Note: Descriptions are shown in the official language in which they were submitted.
CA 02350840 2008-10-01
60680-1475 (5459-1 VIC) PATENT
GASKET TAB RETAINER
FIELD OF THE INVENTION
lo [0002] The present invention relates to a gasket tab retainer. More
particularly,
the present invention relates to a multiple layer steel laminate gasket
including at least
two integral tabs formed in a metal layer of the gasket to locate and retain
the gasket
on a mating flange.
BACKGROUND OF THE INVENTION
[0003] Gaskets are often used as seal between mating metal surfaces. One
common application involves the placement of a gasket between a head and an
exhaust manifold of an internal combustion engine. Another application
involves
gasket placement between the exhaust manifold and an exhaust pipe flange.
Gaskets
for either application can be considered high temperature gaskets and more
particularly exhaust manifold gaskets since they provide an exhaust seal which
prevents the byproducts of combustion exiting the engine from escaping into
the
engine compartment of a vehicle.
[00041 Exhaust manifold gaskets are typically installed by placing the gasket
between an exhaust manifold and its mating component and aligning bolt holes
or
apertures formed in the gasket with corresponding holes formed in the manifold
and
mating component. Typically, a threaded fastener passes through the manifold
and
gasket and engages a corresponding threaded aperture formed in the mating
component. Some maneuvering of the manifold and gasket relative to the mating
component may be required to align the holes therein with the corresponding
threaded
aperhtres of the mating component before the fasteners can be inserted.
However,
during the assembly process, the gasket may slip from its desired position or
drop off
-1-
- ~._., r_t..Ii,Tõ 1CT 7Q t an')'7ARTTC
CA 02350840 2001-06-15
60680-1475 (5459-1 VIC) PATENT
the end of the inserted fastener before it can be fixed in place between the
exhaust
manifold and its mating component.
[0005] Attempts have been made to retain a gasket against a mating component
prior to and during assembly by providing separate clips for attaching the
gasket to a
gasket attaching portion of an engine part. Using such clips, a gasket is
placed
adjacent the mating component, and the separate clip is attached to the mating
component such that the gasket is secured in place between the clip and the
mating
component. The separate clips typically include one end for contacting the
gasket
about an outer periphery thereof while a second end is attached to an outer
periphery
1o of a mating component or to an outer periphery of a connecting portion
between
mating components. Use of such separate clips does not eliminate the problems
involved in the assembly process whereby a gasket may slip from its desired
position.
The clip attached to an outer periphery of the mating component may be jostled
or
become otherwise dislodged by contacting adjacent parts. Further, separate
clips may
become dislodged during sub-assembly handling and shipping of mating
components,
allowing the gasket to slip or drop. As a result, the gasket sealing portion
may become
offset or misaligned from the holes to be sealed before assembly, again
requiring
some maneuvering of the manifold and gasket relative to the mating component
during assembly in order to achieve a tight seal. Assembly of a gasket to a
mating
flange using separate clips is also a complex operation, requiring multiple
parts and
means to hold the gasket adjacent the mating flange while the clips are
attached.
Finally, because such clips are designed to interact with an outer periphery
of a
gasket, the gasket itself must cover the full radial extent of a mating
surface.
SUMMARY OF THE INVENTION
[0006] An exhaust manifold gasket for sealing between an exhaust header and a
mating flange is provided that includes integral tabs formed on an outer
periphery of
the gasket to locate and retain the gasket on the mating flange. In accordance
with the
present invention, at least two tabs are integrally formed on an outer
periphery of a
metal layer of a multiple layer steel laminate gasket for attaching the gasket
to a first
mating flange. After the gasket is attached, the first mating flange to which
the gasket
-2-
Express Mail Label No. EL781402788US
CA 02350840 2001-06-15
60680-I475 (5459-1 VIC) PATENT
is attached by the tabs is easily fixed to a second mating flange without
supporting the
gasket between the flanges.
[0007] The gasket of the present invention includes a metal layer having a
length
and a width, wherein the length is greater than the width. The metal layer
constitutes
at least a part of the gasket, and includes at least one hole formed therein
corresponding to an exhaust gas flow hole in the first mating flange. A first
outer
periphery is defined by a radially outer edge of the first mating flange,
while the
gasket length and width defines a second outer periphery. The second outer
periphery
fits entirely within the first outer periphery. At least two tabs are
integrally formed
along the width of the layer, and are bent generally perpendicular relative to
the rest
of the gasket. The two tabs prevent the gasket from rotating relative to the
mating
flange after the gasket has been installed. The first mating flange fitrther
includes at
least two apertures located within the first outer periphery that are sized
and
positioned to receive the tabs.
