Electric hair cutting device with independent drive members for shaving and hair trimming units

Abstract

The utility model provides an electric hair cutting device which is provided with a shaving unit and a hair trimming unit, and the shaving unit and the hair trimming unit can be interchangeably connected to a main shell with a motor. The hair trimming unit is also rotary and includes a driven member rotatable about a first axis of rotation. The main housing comprises: a separate wiper head drive member for each wiper head, which is rotatable by means of an electric motor; and a separate hair trimming unit drive member for the hair trimming unit, which is rotatable about the second axis of rotation by means of the electric motor. A driven member of the hair trimming unit has N primary engagement elements for engagement with corresponding N secondary engagement elements of a driving member of the hair trimming unit, where N is at least 2. The primary engagement element and the secondary engagement element are arranged in mutually rotationally symmetrical positions with respect to the first axis of rotation and the second axis of rotation, respectively.

Description

TECHNICAL FIELD

[0001] The utility model relates to an electric hair cutting device, including main casing, shaving unit and hair trimming unit, wherein shaving unit and hair trimming unit can be interchangeably coupled to the coupling side portion of main casing, and wherein:

[0002] - main casing contains motor and has first coupling member arranged at the coupling side portion;

[0003] - shaving unit includes at least two shaving heads, each shaving head has internal shaving head member and external shaving head member with hair inlet, the internal shaving head member can rotate relative to external shaving head member;

[0004] - shaving unit includes second coupling member, second coupling member is releasably coupled to first coupling member, and for each corresponding shaving head, shaving unit includes independent rotatable driven member, rotatable driven member is connected to internal shaving head member of corresponding shaving head;

[0005] - hair trimming unit includes external trimming unit member with hair inlet and internal trimming unit member rotatable relative to external trimming unit member;

[0006] - hair trimming unit includes third coupling member and driven member, third coupling member is releasably coupled to first coupling member, driven member can rotate around first rotation axis and is connected to internal trimming unit member;

[0007] - for each shaving head of shaving unit, main casing includes independent shaving head drive member, shaving head drive member can be rotated by means of motor and is arranged at the coupling side portion;

[0008] - main casing includes independent hair trimming unit drive member, hair trimming unit drive member can be rotated by means of motor around second rotation axis and is arranged at the coupling side portion;

[0009] - when shaving unit is coupled to main casing, shaving head drive member is respectively coupled to corresponding one of the driven members of shaving unit, thereby allowing motor to drive internal shaving head member of shaving unit; And

[0010] - when hair trimming unit is coupled to main casing, hair trimming unit drive member is coupled to driven member of hair trimming unit, thereby allowing motor to drive internal trimming unit member. BACKGROUND

[0011] CN220074756U discloses an electric hair cutting device as described in the "TECHNICAL FIELD" section. This known hair cutting device comprises a main housing, a shaving unit, a hair trimmer unit and a nose hair trimmer unit. The shaving unit has three rotary shaving heads. The hair trimmer unit has a fixed cutting member with a linear array of cutting teeth and a movable cutting member with a linear array of cutting teeth, the movable cutting member being arranged for linear reciprocating motion relative to the fixed cutting member. The nose hair trimmer unit is rotary. The shaving unit, the hair trimmer unit and the nose hair trimmer unit are interchangeably coupled to the main housing. The main housing comprises three main drive shafts configured and arranged to drive the three shaving heads of the shaving unit when the shaving unit is coupled to the main housing. The main housing further comprises an eccentric drive shaft arranged at the center between the three main drive shafts. The eccentric drive shaft comprises an eccentrically arranged drive member configured to drive the movable cutting member of the hair trimmer unit when the hair trimmer unit is coupled to the main housing and to drive the nose hair trimmer unit when the nose hair trimmer unit is coupled to the main housing. By the eccentrically arranged drive member, the rotation of the eccentric drive shaft is converted into the linear reciprocating motion of the movable cutting member of the hair trimmer unit. In order to enable the eccentrically arranged drive member to generate the rotary motion of the nose hair trimmer unit, the nose hair trimmer unit comprises a rotatable driven member which is couplable to the eccentrically arranged drive member. The rotatable driven member comprises an eccentrically arranged coupling cavity configured and arranged to receive the eccentrically arranged drive member of the eccentric drive shaft. A disadvantage of the eccentrically arranged coupling cavity of the rotatable driven member of the nose hair trimmer unit is that, when the driven member is driven by the eccentric drive shaft, the driven member will be subjected to an asymmetric load. Said asymmetric load will result in vibrations of the nose hair trimmer unit and excessive wear of the bearings of the driven member. SUMMARY

