Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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1 VIBRATION ISOLATION AND SEALING GASKET
The present invention relates generally to systems for
isolating covers from vibratable bases as shown in the Canadian
co-pending application Ser. No. 273,805 and more particularly to
a vibration isolation and sealing gasket to be used in such a
system.
In the past, most vibration isolation systems have relied on
trial and error methods of isolation by adding different materials
between a cover and its associated vibratable base, and attempts
to reduce bolt transmitted vibrations by using the same resilient
material in washers between the bolt heads and the cover as in
the gaskets have not been entirely successful because the compres-
sion necessary for proper sealing reduced the isolation capabili-
ties of the gaskets. Further, assembly of these systems is time
consuming because of the number of separate components required.
Summary of the Invention
The present invention provides a vibration isolation and
sealing gasket, a sealing portion of which is insertable between
a cover and a vibratable base, and an intermediate portion of
which includes toroidal protrusions insertable through clearance
holes in the cover to be convolutedly compressed by the tighten-
ing of the bolts to form grommets under the bolt heads. The
gasket includes integrally molded sleeves in the protrusions to
limit the compression of the sealing and the protrusion portions
so as to provide the spring same rate in both portions upon
tightening of the bolt so as to maximize vibration isolation of
the cover as well as the sealing efficiency of the gasket.
The above and additional advantages of the present invention
will become apparent to those skilled in the art from a consider-
ation of the following detailed description of the preferred em-
bodiment taken in conjunction with the accompanying drawings.
-- 1 --
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1 Brief Description of the Drawings
Fig. 1 is a side view of an assembly incorporating a pre-
ferred embodiment of the present invention;
Fig. 2 is a cross-sectional view taken along line 2--2 of
Fig. l;
Fig. 3 is a cross-sectional view taken along line 3--3 of
Fig. l;
Fig. 4 is a side view of an assembly incorporating an alter-
nate preferred embodiment of the present invention;
Fig. 5 is a cross-sectional view taken along the line 5--S
of Fig. 4;
Fig. 6 is a cross-sectional view taken along the line 6--6
of Fig. 4; and
Fig. 7 is an isometric view of a portion of the alternate
preferred embodiment.
Description of the Preferred Embodiment
Referring now to Fig. 1, therein is shown a vibration isola-
tion system 10 which includes a vibratable engine or base 12
having an engine cavity or opening 14 provided therein, a gasket
16 encircling the opening 14, and a cover 18 covering the opening
14 and secured to the vibratable base 12 by bolts 22 passing
through washers 20.
Referring now to Fig. 2, therein is shown a cross-section of
the gasket 16 with the bolt 22 in an untightened position. The
bolt 22 having a bolt head 24 and a threaded portion 26 is lightly
threaded into a threaded hole 28 in the vibratable base 12. The
gasket 16 includes a pair of oblong bead-shaped sealing portions
30 and 32 which have similar cross-sections and which are connec-
ted by a rectangular flange portion 34. The flange portion 34
includes a plurality of cylindrical protrusions 36 axially per-
pendicular to the plane of the bead-shaped portions 30 and 32.
Each of the protrusions 36 has a through hole 37 in which is
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1 molded a cylindrical sleeve 38 shich is generally metallic. The
protrusions 36 further have annular relief grooves 40 provided
therearound proximate the flange portions 34, of substantially
the same diameter as clearance holes 42 provided in the cover 18.
As may be seen by reference to Fig. 3, when the bolt 22 is
tightened into the threaded hole 28 until the washer 20 abuts the
sleeve 38, the gasket 16 will be compressed until the bead-shaped
portions 30 and 32 are deformed to form sealing surfaces 46 and
48, and 50 and 52, respectively, and the protrusion 36 will be
deformed into a convoluted configuration or grommet as designated
by the numeral 44.
To assemble the vibration isolation system 10, the protru-
sions 36 are first press fit into the clearance holes 42 in the
cover 18 and held in place thereby. The cover 18 with the gasket
16 held in place is then placed against the vibratable base 12
and the bolts 22, encircled by the washers 20, are inserted
through the protrusions 36 and the sleeves 38 to be threaded into
the threaded holes 28. As the bolts 22 are tightened down to a
position set by the length of the sleeve 38, the gasket 16 will
deform so as to form the convolutions 44 above the cover and the
sealing surfaces 46, 48, 50, and 52 between the cover 18 and the
base 12.
