Note: Descriptions are shown in the official language in which they were submitted.
3513Z
BACRGROllND OF THE INVENTION
The present lnvention relates to a carburetor construction and,
more particularly, to a carburetor of the 61ide and metering rod type which
i8 generally like those disclosed in my prior patents, Nos. 3,985,839 and
5 - 4,013,741. The carburetor of the present invention is constructed to maximize
the flow of air in the vicinity of the metering rod and fuel outlet to assure
thorough atomization and distribution of tbe fuel in the airstream before it
reaches the combustion chamber, thereby minimizing the possibility of fuel
droplet6 leaving the airstream and condenslng on the wall of the fuel passage.
Although previously used and disclosed carburetors of the slide
and metering rod type have generally served the purpose, these carburetor~
bave been subject to one or more of the following disadvantages:
' ,J ~
(1) Insufficient atomization and distribution of the fuel in the
airstream;
1; (2) Insufficient flow of air in the vicinity of the fuel outlet
and metering rod;
(3) Insufficient choke arrangement;
~ (4) Poor design of metering rod or needle;
--, 20 (5) Difficulty in mounting and adjustment of metering rod or
needle; and/or
(6) Turbulent and inconsistent fuel flow uhen vehicle is subjected
to rough terrain.
Accordingly, it will be readily seen that a need has arisen for a
new and improved carburetor of the slide and metering rod type uhich is not
6ubject to any of the above-mentioned disadvantages. The carburetor of the
pre6ent invention fllls this need and posses6es certain improvements and
tvantage6 which are not embodied in ehe prior art carburetors of thi~ type.
1~ ~13513Z
SUMMARY OF THE INVENTION
The carburetor of the present invention generally comprises a
body defining 8 throat, a throttle slide member slidably mounted on the body
and disposed in the throat, and a tapered metering rod or needle mounted on
S the slide member and extending downwardly into a fuel supply tube leading into
a fuel reservoir or bowl secured to the body The slide member has front and
~rear,~substantislly fl-t panels dlsposed in substantially parallel relation,
q with the front panel being shorter than the rear panel for the purpose of pro-
viding alr at the outlet of the fuel supply tube even when the slide is in a
closed posltion and for dlreceing air toward the outlet when the slide is in
n open posltion The body ls provided with substantially axial groove
lntersecting ~he fuel outlet at the thro-t for the purpose of directing high
speed air flow toward the metering rod and over the fuel outlet when the
slide is opened The metering rod is provided with a downward}y and inwardly
~is 15 tapered, rear flat face and is mounted for longitudinal adjostment relative ;-
to the slide member
The metering rod m y be provided with a plurallty of holes there-
through for the purpose of providing more direct alr flow at the fuel outlet
and better atomlzation of the fuel Also, the metering rod may be provided
with various tapered configurations for different operating characteristics,
such as a straight portion near its lower end and a more radically tapered
i portlon ne-r lt upper end for the purpose of providing a more rapid flow of
fuel for mid-range operat$on
In a further embodiment of the carburetor of the present invention,
the outer faces o the slide member panels may be recessed for the purpose of
rcducing slid$ng frlction, alding in removal of dirt or other foreign matter
from the rim portions thereof and, in the case of the front panel, aiding in
directing incoming air downwardly toward the metering rod and fuel outlet
For the purpose of preventing turbulence in the fuel reservoir or
bowl and insuring a constant fuel flow even when the vehicle is subjected to
rough terrain, the lower end of the fuel supply tube is provided with an
,
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1135~3Z
enlarged downwardly opening flange or "umbrella" portion disposed near the
lower end of the fuel reservoir. The flange portion serves to trap fuel and
prevent turbulence therein, and is provided with an upwardly and inwardly
. tapered inner surface for the purpose of directing fuel upwardly into the fuel
supply tube to further reduce turbulence.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a perspective view of a carburetor constructed in
accordance with the principles of the present invention;
: Pigure 2 is an enlarged sectional view taken substantially along
10 line 2-2 in Figure l;
Figure 3 is an enlarged sectional view taken substantiaily along
line 3-3 of Figure l;
Figure 4 is a sectional view taken substantially along line 4-4 of
: Figure 2;
Figure 5 is an enlarged perspective view of one embodiment of a
metering rod or needle for the carburetor of the present invention;
Figure 6 is a perspective view of one embodiment of a throat
insert and fuel supply tube for the carburetor of the present invention;
Figure 7 is an enlarged sectional view taken substantially along
20llne 7-7 in Figure 4;
Figure 8 is an enlarged perspective view of a modified form of
the throttle slide member of the carburetor of the present invention;
Figure 9 is a partial side elevational view of the carburetor
of the present invention, showing the modified slide member of Figure 8;
25Figure 10 is a rear elevational view of a modified metering rod
or needle for use in the carburetor of the present invention; aod
Figure 11 is an enlarged sectional view taken substantially along
line 11-11 of Figure 10.
