AU2005205800B2 - Shaving razor and blade unit with improved guard - Google Patents

Description

S&F Ref: 605074D1

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: The Gillette Company, of Prudential Tower Building, Boston, Massachusetts, 02199, United States of America Stephen C Metcalf Vincent P. Walker Jr.

Spruson Ferguson St Martins Tower Level 31 Market Street Sydney NSW 2000 (CCN 3710000177) Shaving razor and blade unit with improved guard The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5845c b SHAVING RAZOR AND BLADE UNIT WITH IMPROVED GUARD r The invention relates to a shaving razor and a blade unit therefor with an improved guard.

Shaving razors often consist of a handle and a replaceable cartridge in which one s or more blades are mounted in a plastic housing. U.S. Patent No. 5,918,369 describes a shaving razor including a replaceable cartridge that has a blade unit that is pivotally Sconnected to an interconnect member that is in turn connected to a handle. The blade unit 00 i" includes a guard having resilient fins in front of the blades to engage the skin surface and a lubricating strip behind the blades.

It is the object of the present invention to substantially overcome or at least ameliorate one or more of the disadvantages of the prior art.

Accordingly, in a first aspect, the present invention provides a blade unit for a shaving razor, including a housing, a guard at the front of the housing, a cap at the rear of the housing, and a plurality of parallel blades supported by the housing between the guard and the cap and having respective cutting edges, wherein the guard includes a plurality of rows of elongated, elastomeric fins arranged generally parallel to said cutting edge, said fins being the last skin engaging structure contacted by a user's skin before contacting said blades, and said fins having base to tip heights less than 0.15 mm.

In a second aspect, the present invention provides a shaving razor comprising a handle and a blade unit, according to the first aspect, connected to the handle.

Particular embodiments of the invention may include one or more of the following features. The elastomeric fins are small fins which also have a base to tip height of less than 0.15 mm. Preferably these small fins have a base to tip height of between 0.06 and 0.08 mm. Preferably there are at least three fins.

Preferably the blades are movably mounted with respect to the housing.

Preferably the blade unit is connected to a pivotal structure to permit the blades in to pivot with respect to a handle.

Embodiments of the invention may include one or more of the following advantages. The fins tend to stimulate and stretch the skin in front of the blades, tending to improve comfort and proper positioning of the skin for cutting of hairs. The fins that provide a resilient structure as the last skin contacting member before engagement by the first blade act to improve skin stretching and improve comfort. In addition, the user can adjust the geometry of the exposure of the first blade and the blade tangent angle by pressing harder on the elastomeric fins that are the last skin contacting structure before the blade. Increasing the elevation of fins tends to gradually increase skin contact and 875333 I:TCW causes the tips to conform to the skin flow during shaving. The narrow included angle

C

profile of the larger fins improves fin flexibility, which helps to stretch the skin, thereby Ssetting up the hairs for improved cutting. The use of a large number of fins improves skin engagement.

Preferred forms of the present invention will now be described by way of examples only, with reference to the accompanying drawings, wherein: FIG. 1 is a perspective view of a shaving razor.

00 FIG. 2 is a perspective view of a replaceable cartridge of the FIG. 1 it [R:\LIBLL] 17380.doc:TCW -3r razor.

FIG. 3 is a vertical sectional view of the blade unit of the FIG. 2 1 replaceable cartridge.

FIG. 4 is a vertical sectional view of the guard of the FIG. 3 blade unit.

SFIG. 5 is an enlarged partial vertical sectional view of small fins of 00 tt) the FIG. 4 guard.

NReferring to FIG.'s 1 and 2, shaving razor 10 includes handle 12 and replaceable shaving cartridge 14. As shown in FIG. 2, cartridge 14 is removable from handle 12. Cartridge 14 includes housing 16, which carries three blades 18, guard 20 and cap 22. Cartridge 14 also includes interconnect member 24 on which housing 16 is pivotally;mounted about a pivot axis. Interconnect member 24 includes a base 27 which is connected to handle 12. Base 27 has two arms 28 that pivotally support housing 16 at its two sides.

