IES20050781A2

IES20050781A2 - Cutter blade assembly and rotary dry shaver for variable height of cut

Info

Publication number: IES20050781A2
Authority: IE
Inventors: P J Walls
Original assignee: P J Walls
Priority date: 2005-11-24
Filing date: 2005-11-24
Publication date: 2007-05-30

Abstract

The present invention relates to a cutter blade assembly for a rotary shaver comprising a cutter blade and a cooperating shear blade arrangement. The assembly is characterised in that the cutter blade is a rotary cutter blade and the cutter blade has an overlying cooperating shear blade (61). The spacing between a skin ûengaging surface (65) of the shear blade and the opposite face thereof for co-operation with the associated cutter blade varies about the circumference of the shear blade such that the spacing between a portion (69) of the skin engaging surface of the shear blade and the opposite face therof is increased as compared with the spacing required to achieve a ôclose shaveö. The invention also relates to a rotary dry shaver comprising a housing (77); and a plurality of the cutter blade assemblies (72) mounted within the housing. The cutter blade assemblies are arranged such that the portion (74) of each assembly which has an increased spacing between the skin-engaging surface of the shear blade and opposite face thereof is oriented centrally of the shaver such that said portions are arranged adjacent one another to provide a central raised shaving platform (75). <Figure 4>

Description

Field of the Invention This invention relates to cutter blade assemblies for rotary dry shavers having a cutter blade and a cooperating shear blade arrangement. The invention also relates to rotary dry shavers of the type having a rotary cutter member or blade underlying an external shear member provided with apertures for entry of the hairs to be cut.

Background to the Invention The history of shaving to date has been the search for the ever-closer shave.

However, certain skin and hair types develop "shaving bumps" or pseudofolliculitis barbae (PFB) in certain areas of the beard when a close shave is effected. This can occur where obliquely exiting hairs are cut tangentially too close to the skin surface causing them to re-enter into the skin where they may occasion inflammation. In shaving close, certain skin and hair types thus experience or develop inflammation due to re-entry into the skin of the closely shaved hairs.

Description of the Prior Art United States Patent No. 4,003,390 discloses the use of apertured guides or spacers between the razor head and the skin in order to cut or trim hairs at a predetermined distance from the skin.

United States Patent No. 5,867,908 describes a rotary razor external cutting member having apertures of varying width in order to cut longer and shorter hairs more effectively and with less irritation, but ultimately achieving a "close" shave.

International Published Patent Application No. WO 98/35794 describes different shaving fields provided on an external cutting member, oriented in a fashion so that the longer hairs are cut first, or pre-shaved, by the outside fields before being properly close ΙΈ 050 781 European Patent No. 1 231 034 granted to the current applicant describes a rotary razor giving a variable height of cut, a specific embodiment of such envisaged using interchangeable shaving heads of different thicknesses and, in a further embodiment, a double shaving head containing an outer displaceable "dummy" shield so as to achieve a variable height of cut. In contrast, the present invention relates to a thickening of the shear blade itself in order to firmly grasp and hold the hairs rigid at the skin surface in order to cut the hairs long at their point of exit.

Object of the Invention It is a general object of the invention to provide a cutter blade assembly and rotary dry shaver directed to overcoming the inflammation problems discussed hereinabove. It is another object of the invention to provide a cutter blade assembly directed to achieving a variable height of cut by varying the thickness of the shear blade about its circumference so as to achieve selectively a short or a long hair shave by using the same shear blade. It is a further object of the invention to provide a rotary dry shaver which allows for a close shave in certain areas and a "longer" shave in other areas.

