US2159256A - Portable internal combustion engine - Google Patents

Description

May 23, 1939. D. R. CLARKE PORTABLE INTERNAL COMBUSTION ENGINE Filed Aug. 30. 1937 2 Sheets-Sheet l INV EN TOR lll Il I :sul 5 lun:

DOUGLAS R.CLR K E BY ATTORNEYS May 23, 1939. D. R. CLARKE PORTABLE INTERNAL COMBUSTION ENGINE Filed Aug. 50, 1937 2 Sheets-Sheet INVENTOR DOUGLAS R.CLARK MMM Patented May 23, 1939 UNITED STATES PATENT OFFICE PORTABLE INTERNAL COMBUSTION ENGINE 8 Claims.

This invention relates generally to internal combustion engines of the type employed for marine purposes and has particular reference to portable or outboard motors of the general char- 5 acter disclosed in my copending application Serial No. 83,745, led June 5, 1936.

It is one of the principal objects of this invention to provide a light, compact motor composed of a relatively few simple parts capable of l being inexpensively manufactured and readily assembled.

Another object of the present invention consists in the provision of a mounting for the motor rendering it possible to readily swing the motor 15 to a position wherein the propeller is clear of the water and having means effective to rigidly hold the motor in this position while being cranked. In accordance with this invention, the engine is started by turning the crankshaft directly and 20 the mounting not only effectively prevents up and down movement of the engine during the cranking operation, but also prevents oscillation of the engine about the steering axis.

Another advantageous feature of the present 25 invention resides in the provision of a mounting of the character set forth equipped with means for insulating the engine from the boat and for effectively absorbing vibrations instituted in the l engine so that transfer of these vibrations to the 3 boat is reduced to the minimum.

A further object of this invention resides in the means provided herein for conducting fuel mixture to the combustion chamber of the engine andfor regulating the flow of fuel mixture admitted to said chamber.

Still another object of the invention consists in the simple and effective ignition means provided for igniting the fuel mixture in the combustion chamber.

In addition to the foregoing, the present invention contemplates a portable engine of the type specified having provision rendering it possible to transport the motor without draining the fuel 45 from the fuel supply tank.

The foregoing, as well as other objects will be made more apparent, especially when considered in connection with the accompanying drawings, wherein:

50 Figure 1 is a sectional view through an engine constructed in accordance with this invention;

Figure 2 is a side elevational view illustrating in full lines the position of the engine during the cranking operation and showing' in broken lines 55 the normal location of the engine;

Figure 3 is a rear elevation of the engine shown in Figure 1;

Figure 4 is a front elevation of the engine;

Figure 5 is a top plan view of the engine;

Figure 6 is a sectional view taken substantially 5 on the plane indicated by the line 6 6 of Figure 1;

Figure 7 is a sectional view taken substantially on the plane indicated by the line 1-1 of Figure 1; 10

Figure 8 is a sectional View taken substantially on the plane indicated by the line 8-8 of Figure 1;

Figure 9 is a group perspective View of the several parts of the mounting; 16

Figure 10 is a cross sectional view taken substantially on the plane indicated by the line ill-I0 of Figure 1;

Figure 11 is a sectional view taken substantially on the plane indicated by the line Il-II of Figure 3; and

Figure 12 is a cross sectional view taken substantially on the plane indicated by the line |2-i2 of Figure 1.

For the purpose of illustrating the present invention, I have selected a portable marine engine of the single cylinder type operating on the two cycle principle and having provision for removably clamping the same to a suitable boat. It will be observed that the engine is similar in principle to the one set forth in my above identified copending application in that the cylinder of the engine is supported below the water level during operation in order that the same will be effectively cooled without the necessity of employing a circulating system including water jackets and in that the propeller, which is mounted directly on the crankshaft, is turned directly to crank the engine when the latter is supported in its tilted position shown by the full lines in Figure 2. It will, of course, be understood that the elimination of the Water jackets appreciably decreases the Weight of the engine and, consequently, the cost of manufacture thereof. It will also be observed that by cranking the engine in the tilted position thereof shown in Figure 2, it is not necessary to overcome the resistance offered by the Water to rotation of the propeller and, as a result, starting of the engine is effected with less effort.

