Gasket construction

A head gasket assembly (18) is used for sealing a joint between a cylinder block (12) and a cylinder head (14). At least portions of the head gasket assembly (18) must withstand high temperatures, high pressures and be flexible for sealing fluid passages such as lubricating oil and cooling water mixtures. The present head gasket assembly (18) is comprised of a main gasket body (40) constructed of a sealing material (46) having a plurality of apertures (48,50,52) positioned therein. A portion of the plurality of apertures (48,50,52) includes a combustion opening (52) having a first ring (54) positioned in the periphery of the combustion opening (52). A plurality of tape strips (60) having an end portion (62) attached to a side of the sealing material (46), partially surrounding the fire ring (54) and another end portion (64) attached to the other side of the sealing material (46). Thus, the flexible main gasket body (40) and the rigid fire rings (54 ) are fixedly attached together and provide a head gasket assembly (18) which has very good handleability, sealability and functional characteristics.

DESCRIPTION 
1. Technical Field 
This invention relates to gaskets, and more particularly relates to the 
structure for securingly retaining a sealing element or fire ring to the 
body of a gasket having the grommet or fire ring positioned in a aperture 
of the body. 
2. Background Art 
There are a variety of head gaskets known in the prior art. Head gaskets 
generally are made of relatively thin, generally flat bodies which define 
a plurality of apertures, including oil and water bores and combustion 
openings. 
The sealing of an internal combustion engine is a complex and difficult 
matter. High temperatures and pressure which are localized and which vary 
across the surface of the gasket between the block and the head require 
differing treatments at different areas, and usually require the use of 
sealing aids such as grommets, elastomeric seals, armoring and the like. 
As an example, in high compression engines operating at high temperatures 
and high pressures, it has been a practice for a number of years to 
provide head gaskets with armoring adjacent the cylinder or combination 
openings to seal the combustion openings and to protect the remainder of 
the gasket from the effects of the high temperature and pressure. Early 
armor covered the entire gasket surface as well as the edges of the 
combustion openings. More recently, the armor has been used to embrace 
only the edges of the gasket body adjacent the combustion openings to seal 
the head and block around the combustion opening. 
Frequently, the gasket body itself is made of thin elastomeric bonded 
sheets laminated to a central metallic core. In such gaskets the armoring 
has generally been comprised of a U-shaped annulus which overlies the 
periphery of the main gasket body adjacent the combustion opening and 
which encloses one or more wire rings. An example of such an arrangement 
is disclosed in U.S. Pat. No. 4,331,336 issued to Daniel E. Czernik et al 
on May 25, 1982, The U-shaped annulus extends to the periphery of the 
combustion opening in the body and is retained by a plurality of tabs 
which overlap the peripheral edge of the gasket body supporting the 
armoring within the combustion opening. 
In another U.S. Pat. No. 4,605,236 issued to Keiichi Tsuchihashi et al on 
Aug. 12, 1986 a head gasket is disclosed in which a grommet is generally 
U-shaped in cross-section. The grommet has spaced ends at least one of 
which is bent inwardly to engage a bore wall of the gasket to securely 
hold the grommet in place within a gasket opening. 
The above-listed patents disclose a U-shaped flange for attaching a solid 
ring to a gasket body. The thin walled U-shaped flange may become 
destroyed or burnt through by the high temperatures and high combustion 
pressures within the combustion chamber of an engine. Thus, a leak path is 
created from the combustion chamber and the remainder of the gasket is no 
longer protected from the high temperatures and high pressures. Another 
problem which is sometimes evident in this type of construction is that 
the heat from the combustion chamber is transmitted through the thin 
walled U-shaped flange into the gasket material. When this occurs, the 
heat causes laminated elastomeric bonded sheet material to harden reducing 
the sealing characteristics of the material and eventual failure of the 
heat gasket. 
