Driving and steering mechanism for boats

The mechanism comprises, in combination, a main power shaft, a propeller shaft, a housing for the propeller shaft, a disc-type constant velocity joint (Rzeppa joint) operatively connecting the main power shaft and the propeller shaft, and a tillar arm operatively connected to the housing of the propeller shaft. The Rzeppa joint enables the axial angular displacemnt of the propeller shaft relative to the power shaft to be altered in all directions. Thus if the boat encounters a submerged obstacle, the propeller shaft and its housing can automatically ride over the obstacle and avoid damage or entanglement. Preferably the system also includes a latch and stop assembly that enables the operator to pre-set the vertical angular displacement of the propeller shaft relative to the power shaft in various positions, e.g., (1) uplock (for overland transport and starting). (2) shallow drive (for travelling through swamps where the water is only a few inches deep). (3) normal running (where the propeller is somewhat more deeply immersed in the water), and (4) full depth. In positions (2) and (3) the propeller shaft can be moved laterally and upwardly but not downwardly to the next lower operating position unless a release on the tillar arm is actuated by the operator. A novel hollow funnel-shaped coupling device especially adapted for connecting the disc-type constant velocity joint to the rotatable power shaft is also described. The coupling device features a unique way of lubricating the constant velocity joint from the interior of the coupling device. Also described is a novel latch and stop mechanism additionally adapted to serve as a swivel joint.

TECHNICAL FIELD 
This invention relates to a novel and highly efficient mechanical system 
for steering and propelling power driven boats. 
BACKGROUND 
Generally speaking, there are two widely divergent types of service 
conditions under which a boat may be operated. One type of service 
involves operation in relatively deep water (lakes, rivers, etc.) where 
rarely, if ever, is contact with submerged objects of concern. The other 
type of service is largely but not exclusively encountered in swampy 
regions such as exist in Southern Louisiana, Southern Florida, and 
elsewhere. In this type of service the water is oftentimes extremely 
shallow, sometimes not more than few inches deep. And such shallow waters 
are often muddy, clogged with vegetation, and replete with submerged 
obstacles such as tree logs or branches, mud bars, and the like. For such 
service flat bottom boats are normally employed. 
Heretofore two different approaches have been taken in providing propulsion 
and steering systems for use under these severe shallow water service 
conditions. One approach involves mounting the engine in a tilted position 
within the flat bottom boat so that the power and propeller shaft extends 
downwardly and rearwardly through the bottom of the boat where it is held 
in place under the rear of the boat at a relatively shallow depth by a 
strut bearing positioned in front of the propeller. The rudder is 
separately mounted on the transom at the rear of the boat. The other 
approach involves use of a highly elongated propeller shaft (e.g., 5 or 6 
feet in length) which is coupled to the engine drive shaft by means of a 
standard universal joint. With this system the engine is mounted over the 
transom of the boat and because of the long propeller shaft used, the 
entire unit including the engine pivots when the shaft or a shoe on the 
shaft encounters a submerged obstacle. 
THE INVENTION 
In accordance with this invention a new mechanical system for propelling 
and steering power driven boats is provided. These systems are extremely 
versatile as they can be used to drive and steer boats in relatively deep 
water or in the extremely shallow waters such as are encountered in 
swamps, bayous and savannahs. The systems are durable, simple in design, 
compact, easy to operate, and highly reliable during use even under the 
most severe shallow water conditions of the type referred to above. What's 
more, they are relatively inexpensive, and require very little 
maintenance. 
The features and advantages of this invention are accomplished by providing 
in combination, a main power shaft, a propeller shaft, a housing for the 
propeller shaft, a disc-type constant velocity joint operatively 
connecting the main power shaft and the propeller shaft, and a tillar arm 
operatively connected to the housing of the propeller shaft for adjusting 
the axial displacement of the propeller shaft relative to the axis of the 
main power shaft. Preferably the mechanism further includes latch and stop 
catch means for adjusting the vertical angle of displacement between the 
propeller shaft and the main power shaft. As will be apparent hereinafter, 
in a particularly preferred mode of construction such latch and stop means 
are further characterized in that they enable the propeller shaft, aligned 
in preselected vertical angular displacement relative to the power shaft, 
to be moved laterally for steering purposes while permitting the propeller 
shaft to be vertically displaced upwardly as soon as it comes in contact 
with a submerged obstacle such as a tree log or stump, mud bar, or the 
like. 
