U.S. patent number 3,871,077 [Application Number 05/355,307] was granted by the patent office on 1975-03-18 for razor with movable guard and concurrently movable blade platform.
This patent grant is currently assigned to The Gillette Company. Invention is credited to Warren I. Nissen, Roger L. Perry.
United States Patent |
3,871,077 |
Nissen , et al. |
March 18, 1975 |
Razor with movable guard and concurrently movable blade
platform
Abstract
A safety razor having a head portion including blade positioning
structure arranged to permit the blade cutting edge to move
relative to the head portion and including biasing means for urging
the blade towards a first position of normal exposure and a guard
member mounted for movement between first and second positions. The
guard member is disposed to engage the blade positioning structure
so that movement of the guard member causes movement of the blade
cutting edge.
Inventors: |
Nissen; Warren I. (Topsfield,
MA), Perry; Roger L. (Lynnfield, MA) |
Assignee: |
The Gillette Company (Boston,
MA)
|
Family
ID: |
23396984 |
Appl.
No.: |
05/355,307 |
Filed: |
April 30, 1973 |
Current U.S.
Class: |
30/63; 30/77 |
Current CPC
Class: |
B26B
21/4018 (20130101); B26B 21/4031 (20130101); B26B
21/4062 (20130101); B26B 21/4068 (20130101) |
Current International
Class: |
B26B
21/40 (20060101); B26B 21/00 (20060101); B26b
021/24 () |
Field of
Search: |
;30/40.2,62,63,64,75,77,81,83 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Smith; Al Lawrence
Assistant Examiner: Smith; Gary L.
Claims
We claim:
1. A safety razor having a head portion including blade positioning
structure, said blade positioning structure being arranged to
permit the blade cutting edge to move relative to said head portion
and including biasing means for urging the blade towards a first
position of normal exposure, and a guard member mounted for
movement between first and second positions to change the blade
tangent angle of the shaving geometry, said guard member disposed
to engage said blade positioning structure, movement of said guard
member causing concurrent movement of said blade cutting edge
relative to said guard member and to said head portion and against
the force of said biasing means to maintain substantially constant
cutting edge exposure.
2. A safety razor for use with a blade comprising
a generally hollow body member including first and second upper
internal bearing portions and a lower internal bearing portion,
said upper bearing portions for slidingly engaging the blade;
blade positioning structure arranged to permit the blade cutting
edge to move relative to said body member and comprising
a blade support unit including a blade receiving surface for
receiving a blade thereupon and elongated structure below said
blade receiving surface having a bearing surface remote from said
blade receiving surface and slidingly engaging said lower internal
bearing portion of said body member,
a spring clamp including a first portion which overlies said blade
receiving surface and second and third portions which engage said
elongated structure of said blade support unit, stress within said
clamp produced by the engagement of said second and third portions
with said elongated structure operative to exert a clamping force
by said first portion upon a blade disposed upon said blade
receiving surface, and
spring means disposed in engagement with said spring clamp and
exerting a force generally in the direction of said blade receiving
surface of said support unit, to slide said blade positioning
structure along said body member bearing portions to urge said
blade receiving surface to a forward position in which a blade
received thereupon has a normal exposure; and
a guard member mounted adjacent the blade cutting edge for movement
between first and second positions and disposed to engage said
blade support unit, whereby movement of said guard member causes
sliding movement of said blade support unit along said body member
bearing portions against the influence of said spring means.
3. A safety razor comprising body structure having a first internal
bearing portion and a second internal bearing portion positioned
below and to the rear of said first internal bearing portion,
blade support structure disposed in said body structure including a
surface adapted to support a blade and being movable as a unit
relative to said body structure, said support structure including a
first bearing surface for engagement with said first bearing
portion, and a second bearing surface positioned beneath and to the
rear of said first bearing surface for engagement with said second
bearing portion, said support structure normally being in
engagement with said first and second bearing portions and spaced
from other portions of said body structure,
biasing means separate from said blade support structure in
engagement with said body structure and exerting an upward force on
said support structure, said biasing means tending to urge said
first bearing surface to slide forwardly across said first bearing
portion, and
stop structure for limiting the forward movement of said blade
support structure under the influence of said biasing means and
positioning the cutting edge of a blade supported on said blade
support structure in predetermined position relative to said body
structure.
