Adjustable spacing comb, adjustment drive and hair cutting appliance

Abstract

An adjustment drive for an adjustable spacing comb for a hair cutting appliance that may be fitted with an adjustable spacing comb. The adjustment drive comprises an actuator for actuating a movable comb portion of the adjustable spacing comb with respect to a blade set of the hair cutting appliance, a manually operable rotation element, and a rotary encoder, that is configured to detect rotary movement of the rotation element and to output a respective user input signal, wherein the actuator is operated in response to the user input signal.

Claims

1. An adjustment drive for an adjustable spacing comb for a hair cutting appliance comprising: a housing portion, a cutting unit including a blade set, the adjustable spacing comb including: a movable comb portion movable with respect to the housing portion of the hair cutting appliance, the adjustment drive, and a manually operable rotation element configured to receive manually applied rotary movements by a user, the rotation element being rotatingly mounted to the adjustment drive and supported at the housing portion of the hair cutting appliance, the rotation element being at least partially covered by the housing portion, wherein a circumferential portion of the rotation element is accessible through an opening portion of the housing portion, the adjustment drive being manually operable by the rotation element, the adjustment drive comprising: an actuator configured for actuating the movable comb portion of the adjustable spacing comb with respect to a blade set of the hair cutting appliance, a rotary encoder directly coupled to the rotation element and configured to detect rotary movements of the rotation element applied by a user, the rotary encoder being further configured to output a respective user input signal corresponding to the detected rotary movements applied by the user to the rotation element, and a control unit respectively coupled to the actuator and to the rotary encoder, wherein the control unit is configured to convert the detected user input signal output from the rotary encoder into an actuator operating signal, output by the control unit to the actuator to enable the control unit to electronically control the movable comb portion in response to the detected user inputs, wherein the control unit is further configured to move the movable comb portion in accordance with an adjustment position speed calculated as a function of a difference between relative positions between the rotation element and the movable comb portion.

2. The adjustment drive as claimed in claim 1, wherein the control unit is configured to operate the movable comb portion of the adjustable spacing comb on the basis of the formula:
V.sub.comb=K.sub.gain*(X.sub.wheelX.sub.comb), wherein V.sub.comb is the adjustment speed of the movable comb portion, wherein K.sub.gain is a coefficient, wherein X.sub.wheel is the rotational position of the rotation element, and wherein X.sub.comb is the position of the movable comb portion.

3. The adjustment drive as claimed in claim 1, wherein the rotation element is a flywheel rotation element, and wherein the rotation element comprises a circumferential portion that is tangible for the user.

4. The adjustment drive as claimed in claim 1, wherein the rotation element is a high-density rotation element comprising a moment of inertia.

5. The adjustment drive as claimed in claim 1, wherein the rotation element comprises a circumferential surface patterning.

6. The adjustment drive as claimed in claim 5, wherein the rotation element is at least partially covered by the housing portion, wherein a circumferential portion of the rotation element is accessible through and opening portion of the housing portion.

7. The adjustment drive as claimed in claim 5, wherein the circumferential surface patterning is a circumferential knurling.

8. The adjustment drive as claimed in claim 1, wherein the encoder is arranged as an absolute encoder such that a distinct turning angle of the rotation element is associated with a distinct absolute position of the movable comb portion with respect to the blade set.

9. The adjustment drive as claimed in claim 1, wherein the encoder is arranged as an incremental encoder such that incremental (rotational) position changes of the rotation element is associated with incremental position changes of the movable comb portion with respect to the blade set.

10. The adjustment drive as claimed in claim 1, wherein the adjustment drive is further configured to provide feedback to a user, wherein a type of feedback is selected from a group consisting of tactile feedback, audio feedback, visual feedback, and combinations thereof, wherein the tactile feedback is provided via one of vibrations generated by the actuator or by a separate vibrating element, wherein audio feedback is provided via an audible alarm, and wherein visual feedback is provided via the adjustable spacing comb.

11. The adjustment drive as claimed in claim 1, wherein the rotation element is rotatably, supported at the housing portion of hair cutting appliance.

