Coating implements with material supply – Solid material for rubbing contact or support therefor
Reexamination Certificate
2000-01-26
2001-06-05
Walczak, David J. (Department: 3751)
Coating implements with material supply
Solid material for rubbing contact or support therefor
C401S054000
Reexamination Certificate
active
06241409
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to writing elements, and more particularly, to durable pencils that minimize negative impacts on the environment and, in fact, generate a positive impact on the environment during manufacture and in use and, as such, are “environmentally friendly.”
Conventional pencils that are presently manufactured typically contain a graphite or pigmented lead core inside a wooden sheath. The pencils presently available are unsatisfactory for a number of reasons. For example, the current process for making wooden pencils, which entails laying an extruded graphite insert in a groove longitudinally extending in one half of the wooden sheath, is expensive and requires considerable work and special conditions. The sheath-half containing the graphite insert and the corresponding opposite sheath-half are then coated with an adhesive such as glue and pressed to fit together until dried and set and then undergo a lacquering operation. This process is expensive, requires multiple steps, and is time consuming. For example, lacquering is very labor and time intensive and requires approximately four to twelve passes through a paint line to achieve a desired coating. Consistency in areas such as diameter, length and quality is difficult to achieve and will not only contribute to “down time” during manufacture of wooden pencils but will also translate into the imprinting and decorating market.
As a natural substance, wood is a limited resource and varies widely in composition and properties. Deforestation of woods and rain forests is a significant drawback with wooden pencils. Also, only certain types of wood possess the requisite properties to be used in the manufacture of pencils and those wood varieties are generally expensive. Cedar is most commonly used, although basswood, pine and jelutong are sometimes used in pencil manufacture, especially those pencils manufactured overseas.
Manufacture and use of wooden pencils can also cause health hazards. By way of example, sawdust and other scraps are generated during the pencil manufacturing process, especially during the grooving and shaping of the wooden sheath. As a result, a dust collector is used to collect the sawdust and can cause respiratory problems if not handled correctly. Further, disposal of the scrap product continues to be a problem. In addition, because of the nature of wood, changes in humidity and temperature can cause problems such as warping. Warping, in turn, creates problems in the gluing, shaping and lacquering stages of manufacture and can result in an increase in the amount of scraps generated by as much as one percent or two percent. While in use, pencils having wood casings are also subject to splintering when broken thereby posing a danger, especially to young children.
From the foregoing, it will be appreciated that there exists a need in the art for pencils that do not contribute to the deforestation of the woods and rain forest, and which can be manufactured relatively inexpensively without generating sizable quantities of scraps while minimizing health hazards in manufacture and in use. It will be appreciated that there also exists a need for pencils that are relatively durable, with a heavier weight and that will not easily break.
SUMMARY OF THE INVENTION
The aforesaid problems are solved, in accordance with the present invention, by pencils having an inner marking core surrounded by an outer sheath that comprises reclaimed rubber. Preferably, the reclaimed rubber is in the form of, for example, reground tires or rubber scrap that can be treated to allow for a more compatible bond with surrounding matrix or, preferably, untreated. A base elastomer, such as natural rubber, synthetic isoprene, SBR, butyl, butadiene, EPDM, EPM, chloroprene, nitrile, thiokol®, urethane, silicone, acrylic, fluorocarbon, epichlorohydrin, chlorinated polyethylene, or chlorosulfonated polyethylene can be used in conjunction with the reclaimed rubber. The base elastomer provides a vulcanizate with basic physical and environmentally resistant properties of, at a minimum, elasticity, flexibility and relative impermeability to water and air, while the reclaimed rubber extends the base elastomer to reduce cost while reducing environmentally harmful waste, as perhaps in the form of used tires. In addition to the reclaimed rubber and the base elastomer, one or more fillers, plasticizers, reinforcing resins, antidegradants, processing aids, activators, accelerators, scorch retarders, and vulcanizing agents can be included in the pencils of the present invention, as desired.
Advantageously, the writing instruments of the present invention made from reclaimed rubber eliminate the need for consuming a limited resource, namely trees, while at the same time incorporate a use for used tires which clutter the countryside with unsightly waste, which constitute extremely dangerous fire hazards in their original form and which make poor landfill. The pencils comprising reclaimed rubber under the present invention not only address the above environmental concerns, but also possess a heavier weight and elastomeric surface which give an enhanced “feel” of a premium writing instrument.
Unlike the traditional wooden pencil, the pencils of the present invention comprising reclaimed rubber do not splinter when broken and therefore do not pose a danger to young children. In fact, under most circumstances, the pencils of the present invention are almost impossible to break. Although the rigid graphite filler might break when bent, the rubber case will not break unless cooled to −32° F.(≈−35.6° C.). During manufacture, sizable quantities of scraps are not generated as is the case in the wooden pencil industry. The rubber pencils of the present invention also eliminate major downtime during manufacture, thereby creating a more cost-effective product.
The present invention will be more fully understood upon reading the following detailed description of the preferred embodiment.
REFERENCES:
patent: 141287 (1873-07-01), Orndorff
patent: 1971681 (1934-08-01), Hauton
patent: 3386925 (1968-06-01), Dillhoefer
Erlandson John
Gidley Vernon
Holloway Andrew
Brinks Hofer Gilson & Lione
Walczak David J.
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