[0012] It is an object of the present utility model to provide an electric hair cutting device as described in the "TECHNICAL FIELD" section, which does not have the disadvantages of the known hair cutting devices as described in the foregoing. It is therefore an object of the present utility model to provide an electric hair cutting device comprising a main housing, a shaving unit having at least two rotary shaving heads and a rotary hair trimmer unit, wherein the shaving unit and the hair trimmer unit can be interchangeably coupled to the main housing, wherein the main housing comprises for each shaving head of the shaving unit an independent rotatable shaving head drive member and for the hair trimmer unit an independent rotatable hair trimmer unit drive member, and wherein the rotary hair trimmer unit can be driven by the hair trimmer unit drive member of the main housing without any significant asymmetric load occurring on the driven member of the hair trimmer unit.

[0013] To achieve the above object, the electric hair cutting device as described in the "Technical Field" section is characterized in that:

[0014] - the driven member of the hair trimming unit has N primary engagement elements configured and arranged to engage with corresponding N secondary engagement elements of the hair trimming unit drive member when the hair trimming unit is coupled to the main housing, wherein N is at least 2;

[0015] - the N primary engagement elements are arranged in mutually rotationally symmetrical positions with respect to the first rotation axis; and

[0016] - the N secondary engagement elements are arranged in mutually rotationally symmetrical positions with respect to the second rotation axis.

[0017] When the hair trimming unit is coupled to the main housing and the hair trimming unit drive member is rotated by means of the electric motor, the drive torque exerted by the electric motor will be transmitted to the rotatable inner trimming unit member of the hair trimming unit, via the N primary engagement elements of the hair trimming unit driven member of the main housing and the N secondary engagement elements of the hair trimming unit drive member that are mutually engaged. Since the N primary engagement elements are arranged in mutually rotationally symmetrical positions with respect to the first rotation axis of the driven member, and the N secondary engagement elements are arranged in mutually rotationally symmetrical positions with respect to the second rotation axis of the hair trimming unit drive member, said drive torque will be transmitted from the hair trimming unit drive member to the driven member in a rotationally symmetrical manner via the mutually engaged primary and secondary engagement elements. Therefore, the drive torque will be introduced into the hair trimming unit in a rotationally symmetrical manner, so that the drive torque does not cause any significant vibrations of the hair trimming unit or excessive wear of the bearings of the driven member of the hair trimming unit.

[0018] The hair trimming unit of the electric hair cutting device according to the present utility model can have any known type, including an outer trimming unit member having a hair inlet and an inner trimming unit member rotatable with respect to the outer trimming unit member, and including a rotatable driven member connected to the inner trimming unit member. In a preferred embodiment of the hair cutting device according to the present utility model, the hair trimming unit is a rotary type nose hair trimming unit.

[0019] According to the electric hair cutting device of the utility model, the shaving unit comprises at least two rotary shaving heads, each shaving head has an outer shaving head member with a hair inlet and an inner shaving head member rotatable relative to the outer shaving head member, and for each respective shaving head, the shaving unit comprises a separate rotatable driven member which is connected to the inner shaving head member of the respective shaving head. In one embodiment, the shaving unit comprises two rotary shaving heads. In this embodiment, the main housing comprises two shaving head drive members, and the hair trimming unit drive member can be arranged centrally between the two shaving head drive members. In particular, in this embodiment, the two shaving head drive members and the hair trimming unit drive member can be arranged in a mutually aligned configuration or a substantially aligned configuration.

[0020] In addition to the shaving unit and the hair trimming unit, the electric hair cutting device according to the utility model can also have an additional hair cutting unit and / or a skin treatment unit (such as a brushing unit) which can be coupled to the coupling side of the main housing instead of the shaving unit or the hair trimming unit. The additional hair cutting unit and / or the skin treatment unit can comprise a rotatable driven member which is configured and arranged to be driven by the hair trimming unit drive member of the main housing when the additional hair cutting unit or the skin treatment unit is coupled to the main housing. The additional hair cutting unit can be linearly reciprocating, comprising a movable cutting member which is arranged to linearly reciprocate relative to a fixed cutting member. In this case, the additional hair cutting unit can have a transmission system to convert the rotation of the driven member into the linear reciprocation of the movable cutting member. The skin treatment unit can be rotary or linearly reciprocating.

[0021] According to the utility model, the first coupling member of the main housing, the second coupling member of the shaving unit which is releasably coupled to the first coupling member, and the third coupling member of the hair trimming unit which is releasably coupled to the first coupling member can be of any suitable type known to those skilled in the art. For example, the first coupling member can be configured and arranged to cooperate with each of the second and third coupling members as a releasable snap connection, which enables the shaving unit and the hair trimming unit to be easily and conveniently coupled to and separated from the main housing.