4. A safety razor comprising body structure having a first internal
bearing portion and a second internal bearing portion positioned
below and to the rear of said first internal bearing portion,
blade support structure disposed in said body structure including a
surface adapted to support a blade and being movable as a unit
relative to said body structure, said support structure including a
first bearing surface for engagement with said first bearing
portion, and a second bearing surface positioned beneath and to the
rear of said first bearing surface for engagement with said second
bearing portion, said support structure normally being in
engagement with said first and second bearing portions and spaced
from other portions of said body structure,
biasing means in engagement with said body structure and exerting
an upward force on said support structure, said biasing means
tending to urge said first bearing surface to slide forwardly
across said first bearing portion, and
stop structure for limiting the forward movement of said blade
support structure under the influence of said biasing means and
positioning the cutting edge of a blade supported on said blade
support structure in predetermined position relative to said body
structure, said stop structure being movable relative to said body
structure and including a guard member, said guard member being
movable relative to said blade support structure to change the
blade tangent angle of the shaving geometry of the shaving system
and concurrently moving said blade support structure to maintain
substantially constant cutting edge exposure.
5. The razor as claimed in claim 4 wherein said stop structure is
mounted for rotational movement.
6. The razor as claimed in claim 4 wherein said stop structure
includes guard surfaces forward and rearward of said predetermined
edge position.
7. A safety razor comprising body structure having a first internal
bearing portion and a second internal bearing portion positioned
below and to the rear of said first internal bearing portion,
blade support structure disposed in said body structure and being
movable as a unit relative to said body structure, said support
structure including a surface adapted to support a blade, a
reference surface, a spring member for biasing a blade positioned
on said support surface to urge an edge of said blade into
engagement with said reference surface, a first bearing surface for
engagement with said first bearing portion, and a second bearing
surface positioned beneath and to the rear of said first bearing
surface for engagement with said second bearing portion, said
support structure normally being in engagement with said first and
second bearing portions and spaced from other portions of said body
structure,
biasing means in engagement with said body structure and exerting
an upward force on said support structure, said biasing means
tending to urge said first bearing surface to slide forwardly
across said first bearing portion, and
stop structure for limiting the forward movement of said blade
support structure under the influence of said biasing means and
positioning the cutting edge of a blade supported on said blade
support structure in predetermined position relative to said body
structure.
8. A safety razor comprising body structure having a first internal
bearing portion, a second internal bearing portion positioned below
and to the rear of said first internal bearing portion, and an
aperture for receiving a dispenser key,
blade support structure disposed in said body structure including a
surface adapted to support a blade and being movable as a unit
relative to said body structure, said support structure including a
reference surface, a spring member for biasing a blade positioned
on said support surface to urge an edge of said blade into
engagement with said reference surface, said spring member having a
projecting portion extending rearwardly of said blade support
structure and spaced from a surface of said body structure, a first
bearing surface for engagement with said first bearing portion, a
second bearing surface positioned beneath and to the rear of said
first bearing surface for engagement with said second bearing
portion, said support structure normally being in engagement with
said first and second bearing portions and spaced from other
portions of said body structure, a cam surface engageable with said
injector key, said cam surface as engaged by said dispenser key
tending to force said blade support structure rearwardly to cause
said projecting portion to engage said body structure and reduce
the clamping force exerted by said spring member on said blade,
biasing means in engagement with said body structure and exerting
an upward force on said support structure, said biasing means
tending to urge said first bearing surface to slide forwardly
across said first bearing portion, and
stop structure for limiting the forward movement of said blade
support structure under the influence of said biasing means and
positioning the cutting edge of a blade supported on said blade
support structure in predetermined position relative to said body
structure.
9. The razor as claimed in claim 8 wherein said biasing means is in
engagement with said spring member.
10. A safety razor comprising body structure,
blade support structure disposed in said body structure including a
surface adapted to support a blade and being movable as a unit
relative to said body structure,
biasing means in engagement with said body structure and exerting a
force on said support structure, and
guard structure, said guard structure being movable relative to
said blade support structure to change the blade tangent angle of
the shaving geometry and concurrently moving said blade support
structure against the force of said biasing means to maintain
substantially constant cutting edge exposure.
11. The razor as claimed in claim 10 wherein said guard structure
is mounted for rotational movement to provide a range of blade
tangent angles.
