EP0037690A1

EP0037690A1 - Marine outdrive apparatus

Info

Publication number: EP0037690A1
Application number: EP19810301340
Authority: EP
Inventors: Howard Martin Arneson
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-04-07
Filing date: 1981-03-27
Publication date: 1981-10-14
Also published as: DE3164280D1; AU542771B2; CA1149684A; JPS56163994A; JPH0618194U; EP0037690B1; AU6866181A

Abstract

A marine outdrive attachable to the transom of a boat having an inboard engine. The marine outdrive includes a support casing (23) securable to the boat's transom (20) and having a ball socket (24). The ball socket receives the ball (32) of a propeller shaft carrier (30). A drive shaft (38) connectable to the inboard engine is journalled in the support casing. A propeller shaft (40) is journalled in the propeller shaft carrier. A double universal joint (46) connects the two shafts, with the center of such joint coinciding with the point about which the ball pivots within the socket. Hydraulic steering cylinders (108,110) are attached to the propeller shaft carrier to swing about a generally vertical steering axis extending through the aforementioned pivot point.

A hydraulic trim cylinder (140) extends between the transom and the propeller shaft housing to swing the housing vertically about a horizontal trim axis extending through the aforementioned pivot point.

Description

The present invention relates generally to marine drives and more particularly to a marine inboard-outboard drive for a marine engine positioned within the boat upon which the drive is mounted. So-called inboard-outboard drives have been in use for many years. Examples are shown in U.S. Patent No.1,798,596; U.S.Patent No.2,977,923; U.S.Patent No.3,088,296 and U.S.Patent No.3,382,839. These inboard-outboard drives are utilized in propelling boats generally having large inboard engines. Such drives employ a drive shaft extending through the transom of a boat, connected to a generally vertically extending shaft which in turn is connected to the propeller shaft. Such drives have many of the advantages of outboard motors. By way of example the propeller supporting member of the drive can be rotatably lifted when the boat is in shallow water or for inspection and maintenance of the propeller and its shaft. It is another important advantage of such inboard-outboard drives that the trim of the boat may be adjusted by rotating the propeller supporting member about a horizontal axis. In addition to the tilting feature inboard-outboard drives are rotatable about a generally vertical axis to steer the boat. A common arrangement provides a universal joint about which the propeller supporting member of the drive can be both tilted and steered, as for example the arrangement shown in the aforementioned U.S. Patent No. 3,088,296.
Although the conventional inboard-outboard drives offer the aforementioned advantage and have been commercially successful, they also embody inherant disadvantages. By way of example, such drives are relatively heavy, expensive to manufacture and maintain, and are inefficient in transferring power from the engine to the propeller. A power loss of as much as 17% can occur because of the transfer loss through the gears and couplings as compared to a direct drive. Moreover, since the propeller carring member of such drives generally extend a considerable distance below the water's surface, such drives offer appreciable drag. Attempts have been made to overcome the disadvantages of conventional inboard-outboard drives by eliminating the generally vertical shaft and coupling the drive shaft directly to the propeller shaft. Examples are disclosed in U.S. Patent No.1,864,857 amd U.S. Patent No.3,933,116. These prior arrangements, however, involve complicated and impractical mechanisms which have not met with commercial success.
Thus, the drive arrangement of U.S. Patent No.3,933,116 utilizes a surface piercing propeller keyed to a propeller shaft that is moved about a horizontal axis for steering and about a vertical axis to trim the boat. The design of this drive requires the drive shaft to be disposed at an appreciable distance above the bottom of the boat's transom. This requires the propeller shaft to assume a vertically tilted position thereby pushing the bow of the boat downwardly at higher speeds.
The present invention provides marine outdrive apparatus attachable to the transom of a boat having an inboard engine, said apparatus comprising being characterized by the combination of

a support casing securable to the transom of said boat;
a ball socket positioned within said support casing;
a propeller shaft carrier having its front end formed with a ball that is universally pivotally carried by said ball socket;
a drive shaft journalled in said support casing and connectable to said inboard engine;
a propeller shaft rotatably supported by said propeller shaft carrier, the aft end of said propeller shaft receiving a propeller, and said shafts extending generally longitudinally;
universal joint means connecting the aft end of said propeller shaft, the center of said universal joint means coinciding with the pivot point about which said ball pivots relative to said ball socket; and,
said propeller shaft carrier swinging laterally about a generally vertical steering axis that extends through said pivot and vertically about a horizontal trim axis that extends through said pivot point.

