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Publication numberUS2201987 A
Publication typeGrant
Publication dateMay 28, 1940
Filing dateMar 11, 1936
Priority dateMar 11, 1936
Publication numberUS 2201987 A, US 2201987A, US-A-2201987, US2201987 A, US2201987A
InventorsWarren C Conover
Original AssigneeOutboard Marine & Mfg Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Outboard motor
US 2201987 A
Abstract  available in
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

y 28, 1940- w. c. CONOVER 2,201,987

OUTBOARD MOTOR Filed March 11, 1936 4Shets-Sheet 2 J2Uer27b77- war/"e126? Canal/6r; aw WM W 4 y 28, 1940- w. c. CONOVER 2,201,987

OUTBOARD MOTOR Filed March 11. 1936 4 Sheets-Sheet 4 Patented May 28, 1940 UNITED STATE oU'rBoAan Moron Warren G. Conover, Waukegan, Ill., allignor. by

mesne assignments, to Outboard,

Marinedv Manufacturing Company, Wilmington, DeL, a corporation of Delaware Application March 11, 1936, Serial No. 68,238

3 Claims.

This invention relates to improvements in outboard motor.

It is the object of the invention to provide a practical form of outboard motor in whichthe power head has been so lowered that its center of gravity is approximately at or below the level of the transom. I propose in this manner to improve the stability of the craft to which the motor is attached; to accomplish a very substantial reduction in noise, and to remove all dirty or greasy parts, and all electrical connections, to a position where they will not accidentally be contacted by the operator.

In order to make my improved invention practicable for modern outboard motor conditions and modern boats, it is a further object of the present invention to provide an extended mm between the sub-crank case swivel bearing and g the bracket pintle upon which the motor tilts for steering, thus permitting the said swivel bearing to be located well below the top of the boat without interfering with the tilting function.

It is a further and very important object of the invention to enclose, at least to a substantial degree, the entire power head in a sheath or casing which protects all .of the parts from contact with the water. The boats with which outboard motors are used now commonly have low transoms, and in order that the power head may be lowered with respect to the transom, it is necessary that it be brought into close proximity to the normal water line where waves might readily splash it but for the protection thus provided. The mere location of the power head behind the transom is an important factor contributing to the reduction of noise and the elimination of dirt, and the enclosing casing makes an important additional contribution to these objectives and also gives a smooth and more or less streamlined enclosure which enhances the appearance of the device.

In the drawings:

Figure 1 is a view partly in elevation and partly in section, of an outboard motor embodying the principles of this invention.

Figure 1a is a fragmentary detail view showing a modified construction in which the subcrank case swivel bearing is reduced in length and is supplemented by a second swivel bearing above the crank case.

Figure 2 is a front and part sectional view of the motor shown in Figure 1.

Figure 3 is a top view of the motor shown in Figure 1, the bracket being omitted.

Figure 4 is a view mostly in section of a modification. 7

Figure 5 is a sectional view at the' top of the casing, of the motor shown in Figure '4.

Figure 6 is a front view of the motor unit shown in Figure 4, the bracket being omitted.

Figure '7 is a section taken on the line 1-1 of Figure 4.

Figure 8 is a section taken on the line H of Figure 4.

Figure 9 is a plan view on an enlarged scale,

' of the motor shown in Figure 5.

Figure 10 is a fragmentary detail in section showing the tiller connections to the dirigible drive shaft housing on the inside of the motor casing.

Figure 11 is a detail view in section showing a modified construction employing a single water passage and anti-friction elements in the swivel bearing.

Figure 12 is a detail view in plan of a portion of the transom bracket and the supporting part of the casing of the device shown in Figure 4.

Figure 13 is a detail view in section taken on the line Iii-l3 of Figure 4.

Like parts are identified by the same reference characters throughout the several views.