12. The razor as claimed in claim 10 wherein said guard structure
includes a first guard surface forward of said predetermined edge
position and a second guard surface rearward of said predetermined
edge position, said guard surfaces defining said cutting edge
exposure.
13. The razor as claimed in claim 10 wherein said body structure
includes an aperture for receiving a dispenser key and said blade
support structure includes a cam surface engageable with said
injector key for moving blade support structure relative to said
body structure to release a blade positioned on said support
surface.
14. The razor as claimed in claim 10 wherein said blade support
structure is mounted in said body structure to move away from said
guard structure in response to resistance encountered in shaving to
reduce the exposure of the blade edge, thereby increasing the
safety and comfort of the shaving operation.
15. A safety razor comprising body structure,
blade support structure disposed in said body structure including a
surface adapted to supprot a blade and a reference surface and
being movable as a unit relative to said body structure, a spring
member for biasing a blade positioned on said support surface to
urge the rear edge of said blade into engagement with said
reference surface,
biasing means in engagement with said body structure and exerting a
force on said support structure, and
guard structure, said guard structure being movable relative to
said blade support structure to change the blade tangent angle of
the shaving geometry and concurrently moving said blade support
structure against the force of said biasing means to maintain
substantially constant cutting edge exposure.
16. A safety razor comprising body structure having a first
internal bearing portion and a second internal bearing portion
positioned below and to the rear of said first internal bearing
portion,
blade support structure disposed in said body structure including a
surface adapted to support a blade and being movable as a unit
relative to said body structure, said support structure including a
first bearing surface for sliding engagement with said first
bearing portion, and a second bearing surface positioned beneath
and to the rear of said first bearing surface for sliding
engagement with said second bearing portion,
biasing means in engagement with said body structure and exerting
an upward force on said support structure, said biasing means
tending to urge said first bearing surface to slide forwardly
across said first bearing portion, and
guard structure including a guard surface positioned forwardly of
said blade support surface, and a stop surface for limiting the
forward movement of said blade support structure under the
influence of said biasing means and positioning the cutting edge of
a blade supported on said blade support structure in predetermined
position relative to said body structure, said guard surface being
movable relative to said blade support structure to change the
blade tangent angle of the shaving geometry of the shaving system
and concurrently moving said blade support structure to maintain
substantially constant cutting edge exposure, and said blade
support structure being mounted in said body structure to move away
from said guard surface in response to resistance encountered in
shaving to reduce the exposure of the blade edge, thereby
increasing the safety and comfort of the shaving operation.
17. The razor as claimed in claim 16 wherein said guard structure
is mounted for rotational movement and includes guard surfaces
forward and rearward of said predetermined edge position.
18. The razor as claimed in claim 17 wherein said blade support
structure includes a reference surface and further including a
spring member for biasing a blade positioned on said support
surface to urge the rear edge of said blade into engagement with
said reference surface, and said body structure includes an
aperture for receiving a dispenser key and said blade support
structure includes a cam surface engageable with said injector key
for moving blade support structure relative to said body structure
to release the clamping force exerted by said spring member on a
blade positioned on said support surface.
Description
This invention relates to safety razors and more particularly to
arrangements for enhancing the shaving performance of safety
razors.
During a typical shaving operation, a range of conditions are
encountered by the cutting edge of the razor blade. A change in
conditions may be due to a change in the pressure of the blade edge
and razor against the face, as exerted by the user, for example, or
contact by the blade edge with an unusual obstruction on the face,
such as an especially dense patch of beard hair, or a change in
contour of the surface being shaved. It is an object of this
invention to provide a novel and improved safety razor that has a
dynamic response to conditions encountered during shaving.
A further object is to provide a safety razor which automatically
adjusts its shaving geometry during a shaving operation to provide
increased comfort and safety of the shaving operation.
The invention provides in a safety razor the feature of automatic
adjustment of shaving geometry when a change in conditions is
encountered during a shaving operation. More particularly, in one
aspect of the invention, a safety razor is provided which has a
head portion including structure for positioning a razor blade in
shaving position. The blade positioning structure is arranged to
permit the blade cutting edge to move relative to the head portion.
