Realization of a defined exposure distance setting in the hair cutting unit of a rotary electric shaver.

Abstract

In a hair-cutting unit for a rotary electric shaver of the type comprising an external cutting member 10, an internal cutting member and a support member 30, the exposure distance by which the skin-contacting surface of the shaving track of the external cutting member 10 projects relative to the upper surface of the support member 30 is adjustable. For this purpose, an adjustment system is provided, which comprises, inter alia, at least one adjustment set of guide grooves and driven elements 42 engaging in said guide grooves, as well as an initial position setting system configured to enable synchronization of the exposure distance settings between a number of hair-cutting units, during which an initial position of the driven elements 42 in the guide grooves, defined by the stops of said guide grooves, is achieved and maintained.

Claims

1. A hair cutting unit for a rotary electric shaver, An external cutting member equipped with a shaving track having a hair entry point, An internal cutting member is covered by the external cutting member and is rotatable around the central axis of the hair cutting unit relative to the external cutting member, A support member that surrounds and supports the aforementioned external cutting member, An adjustment system for adjusting the exposure distance at which the skin contact surface of the shaving track protrudes from the upper surface of the support member, comprising an adjustment actuator and an adjustment transmission system, wherein the adjustment actuator is capable of adjusting the exposure distance via the mutual relative rotation of the external cutting member and the support member around the central axis, and the adjustment transmission system has a conversion mechanism that converts the mutual relative rotation of the external cutting member and the support member around the central axis into mutual relative axial motion of the external cutting member and the support member in an axial direction parallel to the central axis, The conversion mechanism has at least one set of guide grooves and a driven element that engages with the guide grooves, The guide groove is inclined with respect to a virtual plane perpendicular to the central axis and is provided on either i) the inner surface of the support member surrounding the external cutting member and ii) the outer circumferential surface of the external cutting member. The driven element is provided on the other of i) the inner surface of the support member and ii) the outer circumferential surface of the outer cutting member. The guide groove has a stop device that defines the initial position of the driven element in the guide groove, corresponding to one of the minimum and maximum values ​​of the exposure distance. In the first operating state, the adjustment actuator is capable of operating to achieve mutual relative rotation of the external cutting member and the support member in a first rotational direction around the central axis, thereby obtaining a displacement of the driven element toward the initial position in the guide groove; while in the second operating state, it is capable of operating to achieve mutual relative rotation of the external cutting member and the support member in a second rotational direction opposite to the first rotational direction around the central axis. The adjustment transmission system further includes an initial position setting system that, when the driven element reaches the initial position in the guide groove, stops the mutual relative axial movement of the external cutting member and the support member during the continuous operation of the adjustment actuator in the first operating state, thereby maintaining one of the minimum and maximum values ​​of the exposure distance. Hair cutting unit.

2. The hair cutting unit according to claim 1, wherein the external cutting member is rotatable around the central axis relative to the support member.

3. The adjustment transmission system has a driven gear attached to the external cutting member, while the adjustment actuator has a drive gear that engages with the driven gear. The first and second operating states of the adjustment actuator are accompanied by the corresponding opposite rotation of the drive gear in the first and second directions. The hair cutting unit according to claim 2.

4. The hair cutting unit according to claim 3, wherein the initial position setting system prevents the adjustment actuator from acting on the external cutting member during the continuous operation of the adjustment actuator in the first operating state when the driven element reaches the initial position in the guide groove.

5. The initial position setting system has, for each set of the guide groove and the driven element, a gap in the driven gear where there are no teeth of the gear, The gap is positioned such that, when the driven element is in the initial position in the guide groove, the gap faces the drive gear and prevents the drive gear from driving the driven gear, with respect to one of the guide groove and the driven element provided on the outer circumferential surface of the external cutting member. The hair cutting unit according to claim 4.

6. The hair cutting unit according to claim 5, wherein the stopping device in the guide groove of one of the at least one set of guide grooves and driven elements has an elastic element that biases the driven element out of the initial position in the guide groove when the driven element is in the initial position in the guide groove.

7. The guide groove is provided on the carrier portion of the support member, The initial position setting system, when the driven element reaches the initial position in the guide groove, allows the carrier portion to rotate together with the external cutting member around the central axis with respect to the main portion of the support member during the continuous operation of the adjustment actuator in the first operating state. The hair cutting unit according to claim 2.

8. The hair cutting unit according to claim 7, wherein the initial position setting system has a holding device that holds the carrier portion in a stationary position on the main portion of the support member when the driven element is in a position other than the initial position in the guide groove, and allows the carrier portion to rotate around the central axis relative to the main portion of the support member when the adjustment actuator is operating in the first operating state and the driven element reaches the initial position in the guide groove.

9. The hair cutting unit according to claim 8, wherein the holding device has a friction structure on the main parts of the carrier portion and / or the support member that are in contact with each other and extend tangentially around the central axis.

10. The hair cutting unit according to any one of claims 1 to 9, wherein the guide groove has an opening that allows the driven element to be removed from the guide groove by manually moving the external cutting member and the support member relative to each other in the axial direction.

11. The hair cutting unit according to any one of claims 1 to 9, wherein the conversion mechanism has three sets of guide grooves and driven elements, and these three sets are arranged at 120° angular intervals around the central axis.

12. A shaving assembly having at least two hair cutting units according to any one of claims 1 to 9, and a base unit for supporting the at least two hair cutting units.

13. The shaving assembly according to claim 12, wherein in each of the hair cutting units, the adjustment actuator is operated in the first operating state during the initial operating stage of the shaving assembly so that in each of the hair cutting units, the driven element in the at least one set of guide grooves and driven element reaches the initial position in the guide groove.

14. The shaving assembly according to claim 12, wherein the adjustment system of the hair cutting units has a common adjustment actuator, and the common adjustment actuator has a common drive gear located in the center between the hair cutting units.

15. A rotary electric shaver comprising a main body and a shaving assembly as described in claim 12, wherein the base unit of the shaving assembly is connected to the main body.

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