In detail, the engine proper comprises three castings, designated in Figures 1, 3, and 4 by the reference characters I5, i6, and Il. The intermediate casting I6 is detachably secured to the top section i5 by means of the studs I8 and is 55 similarly secured to the bottom section I1 by means of the studs I8. As a result, a unitary construction is provided capable of being readily as,

sembled and disassembled.

Upon reference to Figure 1, it will be noted that the casting I5 ls fashioned to form a fuel supply tank 28 having a top wall 2I forming a support for the ignition coil 22 and carburetor 23. 'I'he intermediate casting I6 1s fashioned to provide a cylinder 24 at the lower end thereof and the bottom casting I1 is fashioned to support a crankshaft 25.

Referring again to Figure 1, it will be noted that fuel conduits 28 and 21 are respectively cast integral with the top and intermediate castings I5 and I6. These conduits assume a position in alignment with each other when the two castings are secured together by means of the studs I8 and a liner 28 is installed in the conduits to provide a continuous passage for the fuel mixture through the two castings. In Figure 1 of the drawings. the location of the conduits are predetermined so that the passage 29 extends from the carburetor 23 to the intake openings 38 located in the sides of the cylinder 24. In actual practice, the conduit 26 extends through the fuel tank in heat conducting relation to the fuel in the tank, and this is important in that it tends to maintain the fuel mixture flowing through the passage 29 at a more uniform temperature.

The cylinder isalso provided with an exhaust opening 3I and in accordance with the principle of two cycle operation, both the intake and exhaust openings are controlled by a piston 32 reciprocably mounted in the cylinder 24. In accordance with conventional practice, the top wall of the piston cooperates with the adjacent walls of the cylinder to form a combustion chamber 33 and the compressed fuel mixture in this chamber is ignited by a spark plug 34 housed in the intermediate section I6 of the motor. The spark plug 34 is electrically connected to the coil 221 and the latter in turn is connected to the distributor 35 by means of electrical conductors 36 extending through a conduit 31 which is cast integral with the upper section I5 of the mold. It will be observed that the conduit 31 also extends through the fuel tank and in this manner exterior plumbing or accessories is reduced to the minimum.

The piston 32 is operatively connected to the eccentric crank pin 38 on the shaft 35 by means of a connecting rod 39 in such a manner that reciprocation of the piston effects a rotation of the crankshaft 25. This crankshaft is supported at points spaced axially thereof in anti-friction bearings 40 and the rear end of the shaft extends axially through the packing gland 4I for attachment to the propeller 42. The propeller is protected by means of a guard 43 cast integral with the bottom section I1 in advance of the propeller and is preferably formed hollow toreduce the weight to the minimum. It may be pointed out at this time that the propeller is prevented from sucking air by means of the cavitation fitting 44 secured to the intermediate casting I6 directly above the propeller blades. The cavitation fitting 44 is arcuate, as shown in Figure 3, so as to assist in turning the motor about the steering axis 45. This plate also operates to reduce the splash when the motor is lowered in water, subsequent to the cranking operation.

As stated above, provision is made herein for turning the engine about the up and down axis V45 in order to control the path of movement of the boat upon which the engine is mounted. In detail, a pair of vertically spaced lugs 41 and 48 are cast integral with the rear wall of the section I5 of the engine. with aligned openings therethrough for receiving the vertical spindle 49 which is secured to the bottom lug 48 by means of the set screw 5I]l and forms a bearing for the sleeve 5I. The sleeve 5I extends between the two lugs and is secured to the mounting bracket assembly 52 in a manner to be more fully hereinafter described. The motor is actually turned about the axis of the sleeve 5I by means of a handle 53 having a grip 54 conveniently located for manipulation by the operator a'nd having a laterally projecting portion 55 extending through a bore 56 formed in a boss cast integral with the section I5 of the engine. The axis of the bore 56 is located in a plane perpendicular to the plane of the turning axis 45 and is offset a sufficient distance in rear of the latter axis to provide for readily turning the engine about the axis 45. Although, sufficient friction inherently exists in the pivotal mounting for the handle to normally maintain the latter in its operative position, nevertheless, the handle may be readily swung downwardly when the motor is being transported, or packed for shipping.

