Patent Description:
<CIT> describes a cutting device and a hair-cutting apparatus with two toothed blades arranged to be moveable with respect to each other are proposed, the cutting device comprising magnetic means arranged to press both blades together.

<CIT> describes a clipper blade that fits on a clipper comb and is moved so as to oscillate via a driver fastened on a driver side. An element applies cutting pressure in the form of magnets. A guiding metal sheet fits between the clipper comb and the clipper blade.

In a first aspect of the invention there is provided a magnetic blade assembly according to independent claim <NUM>.

Optional and/or preferable features are laid out in the dependent claims.

This application will become more fully understood from the following detailed description, taken in conjunction with the accompanying figures, wherein like reference numerals refer to like elements in which:.

Referring generally to the figures, various embodiments of hair cutters or clippers are shown. The cutters include a blade assembly with an upper or inner blade that oscillates over a lower or outer blade to cut or trim hair. The alignment or gap of an edge of the inner blade relative to an edge of the outer blade affects the cut hair length. For example, if the outer blade has a surface that decreases along the length of the blade, moving the inner blade relative to the outer blade will change the length of hair that is cut. In order to adjust the gap created between the cutting end of the teeth on the inner blade and the cutting end of the teeth on the outer blade an adjustment slider or selector mechanism couples to the inner blade and moves the cutting end of the inner blade relative to the outer blade. This movement extracts or retracts the blades, which enlarges or diminishes a gap between the cutting ends of the inner and outer blades. Controlling the size of the gap enables an operator to adjust the desired cut length that the clippers will cut hair.

Proper tensioning between the blades reduces friction on the system, wear and tear on the blades, and enhances the operational life of the motor. The inner and outer blade should be tensioned/pulled together so that the oscillation of the inner and outer teeth do not interfere with the cutting ends of the blades. A guide member such as a T-guide that is formed by including an arm on the inner blade enables the inner and outer blades to oscillate while retaining the desired tensile force (e.g., with a spring or other biasing mechanism).

Applicant has found that using a magnetic force to generate a tensioning force between the inner and outer blades reduces friction between the blades, which reduces load on the motor and improves overall efficiency of the system. For example, a guide member situated between the upper and the lower blade (e.g., inner and outer blade) is magnetized, includes magnets, or includes an electromagnetic system that creates an attractive force between the blades and reduces the friction of oscillation of the inner blade. In some embodiments, the system detects the load or speed of the motor or blades and increases or decreases the electromagnetic attractive force to minimize the load.

Combining the T-guide with a guide rail or cross-portion and arm or body having a diagonal slot mechanism enables the operator to select a gap between the cutting edges of the inner and outer blades to cut hair at a desired length. This configuration enables the operator to selectively adjust the blade set before, during, or after operation. The operator is able to select the relative closeness of the cut without having to detach the blade set and realign the blades manually. Pre-set detents within the diagonal slot or along the adjustment slider form predetermined gaps associated with desirable cut lengths. The adjustment slider moves between the detents to a selected and fixed hair cutting length (e.g., a predetermined length of cut).

For ease of discussion and understanding, the following detailed description will refer to and illustrate the blade assembly that incorporates magnetic tensioning and/or blade set adjustment in association with a hair cutting apparatus or "cutter. " It should be appreciated that a "cutter" is provided for purposes of illustration, and the blade assembly disclosed herein can be used in association with any hair cutting, hair trimming, or hair grooming device. Accordingly, the term "cutter" is inclusive, and refers to any hair grooming device including, but not limited to, a hair trimmer, a hair clipper, or any other hair cutting or hair grooming device. The cutter device can be suitable for a human, animal, or any other living or inanimate object having hair.

<FIG> illustrates an example embodiment of a hair cutting apparatus, trimmer, clipper, or cutter <NUM>. Cutter <NUM> includes a body <NUM>, a blade set or blade assembly <NUM>, and a drive assembly <NUM>. As illustrated in <FIG>, body <NUM> is hand-held and includes a clamshell configuration of two portions: a first or upper housing <NUM> and a second or lower housing <NUM> (e.g., on a top and bottom of cutter <NUM>). Cutter <NUM> body <NUM> may include other configurations. For example upper housing <NUM> and/or lower housing <NUM> form a single integral body <NUM> or component part. Body <NUM> could join housing <NUM> and/or housing <NUM> in other clamshell configurations (e.g., from one or more sides) and may include additional parts on the top, bottom, sides, or ends of body <NUM>. Blade assembly <NUM> includes a translating, upper, or inner blade <NUM> and a stationary, lower, or outer blade <NUM>. Body <NUM> and housing <NUM> and/or <NUM> define a cutting end <NUM> that includes blade assembly <NUM>. Body <NUM> further defines a cavity <NUM> to support a motor <NUM>. As illustrated in <FIG>, cavity <NUM> is formed from a clamshell configuration of upper housing <NUM> and lower housing <NUM> such that body <NUM> surrounds drive assembly <NUM> and motor <NUM> coupled to blade assembly <NUM>.

Drive assembly <NUM> is positioned within cavity <NUM> and couples blade assembly <NUM> to motor <NUM>. As illustrated, motor <NUM> is a rotary DC electric motor <NUM>. In other embodiments, motor <NUM> is a pivot motor or a magnetic motor <NUM> that generates oscillating or reciprocating movement for blade assembly <NUM>. In other embodiments, motor <NUM> is an AC electric motor or any other suitable motor for generating oscillating or reciprocating movement for a blade assembly <NUM>, e.g., inner blade <NUM> and/or outer blade <NUM>. As illustrated, motor <NUM> is configured to operate on battery power (e.g., cordless), but may be configured to operate with electricity from any suitable electric source, e.g., a corded cutter <NUM> plugged into an outlet.

Motor <NUM> couples to a rotating motor output shaft <NUM> that rotates about a rotational axis. An eccentric drive <NUM> is coupled to motor output shaft <NUM> and rotates eccentrically about the rotational axis. Eccentric drive <NUM> includes an eccentric shaft <NUM> that is offset from motor output shaft <NUM>. In other words, eccentric shaft <NUM> is offset from the axis of rotation of motor <NUM>, such that eccentric shaft <NUM> rotates non-concentrically around the axis of rotation to create an oscillatory rotational motion. Eccentric shaft <NUM> is configured to engage a yoke <NUM> (<FIG>) of blade assembly <NUM> and translate or oscillate inner blade <NUM> linearly. Blade assembly <NUM> is coupled to cutting end <NUM> of the body <NUM>. For example blade assembly <NUM> may couple to body <NUM> with an adhesive, a rivet, a weld, a bolt, a screw, or at least one fastener.

<FIG> illustrates a perspective view of blade assembly <NUM>. Blade assembly <NUM> includes inner blade <NUM> and outer blade <NUM>. In the illustrated embodiment, outer blade <NUM> does not oscillate and is fixed relative to body <NUM>, such that inner blade <NUM> is configured to oscillate, reciprocate, or slide relative to outer blade <NUM> to facilitate cutting. Inner blade <NUM> oscillates over outer blade <NUM> to create a cutting blade assembly <NUM> capable of cutting hair.

Blade assembly <NUM> includes an adjustment gap assembly, mechanism, or slider <NUM> that translates inner blade <NUM> over outer blade <NUM> in a direction that is transverse to the oscillatory motion of inner blade <NUM>. Translation of inner blade <NUM> in this transverse direction changes the cut-length during operation of cutter <NUM>. Spring retainer <NUM> couples to inner blade <NUM> via a spring <NUM>. Spring retainer <NUM> is fixedly attached to outer blade <NUM> (e.g., by fasteners <NUM>). Spring <NUM> interconnects spring retainer <NUM> to yoke <NUM> and permits yoke <NUM> to oscillate from the rotational output of eccentric shaft <NUM>.

