U.S. patent number 3,788,266 [Application Number 05/330,597] was granted by the patent office on 1974-01-29 for multi-powerhead outboard motor.
This patent grant is currently assigned to Outboard Marine Corporation. Invention is credited to Charles D. Strang.
United States Patent |
3,788,266 |
Strang |
January 29, 1974 |
MULTI-POWERHEAD OUTBOARD MOTOR
Abstract
Disclosed herein is an outboard motor comprising a lower unit
rigidly connected to the bottom of a drive shaft housing and
including a rotatably mounted propeller shaft supporting a
propeller, first and second engines respectively including first
and second crankshafts and respectively mounted to the top of the
drive shaft housing with the first and second crankshafts extending
at an acute angle to each other, first and second drive shafts
respectively drivingly connected to the first and second
crankshafts and respectively extending in the drive shaft housing
and in the lower unit in co-axial relation to the first and second
crankshafts, and gearing in the lower unit drivingly connecting the
first and second drive shafts to the propeller shaft.
Inventors: |
Strang; Charles D. (Lake
Forest, IL) |
Assignee: |
Outboard Marine Corporation
(Waukegan, IL)
|
Family
ID: |
23290466 |
Appl.
No.: |
05/330,597 |
Filed: |
February 8, 1973 |
Current U.S.
Class: |
440/75;
60/716 |
Current CPC
Class: |
F02B
61/045 (20130101); F02B 73/00 (20130101); B63H
20/20 (20130101); B63H 23/10 (20130101) |
Current International
Class: |
B63H
23/10 (20060101); B63H 23/00 (20060101); F02B
61/04 (20060101); F02B 61/00 (20060101); F02B
73/00 (20060101); B63h 021/26 () |
Field of
Search: |
;115/12 A,17/
;115/18R,18A,34R,35 ;123/195P,51BA ;74/661 ;60/97R |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Reger; Duane A.
Assistant Examiner: Sotelo; Jesus D.
Attorney, Agent or Firm: Robert E. Clemency et al.
Claims
I claim:
1. An outboard motor comprising a propulsion unit including a drive
shaft housing, a lower unit rigidly connected to the bottom of said
drive shaft housing and including a rotatably mounted propeller
shaft supporting a propeller, first and second engines respectively
including first and second crankshafts and being respectively
mounted to the top of said drive shaft housing with said first and
second crankshafts extending at an acute angle to each other, first
and second drive shafts respectively drivingly connected to said
first and second crankshafts and respectively extending in said
drive shaft housing and in said lower unit in co-axial relation to
said first and second crankshafts, and gearing in said lower unit
drivingly connecting said first and second drive shafts to said
propeller shaft and means adapted to be connected to a boat hull
and connected to said propulsion unit to afford vertical and
horizontal swinging movement of said propulsion unit relative to
the boat hull.
2. An outboard motor in accordance with claim 1 wherein said first
and second engines respectively include a plurality of cylinders
extending in parallel relation to one another.
3. An outboard motor in accordance with claim 2 wherein all of said
cylinders have axes extending parallel to said propeller shaft and
said cylinders of said first engine extend forwardly of said first
crankshaft and wherein said cylinders of said second engine extend
rearwardly of said second crankshaft.
4. An outboard motor in accordance with claim 2 wherein said first
and second engines are laterally spaced from each other.
5. An outboard motor in accordance with claim 2 wherein all of said
cylinders have axis extending laterally to said propeller shaft and
said cylinders of said first engine extend laterally from said
first crankshaft in one direction and said cylinders of said second
engine extend laterally from said second crankshaft in the
direction opposite from said one direction.
6. An outboard motor in accordance with claim 2 wherein said first
and second engines are spaced from each other in the direction of
the axis of said propeller shaft.
7. An outboard motor in accordance with claim 1 wherein said first
and second crankshafts extend at an acute angle to each other when
viewed in a vertical plane perpendicular to said propeller
shaft.
8. An outboard motor in accordance with claim 1 wherein said first
and second crankshafts extend in parallel relation to each other
when viewed in a vertical plane parallel to said propeller
shaft.
9. An outboard motor in accordance with claim 1 wherein said first
and second crankshafts extend at an acute angle to each other when
viewed in a vertical plane extending parallel to said propeller
shaft.