Referring now more particularly to the drawings, this invention may be illustrated as applied to an outboard motor having a lower driving unit II) as shown in Figs. 1 and 2, with a short drive shaft casing H connecting it to an engine power head l2. At the top of the power head and connected to the engine crank shaft is a fly-wheel l3 of a magneto controlled by a handle it and having a rope starter plate ii at the upper end thereof. At the rear and partially nesting the fiy-wheel I3 is a fuel tank It, and an enclosing casing l'l extends entirely over the power head, over the fuel tank It, and around and over the magneto fly-wheel 13, leaving only the rope starter plate exposed through an opening in the upper side ofthe casing. The casing is secured to the power head in any suitable manner and a portion thereof is engaged between flanges l8 and I9. Exhaust pipe 20 connects the engine cylinder 2| with the rear of the lower unit II which conducts the exhaust gases to an opening 2i below an anti-cavitation plate 22 at the rear of the propeller 23.

This structure as a unit is mounted in a split sleeve swivel bearing 25 at the lower end of an arm 26 which has an offset intermediate portion 21 and an upper end 20 mounted in a transverse pivot 28 in a bracket clamp 88 attachable to a boat transom II by a fastening screw 82.

The bracket clamp has two side portions with the arm 28 mounted upon the pivot 28 between them. Inclined slots 83 in the side portions receive an adjustable thrust bolt 84 engaged by the front edge of the arm 28. Thus the engine and the power head are low with respect to the tilting pivot 28, thereby providing a low center of gravity, making the boat more safe and stable, and less likely to overturn,. and reducing the overall length of the motor from top to bottom.

For steering, the motor is rotatable in the split sleeve 25, and a handle 85 may be secured directly to the casing I1 at one side 01 the flywheel as shown more clearly in Fig. 3.

The device shown in Fig. 1a of the drawings is identical with that shown in Figs. 1 and 2 excepting that the arm 28 of the bracket is provided with an extension 280 ca ying a supplemental swivel bearing in the form of a split sleeve 250 applied to a boss above the crank case. Because of the provision of this supplemental swivel hearing it is unnecessary to employ so long a bearing at I below the crank case, and this effects a further reduction in the center of grav ity of the device.

In the form shown by the remaining figures of the drawings, an engine is enclosed in a casing 5i which has forward extensions 52 for pivotally mounting the entire structure to tilt about a horizontal pintle 53 carried by a bracket 54 secured by a screw clamp 55 to the transom 88 of a boat. Formed unitarily with the casing is a hollow casing extension 51 and a,muiller extension 58. In order that the casing structure may be locked against tilting during the reversal, I may either provide automatically interlocking parts as disclosed in Patent No. 1,467,641, or I may provide for manual docking of the parts by threading a nut 530 upon the pintle 53 and providing said nut with a handle 53I as shown in Figs. 9 and 11, whereby the clamping pressure of the nut will slightly distort the sides of the bracket against the casing to frictionally resist tilting movement.

Turnable in the casing Si is a lower unit which has a sleeve GI fitting within the swivel bearing 51 and adapted to receive the extended engine drive shaft leading to the propeller 68. A gear 84 secured at the top of the casing 8| provides means for retaining the washers and 88 in place to form a bearing.

Water passages 81 and 68 terminate at an arch 88 over the path of the propeller blades and these passages extend upwardly to ports 10 and 1| respectively. The port 10 communicates with a passage 13 extending upwardly in the swivel bearing 51 and thence around the outside of the casing in a passage 14 as shown more clearly in Figures 4 and 8. At the top of the muffler extension 58 is a partition 15 below a casing wall 18 with a wall 11 dividing this flat chamberinto two passageways 18 and 19, the former communicating with the water passage 12 and the latter communicating with the passage 14.