In an attempt to alleviate the heat transferring problem and the failure of 
the thin walled U-shaped flange described above, U.S. Pat. No. 4,376,539 
issued to John W. Baldacci on Mar. 15, 1983 discloses a multilayer gasket 
main body defining water and oil apertures and a combustion opening and a 
fire ring is supported in the combustion opening. The fire ring is 
supported in the combustion opening by individual U-shaped tabs. The tabs 
are bonded to the annulus of the fire ring by a spot-weld or adhesive mass 
and supports the annulus in the combustion opening. 
Another problem which has been defined when using the above-described head 
gasket designs is that the thin walled steel flange holding the combustion 
seal or wire ring in place during assembly absorbs some of the bolt load 
during the torquing process. The flange further absorbs some of the load 
during the thermal cycling of the engine. Because the flange absorbs a 
portion of the load, the assembled load into the wire ring is reduced. 
This is not a desirable characteristic for some head-to-block joints 
because the load absorbed in the flange is not available to be applied to 
the wire ring. Some recently designed head gaskets have reduced the amount 
of flange overlapping the body of the gasket to minimize load taken away 
from the wire ring. In other head gaskets the flange has been entirely 
eliminated. For example, in some head gaskets when the flange has been 
eliminated the wire ring is either glued directly to the gasket material 
or the wire ring has protrusions extending therefrom which are used to 
attach the ring to the gasket material. In a head gasket having a rather 
rigid core this process of attaching the wire ring to the gasket material 
has been rather successful. However, in gaskets wherein the core is more 
flexible or less rigid, the above described techniques for attaching the 
wire ring to the gasket material are less successful. 
The present invention is directed to overcoming one or more of the problems 
as set forth above. 
DISCLOSURE OF THE INVENTION 
In one aspect of the invention, a head gasket assembly has been adapted for 
use in an engine. The engine has a cylinder block and a cylinder head. The 
cylinder block has a combustion chamber, a plurality of threaded holes and 
a plurality of bores defined therein and the cylinder head has a plurality 
of bores therein corresponding to the threaded holes and at least a 
portion of the plurality of bores in the cylinder block. The head gasket 
assembly is comprised of a main gasket body having a center core, a 
sealing material attached to each side of the core and a plurality of 
apertures defined within the main gasket body and extending through the 
sealing material and the core. The plurality of apertures include a 
combustion opening and at least a portion of the plurality of apertures 
correspond to the combustion chamber, the plurality of threaded holes and 
the plurality of bores in the cylinder block when in use. The head gasket 
assembly is further comprised of a fire ring positioned in each combustion 
opening and means for attaching the fire ring to the sealing material 
prior to being installed in the engine. The means for attaching includes a 
plurality of tape strips having an end portion attached to a side of the 
sealing material, partially surrounding the fire ring and having another 
end portion attached to another side of the sealing material. 
In another aspect of the invention, a head gasket assembly is adapted for 
use in an engine. The engine has a cylinder block and a cylinder head. The 
cylinder block has a combustion chamber, a plurality of threaded holes and 
a plurality of bores defined therein. The cylinder head has a plurality of 
bores defined therein corresponding to the threaded holes and at least a 
portion of the plurality of bores in the cylinder block. The head gasket 
assembly is comprised of a main gasket body being constructed of a sealing 
material and having a plurality of apertures defined within the main 
gasket body and extending through the sealing material. The plurality of 
apertures include a combustion opening and at least a portion of the 
plurality of apertures correspond to the combustion chamber, the plurality 
of threaded holes and the plurality of bores in the cylinder block when in 
use. The head gasket assembly is further comprised of a fire ring 
positioned in each combustion opening and means for attaching the fire 
ring to the sealing material prior to being installed in the engine. The 
means for attaching includes a plurality of tape strips, each tape strip 
has an end portion attached to a side of the sealing material, partially 
surrounds the fire ring and has another end portion attached to the other 
side of the sealing material. 