Biasing means are provided for urging the blade towards a position
of normal exposure. A guard member is mounted on the head portion
for movement between first and second positions and is disposed to
engage the blade positioning structure, whereby movement of the
guard member causes movement of the blade cutting edge. Preferably,
the guard member also includes first guard structure forward of and
below the cutting edge and second guard structure to the rear of
and above the cutting edge, the first guard structure including a
surface which so engages the blade positioning structure when the
blade is in the position of normal exposure. It is also preferred
that the blade positioning structure comprise a support unit
including a surface for receiving a razor blade thereupon and
structure generally perpendicular to that surface, the biasing
means engaging this latter structure.
In accordance with another feature, there is provided a safety
razor arrangement in which guard structure is movable relative to
blade support structure to change the blade tangent angle of the
shaving geometry and concurrently moving the blade support
structure to maintain substantially constant cutting edge
exposure.
The relationships of components of a shaving system are
conveniently discussed in terms of certain parameters defined as
follows. The blade tangent angle (BTA) of a cutting edge is the
angle between the plane bisecting the two planes or facets of the
blade that define the edge and the plane through the edge and
tangent to the skin engaging surface (e.g., a guard surface) next
forward of the edge. The exposure (E) of an edge is the distance of
the edge from a plane tangent to both the next forward and the next
rearward skin engaging surfaces. The exposure may be positive or
negative and is reckoned positive when the edge lies on the
skinward side of the doubly tangent plane.
In a preferred embodiment, the guard structure is mounted for
rotational movement although other motions such as a linear guard
structure motion with a camming engagement of the blade support
structure may also be utilized to achieve this desired
cooperation.
In accordance with another feature of the invention a safety razor
has body structure with a first internal bearing portion and a
second internal bearing portion positioned below and to the rear of
the first internal bearing portion, blade support structure
disposed in the body structure including a surface adapted to
support a blade and being movable as a unit relative to the body
structure, the unit including a first bearing surface for
engagement with said first bearing portion, and a second bearing
surface positioned beneath and to the rear of the first bearing
surface for engagement with the second bearing portion, biasing
means in engagement with the body structure and exerting an upward
force on the support structure and tending to urge the first
bearing surface to slide forwardly across the first bearing
portion, and stop structure for limiting the forward movement of
the blade support structure under the influence of the biasing
means and positioning the cutting edge of a blade supported on the
blade support structure in predetermined position relative to the
body structure.
In one particularly preferred embodiment, the invention features a
safety razor comprising a generally hollow body member including
first and second upper internal bearing portions and a lower
internal bearing portion, the upper bearing portions engaging the
blade. Blade positioning structure is provided and arranged to
permit the blade cutting edge to move relative to the body member.
That structure comprises a blade support unit including a surface
for receiving a blade thereupon and elongated structure below that
surface having a bearing surface remote from said blade receiving
surface and engaging said lower internal bearing portion of the
body member; a spring clamp including a first portion which
overlies the blade receiving surface and a second portion which
engages the elongated structure of the support unit, stress within
the clamp operative to exert a clamping force (exerted by the first
portion) upon a blade disposed upon the blade receiving surface;
and spring means disposed to exert upon the clamp second portion a
force generally in the direction of the blade receiving surface of
the support unit, the spring means and the body member bearing
portions cooperating to urge the blade receiving surface to forward
position in which a blade received thereupon has a normal exposure.
Also included is a guard member mounted adjacent the blade cutting
edge for movement between first and second positions and disposed
to engage the blade support unit, whereby movement of the guard
member causes movement of the blade support unit against the
influence of the spring means.
Other objects, features, and advantages of the invention will
appear from the following description of a preferred embodiment
taken together with the attached drawings thereof, in which:
FIG. 1 is a partially broken away perspective view of a partially
disassembled razor constructed according to the present
invention;
FIG. 2 is an exploded view of the head portion of the razor of FIG.
1;
FIGS. 3-5 are sectional views of the head portion of the razor of
FIG. 1 illustrating a change in shaving geometry during a shaving
operation; and
FIGS. 6 and 7 are sectional views analogous to FIGS. 3-5
illustrating the positioning of a used blade within the razor
preparatory to its removal for replacement by a fresh blade.
DESCRIPTION OF PARTICULAR EMBODIMENT
The razor of FIG. 1 includes a grip portion 10 and a head portion
12, the main body of the grip portion 10 and the outer body 11 of
head portion 12 being molded as a single piece of plastic.
