PATENT SPECIFICATION

Convention Date (United States): Jan. 19, 1932. Application Date (in United Kingdom): April 26, 1932. No. 12,004/32. Complete Accepted: Oct. 26, 1933.

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COMPLETE SPECIFICATION. Improvement in Safety Razors

400,621

We, Gillette Safety Razor Company, a corporation of the State of Delaware, United States of America, of No. 15, West First Street, Boston, Massachusetts, United States of America, do hereby declare the nature of this invention and in what manner the same is to be performed, to be particularly described and ascertained in and by the following statement:—

The present invention relates to improvements in or relating to safety razors in which a flexible blade is clamped and flexed between co-operating cap and guard members by which it is positioned and supported and its cutting edge is given the rigidity necessary to make it operative for shaving.

In removing a blade for purposes of cleaning or substitution, it is desirable to open the cap and guard members quickly and completely so that the blade may be reached and withdrawn without obstruction and with a minimum of danger of cutting the fingers. It is equally important to expose fully the blade-receiving face of that member of the razor upon which the used or new blade is replaced or placed preparatory to clamping the blade for shaving so that the user may conveniently locate the blade upon studs or other positioning means of a steady pin character.

Hitherto safety razor blade holders of the kind referred to in general have been open to the objection that the holder is so constructed as to disassemble into a number of separate parts, whose manipulation for cleaning or blade changing, and re-assemblage afterwards, involves inconvenience, and whose provision within the limitations of economical manufacturing methods for determining the relative position of the cap and guard members lacks that positive accuracy which is desirable to make the razor an instrument of that precision and having that power of adjustment which shall be conducive to refined shaving.

Now, an object of the present invention is to obviate the foregoing disadvantage by providing a safety razor blade holder in which the handle and the clamping (cap and guard) components remain connected together when the holder is opened for cleaning and/or the insertion or replacement of a blade.

With this object in view and taking into consideration that it is required that the stored spring energy of the flexed blade shall not produce any movement of the cap sections so as to disturb the setting of the razor selected by the user, the present invention provides a safety razor blade holder adapted to flex a flexible razor blade and maintain it in the desired condition of flexure for shaving, in which the holder components are maintained as a unit assemblage when the holder is in the open position by the provision of clamping sections which are mounted to fold towards or away from their companion clamping member and towards or from each other for clamping the blade, or exposing the blade (or its seating) respectively, and which are controlled in such movement by positive co-operating non-reversible connecting means between such sections and actuating means therefor.

In another aspect, the present invention provides a holder adapted to flex a double-edge flexible blade and maintain it in the desired condition of flexure for shaving, in which the holder components are maintained as a unit assemblage when the holder is in the open position by the provision of cap sections which are connected to the guard so as to fold towards or away therefrom and towards or from each other for clamping the blade, or exposing the blade (or its seating) respectively, and which are so constructed and arranged as to be capable during their folding movement towards each other of flexing the blade and to leave both cutting edges of the flexed blade exposed for shaving.

Conveniently and advantageously such non-reversible connecting mechanism consists of a worm arranged to mesh directly with portions of both clamping or cap sections, for example, each clamping or cap section may be formed with a portion which constitutes in effect a worm gear and these portions may be oppositely arranged so that an interposed worm may mesh directly with both of them, the worm gearing being made self-locking or irreversible by making the thread angle equal to or smaller than the angle of repose or angle of friction, this angle varying widely with the nature of the particular materials employed and with the presence or absence of unguents, but it will be understood that the choice of the angle of pitch of a well made fitting worm gear presents no difficulty to the skilled designer. Under such conditions a positive operating connection is established and, moreover, one which is non-reversible in its action ; that is to say, the clamping or cap sections are positively locked in all positions in normal use. Any convenient means may be employed for rotating the worm, but as in the embodiment hereinafter described, we prefer to incorporate it as a part of the handle of the razor, extending its hab to form an actuating sleeve. This is a particularly convenient construction for the user and from the mechanical standpoint has all the advantages of direct and simple action with little or no lost motion.

The desired results of the present invention are well secured by employing a cap member which comprises co-operating sections separately pivoted to the guard member along opposite edges thereof and arranged to swing from a superposed blade-clamping position to an inoperative position in which the blade-receiving face of the guard member is entirely exposed.

Attempts made heretofore to utilize such sectional cap members in the construction of safety razors have lacked the provision of satisfactory mechanism for controlling the position of such sectional cap members and moving them positively and quickly from blade-clamping to blade releasing position and vice versa.

A novel constructional feature of importance of the present invention consists in a rotatable actuating member, which conveniently and advantageously may be a part of the handle construction, and positive co-operating connecting means between such rotatable actuating member and the folding clamping or cap sections whereby to cause such sections to be moved simultaneously and equally in opposite directions and positively to control them in all positions.

