U.S. patent number RE32,620 [Application Number 06/774,661] was granted by the patent office on 1988-03-08 for lubricating system for an outboard engine.
This patent grant is currently assigned to Sanshin Kogyo Kabushiki Kaisha, Yamaha Hatsudoki Kabushiki Kaisha. Invention is credited to Tomio Iwai.
United States Patent |
RE32,620 |
Iwai |
March 8, 1988 |
Lubricating system for an outboard engine
Abstract
An improved lubricating system for a two-cycle outboard motor
having a vertically extending crankshaft. The lubricating system
employs a crankshaft driven pump and circulating system that
permits pressure lubricating without necessitating elongation of
the crankshaft or engine. The engine is enclosed within a cowling
and an oil sump is conveniently located within the cowling and is
accessible through a cover door of the cowling for replenishment of
the oil supply without removal of the cowling.
Inventors: |
Iwai; Tomio (Hamamatsu,
JP) |
Assignee: |
Sanshin Kogyo Kabushiki Kaisha
(both of, JP)
Yamaha Hatsudoki Kabushiki Kaisha (both of,
JP)
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Family
ID: |
14133412 |
Appl.
No.: |
06/774,661 |
Filed: |
September 11, 1985 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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281418 |
Jul 8, 1981 |
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Reissue of: |
528996 |
Sep 2, 1983 |
04493661 |
Jan 15, 1985 |
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Foreign Application Priority Data
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Jul 12, 1980 [JP] |
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55-95282 |
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Current U.S.
Class: |
440/77; 123/195P;
123/196R; 123/196W; 440/88L; 440/88R |
Current CPC
Class: |
F02B
61/045 (20130101); F02B 75/20 (20130101); F02B
75/007 (20130101); F02B 2075/1808 (20130101); F02B
2075/025 (20130101) |
Current International
Class: |
F02B
75/20 (20060101); F02B 61/00 (20060101); F02B
75/00 (20060101); F02B 61/04 (20060101); F02B
75/02 (20060101); F02B 75/18 (20060101); B63H
021/26 () |
Field of
Search: |
;440/76,77,88,900
;123/73AD,65R,196R,196CP,195C,195P,198E,65B,7R,196M,196W,198C
;180/205 ;244/135R |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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315008 |
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May 1974 |
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AT |
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12032 |
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Nov 1972 |
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FR |
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Primary Examiner: Peters, Jr.; Joseph F.
Assistant Examiner: Avila; Stephen P.
Attorney, Agent or Firm: Beutler; Ernest A.
Parent Case Text
This application is a continuation of application Ser. No. 281,418,
filed July 8, 1981, now abandoned.
Claims
I claim:
1. In a lubricating system for a two-cycle, crankcase compression
internal combustion engine having a cylinder block, a cylinder head
affixed to said cylinder block, a crankshaft supported for rotation
within a crankcase affixed to said cylinder block about a
vertically extending axis by at least vertically spaced upper
bearing means and lower bearing means, the improvement comprising
an oil supply tank mounted externally of said cylinder head,
cylinder block and crankcase, oil pump means supported externally
of said cylinder head, cylinder block and crankcase and driven
directly by said crankshaft, means for delivering oil from said
external oil supply tank to said oil pump means and conduit means
extending from said oil pump means to at least said upper bearing
means for positively lubricating said upper bearing means.
2. A lubricating system as set forth in claim 1, wherein the upper
bearing means and the lower bearing means journal the crankshaft by
means of spaced main bearing portions separated by a throw, and
means for providing for oil communication from the upper main
bearing means to the crankshaft throw for lubricating said throw
from oil return from said upper main bearing means.
3. A lubricating system as set forth in claim 1, wherein the
cylinder block has a pair of cylinders one positioned above the
other and the crankcase has separate sealed crankcase portions
associated with each of said cylinders, said upper bearing means
being associated with the .[.upermost.]. .Iadd.uppermost
.Iaddend.of said sealed crankcase portions, said oil pump means
being driven within the lowermost of said crankcase chambers.
