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Publication numberUS3815232 A
Publication typeGrant
Publication dateJun 11, 1974
Filing dateFeb 9, 1973
Priority dateFeb 10, 1972
Also published asCA973346A1, DE2305680A1, DE2305680B2, DE2305680C3
Publication numberUS 3815232 A, US 3815232A, US-A-3815232, US3815232 A, US3815232A
InventorsLiska E
Original AssigneePayer Lux
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Shear foil for a dry shaver
US 3815232 A
Abstract
The invention relates to a shear foil for a dry shaver in which, for stiffening of the shear foil, the opening ratio of the shear holes arranged in one main area gradually decreases as compared to the opening ratio of the shear holes arranged in one of the border areas. In this, the measurement of the shear holes taken transversely to the moving direction of the cutting element carrier in the border area is kept equal or increased and only that measurement of the shear holes taken in the moving direction of the cutting element carrier is gradually decreased in the border area towards the edge of the shear foil as compared to the main area.
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Description  (OCR text may contain errors)

[ June 11, 1974 SHEAR FOIL FOR A DRY SHAVER [75] Inventor: Erich Liska, l-litzendorf, Austria [73] Assignee: Payer-Lux Eduard Payer, Graz,

Austria 22 Filed: Feb. 9, 1973 211 Appl. No.:330,928

[30] Foreign Application Priority Data Primary Examiner-Al Lawrence Smith Assistant Examiner-Gary L. Smith Attorney, Agent, or Firm-Browne, Beveridge, De- Grandi & Kline [5 7] ABSTRACT The invention relates to a shear foil for a dry shaver in Feb. 10. 1972 Austria 1070/72 which, for stiffening of the shear foil, the opening ratio of the shear holes arranged in one main area gradually [52] [1.8. CI. 30/346.5l, 30/346.61 decreases as compared to the opening ratio of the [51] Int. Cl B26b 19/04 shear holes arranged in one of the border areas. In [58] Field of Search 30/4391, 43.92, 346.51, this, the measurement of the shear holes taken trans- 30/346.6l versely to the moving direction of the cutting element carrier in the border area is kept equal or increased [56] References Cited and only that measurement of the shear holes taken in UNITED STATES PATENTS the moving direction of the cutting element carrier is 3 229 366 H1966 strezoff 30/346 5] X gradually decreased in the border area tovvards the 3:468:025 9/1969 Messin erIIIIEIIIIII..,. 30/3A6.5l edge Ofthe Shear as compared the mam area FOREIGN PATENTS OR APPLlCATlONS 21 C'aims 15 Drawing Figures 2.0!),746 ll/l97l Germany 30/134651 l r I l. v

\ J:' FW F PATENTEDJUH 1 1 ran SHEET 10F 7 FIG] SHEET 2 OF 7 PATENTEDJUH 1 1 m4 SHEEIRBF 7 PIC-3.6

minimum mm 31315232 SHEE! 7m 1 FIG. I5

5 3 .3 w: c c c c 3 Q. .3 Q C L c L 3 Q .3 J C L C L J 3 .3 -3 TTVT C OM jfi q #4] L C 3 r g C SHEAR FOIL FOR A DRY SHAVER The invention relates to a shear foil for a dry shaver.

In a known shear foil of this type, the stiffening of the border zone is effected solely by placing singly or staggering circular shear holes of equal size. It is further known in shear foils to stiffen the more heavily stressed border zones by gradually reducing the diameter of the circular shear holes towards the edge of the shear foil under retention of the screen size of the main area. in another known solution, it is suggested to retain the screen definition in the border zones in the moving di rection of the cutter element carrier and to gradually reduce the screen definition transverse to the moving direction of the cutter element carrier and the diameter of the circular shear holes towards the edge of the shear foil so that the width of the foil strips in the moving direction of the cutter element carrier remains the same and the width of the foil strips positioned transversely to the moving direction of the cutter element carrier gradually increases. The disadvantage of these known arrangements is that the shaving capacity in the border zone of the shear foil is considerably reduced if a fairly adequate stiffening of the border zones of the shear foil is to be achieved.

It is the object of the present invention to avoid this disadvantage of the known shear foils and to provide a shear foil in which optimum shaving capacity in the border zone is secured in spite of excellent stiffening.

