Patent Description:
Conventional handheld hair trimmers typically include a head including a stationary blade and a movable blade. A motor is operable to reciprocate the movable blade relative to the stationary blade to cut hairs. In at least some known handheld trimmers, the stationary blade and the movable blade include blade teeth that are relatively planar and extend to end points to define the blade edges of the stationary and movable blades. To obtain a suitable sharpness of these teeth, the thickness of the blades must be relatively thin. Following repeated use of the trimmer, the tips of the blade teeth may deteriorate and possibly break.

Additionally, during operation of typical trimmers, the blades are moved along a user's skin and the blades cut hairs extending between the teeth. However, the blades may irritate and even cut the user's skin. Accordingly, some handheld trimmers include guards that extend next to the blades to slightly space the edges of the blades from the user's skin during trimming. However, these guards can prevent or otherwise inhibit the blades from properly cutting hairs. In addition, a user's skin may be pinched in the spacing between the guard and the blade edges.

<CIT> discloses a shaving device having a face engaging member so constructed as to provide hair guiding portions of extreme thinness. <CIT> discloses a beard trimmer.

There is a need, therefore, for a hair grooming appliance that provides for a suitably sharp blade edge while providing desired durability, and further includes a guard that reduces the risk of pinching and allows for a trimming hair of a wider range of hair lengths.

According to the claimed invention, there is provided a head for an electrical handheld trimmer as claimed in claim <NUM> and an electric handheld hair trimmer as claimed in claim <NUM>. Various optional features according to embodiments of the claimed invention are set forth in the dependent claims and are described below.

Referring now to the drawings and in particular to <FIG> and <FIG>, a handheld hair grooming appliance according to one embodiment is illustrated in the form of an electric handheld hair trimmer, indicated generally by <NUM>. It is contemplated, however, that the embodiments described herein may be used on other handheld hair grooming appliances such as, for example, electric shavers and hair clippers. The trimmer <NUM> includes a handle, indicated generally at <NUM>, and a head (broadly a hair-grooming assembly), indicated generally at <NUM>, mounted on and supported by the handle. Together, the handle <NUM> and the head <NUM> generally define a longitudinal axis A-A of the trimmer <NUM>. A suitable motor (not shown) is disposed in the handle <NUM> along with a drive assembly <NUM> (shown in <FIG>). The drive motor may be powered by one or more batteries (not shown) disposed within the handle <NUM> and/or by another suitable internal or external electrical power source. In the illustrated embodiment, the head <NUM> is detachable from the handle <NUM>. Accordingly, the head <NUM> may be removed and another head <NUM> may be positioned on the handle <NUM>. However, in other embodiments the head <NUM> may be affixed to handle <NUM> without departing from the scope of the invention.

Referring to <FIG>, the head <NUM> includes a blade assembly <NUM> operatively connected to the motor by the drive assembly <NUM>, a blade guard <NUM>, and mounting pins <NUM>. Mounting arms project outward from the handle with the head <NUM> extending laterally between the arms. The mounting pins <NUM> extend through the respective mounting arm and the blade guard <NUM> to pivotally mount the head <NUM> on the handle <NUM>. Accordingly, the head <NUM> is pivotable about a pivot axis extending through the mounting pins <NUM>. In other embodiments, the position of the head <NUM> may be fixed (i.e., non-pivotable) relative to the handle <NUM>. In some embodiments, the head <NUM> may be switched between a pivotable configuration and a non-pivotable configuration. In further embodiments, the head <NUM> may be pivotable about more than one pivot axis.

The blade assembly <NUM> generally comprises a stationary blade <NUM> and a movable blade <NUM>. The drive assembly <NUM> is operable to laterally reciprocate the movable blade <NUM> relative to the stationary blade <NUM> to trim hair. It is understood that the trimmer head <NUM> may be of other configurations without departing from some aspects of the present invention.

With reference to <FIG> and <FIG>, the stationary blade <NUM> is suitably a dual-edge blade assembly including a first transverse edge portion <NUM>, a second transverse edge portion <NUM>, and a middle portion <NUM>. The first transverse edge portion <NUM> includes a set of blade teeth <NUM> defining a first edge <NUM> of the blade <NUM>. The second transverse edge portion <NUM> includes an opposite set of blade teeth <NUM> defining a second edge <NUM> of the blade <NUM>. In other embodiments, the blade assembly <NUM> may be a single-edge blade assembly or any other suitable blade assembly that enables the trimmer <NUM> to operate as described herein.

The illustrated first edge <NUM> and second edge <NUM> are straight. In other embodiments, the first edge <NUM> and/or the second edge <NUM> may be at least partially curved or angled.

In the illustrated embodiment, the middle portion <NUM> is disposed intermediate and spans between the first transverse edge portion <NUM> and the second transverse edge portion <NUM> and includes a planar upper surface <NUM>. In other embodiments, the middle portion <NUM> may include, without limitation, an apex, a curved surface, an angled surface, and any other suitable portion. For example, in some embodiments, the middle portion <NUM> may include an apex connecting the first transverse edge portion <NUM> and the second transverse edge portion <NUM>.