10. An outboard motor in accordance with claim 1 wherein said first
and second crankshafts extend in a common vertical plane containing
said propeller shaft.
11. An outboard motor in accordance with claim 1 wherein said first
and second crankshafts counter rotate.
12. An outboard motor in accordance with claim 1 wherein said first
and second crankshafts rotate in the same rotative direction.
13. An outboard motor propulsion unit including a drive shaft
housing, a lower unit rigidly connected to the bottom of said drive
shaft housing and including a rotatably mounted propeller shaft
supporting a propeller, first and second engines mounted to the top
of said drive shaft housing in laterally spaced relation to each
other and respectively including respective first and second
crankshafts, and respective pluralities of cylinders extending in
parallel relation to one another in parallel relation to said
propeller shaft with said cylinders of said first engine extending
forwardly of said first crankshaft and said cylinders of said
second engine extending rearwardly of said second crankshaft, first
and second drive shafts respectively drivingly connected to said
first and second crankshafts and respectively extending in said
drive shaft housing and in said lower unit in co-axial relation to
said first and second crankshafts, said first and second drive
shafts extending at an acute angle to each other when viewed in a
vertical plane perpendicular to said propeller shaft and extending
in parallel relation to each other when viewed in a vertical plane
parallel to said propeller shaft, and gearing in said lower unit
drivingly connecting said first and second drive shafts to said
propeller shaft.
14. An outboard motor propulsion unit in accordance with claim 13
wherein said first and second crankshafts counter rotate.
15. An outboard motor propulsion unit in accordance with claim 13
wherein said first and second crankshafts rotate in the same
rotative direction.
16. An outboard motor propulsion unit including a drive shaft
housing, a lower unit rigidly connected to the bottom of said drive
shaft housing and including a rotatably mounted propeller shaft
supporting a propeller, first and second engines respectively
rigidly mounted to the top of said drive shaft housing in spaced
relation to each other axially of said propeller shaft and
including respective first and second crankshafts extending at an
acute angle to each other, and respective pluralities of cylinders
extending in parallel relation to one another with said cylinders
of said first engine extending laterally from said first crankshaft
in one direction and said cylinders of said second engine extending
laterally from said second crankshaft in the direction opposite
from said one direction, first and second drive shafts respectively
drivingly connected to said first and second crankshafts and
respectively extending in said drive shaft housing and in said
lower unit in co-axial relation to said first and second
crankshafts, said first and second drive shafts extending in a
common vertical plane containing said propeller shaft and at an
acute angle to each other when viewed in a vertical plane extending
parallel to said propeller shaft, and gearing in said lower unit
drivingly connecting said first and second drive shafts to said
propeller shaft.
17. An outboard motor propulsion unit in accordance with claim 16
wherein said first and second crankshafts counter rotate.
18. An outboard motor propulsion unit in accordance with claim 16
wherein said first and second crankshafts rotate in the same
rotative direction.
Description
BACKGROUND OF THE INVENTION
The invention relates generally to outboard motors and more
particularly to outboard motors including two engines. Examples of
prior patents disclosing outboard motors with two engines include
the U.S. Moran Pat. No. 2,737,143 issued Mar. 6, 1956 and the U.S.
Tenney Pat. No. 3,025,823 issued Mar. 20, 1962.
Examples of prior patents disclosing outboard motors with a single
oppositely acting engine including two spaced crankshafts include
the U.S. Bizet Pat. No. 1,707,897 issued Apr. 2, 1929, the U.S.
Stucke Pat. No. 2,781,749 issued Feb. 19, 1957 and the U.S.
Schimanckas Pat. No. 3,148,557 issued Sept. 15, 1964.
The foregoing patents employ either two drive shaft housings and
connected lower units as in the Moran and Bizet patents or a single
drive shaft housing and lower unit powered by an oppositely acting
engine as in the Stucke, Schimanckas and Tenney patents.
In both of the Stucke and Tenney patents, the crankshafts are
drivingly connected adjacent to the engine block. In Schimanckas,
parallel drive shafts extend from parallel crankshafts.
