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Патент USA US2107998

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Feb. 8,
F'led 0617. 7,_ 1935
furl A. ?M/Ison
Patented Feb. 8, 1938
Earl A. Rullison, Toledo, Ohio, assignor to The
Tillotson Manufacturing Company, Toledo,
Ohio, a corporation of Ohio
Application October 7, 19-35, Serial No. 43,831
2 Claims. (Cl. 251—119)
This invention relates to valves for carburetion
Figure '7 is a view of modi?ed form of valve
devices and more particularly to air valve car
disc and supporting member of my invention.
buretion devices.
I have shown the arrangement of my inven
The invention has for an object the provision tion as embodied in a carburetor of the so-called
5 of an air valve wherein the valve is of ?at plate
“self-lift” type, but it is to be understood that
like construction cooperating with a valve seat the arrangement may be utilized in any type of
wherein the air valve will admit air to the car
carburetion mechanism.
buretor yet maintaining adequate suction at the
Referring to the drawing in detail, it desig
fuel ori?ce so‘ that a proportionately constant
nates the body of the carburetor which is gen
10 mixture ratio will be maintained throughout a
erally longitudinally cylindrical in con?guration, 10
considerable range of engine speeds.
and is hollow to provide a mixing passage H.
The invention has for further object the pro
The carburetor body is formed with a depending
vision of a reed or air valve of' simple construc
tion, the valve being of a construction which
15 at all times will form a complete and effective
closure without injurious “pounding” of the seat,
and which is formed and arranged to admit a
proportionately increasing volume of air main~
taining the fuel ratio substantially constant
.- throughout a substantial range of engine speeds.
A further object of the invention is the pro
vision of a ?exible air control valve for a car
buretor which may be manufactured in large
quantities with assurance of a uniformity of
5 product and in which no predistortion of the
valve is necessary to insure successful operation
and thus enhancing interchangeability of the
Further objects and advantages are within
the scope of this invention such as relate to
the arrangement, operation and function of the
related elements of the structure, to various de
tails of construction and to combinations of
parts, elements per se, and to economies of man
ufacture and numerous other features as‘ will
be apparent from a consideration of the speci
?cation and drawing of a form of the invention,
which may be preferred, in which:
Figure 1 is a side view of the carburetorifor
housing my invention showing its connection
to a fuel supply;
Figure 2 is a top plan view of the carburetor
illustrated in Figure l;
Figure 3 is a vertical longitudinal sectional
view of the carburetor taken substantially on
the line 3-3 of Figure 2;
Figure 4 is an end view of the carburetor
showing the air valve mechanism;
Figure 5 is an isometric view illustrating the
arrangement of air valve and supporting mem
Figure 6 is an isometric view of the valve sup
porting member particularly illustrating the spi
ral valve seat;
. 1
boss portion l2 arranged for connection to a
fuel supply tank or reservoir Ill. 7 This connec
tion, as illustrated, includes a threaded coupling 1:3
55, conduit it, the latter having a ball check
valve H for a purpose to be hereinafter de
scribed, the conduit projecting substantially to
the bottom of the fuel supply tank M. One end
of the carburetor body it is formed with a cy
lindrical portion 20 which extends into the ex
tremity of an intake manifold 25, the latter
communicating with the cylinders of an internal
combustion engine (not shown). The other end
of the carburetor body is formed with an en—
larged cylindrical portion 23 arranged to ac
commodate a conduit or air horn 215 which may
be formed as a part of an air cleaner or the
like (not shown).
The interior of the depending boss portion 3
,2. is threaded as at 26 to receive a ?tting 2‘!
which is provided with a comparatively small
opening or passage 28 to permit the flow of
liquid fuel therethrough. The ?tting is also pro
vided with a kerf or slot 29 adapted to receive " Lil
a screw driver or other suitable tool for posi
tioning the ?tting 21 in the threaded bore in
boss l2. The upper portion of the bore in the
boss l2 accommodates a fuel nozzle structure 36
having a shoulder Bl which rests against a flange ; ’
rormed at the end of the bore in the boss 12.
The ?tting 27 when threaded to the position
shown in Figure 3 contacts with a lower por
tion of nozzle 3!! to hold the latter in ?xed posi~
tion in the carburetor body.
The nozzle structure is formed beneath the
flange 32 with a reduced portion in such a man
ner as to provide an annular space 33 which
communicates with a chamber in the carburetor
proper adjacent the base of the venturi 45 by
means-of a passage way 34.
The wall of the
chamber 33 formed by a portion of the nozzle
structure is provided withv small horizontally
extending openings 31 so that air may be ad
mitted under certain conditions to the fuel be
fore its extrusion from the nozzle by means of
the passage way 34 and openings 31, thus pro
viding a suitable air bleed, the purpose of which
will be hereinafter explained.
