Patent Description:
Patent Literature <NUM> discloses a razor head.

<FIG> shows a typical razor head <NUM>. The razor head <NUM> includes a frame <NUM> with a rectangular outer form, three bridge walls <NUM> each extending between two points of the frame <NUM> in the interior of the frame <NUM>, and elongated blades (not shown) coupled to the bridge walls <NUM>. Each bridge wall <NUM> includes pegs <NUM> (projections). Each blade is held between adjacent ones of the pegs <NUM>. Patent Literature <NUM> which has an earlier priority date but was published after the date of priority of present application discloses a razor head, said razor head comprising a frame and elongated blades being arranged on an inner side of the frame. Two bridge walls each extend between two points of the frame in an interior of the frame, the bridge walls each include projections arranged in an arrangement direction of the blades, wherein each of the blades is held between adjacent ones of the projections of the bridge walls. Each of the projections includes a first flat surface that is in contact with the blade located on one side of the projection in the arrangement direction. A second flat surface is in contact with the blade located on the other side of the projection in the arrangement direction. A third flat surface and a fourth flat surface are inclined with respect to the first flat surface and the second flat surface. The first flat surface is parallel to the second flat surface. The third flat surface is parallel to the fourth flat surface. In each of the bridge walls, the first flat surface and the second flat surface are shifted from each other in a longitudinal direction of the blades so as not to overlap each other as viewed in the arrangement direction. The first flat surfaces are located on the same position as viewed in the arrangement direction and the second flat surfaces are located on the same position as viewed in the arrangement direction.

In the razor head <NUM> of <FIG>, the pegs <NUM> are arranged in a zigzag manner in the longitudinal direction of the bridge walls <NUM>. Adjacent ones of the blades in the arrangement direction of the blades are each held by the pegs <NUM> at a different position.

More specifically, as shown in <FIG>, a first blade <NUM> includes an upper surface 63a in contact with the corresponding peg <NUM> at point A in the longitudinal direction of the blade <NUM> and a lower surface 63b in contact with the corresponding peg <NUM> at point B in the longitudinal direction of the blade <NUM>. A second blade <NUM> adjacent to the first blade <NUM> includes an upper surface 65a in contact with the corresponding peg <NUM> at point B in the longitudinal direction of the blade <NUM> and a lower surface 65b in contact with the corresponding peg <NUM> at point A in the longitudinal direction of the blade <NUM>.

The first and second blades <NUM>, <NUM> are held by the pegs <NUM> at different positions. Thus, the blades may be retained in uneven states. It is an objective of the present invention to provide a razor head capable of retaining blades evenly.

The present invention is defined by the independent claim. Advantageous embodiments are described in the dependent claims, the following description and the drawings. A razor head according to present invention includes a frame, elongated blades arranged on an inner side of the frame, and two bridge walls each extending between two points of the frame in an interior of the frame, the bridge walls each including projections arranged in an arrangement direction of the blades. Each of the blades is held between adjacent ones of the projections of the bridge walls. Each of the projections includes a first flat surface that is in contact with the blade located on one side of the projection in the arrangement direction and a second flat surface that is in contact with the blade located on the other side of the projection in the arrangement direction. In each of the bridge walls, the first flat surface and the second flat surface are shifted from each other in a longitudinal direction of the blades so as not to overlap each other as viewed in the arrangement direction, and the first flat surfaces are located on the same position as viewed in the arrangement direction and the second flat surfaces are located on the same position as viewed in the arrangement direction. Each of the projections has a horizontal cross-sectional shape of a parallelogram.

In the description and claims, the terms "first," "second," and the like are used to distinguish similar components. These terms are not necessarily used to represent a specific sequential or chronological order. In the description and claims, the terms "left," "right," "front," "back," "bottom (surface)," "side (wall)," "upper," "lower," and the like are used to indicate a relative position or structure for illustrative purposes and do not indicate a permanent position or a position when a razor head is used.

A razor head according to an embodiment will now be described.

<FIG> and <FIG> show a razor head <NUM> that is coupled to a holder (not shown) and used as a razor. The razor head <NUM> includes a frame <NUM> with a rectangular outer form, a front member (lower member) <NUM>, and a rear member (upper member) <NUM>.

