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Electric Razor, claimed for Stahly Live Blade

PatentUS2054418

InventionSafety Razor

FiledFriday, 27th April 1934

PublishedTuesday, 15th September 1936

InventorIlse Hartmann

OwnerKupfer-Asbest-Co. Gustav Bach

LanguageEnglish

Other countriesDE651039

This patent number can be found on the head of the Stahly Live Blade razor.

For a full resolution version of the images click here

A PDF version of the original patent can be found here.

Patented September 15, 1936 2,054,418
United States Patent Office
2,054,418 SAFETY RAZOR Ilse Hartmann, née Böhm, Germany, assignor to Kupfer-Asbest-Co., Gustav Bach, Heilbronn-on-the-Neckar, Germany. Application April 27, 1934. Serial No. 722,775. In Germany May 4, 1933 5 Claims. (Cl. 30—45)

My invention relates to safety razors of the kind in which a cutting movement is imparted to the blade by means of a suitable supply of energy.

It has already been suggested to impart to the razor blade reciprocating movement parallel to its cutting edge, i. e., at right angles to the direction of cutting, by means of an electromagnet, and it has also been suggested to accomplish a similar result by a crank mechanism operatively connected to an electric motor. It has further been suggested to rotate circular blades by means of a spring motor in order to improve the cutting action. All these apparatuses, however, involve the drawback that the blade is permanently pressed to the skin during the use of the apparatus, with increased risk of cutting into the skin of the user, and that the blade exerts a painful pull on the hair. Apparatus in which the blade slides in guides, involve the additional drawback that the power demand is increased by the friction of the blade in the guides.

It is an object of my invention to improve safety razors having a driven blade by imparting to the blade a movement by which the cutting action is considerably improved. According to my invention this is accomplished by causing the blade to vibrate at high frequencies in such a manner that each point of the blade is moved along a closed curved path, for instance, a circular or oval path, while the cutting edges of the blade remain parallel to the longitudinal axis of the razor head. In consequence thereof the blade is vibrated in such manner that a gyratory cutting action is obtained wherein each point of the cutting edge simultaneously makes substantially circular oscillations of equal amplitude in a plane which substantially coincides with a plane perpendicular to the axis of the handle. The resulting cutting action is very advantageous. In order to impart high frequency vibrations to the razor blade preferably the razor head is moved in a similar manner. In apparatuses of this kind it does not matter what position the head has with respect to the razor, and in this respect my apparatus compares favorably with apparatuses whose blades are reciprocated along a straight line only, as I may screw the head into the handle to a greater or lesser extent so that the curvature of the blade may be adjusted in similar manner as in safety razors well known in the art.

The vibratory movement of the razor head is preferably produced by rotating a solid member by means of a motor about an axis eccentric to the gravity centre of the member. The member tends to rotate about an axis passing through its own gravity center and in consequence thereof it imparts circular oscillations to its bearings in the razor head, and to the head itself.

It should be understood that an elliptical or oval oscillation may be imparted to the blade instead of a circular one.

In the drawing affixed to this specification and forming part thereof some embodiments of my invention are illustrated diagrammatically by way of example.

In the drawing,—

Fig. 1 is a plan view of a razor blade, illustrating the oscillating movement thereof,

Fig. 2 is an elevation, partly in section, of an embodiment in which an electromotor is arranged in the casing of the razor and supplied with current from a current line,

Fig. 3 is an elevation of a razor head equipped with camming means for clamping the blade,

Fig. 4 is a section on the line IV—IV in Fig. 3,

Fig. 5 is an elevation, partly in section, of another embodiment of my invention, in which current is supplied to the motor in the casing by a battery arranged in the handle of the razor.

Referring first to Fig. 1, 6 is a razor blade of the usual shape provided with perforations 22 and straight cutting edges 30. When the blade is inserted into the razor and oscillated in the manner described hereinafter each point of the razor, for instance point 1, describes a circular or oval path. The circular path described by a point 1 is indicated at 31, in Fig. 1, on an exaggerated scale. While the razor blade carries out oscillations of this kind the cutting edges 30 are subjected to parallel translations so that they always remain parallel to the longitudinal axis of the blade.

Referring now to Fig. 2, 2 is the casing of the razor in the lower portion of which an electromotor 3 is arranged. The shaft 4 of the motor 3 is supported by bearings 34 and 35, bearing 35 being arranged in the head portion 32 of the razor. 16 is the stator winding of the motor to which current is supplied from a line (not shown) by means of a plug 18 and a connection 17. 20 is the pole pieces of the motor energized by the winding 18. 19 is the rotor of the electromotor, the shaft 4 of which extends through the hollow central portion of the casing 2. It should be understood that a spring motor or the like (not shown) may be used instead of an electromotor. To the upper end of the motor shaft 4 a solid member, for instance, a fly wheel 5, is eccentrically secured. As will be seen from the drawing, the fly wheel 5 is arranged in the head portion 32 of the razor, to which the guard plate 21 is screwed at 33. 7 is a clamping plate provided with studs 8 engaging the perforations 22 of the blade 6 and corresponding perforations 36 and 37 provided in the guard plate 21 and a suitably shaped blade spring 9 arranged at the lower side of the guard plate 21 for engaging in grooves 11 of the studs 8. If desired, the clamping plate may be connected to the razor by means of a screw connection well known in the art, and not illustrated.

