Cutting length adjustment mechanism, adjustment drive and hair cutting appliance

Abstract

A cutting length adjustment mechanism for a hair cutting appliance, a hair cutting appliance, a method of operating a cutting length adjustment mechanism for a hair cutting appliance and an adjustment drive for a cutting length adjustment mechanism for a hair cutting appliance wherein the adjustment drive includes an actuator that is configured to actuate a movable portion of the cutting length adjustment mechanism with respect to a housing portion of the hair cutting appliance, and a movement sensor unit that is configured to detect a movement of the hair cutting appliance, the movement involving at least one of an orientation change and a position change. The actuator is further configured to output an adjustment control signal that is derived from the detected movement. In a length adjustment mode, the actuator is operated on the basis of the adjustment control signal.

Claims

1. An adjustment drive for a cutting length adjustment mechanism for a hair cutting appliance, the adjustment drive comprising: an actuator configured to have both of a standard mode or a cutting length adjustment node, wherein in the cutting length adjustment mode, the actuator is configured to actuate a movable portion of the cutting length adjustment mechanism with respect to a housing portion of the hair cutting appliance, and a movement sensor unit configured to: detect a movement of the hair cutting appliance, said movement of the hair cutting appliance comprising at least one of: an orientation change and a position change, determine an adjustment control signal based on a rate of change and direction of said detected movement of said hair cutting appliance; and output said adjustment control signal derived from the detected movement, wherein in the standard mode involving a cutting action, the actuator is deactivated, wherein, in the cutting length adjustment mode, the actuator is operated on the basis of the adjustment control signal, and wherein when the movement sensor detects at least one of: a forward rotation of the hair cutting appliance: a rearward rotation of the hair cutting appliance; a speed of rotation of the hair cutting appliance; and a rotation angle of the hair cutting appliance, and the actuator is operating in the cutting length adjustment mode, the adjustment control signal causes a length adjustment of the cutting length adjustment mechanism.

2. The adjustment drive as claimed in claim 1, wherein the movement sensor unit comprises: at least one movement sensor comprising at least one of: an accelerometer sensor and a gyroscope sensor.

3. The adjustment drive as claimed in claim 1, wherein the movement sensor unit is configured to: detect one of: an absolute orientation change and an absolute position change of the hair cutting appliance with respect to an overall reference frame, wherein said reference frame is based on a gravity system.

4. The adjustment drive as claimed in claim 1, wherein the movement sensor unit is configured to: detect one of: a relative orientation change and position change of the hair cutting appliance with respect to a previous orientation or position of said hair cutting appliance.

5. The adjustment drive as claimed in claim 1, wherein the movement sensor unit is configured to: detect at least one of a pitch movement, a roll movement and yaw movement of the hair cutting appliance, wherein a roll axis is aligned with a main elongation direction of the hair cutting appliance, wherein a pitch axis is perpendicular to the roll axis and basically parallel to a leading edge of the blade set hair cutting appliance, and wherein a yaw axis is perpendicular to the roll axis and perpendicular to the pitch axis.

6. The adjustment drive as claimed in claim 1, wherein when the movement sensor detects the forward rotation of the hair cutting appliance and the actuator is operating in the cutting length adjustment mode, the adjustment control signal causes a length enlargement of the cutting length adjustment mechanism, and wherein when the movement sensor detects the rearward rotation hair cutting appliance of the hair cutting appliance and the actuator is operating in the cutting length adjustment mode, the adjustment control signal causes a length reduction of the cutting length adjustment mechanism.

7. The adjustment drive as claimed in claim 1, wherein when the movement sensor detects the speed of rotation of the hair cutting appliance and the actuator is operating in the cutting length adjustment mode, said adjustment control signal causing one of: an adjustment speed and a length adjustment increment based on said detected speed of rotation of the hair cutting appliance.

8. The adjustment drive as claimed in claim 1, wherein when the movement sensor detects the rotation angle of the hair cutting appliance and the actuator is operating in the cutting length adjustment mode, said adjustment control signal causing one of: an adjustment speed and a length adjustment increment based on said detected rotation angle of the hair cutting appliance.

9. The adjustment drive as claimed in claim 1, wherein length adjustment settings are assigned to rotation orientation states of the hair cutting appliance.