Unless otherwise specified, the longitudinal direction of the frame <NUM> is hereinafter simply referred to as the longitudinal direction and the lateral direction of the frame <NUM> is hereinafter simply referred to as the lateral direction. The first end of the frame <NUM> in the longitudinal direction is referred to as the left end. The second end of the frame <NUM> in the longitudinal direction is referred to as the right end. The lateral direction also indicates a direction in which the razor head <NUM> moves relative to the skin when the razor head <NUM> is used. The first end of the frame <NUM> in the lateral direction is referred to as the front end. The second end of the frame <NUM> in the lateral direction is referred to as the rear end. When the razor head <NUM> is used, the front end of the razor head <NUM> is located frontward from the rear end in a direction in which the razor head <NUM> travels. Further, the direction that is orthogonal to the longitudinal direction and the lateral direction of the frame <NUM> is referred to as the axial direction or the up-down direction. The direction extending from the sheet of <FIG> toward a person viewing the drawing, and its opposite direction is referred to as the downward direction.

Elongated blades <NUM> extending in the longitudinal direction are arranged on the inner side of the frame <NUM>. The arrangement direction of the blades <NUM> corresponds to the lateral direction (front-rear direction) of the frame <NUM>. For example, five blades <NUM> are arranged in the lateral direction at substantially equal intervals. The number of the blades <NUM> may be changed. For examples, there may be two to four blades <NUM> or may be six or more blades <NUM>.

The front member <NUM> is coupled to the frame <NUM> along the front end of the frame <NUM>. The rear member <NUM> is coupled to the frame <NUM> along the rear end of the frame <NUM>. The front member <NUM> may include a shaving aid or a beard softener containing water-soluble components or function to pull a skin surface or raise beards. The rear member <NUM> may include a shaving aid or a moisturizer for skin that contains water-soluble components.

The razor head <NUM> includes two covers <NUM> that are coupled to two ends of the frame <NUM> in the longitudinal direction, respectively. The two covers <NUM> cover the two ends of each blade <NUM>, respectively. The covers <NUM> restrict the blades <NUM> from moving upward. The razor head <NUM> has a substantially rectangular outer form in plan view in a state where the front member <NUM>, the rear member <NUM>, and the covers <NUM> are coupled to the frame <NUM>. The rectangle includes four chamfered corners and four arcuate sides that are gentler than the four corners.

As shown in <FIG>, the frame <NUM> includes two opposing long side walls <NUM> and two opposing short side walls <NUM>. Thus, the entire frame <NUM> has a rectangular outer form. The thickness direction of each long side wall <NUM> corresponds to the lateral direction of the frame <NUM>. Each long side wall <NUM> includes two hook-shaped projections 21a that protrude outward of the frame <NUM>. The two projections 21a are each arranged on the two ends of the corresponding long side wall <NUM> in the longitudinal direction. Each long side wall <NUM> includes a thick portion 21b located between the two projections 21a. The thick portion 21b is partially increased in thickness.

The front member <NUM> and the rear member <NUM> of the razor head <NUM> each include an engagement piece (not shown) and a contact portion (not shown). When the front member <NUM> and the rear member <NUM> are coupled to the frame <NUM>, each engagement piece engages the corresponding projection 21a and each contact portion contacts the thick portion 21b. In the present embodiment, the two long side walls <NUM> (more specifically, the projections 21a and the thick portions 21b) each have a different shape in correspondence with the front member <NUM> or the rear member <NUM>. In some examples, the two long side walls <NUM> may have the same shape.

The above-described "rectangular outer form" does not indicate only a rectangular outer form in a strict sense. Instead, the above-described "rectangular outer form" includes, for example, an outer form that is entirely substantially rectangular while having a shape including the projections 21a and the thick portions 21b.

The frame <NUM> includes a first bridge wall <NUM>, a second bridge wall <NUM>, and a third bridge wall <NUM>. The first, second, and third bridge walls <NUM>, <NUM>, <NUM> each extend in the lateral direction between two points of the frame <NUM> in the interior of the frame <NUM>. The two long side walls <NUM> each include a middle portion in the longitudinal direction. The first bridge wall <NUM> extends between the middle portions. The second bridge wall <NUM> and the third bridge wall <NUM> extend on opposite sides of the first bridge wall <NUM>, respectively. That is, multiple (e.g., three) bridge walls parallel to each other are arranged on the inner side of the frame <NUM>. The second bridge wall <NUM> is located closer to the first end of the frame <NUM> in the longitudinal direction than the first bridge wall <NUM>. The third bridge wall <NUM> is located closer to the second end of the frame <NUM> in the longitudinal direction than the first bridge wall <NUM>.

