Shaving head with doming control

Patent metadata

Field	Value
Publication number	US-9873204-B2
Application number	US-201214363674-A
Country	US
Kind code	B2
Filing date	Dec 12, 2012
Priority date	Dec 19, 2011
Publication date	Jan 23, 2018
Grant date	Jan 23, 2018

Abstract

A cutter unit ( 1 ) for a rotary shaver is formed by an outer cutting element or cap ( 2 ) which interacts with a rotating inner cutting element or cutter ( 4 ) to trap and cut hairs. The cap has an annular shaving track ( 8 ) of domed cross-section having slots ( 30 ) through which the hairs may protrude. The cutter has a convex upper face ( 22 ) to engage the shaving track and a concave forward face ( 26 ).

First claim

The invention claimed is:

1. A rotary shaver, comprising:
a cap comprising one or more annular shaving tracks, the one or more annular shaving tracks comprising a plurality of slots, each slot oriented at an angle (β) to a radial direction with respect to the axis of rotation, each track having a domed shaped upper surface and a curved shaped lower surface,
a cutter unit, comprising a support member having an axis of rotation and carrying a plurality of cutting elements each cutting element comprising:
a leg portion, and
a distal portion adjacent the leg portion, wherein the distal portion comprises:
an upper face that is convex having a partial circular cylindrical shape and partially flat in a circumferential direction in a plane perpendicular to a direction of movement, said upper face terminating in a cutting edge lying in a radial plane and wherein said upper face and said cutting edge have a first radius of curvature R,
a forward face, having a slightly concave shape angled at a cutter angle (α) with respect to a direction of movement of the leg portion relative to the axis of rotation of the support member, wherein the cutter angle (α) is between 40° and 50°, said forward face having a second radius of curvature r,

wherein said upper face intersects the forward face in said cutting edge forming a straight line when viewed in a vertical direction at least over a portion intended to contact the shaving track formed in the cap, thus allowing a constant shearing angle β over over the radial extent of the cutter by ensuring that R=r·cos(α),
wherein the second radius of curvature r depends on the cutter angle (α) such that R=r cos(α) such that the cutting edge will be located at an intersection of the forward face and the upper face.

2. The rotary shaver of claim 1 , wherein the curved lower surface has a different profile to the upper surface.

3. The rotary shaver of claim 1 , wherein the cutting edge and a cutting surface of at least one of the slots are angled with respect to each other at a shearing angle (β) and the shearing angle is constant over a radial extent of said at least one of the slots.

4. The rotary shaver according to claim 1 , comprising at least two cutter units, each of said at least two cutter units comprising a drive unit to cause rotation of the cutter(s) of the at least two cutter units.

5. The rotary shaver according to claim 1 , comprising three cutter units arranged at the vertices of an equilateral triangle.

6. A cutter unit, comprising:
a support member having an axis of rotation and carrying a plurality of cutting elements each cutting element comprising:
a leg portion, and
a distal portion adjacent the leg portion, wherein the distal portion comprises:
an upper face that is convex having a partial circular cylindrical shape and partially flat in a circumferential direction in a plane perpendicular to a direction of movement, said upper face terminating in a cutting edge lying in a radial plane and wherein said upper face and said cutting edge have a first radius of curvature R,
a forward face, having a slightly concave shape angled at a cutter angle (α) with respect to a direction of movement of the leg portion relative to the axis of rotation of the support member, wherein the cutter angle (α) is between 40° and 50°, said forward face having a second radius of curvature r,

wherein said upper face intersects the forward face in said cutting edge forming a straight line when viewed in a vertical direction at least over a portion intended to contact the shaving track formed in the cap, thus allowing a constant shearing angle β over over the radial extent of the cutter by ensuring that R=r·cos(α),
wherein the second radius of curvature r depends on the cutter angle (α) such that R=r cos(α) such that the cutting edge will be located at an intersection of the forward face and the upper face.

7. The cutter unit according to claim 6 , wherein the cutting edge and a cutting surface of at least one of the slots are angled with respect to each other at a shearing angle (β) and the shearing angle is constant over a radial extent of said at least one of a plurality of slots of a cap having one or more annular shaving tracks comprising a plurality of slots.

Assignees

• Koninklijke Philips Nv

Inventors

• Zuider Jasper
• Godlieb Robert
• Hoitinga Onno

Classifications

• B26B19/141 Primary

  Details of inner cutters having their axes of rotation perpendicular to the cutting surface · CPC title

• B26B19/143

  Details of outer cutters · CPC title

• B26B19/14 Primary

  of the rotary-cutter type; Cutting heads therefor; Cutters therefor (B26B19/04 takes precedence) · CPC title

• A45D26/00

  Hair-singeing apparatus; Apparatus for removing superfluous hair, e.g. tweezers (removing hair using electrosurgical instruments A61B18/04, A61B18/18) · CPC title