4. A lubricating system as set forth in claim 3, wherein the upper
bearing means and the lower bearing means journal the crankshaft by
means of spaced main bearing portions separated by a throw, and
means for providing for oil communication from the upper main
bearing means to the crankshaft throw for lubricating said throw
from oil return from said upper main bearing means.
5. A lubricating system as set forth in claim 3, wherein the engine
is contained within an outer cowling and comprises the power unit
of an outboard motor and wherein the external oil supply tank is
supported within said cowling for supplying oil to said oil
pump.
6. A lubricating system as set forth in claim 5, further including
means in the cowling for permitting replenishing of oil in the oil
tank without requiring removal of the cowling.
7. A lubricating system as set forth in claim 6, wherein the tank
is supplied with a removable fill cap and the means for permitting
replenishing comprises an access door in the cowling that permits
access to the fill cap.
8. A lubricating system as set forth in claim 7, wherein the fill
cap is on the top of the tank and the access door is in the
uppermost portion of the cowling.
9. A lubricating system as set forth in claim 8, wherein the access
door is pivotally supported by the cowling for movement between an
open position and a closed position.
10. A lubricating system as set forth in claim 1 wherein the oil
pump means includes an oil pump drive shaft driven by the
crankshaft and extending at right angles to .Iadd.a plane
containing .Iaddend.the crankshaft rotational axis and to the axis
of the associated cylinder bore.
11. A lubricating system as set forth in claim 10 wherein the
cylinder block has a plurality of cylinders and the oil pump drive
shaft is disposed between the lowermost cylinder and the cylinders
lying above it.
12. In a lubricating system for a two-cycle, crankcase compression
internal combustion engine having a cylinder block, a cylinder head
affixed to said cylinder block, a crankshaft supported for rotation
about a vertically extending axis within a crankcase affixed to
said cylinder block, a cylinder bore formed in said cylinder block
and extending substantially perpendicularly to said vertically
extending axis, a piston reciprocally supported in said cylinder
bore, and connecting rod means operatively connecting said piston
to said crankshaft for driving said crankshaft, the improvement
comprising an oil pump positioned externally of said crankcase and
said cylinder block for lubricating portions of said engine, said
oil pump having a drive shaft extending perpendicularly to .Iadd.a
plane containing .Iaddend.said crankshaft axis and to said cylinder
bore axis and driven by said crankshaft.
13. A lubricating system as set forth in claim 12 wherein the
cylinder block has a plurality of cylinder bores having their axes
spaced vertically from each other and extending horizontally and
pistons each connected to the crankshaft by connecting rods.
14. A lubricating system as set forth in claim 13 wherein the oil
pump drive shaft is disposed on the upper side of the lowermost
connecting rod.
15. A lubricating system as set forth in claim 12 wherein the means
for driving the oil pump drive shaft comprises a gear affixed to
said oil pump drive shaft and enmeshed with a gear affixed to the
crankshaft.
16. In a lubricating system for a two-cycle outboard motor having
an engine and a surrounding cowling adapted to be carried at the
upper end of a drive shaft housing, the improvement comprising an
oil supply tank separate from said engine supported within said
cowling above said drive shaft housing for supplying oil to the
engine lubricating system and means in said cowling for permitting
replenishment of the oil in said oil tank without requiring or
removing said cowling.
17. An outboard motor as set forth in claim 16 wherein the means
for permitting the replenishing of the oil tank includes an access
door in the cowling.
18. An outboard motor as set forth in claim 17 wherein the tank is
positioned at least in part above the engine and is supplied with a
removable fill cap and the access door permits access to the fill
cap.
19. An outboard motor as set forth in claim 18 wherein the fill cap
is on the top of the tank and the access door is in the uppermost
portion of the cowling.
20. An outboard motor as set forth in claim 19 wherein the access
door is pivotally supported by the cowling for movement between an
open position and a closed position. .Iadd.