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1~35132
DESCRIPTION OF THE PREFERRED EMBODIMENTS .
Referring to Figures 1 through 4, the carburetor 10 of the present
invention generally comprises a body 12 having an air inlet end 14, an air
outlet end 16 and a centrally located slide supporting portion 18; a cover
~5 20 adapted to fit over the upper portion of the slide supporting portion 18;
and a fuel reservoir or bowl 22 secured to the underside of the body beneath
the slide supporting portion 18. Preferably, the inlet end 14, outlet end 16
and slide supporting portion 18 are formed of unitary construction, and a
; throat 24 extends through the body from one end to the other. The cover 20
and reservoir 22 may be removably secured to the body 12 in any suitable
manner, such as by flexible and resilient spring members 21 and 23, respective-
~ ly. ~
As specifically shown in Figures 3, 4 and 6, the body 12 isprovided with an insert 26 fixedly mounted by a locking screw 27 within the
15 slide supporting portion 18. The insert 26 comprises an upper portion 28
having an aperture 30 therethrough that corresponds in size and shape to the
at~acent portions of the throat 24 in the body 12. The upper end of the upper
nsert portion 28 is open and comprises oblique end faces 32, one of which
as a threaded aperture 34 extending therethrough which is adapted to receive
he locking screw 27. A fuel supply tube 36 is secured to the bottom of the
pper portion 28 and extends through an aperture therein into communication
with the aperture 30. The fuel supply tube 36 extends downwardly into the
fuel reservoir or bowl 22 and is provided at its lower end with an outwardly
and downwardly extending flange or "umbrella" portion 38 disposed near the
ower end of the bowl 22 for a purpose to be more fully described hereinafter.
As shown in Figure 4, the insert 26 is narrower than the adjacent
ortlons of the slite supporting portion 18 so as to define grooves on each
side of the slide supporting portion that are adapted to slidably receive the
side ed8e portions of the front and rear panels 40 and 42 of a throttle slide
ember 44 mounted within the slide supporting portion 18 for substantially
ert~cal slidable movement therein. At lts upper portion, the slide member
11
1135~32
44 ls provided with a pair of downwardly facing oblique surfaces 46 whlch are
adapted to engage the complementary oblique faces 32 on the upper end of the
. insert 26 for the purpose of llmiting the downward movement of the slide
member 44 within the slide supporting portion 18 of the body 12. As
.S specifically shown in Figure 3, the locking screw 27 can be adjusted to
engage one of the oblique surfaces 46 on the slide member 44 for the purpose
of adjusting the lowest positioD of the slide member. In addition to the
locking screw 27, the insert 26 may be retained within the slide supporting
portioD 18 by locking pins 48.