10. The adjustment drive as claimed in claim 1, further comprising: a control unit configured to control operation of the adjustment drive by converting the adjustment control signal into an actuator operating signal.

11. A cutting length adjustment mechanism for a hair cutting appliance, comprising: a movable portion movable with respect to a housing portion of the hair cutting appliance; and an adjustment drive comprising: an actuator configured to have both of a standard mode or a cutting length adjustment mode, wherein in the cutting length adjustment mode, the actuator is configured to actuate said movable portion of the cutting length adjustment mechanism with respect to said housing portion of the hair cutting appliance, a movement sensor unit configured to: detect a movement of the hair cutting appliance, said movement of the hair cutting appliance comprising at least one of: an orientation change and a position change: determine an adjustment control signal based on a rate of change and direction of said detected movement of said hair cutting appliance; and output said adjustment control signal derived from the detected movement, wherein in the standard mode involving a cutting action, the actuator is deactivated; wherein, in the cutting length adjustment mode, the actuator is operated on the basis of the adjustment control signal, and wherein when the movement sensor detects at least one of: a forward rotation of the hair cutting appliance; a rearward rotation of the hair cutting appliance; a speed of rotation of the hair cutting appliance; and a rotation angle of the hair cutting appliance, and the actuator is operating in the cutting length adjustment mode, the adjustment control signal causes a length adjustment of the cutting length adjustment mechanism.

12. A hair cutting appliance comprising: a housing portion, a cutting unit including a blade set, and a cutting length adjustment mechanism as claimed in claim 11.

13. The hair cutting appliance as claimed in claim 12, further comprising: a mode control element configured to set the adjustment drive into the cutting length adjustment mode or the standard mode.

14. The hair cutting appliance as claimed in claim 12, wherein the movement sensor unit is configured to: detect a free rotation of the hair cutting appliance about a central portion of the housing portion.

15. A method of operating a cutting length adjustment mechanism for a hair cutting appliance, the method comprising acts of: providing an adjustment drive comprising an actuator for actuating a movable portion of the cutting length adjustment mechanism, providing a movement sensor configured to detect a movement of the hair cutting appliance, involving at least one of an orientation change and a position change, providing both of a standard mode, wherein a movement of the hair cutting appliance occurs while cutting hair without producing a corresponding change in a cutting length of the hair cutting appliance, or a cutting length adjustment mode, wherein the movement of the hair cutting appliance is provided for producing the corresponding change in the cutting length, wherein during the cutting length adjustment mode, the method comprising acts of: detecting a movement of the hair cutting appliance; determining an adjustment control signal based on at least one of a rate of change and a direction of said detected movement of said hair cutting appliance; operating the actuator to change the cutting length of the hair cutting appliance based on the adjustment control signal, wherein when the movement of the hair cutting appliance is at least one of a forward rotation of the hair cutting appliance; a rearward rotation of the hair cutting appliance; a speed of rotation of the hair cutting appliance; and a rotation angle of the hair cutting appliance, and the actuator is operating in the length adjustment mode, the adjustment control signal causing a length adjustment of the cutting length adjustment mechanism.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and other aspects of the disclosure will be apparent from and elucidated with reference to the embodiments described hereinafter. In the following drawings

(2) FIG. 1 shows a schematic perspective view of an exemplary embodiment of an electric hair cutting appliance and an adjustable spacing comb, wherein the spacing comb is shown in a detached state;

(3) FIG. 2 shows a partial exploded view of an exemplary embodiment of a hair cutting appliance and an adjustable spacing comb, wherein the spacing comb is shown in an insertion orientation;

(4) FIG. 3 shows a simplified top view of an exemplary embodiment of a hair cutting appliance fitted with an adjustable spacing comb and an adjustment drive for the spacing comb;

(5) FIG. 4 shows a schematic simplified side view of an exemplary embodiment of a hair cutting appliance fitted with a retractable spacing comb and an adjustment drive for adjusting the spacing comb;

(6) FIG. 5 is a schematic perspective view of an exemplary hair cutting appliance fitted with an adjustable spacing comb, the hair cutting appliance being held by a user that may operate an adjustment drive for the spacing comb, and wherein an extended state of the adjustable spacing comb is illustrated by dashed lines;

