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

Abstract

The invention provides an electric hair cutting device (1) having a shaving unit (5) and a hair trimming unit (7), which can be interchangeably coupled to a main housing having an electric motor (23). The shaving unit comprises at least two rotary shaving heads (11a, 11b), and for each shaving head, there is an independent rotatable driven member (31a, 31b). The hair trimming unit is also rotary, such as a vibrissa trimming unit, and further comprises a driven member (41) rotatable about a first axis of rotation (43). The main housing comprises: a separate wiper head drive member (21a, 21b) for each wiper head, which is rotatable by means of an electric motor; and a separate hair trimming unit drive member (45) for the hair trimming unit, which is rotatable about a second axis of rotation (47) by means of the electric motor. The driven member of the hair trimming unit has N primary engagement elements (49) for engagement with corresponding N secondary engagement elements (51) of the 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 present invention relates to an electric hair cutting device, comprising a main housing, a shaving unit and a hair trimming unit, wherein the shaving unit and the hair trimming unit can be interchangeably coupled to a coupling side portion of the main housing, and wherein:

[0002] - the main housing accommodates the electric motor and has a first coupling member arranged at the coupling side;

[0003] - the shaving unit comprises at least two shaving heads, each shaving head having an outer shaving head member with a hair inlet and an inner shaving head member, the inner shaving head member being rotatable relative to the outer shaving head member;

[0004] the shaving unit comprises a second coupling member which is releasably coupled to the first coupling member and, for each respective shaving head, the shaving unit comprises an independent rotatable driven member which is connected to the inner shaving head member of the respective shaving head;

[0005] - the hair trimming unit comprises an outer trimming unit component having a hair inlet and an inner trimming unit component rotatable relative to the outer trimming unit component;

[0006] - the hair trimming unit comprises a third coupling member, which is releasably coupled to the first coupling member, and a driven member, which is rotatable about a first rotation axis and is connected to the inner trimming unit member;

[0007] - for each shaving head of the shaving unit, the main housing comprises an independent shaving head drive member, which can be rotated by means of an electric motor and is arranged at the coupling side;

[0008] - the main housing comprises a separate hair trimming unit drive member, which is rotatable about the second rotation axis by means of an electric motor and is arranged at the coupling side;

[0009] - when the shaving unit is coupled to the main housing, the shaving head drive members are each coupled to a respective one of the driven members of the shaving unit, thereby allowing the electric motor to drive the internal shaving head members of the shaving unit; and

[0010] - 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 internal trimming unit components. Background Art

[0011] CN220074756U discloses an electric hair cutting device as described in the "technical field" section. This known hair cutting device includes a main housing, a shaving unit, a hair trimmer unit and a nose hair trimming 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, and the movable cutting member is arranged to reciprocate linearly relative to the fixed cutting member. The nose hair trimming unit is rotary. The shaving unit, the hair trimmer unit and the nose hair trimming unit are interchangeably connected to the main housing. The main housing includes three main transmission shafts, which are configured and arranged to drive the three shaving heads of the shaving unit when the shaving unit is connected to the main housing. The main housing also includes an eccentric transmission shaft, which is arranged at the center between the three main transmission shafts. The eccentric drive shaft comprises an eccentrically arranged drive member, which is configured to drive a movable cutting member of the hair trimmer unit when the hair trimmer unit is connected to the main housing and to drive the nose hair trimming unit when the nose hair trimming unit is connected to the main housing. By means of the eccentrically arranged drive member, the rotation of the eccentric drive shaft is converted into a 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 rotational motion of the nose hair trimming unit, the nose hair trimming unit comprises a rotatable driven member, which can be coupled to the eccentrically arranged drive member. The rotatable driven member comprises an eccentrically arranged coupling cavity, which is configured and arranged to receive the eccentrically arranged drive member of the eccentrically arranged drive shaft. The disadvantage of the eccentrically arranged coupling cavity of the rotatable driven member of the nose hair trimming unit is that when the driven member is driven by the eccentric drive shaft, the driven member will be subjected to an asymmetric load. The asymmetric load will cause vibration of the nose hair trimming unit and excessive wear of the bearings of the driven member. Summary of the invention