[0008] In one preferred embodiment, each tab comprises two contoured,
resilient
legs separated to form a vertical slot between the legs. Each tab leg further
includes a
contoured tip located at a distal end of each tab leg. The contoured tip
includes a
sloped portion that slopes laterally outwardly from the distal end of each tab
leg along
an outside edge of each tab leg. The sloped portion terminates in a laterally
outwardly
2o extending protnision that creates an interference fit when inserted into
the aperture.
The vertical slot between the legs allows each leg to deform to adjust for
aperture size
tolerance.
[0009] Because the apertures are formed inside the configuration of the mating
component, i.e. within the first outer periphery, a gasket formed according to
the
present invention uses less material, thereby reducing cost. The resilient tab
legs
deform when inserted into the corresponding apertures, such that insertion of
the legs
into corresponding aperh.ires positively locates the gasket in place against
the mating
flange. Thus, the configuration of the resilient legs produces a tight
interference fit
within the apertures. The gasket is therefore held tightly in place by the tab
legs. The
tab legs are also positioned vertical to the width of the gasket, allowing for
adjustment
of the gasket relative to the mating flange to account for linear tolerances
of the
apertures and for gasket tolerances. Finally, the tabs are integral to a metal
layer that
-3-
Express Mail Label No. EL781402788US
CA 02350840 2001-06-15
60680-1475 (5459-1 VIC) PA TENT
comprises at least a portion of a gasket, so that manufacture is easily
accomplished.
Moreover, no separate clips are needed to positively locate the gasket
adjacent a
mating flange.
[0010] In a second preferred embodiment, each tab comprises a serrated side
edge. The edge is oriented such that the tab may be easily inserted into a
mating
aperture. However, the edge digs into the inner periphery of the mating
aperture upon
attempted removal of the tab.
[0011] In accordance with a third embodiment, a two layer laminate gasket is
disclosed having at least two mounting apertures. The gasket includes at least
two
lo tabs; each tab being integrally formed on an inner periphery of an
aperture. The
geometry and function of the tabs are substantially similar to those disclosed
in the
first two embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The features and inventive aspects of the present invention will become
more apparent upon reading the following detailed description, claims, and
drawings,
of which the following is a brief description:
[0013] FIG. 1 is a top view showing a component such as an engine manifold
with a flange according to the present invention.
[0014] FIG. 2 is a top view showing a gasket according to the present
invention
placed adjacent the mating flange of the component illustrated in FIG. 1.
[0015] FIG. 3 is a side view of a tab retainer as it is inserted into an
aperh.tre
according to lines 3-3 of FIG. 2.
[0016] FIG. 4 is a side view of a second embodiment of a tab retainer.
[0017] FIG. 5 is a bottom view of a third embodiment of a gasket according to
the
present invention.
[0018] FIG. 6 is a side view of a tab retainer as it is inserted into an
aperture
according to lines 6-6 of FIG. 5.
[0019] FIG. 7 is a side view of the gasket according to lines 7-7 of FIG. 5.
-4-
Express Mail Label No. EL781402788US
CA 02350840 2001-06-15
60680-1475 (5459-1 VIC) PATENT
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0020] In FIG. 2, a gasket 20 is shown installed adjacent a first mating
flange 22
on an exhaust manifold 23, the manifold being illustrated in FIG. 1. The
gasket 20
includes a plurality of bolt holes 24 and exhaust gas flow holes 26 that
correspond to
similar holes in the first mating flange 22. The mating flange 22 defines a
first outer
periphery 28, and the gasket 20 defines a second outer periphery 30. As can be
seen
in FIG. 2, the first outer periphery 28 fiilly encloses the second outer
periphery 30.
As a result, the gasket 20 covers less than the full extent of the mating
flange 22.
Because of the arrangement of the flow holes 26, the length L of the gasket 20
is
1 o greater than the width W of the gasket.
[00211 Because seals on the exhaust manifold must withstand high temperatures,
the gasket 20 is typically fonned from metal, and usually includes multiple
metal
layers. Typically, the metal layers are made from resilient steel, and all
layers of the
gasket 20 are sized and shaped to fit and seal a corresponding mating surface.
The
outermost (i.e. top and bottom) layers (not shown) of the gasket 20 may
further
include embossments, folds or any other surface feature designed to improve
fit, wear
and sealing ability of the gasket.