According to the invention, a shear foil for a dry shaver with at least one shear head provided with a cutter element carrier movable under the shear foil comprises shear holes distributed in at least one part of the shear foil that part forming the shear head having one main area and at least one border area, the measurement of the shear holes in at least one border area taken transversely to the moving direction of the cutter element carrier, for stiffening the shear foil, being kept equal as compared to the corresponding measurement of the shear holes in the main area and merely the measurement of the shear holes in the border area taken in the moving direction of the cutter element carrier being progressively decreased towards the edge of the border area positioned in the moving direction of the cutter element carrier and removed from the main area.

According to another embodiment of the invention, a shear foil for a dry shaver with at least one shear head is provided with a cutter element carrier movable under the shear foil comprising shear holes distributed in at least one part of the shear foil that part forming the shear head having one main area and at least one border area, the measurement of the shear holes in at least one border area taken transversely to the moving direction of the cutter element carrier, for stiffening the shear foil, being increased towards the edge of the border area positioned in the moving cirection of the cutter element carrier and removed from the main area, and merely the messurement of the shear holes in the border area taken in the moving direction of the cutter element carrier being progressively decreased, as compared to the corresponding measurement of the shear holes in the main area, towards the edge of the border area positioned in the moving direction of the cutter element carrier and removed from the main area.

A further shear foil for a dry shaver according to the present invention is a shear foil with two shear heads combined to one double shear head, said double shear head being formed of one single shear foil provided with shear holes and at least one cutter element carrier movable under the shear foil arranged underneath it, comprising the shear foil having one main area and at least one border area adjacent the main area for each shear head, the shear holes being distributed in those areas, the measurement of the shear holes in at least one border area taken transversely to the moving direction of the cutter element carrier, for stiffening the shear foil, being kept equal as compared to the corresponding measurement of the shear holes in the main area and merely the measurement of the shear holes in the border area taken in the moving direction of the cutter element carrier being progressively decreased towards the edge of the border area positioned in the moving direction of the cutter element carrier and removed from the main area.

A further shear foil for a dry shaver according to the invention is a shear foil with two shear heads combined to one double shear head, said double shear head being formed of one single shear foil provided with shear holes and at least one cutter element carrier movable under the shear foil arranged underneath it, comprising the shear foil having one main area and at least one border area adjacent the main area for each shear head, the shear holes being distributed in those areas, the measurement of the shear holes in at least one border area taken transversely to the moving direction of the cutter element carrier, for stififening the shear foil, being increased towards the edge of the border area positioned in the moving direction of the cutter-element carrier and removed from the main area and merely the measurement of the shear holes in the border are taken in the moving direction of the cutter element carrier being progressively decreased towards the edge of the border area positioned in the moving direction of the cutter element carrier and removed from the main area.

The invention is based on the finding that the shear capacity in a hole area depends mainly upon the total length of the edge sections of the shear holes which are positioned transversely to the moving direction of the cutter element carrier and that, as a result, very good stiffening at very good shaving capacity can be achieved if only in the border area the size of the shear holes positioned in the moving direction of the cutter element carrier is gradually decreased towards the edge of the shear foil, while the size of the holes transversely to the moving direction of the cutter element carrier is retained equal or even increased towards the edge of the shear foil. In this way, the total length of the effective shearing edges is essentially retained or even increased, while very good stiffening is achieved.

It is of advantage in each of the embodiments of the invention previously indicated if at least part of the shear holes in the border area has the embodiment of slits positioned with their longitudinal axes transversely to the moving direction of the cutter element carrier.

It is further of advantage in each of the embodiments of the invention previously indicated if the slitshaped shear holes in the border area have a length of 0.0248

to 0.0323 inches and a width of 0.0217 to 0.0l38 inches.

It is further of advantage in each of the embodiments of the invention previously indicated if the shear holes are distributed according to a determined screen definition in at least one main area.

It is further of advantage in each of the embodiments of the invention previously indicated if the screen definition of the shear holes of the border ara measured transversely to the moving direction of the cutter element carrier is progressively increased as compared to the main area towards that edge of the border area positioned in the moving direction of the cutter element carrier and removed from the main area.