In still another embodiment of this invention the latch and stop means are 
further characterized in that (a) they enable the propeller shaft to be 
aligned in a plurality of preselected vertical angular displacement 
positions relative to the power shaft, in that (b) they enable the 
propeller shaft, aligned in at least one of the preselected vertical 
angular displacement positions relative to the power shaft, to be moved 
laterally and upwardly but not downwardly from said preselected vertical 
angular displacement, and in that (c) they include a manually actuatable 
release enabling the propeller shaft to be moved upwardly or downwarly 
within the range of said preseleced vertical angular displacement 
positions. 
Yet another embodiment of this invention is the provision of a novel hollow 
funnel-shaped coupling device especially adapted for connecting the 
disc-type constant velocity joint to the rotatable power shaft. The 
coupling device also features a unique way of lubricating the constant 
velocity joint from the interior.

In the Drawings, like numerals represent like parts among the several 
views. 
DESCRIPTION OF PREFERRED EMBODIMENTS 
In the preferred form depicted, the mechanism mounted on boat 10 comprises 
main power shaft 20, propeller shaft 30, propeller 32, guide tube 34, 
disc-type constant velocity joint 40 interposed between and connecting 
shafts 20 and 30, tillar arm 50, and connector arm 60 extending between 
tillar arm 50 and guide tube 34. Propeller 32 is tightly but detachably 
secured to propeller shaft 30 by means of propeller nut 65. Tube 34 serves 
as a housing for propeller shaft 30. Shaft 30 is rotatably supported 
within tube 34 by means of forward shaft bushing 31 and rearward shaft 
bushing 33. Shaft seals and shaft packing (not shown) are preferably 
inserted to the rear of bushing 33 to provide a liquid tight seal between 
the back end of tube 34 and shaft 30. Power is supplied to shaft 20 by 
engine or motor 12. Shaft 20 is encased in transom tube 22 which extends 
through the transom 14 of the boat. Constant velocity joint 40 is encased 
within transom tube 22 and flexible boot 45, and the interior of transom 
tube 22 and boot 45 is filled to an appropriate level with lubricating oil 
(not shown) which is added via filler tube 25. A metal strap-type clamp 
(not shown) of appropriate diameter is positioned and tightened around the 
exterior of boot 45 to seal the forward portion of boot 45 against transom 
tube 22, and another such clamp 47 of smaller diameter is positioned and 
tightened around the exterior of the back end portion of boot 45 to seal 
it against a forward portion of guide tube 34. These clamps not only 
secure the boot in place, but prevent the leakage of oil from the boot and 
the intake of water into the boot. The filler tube cap (not shown) is 
preferably fitted with a dip stick for measuring the level of oil in this 
combination power transmission and steering system. 
Secured to guide tube 34 are skeg 38 and antiventilation plate 39. It will 
be noted that skeg 38 is in the shape of an inverted inclined plane to 
enable the skeg to ride over submerged obstacles. In so doing, skeg 38 
elevates the entire assembly comprising guide tube 34, propeller shaft 30, 
and propeller 32 and thereby keeps the assembly from striking or becoming 
embedded in the obstacle. And, constant velocity joint 40 makes this 
upward pivoting movement possible--the position of the engine or motor and 
its power shaft are not changed. Forward skeg 23 is mounted at the base of 
transom tube 22. 
Tillar arm 50 is of tubular contruction and is swivelly mounted on transom 
tube 22 by means of pivot bracket or arm 97 (which pivots around a 
horizontal axis) and pivot pin 54 (around the axis of which the tillar arm 
may be rotated) so that the tillar arm can be moved upwardly and 
downwardly as well as from side to side. Catch pin 51 is concentrically 
aligned with and slidably mounted within pivot pin 54 which in turn is 
mounted on pivot arm 97 and disposed within the lower end portion of 
tillar arm 50. While not essential, it is preferred to position a vertical 
cylindrical bushing (not shown) coaxially between pivot pin 54 and the 
lower portion of tillar arm 50, the bushing extending vertically along 
substantially the entire length of the pivot pin. The lower end portion of 
catch pin 51 is positioned and adapted to engage the down stop catch 70. 
