US 2956462 A
Description (OCR text may contain errors)
Oct. 18, 1960 F. B.'PAUL SPARK-PLUG socxm' WRENCH Filed March 14, 1958 JZQ/IKZZ 2211/ A ORNEY United States Patent SPARK-PLUG SOCKET WRENCH Frank B. Paul, Flint, Mich., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Mar. 14, 1958, Ser. No. 721,517
1 Claim. (Cl. 81-125) This invention relates to spark-plug socket wrenches and more particularly to an insert for a socket wrench to grip and retain a spark plug inserted therein.
In internal combustion engines requiring spark plugs, great difiiculty has been encountered in installing and removing the spark plugs. Most engine constructions provide a deep well for the spark plug, making it ditficult to properly align the plug on installation. Further, engines generally have the spark plugs projecting upwardly, making it diificult to retain a plug in a wrench on installation, and almost impossible to remove the plug without the plug slipping out of the wrench, resulting in damage to the insulator portion or threaded terminal portion of the plug.
To obviate these difficulties, several types of retainers have been made in the past to be inserted in the socket wrench and protect the spark plug. These inserts have met with varying degrees of success and have not completely solved the problems of spark plug installation and removal.
The device in which this invention is embodied comprises an improved nylon sleeve to be inserted in a standard socket wrench. The sleeve provides the proper gripping and retaining functions necessary and gives a longlasting tool. The terminal threads and insulator portion of the spark plugs are protected at all times, whether actually installing or removing the spark plug, or in carrying the spark plug and wrench from place to place. Thus, greater ease in installing and removing the plug is obtained and the plugs are well protected, resulting in more efiicient installations, less operator etlort, and consequent savings in time and money.
In the drawings:
Figure 1 is an elevation of the spark-plug socket wrench and insert with parts broken away and in section and having a spark plug inserted therein, showing the gripping action given the plug by the insert.
Figure 2 is a cross-sectional view of the wrench and insert of Figure 1, showing the insert in its normal position.
Figure 3 is an isometric view of the wrench insert of Figure 1.
Figure 4 is an end view of the socket wrench and insert, taken in the plane of line 4-4 of Figure 2 and looking in the direction of the arrows.
Referring more particularly to the drawings, Figures 1 and 2 best show the insert mounted in the spark-plug socket wrench. The socket wrench is a standard twelve-point socket wrench having a wrench body 12 and twelve triangular projections 13 extending part way up the wrench body. The projections terminate in a shoulder 14 which limits the movement of a spark plug into the wrench. A rectangular opening 16 is provided in the upper end of the wrench body for the insertion of a handle, or some other turning means, and has indentations 18 provided therein. The indentations provide a lock for the handle member inserted in the wrench opening 16.
A nylon sleeve 20 is received in a central bore 22 of the Wrench body 12. The upper half of the insert 24 is of slightly greater outside diameter than the diameter of the bore such that the insert will be slightly compressed and retain itself in the wrench body. The lower half of the insert 26 is of less outside diameter than the diameter of the bore, to provide an annular clearance 28 between the insert and the wall of the bore. A plurality of fingers 30 are formed in the lower half 26 of the sleeve by cutting four slots 32 half way up the length of the insert. The fingers therefor comprise the sleeve material between the slots. Also provided on each finger portion of the insert is an inwardly extending annular projection 34 to grip the insulator portion of a spark plug inserted therein.
In Figure 1, a standard spark plug, indicated generally by the numeral 36, is shown inserted in the spark-plug socket wrench 10 and the sleeve 20. The spark plug consists of a threaded terminal post 38, extending the length of the plug, an insulator portion 40, surrounding the threaded terminal post, a nut portion 42, by which the spark plug is threaded into its place, and a threaded portion 44 which is received in the engine requiring the spark plug. The nut portion 42 is hexagonal in shape and fits within the triangular projections of the socket wrench so that the spark plug may be turned.
The insulator portion 40 of the spark plug extends into the nylon sleeve 20 and is thus protected from the metal walls of the socket wrench. The inwardly extending annular projections 34, formed on the lower ends of the fingers are of less inside diameter than the outer diameter of the insulator portion. When the spark plug is inserted in the wrench and sleeve the insulator portion forces the fingers against the side wall of the bore taking up the clearance space 28 and retaining the spark plug in the wrench. Holding action for the spark plug is therefore provided by the fingers bending and radially expanding into the clearance space 28.
In removing the spark plug from the wrench, or in removing the wrench from an installed spark plug, all that is necessary is a pull in the axial direction to slide the insulator portion out of the sleeve, the fingers returning to the position illustrated in Figure 2.
A spark-plug socket wrench having a plug-receiving bore therein, a nylon sleeve receivable in said bore, one end of said sleeve being of slightly larger outside diameter than said bore for frictionally retaining said sleeve in said bore, a plurality of fingers formed in the other end of said sleeve, the outside diameter of said fingers being less than the diameter of said bore, and inwardly extending projections formed on the inside of said fingers for receiving and retaining a spark plug at its insulator portion, said fingers bending outwardly within said socketwrench bore as a spark plug is inserted therein.
References Cited in the file of this patent 'UNITED STATES PATENTS Re. 23,885 Hubbard Oct. 5, 1954 2,294,193 Merrirnan Aug. 25, 1942 2,304,271 Mern'man et a1 Dec. 8, 1942 2,752,811 Wenchel July 3, 1956 2,778,664 Herbenar Jan. 22, 1957 2,832,245 Burrows Apr. 29, 1958 FOREIGN PATENTS 491,141 Italy Feb. 24, 1954