Marine outdrive apparatus embodying the present invention utilizes a support casing secured to the boat's transom and provided with a ball socket, a propeller shaft carrier formed at its front end with a ball that is universally pivotally carried by the ball socket, a drive shaft journalled in the support casing and connected to the boat's inboard engine, a propeller shaft journalled in the propeller shaft carrier, with the aft end of such shaft being keyed to a propeller and with the shafts extending generally longitudinally. Universal joint means connect the shafts, with the center of the universal joint means coinciding with the pivot point about which the ball pivots relative to the ball socket. This arrangement permits the propeller shaft housing to swing laterally about a generally vertically extending steering axis that extends through the afore-mentioned pivot point, and additionally permits the propeller shaft carrier to be trimmed vertically about a horizontally extending trim axis that extends through the same pivot point. The support casing and propeller shaft carrier extend rearwardly from the boat's transom horizontally or at a very slight angle to the horizontal, and the shaft is keyed to a surface-piercing propeller. The marine outdrive apparatus of the present invention.utilizes a minimum number of rugged parts and offers minimum water resistance. as compared to heretofore proposed marine drives.
Marine outdrive apparatus embodying the present invention also lends itself to the utilization of hydraulic steering cylinders and a hydraulic trim cylinder for providing precise steering and for effecting trimming of the boat while such boat is underway. These steering and trim cylinders are operatively connected to the propeller shaft carrier in such a manner as to reduce the twisting effect of the propeller torque.
These and other features of the invention will become apparent from a consideration of the following detailed description with reference to the drawings, in which:-

FIG.l. is a rear perspective view of a preferred form of marine outdrive apparatus embodying the present invention.
FIG.2 is a side elevational view of said apparatus;
FIG.3 is a broken vertical sectional view taken in enlarged scale along line 3-3 of FIG. 1 ;
FIG.4 is a vertical sectional view taken in enlarged scale along line 4-4 of FIG.2;
FIG.5 is a fragmentary top plan view in reduced scale showing the steering arrangement utilized with said apparatus.
FIG.6 is a broken vertical sectional view taken along line 6-6 of FIG.2;
FIG 7 is a broken vertical sectional view taken along line 7-7 of FIG.2;
FIG.8 is a veritcal sectional view taken in enlarged scale along line 8-8 of FIG.1;
FIG.9 is a schematic view of said marine outdrive apparatus, particularly showing the relationship between the steering axis and trim axis thereof;
FIG.10 is a diagrametric view showing a steering and trim control system for said apparatus;
FIG.11 is a top plan view of an embodiment of marine outdrive apparatus embodying the present invention employed with a pair of inboard engines; and
FIG.12 is a broken vertical sectional view taken along line 12-12 of Fig. 11

