U.S. patent number 3,648,367 [Application Number 04/849,273] was granted by the patent office on 1972-03-14 for cutterhead for electric dry shaver.
This patent grant is currently assigned to Sperry Rand Corporation. Invention is credited to Robert J. Tolmie.
United States Patent |
3,648,367 |
Tolmie |
March 14, 1972 |
CUTTERHEAD FOR ELECTRIC DRY SHAVER
Abstract
A cutterhead for an electric dry shaver which includes a
stationary outer cutter having a plurality of hair reception slots
and a movable inner cutter having a plurality of cutter teeth
wherein the cutter teeth are provided with buffed surfaces adjacent
the hair entry portions of the hair reception slots in the outer
cutter.
Inventors: |
Tolmie; Robert J. (Fairfield,
CT) |
Assignee: |
Sperry Rand Corporation (New
York, NY)
|
Family
ID: |
25305453 |
Appl.
No.: |
04/849,273 |
Filed: |
August 4, 1969 |
Current U.S.
Class: |
30/43.6;
30/43.92; 30/346.51 |
Current CPC
Class: |
B26B
19/042 (20130101) |
Current International
Class: |
B26B
19/04 (20060101); B26b 019/04 () |
Field of
Search: |
;30/43.6,43.4,43.91,43.92,346.51 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: McGehee; Travis S.
Assistant Examiner: Ramsey; K. J.
Claims
I claim:
1. An inner cutter adapted for movement within an outer cutter of
an electric dry shaver cutterhead assembly having a feeding area,
said inner cutter comprising a body portion, a plurality of cutter
teeth formed on said body portion, each of said cutter teeth
provided with at least one cutting edge for shearing hair bristles
fed thereto by the outer cutter, said teeth respectively further
including an arcuately shaped edge portion adjacent the feeding
area, the arcuately shaped edge portion of each tooth merging with
the cutting edge of said cutter tooth and adapted to move hair
bristles away from the cutting edge of said cutter tooth.
2. The device of claim 1 wherein the body portion comprises an
elongated body member of rectangular cross section, said cutter
teeth extending transversely of a top surface of the body
portion.
3. The device of claim 2 wherein said cutter teeth are
substantially rectangular and are provided with at least two spaced
and parallel cutting edges and a pair of said arcuately shaped edge
portions.
4. The device of claim 3 wherein said arcuately shaped edge
portions are adapted to move hair bristles away from the cutting
edges of the outer cutter at a predetermined shearing position of
said inner cutter.
5. The device of claim 1 wherein said inner cutter is adapted for
rotation within the outer cutter, a plurality of arms formed on
said body portion, and said cutter teeth being formed on the ends
of said arms.
6. The device of claim 5 wherein said teeth are provided with at
least two cutting edges and a pair of arcuately shaped edge
portions.
Description
BACKGROUND OF INVENTION
This invention relates to new and useful improvements in electric
dry shavers and more particularly to the cutterheads thereof.
The cutterheads of most known electric dry shavers include a
movable inner cutter disposed within a stationary outer cutter and
which cutters are arranged in mutual cutting cooperation. The outer
cutter is provided with a plurality of hair reception slots or
apertures which extend across the top of the outer cutter and into
the sides thereof. The inner cutter is formed with teeth having
sharpened edges for shaving hair bristles that enter the hair
reception slots in the sides of the outer cutter as the shaver is
manually moved over the face of the user.
In certain cutterheads the inner cutter is adapted for
reciprocating movement within the outer cutter in a linear path
defined by drive means provided in the shaver casing and in certain
other shavers the inner cutter is mounted for rotation within the
outer cutter. In electric dry shavers of the latter types in
addition to the hair bristles being combed into the cutterhead,
portions of the skin adjacent the base of the hair bristles are
also pressed into the hair reception slots and into contact with
the movable inner cutter. The teeth of these known inner cutters
have usually been provided with sharp right angular shaped corner
portions which are positioned adjacent the hair entry area in the
shaver reception slots in the sides of the outer cutter. It has
been found that these corner portions tend to pinch the skin prior
to the hair bristles being moved into shearing position with the
cutting or shearing portions at the top surface of the inner and
outer cutters.