21. In a lubricating system for a two-cycle, crankcase compression
internal combustion engine having a cylinder block, a cylinder head
affixed to said cylinder block, a crankshaft supported for rotation
about a vertically extending axis within a crankcase affixed to
said cylinder block, a cylinder bore formed in said cylinder block
and extending substantially perpendicularly to said vertically
extending axis, a piston reciprocally supported in said cylinder
bore, and connecting rod means operatively connecting said piston
to said crankshaft for driving said crankshaft, the improvement
comprising an oil pump positioned externally of said crankcase and
said cylinder block for lubricating portions of said engine, said
oil pump having a drive shaft extending perpendicularly to a plane
containing said crankshaft axis and driven by said crankshaft and
means for delivering oil to said engine for its lubrication.
.Iaddend. .Iadd.22. A lubricating system as set forth in claim 21
wherein the cylinder block has a plurality of cylinder bores having
their axes spaced vertically from each other and extending
horizontally and pistons each connected to the crankshaft by
connecting rods. .Iaddend. .Iadd.23. A lubricating system as set
forth in claim 22 wherein the oil pump drive shaft is disposed
above the lowermost connecting rod. .Iaddend. .Iadd.24. A
lubricating system as set forth in claim 21 wherein the means for
driving the oil pump drive shaft comprises a gear affixed to said
oil pump drive shaft and enmeshed with a gear affixed to the
crankshaft. .Iaddend.
.Iadd.25. In a lubricating system for a two-cycle crankcase
compression internal combustion engine having a cylinder block, a
cylinder head affixed to said cylinder block, a crankshaft
supported for rotation within a crankcase affixed to said cylinder
block about a vertically extending axis by at least vertically
spaced upper bearing means and lower bearing means, the improvement
comprising an oil supply tank mounted externally of said cylinder
head, cylinder block and crankcase, oil pump means supported
externally of said cylinder head, cylinder block, oil supply tank
and crankcase and driven directly by said crankshaft by a gear
affixed for rotation to said crankshaft and an intermeshing gear
affixed to a drive shaft of said oil pump means, means for
delivering oil from said external oil supply tank to said oil pump
means and conduit means extending from said oil pump means to
deliver oil to said engine for its lubrication. .Iaddend. .Iadd.26.
In a lubricating system as set forth in claim 25 wherein the engine
is contained within an outer cowling and comprises the power unit
of an outboard motor and wherein the external oil supply tank is
supported within said cowling for supplying oil to said oil pump.
.Iaddend. .Iadd.27. In a lubricating system as set forth in claim
26 further including means in the cowling for permitting
replenishing of oil in the oil tank without requiring removal of
the cowling. .Iaddend. .Iadd.28. In a lubricating system as set
forth in claim 27 wherein the tank is supplied with a removable
fill cap and the means for permitting replenishing comprises an
access door in the cowling that permits access
to the fill cap. .Iaddend. .Iadd.29. In a lubricating system as set
forth in claim 28 wherein the fill cap is on the top of the tank
and the access door is in the uppermost portion of the cowling.
.Iaddend. .Iadd.30. In a lubricating system as set forth in claim
29 wherein the access door is pivotally supported by the cowling
for movement between an open position and a closed position.
Description
BACKGROUND OF THE INVENTION
This invention relates to an outboard engine and more particularly
to an .[.improve.]. .Iadd.improved .Iaddend.lubricating system for
such an engine.
It has been proposed to eliminate the necessity of mixing
lubricating oil with the fuel of two-cycle engines by providing a
separate oil system which delivers oil to the engine for
lubrication and eventual delivery with the fuel to the combustion
chamber so that the residue will be burned. With such an
arrangement it is, of course, necessary to provide an adequate
supply of oil so as to insure that the engine can be operated for a
fairly substantial period of time without necessitating
.[.repllenishment.]. .Iadd.replenishment .Iaddend.of the oil
supply. The oil supply should, furthermore, be located in such a
position so that it can be conveniently replenished.