Referring to the drawings and particularly FIGS 1-10 therefore, there is shown a preferred form of marine outdrive apparatus A embodying the present invention adapted for use with a conventional boat B having a transom 20 upon which said apparatus is mounted. The apparatus includes a support casing, generally designated 22, secured to the boat transom 20 and formed with a ball socket 24. A rearwardly extending propeller shaft carrier, generally designated 30, is formed at its front end with a ball 32 that is universally pivotally carried by the ball socket. A drive shaft 38 is journalled in the support casing, with its front end being connectable to a single inboard engine (not shown) positioned within the hull of boat B. A propeller shaft 40 is journalled by the propeller shaft carrier 30, with the aft end of the propeller shaft receiving a conventional surface-piercing propeller 44. Universal joint means, preferably taking the form of a conventional double universal, or constant speed, joint designated 46, connect the aft end of drive shaft 38 to the forward end of propeller shaft 40. It is important to note that the center of such universal joint 46 coincides with the pivot point 50 about which ball 32 pivots relative to ball socket 24.
More particularly, as shown in FIG 8, support casing 22 has a main body 50 of cylindrical configuration having an open aft end. The front end of such body is integrally formed with a boss 52. The front and rear portions of such boss 52 are provided with needle bearings 54 and 56 respectively that journal drive shaft 38. Oil seals 58 and 60 close the front and rear end of the hub 52, so as to confine a body of oil therewithin. Support casing 22 is rigidly affixed to the rear surface of transom 20 by a plurality of bolts 62. The front end of drive shaft 38 may be connected to a coupling, such as a universal joint 63 forming part of a drive train rotated by an inboard engine Ball socket 24 is preferably formed of a synthetic plastic such as nylon, and includes front and rear pieces 24a and 24b. Front piece 24a abuts shoulder 64 of the support casing, and rear piece 24b is secured by a snap ring. An O-ring 68 is interposed between front and rear pieces 24a and 24b of ball socket 24 in sealing engagement with such pieces and the exterior of ball 32.
Propeller shaft carrier 30 includes a housing 70, the forward position of which is formed with the aforementioned ball 32. The rear portion of housing 70 is provided with an integral externally threaded neck 72, which is engaged with the internally threaded forward end of a frusto- conical tube 74. The truncated rear end of tube 74 is provided with a needle bearing 76 disposed forwardly of conventional oil seals 78. A forward oil seal 80 is disposed between the rear end of housing neck 32 and a forward thrust bearing 82. A rear thrust bearing 84 is positioned adjacent front thrust bearing 82. The space between oil seals 78 and 80 is preferably oil-filled. An 0-ring 86 is interposed between the front end of tube 74 and the rear wall of housing 70.
Referring now to FIGS.l and 2, a lower fin 90 depends from tube 74, with the upper edge of such fin being cast onto such tubes. An upper fin 92 of similar configuration to that of lower fin 80 extends upwardly from the intermediate portion of tube 74. The bottom of upper fin 92 is cast onto the tube. The upper end of upper fin 92 supports a horizontal cavitation plate 94, with such cavitation plate preferably being secured to the front portion of upper fin 92 by means of bolts 98. The rear edge of the cavitation plate 94 overhangs propeller 44 to protect it against contact with a dock or the like. Such cavitation plate also contains the boats roostertail. The intermediate portion of both sides of tube 74 is provided with a pair of ears 100 and 102'. Such ears pivotally receive brackets 103 affixed to the aft free ends of plungers 104 and 106 of port and starboard power-operated hydraulic steering cylinders 108 and 110, respectively. The forward end of such steering cylinders are provided with spheres 112 and 114. Such spheres 112 and 114 are rotatably positioned within complimentary recesses 116 and 118 formed in a pair of mounts 120 and 122. Such mounts are preferably cast onto the mid-portion of opposite sides of support casing 22. The pivot points 124 and 126 about which spheres 112 and 114 rotate relative to their sockets 116 and 118, are disposed upon a horizontal line 128 (FIGS.5 and 9) extending through the aforementioned pivot point 50 about which ball 32 rotates relative to its socket 24, said line being normal to the longitudinal axis of the drive shaft 38. The front and rear portions of steering cylinders 108 and 110 are provided with conduits 130,131,132 and 133 in communication with a conventional hydraulic steering system such as shown in FIG.10
Referring particularly to FIGS 1,2 and 4 a hydraulic trim cylinder 140 and plunger 142 extends between the boat's transom 20 and the propeller shaft carrier 30. The plunger 142 is locked against rotation relative to its cylinder 140 as by complementary splines and grooves indicated at 143 in FIG. 1. The front end of the cylinder 140 is provided with a sphere 144 received within a socket 145 formed in a mounting 146. The front end of such mounting 146 is provided with a pair of ears 148 and 150 rigidly bolted to the transom 20 by fasteners 151. The rear end of plunger 142 is provided with a bifurcated bracket 152 which stradles an upwardly extending pad 154 rigidly affixed to the upper intermediate portion of tube 74. A pivot pin 156 interconnects bracket 152 and pad 154. Hydraulic conduits 158 and 160 connect the front and rear ends of trim cylinder 140 with a conventional hydraulic system wuch as shown in FIG.10.
Referring to FIG 3, socket 145 and hence trim cylinder 140 and its plunger 142 are locked against rotation relative to mount 146 by an upstanding pin 170 disposed within an arcuate slot 172 formed on the underside of sphere 144 along the center line thereof.