Attention is also directed to the U.S. Hult Pat. No. 1,165,803
issued Dec. 18, 1915.
All of the above constructions suffer various relative
disadvantages. For instance, the use of two drive shaft housings
and lower units is relatively expensive. In addition, the use of
two lower units increases the drag or resistance to travel through
the water. Use of gearing or other connections adjacent the engine
block, as for instance in the Tenney patent and in the Stucke
patent, serves to increase weight and expense and involves power
loss. Lubrication of such gearing is a further consideration
involving added cost, weight and complexity. Furthermore,
gear-boxes, such as are employed in the Tenney patent, interfere
with exhaust gas flow to the drive shaft housing and with exhaust
gas.
Use of a double acting engine, as disclosed particularly in FIG. 1
of the Schimanckas patent, serves to substantially increase the
fore and aft distance between the parallel drive shafts and thereby
to increase the lower unit wetted area with consequent increased
frictional resistance to travel through the water. All of the above
factors have previously indicated that more powerful outboard
motors could be most economically obtained by employing a single
engine of larger horsepower.
SUMMARY OF THE INVENTION
The invention provides an outboard motor including a single drive
shaft housing and connected lower unit, together with two separate
engines mounted to the top of the drive shaft housing with
respective crankshafts extending at an acute angle to each other
and connected to the upper end of respective co-axially extending
drive shafts which extend through the drive shaft housing and into
the lower unit and which, at their lower ends, are connected by
gearing to a single propeller shaft rotatably supported in the
lower unit.
In one embodiment, the engines are laterally spaced from each other
and include respective pluralities of cylinders having axes
extending in parallel relation to the propeller shaft. The engines
are oppositely facing, i.e., the cylinders of one engine extend
forwardly from the associated crankshaft and the cylinders of the
other engine extend rearwardly from the associated crankshaft. In
addition, the crankshafts and respectively connected drive shafts
extend in an acute angle to each other when viewed from a vertical
plane perpendicular to the propeller shaft and in parallel relation
to each other when viewed from a vertical plane parallel to the
propeller shaft.
In another embodiment, the engines are spaced in the fore and aft
direction, i.e., axially of the propeller shaft, and include
respective pluralities of cylinders having axes extending in
parallel relation to one another and in lateral relation to the
propeller shaft. The engines are oppositely facing, i.e., the
cylinders of one engine extend laterally from the associated
crankshaft in one direction and the cylinders of the other engine
extend laterally of the associated crankshaft in the opposite
direction. In addition, the crankshafts and the respectively
connected drive shafts extend in a plane common to the propeller
shaft and at an acute angle to each other when viewed from a
vertical plane in parallel relation to the propeller shaft.
One of the principal objects of the invention is the provision of a
multi-engine outboard motor having a single lower unit with a
minimum frontal area.
Another of the principal objects of the invention is the provision
of an outboard motor including a single drive shaft housing and a
pair of internal combustion engines mounted to the top of the drive
shaft housing in such manner as to facilitate exhaust gas tuning
and conventional discharge of exhaust gases through the drive shaft
housing.
Another of the principal objects of the invention is the provision
of a high horsepower outboard motor which is light in weight per
unit of horsepower, which is simple in design, economical to
construct, and which delivers maximum effective horsepower.
Other objects and advantages of the invention will become known by
reference to the following description, claims and accompanying
drawings.
THE DRAWINGS
FIG. 1 is a side elevational view, partially in section, of one
embodiment of an outboard motor incorporating various of the
features of the invention.
FIG. 2 is a transverse view, partially in section, of the outboard
motor shown in FIG. 1.
FIG. 3 is a schematic view of an alternate arrangement for
connecting the drive shafts and propeller shaft shown in FIGS. 1
and 2.
FIG. 4 is a side elevational view, partially in section, of a
second embodiment of an outboard motor incorporating various of the
features of the invention.
FIG. 5 is a transverse view, partially in section, of the outboard
motor shown in FIG. 4.
FIG. 6 is a schematic view of an alternate construction for
connecting the drive shafts and the propeller shaft shown in FIGS.
4 and 5.
