US2429920A - Engine failure warning device - Google Patents

Description

Oct. 28, 1947. w, BQURNE JR 2,429,920

ENGINE FAILURE WARNING DEVICE Filed July 11. 1945 f 7 INSULflT/OA/ INVENTOR 8 [Wm/v0 fl. iawr/v-fi BY Wm b. ATT RN EY Patented Oct. 28, 1947 UNITED STATES PATENT OFFICE ENGINE FAILURE WARNING DEVICE Edmund W. Bourne, Jr., Newark, N. Y. Application July 11, 1945, Serial No. 604.400

The invention here disclosed relates to the protection of aircraft engines.

In aircraft operations it is known that most engine failures are attributable to thepresence of metal particles, chips or cuttings in the lubrieating oil.

Special means are usually provided for screening out andfor enabling removal of these metal pieces, but the effectiveness of such devices depends upon the attention given them, routine "inspection and the like, matters which can be and frequently are neglected.

Many engine failures could be prevented and lives and property be saved if it could be known in advance that a situation was developing which might cause engine failure. With notice in time, a pilot can take precautionary steps such as heading for the nearest landing field or, in the case of a multi-engine ship, cutting out the engine where the dangerous condition is imminent, and the like.

The objects of this invention are to provide simple and practical means readily applicable to existing systems which will give the pilot a warning the instant metal cuttings or chips are present in the lubricating oil, in time, so far as possible,

'to enable him to take steps necessary to save the engine and all else depending on the operation of the engine.

These chips or cuttings may be of aluminum, bronze, brass, steel or other metals. It is therefore a particular object of the invention to provide for the detection of any metal chips in the system,

both non-magnetic and magnetic.

Other objects of the invention are to provide warning means such as indicated which will not add objectionable bulk or weight and which when in place will require no servicing or special attention.

Other desirable objects and the novel features by which the purposes of the invention are attained are set forth or will appear in the course of the following specification.

The drawing accompanying and forming part of the specification illustrates a present practical embodiment of the invention. Structure, however, may be modified and changed as regards the immediate illustration, all within the true intent and broad scope of the invention as hereinafter defined and claimed.

Fig, 1 in the drawing is a part sectional and partly diagrammatic view illustrating a present commercial embodiment of the invention.

Fig. 2 is a broken top plan view of the same.

Basically the invention involves the provision '1 Claim. (CL 177-311) of low tension electrodes supported in closely spaced, normally insulated relation in a sump or similar portion of an engine lubricating system where metal chips would likely collect or be (:01- lectible, and the inclusion of such electrodes as portions of a circuit having a warning horn, signal light or the like incorporated therein.

Preferably such electrodes are incorporated in a drain plug adapted to be substituted in place of the conventional oil drain plug and incorporating in its make-up a magnet or magnetic means for attracting magnetic particles to the electrodes. In the construction here shown the electrodes and magnet feature are combined in a single plug structure by making the plug as a hollow body 5 externally screw threaded to fit the conventional ,magnetic electrode 8.

The center electrode is magnetized by a surrounding coil 9 and this winding and the electrode itself are both insulated from the plug body by insulation such as indicated at Ill.

The insulation mentioned may be of Bakelite or other suitable heat and oil resistant material and may be molded in and about the parts, or such parts be otherwise suitably constructed and assembled.

For convenience of manufacture and assembly the center electrode 8 may be made up as an iron core ll having the electrode forming head.8 at one end and having a reduced terminal extension I 2 at the opposite end. The magnetizing winding 9 is shown engaged about the core ll against the head 8 and held in that relation by a washer l3 of insulating material slipped over the terminal pin II.

The outer end of the magnet winding is shown brought out through the insulating washer at It and there engaged or connected with the shell of the plug, 30 as to be grounded when the plug is screwed in the drainage fitting. The other end of the magnet winding is shown as connected at IS with a'termin'al pin I6 extending from the insulating washer l3 parallel to the center terminal [2.

The magnet terminal pins l2 and iii are thus exposed at the end of the plug for engagement by a more or less conventional connector fitting IT on the end of the two-wire cable l8 secured in place by the sleeve I! screwed over the connector sleeve 2|] projecting from the end of the plug body.