In the past various means have been used to counteract and lessen
any irritating effects that result from skin entering the
cutterhead. In some shavers means are provided adjacent the outer
cutter to tension the skin in advance of entry of the hair into the
cutterhead and in others the corners of the inner cutter are
beveled to provide additional space between the corners of the
inner cutter teeth and the hair reception slots in the outer
cutter. Although these devices have met with varying success and
acceptance discomfort is likely to occur when the skin contacts the
inner cutter or if a hair bristle is not sheared correctly.
It is an object of this invention to provide a novel cutterhead for
an electric dry shaver.
Another object is to provide a novel inner cutter for an electric
dry shaver.
A still further object is to provide a novel inner cutter which is
formed with a sharp cutting edge for cutting hair bristles closer
to the skin and which inner cutter is provided with novel means
effective to substantially reduce any discomforting effects when
skin is combed into the cutterhead.
SUMMARY OF THE INVENTION
The present invention contemplates a novel inner cutter for an
electric dry shaver cutterhead. In one embodiment the cutterhead
comprises an elongated inner and outer cutter. The outer cutter
includes a plurality of transverse hair reception slots. The inner
cutter is mounted for reciprocating movement within the outer
cutter and has a plurality of transverse cutter teeth wherein the
inner and outer corners of the teeth adjacent the hair entry areas
of the slots in the outer cutter are buffed to engage and prevent
skin at said entry area from entering the cutting portions of the
inner and outer cutters in operation of the shaver.
The above and other objects and advantages of the present invention
will appear more fully herein after from a consideration of the
detailed description which follows taken together with the
accompanying drawings where two embodiments of the invention are
illustrated.
DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a fragmentary partly cross sectional elevational view of
an electric dry shaver taken through a cutterhead unit
incorporating the present invention;
FIG. 2 is a plan view of one end of the cutterhead unit of FIG.
1;
FIG. 3 is a sectional view taken on the line 3--3 of FIG. 2;
FIG. 4 is a perspective fragmentary view of the end portion of the
inner cutter of the cutterhead unit;
FIG. 5 is an enlarged sectional view taken on the line 5--5 of FIG.
3;
FIG. 6 is a plan view of the enlarged portion of the cutterhead
unit of FIG. 5;
FIG. 7 illustrates another embodiment of the present invention
incorporated in a rotary-type cutterhead; and
FIG. 8 is a fragmentary perspective view of a portion of the inner
cutter of FIG. 7.
DETAILED DESCRIPTION
Referring now to the drawings for a more detailed description of
the present invention an upper portion of shaver casing is
generally indicated by the reference numeral 10 in FIG. 1. A
cutterhead receptacle 11 is provided in casing 10 and in which
receptacle 11 is disposed a cutterhead assembly 12. Cutterhead
assembly 12 is of type construction which includes at least one
cutterhead unit 14 and which unit comprises a stationary outer
cutter 15 in which is disposed a movable inner cutter 16. Outer
cutter 15 comprises an elongated inverted U-shaped metal member
having a bight portion 18 and spaced depending sidewalls 19 (FIG.
3). The lower marginal portions of sidewall 19 are rigidly secured
to the arms of an elongated U-shaped base spacer partially shown in
FIG. 3 which is seated on a baseplate 21 (FIGS. 1 and 3) in a
conventional manner.
Inner cutter 16 comprises an open-ended elongated metal member
substantially rectangular in transverse cross section (FIG. 3)
maintained in cutting cooperation with outer cutter 15 against the
underside of bight portion 18 in a known manner, as for example by
a leaf spring 24 (FIGS. 1 and 3). Leaf spring 24 is provided with
arms 25 secured to the base of inner cutter 16 and with a central
loop portion 27 seated on a drive arm 28. Drive arm 28 extends from
a motor indicated by reference numeral 29 in FIG. 1 disposed in
shaver casing 10 through aligned openings in casing 10, a hair
stopper pad 30 and in cutterhead 14 to engage loop 27 and move
inner cutter 15 in a linear reciprocatory path upon operation of
motor 29.
Bight portion 18 of outer cutter 15 is provided with two rows of
hair reception slots 31 at each side of a longitudinal channel 38.