Yoke <NUM> is coupled to inner blade <NUM> and to eccentric shaft <NUM>, which is coupled to motor <NUM>. Yoke <NUM> oscillates inner blade <NUM> over outer blade <NUM> based on the rotational output of motor <NUM> through eccentric shaft <NUM>. In other words, spring retainer <NUM> fixedly couples to outer blade <NUM> and connects to yoke <NUM> via spring <NUM> to allow translation of yoke <NUM> relative to spring retainer <NUM>. Yoke <NUM> is fixedly coupled to inner blade <NUM> and receives motor <NUM> output through eccentric shaft <NUM>. The eccentric rotation of eccentric shaft <NUM> oscillates inner blade <NUM> over outer blade <NUM>. With reference to <FIG> and <FIG>, as motor <NUM> rotates, motor output shaft <NUM> rotates eccentric drive <NUM> coupled to eccentric shaft <NUM>. As eccentric shaft <NUM> rotates within yoke <NUM>, inner blade <NUM> oscillates over outer blade <NUM>. As illustrated in <FIG>, a selector mechanism or adjustment slider <NUM> slidably couples along a rear edge of outer blade <NUM>. Operating slider <NUM> changes the orientation of inner blade <NUM> with respect to outer blade <NUM> in a direction orthogonal to the oscillatory motion of inner blade <NUM>. In various embodiments, slider <NUM> is powered manually or electronically (e.g., by a motor).

<FIG> is an exploded view of the blade assembly <NUM> illustrated in <FIG>. A blade guide assembly, guide member, or T-guide <NUM> interconnects inner blade <NUM> to slider <NUM>. T-guide <NUM> maintains a relative position of inner blade edge <NUM> relative to outer blade edge <NUM>. In other words, T-guide <NUM> is coupled to both inner blade <NUM> and slider <NUM>. T-guide <NUM> converts translation of slider <NUM> along the rear edge of outer blade <NUM> to translation of inner blade <NUM> in a direction that is transverse to the oscillatory motion of inner blade <NUM>. T-guide <NUM> includes an angled edge <NUM> that fits inside slider <NUM>. Angled edge <NUM> is angled so that the motion of slider <NUM> along the outer rear edge of outer blade <NUM> causes T-guide <NUM> to push or pull inner blade <NUM> along the top surface of outer blade <NUM>. In this way, T-guide <NUM> extends or retracts inner blade <NUM> relative to outer blade <NUM>.

In some embodiments, outer blade <NUM> includes a track, slot, or recess <NUM> for T-guide <NUM>. Recess <NUM> captures T-guide between inner blade <NUM> and outer blade <NUM> and directs T-guide <NUM> along recess <NUM> to translate inner blade <NUM> relative to outer blade <NUM> in a direction transverse to the sliding motion of slider <NUM> along the rear edge of outer blade <NUM>.

One or more fasteners <NUM> fixedly couple outer blade <NUM> to spring retainer <NUM> and/or body <NUM> (<FIG>). In the illustrated embodiment, two fasteners <NUM> on either side of outer blade <NUM> fixedly attach outer blade <NUM> to spring retainer <NUM> so that outer blade <NUM> does not oscillate and/or is stationary relative to the oscillatory and transverse translations of inner blade <NUM>. In this configuration, outer blade <NUM> is said to be fixed, stationary, or non-moving. In some embodiments, inner blade <NUM> moves relative to outer blade <NUM>, such that inner and/or outer blades <NUM> and <NUM> translate and/or oscillate. Inner blade <NUM> oscillates in one direction relative to outer blade <NUM> to facilitate cutting hair and translates in an orthogonal or transverse direction to change the cutting length of cutters <NUM> when an operator adjusts slider <NUM>.

<FIG> shows spring retainer <NUM> in a top perspective view. This view illustrates the connection of spring <NUM> coupled to spring retainer <NUM> in an exemplary embodiment. Similarly spring <NUM> ends couple to yoke <NUM>. Thus spring <NUM> biases yoke <NUM> to a neutral resting position as inner blade <NUM> oscillates in response to the output from motor <NUM>.

<FIG> is a bottom perspective of an underside of spring retainer <NUM>, according to an exemplary embodiment. Spring retainer <NUM> includes a plurality of ridges <NUM> inside a pair of pockets <NUM> on the rear (e.g., opposite cutting end <NUM>) of spring retainer <NUM>. Pockets <NUM> receive both ends (e.g., either side) of slider <NUM>. Ridges <NUM> slideably attach to slider <NUM> ends, such that slider <NUM> can slide or translate within pockets <NUM>. Ridges <NUM> within pockets <NUM> releasably retain and/or lock slider <NUM> within the detents formed by ridge <NUM>. In this way, ridges <NUM> enable translation and retention of slider <NUM> along the rear edge of outer blade <NUM>. Thus, translation of slider <NUM> along the rear edge of outer blade <NUM> extends or retracts inner blade <NUM> to control the cutting length. Spring retainer <NUM> includes fastener holes <NUM> to receive fasteners <NUM> (<FIG>) and fixedly couple spring retainer <NUM> to outer blade <NUM>.

<FIG> is an isolated top perspective view of blade assembly <NUM>, where structures of blade assembly <NUM> have been removed to clearly illustrate the interactions of inner blade <NUM>, outer blade <NUM>, slider <NUM>, and T-guide <NUM>. Inner blade <NUM> includes inner blade teeth <NUM>. Outer blade <NUM> includes outer blade teeth <NUM>. The shape of outer blade <NUM> may be convex so that translating inner blade <NUM> over the outer blade increases the cut-length of cutters <NUM>. For example, inner and/or outer blade teeth <NUM> and/or <NUM> are thinner at a tip of the teeth <NUM> and thicker at a root or base of teeth <NUM>.

Flanges <NUM> extend from either side of slider <NUM> and include a projection (detent) that fits within detents of ridges <NUM> (<FIG>). As described above with reference to <FIG>, flanges <NUM> slide within pockets <NUM> of spring retainer <NUM>. Flanges <NUM> are retained by detents formed by ridges <NUM>, temporarily retaining slider <NUM>. In this way, the cut-length of cutters <NUM> is held constant during operation. Slider <NUM> further includes gripping formations <NUM>. Gripping formations <NUM> may be disposed on a top, bottom, and/or side of slider <NUM> and facilitate clasping and sliding slider <NUM> along the rear edge of outer blade <NUM>. T-guide <NUM> includes a base, extension body, or arm <NUM> that connects the sliding translation of a cross-portion or guide rail <NUM> (<FIG>) to a ridge under inner blade <NUM>. Guide rail <NUM> of T-guide <NUM> has a top side adjacent to inner blade <NUM> and a bottom side adjacent to outer blade <NUM>. A pair of fastener holes <NUM> permit fasteners <NUM> to pass through outer blade <NUM> and fixedly couple outer blade <NUM> to spring retainer <NUM> and/or body <NUM>.

<FIG> is an isolated top view of the blade assembly <NUM> of <FIG>. Inner blade <NUM> has inner blade teeth <NUM> that cooperatively oscillate over outer blade teeth <NUM> of outer blade <NUM> to cut hair. As shown in <FIG> and <FIG>, the tips of inner blade teeth <NUM> are recessed. That is, tips of inner blade teeth <NUM> are not aligned with tips of outer blade teeth <NUM>. T-guide <NUM> is shown under inner blade <NUM> in ghost lines and couples to inner blade <NUM> under a ridge.

