Blade for a hair-cutting device

Abstract

A blade for a hair-cutting device having at least one longitudinal edge which comprises cutting portions and noncutting portions alternately spaced along the length of the said longitudinal edge, the blade having apertures therein to enable it to be adjustably secured to a hair-cutting device.

Description

This invention relates to a blade for a hair-cutting device.

More particularly, this invention relates to a blade for a hair-cutting device which may be passed through the hair of the user with a motion similar to a combing motion, so that the blade engages and shortens the hair of the user.

In prior proposed hair-cutting devices of this type, the blades are similar to razor blades and have a continuous cutting edge on each of their two longitudinal edges. As a result, prior proposed hair-cutting devices having razorlike blades can only be used for shortening the hair and cannot, in general, be used merely for hair thinning. However, since it is desirable to be able to thin the hair to produce correct cutting and a desired style, the prior art hair-cutting devices are no replacement for regular visits to a hair dresser if a desirable hair style is to be maintained. Thus persons who utilize the known hair-cutting devices must visit a hair dresser between the times when they utilize their hair-cutting devices if a desirable hair style is to be maintained.

It is an object of the present invention to provide a hair-cutting device which is capable of thinning the hair of a user.

According to this invention, there is provided a hair-cutting device having a blade that may be passed through the hair of the user so that the hair engages both noncutting portions of the blade edge and cutting portions. The length to which hair may be determined by the length of the teeth provided on the hair-cutting device and protruding beyond the longitudinal edge of the blade. Thus, in utilizing a hair-cutting device provided with a blade in accordance with the present invention, a genuine thinning of the hair may be achieved.

Conveniently, the noncutting portions of the longitudinal edge of the blade may be recessed relative to the cutting portions thereof, so that the cutting portions protrude beyond the noncutting portions. However, the blade may be manufactured so that only portions of one longitudinal edge of the blade are ground to form cutting portions, the noncutting portions remaining unground.

Preferably, the non-cutting portions are uniformly spaced along a single longitudinal edge of the blade, so that when the hair cutting device is used, the hair is uniformly thinned out.

Conveniently, a blade in accordance with the invention may have noncutting portions only on one longitudinal edge. Another longitudinal edge of the blade may be provided with an uninterrupted cutting edge. In utilizing a hair-cutting device provided with such a blade, the blade may be positioned so that the hair of the user engages one longitudinal edge to provide a thinning effect. The blade may be inverted so that the uninterrupted cutting edge contacts the hair of the user to provide a cutting effect.

In a further embodiment of the invention, two opposed longitudinal edges of a blade may each have cutting portions and noncutting portions, the widths of the cutting portions or noncutting portions on one longitudinal edge of the blade differing from the widths of the corresponding cutting or noncutting portions on the other longitudinal edge of the blade. In utilizing such a blade in a hair-cutting device, it can be seen that various degrees of thinning can be selected by reversing the position of the blade in the hair-cutting device.

Conveniently, one or more apertures may be provided in the blade adapted to cooperate with a correspondingly shaped projection or projections provided on a hair cutting device to locate the blade in the device. Advantageously, there may be two apertures provided in the blade, each being provided with an incision which extends from the aperture. Each aperture can then engage a complementarily shaped protrusion provided on the hair cutting device.

Conveniently, each aperture provided in the blade has the shape of an elongated slot. The blade defines a plurality of incisions which are spaced apart parallel with the slot to enable the blade to be located securely in a selectable position. The incisions may be formed on at least one longitudinal side of the slot, or may be formed on at least one lateral edge of the blade extending perpendicularly to the longitudinal edges of the blade. Each slot may extend at right angles, or may extend parallel to the blade cutting edges. Alternatively, the slot may be in the form of a cross-shaped slot having a portion extending at right angles, and a portion extending parallel to the blade cutting edges. The slot may be equal in width to the corresponding dimension of an associated projection of a hair-cutting device so that the blade may be retained on the projections of the cutting device while being displaceable in the longitudinal direction of the slot.

A plurality of incisions extending from the slot-shaped aperture along at least one longitudinal side thereof, enable the blade to be located in the cutting device in a plurality of selectable positions by bringing the projection into engagement with a selective one of said incisions. In the embodiment where the slot-shaped apertures extend at right angles to the blade cutting edges, the position of the cutting edge of the blade can be adjusted in the working direction of a hair-cutting device. It is thus possible to control the length to which hair is cut, or thinned, even for a hair-cutting device in which there is no control over the length of the row of teeth which protrude beyond the cutting edge of the blade.