In another aspect of the invention, an engine is comprised of a cylinder 
block and a cylinder head. The cylinder block has a combustion chamber, a 
plurality of threaded holes and a plurality of bores defined therein. The 
cylinder head has a plurality of bores defined therein corresponding to 
the threaded holes and at least a portion of the plurality of bores in the 
cylinder block. A head gasket assembly is sealingly positioned between the 
cylinder block and the cylinder head. The head gasket assembly includes a 
main gasket body being constructed of a sealing material and having a 
plurality of apertures defined within the main gasket body extending 
through the sealing material. The plurality of apertures include a 
combustion opening and at least a portion of the plurality of apertures 
corresponding to the the combustion chamber, the plurality of threaded 
holes and the plurality of bores in the cylinder block. A fire ring is 
positioned in each combustion opening and means for attaching the fire 
ring to the sealing material prior to being installed in the engine. The 
means for attaching includes a plurality of tape strips, each tape strip 
has an end portion attached to a side of the sealing material, partially 
surrounds the fire ring and has another end portion attached to the other 
side of the sealing material. 
In another aspect of the invention, a gasket assembly includes a main 
gasket body having a sealing material and having a plurality of apertures 
defined within the main gasket body and extending through the sealing 
material. A sealing element is position in at least a portion of the 
plurality of apertures. And, the gasket assembly further includes means 
for attaching the sealing element to the sealing material. The means for 
attaching includes a plurality of tape strips and each of the tape strips 
has an end portion attached to a side of the sealing material, partially 
surrounds the sealing element and has another end attached to another side 
of the sealing material.

BEST MODE FOR CARRYING OUT THE INVENTION 
As best shown in FIG. 1, an internal combustion engine 10 includes a 
cylinder block 12, and a cylinder head 14 removably attached to the 
cylinder block 12 by a plurality of bolts 16 in a conventional manner. A 
gasket which in this application is a head gasket assembly 18 is sealingly 
positioned between the cylinder block 12 and the cylinder head 14. 
The block 12 defines a plurality of apertures including a plurality of 
combustion cylinders or chambers 20 each having a liner 22 therein, a 
plurality of oil and water bores 24 and a plurality of threaded holes 26, 
of which only one is shown. As an alternative, the block 12 could have the 
plurality of combustion cylinders or chambers 20 defined directly therein. 
The head 14 defines a combustion chamber portion 28 overlying each chamber 
20, and further defines a plurality of oil and water bores 30 which are 
aligned with the complementary bores 24 in the block 12. The head 14 
further defines a plurality of bores 32 therethrough which are aligned 
with the plurality of threaded holes 26 in the block 12. Each of the 
plurality of bolts 16 pass through one of the plurality of bores 32 in the 
head 14 and is threadedly engaged into a corresponding one of the 
plurality of threaded holes 26 in the block 12. Each of the plurality of 
bolts 16 serve as a means 34 for torquing and compressing the head gasket 
assembly 18 into sealing engagement with the block 12 and had 14. 
As best shown in FIGS. 2, 3 and 4, the head gasket assembly 18 includes a 
generally rectangular shaped main gasket body 40. The main gasket body 40 
includes a center metallic core 42. The core 42 may consist of a rather 
flexible perforated plate 44 or as an alternative the plate may be 
relatively flat, ridged and non-flexible. It is conventional to use a 
steel, copper or aluminum plate for the core material. Each side of the 
core 42 is attached to a heat-sensitive multilayer or composite sealing 
material 46. Examples of material used for the sealing material include a 
soft metallic or non-metallic material, such as mild steel, a nitrile 
rubber, a heat curable liquid silicone, a fluoroelastomer, a thermoplastic 
resin having a filler therein or a graphite facing. The sealing materials 
46, if required, are impregnated with a conventional temperature, oil and 
water resistant impregnate. Other suitable materials may be used for 
either the core 42 of the sealing material 46. After the core 42 and the 
sealing material 46 have been bonded or affixed together, a plurality of 
apertures including oil passages and water passages 48 and bolt hole 
passages 50 are formed such as by punching through the core 42 and the 
sealing material 46. The plurality of passages 48 correspond to at least a 
portion of the appropriate plurality of oil and water bores 24 in the 
block 12 and to the appropriate plurality of oil and water bores 30 in the 
head 14. The bolt hole passages 50 correspond to the plurality of threaded 
holes 26 in the block 12 and the plurality of bores 32 in the head 14. 