12. A hair cutting appliance, comprising: a housing portion, a cutting unit including a blade set, an adjustable spacing comb including a movable comb portion movable with respect to the housing portion of the hair cutting appliance, an adjustment drive configured for adjusting the adjustable spacing comb for the hair cutting appliance, and a manually operable rotation element rotatingly mounted to the adjustment drive, wherein the rotation element is rotatably supported at the housing portion of the hair cutting appliance and is at least partially covered by the housing portion, wherein a circumferential portion of the rotation element is accessible through an opening portion of the housing portion, the adjustment drive comprising: an actuator configured for actuating a movable comb portion of the adjustable spacing comb with respect to the blade set of the hair cutting appliance, a rotation element rotatingly mounted to the adjustment drive and configured to receive from a user manually applied rotary movements of the rotation element, a rotary encoder directly coupled to the rotation element and configured to detect the user inputs applied by the user to the rotation element, the rotary encoder further configured to output a respective user input signal corresponding to the detected the manually applied rotary movements of the rotation element by the user to the rotation element, and a control unit respectively coupled to the actuator and to the rotary encoder, wherein the control unit is configured to convert the detected manually applied rotary movements of the rotation element applied by the user output from the rotary encoder into an actuator operating signal, output by the control unit to the actuator to enable the control unit to electronically control the movable comb portion in response to the detected said user manually applied rotary movements of the rotation element, wherein the control unit is further configured to move the movable comb portion in accordance with an adjustment position speed calculated as a function of a difference between the relative positions between the rotation element and the movable comb portion.

13. The hair cutting appliance as claimed in claim 12, wherein the rotation element is mechanically unassociated with the actuator of the adjustment drive, particularly wherein the rotation element is mounted in a manner that is rotationally independent from the actuator.

14. The hair cutting appliance as claimed in claim 12, wherein the rotation element is arranged at a location of the housing portion positioned to be accessible to a user without consideration of the position of or proximity to the adjustment drive of the adjustable spacing comb.

15. The hair cutting appliance as claimed in claim 12, wherein the hair cutting appliance is a hair trimmer.

16. The hair cutting appliance as claimed in claim 12, wherein the hair cutting appliance is a hair clipper.

17. A method for operating an adjustable spacing comb for a hair cutting appliance as claimed in claim 12, comprising the following steps: providing the adjustment drive comprising the actuator for actuating the movable comb portion of the adjustable spacing comb, providing the manually operable rotation element, detecting rotary movement of the rotation element, wherein the rotary movement is induced by a user input motion, generating and outputting a respective user input signal, and operating the actuator in response to the user input signal; wherein the actuator is operated based on a difference between a position of the rotation element and a position of the movable comb portion, preferably on a difference between a normalized position of the rotation element and a normalized position of the movable comb portion such that the adjustment speed of the moveable comb portion is a function of said difference.

18. An adjustable spacing comb for a hair cutting appliance, comprising an adjustment drive, the adjustment drive comprising: an actuator configured for actuating the movable comb portion of the adjustable spacing comb with respect to a blade set of the hair cutting appliance, a rotary encoder directly coupled to the rotation element and configured to detect rotary movement of the rotation element, and in particular the user inputs applied by the user to the rotation element, the rotary encoder being further configured to output a respective user input signal corresponding to the detected user inputs applied by the user to the rotation element, and a control unit respectively coupled to the actuator and to the rotary encoder, the control unit being configured to convert the detected user input signal output from the rotary encoder into an actuator operating signal, output by the control unit to the actuator to enable the control unit to electronically control the movable comb portion in response to the detected user inputs, the control unit being further configured to move the movable comb portion in accordance with an adjustment position speed calculated as a function of a difference between relative positions between the rotation element and the movable comb portion.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and other aspects of the invention 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 yet another 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 shows a simplified top view of another exemplary embodiment of a hair cutting appliance fitted with an adjustable spacing comb and an adjustment drive for the spacing comb;

(7) FIG. 6 shows a simplified top view of another exemplary embodiment of a hair cutting appliance fitted with an adjustable spacing comb and an adjustment drive for the spacing comb;

(8) FIG. 7 shows a simplified schematic partial view of a housing portion of a hair cutting appliance wherein a rotation element for user inputs is shown in a partially covered state;