[0012] The object of the present invention is to provide an electric hair cutting device as described in the section "Technical field" which does not have the disadvantages of the known hair cutting devices as described above. Therefore, the object of the present invention is to provide an electric hair cutting device comprising a main housing, a shaving unit having at least two rotatable shaving heads and a rotary hair trimming unit, wherein the shaving unit and the hair trimming unit can be interchangeably connected to the main housing, wherein for each shaving head of the shaving unit the main housing comprises an independent rotatable shaving head drive member and for the hair trimming unit the main housing comprises an independent rotatable hair trimming unit drive member, and wherein the rotary hair trimming unit can be driven by the hair trimming unit drive member of the main housing without any significant asymmetric load occurring on the driven member of the hair trimming unit.

[0013] In order to achieve the above-mentioned 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 rotationally symmetrical positions with respect to the first rotation axis; and

[0016] The N secondary engagement elements are arranged in rotationally symmetrical positions with respect to one another 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 driving torque applied by the electric motor will be transmitted to the rotatable internal trimming unit member of the hair trimming unit via the mutually engaged N primary engagement elements of the driven member of the hair trimming unit of the main housing and the N secondary engagement elements of the hair trimming unit drive member. 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, the driving torque will be transmitted from the hair trimming unit drive member to the driven member via the mutually engaged primary engagement elements and secondary engagement elements in a rotationally symmetrical manner. Therefore, the driving torque will be introduced into the hair trimming unit in a rotationally symmetrical manner, so that the driving torque does not cause any significant vibration 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 invention may be of any known type, comprising an outer trimming unit member having a hair inlet and an inner trimming unit member rotatable relative to the outer trimming unit member, and comprising a rotatable driven member connected to the inner trimming unit member. In a preferred embodiment of the hair cutting device according to the present invention, the hair trimming unit is a nose hair trimming unit of the rotary type.

[0019] The shaving unit of the electric hair cutting device according to the present invention comprises at least two rotary shaving heads, each shaving head having an external shaving head component with a hair inlet and an internal shaving head component rotatable relative to the external shaving head component, and for each corresponding shaving head, the shaving unit comprises an independent rotatable driven component, which is connected to the internal shaving head component of the corresponding shaving head. In one embodiment, the shaving unit comprises two rotary shaving heads. In this embodiment, the main housing comprises two shaving head drive components, and the hair trimming unit drive component can be arranged centrally between the two shaving head drive components. In particular, in this embodiment, the two shaving head drive components and the hair trimming unit drive component 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 present invention can also have an additional hair cutting unit and / or a skin treatment unit (such as a brushing unit), which can be connected to the connection 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 include a rotatable driven member, which is configured and arranged to be driven by the hair trimming unit driving member of the main housing when the additional hair cutting unit or the skin treatment unit is connected to the main housing. The additional hair cutting unit can be a linear reciprocating type, including a movable cutting member, which is arranged to reciprocate linearly relative to the 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 reciprocating motion of the movable cutting member. The skin treatment unit can be a rotary type or a linear reciprocating type.

[0021] According to the present invention, the first coupling member of the main housing, the second coupling member of the shaving unit releasably coupled to the first coupling member, and the third coupling member of the hair trimming unit releasably coupled to the first coupling member may be of any suitable type known to those skilled in the art. For example, the first coupling member may be configured and arranged to cooperate with each of the second and third coupling members to be 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 present invention:

[0023] - the first coupling member comprises a locking member which is guided at the coupling side of the main housing so as to be displaceable in a displacement direction perpendicular to the second rotation axis from a coupling position to a decoupling 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 recess configured and arranged to receive at least one latching element in a coupled position of the locking member and to release at least one latching element in a decoupled position of the locking member when the shaving unit is arranged at the coupling side; and

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

[0027] As achieved in the coupling position of the locking members, the interaction of at least one latching element of the locking member of the first coupling member with at least one first latching groove of the second coupling member and at least one second latching groove of the third coupling member provides a secure coupling of the main housing to the shaving unit and the hair trimming unit, respectively. In order to increase the secureness of the coupling between the first coupling member and the second and third coupling members, the locking member of the first coupling member may include a plurality of latching elements, the second coupling member may include an independent first latching groove for each latching element of the locking member, and the third coupling member may include an independent second latching groove for each latching element of the locking member. The first and second latching grooves may be arranged at a distance from each other on the housing or frame of the shaving unit and the hair trimming unit, respectively. By shifting the locking member of the first coupling member from the coupling position to the separation position, the shaving unit and the hair trimming unit, respectively, may be easily separated from the main housing.

