US3172201A

US3172201A - Shaver with roller guided drive

Info

Publication number: US3172201A
Application number: US295102A
Authority: US
Inventors: Messinger Werner; Wich Robert
Original assignee: Braun GmbH
Current assignee: Braun GmbH
Priority date: 1962-07-18
Filing date: 1963-07-15
Publication date: 1965-03-09
Anticipated expiration: 1982-03-09
Also published as: AT240214B; DE1168290B; GB978828A; CH413652A

Description

March 1965 w. MESSINGER ETAL 3,172,201

SHAVER WITH ROLLER GUIDED DRIVE Filed July 15, 1963 2 Sheets-Sheet 1 1 Fig.1

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Rosem- \JICJI March 1965 w. MESSINGER ETAL 3,172,201

SHAVER WITH ROLLER GUIDED DRIVE Filed July 15, 1963 2 Sheets-Sheet 2 Fig. 3

Inventors WERNER M ESSI NGER Roma \JICH j 71 5mm 771...

ATTORNEYS United States Patent C) 3,17 2,201 SHAVER WITH ROLLER GUDED DRIVE Werner Messiuger and Robert Wicli, Frankfurt am Main,

Germany, assignors to Braun Aktiengeselischaft, Frankfurt am Main, Germany, a German company Filed July 15, 1963, Ser. No. 295,102

Claims priority, application Germany, Huly 18, 1962,

Claims. (6!. -4332) This invention relates in general to power-driven shavers, and in particular to a new and useful power-driven shaver having a stationary cutter which partially envelopes a reciprocating movable cutter which movable cutter is driven by means of a slide which oscillates on roller bearings.

The present invention has particular application to a power-driven dry shaver of a type which employs a freely flexible, perforated head plate or foil which serves as a stationary cutter and which overlies a reciprocating movable cutter in the form of a knife block. The perforated head plate has a configuration conformable to the movable knife block or cutter, and the cutter is urged against the inner surface of the head plate by spring means as it is reciprocated. The knife block is advantageously connected or coupled with a driving member, such as a rocker arm or an eccentric, through a universal joint or Cardan joint. In dry shavers of this type the knife block is reciprocated relative to the stationary foil, either directly by a rocker arm or eccentric driven by the motor, or

by means of an intermediate element which permits the knife block to perform a limited Cardanic movement. In some instances the knife block is urged against the stationary foil or cutter head by means of springs and is moved by means of a slide member which is biased by the spring to provide a constant and sung engagement over the entire operating stroke of the knife block. In arranging the springs on the slide member and in dimensioning the springs with regard to the required contact pressure, consideration must be given to the fact that the springs, in the course of the reciprocating movement of the knife block, assume their most relaxed or extended position at each end of the knife block stroke, while the springs are most compressed in the center position of the knife block stroke. When helical or coil springs are employed, not only are they stressed in regard to tension and pressure, but also in respect to twisting or bending.

Thus, with prior art constructions springs must be selected with sufficient strength to prevent movement of the knife block away from the perforated foil, particularly at the end positions of the movement of the knife blocks. This is so because shavers of this type require, for efiicient cutting action, that the active portions of the movable and stationary cutters be maintained in exceedingly close and precise engagement throughout the area of cut and in all positions of the movable cutters throughout their stroke.

With the above in mind it can be seen that in the center position of the knife block the pressure or contact force generated by the springs is larger than is actually required. This, of course, unnecessarily increases the friction between the cooperating cutter portions and requires not only greater energy to move the cutter elements relatively, but also increases the wear on the knife edges and on the inner surface of the stationary cutting foil.

In accordance with another known dry shaver, the knife block is driven by a motor through a rocker arm and the slide member, so that the interposed spring is not deformed during the working stroke. In such a known embodiment the slide member is mounted on a swing arm in the manner of an articulated quadrangle, so that the swinging takes place not only backwardly and forwardly in the cutting direction, but also perpendicularly thereto. In this manner 3,172,201 Patented Mar. 9, 1965 'ice the slide member stresses the spring periodically only. However, such a construction does not overcome the disadvantage that the pressure and contact force exerted by the springs is larger in the center position of the knife block than is actually required.

With another known construction a spring is arranged to bear against the slide which is guided exactly parallel to the movement of the knife block, and the superimposed knife block and slide members are jointly driven by the rocker arm from the motor so that the helical spring assumes a slanted or oblique position when the knife block has reached the extreme positions of its stroke. With a construction of this nature the spring is alternately bent toward one side or the other and the aforementioned disadvantages are also present.

