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US3740843A - Shaving head having separately sprung blades - Google Patents

Shaving head having separately sprung blades Download PDF

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Publication number
US3740843A
US3740843A US00117502A US3740843DA US3740843A US 3740843 A US3740843 A US 3740843A US 00117502 A US00117502 A US 00117502A US 3740843D A US3740843D A US 3740843DA US 3740843 A US3740843 A US 3740843A
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US
United States
Prior art keywords
blade
axis
center
carrier
rotation
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00117502A
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English (en)
Inventor
E Tietjens
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
US Philips Corp
Original Assignee
US Philips Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by US Philips Corp filed Critical US Philips Corp
Application granted granted Critical
Publication of US3740843A publication Critical patent/US3740843A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
    • B26B—HAND-HELD CUTTING TOOLS NOT OTHERWISE PROVIDED FOR
    • B26B19/00—Clippers or shavers operating with a plurality of cutting edges, e.g. hair clippers, dry shavers
    • B26B19/14—Clippers or shavers operating with a plurality of cutting edges, e.g. hair clippers, dry shavers of the rotary-cutter type; Cutting heads therefor; Cutters therefor
    • B26B19/145—Cutters being movable in the cutting head
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B26—HAND CUTTING TOOLS; CUTTING; SEVERING
    • B26B—HAND-HELD CUTTING TOOLS NOT OTHERWISE PROVIDED FOR
    • B26B19/00—Clippers or shavers operating with a plurality of cutting edges, e.g. hair clippers, dry shavers
    • B26B19/14—Clippers or shavers operating with a plurality of cutting edges, e.g. hair clippers, dry shavers of the rotary-cutter type; Cutting heads therefor; Cutters therefor
    • B26B19/141—Details of inner cutters having their axes of rotation perpendicular to the cutting surface