The engine 50 has a cylinder casing and a cylinder cap 8| therefor provided with a water' jacket and a pipe connection 82 extends through the casing wall 16 and into communication with the passageway 18 at the bottom of the water jacket, and a pipe connection extends from the top of the water jacket through the cylinder head 8| and downwardly to the passageway 19 at the other side of the partition 11. Thus when the engine is in operation a supply of cooled water is impelled by the propeller l8 upwardly through the passage 81, port 18, passage 12, possageway 18, pipe fitting 82 through the'engine cooling system, outwardly through the pipe conneetion 88, passageway 18, passages 14, 18, port 1i, and passage 88 from the lower casing 88 in front of the propeller 88.

As the lower driving unit is rotatable in the relatively fixed casing II for the purpose of steering, the passages 12 and 13 as shown more clearly in Fig. 7, extend partially around the casing extension 51 less than one hundred eighty degrees so that the ports 10 and 1i will remain in communication with them respectively during the ordinary steering movements oi the lower driving unit 60. However, in case it is desired to reverse the position of the lower driving unit, for propelling the boat rearwardly, the ports 18 and 1i will be reversed with respect to their ordinary passages 12 and 13 respectively and the direction of flow of the cooling water will therefore be reversed in the passages and water jacket above the ports 10 and 1|. -However, as the possages and water jacket above these ports 10 and ll are all full of water at the time reversal takes place the pressure and suction exerted by the propeller is suiilcient to reverse the flow of cooling water through the water jacket and the connected passages in the casing 5|.

At the rear oi. the casing Si is an opening closed by a door 85 mounted on a hinge 88 at one side thereof and substantially conforming to the outline of the casing to provide a smooth and substantially stream line surface, the door being normally held in closed position by a spring 81 connected at one end to a rib 88 of the door and at the other end to a suitable fixed portion of the engine. The spark plugs 88 and a valve 90 in the gasoline line connection 83 are freely accessible through this opening when the door 85 is maintained in open position, and the closure of the door protects these parts and closes the casing against the admission of water.

At one side of the engine cylinders is a muiiler casing 92 which has an opening registering with the exhaust openings of the cylinder and has a passage 93 extending downwardly at the side of th casing 5i and registering with an opening 94 in the wall of the mufller 58 below its partition 15 so that the exhaust is discharged into the muilier extension 58 and escapes through a discharge passage 58' at the bottom thereof below an anticavitation' plate extending from the outer surfaces of the lower driving unit 60 and the lower rear end of the muiiler extension 55.

In order to rotate the lower unit in the casing 51, for steering, an idler gear 88 is mounted in the casing which meshes with the gear 84 and with a gear 91 at the opposite side thereof at one side of and beyond a flywheel magneto 98 and a starting plate I00 at the top of the motor. A steering handle I02 is secured to the upper end of the shaft 98 and at the outer end is pivoted a. hand lever I03 which has an extension I04 cooperating with a stop I05 on the handle III! so that it will engage the stop both in the horizontal and vertical positions of the handle. This steering handle is therefore freely rotatable in either direction and the lower driving unit is correspondingly rotated as the gear 91 is preferably of the same diameter as the gear 64 with which the idler 96 meshes.

In the structure thus described the casing may house merely the engine as shown, with an extension H16 about the flywheel magneto and with a separate and outer fuel tank I01 as shown, or these parts may be included in the same casing as shown in Figs. 1, 2 and 3. The outline of the lower unit also closely conforms to the adjacent surface of the mufiier extension 58 so that when in normal position they are substantially parallel and adjacent each other.

To provide a freely rotatable connection between the supporting casing and the lower unit which is rotatable for steering, roller bearings I I may be inserted between crank case extension portions H I and H2 corresponding to the casing members 51 and 60 respectively. In this form a single water passage H3 is shown having an outer annular groove H1 between the bearings Hll which continuously registers with a passage H5 in the casing Ill. After passing through the water jacket of the engine the cooling water is discharged directly into the muffler extension as shown in Fig. 4 or it is discharged overboard from the engine. Between the casings is'a cork seal H6 engaging an inclined surface H'I above the annular groove H4 and pressed in engagement therewith by a spring H8 which prevents any of the water or air from passing upwardly between the casings. A projection H9 at the bottom of the annular groove H4 forms a substantially tight connection with the outer casing I l I so that any small water casings will serve to lubricate the lower bearings H0.

