US 3693148 A
An engine timing light adapted to be detachably inserted in the distributor cap opening for a spark plug wire, and also adapted to detachably receive the spark plug wire which normally fits within the distributor cap opening. The timing light flashes on when the distributor points open, indicating when the spark plug would have been fired. The light enables setting of the time at which the points open in relation to travel of the associated piston, without having to open the distributor.
Description (OCR text may contain errors)
" United States Patent Pittman ENGINE TIMING LIGHT  Inventor: James E. Pittman, 2761 Adriatic Ave., Long Beach, Calif. 90810  Filed: Feb. 11, 1971  Appl. No.: 114,563
 US. Cl ..340/52 R, 73/116, 324/15  Int. Cl ..F02p 17/00  Field of Search...340/52 R, 256; 73/116, 119 R; 307/10 R; 317/96, 97; 123/198 DA; 116/124;
 References Cited UNITED STATES PATENTS 2,067,618 4/1937 Cooper ..324/17 2,355,211 8/1944 Erickson ..340/52 R 2,441,782 5/1948 Wass ct a1. ..340/52 R [151 3,693,148 51 Sept. 19, 1972 2,517,302 8/1950 Graves ..340/52R 2,648,816 8/1953 Schuch ..324/15 Primary Examiner-John W. Caldwell Assistant Examiner-G1en R. Swann, I11 Attorney--Fulwider, Patton, Rieber, Lee & Utecht [5 7] ABSTRACT An engine timing light adapted to be detachably inserted in the distributor cap opening for a spark plug wire, and also adapted to detachably receive the spark plug wire which normallyfits within the distributor cap opening. The timing light flashes on when the distributor points open, indicating when the spark plug would have been fired. The light enables setting of the time at which the points open in relation to travel of the associated piston, without having to open the distributor.
4 Claims, 3 Drawing Figures PATENTEDSEP 19 I972 FIG.2
INVENTOR. ZMEJ 1 .P/rr/vmv ea, M
'flrr ENEKS ENGINE TIMING LIGHT BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine timing light and more particularly to an engine timing light adapted to indicate when the distributor points have opened.
2. Description of the Prior Art Many devices for timing the ignition system of an automotive engine or the like require removal of the distributor cap to establish the point at which the distributor points opens. For this purpose various prior art timing devices also require attachment of leads by connecting clips or the like to the spark plug and also to the distributor cap openings or sockets. The connecting clips usually are undesirably exposed, are bothersome to attach and detach properly, and sometimes confuse the user as to their proper location and attachment points.
SUMMARY According to the present invention a compact, unitary engine timing light is provided which is rugged in construction and easy to use. No special wiring or assembly procedure is necessary to use it. It is simply plugged in to the distributor cap opening within which a spark plug wire is usually disposed, and that wire is then, in turn, plugged in to an opening in the timing device.
The timing light comprises a casing having a test fitting adapted to fit within the distributor cap opening, the casing including a socket for receiving the spark plug wire fitting which was removed from the distributor. The casing includes a neon bulb which flashes when the distributor points open, thereby giving an indication of the time of a firing of the associated spark plug. In a preferred method of use the engine mechanic or other user simply rotates the engine crankshaft until the 1 cylinder is rising on its compression stroke. Rotation of the crank-shaft is continued until the timing marks on the engine and the flywheel are properly aligned. This is the point at which the spark plug should fire. The distributor body is then rotated until the timing light comes on, at which point the mechanic knows that the 1 cylinder will fire at the proper time.
Other objects and features of the invention will become apparent from consideration of the following description taken in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of an engine timing light according to the present invention;
FIG. 2 is a view taken along the line 2-2 of FIG. 1; and' FIG. 3 is an enlarged perspective view of an electrical distributor for an engine, illustrating the manner of mounting the present timing light to the distributor for reception of the spark plug wire fitting.
DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, there is illustrated an engine timing light adapted to be mounted upon a distributor cap 12 of a usual and conventional electrical distributor 14 for an internal combustion engine.
As is well known, the ignition of the fuel-air charge in the cylinders of the usual four cycle internal combustion engine is correlated with the location of the 1 piston in a position a few degrees ahead of its top dead center position as it comes up on its compression stroke. The exact piston position is most often indicated by timing marks placed by the manufacturer on a portion of the engine which moves in correspondence with the piston movement. The flywheel is usually employed for this purpose, and a reference mark is also applied to an adjacent stationary part of the engine. When the two marks are in alignment the engine mechanic knows that the l spark plug should just fire. If it fires at the proper time the other cylinders will also be properly timed.
Once the timing marks are aligned, the engine mechanic must next adjust the electrical system to be sure that the l spark plug will fire at this time.
The present timing light 10 is concerned with the timing of engines which use a distributor 14 having internal distributor points which open at intervals, each opening causing energization of an electrical circuit through the engine ignition system and to one of the spark plugs. This causes a spark to jump the plug gap and ignite the cylinder fuel-air charge.
The usual distributor is rotatable a limited number of degrees in either direction so as to move the distributor points as a unit relative to the distributor shaft cam and thereby set the time of opening of the points relative to the travel of the associated piston. The distributor cap 12 is rotated relative to the distributor 14 by first unscrewing a machine screw 16, rotating the cap 12, and then retightening the screw 16.
The distributor 14 illustrated by way of example mounts six spark plug wires 18 for an associated six cylinder four cycle, internal combustion engine (not shown). Each of the wires 18 includes usual electrical insulation overlying an inner lead wire which is electrically connected to an electrically conductive spark plug wire fitting 20.