Another portion of the plurality of aperture 48 are formed by the punching 
operation and include a plurality of combustion openings 52 which 
correspond to the plurality of combustion cylinders or chambers 20 in the 
block 12. Each of the plurality of combustion openings 52 have a sealing 
element or fire ring or wire ring 54 provided in each combustion opening 
52. The fire ring 54 is positioned at the periphery of the combustion 
opening 52 and is generally in contact with the sealing material 46. 
Depending on the engine or application, the wire ring to be used may be 
flat, round, elliptical or otherwise, and may be so shaped, as with flats 
or may be otherwise modified to any configuration. The fire ring 54 is 
constructed of a deformable material, such as annealed steel or copper. In 
this application, the fire ring 54 is formed by welding a wire into a 
circular ring having a welded joint. The wire is circular in cross-section 
and made of annealed stainless steel. The fire ring 54 is attached to the 
sealing material 46 of the main gasket body 40 by a means for attaching 58 
which includes a plurality of tape strips 60. An end portion 62 of each 
tape strip 60 is attached to one side of the sealing material 46. The tape 
strip 60 extends partially around the fire ring 54 and another end portion 
64 is attached to the other side of the sealing material 46. When placing 
the tape strip 60 around the wire ring 54, caution must be taken to place 
the tape strip 60 in the area away from the welded joint. In this 
application, an individual tape strip 60 is positioned near three of the 
bolt hole passages 50. This distribution provides an even spacing of 
approximately 120 degrees about the fire ring 54. Each of the plurality of 
tape strips 60 is made from a Teflon film having a thickness of 
approximately 0.05 mm and has a silicone adhesive having a thickness of 
approximately 0.04 mm attached to one side. As an alternative, the strip 
60 can be made of any appropriate material having sufficient strength and 
a relative small thickness. Furthermore, as an alternative, the adhesive 
can be made of an acrylic or rubber base provided the ability to remain 
attached to the sealing material is retained. In this application the 
strip has a length of approximately 18 mm, width of approximately 14 and 
mm and a total thickness of approximately 0.09 mm. A variety of criteria 
was developed in choosing the proper tape. For example, the tape strip 60 
must attach or bond well to the main gasket body 40 so that the main 
gasket body 40 and the wire ring 54 attached thereto will remain secured 
to each other during handling, the tape strip 60 must not affect 
combustion sealing and the tape strip 60 must be easily assembled to the 
gasket body 40. As an alternative the tape strip 60 may shear upon 
assembly of the cylinder head 14 to the cylinder block 12 when the torque 
is applied by the plurality of bolts 16. Or, as a further alternative, the 
tape strip 60 may stretch provided the combustion sealing is not affected. 
As a further alternative, the tape strips 60 can be used to attach other 
sealing elements 54 such as grommets or O-rings to any of the apertures 48 
within any type of a gasket 18 regardless of its position and use. 
As an alternative to the head gasket assembly 18 as described above, a 
second sealing material 70 may be applied to the sealing material 46. For 
example, as is best shown in FIGS. 2 and 4, a raised bead of the second 
sealing material 70 is applied to preestablished portions of the sealing 
material 46. It should be further noted that each of the strips 60 do not 
overlap the second sealing material 70 when assembled to the sealing 
material 46. In this application the second sealing material 70 is applied 
to only one side of the sealing material; however, as an alternative, the 
second sealing material 70 may be applied to both or either side of the 
sealing material 46. Examples of such areas or portions to have the second 
sealing material 70 applied thereto are around the plurality of apertures 
48 and about a portion of the periphery of the main gasket body 40. It 
should be noted that the raised bead of the second sealing material 70 is 
spaced from the plurality of apertures 48 and the periphery of the main 
gasket body 40. In this application the distance from the periphery of the 
main gasket body is about 2 mm, the distance from oil and water passages 
48 is at a minimum about 3 mm and the distance from the periphery of the 
combustion opening 52 is at least a distance greater than either of the 
distances from the periphery of the main body and the plurality of oil and 
water apertures 50. 