Each row of a pair of rows of slots 31 is separated by a
longitudinally extending rib 33 (FIGS. 2 and 3). The top surface
(FIG. 3) of inner cutter 16 engages the underside of bight portion
18 of outer cutter 15 and is provided with a longitudinally
extending channel 35 in which is disposed the corresponding channel
32 in outer cutter 16. A pair of rows of rectangular-shaped cutter
teeth 36 are formed in inner cutter 15 with one row of teeth 36
formed at each side of channel 35. Each tooth 36 is thereby
arranged to extend transversely of outer cutter 16 beneath rib 33 a
distance of a pair of hair reception slots 31.
In FIGS. 5 and 6 are shown the side edges 37 and 38 respectively of
each rectangular tooth 36 which are formed to a predetermined
degree of sharpness. Edges 37 and 38 are to shear hair bristles (as
for example diagrammatically indicated at A, B and C in FIG. 6) as
the edges 37 and 38 thereof pass bottom edge 40 of slots 31 when
the hair bristles are combed through the entry areas indicated at
41 in FIGS. 3, 5 and 6 in the outer cutter 15 and as inner cutter
15 is reciprocated by drive arm 28 in the direction indicated by
the arrows X and Y in FIG. 5.
In previous cutterheads of the general type described, the
remaining sides or the corners of the teeth of the inner cutter
have been formed at a right angle. It has been found that as a
result any hair or skin pressed into the cutterhead is engaged and
pinched by these corners as the butting edges 37 and 38, for
example, engaged the bottom edge 40 of the hair reception slot in
the outer cutter. As mentioned, it is an object of the present
invention to provide a cutter of increased cutting efficiency and
which cutter results in less irritation and discomfort to a user.
In accordance with the present invention, the corners 42 and 44 of
each tooth 36 are buffed to present curved surfaces adjacent the
hair entry areas 41.
In operation of the described cutterhead unit 14, as inner cutter
16 thereof travels in the linear path indicated by arrows X and Y
in FIG. 5, any hair bristles not contacting a cutting edge 37 or 38
as for example hair bristle B or C FIG. 6 are engaged by rounded
corner 42 or 44 and pushed aside as the teeth 36 pass beneath edges
40 of slots 31. In this manner only the hair bristles (such as
bristle A) positioned at a cutting edge 37 or 38 are sheared, the
hair bristles (such as bristles B and C) are moved away from the
shearing edges 37 or 38 of the outer cutter at a predetermined
position of the inner cutter.
In FIGS. 7 and 8 a further embodiment of the present invention is
shown incorporated in a rotary type cutterhead generally indicated
by the reference numeral 48. Cutterhead 48 is of a usual type
well-known in the art and comprises a circular metal outer cutter
49 (partially shown in FIG. 7) having hair reception slots 50 in
the top surface thereof. An inner cutter 51 mounted in a suitable
manner (not shown) for rotation within outer cutter 49 and is
provided with a plurality of arms 52 having cutting teeth 53. In
accordance with the present invention the corners 54 of teeth 53
are buffed. As inner cutter 51 is rotated the buffed corners 54
operate in a manner similar to the previously described buffed
corners 42 and 44 of cutterhead unit 12 (FIGS. 5 and 6) as hair
enters outer cutter 48 and insures that only hair bristles at the
cutting edge 55 is sheared.
It will be apparent from the foregoing description that novel
cutterhead unit has many advantages in use. The cutting edges, as
for example edges 37, 38 or 55 of an inner cutter may be formed to
a greater degree of sharpness without discomfort to the user since
the buffed corners of the cutter teeth displace the hair bristles
and skin in such a manner that only the hair to be cut is
positioned at the cutting edges. The elimination of the sharp
corners of the cutter teeth further substantially lessen any
pinching of the skin by the corners and allows for cutter bars of
greater length, if desired, since the combing or entry area between
the sides of inner cutter 16 and the hair reception slots 31 can be
lessened.
It is to be expressly understood that the present invention is not
limited to the embodiments illustrated and described. Various
changes can be made in the design and arrangement of parts without
departing from the spirit and scope of the invention, as the same
will now be understood by those skilled in the art.
* * * * *