Summary of the Invention According to a first aspect of the present invention, there is provided a cutter blade assembly comprising a cutter blade and a co-operating shear blade arrangement in which provision is made for the spacing between a skin-engaging surface of the cutter blade assembly and regions of the shear blade arrangement which cooperate with the cutter blade to be increased as compared with the spacing required to achieve a "close shave", characterised in that the cutter blade is a rotary cutter blade, the or each cutter blade having a co-operating overlying shear blade and the spacing between a skin engaging surface of the shear blade and the opposite face thereof for co-operation with the rotary cutter blade (i.e. the cutter blade surface or side of the shear blade) varies about the circumference of the shear blade, such that the spacing between a portion of the skin engaging surface of the shear blade and the opposite face thereof is increased as compared with the spacing required to achieve a "close shave".

The cutter blade assembly of the present invention is therefore directed to achieving a variable height of cut by varying the thickness of the shear blade about its IE 0 50 78 1 circumference or periphery so as to achieve selectively a short or a long hair shave using the same shear blade. Each cutter blade assembly is therefore capable of providing a long or short shave.

Preferably, the spacing between the skin engaging surface of the shear blade and the opposite face thereof is increased as compared with the spacing required to achieve a "close shave" over one third to one eighth of the circumference of the shear blade.

More preferably, the spacing between the skin-engaging surface of the shear blade and the opposite face thereof is increased as compared with the spacing required to achieve a "close shave" over about one quarter of the circumference of the shear blade.

The cutter blade assembly may comprise at least two transition regions wherein the spacing between the skin-engaging surface of the shear blade and the opposite face thereof is increasing or decreasing, respectively. Starting from a portion of the assembly where the spacing between the skin-engaging surface of the shear blade and the opposite face thereof is at a minimum, the spacing increases at the transition regions. Conversely, starting from a portion of the assembly where the spacing between the skinengaging surface of the shear blade and the opposite face thereof is at a maximum, the spacing decreases at the transition regions.

According to one embodiment of the cutter blade assembly, the spacing between the skin-engaging surface of the shear blade and the opposite face thereof varies gradually about the circumference of the shear blade, such that said transition regions are relatively long. In this embodiment, the spacing between the skin-engaging surface of the shear blade and the opposite face thereof may increase continuously and uniformly from a minimum spacing to a maximum spacing, and may decrease continuously and uniformly from the maximum spacing to the minimum spacing. Thus the shear blade may be tapered about its entire circumference, such that the transition regions extend over substantially the whole of the circumference of the shear blade, each transition region extending over substantially one half of the circumference of the shear blade.

H gSi « 050761 An advantage of this arrangement is that the gradual tapering of the shear blade allows the hairs in non-problem areas of the beard to be shaven progressively closer and closer to the skin surface.

According to an alternative embodiment of the cutter blade assembly, the spacing between the skin-engaging surface of the shear blade and the opposite face thereof changes abruptly at two positions on the circumference of the shear blade, such that the transition regions are relatively short. Working around the circumference of the shear blade, the spacing between the skin-engaging surface and the opposite face thereof thus increases sharply at a first point on the circumference and decreases sharply at a second point on the circumference of the shear blade.

An advantage of this arrangement is that the transition between the "close shave" and "long shave" regions of the cutter blade assembly is easily felt by the user and is immediately clear to him. The user may thus easily apply the desired height of shave to each area of the skin surface to be shaved.

Preferably, the shear blade comprises a plurality of radially-oriented hair entry openings extending from the skin-engaging surface of the shear blade to the opposite face thereof.

Ideally, the shear blade comprises a plurality of substantially radially-oriented tines or struts, and a hair entry opening is provided between each pair of adjacent tines. The thickness of the tines varies about the circumference of the shear blade such that the spacing between a portion of the skin engaging surface of the shear blade and the opposite face thereof is increased as compared with the spacing required to achieve a "close shave". Each transition region may comprise between two and five tines or struts.

According to a second aspect of the invention, there is provided a rotary dry shaver comprising a housing, and a plurality of cutter blade assemblies as described above mounted within the housing, wherein the cutter blade assemblies are arranged such that the portion of each assembly which has an increased spacing between the skin-engaging surface of the shear blade and the opposite face thereof is oriented centrally of the 050781 shaver such that said portions are arranged adjacent one another to provide a central raised shaving plane or platform.

