JPH0599340A - Gasket - Google Patents

Abstract

PURPOSE: To prevent loosening of a bolt caused by loosening of gasket and to prevent deterioration of seal function of two elements without limiting the compression added on the gasket material. CONSTITUTION: Compressible inserts 17 are arranged in holes 10c of each bolt. These inserts are made in continuous or crack-attached annular shape, and have the same size as the thickness of the gasket body or are a little thinner than it. Each insert is connected with the gasket by plural drop-like elements 19 that are spaced by arranged and are made of elastomer materials or adhesive. Or each insert is kept in holes of each bolt with continuous beads made of the materials like the drop-like elements. The inserts can also be kept in holes of each bolt by a flange surrounding the inserts and connected with upper surface or lower surface of the gasket. In the case of the inserts attached with cracks, an inserts having an outer diameter bigger than the inner diameter of each bolt while loosening are formed and are kept in holes of each bolt with friction.

Description

Description: FIELD OF THE INVENTION The present invention generally relates to two
The present invention relates to gaskets which form a seal between individual parts, and more particularly to an improved gasket construction in which an annular insert is retained within each bolt hole so that the mating and compressive effects are produced by such mating parts. BACKGROUND OF THE INVENTION Gaskets are a well-known article designed to form a relatively leaktight seal between two mating parts such as the manifold and head of an internal combustion engine. It is typically intended for two parts, each having a flat surface placed adjacent to each other during use. During assembly of these parts, the gasket is located between the flat surfaces that mate with each other. Bolts or similar means are used to connect the two parts together and compress the gasket between the mating surfaces. When compressed in this manner, the gasket provides a relatively leak tight seal between the two parts. When compressed between two parts, the material of the gasket body is componentally deformed by the pressure exerted by the mating surfaces. Because the gasket has some amount of inherent resilience, the gasket material resists such compression and exerts a counter force on the two parts. This counterforce is transmitted to the bolts that tighten the two parts and frictionally screw these bolts into the threaded holes in the parts into which they are screwed. This frictional threading prevents undesired rotation of the bolt during use, thus preventing diminished compressive forces on the gasket. Such mounting of the bolt is especially important when the compressive load normally applied by the bolt to the gasket is relatively low. Ideally, the gasket material should remain elastic during use to keep the bolt from loosening as previously described. However, it has been found that the elasticity of the gasket material typically decreases in response to continued compression over a period of time. This phenomenon, called loosening of the gasket, reduces the elastic force exerted on the bolt by the gasket material. Therefore, the screwing through the friction of the bolt against the screw hole is also weakened. When the normal compressive load exerted by the bolt is relatively low, the looseness of the gasket loosens the bolt, reducing the sealing action between the two parts. Some amount of loosening occurs in all materials that are constantly under compression. However, it is well known that metallic and similar materials are less prone to loosening than the softer materials typically used to form gaskets. That is, it is well known to form a gasket in which hard steel washers are arranged in bolt holes. These hard steel washers reduce the aforementioned undesirable effects of gasket loosening by providing direct metal-to-metal contact between the washer and the mating parts. However, such hard steel washers deform very little when compressed by the mating parts, limiting the amount of compression that can be applied to the gasket material. The resulting gasket seal is therefore adversely affected. Also, for some gaskets, it is desirable to vary the amount of compressive force exerted by some or all of the bolts. Such changes in bolt load depend on the location of the bolt holes in the gasket, the overall shape of the gasket and the shape of the parts thus joined. The solid steel washer described above, in these cases, especially when the normal compressive load applied to the gasket from the bolt is relatively low,
It has not been found to work extremely well. That is, some means formed of ordinary gasket material to ensure proper sealing, yet to allow the bolted components to come into direct contact and to be positioned at the bolt holes to prevent loosening of the gasket. It is desirable to provide a gasket with a body that forms a. SUMMARY OF THE INVENTION The present invention is directed to an improved gasket construction intended with the above concepts in mind. The gasket comprises a body formed of a resilient gasket material with a plurality of bolt holes formed therethrough. A compressible insert is located within each bolt hole. These inserts generally have a continuous or scored annular shape and are formed of a relatively soft material having a hardness in the range of 15 RB to 75 RB. The thickness of each insert may be equal to or slightly less than the thickness of the gasket body. The insert is connected to the gasket body by a plurality of separate spaced apart drops of elastomeric material or adhesive.
Alternatively, a continuous bead of such a material may be used and each insert retained within the hole. Each insert also surrounds these inserts and is retained in the hole by flanges that engage the top and bottom surfaces of the gasket. Finally, when the insert is to be cracked, an insert having a looser outer diameter than the inner diameter of the hole and being retained in the hole by friction is formed. It is an object of the present invention to provide an improved gasket having a body formed of conventional gasket material which ensures a proper sealing action. Another object of the present invention is to provide such an improved gasket with a compressible insert located at the location of the bolt holes to directly contact the joined parts and prevent loose bolt loads. To provide. It is a further object of the present invention to provide such an improved gasket which is simple and inexpensive to manufacture. Other objects and advantages of the present invention will be apparent from the following description thereof with reference to the accompanying drawings of a preferred embodiment. FIG. 1 illustrates a portion of a gasket 10 according to the present invention. The gasket 10 has a plurality of large holes 10a formed therethrough. Each hole 10a is provided so as to allow gas or fluid to flow when the gasket 10 is attached between two parts as described later in detail.