As slider <NUM> translates in a first or oscillatory direction <NUM> (e.g., left and right), inner blade <NUM> translates in a second or transverse direction <NUM> (e.g., forward and back). As shown, the translation along transverse direction <NUM> can be orthogonal to the oscillatory direction <NUM>, but it may also include translations in other non-orthogonal directions. Elongated body or arm <NUM> ensures that translation of slider <NUM> in the oscillatory direction <NUM> translates inner blade <NUM> and inner blade edge <NUM> in the transverse direction <NUM> to increase or decrease a distance (or gap) to outer blade edge <NUM>.

In some embodiments, a diagonal slot mechanism (e.g., arm <NUM> in slider <NUM>) is coupled to the base or elongated arm <NUM> of T-guide <NUM>, such that movement of slider <NUM> in a direction parallel to the inner and/or outer blade edges <NUM> and/or <NUM> moves the guide rail <NUM> in a direction perpendicular to inner and/or outer blade edges <NUM> and/or <NUM>. In other words, slider <NUM> and channel <NUM> create a diagonal joint between arm <NUM> and guide rail <NUM>.

Elongated arm <NUM> interconnects a cross-member or guide rail <NUM> (captured between inner and outer blades <NUM> and <NUM>) of T-guide <NUM> to slider <NUM>. Guide rail <NUM> is illustrated in <FIG> in ghost lines within slider <NUM>. A channel <NUM> disposed within slider <NUM> that pushes or pulls on angled edge <NUM> as slider <NUM> slides along the rear of outer blade <NUM>. Because channel <NUM> is located within slider <NUM>, channel <NUM> is also illustrated in ghost lines. Angled edge <NUM> and channel <NUM> are slidably coupled, such that when slider <NUM> translates in a first or oscillatory direction <NUM>, channel <NUM> pushes or pulls on angled edge <NUM> within slider <NUM>. Moving slider <NUM> in the oscillatory direction <NUM> extends or retracts the guide rail <NUM> of T-guide <NUM>, which is coupled to inner blade <NUM>, in a second or transverse direction <NUM>. This extends or retracts inner blade <NUM> in the transverse direction <NUM> and controls the cut length of cutters <NUM>.

In some embodiments, guide rail <NUM> includes a magnetic tension assembly <NUM>. For example, guide rail <NUM> is a ferromagnetic material that is magnetized. In other embodiments, guide rail <NUM> includes one or more magnets <NUM> and/or another electromagnetic device (e.g., windings). The magnetic tension assembly <NUM> and/or magnets <NUM> generate an attractive (e.g., tensile) force between the blade guide assembly or T-guide <NUM> and inner <NUM> and/or outer <NUM> blades. In some embodiments, the force is repulsive. In some embodiments, the magnetic tensile force between guide rail <NUM>, inner and/or outer blades <NUM> and/or <NUM> is adjustable.

In some embodiments, inner blade <NUM>, outer blade <NUM>, yoke <NUM>, and/or T-guide <NUM> are magnetized to create an attractive or repulsive force between inner blade <NUM> and outer blade <NUM>. In some embodiments, the magnetic assembly is located on at least one of a yoke <NUM>, the inner blade <NUM>, the outer blade <NUM>, or the T-guide <NUM>. In other words, inner blade <NUM>, outer blade <NUM>, yoke <NUM>, T-guide <NUM>, and/or any combination thereof, creates a magnetic field to adjust or control a tensile force (attractive or repulsive) between inner and outer blades <NUM> and <NUM>. For example, a magnetized yoke <NUM> is a non-conductive magnet carrier (e.g., a plastic yoke <NUM> carrying a ferrous magnet <NUM>) or conductive magnetic material. In some embodiments, a compounding force is generated from a plurality of magnets <NUM> with relatively weaker magnetic forces to create a compounded magnetic force from the plurality of magnets <NUM>. A variety of magnets may be used and may reduce the total cost of the magnetic assembly. In addition, using a magnetic force to control the force between blades <NUM> and <NUM> creates a reliable and efficient method to control the tensile force generated to maintain the friction between blades <NUM> and <NUM> while cutting hair.

<FIG> shows ridges <NUM> in cross-section with the remainder of spring retainer <NUM> removed. This view illustrates the interaction between flanges <NUM> on slider <NUM> with the ridges <NUM> of spring retainer <NUM>. Flanges <NUM> releasably lock within detents formed on ridges <NUM> to prevent unwanted movement of slider <NUM> during operation. However, the interaction of flanges <NUM> and ridges <NUM> is released when an operator slides slider <NUM>.

<FIG> illustrate inner blade <NUM> and outer blade <NUM> in various configurations that illustrate how slider <NUM> moves inner blade <NUM> relative to outer blade <NUM>. Inner blade <NUM> includes a plurality of inner blade teeth <NUM>. Inner blade teeth <NUM> extend along an inner blade edge <NUM>. The inner blade edge <NUM> is defined by an imaginary line connecting the tips of inner blade teeth <NUM>. Similarly, an outer blade edge <NUM> is defined by an imaginary line connecting the tips of outer blade teeth <NUM>. Inner blade <NUM> is positioned on top (or sits on top) of outer blade <NUM>, with inner blade edge <NUM> being parallel to and, in some embodiments, offset from outer blade edge <NUM>. In operation inner and outer blade edges <NUM> and <NUM> oscillate relative to each other. The distance between the imaginary line formed along inner blade edge <NUM> and the imaginary line formed along outer blade edge <NUM> is defined as a blade gap <NUM>.

Movement of slider <NUM> translates inner blade <NUM> relative to outer blade <NUM>, which changes the placement of eccentric shaft <NUM> within yoke <NUM>. Yoke <NUM> is configured to receive eccentric shaft <NUM> on drive assembly <NUM> to oscillate inner blade <NUM> at any blade gap <NUM>. As illustrated in <FIG>, three positions or configurations of inner blade <NUM> relative to outer blade <NUM> are shown, specifically "fine," "medium," and "deep" configurations. For example, three configurations that represent a fine gap, a medium gap that is greater than the fine gap, and a long gap that is greater than either the fine gap or the medium gap between inner blade edge <NUM> relative to outer blade edge <NUM>. Additional preset configurations may generate more intermediate gaps and/or cut lengths. Slider <NUM> may adjust between two or more predetermined blade gap <NUM> between inner and outer blade edges <NUM> and <NUM>. For example, slider <NUM> may include <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or more gradations or predetermined configurations.

Slider <NUM> may include words or inscriptions (e.g., "deep" and "fine") and tactile and/or visual indicators to indicate which configuration of slider <NUM> results in a longer "deep" or shorter "fine" cut. For example, a single bump on one side (e.g., "fine") and two or more bumps (e.g., "deep") on an opposite side of slider <NUM> provides both visual and tactile indication of blade gap <NUM> in either configuration. Similarly, short lines on one side and long lines on an opposite side of slider <NUM> provide visual and/or tactile indication of a cut length in the slider <NUM> position.

<FIG> illustrates a first fully extracted inner blade <NUM> with slider <NUM> in a "fine" cut configuration. This position is referred to as the aligned position because inner blade edge <NUM> and outer blade edge <NUM> are collinear. In this configuration, inner blade <NUM> is aligned with outer blade <NUM>, such that inner blade edge <NUM> of inner blade teeth <NUM> is aligned with outer blade edge <NUM> of outer blade teeth <NUM>. Because of this alignment no blade gap <NUM>, or a relatively small blade gap <NUM>, exists between inner blade edge <NUM> and outer blade edge <NUM>.

As shown, slider <NUM> is not centered on outer blade <NUM>, but is located nearer to a first fastener hole <NUM> (on the left) than to a second fastener hole <NUM> (on the right). In other words, slider <NUM> is located on a first side (e.g., left of center) along the edge of outer blade <NUM> and extends T-guide <NUM> a maximum distance. This outer blade edge <NUM> configuration places outer blade edge <NUM> near inner blade edge <NUM> to create a small or non-existent blade gap <NUM>. The result is that inner blade edge <NUM> fully extends and/or aligns with outer blade edge <NUM> and produces a short or "fine" cutting length.