The upper end portion of catch pin 51 has a cylindrical recess 52 into 
which is fitted catch pin spring 53 which is maintained under compression 
by a stop 99 or other restraining means within pivot pin 54. In this way 
spring 53 tends to apply a continuous downward force against catch pin 51 
to keep it in engagement with catch 70. 
Attached to catch pin 51 is catch pin cable 55 which extends along the 
interior of pivot pin 54 and along the interior of tillar arm 50 to down 
stop latch or release 56 in proximity to handle grip 57. Latch or release 
56 in the form depicted is composed of a cylinder 58 rotatable within the 
tillar arm and having a latch pin 59 extending through a notched slot 63 
in the tillar arm, the notched slot having a plurality of notches to 
accommodate pin 59 at different locations along the length of the tillar 
arm. Cable 55 is connected to cylinder 58 so that when pin 59 is moved out 
of a notch and a manual pulling force toward the handle grip 57 is applied 
to pin 59 by the boat operator, the cable applies the pulling force to 
catch pin 51 in an upward direction thereby overcoming the downward force 
exerted by spring 53. As a consequence of this upward pulling force, catch 
pin 51 can be disengaged from the down stop catch 70 so that the angle of 
displacement of propeller shaft 30 relative to power shaft 20 can be 
adjusted by moving tillar arm upwardly or downwardly to a position in 
which catch pin 51 will engage a different portion of down stop catch 70. 
At this point pin 59 is moved into the appropriate notch and the pulling 
force on release 56 is released so that spring 53 forces catch pin 51 into 
the desired stop position on down stop catch 70. For example by moving 
catch pin 51 in the manner described from its position shown in FIG. 6 to 
the next adjacent segment to the right on catch 70, the vertical alignment 
between propeller shaft 30 to power shaft 20 can be changed from a 
position in which the propeller is in a very shallow depth in the water to 
a position in which the propeller shaft extends more deeply in the water, 
an operation which would normally be carried out when proceeding from very 
shallow water to somewhat deeper water. Conversely, by moving catch pin 51 
from its position shown in FIG. 6 to the next adjacent segment to the left 
on catch 70, the vertical alignment between propeller shaft 30 to power 
shaft 20 can be changed from the shallow operating position to a position 
in which the propeller shaft extends upwardly above the surface of the 
water (as in FIG. 4). 
A feature of the preferred catch pin-down stop catch mechanism just 
described is is its automatic self-adjustability in the event the 
propeller shaft encounters a submerged obstruction. More particularly, if 
a boat, travelling in shallow water with its propeller shaft aligned with 
the power shaft (as in FIG. 3) passes over a submerged object that is 
impacted by skeg 38, the preferred catch pin-down stop catch mechanism 
described above does not prevent upward pivoting of the propeller shaft 
and its housing. Thus the propeller shaft and its housing are free to 
pivot upwardly and thereby ride over the top of the submerged object. Once 
the object is cleared, the catch pin-down stop catch mechanism of the type 
described allows the propeller shaft 30 to rotate downwardly to its 
original depth, but no further (unless the operator uses the release 56 to 
change the setting of the vertical angular displacement of the propeller 
shaft relative to the power shaft). 
It will also seen that the preferred catch pin-down stop catch mechanism of 
the device depicted in the Drawings enables the propeller shaft to be 
aligned in a plurality of preselected vertical angular displacement 
positions relative to the power shaft. In the form depicted in FIG. 6 
there are four such positions, namely: 
(1) an uplock position in which the propeller shaft extends upwardly above 
the horizontal (note FIG. 2), 
(2) a shallow drive position wherein the propeller shaft is displaced 
upwardly from the axis of the power shaft so that the propeller is 
immersed slightly below the surface of the water; 
(3) a normal running position in which the propeller shaft and power shaft 
are linearly aligned (when viewed from the side--note FIG. 3) so that the 
propeller is immersed somewhat more deeply below the surface of the water 
to an optimum running depth for the boat in use; and 
(4) a full depth position in which the propeller shaft extends downwardly 
from the power shaft even more deeply into the water. 