(9) FIG. 8 shows a schematic simplified view of an exemplary rotation element for user inputs that is coupled with an encoder for detecting rotary movement of the rotation element;

(10) FIG. 9 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 a rotation element for operating an adjustment drive for the spacing comb;

(11) FIG. 10 is a schematic perspective view of yet another exemplary hair cutting appliance fitted with an adjustable spacing comb, wherein a rotation element for operating an adjustment drive for the spacing comb is arranged at a position that is different from the position illustrated in FIG. 9;

(12) FIG. 11 shows an illustrative block diagram representing several steps of an embodiment of an exemplary method for operating an adjustable spacing comb for a hair cutting appliance in accordance with several aspects of the present disclosure, and

(13) FIG. 12 shows yet another illustrative block diagram representing several steps of an exemplary algorithm for operating an adjustment drive for an adjustable spacing comb.

DETAILED DESCRIPTION OF EMBODIMENTS

(14) 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 12 at the grip portion 18.

(15) 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 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.

(16) 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. By way of example, the spacing comb 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 inserted into respective slots at a mounting portion 30 of the housing portion 12. The sliding beams 34-1, 34-2 may be inserted into respective slots at the mounting portion 30. The attachment portion 28 may further comprise at least one snap-on member 36. The snap-on member 36 may secure the spacing comb 26 in its mounted state.

(17) 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 teeth of the toothed portion 32 may comprise a slot in which the blade set 16 may be movably arranged in the attached state.

(18) 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 back 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 appliance 10 are visible.

(19) 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 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 motorized adjustment drive 50.

(20) 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.

(21) 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 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.

(22) For operating the adjustment drive 50, respective control elements may be provided. To this end, the adjustment drive 50 may comprise an input rotation element 64, particularly a manually operable rotation element 64. Generally, the rotation element 64 may be formed in a basically rotationally symmetrical fashion. The rotation element 64 may be rotationally mounted. More particularly, the rotation element 64 may be mounted to the housing portion 12 or to an intermediate component that is attached to the housing portion 12. Generally, the rotation element 64 may be arranged to be rotated about a rotation axis 66, refer also to the curved double-arrow denoted by reference numeral 68 in FIG. 3. A user may operate or drive the rotation element 64 so as to control the adjustment drive 50 and, consequently, to adjust the movable comb portion 40 to a desired cutting length.

(23) The rotation element 64 may be referred to as flywheel rotation element 64. The rotation element 64 may have a considerably high moment of inertia. Consequently, the user may set the rotation element 64 into rotation. Due to the moment of inertia, the rotation element 64 may basically maintain its rotation for a considerable time period. Consequently, a user may push or pull the rotation element 64 which may involve a single driving stroke. The rotation element 64 may then rotate passively for a considerably larger time period.

(24) The rotation element 64 is coupled to an encoder 70. The encoder 70 may be configured to detect rotary or rotational movement of the rotation element 64. By way of example, the encoder 70 may comprise a Hall-sensor or a similar customary rotation sensor. Consequently, the encoder 70 may detect and output a user signal which is derivable from the user's driving stroke applied to the rotation element 64. The user input signal may be transferred to a control unit 74. The control unit 74 may comprise a processing unit. The control unit 74 may convert the detected user input signal into an actuator operating signal that may be transferred to the actuator 52. Consequently, there is no power transmission or force transmission link between the actuator 52 and the rotation element 64. Rather, electric signals may be transferred from the encoder 70 to the actuator 52 via the control unit 74.

(25) The rotation element 64 may extend the range of possible user inputs that may be detected by a single operating element. As indicated above, the user may, on the one hand, precisely rotate the rotation element for precisely positioning the movable comb portion 40. On the other hand, the user may vigorously actuate the rotation element 64 which may cause significant rotation of the rotation element 64. Consequently, the movable comb portion 40 may cover long distances. In each case, the act of adjusting is user-friendly and time-efficient.

(26) Further reference is made to FIG. 4. An extracted state of the movable comb portion 40 is indicated in FIG. 4 by a respective dashed line. As can be further seen from FIG. 4, a substantial portion of the rotation element 64, particularly a substantial circumferential portion, may be covered by the housing 12 of the hair cutting appliance 10. Consequently, a minor circumferential portion of the rotation element 64 may be accessible for the user. As can be further seen from FIG. 4, the rotation element 64 may comprise a circumferential mass accumulation 76. This may increase the moment of inertia of the rotation element 64.