As a further feature of the present invention, each cap section may be formed with or may be connected to a spindle which is so located that a portion thereof may supply guard teeth for the razor. The guard teeth swing with the spindle and are properly positioned with respect to the corresponding shaving edge of the blade when the latter is clamped in shaving position. These spindles also offer convenient means in which to form the worm teeth which mesh with the worm for swinging cap sections in the manner already described.

In order that the present invention may be the more clearly understood reference is hereinafter made to the constructional example thereunder which is illustrated in the accompanying drawings, in which:—

Fig. 1 is a view in perspective of the razor in condition for shaving.

Fig. 2 is a view in end elevation showing the razor in the same condition.

Fig. 3 is a view in end elevation showing the razor in its open or blade-receiving or blade-withdrawing position.

Fig. 4 is a plan view of the razor in open condition, portions of the blade being broken away.

Fig. 5 is a fragmentary view showing the guard in longitudinal section.

Fig. 6 is a cross-sectional view of the line 6—6 of Fig. 5, and

Fig. 7 is a cross-sectional view of the razor in the condition shown in Fig. 3.

The guard member 10 of the razor herein shown is provided with a blade receiving face which supports the blade for transverse flexure, being provided with two parallel longitudinally extending shoulders over which the flexible blade is flexed by the cap. Projecting from the blade-receiving face of the guard is a pair of blade-locating studs 12 herein shown as being of diamond shaped contour. At each of its corners the guard 10 is provided with a transversely and outwardly extending bearing arm 14 and extending between each pair of these arms and along the longitudinal side of the guard is a rotatable spindle 16. Each spindle is journalled upon a pair of pivot pins 18 projecting through the bearing arms 14 of the guard. Each spindle 16 is provided midway between its ends with worm teeth 20 and the outer portion of the periphery of each spindle is notched to provide guard teeth 22 of the character commonly employed in safety razors of this general type.

The cap member of the razor herein shown comprises two cap sections 24 symmetrically shaped and together providing a concave or equivalently shaped under face which co-operates with the blade receiving face of the guard to flex the blade and maintain it in a condition of pronounced transverse curvature. Each cap section 24 is provided in its face with spaced recesses 26 which register with each other when the sections are closed and provide clearance for the studs 12 of the guard. Each cap section 24 is provided with an arm 28 at each end by which it is connected to rotate with one of the spindles 16. Preferably the cap and spindle are formed integrally, but in any case the cap section 24 and spindle 16 will form a rigid assembly, the body of the cap section being spaced from the spindle by its arms 28, thus providing a longitudinally elongated opening for the passage of the edge of the blade, as will presently be explained. As herein shown the arms 28 of the cap section 24 embrace the ends of the spindle 16, being interposed between it and the bearing arms 14 of the guard.

In Fig. 4 is shown one form of blade 30 suitable for use in the razor of our invention. This is sharpened upon its opposite edges and provided with a recess at each corner affording clearance for the arms 28 of the cap section. It is provided with a blade locating aperture, comprising an elongated slot having spaced enlargements which fit upon the blade locating studs 12 of the guard. The blade is normally flat as shown in Figs. 3 and 7 and is adapted to be transversely flexed and maintained in such position as shown in Figs. 2 and 6.

In the razor herein shown a rotatable element preferably forming a part of the handle is employed to move the cap sections from clamping to blade-receiving position and vice versa, and to positively control their position at all times. This mechanism will now be described. The handle comprises a stationary stem or spindle 32 which is riveted or other wise rigidly connected to the guard 10. At its outer end the stem 32 is enlarged to form a knurled barrel 34. Journalled upon the spindle 32 is a knurled actuating sleeve 36 and this is provided at its upper end with a worm 38 of relatively large diameter which meshes directly with the worm teeth 20 of the spaced spindles 16. It will be noted that the worm 38 is interposed directly between the two spindles 16 and that in effect its hub is extended to form the sleeve 36 by which the worm may be conveniently turned. In order that both spindles 16 shall be firmly and positively locked by their connection with the worm against reverse operation by the elasticity of the flexed blade, due regard is to be had to the angle of pitch of the worm gear as hereinbefore described. This is important because the clamping action of the cap sections is effected against the tension of the blade 30. Accordingly, if the operating connection were not irreversible, the tension of the blade would tend to swing the cap sections and loosen their engagement with the blade. The movements imparted to the spindles 16 by the worm 38 are equal in extent, but opposite in direction, and simultaneous in timing. A pitch angle of the worm gear of 3° as shown in the accompanying drawing is found to work well. By “irreversible” it will be understood that the worm gear can only be operated by rotating the worm as the driver and not by rotating the worm gear as the driver.

