Note: Descriptions are shown in the official language in which they were submitted.
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SAFETY RAZORS
This invention relates to safety razors and in particular it refers to a
safety razor blade unit having at least one blade with a cutting edge which is
moved
across the surface of the skin being shaved by means of a handle to which the
blade
unit is attached. The blade unit may be mounted on the handle to enable the
blade
unit to be replaced by a fresh blade unit when required. Replacement blade
units
are also commonly referred to as cartridges. Alternatively, a blade unit may
be
attached permanently to the handle with the intention that the entire razor
should be
discarded when the blade or blades have become dulled. Razor blade units
generally include guard and cap surfaces for respectively contacting the skin
in front
of and behind the blade(s), these surfaces serving important roles in
establishing the
so-called shaving geometry, i.e. the parameters which determine the blade
orientation and position relative to the skin during shaving.
There have been prior proposals to equip a safety razor with a comb-
like structure for contacting the skin in front ol~ a blade edge, which
structure is in
some cases arranged on or to constitute the guard surface, while other
arrangements
include inclusion of the comb structure in a spacer between a pair of tandem
blades.
The comb structures are provided with a view to achieving a balance between
safety
and comfort on the one hand and closeness of shave on the other hand. Examples
of prior art comb structures are described in U.S. Patent 3,004,337, 4,272,885
and
5,359,774, in which it is explained that improved safety and comfort come from
reduced contact between the skin and blade edge.
The prior art blade units having comb structures are equipped with
fixed blades and are not easily adaptable to suit blade units in which blades
are
mounted to be movable under forces experienced during shaving in order to vary
the shaving geometry.
In accordance with the present invention there is provided a safety
razor blade unit comprising a frame with guard and cap surfaces thereon. a
plurality
of blades with substantially parallel blade edges mounted on the frame between
the
guard and cap surfaces, the blades being carried on respective blade supports
for
independent movement within the frame for varying the shaving geometry in
accordance with forces imparted on the blades during shaving, at least one of
the
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blade supports having rigidly connected thereto elements spaced apart along
the
blade carried on said blade support and projecting forwardly of the blade
edge, the
elements having skin contacting portions for contacting the skin immediately
in
front of the blade and substantially tangential to the blade edge.
The blade units having comb structures according to the prior art
compromise closeness in attempting to improve safety and comfort. 1t has been
found that excellent closeness results can be achieved while still benefiting
from
enhanced safety and comfort, with a preferred embodiment of a safety razor
blade
unit according to the invention. In the preferred embodiment the forwardly
projecting elements have upper surface portions which in side elevation extend
rectilinearly to a point spaced from the blade edge by a distance in the range
of
0.10 to 0.30 mm. The projecting elements are preferably integral with the
blade
support, although they can be formed on a member firmly secured to the blade
support. In either case the elements can be easily and conveniently
incorporated in
a blade unit having blades which are movable, and the elements remain
effective
despite the blade movements which occur during shaving. Furthermore, the
elements have skin contacting surfaces which are closely adjacent the blade
edge in
all cases. Due to the upper surface portions, which can be flat or arched,
lying
substantially in a common plane with the blade edge, the elements have a
tendency
to function in similar fashion to skis or runners as they slide over the skin
surface
thereby guiding the blade for effective contact with the skin while deterring
any
tendency for blade displacement in a direction longitudinally of the blade
edge.
In a preferred construction the projecting elements have flat sides and
the lateral edges of the upper surface portions merge smoothly with radiused
or
divergent flank surfaces extending to the flat sides. These features
contribute to the
effectiveness of the elements while ensuring comfort is maintained.
Suitably the width of the elements is in the range of 0.1 to 0.3 mm,
and the width of the upper skin contacting surface portions is not greater
than 0.1
mm, which avoids any tendency for the elements to flatten the hairs against
the skin
surface.
The elements are preferably positioned with a pitch of less than
2 mm, e.g. in the range of 0.5 mm to 1.5, and a pitch of approximately 1.0 mm
is
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especially appropriate.
To ensure a gentle initial contact between the elements and the skin
surface they can be provided with rounded nose portions at their forward ends,
these
nose portions leading smoothly into the upper surface portions.
- S The above and other features of a preferred embodiment of the
invention are described below in more detail reference being made to the
accompanying drawings, in which:
Figure 1 is a partial perspective view of a safety razor blade unit;
Figure 2 is an enlarged perspective view showing part of one blade
and its support;
Figure 3 is an end view of the blade and its support;
Figure 4 is a front view of a part of.the blade support;
Figure 5 shows in perspective a modified blade support;
Figure G is an enlarged perspective view of one of the elements of
the blade support of Fig. 5;
Figure 7 is a plan view of the element shown in Fig. 6;
Figure 8 is a front elevation of the element shown in Fig. 6;
Figure 9 is a side elevation of the element shown in Fig. 6;
Figure 10 shows in perspective another razor blade and support
assembly;
Figure 11 is an enlarged perspective view showing part of the
assembly of Fig. 10; and
Figure 12 is an exploded perspective view of the assembly shown in
Fig. 10.