[0022] According to the present invention, at least one layer of the gasket 20
includes at least two integral tabs 32 formed along the second outer periphery
30. The
two tabs 32 are spaced from each other to prevent rotation of the gasket
relative to the
first mating flange 22 once the gasket 20 is installed. The first mating
flange 22
includes at least two apertures 341ocated within the first outer periphery
that are sized
and positioned to receive the tabs 32. Preferably, the tabs 32 are formed
along the
outer periphery of the gasket 20 parallel to the width W of the gasket 20,
thereby
allowing the tabs 32 to flex within the apertures 34 and account for linear
tolerances
of the apertures and for gasket tolerances. Moreover, because the apertures 34
are
located within the first outer periphery of the first mating flange 22, the
gasket itself
does not cover the entire surface of the first mating flange 22. Instead, the
gasket 20
is smaller than the first mating flange 22, thereby requiring less material
for
fabrication.
[0023] Prior to assembly of the gasket 20 against the first mating flange 22,
the
tabs 32 are bent generally perpendicular relative to the gasket 20. The gasket
20 is
-5-
Express Mail Label No. EL781402788US
CA 02350840 2001-06-15
60680-1475 (5459-1 VIC) PA TENT
then placed adjacent the first mating flange 22 so that the tabs 32 align with
and are
inserted into the apertures 34. The tabs 32 are sized to frictionally engage
the inner
surface 36 of the apertures 34 and to thereby retain the gasket 20 in place
against the
first mating flange 22. Thus, an outermost periphery of tabs 32 in an
uncompressed
state is greater in dimension than a corresponding inner surface of the
apertures 34.
[0024] The tabs 32 may be formed into any geometric shape that is convenient
to
manufacture and that achieves a tight interference fit within appropriately
sized
apertures 34. Most preferably, as seen in FIG.3, the tabs 32 are formed from
two
contoured legs 38 that are separated to form a slot 40 between the tab legs
38. Each
1o tab leg 38 further includes a contoured tip 42 located at a distal end 44
of each tab leg
38.
[0025] The contoured tip 42 of each tab leg is preferably formed into a sloped
portion 46 that slopes laterally outwardly from the distal end 44 along an
outside edge
48 of each tab leg 38. Each sloped portion 46 terminates in a contoured,
laterally
outwardly extending protrusion 50. Thus, a protnision 50 is located at either
side of
the tab 32. As the tab 32 is inserted into the aperture 34, a portion the
sloped portion
46 contacts the inner surface 36 of the aperture 34, forcing the tab leg 38 to
gradually
compress laterally inwardly as it is inserted. Thus, the sloped portion 46
aids in pre-
loading the tab legs 38 while making insertion into aperh.ire 34 easier. The
protrusion
50 is sized to create an interference fit when placed in contact with the
inner surface
36 of the aperture 34, but is small enough to be easily inserted within the
aperture 34.
[0026] As noted above, the tab legs 38 are separated to form a slot 40 between
the
tab legs. Formation of the slot 40 allows the slight inward deformation of
each
resilient tab leg 38 as it is inserted into the aperture 34. The slot 40 also
allows each
tab leg 38 to deform independently of the other tab leg, so that the tab legs
38 in
combination are able to self adjust to the actual diameter of the aperture 34.
The size
of the slot 40 also allows the tab legs 38 to adjust for minor variations in
the location
of the apertures, thus providing a suitable tolerance.
[0027] In assembling a gasket 20 to a first mating flange 22, the tabs 32 are
bent
generally perpendicular relative to the gasket 20, so that the tabs 32 are
positioned
generally vertical to the width of the gasket. As applied to the preferred
embodiment,
the tab legs 38 are thus positioned vertical to the width of the gasket. The
gasket 20 is
-6-
Express Mail Label No. EL781402788US
CA 02350840 2001-06-15
60680-1475 (5459-1 VIC) PATENT
then placed adjacent the first mating flange 22 so that the tabs 32, including
the tab
legs 38, align with and are inserted into the apertures 34. As the tabs 32 are
inserted
into the apertures 34, the sloped portion 46 first contacts the inner surface
36 of
aperture 34. As the tabs 32 are further inserted into the apei-ture 34, the
tab legs 38
are independently forced to deform slightly inwardly. When the tab legs 38
have
been fully inserted into the aperture 34, only the protrusions 50 contact the
inner
surface 36 of the aperture 34. The resilient tabs maintain a slightly
laterally inwardly
deformed position, thereby applying a force laterally outwardly against the
inner
surface 36 of the aperture 34. The outward force applied through the
protrusions 46 is
1o sufficient to cause a tight interference fit of the tabs 32 within the
aperture 34 such
that the entire gasket 20 is maintained in position adjacent the first mating
flange 22.
The first mating flange 22 may then await assembly or shipment to a location
for
assembly at a later time without the gasket 20 becoming dislodged from it.
