LEVER BASED GRADE VENT VALVE
TECHNICAL FIELD
[0001] The invention generally relates to a grade vent valve assembly, sometimes
referred to as a roll-over vent valve assembly.
BACKGROUND
[0002] Vehicular fuel systems include a fuel tank having a grade vent valve
assembly. The grade vent vale assembly opens fluid communication between the fuel
tank and other components of the fuel system to allow pressurized fuel vapor to escape
the fuel tank under normal conditions, and closes fluid communication between the fuel
tank and the other components of the fuel system to prevent liquid fuel from flowing
out of the fuel tank when the vehicle is at an extreme angle or in an inverted position,
i.e., in a rolled-over position.
SUMMARY
[0003] A grade vent valve assembly for a fuel tank of a vehicle is provided.
The grade vent valve assembly includes a housing. The housing defines a float
chamber, an inlet open to the float chamber, a liquid sealing chamber in fluid
communication with the float chamber, and an orifice open to the liquid sealing
chamber. A float is disposed within the float chamber. The float is moveable between
a lowered position and a raised position. The grade vent valve assembly further
includes a lever. The lever includes a first end that is coupled to the float. The lever
extends from the first end across the orifice to a second end. The lever pivots about a
fulcrum between an open position and a sealing position. When in the open position,
the lever allows fluid communication between the orifice and the inlet. When in the
sealing position, the lever blocks fluid communication between the orifice and the inlet.
The lever moves between the open position and the sealing position in response to
movement of the float between the lowered position and the raised position. The lever

is disposed in the sealing position when the float is disposed in the raised position, and
is disposed in the open position when the float is disposed in the lowered position.
[0004] A roll-over vent valve assembly for a fuel tank of a vehicle is also
provided. The roll-over vent valve assembly includes a housing. The housing defines
a float chamber, an inlet open to the float chamber, a liquid sealing chamber in fluid
communication with the float chamber, and an orifice open to the liquid sealing
chamber. A float is disposed within the float chamber. The float is moveable between
a lowered position and a raised position. A biasing device is disposed within the float
chamber between the housing and the float. The biasing device is configured for
biasing the float into the raised position. The roll-over vent valve assembly further
includes a lever. The lever includes a first end pivotably coupled to the float. The
lever extends from the first end across the orifice to a second end. The lever pivots
about a fulcrum between an open position and a sealing position. When in the open
position, the lever allows fluid communication between the orifice and the inlet. When
in me sealing position, the lever blocks fluid communication between the orifice and the
inlet. The lever moves between the open position and the sealing position in response
to movement of the float between the lowered position and the raised position. The
lever is disposed in the sealing position when the float is disposed in the raised position,
and is disposed in the open position when the float is disposed in the lowered position.
A sealing member is attached to the lever adjacent the second end of the lever. The
sealing member is moveable with the lever. The sealing member includes a synthetic
rubber material and is configured for sealing against an interior surface of the liquid
sealing chamber to seal the orifice. A locating mechanism interconnects the sealing
member and the housing. The locating mechanism is configured for positioning the
sealing member relative to the orifice. A cover is attached to and in sealing
engagement with the housing. The cover further defines the float chamber and the
liquid sealing chamber.
[0005] Accordingly, the leverage created by rotating the lever about the
fulcrum, which is disposed between the first end of the lever and the second end of the
lever, increases the force applied to break the seal between the sealing member and the

interior surface of the liquid sealing chamber, thereby improving the re-opening
characteristics of the vent valve assembly.
[0006] The above features and advantages and other features and advantages of
the present invention are readily apparent from the following detailed description of the
best modes for carrying out the invention when taken in connection with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Figure 1 is a schematic exploded view of a grade vent valve assembly.
[0008] Figure 2 is a schematic cross sectional view of the grade vent valve
assembly showing a float in a lowered position and a lever in an open position.
[0009] Figure 3 is a schematic cross sectional view of the grade vent valve
assembly showing the float in a raised position and the lever in a sealing position.
[0010] Figure 4 is a schematic cross sectional view of the grade vent valve
assembly showing a pressure relief mechanism.
[0011] Figure 5 is a schematic perspective view of the grade vent valve
assembly.
DETAILED DESCRIPTION
[0012] Those having ordinary skill in the art will recognize that terms such as
"ab ove," "below," "upward," "do wnward," "top," "bottom," etc., are used
descriptively for the figures, and do not represent limitations on the scope of the
invention, as defined by the appended claims.
[0013] Referring to the Figures, wherein like numerals indicate like parts
throughout the several views, a grade vent valve assembly is generally shown at 20.
The grade vent valve assembly 20 may also be referred to as a roll-over vent valve
assembly 20. The grade vent valve assembly 20 is positioned at a top wall 22 of a fuel
tank 24 of a vehicle. The grade vent valve assembly 20 includes a pressure relief
mechanism 26, described in greater detail below, which allows fuel vapors to escape
from the fuel tank 24 during normal operating condition. When the fuel tank 24 is