[0022] In a preferred embodiment of the electric hair cutting device according to the utility model:

[0023] - the first coupling member comprises a locking member which is guided at the coupling side of the main housing displaceable in a displacement direction perpendicular to the second rotation axis from a coupling position to a separation position and vice versa;

[0024] - the locking member comprises at least one latching element;

[0025] - the second coupling member comprises at least one first latching groove configured and arranged to receive the at least one latching element in the coupling position of the locking member when the shaving unit is arranged at the coupling side and to release the at least one latching element in the decoupling position of the locking member, and

[0026] - the third coupling member comprises at least one second latching groove configured and arranged to receive the at least one latching element in the coupling position of the locking member when the trimming unit is arranged at the coupling side and to release the at least one latching element in the decoupling position of the locking member.

[0027] The interaction of the at least one latching element of the locking member of the first coupling member with the at least one first latching groove of the second coupling member and the at least one second latching groove of the third coupling member as implemented in the coupling position of the locking member provides a firm coupling of the main housing with the shaving unit and the trimming unit, respectively. In order to increase the firmness of the coupling between the first coupling member and the second and third coupling members, the locking member of the first coupling member can comprise a plurality of latching elements, the second coupling member can comprise an independent first latching groove for each latching element of the locking member, and the third coupling member can comprise an independent second latching groove for each latching element of the locking member. The first and second latching grooves can be arranged on the housing or frame of the shaving unit and the trimming unit, respectively, at a distance from each other. By displacing the locking member of the first coupling member from the coupling position to the decoupling position, the shaving unit and the trimming unit can be easily decoupled from the main housing, respectively.

[0028] In another embodiment of the electric hair cutting device according to the application:

[0029] - the locking member is plate-shaped and extends perpendicular to the second rotation axis;

[0030] - the plate-shaped locking member comprises an independent first opening for each respective shaving head drive member, the respective shaving head drive member extending through the first opening;

[0031] - the plate-shaped locking member comprises a second opening, the trimming unit drive member extending through the second opening.

[0032] The plate-shaped locking member leads to a firm and compact structure of the first coupling member and allows to provide a relatively large number of latching elements on the locking member at a distance from each other. The first and second openings in the plate-shaped locking member allow the plate-shaped locking member to extend over a large part of the coupling side of the main housing while still allowing the shaving head drive member and the hair trimming unit drive member to be arranged at the coupling side of the main housing.

[0033] In a further embodiment of the electric hair cutting device according to the utility model, the first coupling member comprises a plate-shaped locking member which is arranged at the coupling side of the main housing and which is provided with a first opening for the shaving head drive member and a second opening for the hair trimming unit drive member.

[0034] The plate-shaped locking member comprises two or more latching elements which are provided on a circumferential edge of the plate-shaped locking member.

[0035] The second coupling member comprises for each respective one of the latching elements a corresponding first latching groove which is provided on the inner side of the circumferential flange of the housing of the shaving unit.

[0036] The third coupling member comprises for each respective one of the latching elements a corresponding second latching groove which is provided on the inner side of the circumferential flange of the housing of the hair trimming unit.

[0037] Arranging two or more latching elements on a circumferential edge of the plate-shaped locking member and corresponding first and second latching grooves on the inner side of the circumferential flanges of the housings of the shaving unit and the hair trimming unit provides a highly stable and firm coupling between the main housing and the shaving unit and the hair trimming unit, respectively. Preferably, the latching elements are arranged on mutually opposite portions of the circumferential edge of the plate-shaped locking member. In embodiments in which the plate-shaped locking member is square or rectangular, preferably, the latching elements are provided on at least three of the four side edges of the plate-shaped locking member.

[0038] In a preferred embodiment of the electric hair cutting device according to the utility model, the locking member is biased by a spring force from the decoupled position to the coupled position and the locking member comprises a user operable knob which is arranged to protrude in the coupled position through an opening in the main housing and to be pressed into the opening against said spring force. During operation of the electric hair cutting device, the spring force reliably holds the locking member in the coupled position. By pressing the user operable knob into the opening in the main housing against the spring force, the user of the electric hair cutting device can easily decouple the shaving unit or the hair trimming unit from the main housing.