The first transverse edge portion <NUM> includes a first upper surface <NUM> extending from the first edge <NUM> to the upper surface <NUM> of the middle portion <NUM>. The second transverse edge portion <NUM> includes a second upper surface <NUM> extending from the second edge <NUM> to the upper surface <NUM> of the middle portion <NUM>. The first upper surface <NUM> and the second upper surface <NUM> may include at least one of an angled surface, a concave curve, and a convex curve extending along at least a portion of the respective upper surface <NUM>, <NUM> between the middle portion <NUM> and the respective edge <NUM>, <NUM>. In the illustrated embodiment, the first upper surface <NUM> and the second upper surface <NUM> are angled. The dual angles thus form the appearance of dual beveled edges on opposite sides of the middle portion <NUM>. As used herein, the terms "bevel" and "beveled" refer to a surface that is oblique to an adjacent surface.

This beveling of the stationary blade <NUM> is believed to provide a sharper and more durable blade than conventional blades that are general flat or planar because the stationary blade <NUM> is beveled from the upper surface <NUM> to the respective edges <NUM>, <NUM>. For example, the bevels of the illustrated stationary blade <NUM> allow the first transverse edge portion <NUM> and the second transverse edge portion <NUM> to come to a relatively sharp point in which the blade is thinner, i.e. sharper, at the first and second edges <NUM>, <NUM> than for conventional blades. In addition, the bevels allow the thickness of the stationary blade <NUM> to change at a constant rate as the blade extends from the middle portion <NUM> to the respective edges <NUM>, <NUM>. Also, the angle of the beveling allows the blade <NUM> to have an increased thickness in the middle portion <NUM>, which reduces warpage of the blade <NUM>. In contrast, at least some known blades include multiple surfaces with different slopes. In such known blades, there may be high stress areas in portions of the blade where the slope changes. Such conventional blades may also include sections which are thin and plate-shaped. As a result, such blades may deteriorate and even break after repeated use. In contrast, the stationary blade <NUM> of the illustrated embodiments has a sharper point and increased durability as a result of the bevels.

The illustrated stationary blade <NUM> has a transversely extending length <NUM> (<FIG>). In some embodiments, this length <NUM> is in the range of about <NUM> to about <NUM> depending on the intended use of the trimmer <NUM>, and more preferably in the range of about <NUM> to about <NUM>. In the illustrated embodiment, the length <NUM> is approximately <NUM>. In other embodiments, the stationary blade <NUM> may be of another suitable length and remain within the scope of the invention.

Referring now to <FIG>, the stationary blade <NUM> and the movable blade <NUM> are in shearing contact with each other to define a cutting plane <NUM> therebetween. Specifically, the movable blade <NUM> is configured to contact lower surfaces <NUM> of the respective first and second transverse edge portions <NUM>, <NUM> (shown in <FIG>) along the cutting plane <NUM> as the movable blade reciprocates. The upper surface <NUM> of the middle portion <NUM> is substantially parallel to the cutting plane <NUM>. The first upper surface <NUM> and the second upper surface <NUM> (shown in <FIG>) are angled relative to the cutting plane <NUM>.

In the illustrated embodiment, the stationary blade <NUM> is symmetric about a midline of the middle portion <NUM>. Accordingly, the second transverse edge portion <NUM> has dimensions that are substantially equal to the first transverse edge portion <NUM>. Therefore, the description herein, including dimensions, of the first transverse edge portion <NUM> may also apply to the second transverse edge portion <NUM>, and vice versa. In other embodiments, the second transverse edge portion <NUM> and the first transverse edge portion <NUM> may differ and remain within the scope of the invention.

As shown in <FIG>, the first upper surface <NUM> extends continuously at a constant slope from the upper surface <NUM> of the middle portion <NUM> to the first edge <NUM>. The first upper surface <NUM> thus defines an angle <NUM> with the cutting plane <NUM>. In some embodiments, this angle <NUM> is suitably in the range of about <NUM>° to about <NUM>°, and more preferably in the range of about <NUM>° to about <NUM>°. In the illustrated embodiment, the angle <NUM> is approximately <NUM>°.

The first transverse edge portion <NUM> also has a width <NUM> (<FIG>) extending from the first edge <NUM> to the middle portion <NUM>. In suitable embodiments, this width <NUM> is in the range of about <NUM> to about <NUM>, more preferably in the range of about <NUM> to about <NUM>, and even more preferably in the range of about <NUM> to about <NUM>. In the illustrated embodiment, the width <NUM> of the first transverse edge portion <NUM> is approximately <NUM>.