A thin metallic flange (not shown) is provided around some and all of each hole 10a. The gasket 10 further has a plurality of relatively small holes 10c formed therethrough. Each hole 10c has two holes, as described later in detail.
A bolt or similar means is provided through which the individual pieces are connected together. As is apparent from FIG. 2, the gasket 10
Is generally flat and the upper and lower layers of gasket material 1
It comprises a central metallic core 11 arranged between 2 and 13. The heart 11 is in this well known as layer 1
Make a hole to tighten 2,13. Each layer 12, 13
Can be formed of any suitable gasket material such as expanded graphite. The gasket 10 further comprises sealing beads 15, 16 printed on the surfaces of the upper and lower layers 12, 13. The sealing beads 15 and 16 are
It is formed from a compressible elastomeric material such as nitrile rubber. The sealing bead 15.16 is the gasket 10.
Extending around holes 10a and other areas to enhance the sealing properties of gasket 10. An annular insert body 17 is arranged in each of the smaller bolts 10c. Each insert 17
Are continuous as shown in the two left-hand side 10c of FIG.
Alternatively, as shown in the two holes 10c on the right side of FIG. 1, a crack may be formed. In each case, each insert 17
It is made of a material that is harder than the material used to form each gasket 12, 13 and still relatively soft and compressible. For example, insert 17 should be 15 RB
Through annealed low carbon steel with a hardness in the range of 75 to 75 RB. If the insert 17 is made of a metallic material, the insert may be made of the same material as the two parts between which the insert is placed for use. Although shown as circular in cross section, the insert 17 may be formed of wire having other cross sectional shapes, such as square wire. The thickness of the insert 17 may be equal to or slightly thinner than the thickness of the gasket 10. Means are provided for retaining the insert 17 in the hole 10c. As shown in FIGS. 1 and 2, each insert 17 is connected to the gasket 10 by a plurality of spaced apart drops 19 of compressible elastomeric material. In the illustrated embodiment, four drops 1 are equally spaced from each other for each insert 17.
9 is provided. For convenience, the droplets 19 are the sealed beads 1
The sealing beads 15 and 16 may be formed of the same material as that of the sealing beads 15 and 16, and may be attached at the same time. Each drop 1
9 encloses each portion of insert 17 and gasket 10 partially spaced around it and retains insert 17 within hole 10c. Prior to installation, each drop 19 need only exert a sufficient amount of force to retain the insert in hole 10c during normal shipping and handling of gasket 10. Alternatively, each insert 17 may be retained within hole 10c by a continuous bead of elastomeric material (not shown). An adhesive such as an epoxy resin may be used instead of the elastomeric material. The insert 17 is also mechanically retained within the hole 10c by a similar flange (not shown) with the flange 10b disposed around the hole 10a. Such a flange surrounds the insert 17 and engages the upper and lower surfaces of the gasket 10 to retain the insert 17 within the hole 10c. Each flange is formed of a malleable material that deforms with the insight 17 when compressed as described below. The use of an elastomeric material or adhesive or flange to retain insert 17 in hole 10c is not necessary if insert 17 is creviced. Rather, it is sufficient to form such a split insert 17 having an outer diameter when loosened that is larger than the inner diameter of the hole 10c. To install such an insert 17, the insert is first compressed to a diameter smaller than the diameter of the hole 10c. The compressed insert 17 is then inserted into the hole 10c. Finally, insert 17 is released and expanded to frictionally engage the inner surface of hole 10c. This frictional engagement allows the insert 1 to be inserted into the hole 10c without the use of any other means.
Sufficient to hold 7. FIG. 3 shows the gasket 10 disposed between a pair of components such as the manifold 30 and head 31 of an internal combustion engine. The gasket 10 is compressed between the flat combinations 30a and 31a of the manifold 30 and the head 31. The bottle 32 (which is bolted like a plurality) passes through an unthreaded hole 33 in the manifold 30,
It extends through the gasket hole 10c and is screwed into the screw hole 34 in the head 31. When tightening, bolt 32
Connects the manifold 30 to the head 31. Therefore, the gasket 10 is compressed between the mating surfaces 30a, 31a. Due to this compression, the sealing beads 15,1
6 is pressed against the gasket material layers 12, 13. Further, by this pressing, the insert 117 is attached to the two members 30, 31.
Compress in with the rest of gasket 10. The compression of the sealing beads 15, 16 and the gasket material layers 12, 13 creates a sealing action between the two members 30, 31 and allows gas or fluid to flow without leaks through the holes 10a. Since the insert 17 is formed of a relatively soft material, this compression causes the circular cross-sectional shape to be transformed into the substantially oval cross-sectional shape illustrated in FIG. 3 when loosened. The elongated upper and lower surfaces of the deformed insert 17 are the mating surfaces 30a, 3 of the respective parts 30, 31.
1a is engaged. The amount of deformation of each insert 17 changes depending on the load applied by the corresponding bolt 32. Such bolt loads may be varied between the holes 10c of the gasket 10 if desired, depending on the location of the holes 10c, the shape of the gasket 10 and the configuration of each component 30, 31. Each separate insert 17 adapts to such a change in the bolt load and keeps direct contact between the components 30 and 31. Insert 17 and gasket material layer 12,
When 13 and 13 are deformed, they experience internal compressive stresses that resist such compression. As time passes, the compressive stress in the gasket material layers 12 and 13 decreases as described above. However, the insert 17 will not permanently deform significantly under normal conditions. Rather insert 1
7 continues to receive compressive stress to maintain the frictional engagement of the bolt 32 with the threaded hole 34. It is therefore clear that the insert 17 holds the bolt load and the rest of the gasket 10 seals between the mating surfaces 30a, 31a of each part 30, 31. Although the principle and system of operation of the present invention have been described with reference to the preferred embodiments, it is obvious that the present invention can be modified in various ways without departing from the spirit thereof.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial plan view of a gasket according to the present invention. FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG. FIG. 3 is an enlarged vertical cross-sectional view of the gasket portion illustrated in FIGS. 1 and 2 shown compressed between two mating components of an internal combustion engine. [Explanation of reference numerals] 10 gasket 10c hole 17 insert 19 elastomeric material (droplets)

