Note: Descriptions are shown in the official language in which they were submitted.
37
The invention relates to a shaving apparatus having a shear plate with
hair-entrance apertures and a cutting unit which is rotatable relative to the
shear plate, which cutting wnit comprises a cutting member, which is substan-
tially constituted by a central body which is provided with cutters and which
cutting member is equipped with lead cutters which are movable relative to the
cutters, which lead cutters are secured to the central body of the cutting
member by means of connecting arms.
In a known shaving apparatus of this type, the cutting member has
lead cutters which are fixed to the cutting member by gluing or spot-welding.
It is an object of the invention to provide a construction which
simplifies the fixation of the lead cutters to the cutting member and which
is better adapted to mass production.
~ccording to the invention, there is provided a shaving apparatus
having a circular shear plate provided with hair-entrance apertures a-nd a cut-
ting unit associated with and rotatable relative to the shear plate, the cutting
unit comprising a cutting member having a circular central body, cutters
extending from the circumference of the central body toward the shear plate,
lead cutters respectively associated with and movable relative to *he cutters,
each lead cutter, with reference to the direction of rotation of the cutting
unit, being positioned in front of its associated cutters, respective connecting
arms extending from the lead cutters to the central body of the cutting member,
and a coupling piece separate from the cutting member and the connecting arms
for securing the connecting arms to the central body.
The coupling piece may be provided with substantially radial spokes~
the inner end of the connecting arm extending from a lead cutter being clamped
between the central body of the cutting member and a radial spoke.
A radial spoke may extend near a lead cutter and may constitute a
,~,. ~ - 1-
stop limiting the moYement of the lead cutter.
The radial spokes may extend beyond the circum-ference oE the cutting
member, and may be interconnected by an annular portion of the coupling piece.
The coupling piece may be provided with resilient tabs, each having
a hook-shaped projection, and the cut~ing member may be formed with openings
correspondingly located wi-th respect to the resilient tabs, the latter extending
into the openings upon assembly of the coupling place and the cutting member to
thereby constitute a snapped connection between the couplillg piece and the cut-ting member.
The coupling piece may have a coupling opening Eor the drive of the
cutting un:it.
The inveTItion will be explained hereinaEter by means o~ a descr:iption
; of some embodiments shown in the Figures.
}'igure 1 shows an elevation of a shaving apparatus having three shear
plates.
Figure 2 shows the shaving apparatus of Figure 1 in side view and
partly in a cross-section takenon the line II-II in Figure 1.
Figure 3 shows a perspective view of the cutting member with coupling
piece, lead cutters and mass-inertia disc in disassembled condition.
Figure 4 shows a plan view of the parts shown in Figure 3, which
parts have been assembled to a cutting Ullit.
Figure 5 is a cross-section taken on line V-V in Figure 4.
Figure 6 is a similar plan view as in Figure 4 of a different embodi-
ment of the cutting unit.
Figures 7 and 8 illustrate the operation of a lead cutter.
Figure ~ is a plan view of a modification of a hair pulling member
consisting of lead cutters, connecting arms and a central plate-shaped portion.
--2--
,
" . . : :
.. : : , ... . .
3~7
The shaving apparatus i.n accordance with Figures 1 and 2 comprises
a housing 1, of which a part takes the form of a shear-plate holder 2 fGr ~hree
shear plates 3. The shear plates 3 have hair-entrance apertures 4.
As is shown in the partial cross-section of Figure 2, a cutting unit
5 is situated on the inner side of a shear plate 3, which unit for the sake of
clarity is shown schematically, but is shown in detail and on an enlarged scale
in Figures 3 through 5.
The cutting unit 5 is coupled to the electric motor 10 by means of
the hollow spindle 6 (Figure 2), the gear wheels 7 and 8 and the spindle 9, so
,~
.
.~
. , ~ . , ,: .
3~
that the cutting unit is rotatable relative to the associated shear plate 3.
The gear wheel 7 is rotatably journalled on a pin 11 which is fixed in a mount-
ing plate 12. The gear ~heel 7 has a recess 13, which is closed by a cover
plate 1~. This cavity accommodates the flange 15 at the end of the hollow
spindle 6. By giving the flange 15 a non-round, for example square, shape and
shaping the recess 13 accordingly, a coupling is obtained :Eor the transmission
of the rotary movement of the gear wheel 7 to the spindle 6. The spring 16,
which for the greater part is situated in the hollow spindle 6 and is tensioned
between the hollow spindle 6 and the gear wheel 7, exerts a force on the spindle
6 in the direction of the cutting unit 5. As the cylindrical portion 17 of
tlle spindle 6 bears against the cutting unit 5 tll:is :eorce is exerted on the
cLItting unit and v:ia the cuttor ull:it 011 tllo shear plate 3, so tllcLt the she,lr
plate is pressed against the shear plate holder 2 with the edge 18. As a result
of external forces, as may for example occur during use of the shaving apparatus,
the shear plate 3 together with the cutting unit 5 and the spindle 6 can be
pressed inwards against the action of the spring 16.