As an alternative and best shown in FIG. 5, the main gasket body 40 of the 
head gasket assembly 18 could be formed of a composite sealing material 46 
and the core 42 would be eliminated. The remainder of the head gasket 
assembly 18 would remain as described above. 
Industrial Applicability 
The head gasket assembly 18 is used to seal the joint between the cylinder 
block 12 and the cylinder head 14. The head gasket assembly 18 must 
perform several functions in order to satisfactorily seal the 
above-mentioned joint. For example, the sealing material 46 must be 
compressible but on the other hand resilient enough to remain in sealing 
contact between the cylinder block 12 and the cylinder head 14. The second 
sealing material 70 must also be compressible and resilient enough to 
remain in sealing contact between the sealing material 46 and the cylinder 
head 14. And lastly, the fire ring 54 must be compressible and resilient 
enough to remain in sealing contact between the cylinder block 12 and the 
cylinder head 14 even during the high temperature and high load being 
applied from the combustion cycle during the engine 10 operation. 
Experience has shown that one primary consideration to be concerned with 
when assembling the head gasket assembly 189 into the engine 10 is the 
handleability of the head gasket assembly 18. As the engine cylinder block 
12 is traveling down the assembly line, an assembler removes the head 
gasket assembly 19 from a shipping and receiving crate. The assembler 
carries the head gasket assembly 18 from the crate to the cylinder block 
12 and properly positions the gasket 18 relative to the cylinder block 12. 
After the gasket 18 has been positioned on the cylinder block 12, the 
cylinder head 14 is lowered on the gasket 18, the plurality of bolts 16 
are secured into the cylinder block 12, sealing and assembling the 
cylinder block 12, head gasket assembly 18, and the cylinder head 14 
relative to each other. After which, the engine 10 continues to travel on 
down the assembly line for further attachment of components. 
The head gasket assembly 18 is generally rectangular and has a length 
greater than its width by as much as 3 to 4 times the width. This rather 
long length and the flexibility of the head gasket body 40 make it 
difficult for the assembler to transport the gasket 18 from the crate to 
the engine block 12. The rigid characteristic of the fire ring 54 and the 
flexible characteristic of the main gasket body 40 tend to work against 
each other structurally trying to cause the two to separate during the 
transportation and assembly processes. Thus, the plurality of tape strips 
60 which are used to assembly the wire ring 54 to the sealing material 46 
of the main gasket body have been found to provide a intermediary between 
the rigid fire ring 54 and flexible main gasket body 40. 
Thus, the head gasket assembly 18 provides a rigid fire ring 54 to seal the 
high temperature and high pressures within the combustion chamber 20 and 
the omission of heat conducting flanges, or rigid overlapping devices for 
attaching the fire ring 54 to the sealing material 46 prevents the heat 
transfer into the sealing material 46 of the main gasket body 40. 
Furthermore, the omission of heat conducting flanges or rigid overlapping 
devices for attaching the fire ring 54 to the sealing material 46 
substantially reduces the load absorbed by the attaching devices and 
results in a more even and/or higher distribution of the load on the fire 
ring 54. The tape strips 60 further provides a transition joint between 
the rigid fire ring 54 and the flexible main gasket body 40 insuring a 
head gasket assembly which has very good handleability, sealability and 
functional characteristics. 
Other aspects, objects and advantages of this invention can be obtained 
from a study of the drawings, the disclosure and the appended claims.