US3399454A - Mounting means for the lower reciprocable bolt blade of a cutter head for a dry shaver - Google Patents

Description

Sept. 3, 1968 E. LISKA 3,399,454

MOUNTING MEANS FOR THE LOWER RECIPROCABLE BOLT BLADE OF A CUTTER HEAD FOR ADRY SHAVER 3 Sheets-Sheet 1 Filed Dec. 6, 1965 Sept. 3, 1968 E s 3,399,454

MOUNTING MEANS FOR THE LOWER RECIPROCABLE BOLT BLADE OF A CUTTER HEAD FOR ADRY SHAVER 3 Sheets-Sheet 2 Filed Dec. 6, 196:

#76. 5 9 FIG. 6

Sept. 3, 1968 E. LISKA MOUNTING MEANS FOR THE LOWER RECIPROCABLE BOLT BLADE OF A CUTTER HEAD FOR ADRY SHAVER 3 Sheets-Sheet 5" Filed Dec. 6, 1965 5i EEEEEEEE iE- QE United States Patent 3,399,454 MOUNTING MEANS FOR THE LOWER RECIPRO- CABLE BOLT BLADE OF A CUTTER HEAD FOR A DRY SHAVER Erich Liska, Hitzendorf, Styria, Austria, assignor to Payer- Lux Eduard Payer, Graz, Styria, Austria, 2 company Filed Dec. 6, 1965, Ser. No. 511,814 Claims priority, application Austria, Dec. 9, 1964, A 10,400/64 2 Claims. (Cl. 3043.92)

ABSTRACT OF THE DISCLOSURE A cutter head for dry shavers in which a lower blade re'ciprocable in a predetermined direction in contact with a perforated stationary blade has secured thereto the first end of aresilient element with the second end of the resilient element bearing on a blade support detachably connected to the cutter head body for providing an abutment for the second head. The resilient element is arranged for urging the lower blade against the stationary blade with the abutment being provided with a slide face and the second end of the resilient element being provided with a slide member bearing on said slide face and displaceable in a predetermined direction relative to the abutment along the blade support.

This invention relates to a cutter head for dry shavers, e.g., electric razors, which cutter head comprises a perforated stationary blade held on the cutter head body, and a reciprocable lower blade urged against the stationary blade and supported by at least one resilient element on a blade support or carrying frame detachably connected to the cutter head body.

In connection with cutter heads of this type, it is known to provide for the attachment to the lower blade of one end of the springs which constitute the resilient elements and for the attachment of the other end of these springs to the carrying frame, preferably by gripping. In shavers provided with such a cutter head, the cutter head body together with the lower blade can be removed and replaced by another cutter head. In cutter heads of the kind described, the attachment of the spring ends to the carrying frame and to the lower blade must be absolutely reliable because otherwise the Spring ends will come loose as a result of the movement of the lower blade and may then give rise to damage. Besides, the lower blade does no longer snugly contact the stationary blade when one spring end has come loose. A further disadvantage of these known designs is that the springs are liable to break under the buckling and bending stresses to which they are subjected unless the springs are of expensive, special spring material.

Another dry shaver is known in which the lower blade is directly supported by the housing for the drive motor, and four ball bearing assemblies are interposed between the lower blade and said housing. In this case, the stationary blade is stretched about the lower blade and is not secured in a separate cutter head body but the two longitudinal edges of this stationary blade are anchored in the housing for the drive motor. For this reason, this known shaver can be used only with a single blade assembly and no provision is made for a different assembly, such as a cutter head comprising a comb. Moreover, this design is objectionable in that the lower blade is not resiliently urged against the stationary blade.

In another known cutter head, said lower blade is supported at its ends by balls or annular rollers which roll on spring guide pins associated with coil springs mounted in guide cylinders provided in the base. This design is undesirable in that the stroke of the lower blade must necessarily be small because special stops in the form of pivot pins must be provided to avoid an angular misalignment of the spring guide pins. I

In a cutter head of the type described initially hereinbefore, the above-mentioned disadvantages are avoided according to the invention in that at least one end of the resilient element is displaceable at least in the direction of movement of the lower blade. The essential advantages of the present design are that the life of the resilient element is increased and the resistance presented to the drive systern is reduced. This enables either a reduction in driving power or an increase in cutting force.