The carburetor body I 8 is provided with a
boss 35 having a threaded bore 36 in alignment
with the axis of the nozzle 30, the bore 36 re
ceiving a threaded member 38 associated with
10 a needle or metering pin 39 having a tapered
extremity 40 adapted to be received into bore
28 of ?tting 21. The member 38 is provided
at its upper extremity with a knurled knob 42
and interposed between the knob and boss 35
15 is a spring 44 serving to exert su?icient friction
between the threads of member 38 and those in
the boss 35 to hold the needle or metering pin
33 in adjusted position. By rotating the knurled
knob 42, the needle 39 may be adjusted relative
20 to ?tting 21 to regulate the amount of fuel
passing through the ori?ce or passage 28 in the
?tting, consequently regulating the amount of
fuel passing through the nozzle 30. It is to be
noted that the inner bore of the nozzle 38 is
25 larger than the diameter of the needle 39 so as to
provide a space 4| for the passage of fuel mix
Positioned interiorly of the carburetor body in
the mixing passage is a Venturi tube 45 which is
arranged so that the nozzle 30 projects through
an opening in one wall of the Venturi tube, the
latter preferably having its maximum point of
restriction near the fuel exit of the nozzle 30
so that the maximum. velocity of air passing
through the mixing passage will occur approxi
mately at the point of discharge of fuel from the
nozzle 30.
Positioned between the Venturi tube and the
exit of the mixing passage is a throttle valve 50
4.0: in the form of a circular disk which is carried
upon a shaft 5! secured thereto by means of a
screw 52 or other suitable means, the shaft being
journalled in bosses 53 and 54 formed on the
carburetor body. An arm 49 is secured to the
shaft 5i for manipulation thereof to regulate or
control the amount of fuel and air mixture sup
plied to the engine. The end of the shaft 5|
adjacent boss 54 is provided with a tenon 55 of
non-circular con?guration which carries an arm
56, the latter having perforations 51 adapted to
selectively receive the extremity of a coil spring
58. The carburetor body is provided with a boss
60 which forms a support for a plate 6| secured
thereto by means of screws 62 and 63, plate 6|
55 having a series of openings or perforations 64,
one of which is adapted to receive the other ex
tremity of the coil spring 58. The arm 49 in
certain installations is connected by means in
the form of a link 48 to a governor mechanism or
60 other automatic speed controlling means which
may be associated with an engine. Thus, in the
present embodiment of the invention, the spring
58 therefore tends to urge the throttle to open
position, its maximum opening movement being
65 limited by means of screw 41, and the governor
under the influence of an increase in speed of the
engine tends to close the throttle valve causing a
corresponding decrease in the quantity of fuel
mixture, thereby reducing the engine speed. The
70 tension of spring 58 may be varied by shifting the
connections of the extremities of the spring to
another of said perforations or different lengths
and sizes of springs may be used in various in
stallations to obtain proper governor controlled
compensation. In this manner, any desired ten
sion may be had urging the throttle valve toward
open position.
A disk valve 66 secured upon ashaft 61 forms
a suitable “choke” or manually operated means
to control the air supply admitted to the carbu
retor. This control in the embodiment illustrated
consists of a ?exible sheath 68 which encloses a
wire or cable 69 connected to the end of an arm
18 carried by shaft 61, the wire being conveyed 10
by means of the sheath to a convenient operating
location (not shown). The sheath or guide 68
for the ?exible wire control is secured by means
of a clip ‘H held in place by means of screw 62.
The invention comprises an air valve for con
trolling the supply of air to the carburetor in
proportion to the speed of the engine with which
it is connected. This arrangement in the embodi
ment illustrated comprises a valve support in
the form of a disk 15 having air passages or open
ings ‘I6 and 11, these passages being normally
closed by means of a flexible annular disk or reed
valve 19, the same being particularly shown in
Figures 3 and 5. The valve 19 is preferably fab
ricated of a ?at sheet of material. A supporting
disk 15 is formed with a valve seat 80 which is
preferably of a spiral con?guration reaching its
highest point adjacent the unattached extremity
of the valve 19 as illustrated in Figures 5 and 6,
the same being ?xedly retained in position upon
disk 15 by means of screws 82. I have found in
practice that a rise of between ten-thousandths
to twenty-thousandths of an inch from the free
end of the valve with respect to the secured end
functions satisfactorily when used with ordinary
engines. The valve disk is fabricated of compara
tively thin steel or similar material having a ?exi
bility that will be acted upon by the suction or
decreased pressure of the air in the carburetor
whereby the valve is opened by such differential 40
in air pressure during engine operation. Thus, in
this form of my invention, a predistortion of the
reed valve is not essential as the stress is placed
upon the valve by the spiral rising valve seat 80,
and the valve reed 19 will ?t tightly against the 45
seat 80. The supporting disk 15 may be held in
place in the end of the carburetor by suitable
means as, for example, a snap ring 85. The disk
15 is preferably provided with a small opening 86
for the purpose of relieving pressure which may be 50
set up by reason of a back?ring condition of the
engine through the carburetor.