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

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

[0030] - for each respective one of the shaving head drive members, the plate-like locking member comprises a separate first opening through which the respective shaving head drive member extends;

[0031] - The plate-like locking member comprises a second opening through which the hair trimming unit drive member extends.

[0032] The plate-like locking member results in a strong and compact structure of the first coupling member and allows providing a relatively large number of latching elements at a distance from each other on the locking member. The first and second openings in the plate-like locking member allow the plate-like 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 yet another embodiment of the electric hair cutting device according to the present invention:

[0034] - the plate-like locking member comprises two or more latching elements, which are provided on a circumferential edge of the plate-like locking member;

[0035] - for each respective one of the latching elements, the second coupling member comprises a corresponding first latching groove provided on the inner side of the circumferential flange of the housing of the shaving unit; and

[0036] - For each respective one of the latching elements, the third coupling member comprises 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 the circumferential edge of the plate-like locking member and arranging corresponding first and second latching grooves on the inner side of the circumferential flange of the housing of the shaving unit and the hair trimming unit provides a highly stable and secure connection between the main housing and the shaving unit and the hair trimming unit, respectively. Preferably, the latching elements are arranged on mutually opposite parts of the circumferential edge of the plate-like locking member. In embodiments in which the plate-like locking member is square or rectangular, preferably, the latching elements are provided on at least three of the four side edges of the plate-like locking member.

[0038] In a preferred embodiment of the electric hair cutting device according to the present invention, the locking member is biased from the disconnected position to the coupled position by a spring force, and the locking member comprises a user operable knob, which is arranged to protrude through an opening in the main housing in the coupled position and can be pressed into the opening against the 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, a user of the electric hair cutting device can easily separate the shaving unit or the hair trimming unit from the main housing.

[0039] The above and other aspects of the invention will be apparent from and elucidated from the following detailed description of an embodiment of an electric hair cutting device according to the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The present invention will be described in more detail with reference to the accompanying drawings, in which the same or similar features are indicated by the same reference numerals, and in which:

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

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

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

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

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

[0046] Figure 5a shows the Figure 3 a cross-section of the electric hair cutting device along line VV in which 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 separated from the coupling member of the main housing. DETAILED DESCRIPTION

[0048] Fig. 1a and Fig. 1b show an embodiment of an electric hair cutting device 1 according to the present invention. The electric hair cutting device 1 comprises a main housing 3, which is configured to be held by a user's hand. The main housing 3 contains: a motor, a battery configured to power the motor, and an electronic component configured to control the motor. These components of the electric hair cutting device 1 contained by the main housing 3 are well known to those skilled in the art, and therefore these components are not shown in detail in Fig. 1a, Fig. 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. A user of the electric hair cutting device 1 can interchangeably connect the shaving unit 5 and the hair trimming unit 7 to a connecting side 9 of the main housing 3. Fig. 1a shows an electric hair cutting device 1 in which the shaving unit 5 is connected to a connecting side 9 of the main housing 3. Fig. 1b shows an electric hair cutting device 1 in which the hair trimming unit 7 is connected to a connecting side 9 of the main housing 3.

[0050] Figure 2A schematic cross section of an electric hair cutting device 1 is shown, which is configured as shown in FIG. 1a, i.e., wherein a shaving unit 5 is coupled to a main housing 3. In the embodiment shown, the shaving unit 5 comprises two rotating shaving heads 11a, 11b, which is well known to the skilled person and will not be discussed in detail. Each shaving head 11a, 11b comprises an outer shaving head member 13a, 13b having an annular shaving area 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 can rotate relative to the outer shaving head member 13a, 13b about a central axis 19a, 19b of the shaving head 11a, 11b.