Illustrated in Figure 1 is a safety razor blade unit or cartridge having
a moulded plastics frame 1 on which guard and cap surfaces are provided and
which
respectively include a strip 2 of elastomeric material with longitudinal fins,
and a
~ strip 3 of lubricating material, both fixedly attached to the frame. Mounted
between
the guard and cap are three parallel blades 4 with forwardly directed cutting
edges
" 30 positioned in series between the guard and cap. Each blade 4 is fixedly
connected
to a blade support 5, and in a manner known per se the ends of the blade
supports
are connected to the frame to enable movement of the blades relative to the
frame
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against the action of springs (not shown) and under forces imparted against
the
blades during shaving.
As shown in greater detail in Figures 2-4, each blade support 5
includes a generally upright beam portion 10 from the upper edge of which
extends
a forwardly and upwardly inclined blade platform 11 against the upper surface
of
which the blade 4 is fixed, such as by spot welding. lJniformly spaced apart
along
the blade platform and projecting forwardly therefrom are integral comb
elements
12 which are perpendicular to the blade edge. The formation of the elements 12
on
the blade support together with their shape, position and dimensions arc the
important novel features of the invention. As shown elements 12 have flat
sides, at
least along the sections which protrude forwardly of the blade edge, and the
elements have flat upper surface portions 14 which are connected to the side
faces
by radiused edges 15. The leading ends of the elements 12 located forwardly of
the
upper surface portions 14 have rounded noses 16 which lead smoothly into the
I S surface portions 14. The root portions 17 of the elements 12 have upper
surfaces
which are inclined more steeply than the blade platform surface in order to
follow
closely the edge facet at the underside of the blade 4, although this is not
essential
and a larger spacing between the underside of the blade and the elements is
acceptable. The rear or trailing ends of the upper surface portions 14 are
closely
adjacent the blade edge, the width of the gap therebetween being several times
less
than the distance A (Figure 3) from the blade edge to the forward or leading
ends
of the surface portions 14. The surface portions 14 of all the elements on the
blade
support lie in a common plane which is tangential to, i.e. contains the edge
of the
blade carried on the support. The distance A is in the range of 0.10 to 0.3
mm,
more especially from 0.15 to 0.2 mm. The width of the elements between their
flat
lateral faces is in the range 0.5 to 1.5 mm, for example about 1.0 mm, and the
elements are positioned at a pitch of I .0 mm.
In use the projecting elements I2 of the blade supports have a
guiding effect influencing the blade unit to move over the skin in a direction
perpendicular to the blade edges, the elements acting in similar manner to
skis or
runners sliding over the skin surface. Thereby enhanced safety and comfort can
be
obtained. At the same time the elements 12 ensure an effective cooperation of
the
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blades with the skin surface leading to excellent shaving results in terms of
closeness.
Illustrated in Figures 5 to 9 is a modified blade support which could
be used with any one or more of the blades in the safety razor blade unit of
' S Figure 1. The modified blade support is the same as that described with
reference
to Figures 2 to 4, except that the shape of the forwardly projecting elements
22 is
different. Instead of having flat upper surlace portions, the elements have
arched
central upper surface portions 24 having a radius of curvature of about 0.07
mm,
the lateral edges of which merge smoothly with divergent flank surfaces 25
which
extend to the flat side faces. As seen in side elevation (Fig. 9) the crests
of the
arched upper surface portions extend rectilinearly to a point 27 whereat these
surface portions merge smoothly with rounded noses 26. '1'hc dimensions of the
elements 22, as far as width and pitch are concerned, may be the salnc as
described
for Figures 2 to 4, and when a blade is mounted on the blade support. the
distance
I S of the point 27 from the blade edge will be the same as the distance A
mentioned
above. In Figures 10 to 12 there is illustrated a razor blade and blade
support
assembly in which instead of being integral with the blade support as in the
embodiments of Figures 1-9, the elements 32 projecting forwardly of the blade
edge
are formed on a separate injection moulded plastics member 30 which is fixed
securely to the blade support 31. As shown, the moulded member 30 has spaced
along its length integral pegs or studs 34 which are inserted through
corresponding
holes 35 provided in the blade support, the protruding free ends of the studs
being
deformed such as by application of heat and pressure so that they are radially
enlarged to the rear of the blade support and' hence fasten the moulded member
to
the blade support. The upper edge of the moulded member is shaped to follow
the
contour of the blade support on the underside of the portion which carries the
blade
36, and the elements 32 project forwardly from this upper edge. The rear end
upper
faces of the member 30 define two surfaces for abutment with the blade support
31
to assist in ensuring accurate alignment of the projecting elements with the
blade
support and hence the cutting edge of the blade 36. The projecting elements 32
may have the same shape and dimensions as the elements 22 of the blade support
described above with reference to Figures 5-9, and they are preferably
positioned in
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relation to the sharpened edge of the blade 36, also as described above in
relation to
the earlier embodiments. The blade and support assembly of Figures 10-12 can
be
used as one or more of the blade and support assemblies in the razor blade
unit of
Figure 1.
While it is apparent that modifications and changes can be made
within the spirit and scope of the present invention, it is our intention,
however,
only to be limited by the appended claims.
