Gas and liquid contact apparatus – Fluid distribution – Valved
Reexamination Certificate
2002-07-24
2004-05-25
Chiesa, Richard L. (Department: 1724)
Gas and liquid contact apparatus
Fluid distribution
Valved
C137S423000, C137S434000
Reexamination Certificate
active
06739584
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a carburetor which controls a concentration and an amount of an air-fuel mixture supplied to an engine, and more particularly to a float forming and maintaining a fixed fuel liquid surface within a float chamber of the carburetor in association with a valve seat and a float valve controlling to open and close the valve seat.
2. Description of Conventional Art
A description will be given of a conventional float apparatus of a carburetor with reference to
FIGS. 4 and 5
.
FIG. 4
is a vertical cross sectional view of a main portion of a carburetor, and
FIG. 5
is a horizontal cross sectional view in a line A—A in FIG.
4
. Reference numeral
1
denotes a carburetor main body within which an intake passage
2
extends through in a side direction. A float chamber
4
is formed by a lower recess portion
1
A of the carburetor main body
1
facing downward, and a cup-shaped float chamber main body
3
arranged so as to face thereto.
Reference numeral
5
denotes a valve seat attached to a valve seat boss
1
C of the carburetor main body
1
and arranged so as to face to the inside of the float chamber
4
. A valve seat hole
5
A formed in the valve seat
5
is opened and closed by a float valve
6
movably arranged within the valve seat
5
.
A fuel inflow passage
7
connected to a fuel source (not shown) is open to an upper portion of the valve seat
5
, and a lower end of the float valve protrudes toward an inner portion of the float chamber
4
.
Reference numeral
9
denotes a float corresponding to a fixed liquid surface control apparatus for forming a fixed liquid surface X—X within the float chamber
4
in association with the valve seat
5
and the float valve
6
. The float
9
is constituted by the following elements.
Reference symbol
9
A denotes a cylindrical bearing portion in which a support hole
9
B is pierced so as to extend through in an axial direction, and reference symbol
9
C denotes a first float arranged further in one outer side G
1
from one end
9
D of the bearing portion
9
A and apart from the bearing portion
9
A in a direction of one side B.
In the present embodiment, one side B means a right side in the drawing.
Further, a portion near one end
9
D of the bearing portion
9
A and another side surface
9
F of the first float
9
C are connected by a first connecting arm portion
9
G.
Reference symbol
9
H denotes a second float arranged further in another outer side G
2
from another end
9
J of the bearing portion
9
A and apart from the bearing portion
9
A in a direction of one side B. A portion near another end
9
J of the bearing portion
9
A and another side surface
9
K of the second float
9
H are connected by a second connecting arm portion
9
L.
In accordance with the structure mentioned above, the first float
9
C and the second float
9
H are arranged in the respective outer sides G
1
and G
2
of one end
9
D and another end
9
J of the bearing portion
9
A and apart from the bearing portion
9
A in the direction of one side B, and an inner side surface
9
M of the first float
9
C and an inner side surface
9
N of the second float
9
H are arranged with a gap S.
Further, reference symbol
9
P denotes a flat tongue portion extending from a center portion of the bearing portion
9
A toward one side B in a horizontal direction.
Further, the bearing portion
9
A of the float is rotatably supported to a pair of shaft portions
1
B stood toward an inner portion of the float chamber
4
from the carburetor main body
1
via an arm pin
10
, and at this time, an upper surface of the tongue portion
9
P is arranged so as to face to the lower end of the float valve
6
.
In this case, reference numeral
11
denotes a throttle valve for opening and closing the intake passage
2
, reference numeral
12
denotes a main fuel boss arranging a main fuel system constituted by a needle jet
13
open to the intake passage
2
and the like, and reference numeral
14
denotes a low speed fuel boss arranging a low speed fuel system toward a bypass hole
15
open within the intake passage
2
in correspondence to the throttle valve
11
. These bosses
12
and
14
are provided in a standing manner toward the inner portion of the float chamber
4
from the carburetor main body
1
.
Further, reference numeral
16
denotes a negative pressure response valve variably controlling an open area of the intake passage
2
on the basis of a negative pressure generated within the intake passage
2
. A jet needle
17
integrally attached to the negative pressure response valve
16
is inserted and arranged within the needle jet
13
.
In this case, a fixed fuel liquid surface X—X is formed within the float chamber
4
due to a cooperative effect of the valve seat, the float valve
6
and the float
9
in the following manner.
In a state that the inner portion of the float chamber
4
is empty, the float
9
rotates in a clockwise direction on the basis of an arm pin
10
, and the tongue portion
9
P also rotates in a clockwise direction, whereby the float valve
6
moves in a downward direction so as to open the valve seat hole
5
A.
In accordance with the structure mentioned above, the fuel existing in the fuel inflow passage
7
flows into the float chamber
4
via the valve seat hole
5
A, gradually stores the fuel within the float chamber
4
and gradually raises the fuel liquid surface. Due to the rise of the fuel liquid surface, the float
9
rotates in a counterclockwise direction on the basis of the arm pin
10
, and as soon as a fixed fuel liquid surface (hereinafter, refer to a fixed liquid surface X—X) is formed within the float chamber, the tongue portion
9
P upward moves the float valve
6
so as to close the valve seal hole
5
A, whereby the fixed liquid surface X—X is formed within the float chamber
4
.
Thereafter, when the fuel liquid surface within the float chamber
4
is lowered with respect to the fixed liquid surface X—X, the float valve
6
opens the valve seat hole
5
A on the basis of a rotation of the float
9
in a clockwise direction so as to supply the fuel toward the inner portion of the float chamber
4
from the fuel inflow passage
7
, and as soon as the fixed liquid surface X—X is formed, the float valve
6
closes the valve seat hole
5
A on the basis of a rotation of the float
9
in a counterclockwise direction, the fuel supply from the valve seat hole
5
A into the float chamber
4
is stopped, and these operations are repeated, whereby the fixed liquid surface X—X is always formed within the float chamber
4
.
In accordance with the conventional float apparatus of the carburetor mentioned above, when the fuel liquid surface X—X within the float chamber
4
changes to a right inclined state, it is hard to properly control the fuel liquid surface. (The right inclined state means a right downward state as shown by a single-dot chain line in FIG.
4
). This is caused by the following reasons.
The first and second float
9
C and
9
H are arranged to one side B apart from the bearing portion
9
A. This arrangement is performed for the purpose of placing a center of buoyancy of the float
9
to one side B as apart as possible from a center in a longitudinal direction of the support hole
9
B of the bearing portion
9
A so as to increase a blocking force with respect to the float valve
6
. When the bearing portion
9
A of the float
9
mentioned above is attached to the shaft portion
1
B of the carburetor main body
1
via the arm pin
10
, a comparatively large space K is formed between another side surfaces
9
F and
9
K of the respective float
9
C and
9
H and another side wall
3
A of the float chamber main body
3
.
This space K is expressed by a cross line in FIG.
5
.
In the carburetor using the float
9
, the fixed liquid surface X—X in the horizontal direction is shown in
FIG. 4
, and in this state, the float valve
6
is pressed to the valve seat hole
5
A of the valve seat
5
by the tongue portion
9
P of the float
9
, and closes and holds t
Akabane Akira
Fujino Yuki
Chiesa Richard L.
Keihin Corporation
Sheets Kendal M.
Zito Joseph J.
ZITO tlp
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