- 10 A fuel metering rod or needle 50 is adjustably secured to and
extends downwardly from the slide member 44, through the fuel supply tube 36
and into the flange portion 38 thereof disposed near the bottom of the
reservoir or bowl 22. The metering rod 50 is provided wlth an enlarged head
portion 52 at its upper end *hich is slidably received within an internal
bore 54 within the slide member 44. The head portion 52 is provided with a
key portion 56 that is receivable within a complementary groove 58 in the
slide member bore 54 for the purpose of maintaining the metering rod 50 in a
desired orientation which will be more fully described hereinafter. A coil .
spring 60 or other biasing means is provided between the bottom of the slide
me~ber bore 54 and the lower surface of the head portion 52 of the metering
rod 50 and serves to urge the head portion 52 upwardly away from the lower
end of the bore 54, as specifically shown in Figure 2.
An adjusting screw 62 is threadably mounted within an upper
threaded portion of the slide member bore 54 and has a lower end in engage-
ment with the upper surface of the enlarged head portion 52 of the metering
rod 50. The ad~usting screw 62 is provided with a lower internal bore 64 and
an upper internal bore 66 which are separated by an intermediate flange
portion 68 having an aperture therethrough extend~ng between the lower bore
64 and the upper bore 66. A control cable 70 for the throttle slide member
44 extends through the upper bore 66 in the ad~usting screw 62 and through
the aperture lD the intermediate flange 68. The control cable 70 is provided
` ~ li35132
~ . .
with an enlarged head portion 72 st its lower end which ls disposed wlthin
the lower bore 64 in the ad~usting screw 62 and is in engage~ent with the
. intermediate flange 68 for the purpose of connecting the cable 70 to the
ad~usting screw 62 and to the throttle slide member 44. A helical spring 74
- surrounis the csble 70 snd extends from the lower end of the upper bore 66
and the adjusting screw 62 to the upper end of the slide supporting portion
~ 18. At its upper end, the helical spring 74 surrouDds the lower end of a tube
3, ~ 76 extendlng downwardly from and thread-bly secured in an aperture in the
cover 20 for tbe slide supporting portion 18. The cable 70 extends through
the tube 76 ant the cap member 20 for connection to any suitable type of manual
i control means disposed on the vehicle in whlch the carburetor is mounted.
The helical spring 74 ~erves to urge the slide member 44 to the closed or
down position shown in Figures 2 and 3 wherein it cuts off air flow through the
throat 24 of the body 12. Upward movement of the cable 70 serves to move the
slide member 44 upwardly against the force of the spring 74 to allow sir
flow through the throat 24 and upward movement of fuel from the reservoir 22
through the fuel supply tube 36 in a manner to be described more fully here-
inafter.
i The vertical position of the ~etering rod or needle 50 relative to
the slide member 44 may be easily adjusted by rotation of the adjusting screw
62 whlch is providet at its upper end with a transverse recess 78 or the like
for receiving the head of 8 screwdriver or similar tool. Rotation of the
ad~u6ting screw 62 serves to move the head portion 52 of the metering rod 50
upwardly or downwardly within the lower portion of the bore 54 in the
throttle ~lide member 44.
In one embodiment of the present invention shown in Figures 2, 3 an
5, the metering rod or needle 50 is provided with a downwardly and inwardly
taperet flat portion 80 extending from the upper portion to the lower end
thereof. The key'portion 56 is so locatet on the enlarged head portion 52
of the metering rod 50 that the flat portion 80 faces the outlet end 16 of the
carburetor boty 12 when the metering rot 50 is mountet within the throttle slid~'
11
: 1135132
~ember 44, as specifically shown in Figure 2. ~t wlll be readlly seen,
therefore, that upper movement of the slide member 44 and corresponding
upward movement of the metering rod 50 within the fuel supply tube 36 will
cause a gradually larger opening at the outlet of the fuel supply tube for
. the supply of fuel from the fuel reservoir or bowl 22 to the carburetor
throat 24, owing to the tapered flat portion 80 on the metering rod. By
varying the taper of the flat portion ôO on the metering rod~50, the variation
in fuel flow for a given upward movement of the slide member 44 and metering
rod 50 may be adjusted.