The handle is generally hollow and has integral reinforcing ribs 14
extending between handle side panels 13 and back panel 15. A
removable metal cover plate 16 for the open side of the hollow
handle 10 is shown in FIG. 1 in a removed position. The cover 16
has an offset upstanding tab 18 at its lower end which is adapted
to fit into slot 20 provided in integral wedge 21 at the lower end
of handle 10. It also has a pair of notches 22 (only one being
visible in FIG. 1) in the lateral edges of walls 23 which fit over
a pair of lugs 24 (only one being visible in FIG. 1) provided on an
inner surface 38 of the plastic body 11 of the head portion. Upper
portion 25 of plate 16 serves to enclose head portion 12 of the
razor.
The head portion 12 includes a guard member 26 pivotally mounted in
a position that permits the cutting edge of a razor blade 28 to be
disposed within a slot provided in guide member 26 (all as further
described below).
The exploded view of FIG. 2 illustrates in greater detail the head
portion of the razor and the interrelation of its various
components. The blade 28 is retained on support unit 112 by spring
clamp member 114, the upper portion 142 of which overlies the
blade. The sub-unit comprising blade 28, support unit 112, and
clamp 114 is retained within the body 11 of head portion 12 by
retainer member 86. Guard member 26 is mounted for limited rotation
upon projections 104 of retainer member 86 such that the cutting
edge 108 of the blade 28 is exposed within slot 78 of the guard
member. Guard member 26 and retainer member 86 may also be
considered as a subunit to simplify certain aspects of the
description.
The details of the construction of the outer body 11 of head
portion 12 are shown in FIG. 2. Body 11 has a back wall 30, side
walls 32, 34 and top wall 36, all molded from high impact plastic
and integral with handle portion 10. The volume defined by walls
30, 32, 34, and 36 is enclosed at the lateral portions of the lower
side of shaving head 12 by panels 38 each of which merges in a
smooth curve at its opposite ends with a side wall (32 or 34) and a
side panel 13 of handle 10, respectively. Lugs 24 are integral with
walls 38 downwardly and integral with a side wall 32, 34
outwardly.
Top wall 36 merges in a smooth curve (as indicated at 40) with back
wall 30 and has generally planar portion 42 and a downwardly
sloping portion 44 forward of portion 42. Sloping portion 44 has a
recess 46 in its central region and projections 48 of reduced
cross-section area protruding from side regions 50. Projections 48
include lower front edges 49 which acts as bearing edges to
position the blade 28 and influence its motion, as described
below.
Side wall 32 is provided with a forward-opening, elongated, tapered
recess 52 in its upper portion. The lower portion 33 of wall 32 has
a reduced width from that of the wall portion in the vicinity of
recess 52. This width is equal to the width of wall 38. A generally
rectangular, forward-facing projection 54 is provided intermediate
notch 52 and the lower portion 34 of wall 32. Projection 54 has an
arcuate recess 56 at its upper forward corner.
Side wall 34 also has a notch 52 (not visible in FIG. 2) in its
upper portion, a reduced width lower portion 33, and a projection
54 having an arcuate recess 56. In addition, it has a notch 57 in
the reduced width lower portion 33 immediately below projection 54.
The notch 57 permits the insertion of an injector-type blade
changer, as described below.
Reinforcing ribs 58 project inwardly from back wall 30 and are
integral therewith. Each rib 58 is generally aligned with one of
the side panels 13 of handle portion 10. Stops 59 project inwardly
from back wall between ribs 58. Additional reinforcing ribs 58a are
provided between ribs 58 and walls 32 and 34 respectively (only one
rib 58a being visible in FIG. 2).
Support shelves 60 are integral with both back wall 30 and one of
said walls 32, 34. Angled lugs 62, of shorter length than shelves
60, are also integral with back wall 30 and a side wall 32, 34 and
include a vertical leg 64 integral with shelf 60 and a horizontal
leg 66 projecting inwardly from leg 64 over shelf 60.
Structure integral with back wall 30 is provided which includes
edges 65 and 67. Edge 65 lies in the plane of the back edge (not
visible) of notch 57 and edge 67 lies in the plane of front edge 69
of the reduced width lower portion of wall 34.
Back wall 30 is itself recessed in its lower central portion to
provide a surface 68 which is an extension of back panel 15 of
handle portion 10. Stud 70 projects from surface 68 and has a
V-shaped notch 72 in its outer surface.