The coupling for the transmission of the rotary movement between the
spindle 6 and the cutting unit 5 is obtained in that the spindle 6 has an end
19 of substantially rectangular-cross-section. This end 19 is situated in a
corresponding coupling opening 20 o:E the cutting unit 5.
The coupling to the electric motor 10 as described in -the Eoregoing
is identical for the three cutting units of the apparatus in accordance with
~igures 1 and 2, three gear ~heels 7 being in engagement-with a single centrally
disposed gear wheel 8 on the motor spindle 9.
The cutting unit 5 comprises a cutting member 21, a hair-pulling
member 22 with lead cutters 23, a coupling piece 2~ and a mass-inertia body
25 and these components are shown in perspective and in disassembled condition
- ~.,'
.
.
' :,' ~ :" " ', ' '
~8~37
in Figure 3.
The mass-inertia bod~, i.e. the annular disc 25, has a central open-
ing 26 and three cut-outs 27 on the inside.
The cutting member 21 is substantially constituted by a central body
28 which is provided with cutters 29 at the circumference. In a similar way
as the mass-inertia body 25, the central body has a central opening 30 and
three cut-outs 31.
The hair-pulling member 22 comprises a central plate-shaped portion
32 to which the lead cutters 23 are connected by m0ans of the connecting arms
33. The central plate-shaped portion 32 also has a central opening 34 and
three cut-outs 35.
The coupling piece 2~ comprises a cylindrical portion 36 with a
partition 37 and a 1ange 38. Ln the part~tion 37 the coupling opening 20 is
formed for the coupling to the hollow spindle 6. From the flange 38 the spokes
39 extend in a substantially radial direction. These spokes 39 are provided
with a cam 40. 0wing to the cut-outs 41 in the c~lindrical portion 36 the
resilient tabs 42 are formed, which at the ends are provided with hook-shaped
projections 43. On the out-side of the cylindrical portion 36 three ridges
44 are disposed.
I'he cutting member 21, the hair-pulling member 22 with the lead
cutters 23, and the mass-inertia body 25 can simply be assembled to a cutting
unit 5 with the aid of the coupling piece 24. For this purpose the mass-inertia
hody 25, the cutting member 21 and the hair-pulling member are stacked onto
each other in the se~uence shown in Figure 3, the central openings 26, 30 and
34 as well as the cut-outs 27, 31 and 35 then being coincident. The cylindrical
portion 36 of the coupling piece 2~ is passed through the central openings 26,
30, 34, the hook-shaped projections 43 moving im~ards in a radial direction.
-- 5 --
.
' :. .. ' , , ~:.
. .
;:.
.. : , .,: : , , ~, . .
,, ,.. , ... . . . :
37
The ridges 44 then engage with the cut-outs 279 31, 35, so that the components
21, 22, 24 and 25 cannot rotate relative to each ot'her. The hook-shaped
projections 43 snap behind the mass-inertia body 25, so that the components
: 21, 22, 24 and 25 are Eixed to each other. The snapped connection w,ith the
aid of the hook-shaped projections 43 on the resilient tabs 42 also simplifies
disassembly of the cutting unit 5.
,' In th.e assembled condition of the cutting unit 5 (Figures 4 and 5) the
lead cutters 23 engage ~ith the cutters 29. The end of the connecti.ng arm 33
o-E a lead cutter 23 uhich adjoins the central plate-shaped portion 32 is located
between the cam 40 of a spoke 39 and the central body 28 of the cutting member
21. The coupling piece 2~ has been dimerlsioned so that in the assembled condi-
tion of the cutting unit 4 the spokes exhibit a slight elasti.c t'lexure a.s a
result oE which the end of the colmecting arm 33 is clamped between the cam 40
and the central body 28. As a result of the elastic properties of the non-
clamped portion of the connecting arm 33, the lead cutter 23 is movable relative
to the associated cutter 29.
The end 45 of a spoke 39 is disposed near a connecting arm 33
which adjoins the connecting arm which is clamped in position by the cam 40 of
the same spoke 39. The end ~5 constitutes a stop for said adjacent connecting
arm and thus limits the rnovement o:E the lead cutter conrlected to said arm.
Obviously, it is also possible to design the spokes in such a way that one spoke
serves for retention and as stop for the same connecting arm.
The elastic properties of a connecting arm 33 are inter alia
dependent on the location of clamping of the end which adjoins the central plate-
shaped portion 32, i.e. the location where the cam 4Q engages with the connect-
ing arm 33. The elastic properties of a connecting arm can be determined
simply yet accurately by the shape and the dimensions of the coupling piece 2~.
:: - 6 -
;: ~!, ' ' . ~ ~ ' .
~$~37
.....
The coupling piece is preferably~manufactured from a plastic.