As shown in Figures 2 and 4, the inner surface of the carburetor
body 12 is tapered inwardly from the inlet end 14 to the slide supporting
portion 18 and is tapered outwardly from the slide supporting portion 18
to the outlet end 16, thereby creating a Venturi effect when air flows
through the carburetor throat from the inlet to the outlet end. This air
flow past the metering rod 50 and outlet end of the fuel supply tube 36
serves to create a vacuum at the outlet of the fuel supply tube, thereby
causing a flow of fuel from the fuel reservoir or bowl 22 upwardly through
the opening in the fuel supply tube defined by the metering rod 50 and into
the carburetor throat 24 where the fuel is mixed with incoming air and moves
toward the outlet end therewith. The fuel flows upwardly from the fuel
reservoir 22 into the fuel ~upply tube 36 because the reservoir 22 is vented
to the atmosphere in a manner to be more fully described hereinafter.
The fuel reservoir bowl 22 is provided with a suitable float
valve assembly 82 or any other sultable means for maintaining a minimum
guantity of fuel in the reservoir. The float valve assembly 82 is connected
to a fuel supply tube 84 in any suitable manner.
The downwardly extending flange portion 38 on the lower end of
the fuel supply tube 36 serves to trap fuel within it and to keep air from
entering the fuel supply tube when the carburetor is subjected to vibration
o~ing to travel of the vehlcle over rough terrain or the like. By trapping
fuel withln it, the flange portlon 38 also serves to reduce turbulence in the
I -
- 8 - I
ll
~35~32
fuel entering the lower end of the fuel supply tube. A smooth supply Pf
fuel to the lower end of the fuel supply tube 36 is further enhanced by the
upwardly ant inwardly tapered inner surfaces 86 of the flange portion 38
which lead to the lower end of the fuel supply tube.
`5 It will be appreciated that upward and downward movement of the
throttle slide member 44, as actuated by the control cable 70, serves to
control the air flow frcm the inlet end to the outlet end of the carburetor
body 12 and also serves to control the flow of fuel from the fuel reservoir or
bowl 22 to the carburetor throat 24 because of corresponding upward or
downward movement of the metering rod 50 secured to the throttle slide member
44. A significant feature of the present invention is to maximize air flow
past the metering rod and upper outlet end of the fuel supply tube 36 to
assure thorough atomization and distribution of the fuel in the airstream
before it reaches the combustion chamber. This is accomplished by providing
the throttle slide member 44 with a lower end that is tapered downwardly from
the front panel 40 to the rear panel 42 thereof, as shown in Figure 2. In
other words, the front panel 40 is shorter than the rear panel 42 so that, ~hen
the throttle slide member is in the closed position shown in Figure 2, the
metering rod 50 and outlet end of the fuel supply tube 36 are exposed to air
from the inlet end 14 of the carburetor body 12. In this manner, when the
throttle slide member 44 is moved upwardly to open the carburetor throat 24,
air is already present at the outlet of the fuel supply tube 36 to effect
i ediate mixing with the fuel drawn upwardly through the fuel supply tube,
thereby insuring thorough atomization of the fuel. In addition, the tapering
of the lower end of the throttle slide member 44 serves to direct or "tunnel"
sir flow downwardly toward the metering rod 50 and outlet of the fuel supply
tube 36 to further enhance air flow and mixing with the fuel at this point.
Air flow across the outlet end of the fuel supply tube 36 and
atomization of the fuel entering the carburetor throat at this point is
further enhanced by the provision of a longitudinally extending groove 88 in
the inner surface of the carburetor body 12 which intersects the metering rod
113513Z
50 and outlet of the fuel supply tube 36 and extends from the inlet side of
the throttle slide member to the outlet side tbereof. As shown in Figure 6,
the groove 88 extends through the upper portion 28 of the insèrt 26 dlsposed
within the slide supporting portion 18 of the carburetor body 12. The groove
88 serves to direct air flow and to concentrate it at the metering rod 50
and outlet of thè fuel supply tube 36, thereby further enhancing atomization
and di~tribution of the fuel in the airstream before it reaches the combustion
chsmber.