Definitions

  • ABSTRACT relates to a shaving head for a dryshaving apparatus comprising a circular shear plate and a cutter member which co-operates with the shear plate and has at least one separately sprung blade the body of which is arranged so as to be movable in an opening in a rotatably drivable blade carrier; in operation the cutting edge of the blade, which edge extends substantially in a radial direction, resiliently engages the shear plate, which is spaced from the blade carrier.
  • the perforated shear plate is secured to the upper part of a shaver head housing that generally surrounds the blade carrier and the end of the electric motor output shaft that drives the blade carrier.
  • whiskers extend through hair receiving perforations in the shear plate and are severed when sheared between a cutter blade and the shear plate.
  • dry-shaving apparatus in general requires a close engagement between the blade and the shear plate during the cutting operation, i.e., a stable equilibrium between the blade and the shear plate in this position of engagement, because the entire shaving process takes place in the plane of contact between the blade and the shear plate.
  • the blade is mounted so as to be tiltable substantially in the radial direction during cutting within a hair is momentarily positioned between a blade and the shear plate, and the blade's cutting edge is resiliently held in engagement with the shear plate during both idling and in the inoperative condition.
  • the invention is characterized in that the center of gravity of the blade is located with respect to the disc-shaped blade carrier, that a centrifugal force which is produced in operation by the rotation and acts through the centre of gravity, produces a restoring force which increases on further deviation and tends to position the body of the blade so that that comparatively weak thrust spring which co-operates with the blade and exerts a force which is directed towards the shear plate and is of the order of magnitude of the inertial forces exerted on the blade but exceeds them, is enabled to achieve a renewed position of engagement between the cutting edge of the blade and the shear plate.
  • the thrust spring for the blade has a comparatively small force and is required substantially only to ensure correct engagement between the blade and the shear plate in the inoperative condition, while initial deviation from this engagement inthe radial direction during idling or during cutting will usually be corrected at the very beginnigng by a couple which results in a restoring force which increases with increase in deviation.
  • FIG. 1 is a longitudinal sectional view of a shaving head taken in a plane containing the axis
  • FIG. 2 shows on an enlarged scale a detail of FIG. 1,
  • FIG. 3 shows the same detail but with the blade tilted
  • FIG. 4 shows the shaver head in assembled form.
  • a shaving head 1 which comprises a rotably drivable cutting member 2, which cooperates with a circular rigid or flexible shear plate 3, for example a shear foil within a housing 1 that generally supports the plate.
  • the cutting member 2 is constituted by a disc-shaped blade carrier 4 which has a flat upper surface 5 and a parallel flat lower surface 6, is rotatable about an axis of rotation 7 by a drive shaft 7' (FIG. 4) and is formed with an opening 8 whice extends in the axial direction throughout the entire thickness of the carrier 4 and in which a blade 9 having a cutting edge 10 and a body 11 is mounted movably and substantially radially tiltably.
  • the cutting edge 10 of the blade 9 is held in engagement with the sjear plate 3 by a thrust spring 12.
  • the body 1 1 of the blade 9 has inward surface 17 and outer surface 13 more remote from the axis of rotation 7 of the blade carrier 4.
  • Surface 13 is accurate, and the blade 9 is proportioned so that the following points of the blade lie substantially in one line: the middle 16 of the are 13, the center of gravity 15 of the blade 9, and the center 14 of the are 13.
  • this line substantially coincides with the line ofintersection of the longitudinal section shown with the plane containing the axis of the blade carrier 4 and extending at right angles to the plane of the drawing; preferably the center 14 of the are 13 lies between the axis of rotation 7 and that surface 17 of the blade 9 which faces the axis of rotation 7, so that the distance R between the centre 14 of the arc 13 and the middle 16 of the arc l3 considerably exceeds the distance Z between the centre of gravity 15 and the said middle 16.
  • the blade 9 engages the wall of the opening 8 that is remote from the axis of rotation 7, when the blade 9 is urged in operation by the centrifugal force produced.
  • FIG. 3 shows the blade 9 in an exaggerated radially tilted position which it is assumed to have up in operation.
  • a centrifugal force C acts through the center of gravity 15 in a horizontal direction in the plane of the drawing and a reaction force K acts in a direction towards the centre 14' of the are at the point 19.
  • This reaction force may be resolved into vectors V and V V extending horizontally also but in a direction opposite to that of the force C.
  • the forces C and V form a counter-clockwise torque which tends to return the blade 9 to its initial position.
  • the value of this torque increases with increase in the vertical distance between the points 15 and 19, which means that an increasing departure of the blade 9 from its initial engaged position gives rise to an increasing restoring effect.
  • the vector V must naturally be maintained as small as possible, and this is obtainable by keeping the deviation of the curve 13 from a straight line to a minimum, with the restriction that there must be a point or line contact between the surface 13 and the relevant wall of the opening 8.
  • Practice has shown that with a curvature of the arc 13 such that in the initial position its centre lies between the axis of rotation 7 and the surface 17 of the blade 9 facing the axis of rotation 7, restoring forces of acceptable value will be produced.
  • the discrepancy between the torques will be understood by realizing that the disc-shaped blade carrier 4 may be driven at a speed of 4,000 revolutions per minute.
  • the thrust spring 12 has a comparatively small force, because it is only required to overcome the inertial forces exerted on the blade 9 and the friction between the curved surface 13 and the respective wall of the opening 8.
  • the center of gracity 15 need not exactly lie in a plane which contains the axis of the blade carrier and extends at right angles to the plane of the drawingg.
  • a requirement is, however, that at any deviation of the blade 9 the center of gravity 15 should remain within that part of the volume of the opening 8 which is bounded by the upper and lower surfaces of the blade carrier 4. This means that a stable equilibrium between the blade and the shear plate is obtainable even with comparatively large manufacturing tolerances, which considerably restricts the cost of manufacture.
  • the invention is not restricted to the embodiment shown in the drawings.
  • the cutting edge 10 of the blade 9 may be slightly inclined with respect to the shear plate 3, and this embodiment in conjunction with the use of a shear plate in the form of a shear foil has yielded highly satisfactory shaving results, as practice has shown.
  • a shaving head for use with a dry shaver which includes a housing and a drive means for operating said shaving head, the shaving head comprising, a shear plate supported by the housing, a blade carrier within said housing and rotatably driveable about its axis of rotation by said drive means, the blade-carrier having top and bottom surfaces axially spaced along said axis, and a plurality of openings formed as slots extending between said top and bottom surfaces, each slot having (i) spaced apart sides that defined a planar space generally parallel to said axis, and (ii) inner and outer edge surfaces respectively closer to and remote from said axis of rotation, a plurality of blades each positionable in one of said openings and tippable within said space, each.
  • each blade having an upper cutting edge for engagement with said shear plate, and inner and outer edges adjacent to corresponding edges of an associated opening, each blade having a center of gravity, the blade when rotated by said blade carrier subject to centrifugal forces (a) which act at its center of gravity urging it generally outward of said axis, and (b) which form part of a couple urging the blade back to its non-tipped position when it has become tipped in operation, and spring means urging each blade axially toward said shear plate, the spring force being of the same order of magnitude and slightly greater than inertial forces acting on said blade.
  • a shaving head for use with a dry shaver including a housing and drive means for operating said shaving head comprising a blade carrier rotatably driveable about its axis of rotation by said drive means, a shear plate supported by said housing and orientated generally normal to said axis, at least one blade carried by said blade carrier in a plane generally parallel to said shear plate, each blade having a top edge adjacent the shear plate, and inner and outer edges respectively near and remote from said axis of rotation, the carrier having a support edge adjacent and corresponding to said outer edge of said blade, one of said support and outer edges being convex and the other generally flat, the blade having a center of gravity near the center of the blade, whereby the blade when rotated by the bladecarrier has a centrifugal force acting through said center of' gravity urging said center of the blade toward said support edge.
  • a shaving head for use with a dry shaver which includes a housing and a drive means for operating said shaving head, comprising, a shear plate supported by the housing, a blade carrier within said housing and rotatably driveable about its axis of rotation by said drive means, the blade-carrier having top and bottom surfaces axially spaced along said axis, and a plurality of openings formed as slots extending between said top and bottom surfaces, each slot having (i) spaced apart sides that define a planar space generally parallel to said axis, and (ii) inner and outer edge surfaces respectively closer to and remote from said axis of rotation, a plurality of blades each positionable in one of said openings and tippable within said space during cutting operation, each blade having a center of gravity, the blade when rotated by said blade-carrier subject to centrifugal forces which act at its center of gravity urging it generally outward of said axis, and which form a part of a couple urging the blade back to its non-tipped position when it
  • Apparatus according to claim 4 wherein the center of said are lies between said axis of rotation and the inner blade edge.
  • each blade is radially spaced from said axis of rotation.
  • each blade is radially spaced from said axis of rotation and located in a radial plane extending through said axis of rotation.

