2 is an enlarged 15 fragmentary vertical detailed sectional view of the bearing means, the cutter and the adjacent parts. Fig. 3 is an enlarged fragmentary `detailed sectional view taken as indicated by line 3--3 on Fig. 2 showing the cam approaching the 20 valve. Fig. 4 is a view similar to Fig. 3 showing the cam actuating the valve. Fig. 5 is an enlarged fragmentary vertical detailed sectional view of the bearing means showing the pump mechanism and Fig. 6 is an enlarged fragmen- 25 tary transverse detailed sectional View taken as indicated by line 6-6 on Fig. 5.

The cutter bearing means or mounting means of the present invention may be embodied in well tools of various types and may be employed to 30 carry or support rotating cutting elements of different forms. In the drawing I have shown the invention embodied in a bearing for the roller cutter of a well drilling bit. It is to be understood that the invention is not to be con- 35 strued as limited or restricted to the speciiic form or application of the invention about to be described but that it is to be taken as including any features or modifications that may fall with- Ain the scope of the claims. 40

The well bit illustrated in the drawing is a rotary well drilling tool comprising a body I0 to be connected with the lower end of a rotary well drilling string. The body I0 has sets of spaced depending legs II and I2 and cutters I3 45 are arranged between the legs Il and I2. The opposing surfaces of the adjacent legs Il and I2 slope downwardly and outwardly with respect to the central vertical axis of the bit. The cutters I3 are tapered or truste-conical roller cutters 50 having peripheral cutting teeth I4. Central longitudinal openings I5 extend through the cutters I3. The cutters I3 are the outer cutters oi the bit and the bit includes cross cutters or inner cutters I6. The bearing means for the several 55 cutters of the bit may be similar or identical and I will proceed with a detailed description of the means for rotatably supporting one of the cutters I3, it being understood that such description may apply to the bearings for the other cutters. o

The lubricated cutter mounting means of the present invention includes, generally, a supporting pin I1 extending between two spaced legs II and I2 and having a lubricant chamber I8, a bushing or bearing member I9 on. the pin I1 within the opening I5 of a cutter I3, anti-friction members or parts 20 supporting the cutter I3 on the bearing member I9 and means 2I operated by the rotating cutter I3 to pump or deliver lubricant from. the chamber I8 to the opening I5 of the cutter.

The pin I1 is provided to carry the bearing member I9 and its cutter I3. The pin I1 extends between and is supported by the spaced parallel body legs II and I2. The leg II has a downwardly and inwardly inclined transverse opening 22 and the leg I2 has an aligned correspondingly inclined opening 23. The pin I1 is passed outwardly through the opening 22 and has its outer portion threaded in the opening 23. A suitable head is provided on the inner end of the pin I1 and is received in the opening 22. The outer end of the pin I 1 may be peened over at 24 to prevent the pin from becoming unthreaded.

The chamber I8 in the supporting pin I1 is provided to contain what may be termed a secondary or auxiliary supply of lubricant. The chamber I8 may be formed by drilling a longitudinal bore in the pin I1 from its inner end and then closing the end of the bore with a plug 25. The plug 25 may be welded to the pin I1 at 26. A longitudinal opening 21 is provided in the Plug 25 to admit lubricant to the chamber I8. It is preferred to provide the opening 21 with a valved fitting, As shown in the drawing a suitable grease gun tting 28 may be threaded in the opening 21 and may have its outer part received in an enlarged end portion of the opening. The lubricant chamber I8 is preferably of substantial length to contain a substantial quantity of the lubricant.

The bushing or bearing member I9 is received in the cutter opening I5 with suitable clearance and is supported on the pin I1 between the spaced legs II and I2. The opposite ends of the member I9 may be flat to bear against the opposing sides or surfaces of the legs II and I2. The member I9 may be a cylindrical spool-like member provided at its outer end with a radial .flange 30. The flange 30 is partiallyreceived 1n a socket 3I in the outer end of the cutter. Lugs 32 and 33 are provided on the member I9 to cooperate with the lower ends of the legs II and I2, respectively. The lugs 32 and 33 serve to position the member I9 and to prevent it from rotating. The lug 33 may be welded to the leg I2 at 34.