In the simplified form of wiring diagram indi- 3 cated, both wires 2| and 22 are connected with one pole of the battery or other current source 23. A resistance 24 is shown interposed in the line 21 to the magnet winding to hold current down to a low value,

Also in this view the warning plug is shown connected in series with the ignition switch 25 of the engine so that the.magnetizing winding will be connected in service only when the engine is on. The normal flow in such case is from the battery through wire 2| to one end of the magnetizing coil, and from the other end of that coil to ground, through the medium of the plug body.

During normal engine operation there is no current flow through wire 22 because the center electrode 8 is insulated from the body of the plug in which it is mounted. Metallic chips or particles, however, bridging the narrow space between electrode 8 and the surrounding rim '5 of the plug, will establish a circuit to ground and by the inclusion of a horn, lamp or other signal means 26 in this line, instant warning of such condition will be given.

The signal 26 may be located in the cockpit or elsewhere and there may be several instead of just one signal. If desired, warning signals now present may be utilized for this additional purpose. Thus, for example, the horn now utilized for signalling condition of the landing gear may be used for this extra function by extending wire 22 to the same.

With current in the signal circuit kept down to a minimum it may be desirable to put a small current sensitive relay in the signal line 22 and control the signal, operating with heavier current, through this relay. While an electromagnet, because of its controllability and greater electromagnetic power, may usually be preferred, it is contemplated that a permanent magnet or magnets may be used in lieu of the electromagnet. In either event the magnetized or magnetic electrode has the effect of pulling down smaller magnetic particles which due to pressure circulation of the oil, might not drop from gravity alone. Hence the magnetic electrode or electrodes is or are highly desirable in those cases where the metal may be in the form of fine particles, such as filings, and which without the magnetic attraction might not bridge across the electrodes soon enough to give effective advance warning. I

The invention is readily applied and at low cost, since the parts arefew and can be relatively inexpensive. The device takes up no extra room and requires no servicing. Connected in on the ignition circuit, it comes into operation automatically and only when needed, that is, when the engine is operating. It is contemplated, however, that this warning system, if desired, may be controlled by separate switching means.

The alarm circuit will be closed by either magnetic or non-magnetic chips or particles and the electrodes can be set so closely together as to activate the alarm even with the smallest sized particles which might start injury. Hence the alarm can be given at the earliest stage of possible breakdown, before the engine really begins to be injured by the chewing up of internal parts.

The invention, in fact, provides a constant check on engine operation, ready instantly to give warning of any change from safe engine operating conditions.

The electrodes being fully exposed to the oil in circulation, will detect the presence of metal practically as soon as it exists. Instead of being plain circular as shown, the electrodes may be given special shapes, the better to collect metal particles and facilitate the short circuiting or bridging eifect across the electrodes. Thus the edge of the center electrode 8 may be toothed or serrated and the inner rim of the plug body 5, similarly shaped, with the teeth partially meshing to shorten the magnetic and electrical gap across the same.

While of particular value for aircraft, it will be evident that the invention is not limited thereto and is applicable to power systems generally,

What is claimed is:

An engine failure advance warning device comprising an electromagnetic screw plug for mounting in the drain opening or other portion of an engine oil circulatory system, said plug consisting of an outer screw shell of metallic material, an electromagnet winding within said screw shell, a magnet core within said winding and having a head at the inner end of the same separated from the rim of the shell by a short annular mag netic gap, oil and heat resistant insulation mechanically and electrically separating said shell and magnet core and sealing said magnetizing winding within the shell, an external wiring ter-- minal on the plug connected with said magnetizing winding for association with an external energizing source, and a second external wiring terminal on said plug insulated from said first terminal and connected with said insulated electromagnet core.

EDMUND W. BOURNE, JR.

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

UNITED STATES PATENTS Number Name Date 570,496 Osborn Nov. 3, 1896 2,252,222 Van Os Aug. 12, 1941 2,317,774 Kick Apr. 27, 1943

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