Referring to FIG.'s 3 and 4, it is seen that guard 20 includes two groups 30,32 of large fins 34 and a further group of'small fins 36. Guard 20 is made of material having Shore A hardness of 30 to 60 (preferably 40 to 50, most preferably about 49. As values are increased above this range, performance may tend to deteriorate, and as values are decreased below this range, there may be production problems. Each group 30,32 of large fins preferably includes at least three fins, most preferably about four fins. The tips 40 of the leading group of large fins 30 increase in elevation with respect to plane 42, which passes through the cutting edges of the blades 18, while the tips 44 of the trailing group of large fins 32 have a uniform elevation. A line passing through the tips 40 of the leading group of large fins 30 makes an angle of 14 degrees with plane 42. The tips 40 of the leading group of large fins 30 include some tips that are below plane 42 and some tips that are above plane 40. The tips 44 of the trailing group of large fins 32 are all above plane 40, preferably about 0.22 mm above plane 42. Fins 34 have a tip to base height of 0.4 mm to 0.8 mm (more preferably between 0.6 mm and 0.7 mm, and most preferably about 0.66 mm), a base thickness of 0.15 to 0.25 mm (most preferably 0.19 mm) an included angle of less than 14 degrees, preferably about 12 degrees, and are spaced center to center by about 0.39 mm. The distance -4u from the front of the first fin 34 to the back of the last fin 34 at the base is 2.95 mm. Alternatively, this distance can be from 2.0 mm to 3.5 mm.

SReferring to Fig. 5, the group of small fins 36 have a uniform elevation with respect to plane 42. They have a height h of less than 0.15 mm, preferably 0.06 mm to 0.08 mm (most preferably 0.065 mm), a base thickness of 0.04 mm to 0.03 mm (preferably about 0.06 mm), a tip radius of one half the base 00 t (preferably 0.03 mm) and are spaced center to center by about a distance of between S0.05 mm and 0.15 mm, most preferably about 1.0 mm. The base to tip height of the third group of small fins 36 preferably is less than 1/5 of the base to tip height Ni 10 of large fins 30,32. At least part of the elastomeric portion underlining fins 36 in his preferably supported by the hard plastic of housing 16. Preferably the distance from the top of the fin to the top of the plastic housing 16 is about 0.1 mm to 0.3 mm (most preferably about 0.15 mm). The tips of fins 36 are about 0.07 mm above plane 42. Fins 36 are the last skin engaging structure contacted by a user's skin before contacting blades 18.

In use, the large fins 30 and 32 tend to stimulate and stretch the skin in front of the blades, tending to improve comfort and proper positioning of the skin for cutting of hairs. The increasing elevation of fins 30 tends to gradually increase skin contact. The uniform elevation of fins 32 provides consistent skin contact.

The narrow 12 degree profile improves fin flexibility. The use of a large number of fins greater than 6 and preferably around improves skin engagement.

The small tins 36 provide a resilient structure as the last skin contacting member before engagement by the first blade, to improve skin stretching and improve comfort. In addition, the user can adjust the geometry of the exposure of the first blade and the blade tangent angle by pressing harder, thereby comprising the resilient fins.

Other advantages of the invention are within the scope of the appended claims.

Claims (10)

1. A blade unit for a shaving razor, including a housing, a guard at the front of the housing, a cap at the rear of the housing, and a plurality of parallel blades supported by the housing between the guard and the cap and having respective cutting edges, wherein the guard includes a plurality of rows of elongated, elastomeric fins arranged generally parallel to said cutting edge, said fins being the last skin engaging structure contacted by a user's skin before contacting said blades, and said fins having base to tip heights less than 0.15 mm.

2. A blade unit according to claim 1, wherein said fins have base to tip 1o heights of between 0.06 and 0.08 mm.

3. A blade unit according to claim 1 or 2, wherein said fins have a radius of curvature at the tips that is about one-half of the width of the fins.

4. A blade unit according to any one of claims 1 to 3, wherein there are at least three fins.

5. A blade unit according to any one of claims 1 to 4, wherein said blades are movably mounted with respect to said housing.

6. A blade unit according to claim 1, wherein the blade unit is connected to a pivotal structure to permit said blades to pivot with respect to a handle.

7. A blade unit according to any one of claims 1 to 3, wherein said fins are made of material having a Shore A hardness of between 30 and

8. A shaving razor including a handle and a blade unit according to claim 1 connected to said handle.

9. A blade unit for a shaving razor substantially as hereinbefore described with reference to the accompanying drawings.

10. A shaving razor substantially as hereinbefore described with reference to the accompanying drawings. Dated 23 July, 2007 The Gillette Company Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON 875333 I:TCW