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

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

[0053] like Figure 3 As shown in , the hair trimming unit 7 includes a driven member 41, which is rotatable around a first rotation axis 43 and is connected to the internal trimming unit member 37. In the illustrated embodiment, the first rotation axis 43 coincides with the central axis 39 of the hair trimming unit 7. The main housing 3 includes an independent hair trimming unit drive member 45, which is rotatable around a second rotation axis 47 by means of the motor 23 and is arranged at the coupling side 9 of the main housing 3. In the illustrated embodiment, the hair trimming unit drive member 45 is connected to the end portion of the motor shaft 29 of the motor 23, axially adjacent to the drive gear 27. As shown in Figure 3 As shown in the figure, when the hair trimming unit 7 is connected to the main shell 3, the hair trimming unit driving member 45 of the main shell 3 is connected to the driven member 41 of the hair trimming unit 7 to allow the electric motor 23 to drive the internal trimming unit member 37 of the hair trimming unit 7 to rotate relative to the external trimming unit member 33.

[0054] In the embodiments of the electric hair cutting device 1 described hereinbefore, the shaving unit 5 comprises two shaving heads 11a, 11b, and the main housing 3 comprises two shaving head drive members 21a, 21b. Figure 4 In the perspective view of the main housing 3 of the electric hair cutting device 1 shown in FIG, 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. Figure 4 As shown in, 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 configuration close to being aligned with each other. In an alternative embodiment of the electric hair cutting device according to the present invention, 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. 1b is shown, i.e., wherein the hair trimming unit 7 is coupled to the main housing 3. FIG. 5a shows that the hair trimming unit drive member 45 of the main housing 3 is engaged 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 engage 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 . Figure 4 5a, the three primary engagement elements 49 are arranged in angular positions that surround each other by 120° around the first rotation axis 43 and the three secondary engagement elements 51 are arranged in angular positions that surround each other by 120° around the second rotation axis 47.

[0056] When the hair trimming unit drive member 45 is rotated by means of the motor 23, the driving torque (indicated by arrow T in FIG. 5 a) generated by the motor 23 will be transmitted to the internal trimming unit member 37 of the hair trimming unit 7 via the mutually engaged 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 element 49 with respect to the first rotation axis 43 of the driven member 41 and the rotationally symmetrical arrangement of the secondary engagement element 51 with respect to the second rotation axis 47 of the hair trimming unit drive member 45, the driving torque T will be transmitted from the hair trimming unit drive member 45 to the driven member 41 via the mutually engaged primary engagement elements 49 and the secondary engagement elements 51 in a rotationally symmetrical manner. Therefore, the drive torque T will be introduced into the hair trimming unit 7 in a rotationally symmetrical manner relative to the first rotation axis 43 of the driven member 41 of the hair trimming unit 7, so that the drive torque T will not cause any significant vibration 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 should be noted that according to the present invention, at least two primary engagement elements are arranged on and in the driven member 41 of the hair trimming unit 7 in positions that are 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 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 may be arranged in angular positions that mutually surround 180° around the first rotation axis 43, and the secondary engagement elements may be arranged in angular positions that mutually surround 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 may be arranged in angular positions that mutually surround 90° around the first rotation axis 43, and the secondary engagement elements may be arranged in angular positions that mutually surround 90° around the second rotation axis 47.

[0058] In order to enable the user of the electric hair cutting device 1 to interchangeably connect the shaving unit 5 and the hair trimming unit 7 to the connecting side 9 of the main housing 3, the main housing 3 is provided with a first connecting member 61 arranged at the connecting side 9 of the main housing 3, the shaving unit 5 is provided with a second connecting member 63 which is releasably connected to the shaving unit 5, and the hair trimming unit 7 has a third connecting member 65 which is releasably connected to the first connecting member 61 of the main housing 3. The first connecting member 61 of the main housing 3 is provided at Figure 4 5a and 5b are generally indicated by reference numeral 61. The second and third coupling members of the shaving unit 5 and the hair trimming unit 7 are generally indicated by reference numerals 63 and 65 in FIGS. 5a and 5b. Figure 4 5a and 5b describe in detail preferred embodiments of the first, second and third coupling members 61, 63, 65. 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 be each coupled to the (same) 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 Figures 5a and 5b.