The rotary dry shaver of the present invention may therefore be used to prevent or protect against inflammation caused by pseudofolliculitis barbae by using the central raised shaving plane (or platform) to purposely cut the hair long at a sufficient distance from the skin surface so as to prevent any possible re-entry into the skin of the close cut hairs.

According to a preferred embodiment, the rotary dry shaver comprises three cutter blade assemblies mounted within the housing in a trefoil arrangement.

Preferably, the cutter blade assemblies are moveably mounted within the housing such that the central portion of each shear blade is downwardly displaceable to allow outwardly oriented portions of the shear blade to engage the skin to achieve a "close shave".

It is a particular object of the present invention to provide a dry shaver in which the depth of cut is variable, so that hair to be cut may be left at a variable length over certain areas of the skin as required, in order, inter alia, to avoid the development of a shaving rash due to re-entry into the skin of too-short tangentially cut hairs exiting the skin at an acute angle. An advantage of this arrangement is that a single shaver may be used to perform both long and short shaves, without requiring replacement of parts or changing of settings by the user. The switch from long shave to short shave is simply effected by increasing the pressure with which the shaver is held against the skin surface.

Ideally, the shear blade of each cutter blade assembly is resiliently upwardly biased, such that each shear blade is resiliently downwardly displaceable within the shaver.

In one embodiment, each cutter blade assembly is moveably mounted within a frame, and each frame is moveably mounted within the housing. Each frame may be resiliently upwardly biased, such that each frame is resiliently downwardly displaceable within the shaver. A central portion of each frame may be greater in height than outwardly ^ 050 781 oriented portions of the frame, such that the central portion of each cutter blade assembly is tilted upwards relative to outwardly oriented portions of the cutter blade assembly. One or more stops may be provided within the housing to limit the downward displacement of the shear blades and/or the frames.

Brief Description of the Drawings Figure 1 is a diagrammatic representation of a portion of human skin, in the region of the surface of the skin, in section, showing inner and outer skin layers and hair growth, and representing also a particular condition in which an individual’s body hair is subject to growth in a manner more horizontal than vertical; Figure 2 is a pictorial view of a rotary shaver of known construction, to which the present invention may be applied; Figure 3 is a side sectional view of a shear blade of conventional construction for use in the shaver of Figure 2; Figure 4 is an isometric view of a shear blade of the cutter blade assembly of the present invention; Figure 5 is a side cross-sectional view of the shear blade of Figure 1; Figure 6 is a front elevation view of a rotary shaver head in which three cutter blade assemblies according to the present invention are mounted to provide a central raised shaving platform; Figure 7 is a diagrammatic view in section of the rotary shaver head of Figure 3 in which the central raised shaving platform is in its raised condition; and Figure 8 is a side cross-sectional view of the cutter blade assemblies of Figure 4, in which the central raised shaving platform has been depressed.

Detailed Description of the Drawings Figure lisa representation in sectional view of a portion of the surface of the skin of an individual. As shown in Figure 1, the outer layer 1 of the skin is underlaid by an inner layer 2. Hairs 3 and 3a grow outwardly through the skin from respective root regions 4 and 4a and emerge through the outer layer 1 of the skin. In the normal way, as indicated by hair 3, a hair should emerge from the skin outer layer 1 and extend outwardly above the skin surface substantially at right angles to the skin surface. Depending on the region of the skin surface in question, certain hairs such as that designated by reference IE 0 50 79f 3a in Figure 1 may have a hair shaft which is oriented horizontally and almost parallel with the skin surface. When such a hair emerges from the skin surface, as indicated at reference 3b, it does so obliquely and in a highly tangential manner.