Claims (1)

Claim: What is claimed is: 1. A body formed of a gasket material, the body having a hole formed therethrough, an insert disposed in the hole, and a retainer for retaining the insert in the hole. An insert and an elastomeric material that partially surrounds a portion of the gasket material. 2. The insert comprises 15 RB to 75
The gasket of claim 1 formed of a material having a hardness in the range of RB. 3. The insert has an annular shape,
The gasket of claim 1. 4. The gasket of claim 1, wherein the insert has a split. 5. The gasket of claim 1, wherein the elastomeric material is attached to each separate portion spaced from each other around the insert. 6. The method of claim 1, wherein the elastomeric material is deposited in a continuous bead around the insert.
Gasket. 7. A body formed of a gasket material, the body having a hole formed therethrough having a diameter, disposed in the hole, nicked, and frictionally retained in the hole. And a insert having an outer diameter when loosened larger than the diameter of the hole. 8. The gasket of claim 7, further comprising retaining means for retaining the insert in the hole. 9. The gasket of claim 8 wherein retaining means for retaining the insert within the hole comprises an elastomeric material that partially surrounds the insert and a portion of the gasket material. 10. The gasket of claim 9, wherein the elastomeric material is attached to each of the spaced apart portions of the insert. 11. The gasket of claim 9, wherein the elastomeric material is applied in a continuous bead around the insert. 12. The insert is 15 RB to 7
The gasket of claim 7 formed of a material having a hardness in the range of 5RB. 13. The insert has an annular shape,
The gasket of claim 7. 14. A crack is formed in the insert,
The gasket of claim 7. 15. A body comprising a gasket material and having a hole formed therethrough, and an insert disposed within the hole and made of a material having a hardness in the range of 15 RB to 75 RB. gasket. 16. The gasket of claim 15, further comprising retaining means for retaining the insert in the hole. 17. The gasket of claim 16, wherein the retaining means for retaining the insert within the hole comprises an elastomeric material that partially surrounds the insert and a portion of the gasket material. 18. The elastomeric material is attached to spaced portions of the insert around the insert,
The gasket according to claim 17, 19. The gasket of claim 17, wherein the elastomeric material is applied in a continuous bead around the insert. 20. The gasket of claim 7, wherein the insert has an annular shape.