[0059] like Figure 45a and 5b, the first coupling member 61 of the main housing 3 includes a locking member 71, which is guided at the coupling side portion 9 of the main housing 3 so as to be displaceable from a coupling position relative to the third coupling member 65 of the hair trimming unit 7 to a separation position relative to the third coupling member 65 in a displacement direction D perpendicular to the second rotation axis 47 of the hair trimming unit driving member 45. The locking member 71 can also be displaced from the separation position to the coupling position in a displacement direction D' opposite to the displacement direction D. The coupling position is shown in FIG5a, and the separation position is shown in FIG5b. As shown in FIG5a , the coupling position is shown in FIG5b . Figure 4 As shown in , in this embodiment, the locking member 71 is plate-shaped and extends perpendicularly to the second rotation axis 47. For each of the shaving head drive members 21a, 21b, the plate-shaped locking member 71 includes an independent 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, which 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 under the spring force F S The spring force F is provided to bias the spring from the disconnected position shown in FIG. 5b to the connected position shown in FIG. 5a. S The mechanical bias spring is arranged below the plate-like locking member 71 and is not shown in the drawings. The first coupling member 61 of the main housing 3 also includes a user-operable knob 81, which is arranged to be rotated at Figure 4 5a and protrudes through the opening 83 in the main housing 3. The user can overcome the spring force F S The knob 81 is pressed into the opening 83 , whereby the plate-like locking member 71 is displaced from the coupled position shown in FIG. 5 a to the decoupled position shown in FIG. 5 b .

[0060] like Figure 4 5a and 5b, the plate-shaped locking member 71 of the first coupling member 61 comprises four latching elements 85a, 85b, 85c and 85d in this embodiment. The four latching elements 85a-85d are provided on the circumferential edge 87 of the plate-shaped locking member 71. As shown in Figs. 5a and 5b, for each of the latching elements 85a-85d of the plate-shaped locking member 71, the third coupling member 65 of the hair trimming unit 7 comprises a corresponding latching groove 91a, 91b, 91c, 91d. The four latching grooves 91a-91d are provided on the inner side of the circumferential flange 93 of the housing 95 of the hair trimming unit 7. Figure 35a, and releases the corresponding latching element 85a-85d in the disengaged position of the plate-like locking member 71 as shown in FIG. 5b. Thus, when the user overcomes the spring force F S When the knob 81 is pressed into the opening 83 of the main housing 3, the plate-shaped locking member 71 is shifted from the coupling position shown in FIG. 5a to the separation position shown in FIG. 5b, so that the latch elements 85a-85d are released from the latch grooves 91a-91d, and the user can separate and remove the hair trimming unit 7 from the main housing 3. In order to couple the hair trimming unit 7 to the main housing 3, the user needs to arrange the hair trimming unit 7 at the coupling side 9 of the main housing 3 while overcoming the spring force F S The knob 81 is pressed. Thereby, the latching elements 85a-85d can be brought into position relative to the latching grooves 91a-91d, wherein they can be received by the latching grooves 91a-91d when the user subsequently releases the knob 81. Thereby, the hair trimming unit 7 is coupled to the main housing 3 again.

[0061] It is obvious to a person skilled in the art that the second coupling member 63 of the shaving unit 5 comprises, for each latching element 85a-85d of the plate-like locking member 71, a corresponding latching groove similar to the latching grooves 91a-91d of the third coupling member 65 of the hair trimming unit 7. The four latching grooves of the second coupling 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 grooves 91a-91d of the third coupling member 65. Figure 2 The circumferential flange 97 and the housing 99 of the shaving unit 5 are shown in FIG.