As shown in <FIG>, lengths P1, P2, P3 of the first, second, and third bridge walls <NUM>, <NUM>, <NUM> in the longitudinal direction of the long side walls <NUM> correspond to the widths of the first, second, and third bridge walls <NUM>, <NUM>, <NUM>, respectively. P1 is greater than P2 and P3.

The second bridge wall <NUM> and the third bridge wall <NUM> include narrow portions 24a and 25a, respectively. The narrow portions 24a and 25a are connected to the long side walls <NUM>. The narrow portions 24a and 25a are shorter in the longitudinal direction than the other portions of the second bridge wall <NUM> and the third bridge wall <NUM>. That is, the second bridge wall <NUM> and the third bridge wall <NUM> have a narrow width at the narrow portions 24a and 25a, respectively.

The dimensions of the narrow portions 24a and 25a are not particularly limited. For example, the dimensions of the narrow portions 24a and 25a are smaller than width P2 of the second bridge wall <NUM> and width P3 of the third bridge wall <NUM> by <NUM> to <NUM>. In other words, the narrow portions 24a and 25a may be recessed from the other portions by <NUM> to <NUM>.

The narrow portions 24a and 25a are arranged to further reduce the flow resistance of fluids flowing inside the frame <NUM>. Further, when an additional member (e.g., holder) is coupled to the razor head <NUM>, the narrow portions 24a and 25a can be used as the space for coupling the additional member. This prevents the additional member from protruding in the width direction of the second bridge wall <NUM> and the third bridge wall <NUM>. As a result, the additional member is prevented from increasing the flow resistance.

The narrow portions 24a and 25a are portions where the second bridge wall <NUM> and the third bridge wall <NUM> are connected to the long side walls <NUM>. This facilitates the flow of fluids along the inner edges of the long side walls <NUM> and thus further reduces the flow resistance of fluids.

As shown in <FIG>, the second bridge wall <NUM> and the third bridge wall <NUM> each include multiple (e.g., four) projections <NUM> that protrude in the thickness direction (upward direction) of the walls. The four projections <NUM> are each arranged in a row in the lateral direction. The lateral direction of the frame <NUM> corresponds to the longitudinal direction of the second bridge wall <NUM> and the third bridge wall <NUM>. The second bridge wall <NUM> and the third bridge wall <NUM> may include the same number of projections <NUM>. The projections <NUM> of each of the second bridge wall <NUM> and the third bridge wall <NUM> may have the same shape.

The first bridge wall <NUM> does not include the projections <NUM> used to couple the blades <NUM>. That is, the first bridge wall <NUM> does not correspond to a bridge wall used to couple the blades <NUM>, and the second bridge wall <NUM> and the third bridge wall <NUM> each correspond to the bridge wall used to couple the blades <NUM>.

Leaf springs <NUM> protrude from the second bridge wall <NUM> in the longitudinal direction away from the third bridge wall <NUM>. The leaf springs <NUM> are arranged in the lateral direction. Leaf springs <NUM> protrude from the third bridge wall <NUM> in the longitudinal direction away from the second bridge wall <NUM>. The leaf springs <NUM> are arranged in the lateral direction. In other words, the leaf springs <NUM> of the second bridge wall <NUM> protrude toward the first end of the frame <NUM> in the longitudinal direction. The leaf springs <NUM> of the third bridge wall <NUM> protrude toward the second end of the frame <NUM> in the longitudinal direction.

The second bridge wall <NUM> and the third bridge wall <NUM> are symmetrical with respect to the first bridge wall <NUM>. Likewise, the projections <NUM> and the leaf springs <NUM> of the second bridge wall <NUM> and the projections <NUM> and the leaf springs <NUM> of the third bridge wall <NUM> are symmetrical with respect to the first bridge wall <NUM>. Thus, the projections <NUM> and the leaf springs <NUM> of the third bridge wall <NUM> will hereinafter be described, and those of the second bridge wall <NUM> will not be described.

The projections <NUM> will now be described.