In one embodiment of the invention, the slot-shaped apertures extend parallel to the blade cutting edges so that the blade can be adjusted transversely in the cutting device. This enables the cutting portions of the blade to be aligned with the gaps between the teeth provided on the hair-cutting device, so that longer or shorter cutting portions are located in the gaps between the teeth while some of the cutting portions are overlapped or masked by the teeth. As a result, the amount of thinning of the blade can be controlled by laterally displacing the blade.

The blade cutting edge can be easily displaced either in the transverse or the longitudinal direction if the blade is provided with a cross-shaped aperture as described earlier. However, it is impossible to obtain a simultaneous right angle and parallel adjustment of the cutting edge with this embodiment.

In a further embodiment, a plurality of spaced-apart apertures are provided in a blade, which extend in rows and columns. The rows and columns extend at right angles to, and are parallel to the cutting edge of the blade respectively. The blade cooperates with two pins provided on the hair-cutting device so that it can be located in a large number of alternative positions. In utilizing this embodiment, the blade may be adjusted to practically any desired position.

Other objects and features of the present invention will become apparent from the following detailed description when taken in connection with the accompanying drawing which discloses several embodiments of the invention. It is to be understood that the drawings are designed for the purposes of illustration only, and are not intended as a definition of the limits and scope of the invention disclosed.

In the drawing, wherein similar reference numerals denote similar elements throughout the several views:

FIG. 1 is a plan view of a blade in accordance with the invention for use in a hair-cutting device as shown in broken lines;

FIG. 2 illustrates an alternative embodiment of a blade of the present invention in which the portions of the longitudinal edges constituting the cutting edge are large in comparison with the noncutting portions;

FIG. 3 illustrates a further embodiment of a blade in which the noncutting portions are large in comparison with the cutting portions of the blade; and

FIGS. 4-7 are plan views of parts of various blades in accordance with the invention each showing various apertures formed in the blade enabling the blade to be located adjustably in a hair-cutting device.

Referring to FIGS. 1-3, blades 10 are similar to conventional blades such as razor blades. They are constructed in the form of flat, elongated blades, like razor blades, having cutting edges 12 and 14 formed on their opposite longitudinal edges, and having apertures 16 formed in their longitudinal central zone for locating the blade in an associated hair-cutting device 18. At least one of the longitudinal edges of each blade is provided with cutting portions and noncutting portions which are located alternately along its length. The cutting and noncutting portions 20 and 22 have widths a and b respectively.

FIG. 1 shows a blade 10 positioned in a hair-cutting device 18. Hair-cutting device 18 has a row of parallel teeth 24 which can be displaced with respect to the cutting edge 14 of the blade. Longitudinal edge 14 of blade 10 is provided with cutting portions 20 and noncutting portions 22 of width a and b respectively, which are dimensioned so that cutting portions 20 and noncutting portions 22 lie alternately between adjacent teeth 24 of the row of teeth. When cutting device 18 is passed through the hair of a user with a motion similar to a combing motion, the hair passing between two teeth associated with a cutting portion 20 is shortened while the hair passing between two teeth associated with noncutting portion 22 remains unshortened. Thus, every time the cutting device is passed through the scalp of a user, only a certain portion of the hair comes in contact with a cutting portion of the blade and thus only this portion of the hair is cut. In the embodiment illustrated, only about one-half of the hair comes in contact with a cutting portion of the blade so that the effect of the device is a thinning out of the hair of the user. The distance by which teeth 24 overlap cutting portions 20 determines the relative difference in length between the hair which is shortened and the hair which remains unshortened. In certain embodiments of the invention, the length of the teeth is adjustable to enable the length to which the hair is cut to be adjusted.

Cutting edge 12, located inside cutting device 18 as illustrated in FIG. 1, is shown as a conventional cutting edge which extends over substantially the entire length of one longitudinal side of the blade. By reversing the blade so that the second cutting edge 12 is adjacent to teeth 24, the hair-cutting device can be utilized for shortening rather than thinning the hair. Both longitudinal edges 12 and 14 of the blade could also be formed as thinning-out cutting edges having cutting portions and noncutting portions.

The noncutting portions 22 may be formed in a simple manner by punching out or stamping out crenellations or castellations in one longitudinal side of blade 10 before hardening and grinding, thus producing recessed portions which are not sharpened when the blade is subsequently ground. Of course, both longitudinal side edges of a blade 10 may be punched or stamped out. Alternatively only portions of the longitudinal side edge or edges of a blade may be ground, thus leaving noncutting portions between sharpened cutting portions.