Because of the compact construction of outboard motors, it has been
difficult if not impossible to provide an adequate lubricant
reservoir within the confines of the engine assembly itself.
Although it has been proposed to provide a separate oil tank, this
gives rise to the difficulty of insuring that oil flows from the
tank to the engine under all times when the engine is running. This
necessitates the provision of a separate pump and an arrangement to
insure that the inlet to the pump will be immersed in lubricating
oil during abrupt maneuvering of the associated boat.
It is, therefore, a principal object of this invention to provide
an improved lubricating system for an outboard engine.
It is a further object of this invention to provide an outboard
motor lubricating system embodying a separate oil reservoir.
It is yet a further object of this invention to provide a
lubricating system for an outboard engine wherein a separate oil
reservoir of sufficient capacity may be concealed within the
cowling of the engine and yet conveniently filled.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view of the power head of an outboard
engine constructed in accordance with this invention wherein the
cowling is shown in phantom and portions of the engine have been
broken away.
FIG. 2 is a side elevational view, in part similar to FIG. 1,
showing the cowling in solid lines with portions broken away to
indicate other components of the engine.
FIG. 3 is a top plan view of the engine with still further portions
broken away.
FIG. 4 is a further top plan view of the engine with a portion of
the engine shown in section, this sectional portion being taken
along the line 4--4 of FIG. 2.
FIG. 5 is a cross-sectional view taken along the line 5--5 of FIG.
2.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In the drawings an outboard motor constructed in accordance with
this invention is identified generally by the reference numeral 11.
Inasmuch as the invention relates to the lubricating system for the
motor 11, only the power head has been illustrated and will be
described in detail.
The engine includes a cylinder block 12 having a pair of
horizontally extending vertically disposed .[.cyliner.].
.Iadd.cylinder .Iaddend.bores 13 and 14. Pistons 15 and 16 are
slideably supported within the .[.cyliner.]. .Iadd.cylinder
.Iaddend.bores 13 and 14, respectively. The pistons 15 and 16 are
connected by means of respective connecting rods 17 and 18 to the
throws 19 and 21 of a crankshaft, indicated generally by the
reference numeral 22. The crankshaft 22 is supported for rotation
about a vertically extending axis in a manner to be described by
means of a crankcase 23 which is affixed to the cylinder block 12
in a known manner.
A cylinder head 24 is affixed to a cylinder block 12 and has
chambers 25 and 26 that cooperate with the .[.cyliner.].
.Iadd.cylinder .Iaddend.bores 13 and 14 and pistons 15 and 16 to
form the combustion chambers for the engine. Spark plugs 27 and 28
are carried by the .[.cyliner.]. .Iadd.cylinder .Iaddend.head 24
and cooperate with the chambers 26 and 27 for firing the charge in
these chambers, as is well known.
The ignition system for the spark plugs 27 and 28 includes a
flywheel magneto 29 that is affixed to the upper end of the
crankshaft 22. A starter gear 31 is affixed to the flywheel magneto
29 and is adapted to be operated by an electric starter mechanism,
.[.indicted.]. .Iadd.indicated .Iaddend.generally at 30 (FIGS. 3
and 4) for starting of the engine.
The crankshaft 22 has 3 main .[.bearing.]. .Iadd.bearings
.Iaddend.consisting of an upper bearing portion 32, a center
bearing portion 33, and a lower main bearing portion 34. The upper
and middle main bearing portions 32 and 33 are supported by
respective needle bearing assemblies 35 and 36, respectively. The
lower crankshaft main bearing portion 34 is .[.suppoted.].
.Iadd.supported .Iaddend.by a roller bearing assembly 37. Adjacent
this roller bearing assembly 37, the crankshaft 22 is connected to
a driveshaft 38 that extends downwardly through the driveshaft
housing to the propeller drive (not shown).