<FIG> is a horizontal cross-sectional view of the projections <NUM> that are cut by a cut surface orthogonal to the protruding directions of the projections <NUM>. <FIG> is an enlarged view of the section encircled by the alternate long and short dashed line in <FIG>. The horizontal cross-sectional shape of each projection <NUM> is generally parallelogrammatic with four curved corners. Each projection <NUM> includes first and second flat surfaces <NUM>, <NUM> that extend in the longitudinal direction and third and fourth flat surfaces <NUM>, <NUM> that are inclined with respect to the first and second flat surfaces <NUM>, <NUM>. The first and second flat surfaces <NUM>, <NUM> are a set of opposite sides parallel to each other. The third and fourth flat surfaces <NUM>, <NUM> are another set of opposite sides parallel to each other.

The first and second flat surfaces <NUM>, <NUM> are respectively in contact with the front blade <NUM> (the blade <NUM> on one side in the arrangement direction) and the rear blade <NUM> (the blade <NUM> on the other side in the arrangement direction). The frame <NUM> may include a support protrusion having a distal end surface that is a flat surface parallel to each first flat surface <NUM> or each second flat surface <NUM>. The support protrusion is located in the lateral direction next to the projections <NUM> on the two ends in the arrangement direction. In this case, the blades <NUM> on the two ends in the arrangement direction are supported by the first flat surfaces <NUM> of the projections <NUM> or the second flat surfaces <NUM> of the projections <NUM> and by the distal end surface of the support protrusion.

The first flat surface <NUM> is a front surface of the projection <NUM>. The second flat surface <NUM> is a rear surface of the projection <NUM>. The third flat surface <NUM> is inclined toward the left rear. The fourth flat surface <NUM> is inclined toward the right front.

As viewed in the lateral direction, the first flat surfaces <NUM> on the third bridge wall <NUM> are located on the same position. As viewed in the lateral direction, the second flat surfaces <NUM> on the third bridge wall <NUM> are located on the same position. In other words, the four first flat surfaces <NUM> on the third bridge wall <NUM> are located on the same position in the longitudinal direction and the four second flat surfaces <NUM> on the third bridge wall <NUM> are located on the same position in the longitudinal direction.

There is a gap S1 between the first flat surface <NUM> and the second flat surface <NUM> that hold each blade <NUM> (hereinafter also referred to as the gap between flat surfaces). Each blade <NUM> is inserted into the gap S1 so that the corresponding two projections <NUM> hold the blade <NUM>. This causes the blade <NUM> to be coupled to the third bridge wall <NUM>.

The term "hold" does not only indicate a state in which two projections <NUM> hold the blade <NUM> so as to be immovable in the axial direction, but also indicate a state in which two projections <NUM> hold the blade <NUM> so as to be slidable in the axial direction. For example, during use of the razor, the pressure produced by the blade <NUM> pressing the skin may cause the blade <NUM> to slide in the axial direction.

The gap S1 may be changed in correspondence with the thickness of the blade <NUM>. For example, the gap S1 may range from <NUM> to <NUM> or may range from <NUM> to <NUM>. When the gap S1 falls within these value ranges, the blade <NUM> having a thickness of approximately <NUM> to <NUM> is easily inserted into the gap S1 and easily held by the projections <NUM>.

Length T1 of the first flat surface <NUM> in the longitudinal direction is equal to length T2 of the second flat surface <NUM> in the longitudinal direction. The first flat surface <NUM> and the second flat surface <NUM> that are in contact with each blade <NUM> are shifted from each other in the longitudinal direction so as not to overlap each other as viewed in the lateral direction. In other words, the first flat surface <NUM> and the second flat surface <NUM> of each projection <NUM> are shifted from each other in the longitudinal direction so as not to overlap each other as viewed in the lateral direction. Thus, the first flat surface <NUM> and the second flat surface <NUM> that hold each blade <NUM> do not oppose each other in a state where the blade <NUM> is removed.

Length T1 of the first flat surface <NUM> and length T2 of the second flat surface <NUM> may be changed. For example, T1 and T2 may range from <NUM> to <NUM> or may range from <NUM> to <NUM>. Length T1 may be equal to or different from length T2.

As shown in <FIG>, since each first flat surface <NUM> and the corresponding second flat surface <NUM> are shifted from each other so as not to overlap each other in the longitudinal direction, a minimum interval W between adjacent ones of the projections <NUM> in the lateral direction (hereinafter referred to as the minimum interval between projections) is greater than the gap S1.