Many of the details of outboard motor structure are omitted from the drawings and description because they have no special reference to the present invention and would only obscure and confuse the invention in this case.

With both of these constructions the outboard motors are mounted to tilt about a vertical axis substantially at the top of the engine, the portions which are pivoted for steering and the pivotal mounting thereof being well below the engine itself and substantially in the shaft casing portion between the power head and the lower driving unit. The arm which extends from the tilting axis to the swivel bearing may be separate 'as suggested in Fig. l and Fig. 1a, or it may include or be a part of the engine or engine case as suggested in Fig. 4 and Fig. 11. This provides a wider bearing portion and also reduces the length of the shaft casing between these parts to make them shorter than the constructions heretofore employed. The resulting structure is less in height and the engine being mounted lower with respect to the upper edge of the boat transom provides a safer outboard motor structure for use leakage between the in connection with small boats. By providing a substantial closure for the engine and operating parts it is possible to'mount the motor lower at the back of a boat and stillto experience no detrimental effects from the splash of the water short-circuiting the spark plugs or other electrical connections.

I claim:

1. In an outboard motor structure, the combination with a relatively stationary power head and a lower unit rotatable for the reversal of its direction of propulsion, of a bearing including relatively stationary water cooling ducts extending from said bearing to and from said power head, and complementary ducts connected with said lower unit and extending from and to submersible inlet and outlet ports therein, and means for circulating water through said ducts, the ducts of the lower unit being adapted to register with different stationary ducts in said bearing according to the direction of propulsion of said lower unit.

2. In an outboard motor structure, the combination of a relatively stationary power head, a bearing therebeneath provided with oppositely ported walls and stationary ducts leading from the ports in said walls to and from said power head, means rotatable in said bearing and provided with a submersible lower unit having inlet and outlet ports, ducts leading from the inlet and outlet port to a position in said means registerable with said first mentioned ducts, and a propeller carried by said lower unit and positioned in association with at least one of said ports to circulate water through said ducts, the ducts leading from the lower unit being arranged to register with different ports in said bearing according to the position of said lower unit in its rotative adjustment respecting said bearing.

3. In an outboard motor structure, the combination with a casing and a power head enclosed therein, of a swivel bearing below said casing, a dirigible shaft housing and lower unit journaled in said bearing and extending into said casing, a vertical tiller shaft rotatable in said casing and provided therewithin with driving connections to said shaft housing, a crank on said tiller shaft exposed above said casing, and a handle on said crank pivoted for movement from the plane of said crank to an upright position thereon, said tiller shaft carrying said crank at a level such that it may be rotated for the reverse of the direction of propulsion of the lower unit without interference with said casing.


Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3240181 *Jun 5, 1964Mar 15, 1966Surflo IncOutboard motor attachment
US5603644 *Oct 11, 1991Feb 18, 1997Yamaha Hatsudoki Kabushiki KaishaJet propulsion boat
US5707264 *Jun 7, 1995Jan 13, 1998Yamaha Hatsudoki Kabushiki KaishaJet propulsion boat
U.S. Classification416/93.00R, 440/88.00C, 440/88.00F, 185/41.00R, 440/88.00M, 384/317, 384/294, 440/88.00R, 440/89.00J
International ClassificationF02B61/04, B63H20/12, F01P3/20, F02B75/20, B63H20/34, B63H20/10, F02B75/18
Cooperative ClassificationF02B61/045, B63H20/34, F02B2075/1808, B63H20/12, B63H20/10, F02B75/20, F01P3/202
European ClassificationB63H20/12, F02B75/20, B63H20/10, B63H20/34, F01P3/20B