Referring now to the assembly 52 for mounting the engine upon a boat, it will be noted that this assembly comprises a bracket 60 pivotally connected to the sleeve 5I by means of a pin 6I secured to a boss 62 formed on the rear side of the sleeve 5I. The axis of the boss 62 is located in a plane perpendicular to the steering axis 45 in order to permit the engine to be swung to either of the two positions shown in Figure 2. Upon reference to Figure 5, it will be noted that the opposite ends of the pin 6I project beyond the corresponding ends of the boss 62 and extend through bosses 64 formed in the rear end of the bracketSIl. A rubber bushing 65 insulates the pin 6I from metallic contact with the bracket so that vibrations set up in the engine are absorbed prior to being telegraphed to the bracket 60.

The bracket 60 is provided with a downwardly` opening clamp 66 adapted to fit over the sup-y Both of the lugs Iare provided tively insulating the engine from the boat. If f desired, the wall 61 may be ribbed, as at 10, to increase the strength thereof while maintaining the weight -of the bracket to the minimum. A suitable clamping screw 1I is threaded in the front wall of the portion 66 and this screw is provided with an enlarged head 12 which cooperates with the rear wall 61 in effectively clamping the motor to the boat.

With the above construction, it will be noted that the engine may be swung fromthe dotted line position thereof shown in Figure Tfbout the axis of the pin 6I to the full line position illustrated'in the same figure wherein the propeller 42 is located above the water level. The engine is held in its raised position by means of a latch member 15 slidably mounted in the bracket 60' swinging the motor to the above named position, the operator merely pushes the latch member 15 rearwardly to engage the end 16 in the opening 11. Movement of the latch member into locking engagement with the lug 41 of the motor is cilected against the action of the spring 18 which is located in a bore formed in the bracket 60 and irictionally engages the latch member.

When the latch member is in locking engagement with the lug 41, the engine is rigidly held from swinging movement about the axis of the pin 6I and, in view of the fact that the opening 11 through the lug 41 is offset with respect to the axis of swivel movement of the engine, it follows that the latch also-prevents oscillaltion of the engine about the swivel axis 45. In other words, the engine is rigidly held against movement when in its tilted position shown by the full lines in Figure 2 and the engine may be readily started by merely cranking the propeller 42. Rotation of the propeller to effect the cranking operation is accomplished by reeving a flexiblc member around a pulley 18 secured to the rear face of the propeller 42 in concentric relation with the crankshaft 25, with the result that when the exible member is unwound, the shaft is rotated sufficiently to accomplish the cranking operation. As'stated above, the propeller 42 is spaced above the water level during the cranking operation so that it is not necessary to overcome the resistance offered to rotation of the propeller by the water and, as a result, starting of the engine is appreciably facilitated.

The carburetor 23 supplies fuel mixture to the combustion chamber 33 through the passage 29 and this carburetor is shown in Figure 8 as being secured to the top wall 2| of the fuel tank or section I5 of the engine. Upon reference to Figure 1, it will be noted that both the carburetor and ignition coil 23 are enclosed by means of a cover secured to the section I5 by the screws 8|. The side Walls of the cover 80 are slotted adjacent the carburetor to provide ports 83 through which air flows into the Venturi .passage 84 of the carburetor. As shown in Figure 8, fuel is supplied to the Venturi passage for mixture with the air through a. jet 85 controlled by a needle valve 86 threadedly mounted to vary the area of the jet from zero to a predetermined maximum. The fuel is supplied to the jet through the medium of a conduit 81 having one end extending into the fuel tank 20 to a point adjacent the bottom of the latter and having the opposite end communicating with the valve controlled jet.

With the above construction, it will be noted that when the piston of the engine is on its suction stroke, fuel is drawn upwardly through the conduit 81 and is injected into the air stream passing through the venturi 84 so as to cornmingle with the air prior to being admitted through the intake ports 30 in the cylinder wall 2l of the engine. The speed of the engine or the volume of fuel mixture supplied is controlled by 'a throttle Valve 88 mounted for sliding movement transversely of the venturi opposite the fuel jet 85. It will be observed from Figure 8 that the inner end o-f the throttle valve extends into the venturi to vary the effective cross sec tional area thereof and that the valve is held in any one of its several adjusted positions by means of a spring pressed detent 89. This particular type of throttle valve is preferred since it maintains the proper air and fuel ratio, irrespective of the speed of the engine or the volume of fuel mixture supplied to the combustion chamber.