The blades illustrated in FIGS. 2 and 3 differ from those described before in that the widths a and b of the cutting and noncutting portions are changed. In blade 10 illustrated in FIG. 2, the width a of the cutting portions is twice as large as the width of b of the noncutting portions (a = 2b). Thus, when this blade is inserted in a cutter 18, each cutting portion 20 extends over two adjacent gaps between three adjacent teeth 24. The noncutting portions 22 extend over a single gap between two adjacent teeth between groups of teeth provided with the cutting portions. The converse situation is obtained if a blade 10 as illustrated in FIG. 3 is utilized in which the width a of cutting portions 20 is half the width b of the noncutting portions 22 (2a = b).

In the embodiments illustrated in FIGS. 1-3, apertures 16 formed in blade 10 for its attachment to a hair-cutting device, such as cutting device 18, have a shape, as illustrated, which enables the blade to be securely located in the cutting device. If the cutting device has attaching pins of a complementary cross section to the apertures formed in blade 10, then unsuitable blades having apertures of different dimensions or shape cannot be used. Apertures 16 are each shaped in the form of a circle which is substantially flattened on the sides thereof, parallel with the longitudinal, side edges of the blade. There is an incision 26 of reduced width adjoining each aperture and extending towards the adjacent transverse side edge of the blade.

FIGS. 4-7 illustrate various forms of apertures for locating the blades 10 in an associated cutting device, the apertures being constructed to enable the blade to be located adjustably in the cutting device.

In the embodiment of the blade illustrated in FIG. 4, the aperture in the blade takes the form of an elongated slot 28 extending at right angles to the blade cutting edges 12, 14. Slot 28 has a width which is substantially equal to or slightly larger than the corresponding dimensions of the associated projection or mounting pin 30 provided on hair-cutting device 18. Thus, blade 10 may be retained on the projection 30 of the hair-cutting device with projection 30 occupying various positions in slot 28. The blade can thus occupy various positions relative to hair-cutting device 18. However, there is no provision in this embodiment for the blade to be moved in a direction which is parallel to its axis. On the right of the blade 10 a projection 30 of the hair-cutting device is shown which would extend through the second slot 28 symmetrically disposed relative to the first slot in the portion of the blade which is not shown.

On the longitudinal side of slot 28, adjacent the end of blade 10, a plurality of incisions 32 are provided which extend from slot 28 and are uniformly spaced apart and adapted to receive an extension 34 provided on projection 30 of hair-cutting device 18. As an alternative to the provision of incisions 32, incisions 32' shown on the outer edge of the blade 10 might be provided to cooperate with a protrusion provided separately from the projections 30 in the hair-cutting device 18. The extensions 34 on the projection 30 would then not be necessary.

The embodiment of the blade illustrated in FIG. 5 corresponds to that described with reference to FIG. 4 except that slot 28 does not extend at right angles to the cutting edges 12, 14 but parallel thereto. Thus, extension 34 of the associated projections 30 of the cutting device 18 will extend in the direction at right angles to the cutting edges 12, 14 of the blade. It can be seen that the blade of FIG. 5 may be located in various positions relative to projections 30, thus enabling the cutting portions of the edge of the blade to be located so that parts of the cutting portions are masked by teeth 24 of hair cutting device 18. The hair-thinning or cutting effect of the blades can therefore be varied.

FIG. 6 illustrates a blade 10 provided with a cross-shaped slot 36 forming an aperture which can be considered to be a combination of the embodiment illustrated in FIGS. 4 and 5. Thus, the blade of FIG. 6 can be located in a selected position which is both perpendicular as well as parallel to cutting edges 12 and 14. In FIG. 6, projections 30 provided on the hair-cutting device require two extensions 34 which are at 90.degree. to each other, and which can engage incisions 32 provided in the edges of either of the perpendicularly extending portions of cross-shaped slot 36. It utilizing this embodiment of the invention, the blade can be adjusted between a plurality of positions in which the longitudinal axis of the blade is moved relative to cutting device 18 and in which the transverse axis remains constant, or the transverse axis of the blade is moved relative to the cutting device 18 and the longitudinal axis remains constant.

FIG. 7 illustrates an embodiment of the blade in which the blade can be adjusted between many positions in directions both at right angles and parallel to the cutting edges. Blade 10 is provided with an array of round apertures 38, and the hair-cutting device 18 intended to be utilized with this blade has two pins 30 which are of circular cross section and adapted to engage holes 38. Apertures 38 extend in columns and rows both parallel and transverse with cutting edges 12 and 14, to form a regular rectangular array so that blade 10 may be located in as many different positions as possible. Apertures 38 are projections 30 provided in the cutting device are relatively small in diameter. Preferably both apertures 38 and projections 30 are of circular cross-sectional shape, but of course other cross-sectional shapes can also be utilized, such as, for example, triangles, squares, and the like.