[0039] The above and other aspects of the utility model will be apparent from and elucidated with reference to the following detailed description of embodiments according to the utility model of the electric hair cutting device. BRIEF DESCRIPTION OF DRAWINGS

[0040] The application will be explained in more detail with reference to the drawings, in which identical or similar features are indicated by the same reference signs, and in which:

[0041] Fig. 1a shows an embodiment of an electric hair cutting device according to the application, wherein a shaving unit is coupled to the main housing;

[0042] Fig. 1b shows the electric hair cutting device of Fig. 1a, wherein a hair trimming unit is coupled to the main housing;

[0043] Figure 2 a schematic cross-section of the electric hair cutting device shown in the configuration of Fig. 1a is shown;

[0044] Figure 3 a schematic cross-section of the electric hair cutting device shown in the configuration of Fig. 1b is shown;

[0045] Figure 4 is a perspective view of the main housing of the electric hair cutting device of Fig. 1a and Fig. 1b;

[0046] Fig. 5a shows a cross-section of the electric hair cutting device along Figure 3 line V-V in Fig. 1a, wherein the coupling member of the hair trimming unit is coupled to the coupling member of the main housing; and

[0047] Fig. 5b shows the cross-section of Fig. 5a, wherein the coupling member of the hair trimming unit is uncoupled from the coupling member of the main housing. DETAILED DESCRIPTION

[0048] Figs. 1a and 1b show an embodiment of an electric hair cutting device 1 according to the application. The electric hair cutting device 1 comprises a main housing 3 configured to be held by a hand of a user. The main housing 3 houses an electric motor, a battery configured to power the electric motor, and electronic components configured to control the electric motor. These components of the electric hair cutting device 1 housed by the main housing 3 are well-known to the person skilled in the art and are therefore not shown in detail in Figs. 1a, 1b and will not be described in further detail.

[0049] The electric hair cutting device 1 comprises a shaving unit 5 and a hair trimming unit 7. The shaving unit 5 and the hair trimming unit 7 can be interchangeably coupled to a coupling side 9 of the main housing 3 by a user of the electric hair cutting device 1. Fig. 1a shows the electric hair cutting device 1, wherein the shaving unit 5 is coupled to the coupling side 9 of the main housing 3. Fig. 1b shows the electric hair cutting device 1, wherein the hair trimming unit 7 is coupled to the coupling side 9 of the main housing 3.

[0050] Figure 2A schematic cross-section of the electric hair cutting device 1 is shown, configured as shown in FIG. 1a, wherein the shaving unit 5 is coupled to the main housing 3. In the illustrated embodiment, the shaving unit 5 includes two rotary shaving heads 11a, 11b, which are well known to those skilled in the art and will therefore not be discussed in detail. Each shaving head 11a, 11b includes: an outer shaving head member 13a, 13b having an annular shaving region 15a, 15b with a hair inlet (not shown); and an inner shaving head member 17a, 17b, which, in the assembled state of the shaving unit 5, is covered by the outer shaving head member 13a, 13b and is rotatable relative to the outer shaving head member 13a, 13b about the central axes 19a, 19b of the shaving heads 11a, 11b.

[0051] like Figure 2 As shown, for each shaving head 11a, 11b of the shaving unit 5, the main housing 3 includes independent shaving head drive members 21a, 21b, which are rotatable by means of a motor 23 and are arranged at the connecting side 9 of the main housing 3. In the illustrated embodiment, each shaving head drive member 21a, 21b is connected to a corresponding driven gear in two driven gears 25a, 25b, each driven gear engaging a drive gear 27, which is centrally mounted to the motor shaft 29 of the motor 23 between the two driven gears 25a, 25b. For each shaving head 11a, 11b, the shaving unit 5 includes independent rotatable driven members 31a, 31b, which are connected to the internal shaving head members 17a, 17b of the corresponding shaving head 11a, 11b. Figure 2 As shown, when the shaving unit 5 is connected to the main housing 3, the shaving head drive members 21a and 21b of the main housing 3 are respectively connected to the corresponding driven members 31a and 31b of the shaving unit 5, thereby allowing the motor 23 to drive the internal shaving head members 17a and 17b of the shaving unit 5 to rotate relative to the external shaving head members 13a and 13b.

[0052] Figure 3 A schematic cross-section of the electric hair trimming device 1 is shown, configured as illustrated in FIG. 1b, wherein the hair trimming unit 7 is coupled to the main housing 3. The hair trimming unit 7 includes an outer trimming unit member 33 having a hair inlet 35 and an inner trimming unit member 37 rotatable relative to the outer trimming unit member 33. In the illustrated embodiment, the hair trimming unit 7 is a nose hair trimming unit, wherein the inner trimming unit member 37 is rotatable about the central axis 39 of the hair trimming unit 7. Such nose hair trimming units are well known to those skilled in the art and therefore will not be discussed in detail.