In using the illustrated razor the actuating sleeve 36 will first be turned by the operator to rotate the spindle 16 and swing the cap sections 24 into their open or blade-receiving position as shown in Fig. 7. In this position the blade receiving face of the guard 10 is completely exposed and the user may conveniently place the blade 30 thereon without obstruction or interference of any kind. The blade is accurately located on the guard by the blade-locating studs 12 as already explained. The user then turns the actuating sleeve 36 rotating the worm 38 in the direction necessary to rotate the spindles 16 and swing the cap sections 24 simultaneously inwardly towards the guard 10 and towards each other from their positions shown in Figs. 3 and 7 to their positions shown in Figs. 2 and 6. In this movement the outer or blade engaging edges of the cap sections are carried over the sharpened edges of the blade without contacting therewith or tending in any way to dull them. As the inward swinging movement of the cap section continues the blade is engaged along lines adjacent to but within its cutting edges and it is flexed over the fulcrum shoulders of the guard, its edges being disposed in the proper shaving relation to the guard teeth 22 formed in the spindle. The clamping pressure of the cap section and consequently the degree of exposure of the edges of the blade may be regulated by tightening or loosening the actuating sleeve 36. When the actuating sleeve 36 is turned to the limit of its movement the cap sections 24 are drawn down to their extreme clamping position and maximum curvature is imparted to the blade, a condition which corresponds to minimum edge exposure.

On the other hand by slacking off the operating sleeve 36 slightly, the clamping pressure of the cap sections 24 may be relieved and the blade permitted to straighten, thus increasing its edge exposure. It should be observed that in all positions of adjustment the cap sections are positively locked and prevented from slipping or from being displaced in either direction, on account of their connection with the actuating sleeve 36, through the irreversible worm gear.

It will be observed also that the guard pieces 22 on the spindles are carried into an inoperative position when the spindles are rocked to open the cap sections 24, but when the spindles are rocked in the opposite direction to position the cap sections in blade clamping position and the razor is thus made ready for use, the portions of the spindles having the guard teeth are brought back to operative position where the guard teeth are effective in the shaving operation.

Having now particularly described and ascertained the nature of our said invention and in what manner the same is to be performed, we declare that what we claim is:—

1. A safety razor blade holder adapted to flex a flexible razor blade and maintain it in the desired condition of flexure for shaving, in which the holder components are maintained as a unit assemblage when the holder is in the open position by the provision of clamping sections which are mounted to fold towards or away from their companion clamping member and towards or from each other for clamping the blade, or exposing the blade (or its seating) respectively, and which are con trolled in such movement by positive co operating non-reversible connecting means between such sections and actuating means therefor.

2. A safety razor blade holder as in claim 1, having a non-reversible worm gearing connection between the clamping sections and the actuating means therefor.

3. A safety razor blade holder according to claim 1 or 2, in which the actuating, means comprise a rotatable handle or handle portion.

4. A safety razor blade holder as in claim 1 or 2 or 3, having folding cap sections pivotally connected to the guard along opposite edges thereof.

5. A safety razor blade holder as in any preceding claim provided with folding cap sections provided with cut-away portions through which the cutting edges of the blade extend as the sections fold and flex the blade, and means for simultaneously moving said sections to and from clamping position.

6. A safety razor blade holder as in any preceding claim, in which the guard edges are in fixed relation with the folding clamping or cap sections and rotate therewith into and out of shaving relation with respect to the blade.

7. In a safety razor blade holder as in any preceding claim, a guard member having a spindle journalled therein adjacent to each edge, a cap section associated with each spindle, and a handle including a rotatable worm meshing with both spindles.

8. A safety razor blade holder according to any preceding claim comprising a guard, rotatable spindles mounted therein in spaced parallel relation and having gear teeth formed therein at opposite parts, a worm interposed between said spindles, directly meshing with the gear teeth thereof and disposed with its axis at right angles to the plane of the axes of the spindles, means for rotating the worm to rock the spindles, and cap sections carried by the spindles.

9. A safety razor blade holder adapted to flex a double-edge flexible razor blade and maintain it in the desired condition of flexure for shaving, in which the holder components are maintained as a unit assemblage when the holder is in the open position by the provision of cap sections which are connected to the guard so as to fold towards or away therefrom and towards or from each other for clamping the blade, or exposing the blade (or its seating) respectively, and which are so constructed and arranged as to be capable during their folding movement towards each other of flexing the blade and to leave both cutting edges of the flexed blade exposed for shaving.

10. A safety razor or safety razor blade holder substantially as described or shown.