1. Field of the Invention
This invention pertains to razor type cutting devices generally, and more specifically to a line trimmer having a razor integrally and permanently molded into a safely transportable housing.
2. Description of the Related Art
The cutlery art is an old and highly refined field, having origins that date to man's earliest tools. Hammered rock edges, sharp fragments of bone or tooth, tusks and other easily derived devices provided humans with the earliest cutlery. These naturally occurring or minimally refined knife blades were replaced with copper and iron blades as people began to develop the art of metal working. Metal blades offered distinct advantages, delivering thinner, sharper and often more durable cutting edges.
As with many other inventions, metal blades brought new challenges to the world. These cutting edges were so sharp that they were able to almost effortlessly cut human flesh. The problem was compounded with the development of razor blade technology at the start of the twentieth century, when paper-thin metal was formed into cutting edges. As any office worker can attest to, paper itself is capable of cutting flesh when mishandled. These new razor blades were so sharp that simple contact with the edge would break through one's skin.
Nevertheless, the world had many applications for these newer and sharper blades. Among the earlier applications are hair trimmers, which often included combs clamped about razor blades. These trimmers were designed to be drawn through a person's hair. As long as the blade remains sharp, the hair is severed upon contact with the blade. Exemplary of these are U.S. Pat. No. 1,486,672 to Mazzoni; U.S. Pat. No. 1,976,290 to Motley; U.S. Pat. No. 2,972,187 to Gore; and U.S. Pat. No. 4,441,252 to Caves. Each of these patents disclose hair trimmers having a blade clamped between removable, combed housing pieces, and having handles extending therefrom. U.S. Pat. No. 2,641,055 to Mansfield and U.S. Pat. No. 4,663,841 to Custer each disclose similar hair trimmers, without the handle. Other applications include fuzz removers, as shown in U.S. Pat. No. 4,769,913 to Kuramochi; finger nail trimmers as shown in U.S. Pat. No. 2,544,479 to Zengel; fishing line trimmers such as U.S. Pat. No. 5,182,874 to Powell and U.S. Pat. No. 5,685,037 to Fitzner et al; and even windshield wiper blade sharpening devices such as U.S. Pat. No. 5,359,776 to Glazar. Each of these foregoing designs provide a razor edge while, to varying degree, protecting a person from injury.
Other attempts were made to protect a person from unintentional injury, while still allowing these blades to be used for diverse purposes. Logan illustrates this in his combination tool disclosed in U.S. Pat. No. 1,667,462. The Logan tool includes a folding blade and holder, which allows the blade to be exposed during use and otherwise safely stored. In addition, Logan identifies the possible utility of the new blades for applications as diverse as thread or twine cutting, shaving, cigar cutting, seam ripping, pencil sharpening, furrier and leather cutting, newspaper clipping, and even corn cutting.
In parallel to these diverse applications has been the further development of the razor blade for the original use of shaving hair from the skin. As with other applications, skin cuts are undesirable. Various attempts have been made to allow the blade to still operate effectively while reducing the chances of damaging skin. Examples are found in U.S. Pat. No. 3,675,325 and U.S. Pat. No. 3,774,294 to Michelson and U.S. Pat. No. 4,211,006 to Halaby et al, which each provide small rounded protrusions extending from the blade edge to assist in guiding the blade over skin without cutting in.
In addition to protection during use, there is a need for safe blade disposal. Since razor blades are designed for use in a wet, soapy environment, and yet are still expected to remain sharp for extended periods, the materials have been designed to be highly resistant to environmental degradation. Furthermore, they are designed for nearly effortless cutting. How then does one dispose of used blades, when they do not degrade quickly and can cut through large quantities of trash or protective wrapping to once again expose persons to injury?
In spite of the many years razor blades have been available, there has not yet been a razor cutter that could truly offer the full benefit of the sharp blade and small size while still protecting a person from accidental injury and enabling safe disposal. To the contrary, the vast majority of these devices were unsuccessful specifically because of the damage they would cause to an unwary user either during use or after disposal. For example, hair trimmers include provisions for removing the razor blade from trimmer. Unfortunately, these trimmers occasionally loosen during use, exposing the person to the blade and potential injury. In many cases then, a compromise is made between the size of the guard and the ability for the blade to perform an intended function.
Nowhere is this more obvious than with razors designed for shaving, such as in the Michelson patents referenced hereinabove, where guards are only a few thousandths of an inch thick. In fact, and in spite of these guards, because of the risk of injury and difficult disposal, a large market has developed for electric razors.
The same is true, of course, for each of the other applications, where alternative devices have been used to avoid the risk of injury from the razor. In sewing, scissors are vastly preferred and steel seam rippers have also gained wide-spread use, in spite of the improved cutting ability and lower cost of the razor. Noteworthy is the fact that a razor often costs significantly less than a single scissor resharpening, and the razor provides improved cutting ability. In fishing, nail clippers are a common part of the tackle instead of razor blades. This is striking when one contemplates the frequent injuries that result from fish hooks. Fishermen are more concerned about razors than fish hooks.
As is apparent, the razor has not established dominance proportional to it's effectiveness among cutlery. Primary among the factors contributing to this lack of success is the enormous risk of injury during use, when changing blades, and after disposal.