[0053] As Figure 3 shown in Fig. 2, the hair trimming unit 7 comprises a driven member 41 rotatable about a first rotation axis 43 and connected to the inner trimming unit member 37. In the shown embodiment, the first rotation axis 43 coincides with the central axis 39 of the hair trimming unit 7. The main housing 3 comprises a separate hair trimming unit drive member 45 rotatable about a second rotation axis 47 by means of the electric motor 23 and arranged at the coupling side 9 of the main housing 3. In the shown embodiment, the hair trimming unit drive member 45 is connected to an end portion of the motor shaft 29 of the electric motor 23, axially adjacent to the drive gear 27. As Figure 3 shown in Fig. 2, when the hair trimming unit 7 is coupled to the main housing 3, the hair trimming unit drive member 45 of the main housing 3 is coupled to the driven member 41 of the hair trimming unit 7 to allow the electric motor 23 to drive the inner trimming unit member 37 of the hair trimming unit 7 relative to the outer trimming unit member 33.

[0054] In the embodiment of the electric hair cutting device 1 previously described herein, the shaving unit 5 comprises two shaving heads 11a, 11b and the main housing 3 comprises two shaving head drive members 21a, 21b. In Figure 4 the perspective view of the main housing 3 of the electric hair cutting device 1 shown in Fig. 2, the arrangement of the two shaving head drive members 21a, 21b and the hair trimming unit drive member 45 at the coupling side 9 of the main housing 3 is shown in detail. As Figure 4 shown in Fig. 2, in this embodiment, the hair trimming unit drive member 45 is arranged centrally between the two shaving head drive members 21a, 21b. In particular, the two shaving head drive members 21a, 21b and the hair trimming unit drive member 45 are arranged in a near- aligned configuration. In alternative embodiments of the electric hair cutting device according to the present application, the shaving unit can have more than two shaving heads. For example, in an embodiment in which the shaving unit has three shaving heads arranged in a triangular configuration, the main housing can have three shaving head drive members arranged in a corresponding triangular configuration at the coupling side of the main housing, and the hair trimming unit drive member can be arranged in a central position between the three shaving head drive members.

[0055] In the cross-section of the electric hair cutting device 1 shown in Fig. 5a, the configuration of the electric hair cutting device 1 of Fig. 1 b is shown, i.e. in which the hair trimming unit 7 is coupled to the main housing 3. Fig. 5a shows the hair trimming unit drive member 45 of the main housing 3 in engagement with the driven member 41 of the hair trimming unit 7. The driven member 41 of the hair trimming unit 7 has three primary engagement elements 49 which are configured and arranged to be in engagement with three corresponding secondary engagement elements 51 of the hair trimming unit drive member 45 of the main housing 3 when the hair trimming unit 7 is coupled to the main housing 3, as shown in Fig. 5a. In Figure 4 The secondary engagement elements 51 of the hair trimming unit drive member 45 can also be seen in Fig. 5a. The primary engagement elements 49 are arranged in positions which are rotationally symmetrical with respect to the first rotational axis 43 of the driven member 41 of the hair trimming unit 7. The secondary engagement elements 51 are arranged in positions which are rotationally symmetrical with respect to the second rotational axis 47 of the hair trimming unit drive member 45 of the main housing 7. In the embodiment shown in Fig. 5a, the three primary engagement elements 49 are arranged in angular positions which mutually encompass an angle of 120° about the first rotational axis 43, and the three secondary engagement elements 51 are arranged in angular positions which mutually encompass an angle of 120° about the second rotational axis 47.

[0056] When the hair trimming unit drive member 45 is rotated by means of the electric motor 23, the drive torque (indicated by arrow T in Fig. 5a) generated by the electric motor 23 will be transmitted to the inner trimming unit member 37 of the hair trimming unit 7 via the mutually engaging secondary engagement elements 51 of the hair trimming unit drive member 45 of the main housing 3 and the primary engagement elements 49 of the driven member 41 of the hair trimming unit 7. Due to the rotationally symmetrical arrangement of the primary engagement elements 49 with respect to the first rotational axis 43 of the driven member 41 and the rotationally symmetrical arrangement of the secondary engagement elements 51 with respect to the second rotational axis 47 of the hair trimming unit drive member 45, the drive torque T will be transmitted from the hair trimming unit drive member 45 to the driven member 41 in a rotationally symmetrical manner via the mutually engaging primary and secondary engagement elements 49, 51. Thus, the drive torque T will be introduced into the hair trimming unit 7 in a rotationally symmetrical manner with respect to the first rotational axis 43 of the driven member 41 of the hair trimming unit 7, such that the drive torque T will not cause any significant vibrations of the hair trimming unit 7 or excessive wear of the bearings of the driven member 41 of the hair trimming unit 7.