Guard member 26 includes upper and lower guard structures 74 and
76, respectively, which are uniformly separated throughout the
major portion of their length to provide a slot 78 therebetween.
Slot 78 flares at each end of guard member 26 where guard
structures 74 and 76 are integral with connecting webs 79. End
walls 80 have elongated apertures 82 therein which slope downwardly
to the rear at angle to the horizontal of about 14.degree.. Guard
structure 76 is sharply curved to provide rearwardly facing surface
84.
Blade 28 has a back edge 106 and a sharpened front cutting edge
108. An elongated hole 110, itself having a back edge 111, is
provided in the central portion of the body of blade 28 closer to
edge 106 than edge 108.
Blade positioning structure is provided and comprises support unit
112 and spring clamp member 114. The blade support unit 112
includes planar portion 116 having a width approximately equal to
that of blade 28 and a depth somewhat less than that of blade 28.
Depending wall 118 is integral with, and generally perpendicular
to, portion 116 and includes a downwardly projecting portion 120
having a finger 122 extending still further downwardly and curved
somewhat rearwardly. Finger 122 has a smoothly curved surface 124
on the backside of its lower extremity. Depending wall 118 also
includes integral arm 126 which projects forward beneath left
opening 128 in portion 116 and which serves as a stop for a blade
injector, as described below. Cam structure 130 extends laterally
along wall 118 from approximately the center of wall 118 to a
location under right opening 129. Upward projections 132 of wall
118 bend over openings 128, 129 and are integral with blade overlap
structures 134 which overlie openings 128, 129 and which are
generally parallel to portion 116. Downwardly offset projections
136 having front surfaces 137 protrude from the front edge 138 of
portion 116 near the lateral extremities thereof.
Spring clamp 114 includes inwardly curved back portion 140, top
portion 142, bottom portion 144, and arms 146 which project
forwardly from the side edges of back portion 140. Top portion 142
includes flared lateral areas 148 and a depressed front portion
150. Bottom portion 144 has a centrally located opening 152 and
back portion 140 has a tab portion 154 projecting downwardly below
the level of bottom portion 144. Arms 146 include upwardly facing
curved surfaces 156 provided by outwardly bent over upward
projections 158.
Biasing means 160 comprise a wire spring having upwardly turned
ends 162, sloped arms 164, and depressed central portion 166.
The blade positioning structure is held in place in the body 11 of
head portion 12 by retainer member 86 which has generally flat,
elongated portion 88 having a front edge 90 and is downwardly
curved in the back portion of its central region to provide
downwardly facing back edge 92. Projections 94 extend rearwardly
from the extremity of elongated portion 88 and are generally in the
plane of the portion 88. Each projection 94 widens in its rearmost
portion. Furthermore, each projection 94 includes a centrally
located raised surface 96 which assures a snug fit of projections
94 in the appropriate structure of plastic body 11, as further
described below. Guard member supports 98 are provided at the ends
of retainer member 86. Each support 98 includes a rear portion 100
aligned with portion 88 and a generally oval forward projecting
portion 102 having a centrally located, generally oval, 0.082 inch
long projection 104 projecting 0.020 inch outwardly from the outer
surface thereof. Projection 104 tapers from a width of about 0.040
inch at its forward portion to a width of about 0.0284 inch at its
rear portion. The upper surface of projection 104 slopes downwardly
rearwardly at an angle of 16.degree. from the horizontal and the
lower surface slopes similarly at an angle of 2.degree.. The
combination of sloping upper and lower surfaces achieves the taper
of the projection 104.
The interrelationship of the various components of the assembled
head portion 12 may now be described. Blade 28, support unit 112,
and clamp member 114 may be considered as a single sub-assembly.
Blade 28 rests upon portion 116 of support 112 with rear edge 106
abutting upward projections 132 of wall 118 of the support unit.
With finger 122 inserted through opening 152 of the clamp member
114, top portion 142 of clamp member 114 projects over blade 28 and
portion 116 between structures 132 with depressed front portion 150
engaging edge portion 111 in opening 110 of blade 28. Clamp member
114 is made from a resilient metal and is sized such that the
inwardly curved back portion 140 will be flexed from its relaxed
configuration and top portion 142 will be biased toward portion 116
of support 112 when the clamp member 114 is assembled with the
blade 28 and support unit 112 as just described. This assures that
the blade 28 will be firmly clamped between clamp 114 and support
unit 112 and back edge 106 of blade 28 will be biased firmly
against projections 132 of support unit 112.