If an individual suffering from such tangential hair growth wishes to effect a close shave and cuts the hair relatively close to the skin outer surface, a condition known as pseudofolliculitis barbae may develop. This occurs when the hairs are cut too short such that the sharp, cut edge of the hair becomes engaged by the homy outer layer 1 of the skin and is re-directed downwards into the dermis. The hair thus burrows back beneath the surface of the skin, as indicated at reference 3c, rather than emerging from the skin and growing externally in the normal manner. If growth then continues with the hair 3 running into and under the skin, the inevitable result is ingrowth of the hair accompanied by inflammation of the skin.

It is therefore preferable to prevent the development of any such inflammation and the present invention addresses this problem. The concept underlying the avoidance of such skin conditions is to cut the hair slightly above the surface of the skin in areas of the body surface where the possibility of such ingrowing conditions arising is likely to be greatest. The advantages of its being possible to cut hair in accordance with the principles of the present invention are not however limited only to skin conditions such as that illustrated with reference to Figure 1, but the invention is also applicable to all skin circumstances where shaving bumps or other skin eruptions or imperfections militate against an excessively close shave. The invention provides the user of a dry shaver with the ability to selectively cut body hair either tightly or to a greater length, depending on the region of the skin in question, i.e. the area currently being shaved.

Referring now to Figure 2 of the drawings, there is shown a rotary dry shaver of generally conventional construction. The shaver 41 has a number of cutter blade assemblies 42, typically three as shown in the drawing, or alternatively two assemblies 42, in each case located at the cutting end face 43 of the shaver body 44.

In such constructions, each cutter blade assembly 42 has an external or shear blade, which has hair entry apertures or slits and is underlaid, in the assembled condition, by a rotating cutter blade, which severs hairs extending into the cutting region of the IE «/50 781 cutter blade through the slits or perforations (apertures) of the shear blade. Each of the shear blades has a particular thickness or depth dimension of the hair entry slits or perforations, so as to provide for a corresponding depth of cut. In conventional dry shavers, the thickness of the shear blade is as small as possible so as to achieve the closest possible shave.

Referring now to Figure 3, there is shown an external cutting member or shear blade 51 of generally conventional configuration. A cutter blade assembly 42 equipped with this type of shear blade 51 maybe regarded as providing a minimum depth of cut, for a tight shave. As shown in this drawing, the shear blade 51, which is in the general shape of a top-hat, or an inverted cup, has a series of generally radiallyoriented, optionally skewed, hair entry slits or apertures 52, in an outwardly-directed generally disc-shaped region 55 of the blade 51, which is upwardly-oriented when incorporated in a cutter blade assembly 42 mounted on a rotary dry shaver 41 as shown in Figure 2. The outer surface of this disc-shaped region 55 of cutting member 51 comes into contact with the skin during a shaving operation. At the periphery of the disc, a generally annular peripheral wall portion 56 extends (downwardly in the mounted condition onshaver 41) to terminate in an externallydirected holding flange 53, by which the shear blade is secured in position on the shaver 41. Centrally of the generally disc-shaped region 55, radially inward of the slits 52, there is a provided a central dished portion 54, which is set back from the skin-engaging surface defined by the outer face of region 55 at the slots 52.

Referring now to Figures 4 and 5, shear blade 61 is generally similar in construction to blade 51, so that blades 51 and 61 are interchangeable on the dry shaver 41 of Figure 2. Shear blade 61 has a series of generally radially-oriented, optionally skewed, hair entry slits or apertures 62, provided on a skin-engaging region 65 thereof. As shown in Figure 4, the skin-engaging region 65 of shear blade 61 comprises a plurality of substantially radially-oriented tines or struts 603. A hair entry opening 62 is provided between each pair of adjacent tines. The skin-engaging region 65 is substantially annular in shape and is upwardly-oriented when incorporated in a cutter blade assembly and mounted on the rotary shaver 41. The outer surface of this skin-engaging region 65 of cutting member 61 thus comes into Κ 05ο79t 9 9 contact with the skin during a shaving operation. Similarly to shear blade 51, shear blade 61 is a provided with an annular peripheral wall portion 66 which extends (downwardly in the mounted condition on shaver 41) to terminate in an externallydirected holding flange 63, by which the shear blade may be mounted on the shaver 41. Centrally of the skin-engaging region 65, radially inward of the slits 62, there is a provided a central portion 64, which is substantially saucer-shaped and is recessed from the skin-engaging surface defined by the outer face of region 65 at the slots 62.

In order to selectively provide for a more generous shave, in other words a less tight or close shave leaving a longer beard length, shear blade 61 varies in thickness about its circumference, as shown in Figures 4 and 5. The thickness of a portion of the skinengaging region 65 of the shear blade 61 is increased relative to the remainder of the skin-engaging region of the shear blade, to create a raised portion 69. In the embodiment shown in Figures 4 and 5, the spacing between the skin-engaging surface of the shear blade and the opposite face thereof is increased over about one third of the circumference of the shear blade. This allows a longer or more generous shave to be achieved when the thicker or raised portion 69 of the shear blade is applied to the face and a closer shave to be achieved when the thinner portion 67 of the skin-engaging region is applied to the face.

The shear blade 61 has two transition regions 601 and 602 wherein the spacing between the skin-engaging surface of the shear blade and the opposite face 68 thereof varies or tapers. If one were to trace an imaginary path around the circumference of shear blade 61 in a clockwise direction, the spacing between the skin-engaging surface of the shear blade and the opposite face 68 thereof would increase at transition region 601 and decrease at transition region 602. In the embodiment shown, each transition region comprises three tines or struts 603.

The only dimensional difference between the shear blades 51 and 61 is in the thickness of the blade in the thicker or raised portion 69. The thickness of each of the tines or struts 603 in this portion of the shear blade 61 is thus increased relative to the remainder of the tines of the shear blade. Slits 62, flange 63 and central region 64 correspond to portions 52, 53 and 54 of the standard cutter 51 of Figure 3. However, !Έ 0S0 79j at portion 69 of shear blade 61, the slits 62 are substantially greater in depth than the slits at portion 67 of shear blade 61, since each slit 62 runs from the skin-engaging surface of the thickened portion through to the opposite face thereof. The slits in portion 69 are thus also greater in depth than the slits 52 of blade 51.

Accordingly, when the raised portion 69 of shear blade 61 is applied to the face, the hairs are cut at a longer length than in the case of the blade 51. In use of this embodiment of the invention, the raised portion 69 of shear blade 61 is to be applied to skin areas where the cut is not to be too tight, so as to avoid the dermatological and other skin problems previously identified, while the thinner portion 67 of shear blade 61 may be used in a similar manner to shear blade 51 to achieve a tight shave and good appearance where this does not create any skin hazard or potential damage.

Figures 6, 7 and 8 illustrate a shaver head 71 of a rotary dry shaver according to an embodiment of the invention in a second aspect. The cutting drive and mounting arrangements of the rotary shaver of the invention are generally in accordance with substantially conventional arrangements well-known in the industry and only the particular deviations from such constructions required by the present invention are now described in detail. The rotary shaver comprises three cutter blade assemblies 72 mounted in a trefoil arrangement within an outer housing 77, which together form a shaver head 71. Each cutter blade assembly includes a shear blade 73 as described above with reference to Figures 4 and 5, and an associated rotary cutter blade. As shown in Figures 7 and 8, each shear blade 73 is moveably mounted within a frame 76, which is tum is moveably mounted within the shaver housing ΊΊ. As shown in Figure 6, the cutter blade assemblies 72 are arranged such that the portion 74 of each assembly which has an increased spacing between the skin-engaging surface of the shear blade and the opposite face thereof (that is, the thicker portion) is oriented centrally of the shaver such that said portions are arranged adjacent one another to provide a central raised shaving plane or platform 75.

