ADJUSTABLE SPACING COMB, ADJUSTMENT DRIVE AND HAIR CUTTING APPLIANCE

Abstract

The present disclosure relates to an adjustment drive (58) for an adjustable spacing comb (26) for a hair cutting appliance (10) and to a hair cutting appliance (10) that is fitted with an adjustable spacing comb (26). The adjustment drive (58) comprises an actuator (60) that is configured for actuating a movable comb portion (40) of the adjustable spacing comb (26) with respect to a blade set (16) of the hair cutting appliance (10), a drivetrain (62) for coupling the actuator (60) and the movable comb portion (40), wherein the drivetrain (62) comprises a reduction gear unit (66), and a location detection unit (80) comprising a rotary encoder (84), wherein the rotary encoder (84) is coupled to an output shaft (68) of the reduction gear unit (66).

Claims

1. An adjustment drive for an adjustable spacing comb for a hair cutting appliance, comprising: an actuator that is configured for actuating a movable comb portion of the adjustable spacing comb with respect to a blade set of the hair cutting appliance, wherein the actuator is an electromotor, a drivetrain that is configured for coupling the actuator and the movable comb portion, wherein the drivetrain comprises a reduction gear unit, and a location detection unit comprising a rotary encoder, wherein the rotary encoder is coupled to an output shaft of the reduction gear unit, and wherein the rotary encoder is configured to output an electric signal.

2. The adjustment drive as claimed in claim 1, wherein the actuator is a high-speed electromotor, and wherein the reduction gear unit comprises at least one reduction gear stage, particularly at least one backlash-afflicted gear stage.

3. The adjustment drive as claimed in claim 1, wherein the output shaft of the reduction gear unit comprises a first toothed section and a second toothed section, wherein the first toothed section is arranged to be coupled with the movable comb portion, and wherein the second toothed section is arranged to be coupled with the rotary encoder.

4. The adjustment drive as claimed in claim 1, wherein the output shaft of the reduction gear unit is arranged to be coupled with a translatory movement element for driving the movable comb portion, particularly a translation screw element or a toothed rack element.

5. The adjustment drive as claimed in claim 4, wherein the translatory movement element comprises a main extension direction that is inclined with respect to a longitudinal extension direction of the output shaft.

6. The adjustment drive as claimed in claim 3, wherein the output shaft of the reduction gear unit comprises a crown gear or bevel gear section and a spur gear section, wherein the crown gear or bevel gear section is arranged to be coupled with the movable comb portion, and wherein the spur gear section is arranged to be coupled with the rotary encoder.

7. The adjustment drive as claimed in claim 6, wherein the crown gear or bevel gear section and the spur gear section are arranged to engage their respective counterpart gear sections that are associated with the movable comb portion and the rotary encoder with low-backlash.

8. The adjustment drive as claimed in claim 1, wherein the location detection unit further comprises a detector shaft that is arranged between the output shaft and the rotary encoder.

9. The adjustment drive as claimed in claim 1, wherein the rotary encoder is a high resolution rotary encoder, particularly a rotary encoder that is capable of detecting angular signals at a minimum angular resolution of at least 9 (degrees).

10. The adjustment drive as claimed in claim 1, further comprising a control unit that is coupled to the actuator and to the rotary encoder, wherein the control unit is arranged to operate the actuator on the basis of location signals that represent an actual position of the movable comb portion detected by the location detection unit.

11. The adjustment drive as claimed in claim 10, wherein the control unit is capable of operating the adjustment drive such that the movable comb portion is precisely adjustable, wherein achieved incremental length adjustment steps are in the range of about 0.1 mm to about 0.5 mm.

12. The adjustment drives as claimed in claim 10, wherein the adjustment drive is capable of adjusting the movable comb portion with high overall repeatability, wherein overall length adjustment repeatability is in the range of about 0.1 mm to about 0.5 mm.

13. The adjustment drive as claimed in claim 1, wherein the reduction gear unit is a low cost reduction gear unit, wherein at least some gears of the reduction gear unit are at least partially made from plastic material.

