Bladeset for electric hair cutting device

Abstract

A bladeset (24) of the present invention includes a movable blade (26) having a plurality of teeth (46). The bladeset (24) also includes a stationary blade (28) having a plurality of movable teeth (48). The moving blade (26) is movable relative to the stationary blade (28) along a cutting axis (40). Each tooth of the plurality of teeth (48) of the stationary blade (28) has a tooth depth measured from a tip (62) of the tooth to a root (58) of the tooth. The tooth depth is at least about 0.150 inches. The plurality of teeth (48) of the stationary blade (28) has a tooth pitch of preferably about 0.032 inches to about 0.058 inches, more preferably a tooth pitch of about 0.035 inches to about 0.054 inches, and even more preferably a tooth pitch of about 0.038 inches to about 0.050 inches.

Description

BLADESET FOR ELECTRIC HAIR CUTTING DEVICERELATED APPLICATIONThe present application is a PCT of, and claims 35 U.S.C. 119 priority from, US Provisional Application No. 63 / 572,520 filed April 1, 2024, the entire contents of which are incorporated by reference herein.BACKGROUND

[0001] The present invention relates generally to electric hair cutting devices such as hair clippers and hair trimmers, and more specifically to blades.

[0002] Electric hair cutting devices include a moving blade that laterally reciprocates in relation to a stationary blade to perform a cutting action. Both the moving blade and the stationary blade have teeth, and both blades are collectively referred to as the bladeset. Hair caught between the teeth of the blades is sheared through movement of the moving blade relative to the stationary blade.

[0003] Contemporary electric hair cutting devices also include an electric motor that is powered by an on-board battery, and / or via a supply voltage from an outlet. The motor is mechanically coupled to the moving blade to produce the reciprocation of the moving blade via one of a variety of different mechanical linkage formats (e.g. eccentric cam arrangements, pivot arm arrangements, etc.).

[0004] Additional features may also be included, such as cutting length adjustment mechanisms used to finely control the length of hair which remains after being cut by the device. One such cutting length adjustment mechanism in general involves moving thestationary blade relative to the moving blade using what is known in the art as a taper lever mechanism. The stationary blade teeth have an increasing thickness moving from the tips thereof toward the root thereof. Hair must extend at least as far as this thickness before reaching the interface of the teeth of the moving blade and the teeth of the stationary blade where it is cut. These taper lever mechanisms allow the user to set where, along the thickness of the stationary blade, the interface between the teeth of the moving blade and the teeth of the stationary blade resides, and hence determine where along the variable thickness of the stationary blade hair must pass through before being cut. Such a configuration allows for fine adjustment of the length of hair that remains after being cut.

[0005] Positioning the tips of the moving blade teeth closer to the tips of the stationary blade teeth means that hair must pass through a relatively small stationary blade thickness before being cut, hence resulting in a shorter length of hair that remains on the scalp. Conversely, positioning the tips of the moving blade teeth farther away from the tips of the stationary blade teeth means that the hair must pass through a larger stationary blade thickness before being cut, hence resulting in a longer length of hair that remains on the scalp.

[0006] Some bladesets are more suited for very close to skin cutting, lining, and edgework, while others are more suitable for bulk removal of hair away from the skin. Bladesets configured for close to skin cutting are typically seen in hair trimmers. Bladesets configured for bulk removal of hair away from the skin are typically seen in hair clippers.There are notable differences between these bladesets.

[0007] For example, the stationary blades of hair trimmer bladesets typically have shallow tooth depths (i.e. the value of the length of a tooth measured from its tip to its root), are relatively small, and have a fine pitch (i.e. a relatively small distance between centerlines of adjacent teeth). This combination of shallow teeth and close pitch allows for a close safe cut with minimal residual hair left after a first pass. Typical pitch values are no greater than about 0.045 inches, and typical depth values are less than about 0.100 inches. Conventional wisdom suggests avoiding greater tooth depths because the finer pitch requires relatively thin teeth. Thin teeth with large tooth depths are conventionally understood to be weak and may break off.

