US1485214A - Safety razor - Google Patents

Description

H. M. CHANCE Feb. 26, 1924. 1,485,214

SAFETY RAZOR Filed July 27 1922 Patented F.26,1924,

m. con, or rnrnnrnrn, rmmsrnvi a ETY RAZOR.

Application filed July 27,

,have invented certain new and useful Improvements in Safety Razors, whereof the following is a specification.

My invention relates to means for the application to adjustable safety razors of the well known Gillette type, and to safety razors with a single cutting edge, of an improvement in safety razors which I have escribed and claimed in an application for patent Serial No. 486,146, filed July 20 1921, for improvement in safety razors which consists in confining the adjustability of the cutting edge of such razors with in a range between two fixed limits, one of which provides little or no exposure of the cutting edges and the other of which pro vides maximum exposure of the cutting edges consistent with a reasonable degree of safety in use. In carrying out in present invention I also utilize another lnvention which I have described and claimed in an application for patent Serial No. 491,547,

filed August 11, 1921, for improvement in safety razors which consists in flexing the blade to produce longitudinal corrugations in it by means of lines or points contacting with its upper and lower surfaces, said lines or points of contact not being directly op posite to each other whereby pressure to said blade applied through said points or lines of contact produce longitudinal corruations in it, thus holding the blade firmly in position and faddin to the stiffness or. rigidity of its cutting e ges. I do not herein claim either of the above inventions except in combination with the improvement herein disclosed. V

In adjustable safety razors as usually constructed, when the parts are assembled in' position but beforethe blade isfiexed by tightening the clamp, the cutting edges of the blade project beyond lines tangent to the outside faces of the clamp and guard and are about of an inch above the guard, presenting an exposure of the cutting edges muchexceeding that possible for safe use; but when the blade is flexed by progressive tightening of the clamp, the

cutting edges move towards the uard with constantly and nearly the resistance to flexinguntil they reach a position at the limit of movement in which uniform increase in 1922. Serial no. wares.

they project very slightly beyond a line tans gent to the outside aces of the clamp and guard, presenting a very small exposure of the cutting edges of the blade and a high degree-of safety in use. This change in the position of the cutting edges of the blade is accompanied by a regular and gradual in crease inthe resistance to flexing and in the force necessary to efiect flexing from a .po- I sition in which the cutting edge is dangerously exposed to one in whichthere is very small, if any, exposure. After clamping tightly,-with the cutting edges occupying a position with minimum exposure, a very slight reduction in the clamping pressure by a movement of the clam or cover a few thousandths of an inch is sufficient to increase the exposure of the cutting edges to the maximum ex osure consistent with safety, further re uction in the clamping pressure with but slight movement of the clamp or cover increasing this exposure to one inconsistent with safety in use.

My invention consists in constructing-the blade holder and clamp with lines or points of contact adapted to contact with the blade and to produce flexing of the blade with gradual increase in the resistance of the blade to flexing, and with gradual and cor. responding increase in the force necessary to produce flexing, until the. blade is clamped firmly in place, with little or no exposure of the cutting edge, in a position with reference to the guard providing a maximum degree of safety in use, such position being indicated by an abrupt and large increase in the resistance of the blade to further flexing, and the necessit of applying a much greater force to e ect any further change in the position of the cut ting edge, the application of such additional force producing a flattening of curvature, or flexing of the blade adjacent to the cutting edge in a reverse direction from the direction of the initial flexing, such counterflexing increasing the exposure of the cutting edge and thus providing adjustable positions of the cutting edge with reference to its protective guard suitable for close shaving, the movement in this direction being limited to within the range determined as providing a satisfactory degree of safety in use.

Fig. I is an end view of a razor ofthe well known Gillette type showing modification in the construction of the holder and the cutting edges of the blade in position,

with reference to the protective guards giving minimum exposure to the cutting edge consistent with efficiency in use.

Fig. 111 is a similar view showing diagramn'iatically extreme curvature that may e produced in a blade when complete reverse flexing is caused by continued turning of the handle and indicating on an exaggerated scale the relative-position of the cutting edges and protective guards when the cutting edges present a maximum exposure consistent with safety in use.

It will be evident that the range in adjustment is thus confined to the positions illustrated by Figs. II and III and that any desired intermediate adjustment may -be made by turning the handle.

The operation of this device is dependent upon the change in leverage produced by applying the flexing force to different parts of the blade.

In the drawings 1 is the razor blade of thin flexible type with two cutting edges, 2 is a cap or clamp with threaded pin 3 adapted to engage with athreaded socket in the handle, 5 is the holder carrying guards 6, 6, of'either the bar or comb type, on each side, and having two grooves or depressions 7, 7, extending longitudinally.

and parallel to the guards. The upper surface of the holder 5 is curved with a curvature preferably slightly more convex than the under side of the clamp 2. One side of the depressions 7, 7, preferably form edges or corners 8, 8, with the top surface of the holder 5 or with the guards 6, 6, which edges may be-slightly rounded to reduce the bending stress on the blade.