oriented at an extreme angle or upside down, such as in the event of a vehicular roll-
over, the grade vent valve assembly 20 is configured to block fluid flow from the tank,
thereby preventing fuel leakage from the tank.
[0014] Referring to Figures 1 through 3, the grade vent valve assembly 20
includes a housing 28. The housing 28 may include and be formed from, but is not
limited to an acetal material, or some other similar material. The housing 28 defines a
float chamber 30, and an inlet 32 open to the float chamber 30. The inlet 32 is
disposed within the fuel tank 24 adjacent the top wall 22 of the fuel tank 24 such that
fuel vapors that rise to the top of the fuel tank 24 may flow through me inlet 32 of the
housing 28 and into the float chamber 30. The housing 28 further defines a liquid
sealing chamber 34, and an orifice 36 open to the liquid sealing chamber 34. The
orifice is shown in the Figures having a circular shape. However, it should be
appreciated mat me orifice 36 may include any suitable shape. The liquid sealing
chamber 34 is in fluid communication with the float chamber 30. Accordingly, fuel
vapors passing through the inlet 32 of the housing 28, may pass through the float
chamber 30, around a float 42 and into the liquid sealing chamber 34, and exit the liquid
sealing chamber 34 through the orifice 36. The orifice 36 is in fluid communication with
the pressure relief mechanism 26. Under normal operating conditions, the vapors passing
through the orifice 36 exit the grade vent valve assembly 20 through the pressure relief
mechanism 26 when the fuel vapors reach a pre-determined pressure.
[0015] The grade vent valve assembly 20 includes a cover 38. The cover 38 is
attached to and in sealing engagement with the housing 28. The cover 38 may be
attached to the housing 28 in any suitable manner, including but not limited to attaching
the cover 38 to the housing 28 wiui detents 40 and/or fasteners. The cover 38 may
include and be manufactured from, but is not limited to, HDPE or some other similar
material. The cover 38 cooperates with the housing 28 to further defining the float
chamber 30 and the liquid sealing chamber 34. More specifically, the cover 38 defines
the top surface and/or region of the float chamber 30 and the liquid sealing chamber 34.
[0016] The float 42 is disposed within me float chamber 30. The float 42 may
include and be formed from, but is not limited to an acetal material, or some other

similar material. The float 42 is moveable between a lowered position, shown in
Figure 2, and a raised position, shown in Figure 3. Under normal operating
conditions, the float 42 remains in the lowered position. However, if the vehicle is
disposed at an extreme angle, causing liquid fuel to enter the inlet 32, then the
buoyancy of the float 42 caused by any liquid fluid within the float chamber 30 causes
the float 42 to rise to the raised position.
[0017] A biasing device 44 is disposed within the float chamber 30. The
biasing device 44 is disposed between the housing 28 and the float 42. More
specifically, the biasing device 44 is disposed between a bottom wall 46 of the float
chamber 30 and the float 42. The biasing device 44 is configured to bias the float 42
into the raised position. Accordingly, the biasing device 44 provides a biasing force
acting to move the float 42 from the lowered position into the raised position. While
the biasing force is not great enough to move the float 42 alone, the biasing device 44
cooperates with the buoyancy force generated by any liquid entering the float chamber
30 to move the float 42 into the raised position. Preferably, the biasing device 44
includes a coil spring manufactured from stainless steel. However, the biasing device
44 may include a device other than the coils spring shown, and may be manufactured
from some other material.
[0018] A lever 48 is disposed within the housing 28, and spans across the float
chamber 30 and the liquid sealing chamber 34. The lever 48 includes an elongated
planar substrate, and may include and be manufactured from, but is not limited to an
acetal material, or some other similar material. A pivotable connection 50
interconnects the lever 48 and the housing 28. The pivotable connection 50 may be
formed in any suitable manner capable of connecting the lever 48 to the housing 28 and
cause the lever 48 to rotate about a rotation axis 52. As shown, the lever 48 includes
two perpendicularly extending pins 54 that are rotatably supported by a pair of supports
56 disposed on opposite longitudinal sides of the lever 48. The interaction between the
pins 54 and the supports 56 define the pivotable connection 50. The pivotable
connection 50 may be positioned relative to the lever 48 other than shown and
described herein, i.e., below or level with the lever 48. The pivotable connection 50

