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Патент USA US3047958

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Aug?’ 7, 1962
Filed April 8, 1959
JbhlzF Wahl
0W6 ,, %
United States Patent 0
Patented Aug. 7, 1962
Referring now to FIGS. 1, 2 and 3 of the drawings, one
embodiment of a drive ?nger constructed according to
John F. Wahl, Sterling, Ill., assignor to Wahl Clipper
Corporation, Sterling, III., a corporation of Illinois
Filed Apr. 8, 1959, Ser. No. 804,940
the reference numeral 10. This drive ?nger may be
3 Claims. (Cl. 30-210)
This invention relates to a vibrating motor and more
particularly to a drive ?nger for a vibrating motor used
in electric hair cutters.
the principles of this invention is indicated generally by
formed from unitary, ?at, thin, resilient, sheet material,
usually metal, and before forming may be substantially
T-shaped, although that shape is not critical, and others
are contemplated. For example, an initial rectangular
shape properly slotted would be quite practical. As un
10 derstood in the art, ?nger 10 is mounted to transmit vi
The present subject matter is disclosed but not claimed
bratory motion in the directions indicated by the arrows
in my prior co-pending application for Electromagnetic
Vibratory Unit, Serial No. 734,605, ?led May 12, 1958,
A in FIG. 1 from a vibratory armature 20 to a movable
blade 32 (FIG. 2) of an electric hair cutter.
Drive ?nger 10, in this particular embodiment, in
Electric hair cutting instruments, such as hair clippers, 15 cludes an elongated stem or arm portion 12, a base por
tion 16 and oppositely projecting arm portions 14—14.
which are powered by electromagnetic vibrating motors
which issued as Patent No. 2,967,253 on January 3, 1961.
have drive elements or ?ngers which are connected be
tween the free end of the motor armature and the mov
able cutting blade to transmit the vibrational movement
of the armature to the movable cutting blade and cause
it to oscillate.
In many instruments of this kind, the drive ?ngers
have other functions besides that of simply transmitting
As shown by its shape, the cross sections of the stem or
arm portion 12 transverse to its direction of elongation
are straight and parallel to each other so that the drive
?nger is resilient to forces applied to it which are per
pendicular to its surface and rigid to forces applied to it
which are parallel to its surface.
In vibratory motors used in hair cutting instruments,
the armature vibrates, and since its thickness is not signi?
motion. For example, they are often made resilient in
a direction perpendicular to the plane of vibration of 25 cant, the armature may be described as vibrating in a
plane. Base portion 16 of stem or arm portion 12 of
the movable cutting blade so that the movable cutting
drive ?nger 10 is connected to vibrating armature 20 in
blade may be biased into the required bearing contact
such a way that stem portion 12 is resilient to forces
with the ?xed cutting blade to establish a desired cutting
applied to it which are perpendicular to the vibrating
relationship between the blades. "In addition, the drive ?n
gers may be made resilient in the direction of the vibra 30 plane of armature 20. Consequently stem portion 12
of drive ?nger 10 is rigid to forces applied to it in direc
tional motion of the movable cutting blade to permit
tions Parallel to the vibrating plane of the armature and
relative movement in that direction in order to in?uence
the behavior of the armature assembly under load and
no-load conditions, and particularly to prevent stalling
of the armature under severe cutting loads.
Although resilience in the above described direction
of vibration is often desirable, it must be accomplished
perpendicular to the direction of elongation of the stem
or arm portion. The above described resilience may be
35 used to provide the required cutting bias or tension be
tween the ?xed and movable cutting blades described
In addition, the rigidity of drive ?nger 10 in the direc
without appreciably affecting the path of the movable
tion described above permits stem or arm portion 12 to
cutting blade which must oscillate along a substantially
straight line to maintain proper relationship between the 40 withstand the large inertial forces produced by the rapid
vibratory motion of the armature and movable blade
blades. If this is not done, the ends of the movable
without bending or whipping, in a plane parallel to the
blade tend to whip and extend beyond the margins of the
vibratory plane of the armature, around its connection
?xed blade. This is likely to injure the skin of the user.
with the armature. The direction of these inertial forces
The desired resilience along only a straight line parallel
to the path of the vibrating movable blade is not easy 45 applied to drive ?nger 10 is indicated by arrows C in
FIG. 1.
to achieve in the drive ?nger since the free end of the
Stem portion 12 may be bent at 13 to control the mag
armature assembly vibrates rapidly, and general resilience
nitude and direction of the bias between the ?xed and
in the drive ?nger could cause the above described whip
movable blades, and this direction is indicated by arrows
ping action.
B in FIG. 2.
What is needed therefore and comprises the principal
As seen, base 16 may ‘be enlarged and provided with
object of this invention is a drive ?nger which is resilient
openings 18, so that drive ?nger 10 may be secured
in a plane perpendicular to the plane of movement of
?rmly to the free end of armature 20 ‘by any conven
the movable cutting blade and which permits resilient
relative movement between the armature and the mov
tional means such as screws or rivets 17, see FIG. 2.
able cutting blade only along a substantially straight line 55 The oppositely extending arm portions 14—14 dis
posed on the free end of stem portion 12 opposite to
which is parallel to the path followed by the movable
the base portion 16 project from a common central sec
cutting blade.
tion 22. Arm portions 14—14 are bent substantially
perpendicular to central section 22 to form a pair of
panying drawings and speci?cation wherein:
60 spaced parallel ?anges 24 which extend in a direction
parallel to the direction of elongation of the central sec
FIG. 1 is a perspective view showing the end of an
tion 22. Since these ?anges are also formed from the
armature with the drive ?nger attached and with arrows
These and other objects of this invention will become
more apparent when read in the light of the accom
indicating its resilience in a plane parallel to the plane of
same resilient sheet material, they will be resilient mainly
to forces applied to it which are perpendicular to their
FIG. 2 is an end elevational view, partly in section, 65 surface.