(27) With particular reference to FIGS. 5 and 6, further exemplary arrangements of location detection units for hair cutting appliances 10 are illustrated and further described. With respect to their general design and layout, the hair cutting appliances 10 of FIGS. 5 and 6 may basically correspond the hair cutting appliance 10 illustrated in FIG. 3. In FIG. 5, the rotation axis 66 of the rotation element 64 is generally parallel or only slightly inclined with respect to a longitudinal extension of the elongated housing portion 12 of the hair cutting appliance 10. Generally, the housing portion 12 may extend from a first end and a second end which is opposite to the first end. At the first end of the housing portion 12, an adjustable spacing comb 26 may be attached. The second end of the housing portion 12 may also be referred to as handle end. The rotation axis 66 may at least partially extend through an opening in the housing portion 12.

(28) Similarly, the rotation axis 66 of the rotation element 64 shown in FIG. 6 is generally parallel or only slightly inclined with respect to a longitudinal extension of the elongated housing portion 12. In FIG. 6, the rotation element 64 itself forms a handle end of the housing portion 12. Consequently, the handle end (formed by the rotation element 64) may be set into rotation with respect to the (remaining) housing portion 12, refer to a curved arrow denoted by reference numeral 68. The rotation element 64 of FIG. 6 is generally arranged as a rotational paraboloid or, more generally, as a rotationally symmetrical rotation element 64. However, at least in some embodiments, the rotation element 64 may be at least slightly flattened or similarly deformed.

(29) Further reference is made in this connection to FIG. 7. FIG. 7 shows a simplified perspective view of a housing surface 62 of a housing portion 12 of a hair cutting appliance 10, refer also to FIG. 4. The housing surface 82 may comprise an aperture or opening 84. Only a relatively small circumferential portion of the rotation element 64 may extend through the opening 84. A respective circumferential portion 86 that is accessible for the user is indicated in FIG. 7 by reference number 86. Generally, the rotation element 64 may comprise a non-slip surface 88. Particularly, the rotation element 64 or at least a circumferential portion 86 thereof may be formed from a material that provides a high friction coefficient. In the alternative, the circumferential portion 86 of the rotation element 64 may be coated with a respective high-friction material. By way of example, rubber or rubber-like materials have considerably high coefficients of friction.

(30) FIG. 8 shows a schematic view of a rotatingly mounted rotation element 64 that is coupled with an encoder 70, particularly a rotatory encoder 70. In some embodiments, the rotation element 64 may comprise a cylindrical shape or a tubbish shape. Generally, the rotation element 64 may comprise a rotationally symmetric shape. At the circumferential portion 86 of the rotation element 64, a structured pattern 90, particularly a knurling pattern, may be provided. Generally, a number of recesses and/or indentations may be provided at the circumferential portion 86 which may improve the grip for the user. Knurling may involve diamond knurling, linear knurling or similar shapes.

(31) As exemplarily shown in FIG. 8, the rotation element 64 may be coupled to a respective shaft or axis 66 that is mounted to at least one bearing 92-1, 92-2 for rotation, refer to the curved arrow denoted by reference numeral 68 in FIG. 8. Via the axis 66, the rotation element 64 may be coupled to the encoder 70. The encoder 70 may comprise a wheel 96 which may rotate with the rotation element 64. Furthermore, a detector or transceiver 98 may be provided that detects rotatory motion of the wheel 96 and, consequently, of the rotation element 64. It goes without saying that the detector or transceiver 98 may also be configured to directly detect rotatory motion at the rotation element 64 itself.

(32) In still another embodiment, the rotation element 64 may be further coupled to a click mechanism 102. The click mechanism 102 may comprise a wheel 104, particularly a polygonal wheel or toothed wheel 104. The wheel 104 may be mounted to the axis 66 and may be further arranged to cooperate with a clicker element 106, particularly a clicker spring. The clicker element 106 may be coupled to or mounted at the housing portion 12, refer also to FIGS. 3 to 7. The clicker element 106 may engage the wheel 104. During rotation of the rotation element 64, the wheel 104 may also rotate with respect to the clicker element 106. Consequently, the clicker element 106 may alternatingly engage and disengage respective protrusions and indentations at the wheel 104. This may cause respective click noises. The click mechanism 102 may further inhibit excessive rotational motion of the rotation element 64. This may be beneficial to ensure that the rotation element 64 stops within respective time limits.