In accordance with the present invention there is provided a driving arrangementbetween the motor and the knife block which is free of the disadvantages of the prior art constructions, and which arrangement includes springs oriented to provide uniform contact pressure between the movable and stationary cutters throughout the entire length of the stroke of the movable cutter. In accordance with a preferred embodiment a slide member is mounted on rollers between two parallel surfaces of the casing of the shaver and is imparted with a back and forth movement while it is guided in a parallel manner by the rollers. The slide member is connected, by a bolt member, to the movable cutter by a connection permitting pivotal movement of the cutter. By means of the inventive arrangement, the springs uniformly stress the movable cutter throughout its entire stroke, and the pressure or contact force exerted by the spring can be dimensioned so as to always maintain an optimum contact pressure. With the invention the maximum hearing or contact pressure required for the spring is thus much smaller than in the prior art constructions. The friction which takes place in the mounting of the slide member is comparatively small relative to the gain in friction in the cutting system, and for this reason this additional friction can be disregarded in computing the required force of the spring.

In one embodiment the slide member is mounted so that on each side of the driving connection one surface of the slide member is guided by two guide tracks formed by the rollers, arid the other side is guided by a single guide track formed by the rollers. These guide tracks are arranged in a special manner in the form of a three-point mounting in the plane of movement of the knife block, or in a plane which is parallel to the plane of movement of the knife block. The lower guide surface is advantageously provided at a plate member which is urged against the slide by the pressure of a supporting spring.

Accordingly it is an object of the invention to provide an improved dry shaver construction.

A further object of the invention is to provide a dry shaver which includes a driving motor for reciprocating a knife block which is enveloped by a stationary cutting head and wherein the driving connection between the motor and the knife block includes a slide which is supported and guided on roller bearings for parallel to and fro movement.

A further object of the invention is to provide a powerdriven dry shaver which includes a reciprocating cutting member in the form of a knife block which is urged by spring means against the inner surface of a stationary cutter in the form of a perforated, flexible foil, and which includes a driving electric motor arranged to move a slide, which is connected to the knife block, baekwardly and forwardly, the slide being guided by roller bearings for parallel back and forth movement.

A further object of the invention is to provide a powerdriven dry shaver which is simple in design, rugged in construction and economical to manufacture.

.tion.

7 stroke.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specifica- For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described preferred embodiments of the invention.

In the drawings:

FIG. 1 is a partial transverse section through the upper portion of a dry shaver constructed in accordance with the invention, the section being taken along line 11 of FIG. 2;

FIG. 2 is a longitudinal section of the shaver indicated in FIG. 1; and

FIG. 3 is a side view of the shaver. Referring to the drawings in particular, the invention embodied therein comprises a power-driven dry shaver having a reciprocating movable cutter or knife block generally designated 1.

inafter.

The upper portion of the casing 5 is covered by a cap or cover member which is releasably secured thereto.

The cap 10 is provided with an opening 32 to permit passage of the spring 2 which is mounted on the slide member 6, and to also permit passage of a driving bolt member '7 which is secured to the slide member. A substantially U-shaped bearing member or yoke 29 is rotatably mounted on the bolt 7 and is held downwardly -to compress the spring 2 by means of a disc or washer 19. The bearing'member 20 has spaced arm portions 20a and Ztib which rotatably carry a pin 21 which is connected at each of its ends to the knife block .1 in a manner permitting the knife block to pivot slightly about the axis of the pin. The slide 6 has a fork-shaped'lower portion 8 forming an elongated slot 8a into which extends an eccentric pin l which is carried on the end of a drive member or shaft 9. in some instances a rocker arm is employed instead of an eccentric pin 23 for driving the slide 6.

In accordance with the invention the slide 6 is mounted in a manner to permit its'guiding movement for transmitting a driving motion to the cutting block it with'a minimum offriction during the course of'its complete At the upper inner surface or bearing surface 11 of the cap 10 there are provided grooves 12 which form guides for upper bearing balls 13. The balls 13 are carried in the grooves 12 and similar grooves formed in an upper surface 6a of the slide 6. The slide 6 bears downwardly on balls 14 which are carried in comple- -mentary grooves 15 formed in the lower surface 6b of the slide 6 and the upper surface or bearing member 16 :of a plate member 17. The plate member 17 is advan .side of the plate member 17 and is supported on the casing 5. The spring 18, while not absolutely essential since the plate 17 could be mounted directly on the casing 5, provides for compensating for any bearing play of the

balls

13 and 14.

vantageously arranged symmetrically to the plane of movement, so that at each end of the slide there is formed a three-point mounting, that is, one at the bottom and two on top. Of course, the arrangement can be advantageously reversed so that there would be two balls on the bottom and one on the top of each side of the slide 6.