As seen in FIG. 1, this means they will be resilient
of a portion of the armature and drive ?nger with a mov
to forces parallel to the vibrating plane of armature 20,
able cutting blade attached, showing by means of arrows
see the arrows D in FIG. 3. The free ends 26 of ?anges
the resilience of the drive ?nger in a plane perpendicu
24 in this particular embodiment are bent toward each
lar to the vibrational plane of the movable cutting blade.
70 other in a plane parallel to the plane of the common
FIG. 3 is a sectional view on line 3—3 of FIG. 2.
vibrational movement of the armature.
FIG. 4 is a sectional view of a modi?ed drive ?nger
embodying the features of this invention.
central section 22.
These free ends are adapted to be
secured in suitable manner, as by molding, to plastic
3,047, 948
member 30 which engages movable cutting blade 32 of
the hair cutting instrument. As seen, movable blade
32 vibrates along a line or path parallel to the cutting
portion of ?xed blade 33.
This arrangement introduces a resilient between arma
ture 20 and movable cutting blade 32 in the vibratory
plane of the armature so that the operation of the vi
I claim:
1. In a hair cutting instrument having a ?xed blade,
a cooperating movable blade and a motor including a
vibratory armature having a free end spaced from said
movable blade; a drive ?nger of resilient sheet material
extending between said armature free end and said mov
able blade and connected rigidly to said free end and
brating motor under load and no-load conditions may be
to means rigidly engaging said movable blade, the por
optimized and armature stall under severe loads may be
tion of said drive ?nger adjacent said armature free end
eliminated. At the same time, since the length of the 10 having its width dimension parallel to the plane of arma
?anges 24 is small in comparison to the length of stem
portion 12, any pivoting movement of these ?anges
around an axis de?ned by their edge connection to cen
ture vibration whereby said portion is rigid to forces
parallel to said plane and resilient to forces normal to
said plane, said former characteristic effective to prevent
blade whipping and said latter characteristic effective to
tral section 22 will produce only insigni?cant deviations
from the straight line motion of the movable cutting
A modi?ed drive ?nger 40 is shown in ‘FIG. 4. This
drive ?nger may initially be T-shaped, but in this con
provide cutting bias ‘between said blades, the portion of
said drive ?nger adjacent said movable blade extending
from said ?rst portion and having a width dimension
lying in a plane generally perpendicular to said ?rst por
struction downwardly facing U-shaped ?anges 42 includ
tion and to the path of said movable blade whereby said
ing upwardly bent arms 14’—14' are formed on the ends 20 last portion is rigid to forces tending to twist same and
of common central section 44. The extreme ends 46
resilient to forces parallel to said path, said ‘former char
of ?anges 42 are bent toward each other in a plane par—
acteristic further effective to prevent blade whipping and
allel and closely adjacent to the plane of the common
said latter characteristic eifective to prevent motor stall
central section 44. Ends 46 are adapted to be con
when the instrument is subjected to heavy mechanical
nected to a plastic member (not shown) like that de 25 load.
scribed in connection with the form shown in FIGS. 1-3.
2. The combination of claim 1 wherein said last por
This modi?cation in which central section 44 is closely
adjacent to ends 46 of ?anges 42 is useful when space
limitations in a particular cutter forbid the employment
of the drive ?nger shown in FIG. 1 with the compara 30
tively large separation between common central section
22 of the arms 14-44 and ends 26 of ?anges 24.
tion comprises a pair of spaced ?anges having width di
mensions normal to forces parallel to the path of said
movable blade, the free ends of said ?anges rigidly se
cured to plastic means adapted to seat rigidly within a
recess in said blade.
3. The apparatus set forth in claim 2 wherein said
thermore, despite any space limitations which may be
?anges are U-shaped to increase the length thereof with
encountered, the overall length of ?anges 42 may be
out causing a corresponding increase in a dimension of
made equal to or greater than the length of ?anges 24 35 the drive ?nger.
in drive ?nger 10 so the modi?ed drive ?nger may be
References Cited in the ?le of this patent
used to provide any desired resilience between armature
20 and movable cutting blade 32 in planes parallel to the
vibrating plane of the armature.
The invention may be embodied in other forms with 40 1,596,294
N'orstrom ___________ __ Aug. 17, 1926
out departing from the spirit or essential characteristics
Kusnarowis __________ __ June 1, 1937
thereof as set forth in the claims, and the present em
bodiment is therefore to be considered as illustrative and
not restrictive, and it is intended to include all changes
which come within the scope and range of the claims.
Wahl ________________ __ Dec. 9,
Andis _______________ __ Dec. 8,
Andis et al. ___________ _._ Feb. 9,
Wahl et al. __________ __ Mar. 10,
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