US4572306A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Journal bushing drill bit construction
Assignee: SUNRISE ENTERPRISES Ltd
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Filing: 1984-12-07
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Granted: 1986-02-25
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Expires: 2004-12-07
Abstract
Abstract An earth boring drill bit having roller cutters which are rotatably supported on journals by bushings. At least one of the bushings is formed by a plurality of bushing segments which are positioned about a circular bearing surface having thrust shoulders at each end thereof. The roller cutter elements are assembled about the bushing segments in heated condition, by press-fitting to establish a firmly seated relationship between the cutter and bushing segments upon cooling of the cutter. The rotary cutter is then secured to the bushing segments by means of a locking element to prevent inadvertent disassembly during drilling operations. End portions of the bushing segments engage hardened bearing inserts of cutter support legs to minimize wear during drilling operations. A circular sealing element positioned about the bushing segments establishes sealing engagement with the cutter support legs to prevent ingress of contaminants and egress of lubricant during drilling activity.
Inventors
- 👤 Dennis D. E. Dorosz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 07:53
CPC Classifications
E; E21; E21B; E21B10/00; E21B10/08; E21B10/20; E21B10/22
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
283 words
A rotary earth boring bit, comprising: (a) a body structure adapted for threaded connection to a string of drill stem, said body structure defining a plurality of cutter support legs, each forming planar surface means; (b) journal means extending transversely from each of said cutter support legs and being oriented in normal relation with said planar surface means, said journal means defining bushing retainer means and reduced diameter bearing surface means of smaller dimension than said bushing retainer means; (c) rotary cone cutter means defining external cutter teeth and forming an internal journal and bushing receptacle, said rotary cutter means forming planar cutter surface means; (d) segmented bushing means being positioned about said bearing surface means and being received in mechanically seized relation within said journal and bushing receptacle, end portions of said segmented bushing means extending beyond said planar cutter surface means for engagement with said planar surface means of said cutter support legs and maintaining said planar cutter surface means in spaced relation with said planar surface means of said cutter support legs, said segmented bushing means and said rotary cone cutter means cooperatively forming a circular seal recess intersecting said planar cutter surface means; (e) locking means being positioned about said segmented bushing means within said journal and bushing receptacle and securing said rotary cutter means in locked assembly with said segmented bushing means, whereby said rotary cutter means and said segmented bushing means are rotatably mounted on said journal means; and (f) circular seal means disposed within said circular seal recess and being positioned about said segmented bushing means and establishing a seal with said planar surface means of said cutter support legs and with said segmented bushing means.
Claim 2
Dependent Claim
283 words
A rotary earth boring bit, comprising: (a) a body structure adapted for threaded connection to a string of drill stem, said body structure defining a plurality of cutter support legs, each forming planar surface means; (b) journal means extending transversely from each of said cutter support legs and being oriented in normal relation with said planar surface means, said journal means defining bushing retainer means and reduced diameter bearing surface means of smaller dimension than said bushing retainer means; (c) rotary cone cutter means defining external cutter teeth and forming an internal journal and bushing receptacle, said rotary cutter means forming planar cutter surface means; (d) segmented bushing means being positioned about said bearing surface means and being received in mechanically seized relation within said journal and bushing receptacle, end portions of said segmented bushing means extending beyond said planar cutter surface means for engagement with said planar surface means of said cutter support legs and maintaining said planar cutter surface means in spaced relation with said planar surface means of said cutter support legs, said segmented bushing means and said rotary cone cutter means cooperatively forming a circular seal recess intersecting said planar cutter surface means; (e) locking means being positioned about said segmented bushing means within said journal and bushing receptacle and securing said rotary cutter means in locked assembly with said segmented bushing means, whereby said rotary cutter means and said segmented bushing means are rotatably mounted on said journal means; and (f) circular seal means disposed within said circular seal recess and being positioned about said segmented bushing means and establishing a seal with said planar surface means of said cutter support legs and with said segmented bushing means.
Claim 3
Dependent Claim
78 words
A rotary earth boring drill bit as recited in claim 1, wherein: (a) said cutter support legs define bearing insert receptacle means about said journal means; and (b) hardened circular bearing means is positioned within said bearing receptacle means of said cutter support legs and forms at least a portion of said planar surface means of said cutter support legs; and (c) said end portions of said segmented bushing means establish bearing engagement with said hardened bearing inserts.