The first transverse edge portion <NUM> further has a generally planar lower surface <NUM> opposite the first upper surface <NUM>. The lower surface <NUM> is generally parallel to the upper surface <NUM> of the middle portion <NUM> and the cutting plane <NUM>. The first upper surface <NUM> extends relative to the lower surface <NUM> at a constant angle from the first edge <NUM> to the middle portion <NUM>. Accordingly, with reference to <FIG>, the first transverse edge portion <NUM> has a varying thickness <NUM> between the first upper surface <NUM> and the lower surface <NUM>. The first transverse edge portion <NUM> has a minimum thickness <NUM> at the first edge <NUM>. In some embodiments, the thickness <NUM> at the first edge <NUM> is in the range of about <NUM> millimeters (mm) to about <NUM>. In the illustrated embodiment, the thickness <NUM> at the first edge <NUM> is approximately <NUM>. With reference back to <FIG>, each of the first and second transverse edge portions <NUM>, <NUM> includes a respective set of teeth <NUM> at least partially forming the corresponding first and second edges <NUM>, <NUM>. Each tooth <NUM> has a width <NUM> at the respective edge <NUM>, <NUM>. In some embodiments, this width <NUM> is in the range of about <NUM> to about <NUM>, and more preferably in the range of about <NUM> to about <NUM>. In the illustrated embodiment, the width <NUM> is approximately <NUM>. The teeth <NUM> are spaced equidistant from each other by respective gaps <NUM> therebetween. The gaps <NUM> each have a width <NUM> at the respective edge <NUM>, <NUM>. In some embodiments, the width <NUM> of each gap is in the range of about <NUM> to about <NUM>. In the illustrated embodiment, the width <NUM> is approximately <NUM>.

With reference to <FIG>, in one suitable embodiment the stationary blade <NUM> may be formed starting from a sheet material and removing material to form the gaps <NUM>, thus also defining the teeth <NUM>. For example, a tool (not shown) may be used to remove the material between the teeth <NUM> according to a predetermined tool depth <NUM>. In some embodiments, the tool depth <NUM> is in the range of about <NUM> to about <NUM>. In the illustrated embodiment, the tool depth <NUM> is approximately <NUM>. At the tool depth <NUM>, groove surfaces <NUM> are formed between the teeth <NUM>. These groove surfaces <NUM> incline at an angle <NUM> (<FIG>) relative to the cutting plane <NUM> from the lower surface <NUM> to the respective angled upper surface <NUM>, <NUM>. In some embodiments, the angle <NUM> of each groove surface <NUM> is in the range of <NUM>° to about <NUM>°. In the illustrated embodiment, the angle <NUM> is approximately <NUM>°. It is understood that in other embodiments the teeth <NUM> of the stationary blade <NUM> may be formed in another suitable manner and/or to have other suitable configurations without departing from the scope of this invention.

As seen best in <FIG>, the stationary blade <NUM> is configured to further have a cavity <NUM> in the lower surface opposite the upper surface <NUM> of the middle portion <NUM> of the blade. The cavity <NUM> spans the middle portion and further extends into the first and second transverse edge portions <NUM>, <NUM>. The cavity <NUM> is configured to receive mounting components for connecting the stationary blade <NUM> to the head <NUM>. As shown in the illustrated embodiment, a post <NUM> extends through the movable blade <NUM> and is connected to the middle portion <NUM> of the stationary blade <NUM>. The post <NUM> may be connected to the stationary blade <NUM> in any suitable manner. For example, the post <NUM> may be welded to the stationary blade <NUM>. In the illustrated embodiment, the post <NUM> is integrally formed with the guard <NUM> and retains the blade assembly <NUM> within the guard. In other embodiments, the components of the head <NUM> may be connected to each other in any manner that enables the trimmer <NUM> to operate as described.

With reference to <FIG>, the stationary blade <NUM> may have a reduced thickness along the cavity <NUM>. For example, in the illustrated embodiment, a thickness <NUM> of the middle portion <NUM> above the cavity <NUM> is less than the distance <NUM> between the upper surface <NUM> and the cutting plane <NUM>. The depth of the cavity <NUM> is the difference between the distance <NUM> and the thickness <NUM>. In some embodiments, the distance <NUM> is in the range of about <NUM> to about <NUM>, more preferably in the range of about <NUM> to about <NUM>. In some embodiments, the thickness <NUM> is in the range of about <NUM> to about <NUM>, more preferably in the range of about <NUM> to about <NUM>. In other embodiments, the stationary blade <NUM> may have any suitable thickness. In alternative embodiments, which are not part of the currently claimed invention, the cavity <NUM> may be omitted.

Referring now to <FIG>, the movable blade <NUM> includes a first transverse edge portion <NUM>, a second transverse edge portion <NUM>, and a middle portion <NUM>. The middle portion <NUM> extends between the first transverse edge portion <NUM> and the second transverse edge portion <NUM> and is substantially planar. The first transverse edge portion <NUM> and the second transverse edge portion <NUM> extend at angles relative to the cutting plane <NUM>. Each of the first transverse edge portion <NUM> and the second transverse edge portion <NUM> includes teeth <NUM>. In other embodiments, the movable blade <NUM> may have different configurations and be within the scope of the present invention.

The movable blade <NUM> has a thickness defined between opposite surfaces of the movable blade. The thickness may be in a range from about <NUM> to about <NUM>. The thickness may vary throughout the movable blade <NUM>. For example, the movable blade <NUM> may have a maximum thickness in the middle portion <NUM> and minimum thicknesses in the teeth <NUM>. In other embodiments, the movable blade <NUM> may have a different thickness and be within the scope of the invention.

With reference now to <FIG> and <FIG>, the guard <NUM> is generally V-shaped in cross-section to generally define an interior space in which the blade assembly <NUM> is disposed upon assembly of the head <NUM>. The guard generally includes a middle portion <NUM> and transverse comb portions <NUM> disposed on opposite sides of the middle portion and corresponding generally to the first and second transverse edge portions <NUM>, <NUM> of the stationary blade <NUM>. The comb portions <NUM> each include a respective set of comb teeth <NUM> corresponding to and in proximity of the corresponding teeth <NUM> of the stationary blade <NUM> and associated teeth <NUM> of the movable blade <NUM>. In other embodiments, the guard <NUM> may have other suitable configurations without departing from the scope of the invention.

