US 2060881 A
Description (OCR text may contain errors)
Nov. 17, 1936. O c. U w n' 2,060,881
MAGNETO Filed June 10, 1935 Z JNVENTOR.
OWEN C. Lmmwawk'" ATTORNEY.
Patented Nov. 17, 1936 UNITED STATES PATENT OFFICE MAGNETO Application June 10, 1935, Serial No. 25,804
This invention relates to magnetos and more particularly to a magneto designed especially for use with an outboard motor.
The invention is particularly applicable to an air-cooled outboard motor wherein the flywheel is provided with blades to blow air over the engine to effect the cooling thereof.
In the prior art of which I am aware, represented by such patents as Schreil 1,765,454; 'Cruickshank 1,734,999; Irgens 1,899,965; and Schreil 1,734,350, the primary and secondary coils, together with the core pieces and breaker mechanism are carried upon the flywheel of the engine. In designing an air-cooled engine, it is necessary to employ the space within the periphery of the flywheel to carry the blades of the fan. It is therefore impractical to employ structures similar to those illustrated by the patents noted above.
An object of this invention is therefore to provide a bladed flywheel wherein a portion of the outer periphery of the flywheel carries the field magnet, and the primary and secondary coils, together with the core pieces, are mounted in closeproximity to the outer periphery of the flywheel.
Another object of the invention is to provide an insulated flywheel, wherein insulating material is employed to insulate the field magnet from the remainder of the flywheel.
A still further object of the invention is to provide a magneto in which the timing contacts are normally open throughout the major portion of the cycle of operation, and are only momentarily closed to produce the ignition spark, thereby eiiecting a saving in the amount of current used;
Another object of the invention is to provide a -magneto, wherein simple means are employed to advance and retard the spark, and means are provided to assure a spark of uniform intensity regardless of the timer setting or the speed of rotation of the engine.
A further object of the invention is to provide a combined flywheel, insulated magnet and cooling fan.
Another object is to produce a simple and inexpensive magneto designed especially for use with air-cooled engines.
Further objects and advantages of this invention will appear inthe following description considered in connection with the accompanying drawing submitted for purposes of illustration only, and not intended to define the scope ofthe invention, reference being had for that purpose to the subjoined claims.
In the drawing, wherein similar reference characters refer to similar parts throughout the several views:
Figure 1 is an elevational view partly in section of an outboard motor equipped with a device of the present invention;
Figure 2 is a planview of the bladed flywheel and the field magnet of the magneto;
Figure 3 is a view taken on the lines 3-3 of Figure 2; and
Figure 4 is a view taken on the lines 4-4 of Figure 3.
Referring more particularly to Figure 1, there is shown an outboard motor having a crankcase l0, fitted with a cylinder 12. A crankshaft l4 projects through the upper end of the crankcase I0, and is fitted with a flywheel l6 having blades is extending from the hub portion, 20 to a circular rim 22 of the flywheel.
Power is transmitted from the engine through.
a streamlined housing 24 to rotate a propeller 26 to drive a boat, a portion of which is represented at 28.
A circular field magnet 30, made of soft iron or other suitable material, is fitted to the circular rim 22 and is insulated therefrom by any suitable insulating material 32. The field magnet 30, being made of relatively heavy material, forms the greater portion of the mass of the flywheel to supply the desired inertia for the smooth operation of the engine.
An insulator 34 of suitable weight is interposed in the'gap of field magnet 30 (Figures 2 and 4) to balance the flywheel. In operation lines of magnetic flux flow across the small air gap between the core pieces 36 and the field magnet 30 to energize the primary and secondary windings l0 and 42 respectively, carried by the core 38, to increase the potential of the current. A current of sufficient intensity to cause a spark to jump between the points of a spark plug to fire the combustible charge compressed in the cylinder I2 is then produced.
The core pieces 36, core 38, and primary and secondary windings l0 and 42 respectively are carried by a spider or rack 46, adapted to hold the core pieces 36 in close proximity to the field magnet 30 to avoid losses of intensity of the current due to a large air gap. Manual means, including the lever 48, are provided to advance or retard the spark, that is, the instant at which the spark will be produced in the cylinder I2 with reference to the 'position of the piston or crankshaft may be varied at will to produce the most satisfactory operation of the engine.
In the event that the insulating material :1,
interposed in the field magnet 30, is not of the ame specific gravity as the magnet 30, the flywheel may be balanced in any convenient manner, as by removing or adding thereto some of the metal from a portion of the flywheel in a known manner.
If desired, the fan blades IS, the hub 20, and the circular rim 22 may be made of insulating material such as bakelite, phenol resin or any other suitable material to avoid the necessity of interposing insulating material between the field magnet 30 and the circular rim 22. Also, if desired, the fan blades, hub, and rim may be formed with a metal base, having a coating of rubber sprayed or baked thereon to effectively insulate the field magnet and to avoid shortcircuit losses.
The operation of this device is as follows. when the engine is running the blades ll of the rotating flywheel I6 induce a current of air to flow over the cylinder l2 and the crankcase III of the engine to prevent the engine from rising above a safe operating temperature.
Each time the Opening of the magnet passes the core pieces 36'the lines of magnetic flux flow through the primary winding 40 to increase the potential in the circuit. The secondary winding 42 is then energized by the closing of the connecting circuit, whereupon a spark is produced in the spark plug in the cylinder II of the engine to ignite the compressed combustible charge to initiate the power stroke of the engine.
While the invention has been described with particular reference to a preferred embodiment, it is not intended to limit the scope of the invention to the features discussed, nor otherwise than by' the terms of the following claims.
1. In a flywheel magneto a flywheel comprising a metallic hub member, a rim including an insulated member forming a permanent magnet, a bladed fan of bakelite material interconnecting the hub and rim, a circumferentially movable core member positioned adjacent the rim,
primary and secondary windings on the core member, and manually operable means to move said core member circumi'erentially.
. 2. A flywheel magneto having a flywheel comprising a hub member of a phenolic condensae tion product, a metallic rim including an insulated member forming a permanent magnet, a
bladed fan of a phenolic condensation product of bakelite material positioned within the rim, a circumferentially movable core member positioned adjacent the rim, primary and secondary windings on the core member, and manually operable means to move said core member circumferentially.
3. As an article of manufacture, a flywheel for a flywheel magneto, comprising a metallic rim having an insulated member therein to form a permanent magnet, a hub and abladed fan formed of bakelite positioned within the metallic rim.
OWEN C. LINTHWAITE.