[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 may be of any suitable type known to those skilled in the art. In embodiments where the first coupling member of the main housing 3 includes a locking member, the locking member 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 may include at least one latching element, the second coupling member of the shaving unit 5 may include at least one first latching groove, the first latching groove being configured and arranged to interact with the at least one latching element, and the third coupling member of the hair trimming unit 7 may include at least one second latching groove, the second latching groove being 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. Although 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 connection 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 may not be plate-shaped, but may have any suitable support structure that is configured to support one or more latching elements and is guided in a displaceable manner at the coupling side 9 of the main housing 3. A plate-shaped locking member (such as the plate-shaped locking member 71 of the first coupling member 61 described above) has the advantage of having a simple and secure 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-shaped locking member 71, the latching elements 85a-85d can be arranged at a relatively large distance from each other, which will increase the secureness and stability of the connection between the main housing 3 and the shaving unit 5 and the hair trimming unit 7, respectively.

[0063] Variations to the disclosed embodiments may be understood and implemented by those skilled in the art in practicing the principles and techniques herein by studying the drawings, the disclosure, and the appended claims. 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 certain 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 a claim should not be construed as limiting the scope of the claim.

Claims

1. An electric hair cutting device (1), comprising a main housing (3), a shaving unit (5) and a hair trimming unit (7), wherein the shaving unit and the hair trimming unit can be interchangeably coupled to a coupling side (9) of the main housing, and wherein: The main housing accommodates the 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 component (17a, 17b) and an outer shaving head component (13a, 13b) with a hair inlet, the inner shaving head component being rotatable relative to the outer shaving head component; The shaving unit comprises a second coupling member (63) which is releasably coupled to the first coupling member and, for each respective shaving head, comprises an independent rotatable driven member (31a, 31b) which is connected to the inner shaving head member of the respective shaving head; The hair trimming unit comprises an inner trimming unit component (37) and an outer trimming unit component (33) having a hair inlet (35), wherein the inner trimming unit component (37) is rotatable relative to the outer trimming unit component; The hair trimming unit comprises a third coupling member (65) which is releasably coupled to the first coupling member and a driven member (41) which is rotatable about a first rotation axis (43) and is connected to the inner trimming unit member; For each shaving head of the shaving unit, the main housing comprises an independent shaving head driving member (21a, 21b), which can be rotated by the motor and is arranged at the coupling side; The main housing comprises an independent hair trimming unit drive member (45) which can be rotated about a second rotation axis (47) by means of the electric motor and is arranged at the coupling side; when the shaving unit is coupled to the main housing, the shaving head drive members are respectively coupled to corresponding ones of the driven members of the shaving unit, thereby allowing the motor to drive the internal shaving head members of the shaving unit; as well as 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 motor to drive the internal trimming unit member; Features: 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 rotationally symmetrical positions relative to the first rotation axis (43); and The N secondary engagement elements are arranged in rotationally symmetrical positions with respect to the second rotation axis (47).

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

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

4. The electric hair cutting device (1) according to claim 3, wherein: The locking member (71) is plate-shaped and extends perpendicularly to the second rotation axis (47); the plate-like locking member comprising, for each respective one of the shaving head drive members (21a, 21b), a separate first opening (73a, 73b) through which the respective shaving head drive member extends; The plate-like locking member comprises a second opening (75) through which the hair trimming unit drive member (45) extends.

5. The electric hair cutting device (1) according to claim 4, wherein: The plate-like locking member (71) comprises two or more latching elements (85a, 85b, 85c, 85d), the two or more latching elements being provided on a peripheral edge (87) of the plate-like locking member; the second coupling member (63) comprising, for each respective one of the latching elements, a corresponding first latching recess provided on the inner side of a circumferential flange (97) of a housing (99) of the shaving unit (5); as well as For each respective one of the latching elements, the third coupling member (65) comprises a corresponding second latching groove (91a, 91b, 91c, 91d), which is provided on the inner side of a circumferential flange (93) of the housing (95) of the hair trimming unit (7).

6. The electric hair cutting device (1) according to any one of claims 3 to 5, wherein: The locking member (71) is provided with a spring force (F S ) is biased from said disengaged position to said coupled position; as well as The locking member comprises a user operable knob (81) which is arranged to protrude through an opening (83) in the main housing (3) in the coupled position and can be pressed into the opening against the spring force.

Images