defines a fulcrum about which the lever 48 rotates. Accordingly, the fulcrum defines
the rotation axis 52.
[0019] The lever 48 includes a first end 58 that is pivotably coupled to the float
42. The first end 58 of the float 42 moves vertically with the float 42 as the float 42
moves between the lowered position and the raised position. The first end 58 of the
lever 48 may be pivotably coupled to the float 42 in any manner capable of allowing
rotation of the lever 48 about the rotation axis 52, while securing the first end 58 of the
lever 48 relative to the float 42 for vertical movement therewith.
[0020] The lever 48 extends from the first end 58 to a second end 60 disposed
across the orifice 36 from the first end 58. The lever 48 pivots or rotates about the
fulcrum, which is disposed between the first end 58 of the lever 48 and the second end
60 of the lever 48. The lever 48 pivots between an open position, shown in Figure 2,
and a sealing position, shown in Figure 3. When in the open position, the lever 48
allows fluid communication between the orifice 36 and the inlet 32, thereby allowing
vapors to flow from the fuel tank 24 to the pressure relief mechanism 26. When in the
sealing position, the lever 48 blocks fluid communication between the orifice 36 and the
inlet 32. The lever 48 pivots between the open position and the sealing position in
response to the movement of the float 42 between the lowered position and the raised
position. The lever 48 is disposed in the sealing position when the float 42 is disposed
in the raised position, and the lever 48 is disposed in the open position when the float
42 is disposed in the lowered position.
[0021] The first end 58 of the lever 48 is coupled to the float 42 at a first force
application location 62. A center of the orifice 36 is positioned relative to the lever 48
at a second force application location 64. The lever 48 defines a length 66 between the
first force application location 62 and the second force application location 64. The
fulcrum is disposed a first distance 68 from the first force application location 62 and a
second distance 70 from the second force application location 64. The first distance 68
is preferably at least equal to or greater than ten percent (10%) of the length 66 of the
lever 48, and the second distance 70 is preferably also at least equal to or greater than
ten percent (10%) of the length 66 of the lever 48. Preferably, the fulcrum is disposed

at an approximate midsection of the lever 48, with the first distance 68 approximately
equal to the second distance 70.
[0022] A sealing member 72 may be attached to the lever 48 adjacent the second
end 60 of the lever 48. The sealing member 72 may be moveable with the lever 48.
As shown, the sealing member 72 is configured for sealing against an interior surface
74 of the liquid sealing chamber 34 about a periphery of the orifice 36 to seal the
orifice 36. The sealing member 72 is brought into contact with the interior surface 74
when the lever 48 is moved into the sealing position. Accordingly, liquid entering the
float chamber 30, which is shown in Figure 3, moves the float 42 from the lowered
position into the raised position, thereby moving the lever 48 from the open position
into the sealing position. As the liquid drains from the float chamber 30, such as
shown in Figure 2, the float 42 returns back to the lowered position, thereby moving
the lever 48 back to the open position and breaking the seal between the sealing
member 72 and the interior surface 74 of the liquid sealing chamber 34, thereby
allowing vapors to flow to the pressure relief mechanism 26 again.
[0023] As shown, the sealing member 72 includes a ribbon 76 disposed between
the lever 48 and the interior surface 74 of the liquid sealing chamber 34. Referring to
Figure 4, the ribbon 76 includes a width 78 that is greater than a width 80 of the orifice
36. Alternatively, the sealing member 72 may be secured about a periphery of the
orifice 36, with the lever 48 moving into sealing engagement with the sealing member
72 when the lever moves into the closed position. The sealing member 72 may include
and be manufactured from, but is not limited to a pliable material. The pliable material
may include but is not limited to a synthetic rubber material, such as viton.
[0024] Referring to Figures 1 and 5, a locating mechanism 82 interconnects the
sealing member 72 and the housing 28. The locating mechanism 82 is configured to
position the sealing member 72 relative to the orifice 36. As shown, the locating
mechanism 82 includes a pair of posts 84 extending upward from the interior surface 74
of the liquid sealing chamber 34, that extend through a pair of cutouts 86 in the sealing
member 72 to align the sealing member 72. When disposed between the lever 48 and
the interior surface 74 of the liquid sealing chamber 34, with the posts 84 extending