Before explaining the invention in detail, it is to be understood
that the invention is not limited in its application to the details
of construction and arrangement of parts set forth in the following
general description or illustrated in the accompanying drawings,
since the invention is capable of other embodiments and of being
practiced or carried out in various ways. Also, it is to be
understood that the phraseology or terminology employed herein is
for the purpose of description and not of limitation.
GENERAL DESCRIPTION
Shown in FIGS. 1 and 2 is an outboard motor 11 including a
propulsion unit 13 comprising a single, hollow drive shaft housing
15 and a lower unit 17 rigidly connected to the lower end of the
drive shaft housing 15 and rotatably supporting a propeller shaft
19 carrying a propeller 21. Also included in the propulsion unit 13
are two generally identically constructed, internal combustion
engines 23 and 25, which are respectively rigidly secured to the
top of the drive shaft housing 15.
As is conventional practice, there is connected to the propulsion
unit 13 means adapted to be attached to a boat transom and
affording both vertical and horizontal swinging movement of the
propulsion unit 13 relative to the boat transom. While various
other arrangements can be employed, in the illustrated
construction, such means comprises a transom bracket 31 adapted to
be attached to the boat transom, and a swivel bracket 33 which is
pivotally connected to the transom bracket 31 about a horizontal
tilt axis 35 to afford vertical swinging movement therebetween and
which is pivotally connected to the propulsion unit 13 about a
steering axis 37 provided by a king pin 39.
Each of the engines 23 and 25 is of generally conventional
construction and can be of various multi-cylinder designs.
In the illustrated construction each engine 23 and 25 includes
three cylinders 41 each having associated therewith a spark plug 43
and an individual carburetor 45. In addition, the engines 23 and 25
include respective crankshafts 47 and 49 operatively connected with
pistons (not shown) respectively operable in the cylinders 41.
Respective fly wheels 51 are attached to the top of the respective
crankshafts 47 and 49.
In particular in accordance with the invention, the engines 23 and
25 are mounted with their crankshafts 47 and 49 in acute angular
relation to each other and, in the embodiment shown in FIGS. 1 and
2, in laterally spaced relation to each other and with one engine
facing forwardly, i.e, with the cylinders 41 extending forwardly
from the crankshaft 47 and with the other engine 25 extending
rearwardly, i.e., with the cylinders 41 extending rearwardly from
the crankshaft 49, and in parallel relation to the propeller shaft
19 and to the other cylinders 41. In order to facilitate engine
mounting in the desired arrangement, the upper end of the drive
shaft housing 15 is designed to provide two angularly oriented
mounting surfaces 55 and 57 which extend at an obtuse angle to each
other when viewed from in front, i.e., when viewed from a vertical
plane extending perpendicular to the propeller shaft 19.
Also in accordance with the invention, first and second drive
shafts 61 and 63 are respectively suitably coupled in any
conventional manner to the first and second crankshafts 47 and 49
and extend co-axially with the respective crankshafts 47 and 49
downwardly within the drive shaft housing 15 and into the lower
unit 17 for driving connection through suitable gearing 65 with the
propeller shaft 19. When viewed from the side, i.e., from a
vertical plane extending parallel to the propeller shaft 19, the
drive shafts 61 and 63 extend vertically in generally parallel
relation to each other and in adjacently spaced relation in the
fore and aft direction, and when viewed from the front, i.e., from
a vertical plane perpendicular to the propeller shaft 19, the drive
shafts 61 and 63 extend in acute angular relation to each other and
converge adjacent to the propeller shaft 19. Any suitable means can
be employed to rotatably support the drive shafts 61 and 63 in the
drive shaft housing 15 and in the lower unit 17.
As shown best in FIG. 2, the drive shaft housing 15 and lower unit
17 are generally of upwardly open "V" shape and neck-down to a
minimal frontal area in the vicinity immediately above the gearcase
portion 69 of the lower unit. Only the lower, relatively narrow
portion of the "V" shape configuration is normally immersed in
water during operation. Specifically, only that area of the lower
unit 17 located below the cavitation plate 67 is normally located
underwater during operation.
Various gearing arrangements can be used to connect the drive
shafts 61 and 63 to each other and to the propeller shaft 19. In
FIG. 1, two right angle bevel gears 71 and 73 spaced axially of the
propeller shaft 19 are pinned at 75 to the propeller shaft 19 for
common rotation therewith and are respectively in mesh with bevel
gears 77 and 79 respectively carried by the drive shafts 61 and 63.