It will. also be observed from Figure 8 that' provision is made herein for choking the engine by dimensioning or closing entirely the air passage through the venturi 84. This is accomplished, in the present instance, by providing a vertically reciprocable valve disc 90 on the cover 80 directly above the end oi the venturi 84 and normally maintained in its inoperative position with respect to the venturi by means of a spring 'I'he spring 9| surrounds a plunger 92 recip-i rocably mounted in the cover 80 and having the valve dise 90 secured to the lower end thereof. A suitable abutment 93 is secured to the upper end of the plunger for engagement with the corresponding end of the spring and the opposite end oi the spring seats upon the cover. When it 1s desired to choke the engine, the valve plunger 92 is merely depressed to seat the disc 90 over the air intake opening of the Venturi passage 84.

In order that fuel may be drawn upwardly through the passage 81 to the carburetor jet, provision is made herein for venting the interior of the fuel tank to the atmosphere. In Figure 11, I have shown a filler opening 95 for the fuel tank adapted to be closed by means of a cap 96 having a vent 91 therethrough. In the present instance, the vent is adapted to be closed by means of a valve member 98 threaded in the cap and having an enlarged head 99 positioned for convenient manipulation by the operator. With this construction, it will be noted that by closing the vent 91 with the valve 98 and by closing the jet 85 with the needle valve 86, the motor may be transported without draining the fuel tank.

Referring now more in detail to the construction of the distributor 35 for controlling the ignition of the fuel mixture in the combustion chamber 33, it will be noted that this distributor comprises relatively movable contacts |00 and |0I. fIhe contact |00 is electrically connected to the ignition coil 22 and is supported in the intermediate casting I6 of the engine by means of the flexible member or spring |02. The cooperating contact I 0I is fixed to the intermediate casting I8 in a position to be engaged by the contact |00 under the inuence of the spring I 02. 'Ihe contact |00 is positively moved away from the contact |0| in timed relation to the crank travel to effect ignition of the fuel mixture in the chamber 33 by means of a cam |03 secured to the crankshaft and engaged by the lower end of a vertically movable plunger |04 having the upper end abutting the spring |02. The plunger is normally urged into frictional engagement with the cam by means of the spring I 05 surrounding the plunger and located in aligned bores formed in the two castings I5 and |1. 'I'he arrangement is such that when the high point of the cam cornes in contact with the lower end of the plunger |04, the latter is raised against the action of the spring |05 to move the contact |00 in a direction away from the contact IOI. On the other hand, when the lower end of the plunger passes over the high point of the cam, the spring |02 returns the contact |00 into engagement with the cooperating contact |0|. This relatively simple mechanism controls the ignition of the fuel mixture in the combustion chamber 33 and operates efficiently without attention over a long period of time.

Upon completion of the power stroke of the engine, the burned gases are exhausted through quiet operation.

' ly noiseless.

the opening leased below the 3| in the cylinder wall and are rewater level in order to provide As shown in Figure l, the exhaust opening 3l communicates with a vertically upwardly extending pipe H0 having the upper end communicating with a muiiler lill secured to the casting I5 by means of the set screw 50. The muffler, in turn, communicates with a downwardly extending pipe H2 having the lower end extending below the water level. With this construction, extremely quiet exhaust is provided and operation of the motor is rendered practical- To avoid any possibility of water being drawn upwardly through the muffler in the event that the engine stalls, a small vent Ill is formed in the exhaust passage in a position to establish communication with the atmosphere. This vent is of sumcient size to destroy any partial vacuum or suction that may be set up in the exhaust passage in the event the engine stalls.

Thus, from the foregoing, it will be observed that I have provided a relatively simple portable marine engine capable of being inexpensively manufactured and assembled. It will also be noted that the engine incorporates numerous features which not only contribute to the simplicity of design, but also appreciably enhance the performance of the same.

What I claim as my invention is:

1. In a portable marine engine, the combination with an engine unit including a submersible propeller and means for turning the engine about an up and down axis for steering purposes, of means for attaching the engine unit to a support including a bracket hingedly connected to the engine unit to permit swinging the unit from a position wherein the propeller is submerged to a position wherein the propeller is located above the water level, means accessible in the last named position of the engine unit for cranking said engine and unitary latch means; mounted on the bracket and engageable with the engine unit in the tilted position to rigidly hold the engine unit against both turning and swinging movement during cranking of said engine.