As shown in <FIG>, each comb tooth <NUM> of the guard <NUM> has a width <NUM> that is greater than width <NUM> of the stationary blade teeth <NUM> as well as the width of the movable blade teeth <NUM>. In some suitable embodiments, the width <NUM> is in the range of about <NUM> to about <NUM>, and more preferably in the range of about <NUM> to about <NUM>. The comb teeth <NUM> of the guard <NUM> are spaced equidistant from each other by suitable gaps <NUM>. In some embodiments, the gaps <NUM> have a width <NUM> in the range of about <NUM> to about <NUM>, more preferably in the range of about <NUM> to about <NUM>. In the illustrated embodiment, the guard <NUM> is configured such that the comb teeth <NUM> of the guard align with approximately every other tooth <NUM> of the movable blade <NUM>. The relatively larger spacing of the comb teeth <NUM> of the guard <NUM> allows the stationary blade <NUM> and the movable blade <NUM> to cut a greater range of hair lengths. In particular, the comb teeth <NUM> arrangement enables long hairs to enter between the teeth <NUM> and be cut by the blade assembly <NUM>.

With particular reference to <FIG>, because the guard <NUM> is generally V-shaped in cross-section, the comb portions <NUM> of the guard extend upward and outward past the edges <NUM>, <NUM> of the stationary blade at an angle <NUM> relative to the cutting plane <NUM> of the blade assembly <NUM>. In some embodiments, the angle <NUM> of the comb portions <NUM> of the guard <NUM> is in the range of about <NUM>° to about <NUM>°, and more suitably in the range of about <NUM>° to about <NUM>°. In the illustrated embodiment, the angle <NUM> is approximately <NUM>°.

Additionally, because the comb portions <NUM> of the guard <NUM> are angled in this manner, the comb portions are spaced from the respective edges <NUM>, <NUM> of the stationary blade <NUM>, e.g., to define respective spaces <NUM> extending perpendicular to the comb portions and extending from the comb portions to the respective edge <NUM>, <NUM> of the stationary blade. In some embodiments, the spaces <NUM> have a width in the range of about <NUM> to about <NUM>. In this manner, the guard <NUM> is configured to increase the comfort of the person whose hair is being trimmed. For example, the disclosed guard <NUM> configuration reduces pinching of the user's skin during trimming, e.g., while moving the trimmer over the user's face during trimming. The guard <NUM> configuration also reduces irritation of the skin that would otherwise be caused by the blades <NUM>, <NUM> directly contacting the skin. It is understood, however, that in other embodiments the guard <NUM> may be configured other than as illustrated and described herein and remain within some aspects of the present invention.

The guard <NUM> extends at least to the cutting plane <NUM>. Specifically, in the illustrated embodiment, the comb portions <NUM> of the guard <NUM> extend from the middle portion <NUM> of the guard <NUM> proximate the base of the stationary blade <NUM> to beyond the cutting plane <NUM>. At least some of the comb teeth <NUM> extend beyond the cutting plane <NUM> to accommodate flexing of the blades <NUM>, <NUM> such as in the middle of the blades. Comb teeth <NUM> located proximate the ends of the blades <NUM>, <NUM> may extend to and end at the cutting plane <NUM>. In other embodiments, the comb portions <NUM> of the guard <NUM> may extend any distance that enables the guard <NUM> to function as described.

The guard <NUM> has a thickness defined between opposite sides of the comb teeth <NUM> at the cutting plane <NUM> in a direction parallel to the cutting plane. For example, the thickness of the guard may be in a range of about <NUM> to about <NUM>. As a result, the guard <NUM> inhibits skin being pinched between or contacting the blades <NUM>, <NUM> at the cutting plane <NUM> and allows hair to be cut by the blades <NUM>, <NUM>.

In some embodiments, at least some of the comb teeth <NUM> have a thickness and/or height that is different from the thickness and/or height of other comb teeth. For example, in some embodiments, the comb teeth <NUM> extending proximate the ends of the blades <NUM>, <NUM> are thinner and shorter than the comb teeth <NUM> extending proximate the middle of the blades <NUM>, <NUM>. Accordingly, the larger comb teeth <NUM> may accommodate any flexing of the middle of the blades <NUM>, <NUM> during operation. Also, the increased size of the comb teeth <NUM> provides increased comfort and further reduces the risk skin being pinched between or contacting the blades <NUM>, <NUM> at the cutting plane <NUM>. In addition, the varying thickness and height of the comb teeth <NUM> is configured to maintain a reduced visual profile of the guard <NUM>. In some embodiments, the guard <NUM> may include at least one comb tooth <NUM> that has a thickness of at least about <NUM> or at least about <NUM> or at least about <NUM>. In some embodiments, the guard <NUM> may include at least one comb tooth <NUM> that has a thickness of no more than about <NUM>. In other embodiments, the comb teeth <NUM> may have any thickness that enables the guard <NUM> to function as described herein.