As shown in <FIG>, the left flange <NUM> is further extended along ridge <NUM> than the opposite right flange <NUM> relative to ridge <NUM>. Stated differently, the left ridge <NUM> is almost entirely within the left flange <NUM> and the right ridge <NUM> is almost fully extended within the right flange <NUM> of slider <NUM>. In this configuration, channel <NUM> is pushing guide rail <NUM> a maximum distance resulting in a full extension of inner blade teeth <NUM> and/or edge <NUM>.

<FIG> shows a second or centered position of inner blade <NUM> relative to outer blade <NUM>. In this configuration, slider <NUM> is centered on either side of ridges <NUM> such that flanges <NUM> extend an equal distance over the ridges <NUM> on either side. Flange <NUM> extends an equal distance over ridges <NUM> on both sides of slider <NUM>. This configuration centers channel <NUM> so that T-guide <NUM> and guide rail <NUM> are centered and arm <NUM> is centered within slider <NUM>. Inner-blade edge <NUM> is in a mid-location, being neither fully extended nor fully retracted. Inner-blade edge <NUM> of inner blade <NUM> is midway between full extraction and full retraction above outer blade edge <NUM> of outer blade <NUM>, forming a medium sized blade gap <NUM>. This configuration results in a medium or "mid-length" cut.

<FIG> shows a fully retracted inner blade <NUM>. Slider <NUM> is fully extended to the right. Slider <NUM> is closer to the second fastener hole <NUM> on the right than it is to the first fastener hole <NUM> on the left, providing a visual indication to an operator of the longer cut. The right ridge <NUM> is almost entirely within the right flange <NUM> and the left ridge <NUM> is almost entirely extended within the left flange <NUM>. In this configuration, inner blade <NUM> is fully retracted along outer blade <NUM>, such that inner blade edge <NUM> is maximally displaced from outer blade edge <NUM>. This configuration pulls or displaces angled edge <NUM> a maximum distance away from outer blade edge <NUM> and maximizes the blade gap <NUM> length. Therefore, the cut hair length of cutters <NUM> is maximized, producing a long or "deep" cutting length.

<FIG> illustrate another embodiment of a cutter <NUM> with a blade assembly <NUM>. Blade assembly <NUM> includes an inner blade <NUM> with upper body <NUM> and outer blade <NUM> with lower body <NUM>. The embodiment of cutter <NUM> is substantially the same or similar to the embodiment of cutters <NUM> illustrated in <FIG>, except for the differences described. In contrast the embodiment of cutters <NUM>, the embodiment of cutters <NUM> includes a U-shaped portion <NUM> that defines a guide channel <NUM> and a guide body <NUM> (<FIG>). Similar components of cutter <NUM> are assigned the same reference number as cutter <NUM> beginning with <NUM>.

<FIG> shows inner blade <NUM>, inner body <NUM>, and a plurality of inner blade teeth <NUM>. Inner blade teeth <NUM> extend along an inner blade edge <NUM>. Inner blade edge <NUM> is defined by an imaginary line connecting the tips of inner blade teeth <NUM>. Lower blade <NUM> includes body <NUM> and a plurality of outer blade teeth <NUM>. Outer blade teeth <NUM> extend along an outer blade edge <NUM>. Outer blade edge <NUM> is defined by an imaginary line connecting the tips of outer blade teeth <NUM>. In some embodiments, inner blade edge <NUM> and outer blade edge <NUM> are defined as a line connecting the roots (rather than the tips) of teeth <NUM> and/or <NUM>. Upper blade <NUM> is positioned on top (or sits on top) of outer blade <NUM>, with inner blade edge <NUM> being parallel to and offset from outer blade edge <NUM> by a blade gap <NUM>. The distance between inner blade edge <NUM> and outer blade edge <NUM> is defined as blade gap <NUM>.

In some embodiments, inner blade <NUM>, outer blade <NUM>, yoke <NUM>, and/or blade guide assembly <NUM> are magnetized to create an attractive or repulsive force between inner blade <NUM> and outer blade <NUM>. For example, a magnetic assembly is located on at least one of a yoke <NUM>, inner blade <NUM>, outer blade <NUM>, or T-guide <NUM>. In other words, inner blade <NUM>, outer blade <NUM>, yoke <NUM>, T-guide <NUM>, and/or any combination thereof, creates a magnetic field to adjust or control a tensile force (attractive or repulsive) between inner and outer blades <NUM> and <NUM>. For example, a magnetized yoke <NUM> is a non-conductive magnet carrier (e.g., a plastic yoke <NUM> carrying a ferrous magnet <NUM>) or conductive magnetic material. In some embodiments, a compounding force is generated from a plurality of magnets <NUM> with relatively weaker magnetic forces to create a compounded magnetic force from the plurality of magnets <NUM>. A variety of magnets may be used and may reduce the total cost of the magnetic assembly. In addition, using a magnetic force to control the force between blades <NUM> and <NUM> creates a reliable and efficient method to control the tensile force generated to maintain the friction between blades <NUM> and <NUM> while cutting hair.

Referring to <FIG>, a blade guide assembly <NUM> includes a blade guide <NUM> and a projection <NUM> that is received by a slot <NUM> within outer blade <NUM>. Blade guide assembly <NUM> maintains a relative position of the inner blade edge <NUM> relative to outer blade edge <NUM>. Slot <NUM> is positioned in body <NUM> and extends parallel to outer blade edge <NUM>. In other embodiments, slot <NUM> is oriented in any suitable direction relative to outer blade edge <NUM>. Blade guide <NUM> is also coupled to outer blade <NUM>. For example, blade guide <NUM> is fastened by a friction fit (e.g., projection <NUM> is frictionally received by slot <NUM>, etc.), an adhesive, and/or any suitable fastener (e.g., a screw, etc.). Receiving projection <NUM> orients blade guide <NUM> relative to outer blade <NUM> and facilitates guidance of inner blade <NUM>.

Referring to <FIG>, U-shaped portion <NUM> defines guide channel <NUM> and guide body <NUM>. Guide channel <NUM> receives an end of inner blade <NUM> that is opposite inner blade edge <NUM> (e.g., a back end or edge of inner blade <NUM>). Guide channel <NUM> is oriented parallel to inner blade edge <NUM> to facilitate reciprocating (or lateral) guidance of inner blade <NUM> relative to outer blade <NUM> during oscillation. Guide body <NUM> extends away from guide channel <NUM>, and is positioned between inner and outer blades <NUM> and <NUM>. Guide body <NUM> has a top side adjacent to inner blade <NUM> and a bottom side adjacent to outer blade <NUM>.

In some embodiments, blade assembly <NUM> includes a magnetic tension assembly <NUM>. Magnetic tension assembly <NUM> uses electromagnetic forces to apply an attractive or tension force between inner blade <NUM> and outer blade <NUM>, for example, blade assembly <NUM> and inner and/or outer blades <NUM> and/or <NUM>. In some embodiments, magnetic tension assembly <NUM> replaces traditional spring based systems that apply a tension force between blades <NUM> and <NUM>. The attractive tensile force maintains inner blade <NUM> position (up and down) relative to outer blade <NUM> during oscillatory reciprocation (e.g., cutting hair).

As will be described in detail below, in some embodiments, the magnetic tensile force between inner and/or outer blades <NUM> and/or <NUM> is adjustable. In some embodiments, the magnetic polarities are reversed, such that the magnetic force repels the inner and outer blades <NUM> and <NUM> (e.g., generates a repulsive force on blades <NUM> and <NUM>).