(33) With further reference to FIG. 9 and FIG. 10, various positions of the rotation element 64 at the housing portion 12 of hair cutting appliances 10 are described. FIG. 9 shows a perspective view of a hair cutting appliance 10 held by a user. The user may operate the rotation element 64 with its thumb. As can be further seen from FIG. 9, the rotation element 64 may comprise a rotation axis 66 that is basically perpendicular to a general elongation direction of the housing portion 12. Operating the rotation element 64 and, consequently, the adjustment drive 50 (covered by the housing 12 in FIG. 9) may induce a respective extraction or retraction of the adjustable spacing comb 26 that is attached to the housing 12, refer also to the double-arrow denoted by reference numeral 58 in FIG. 9 and FIG. 10.

(34) As can be further seen from FIG. 9, the rotation element 64 is arranged at a position of the housing portion 12 that may also be referred to as a central position. By contrast, FIG. 10 illustrates an arrangement of a respective rotation element 64 at a position of the housing portion 12 that may be referred to as lower portion and/or portion that is close to the second end of the housing portion 12. Since no mechanical (force transmission) link is required between the rotation element 64 and the actuator 52 of the adjustment drive 50 (not shown in FIGS. 9 and 10), the rotation element 64 may be arranged at arbitrary positions of the housing portion 12.

(35) FIG. 10 further illustrates an alternative arrangement or an alternative orientation of a rotation element 64a which is indicated by dashed lines. A respective rotation axis 66a may be generally parallel to or only slightly inclined with respect to a main longitudinal extension of the housing portion 12. The rotation element 64a may be mounted in the housing portion 12 and at least slightly extend through an opening in the housing portion 12. The rotation element 64a may be actuated for rotation with respect to the housing portion 12, refer to the curved arrow denoted by reference numeral 68a in FIG. 10.

(36) With further reference to FIG. 11, an exemplary method of operating an adjustable spacing comb for a hair cutting appliance is illustrated and further described. The method may comprise a step S10 which may involve providing an adjustment drive that comprises an actuator for actuating a movable comb portion of an adjustable spacing comb of a hair cutting appliance. Preferably, the adjustment drive is shaped in accordance with at least some embodiments as disclosed herein. A further step S12 may follow which involves providing a manually operable rotation element, particularly a manually rotatable rotation element which is at least partially accessible for a user through an opening in a housing portion of the hair cutting appliance. A further step S14 may follow which may involve the detection of user inputs, particularly of rotatory movement of the rotation element which is induced by a user input motion, such as an accelerating input stroke. In a subsequent step S16, based on the detected rotary movement, a respective user input signal may be generated and provided for further processing. At still another step S18, the actuator of the adjustment drive may be operated on the basis of the user input signal. The step S18 may involve the conversion of the user input signal into an actuator operating signal. To this end, a control unit may be provided.

(37) FIG. 12 illustrates several steps of a simplified algorithm for the detection of user inputs and for operating a movable comb portion of an adjustable spacing comb in accordance with the detected user inputs. A first step S20 may involve a user input action, particularly an actuation of a rotation element by the user. A further step S22 may follow which may involve the detection that a (normalized) position of the rotation element with respect to a (normalized) position of the movable comb portion has been altered. As already indicated above, the position of the rotation element and the position of the movable comb portion may be normalized to make them comparable. For instance, a normalized positional range may comprise values between 0 and 1.

(38) In a further step S24, a desired moving speed of the movable comb portion in response to the detected user input may be calculated. Consequently, an operating signal may be generated that may be used to operate an actuator for moving the movable comb portion. A further step S26 may follow which may stop the movement of the movable comb portion when it is determined that the actual (normalized) position of the movable comb portion corresponds to the (normalized) position of the rotation element. The steps S20 to S26 may form a loop.

(39) 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.

(40) 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.

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