The anti-friction members or parts 20 are provided to support the cutter I3 on the bearing member I9 for free rotation. In the preferred construction the anti-friction bearing parts 2B are in the nature of balls. Spaced annular ball races 35 are provided in the wall ofthe cutter opening I5 and oppose similar ball races 36 in the periphery of the bearing member I9. The balls 0r bearing parts 20' occupy the `pairs of spaced opposed races 35 and 36, there .being a series of the parts 20 in each pair of races. The races 35 and 36 are of such depth that the bearing parts a 20 transmit end thrusts in both directions as well as the radial thrusts and may form the sole means for rotatably supporting the cutter I3 on' inserted in the races 35 and 36 plugs 39 are arranged in the bores 31. The plugs 39 are passed into the bores 31 from their inner ends and the outer ends of the plugs are shaped to form continuations of the-races 36. Keys 40 are provided on the inner ends of the plugs 39 and cooperate with keyways 4I formed in the wall of the opening 38 to prevent turning of the plugs and to limit outward movement of the plugs. The pin I1 cooperates with the inner ends of the plugs 39 to limit their inward movement. The above described means for facilitating the insertion of the balls or bearing parts 20 in the races 35 and 36 is fully described and claimed in my co-pending application entitled Rock bit, Ser. No. 191,243, led February 18, 1938.

In accordance with the invention all the spaces within the bearing and cutter assembly are lled with lubricant before the assembly is mounted on the bit body I0 and before the bit is run into the well. This packing of the cutter and bearing assembly with lubricant is carefully done to eliminate as far as possible voids or air spaces in the assembly. Packing means are preferably incorporated in the assembly to prevent or lessen the loss of the lubricant and the entrance of the well fluids to the bearing. An annular groove 42 is provided in the inner side of the flange 30 to oppose the adjacent end of the cutter I3. A washer 43 of felt or the like is arranged in the groove 42 to seal with the wall of the socket 3I in the end of the cutter I3. The Washer 43 prevents or reduces the loss of lubricant outwardly between the cutter I3 and the flange 30 and prevents or lessens the entrance of well fluid into the outer end of the bearing. An annular groove 44 is provided in the periphery of the member I9 adjacent its inner end and a washer 45 of felt or the like is set in this groove to seal with the wall of the cutter opening I5. The washer 45 serves to prevent or lessen the loss of lubricant from the inner end of the cutter opening I5 and to prevent or lessen the entrance of well uid to the openings.

The means 2| is provided to discharge or force lubricant from the chamber I8 to the cutter opening I5 to remove all voids or air spaces in the bearing and to maintain the bearing charged or full of lubricant as the tool is operated in the well, to materially reduce the friction and to prolong the life of the bearing. 'I'he means 2| includes a follower or piston 46 in the lubricant chamber I8. The piston 46 faces and moves toward the plug 25 and is urged against the bodyv of lubricant in the chamber I8 by a spring 41. The spring 41 is arranged under compression between the'piston 46 and the adjacent end wall of the chamber I8. A port 48 extends through the pin I1 from said end wall of the chamber -II to the outer end of the pin to place the end portion of the chamber I8 in communication with the Well. The port 49 permits the pressure on the duid in the well to 'act against thepiston 46 and the lubricant in the chamber I8 and to maintain the pressure on the lubricant in the bearing equal to or in excess of the external pressure as will be more fully described.

The means 2I further includes an ejecting .mechanism or pump mechanism for forcing lubricant from the supply chamber I8 to the opening I5 in the cutter I3 to lubricate the anti-friction parts 20 and the races 35 and 36. An annular groove 49 is formed in the periphery of the pin I1 and a port 58 is provided in the pin. to extend from the chamber I8 to the groove 49. The port 50 preferably has its inner end adjacent the plug 25. A cylinder opening 5I is provided in the bearing member I9 and extends through the wall of the member Yfrom its opening 38 to its periphery. It is preferred to provide the cylinder opening 5I in the lower portion of the member I9 so that the lubricant passed therethrough is delivered tothe loaded side of the bearing. 'Ihe outer end of the cylinder opening 5I is spaced between the races 36 and the inner end of the opening 5I communicates with the groove 49. The outer portion of the cylinder opening 5I is reduced in diameter to provide an inwardly facing shoulder or seat 52 on the wall of the opening.

An insert or annular valve seat 53 is force-fitted or otherwise secured in the inner portion of the cylinder opening 5I. An inwardly seating ball 5`4 cooperates with the seat 53 to control the introduction of lubricant from the groove 49 to the opening 5I. The ball 54 may be termed a' foot valve. A tapered valve 55 seats outwardly against the seat 52 to control the discharge of lubricant from the opening 5I to the opening I5 in the cutter I3. The valve 55 has a stem 56 extending outwardly through the cylinder opening 5I to project from the periphery of the bearing member I9. The stem 56 is grooved or triangular in cross section to allow for. the passage of lubricant outwardly past or around it. 'I'he stem 56 slidably cooperates with the wall of the reduced portion of the opening 5I to guide the valve 55. Spring means is provided to urge the valves 54 and 55 to their closed positions. A helical spring 51 is arranged in the opening 5I and is under compression between the ball valve 54 and the valve 55. The spring 51 normally holds the two valves 54 and 55 closed and is yieldable to allow the valves to open.