Magnetic tension assembly <NUM> includes a magnetized ferromagnetic material and/or at least one magnet <NUM> positioned between inner and outer blades <NUM> and <NUM>. The illustrated bar magnet <NUM> is sandwiched between inner and outer blades <NUM> and <NUM>. In other embodiments, magnet <NUM>, includes any suitable electromagnetic force (e.g., a permanent magnet, a polymagnet, electric coil, etc.) or shape (e.g., circular, oblong, or a magnetized cross-member or guide rail <NUM>). In some embodiments, magnet <NUM> includes a plurality of magnets positioned between inner and outer blades <NUM> and <NUM>. Magnet <NUM> is fastened (or otherwise coupled) to outer blade <NUM>. For example, magnet <NUM> is fastened by an adhesive, a fastener (e.g., a screw, etc.), or any other suitable fastening device. Magnet <NUM> then applies an attractive magnetic or tensile force on inner blade <NUM> during oscillation. Stated another way, inner blade <NUM> is drawn towards outer blade <NUM> by magnet <NUM>. The attractive tensile force applied by magnet <NUM> is such that inner blade <NUM> is able to reciprocate relative to outer blade <NUM> while maintaining the position of inner blade edge <NUM> relative to outer blade edge <NUM>. Magnet <NUM> is captured between the blades <NUM> and <NUM> to apply a magnetic attractive (e.g., tensile) force on inner blade <NUM>, which provides improved tension control of inner blade <NUM> during reciprocation.

In operation, motor <NUM> drives reciprocation of inner blade <NUM> relative to outer blade <NUM> through a drive assembly <NUM> and/or a transmission (not shown). During reciprocation of inner blade <NUM>, blade guide assembly <NUM> guides reciprocal movement of inner blade <NUM> relative to outer blade <NUM> to maintain a consistent blade gap <NUM>. In addition, magnetic tension assembly <NUM> applies a magnetic tensile force on inner blade <NUM> to maintain the position of inner blade edge <NUM> relative to outer blade edge <NUM> to reduce friction and facilitate an even cut.

<FIG> illustrate another embodiment of a cutter <NUM> with a blade assembly <NUM>. Blade assembly <NUM> includes an inner blade <NUM> with upper body <NUM> and outer blade <NUM> with lower body <NUM>. The embodiment of cutter <NUM> is substantially the same or similar to the embodiment of cutters <NUM> and <NUM>, except for the differences described. In contrast the embodiment of cutters <NUM> and <NUM>, the embodiment of <NUM> includes an alternative fastener <NUM> for blade guide assembly <NUM> to outer blade <NUM>. In addition, blade assembly <NUM> of cutter <NUM> includes an alternative embodiment of a magnetic tension assembly <NUM>. Similar components of cutter <NUM> are assigned the same reference number of cutters <NUM> and <NUM> beginning with <NUM>.

In some embodiments, inner blade <NUM>, outer blade <NUM>, yoke <NUM>, and/or blade guide assembly <NUM> are magnetized to create an attractive or repulsive force between inner blade <NUM> and outer blade <NUM>. For example, a magnetic assembly is located on at least one of a yoke <NUM>, inner blade <NUM>, outer blade <NUM>, or T-guide <NUM>. In other words, inner blade <NUM>, outer blade <NUM>, yoke <NUM>, blade guide assembly <NUM>, and/or any combination thereof, creates a magnetic field to adjust or control a tensile force (attractive or repulsive) between inner and outer blades <NUM> and <NUM>. For example, a magnetized yoke <NUM> is a non-conductive magnet carrier (e.g., a plastic yoke <NUM> carrying a ferrous magnet <NUM>) or conductive magnetic material. In some embodiments, a compounding force is generated from a plurality of magnets <NUM> with relatively weaker magnetic forces to create a compounded magnetic force from the plurality of magnets <NUM>. A variety of magnets may be used and may reduce the total cost of the magnetic assembly. In addition, using a magnetic force to control the force between blades <NUM> and <NUM> creates a reliable and efficient method to control the tensile force generated to maintain the friction between blades <NUM> and <NUM> while cutting hair.

<FIG> illustrate projection <NUM> of blade guide <NUM> with a geometry that is configured to be received by a complimentary geometry of slot <NUM> in outer blade <NUM> of body <NUM>. Specifically, projection <NUM> defines a trapezoidal cross-sectional shape that is received by a trapezoidal slot <NUM>. This allows projection <NUM> to be captured and slidably received by slot <NUM>, while also fastening (and otherwise retaining) the blade guide assembly <NUM> to outer blade <NUM>. Blade guide assembly <NUM> maintains a relative position of the inner blade edge <NUM> relative to outer blade edge <NUM>. Effectively projection <NUM> and slot <NUM> together form a dovetail joint (or a dovetail) to provide resistance to separation. Projection <NUM> can have any suitable cross-sectional shape (e.g., geometric, triangular, etc.) that is received by a complimentary cross-sectional shape defined by slot <NUM> to fasten blade guide assembly <NUM> to outer blade <NUM>.

<FIG> illustrate blade assembly <NUM> with magnetic tension assembly <NUM>. Magnetic tension assembly <NUM> includes a first, top, or upper magnet holder <NUM> coupled to outer blade <NUM> by a fastener <NUM> (e.g., as shown in <FIG>). Upper magnet holder <NUM> includes a pair of arms or extensions 396a, 396b that retain (or hold) a first, top, or upper magnet 376a. In other words, upper magnet 376a is fastened to extensions 396a and 396b (e.g., by an adhesive, a fastener such as a screw or bolt, etc.). Upper magnet 376a is illustrated as a bar magnet <NUM>. However, in other embodiments, upper magnet 376a is any suitable magnet <NUM> or plurality of magnets <NUM>. Extensions 396a and 396b of upper magnet holder <NUM> extend over inner blade <NUM>. Upper magnet holder <NUM> is positioned on a side of inner blade <NUM> opposite the side that faces outer blade <NUM>.

Referring to <FIG>, a second, bottom, or lower magnet 376b is fastened to inner blade <NUM> (e.g., by an adhesive, a fastener such as a screw or bolt, etc.). Bottom magnet 376b is illustrated as a bar magnet 376b. However, in other embodiments, bottom magnet 376b is any suitable magnet <NUM> or plurality of magnets <NUM>. Bottom magnet 376b is positioned on the side of inner blade <NUM> opposite the side that faces outer blade <NUM>. Thus, upper magnet <NUM> and bottom magnet 376b are in an opposite facing relationship or orientation, opposite each other. In this configuration, upper magnet 376a is stationary (e.g., held by extensions 396a and 396b coupled to outer blade <NUM>), while bottom magnet 376b is coupled to inner blade <NUM> and configured to move or oscillate with inner blade <NUM> during operation. Thus, bottom magnet 376b reciprocates with inner blade <NUM>.

In some embodiments, upper magnet <NUM> and bottom magnet 376b are magnets having the same polarity, such that the inner and outer blades <NUM> and <NUM> experience a repulsive force. In some embodiments, upper magnet <NUM> and bottom magnet 376b have opposite polarity, such that the inner and outer blades <NUM> and <NUM> experience an attractive force. Thus, the orientations of magnets 376a and 376b are such that they magnetically repel each other. Magnets 376a and 376b push apart or repel, with bottom magnet 376b pushing inner blade <NUM> towards outer blade <NUM>. This generates a magnetic force that separates the blades <NUM> and <NUM> to maintain the position of inner blade edge <NUM> relative to outer blade edge <NUM> during operation to reduce frictional load and facilitate cutting. As will be described in detail below, in some embodiments, the magnetic force between inner and/or outer blades <NUM> and/or <NUM> is adjustable.