In each of positions (2) and (3) the propeller shaft can be moved laterally 
and upwardly by tillar arm 50, but stop 52 prevents its downward movement 
from that preselected position. However by manually actuating release 56, 
the position of the propeller shaft relative to the the power shaft can be 
readily adjusted from one position to another. Thus when transporting the 
boat overland and when starting the motor or engine, the system is 
normally in the uplock position. Once the motor or engine has been 
started, the system is adjusted by means of the release and tillar arm to 
the position desired for the situation at hand. This adjustability feature 
of this invention not only enables the operator to operate the boat in 
various types of service (shallow water, deep water, etc.) but it can be 
used to overcome severe obstacles. For example, if during operation in 
swampy or marshy terrain the boat becomes hung up on a stationary 
submerged obstacle, the full depth position can be used to lift the back 
of the boat upwardly over and off of the obstacle. 
One of the key features of the mechanisms of this invention, is the 
coupling together of power shaft 20 and propeller shaft 30 by means of 
disc-type constant velocity joint 40. Constant velocity joint 40 transmits 
rotary motion to shaft 30 via hardened steel balls 42 rolling in a grooved 
cage 44. Such joints--often referred to as Rzeppa constant velocity 
joints--are fully described for example in Rzeppa U.S. Pat. No. 3,187,520 
(all disclosure of which is incorporated herein by reference) and are 
available on the open market from different suppliers. They are designed 
for use in operating equipment in which the shafts are misaligned and so 
far as is known, constant velocity joints of this type have never been 
used in a system for driving and steering a boat. Particularly good 
results in the practice of this invention has been achieved using a small 
CON-VEL disc-type constant velocity joint available from Dana Corporation, 
Detroit, Mich., viz., model number R2-98-41X. 
Another feature of this invention, best seen in FIGS. 2 and 5 is the 
preferred manner by which the disc-type constant velocity joint 40 is 
secured to the power shaft 20. For this purpose, a coupling device 80 is 
utilized which comprises a hollow funnel-shaped body composed of a 
cylindrical tubular section 82, an outwardly tapering conical section 85 
which extends from tubular section 82, a wide ring-shaped mouth section 87 
which extends from conical section 85, and a plurality of hollow tubular 
scoops or flutes 89 which extend through the walls and outwardly from 
conical section 85. Tubular section 82 is adapted to attachably receive an 
end portion of power shaft 20. While other modes of attachment may be 
employed, in the preferred form depicted tubular section 82 has an outer 
end portion with a bore to slidably receive the end portion of shaft 20 
and an inner end portion with a bore of smaller diameter to coaxially 
accommodate means for threadably securing the device to the power shaft, 
such as a bolt or a machine screw and nut 91. The portion of the 
funnel-shaped body forming ring-shaped mouth section 87 has an annular 
recess adapted to attachably receive the constant velocity joint 40 which 
is secured to the body by means of bolts or machine screws 93. Flutes 89 
are adapted, when the device is rotated by the power shaft, to pick up 
lubricating oil from the interior of transom tube 22 and transmit 
lubricating oil into the interior of conical section 85. The centrifugal 
force created by the rotation causes lubricating oil to travel along the 
interior of the conical section and lubricate the constant velocity joint 
40 from the interior of the coupling device. Operation at all operating 
speeds (usually about 900 to about 3600 rpm) creates a centrifugal force 
sufficient to cause the lubricating oil to spew through the rotating 
constant velocity joint. 
Yet another feature of this invention, best seen in FIG. 6, is the unique 
latch and stop means that is employed in the preferred embodiments of this 
invention. While other suitable latch and stop systems may be employed, 
the system of FIG. 6 has the advantageous feature that it is additionally 
adapted to serve as a swivel joint. It will be seen from FIG. 6 that this 
preferred system comprises: 
(a) a generally inverted "U"-shaped pivotable bracket 97 having a 
horizontal segment extending between a pair of upstanding segments, the 
horizontal segment having an aperture therein, the arm being rotatable 
about a horizontal axis extending laterally through the lower portions of 
the upstanding segments; 
(b) a hollow cylindrical member (i.e., pivot pin 54) affixed to said 
horizontal segment so that the member is coaxial with and extends upwardly 
around said aperture; 
(c) a cylindrical latch member (i.e., catch pin 51) coaxially aligned and 
slidable within said cylindrical member and extending downwardly through 
said aperture; 
(d) a catch member 70 having a series of at least three linearly aligned 
stepped planar upper surfaces, the steps separating each planar upper 
surface from its adjacent upper planar surface, each of the outermost 
planar surfaces 70a, 70d being sloped downwardly away from its adjacent 
planar surface (70b and 70c, respectively) and the slope of each 
intervening planar surface (70b and 70c) being intermediate the slopes of 
its two adjacent planar surfaces, catch member 70 being disposed below and 
transverse to said horizontal segment so that as said bracket is pivoted 
about said axis, the base of latch member 51 linearly traverses said 
series of linearly aligned planar surfaces; and 
(e) means (e.g., spring 53) tending to force latch member 51 downwardly so 
that it abuts the upper planar surface of catch member 70 over which it is 
positioned by the pivotable bracket 97 and cylindrical member 54. 
