This invention relates generally to devices for shaving portions of the human body, and more specifically, relates to a shaving assembly, which while generally useful in body shaving applications, is especially applicable to shaving which is effected as an incident of surgical procedures.
As one aspect of surgical treatment of portions of the human body, as for example, as an incident of treatment of trauma or disease, the physician or other treating personnel may be required to eliminate surface hair which could interfere with the surgical procedure or with healing of the impaired bodily portion. Removal of such surface hair has customarily been effected by use of one of two procedures, i.e. by razor preparation, or by use of a depilatory. Since certain aesthetic and physiologically objectionable characteristics are inherent in use of depilatories, the preferred and most widely used preparatory technique, indeed involves use of shaving via a razor assembly.
In recent years it has come to be increasingly recognized, however, that razor preparation can contribute to post-operative complications by virtue of injury to the epidermis which is often incident to such technique. Reference may be had in this connection, for example, to the article by Richard Seropian, M.D., and Benedict M. Reynolds, M.D., entitled "Wound Infections After Pre-operative Depilatory versus Razor Preparation", appearing in the American Journal of Surgery, Volume 121 (March, 1971). The sheer economic impact of such shaving-induced infection, e.g. in resulting increased length of hospital stay, is also very significant, and is discussed in an article appearing in the "Medical News" section of the Journal of the American Medical Association, pgs 9 f.f., Jan. 2, 1978, Vol. 239, No. 1.
Analysis of prior art shaving techniques will establish that the shaving of hair has conventionally involved the concept of trapping the hair between a relatively sharp blade edge and the skin adjacent to the hair follicle. Before the advent of the safety razor, in addition to the trapping action, the blade edge was moved so as to provide a slicing type of action. Even with extreme care, the epidermal layer of the skin was broached extensively. The conventional safety razor design was such that a slicing type of action was not practical, and the cutting action resembled more the action of a hoe cutting weeds in a garden. Just as the hoe damages the earth adjacent to the weeds in the garden, so does the safety razor blade damage the epidermis next to the follicle of the hair.
The above points are illustrated in FIG. 7 herein, which is a schematic enlarged view of the operative portions of a typical prior art safety razor, illustrating the manner in which these portions function during the shaving operation. This view, which is thus in section and simplified, shows a razor blade 2 sandwiched between a blade seat 4 and a blade cap 6. The guide bar 8 typically present in the shaving assembly 3 is also shown, and it may be assumed that during shaving the assembly 3 is drawn in the direction of arrow 5.
Particularly to be noted in FIG. 7 is that the protruding portion 9 of the blade 2, actually is designed so that the terminal cutting edge 11 extends a distance D' beyond a reference plane 13 which is defined by the outer surface 15 of cap 6 and the cooperating surface 17 of guide bar 8 which resides across from surface 15 in the direction of cutting edge 11. Plane 13 approximately coincides with the theoretical surface of skin 19, and it will be seen that the cutting edge 11 thus extends by the said distance D' beyond the theoretical skin surface, but extends by a distance D, which is greater than D', beneath the true skin line--by virtue of the deformation of the skin (such as at 19a) which occurs during shaving.
The effect of this protrusion beyond the theoretical and actual skin lines is that the blade edge 11, at the least rubs along the skin, and more generally shaves into the epidermis. In the case where the epidermis is thin, as in most parts of the body other than the pads of the hands and feet and the face of shaving males, the epidermis is severely broached, with consequent rawness, bleeding and opportunity for infection.
In general, therefore, the degree and extent of damage to the epidermis is a function of the protrusion depth D' of the blade cutting edge beyond the guide plane established by the razor guide bar 8 and the razor cap 6, the angle at which the blade approaches the skin (the "angle of attack"), and of other factors including the sharpness of the blade, the softness of the hair, the toughness of the epidermis, and the degree and direction of turn on the edge of the blade.
While the above comments have been directed particularly at the undesirable aspects of prior art razors as same are utilized in surgical shaving, it will of course, also be evident that the remarks are equally applicable to any shaving operation, i.e. including those conducted for cosmetic or other reasons.
Pursuant to the foregoing, it may be regarded as an object of the present invention, to provide a shaving assembly which enables removal of excess body hair as an incident to surgical or other needs, without damaging the epidermis, thereby minimizing the risk of infection incident to such shaving.
It is a further object of the present invention, to provide a shaving assembly as aforesaid, which enables a substantial reduction in the cost of surgical preparation supplies, by reducing or completely obviating the need for lather, sponge, and disinfectant use.
It is a still further object of the invention, to provide a shaving assembly as aforesaid, which enables a substantial reduction in the time required to perform preparatory shaving operations, by obviating any requirement for softening of the hair by lathering or otherwise, by enabling ready visability of the hair being shaven, and by eliminating a requirement for rinsing or otherwise removing the shaved hair from the razor's cutting edge.