It is further of advantage in each of the embodiments of the invention previously indicated if the screen definition of the shear holes in the border area taken in the moving direction of the cutter element carrier is equal to the screen definition of the shear holes in the main area.

It is further of advantage in each of the embodiments of the invention previously indicated if the shear holes of adjacent hole rows are staggered, said hole rows being transversely positioned in the moving direction of the cutter element carrier and said staggering being effected at least in said border area transversely to the moving direction of the cutter element carrier.

In those embodiments in which the length of the shear holes in the border area increases as compared to the length of the shear holes in the main area, it is of advantage if the length of the slit-shaped shear holes in the border area axceeds the corresponding measurement of the shear holes in the main area taken transversely to the moving direction of the cutter element carrier by up to about 30 percent.

The invention is explained in detail by means of the drawing, as follows:

FIG. 1 is a view of a shear foil for a dry shaver partially in cross section,

FIG. 2 a plan view of a shear head with the shear foil according to the present invention,

FIG. 3 a plan view of a double shear head with the shear foil according to the present invention,

FIG. 4 a plan view of part of a shear foil according to the invention,

FIG. 5 and 6 details of a shear foil according to the invention and FIGS. 7 to 15 various arrangements of the shear holes in a shear foil according to the invention.

FIG. 1 shows a shear head 10 of a dry shaver with a shear head housing 11 provided with a window-like opening 12. A perforated shear foil 13 covers the window-like opening 12. Underneath the shear foil 13, a cutter element carrier 14 is movably arranged, with the moving direction of the cutter element carrier 14 symbolized by the double arrow F. By means of at least two bars 15, the shear foil 13 is secured to the shear head housing 11. This securing is effected so that the longitudinal edges of the shear foil can be inserted in the gap between the bars 15 and the walls of the shear head housing 11. The bars 15 are fixed to the shear head housing 11 by means of screws 16 piercing the shear foil 13 through the holes 9.

FIG. 2 shows the plan view of a shear head. The main area bears the reference number 3, the border areas the reference number 5. This figure further shows the screws 16 by means of which the shear foil 13 is fixed.

FIG. 3 shows a dry shaver with a double shear head. Two shear heads formed by one single shear foil 13 are visible. The shear foil 13 extends over two main areas 3 and the border areas 5. Between the two shear heads formed by one single shear foil 13, there are screws 17 provided for fixing the central part of shear foil 13.

FIG. 4 shows part of a shear foil 13 for a double shear head of a dry shaver in a spread-out state. The shear foil 13 therefore has two identical shear foil sections I and II positioned on either side of the central line 2. The drawing only shows the whole shear foil section I. Each one of these sections I and II thus forms a part of the shear foil comprising one main area and at least one border area, that part of the shear foil forming a shear head. Each shear foil section or part has a main area 3 in which the shear holes 4 are distributed in a certain screen definition and two border areas 5 in the present embodiment according to the invention in which, for stiffening the shear foil, the opening ratio of the shear holes 4 of the border area progressively decreases as compared to the corresponding measurement of the shear holes in the main area towards the edge of the border area positioned in the moving direction of the cutter element carrier and removed from the main area. Opening ratio is understood to mean the ratio of the total operating surface of the shear holes 4 to the remaining strip surface. In the center of the shear foil 13, there is a zone 6 free of shear holes. Free zone 6 is provided with recesses 7 for attachment of the shear foil 13 to a central part of the shear head by means of screws 17. The outer longitudinal edges of the shear foil are provided with free zones 8 without shear holes. In the drawing, only zone 8 of shear foil section I is shown. These zones are provided with recesses 9 for attachment of the border of the shear foil 13 on the edge of a shear head housing 11 by means of screws 16.

FIGS. 5 and 6 show details A and B of the shear foil 13 in one embodiment according to the invention. Identical parts bear the same reference numbers as in FIG. 4. According to the invention, excellent shaving capacity at very good stiffening of the border zone of the shear foil 13 is achieved by making the measurement Q of the shear holes 4 taken transversely to the moving direction F of the cutter element carrier 14 in the border areas 5 equal to the corresponding measurement Q of the shear holes 4 in the main area 3, while the measurement L taken in the moving direction F of the cutter element carrier 14 towards the edge of the border area 5 positioned in the moving direction F of the cutter element carrier 14 and removed from the main area gradually decreases as compared to the corresponding measurement L in the main area. This means that the measurement L gradually decreases from shear hole to shear hole in the border areas towards said edge of the border area 5.