In carrying out the invention, the displaceable end of the resilient element is suitably connected to a slide member and each slide member is desirably snported by a slide face which is preferably provided on the carrying frame.

In another preferred embodiment, the displaceable end of the resilient element is supported by revolvable elements which may be mounted in the carrying frame, with a slide member being interposed, if desired, between the displaceable end of the resilient element and the revolvable elements. In this case, the revolvable elements are desirably mounted with the aid of a retainer and this retainer embraces a portion of the carrying frame. In these preferred embodiments, one end of the resilient element is preferably firmly secured to the lower blade.

Another preferred embodiment is distinguished in that the revolvable elements are rollers, with each roller having a shaft, arranged for a displacement normal to the hearing surface of the carrying frame in a carrier firmly connected to the lower blade, and said shaft is spring-cushioned by means of a spring mounted on the lower blade.

In a cutter head of this design, any wear will be compensated for by an automatic readjustment of the rollers, and the life of the stationary blade and of the cutter head as a whole will be prolonged. In addition, flutter of the lower blade and chafing on the stationary blade will be avoided. Another advantage of this design resides in that the required coupling, the retainer for the rollers, the mounting-means for the rollers and the spring retainer are combined in a single component which consists of the carrier. This carrier may be injection-molded from plastic material so that the weight is also reduced.

The invention will be explained more fully with reference to illustrated embodiments shown on the drawing, in which FIG. 1 is a longitudinal sectional view showing a cutter head,

FIG. 2 a sectional view taken on line II-II in FIG. 1,

FIG. 3 a longitudinal sectional view showing a different embodiment of a cutter head, and

FIG. 4 a sectional view taken on line IVIV in FIG. 3,

FIGS. 5 and 6 show special designs of resilient elements,

FIG. 7 is a longitudinal sectional view showing a further cutter head illustrating the invention,

FIG. 8 a transverse sectional view taken on line VIIIVIII of FIG. 7 and showing the cutter head thereof, and

'FIG. 9 a broken-away perspective view showing a carrier for the rollers.

Each of the cutter heads shown in FIGS. 1 to 4 is provided with a perforatedstationary blade 1 which is held on acutter head body 33. A reciprocablelower blade 2 is provided under thestationary blade 1 and is supported by a blade support, preferably acarrying frame 3, which is detachably connected to thecutter head body 33. The carryingframe 3 is held by twoclamping bars 4 secured by screws 5 to thecutter head body 33. Theclamping bars 4 are formed withprojections 6 which engagerecesses 7 of thecarrying frame 3. The screws 5 serve also for securing thestationary blade 1 so that the blade is preferably held only at its longitudinal edges. Thestationary blade 1 is suitably formed with punched elongalte'd holes through which the screws extend and which screws are threaded into theclamping bars 4. A certain play of thestationary blade 1 may be provided for to enable a displacement thereof such as by the provision of sleeves, which are fitted on each of the screws 5. In this way, thestationary blade 1 can conform to thelower blade 2 and provide a yielding guide for the lower blade which is independent on the precision with which the drive mechanism has been installed. Thestationary blade 1 may be curved approximately in accordance with a parabola, and thelower blade 2 may have semicylindrical cutting faces. Thelower blade 2 may be pivotally movable and laterally displaceable and is supported on thecarrying frame 3 by two resilient elements consisting ofcoil springs 8. One end of eachcoil spring 8 is secured to thelower blade 2 by a pin 9 having a shoulder and preferably of plastic material. The other end of each spring is connected by apin 11 to aslide member 10 preferably of plastic material. Thepins 9 and 11 are firmly gripped by the ends of thespring 8.

According to FIGS. 1 and 2, theslide member 10 bears on aslide face 12, which is provided on the carryingframe 3 and consists preferably of metal, particularly steel, or sintered material, such as graphite bronze. Theslide face 12 is laterally limited bybulges 13 or the like formed in the carrying frame. Thebulges 13 provide a travel path for enabling theslide member 10 to move along with the reciprocable lower blade in said path.

According to FIGS. 3 and 4, eachslide member 10 is supported by revolvable elements in the form ofrollers 14. The latter are mounted in aretainer 15 of plastic material and embraces aportion 16 of thecarrying frame 3.