[0008] One drawback of shallow teeth is a reduction in the ability to finely adjust cutting length using a taper lever mechanism. The depth of the teeth dictates the maximum range of adjustment of a linear distance perpendicular to the cutting direction between the tips of the moving blade teeth and the tips of the stationary blade teeth. This range of adjustment is the range of values wherein hair may freely pass between the stationary blade teeth and the moving blade teeth so that it will be cut. Shorter tooth depths thus result in reduced range of selectable cutting lengths using the taper lever.

[0009] As another example, hair clipper stationary blades typically have thicker teeth, coarser pitches, and greater tooth depths compared to their hair trimmer bladeset counterparts. Because the teeth of the stationary blade of hair clippers are relatively thick and the pitch is coarse, these blades cannot achieve the closeness of cut compared to trimmer bladesets. However, their greater tooth depth and coarser pitch allows for a greater range of cutting length adjustment making them more versatile and well suited for bulkhair removal and blending. Typical tooth depths of hair clipper stationary blades are about 0.160 inches to about 0.280 inches. These greater depths are possible due to the coarser pitch and thicker teeth of these stationary blades, with the coarser pitch typically in the range of about 0.062 inches to about 0.095 inches.

[0010] Because of the differences in application above, professionals in many instances will have different hair cutting devices with different bladesets to address these different applications. As a result, more tools may be required for a given haircut, particularly haircut styles that require very close cutting but also good blending, such as a traditional fade.

[0011] Accordingly, there is a need for an improved bladeset that provides the advantages of both a trimmer bladeset, and a clipper bladeset in a single unit.SUMMARY

[0012] The above-listed need is met or exceeded by a bladeset for an electric hair cutting device having a desirable pitch range at a specific tooth depth. Such a configuration strikes a balance of close to skin cutting and length adjustment. An embodiment of such a bladeset includes a movable blade having a plurality of teeth. The bladeset also includes a stationary blade having a plurality of teeth. The moving blade is movable relative to the stationary blade along a cutting axis. Each tooth of the plurality of teeth of the stationaiy blade has a tooth depth measured from a tip of the tooth to a root of the tooth. The tooth depth is at least about 0.150 inches. The plurality of teeth of the stationary blade has a tooth pitch of preferably about 0.032 inches to about 0.058 inches, more preferably a toothpitch of about 0.035 inches to about 0.054 inches, and even more preferably a tooth pitch of about 0.038 inches to about 0.050 inches.

[0013] In certain embodiments, each tooth of the plurality of teeth of the stationary blade has a tooth point thickness measured at the point of each tooth and in a direction perpendicular to the cutting direction, wherein the tooth point thickness is about 0.008 inches to about 0.025 inches.

[0014] In certain embodiments, each tooth of the plurality of teeth of the stationaiy blade has a tooth point width measured at the point of each tooth and in a direction parallel to the cutting direction, wherein the tooth point width is about 0.006 inches to about 0.020 inches.

[0015] In certain embodiments, each tooth of the plurality of teeth of the stationary blade includes an extension portion extending past the root of each tooth and away from the tip of each tooth. A length of the extension portion of each tooth of the plurality of teeth of the stationary blade is greater than the tooth depth.

[0016] Other aspects, objectives and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings:

[0018] FIG. 1 is a perspective view of an exemplary embodiment of an electric hair cutting device incorporating a bladeset constructed in accordance with the teachings herein;

[0019] FIG. 2 is a top view of a stationary blade of the bladeset of FIG. 1;

[0020] FIG. 3 is a partial top view of the stationary blade of FIG. 2;

[0021] FIG. 4 is a side view of the stationary blade of FIG. 2; and

[0022] FIG. 5 is a fragmentary bottom view of the stationary blade of FIG. 2.