through the cutouts 86 of the sealing member 72, the sealing member 72 is positionally
located relative to the lever 48. The sealing member 72 is further attached to the
second end 60 of the lever 48 so as to move with the second end 60 of the lever 48. It
should be appreciated that the sealing member 72 may be shaped, sized and/or
configured in some other manner than shown and described herein that is capable of
moving with the lever 48 to seal the orifice 36 when the lever 48 is in the sealing
position.
[0025] Referring to Figures 1 and 4, the housing 28 and the cover 38 further
cooperate to define a pressure chamber 88. The pressure chamber 88 is in fluid
communication with the orifice 36 to receive vapor therefrom. The pressure relief
mechanism 26 is disposed within the pressure chamber 88 in fluid communication with
the orifice 36. As noted above, the pressure relief mechanism 26 is configured for
venting pressurized vapors therethrough. As best shown in Figure 4, the pressure relief
mechanism 26 includes a stainless steel ball 90 seated on a concave opening 92 defined
by the housing 28. The concave opening 92 is in fluid communication with the orifice
36. When the pressure of the vapor reaches the pre-defined pressure, the vapor
pressure lifts the ball vertically upward, thereby allowing the vapors to pass around an
outer periphery of the ball and exit the grade vent valve assembly 20. As shown in
Figure 4, when the vapor pressure is below the pre-defined pressure, the weight of the
stainless steel ball 90 positions the stainless seal ball on the concave opening 92 to seal
the concave opening 92 and block fluid and/or vapor flow through the concave opening
92. It should be appreciated that the pressure relief mechanism 26 may be configured
and operate in some other manner not shown or described herein.
[0026] While the best modes for carrying out the invention have been described
in detail, those familiar with the art to which this invention relates will recognize various
alternative designs and embodiments for practicing the invention within the scope of the
appended claims.

We Claim:
1. A grade vent valve assembly 20 for a fuel tank 24 of a vehicle,
the grade vent valve assembly 20 comprising:
a housing 28 defining a float chamber 30, an inlet 32 open to the float
chamber 30, a liquid sealing chamber 34 in fluid communication with the float chamber
30, and an orifice 36 open to the liquid sealing chamber 34;
a float 42 disposed within the float chamber 30 and moveable between a
lowered position and a raised position; and
a lever 48 having a first end 58 coupled to the float 42 and extending
across the orifice 36 to a second end 60, wherein the lever 48 pivots about a fulcrum
between an open position allowing fluid communication between the orifice 36 and the
inlet 32 and a sealing position blocking fluid communication between the orifice 36 and
the inlet 32 in response to movement of the float 42 between the lowered position and
the raised position;
wherein the lever 48 is disposed in the sealing position when the float 42
is disposed in the raised position, and the lever 48 is disposed in the open position when
the float 42 is disposed in the lowered position.
2. A grade vent valve assembly 20 as set forth in claim 1 further
comprising a biasing device 44 disposed within the float chamber 30 between the
housing 28 and the float 42 and configured for biasing the float 42 into the raised
position.
3. A grade vent valve assembly 20 as set forth in claim 1 wherein
the fulcrum is disposed at an approximate midsection of the lever 48.
4. A grade vent valve assembly 20 as set forth in claim 1 wherein
the first end 58 of the lever 48 is coupled to the float 42 at a first force application
location 62 and the orifice 36 is positioned relative to the lever 48 at a second force

application location 64, and wherein the fulcrum is disposed a first distance 68 from the
first force application location 62 and a second distance 70 from the second force
application location 64.
5. A grade vent valve assembly 20 as set forth in claim 4 wherein
the lever 48 defines a length 66 between the first force application location 62 and the
second force application location 64, and wherein the first distance 68 is at least equal
to or greater than ten percent (10%) of the length 66.
6. A grade vent valve assembly 20 as set forth in claim 4 wherein
the lever 48 defines a length 66 between the first force application location 62 and the
second force application location 64, and wherein the second distance 70 is at least
equal to or greater than ten percent (10%) of the length 66.
7. A grade vent valve assembly 20 as set forth in claim 1 further
comprising a sealing member 72 attached to the lever 48 adjacent the second end 60 of
the lever 48 and moveable with the lever 48, wherein the sealing member 72 is
configured for sealing against an interior surface 74 of the liquid sealing chamber 34 to
seal the orifice 36.
8. A grade vent valve assembly 20 as set forth in claim 7 wherein
the sealing member 72 includes a ribbon 76 disposed between the lever 48 and the
interior surface 74 of the liquid sealing chamber 34 and including a width 78 greater
than a width 80 of the orifice 36.
9. A grade vent valve assembly 20 as set forth in claim 7 further
comprising a locating mechanism 82 interconnecting the sealing member 72 and the
housing 28 and configured to position the sealing member 72 relative to the orifice 36.

10. A grade vent valve assembly 20 as set forth in claim 1 further
comprising a pivotable connection 50 interconnecting the lever 48 and the housing 28
and defining the fulcrum.