The engine 11 is of the two-cycle crankcase compression type. For
that purpose the crankcase 23 is divided into an upper crankcase
chamber 39 which is associated with the cylinder bore 13, in a
manner to be described, and a lower crankcase chamber portion 41,
which is associated with the cylinder bore 14. An oil seal 42
serves the purpose of protecting the upper bearing 35 and also
sealing the upper portion of the crankcase chamber 39. The
crankcase chamber 39 is sealed from the crankcase chamber 41 by
means of a labyrinth-type seal 43 which cooperates with the
crankshaft 22 immediately below .[.it.]. .Iadd.its .Iaddend.center
main bearing portion 33. The lower crankcase chamber 41 is sealed
by the means of the labyrinth seal 43 and an oil seal 44 which also
serves to protect the bearing 37.
An induction system is provided for delivering a fuel air charge to
the crankcase chambers 39 and 41 for eventual transfer from the
respective crankcase portions to the combustion chambers 25 and 26
through respective transfer passages 45 and 46. The induction
system includes an air inlet and silencer 47 which supplies
filtered air to an upper carburetor 48 and a lower carburetor. The
carburetors 48 and 49 discharge into the respective crankcase
chambers 39 and 41 through reed valves 51 and 52 in a known manner.
The portion of the engine thus far described is conventional and
for that reason further details of the components and their
operation has not been described.
It should be readily apparent to those skilled in the art that an
intake charge is delivered from the carburetors 48 and 49 to the
respective crankcase chambers 39 and 41 for transfer to the
combustion chambers through the transfer passages 45 and 46 during
the operation of the engine. Because the pistons 15 and 16 are 180
degrees out of phase with each other due to the offset of the
crankshaft throws 19 and 21, the pressurization in the chambers 39
and 41 will also be out of phase with each other. The labyrinth
seal 43 prevents any significant communication between the
respective crankcase chambers 39 and 41, as has been described.
The lubricating system for the engine 11 includes an oil pump,
indicated generally by the reference numeral 53 (FIGS. 3 and 4).
The oil pump 53 is driven by means of an oil pump drive gear 54
which is formed integrally with the crankshaft 22 immediately
adjacent the lowermost side of the labyrinth seal 43. The
crankshaft oil pump drive gear 54 is .[.o.]. .Iadd.of .Iaddend.the
helical or worm-type and drives a cooperating oil pump gear 55 that
is affixed to an oil pump drive shaft 56 in any known manner.
The oil pump 53 is of the reciprocating plunger type and includes a
plunger 57 that is slideably supported in a bore 58 formed at the
outer end of the oil pump driveshaft 56. An oil inlet chamber 59
and oil outlet chamber 61 are in respective communication with the
bore 58 so as to move oil from a sump to be described to the engine
as the plunger 57 reciprocates.
A cam 62 has a helical face and is affixed for rotation with the
driveshaft 56. The cam 62 engages a pin 63 that is affixed to the
plunger 57 for reciprocating the plunger 57 in opposition to the
action of a return spring 64. As is well known with this type of
pump, rotation of the driveshaft 56 will cause the plunger 57 to
.[.reciprocates.]. .Iadd.reciprocate .Iaddend.due to the action of
the cam 62 and pin 63.
The amount of discharge of the pump 53 is controlled by adjusting
the stroke of the plunger 57. For this purpose, a pulley 65 is
affixed to a sleeve 66. The sleeve 66 is formed with a helical
groove 67 which receives a pin 68 that is, in turn, staked to a
housing 69 formed at the lower end of the pump assembly 53. A disk
71 is affixed to the lower end of the plunger 57 and contacts the
out end of the sleeve 66 so as to limit the degree of return
movement of the plunger 57 toward the cam 62. Rotation of the
pulley 65 causes the sleeve 66 to move axially due to the
cooperation of the pin 68 and slot 67.