In the embodiment of Figure 6, which shows a plan view in accordance
with Figure 4, the spokes 46 extend beyond the circumference of the cutting
member. ~uring assembly or disassembly the cutting unit can then be held by
the ends of the spokes, so that the risk of damage ~o the other parts is reduced.
The spokes are interconnected by an annular member 47 so as to increase the
strength and rigidity of the coupling piece 24. The space which is left be-
tween the spokes, ensures that the removal of hair-cuttings from the vicinity
of the cutting unit is impeded to the least possible extent.
Figures 7 and 8 schematlcally show a side view of a part of the
cutting unit 5 in accordance with Figures 3 through 5 and a part of the shear
plate 3 and serve to illustrate the operation of the lead cutters.
As is shown in Figures 7 and 8 the lead cutter 23 engages with the
guide wall ~8 of the cutter 29 which wall is inclined relative to the shear
plate 3. When a hair 49 is caught in a hair-entrance aperture 4, said hair will
soon come into contact with the sharp edge 50 of the lead cutter 23 at the
location A o~ing to the rotary movement of the cutter 29 and the lead cutter
23, The sharp edge 50 i5 such that it will sllghtly penetrate the hair 49, but
without cutting off the hair. The reaction force which is exerted on the lead
cutter 23 by the hair 49 may be directed oppositely to the direction oE movement
P. This force will be encountered by the component Nl of the normal force N
which is exerted on the lead cutter 23 by the wall 48 of the cutter 29. (Figure
7~. For the sake of simplicity the slight frictional forces between the lead
cutter 23 and the cutter 49 have been neglected. The component N2 of the
normal force N will cause the lead cutter 23 to slide along the wall 48. The
angle ~ between the wall 48 and the wall 53 of cutter 29 which engages with the
shear plate 3 should be smaller than 90.
~ 7
Owing to inter alia the natural elasticity of the skin the hair ~9
will be moved along by the lead cutter 23 until the cutting edge 51 of the
cutter 29 has reached the hair at a location B (Figure 8). Subsequently, the
hair will be cut by cooperation of the shear plate 3 and the cutter 29. Thus,
a part of the hair 49 is cut off ~hich is longer than ~he part which would be
~ cut off without lead cutter by a length equal to the distance between A and B,
- so that a better shaving result is obtained.
~ s is evident from Figure 8 the point 52 of the connecting arm 33
has not yet reached the end 45 of the spoke 39 in this position of the lead
cutter 23. Ilowever, owing the inertial forces there is a rlsk that the lead
cutter 23 moves $urther in the direction away from the shear plate 3, in which
case the end 45 unctions as a stop which limits the movement of the connecting
arm 33 and thus o the lead cutter.
In the embodiment described ln the Eoregoing the lead cutters 23
are parts of a hair-pulling member 23. ~lowever, the coupling piece may also be
employed for the fixation o-f separate lead cutters to the cutting member.
If the lead cutters constitute a part of a hair-pulling member with
a central plate-shaped bcdy, the coupling piece may also engage with said
central plate-shaped body by clamping.
Instead of by a snapped connection the coupling piece may also be
$ixed to the cutting member in a different manner, for example by welding,
screwing or glueing.
Generally, the use o$ lead cutters ~ill impose llmits on the speed
of rotation of the cutting unit. Since in hair-cutting the amount of kinetic
energy of the cutting unit is an important -factor, the operation of the apparatus
may be improved in some cases by increasing its mass, for example, by means of
an additional mass-inertia body 25.
- 8 --
:,'
.:: . .
However, the coupling piece can also be made so heavy that an
additional mass-inertia body is not necessary.
Figure 9 concerns a hair plllling member 22 which in accordance with
the embodiment described above consists of lead cutters 23, connecting arms 33
and a central plate-shaped portion 32 having a central opening 34 and three
recesses 35 in its inner periphery. Three radially inwardly directed connection
tabs 54 are located in the recesses 35. These connection tabs 54 are thus
dimensioned that when assembling haîr pulling member 22 and coupling piece 24
the connection tabs 54 are slightly bent out of the plane of the central plate-
shaped portion 32~ The ends of the connection tabs 54 scrape thereby over the
ridges 44 (Figure 3) of t.he coupling piece 24. In the assembled position the
connection tabs 54 rest with a small elastic tension against the ribs 44 so that
the hair pulling member 22 and the coupling piece 24 in a simple way are saEely
secured together.
The central plate-shaped portion 32 is also provided with positioning
tabs 55 ~lhich are bent out of the plane of the central plate-shaped portion.
These positioning tabs 55 bridge the connection tabs 54 and serve to position
the hair pulling member 22 in relation to the cutting member 21. In the assem-
bled position of both parts the positioning tabs 55 are located in the cu~-outs
31 ~Figure 3~ of the cutting member 21 and thus define exactly the position
oE the hair pulling n~ember 22 in relation to the cutting member 21. For the
sake of clarity an unbent positioning tab 55' stretched out in the plane o:E
the central plate-shaped portion 32 is indicated in Figure 9 with dotted lines.
. : :
