US1983445A

US1983445A - Stark plug

Info

Publication number: US1983445A
Application number: US679118A
Authority: US
Inventors: Charles G Erny
Original assignee: Individual
Current assignee: Individual
Priority date: 1933-07-05
Filing date: 1933-07-05
Publication date: 1934-12-04
Anticipated expiration: 1951-12-04

Description

C. G. ERNY SPARK PLUG Dec. 4, 1934.

Filed July 5, 1955 Patented Dec. 4, 1934 UNITED STATES PATENT OFFICE SPARK PLUG Charles G. Emy, Philadelphia, Pa.

Application July 5, 1933, Serial No. 679,118

2 Claims. (01. 123-169) This invention relates to improvements in spark plugs of the character disclosed in my copending application Serial Number 659,883, and a principal object of the invention is to provide a spark plug of this character which shall be relatively simple of form and manufacture.

In the attached drawing:

Figure 1 is a side view of a plug made in accordance with my invention;

Fig. 2 is a sectional view of the plug, and

Fig. 3 is a fragmentary sectional view on the line 3--3, Fig. 1.

With reference to the drawing, the plug comprises a casing 1 open at one end for reception of the insulator 2, and having at the opposite end a reduced extension 3 which embraces the firing chamber 4. The insulator 2 is held in place in the usual manner by a gland 5, and carries the terminal 6 which projects into the firing chamber in proximity to a second terminal '7, one end of which is held in the side wall of the said extension and which extends transversely across the outer end of the firing chamber. The extension 3 is provided with screw threads 8 by means of which the plug may be mounted in the cylinder Walls of an internal combustion engine in the usual manner, and these threads are terminated short of the outer end of the extension to provide an unthreaded portion 9 in which are formed the firing port or ports 10, these ports in the present instance being two in number and arranged at diametrically opposite sides of the chamber. The outer end of the chamber is closed by the solid terminal wall 11 of the casing.

Extending diagonally through the wall of the extension from points at the juncture of the threaded and unthreaded portions thereof is a plurality of ports 12 which enter the chamber 4 at a point adjacent the inner end of the chamber. It will be apparent that with this construction the outer ends of the ports 12 are left open when the plug is installed in the internal combustion engine, and thereby aiford ventilation for the inner end of the firing chamber.

The aforedescribed construction reduces the cost of manufacturing plugs of this character to a minimum and at the same time affords a highly efficient device which is characterized by extreme ruggedness and durability under the most exacting conditions, and in a material reduction of carbon and other accretions in the interior of the firing chamber and on the exposed portions of the insulator 2. It will be noted that by providing an unthreaded terminal portion of the extension 3 of sufiicient length to permit the formation in the side walls thereof of firing ports of adequate size, it is possible to form these ports in a single machining operation. By drilling the ports 12 from points at the juncture of the threaded and unthreaded portions of the extension, advantage is taken of the shoulder at the outer terminal end of the threads as a solid abutment for the drills in starting the operation. In order to provide a clearly defined shoulder at this point, it is preferred to machine the unthreaded terminal end of. the extension subsequent to the formation of the screw threads 8.

The lower terminal 7 is inserted in position through a suitably formed opening in the wall of the firing chamber, and may subsequently be permanently secured in position by a simple spotwelding operation. Since the inner end of this terminal element 7 is free, adjustment thereof to regulate the width of the spark gap may be readily accomplished by insertion of a suitable tool through one of the firing ports 10 and by a flexure of the element 'I through the medium of said tool.

While the above described device involves the same principles and effects the same advantageous results as the plug disclosed in my aforesaid pending application, the construction described above effects a material economy in production and thereby constitutes a highly desirable embodiment of my invention.

There may be minor modifications without departure from the invention.

I claim:

1. A spark plug comprising a hollow casing, an insulator in one end of the casing and forming the inner wall of a firing chamber located in the other end of the casing, screw threads on the exterior of the casing terminating short of the outer end of the firing chamber and forming at the terminal end an undercut shoulder on the exterior of the casing, and a plurality of ports initiating in said shoulder and extending obliquely through the wall of the casing to the inner end of the firing chamber.

2. A spark plug comprising a hollow casing, an insulator in one end of the casing and forming the inner wall of a firing chamber located in the other end of the casing, and a shoulder on the outside of the wall of said chamber intermediate the ends of the latter, said shoulder containing the outer end of a port extending diagonally through the side wall to the inner end of the chamber, and said wall having a second port in the outer end thereof communicating with the outer end of the firing chamber.

CHARLES G. ERNY.