In the arrangement shown in FIG. 1, the drive shafts 61 and 63 both
rotate in the same rotative direction.
Shown in FIG. 3 is another gearing arrangement for drivingly
connecting the drive shafts 61 and 63 to the propeller shaft 19. In
the FIG. 3 arrangement, a compound gear 81 is mounted in the lower
unit 17 in co-axial relation to the propeller shaft 19 and for
relative rotation therebetween. The compound gear 81 includes
oppositely facing right angle bevel gears 83 and 85 in respective
engagement with the bevel gears 77 and 79 fixed to the respective
drive shafts 61 and 63. In addition, a second right angle bevel
gear 87 is also rotatably mounted by the lower unit in co-axial
relation to the propeller shaft 19 and for relative rotation
therebetween. The second bevel gear 87 is located aft of the
compound gear 81 and is in mesh with the bevel gear 77 on the aft
drive shaft 61.
Mounted on the propeller shaft 19 for movement axially thereof and
for common rotation therewith is a dog clutch 89 which is
selectively engageable with the bevel gears 83 and 87 so as to
afford forward, neutral, and reverse drive connection of the drive
shafts 61 and 63 to the propeller shaft 19. Various arrangements
can be employed to shift the clutch dog 89. Connection of both of
the drive shafts 61 and 63 to the compound gear 81 serves to
interconnect the engines 23 and 25 one to another and, as a result,
the drive shafts 61 and 63 counter rotate with respect to each
other.
Shown in FIGS. 4 and 5 is another embodiment of an outboard motor
111 embodying various of the features of the invention. As in the
outboard motor 11 shown in FIGS. 1 and 2, the outboard motor 111
includes a propulsion unit 113 which is connected to a swivel
bracket 133 for horizontal steering therebetween and, in turn, the
swivel bracket 133 is connected to a transom bracket 131 for
vertical swinging movement relative thereto.
Also as in the outboard motor 111, the propulsion unit 113 includes
a hollow drive shaft housing 115 and a lower unit 117 which is
rigidly attached to the bottom of the drive shaft housing 115 and
which rotatably supports a propeller shaft 119 carrying a propeller
121. In addition, the propulsion unit 113 includes two generally
identical engines 123 and 125 each having a plurality of cylinders
141 with associated spark plugs 143 and carburetors 145. Still
further, the engines 123 and 125 respectively include crankshafts
147 and 149 which are operably connected through pistons (not
shown) in the cylinders 141.
As in the outboard motor 11, the engines 123 and 125 are spaced
from each other and are rigidly mounted to the upper end of the
drive shaft housing 115 so that the crankshafts 147 and 149 extend
at an acute angle to each other. However, as distinguished from the
construction of the outboard motor 11, in the outboard motor 111,
the engines 123 and 125 are located in fore and aft spaced relation
to each other, i.e., are spaced axially of the propeller shaft 119,
with the forward engine 123 facing to one side, i.e., with the
cylinders 141 extending laterally from the crankshaft 147 to the
left as shown in FIG. 5, and with the cylinders 141 of the aft
engine 125 extending laterally from the crankcase 149 to the other
side, i.e., to the right in FIG. 5. Thus, in the embodiment shown
in FIGS. 4 and 5, the cylinder axes extend laterally whereas in the
embodiment shown in FIGS. 1 and 2 the cylinders axes extend fore
and aft.
In order to mount the engines 123 and 125 as above described, the
drive shaft housing 115 includes, at the upper end thereof, two
fore and aft angularly related mounting areas 155 and 157 to which
the engines 123 and 125 are respectively rigidly connected.
Extending through the drive shaft housing 115 and into the lower
unit 119 are fore and aft drive shafts 161 and 163 which extend
co-axially from and are suitably drivingly coupled to the fore and
aft crankshafts 147 and 149. At their lower ends, the drive shafts
161 and 163 are drivingly connected to the propeller shaft 119 by
suitable gearing 165. While other arrangements are possible, in the
construction illustrated in FIG. 4 and 5, the propeller shaft 119
has pinned thereto a compound gear 181 having fore and aft facing
bevel gears 183 and 185 which are respectively meshed with bevel
gears 177 and 179 on the respective drive shafts 161 and 163.