The sub-assembly just described is inserted into the plastic body
13 with the rear portions of support unit 112 being disposed
between the top surface of lugs 62 and the underside of top wall
36, rounded surface 124 on finger 122 of the support unit being
disposed in notch 72 of stud 70, and clamp member 114 aligned
between ribs 58. The sub-assembly of guard member 26 and retainer
member 86 is arranged so that lateral projections 104 on retainer
member 86 engage openings 82 in the end walls 80 of guard member
26. The retainer member 86 with guard member 26 attached is
inserted with projections 94 being disposed in the space between
shelves 60 and lugs 62, raised portions 96 assuring firm frictional
retention of member 86 within the plastic body 13. In this position
guard member 26 prevents the sub-assembly of blade member 28 and
support unit 112 described above from being withdrawn from the body
13 since, as the sub-assembly slides to an extreme forward
position, front surfaces 137 of support unit 112 strike the surface
84 of guard member 26.
Spring 160 is disposed with the undersides of upturned ends 162
bearing upon walls 38 and depressed central portion 166 engaging
the lower side of bottom wall 144 of clamp member 114 in front of
downward projection 154 of back wall 140.
The operation of the blade positioning and biasing system may be
described with reference to FIG. 3. The spring means 160 performs a
dual function. Its upward component of force (as viewed in FIG. 3)
presses the blade 28 in the sub-unit composed of the blade 28, the
blade support unit 112, and the clamp member 114 against the lower
forward edges 49 (see FIG. 2) of projections 48 of the upper
portion 36 of the plastic body 11, thereby eliminating undesirable
blade flutter during a shaving operation. The spring 160 also
cooperates with the various limitations on movement which the
remainder of the razor imposes upon the aforementioned sub-unit,
and, in particular, the limitations of the blade bearing on edge 49
just mentioned and the limitation of the notch 72 bearing upon the
smoothly curved surface 124 of support unit 112, provide for a
counter-clockwise biasing of that sub-unit. This biasing,
therefore, tends to urge the cutting edge 108 of blade 28 forward
(left in FIG. 3) to a "normal" position in which projections 136 of
support unit 112 are in contact with surface 84 of guard member
26.
FIGS. 3-5 are transverse sectional views of the head portion of the
razor described above taken along a reference line through the
assembled head portion, which reference line would intersect
support unit 112 along reference line X in FIG. 2. These FIGS.
illustrate the action of the razor mechanism which occurs within
the head portion as the guard member rotates upon encountering
changing shaving conditions.
In FIG. 3 the blade 28 is in its forwardmost position and the guard
member 26 is rotated in its fully "up" (clockwise in FIGS. 3-5)
position. With the blade 28 and guard member 26 in those positions
the exposure of the blade shaving edge 108 beyond a tangent
reference line Y (drawn between the structure above and below the
blade) is a predetermined value (e.g., a small positive value).
In FIG. 4 the guard member 26 has rotated downwardly (i.e.,
counterclockwise) and in so doing causes a retraction of the blade
due to the force exerted by surface 84 of the guard member on
projection 136 of the blade support unit. The amount of rotation
shown in FIG. 4 is approximately one-half the total rotation of
which guard member 26 is capable. This is indicated by the fact
that the back, tapered end of projection 104 is centered within the
wider back portion of opening 82.
In FIG. 5 the guard member 26 has rotated to its extreme downward
or clockwise position with the lower surface of projection 104
engaging the lower surface of opening 82 thereby providing a stop
to prevent further rotation. The blade support unit has been caused
to retract even further against the biasing force of spring
160.
The retraction rate of the blade caused by dynamic movement of the
guard member is regulated to maintain a relatively constant
exposure. Since the rotational center of the guard member does not
coincide with the blade edge, the tangent line Y will swing on an
arc exposing more and more of the blade edge as the guard member
rotates clockwise. The point of contact between projection 136 and
surface 84 is in a predetermined spatial relationship with the
center of rotation of the guard causing the blade edge to retreat
as the tangent line Y rotates and thus maintaining the desired
exposure. Exposure is reduced when the blade retracts in response
to high cutting forces during shaving.