The operation of this apparatus is as follows:—

The blade 6 is put on the guard plate 21 and the clamping plate 7 is secured to the razor head so that its studs extend through the perforations 36 and 37, and the grooves 11 provided in the studs 8 are engaged by the spring 9, the blade 6 being clamped between the guard plate 21 and the clamping plate 7. The motor is energized by putting the plug 18 into a suitable wall socket (not shown) or the like and in consequence thereof its rotor 19 rotates. This rotation is transmitted to the fly wheel 5 by means of shaft 4. Since, however, the gravity center of the fly wheel is not in alignment with the shaft 4, the fly wheel, when rotated, exerts a force on the bearing 35 which is transmitted to the razor head 32 and causes the head to oscillate along a circular path with respect to the casing or handle 2 of the razor. A corresponding movement is imparted to the razor blade 6 on the razor head.

As compared with the crank mechanism referred to, or with a mechanism having two eccentrics rotating in unison, by which a similar result might be accomplished, my mechanism, as described with reference to Fig. 2, involves the advantage of lower power demand, as internal frictional resistance is practically eliminated.

If it is desired to adjust the curvature of the blade 6 an adjustable clamping device as shown in Figs. 3 and 4 may be used. In these figures the razor head 32 is provided with cams or ribs 23 in the shape of portions of a male external interrupted thread adapted to engage the grooves 11 provided in the studs 8. The thread portions 23 are slightly inclined and by screwing the razor head more or less into the guard plate 21 the clamping plate 7 is more or less approached to the guard plate, the blade 6 being more or less curved thereby. It should be understood, however, that the same effect may be obtained by providing the clamping plate with means (not shown) well known in the art for screwing it to the handle of the razor.

Referring now to Fig. 5, the winding 16, the pole pieces 20 and the rotor 19 of the motor 3 are arranged in the upper portion of the casing 2 and a dry cell battery 13 is arranged in the lower portion or handle 15 of the casing. 24 is a switch provided at the lower end of the handle portion 15 for closing the circuit of the motor. The connections between the battery 13 and the motor 3 are not shown and may be designed in similar manner to the connections in pocket lamps or the like. Since the energy necessary for imparting the oscillating movement to the blade is very small it is sufficient to provide a single dry cell battery 13, as shown in Fig. 5, for driving the blade.

The operation of the razors shown in Figs. 3 to 5 is substantially the same as that of the razors shown in Fig. 2, and does not require detailed description.

I wish it to be understood that I do not desire to be limited to the exact details of construction shown and described for obvious modifications will occur to a person skilled in the art.

I claim:—

1. A safety razor comprising in combination, a handle, a blade holder and blade mounted on said handle substantially at right angles to the longitudinal axis thereof and means for causing said blade holder and blade to execute high frequency vibrations along a closed curved path in a plane substantially at right angles to said axis.

2. A safety razor comprising in combination, a hollow handle, a blade holder and blade mounted on said handle substantially at right angles to the longitudinal axis thereof, a spindle rotatably mounted in said handle, a gyrating mass eccentrically mounted on said spindle and means for rapidly rotating said mass in said handle to set said handle vibrating at a high frequency, thereby rapidly moving the blade mounted thereon in a closed curved path in a plane at right angles to said axis, the cutting edges of said blade being subjected to parallel translations.

3. A safety razor comprising in combination, a hollow handle, a blade holder and blade mounted on said handle substantially at right angles to the longitudinal axis thereof, a spindle rotatably mounted in said handle, a gyrating mass eccentrically mounted on said spindle and means for rapidly rotating said mass in said handle while maintaining said mass out of direct contact with said handle, blade holder and blade, thereby setting said handle vibrating at a high frequency and causing the blade mounted thereon to rapidly move in a closed curved path in a plane at right angles to said axis, the cutting edges of said blade being subjected to parallel translations.

4. A safety razor comprising in combination, a hollow handle, a blade holder and blade mounted on said handle substantially at right angles to the longitudinal axis thereof, a spindle rotatably mounted in said handle, a gyrating mass eccentrically mounted on said spindle and an electric motor also mounted on said spindle for rapidly rotating said mass in said handle, thereby setting said handle vibrating at a high frequency and causing the blade mounted thereon to rapidly move in a closed curved path in a plane at right angles to said axis, the cutting edges of said blade being subjected to parallel translations.

5. A safety razor comprising in combination, a hollow handle, a blade holder and blade mounted on said handle substantially at right angles to the longitudinal axis thereof, a spindle rotatably mounted in said handle, a gyrating mass eccentrically mounted on said spindle and an electric motor also mounted on said spindle and a source of current in said handle for rapidly rotating said mass in said handle, thereby setting said handle vibrating at a high frequency and causing the blade mounted thereon to rapidly move in a closed curved path in a plane at right angles to said axis, the cutting edges of said blade being subjected to parallel translations.

Ilse Hartmann, née Böhm.