Referring now to FIG 10, there is shown a diagrametric view of a steering and trim control system which may be utilized in the operation of the aforedescribed embodiment of the present invention. The system includes a conventional power source 180, such as a conventional electric motor coupled to a hydraulic pump 181. A reservoir 182, conventional control valves 184 and 186 and suitable conduits connect the aforementioned elements with the steering cylinders 108 and 110 and the trim cylinder 140 by reasons of the aforementioned conduits 130,131,132,133,158 and 160. Valve 184 is operatively connected to a steering wheel 190 in a conventional manner while valve 186 is connected to an up-down trim lever 192 in a conventional manner. It will be apparent that rotation of steering wheel 190 will rotate valve 184 so as to control the flow of pressurized hydraulic fluid from pump 181 to steering cylinders 108 and 110. In this manner the plungers 104 and 106 of such steering cylinders will be concurrently extended and retracted so as to swing the propeller shaft carrier 30 laterally about a generally vertical steering axis 5-5 that extends through point 50 about which ball 50 pivots relative to ball socket 24. As shown in FIG.9, pivot point 164 about which sphere 144 of trim cylinder 140 rotates also lies on steering axis 5-5. In a similar manner, movement of the up-down trim lever 192 will effect rotation of valve 186 so as to control the flow of pressurized hydraulic fluid into the opposite ends of trim cylinder 140 so as to effect extension and retraction of plunger 142 relative to such trim cylinder thereby swinging the propeller shaft carrier 30 vertically about a horizontally extending trim axis T-T extending through the aforementioned pivot point 50 and coinciding with aforementioned line 128, as indicated by the phantom lines in FIG.2. It should be noted that the non-rotatable connection between the trim cylinder sphere 144 and housing 146, and between the trim cylinder 140 and its plunger 142 serves to resist any twisting force applied to the propeller shaft carrier 30 upon rotation of propeller 44. Similarly, the positioning of the steering cylinders and plungers on the center-line of the carrier tends to resist such twisting force.
With reference to FIG. 2, it should be particularly noted that the compact configuration of ball 32 and ball socket 24 make it possible to position support casing 22 at the lower portion of boat transom 20. Accordingly, the propeller shaft 40 may be maintained in close longitudinal alignment with drive shaft 38 during normal forward travel of the boat B. The line of propeller thrust is thereby maintained low relative to the boat and below the boat's center of gravity. Maximum efficiency with respect to the transmission of torque is thereby obtained. Also, the drive shaft 38 may be coupled to any conventional power transfer means and, the engine may be mounted at any convenient location in the boat, including an amidships position or a position just forward of the transom through the use of a conventional transmission.
Referring now to FIGS.11 and 12, there is shown a second embodiment of marine outdrive apparatus embodying the present invention employed with a pair of inboard engines (not shown), mounted within the hull of boat B'. Such embodiment includes a pair of marine outdrives A-1 and A-2 substantially identical to the aforedescribed marine outdrive apparatus A. Accordingly, like parts bear primed reference numerals.
The marine outdrive apparatus of FIGS.11 and 12 utilize a different steering cylinder arrangement than that employed with the embodiment of FIGS.1-10.
This arrangement includes right and left hydraulic steering cylinders 200 and 202 having plungers 204 and 206. The forward ends of the cylinders are respectively secured to spheres 208 and 210. Such spheres are rotatably positioned within sockets 212 and 214 formed in the rear portion of a mount 216. Mount 216 is secured to boat transom 20' by fasteners 218. It will be noted that the points 220 and 222 about which spheres 208 and 210 rotate relative to their sockets are disposed when a horizontal line 224 that is normal to the longitudinal axes of the drive shafts of the marine outdrives A-1 and A-2. Line 224 extends through pivot points 50' about which the balls 32' pivot relative to their sockets 24'. Line 224 coincides with the trim axes T'-T' of the propeller shaft carriers 30'.
The rear ends of steering plungers 204 and 206 are affixed to ears 228 and 230 pivotally attached to brackets 232 and 234 by pins 236 and 238.
These brackets are cast on to the inner surfaces of the intermediate portions of the tubes 74'. A tie rod 220 has its opposite ends secured to brackets 232 and 234 by the same pins. The front ends of steering cylinders 200 and 202 are provided with hydraulic conduits in communication with a conventional control system (not shown) that effects concurrent extension and retraction of plungers 204 and 206 to thereby swing the propeller shaft carrier 30' about a pair of generally vertical steering axes S'-S' which extends through trim axis T'-T' and pivot points 50'.
Propeller shaft carriers 30' are each provided with trim cylinders (not shown) identical to those described hereinabove for swinging such carriers vertically about trim axis T'-T'. As indicated in FIG.12, the pivot points 164' about which trim cylinder spheres 144' rotate relative to their sockets 145' are located on the steering axes S'-S'.
It will be apparent that the operation of the twin engine marine outdrive apparatus of FIGS.11 and 12 will be similar to the operation of the apparatus of FIGS. 1 through 10. Both embodiments of the invention provide high efficiency minimum drag and weight, fool-proof performance, and economical manufacture and maintenance. With respect to maintenance, the propeller shaft 40 may be readily replaced and installed by disconnecting the universal joint 46. Boat trim may be readily adjusted for load and wave conditions. Moreover, it is particular advantage that maximum acceleration can be obtained by raising the propeller relative to the water's surface and increasing engine RPM into the engine's power curve by permitting the propeller to slip, and thereafter lowering the propeller toward the water as boat speed increases. This procedure is especially useful under heavy load conditions.
Various modifications may be made with respect to the foregoing detailed description without departing from the spirit of the present invention.
The marine outdrive apparatus described above does not utilize a propeller supporting member which extends an appreciable distance below the water's surface. Instead such apparatus is particularly adapted to utilize a surface-piercing propeller, the propeller being affixed to the aft end of the drive with the main portion of the drive extending rearwardly from the boat's transom horizontally or at a slight angle to the horizontal. The drive accordingly offers a minimum amount of water resistance.
The marine outdrive apparatus in addition to offering minimum drag, is light in weight, fool-proof in operation, easy to maintain and readily available for maintenance, as compared with conventional inboard-outboard marine drives. Such apparatus may be fabricated of corrosion-resistant materials, such as brass or stainless steel.
The apparatus is highly efficient in transmitting power from the boat's inboard engine to the propeller.