In the embodiment of the shear foil 13 according to the invention shown in the drawing, at least part of the shear holes 4 in the border areas 5 has the form of slits positioned with their longitudinal axes transversely to the moving direction F of the cutter element carrier. An increase in stiffness of the border areas of the shear foil 13 can be achieved by gradually increasing the screen definition R positioned transversely to the moving direction F of the cutter element carrier in the order areas .Saswmar j th ssrse d fin n 9.

of the main area towards the edge of the border area 5 positioned in the direction of the cutter element carrier l4 and removed from the main area 3. From FIGS. 5 and 6 of the drawing, it is evident that the outermost screen definition R is essentially larger than the innermost screen definition RQ' of a border area 5. It is practical to keep the screen definition R positioned in the moving direction F of the cutter element carrier 14 in the border areas 5 of the shear foil according to the present invention equal to the screen definition of the main area. In this, the slit-shaped shear holes in the border area can have a length of 0.0248 to 0.0323 inches and a widthof 0.0217 to 0.0138 inches.

In FIG. 7, the border area 5 of a modified shear foil 13 which is provided with shearing holes 4 of generally rectangular form is illustrated. The width L of adjacent shear holes 4 taken transversely to the moving direction of the cutter element carrier decreases in the direction to the border as compared to the width L in the main area 3. In the direction to the border, each shear hole 4 in the border area 5 has the same width Q and the distances R between all adjacent openings 4 are equal.

In FIG. 8, the border area 5 of a further modified shear foil 13 is illustrated. In this embodiment, in the direction to the border, each shear hole 4 has the same width Q but the distances R between adjacent openings increase in the direction to the border.

FIG. 9 shows another embodiment of a shear foil 13 which has shear holes 4 of generally rectangular form. As indicated above, the width L of said holes extending transversely to the moving direction of the cutter element carrier decreases in the direction to the border. The distances R between adjacent openings are equal, but the width Qof adjacent openings increases in the direction to the border.

In FIG. 10, a further modified shear foil 13 is shown. As in the embodiment above, the width L of the shear holes 4 of the illustrated shear foil 13 transversely to the moving direction of the cutter element carrier decreases in the direction to the border. However, the measurement Q of the shear holes in said direction to the border and the distances R between adjacent openings increase in said direction.

FIG. 11 shows a further modified shear foil 13. The shear holes 4 of said shear foil 13 are arranged in rows which are staggered at a distance Y in respect to one another. The sizes and distances of the holes 4 correspond to the arrangement according to FIG. 7.

In FIGS. 12 to 14 further modifications of a shear foil 13, each of them provided with staggered rows of shear holes, are shown. The sizes and distances of the shear holes 4 substantially correspond to FIGS. 8 to 10. FIG. 12 further substantially corresponds to a part of the embodiment shown in FIGS. 5 and 6.

FIG. 15 shows a still further embodiment of the border area of a shear foil which has rows of holes 4 whose width extending transversely to the moving direction of the cutter element carrier decreases from hole to hole in the direction of the border. The distances Z and Z between the rows transversely to the moving direction of the cutter element carrier are of different size.

In all the FIGS. 4 to 15 the separation of the border area 5 from the main area 3 is indicated by means of the line 18-18. Adjacent the border area, there is the zone 8 free of holes.

Per se, it is quite immaterial in the present invention whether the dry shaver is provided with one hear head or with several shear heads. It is further immaterial whether the shear heads are formed by one shear foil or by several shear foils. Each shear head, however, has one main area and at least one border area in which areas the holes are distributed. It equally does not matter whether each shear head is provided with its own cutter element carrier or the cutter element carriers are connected to each other or combined with each other. By the same token, various embodiments of shear heads are to be considered as equal to the shear heads dealt with in the present application. The mode of separation of the shear heads in a double shear head is equally immaterial for the embodiment of the present invention, as the reinforcement of the shear foil at simultaneous improvement of the shaving capacity is secured according to the present invention by the embodiment of the shear foil according to the invention in each type of application and in each embodiment of the invention. A different arrangement of the shear holes in the sections I and II, on either side of the central line 2 or on a shear head itself is also possible.