FIG. 5 shows acoil spring 18, the ends of which are smaller in diameter than the intermediate portion. The use of such springs has the additional advantage that in spite of the gripping of thepins 9 and 11 or the like, the ends of these springs act like articulated joints so as to reduce the stress imparted to the springs whereas the intermediate portion resists buckling due to its larger outside diameter.

FIG. 6 shows anelement 19 of rubber or plastic material which serves as a resilient element and has the abovementioned advantages. The ends of this element are preferably tapered and gripped bycaps 20 and 21, respectively. One of said caps constitutes a slide member. The other is rigidly secured to thelower blade 2 or to the carryingframe 3.

In the embodiment shown in FIGS. 7 to 9,parts 1 to 7 and 33 are the same in design and arrangement as in the preceding embodiments.

However, thelower blade 2 is provided withrollers 22 which bear on a bearingsurface 23 of the carryingframe 3. In the embodiment shown, tworollers 22 are provided at the front and rear ends, respectively, of thelower blade 2. Eachroller 22 has ashaft 24 which is guided at each end of the roller in anelongated aperture 25 which extends normal to the bearingsurface 23 and is guided by acarrier 26 firmly connected to thelower blade 2.

The free ends ofarms 27 of aresilient yoke 28 engage the ends of eachroller shaft 24. This yoke tends to urge theroller 22 away from thelower blade 2. Thearms 27 of theyoke 28 are connected by across-bar portion 30 held in arecess 31 of thecarrier 26 and extend around projections or pins 29, which protrude laterally from thecarrier 26.

In order to prevent lateral movements of therollers 22 and ofthe'lower blade 2, the bearingsurface 23 may be provided with ashallow guide groove 32, the side walls of which are engaged by the ends of therollers 22. As therollers 22 are mounted on the blade side in such a manner that they are nondisplaceable transversely to the direction of movement of thelower blade 2, the blade is not capable of performing a transverse movement.

Thecarrier 26, which is firmly connected to thelower blade 2, consists preferably of a single injection-molded piece of plastic material and is provided with a coupling portion.

The operation of theinvention is as follows:

In each embodiment, thelower blade 2 is reciprocable in a predetermined direction in contact with thestationary blade 1 and tworesilient elements 8 and 28 respectively, function for urging theblade 2 against theblade 1. Each of the resilient elements is secured to the lower blade and is provided with an end displaceable relative to the blade support which is a carrying frame. In FIGURES 1 and 2, eachelement 8 is provided with aslide member 10 sliding on theblade support 3 while in FIGURES 3 and 4revolvable elements 22 roll between the slide member and the blade support. In FIGURES 7-9 the ends of theresilient elements 28 rest on theshafts 24 of therollers 22 which roll on the carryingframe 3.

This invention is not to be confined to any strict conformity to the showings in the drawings but changes and modifications may be made therein so long as such changes or modifications mark no material departure from the spirit and scope of the appended claims.

What I claim is: p

1. A cutter head for dry shavers comprises a cutter head body, a perforated stationary blade held on said cutter head body, a blade support detachably connected to said cutter head body, a lower blade reciprocable in a predetermined direction in contact with said stationary blade, and at least one resilient element having first and second opposite ends, said first end being secured to said lower blade, said second end of the resilient element secured to a slide member, said support having a slide face on which said slide member bears, said slide member being slidable along with the reciprocable lower blade and said resilient element being arranged for urging said lower blade against said stationary blade.

2. The cutter head as set forth inclaim 1, in which said blade support is formed with bulges, which limit said slide face in a direction which is at right angles to said predetermined direction.

References Cited UNITED STATES PATENTS 2,141,582 12/1938 Wimberger 30-34.1 2,236,760 4/1941 Muros et al 30-4392 2,273,524 2/1942 Jensen et al 30-4392 2,296,134 9/1942 Wright 30-4392 2,472,853 6/1949 Lorenz 3043.6 2,702,938 3/1955 Jepson 30-4392 2,819,518 1/1958 Lussier 30-34.1 2,859,513 11/1958 Bylund 30-4392 2,867,737 1/ 1959 Bylund 30-4392 X 3,074,161 1/1963 Liska 30-4392 3,169,313 2/1965 King 30-4392 FOREIGN PATENTS 524,412 8/1940 Great Britain.

451,739 9/1949 Italy. 378,572 6/ 1965 Switzerland.

MYRON c. KRUSE, Primary Examiner. I

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