2. In a portable marine engine, the combination with an engine unit including a submersible propeller and means for turning the engine about an up and down axis for steering purposes, of means for attaching the engine unit to a support including a bracket, a hinge pin extending transversely of the axis of turning movement of the engine unit and pivotally connecting the bracket to said engine unit permitting the latter to be tilted from a position wherein the propeller is submerged to a position wherein the propeller is spaced above the water level, means accessible in the last named position of the engine to crank the latter and a latch carried by the bracket and engageable in an opening in the engine unit predeterminedly located with respect to the axes aforesaid to rigidly hold the engine unit in its tilted position against turning movement about the up and down axis aforesaid during cranking of the engine.

3. In a portable marine engine, the combination with an engine unit including a submersible propeller and means for turning the engine about anup and down axis for steering purposes, of means for attaching the engine unit to a support including a bracket, a hinge pin extending transversely of the axis of turning movement of the engine unit and pivotally connecting the bracket to said engine unit permitting the latter to be tilted from a position wherein the propeller is submerged to a position wherein the propeller is spaced above the water level, means accessible 4 in the last named position of the engine lunit to crank the latter, a latch carried by the bracket and engageable in an opening in the engine unit predeterminedly located with respect to the axes aforesaid to lrigidly hold the engine unit in its tilted position against movement about either the tilting or turning axis of the engine unit during the cranking operation, and resilient means insulating the engine unit from metallic contact with the bracket.

4. In a portable marine engine, the combination with an engine unit having a fuel tank and a submersible propeller positioned below the fuel tank, of a bracket for removably attaching the engine unit to a support, means supported by the fuel tank of the engine unit and connected to the bracket permitting turning movement of the engine unit about an up and down axis relative to the bracket,'a hinge pin also carried by the fuel tank and extending transversely of the turning axis to permit tilting of the engine from a position wherein the propeller is submerged to a position wherein the propeller is located above the water level, and means carried by the bracket and engageable with the fuel tank for rigidly holding the engine unit in its tilted position against movement about either the tilting or turning axes of the engine unit.

5. In a portable marine engine, the combination with an engine unit having a fuel tank and having a submersible propeller, of a bracket for removably clamping the engine unit to a support, a pin supported by the fuel tank with its axis extending substantially vertical, a sleeve rotatably mounted on the pin to provide for turning movement of the engine unit about the axis of the pin, a hinge pin extending transversely of the axis of the turning pin and pivotally connecting the sleeve to the bracket to permit tilting of the engine from a position wherein the propeller is submerged to a position wherein the propeller is located above the Water level, and a latch member carried by the bracket and movable into engagement with the engine unit when the latter is in its tilted position to rigidly hold the engine unit in said position against movement about the axes of said pins.

6. In a portable marine engine, the combination with an engine unit having a submersible propeller and having an exhaust conduit with the outlet end adapted to extend below the water level, of means for turning the' engine about an up and down axis for steering purposes, means for attaching the engine unit to a support including a bracket hingedly connected to the engine unit in a manner to permit swinging of the engine unit to a position wherein the propeller and outlet end of the exhaust are submerged to a position wherein the propeller and outlet end of the exhaust are located above the water level, means accessible in the last named position of the engine unit for cranking said engine, and unitary latch means mounted on the bracket and engageable with a part of the engine unit in the tilted position thereof to hold the engine unit against turning and swinging movement during cranking of the engine.

7. In a portable marine engine, the combination with an engine unit including a submersible propeller and means for turning the engine about an up and down axis for steering purposes, of means for attaching the engine unit to a supi. pore windings hinge pin extending ineens for attaching the engine unit to a sup- 'j tran'gYE'selyJJotftheixis 'of turning movement ot port lincluding a bracket unit hingedly connected ,i .jthc engine pivotally connecting the latter tothe engine to permit swinging the latter from a ,to the 'bracket to permit the engine unit to be position wherein the propeller is submerged to y V`f 'ly1hold the engine unit in a tilted position against the Water level, and a single latch element vboth turning and swinging movement relative to mounted on one of the units and engageable with the bracket. the other unit in the tilted position of the engine 8. In a portable marine engine, the comhinnto rigidly hold the latter against both turning 10 tion with an engine unit including a aubmersible and swinging movement.

propeller and means for turning the engine about anupanddownaxisforxteerlngpurpocesmt DOUGLABRCLARKE.

I; 15 tilted. 'and unitary latch means eii'ective to rigida position wherein the propeller is located above

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