The lubricating system is designed in such a way that oil is fed
under pressure from the pump 53 to the upper needle bearing
assembly 35 and to the oil pump drive gears 54 and 55 under
pressure. Lubrication of the remaining components including the
needle bearing 36, roller bearing 37 and rod bearings and piston
pins and the like is accomplished by gravity flow and splash. In
this arrangement it is possible to maintain an extremely compact
arrangement and nevertheless employ a .[.postive.]. .Iadd.positive
.Iaddend.pump for supplying pressurized oil to certain components
of the engine.
To lubricate the upper needle bearing 35, the discharge port 61 of
the oil pump 53 communicates with an oil passage, indicated in part
schematically by the dot-dash line 72 which terminates in an oil
delivery passage 73 formed in the crankcase 23 which terminates at
the bearing 35. Oil which .[.flown.]. .Iadd.flows .Iaddend.past the
bearing 35 will be discharged to the cheeks of .[.thee crankshft.].
.Iadd.the crankshaft .Iaddend.throw 19 so as to lubricate the rod
bearing at the base of the connecting rod 17 and also the journal
at the piston pin between the rod 17 and the piston 15. The oil
will then flow down the crankshaft to the center main bearing
portion 33 of the crankshaft so as to lubricate the center main
bearing 36. The lubricating oil will then be discharged through a
discharge port 74 in the cylinder block 12 adjacent the transfer or
scavenge passage inlet 45. This oil is then mixed with the charge
being transferred to the combustion chamber 25 so as to lubricate
the upper portions of the engine. The excess oil will be burned
during the combustion process and exhausted.
A further oil discharge passage 75 may be provided that extends
from the lower end of the bearing 36 directly into the transfer
passage 45. The passage 75 is positioned just upstream of the the
labyrinth seal 43.
The oil pump 53 has a second discharge conduit, indicated in part
schematically at 76, which extends from the pressure discharge port
61 for lubricating the pump drive gears 54 and 55 and the mechanism
associated with the lower cylinder bore 14. The conduit 76
terminates in a pressure port 77 that communicates directly with
the pump drive gear 55 so as to lubricate this gear and the driving
gear 54. Oil which has lubricated the pump driving gears 54 and 55
will flow down the cheeks of the crankshaft throw 21 so as to
lubricate the upper and lower bearings of the connecting rod 18.
This oil will be discharged downwardly from the lowermost cheek of
the throw 21 for delivery to the lower crankshaft bearing 37. The
excess oil will be transferred from the bearing 37 to the transfer
or scavenge port 46 via a discharge port 78 that is formed in the
cylinder block 12 at the lower end of the bearing 37 and in
communication directly with the transfer or scavenge port 46. This
oil will be mixed with the intake charge and delivered to the upper
portion of the cylinder bore 14 for lubricating the uppermost
components associated with this cylinder. As with the cylinder bore
13, the excess oil will be burned and discharged through the
exhaust port.
An oil tank or sump, indicated generally by the reference numeral
79 is provided for supplying a .[.souce.]. .Iadd.source .Iaddend.of
oil to the pump 53. As will become apparent, the oil tank 79 is
constructed in such a way that it may be conveniently concealed
within the cowling of the engine 11 and yet may be conveniently
refilled without necessitating removal of the cowling. The oil tank
79 is provided with a pair of depending lugs 81 and 82 which are
apertured so that the tank 79 may be supported by the air intake
and silencer 47 and crankcase 23 in a suitable manner, including
the use of bolts 83 and 84. The oil tank 79 is positioned so that
its lower surface is above the uppermost surface of the bearing 35
to insure a ready supply of oil to the pump 53 regardless of abrupt
maneuvering of the associated boat. The oil tank 79 has a depressed
well portion 85 at the end adjacent to the crankcase 23 and a
conduit 86 extends from this well portion to the pump inlet cavity
59. In this way a ready and continuous supply of oil can be
supplied from the tank 79 to the oil pump 53.