When the motor 22 runs to rotate the drive member or shaft 9, the slide 6 is reciprocated between the two bearing surfaces 11 and 16 and uniformly moves the knife block 1 by means of the bolt 7 backwardly and forwardly. Since the spring 2 bears upwardly on the knife block 1 and downwardly on the slide which is guided exactly parallel to the knife block, the spring is constantly and uniformly stressed and is not subject to any bearing stresses and hence will not be subject to any pressure, bending or twisting.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. A power-driven shaver construction comprising a housing, a stationary cutter mounted on said housing, a movable cutter block movable in cooperative engagement with said stationary cutter, means biasing said movable cutter block against said stationary cutter, a driving memher in said housing, a movable slide connected to said driving member for movement thereby and connected to said movable cutter block to move said cutter block, said housing including a first member extending above said slide, .a plate member located below said slide, and roller means carried by said plate member and said first member sup- 7 porting said slide for movement.

In order to insure that the slide is guided during its 7 '61; in the example illustrated), and four balls all designated 13 are provided on the opposite side of the slide 6 (the upper face-6a, as illustrated). The halls are ad- 2. A power-driven shaver according to claim 1, wherein said roller means includes at least two rollers on each side of the center line of said slide bearing against one side of said slide, and one roller bearing against the opposite side of said slide.

3. A power-driven shaver comprising a housing, a stationary cutter in the form of a perforated flexible foil mounted on said housing, a movable cutter block -movable in cooperative engagement with said stationary cutter, a driving member, a movable slide connected to said driving member for movement thereby and connected to said movable cutter to move said cutter, means carried by said porting said plate member on said housing.

4. A power-driven shaver comprising a housing, a stationary cutter in the form of a perforated flexible foil mounted on said housing, a movable cutter block movable in cooperative engagement with said stationary cutter, a driving member, a movable slide connected to said driving member for movement thereby and connected to said movable cutter to move said cutter, means carried by said slide .to bias said movable cutter blocks against said stationary cutter, roller'means supporting said slide for substantially coplanar movement in said housing, the connectionbetween said slide and said movable cutter block including an upstanding bolt, a yoke member pivotally mounted on said bolt, and a bearing pin rotatably supported on said yoke member and connected at each end t said movable cutterblock.

V 5. A power-driven shaver comprising a housing, a stationary cutter mounted on said housing, a movable cutter block movable incooperative engagement with said stationary cutter, a driving member in said housing, a movable slide connectedto said driving member for mov ment thereby, a boltprojecting fromsaid slide member,

5 6 said cutter block being mounted on said belt for move- 2,536,015 12/50 Konrad 30 43.6 ment axially of the latter towards and away from said 2,819,518 1/58 Lussier 3034.1 stationary cutter, spring means carried by said slide mem- 2,952,908 9/60 Starre et a1. 30-43.5 her to bias said cutter block towards said stationary cut- 3,045,246 7/62 Akerib 30-4392 ter, said housing including a first member extending above 5 3,105,298 10/63 C-arissimi 30-4392 said slide, a plate member located below said slide, and FOREIGN PATENTS roller means carried by said plate member and said first member supporting said slide for movement. 1,145958 6/59 Germany- 628,599 9/49 Great Britain. References Cited by the Examiner 10 857,095 12/60 Great Britain.

UNITED STATES PATENTS WILLIAM FELDMAN, Primary Examiner.

2,440,114 4/48 Page 3043.3 MYRON C. KRUSE, Examiner.

Claims

1. A POWER-DRIVEN SHAVER CONSTRUCTION COMPRISING A HOUSING, A STATIONARY CUTTER MOUNTED ON SAID HOUSING, A MOVABLE CUTTER BLOCK MOVABLE IN COOPERATIVE ENGAGEMENT WITH SAID STATIONARY CUTTER, MEANS BIASING SAID MOVABLE CUTTER BLOCK AGAINST SAID STATIONARY CUTTER, A DRIVING MEMBER IN SAID HOUSING, A MOVABLE SLIDE CONNECTED TO SAID DRIVING MEMBER FOR MOVEMENT THEREBY AND CONNECTED TO SAID MOVABLE CUTTER BLOCK TO MOVE SAID CUTTER BLOCK, SAID HOUSING INCLUDING A FIRST MEMBER EXTENDING ABOVE SAID SLIDE, A PLATE MEMBER LOCATED BELOW SAID SLIDE, AND ROLLER MEANS CARRIED BY SAID PLATE MEMBER AND SAID FIRST MEMBER SUPPORTING SAID SLIDE FOR MOVEMENT.