The shape of the shear holes can be chosen arbitrarily.

In the figures, the progressive increase of the measurement Q is represented in an exaggerated manner to achieve a more lucid explanation. I

I claim:

1. Shear foil for a dry shaver with at least one shear head provided with a cutter element carrier movable under the shear foil comprising shear holes distributed in at least one part of the shear foil that part forming the shear head having one main area and at least one border area, the measurement of the shear holes in at least one border area taken transversely to the moving direction of the cutter element carrier, for stiffening the shear foil, being kept equal as compared to the corresponding measurement of the shear holes in the main area and merely the measurement of the shear holes in the border area taken in the moving direction of the cutter element carrier being progressively decreased towards the edge of the border area positioned in the moving direction of the cutter element carrier and removed from the main area.

2. Shear foil according to claim 1 comprising at least part of the shear holes in the border area having the embodiment of slits positioned with their longitudinal axes transversely to the moving direction of the cutter element carrier.

3. Shear foil according to claim 2 comprising the slit shaped shear holes in the border area having a length of 0.0248 to 0.0323 inches and a width of 0.0217 to 0.0138 inches.

4. Shear foil according to claim 1 comprising the shear holes being distributed according to a determined screen definition in at least one main area.

5. Shear foil according to claim 1 comprising the screen definition of the shear holes of the border area measured transversely to the moving direction of the cutter element carrier being progressively increased as compared to the main area towards that edge of the border area positioned in the moving direction of the cutter element carrier and removed from the main area.

6. Shear foil according to claim 1 comprising the screen definition of the shear holes in the border area taken in the moving direction of the cutter element carrier being equal to the screen definition of the shear holes in the main area.

7. Shear foil according to claim 1 comprising staggering the shear holes of adjacent hole rows, said hole rows being transversely positioned to the moving direction of the cutter element carrier, said staggering being effected at least in said border area transversely to the moving direction of the cutter element carrier.

8. Shear foil for a dry shaver with at least one shear head provided with a cutter element carrier movable under the shear foil comprising shear holes distributed in at least one part of the shear foil that part forming the shear head having one main area and at least one border area, the measurement of the shear holes in at least one border area taken transversely to the moving direction of the cutter element carrier, for stiffening the shear foil, being increased towards the edge of the border area positioned in the moving direction of the cutter element carrier and removed from the main area, and merely the measurement of the shear holes in the border area taken in the moving direction of the cutter element carrier being progressively decreased, as compared to the corresponding measurement of the shear holes in the main area, towards the edge of the border area positioned in the moving direction of the cutter element carrier and removed from the main area.

9. Shear foil according to claim 8 comprising at least part of the shear holes in the border area having the embodiment of slits positioned with their longitudinal axes transversely to the moving direction of the cutter element carrier.

10. Shear foil according to claim 9 comprising the slit-shaped shear holes in the border area having a length of 0.0248 to 0.0323 inches and a width of 0.0217 to 0.0138 inches.

11. Shear foil according to claim 9 comprising the length of the slit-shaped shear holes in the border area exceeding the corresponding measurement of the shear holes in the main area taken transversely to the moving direction of the cutter element carrier by up to about 30 percent.

12. Shear foil according to claim 8 comprising the screen definition of the shear holes of the border area measured transversely to the moving direction of the cutter element carrier being progressively increased as compared to the main area towards that edge of the border area positioned in the moving direction of the cutter element carrier and removed from the main area.

13. Shear foil according to claim 8 comprising the screen definition of the shear holes in the border area taken in the moving direction of the cutter element carrier being equal to the screen definition of the shear holes in the main area.

14. Shear foil according to claim 8 comprising staggering the shear holes of adjacent hole rows, said hole rows being transversely positioned to the moving direction of the cutter element carrier, said staggering being effected at least in said border area transversely to the moving direction of the cutter element carrier.

15. Shear foil according to claim 8 comprising the shear holes being distributed according to a determined screen definition in at least one main area.