The oil tank 79 is provided with a fill opening which is closed by
a cap 86. In addition, an oil level .[.guage.].
.Iadd.gauge.Iaddend., indicated generally by the reference numeral
87, is provided in the upper wall of the tank 79. The power head of
the engine 11 including the oil tank 79 is concealed within a
protective cowling, indicated generally by the reference numeral
88. The cowling 88 .[.including.]. .Iadd.includes .Iaddend.an upper
cover 89 and a lower tray 91. The upper cover 89 is
.[.detachable.]. .Iadd.detachably .Iaddend.affixed to the tray 91
by means of a pair of releasable latches 92 and 93. The latches 92
and 93 may be of any known type and include a rotatable keeper 94
that is operated by the latch and which cooperates with a fixed
keeper 95 affixed in any suitable manner to the lower tray 91.
In order to permit ready access to the oil tank 79 so as to fill it
by removal of the cap 86 and to check the oil level by viewing the
.[.guage.]. .Iadd.gauge .Iaddend.87 without necessitating removal
of the cowling, an oil supply cover, indicated generally by the
reference numeral 96, is provided. The oil supply cover 96 spans an
opening that is formed in the upper cover 89 in proximity to the
oil tank 79 and specifically to the cap 86 and gauge 87. This
opening is defined by a flange of the cover 89 that receives a
gasket 97 so as to sealingly engage the cover 96 when it is
closed.
Affixed to the cover 96 is one or more "U" shaped arms 98 that is
connected by means of a pivot pin 99 to a bracket 101 that is
affixed to the upper cover 89 contiguous to the opening. The oil
supply cover 96 is pivotal between a closed position as shown in
FIG. 2 and an open position as shown in the broken line view of
this figure. A torsional .[.spriing.]. .Iadd.spring .Iaddend.102
operates between the arm 98 and a lug 103 formed on the bracket 101
so as to bias the cover 96 to its opened position.
The oil supply cover 96 is retained in its closed position by means
of a latch mechanism, indicated generally by the reference numeral
104. The latch mechanism consists of a fixed keeper 105 that is
affixed to the cover 96 adjacent its rear end. A locking member 106
has a cylindrical portion 107 that is slideably supported in a
bushing 108 that is affixed to a rear wall 109 of the upper cover
89. An upstanding hook shaped member 111 is integrally formed with
the latch 106 and is adapted to co-act with the keeper 105 to latch
the cover 96 in its closed position. A strap-type spring 112 is
affixed to the bushing member 108 and engages the rear end of the
latch 106 so as to normally bias it to its latched position as
shown in FIG. 2. In order to open the oil supply cover 96 so as to
replenish the oil supply or view the oil level .[.guage.].
.Iadd.gauge .Iaddend.87, the latch 106 is pressed inwardly so as to
clear the keeper 105 and permit the cover 96 to pivot to its opened
position under the action of the spring 102. Once the latch 106 is
released, the spring 112 will return the latch 106 to its normally
latched position. Closure of the oil supply cover 96 will cause the
spring 112 to yield and effect relatching between the keeper 105
and the latch element portion 111.
The oil tank 79 has been described as being supported by the air
silencer 47 and crankcase 23. It is to be understood that it may be
supported in any other manner within the cowling 89 so long as it
is positioned adjacent the upper end to permit convenient and rapid
access to the tank.
From the foregoing description it should be readily apparent that
an extremely compact arrangement has been provided wherein the oil
reservoir may be conveniently concealed within the cowling of the
engine and yet is readily accessible. Also the location of the oil
pump and the arrangement of the lubricating system permits the
maintenance of a short crankshaft without sacrificing engine
lubrication. Although the invention has been described in
conjunction with a two-cylinder engine, it should be readily
apparent that it can be used in conjunction with engines having any
multiple number of cylinders or with single cylinder engines
insofar as the oil supply is provided. Various other changes and
modifications may be made without departing from the spirit and
scope of the invention as defined by the appended claims.
* * * * *