As also shown in FIG. 6, it is particularly preferred that the elevation of 
the tops of said successive steps be progressively higher in one linear 
direction and progressively lower in the opposite direction. Thus the 
elevation of the top of the step (or riser) between planar surfaces 70b 
and 70c is higher than the elevation of the top of the step between planar 
surfaces 70a and 70b, but is lower than the elevation of the top of the 
step between planar surfaces 70c and 70d. The preferred system further 
includes means (e.g., cable 55 and latch or release 56) for pulling latch 
member 51 away from its abutted planar surface (70b in the position 
depicted in FIG. 6) so that bracket 97 is free to pivot on its horizontal 
axis. It will be noted that pivot pin 54 (the hollow cylindrical member) 
serves as a bearing around which tillar arm 50 can be rotated and against 
which forward and rearward force can be applied by tillar arm 50 to cause 
rotation or pivoting of bracket 97 around its horizontal axis. Thus pivot 
pin 54 is a focal point of the swivel action used in steering the boat and 
in adjusting the depth of propeller immersion to accommodate varying 
service conditions. 
This invention should not be confused with drive trains for propeller 
shafts that make use of a series of Cardan constant velocity joints. These 
systems are used primarily in deep water operation in high performance 
boats. Such systems are massive and complicated in design, and require 
large, high-horsepower engines for satisfactory operation. And, such 
systems are quite expensive. All of these drawbacks are avoided by use of 
a system of this invention. Additionally, the systems of this invention 
offer the advantages referred to above--a combination of advantages that 
has not been available to the art until now. 
It will also be noted the Drawings that unlike many prior mechanisms, the 
motor or engine 12 is mounted entirely within the perimeter of the boat 
10. An advantage of mounting the engine in this manner and positioning the 
main power shaft 20 so that it and its enveloping transom tube 22 extend 
through the transom 14 is that this provides a propulsion and steering 
system having a low profile with essentially all mechanical parts (except 
tillar arm 50 and the parts associated therewith such as release 56) 
located below the level (i.e., below the top) of the transom. This 
facilitates use of the tillar arm and provides the operator a clearer view 
of the position of the propeller relative to the surface of the water and, 
in the case of shallow water operation, the bed underlying the water as 
well. 
Besides affording the advantages referred to above, the systems of this 
invention have these additional advantageous features: 
(a) The driving and steering mechanism operates from a single pivot point 
which is universal in movement. 
(b) While the unit is in its normal drive position a minimum angle relative 
to the surface of the water may be achieved. (In the case of conventional 
flat bottom boats, angle alpha in FIG. 3 is preferably about 12 to 15 
degrees). This in turn makes possible maintenance of minimum drag and 
draft of the system during use. 
(c) The system is air-cooled thus allowing continuous operation under 
adverse conditions such as passage through mud or heavy vegetation, or the 
like. 
(d) Steering and propeller depth are manually manipulated and controlled 
very easily. 
(e) In the preferred systems, such as described above, total lubrication of 
all moving parts of the power drive train is accomplished simply and 
efficiently within a single closed system. 
(f) In the preferred systems, such as described above, weeds or other 
vegetation do not become excessively entangled on the unit--such systems 
are virtually weed-proof in design and operation. 
As this invention is susceptible of considerable variation, the forms and 
embodiments hereinbefore described being merely illustrative of preferred 
embodiments thereof, it is not intended that this invention be limited 
except within the spirit and scope of the following claims.