US2547986A

US2547986A - Method for removal of broken spark plugs

Info

Publication number: US2547986A
Application number: US712612A
Authority: US
Inventors: Henry Leland Van Dermark; Hazel L Van Dermark
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-11-27
Filing date: 1946-11-27
Publication date: 1951-04-10
Anticipated expiration: 1968-04-10

Description

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2 Sheets-Sheet l Filed NOV. 27, 1946 INVENTOR.

Patented Apr. 10, 1951 `UNITED .STATES PATENT OFFICE vraslw Marilou Fon ,REMOVAL F BRKEN SPARK PLUGS Henry Leland Van lerinark, also know-'n as Henry L. Van Dermark, deceased,.late of Sacramento,

C alif., by Hazel L. Van Dernark, executrix,

Medford, Oreg.

Application November 27, 1946, Serial No. 712,612

2 Claims. (Cl. 29-4148) (Granted under the act of March 3, 1883, as

amended il'ril S0, 1928; 370 i). G. 757) The .invention described herein may be ymanufactured and used by or `for the Government for governmental purposes without payment ofA any royalty thereon.

This inventoin relates to a method of removing broken spark plugs from internal combustion engines, particularly those of aircraft. The method is applicable particularly to such engines, the cylinder heads of which are provided with dual ignition from spark plugs located in opposed relation in the head. The method is of Ygeneral application to spark plug ignition engines however, provided that they have the necessary openings for the introduction of tools as will be described.

In the past, an obstinate broken spark plug necessitated removal of the cylinder head. Often, if the head was not removed, broken pieces of metal or porcelain (chips) dropped into the cylinder and created scoring or even worse trouble in the cylinder.

One object of the invention is to enable removal of a broken plug without taking off the `cylinder head.

Another object is to prevent dropping of metal or porcelain chips inside the cylinder.

Another object is to provide a powerful bite for the removal tool into the shell of the broken plug.

Referring now to the drawings:

Fig. 1 is a perspective view in vertical section of an aircraft cylinder head showing a broken plug inits left plug recess.

Fig. 2 is a side elevation or air blast tube tion.

Fig. 3 is a phantom view of the aircraft cylinder head corresponding to Fig. 1 showing the chip removal tool in full view.

Fig. 4 is a fragmentary view corresponding to Fig. 3 showing the drilling tools ready to be applied.

Fig. 5 is a stop drill shown on a larger scale than in the preceding ligure.

Fig. 6 is a plan or end View of the drill jig shown in perspective among the tools shown in Fig. 4.

Fig. 'l is a side elevation of the drill jig.

Fig. 8 is a view corresponding to Fig. 4 with the substitution of removal tools for the drilling tools. Fig. 9 is a side view of aV splined removal tool.

Fig. 10` is an end view of the splined removal tool shown in Fig. 9.

In the figures, I5 is a vertical section of a cylinder head having two spark plug recesses or ports I6 and I 1, these being at' the left and right hand, respectively. Both are fitted with threaded bushof a chip removal tool which forms a related invenings Ilia and Ila, respectively. Within the bushing I6a there is shown a broken spark plug I6.

n The iirst step in the method after knocking `out the 'porcelain core is the insertion through the port Il of the chip removal tool or air blast tube I9 shown in Fig. 2 above and in Fig. 3 locked in place for use. The tool itself comprises a tube 29 having on its outer end a soft rubber gasket 2| and a shoulder 22 to support the gasket. At the opposite or inner end there is a ferrule or connection 23 for the chuck 24 of an air hose 25 (see Fig. 3). A threaded sleeve 26 is adapted to be screwed into the threaded bushing Ila to make a substantially air-tight joint about the tube 20. When the sleeve 26 is tightened after the gasket 2| has been brought against the bottom of the broken plug I8, the tool will occupy the position shown in Fig. 3. As soon as this position is attained, air pressure, say 20 pounds per square inch, is turned on through the hose 25. Chips will then be blown out as they become loosened.

The pressure is maintained as long as there is any likelihood of chips being formed.

Referring now to Fig. 4, 30 is a drill bushing having a body 3| provided with a hexagonal shouldered portion 32 and a threaded extension which is provided with four flutes 34. Four equidistant holes 35 extend longitudinally through the hexagonal portion 32 and the'body 3|. The utes 34 are extensions of the holes 35. The threaded portion 33 ts the threaded bushing I6. In use the jig 30 is screwed into the bushing I6 until it abuts the shell of the broken plug I8. A stop drill 36 which fits holes 35 with a running Iit is now inserted into each hole 35 in turn and the top of the shell I8 is drilled until a stop 31 prevents further entry. An electric drill 38 is used to drive the drill 36.

The result of the above operation is that the spark plug shell I8 is now provided with four internal utes 39 as indicated in Fig. 8. Since the shoulders of the flutes 39 are rough, the interior of shell I8 is hand reamed by means of a reamer 49 and a hand wrench ill. After this operation, a splined tool 42 is inserted so that the splines i3 thereof extend into the flutes 39. Since the splines are sharp on the one edge 43a as shown in Fig. 10, an excellent bite is provided in the direction of reversal of the spark plug threads, i. e., in a direction that will unscrew the plug. The splined tool 42 is thenrotated until the plug |6 is clear of the port I6.

The invention claimed is:

l. The process of removing a spark plug from an engine cylinder which comprises removing the porcelain core of the spark plug, inserting and locking an air blast tube in such a position on the remainder of the plug so that the air blast proceeding from said tube will blow away from the engine cylinder, placing the spark plug to be removed under air pressuer applied through said air blast tube, placing a drill bushing provided with openings over said spark plug, drilling openings in a predetermined pattern in the periphery of the shell of the plug, discontinuing the air pressure after there is no chip formation, applying a tool which fits the openings simultaneously and then unscrewing the plug by rotating the tool.

2. 'I'he process of removing a spark plug from an engine cylinder which comprises knocking out the porcelain core of the spark plug to remove same from the plug shell, inserting and locking in place an air blast tube against the bottom of the plug shell, placing the spark plug shell under air pressure applied through said air blast tube to blow chips in a direction away from the cylinder, placing a drill bushing with openings over said plug shell, drilling the openings in a predeter- 4 mined pattern in the periphery of the shell, discontinuing the air pressure after chip formation ceases, applying a turning tool which fits more than one of the openings drilled into the spark plug shell and then unscrewing the plug by rotation of the tool.

HAZEL L. VAN DERMARK, Execatrix of the Will of Henry Leland Van Dermark, also known as Henry L. Van Denmark, Deceased.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS