Shaving unit with lubricating arrangement

Abstract

A shaving unit (16) is disclosed comprising a housing (12), a guard (20) stationary relative to the housing (12), a cutting edge (22) arranged at a distance from the guard (20) and stationary relative to the housing, a hair-entry opening bounded by the guard and the cutting edge, and a drum (24) arranged within the housing, the drum (24) being configured to be driven rotatingly about a longitudinal axis thereof. A plurality of counter cutting edges (28) is arranged on the drum (24), wherein the counter cutting edges (28) cooperate with the cutting edge (22) during rotation of the drum (24) about the longitudinal axis (26) for shearing or cutting hairs when the shaving unit (16) is moved over a skin (30). The shaving unit (16) further comprises a lubricating arrangement (36) with a liquid reservoir (38) filled with a lubricant and with a feed mechanism (41) for supplying the lubricant from the liquid reservoir (38) to at least one of the counter cutting edges (28) for providing a lubricating film (42) thereto. The feed mechanism (41) comprises a lubricating element (39) arranged adjacent to the drum (24) in a position such as to engage the at least one counter cutting edge (28) during rotation of the drum (24) about the longitudinal axis (26).

Claims

1. A shaving unit coupled to a housing, comprising: a guard stationary relative to the housing; a cutting edge arranged at a distance from the guard and stationary relative to the housing; a hair-entry opening bound by the guard and the cutting edge; a drum arranged within the housing, the drum being configured to be driven rotatingly about a longitudinal axis thereof; at least one counter cutting edge arranged on the drum for cooperating with the cutting edge during rotation of the drum about the longitudinal axis for shearing or cutting hairs entering the hair-entry opening; and a lubricating arrangement comprising: a liquid reservoir configured for receiving a lubricant, and a feed mechanism including a lubricating element arranged adjacent to the drum in a position such as to engage the at least one counter cutting edge during rotation of the drum about the longitudinal axis for providing a lubricating film to the at least one counter cutting edge.

2. The shaving unit of claim 1, wherein the position of the lubricating element is such that, during rotation of the drum about the longitudinal axis, the lubricating element engages the at least one counter cutting edge after the counter cutting edge passing the cutting edge and prior to the counter cutting edge contacting the skin after said passing and before next passing the cutting edge.

3. The shaving unit of claim 1, wherein the liquid reservoir comprises a pad configured for being soaked with the lubricant.

4. The shaving unit of claim 1, wherein the lubricating element comprises a wick being in contact with the liquid reservoir and configured for being soaked with the lubricant from the liquid reservoir.

5. The shaving unit of claim 4, wherein the wick extends from the liquid reservoir towards a path followed by the at least one counter cutting edge during rotation of the drum about the longitudinal axis.

6. The shaving unit of claim 1, wherein the lubricating arrangement comprises a bias spring being arranged for biasing the lubricating element towards the drum.

7. The shaving unit of claim 1, wherein the feed mechanism comprises means for regulating a supply of the lubricant depending on a degree of friction between the lubricating element and the at least one counter cutting edge during rotation of the drum.

8. The shaving unit of claim 4, wherein the wick is arranged at an acute angle relative to a tangential direction of the drum at the position where the wick engages the counter cutting edge during rotation of the drum.

9. The shaving unit of claim 4, wherein the lubricating arrangement further comprises a wick supporting spring for biasing the wick towards the drum.

10. The shaving unit of claim 1, wherein the lubricating arrangement is configured as a replaceable part that can be removed from the shaving unit and replaced by a new lubricating arrangement by a user of the shaving unit.

11. The shaving unit of claim 1, wherein the lubricating arrangement is part of a replaceable cartridge, optionally a replaceable cartridge comprising the guard or the cutting edge.

12. The shaving unit of claim 1, wherein the drum comprises a plurality of counter cutting edges each extending parallel to the longitudinal axis of the drum.

13. The shaving unit of claim 1, wherein the drum comprises a plurality of counter cutting edges arranged on free-standing catenary or cantilevered structures protruding from the drum.

14. The shaving unit of claim 1, wherein the at least one counter cutting edge is configured as a ridge arranged on the drum.

15. A shaving appliance comprising the shaving unit and the housing according to claim 1, the housing configured to be held by a hand.

16. The shaving unit of claim 1, wherein the cutting edge has a radius of curvature of 30 micrometers or less.

17. The shaving unit of claim 1, wherein the drum comprises a plurality of counter cutting edges each extending spirally around the longitudinal axis of the drum.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter. In the following drawings

(2) FIG. 1 shows a simplified side view of a shaving appliance including a shaving unit according to the invention, wherein for ease of presentation the drum with the counter cutting edges is shown without the outer housing usually concealing the two axial ends thereof;

(3) FIG. 2 shows the shaving unit with the guard, cap and drum as moved over a skin;

(4) FIG. 3 shows the shaving unit of FIG. 2 including a lubricating arrangement according to the invention for lubricating at least one of the counter cutting edges, not shown in FIGS. 1 and 2;

(5) FIG. 4 shows a slightly modified embodiment of the shaving unit of FIG. 3;

(6) FIG. 5 shows an enlarged representation of the part of the wick providing a lubricating film on one of the counter cutting edges;

(7) FIG. 6 shows another modification of the shaving unit according to FIG. 4;

(8) FIG. 7 shows several phases of the wick resting against an end of one counter cutting edge, with a) showing a normal action, b) showing enhanced friction, and c) showing enhanced liquid supply resulting from higher friction;

(9) FIG. 8 shows a drum with spirally extending counter cutting edges configured as ridges on the drum; and

(10) FIG. 9 shows a perspective representation of the drum 24 including four catenary or cantilevered structures 29 that are wound spirally around the outer surface of the drum 24. The counter cutting edges 28 represent the outer surfaces of the catenary or cantilever structures 29.

DETAILED DESCRIPTION OF THE INVENTION

(11) In FIG. 1 a shaving appliance is shown configured as a razor and depicted in total with reference numeral 10.

(12) The shaving appliance 10 comprises a housing 12 extending generally in a longitudinal way. The shaving appliance 10 may be held with one hand at a rear part 13 thereof.

(13) According to FIG. 1 the shaving unit 16 basically comprises a guard 20 and a cutting edge 22 stationary within the housing, and a drum 24 carrying four counter cutting edges 28 arranged thereon.

(14) At the lower front end of the housing 12 the guard 20 is arranged that is configured for supporting the cutting edge 22 and to guide the shaving unit 16 over the skin. The cutting edge 22 and the guard define a hair-entry opening 23. The drum 24 is arranged within the cavity bound by the guard 20 and the cutting edge 22 and can be driven rotatingly about a longitudinal axis 26 thereof. At the lower middle part of the housing 12 the cap 18 is arranged.

(15) From the surface of the drum 24 there extend four free-standing wing-like catenary or cantilever structures 29 each having an outer end configured as a counter cutting edge 28. These counter cutting edges 28 cooperate with the cutting edge 22 provided at the end of the cap 18 facing the drum 24 to effect hair cutting or shearing.

(16) In FIG. 1 a drive merely denoted with reference numeral 14 is shown that is configured for driving the drum 24 rotatingly. Further features, such as controls, etc. are not shown for ease of representation.

(17) The overall arrangement of the shaving unit 16 according to FIG. 2 consists of the cutting edge 22 that is moved over the skin 30 with the rotating drum 24 equipped with the counter cutting edges 28 to shear or cut the hairs. To support the cutting edge 22 and guide the shaving unit 16 over the skin, the guard 20 is provided, and the cutting edge 22 is extended into a cap area. As one of the counter cutting edges 28 moves across the cutting edge 22, a cutting line 44 is defined at the crossing line.

(18) The guard 20 may be a closed or open, teethed guard. To improve the skin-flow, a low friction area may be provided on the cap 20, and a relatively higher friction may be provided on the guard 18.

(19) During shaving the shaving unit 16 is moved over the skin 30 into the direction of arrow 32, while the drum 24 with the counter cutting edges 28 rotates in the direction of arrow 34. Up to this point the shaving unit 16 is of conventional design.

(20) FIG. 9 shows a perspective representation of the drum 24 including four catenary or cantilevered structures 29 that are would spirally around the outer surface of the drum 24. The counter cutting edges 28 represent the outer surfaces of the catenary or cantilever structures 29.

(21) According to the invention there is provided a lubricating arrangement designated in total with 36 (see FIG. 3, not shown in FIGS. 1 and 2 for ease of representation).

(22) During shaving the shaving unit 16 is moved over the skin 30 by a user. The speed of shaving varies greatly between individuals and can be anywhere between 3 and 300 mm/second. The drum 24 is actively driven. For the cutting function the respective counter cutting edges 28 must be operated at a speed that is larger than the shaving speed. The counter cutting edges 28 and any supporting surface area of the rotating drum 24 thus are generally in sliding contact at a speed greater than 300 mm/second. With a typical shaving speed of 100 mm/second, the relative speed of the counter cutting edges 28 to the skin 30 is in excess of 200 mm/second and typically in 500 mm/second range.

(23) To achieve a close shave, the skin 30 must in close contact and at some pressure with the counter cutting edge 28 in the area immediately in front of the cutting edge 22. Typically this area is not smaller than 0.5 mm, ideally much wider.

(24) According to FIG. 3 the lubricating arrangement 36 comprises a liquid reservoir 38 within which an effusing pad 39 may be arranged. In addition, the effusing pad 39 may be spring-biased into the direction of the drum 24 by a spring element 40. Further there is a feed mechanism designated in total with 41 for supplying lubricant from the liquid reservoir 38 to at least one of the counter cutting edges 28. In its simplest form, the feed mechanism 41 may only comprise the spring element 40 pressing the effusing pad 39 into the direction of the counter cutting edges 28.

(25) The cutting edge 22 has a radius of curvature enabling hair cutting in co-operation with the counter cutting edge 28. Thus it must be “sharp”. In particular the radius of curvature of the cutting edge 28 is equal to or smaller than 30 micrometers, more preferably equal to or smaller than 20 micrometers, and most preferably equal to or smaller than 15 micrometers, or in the single digit range of micrometers. The counter cutting edge 28 is the outer skin contacting surface of the drum 24 cooperating with the cutting edge 22 (see FIG. 9) and having a radius of curvature adapted to some extend to the radius of curvature of the cutting edge 22.

(26) According to FIGS. 3 and 4 a lubricating film depicted with 42 is provided by the effusing pad 39 onto one of the counter cutting edges 28 being in contact with the effusing pad 39, before the cutting edge 22 is reached during rotation of the drum 24.

(27) Thus, the lubricating film 42 is applied, before the respective counter cutting edge 28 contacts the skin 30. As a consequence, the lubricating film 42 is immediately applied before the cutting line 44 is reached. Thus, there is a direct lubricating, before the cutting process begins.

(28) The effusing pad 39 for instance may be a stiff felt pad that is infused with a lubricant comprising polyethylene glycol and held within the liquid reservoir 39.

(29) The lubricating arrangement 36 is preferably configured as a consumer replaceable part, a consumable.

(30) It may be configured as a cartridge 21 together with the guard 20, thereby allowing an easy replacement. As mentioned before, the cartridge 21 may be replaceable together with a different part, such as the cutting edge 22 or the drum 24.

(31) In FIG. 4 a slight modification of the shaving unit is shown and depicted in total with reference numeral 16a. Apart from that the same reference numerals are used for corresponding parts.

(32) The lubricant arrangement 36 according to FIG. 4 comprises a wick 46 extending from the liquid reservoir 38. In this way the exposed area can be reduced when compared to the overall dimensions of the liquid reservoir 38. The pad 39 according to FIG. 3 extends over the entire width of the drum 24 (typically in the order of 32 mm). The angle of exposure is limited to a minimum, when the pad 39 according to FIG. 3 is replaced by a wick 46, drawing the lubricant out of the reservoir 38, as shown in FIG. 4.

(33) In this case the pad 39 may be dispensed with or may still be present within the liquid reservoir 38, if desired.

(34) As shown in more detail in FIG. 5 the end of the wick 46 leads to the formation of the lubricating film 42 on the respective surface of the counter cutting edge 28 in contact therewith, while the counter cutting edge 28 moves into a tangential direction 35.

(35) To regulate the amount of lubricant transferred onto the counter cutting edges 28, the friction of the lubricating pad 39 or of the wick 46 may be used to regulate the pressure of the wick 46 onto the rotating counter cutting edge 28 in contact with the wick 46. This can be done in several ways. A simple method is to angle the wick 46 resiliently against the direction of movement, namely the tangential direction 35 of the counter cutting edges 28.

(36) This situation is shown in FIG. 6, wherein the shaving unit is depicted in total with 16b.

(37) In FIG. 6 the tangential direction of a counter cutting edge 28 being in contact with the wick 46 is depicted with line 35. Between the wick 46 and the tangential direction 35 there is included an acute angle α. The wick 46 is spring biased by a wick supporting spring 46 against the surface of the counter cutting edge 28 in contact therewith.

(38) When arranged against the direction of rotation 34 as shown in FIG. 6, the wick 46 resting against the drum 24 or at least over part of its length against one of the counter cutting edges 28 of the rotating drum 24, functions as a belt brake. The friction of the rotating drum 24 or counter cutting edge 28 against the wick 46 deforms the wick 46 and presses it against the rotating part. This will initiate and/or stimulate the flow and transfer of lubricant.

(39) This situation is shown in FIG. 7.

(40) FIG. 7a) shows the initial normal condition. According to FIG. 7b) the wick 46 is deformed at its outer end resting against the counter cutting edge 28. By the deformation the pressure on the wick 46 is increased. This leads to an enhancement of liquid flow, leading to an enhancement of the lubricating film 42 shown in FIG. 7c).

(41) Thus, the wick 46 resiliently pressed against the counter cutting edge 28 being at least partially in contact therewith leads to a self-regulation of the lubricant feed for supplying a continuous lubricating film 42 prior to contacting the cutting line 44.

(42) Similarly, the friction of the drum 24 against a resilient or movable part (not shown) can be used to regulate or open the flow of lubricant. Also other known methods of controlling lubricant flow can be incorporated. Known are e.g. methods to require skin-contact pressure to engage the fluid or other shaving-related secondary controls.

(43) Many variations of the basic concept described above with respect to the lubricating arrangement 36 exist to which the invention can be applied. This includes also a purely manual control, such as by a push-button or similar control. For example, the counter cutting edges 28 of the drum 24 can be free-standing catenary or cantilever structures as described above or can be configured as ridges 50 on a solid drum configured as a cylinder as shown in FIG. 8.

(44) The counter cutting edges 28 may also be edges of apertures of varying shapes in a hollow tube. Similarly the guard 20 can have a multitude of shapes, as can have the cutting edge area and the adjacent cap area.

(45) While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

(46) In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. A single element or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

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