The drawing Fig. I shows the holder, blade, clamp and handle assembled loosel the blade not bein clamped for use, in which position the b ade rests upon the center 9 of the holder 5 and is prevented from tiltin by contact with the edges 10, 10 of the. 0 amp 2. Upon turning the handle 4 in a direction to tighten the clam 2, downward pressure is exerted upon t e blade 1 along the lines of contact 10, 10, and upward pressure is exerted upon it along its line of contact 9 with the holder 5.- Under these conditions, i. e., the application of flexing pressure along the center line of the blade far from the fulcrums 10, 10, the blade yields easily to slight pressure, and the force necessary to apply in turning the'liandle 4 is relatively small but increases steadily as flexing force at 10, 10, are equal to the width of'the depressions 7 7, as compared with the single span, from 10 to 10 flexed in the preliminary flexing by application of a force at 9, and as these smaller spans are each about one-fourth the length of the larger span the force required to reverse the flexure in the blade 1, or to produce equal angular flexure in the blade by application of the flexing force at 10, 10, may therefore theoretically approximate to 16 times that necessary to effect the initial flexing of the blade. This abrupt chan e in the force re quired to turn the han le 4 is suflicient notice to the user that the blade is firmly clamped and ready for use, and is in a position giving the minimum exposure of the cutting edges consistent with efliciency in use. The cutting edges may then be adjusted to any greater degree of exposure by turning the handle 4 thus flattening or reversing the curvature of the blade at 10, and increasing the exposure of the blade to one better adapted to close shaving.

It will be observed that the drawing Fig. II shows a space about one-eighth of an inch wide between the top of the blade 1 and the under side of the clamp 2 along the central portion of the clamp op osite the central region of the holder 5 designated by the numeral 9. This space has been exaggerated in order to make the drawing more legible. The holder 5 preferably should be made with its top surface slightly more convex than shownso that the distance between the top of the blade 1 and the under side of the central part of the clamp 2 will be equal to the further proposed downward movement of the clamp 2, this movement providin for and limiting the adjustable range 0 the position of the cutting edges of the blade, so that when the blade thus been depressed into the depression 7, 7, by the downward movement of edges 10, 10, of the clamp 2, a suflicient distance to produce the maximum flattening or reversal of flexure required to give maximum exposure to the cutting edges consistent with safet in use, further movement and flexing wil be prevented by the under surface of the clamp 2 coming into contact at central region with the top of the blade 1, whichin turn is in I contact with the holder 5 at the region designated by 9. When the razor blade is of a thickness not readily flexed, the increase in pressure required to efiect adjustable counterflexing of the blade after the blade has been flexed to the position shown by Fig. II may, if desired, be used to limit the range of adjustment to. prevent over expo sure of the cutting edges, without reference to the contact of the blade with the under side of the clamp 2. This can readily be done by making the width of the depressions 7, 7, such that the unsupported span of the blade is so small that excessive counterflexure cannot be produced by any force that can be applied by the means provided for that purpose, or, that such force, if applied, will be sufficient to break the blade. I find in practice that a very slight flattening of the curvature at 10, such as is diificult to detect with the naked eyeconstitutes suificient reversal in the flexing to produce an appreciable greater exposure of the cutting edge. Fig. III has been drawn with exaggerated curvature of the blade to better illustrate an extreme case of reverse flexing of a blade, such as is only possible with an extremely thin blade made of especially tough and flexible metal, without danger of breaking or deforming the blade. Extreme counterflexing tends to cause the central part of the blade to rise in an are away from the top of the-holder 5, towards the under side of the clamp 2, but in many cases friction at the points of contact 8 and 10 is sufiicient to restrain. this movement so that the under surface of the blade remains in contact with 118 holder 5 at or near its center designated It will be understood that my above described invention may be used in connection with the construction and operation of safety razors of types differing materially from the Gillette type illustrated by the drawings, and that this type may be modifled without departure from the spirit of my invention, e. g., the lines of contact 8, 8, 10, 10, and 7, 7 are not necessarily continuous lines, but may be broken at intervals or may consist of a number of points making contact with the blade at any desired distances apart.

edges being however limited by the necessity I do not confine myself to the particular dimensions or shapes of the different parts shown by the drawings as these may be widely varied without departure from the essential elements of my invention. The groove or depression 7, 7, may, if desired, be made of any desired width, their inner of preserving intact a small part of the central part of the holder 5, the position of which is indicated by the numeral 9.

The terms counter-flex, counter-flexing and counter-flexure in this specification and in the claims hereof are intended to mean and to include the effects produced by the application of a force that tends to reverse the curvature of the blade produced by preliminary flexing, whether such force actually roduces a reversal of curvature or merely attens in greater or lesser degreev the curvature produced by said preliminary flexing, hence these terms are used to mean and include either flattening or reversal of the curvature produced by preliminary flexing.

Having described my invention, I claim:

1. A safety razor including a holder having a guard, a flexible razor blade, a clamp securing the blade and the holder together, means for preliminarily flexing said blade longitudinally, and vmeans permitting counter-flexing of said blade, said first mentioned means including a depending edge of said clamp en aging the blade in a sub- 'stantial line, sai second mentioned means including a longitudinal groove in said holder directly under the depending edge of the clamp.

2. A safety razor including a holder having a guard, a flexible razor blade, a clamp securing blade and bolder together, means for preliminarily flexing said blade longitudinally, means for counter-flexing said blade, said last named means engagin said blade in a substantial line, longitudina 'ly of the same.

In' witness whereof I have hereunto set me my hand this 25th day of July, 1922.

HENRY M. CHANCE.

\Vitnesses:

CARL K. SGHULZE, FRANK H. Mums.

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