The shear blades 73 are resiliently biased upwards, that is, towards the skin-engaging region of the shaver head, the biasing means being substantially conventional and not illustrated. Each shear blade is therefore resiliently downwardly displaceable within *’ί»?», the shaver. The frames 76 are also resiliently biased upwards in a similar manner to the shear blades 73. The frames 76 are thus also resiliently downwardly displaceable within the shaver. The biasing means is such that the shear blade 73 and the frames 76 are effectively floatingly mounted within the housing 77.

As illustrated in Figure 7, each frame 76 is greater in height at its centrally oriented portion 78 than at the outwardly oriented portions 80 thereof. Since the shear blades are biased upwards and are retained in the shaver by the frames 76 within the outer housing 77, each of the cutter blade assemblies 72 is mounted in the shaver head 71 at an angle to the horizontal, such that the central (thicker) portion 74 of each assembly is tilted upwards relative to the outwardly oriented (thinner) portions 79 of each assembly. Thus, each shear blade 73 is thicker at its central portion 74 than at its outwardly oriented portions 79, and is also tilted upwards at its the central portions 74 relative to the outwardly oriented portions 79. When the shaver is first applied to the skin surface to be shaved, the increased thickness of the shear blades and the upward tilt ensures that only the central raised shaving platform 75 engages the skin, providing for a longer or more generous shave.

In order to achieve a close shave, it is necessary to bring the outwardly oriented (thinner) portions 79 of the shear blades into contact with the skin surface. This may be done by exerting pressure on the central raised shaving plane 75, that is, by pressing the shaver head 71 more firmly against the skin surface to be shaved.

Pressure exerted on the central raised shaving plane 75 causes each moveably mounted shear blade and associated moveable frame to be displaced downwardly into the shaver at a central portion thereof thereby allowing the outwardly oriented portions of the shear blades to engage the skin as shown in Figure 8. Since the shear blades are thinner at their outwardly oriented portions, the spacing between the skinengaging surface of each of the shear blades and the opposite face thereof for cooperation with the associated cutter blade is relatively small, and a close shave may be effected.

In use, when the shaver is first applied to the skin surface to be shaved, the central raised platform 75 contacts the skin and may be used to carry out a long or generous IF °S078j shave of the skin surface. Skin irritation and inflammation due to pseudofolliculitis barbae may thus be avoided in areas where hair growth is tangential to the skin. In order to effect a tight shave in areas of the skin where hair growth is perpendicular to the skin, and which are thus not prone to pseudofolliculitis barbae, the user presses the shaver more firmly against the skin. This causes the central raised portions 74 of the shear blades 73 and/or the frames 76 to pivot against their biasing means so that they are tilted downwards, that is, into the shaver body. The thicker raised portions 74 of the shear blades 73 (and the central portions 78 of the frames 76) are thus depressed into the shaver body, such that their skin-engaging surfaces are lowered to substantially the same level as the skin-engaging surfaces of the outer portions 79.

Each shear blade is thus brought to a horizontal or near horizontal position as shown in Figure 8 of the drawings. The thinner outwardly oriented portions 79 of the shear blades 73 are thereby allowed to engage the skin. The spacings between the skinengaging surfaces of the shear blades and the opposite faces thereof in these regions of the shaver are small and a tight shave may therefore be achieved as with a conventional rotary shaver.

The words "comprises/comprising" and the words "having/including" when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

Claims

1. A cutter blade assembly for a rotary shaver comprising: a cutter blade; and a cooperating shear blade arrangement in which provision is made for the spacing between a skin-engaging surface of the cutter blade assembly and regions of the shear blade arrangement which cooperate with the cutter blade to be increased as compared with the spacing required to achieve a “close shave”; and characterised in that the cutter blade is a rotary cutter blade; and the cutter blade has an overlying cooperating shear blade; wherein the spacing between a skin-engaging surface of the shear blade and the opposite face thereof for co-operation with the associated cutter blade varies about the circumference of the shear blade such that the spacing between a portion of the skin engaging surface of the shear blade and the opposite face thereof is increased as compared with the spacing required to achieve a “close shave”.