Claims

1. Marine outdrive apparatus attachable to the transom of a boat having an inboard engine, said apparatus being characterized by the combination of

a support casing securable to the transom of said boat;

a ball socket positioned within said support casing;

a propeller shaft carrier having its front end formed with a ball that is universally pivotally carried by said ball socket;

a drive shaft journalled in said support casing and connectable to said inboard engine;

a propeller shaft journalled by said propeller shaft carrier, the aft end of said propeller shaft receiving a propeller, and said shafts extending generally longitudinally;

universal joint means connecting the aft end of said drive shaft and the forward end of said propeller shaft, the center of said universal joint means coinciding with the pivot point about which said ball pivots relative to said socket;

steering means extending between said support casing and said propeller shaft carrier to swing said carrier laterally about a generally vertically extending steering axis that extends through said pivot point; and,

trim means extending between said transom and said propeller shaft carrier to swing said housing vertically about a horizontally extending trim axis that extends through said pivot point.

2. Marine outdrive apparatus as claimed in claim 1 further characterised by

power-operated means for swinging said propeller shaft carrier laterally and vertically.

3. Marine outdrive apparatus as claimed in claim 1 characterised in that

a power-operated cylinder and plunger unit is interposed between said transom and said propeller shaft carrier to effect vertical swinging of said carrier., with said cylinder and plunger unit being locked against rotation relative to said transom and said carrier.

4. Marine outdrive apparatus attachable to the transom of a boat having an inboard engine, said annaratus being characterised by the combination of

a support casing securable to the transom of said boat;

a ball socket positioned within said support casing;

a propeller shaft rotatably supported by said propeller shaft carrier, the aft end of said propeller shaft receiving a propeller, and said shafts extending generally longitudinally;

universal joint means connecting the aft end of said drive shaft and the forward end of said propeller shaft, the center of said universal joint means coinciding with the pivot point about which said ball pivots relative to said ball socket; and

said propeller shaft carrier swinging laterally about a generally vertical steering axis that extends through said pivot point and vertically about a horizontal trim axis that extends through said pivot point.

5. Marine outdrive apparatus as claimed in claim 4 characterized in that

said steering means include starboard and port power-operated steering cylinders and plunger units having their rear ends pivotally connected to said propeller shaft carrier and their front ends universally pivotally secured to the opposite sides of said support casing when a horizontal line extending through the pivot point about which said ball pivots relative to said ball socket, said line being normal to the longitudinal axis of said drive shaft.

6. Marine outdrive apparatus as claimed in claim 4 or claim 5 characterized in that

said trim means includes a power-operated trim cylinder and plunger unit having its front end universally pivotally attached to the transom of said boat and its rear end pivotally secured to the intermediate portion of said propeller shaft carrier.

7. Marine outdrive apparatus as claimed in any one of the preceding claims characterized in that the rear portion of said propeller shaft carrier is provided with upper and lower fins, and said upper fin supports a cavitation plate.