As can be seen from FIGS. 4 and 5, the drive shafts 161 and 163
extend in co-planar relation with each other and with the propeller
shaft 119 and in fore and aft spaced relation. When seen from the
side, i.e., from a vertical plane parallel to the propeller shaft
119, the drive shafts 161 and 163 extend in acute relation to each
other and converge in the downward direction. Various suitable
bearing means can be employed to rotatably support the drive shafts
161 and 163 in the drive shaft housing 115 and in the lower unit
117.
As can be seen especially in FIG. 5, the lower unit has a
relatively narrow frontal area between the cavitation plate 167 and
the gear case 169.
Shown in FIG. 6 is another gearing arrangement including a
reversing transmission. The gearing arrangement is similar to that
disclosed in FIGS. 4 and 5 except that the compound gear 181 is not
pinned to the drive shaft 119 and is rotatable relative thereto and
supported from the lower unit 117 in co-axial relation to the
propeller shaft 119. Also included in the gearing arrangement shown
in FIG. 6 is a second bevel gear 187 which is mounted in spaced
relation aft of the compound gear 181 and in co-axial relation to
the propeller shaft 119 for relative rotation therebetween. The
second bevel gear 187 is smaller than the rearwardly facing gear
185 on the compound gear 181 and is also in mesh with the bevel
gear 179 on the after drive shaft 163.
Located between the bevel gears 183 and 187 is a clutch dog 189
which is slidable axially on the propeller shaft 119 and which
rotates in common with the propeller shaft 119 and which is
selectively engageably with the bevel gears 185 and 187 to provide
forward, neutral, and reverse drive conditions. Various
arrangements can be employed to shift the dog clutch between its
various positions.
In the gearing arrangement disclosed in FIGS. 4 through 6, the
drive shafts 161 and 163 counter rotate. If desired, an arrangement
similar to that shown in FIG. 1 could be employed if it is desired
to have the drive shafts 161 and 163 rotate in the same
direction.
Both of the disclosed embodiments incorporate two separate and
generally identical engines which are separately and rigidly
mounted in spaced and angular relation to each other on the top of
a drive shaft housing. Such arrangement allows exhaust gas
discharge through the drive shaft housing using conventional
techniques and without interference from gearing located above or
within the drive shaft housing. In particular, tuning tubes can be
employed so as to improve engine performance and exhaust gas
discharge can be either through a snout 200 as shown in FIGS. 1 and
4 or through a propeller hub as is also conventional.
It is noted that one-half of the total horsepower of the outboard
motor, i.e., the output of each engine, is directly transmitted
from the applicable engine to the propeller shaft through
independent drive shafts and through bevel gearing which is smaller
than if the entire horsepower output of the outboard motor were
transmitted through a single set of bevel gears. Thus,
notwithstanding large horsepower delivery, the frontal area of the
lower unit can be relatively small so as to avoid power losses due
to water resistance.
Because the engines of the embodiment of FIGS. 1 and 2 are
reversely oriented, and because the engines in the embodiment of
FIGS. 4 and 5 are supported in angular relation to each other (as
seen best in FIG. 4) the drive shafts can enter the lower unit in
relatively adjacent relation to each other in the fore and aft
direction, and thereby avoid excessive length in the fore and aft
dimension of the lower unit.
Connection of the drive shafts to each other in the lower unit
either through a compound gear (see FIGS. 3, 4 and 6) or through a
propeller shaft (see FIG. 1) serves to avoid problems associated
with equalizing power delivery through a double drive shaft
arrangement powered by a single engine.
In general, the disclosed constructions provide an outboard motor
or relatively high horsepower output with a relatively small lower
unit frontal area and with minimum weight, economic cost, and power
loss, and with freedom from various of the complexities found in
the prior art.
In addition, the employment of relatively long drive shafts which
have a low torsional frequency, serves to reduce or substantially
eliminate the possibility of developing critical vibrations in the
drive train of the outboard motor.
Various of the features of the invention are set forth in the
following claims.
* * * * *