In a modificatioo of the present invention, as shown in Figures 8
and 9, the central portions 40a and 42a of the front and rear panels 40 and
42, respectively, of ehe throttle slide member 44 are recessed to reduce slid-
ing friction between these panels and the adjacent inner surfaces of the
slide supporting portion 18 of the carburetor body 12, and also to facilitate
the removal of dirt or other foreign matter from the areas between froDt and
rear panels of the slide member 44 and the surrounding portions of the slide
supporting portion 18.
As specifically shown in Figure 9, the recessed area 40a of the
front panel 40 of the throttle slide member 44 aids in directing air flow
downwardly toward the lower tapered portion of the slide member, the metering
rod 50 and the outlet of the fuel supply tube 38. This is accomplished
because incoming air tends to be locked in the pocket formed by the recessed
area 40a on the front panel 40, in the manner shown by the lead lines and
arrows in Figure 9, thereby directing the following air downwardly toward the
metering rod 50 and the outlet of the fuel supply tube.
Flgures 10 and 11 illustrate another embodiment of the metering
rod 50 wherein a plurallty of vertically spaced, transverse bores 50a extend
rearwardly from the front surface thereof to the rear flat surface 80 thereof.
,The bores 50a serve to further maximize direct air flow over the outlet of
¦Ithe fuel supply tube 3B to further enhance fuel atomization and distribution.
jiBy reducing air displacement around the metering rod 50, the bores 50a create
¦Imore direct air flow for efficient mixing with the fuel at the entry point
l into the carburetor throst.
I
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~ 1135132
The carburetor of the present invention also includes an i~proved
cboke arrangement which allows extra fuel to be atomized and to enter the
carburetor throat when desiret. As shown in Figures 1, 2, 4 and 7, the
carburetor body 12 is provided with a longitudinal bore 90 extending from the
S inlet end 14 thereof to a point rearwardly of the slide support portion 18.
: The longitudinal bore 90 intersects with a transverse bore 92 extending into
the carburetor throat 24 at the outlet portion of the carburetor body 12 and
also intersect6 with a fuel supply bore 94 extending downwardly to the lower
portion of the carburetor body 12. A choke fuel supply tube 96 is secured
at its upper end to the carburetor body 12 in communication with the bore 94
; and extends downwardly into a choke fuel supply bore 98 in the fuel reservoir
or bowl 22. The up~er end of the fuel supply bore 98 is vented to the
atmosphere in any suitable manner (not shown) and an aperture 100 ~see
Figure 2) is provided in a lower portion of the carburetor body 12 for the
purpose of conveying atmospheric pressure from the bore 98 to the upper end .
of tbe reservoir or bowl 22. The fuel supply tube 96 is provided with one
or more vent openings 102 for the purpose of enhancing upward flow of fuel
from the reservoir 22 into the choke fuel supply bore 98 and through the
choke fuel supply tube 96.
At the intersection of the bores 90, 92 and 94, a cylindrical valve
member 104 i6 rotatably mounted within the carburetor body 12. The valve
member 104 ha~ a stem portion 106 extenting outwardly of the carburetor body
12 and ~ecuret in any suitable ~anner to an actuating member 108 of any
~uitable type. The cylindrlcal valve member 104 is provided with a large
open$ng 110 and small opening 112 in the wall thereof which are spaced apart
by n angle of 90 degrces so that when the valve member is rotatet to the
open po~ition shown in Figures 4 and 7, the large opening 110 is in communi-
cation with the air supply bore 90 and the small opening 112 is in communica-
tion with the fuel supply bore 94, thereby supplying an auxiliary air and
fuel mixture to the carburetor throat tbrougb the valve member 104 and
transverse borc 92. The chokc will be inoperative when the choke valve me~ber
104 ls rotatet to a positioD other than that sbown iD Figures 4 and 7 so as tO
cut off com~uoicatioD betweeD the air supply bore 90 and the fuel supply bore
94.