Referring now to <FIG>, a second embodiment of an electric hair grooming appliance is generally indicated at <NUM> (<FIG>), also in the form of trimmer. More specifically, the illustrated trimmer <NUM> is similar to the trimmer <NUM> of the embodiment of <FIG> in that it includes a handle, indicated generally at <NUM>, and a head (broadly, a hair grooming assembly), indicated generally at <NUM> mounted on the handle. Together the handle <NUM> and the head <NUM> generally define a longitudinal axis B-B of the trimmer <NUM>. In this embodiment, the head <NUM> is fixed, e.g., not pivotable, relative to the handle <NUM>. The head <NUM> is suitably detachable from the handle <NUM> for cleaning and/or replacement. However, it is understood that in other embodiments the head <NUM> may be affixed to handle <NUM>.

Referring to <FIG>, the head <NUM> includes a blade assembly <NUM> and a guard <NUM> configured to receive the blade assembly therein. The blade assembly <NUM> generally comprises a stationary blade <NUM> and a movable blade <NUM>. The stationary blade <NUM> includes a first transverse edge portion <NUM>, a second transverse edge portion <NUM>, and a middle portion <NUM> extending therebetween and including a generally planar upper surface <NUM>. The first transverse edge portion <NUM> includes blade teeth <NUM> defining a first edge <NUM> of the stationary blade <NUM>. The second transverse edge portion <NUM> includes blade teeth <NUM> forming a second edge <NUM> of the stationary blade <NUM>. The first transverse edge portion <NUM> includes a first upper surface <NUM> extending from the first edge <NUM> to the upper surface <NUM>, while the second transverse edge portion <NUM> includes a second upper surface <NUM> extending from the second edge <NUM> to the upper surface <NUM>. The first upper surface <NUM> and the second upper surface <NUM> extend continuously at a constant slope from the respective edges <NUM>, <NUM> to the upper surface <NUM> so that the stationary blade is beveled on both transverse sides of the middle portion <NUM>. The stationary blade <NUM> of this embodiment suitably has a length <NUM> of approximately <NUM>. In other embodiments, however, the length of the stationary blade <NUM> may be greater or less than <NUM> and remain within the scope of this invention.

As seen in <FIG>, the movable blade <NUM> includes a first transverse edge portion <NUM>, a second transverse edge portion <NUM>, and a middle portion <NUM> extending therebetween. The middle portion <NUM> extends between the first transverse edge portion <NUM> and the second transverse edge portion <NUM> and is substantially planar. In addition, the middle portion <NUM> is substantially parallel to the cutting plane <NUM> defined by the interface between the stationary blade <NUM> and the movable blade <NUM>. The first transverse edge portion <NUM> and the second transverse edge portion <NUM> are angled relative to the cutting plane <NUM>. Each of the first transverse edge portion <NUM> and the second transverse edge portion <NUM> includes a set of blade teeth <NUM>. In other embodiments, the movable blade <NUM> may have different configurations without departing from some aspects of the invention.

Referring now to <FIG>, the movable blade <NUM> is configured to contact lower surfaces <NUM> of the first and second transverse edge portions <NUM>, <NUM> of the stationary blade <NUM> as the movable blade reciprocates. The upper surface <NUM> of the middle portion of the stationary blade <NUM> is substantially parallel to the cutting plane <NUM>. In contrast, the first upper surface <NUM> and the second upper surface <NUM> of the stationary are angled relative to the cutting plane <NUM> and hence the upper surface <NUM> of the middle portion <NUM>. The lower surfaces <NUM> of the stationary blade are opposite the respective first and second upper surfaces <NUM>, <NUM> of the stationary blade. The lower surfaces <NUM> are substantially planar and parallel to the upper surface <NUM> and the cutting plane <NUM>.

In the illustrated embodiment, the stationary blade <NUM> is symmetric about a midline of the middle portion <NUM>. Accordingly, the second transverse edge portion <NUM> has dimensions that are substantially equal to the first transverse edge portion <NUM>. Therefore, the description, including dimensions, of the first transverse edge portion <NUM> may also apply to the second transverse edge portion <NUM>, and vice versa. In other embodiments, the second transverse edge portion <NUM> and the first transverse edge portion <NUM> may have some dimensions that differ. The first upper surface <NUM> defines an angle <NUM> with the cutting plane <NUM> in the range of about <NUM>° to about <NUM>°, and more preferably in the range of about <NUM>° to about <NUM>°. In the illustrated embodiment, the angle <NUM> is approximately <NUM>°.

The first transverse edge portion <NUM> extends away from the lower surface <NUM> at a constant angle from the first edge <NUM> to the middle portion <NUM>. Accordingly, the first transverse edge portion <NUM> has a varying thickness <NUM> between the first upper surface <NUM> and the lower surface <NUM>. The first transverse edge portion <NUM> has a minimum thickness <NUM> at the first edge <NUM> in the range of about <NUM> millimeters (mm) to about <NUM>. In the illustrated embodiment, the thickness <NUM> at the first edge <NUM> is approximately <NUM>.