14. (canceled)

15. A hair cutting appliance, particularly a hair trimmer or clipper, comprising a housing portion, a cutting unit including a blade set, and an adjustable spacing comb comprising a movable comb portion that is movable with respect to a housing portion of the hair cutting appliance, and an adjustment drive as claimed in claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] These and other aspects of the disclosure will be apparent from and elucidated with reference to the embodiments described hereinafter. In the following drawings

[0041] FIG. 1 shows a schematic perspective view of an exemplary electric hair cutting appliance and an adjustable spacing comb for the hair cutting appliance, wherein the spacing comb is shown in a detached state;

[0042] FIG. 2 shows a partial exploded perspective view of another embodiment of a hair cutting appliance and an adjustable spacing comb, wherein the spacing comb is shown in an insertion orientation;

[0043] FIG. 3 is a schematic perspective view of yet another embodiment of a hair cutting appliance fitted with an adjustable comb, the hair cutting appliance being held by a user that may operate a control element for comb length adjustment;

[0044] FIG. 4 is a schematic perspective view of yet another embodiment of a hair cutting appliance fitted with an adjustable spacing comb, the hair cutting appliance being held by a user that may operate a control element for operating an adjustment drive for the spacing comb, wherein the control element is different from a respective control element shown in FIG. 3;

[0045] FIG. 5 shows a simplified top view of an embodiment of hair cutting appliance fitted with an adjustable spacing comb and an adjustment drive for the spacing comb;

[0046] FIG. 6 shows a simplified side view of an embodiment of a hair cutting appliance fitted with a retractable spacing comb and an adjustment drive for adjusting the spacing comb; and

[0047] FIG. 7 shows another simplified top view of yet another embodiment of a hair cutting appliance fitted with an adjustable spacing comb and an adjustment drive for the spacing comb.

DETAILED DESCRIPTION OF EMBODIMENTS

[0048] 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.

[0049] 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.

[0050] 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.

[0051] As can be further seen from FIG. 2, the spacing com 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.

[0052] With further reference to FIG. 3 and FIG. 4, exemplary embodiments of the hair cutting appliances 10 are illustrated that are fitted with a respective adjustable spacing comb 26. FIG. 3 and FIG. 4 show perspective views of hair cutting appliances 10 in a state held by a user. The hair cutting appliances 10 may further comprise an adjustment drive for the adjustable spacing comb 26 (not shown in FIG. 3 and FIG. 4). The user may actuate the adjustment drive by operating the length adjustment control 22. Generally, the adjustable spacing comb 26 or, more particularly, a movable comb portion 40 (refer to FIG. 4) thereof may be moved with respect to the blade set 16 of the hair cutting appliance 10 (refer to FIG. 1) to adjust a distance between the adjustable spacing comb 26 and the blade set 16. By way of example, the movable spacing comb 26 may be extracted or retracted in a generally longitudinal direction indicated in FIG. 3 and FIG. 4 by a double-arrow denoted by reference numeral 46. The spacing comb 26 shown in FIG. 3 is in a retracted state. FIG. 4 illustrates a refracted end and an extracted state of the movable comb portion 40 of the spacing comb 26. A respective extracted state of the movable comb portion 40 is indicated in FIG. 4 by dashed lines.

[0053] As can be seen in FIG. 3, the user may actuate the length adjustment control 22 in a basically lateral direction to cause an adjustment movement of the spacing comb 26. A double arrow denoted by reference numeral 48 indicates the lateral operating direction. FIG. 4 illustrates a differently shaped length adjustment control 22. By way of example, the length adjustment control 22 may be rotatingly arranged at the housing portion 12 of the hair cutting appliance 10. Consequently, the user may rotate or swivel the length adjustment control 22 about a rotation axis 50, refer also to a curved double arrow denoted by reference number 52 in FIG. 4. By actuating or operating the length adjustment control 22, the user may control the adjustment drive for the adjustable spacing comb 26 so as to define or set a desired cutting length.

