Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Patent
1988-06-15
1992-07-28
Lesmes, George F.
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
428224, 428289, 428367, 428377, 428408, 57230, 57231, 57232, 277230, 277DIG6, 87 1, 87 6, 87 9, D04C 100, D06P 700
Patent
active
051340305
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to packing material and packing preferably suitable to gland packing or the like for use in a shaft seal part of a hydraulic machine.
2. Prior Art
A variety of gland packings in which flexible graphite is used as a base material have been hitherto known for use in a shaft seal part or the like portion of a hydraulic machine, for example.
Gland packings of this sort are manufactured by various techniques, such as laminating, die molding, chip molding, and ribbon packing. However, these techniques require that the graphite material must be previously molded into a ring shape conforming to the diametral size of a shaft with which such packing is to be used; as such, the packing cannot be used with any shaft having a different diameter. Therefore, such packing lacks versatility in use. Another, difficulty with such packing is that since flexible graphite is of low tensile strength and brittle in itself, once the packing is mounted in position it is extremely difficult to remove same when replacement is required, which means less usability.
Further, the aforesaid manufacturing techniques individually have drawbacks of their own. The laminating technique involves the problem of poor yield, which leads to higher cost. Where the die molding or chip molding technique is employed, dies or metal molds are required, which means higher cost, and the packing produced is less versatile. The ribbon packing technique does not provide good workability. These difficulties may be overcome by forming the flexible graphite into a cord-like structure so that it may be used by being cut to a specified length conforming to the diameter of the shaft, as is the case with such other type of packing as fiber braided or knitted; but the trouble is that flexible graphite cannot be braided or knitted because, as pointed out above, it is in itself of low tensile strength and so brittle that its compressibility and allowable limit of twist are both extremely low. Therefore, it has hitherto been considered impossible to use such packing in such a way as is usual with the aforesaid fiber braided or knitted type of packing, that is, in such a way that the braided or knitted packing is cut to a length according to the diametral size of the shaft with which it is to be used, the so cut packing being then wound about the outer periphery of the shaft.
SUMMARY OF THE INVENTION
In order to overcome the aforesaid difficulties it is hence a primary object of this invention to present a packing material which can be either twisted or braided, and a twisted or braided cord-like packing by using the same packing material, by using a flexible graphite sheet cut to a width of less than 5 mm in order to advantageously utilize a characteristic feature of flexible graphite in sheet form in particular that if such sheet is cut to a width of less than 5 mm, both its compressibility and its allowable limit of twist are significantly increased as shown in FIG. 11 and FIG. 12, and by covering the flexible graphite sheet with a fiber material in order to attain the synergistic action of the fiber material and flexible graphite sheet.
It is a second object of this invention to present a packing material which can be either twisted or braided and is small in elongation and high in strength, and a twisted or braided cord-like packing by using the same packing material, by using a flexible graphite sheet cut to a width of less than 5 mm, laminating this flexible graphite sheet with at least one of reinforcing fiber material or foil material, and covering this surface with the fiber material to attain the synergistic action of the fiber material and flexible graphite sheet, and the reinforcing fiber or foil material.
It is a third object of this invention to present a packing material which can be either twisted or braided, and a twisted or braided cord-like packing by using the same packing material, by forming a bar mainly composed of flexible graphite particles and containing at least o
REFERENCES:
patent: 4559862 (1985-12-01), Case et al.
patent: 4705722 (1987-11-01), Ueda et al.
Shiomi Tomikazu
Ueda Takahisa
Brown Christopher
Lesmes George F.
Nippon Pillar Packing Co. Ltd.
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