While only a few embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention.

Claims

What is claimed is:

1. A blade in combination with a hair-cutting device of the kind having a row of teeth adapted to lie adjacent one longitudinal edge of the blade, said blade having at least one longitudinal edge comprising cutting portions and noncutting portions alternately spaced along the length of said one longitudinal edge, the width of the noncutting portions of the blade being substantially equal to the distance between two teeth of said row of teeth, the blade being disposed in said hair-cutting device so that the noncutting portions and cutting portions of said longitudinal edge are in alignment with the gaps between the teeth.

2. The blade according to claim 1 wherein two opposed longitudinal edges of the blade are provided with cutting portions, and noncutting portions, the width of said cutting portions and noncutting portions on one longitudinal edge differing from the width of the cutting and noncutting portions on the other longitudinal edge.

3. The blade according to claim 2 comprising a plurality of spaced-apart apertures arranged in rows and columns, the rows and columns being respectively parallel with and at right angles to the longitudinal edges of the blade, said apertures being adapted to co-operate with at least two projections provided on the hair-cutting device.

4. The blade in combination with a haircutting device according to claim 1 wherein said noncutting portions are recessed relative to the cutting portions thereof, so that the cutting portions protrude beyond the noncutting portions, at least one aperture is formed in said blade and adapted to cooperate with correspondingly shaped projections provided on the hair cutting device to locate the blade in the hair-cutting device, an incision extending from each aperture, said aperture defined by the blade has the shape of an elongated slot, the blade defining a plurality of said incisions which are spaced apart parallel with the slot to enable the blade to be located securely in a selectable position, said slot extends at right angles to the blade cutting edges.

5. The blade according to claim 4 wherein the incisions are defined on at least one longitudinal side of the slot.

6. The blade according to claim 4 wherein the incisions are defined on at least one lateral edge of the blade extending perpendicularly to the longitudinal edges of the blade.

7. The blade in combination with a hair-cutting device according to claim 1 wherein said noncutting portions are recessed relative to the cutting portions thereof, so that the cutting portions protrude beyond the noncutting portions, at least one aperture is formed in said blade and adapted to cooperate with correspondingly shaped projections provided on the hair-cutting device to locate the blade in the hair-cutting device, an incision extending from each aperture, said aperture defined by the blade has the shape of an elongated slot, the blade defining a plurality of said incisions which are spaced apart parallel with the slot to enable the blade to be located securely in a selectable position, said slot extends parallel to the blade cutting edges.

8. The blade according to claim 7 wherein said slot is cross-shaped having a portion extending at right angles to the blade cutting edges and a portion extending parallel to the blade cutting edges.

9. The blade in combination with a hair-cutting device according to claim 7, wherein said incisions are defined on at least one longitudinal side of the slot.

10. The blade in combination with a hair-cutting device according to claim 1 wherein the width of the noncutting portions and the width of the cutting portions of the longitudinal side of the blade are each equal to the distance between adjacent teeth of the row of teeth provided on the hair-cutting device so that the noncutting portions and cutting portions of the blade may be located between alternate successive teeth of the hair-cutting device.

11. The blade in combination with a hair-cutting device according to claim 1 wherein the cutting portions and the noncutting portions respectively constitute edge portions, at least one of said edge portions has a width which is equal to a multiple of the distance between two adjacent teeth of the row of teeth of the hair-cutting device.

12. The blade in combination with a hair-cutting device according to claim 1, wherein said noncutting portions are recessed relative to the cutting portions thereof, so that the cutting portions protrude beyond the noncutting portions, at least one aperture is formed in said blade and adapted to cooperate with correspondingly shaped projections provided on the hair-cutting device to locate the blade in the hair-cutting device, and an incision extending from each aperture, said aperture defined by the blade has the shape of an elongated slot, the blade defining a plurality of said incisions which are spaced apart parallel with the slot to enable the blade to be located securely in a selectable position, the width of said slot being formed at least substantially equal to the corresponding dimension of projections on said hair-cutting device such that the blade is retainable on said projections yet selectably displaceable in the axial direction of said slot.

13. The blade in combination with a hair-cutting device according to claim 1, wherein said blade being adjustably disposed parallel to said longitudinal edge in said hair-cutting device.