[0054] With further reference to FIGS. 5, 6 and 7, illustrative embodiments of hair cutting appliances 10 that are fitted with adjustment drives for an adjustable spacing comb will be illustrated and further described. In FIGS. 5, 6, and 7, a respective housing portion 12 of the hair cutting appliances 10 is indicated by dashed lines. Consequently, internal components of the hair cutting appliances 10 are visible. Generally, the adjustment drives 58 are at least partially housed in or covered by the housing portion 12.

[0055] It is further worth mentioning in this regard that the views shown in FIGS. 5, 6 and 7 do not necessarily represent the same arrangement or embodiment. FIG. 5 shows a schematic top view of a hair cutting appliance 10 fitted with an adjustable spacing comb 26. FIG. 6 shows a schematic side view of a hair cutting appliance 10 fitted with a similar adjustable spacing comb 26, wherein a respective movable comb portion of the spacing comb 26 is shown in FIG. 6 in a retracted state (reference numeral 40) and in an extracted state indicated by dashed lines (reference numeral 40). FIG. 7 shows a further schematic top view of a hair cutting appliance 10 that is fitted with an adjustable spacing comb 26.

[0056] With particular reference to FIG. 5, the adjustable spacing comb 26 is further described. The adjustable spacing comb 26, refer also to FIG. 1 and to FIG. 2, may comprise sliding beams 34 that may cooperate with a carriage 42 that is movably arranged at the housing portion 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. 5, 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 driving or operating the movable comb portion 40 with respect to the blade set 16 (or to the housing 12) an adjustment drive 58 may be provided which may also be referred to as adjustment powertrain. In other words, the adjustment drive 58 may be regarded as motorized adjustment drive 58.

[0057] The adjustment drive 58 may comprise an actuator 60 or, more particularly, an electromotor. The actuator 60 may be coupled to a drivetrain 62. The drivetrain 62 may comprise a reduction gear unit 66 that is coupled to an actuator output shaft 64. The reduction gear unit 66 may comprise a plurality of gear stages, refer also to FIG. 7. The reduction gear unit 66 may comprise an output shaft 68. At the output shaft 68, a drive gear 70 may be arranged. The drive gear 70 may be coupled to a translatory movement element 54 which is configured to engage the engagement member 44 of the carriage 42. By way of example, the translatory movement element 54 may be arranged as a spindle element or a rack element. Generally, the translatory movement element 54 may be arranged to convert a rotational input motion applied by the drive gear 70 of the output shaft 68 of the reduction gear unit 66 into a longitudinal adjustment movement of the movable comb portion 40, refer to the double-arrow 46 in FIGS. 5, 6 and 7.

[0058] By way of example, the translatory movement element 54 may comprise a driveable gear wheel 72 which may be configured to engage the drive gear 70, refer also to FIG. 6. In some embodiments, the translatory movement element 54 may be inclined with respect to the output shaft 68 of the reduction gear unit 66, as can be also seen from FIG. 6. This may improve the handling of the hair cutting appliance 10 since in this way the housing portion 12 may be shaped in a user-friendly fashion providing a proper ergonomic design. As can be seen from FIG. 6, the overall extension of the housing portion 12 may be slightly curved or banana-shaped.

[0059] Generally, the drive gear 70 of the output shaft 68 of the reduction gear unit 66 may be further coupled to a location detection unit 80. Consequently, an actual position of the movable comb portion 40 may be detected at a downstream position of the drivetrain 62. Consequently, gear backlash and/or tolerance effects at the reduction gear unit 66 may only have a minor influence on the detection accuracy. For coupling the output shaft 68 and the location detection unit 80, the drive gear 70 of the output shaft 68 may be arranged to engage both the translatory movement element 54 and the location detection unit 80. To this end, the drive gear 70 may comprise a first toothed section 74 and a second toothed section 76. The first toothed section 74 may be arranged as a bevel gear section. The first toothed section 74 may engage the drivable gear 72. Generally, the drivable gear 72 and the first toothed section 74 may form a bevel gear set which may cover or span an angular offset between the output shaft 68 of the reduction gear unit 66 and the translatory movement element 54.