<FIG> illustrate another embodiment of a cutter <NUM> with a blade assembly <NUM>. Blade assembly <NUM> includes an inner blade <NUM> coupled to an outer blade <NUM>. The embodiment of cutter <NUM> is substantially the same or similar to the embodiments of cutters <NUM>, <NUM>, and <NUM>, except for the differences described. In contrast to the embodiment of cutters <NUM>, <NUM>, and <NUM>, the embodiment of cutters <NUM> includes blade assembly <NUM> with alternative embodiments of magnetic tension assembly <NUM> and blade guide assembly <NUM>. Blade assembly <NUM> is shown as coupled to an embodiment of the cutters <NUM>. Similar components of cutter <NUM> are assigned the same reference number as cutter <NUM> beginning with <NUM>.

In some embodiments, inner blade <NUM>, outer blade <NUM>, yoke <NUM>, and/or Blade guide assembly <NUM> are magnetized to create an attractive or repulsive force between inner blade <NUM> and outer blade <NUM>. For example, a magnetic assembly is located on at least one of a yoke <NUM>, inner blade <NUM>, outer blade <NUM>, or blade guide assembly <NUM>. In other words, inner blade <NUM>, outer blade <NUM>, yoke <NUM>, blade guide assembly <NUM>, and/or any combination thereof, creates a magnetic field to adjust or control a tensile force (attractive or repulsive) between inner and outer blades <NUM> and <NUM>. For example, a magnetized yoke <NUM> is a non-conductive magnet carrier (e.g., a plastic yoke <NUM> carrying a ferrous magnet <NUM>) or conductive magnetic material. In some embodiments, a compounding force is generated from a plurality of magnets <NUM> with relatively weaker magnetic forces to create a compounded magnetic force from the plurality of magnets <NUM>. A variety of magnets may be used and may reduce the total cost of the magnetic assembly. In addition, using a magnetic force to control the force between blades <NUM> and <NUM> creates a reliable and efficient method to control the tensile force generated to maintain the friction between blades <NUM> and <NUM> while cutting hair.

<FIG> illustrate blade guide assembly <NUM> with a guide member <NUM> that defines a guide surface <NUM>. Blade guide assembly <NUM> maintains a relative position of the inner blade edge <NUM> relative to outer blade edge <NUM>. Guide surface <NUM> is a sloped surface that is configured to engage a portion of inner blade <NUM>. More specifically, guide surface <NUM> engages an end of inner blade <NUM> opposite inner blade edge <NUM> (e.g., the back end of inner blade <NUM>). Upper blade <NUM> is configured to slide along guide surface <NUM> during reciprocation to guide the reciprocal movement of inner blade <NUM> relative to outer blade <NUM> and maintain a consistent gap <NUM>. In some embodiments, guide assembly <NUM> is a guide rail <NUM> of a T-guide <NUM>, the same as or similar to T-guide <NUM> and/or guide rail <NUM>. In this configuration, guide rail <NUM> of T-guide <NUM> is captured between inner and outer blades and has a top side adjacent to inner blade <NUM> and a bottom side adjacent to outer blade <NUM>.

<FIG> illustrates blade guide assembly <NUM> with a blade gap adjustable lever <NUM>. In some embodiments adjustable lever <NUM> is similar to slider <NUM> and operates to change a gap <NUM> length. For example, rotation of adjustment lever <NUM> slides or translates a guide member <NUM> forward or backwards in a transverse direction relative to the oscillatory motion of inner blade <NUM>. As guide member <NUM> moves forward, inner blade <NUM> also moves forward and decreases blade gap <NUM>. As guide member <NUM> moves backwards, inner blade <NUM> also moves backward and increases blade gap <NUM>.

<FIG> illustrate magnetic tension assembly <NUM> of cutters <NUM>. Magnetic tension assembly <NUM> includes a magnet <NUM>, illustrated as disc magnets <NUM>. Magnets <NUM> can be any suitable magnet <NUM> or plurality of magnets <NUM>. Magnets <NUM> are positioned on the side of inner blade <NUM> that is opposite the side that faces outer blade <NUM>. Magnets <NUM> provide a magnetic tensile force that attracts inner blade <NUM> towards outer blade <NUM>. The magnetic tensile force is sufficient to draw inner blade <NUM> towards outer blade <NUM>. This generates magnetic tension that maintains the position of inner blade edge <NUM> relative to outer blade edge <NUM> during operation to facilitate cutting.

In some embodiments, the magnetic tensile force between inner and/or outer blades <NUM> and/or <NUM> is adjustable. In some embodiments, the magnetic polarities are reversed, such that the magnetic force repels the inner and/or outer blades <NUM> and/or <NUM>.

<FIG> illustrate another embodiment of a cutter <NUM> with a blade assembly <NUM>. Blade assembly <NUM> includes an inner blade <NUM> and an outer blade <NUM>. The embodiment of cutter <NUM> is substantially the same or similar to the embodiments of <FIG>, except for the differences described. In contrast to the embodiments of <FIG>, blade assembly <NUM> includes an alternative embodiment of a magnetic tension assembly <NUM> and blade guide assembly <NUM>. Blade guide assembly <NUM> maintains a relative position of the inner blade edge <NUM> relative to outer blade edge <NUM>. Blade assembly <NUM> is shown as coupled to an embodiment of the cutters <NUM>. Similar components of cutter <NUM> are assigned the same reference number as cutters <NUM> beginning with <NUM>.

In some embodiments, guide assembly <NUM> includes a guide rail <NUM> of a T-guide <NUM>, the same as or similar to T-guide <NUM> and/or guide rail <NUM>. In this configuration, guide rail <NUM> of T-guide <NUM> is captured between inner and outer blades <NUM> and <NUM> and has a top side adjacent to inner blade <NUM> and a bottom side adjacent to outer blade <NUM>.

Magnetic tension assembly <NUM> is substantially the same as the magnetic tension assembly <NUM>, with like numbers identifying like components. Magnetic tension assembly <NUM> includes a metallic member <NUM> coupled to outer blade <NUM> (e.g., an adhesive and/or fastener). Metallic member <NUM> is positioned on outer blade <NUM> and sandwiched between inner and outer blades <NUM> and <NUM>. Stated another way, metallic member <NUM> is positioned on an internal side of outer blade <NUM> that faces inner blade <NUM>, and between inner and outer blades <NUM> and blade <NUM>. Metallic member <NUM> provides an additional surface or material that attract magnets <NUM>. Thus, metallic member <NUM> engages with the attractive magnetic force emitted from magnets <NUM> that attracts inner blade <NUM> towards outer blade <NUM>, drawing inner blade <NUM> towards outer blade <NUM>. The generated magnetic tension maintains the position of inner blade edge <NUM> relative to outer blade edge <NUM> during operation. In this embodiment blades <NUM> and/or <NUM> need not be a metallic component, for example, blade <NUM> or <NUM> is a plastic or composite part.

Metallic member <NUM> can be any suitable ferromagnetic material or other suitable material that attracts to magnets <NUM> by magnetic force. In some embodiments, metallic member <NUM> is magnetized with the same polarity as magnets <NUM>, such that inner and outer blades <NUM> and <NUM> are repelled. As will be described in detail below, in some embodiments, the magnetic force between inner and/or outer blades <NUM> and/or <NUM> is adjustable or scalable.

<FIG> illustrate another embodiment of cutters <NUM> with blade assembly <NUM>. Blade assembly <NUM> includes an inner blade <NUM> and an outer blade <NUM>. The embodiment of cutter <NUM> is substantially the same or similar to the embodiments of <FIG>, except for the differences described. In contrast to the embodiments of <FIG>, cutters <NUM> include an alternative blade guide assembly <NUM> with an alternative embodiment of a magnetic tension assembly <NUM>. Similar components of cutter <NUM> are assigned the same reference number as cutters <NUM> beginning with <NUM>. As will be described in detail below, in some embodiments, the magnetic tensile force between inner and/or outer blades <NUM> and/or <NUM> is adjustable.