(7) FIG. 6 shows a schematic perspective view of an exemplary embodiment of an electric hair cutting appliance arranged as a hair clipper;

(8) FIG. 7 shows a simplified schematic side view of an exemplary embodiment of a cutting length adjustment mechanism for a hair cutting appliance as shown in FIGS. 6; and

(9) FIG. 8 shows an illustrative block diagram representing several steps of an embodiment of an exemplary method of operating a cutting length adjustment mechanism for a hair cutting appliance in accordance with several aspects of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(10) With reference to FIGS. 1 to 5, certain embodiments that relate to adjustable spacing combs will be elucidated and further detailed. As the present disclosure generally relates to cutting length adjustment mechanisms, further embodiments may be envisaged that comprise length adjustment features for the blade set itself, e.g. a so-called tip-to-tip adjustment. In this context, reference is made to FIGS. 6 and 7 discussed further below. FIG. 1 shows a schematic perspective view of a hair cutting appliance 10, particularly an electrically-operated hair cutting appliance 10. The hair cutting appliance 10 may also be referred to as hair clipper or hair trimmer. The hair cutting appliance 10 may comprise a housing or housing portion 12 having a generally elongated shape. At a first end thereof, a cutting unit 14 may be provided. The cutting unit 14 may comprise a blade set 16. The blade set 16 may comprise a movable blade and a stationary blade that may be moved with respect to each other to cut hair. At a second end of the housing portion 12, a handle or grip portion 18 may be provided. A user may grasp or grab the housing at the grip portion 18.

(11) The hair cutting appliance 10 may further comprise operator controls. For instance, an on-off switch or button 20 may be provided. Furthermore, a length adjustment control 22 may be provided at the housing 12 of the hair cutting appliance 10. The length adjustment control 22 may be provided in case an adjustable spacing comb 26 is attached to the housing portion 12 of the hair cutting appliance 10. In FIG. 1, the adjustable spacing comb 26 is shown in a detached or released state. When the spacing comb 26 is detached from the hair cutting appliance 10, a minimum cutting length may be achieved. When the spacing comb 26 is attached to the hair cutting appliance 10, hairs can be cut to a desired length.

(12) In certain embodiments as disclosed herein, a cutting length adjustment mechanism 24 is provided that may be arranged as an adjustable spacing comb 26, in accordance with the embodiments illustrated in FIGS. 1 to 5.

(13) FIG. 2 shows a partial perspective schematic illustration of a first end of a housing portion 12 of a hair cutting appliance 10. Furthermore, an adjustable spacing comb 26 is shown in an insertion orientation with respect to the housing portion 12. The housing portion 12 and the adjustable spacing comb 26 are shown in an exploded state. By way of example, the spacing comb 26 may comprise an attachment portion 28 which may comprise, for instance, sliding beams 34-1, 34-2. The attachment portion 28 may engage the housing portion 12. More particularly, the attachment portion 28 may be attached to a mounting portion 30 of the housing portion 12. To this end, the sliding beams 34-1, 34-2 may be inserted into respective mounting slots 38-1, 38-2 at the mounting portion 30. The attachment portion 28 may further comprise at least one snap-on member 36 which may be provided at at least one of the sliding beams 34-1, 34-2, for instance. The snap-on member 36 may secure the spacing comb 26 in its mounted state.

(14) As can be further seen from FIG. 2, the spacing comb 26 may further comprise a toothed portion 32 including a plurality of comb teeth. Generally, the toothed portion 32 may comprise a slot in which the blade set 16 can be arranged in the attached state.

(15) With further reference to FIG. 3 and FIG. 4, an exemplary embodiment of an adjustable spacing comb 26 and an embodiment of an exemplary adjustment drive 50 for operating the spacing comb 26 are further illustrated and described. FIG. 3 shows a schematic elevated view of a hair cutting appliance 10. FIG. 4 shows a schematic side view of a hair cutting appliance 10. It is worth mentioning in this regard that the views shown in FIG. 3 and FIG. 4 do not necessarily represent the same arrangement or embodiment. Respective housing portions 12 of the hair cutting appliance 10 are indicated in FIG. 3 and FIG. 4 by dashed lines. Consequently, internal components of the hair cutting appliances 10 are visible.