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  • Life Sciences & Earth Sciences (AREA)
  • Forests & Forestry (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Dry Shavers And Clippers (AREA)
US00117502A 1970-03-25 1971-02-22 Shaving head having separately sprung blades Expired - Lifetime US3740843A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL7004336A NL7004336A (fr) 1970-03-25 1970-03-25

Publications (1)

Publication Number Publication Date
US3740843A true US3740843A (en) 1973-06-26

Family

ID=19809678

Family Applications (1)

Application Number Title Priority Date Filing Date
US00117502A Expired - Lifetime US3740843A (en) 1970-03-25 1971-02-22 Shaving head having separately sprung blades

Country Status (11)

Country Link
US (1) US3740843A (fr)
JP (1) JPS5243146B1 (fr)
AT (1) AT310034B (fr)
BE (1) BE764726A (fr)
CA (1) CA941148A (fr)
CH (1) CH531399A (fr)
DE (1) DE2110101C3 (fr)
ES (1) ES194173Y (fr)
FR (1) FR2085129A5 (fr)
GB (1) GB1307670A (fr)
NL (1) NL7004336A (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3858316A (en) * 1971-09-25 1975-01-07 Eduard Willem Tietjens Shaving head having separately sprung blades
US20050257376A1 (en) * 2002-07-29 2005-11-24 Koninklijke Philips Electronics N. V. Shaving apparatus
US20080016690A1 (en) * 2004-06-21 2008-01-24 Koninklijke Philips Electronics N.V. Shaving Apparatus
US20100275446A1 (en) * 2009-04-29 2010-11-04 Rovcal, Inc. Rotary electric shaver

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3858316A (en) * 1971-09-25 1975-01-07 Eduard Willem Tietjens Shaving head having separately sprung blades
US20050257376A1 (en) * 2002-07-29 2005-11-24 Koninklijke Philips Electronics N. V. Shaving apparatus
US7698819B2 (en) * 2002-07-29 2010-04-20 Koninklijke Philips Electronics N.V. Shaving apparatus
US20080016690A1 (en) * 2004-06-21 2008-01-24 Koninklijke Philips Electronics N.V. Shaving Apparatus
US8191264B2 (en) * 2004-06-21 2012-06-05 Koninklijke Philips Electronics N.V. Shaving apparatus
US20100275446A1 (en) * 2009-04-29 2010-11-04 Rovcal, Inc. Rotary electric shaver

Also Published As

Publication number Publication date
DE2110101B2 (de) 1978-01-12
NL7004336A (fr) 1971-09-28
JPS5243146B1 (fr) 1977-10-28
CH531399A (de) 1972-12-15
FR2085129A5 (fr) 1971-12-17
GB1307670A (en) 1973-02-21
ES194173Y (es) 1975-03-01
DE2110101A1 (de) 1971-10-14
DE2110101C3 (de) 1978-08-24
AT310034B (de) 1973-09-10
ES194173U (es) 1974-11-16
BE764726A (fr) 1971-09-23
CA941148A (en) 1974-02-05

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