Claim 4
Dependent Claim
84 words
A rotary earth boring drill bit as recited in claim 1, wherein: (a) said segmented bushing means and said rotary cone cutter means each define registering circular locking grooves of semicircular cross-sectional configuration; (b) said rotary cone cutter means defines lock insert passage means intersecting said circular locking groove of said rotary cutter means; and (c) said locking means comprises an elongated yieldable locking member capable of being inserted through said lock insert opening into the locking groove defined by said registering locking grooves.
Claim 5
Dependent Claim
77 words
A rotary earth boring drill bit as recited in claim 1, wherein: (a) said journal means defines a planar surface at the free extremity thereof; and (b) said rotary cutter means forms a planar surface defining the inner extremity of said journal and bushing receptacle, said planar surface of said rotary cutter means engaging said planar surface of said journal means to thus cooperatively limit relative axial movement of said rotary ncutter means to said journal means.
Claim 6
Dependent Claim
44 words
A rotary earth boring drill bit as recited in claim 1, wherein: each of said cutter support legs forms lubricant passage means intersecting said bearing surface means to thus provide a supply of lubricant between said bearing surface means and said segmented bushing means.
Claim 7
Dependent Claim
56 words
A rotary earth boring drill bit as recited in claim 5, wherein: said lubricant passage means includes elongated lubricant slot means formed in said journal means and extending along a major portion of said bearing surface means to thus provide for supply of lubricant along a major portion of the length of said bearing surface means.
Claim 8
Dependent Claim
64 words
A rotary earth boring drill bit as recited in claim 1, wherein: said rotary cone cutter means is assembled about said segmented bushing means and journal means in heated condition whereby upon cooling of said rotary cutter means to the temperature of said segmented bushing means and journal means, said rotary cutter means becomes seized in immovable relation relative to said segmented bushing means.
Claim 9
Dependent Claim
53 words
A rotary earth boring drill bit as recited in claim 7, wherein: said rotary cutter means is press-fitted about said segmented bushing means with said segmented bushing means assembled to said journal means while said rotary cutter means is heated to a temperature range of from about 300° F. to about 1000° F.
Claim 10
Dependent Claim
75 words
A rotary earth boring drill bit as recited in claim 1, wherein: (a) said journal means forms second bearing surface means of smaller dimension than said bearing surface means and being located on the opposite side of said bearing retainer means from said bearing surface means; and (b) second bushing means is disposed in bearing relation with said second bearing surface means and is disposed in mechanically seized relation with said rotary cone cutter means.
Claim 11
Dependent Claim
39 words
A rotary earth boring drill bit as recited in claim 9, including: (a) lubricant supply passage means extending through said journal means and having branch passages supplying lubricant respectively to said segmented bushing means and said second bushing means.
Claim 12
Dependent Claim
41 words
A rotary earth boring drill bit as recited in claim 9, wherein: said bearing surface means and said second bearing surfaces means are of generally cylindrical configuration and are disposed in concentric relation with one another and with said journal means.
Claim 13
Dependent Claim
44 words
A rotary earth boring drill bit as recited in claim 1, wherein: said bushing retainer means comprises an enlargement formed on said journal means, said enlargement forming a circular thrust support surface positioned for engagement by the inner extremities of said segmented bushing means.
Claim 14
Dependent Claim
81 words
A rotary earth boring drill bit as recited in claim 12, wherein: (a) said journal means forms second thrust shoulder means positioned in spaced relation with said thrust shoulder means and located adjacent the respective one of said cutter support legs; and (b) said segmented bushing means each define circular thrust surface means for engagement with said thrust shoulder means and said second thrust shoulder means to thereby limit axial movement of said segmented bushing means relative to said journal means.
Claim 15
Dependent Claim
36 words
A rotary earth boring drill bit as recited in claim 12, wherein: said thrust shoulder means and said second thrust shoulder means are located at opposite extremities of said bearing surface means of said journal means.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-02-24 | 1989-08-26 | 1990-02-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-02-24 | 1993-08-26 | 1994-02-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-02-24 | 1997-08-26 | 1998-02-25 | $7700.00 | Window Closed / Lapsed |