[0057] It is noted that, according to the present utility model, at least two primary engagement elements are arranged on the driven member 41 of the hair trimming unit 7 in positions that are mutually rotationally symmetrical with respect to the first rotation axis 43 and at least two corresponding secondary engagement elements are arranged on the hair trimming unit drive member 45 of the main housing 3 in positions that are mutually rotationally symmetrical with respect to the second rotation axis 47. For example, in an embodiment with two primary engagement elements and two secondary engagement elements, the primary engagement elements can be arranged in angular positions that mutually encompass an angle of 180° around the first rotation axis 43 and the secondary engagement elements can be arranged in angular positions that mutually encompass an angle of 180° around the second rotation axis 47. In an alternative embodiment with four primary engagement elements and four secondary engagement elements, the primary engagement elements can be arranged in angular positions that mutually encompass an angle of 90° around the first rotation axis 43 and the secondary engagement elements can be arranged in angular positions that mutually encompass an angle of 90° around the second rotation axis 47.

[0058] In order to enable a user of the electric hair cutting device 1 to interchangeably couple the shaving unit 5 and the hair trimming unit 7 to the coupling side 9 of the main housing 3, the main housing 3 is provided with a first coupling member 61 arranged at the coupling side 9 of the main housing 3, the shaving unit 5 is provided with a second coupling member 63 that is releasably coupled to the shaving unit 5, and the hair trimming unit 7 has a third coupling member 65 that is releasably coupled to the first coupling member 61 of the main housing 3. The first coupling member of the main housing 3 is Figure 4 , Fig. 5a and Fig. 5b. The second and third coupling members of the shaving unit 5 and the hair trimming unit 7 are generally indicated in Fig. 5a and Fig. 5b by reference numerals 63 and 65. Preferred embodiments of the first, second and third coupling members 61, 63, 65 will be described in detail below with reference to Figure 4 , Fig. 5a and Fig. 5b. It will be clear to the skilled person that, for practical reasons, the second and third coupling members 63, 65 are preferably identical to allow the shaving unit 5 and the hair trimming unit 7 to each be coupled to the (identical) first coupling member 61 of the main housing 3. Therefore, in the following, preferred embodiments of the second and third coupling members 63, 65 will be described with respect to the third coupling member 65 of the hair trimming unit 7, as shown in Fig. 5a and Fig. 5b.

[0059] As Figure 4As shown in Figures 5a and 5b, the first connecting member 61 of the main housing 3 includes a locking member 71, which is guided at the connecting side 9 of the main housing 3 to be displaced in a displacement direction D perpendicular to the second rotation axis 47 of the hair trimming unit drive member 45 from a connected position relative to the third connecting member 65 of the hair trimming unit 7 to a separated position relative to the third connecting member 65. The locking member 71 can also be displaced from the separated position to the connected position in a displacement direction D' opposite to the displacement direction D. The connected position is shown in Figure 5a, and the separated position is shown in Figure 5b. Figure 4 As shown, in this embodiment, the locking member 71 is plate-shaped and extends perpendicular to the second rotation axis 47. For each of the shaving head drive members 21a, 21b, the plate-shaped locking member 71 includes a separate first opening 73a, 73b through which the shaving head drive members 21a, 21b extend. The plate-shaped locking member 71 also includes a second opening 75 through which the hair trimming unit drive member 45 extends. The connecting side 9 of the main housing 3 includes a pair of guide elements 77a, 77b that engage with a pair of guide grooves 79a, 79b provided in the plate-shaped locking member 71 for linearly guiding the plate-shaped locking member 71 along the displacement directions D, D'. The plate-shaped locking member 71 is in contact with the spring force F. S Under the action of the spring force F, the spring is biased from the separation position shown in Figure 5b to the connection position shown in Figure 5a. S A mechanical biasing spring is arranged below the plate-shaped locking member 71 and is not shown in the figures. The first coupling 61 of the main housing 3 also includes a user-operable knob 81, which is arranged to... Figure 4 The connection point shown in Figure 5a protrudes through the opening 83 in the main housing 3. The user can overcome the spring force F. S Pressing the knob 81 into the opening 83 causes the plate-shaped locking member 71 to move from the connected position shown in FIG. 5a to the disengaged position shown in FIG. 5b.