In some embodiments, inner blade <NUM>, outer blade <NUM>, yoke <NUM>, and/or T-guide <NUM> are magnetized to create an attractive or repulsive force between inner blade <NUM> and outer blade <NUM>. For example, a magnetic assembly is located on at least one of a yoke <NUM>, inner blade <NUM>, outer blade <NUM>, or T-guide <NUM>. In other words, inner blade <NUM>, outer blade <NUM>, yoke <NUM>, T-guide <NUM>, and/or any combination thereof, creates a magnetic field to adjust or control a tensile force (attractive or repulsive) between inner and outer blades <NUM> and <NUM>. For example, a magnetized yoke <NUM> is a non-conductive magnet carrier (e.g., a plastic yoke <NUM> carrying a ferrous magnet <NUM>) or conductive magnetic material. In some embodiments, a compounding force is generated from a plurality of magnets <NUM> with relatively weaker magnetic forces to create a compounded magnetic force from the plurality of magnets <NUM>. A variety of magnets may be used and may reduce the total cost of the magnetic assembly. In addition, using a magnetic force to control the force between blades <NUM> and <NUM> creates a reliable and efficient method to control the tensile force generated to maintain the friction between blades <NUM> and <NUM> while cutting hair.

<FIG> show blade guide assembly <NUM> with guide member <NUM>. Blade guide assembly <NUM> maintains a relative position of the inner blade edge <NUM> relative to outer blade edge <NUM>. In some embodiments, guide member <NUM> is the same or similar to T-guide <NUM>. Guide member <NUM> is T-shaped and mounted to outer blade <NUM> by an adjustment assembly <NUM> (shown in <FIG>). In this configuration, cross-member <NUM> of T-guide <NUM> is captured between inner and outer blades <NUM> and <NUM> and has a top side adjacent to inner blade <NUM> and a bottom side adjacent to outer blade <NUM>. In some embodiments, adjustment assembly <NUM> includes slider <NUM>, lever <NUM>, and/or lever <NUM>. Adjustment assembly <NUM> operates to translate inner blade <NUM> over outer blade <NUM> to increase or decrease gap <NUM>. T-shaped guide member <NUM> includes a guide base <NUM> (the same or similar to extension arm <NUM>) and a cross member, portion, or guide rail <NUM> (the same or similar to guide rail <NUM>). An outline of guide rail <NUM> is shown in broken lines in <FIG>.

Guide rail <NUM> is positioned between inner and outer blades <NUM> and <NUM> (<FIG>). Adjustment assembly <NUM> includes a lever <NUM> (<FIG>) that facilitates movement of inner blade <NUM> relative to outer blade <NUM> and adjusts blade gap <NUM>. Specifically, movement of lever <NUM> in a first direction generates along a base opposite lower blade edge <NUM> of outer blade <NUM> provides a translational force on guide base <NUM> in a direction transverse to the oscillatory direction. The translational force moves guide member <NUM> in a translational direction (e.g., forward). Guide member <NUM> translates inner blade <NUM> in same translational direction (e.g., forward) to increase/decrease blade gap <NUM>. For example, movement of lever <NUM> in an opposite direction (e.g., backward) generates a translational force on guide base <NUM> that translates guide member <NUM> back to its original position. Guide member <NUM> couples to inner blade <NUM> to translate blade <NUM> in the same direction and increase or decrease blade gap <NUM>.

<FIG> illustrate magnetic tension assembly <NUM>. Magnetic tension assembly <NUM> includes a magnet <NUM>, illustrated as a plurality of disc magnets <NUM>. Magnets <NUM> can be any suitable magnet <NUM> or plurality of magnets <NUM>. Magnets <NUM> are positioned or coupled to guide member <NUM>. In some embodiments Guide member <NUM> is the same or similar as T-guide <NUM>. Magnets <NUM> are fastened to guide rail <NUM> of guide rail <NUM> and/or cross member <NUM>. For example, magnets <NUM> are disc magnets <NUM> configured to be received in an associated aperture defined in the cross member <NUM> or guide rail <NUM>. Magnets <NUM> are slidably received by the associated apertures and have a geometry that facilitates retention (e.g., a "top hat" geometry, etc.). In other embodiments, magnets <NUM> are coupled to guide rail <NUM> or cross member <NUM> (e.g., by an adhesive, fastener, etc.). Magnets <NUM> are positioned to face an underside of inner blade <NUM> or an internal side of inner blade <NUM> that faces guide member <NUM>. Magnets <NUM> provide an attractive magnetic force that engages inner blade <NUM> and draws inner blade <NUM> towards guide member <NUM> (and thus towards outer blade <NUM>). The magnetic force is sufficient to generate an attractive magnetic tension between blades <NUM> and <NUM> that maintains the position of inner blade edge <NUM> relative to outer blade edge <NUM> during operation to reduce load on motor <NUM> and facilitate cutting.

<FIG> illustrate another embodiment of cutter <NUM> with blade assembly <NUM>. Blade assembly <NUM> includes an inner blade <NUM> and an outer blade <NUM>. A blade guide assembly <NUM> maintains a relative position of the inner blade edge <NUM> relative to outer blade edge <NUM>. In some embodiments, guide assembly <NUM> includes a guide rail <NUM> of a T-guide <NUM>, the same as or similar to T-guide <NUM> and/or guide rail <NUM>. In this configuration, guide rail <NUM> of T-guide <NUM> is captured between inner and outer blades <NUM> and <NUM> and has a top side adjacent to inner blade <NUM> and a bottom side adjacent to outer blade <NUM>.

The embodiment of cutter <NUM> is substantially the same or similar to the embodiments of <FIG>, except for the differences described. In contrast to the embodiments of <FIG>, cutter <NUM> includes alternative embodiment of a magnetic tension assembly <NUM> that includes an electromagnet <NUM>.

In some embodiments, inner blade <NUM>, outer blade <NUM>, yoke <NUM>, T-guide <NUM>, and/or blade guide assembly <NUM> are magnetized to create an attractive or repulsive force between inner blade <NUM> and outer blade <NUM>. For example, a magnetic assembly is located on at least one of a yoke <NUM>, inner blade <NUM>, outer blade <NUM>, T-guide <NUM>, or blade guide assembly <NUM>. In other words, inner blade <NUM>, outer blade <NUM>, yoke <NUM>, T-guide <NUM>, blade guide assembly <NUM>, and/or any combination thereof, creates a magnetic field to adjust or control a tensile force (attractive or repulsive) between inner and outer blades <NUM> and <NUM>. For example, a magnetized yoke <NUM> is a non-conductive magnet carrier (e.g., a plastic yoke <NUM> carrying a ferrous magnet <NUM>) or conductive magnetic material. In some embodiments, a compounding force is generated from a plurality of magnets <NUM> with relatively weaker magnetic forces to create a compounded magnetic force from the plurality of magnets <NUM>. A variety of magnets may be used and may reduce the total cost of the magnetic assembly. In addition, using a magnetic force to control the force between blades <NUM> and <NUM> creates a reliable and efficient method to control the tensile force generated to maintain the friction between blades <NUM> and <NUM> while cutting hair.

With reference to <FIG>, electromagnet <NUM> includes a member <NUM> with windings <NUM>. Electromagnet <NUM> is coupled to inner blade <NUM>. More specifically, member <NUM> includes a first end <NUM> and a second end <NUM> (shown in <FIG>). The first and second ends <NUM> and <NUM> extend through inner blade <NUM> and contact outer blade <NUM>. In operation, electricity (or an electrical charge or current) is applied to windings <NUM> to magnetize member <NUM>. The magnetic field extends through the first and second ends <NUM> and <NUM> to engage outer blade <NUM>. The ends <NUM> and <NUM> concentrate a magnetic flux that provides an attractive magnetic force (e.g., tension or tensile force) that engages outer blade <NUM> and draws inner blade <NUM> towards outer blade <NUM>. The magnetic force is sufficient to generate magnetic tension that maintains the position of inner blade edge <NUM> relative to outer blade edge <NUM> during operation. Thus, the ends <NUM> and <NUM> act as a magnetic conduit (or electromagnet) to draw inner blade <NUM> towards outer blade <NUM>.