2. A cutter blade assembly as claimed in claim 1, wherein the spacing between the skin engaging surface of the shear blade and the opposite face thereof is increased as compared with the spacing required to achieve a “close shave” over one third to one eighth of the circumference of the shear blade.

3. A cutter blade assembly as claimed in claim 2, wherein the spacing between the skinengaging surface of the shear blade and the opposite face thereof is increased as compared with the spacing required to achieve a “close shave” over about one quarter of the circumference of the shear blade.

4. A cutter blade assembly as claimed in any preceding claim, comprising two transition regions wherein the spacing between the skin-engaging surface of the shear blade and the opposite face thereof is increasing or decreasing, respectively.

5. A cutter blade assembly as claimed claim 4, wherein the spacing between the skinengaging surface of the shear blade and the opposite face thereof varies gradually about the circumference of the shear blade, such that said transition regions are relatively long.

6. A cutter blade assembly as claimed in claim 4, wherein the spacing between the skinengaging surface of the shear blade and the opposite face thereof changes abruptly at two positions on the circumference of the shear blade, such that said transition regions are relatively short.

7. A cutter blade assembly as claimed in any preceding claim, wherein the shear blade comprises a plurality of radially-oriented hair entry openings extending from the skin-engaging surface of the shear blade to the opposite face thereof.

8. A cutter blade assembly as claimed in claim 7, wherein the shear blade comprises a plurality of substantially radially-oriented tines and wherein a hair entry opening is provided between each pair of adjacent tines.

9. A cutter blade assembly as claimed in claim 8 wherein said the thickness of the tines varies about the circumference of the shear blade such that the spacing between a portion of the skin engaging surface of the shear blade and the opposite face thereof is increased as compared with the spacing required to achieve a “close shave”.

10. A cutter blade assembly as claimed in any of claims 7 to 9, wherein each transition region comprises between two and five tines.

11. .A rotary dry shaver comprising: a housing; and a plurality of cutter blade assemblies according to any of claims 1 to 10 mounted within the housing; wherein the cutter blade assemblies are arranged such that the portion of each assembly which has an increased spacing between the skin-engaging surface of the shear blade and the opposite face thereof is oriented centrally of the shaver such that said portions are arranged adjacent one another to provide a central raised shaving platform. ,r

12.A rotary dry shaver as claimed in claim 11, comprising three cutter blade assemblies mounted within the housing in a trefoil arrangement. 5

13.A rotary dry shaver as claimed in claim 11 or claim 12, wherein the cutter blade assemblies are moveably mounted within the housing such that the central portion of each shear blade is downwardly displaceable to allow outwardly oriented portions of the shear blade to engage the skin to achieve a “close shave”. 10

14.A rotary dry shaver as claimed in claim 13, wherein the shear blade of each cutter blade assembly is resiliently upwardly biased, such that each shear blade is resiliently downwardly displaceable within the shaver.

15. A rotary dry shaver as claimed in any of claims 11 to 14, wherein each cutter blade 15 assembly is moveably mounted within a frame, and each frame is moveably mounted within the housing.

16. A rotary dry shaver as claimed in claim 16, wherein each frame is resiliently upwardly biased, such that each frame is resiliently downwardly displaceable within 20 the shaver.

17. A rotary dry shaver as claimed in claim 15 or claim 16, wherein a central portion of each frame is greater in height than outwardly oriented portions of the frame, such that the central portion of each cutter blade assembly is tilted upwards relative to 25 outwardly oriented portions of the cutter blade assembly.

18. A cutter blade assembly substantially as hereinbefore described with reference to and/or as illustrated in Figures 4 and 5 of the accompanying drawings. 30

19. A rotary dry shaver substantially as hereinbefore described with reference to and/or as illustrated in Figures 6, 7 and 8 of the accompanying drawings. TOMKINS & CO