(16) With particular reference to FIG. 3, the adjustable spacing comb 26 is further described. The adjustable spacing comb 26, refer also to FIG. 1 and FIG. 2, may comprise sliding beams 34 that may cooperate with a carriage 42 that is arranged at the housing 12. Generally, a snap-on mounting of the sliding beams 34 at the carriage 42 may be provided. At least a substantial portion of the spacing comb 26 may be regarded as movable comb portion 40. As can be best seen in FIG. 3, the movable comb portion 40 may be coupled to the carriage 42 and, consequently, moved along with the carriage 42. For driving the carriage 42 and the movable comb portion 40, an engagement member 44 may be provided that is coupled to the carriage 42. For operating or driving the movable comb portion 40 with respect to the blade set 16 (refer to FIG. 1), an adjustment drive 50 may be provided which may also be referred to as adjustment powertrain. In other words, the adjustment drive 50 may be regarded as a motorized adjustment drive 50.

(17) The adjustment drive 50 may comprise an actuator 52 or, more particularly, an electromotor. The actuator 52 may be coupled to a reduction gear 54. The reduction gear 54 may be coupled to a transmission element 56. Generally, the transmission element 56 may be arranged to convert a rotational output motion of the actuator 52 and the reduction gear 54, if any, into a basically longitudinal positioning motion of the movable comb portion 40. A respective longitudinal direction is indicated in FIG. 3 and FIG. 4 by a double arrow denoted by reference numeral 58.

(18) As can be seen from FIGS. 3 and 4, the transmission element 56 may be arranged as threaded spindle, particularly a small pitch spindle. Consequently, the transmission element 56 may be arranged to be set into rotational movements, refer to the curved arrow denoted by reference numeral 60 in FIG. 3. The transmission element 56 may be configured to engage the engagement member 44 so as to push or pull the carriage 42 and, consequently, the movable comb portion 40. In some embodiments, the transmission element 56 may be arranged as gear rack element. In some embodiments, the transmission element 56 may be arranged as push rod element. Generally, the actuator 52 may be mechanically connected to the carriage 42 and, in the mounted state, to the movable comb portion 40.

(19) For operating the adjustment drive 50, respective control elements may be provided. To this end, the adjustment drive 50 may comprise a control unit 64 that is operable to control the actuator 52. The control unit 64 may be supplied with control signals indicating a desired adjustment procedure and a resulting state of the movable comb portion 40.

(20) In accordance with the present disclosure, the adjustment procedure may be controlled by the user by simply moving the appliance 10. Movements and/or orientation changes of the housing 12 of the appliance 10 may be detected by a sensor unit 66 that involves at least one movement sensor 68. The at least one movement sensor 68 may be arranged as a gravity sensor and/or an acceleration sensor. Further, the sensor unit 66 may comprise a set of movement sensors 68. The movement sensor 68 may be arranged as a multi-axes sensor that is operable to detect movements along or about more than one axis. For instance, movements of the appliance 10 may involve translational movements along at least one axis of a set of three axes. Similarly, movements of the appliance 10 may involve rotational movements about at least one axis of a set of three axes.

(21) This sensor unit 66 is arranged to convert respective absolute and/or relative overall movements of the appliance 10 into a control signal for the control unit 64.

(22) Hence, an overall movement (indicated in FIG. 4 by a curved double-arrow 70) may be used to control the adjustment procedure, refer to the double-arrow 58 that indicates a displacement of the movable comb portion 40, refer to the dashed representation of the movable comb portion 40 in an extracted state in FIG. 4.

(23) In at least some embodiments, a mode control element 74 is provided which is operable to set the appliance 10 into a length adjustment mode. In other words, the mode control element may activate and deactivate the length adjustment mode. Preferably, in certain embodiments, only in the length adjustment mode, a respective overall movement 70 of the appliance 12 would cause an adjustment operation of the adjustment drive 50. When the length adjustment mode is deactivated, any movement of the appliance 10 will not induce a length adjustment operation.