The means 2| includes a cam means to operate or reciprocate the valve 55 to create a pumping action in the cylinder opening 5I and to discharge lubricant from the opening 5I into the cutter opening I5. The outer end of the valve .stem 56 is tapered or rounded. The valve 55 cooperates with the seat 52 to limit the outward travel of the stern 56 and its cooperation with'the seat normally holdsthe stem 56 where its outer end clears the wall of the opening I5. A cam 58 is provided on the wall of the opening I5 to cooperate with the valve stem 56. In practice the cam 58 may be welded on the wall of the opening I5.. The active face 59 of the cam 58 slopes gradually from the wall of the opening I5 rearwardly relative to the direction of rotation of the cutter I3. The sloping cam face 59 cooperates with the. end of the valve stem 56, once during each revolution of the cutter to force the valve 55 inwardly from its seat 52. This inward movement of the valve 55 is accompanied by the discharge of lubricant from the opening 5I to the cutter opening I5.

During the operation of the bit the bit body I is rotated and fed downwardly in the usual manner so that the cutters I3 and I6 rotate on their axes and roll on the earth formation at the bottom of the wellbore. Referring to the cutter I3 and its bearing means described in detail above, thebearing for the cutter is thoroughly packedwith grease or other lubricant before the assembly is applied to the bit body I0. The chamber I8 is charged or lled with a supply of lubricant. duced to the. chamber I8 under pressure by a grease gun or the like connected with the ftting 28. In practice the chamber I 8 may be completely lled with the lubricant to move the piston 46 to a position such as illustrated in Fig. 2 of the drawing. Following the charging of the chamber I8 the tting 28 may be sealed off with welding or the like if this is believed necessary. It is to be understood that the chamber I8 and the port 50, the groove 49 and the opening 5I communicating with the chamber and the cutter opening I5 are all lled or packed with the lubricant.

When the tool is operated in the well in the presence of the well liquid under pressure the external pressures act on the lubricant in the chamber I8 through the medium of the piston 46. The external pressures are admitted through the port 48 to act on thel piston 46. Thus the lubricant in the chamber I8 and the other parts of the bearing are subjected to a vpressure at least equal to the external pressures. The pressure on the lubricant in the chamber I8 and in the other parts of the bearing is augmented or increased by the spring 41 forcing the piston 46 against the. charge of lubricant in the chamber I8. Accordingly, the lubricant in the chamber I8 and in the other parts of the bearing is normally under a pressure greater than the external pres- Y sures, The lubricant under pressure in the opening I5 aids in preventing the entrance of well liquid and abrasive matter to the bearing and the felt washers 43 and 45 assist in this action. The

The lubricant may be introfelt washers 43 and 45 also serve to lessen or prevent the loss of `the lubricant under pressure from the opposite ends of the cutter opening I5.

As the cutter I3 rotates through its engagement with the earth-formation the cam 58 operates cr moves the stem 56 and the valve 55. The cam face 59 moves the valve 55 inwardly during a,

short phase of each revolution of the cutter I3 sure in the opening 5I is partially displaced by the inwardly moving valve and is allowed to pass out around the valve stem 56 to enter the cutter opening I5. During the closing or outward movement of the valve 55 a reduced pressure condition is created in the opening 5I and lubricant under pressure from thechamber I8 unseats the valve 54 -and ows' into the opening 5I.

The lubricant under pressure discharged from the opening 5I enters the cutter opening I5 at a point between the spaced races 36. This lubricant keeps the anti-friction parts 20 and the races 35 and 36 lubricated at all times. The lubricant discharged from the opening 5I to the cutter opening I5 replaces any lubricant that may leak from the bearing during operation of the tool and keeps the bearing full of grease or lubricant. Further, the lubricant under pressure discharged from the opening 5l maintains the lubricant in the bearing under a pressure equal to or greater than the external pressure so that the well iluid and solid matter has no opportunity to enter the bearing. Lubricant may be intermittently discharged from the opening 5I throughout the entire run of the drilling tool so that the anti-friction parts 20 operate in a bath of lubricant. The bearing Supplied with replacement or additional lubricant throughout the operation of the cutter I3 is subject to a minimum of wear and friction and is long wearing.