[0028] Because the apertures 34 are formed inside the configuration of the
mating
component, i.e. within the first outer periphery, a gasket 20 formed according
to the
present invention uses less material, thereby reducing cost. The resilient tab
legs 38
deform independently when inserted into the corresponding apertures 34 such
that
insertion of the legs 38 into corresponding apertures 34 positively locates
the gasket
in place against the mating flange 22. The combination of the tab legs 38, the
slot
20 40 and the protrusions tabs 32, when placed into frictional engagement with
the inner
surface 36 of the apertures 34, effectively retains the gasket 20 in place
against the
first mating flange 22. Thus, the configuration of the resilient legs 38
produces a tight
interference fit within the apertures 34. The gasket 20 is therefore held
tightly in
place by the tab legs 38. Because the tab legs 38 are also positioned vertical
to the
width of the gasket, the tab legs 38 may deform to allow for adjustment of the
gasket
relative to the mating flange, thereby accounting for linear tolerances of the
apertures
and for overall gasket tolerances. And finally, because the tabs 32 are formed
as part
of a metal layer of the gasket 20, both manufacture and assembly are
simplified
because no separate clips are required to attach the gasket 20 to the first
mating flange
3o 22.
[00291 A second preferred embodiment of a tab 32' is illustrated in FIG. 4.
Tab
32' comprises a serrated side edge 52 terminating at a plurality of resilient
points 54.
-7-
Express Mail Label No. EL781402788US
CA 02350840 2001-06-15
60680-1475 (5459-1 Y70 PATENT
Each point 54 extends upwardly and is angled with respect to an adjacent
valley 56
such that tab 32 may be easily inserted into mating aperture 34 as the points
54 bend
inwardly. However, each point 54 digs into the inner periphery 36 of the
mating
aperture 34 upon attempted removal of tab 32'.
[0030] A third alternative embodiment of the invention is disclosed in FIGS.
5, 6
and 7, showing a two-layer exhaust manifold gasket 120. While a two-layer
design is
illustrated, a three or more layer design is also within the scope of the
invention.
Gasket 120 includes a plurality of bolt holes 124 and gas flow holes 126 that
correspond to similar holes in a mating component. Like the first two
embodiments,
the layers of gasket 120 may further include embossments, folds or other
sealing
features. Because seals on the gasket must withstand high temperature and
resist
chemical attack, gasket 120 is preferably formed of a metal, and more
preferably
stainless steel. When formed from stainless steel, however, modifications to
the
production tooling may be required in view of the material characteristics.
[0031] According to the third embodiment, at least one metal layer of the
gasket
120 includes at least two integral tabs 132. Each tab 132 is formed as a
continuation
of the metal layer along an inner periphery 130 of a mounting aperture 131.
Permitting the tab to be formed as a continuation of a metal layer allows the
shape of
the tab to be formed in the same manufacturing operation. For example,
mounting
apertures 131, tabs 132, bolt holes 124 and gas flow holes 126 may be formed
in the
same stamping operation. As with the embodiments discussed above, tabs 132 are
bent generally perpendicular relative to gasket 120 so that tabs 132 are
positioned
generally vertical to the width of gasket 120. Additionally, tabs 132 are
spaced apart
to prevent rotation of gasket 120 once it is installed. The geometric shape of
tabs 132
is preferably substantially similar to tabs 32 in the first embodiment or,
alternatively,
may be formed substantially similar to tabs 32' in the second embodiment.
However,
it is within the scope of this embodiment that tabs 132 may be formed into any
geometric shape that is convenient to manufacture and that achieves a tight
interference fit within a mating aperture 134. The assembly of gasket 120 on a
mating
flange is substantially similar to the first embodiment as described above.
Moreover,
as with the earlier embodiments, tab legs 138 may deform to allow for
adjustment of
the gasket relative to the mating flange.
-8-
Express Mail Label No. EL781402788US
CA 02350840 2001-06-15
60680-1475 (5459-1 VIC) PA TENT
[0032] Accordingly, the present invention provides a gasket design that
incorporates integral tabs formed as a continuation of a gasket layer to
locate and
retain the gasket on an engine component. The use of integral tabs eliminates
the
need to use clips to attach the gasket to the gasket-attaching portion of the
component.
While the use of integral tabs has been described in relation to an exhaust
gasket, it is
recognized that the present invention may be incorporated into other engine
gaskets,
such as a head gasket, to retain the gasket in place prior to assembly of the
mating
component.
[0033] Although certain preferred embodiments of the present invention have
lo been described, the invention is not limited to the illustrations described
and shown
herein, which are deemed to be merely illustrative of the best modes of
carrying out
the invention. A person of ordinary skill in the art will realize that certain
modifications and variations will come within the teachings of this invention
and that
such variations and modifications are within its spirit and the scope as
defined by the
claims.
-9-
Express Mail Label No. EL781402788US