Referring back to <FIG>, each of the first and second transverse edge portions <NUM>, <NUM> includes respective blade teeth <NUM> at least partially forming the edges <NUM>, <NUM>. Each tooth has a width <NUM> at the respective edge <NUM>, <NUM> in the range of about <NUM> to about <NUM>, and more preferably in the range of about <NUM> to about <NUM>. In the illustrated embodiment, the width <NUM> of each blade tooth <NUM> is approximately <NUM>. The teeth <NUM> are spaced by suitable gaps <NUM> having a width <NUM> at the respective edge <NUM>, <NUM> in the range of about <NUM> to about <NUM>. In the illustrated embodiment, the width <NUM> is approximately <NUM>.

With reference to <FIG>, the guard <NUM> is generally V-shaped in cross-section and includes a middle portion <NUM> and opposed comb portions <NUM> extending outward and upward from the middle portion to form an interior space for receiving the blade assembly <NUM> into the guard. The guard <NUM> is configured to receive the blade assembly <NUM> such that the comb portions <NUM> extend in proximity to but otherwise outward of the edges <NUM>, <NUM> of the stationary blade <NUM>. In particular, the comb portions <NUM> include comb teeth <NUM> that extend adjacent the stationary blade teeth <NUM> and the movable blade teeth <NUM>. In other embodiments, the guard <NUM> may have other configurations without departing from some aspects of the invention.

As shown in <FIG>, each comb tooth <NUM> has a width <NUM> that is greater than the respective widths of the stationary blade teeth <NUM> and the movable blade teeth <NUM>. In some embodiments, the width <NUM> of each comb tooth is in the range of about <NUM> to about <NUM>, more preferably in the range of about <NUM> to about <NUM>. The comb teeth are suitably spaced from each by gaps <NUM> each having a gap width <NUM> in the range of about <NUM> to about <NUM>, and more preferably in the range of about <NUM> to about <NUM>. In the illustrated embodiment, the comb teeth <NUM> and gap width <NUM> is such that two stationary blade teeth <NUM> are capable of positioning between each adjacent pair of comb teeth <NUM>.

With reference to <FIG>, the comb portion <NUM> extends past the blade assembly <NUM> at an angle <NUM> relative to the cutting plane <NUM>. In some embodiments, the angle <NUM> is in the range of about <NUM>° to about <NUM>°, and more preferably in the range of about <NUM>° to about <NUM>°. The comb portions <NUM> are spaced from the respective edges <NUM>, <NUM> of the stationary blade <NUM> to define spaces <NUM> therebetween on opposite sides of the stationary blade <NUM> - as determined perpendicular to the comb portion and extending from the comb portion to the respective edge of the stationary blade. In some embodiments, each space <NUM> has a width in the range of about <NUM> to about <NUM>.

Referring now to <FIG>, an embodiment of a head for use with hair grooming appliance <NUM> (shown in <FIG>) and hair grooming appliance <NUM> (shown in <FIG>) is generally indicated at <NUM> (<FIG>). The head <NUM> includes a blade assembly <NUM> and a guard <NUM> configured to receive the blade assembly therein. The blade assembly <NUM> generally comprises a stationary blade <NUM> and a movable blade <NUM> (<FIG>). The head <NUM> may have other configurations without departing from some aspects of this invention.

The stationary blade <NUM> has a varying thickness and is configured to allow the blade assembly <NUM> to cut hairs close to a user's skin. In addition, the stationary blade <NUM> is configured to reduce irritation to the skin during operation. For example, the thick portions of the stationary blade <NUM> prevent flexing of the stationary blade <NUM> during operation. The thin portions of the stationary blade <NUM> facilitate the blade assembly <NUM> cutting hairs close to the skin.

With reference to <FIG>, the stationary blade <NUM> includes a first transverse edge portion <NUM>, a second transverse edge portion <NUM>, and a middle portion <NUM> extending therebetween and including a generally planar upper surface <NUM>. The first transverse edge portion <NUM> includes blade teeth <NUM> forming a first edge <NUM> of the stationary blade <NUM>. The second transverse edge portion <NUM> includes blade teeth <NUM> forming a second edge <NUM> of the stationary blade <NUM>. The stationary blade <NUM> of this embodiment suitably has a transversely extending length <NUM> of approximately <NUM>. In other embodiments, however, the length of the stationary blade <NUM> may be greater or less than <NUM> and remain within the scope of this invention.

The first transverse edge portion <NUM> includes a first upper surface <NUM> and a first curved upper surface <NUM>. The first upper surface <NUM> extends from the planar upper surface <NUM> to the first curved upper surface <NUM>. The first curved upper surface <NUM> extends from the first upper surface <NUM> to the first edge <NUM>.

The second transverse edge portion <NUM> includes a second upper surface <NUM> and a second curved upper surface <NUM>. The second upper surface <NUM> extends from the upper surface <NUM> to the second curved upper surface <NUM>. The second curved upper surface <NUM> extends from the second upper surface <NUM> to the second edge <NUM>.

As shown in <FIG>, the first curved upper surface <NUM> and the second curved upper surface <NUM> are concave and curve towards planar lower surfaces <NUM> of the stationary blade <NUM>. Accordingly, the stationary blade <NUM> has a reduced thickness along the first curved upper surface <NUM> and the second curved upper surface <NUM>. In particular, the stationary blade <NUM> has a minimum thickness <NUM> defined between each curved upper surface <NUM>, <NUM> and the respective planar lower surface <NUM> of the stationary blade <NUM>. The planar lower surfaces <NUM> are configured to contact the movable blade <NUM>. In some embodiments, the minimum thickness <NUM> is in a range of about <NUM> to about <NUM>. In this embodiment, the minimum thickness <NUM> is approximately <NUM>.