Having described only a typical preferred form and application of my invention I do not wish to be limited or restricted to the specific form and application herein set forth, but wish to reserve to myself any variations or modifications that may appear to those skilled in the art or fall within the scope of the following claims.

Having described my invention, I claim:

1. Means for lubricating a cutter assembly of a well drilling bit, the assembly including a cut ter having an opening, a supporting pin passing through the opening, and anti-friction bearing means carried by the pin and rotatably supporting the cutter, said lubricating means comprising Walls in the pin defining a lubricant chamber, walls in said bearing means defining a passage for conducting lubricant from the chamber to the cutter opening, there being port means in the pin subjecting the lubricant in the chamber to the well pressures to urge-it through the passage, and spring means increasing said pressure on the lubricant.

2. Means for lubricating the assembly of a well bit cutter having an opening, a supporting pin passing through the opening, a bearing membcr on the pin and spaced series of anti-friction parts rotatably supporting the cutter on said member, the lubricating means comprising walls in the pin defining a lubricant chamber, walls in said member defining a passage for conducting lubricant from said chamber to the exterior of the member between said spaced series of parts, a spring urged piston in the chamber feeding the lubricant to the passage, a pump element in the passage for ejecting lubricant therefrom, and a cam on the Wall of the cutter opening operating the pump element.

3. Means for lubricating the assembly `of a lcutter having an opening, a supporting pin passing through the opening, a bearing member on the pin and spaced series of anti-friction parts rotatably supporting the cutter on said member, said lubricating means comprising Walls in the pin defining a lubricant chamber, walls in said member defining a passage for conducting lubricant from said chamber to the exterior of the member between said spaced series of parts, a spring urged piston in the chamber feeding the lubricant to the passage, a pump element in the passage for ejecting lubricant, a foot valve in the passage preventing the return of lubricant therefrom to the chamber, and a cam on the wall of the cutter opening operating the pump element.

4. Means for lubricating a well tool cutter assembly having a rotatable roller cutter, a bushing extending through the cutter and having a lubricant duct leading to the interior of the cutter, and a pin carrying the bushing and having a lubricant chamber communicating with the duct to supply lubricant thereto, the lubricating I means comprising pump means in the duct operable to force the lubricant into the cutter, and a part on the cutter for operating the pump means during rotation of the cutter.

5. Means for lubricating a well tool cutter assembly having a rotatable roller cutter, a bushing extending through the cutter and having a lubricant duct leading to the interior of the cutter, and a pin carrying the bushing and having a lubricant chamber communicating with the duct to supply lubricant thereto, the lubricating means comprising, means for forcing lubricant from the chamber to the duct, pump means in the duct operable to force the lubricant into the cutter, and a part on the cutter for operating the pump means during rotation of the cutter.

6. Means for lubricating a well tool cutter assembly having a rotatable roller cutter, a bushing extending through the cutter and having a lubricant duct leading to the interior of the cutter, and a separable pin carrying the bushing and having a lubricant chamber communicating with the duct and a port leading from the chamber to the exterior of the pin to admit fluid pressure from` the well to the chamber, the lubricating means comprising a piston in the chamber acted on by said fluid pressure to force the lubricant to the duct, a spring acting on the piston to assist in said action of the fluid pressure, valve means controlling the discharge of lubricant from the duct to the interior of the cutter, and a part on the cutter for opening the valve means during rotation of the cutter.

7. Means for lubricating a well tool cutter assembly having a rotatable roller cutter, a bushing extending through the cutter and having a lubricant duct leading to the interior of the cutter, and a separable pin carrying the bushing and having a lubricant chamber, a port in one end communicating with the chamber to admit fluid pressure to the chamber and a port in the other end leading to the chamber, the lubricating means comprising a fitting at the last named port for admitting lubricant to the chamber, a piston in the chamber acted on by the said fluid pressure to force the lubricant from the chamber to the duct, valve means at the duct for controlling the discharge of the lubricant therefrom and a part on the rotating cutter for opening the valve means.

8. Lubricating means for the assembly of a rotatable cutter, and a tubular bushing in the cutter, the bushing having a duct leading from its interior to the interior of the cutter, the lubricating means comprising a separable pin extending through the bushing and having a lubricant containing chamber in communication with the said duct, pump means at s aid duct for pumping the lubricant into the cutter, and a part on the cutter operating the pump means during rotation of the cutter.'

ALFRED C. CA'I'LAND.

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