Each fitting 20 is somewhat resilient in character so as to be able to be press fitted within one of the complemental distributor cap sockets or openings provided in the distributor cap 12. A weather-proof cap 22 made of rubber or the like is provided on each of the wires 18 to overlie the distributor cap opening when the associated fitting 20 is inserted within the opening. As will be seen, by removing from the distributor cap 12 the plug wire fitting 20 for the 1 cylinder, and inserting the timing light 10 in its place, and thereafter inserting the removed spark plug wire 18 in the engine timing light 10, the light 10 will indicate when. the would have been fired.
In this regard, the timing light 10 comprises, generally, an electrically non-conductive casing 24 made of plastic material or the like. The casing 24 includes an annular seat 26 upon which is press fitted or otherwise removably secured a transparent cap or cover 28 which overlies a neon bulb constituting an indicator light 30. The base of the light 30 is threaded so that it can be screwed into a complementally threaded, electrically conductive sleeve 32 which is embedded in the plastic material of which the casing 24 is conl spark plugstituted. The electrical circuit through the light 30 is carried through the metal shank 34 of the light30 to the sleeve 32 and then, through an electrical lead 36 to a terminal portion of an electrically conductive, cylindrical member or sleeve constituting a socket 38 for the spark plug wire fitting 20. The other side of the electrical circuit through the indicator light 30 is connected through a terminal 40 at the base of the light shank 34 to the upper surface or terminal portion 42 of a vertically elongated test fitting 44. Except for the larger diameter terminal portion 42, the test fitting is cylindrical and of generally uniform cross section throughout its length. The test fitting 44 is electrically conductive and includes an elongated end slot 46 which enables the test fitting 44 to be press fitted within the complemental distributor cap opening. That is, the end portion of the test fitting 44 is compressed slightly to fit within the distributor cap opening, and the tendency of the slot 46 to open exerts a bias to maintain the test fitting 44 in position.
As is well known to those skilled in the art, when the distributor points (not shown) within the distributor cap 12 open, a circuit is energized which includes the spark plug fitting 20, the associated l spark plug wire, and the l spark plug. This fires the charge in the 1 cylinder. With the timing light in position, this circuit is completed through the test fitting 44, the filament of the light 30, the lead 36, the socket 38, the spark plug wire fitting 20, and the spark plug wire 18 to the spark plug. Completion of this circuit causes the light 30 to come on and thereby give the engine mechanic an indication of the opening of the distributor points.
In use, the engine mechanic rotates the engine crankshaft until the timing marks are aligned, as previously mentioned, and if the indicator light 30 just comes on at this time the mechanic knows that the point of firing of the 1 cylinder is correct. On the other hand, if the light has come on prematurely, or has not yet come on, the mechanic loosens the screw 16, and rotates the distributor 14 in the proper direction relative to the distributor cam shaft so that the indicator light 30 just comes on at the time the timing marks are aligned. The screw 16 is retightened, and the engine will then be properly timed. The procedure is completed by removing the timing light 10 from the distributor cap 12, removing the spark plug wire 18 from the engine timing light socket 38, and reinserting the spark plug wire in its opening in the distributor cap From the-foregoing it will be apparent that utilization of the present engine timing light 10 permits the opening of the points to be timed relative to travel of the associated piston without any necessity for access to the interior of the distributor. Moreover, only the unitary structure of the light 10 is involved in timing the engine. There are no additional leads, wires, or connecting clips involved. The user simply interposes the light between the distributor cap opening and the spark plug wire which normally fits into that opening. Once the timing is completed, the wire is reinserted in its proper position and the timing light 10 is removed for future use.
Various modifications and changes may be made with regard to the foregoing detailed description witl'g i t cliepartmg from the spirit of the invention.
1. An engine timing light comprising:
an electrically non-conductive casing including a seat, an elongated socket adapted to detachably receive the spark plug wire fitting located at the distributor cap end of a spark plug wire, said casing further including an elongated test fitting adapted for detachable insertion into the distributor cap opening within which said spark plug wire fitting is normally disposed, said socket having a terminal portion for electrical connection with said spark plug wire fitting, said test fitting having a terminal portion for electrical connection with the lead terminal of said distributor cap opening;
an indicator light on said casing and electrically connected to said socket terminal portion and said test fitting terminal portion, respectively; and
a cover mounted on said seat and enabling observation of said indicator light.
2. An engine timing light according to claim 1 wherein the longitudinal axis of said socket is disposed upwardly and outwardly relative to the longitudinal axis of said test fitting to facilitate insertion of a spark plug wire fitting into said socket.
3. An engine timing light according to claim 1 wherein the interior walls of said socket are dimensioned to closely receive and frictionally retain the exterior walls of said test fitting.
4. An engine timing light comprising:
an electrically non-conductive casing, an elongated socket adapted to detachably receive the spark plug wire fitting located at the distributor cap end of a spark plug wire, said casing further including an elongated test fitting adapted for detachable insertion into the distributor cap opening within which said spark plug wire fitting is normally disposed, said socket having a terminal portion for electrical connection with said spark plug wire fitting, said test fitting having a terminal portion for electrical connection with the lead terminal of said distributor cap opening; and
an indicator light on said casing and electrically connected to said socket terminal portion and said test fitting terminal portion, respectively.
UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 Da d September 19, 1972 Invent James E. Pitt an It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
In the references cited change "2,067,618" to 2 O76 618 Signed and sealed this 13th day of March 1973.
EDWARD M.FLETCHER,JR. ROBERT OOTTSCHALK Attest ing Officer Commissioner of Patents FORM PO-105O (10-69) USCOMM-DC GOING-P69 1* us. GOVERNMENT PRINTING OFFICE: 1969 o-ass-zam