[0060] like Figure 4 As shown in Figures 5a and 5b, the plate-shaped locking member 71 of the first connecting member 61 in this embodiment includes four latching elements 85a, 85b, 85c, and 85d. The four latching elements 85a-85d are provided on the circumferential edge 87 of the plate-shaped locking member 71. As shown in Figures 5a and 5b, for each of the latching elements 85a-85d of the plate-shaped locking member 71, the third connecting member 65 of the hair trimming unit 7 includes corresponding latching recesses 91a, 91b, 91c, and 91d. The four latching recesses 91a-91d are provided on the inner side of the circumferential flange 93 of the housing 95 of the hair trimming unit 7. Figure 3The circumferential flange 93 and housing 95 of the hair trimming unit 7 are also shown. Latch recesses 91a-91d are configured and arranged such that when the hair trimming unit 7 is positioned on the connecting side 9 of the main housing 3, each latch recess receives and thereby holds the corresponding latch element 85a-85d of the plate-shaped locking member 71 in the connected position of the plate-shaped locking member 71 as shown in FIG. 5a, and releases the corresponding latch element 85a-85d in the disengaged position of the plate-shaped locking member 71 as shown in FIG. 5b. Therefore, when the user overcomes the spring force F... S When knob 81 is pressed into opening 83 of main housing 3, plate-shaped locking member 71 shifts from the connected position shown in FIG. 5a to the disengaged position shown in FIG. 5b, releasing latching elements 85a-85d from latching recesses 91a-91d, allowing the user to detach and remove hair trimming unit 7 from main housing 3. To connect hair trimming unit 7 to main housing 3, the user needs to position hair trimming unit 7 at the connecting side 9 of main housing 3 while overcoming spring force F. S Press the knob 81. This allows the latching elements 85a-85d to be brought into place relative to the latching recesses 91a-91d, which will receive them when the user subsequently releases the knob 81. Thus, the hair trimming unit 7 is reconnected to the main housing 3.

[0061] It will be apparent to those skilled in the art that the second connecting member 63 of the shaving unit 5 includes corresponding latching recesses for each latching element 85a-85d of the plate-shaped locking member 75, similar to the latching recesses 91a-91d of the third connecting member 65 of the hair trimming unit 7. The four latching recesses of the second connecting member 63 may be provided on the inner side of the circumferential flange 97 of the housing 99 of the shaving unit 5 in a manner similar to the latching recesses 91a-91d of the third connecting member 65. Figure 2 The image shows the circumferential flange 97 and housing 99 of the shaving unit 5.

[0062] As discussed in the "Summary of the Invention" section, the first coupling member of the main housing 3, the second coupling member of the shaving unit 5, and the third coupling member of the hair trimming unit 7 can be of any suitable type known to the skilled person. In embodiments where the first coupling member of the main housing 3 comprises a locking member which is guided at the coupling side 9 of the main housing 3 to be displaced in a manner similar to the plate-like locking member 71 of the first coupling member 61 described above, the locking member can comprise at least one latching element, the second coupling member of the shaving unit 5 can comprise at least one first latching groove which is configured and arranged to interact with the at least one latching element, and the third coupling member of the hair trimming unit 7 can comprise at least one second latching groove which is configured and arranged to interact with the at least one latching element, i.e. in the manner described above with respect to the latching grooves 91a-91d of the third coupling member 65. While a locking member having a single latching element (for interacting with a single latching groove on each of the second and third coupling members) can provide a secure coupling between the main housing 3 and the shaving unit 5 and the hair trimming unit 7, respectively, the locking member preferably has two or more latching elements arranged at a distance from each other to interact with a corresponding number of latching grooves on the second and third coupling members. The locking member of the first coupling member can not be plate-like, but can have any suitable support structure which is configured to support one or more latching elements and which is guided in a displaceable manner at the coupling side 9 of the main housing 3. A plate-like locking member, such as the plate-like locking member 71 of the first coupling member 61 described above, has the advantage of having a simple and robust structure and being able to support a relatively large number of latching elements. By providing the latching elements 85a-85d on the circumferential edge 87 of the plate-like locking member 71, the latching elements 85a-85d can be arranged at a relatively large distance from each other, which will increase the security and stability of the coupling between the main housing 3 and the shaving unit 5 and the hair trimming unit 7, respectively.

[0063] Variations of the disclosed embodiments can become apparent to those of ordinary skill in the art upon reading the foregoing description, and it is intended to include all such variations. 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. The mere fact that measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope of the claims.