The first curved upper surface <NUM> and the second curved upper surface <NUM> each have a radius <NUM>. Each radius <NUM> may be any suitable radius that enables the stationary blade to function as described herein.

The first edge <NUM> and the second edge <NUM> of the stationary blade <NUM> are located a distance <NUM> from edges <NUM> of the movable blade <NUM>. The distance <NUM> is measured along a cutting plane <NUM> of the blade assembly <NUM>. The distance <NUM> prevents the movable blade <NUM> contacting the user's skin during operation. In some embodiments, the distance <NUM> is in a range of about <NUM> to about <NUM>. In this embodiment, the distance <NUM> is approximately <NUM>.

The stationary blade <NUM> has a tip thickness <NUM> at the first edge <NUM> and the second edge <NUM>. The concave curves of the first curved upper surface <NUM> and the second curved upper surface <NUM> allow the tip thickness <NUM> to be greater than the minimum thickness <NUM>. The tip thickness <NUM> allows for laser ball tips to be incorporated into stationary blade <NUM>. In some embodiments, the tip thickness <NUM> is in a range of about <NUM> to about <NUM>. In this embodiment, the tip thickness <NUM> is approximately <NUM> without laser ball tips and approximately <NUM> including laser ball tips. In other embodiments, the stationary blade <NUM> may have other tips without departing from some aspects of this invention.

The following embodiments are not according to the claimed invention and are shown for illustrative purposes only.

In some embodiments, a trimmer includes a handle, a drive assembly in the handle, and a head attached to the handle. The head includes a stationary blade including a first transverse edge portion, a second transverse edge portion, and a middle portion connecting the first transverse edge portion and the second transverse edge portion. The first transverse edge portion includes blade teeth defining a first edge of the blade. The second transverse edge portion includes blade teeth defining a second edge of the blade. The first transverse edge portion further includes a first upper surface extending from the first edge to the middle portion and the second transverse edge portion further includes a second upper surface extending from the second edge to the upper surface of the middle portion. The first upper surface includes at least one of an angled surface, a concave surface, and a convex surface along at least a portion of the extension of the first upper surface between the middle portion and the first edge. The head also includes a movable blade in shearing contact with the first transverse edge portion and the second transverse edge portion of the stationary blade. The drive assembly is configured to reciprocate the movable blade relative to the stationary blade.

In one such embodiment, the second upper surface includes at least one of an angled surface, a concave curve, and a convex curve extending along at least a portion of the extension of the second upper surface between the middle portion and the first edge.

In another such embodiment, the middle portion includes a substantially planar upper surface extending between the first upper surface and the second upper surface.

In yet another such embodiment, the stationary blade and the movable blade are in contact with each other to define a cutting plane that is substantially planar and parallel to the upper surface of the middle portion of the stationary blade.

In another such embodiment, the first upper surface is angled relative to the cutting plane.

In yet another such embodiment, an angle between the first upper surface and the cutting plane is in the range of about <NUM>° to about <NUM>°.

In another such embodiment, the angle between the first upper surface and the cutting plane is in the range of about <NUM>° to about <NUM>°.

In yet another such embodiment, the stationary blade has a thickness at the first edge in a range of about <NUM> millimeters (mm) to about <NUM>.

In yet another such embodiment, the thickness of the stationary blade at the first edge is approximately <NUM>.

In yet another such embodiment, the first upper surface includes a curve extending along a portion of the extension of the first upper surface between the middle portion and the first edge.

In yet another such embodiment, the second upper surface includes a curve extending along a portion of the extension of the second upper surface between the middle portion and the second edge.

In yet another such embodiment, the stationary blade has a minimum thickness defined by the first upper surface in a range of about <NUM> to about <NUM>.

In yet another such embodiment, the stationary blade has a tip thickness in a range of about <NUM> to about <NUM>.

In yet another such embodiment, the first upper surface includes a concave curve.

In other embodiments, a trimmer includes a handle, a drive assembly in the handle, and a blade assembly configured for operative connection to the drive assembly. The blade assembly includes a stationary blade including blade teeth. Each blade tooth has a width. The blade assembly also includes a movable blade including blade teeth. The drive assembly is operable to reciprocate the movable blade relative to the stationary blade. The blade assembly further includes a guard disposed outward of and extending in proximity to the respective blade teeth of the stationary blade and movable blade. The guard includes comb teeth. Each comb tooth has a width that is greater than the width of each stationary blade tooth.

In one such embodiment, the stationary blade and the movable blade together define a cutting plane. The guard extends at least to the cutting plane.

In another such embodiment, the guard and the stationary blade define a gap therebetween at the cutting plane in a range of about <NUM> to about <NUM>.

In yet another such embodiment, the blade assembly is pivotably connected to the handle.

In yet another such embodiment, the width of each blade tooth of the stationary blade is in the range of about <NUM> to about <NUM>.