The position of notches 22 with respect to upper portion 25 of
cover plate 16 is chosen such that when notches 22 are engaged with
lugs 24, inner surface 27 of portion 25 is biased against edge 90
of retainer 86 to securely hold the entire assembly of retainer 86,
guard 26, support unit 112, blade 28, and clamp 114 within the head
portion 12. The upper portion 25 is spaced apart from front edge 69
of the lower portion of wall 34. The gap between edge 69 and
portion 25 of the cover plate 16 cooperates with notch 57 to
produce an inverted L-shaped opening in the right side (as viewed
in FIGS. 1 or 2) of the assembled razor. This opening is suitable
for insertion of an arm portion of an "injector" type razor blade
dispenser. Edges 65 and 67 serve as guides for the camming portion
of such a dispenser inserted into the razor head. Cam 130 is
positioned to be engaged by the portion of the inserted dispenser
key into the razor so as to retract blade platform subassembly
moving edge 108 rearwardly from between guard structures 74 and 76.
Surfaces 156 are also engaged by the blade dispenser portion so as
to lower the support unit 112 with lateral projections 139 resting
on the sloping surfaces 99 of the retainer 86 thereby bringing the
blade into alignment with notches 52 to permit removal of the used
blade from support unit 112 and clamp member 114 and insertion of a
fresh blade through notch 52 in wall 34. Projection 126 on support
unit 112 serves as a stop to properly position the inserted key
portion of the blade dispenser.
FIGS. 6 and 7 illustrate how the razor mechanism acts to position
the blade 28 so as to be free from interference from guard member
26 and to be positioned to be aligned with notches 52 upon
insertion of an arm or key portion 200 of an injector-type razor
blade dispenser. FIG. 6 illustrates the arm 200 partially inserted
into the razor, and FIG. 7 illustrates the arm fully inserted into
the razor (i.e., with its remote end abutting stop 126 on blade
support unit 112).
The arm 200 has the general cross-sectional form of an inverted L.
The long vertical side 202 of the L and the long horizontal side
204, after the arm 200 is fully inserted (see FIG. 7) abut the
inner surface of upper portion 25 of plate 16 and surface 92 of
retainer member 86, respectfully. The locations of arm 200 surfaces
206 and 208 with respect to surfaces 202 and 204 are chosen such
that upon full insertion (as in FIG. 7) with surface 206 in contact
with the front surface of cam member 130 and surface 208 in contact
with surfaces 156 on clamp member 114, the sub-unit consisting of
blade 28, blade support 112, and clamp 114 will be so positioned
that the blade 28 is aligned with notches 52 and its tip 108 is
retracted from the slot 78 of guard member 26.
As can be seen from a comparison of FIGS. 6 and 7, the insertion of
arm 200 causes rearward and downward movement of the
above-mentioned sub-unit in response, respectfully, to the force
exerted on cam 130 by surface 206 and upon surfaces 156 by surface
208. This motion produces a stressing of the spring means 160 as is
evident from the greater deformation of spring means 160 in FIG. 7
than in FIG. 6. Furthermore, the internal surfaces of the plastic
body 11 of head portion 12 of the razor are shaped such that when
the clamp 114 contacts that inner surface at the junction 210,
clamp portion 142 is forced forward relative to platform 116
thereby relieving the rearward biasing force exerted on the blade
28.
With the blade 28 thus aligned with notches 52 and spaced from
guard member 26, replacement of a used blade 28 with a fresh blade
may be accomplished in conventional "injector" manner.
As the used blade 28 is forced out through notch 52 by the new
blade, the new blade slides between lower surface of top portion
142 of spring clamp 114 and surface 116 of support 112. The
residual downward clamping force exerted by top portion 142
prevents the new blade from sliding beyond its proper position in
alignment between end walls 80 of guard 26.
When the arm 200 is withdrawn, spring 160 moves the support unit
112 upward and forward sliding on bearing surfaces 49 and 72. As
the support unit 112 moves forward, the clamp 114 is released from
contact with the head portion inner surface and latch portion 150
of clamp 114 engages edge portion 111 of blade 28 and biases the
rear edge 106 against reference surfaces 132 of support 112. The
edge 108 of the blade is properly located with reference to the
surfaces 137 of the support unit 112 and platform subunit surfaces
137 engage guard surfaces 84 to rotate the guard unit to its
initial position of minimum BTA for control of exposure beyond
tangent Y.
Other embodiments will occur to those skilled in the art and are
within the following claims.
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