Claims

1. An electric hair cutting device comprising a main housing (3), a shaving unit (5) and a hair trimming unit (7), wherein the shaving unit and the hair trimming unit are interchangeably couplable to a coupling side (9) of the main housing, and wherein: the main housing houses an electric motor (23) and has a first coupling member (61) arranged at the coupling side; the shaving unit comprises at least two shaving heads (11a, 11b), each shaving head having an inner shaving head member (17a, 17b) and an outer shaving head member (13a, 13b) with a hair inlet, the inner shaving head member being rotatable relative to the outer shaving head member; the shaving unit comprises a second coupling member (63) that is releasably coupled to the first coupling member, and for each respective shaving head, the shaving unit comprises an independent rotatable driven member (31a, 31b) connected to the inner shaving head member of the respective shaving head; the hair trimming unit comprises an inner trimming unit member (37) and an outer trimming unit member (33) with a hair inlet (35), the inner trimming unit member (37) being rotatable relative to the outer trimming unit member; the hair trimming unit comprises a third coupling member (65) that is releasably coupled to the first coupling member, and a driven member (41) rotatable about a first rotation axis (43) and connected to the inner trimming unit member; for each shaving head of the shaving unit, the main housing comprises an independent shaving head drive member (21a, 21b) rotatable by the electric motor and arranged at the coupling side; the main housing comprises an independent hair trimming unit drive member (45) rotatable about a second rotation axis (47) by means of the electric motor and arranged at the coupling side; when the shaving unit is coupled to the main housing, the shaving head drive members are respectively coupled to respective ones of the driven members of the shaving unit, thereby allowing the electric motor to drive the inner shaving head members of the shaving unit; and when the hair trimming unit is coupled to the main housing, the hair trimming unit drive member is coupled to the driven member of the hair trimming unit, thereby allowing the electric motor to drive the inner trimming unit member; characterized in that: the driven member (41) of the hair trimming unit (7) has N primary engagement elements (49) configured and arranged to engage with corresponding N secondary engagement elements (51) of the hair trimming unit drive member (45) when the hair trimming unit is coupled to the main housing (3), wherein N is at least 2. ​ The N primary engagement elements are arranged in positions that are rotationally symmetrical with respect to the first axis of rotation (43); and The N secondary engagement elements are arranged in positions that are rotationally symmetrical with respect to the second axis of rotation (47).

2. The electric hair cutting device according to claim 1, characterized in that The hair trimming unit (7) is a nose hair trimming unit.

3. The electric hair cutting device according to claim 1 or 2, characterized in that: The first coupling member (61) comprises a locking member (71) guided at the coupling side (9) of the main housing (3) so as to be displaceable in a displacement direction (D, D') perpendicular to the second axis of rotation (47) from a coupled position to a decoupled position and vice versa; The locking member comprises at least one latching element (85a, 85b, 85c, 85d); The second coupling member (63) comprises at least one first latching groove configured and arranged to receive the at least one latching element in the coupled position of the locking member when the shaving unit (5) is arranged at the coupling side and to release the at least one latching element in the decoupled position of the locking member; and The third coupling member (65) comprises at least one second latching groove (91a, 91b, 91c, 91d) configured and arranged to receive the at least one latching element in the coupled position of the locking member when the hair trimming unit (7) is arranged at the coupling side and to release the at least one latching element in the decoupled position of the locking member.

4. The electric hair cutting device according to claim 3, characterized in that: The locking member (71) is plate-shaped and extends perpendicular to the second axis of rotation (47); The locking member comprises a second opening (75) through which the hair trimming unit drive member (45) extends.

5. The electric hair cutting device according to claim 4, characterized in that: The locking member (71) comprises two or more latching elements (85a, 85b, 85c, 85d) provided on a circumferential edge (87) of the locking member; The second coupling member (63) comprises for each respective one of the latching elements a corresponding first latching groove provided on an inner side of a circumferential flange (97) of a housing (99) of the shaving unit (5); and The second coupling member (63) comprises for each respective one of the latching elements a corresponding first latching groove provided on an inner side of a circumferential flange (97) of a housing (99) of the shaving unit (5); For each respective one of the latching elements, the third coupling member (65) comprises a corresponding second latching recess (91a, 91b, 91c, 91d) provided on the inner side of a circumferential flange (93) of a housing (95) of the hair trimming unit (7).

6. The electric hair cutting device as claimed in claim 3, characterized in that: The locking member (71) is biased by a spring force (F S ) from the uncoupled position to the coupled position; and The locking member comprises a user operable knob (81) arranged to protrude through an opening (83) in the main housing (3) in the coupled position and to be depressible into the opening against the spring force.

Images