This opening
serves the purpose of partially relieving back pres
sure set up in the carburetor by reason of the
back ?ring of the engine and tends to prevent
such back pressure driving or forcing the fuel
in the supply pipe I6 downwardly into the fuel
Figure 7 illustrates a modi?ed form of the
invention wherein the valve support or seat 90
has a uniplanar valve seat surface having an
opening 80' for the admission of air which passes
the valve disk 9|, the parts being shown in dis
assembled relationship. The valve disk BI is
similar in construction to valve disk 19 herein
above described except that the disk is prefer
ably preformed in a spiral con?guration as il
lustrated so as to impart a stress in the movable
portion of the valve disk. In this manner, the 70
disk will be held against the valve seat or sup
port by the inherent stress or tension in the disk.
The one extremity of the valve disk is held in
position upon the valve seat or support by means
of screws (not shown).
The operation of the air valve of my invention
is as follows:
When an internal combustion engine with
which my invention may be utilized is started,
the reciprocation of the piston or pistons in the
engine sets up suction which will elevate fuel
from the fuel supply reservoir past the check
valve blank through the nozzle 39 into the mixing
passage in the carburetor body. During this
10 starting operation, the choke or manually op
erated valve 66 is in closed or partially closed
position so that the engine suction is highly effec
tive to elevate the fuel. When the engine has
started, the choke 66 is opened with a consequent
decrease in pressure behind the valve ‘19 below
atmospheric pressure and due to this lower pres
sure, the reed valve 19 moves inwardly and is
distorted to admit air through the air entrance
211 into the mixing passage in which passage due
to the velocity of the air column moving through
the venturi 45 of the mixing passage fuel from
the nozzle 30 is mixed therewith, which mixture
passes into the internal combustion engine. As
the speed of the engine increases, the velocity
\ and volume of the air passing through the mix
ing chamber of the carburetor will be increased
as there is additional vacuum or decreased pres
sure created within the mixing passage, this
differential in pressure acting upon the air valve
or reed l9 and causing the latter to be opened
a proportionately greater distance to admit addi
tional air supply.
The velocity of such incoming
air as the engine speed increases is also increased
and a proportionately increased amount of fuel
35 will be taken into the mixture through the nozzle
30 whereby there is maintained a substantially
constant proportion of the amount of fuel to air
passing through the carburetor which is main
tained throughout a substantial range of speed
of the internal combustion engine. I have also
found that my invention when utilized with an
internal combustion engine of a single cylinder
or twin cylinder type or with an engine wherein
there exists a substantially intermittent suction
45 due to piston movement upon the carburetor that
a mixture ratio is maintained giving the engine
a high degree of operating e?iciency. I have
found that at comparatively high speeds the pro
portion of fuel taken into the air stream is slightly
50 enriched, and to decrease this tendency toward
enrichment, the nozzle is air bled by means
of the air bleed channel 34 leading from a point
adjacent the forward end of the Venturi tube into
the side wall of nozzle 36 ahead of its discharg
ing point into the mixing passage. By this 5
means, air is admitted to the fuel prior to its
extrusion from the jet which provides more or
less of an air and fuel emulsion being extruded
from the jet at comparatively high engine speeds,
and due to such prior admission of air into the
fuel column, I have found that the tendency of
the mixture to become over-enriched at such
high engine speeds is substantially eliminated.
Thus, I have provided an arrangement whereby
a desirable fuel mixture is supplied to an internal 15
combustion engine by the use of an arrangement
having only one moving part, viz., the reed air
valve. in event of back?re of the engine, the ball
check ll prevents the fuel from being driven
downwardly into the fuel reservoir M.
It is apparent that, within the scope of the in
vention, modi?cations and different arrange
ments may be made other than is herein disclosed,
and the present disclosure is illustrative merely,
the invention comprehending
all variations
What I claim is:
1. An air valve for carburetors including an
element having a port therein; a valve seat sur
face formed on said element adjacent said port; 30
a valve member of split annular con?guration
having an end portion secured to said seat ele
ment and being otherwise free to form a ?exible
Valve portion; said valve seat surface being heli
cally arranged whereby said portion of said valve
member may be ?exed from the element for the 35
passage of air through said port.
2. An air valve for carburetors including a disc
like support member having a port therein; valve
means comprising a ?exible annularly shaped split
member; means to secure one end of said ?exible 40
member to said support, the other end of said
?exible member being free to ?ex; a valve seat
formed on said support adjacent the port therein
and helically arranged with respect to the normal
plane of said support; said valve means and valve 45
seat cooperating to form a variable opening for
the passage of air through said port.
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