[0023] While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims.DETAILED DESCRIPTION

[0024] Turning now to the drawings, FIG. 1 illustrates an exemplary embodiment of an electric hair cutting device embodied herein for non-limiting example as a hair clipper 20. Hair clipper 20 includes a housing 22 having a first end and a second end. A bladeset 24 is mounted at the first end. Bladeset 24 includes a moving blade 26 which moves relative to a stationary blade 28 to produce a hair cutting action. While the following description will be provided in the context of a hair clipper of the type shown in FIG. 1, the invention is not limited to the device illustrated, and it is envisioned that the teachings herein may be readily applied to other devices such as hair trimmers, or any electric hair cutting device having a reciprocating blade.

[0025] Hair clipper 20 includes an internal electric motor 30 powered via a power source 32 (both shown hidden). It will be recognized from the description herein that the invention is not constrained to a particular power source or a particular motor type. For example, power source 32 may be embodied by an internal battery carried by housing 22 or may be an external power source such as a supply voltage provided by a wall outlet.

[0026] A mechanical linkage (not shown) connects motor 30 to bladeset 24 to induce a reciprocating motion to moving blade 26 relative to stationaiy blade 28 to provide a cutting action. More specifically, moving blade 26 is operable to reciprocate in first and second directions 36, 38 along a cutting axis 40. Cutting axis 40 is defined generally at the line defined by the tips of a plurality of moving teeth 46 of moving blade 26 as located relative to the tips of a plurality of stationary teeth 48 of stationary blade 28.

[0027] Hair clipper 20 also includes an adjustment mechanism 34 for adjusting a relative distance between the tips of the teeth of moving blade 26 and the tips of the teeth of stationary blade 28. In the illustrated embodiment, adjustment mechanism 34 moves stationary blade 28 relative to moving blade 26 along a longitudinal axis of hair clipper 20.

[0028] With reference to FIG. 2, stationary blade 28 will be described in greater detail. Stationary blade 28 includes a front portion with a plurality of teeth 48 formed thereon. One or more mounting holes 52 may also be provided near a rear portion of stationary blade 28 and are used to mount stationary blade to hair clipper 20 as is shown in FIG. 1. When viewed orthogonally to surface 56 as shown in FIG. 2, teeth 48 extend from a leading edge or root 58 of stationary blade 28. As may be seen in FIG. 2, root 58 isexposed at gaps between adjacent teeth 48 and is generally linear and parallel to cutting axis 40 (see FIG. 1).

[0029] With reference to FIG. 3, it has been found after extensive research and testing that with a particular combination of tooth depth “d” and tooth pitch “p,” a balance may be achieved wherein teeth 48 have enough structural rigidity to allow for a fine pitch akin to a hair trimmer blade as discussed above, but also allow for greater adjustment via adjustment mechanism 34 given the appreciable tooth depth “d.”’ Tooth depth “d,” as used herein, refers to a distance from root 58 of a tooth 48 to a point or tip 62 of that tooth. It is contemplated herein that teeth 48 may have alternating tooth depths such as the staggertooth configuration as is shown in U.S. Patent No. 7,841,091 to Melton, the teachings and disclosure of which are incorporated by reference herein. In the case of alternating tooth depths, tooth depth “d” as used herein refers to the largest tooth depth presented by the alternating tooth depths.

[0030] It has been found that a tooth depth “d” of at least about 0.150 inches, and a tooth pitch “p” of about 0.032 inches to about 0.058 inches, more preferably a tooth pitch of about 0.035 inches to about 0.054 inches, and even more preferably a tooth pitch of about 0.038 inches to about 0.050 inches provides a sufficient amount of depth for allowing a range of adjustment using adjustment mechanism 34 but also a fine pitch for optimal cutting on a first pass.

[0031] It has been found that at the above combination of depth and pitch, stationary teeth 48 provide the advantages of a hair trimmer and its efficacy in close to skin cutting, but also allow for an appreciable range of adjustment for accommodating different haircutting lengths. Accordingly, it is no longer necessary in many applications to require both a hair trimmer and hair clipper, as a bladeset with the above parameters addresses the applications of both types of devices.

