Winding – tensioning – or guiding – Reeling device – Fishing rod reel
Reexamination Certificate
2002-07-11
2003-11-04
Marcelo, Emmanuel M. (Department: 3654)
Winding, tensioning, or guiding
Reeling device
Fishing rod reel
Reexamination Certificate
active
06641069
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a drag washer used for a drag mechanism of a fishing reel and to a fishing reel using the same.
BACKGROUND
In general, a drag mechanism of a fishing reel is given a setting of a braking force so that when a tensile force in excess of a predetermined value is exerted on a fishing line, the drag mechanism is made to slip to allow the fishing line to be reeled out in response to pull of hooked fish, so as to prevent the fishing line from being break. The drag washers that are generally used as braking friction plates in the drag mechanism include, for example, asbestos-phenol-resin molded material, flammable woven fabric greased or impregnated with oil grease, and carbon-fiber woven fabric impregnated with resin and cured.
These drag washers have the problems, however, that the friction resistance is subject to change under environmental changes, such as change in friction resistance caused by entrained seawater, change in friction resistance caused by frictional heat, and change in friction resistance resulting from durability in thickness direction against tightening force.
To eliminate these drawbacks of the conventional drag washers, graphite drag washers have been developed recently. The graphite drag washers have the advantages of being hardly subject to change in friction resistance under environmental changes and providing the excellent drag force for an extended time period.
However, in the producing process of the graphite drag washers, it is required that the drag washers are cut out into any desired size from some degree of size of graphite block by machining.
This causes increased costs in manufacturing the fishing reel using the graphite drag washers, leading to the disadvantage that the use of the graphite drag washers are limited to some high-grade goods. In addition, when used for general fishing, the graphite drag washers can produce excellent drag force and provide comfortable operation for an extended time period.
However, when the graphite drag washers are used to a large-sized fishing reel for marlin and large-sized fish, whose drag mechanism is given a setting of braking force of a relatively large value, there is the possibility that when a large braking force is exerted on the drag washers, the graphite drag washers may be cracked due to its own fragility that is one of the disadvantages of the graphite material.
It is the object of the present invention to provide a drag washer for a fishing reel that can provide a drag force equal to or more than that of the graphite drag washer for an extended time period, can be produced at reduced costs and without difficulty and is applicable to a variety of fishing reels for a variety of fish ranging from small-sized fish to large-sized fish.
DISCLOSURE OF THE INVENTION
The inventors have focused attention on an expanded graphite sheet having an excellent sliding property equivalent to that of the graphite material and have pursued their studies thereon with their whole heart. The conventional expanded graphite sheet has an excellent sliding property, but on the other hand, it lacks some required properties for the drag washer of fishing reel, such as strength and hardness. Due to this, it was practically infeasible to use the expanded graphite sheet for the drag washer of fishing reel.
The inventors have found that enhanced hardness can be produced by adding heat-resistant reinforcing fiber, such as fiber pulp, used as reinforcing material to the expanded graphite and then binding them by use of a heat-resistant binder such as thermosetting resin. Further, they have found the proportion in which three components, namely, expanded graphite, heat-resistant reinforcing fiber and heat-resistant binder, are mixed to produce a sheet having the required strength and sliding properties for the drag washer of fishing reel, then bringing the invention to completion.
A fishing reel's drag washer of the present invention is formed from a sheet comprising a mixture of expanded graphite and heat-resistant reinforcing fiber as is solidified by a heat-resistant binder. It is preferable that the sheet has a thickness of 0.7-1.2 mm and a bulk density of 0.8-1.2 g/cm
3
. Also, the sheet is produced in such a process that 40-80 mass % of expanded graphite, 5-25 mass % of heat-resistant reinforcing fiber and 10-40 mass % of heat-resistant binder are mixed, followed by heat-treatment to cure the heat-resistant binder.
The expanded graphite used for the fishing reel's drag washer of the present invention is produced as follows. For example, flake graphite is subjected to acid treatment by using sulfuric acid and oxidizing agent to thereby produce acidized graphite, first, and then heated rapidly to approximately 1,000° C. so as to be expanded 100-300 times. Thereafter, the expanded graphite is ground in powdery form by using a granulator. Then, after the expanded graphite is formed into a felt form or a sheet form having a bulk density of 0.05-1.5 g/cm
3
, the expanded graphite of felt form or sheet form is further ground in powdery form by using any proper high-speed mill type of grinder. Preferably, the powders of either of the felt and sheet have a bulk density of 0.05-1.5 g/cm
3
and a mean particle size of 150-250 &mgr;m. The expanded graphite ground into powdery form by the granulating method is easily delaminated, so that it is uniformly mixed with the heat-resistant reinforcing material and the heat-resistant binder with ease. The expanded graphite obtained when the felt of a bulk density of less than 0.05 g/cm
3
is ground becomes so bulky that it is hard to deal with. On the other hand, the expanded graphite obtained when the sheet of a bulk density of more than 1.5 g/cm
3
is ground is formed in the granular form, so that the characteristics of the expanded graphite itself are impaired.
Preferably, the heat-resistant reinforcing fiber is in a pulp form and have a large specific surface area, in terms of heat resistance as well as reinforcement of the expanded graphite powder. The fibers that may be used include inorganic fiber, organic fiber and metal fiber. Practically, the organic fiber that can take a relatively large specific surface area is preferably used. To be more specific, aramid fiber pulps of para-series or meta-series may be used. Also, infusible cellulose pulps may be used, though there is a limit to use.
The aramid fiber pulp of para-series used as the heat-resistant reinforcing fiber mentioned above is preferably 3.0 m
2
/g or more in specific surface area, or further preferably 5-20 m
2
/g. The fiber length of 0.9-2.0 mm affords good dispersibility and high filler retention of 50-70%. The specific surface area of less than 3.0 m
2
/g is not good enough to provide the reinforcing effect of the expanded graphite and as a result, the strength of the sheet obtained is reduced.
Thermosetting resins are preferably used as the heat-resistant binder for bonding the expanded graphite and the heat-resistant reinforcing fiber. Particularly preferable are phenol resin, polyester resin, and epoxy resin. Among others, fine-grained phenol resin having a mean molecular weight of not less than 5,000 and a mean particle size of not more than 20 &mgr;m which affords excellent sliding properties is of preferable. This thermosetting resin is easily soluble in solvent and is able to be uniformly dispersed in between the expanded graphite powders and the fiber pulps.
For the purpose of enhancing the sliding properties, 4-5 mass % of molybdenum disulfide powder may be added as sliding material, if required. This enables the control of the sliding properties of the drag washer.
The sheet used for the fishing reel's drag washer of the present invention is produced by the respective materials cited above being mixed and then solidified. The respective materials are preferably mixed in a mixing proportion of 40-80 mass %, or preferably 50-70 mass %, of expanded graphite, 5-25 mass %, or preferably 10-20 mass %, of heat-resistant reinforcing fiber and 10-40 mass %, or prefe
Hasegawa Hiroshi
Katayama Hitoshi
Kondo Teruhisa
Kusuyama Toshiki
Marcelo Emmanuel M.
Shimano Inc
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