The current or voltage (or electric charge) supplied to electromagnet <NUM> from magnetic tension assembly <NUM> can be associated with operation of cutters <NUM>. Specifically, a load sensor <NUM> is incorporated with cutters <NUM> to detect increases and/or decreases in a load on or speed of motor <NUM>. Changes in the load or speed of motor <NUM> are proportional to a frictional load or speed between blades <NUM> and <NUM>. Sensor <NUM> sends signals indicative of load and/or speed changes on motor <NUM> to electromagnet <NUM> to increase or decrease the magnetic force between inner and outer blades <NUM> and <NUM>. Changes in load on motor <NUM> are representative and/or proportional to the frictional load (and/or speed) between blades <NUM> and <NUM> incurred during the cutting of hair. As the detected load increases or the speed decreases, the voltage and/or current supplied to electromagnet <NUM> is increased to improve tension between inner blade <NUM> and outer blade <NUM>. For example, when sensor <NUM> detects a changed load on motor <NUM> or change of speed between motor <NUM>, inner blade <NUM> and/or outer blade <NUM>, sensor <NUM> sends a signal to electromagnet <NUM> to increase current in magnetic tension assembly <NUM> that increases the magnetic attractive or tensile force between guide member <NUM> and inner and outer blades <NUM> and <NUM> and reduces the frictional load and reduces the load on motor <NUM>.

<FIG> illustrate another embodiment of cutters <NUM> with blade assembly <NUM>. Blade assembly <NUM> includes an inner blade <NUM> and an outer blade <NUM>. A blade guide assembly <NUM> maintains a relative position of the inner blade edge <NUM> relative to outer blade edge <NUM>. In some embodiments, guide assembly <NUM> includes a guide rail <NUM> of a T-guide <NUM>, the same as or similar to T-guide <NUM> and/or guide rail <NUM>. In this configuration, guide rail <NUM> of T-guide <NUM> is captured between inner and outer blades <NUM> and <NUM> and has a top side adjacent to inner blade <NUM> and a bottom side adjacent to outer blade <NUM>.

The embodiment of cutter <NUM> is substantially the same or similar to the embodiments of <FIG>, except for the differences described. In contrast the embodiments of <FIG>, cutter <NUM> includes an alternative embodiment of magnetic tension assembly <NUM>. Magnetic tension assembly <NUM> includes electromagnet <NUM> that is coupled to outer blade <NUM>. Magnetic tension assembly <NUM> is substantially the same or similar as magnetic tension assembly <NUM> and electromagnet <NUM> (<FIG>), except for the differences described. In contrast to magnetic tension assembly <NUM>, magnetic tension assembly <NUM> couples to outer blade (<FIG>) whereas magnetic tension assembly <NUM> couples to inner blade <NUM> (<FIG>).

The first and second ends <NUM> and <NUM> of magnetic tension assembly <NUM> extend through outer blade <NUM> and contact inner blade <NUM>. In operation, electricity (or an electrical charge or current) is applied to windings <NUM> to magnetize member <NUM>. The magnetic field extends through the first end <NUM> and the second end <NUM> to engage inner blade <NUM>. The ends <NUM> and <NUM> concentrate the magnetic flux to provide an attractive magnetic force (e.g., tension force) that engages and draws inner blade <NUM> towards outer blade <NUM>. The magnetic force is sufficient to generate magnetic tension to maintain the position of inner blade edge <NUM> relative to outer blade edge <NUM> during operation to facilitate cutting. Thus, the ends <NUM> and <NUM> act as a magnetic conduit (or electromagnet) that draws inner blade <NUM> towards outer blade <NUM>.

The current or voltage (or electricity or electric charge) supplied to electromagnet <NUM> from magnetic tension assembly <NUM> can be associated with operation of cutters <NUM>. Specifically, a load or speed sensor <NUM> is incorporated with cutters <NUM> to detect increases and/or decreases in a load on or speed of motor <NUM>. Changes in the load or speed of motor <NUM> are proportional to a frictional load between blades <NUM> and/or <NUM>. Sensor <NUM> sends signals indicative of the load and or speed changes on motor <NUM> to electromagnet <NUM> to increase or decrease the magnetic force between inner and outer blades <NUM> and <NUM>. Changes in load on motor <NUM> are representative and/or proportional to the frictional load between blades <NUM> and <NUM> incurred during the cutting of hair. Similarly, changes in speed of motor <NUM>, inner and/or outer blades <NUM> and/or <NUM> are representative and/or proportional to the frictional load between blades <NUM> and <NUM>. As the detected load increases or speed decreases, the voltage and/or current supplied to electromagnet <NUM> is increased to improve tension between inner blade <NUM> and outer blade <NUM>. For example, when sensor <NUM> detects a changed load or speed on motor <NUM>, sensor <NUM> sends a signal to electromagnet <NUM> to increase current in magnetic tension assembly <NUM> that increases the magnetic attractive or tensile force between guide member <NUM> and inner and/or outer blades <NUM> and/or <NUM> and reduces the frictional and motor <NUM> loads.

In some embodiments, electromagnet <NUM> is used in association with other magnets <NUM> (e.g., <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>), such as those disclosed in association with the other embodiments of magnetic tension assembly (e.g., <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>). Further, electromagnet <NUM> (and/or magnets <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>) can be associated with at least one sensor <NUM> to facilitate selective engagement (or magnetization) of electromagnet <NUM>. For example, electromagnet <NUM> is associated with a proximity sensor <NUM> configured to detect hair, a motion sensor <NUM> configured to detect movement of cutters <NUM>, and/or a sound sensor <NUM> configured to detect the sound of clipper operation (or motor <NUM> operation). In response to an associated detection by sensor <NUM>, electromagnet <NUM> selectively engages electromagnet <NUM> (e.g., sends signals to increase or decrease a current to electromagnet <NUM>). Thus, a magnetic force between inner blade <NUM> and outer blade <NUM> is selectively variable. Selective application of the magnetic force reduces the friction load between blades <NUM> and <NUM>, the motor <NUM> load, and heat emitted by cutters <NUM>, allowing the user an improved experience during use. In other words, sensor <NUM> communicates with electromagnet <NUM> to enhance overall performance and lifecycle of cutter <NUM>.

Claim 1:
A magnetic blade assembly (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>), comprising:
a first blade (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>) comprising a first blade edge (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>) having a plurality of teeth (<NUM>; <NUM>);
a second blade (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>) comprising a second blade edge (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>) having a plurality of teeth (<NUM>; <NUM>), the second blade edge being parallel to the first blade edge; wherein the blades oscillate relative to the other; and
a blade guide assembly (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) captured between the first and second blades, the blade guide assembly maintaining a relative position of the first blade edge relative to the second blade edge, the blade guide comprising:
a guide member (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>) including a base (<NUM>) and a cross-portion (<NUM>; <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>), the cross-portion being captured between the first and second blades, the cross-portion having a first side adjacent to the first blade and a second side adjacent to the second blade; and
a magnetic assembly comprising a plurality of magnets (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>; <NUM>) extending along the cross-portion of the guide member between the first and second blades; wherein the magnetic assembly generates an attractive force between the blade guide assembly and the first blade;
characterised in that the cross-portion of the guide member is a ferromagnetic material that is magnetized.