US988394A - Spark-plug. - Google Patents

Description

L. R. SPENCER.

SPARK PLUG.

APPLIOATION FILED JAH.14, 1911.

Patented Apr. 4, 1911.

g 4 a 5 f 05% fiww STATES PATENT OFFICE.

149E153. SRENCER, F HARTFORD, CONNECTICUT, ASSIGNOR TO JOHN J. MOINTYRE,

- "F HARTFORD, CONNECTICUT. a

"To till whom "it may concern:

SPARK-PLUG.

. Specification of Letters Patent.

Patented Apr. 4, 1911.-

Applicatidn filed alanuary 14, 1911. Serial No. 602,605.

Be itknown that I, LOUIS SPENCER, a citizen of ;;the United States, residing at Hartford, in the county of Hartford and State ofConnecticut, have invented a new and useful 'Improvementin Spark Plu gs, of

which the fol lowi-ngis a specification.

This anvention relates to the construction of spark plugs for internal combustion engines, f

The objeot o'f the invention is to provide a relatively small, simple and cheap plug which "is efli'cient, durable, and can be readily cleaned and adjusted.

d' g-ure l of the accon'rpanying drawings 'Hshows aside elevation of a plug which enibodies the invention. Fig. 2 shows a central vertical section of the same. Fig. 3 shows J-a bottom view oftheplug.

Theplug i l' histrated has a hollow cy1indries-1 body 1, which is preferably made of steel and provided with an exteriorly threaded hub 2, that is designed to be screwed into'the' engine cylinder casing.

' employment of any packing.

Theupper edge of the body has an internally beveled surface 3, and near this edge in the interior the body ,is provided with a thread; Screwed into this interior thread in the body is the threaded end of a thimble 4. The thimble is desirably made of soft brass and has an external tapering surface 5, which when the thimble and body are screwed together, is adapted to seat against the internalt-apering surface 3 so as to form ati ht joint between the parts, without the As a result of this construction, the body and thimble are always fastened together in the same relation to each other, for there is no packing "between the two, which would have a tendency to yield, and thus vary the relation of the parts, and which would be liable to burn out or become ineflicient under the influence of the heat to which a spark plug body is subjected.

In the lower end of the hub 2 of the body is an opening 6, and spanning this opening is-a conducting bow 7 provided with a cen an terminal point 8.- The opening through the thiinble tapers or contracts from the bottom upwardly, and driven into this opening from the underside is a porcelain bushing 9. This bushing is larger at the bottom than atthe top, the taper however being slight, so that the bushing may be driven tightly into the 'thi-mble. As a result of tapering these parts in this manner, the pressure, incident to explosions of gas in the cylinder, tends to drive the bushing upwardly into a more contracted part of the opening in the thimbleand thus expand the soft thin'lbleoutwardly and cause the threaded and tapered joints between the lower end of the thiinble and the upper end of the body to more tightly closed. l I

Extending through the central opening in thethhnble is a rod 10. The lowereud of this rod hash 'termiiialvpoint- 11, while the upper'end is provided with a wire clumping piece 12. A portion of the rod 10 is threaded, and turning on the threaded part of the rod below the bushing is a nut 13,

and turning on the threaded part abovethe bushing is a nut 14. Mica washers 15, which are'larger in diameter than the bushing, are desirablyvused between the upper nut 14 and the to of the bushing. The nuts permit the ro to ,be readily adjusted for the purpose of varying the spark gap between the terminal points, when it is desirable or when it is necessaryto file down one of the points in order to re-forin the end of the terminal. The nuts'also hold the rod firmly in position. The mica washers at the upper end of the bushing being larger in diameter than the diameter of the bushing, allow the porcelain to be much shorter than otherwise would be the case, for the washers lengthen the distance and make abreak in the continuity of the insulating surface be tween the upper nut 14 on the rod-10 and the upper end of the thimble. Thewashers also form a protection for the upper end of the "fragile porcelain bushing, and prevent it from being chipped or cracked by the tightening of the nuts, and they also pack the opening through which the'rod extends so that no gass can escape and thus tend to lower the compression in the cylinder into which the plug is screwed. \Vith this construction the porcelain may be shortened without decreasing the effectiveness of the insulation, andthus the strength and durability of the plug as a whole is increased, and furthermore, it does not take up as much space, for it does not project as far from the cylinder into which it is screwed as would otherwise be the case. When the central f contact carried by the porcelain bushing'is adjusted, if the thimble and bushmore firmly ble andcause same position and the there is no compressible packing between inglare removed for cleaning the points, the,

parts can tie screwed back to exactly the oints made tight, as

terminal is well separated from the body I and is so protected thatit is not likely to be sooted by the explosions and become ineificient or permit localities other The invention claimed is:

1. A spark plug having a with, an exterior thread at one end and an internal bevel and'an interior thread at the other-end, a conducting bow spanning the thread adapted to fit the upper end-of the :with an exterior 'nuts on the rod aboveand below exteriorly threaded end of the body, a thimble with an. external bevel and exterior body, said thi'mble having a tapering. opening which contracts from the lower end upward, an insulating-bushing that is largest at its lower end driven upwardly into the tapering opening in the thnnble, a conducting rod extending through the bushing, and the bushing for adjusting the parts with relation toeach other and the lower end' of the said. rod with relation to the bow at the lower end of the body.

'2. A spark plug having a body provided thread at one end. and an external bevel and an interior thread at the other end, a conducting bow spanning the I exteriorly' threaded end of the body, a thim on the rod above and be ow leakage of current from 3. A spark than at the terminal points.

body provided I teriorly threaded opening in the thimble, tending through the bushing, nuts on g the rod above and below the bushing for adjustble with an external bevel and exterior thread adapted to fit the upper end of the body, said thimble having atapering opening which contracts from the lower. end upward, an insulating bushing'that is largest at its lower end driven upwardly into the tapering opening in the thnnble', a conducting rod extending throu h the bushing, nuts the bushing for adjusting the parts with relation to each other and the lower relation to the bow at the lower end ofthe body, and mica washers which arelarger in end of the" said rod with Y diameter than the diameter of the bushing located between the upper nut on the 1:0 and the upper end ofthebushingj.

with an exterior other end, a conducting bow spanning the exend of the body, a thinfible with an external bevel and exterior thread adapted to fit the upper end of the body, said. thimble having a tapering opening which contracts from the lower end upward, an insulating bushing that is largest at its lower end driven upwardly into the tapering a conducting rod exing the parts with relation to each other and the lower end of the said'rod with relation to t,he. bow at the lower end of the body, a

plug having a body'pro' 'ded thread atone end and aninternal bevel and an interior thread at the terminal point projecting upwardly from the center of the bow at the lower end of the body, and a terminal point projectmgdownwardly'from the lower end of the rod.

' LOUIS R. SPENCER. lVitnesses i JosnrHmnM. Srnnmrrnn, H. R. VVILLIAMs.

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