In yet another such embodiment, the blade teeth of the stationary blade are spaced by gaps having a width in the range of about <NUM> to about <NUM>.

In yet another such embodiment, the width of each comb tooth is in the range of about <NUM> to about <NUM>.

In yet another such embodiment, the comb teeth of the guard are spaced by gaps. Each gap has a width in the range of about <NUM> to about <NUM>.

In other embodiments, a hair grooming appliance includes a handle, a drive assembly in the handle, and a head attached to the handle. The head includes a blade assembly including a stationary blade and a movable blade. The drive assembly is operable to reciprocate the movable blade relative to the stationary blade. Each of the stationary blade and the movable blade includes respective blade teeth. The blade teeth of the stationary blade teeth define a first blade edge and a second blade edge of the stationary blade. The stationary blade includes a first transverse edge portion, a second transverse edge portion, and a middle portion extending therebetween. The first transverse edge portion has a first upper surface extending from the first edge of the stationary blade to the middle portion. The second transverse edge portion includes a second upper surface extending from the second edge of the stationary blade to the middle portion. The first upper surface includes at least one of an angled surface, a concave surface, and a convex surface along at least a portion of the extension of the first upper surface between the middle portion and the first edge. The second upper surface includes at least one of an angled surface, a concave surface, and a convex surface along at least a portion of the extension of the second upper surface between the middle portion and the second edge. The head also includes a guard configured to receive the blade assembly therein and having opposed comb portions disposed in proximity to the first and second edges of the stationary blade. Each of the comb portions has comb teeth.

In one such embodiment, the stationary blade and the movable blade define a cutting plane therebetween. An angle between the first upper surface and the cutting plane is in the range of about <NUM>° to about <NUM>°.

In another such embodiment, the blade teeth of the stationary blade each have a width. Each comb tooth has a width that is greater than the width of each blade tooth of the stationary blade.

In yet another such embodiment, the comb portions of the guard are spaced from the first and second edges of the stationary blade in the range of about <NUM> to about <NUM> as determined perpendicular to the respective comb portion.

In yet another such embodiment, the head is pivotably attached to the handle.

As described above, embodiments of a trimmer include a blade that includes at least one beveled edge. In some embodiments, the blade is a double-edged blade and includes two beveled edges. The beveled edges allow the blade to be sharper than conventional blades while also being more durable than at least some known blades. Accordingly, the blade may have a longer service life. Moreover, in some embodiments, the trimmer may cost less to assemble than at least some known trimmers.

In addition, embodiments of the trimmer include a blade including a curved or recessed surface along the beveled edge. The curved surface allows the blade to be thinner adjacent cutting edges of a movable blade to provide a closer trim. In addition, the blade includes relatively thick portions that resist flexing of the blade. Moreover, in some embodiments, the curved surface is concave and allows the blade to have thicker tips.

In addition, embodiments of the trimmer include a guard having comb teeth in spaced proximity to the blade assembly. The guard protects the skin of a person as the trimmer is moved along the skin. In addition, the guard allows the blade assembly to cut a greater range of hairs.

Exemplary embodiments of an apparatus, system, and methods for a hair grooming appliance are described above in detail. The apparatus, system, and methods described herein are not limited to the specific embodiments described, but rather, components of apparatus, systems, and/or steps of the methods may be utilized independently and separately from other components and/or steps described herein. For example, the methods may also be used in combination with other hair grooming appliances, systems, and methods, and are not limited to practice with only the apparatuses, systems, and methods described herein. Rather, the exemplary embodiments can be implemented and utilized in connection with many grooming applications.

Claim 1:
A head (<NUM>) for an electric handheld hair trimmer (<NUM>), the head (<NUM>) comprising:
a blade assembly (<NUM>) comprising:
(i) a stationary blade (<NUM>) including:
a first transverse edge portion (<NUM>) including a first upper surface (<NUM>) and blade teeth (<NUM>), the blade teeth defining a first edge (<NUM>) of the stationary blade;
a second transverse edge portion (<NUM>) including a second upper surface (<NUM>) and blade teeth (<NUM>), the blade teeth defining a second edge (<NUM>) of the stationary blade; and
a middle portion (<NUM>) connecting the first transverse edge portion and the second transverse edge portion, wherein the middle portion includes a substantially planar upper surface (<NUM>) extending between the first upper surface and the second upper surface, a lower surface opposite the planar upper surface, and a cavity (<NUM>) in the lower surface,
wherein the cavity (<NUM>) spans the middle portion and further extends into the first and second transverse edge portions (<NUM>, <NUM>),
the first upper surface extending from the first edge to the middle portion, the second upper surface extending from the second edge to the middle portion, the first transverse edge portion and the second transverse edge portion being beveled from the middle portion to the respective edges of the stationary blade, wherein the stationary blade is symmetric about a midline of the middle portion; and
(ii) a movable blade (<NUM>) in shearing contact with the first transverse edge portion and the second transverse edge portion of the stationary blade; and
the head (<NUM>) further comprising a mounting component connected to the middle portion of the stationary blade for connecting the stationary blade to the head (<NUM>), wherein the mounting component comprises a post (<NUM>) extending through the movable blade and received in the cavity in the lower surface, characterised in that the post (<NUM>) is fixedly connected to the lower surface of the middle portion of the stationary blade.