Expanded – threaded – driven – headed – tool-deformed – or locked-thr – Threaded fastener locked to a discreet structure – Nut – and means to engage substructure on its opposite faces...
Reexamination Certificate
2001-03-19
2002-08-20
Wilson, Neill (Department: 3679)
Expanded, threaded, driven, headed, tool-deformed, or locked-thr
Threaded fastener locked to a discreet structure
Nut, and means to engage substructure on its opposite faces...
C411S187000, C411S411000, C029S402110, C029S402170
Reexamination Certificate
active
06435788
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to thread repair inserts and, in particular, to a thread repair insert and method for repairing threaded holes disposed in materials and for repairing threaded holes disposed in materials in which a crack has propagated therethrough such that the repaired threaded hole may receive a threaded fastener via the insert.
BACKGROUND OF THE INVENTION
Materials often exhibit a variety of different failure mechanisms. On occasion, materials are loaded beyond a tensile strength of the material and the material fractures abruptly and completely. In these circumstances the material is usually non-repairable and must be replaced. However, often materials do not fail in an abrupt complete manner, but rather fail due to fatigue or localized stresses which exceed design criteria, causing cracks to form in the material. Often when these cracks initially form, the material is still functional for its desired purpose. For instance, a reciprocating machine may receive cracks in its structural material and yet continue to operate, albeit at perhaps a lesser efficiency. Cracks thus serve as indicators that a material is being over stressed and yet also provides an opportunity for remedial measures to be taken without requiring entire replacement of the affected material.
Where the crack passes through a preexisting hole, however, such as through a stud hole, or worse, a spark plug hole, a severe problem exists.
Crack repair pins are known in the art which are threaded into holes drilled and tapped in the cracks to prevent cracks from continuing to propagate. U.S. Pat. No. 5,379,505 (issued to the present inventor) provides one example of these crack repair pins. These crack repair pins have been effective in resealing materials such as cast iron casings which require that they maintain a somewhat pressurized environment without allowing fluids to escape therefrom.
In addition, locks are known in the art which can draw cracks together somewhat and extend the life of the material which is cracked. One example of this can be found in the inventor's U.S. Pat. No. 4,662,806.
However, neither of these solutions nor the prior art which applicant is aware address a threaded hole which needs repair to receive a threaded fastener and specifically, the repair of a threaded hole in which a crack has propagated therethrough. Where the threaded hole is a spark plug hole, the problem is quite severe because of the internal pressures within the combustion chamber.
For example, a damaged threaded hole in which a threaded fastener is to be received in needs to be strengthened to a level which effectively allows the threaded fastener to be rigidly retained therein. In addition, the damaged threaded hole may need to be repaired to a level which allows parts to be coupled to one another to effectively provide a seal which will withstand a pressurized environment. Furthermore, the damaged threaded hole may be disposed in a material at a location which requires the walls of the hole to provide means to maintain a somewhat pressurized environment without allowing fluids to escape therefrom.
The following prior art reflects the state of the art of which applicant is aware and is included herewith to discharge applicant's acknowledged duty to disclose relevant prior art. It is stipulated, however, that none of these references teach singly nor render obvious when considered in any conceivable combination the nexus of the instant invention as disclosed in greater detail hereinafter and as particularly claimed.
PATENT NO.
ISSUE DATE
INVENTOR
83,341
October 27, 1868
Foster
154,864
September 8, 1874
Harvey
250,728
December 13, 1881
Harvey
310,462
January 6, 1885
Patten
568,277
September 22, 1896
Rall
678,814
July 16, 1901
Riggs
899,916
September 29, 1908
Smith
1,345,425
July 6, 1920
Wells
1,408,793
March 7, 1922
Anderson, et al.
1,434,870
November 7, 1922
Brubaker, Jr.
1,539,628
May 26, 1925
Bayer
1,543,007
June 23, 1925
Hanson
1,963,542
June 19, 1934
Bergstrom
2,011,484
August 13, 1935
Harman
2,121,692
June 21, 1938
Hays
2,291,162
July 28, 1942
Kirby
2,300,310
October 27, 1942
Poeton
2,361,701
October 31, 1944
Michaels
2,506,233
May 2, 1950
Murphy
2,649,650
August 25, 1953
Javor
2,951,506
September 6, 1960
Diperstein
2,998,645
September 5, 1961
Diperstein
3,066,400
December 4, 1962
Forsythe
3,295,580
January 3, 1967
Waltermire
3,660,233
May 2, 1972
Dalke, et al.
4,074,950
February 21, 1978
Holmes
4,271,554
June 9, 1981
Grenell
4,599,781
July 15, 1986
Diperstein
4,662,806
May 5, 1987
Reed
4,824,279
April 25, 1989
Casazza
4,845,828
July 11, 1989
Reed
4,892,429
January 9, 1990
Giannuzzi
5,033,919
July 23, 1991
Choe
5,379,505
January 10, 1995
Reed
FOREIGN PATENT DOCUMENTS
UK 350,141
June 11, 1931
Arenz
IT 456,481
December 1950
AU 154,074
November 10, 1953
Metalock of Australia
SU 492,389
January 22, 1976
Ivanov Furniture
SU 975,270
November 28, 1982
Mosc Auto Mech Inst.
The other prior art listed above but not specifically described further catalog the prior art of which the applicant is aware. These references diverge even more starkly from the references specifically distinguished above.
SUMMARY OF THE INVENTION
The present invention is distinguished over the known prior art in a multiplicity of ways. For one thing, the present invention provides a thread repair insert which not only repairs threads of a threaded hole but also draws together opposite sides of a crack which may have propagated through the threaded hole. In addition, the thread repair insert according to the present invention provides clamping means which allows the insert to lock into the material to preclude disengagement of the insert from the threaded hole. The clamping means, inter alia, precludes opposite sides of the crack from moving in a direction generally along an axis of the thread repair insert. Furthermore, the thread repair insert strengthens a damaged threaded hole to a level which effectively allows a threaded fastener to be rigidly retained therein and to provide a seal which will withstand a pressurized environment.
In a preferred form, the thread repair insert of the present invention includes a drive head with a means to apply torque thereto, a neck below the head, a shoulder below the neck and a sleeve substantially below the shoulder. Preferably, a thread relief portion is interposed between the shoulder and the sleeve.
The sleeve is provided with an interior thread and an exterior thread. The exterior thread of the sleeve is adapted to be threaded into a hole having a thread pitch which is formed complementally to the exterior thread of the sleeve. The interior threads are preferably adapted to receive a desired standard threaded fastener.
The drive head of the insert can include any of a variety of torque-receiving configurations. For instance, the drive head can have multiple facets dimensioned to be addressed by facets of a wrench. In addition, slots may be formed complementally to a slotted screw driver or other similar structures. Thus, the drive head receives torque and causes the thread repair insert to rotate about a central, long axis thereof.
The neck includes a break-off groove which is interposed between the drive head and the shoulder and preferably defines an area of the thread repair insert having a weakest tensile strength experiencing torsional loads. Thus, when torque is applied through the drive head at greater and greater magnitudes, the thread repair insert fractures at the break-off groove before fracturing in any other location.
The shoulder is interposed between the neck and the exterior threads of the sleeve and includes a cusp exposed at a lower most portion of the shoulder. The cusp is formed by a greater diameter portion and-a lesser diameter portion, with the lesser diameter portion adjacent the exterior threads of the sleeve. Thus, as the thread repair insert is threaded into a complementally formed threaded hole, the cusp of the shoulder abuts against an outer surface of the hole and identifies a point at which the insert can translate n
Kreten Bernhard
Wilson Neill
LandOfFree
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