(24) The mode control element 74 may be arranged as a touch-sensitive and/or a proximity-sensitive control element 74. The mode control element 74 may include at least one switch, button, proximity sensor, touch sensor, etc. Preferably, the mode control element 74 is also operable to confirm a selected length setting. However, in alternative embodiments, a separate control element for confirming the selected adjustment state may be provided. Further, in another exemplary embodiment, separate activation and deactivation switches for the length adjustment mode may be provided.

(25) The sensor unit 66 may be arranged to detect multi-dimensional movements and orientation changes of the appliance 10. However, it may be advisable to focus on selected movement components so as to further simplify and clarify the control of the length adjustment drive 50. For instance, a pitch movement which basically corresponds to the movement indicated by the curved double arrow 70 in FIG. 4 may be used to control the adjustment operation. For instance, a forward pitch movement (tip-down movement or counterclockwise movement in FIG. 4) may trigger a length enlargement. By contrast, a rearward pitch movement (tip-up movement or clockwise movement in FIG. 4) may initiate a length reduction. Also an opposite assignment between rotation characteristics and length adjustment may be envisaged.

(26) The sensor unit 66 may be coupled with the control unit 64. The control unit 64 may be provided with an adjustment control signal that is delivered from the sensor unit 66. The adjustment control signal may be also referred to as user input signal. The control unit 64 may monitor the sensor unit 66. The control unit 64 may comprise a processing unit. The control unit 64 may convert the detected adjustment control signal into an actuator operating signal that may be transferred to the actuator 52. Consequently, there is no direct electric power transmission link or direct force transmission link between the movable comb portion 40 and the sensor unit 66. Rather, electric/electronic signals may be transferred from the sensor unit 66 to the actuator 52 via the control unit 64.

(27) As indicated above, the adjustment control signal obtained by the sensor unit 66 may be indicative of extended information, such as input speed, input acceleration, input displacement, input direction and respective information derivable therefrom. Based on the extended information, the control unit 64 may process a resulting actuator operating signal that can be used to operate the actuator 52.

(28) The appliance 10 may be moved in opposite longitudinal directions and/or angular directions, and the control unit 64 may be configured to derive a corresponding user input direction from the adjustment control signal. As a result, the control unit 64 may operate the actuator 52 of the displacement drive 50 so as to either extend or retract the movable comb portion 40, depending on the user input detected direction.

(29) Alongside the detection of the user input direction, the control unit 64 may derive a desired length adjustment value from the adjustment control signal. The length adjustment value may be derived from the input (angular) speed and/or the input (angular) length sensed by the sensor unit 66. Consequently, the control unit 64 may operate the actuator 52 accordingly so as to induce a desired length adjustment action.

(30) Further reference is made to FIG. 5, illustrating a perspective view of a haircutting appliance 10 shown in a state grasped and held by a user's hand 78. For ease of reference, a coordinate system 80 is shown in FIG. 5. The coordinate system 80 involves three main axes X, Y, Z.

(31) Similarly, main axes of the appliance 10 are illustrated in FIG. 5. The main axes cross one another in a central portion 82 of the housing 12 of the appliance 10. The axes involve a longitudinal axis 90 which is basically parallel to the X-axis. Further, a lateral axis 92 is provided which basically corresponds to the axis Y. Further, a height axis 94 is provided which basically corresponds to the Z-axis. The longitudinal axis 90 describes a main elongation extension direction of the appliance 10. The lateral axis 92 describes a lateral extension (width) direction of the appliance 10. In FIG. 5, the lateral axis 92 describes the second largest main extension direction of the appliance 10. The height axis 94 describes a smallest extension (height) direction of the appliance 10.

(32) Further, in accordance with an exemplary convention, the longitudinal axis 90 may be referred to as roll axis. The lateral axis 92 may be referred to as pitch axis. The height axis 94 may be referred to as yaw axis 104.

(33) The axes 90, 92, 94 are basically perpendicular to one another. A rotation about the axis 90 may be referred to as roll movement, refer to the curved double arrow 100. A rotation about the axis 92 may be referred to as pitch movement, refer to the curved double arrow 102. A rotation about the axis 94 may be referred to as yaw movement, refer to the curved double arrow 104.

