Note: Descriptions are shown in the official language in which they were submitted.
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The invention relates to a shaving apparatus of the
type having a shear plate with hair entry apertures, said
apparatus comprising a drivable cutting unit with cutters,
each cutter being equipped with a lead cutter, which leads
in the direction of driving and which is movable relative
to the cutter.
; The lead cutters serve to slightly pull the hairs,
so that a better shaving result can be obtained. The
- distance over which the hairs can be pulled is limited by
the shape and dimensions of the cutter and the lead cutter
and by the properties of the hairs and the skin.
It is the object of the invention to eliminate this
restriction and this leads to a construction which is
characterized in that each cutter, in addition to the
said first lead cutter, is equipped with a second lead
. cutter which leads relative to the first lead cutter and
which second lead cutter is movable relative to the first
lead cutter.
A special embodiment is characterized in that each
cutter is provided with more than two lead cutters, each
second and further lead cutter being movable relative to
~: an adjacent preceding lead cutter.
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T.he invention is also embodicd
by a cutting unit as used in one of the embodiments
described in the foregoingt
The invention will now be
explained by means of a description of an embodiment
shown in the Figures.
Figure 1 is an elevation of a
shaving apparatus having three shear plates,
Figure 2 shows the shaving
apparatus of Figo 1 in side view and partly in a cross
sectional view ta~en on the line II-II in Fig. 17
Figu.re 3 shows the cu-tting mem-
ber with lead cutters in. perspective,
Figures 4, 5 and 6 i.llustrate
the operation of the lead cutters,
The shaving apparatus in
accordance with Figures 1 and 2 comprises a housi.ng 1~ of
which a part takes the form oI a shear plate holder 2 for
three shear plates 3. The shear plates 3 are formed with
20~ hair-entry apertures l~.
As i8 shown in the partial
! cross-section of Figc 2 a cutting unit 5 is situated on
.~ the inner side of a shear plate 3. This cuttin.g unlt 5,
which for the sake of clari.ty is only shown schematically
in Fig. 2~ comprises a cutting member wi.th cutters and
lead cutters, and is shown in perspective view and on an
enlarged scale in Fig. 3.
The cutting unit 5 is coupled
to the electric motor 10, ~y means of the hollow spindle
6 (Figo 2)~ the gear wheels 7 and 8 and the spindle 9,
so that the cutting unit is rotatable relative to the
associated shear plate 3O The gear wheel 7 is rotatably
journalled on a pln 11, which is mounted in a mounting
plate 120 T.he gear wheel 7 is formed wil;h a recess 13,
which is closed by a co~er pla-~e 11!. TiJ.i.s recess accommo-
dates the fl.ange 15 a-t the end o~ -the hollow spindle 6 r
By gi~ing the flange 15 a noll-rou.nd~ for e,~ample, sq1lare,
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shape and by eorre~ondingly shapin.g the recess 13, a
eoupli.ng is obtained for transmitting the rotary move-
ment of the gear wheel 7 to the spindle 6. The spring 16,
whieh for the greater part is disposed in the hollow
spindle 6 and whieh is tensioned between the hollow
spindle 6 and the gear wheel 7, exerts a force on the
spindle 6 in the direction o~ the cutting unit 5. As the
eylindrieal portion 17 of -the spindle 6 bears against the
. CUttillg unit 5, said foree is exerted on the eutting unit
l~ and via the eutting unit on the sh.ear plate 3, so that
the shear plate is urged against the shear plate holder 2
with the rim 18. The shear plate 3 together with the
eutting unit 5 and the spindle 6 ean be pressed inwards
against th.e aetion of the spring 16 as a result of exernal
forees, as may for example occur duri.ng use o~ the shaving
apparatus..
The eoupling for t:ransmitting
th.e rotary mo~ement between the spindle 6 and the eutti.ng
unit 5 :is obtainecl in that the spindle 6 is provided with
an end 19 of substantially rec-tangular eross-seetion. Th.is
end 19 i9 sltuated in a eorresponding eoupling aperture
20 of the eutting unit 5.