[0032] Another unexpected result found with the particular tooth depth and blade pitch described herein is exceptional bulk hair removal over conventional hair clipper blades of a coarser pitch. Conventional wisdom indicates that hair clipper stationary blades need to have a coarse pitch to handle the volume of hair. Unexpectedly in the instant invention, it was found that more cutting edges of a finer pitch blade within the values described herein results in each cutting action involving a relatively lesser amount of hair compared to a blade of coarser pitch. This results in a reduction in the cutting load spike or demand on the motor and thus results in a smoother cutting operation.

[0033] With these parameters, a tooth point width “w” of each tooth point 62 (see FIG. 3) measured parallel to the cutting direction 40 (see FIG. 1) of about 0.006 inches to about 0.020 inches may also be employed. With these parameters, it is also possible to employ a relatively thin tooth point thickness “t” of each tooth point 62, as is shown in FIG. 4 of about 0.008 inches to about 0.025 inches. As used herein, “about” is used to accommodate for typical manufacturing tolerances understood by one skilled in the art of hair clipper blade manufacture.

[0034] With reference to FIG. 5, the same illustrates a bottom surface 66 opposite top surface 56 (see FIG. 2). As may be seen in this view, each tooth 48 includes an extension portion 64 which extends a length “1” past root 58 and away from tooth points62. It has been found that extension portion length “1” is ideally greater than tooth depth“d.” These extension portions 64 aid in feeding hair through teeth 48.

[0035] All references, including publications, patent applications, and patents cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

[0036] The term “electric hair cutting device” as used herein includes any electric hair cutting device that includes a motor which drives a moving blade to cut hair, including but not limited to hair clippers, hair trimmers, and electric shavers. The terms “hair clipper” and “hair trimmer” are used interchangeably unless otherwise noted, and do not limit the scope or applicability of the invention herein to either particular variant.

[0037] The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplarylanguage (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any nonclaimed element as essential to the practice of the invention.

[0038] Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

Claims

CLAIMS:

1. A bladeset (24) for an electric hair cutting device (20), comprising: a movable blade (26) having a plurality of teeth (46); a stationary blade (28) having a plurality of teeth (48), wherein the moving blade is movable relative to the stationary blade along a cutting axis (40); wherein each tooth of the plurality of teeth of the stationary blade has a tooth depth measured from a tip (62) of the tooth to a root (58) of the tooth, and wherein said tooth depth is at least about 0.150 inches; and wherein the plurality of teeth of the stationary blade has a tooth pitch of about 0.032 inches to about 0.058 inches.

2. The bladeset of claim 1, wherein the plurality of teeth (48) of the stationary blade (28) has a tooth pitch of about 0.035 inches to about 0.054 inches.

3. The bladeset of claim 1, wherein the plurality of teeth (48) of the stationary blade (28) has a tooth pitch of about 0.038 inches to about 0.050 inches.

4. The bladeset of claim 1, wherein each tooth (48) of the plurality of teeth of the stationary blade (28) has a tooth point thickness measured at the point (62) of each tooth and in a direction perpendicular to the cutting direction, wherein the tooth point thickness is about 0.008 inches to about 0.025 inches.

5. The bladeset of claim 1, wherein each tooth of the plurality of teeth (48) of the stationary blade (28) has a tooth point width measured at the point (62) of each tooth and in a direction parallel to the cutting direction, wherein the tooth point width is about 0.006 inches to about 0.020 inches.

6. The bladeset of claim 1, wherein each tooth of the plurality of teeth (48) of the stationary blade (28) includes an extension portion (64) extending past the root (58) of each tooth and away from the tip (62) of each tooth.

7. The bladeset of claim 6, wherein a length of the extension portion (64) of each tooth of the plurality of teeth (48) of the stationary blade (28) is greater than the tooth depth.

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