Cutlery – Razors – With cooperating shearing blades
Reexamination Certificate
1998-08-18
2001-05-08
Young, Lee (Department: 3729)
Cutlery
Razors
With cooperating shearing blades
C030S043900, C030S346510
Reexamination Certificate
active
06226871
ABSTRACT:
This invention relates to a dry shaving apparatus of the type indicated in the prior-art portion of the main claim.
A dry shaving apparatus of the type initially referred to is known from U.S. Pat. No. 2,339,677. The shaving head formed of a shaving head frame and an outer cutter and an inner cutter is arranged on an upper housing surface of a housing for reciprocating movement transverse to the direction of movement of an inner cutter driven to oscillate in the longitudinal direction. To transmit the driving motion to the inner cutter on the one hand and to the shaving head on the other hand, a double eccentric device is provided on the rotary shaft of an electric motor fixedly disposed in the housing. The masses comprised of shaving head, inner cutter and double eccentric device which are driven for reciprocating movement in different directions by driving elements produce excessive vibrations perceivable to the user because of the development of loud noise in addition to causing handling discomfort.
A dry shaving apparatus of the type referred to in the foregoing is also known from DE-GM 1 711 665. In all embodiments of this known printed specification, the drive element of the electric drive mechanism is linked, likewise through transmission elements such as a gear mechanism or a double eccentric device or a double-armed lever, to both the inner cutter and the shaving head equipped with an outer cutter, in order to set the inner cutter and, in addition, the complete shaving head in motion. Considering the masses to be set in motion by the electric drive mechanism of this specification, which include the transmission elements and the inner cutter and, in addition, the complete shaving head assembly comprised of shaving head frame, outer cutter and inner cutter, the electric motor is required to deliver an increased power output which needs to be taken into account correspondingly in the design of the dry shaving apparatus. The masses needing to be accelerated in different directions due to the oscillations and to be decelerated as well, transmit oscillation couples to the housing of the dry shaving apparatus through the electric drive mechanism secured to the housing. This effect is noticeable on the housing in the form of unpleasant vibrations and loud noise under load.
From DE 3 631 120 A1 it is known to use eccentric balance weights to dynamically balance in a dry shaving apparatus the masses such as eccentric device, oscillatory bridge structure with coupling element as well as inner cutter, which are driven to reciprocate by an electric drive mechanism, that is, an electric motor, in order to suppress undesired vibrations. These balance weights which are associated with the electric drive mechanism necessarily require an increased power output of the electric drive mechanism, resulting directly in increased cost of the electric drive mechanism and, in cases where a dry shaving apparatus is equipped with rechargeable storage cells, in an increased consumption of stored energy and hence a reduced number of shaves per charge of the storage cells.
It is an object of the present invention to improve upon a dry shaving apparatus of the type identified in the foregoing.
According to the present invention, this object is accomplished in a dry shaving apparatus of the type initially referred to by the features indicated in the main claim.
This approach of the present invention affords a plurality of advantages. When the electric drive mechanism is started, the electric drive mechanism is excited to oscillate at least in opposition to the direction of movement of one or, where applicable, several cutting elements by the masses set in motion by the drive element and also by the friction occurring between the cutting elements provided. Because according to the present invention the electric drive mechanism is mounted for oscillation, this oscillating excitation, which in the hitherto conventional, standard rigid fastening of an electric drive mechanism to the shaver housing is transmitted from the electric drive mechanism to the shaver housing where it consequently produces unpleasant vibration and loud noise, rather than being transmitted to the housing, remains initially with the electric drive mechanism, causing it to oscillate about at least one axis. The electric drive mechanism hence follows the oscillatory motions forced upon it without significant effect on the housing of the dry shaving apparatus. This approach effects first a material reduction of housing vibration and noise under load that is derivable therefrom. According to the present invention, these oscillatory motions of the electric drive mechanism are utilized advantageously to set the shaving head of the dry shaving apparatus in oscillation. The oscillation of the shaving head and hence the cutting element fixed in the shaving head produces a relative motion between the skin and the cutting element. In consequence, tips of hair that are located in close proximity to the cutting element and threadedly engage therebetween only sparingly in the absence of oscillation are then in a position to penetrate the cutting openings of the cutting element in major quantities. In addition, the oscillation of the shaving head operates to lengthen the effective hair entrance openings in the cutting element in the direction of oscillation. The threaded hair is entrained by the cutting element configured as inner cutter, the cut being performed against the edge of the hair entrance opening in the cutting element configured as outer cutter. As the shaving head executes an oscillatory motion in the directions of movement A and B, the outer cutter moves against the inner cutter, thereby shortening during the cutting operation the length of displacement of a hair that has penetrated the hair entrance opening, whereby the hair is cut to a shorter length. The cutting performance of the dry shaving apparatus is thus significantly improved. Moreover, on account of the high oscillation frequency of the shaving head, a reduced sliding friction of the cutting element becomes effective on the skin.
An essential advantage of the present invention resides in that the oscillating excitation originating from the movable masses, rather than being transmitted to the housing of the dry shaving apparatus as is known from DE-GM 1 711 665, is transmitted, via the oscillatory mounting of the electric drive mechanism, to the movable shaving head. Hence the energy of the oscillating excitation is routed from a location in the housing where disturbing effects occur to a location where this energy can be put to use in advantageous manner. For lack of linkage of its drive element with the oscillatory shaving head, the electric drive mechanism is thus not required to supply driving power to this shaving head.
In a further configuration of this invention, provision is made for at least the shaving head and the electric drive mechanism to be mounted for oscillation as an oscillating mass about at least one common axis of oscillation.
To compute the position of the axis of oscillation for the electric drive mechanism in the housing, allowance must be made for the fact that the oscillating mass is formed by incorporating the oscillating mass of the electric drive mechanism as well as all components adapted to be set in oscillation by the oscillatory motions of the electric drive mechanism, such components including, for example, the shaving head, support arms, the bearing cage, the universal joint frame, the oscillatory frame, the supporting frame, the spring element and the oscillatory bridge structure for a cutting unit and/or by fitting additional oscillating masses.
In an advantageous embodiment of the present invention, the electric drive mechanism with the components adapted to be set in oscillation is mounted for oscillation about a first axis of oscillation which extends transversely to the directions of movement of the drivable cutting element.
A further advantageous embodiment of the present invention is characterized in that the electric drive mecha
Eichhorn Reinhold
Harms Michael
Hottenrott Sebastian
Junk Peter
Odemer Michael
Braun GmbH
Chang Rick Kiltae
Fish & Richardson P.C.
Young Lee
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