(34) A multi-dimensional movement of the appliance 10 may be described with reference to the axes 90, 92, 94 which represent three translational degrees of freedom and three rotational degrees of freedom. Hence, the movement may involve a translational movement along at least one of the axis 90, 92, 94. Further, a rotational movement about at least one of the axes 90, 92, 94 may be involved.

(35) In an exemplary embodiment, the sensor unit 66 (refer to FIG. 4) is capable of detecting the pitch movement 102 of the appliance which may be induced by a wrist movement of the user. The pitch movement 102, depending on the rotation direction, may cause an extraction and/or a retraction of the movable comb portion which is shown in FIG. 5 in two states (retracted state 40, solid lines, and extracted state 40, dashed lines).

(36) An association of the pitch movement 102 and the respective length adjustment procedure for the spacing comb 26 is intuitive and easy to learn for the user. Hence, by moving the appliance 10, the user may readily notice a result, namely a corresponding movement of the movable comb portion 40, refer to the adjustment movement axis 58.

(37) As indicated above, in at least some embodiments, the adjustment drive 50 is augmented by a mode control element 74 (refer to FIG. 4). Hence, the user may deliberately activate and deactivate a length adjustment mode. In FIG. 5, the mode control element 74 is hidden and/or covered by the housing portion 12 of the appliance 10.

(38) FIG. 6 shows a schematic perspective rear view of another exemplary embodiment of a hair cutting appliance 110, particularly an electrically operated hair cutting appliance. FIG. 7 is a simplified partial side view of a frontal portion of the appliance 110.

(39) The appliance 110 may also be referred to as hair clipper or hair trimmer. The appliance 110 comprises a housing or housing portion 112 having a generally elongated shape. At a first, top end thereof, a cutting unit 114 is provided. The cutting unit 114 comprises a blade set assembly 116. The blade set assembly 116 comprises a stationary blade 120 and a movable cutter blade 122 that may be moved with respect to each other to cut hair. At a central portion and a second, bottom end of the housing 112, a handle or grip portion is formed. A user may grasp or grab the housing 112 at the grip portion. The appliance 110 in accordance with the exemplary embodiment of FIG. 6 further comprises operator controls. For instance, an on-off switch or button 124 may be provided.

(40) For illustrative purposes, the housing 112 of the hair cutting appliance 110 comprises a top side, where the blade set 116 is mounted, a bottom side that is opposite to the top side, a front side which typically faces the skin of the to-be-groomed subject when the appliance 110 is in operation, and a rear side that is opposite to the front side. These and other positional and/or directional indications shall not be construed as limiting the scope of the disclosure.

(41) In accordance with the embodiment illustrated in FIGS. 6 and 7, a cutting length adjustment mechanism 130 for the blade set 116 is provided. Hence, the cutting length adjustment mechanism 130 is arranged as a tip-to-tip adjustment mechanism for the stationary blade 120 and the movable cutter blade 122 of the blade set 116.

(42) The adjustment mechanism 130 is motor powered. Generally, the adjustment mechanism 130 may be arranged as a tip to tip adjustment mechanism that sets and adjusts a distance between the tips of the stationary blade 120 and the cutter blade 122. Hence, an offset in the frontal direction between toothed leading edges of the stationary blade 120 and the cutter blade 122 may be adjusted. When the stationary blade 120 is at least partially tapered toward the frontal end, the tip to tip adjustment also involves a cutting length adjustment.

(43) Further reference in this context is made to FIG. 7, schematically illustrating an operation of an adjustment mechanism 130. FIG. 7 shows a simplified view of a cutting unit 114 of a hair cutting appliance 110. At or adjacent to the cutting unit 114, the appliance 110 is provided with the adjustment mechanism 130 that may be generally arranged in a fashion similar to the embodiments of the adjustment mechanism 24 explained with reference to FIGS. 3 and 4. In FIGS. 3 and 4, a movable comb portion 40 is provided which is actuated by an adjustment drive. In FIG. 7, an adjustment drive 150 is indicated which is operable to actuate the stationary blade 120 with respect to the housing 112 and/or the cutter blade 122 of the appliance 110. Hence, the stationary blade 120 may be referred to as movable portion of the adjustment mechanism 130.