[0060] The drive gear 70 of the reduction gear unit 66 may further comprise a spur gearing arranged at the second toothed section 76. The second toothed section 76 may engage a corresponding detector gear wheel 82 arranged at a detector shaft 90 of the location detection unit, refer also to FIG. 7.

[0061] In some embodiments, the adjustment drive 58 may be arranged such that both the drivable gear 72 of the translatory movement element 54 and the detector gear wheel 82 of the detector shaft 90 may engage the same toothed section of the drive gear 70. This may involve an axial overlap between the drivable gear 72 and the detector gear wheel 82. Since the detector gear wheel 82 and the drivable gear 72 basically engage the same drive gear 70, an actual position of the movable comb portion 40 may be nearly directly detected. As with the embodiments shown in FIGS. 5, mainly remaining gearing tolerances or a gearing backlash that may occur at respective contact or engagement portions downstream of the reduction gear unit may influence the location detection accuracy.

[0062] As can be best seen from FIG. 5 and FIG. 7, the location detection unit 80 may comprise an encoder 84 that may comprise a detector shaft 90 that is rotatable with respect to a stationary detection portion of the encoder 84. The detector gear wheel 82 may be fixedly attached to the detector shaft 90. By way of example, the encoder 84 may comprise a Hall-sensor or a similar customary rotation sensor.

[0063] The encoder 84 may generate an output signal that is indicative of an actual position of the movable comb portion 40. The signal may be transferred to a control unit 86. The control unit 86 may process the respective signal. By way of example, the control unit 86 may be further coupled to the length adjustment control 22 illustrated in FIGS. 1, 3 and 4. The control unit 86 may be further coupled to the actuator 60 of the adjustment drive 58. Consequently, the actuator 60 may be operated on the basis of the positional information detected by the location detection unit 80. To this end, respective signal lines 92, 94 may be arranged between the encoder 84, the control unit 86 and the actuator 60, respectively.

[0064] FIG. 7 illustrates a further embodiment of an adjustment drive 58 for an adjustable spacing comb 26. More particularly, FIG. 7 further details an exemplary embodiment of a drivetrain 62 of the adjustment drive 58. The reduction gear unit 66 of the drivetrain 62 may arranged as a multi-stage reduction gear unit.

[0065] Generally, the actuator 60 may be arranged as a high-speed motor. Consequently, a considerably high gear ratio may be required to convert the high-speed rotational motion of the actuator 60 into a relatively low speed motion of the movable spacing comb which may involve a corresponding force or torque conversion.

[0066] As can be seen from FIG. 7, the output shaft or actuator shaft 64 of the actuator 60 may be coupled to a first gear stage 98, particularly a first reduction gear stage. The first gear stage 98 may be coupled to a second gear stage 100. The second gear stage 100 may be coupled to a third gear stage 102. The third gear stage 102 may be coupled to a fourth gear stage 104. The fourth gear stage 104 may be coupled to a fifth gear stage 106. The output shaft 68 of the reduction gear unit 66 may be coupled to the fifth gear stage 106. Each of the gear stages 98, 100, 102, 104, 106 may be arranged as a reduction gear set. It is worth mentioning in this regard that the embodiment of the reduction gear unit 60 shown in FIG. 7 is a rather exemplary embodiment. In other words, different configurations and different numbers of gear stages may be provided at the reduction gear unit 66.

[0067] Generally, the reduction gear unit 66 may be arranged as a multi-stage low reduction gear unit. Consequently, at each of the gear stages of the reduction gear unit 66, tolerances and/or gearing backlash may occur. Tolerances and gearing backlash may add up to a total gearing tolerance or backlash value. It is therefore beneficial to couple the location detection unit 80 to the output shaft 68. This may have the further advantage that at least some of the gear stages 98, 100, 102, 104, 106 or, at least, some of the gear wheels thereof may be arranged as low-cost components. Typically, low-cost gearing components are afflicted with significant gearing backlash and/or poor gearing accuracy. Since the location detection unit 80 is coupled to a downstream component of the reduction gear unit 66, these inaccuracies may have no influence on the precision and accuracy of the location detection.

[0068] 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.

[0069] 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.

[0070] Any reference signs in the claims should not be construed as limiting the scope.