The eoupling wi.th the eleetrie
motor 10 deseribed in the ~oregoing is identieal :~or the
three eut-ting units of the apparatus in aeeordanee with
~igures 1 and 2, the three gear wheels 7 engaging with a
single eentrally disposed gear wheel 8 on the motor spindle
9.
The eu-tting uni.t 5 (Figure 3)
. eomprises a cutting member 21 which is essentially con-
stituted by a ceni;rQl member 22 which at its circumferenco
is p.ro~ided with cutters 23. The eentral bocly 22 has a
eoupling aperture 20. Each cutter 23 is pro~idecl with a
~ irst lea.d cutte:r 2ll- and a second lead cutte:c 25. The
lead cutte:rs 2~l are combined to a lead cutter ~m.it 26
which compr:i.ses a central porti.on 27 to ~hich the lead.
cutters Z/l are connected by~ eans o~ the arms 2~ In a
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similar way the lead cutters 25 form part oa a lead
cutter unit 29 with a central portion 3O and arms 31.
Owing to the elastic propertles of the arms 28 and 31
the lead cutters 24 and 25 are movable relative to the
associated cutters 23.
In the assembled condition of
the cutting lmit the central body 22 of the cutting
member 21 and the central portinn~ 27 and 3O of the lead
cutter units are connected to each other ~or exa.mple by
' spotwelding.
Figures 4 5 and. 6 schematicall-y
represent a side view of a part of the cut-ting unit 5 and
a part of the shear plate 3 and ser~e to illustrate the
operation of -the lead cutters. When a hair 32 is caught
15 in a hai.r entry aperture 4 the rotary mo~ement of the
cutting unit 5 will soon bring thc hair into contact with
the sharp edge 33 of the lead cutt;er 25 at the location A.
The sharp edge is such that it will slightly penetrate the
ha.ir 32 with.out cutting th.e ha:ir. J~le reaction force which
20 is exerted on the lead cutter 25 by the hair 32 will be
opposed to the direction of movement P. This force is to be
compensated for by the component N1 of the normal force N
which is exerted on the lead cutter 25 by the guide wall
34 of the lead cutter 2l~ (~igo '~). For the sake of simplici
25 ty the slight frictional forces between the lead cutters
24 and 25 have been neglectedO The collponent N2 of the
normal force N will cause the lead cutter 25 to slide
along the guide wall 3'~. The angle oG between the guide
wall 34 and the wall 35 of the lead cutter 2'l which engages
30 with the shear plate 3 should be smaller -than 9O.
As a result of inte~ alia the
n.atural elasticity o~ the shi.n the hair 32 will be taken
along by the lead cu.t-ter 25 un-til the sharp eclge 36 of
the lead cutter 2'l has reached the hair 3LI at the location
35 B (Fig~ 5). Under the in~l-uence of a sllllilar sys-tem of
: forces as illustrated i.n Fig. 4 the leacl cutter 2~ wil:L
: slide along the gu;.de wa:ll 37 of t;he cutter 23. l`he hair
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is now tal~en along by the ]ead cutter 2L~ unt~ -the cutting
edge 38 of the cutter 23 h.as reached the hair at the
. location C (Fig. 6). Subsequently, the hai.r 32 will be cut-
off by cooperation o~ the sh.ear plate 3 and the cutter
5 23. The leng-th AB over which a hair can be pulled by a
: lead cutter is inter alia limited by the dimensions of
the lead cutter, in particular the thickness D (Fig. ~)
; In theory the distance AC over wh.ich a hair can be pulled
can also be achieved wi.th a single lead cutter having a
1~0 thickness 2D. l`he bending moment relative to the shear
plate which is exerted on the hair 32 by the :Lead
cutter then ;has a maximum arm AC and is therefore theo
retically twice the bendi.ng moment exerted on the hair 32
in -the case of two lead cu.tters 2L~ and 25 in accorclance
with Figures ~ to 6, the maximum arm being only AB or BC,
: This bending moment as a result o~ which th.e hair tends to
be pressed against th.e inner side of the sh.ear plate 3 is
one o~ the main limiting ~actors in re~ect o~ the length.
over which the hair can be moved. By the use o~ two or more
lead cutters this length may there~ore be lncrease~ propor~
t:ionalJ.y.
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