In re Crawford

250 F.2d 370, 45 C.C.P.A. 750, 116 U.S.P.Q. (BNA) 149, 1957 CCPA LEXIS 120
CourtCourt of Customs and Patent Appeals
DecidedDecember 13, 1957
DocketNo. 6305
StatusPublished
Cited by5 cases

This text of 250 F.2d 370 (In re Crawford) is published on Counsel Stack Legal Research, covering Court of Customs and Patent Appeals primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
In re Crawford, 250 F.2d 370, 45 C.C.P.A. 750, 116 U.S.P.Q. (BNA) 149, 1957 CCPA LEXIS 120 (ccpa 1957).

Opinion

O’Connell, Judge,

delivered the opinion of the court:

This is an appeal from the decision of the Board of Appeals of the United States Patent Office sustaining the primary examiner’s rejection, of claims 24,25, 27 and 28 of appellant’s application No. 388,175 for a patent on an earth boring method and apparatus. Claims 30, 31, 39 and 40 were originally included in the appeal, but the appeal as to those claims has been withdrawn. Fifteen claims of the application have been allowed.

Claims 24 and 27 which are representative of the appealed claims are as follows:

24. An explosive perforating unit, comprising, a hollow casing composed of imperforate glass material and hermetically sealed, a body of a detonating explosive enclosed within said casing, said body having a generally conical hollow in one end thereof spaced from one end wall of said casing and said body having its other end in contact with the opposite end wall of said casing, and a thin metallic liner having a shape corresponding to said hollow seated therein, said glass material transmitting detonating shock at high order from the exterior of said casing through the glass material of said opposite end wall directly to said body to obtain substantially complete high order detonation of said body to produce an effective perforating jet and with substantially complete disintegration of said casing.
27. An explosive unit, comprising, a hollow casing composed of glass material and sealed, a body of an explosive enclosed within said casing, said body having a generally conical hollow in one end thereof spaced from one end wall of said casing and said body having its other end in contact with the opposite end wall of said casing, and a thin metallic liner having a shape corresponding to said hollow seated therein.

[751]*751The references relied on by the Patent Office tribunals are:

Beach, 82,586, September 29,1868.
Miller, 494,877, April 4,1893.
Bolton, 2,265,982, December 16,1941.
Whitman, 2,300,823, November 3,1942.
Mohaupt, 2,407,093, Setpember 3,1946.
Muskat et al., 2,494,256, January 10,1950.
Sweetman, 2,629,325, February 24,1953.
“The Shaped Charge” by Yolta Torrey, published in “The Explosives Engineer,” July-August, 1945.

Appellant’s application relates to earth boring apparatus of the type in which a hollow drill bit is rotated at the end of a string of pipe. When a difficult earth formation is encountered, appellant raises the drill bit a short distance above the bottom of the bore and lowers an explosive perforating unit through the pipe string and drill bit ■until its rests on the bottom of the bore. The explosive charge is then detonated thus blasting out, or at least improving the drillability of, some of the material in the formation to be drilled. The appealed claims are concerned only with the particular type of explosive perforating unit and the process which results from its use, and it is unnecessary to consider further the other features of appellant’s invention.

Appellant’s application discloses two generally similar forms of explosive perforating unit, each of which comprises an elongated cylindrical body made of glass or similar material and having a cylindrical chamber which occupies approximately the lower half of the body and which contains the explosive charge. The upper portion of the body may be solid or hollow or may comprise a central core extending through an annular chamber. Such a core may carry electrical wires connecting with a detonator located at the top of the explosive charge, or it may take the form of a percussion cap extending to the top of the body and adapted to be actuated by a “go-devil” dropped down the pipe string.

The lower end of the explosive charge terminates above the bottom of the chamber in which it is located and is formed with a conical hollow which flares downwardly, and in which is seated a metal liner corresponding in shape with that of the hollow. When the charge is detonated the hollow tends to direct the force of the explosion axially against the bottom of the bore.

The patent to Beach discloses a torpedo for oil wells comprising a cylindrical shell of glass or similar material containing an explosive charge. It is stated in the patent • specification that the shell is broken, by the explosion, into fine particles which will not choke the well or cause derangement of the pumping mechanism.

[752]*752The patent to Mohaupt discloses an apparatus for punching sheet material, comprising a cylindrical casing adapted to be placed upon the material to be punched. The upper part of the casing contains an explosive charge which is supported above the bottom of the casing by a cutter member. When the charge is exploded the cutter member is driven downwardly through the bottom of the casing and punches a hole in the sheet material.

The Muskat et al. patent and the Torrey publication disclose the shaping of explosive charges by providing a conical hollow, covered by a similarly shaped metal liner, in the end of the charge toward which the force of the explosion is to be directed, and Torrey explains that such an arrangement greatly increases the explosive force in a direction axial with respect to the hollow. He also states that when the explosion is to be used to form a cavity in a surface, the charge should be spaced from the surface in order to obtain the maximum effect.

The Sweetman patent relates to a jet type perforating unit for use in oil wells. It discloses a glass casing containing an explosive charge having a conical hollow in one end covered by a similarly shaped liner. The end of the charge which contains the hollow is spaced from one end wall of the casing. The other end of the charge is in contact with the opposite end wall of the container, and the charge at that point is made more sensitive than elsewhere, either by packing it to a different density or by using a different type of material. The charge is detonated by a force applied externally of the casing and transmitted through the glass wall of the casing to the more sensitive portion of the charge. The patent specification states that it is important that the thickness of the casing wall at the point where the detonating force is applied must be such as to permit effective transmission of that force, and that such thickness should ordinarily be between one-eighth and one-fourth of an inch.

The patents to Miller, Bolton, and Whitman were not relied on in the rejection of the claims here on appeal, and need not be considered.

Appealed claims 24 and 25, which were copied by appellant from the Sweetman patent, were rejected on the ground that they are not supported by the disclosure of appellant’s application. It was held by the examiner and the board that appellant’s disclosure does not satisfy the following requirement of those claims: “said glass material transmitting detonating shock at high order from the exterior of said casing through the glass material of said opposite end wall directly to said body [of detonating explosive] to obtain substantially complete high order detonation.”

[753]

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Related

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337 F.2d 664 (Customs and Patent Appeals, 1964)
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Bluebook (online)
250 F.2d 370, 45 C.C.P.A. 750, 116 U.S.P.Q. (BNA) 149, 1957 CCPA LEXIS 120, Counsel Stack Legal Research, https://law.counselstack.com/opinion/in-re-crawford-ccpa-1957.