The durometer of the gasket 16 as well as the wall thickness
of the protrusions 36 are selected so as to prove approximately
equal spring rates between the washer 20 and the cover 18 and
between the cover 18 and the vibratable base 12 as explained in
greater detail in the co-pending Canadian application Ser. No.
273,805 which is herewith incorporated by reference thereto. And
further, as evident to those skilled in the art from a reading of
the co-pending application, the sleeve 38 length is sized so as
to provide a minimum compression of the gasket 16 between the
cover 18 and the vibratable base 12 of at least 10~ of the un-
compressed height.
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1 Referring now to Fig. 4, therein is shown an alternate
preferred embodiment of a vibration isolation system 110 which
includes a vibratable engine or base 112 having an engine cavity
or opening 114 provided therein, a gasket 116 encircling the
opening 114, and a cover 118 covering the opening 114 and secured
to the vibratable base 112 by bolts 122 passing through washers
120.
Referring now to Fig. 5, therein is shown a cross section of
the basket 116 which includes an oblong bead-shaped sealing
portion 130 with the major axis of the oblong perpendicular to
the surface of the base 112 and a stabilizing band 132 embedded
in the sealing portion 130 which is of a material such as a metal
which is rigid enough to withstand any tendency of the major axis
of the sealing portion 130 to move out of perpendicularity with
the surface of the base 112.
Referring now to Fig. 6, therein is shown a cross-section of
the gasket 116 in the area of one of the bolts 122 which is
threaded into a threaded hole 128 in the base 112. In this area,
the gasket 116 includes a flange portion 134 encircled by the
sealing portion 130 and having one of a plurality of cylindrical
protrusions 136 which are positioned axially perpendicular to the
flange portion 134 and perpendicular to the plane of a closed
loop defined by the gasket 116. The protrusion 136 and the
flange portion 134 contain a through hole into which is molded a
cylindrical sleeve 138. The protrusions 136 further have an
annular relief groove 140 provided therearound proximate the
flange portion 134, of substantially the same diameter as clear-
ance holes 142 provided in the cover 118.
The bolt 122 is shown tightened into the threaded hole 128
until the washer 20 abuts the sleeve 138 compressing the gasket
116 until the oval bead-shaped sealing portion 130 is deformed to
form sealing surfaces 146 and 148 and the protrusion 136 i9
105865Z
1 deformed into a convoluted coniguration or isolating grommet as
designated by the numeral 144.
To assemble the vibration isolation system 110, the protru-
sions 136 of the gasket 116 are first press fit into the clearance
holes 142 and then held in place thereby. The cover 118 with the
gasket 116 held in place is then placed against the vibratable
base 112 and the bolts 122, encircled by the washers 120, are
inserted through the protrusions 136 and the sleeves 138 to be
threaded into the threaded holes 128. As the bolts 122 are
tightened down to the position set by the length of the sleeve
38, the gasket 116 will deform so as to form the convolutions 144
above the cover and the sealing surfaces 146 and 148 and between
the cover 118 and the base 112.
The durometer of the gasket 116 as well as the wall thickness
of the protrusions 136 are selected so as to provide equal spring
rates between the washer 120 and the cover 118 and between the
cover 118 and the vibratable base 112 as explained in greater
detail in the copending application Ser. No. 273,805. Ana fur-
ther, as also explained in the copending application, the sleeve
138 length is sized so as to provide a`minimum compression of the
gasket 116 between the cover 18 and the vibratable base 12 of 10%
of the uncompressed height.
Referring now to Fig. 7, therein is shown an isometric of a
portion of the gasket 116 in the uncompressed condition in the
area around one of the protrusions 136.
While the invention has been described in conjunction with a
specific embodiment, it is to be understood that many alterna-
tives, modifications, and variations will be apparent to those
skilled in the art in light of the aforegoing description.
Accordingly, it is intended to embrace all such alternatives,
~~modifications, and variations which fall within the spirit and
scope of the appended claims.