(44) The stationary blade 120 can be moved by the adjustment mechanism 130 between a first state and a second state. In FIG. 7, the first state is indicated by continuous lines. The second state is indicated by dashed lines. The first state is associated with a first, retracted state of the stationary blade 120. The second state is associated with a second, extracted state of the stationary blade 120 which is indicated in FIG. 7 by dashed lines. A double arrow designated by reference numeral 136 indicates the adjustment movement between the stationary blade 120 and the cutter blade 122. Hence, a distance between the leading edges of the stationary blade 120 and the cutter blade 122 can be adjusted which involves a cutting length adjustment, as the stationary blade 120 is slightly tapered towards the frontal end.

(45) The stationary blade 120 and the movable cutter blade 122 of the blade set 116 are arranged in such a way that a sliding adjustment movement therebetween in the adjustment movement direction 136 in enabled.

(46) In respect of the detailed design and configuration of the adjustment mechanism 130 and in respect of control approaches in the context of the adjustment (length setting) operation, explicit reference is made to the embodiments discussed herein that implement an adjustment mechanism for an adjustable spacing comb. Features and aspects discussed in connection therewith may be readily implemented in the general arrangement of a tip-to-tip adjustment mechanism as shown in FIGS. 6 and 7.

(47) Further reference is made to FIG. 8, illustrating an exemplary method of operating a cutting length adjustment mechanism, particularly an adjustable spacing comb or an adjustable blade set, for a hair cutting appliance. The method involves a step S10 comprising a provision of an adjustment drive which involves an actuator that is capable of actuating/driving a movable portion of the cutting length adjustment mechanism with respect to a housing portion of the appliance. Consequently, the cutting length adjustment mechanism may be referred to as a powered or motorized cutting length adjustment mechanism.

(48) The method may further include a step S12 which comprises a provision of a movement sensor unit. The movement sensor unit is configured to detect a movement of the hair cutting appliance, particularly an overall movement of a housing of the appliance. The movement of the appliance involves at least one of an orientation change and a position change. The movement sensor unit comprises at least one movement sensor which may be arranged as an acceleration sensor and/or a gravity sensor. Further types of movement sensors may be envisaged.

(49) Generally, the movements of the appliance that are detected by the movement sensor unit may be used to control the actuator and, as a consequence, the adjustment operation of the cutting length adjustment mechanism. In other words, a user may grasp the appliance and may move the housing thereof which may particularly involve a rotation. In this way, the user may define a desired length setting of the spacing comb or the adjustable blade set without the need of actuating complex input and control elements. An intuitive control of the length adjustment and the resulting length setting is enabled in this way.

(50) The method further includes a step S14 comprising an activation of a length adjustment operation. This may involve operating a mode control element, for instance a mode control switch or sensor. Once the length adjustment mode is activated, an overall movement of the appliance may trigger a respective length adjustment procedure.

(51) The method may proceed with a step S16. The step S16 involves a deliberate defined control movement of the appliance by the user. For instance, the movement may involve a pitch movement, e.g. a rotation of the housing of the appliance about a pitch axis that is perpendicular to a main adjustment direction or travel direction of the spacing comb or the adjustable blade set.

(52) In a corresponding step S18, absolute and/or relative movements of the appliance may be detected by the movement sensor unit. In a further step S20, an input operation (i.e. the overall control movement) may be converted into a corresponding control command for the actuator of the adjustment drive. Hence, the step S20 may result in the provision of a control command or signal that represents a defined length adjustment value or operation.

(53) In a subsequent step S22, the actuator for the adjustment drive may be operated accordingly. Hence, a movable portion of the cutting length adjustment mechanism may be moved at a defined adjustment speed, for a predefined operation time and/or to a defined adjustment position.

(54) As a consequence, in a further step S24, the length adjustment is accomplished as the movable portion is moved in accordance with the adjustment command signal. The step S24 may also involve a deactivation of the length adjustment mode. This may further involve a confirmation of a present adjustment state.

(55) While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

(56) In the claims, the word comprising does not exclude other elements or steps, and the indefinite article a or an does not exclude a plurality. A single element or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

(57) Any reference signs in the claims should not be construed as limiting the scope.