16. Shear foil for a dry shaver with two shear heads combined to one double shear head, said double shear head being formed of one single shear foil provided with shear holes and at least one cutter element carrier movable under the shear foil arranged underneath it, comprising the shear foil having one main area and at least one border area adjacent the main area for each shear head, the shear holes being distributed in those areas, the measurement of the shear holes in at least one border area taken transversely to the moving direction of the cutter element carrier, for stiffening the shear foil, being kept equal as compared to the corresponding measurement of the shear holes in the main area and merely the measurement of the shear holes in the border area taken in the moving direction of the cutter element carrier being progressively decreased towards the edge of the border area positioned in the moving direction of the cutter element carrier and removed from the main area.

17. Shear foil according to claim 16 comprising the screen definition of the shear holes of the border area measured transversely to the moving direction of the cutter element carrier being progressively increased as compared to said main area towards that edge of the border area positioned in the moving direction of the cutter element carrier and removed from the main area.

l8. Shear foil according to claim 16 comprising staggering the shear holes of adjacent hole rows, said hole rows being transversely positioned to the moving direction of the cutter element carrier, said staggering being effected at least in said border area transversely to the moving direction of the cutter element carrier.

19. Shear foil for a dry shaver with two shear heads combined to one double shear head, said double shear head being formed of one single shear foil provided with shear holes and at least one cutter element carrier movable under the shear foil arranged underneath it, comprising the shear foil having one main area and at least one border area adjacent the main area for each shear head, the shear holes being distributed in those areas, the measurement of the shear holes in at least one border area taken transversely to the moving direction of the cutter element carrier, for stiffening the shear foil, being increased towards the edge of the border area positioned in the moving direction of the cutter element carrier and removed from the main area and merely the measurement of the shear holes in the border area taken in the moving direction of the cutter element carrier being progressively decreased towards the edge of the border area positioned in the moving direction of the cutter element carrier and removed from the main area.

20. Shear foil according to claim 19 comprising the screen definition of the shear holes of the border area measured transversely to, the moving direction of the cutter element carrier being progressively increased as compared to said main area towards that edge of the border area positioned in the moving direction of the cutter element carrier and removed from the main' area.

21. Shear foil according to claim 19 comprising staggering the shear holes of adjacent hole rows, said hole rows being transversely positioned to the moving direction of the cutter element carrier, said staggering being effected at least in said border area transversely to the moving direction of the cutter element carrier.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3229366 *Sep 19, 1963Jan 18, 1966Bogoia StrezoffDry shaving device
US3468025 *Sep 9, 1966Sep 23, 1969Braun AgFlexible screen foil
DE2019746A1 *Apr 23, 1970Nov 4, 1971Braun AgTrockenrasierapparat
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3916522 *Sep 20, 1974Nov 4, 1975Matsushita Electric Works LtdOuter blade for reciprocal type electric shaver
US3967373 *Mar 20, 1974Jul 6, 1976Matsushita Electric Works, Ltd.Outer blade for electric shaver
US4170822 *Nov 7, 1977Oct 16, 1979U.S. Philips CorporationDry shaving apparatus
US4926552 *Dec 30, 1988May 22, 1990Matsushita Electric Works, Ltd.Cutting head for reciprocatory-type dry shavers
US5088200 *Oct 11, 1990Feb 18, 1992Andis CompanyHair trimmer having a low-friction rotary drive
US5325590 *Mar 9, 1993Jul 5, 1994Andis CompanyFor use with a cutting head assembly
US5867908 *May 15, 1997Feb 9, 1999U.S. Philips CorporationShaving apparatus
US8806763 *Jan 16, 2013Aug 19, 2014Panasonic CorporationElectric shaver
US20130125401 *Jan 16, 2013May 23, 2013Panasonic CorporationElectric shaver
EP1568450A1 *Feb 25, 2005Aug 31, 2005Izumi Products CompanyReciprocating electric shaver, inner cutter and inner cutter manufacturing method
EP1685931A1 *Nov 10, 2004Aug 2, 2006Matsushita Electric Works, Ltd.Electric razor
Classifications
U.S. Classification30/346.51
International ClassificationB26B19/38
Cooperative ClassificationB26B19/384
European ClassificationB26B19/38B