<FIG> shows a separation distance U between the second flat surface <NUM> of one of adjacent two projections <NUM> and the first flat surface <NUM> of the other projection <NUM> in the longitudinal direction (hereinafter also referred to as the separation distance between two flat surfaces). The separation distance U may be changed. For example, the separation distance U may range from <NUM> to <NUM> or may range from <NUM> to <NUM>. The separation distance U falling within these value ranges shifts the first flat surface <NUM> and the second flat surface <NUM> from each other so as not overlap each other in the longitudinal direction and relatively reduces width P3 of the third bridge wall <NUM>.

The leaf springs <NUM> will now be described.

As shown in <FIG> and <FIG>, the third bridge wall <NUM> includes five leaf springs <NUM>. Each of the leaf springs <NUM> is a plate member extending in the longitudinal direction. The leaf spring <NUM> includes a basal end connected to the third bridge wall <NUM> and a distal end protruding in a direction away from the second bridge wall <NUM>. More specifically, the distal end of the leaf spring <NUM> protrudes upward as the distal end becomes farther from the basal end of the leaf spring <NUM>. Thus, the leaf spring <NUM> is inclined with respect to the longitudinal direction. The distal end of the leaf spring <NUM> is a free end. This allows the leaf spring <NUM> to be elastically deformable in the axial direction.

When the frame <NUM> is seen from above, each leaf spring <NUM> is slightly inclined such that its distal end is closer to the second end in the lateral direction than its basal end. In other words, the direction in which the leaf spring <NUM> extends is slightly inclined with respect to the longitudinal direction such that the distal end is located on the rear side of the basal end.

The distal end of each leaf spring <NUM> includes a protrusion <NUM> that protrudes upward. As described below, the protrusion <NUM> is a support that supports the blade <NUM>.

The mechanism of the frame <NUM> retaining the blade <NUM> will now be described.

Referring to <FIG>, each of the second bridge wall <NUM> and the third bridge wall <NUM> retains the blades <NUM> with four projections <NUM> arranged in the lateral direction. Each blade <NUM> is inserted into the gap between the flat surfaces of adjacent ones of the projections <NUM> in the lateral direction. Each blade <NUM> includes a first end in the longitudinal direction retained by the second bridge wall <NUM> and a second end in the longitudinal direction retained by the third bridge wall <NUM>. Thus, in the present embodiment, the two bridge walls (i.e., second bridge wall <NUM> and the third bridge wall <NUM>) retain the blades <NUM>. <FIG> show the frame <NUM> to which only one blade <NUM> is coupled.

As shown in <FIG>, the blade <NUM> includes a plate-shaped body 14a held by the projections <NUM> and a blade portion 14b joined to the upper edge of the body 14a. The body 14a includes a bent portion (curved portion) 14c that is bent frontward. The blade portion 14b is joined to the bent portion 14c.

As shown in <FIG>, when the blade <NUM> is inserted into the gap between the flat surfaces, a lower surface P of the bent portion 14c is in contact with the protrusion <NUM> of the leaf spring <NUM>. In other words, the blade <NUM> is supported by the protrusion <NUM> of the leaf spring <NUM>.

As shown in <FIG>, each projection <NUM> includes a distal end surface 30a that is a flat surface inclined with respect to the axial direction. The distal end surface 30a is substantially parallel to a lower surface of the blade portion 14b. The space between the lower surface P of the bent portion 14c and the distal end surface 30a of the projection <NUM> includes a gap S2. The blade <NUM> is permitted to move in the range of the gap S2 in the axial direction as the leaf spring <NUM> elastically deforms.

Since the distal end of each leaf spring <NUM> is slightly inclined rearward when the frame <NUM> is seen from above, the blade <NUM> supported by the leaf spring <NUM> is slightly biased toward the projection <NUM> located on the rear side of the blade <NUM>. This allows the blade <NUM> to be retained more stably.

The material of the razor head <NUM> is not particularly limited. The razor head <NUM> made of resin (plastic) is excellent in moldability. Examples of the resin used as the material of the razor head <NUM> include ABS, polypropylene, polystyrene, polyacetal, and nylon.

The material of each blade <NUM> is not particularly limited. For example, the blade <NUM> may be made of metal, ceramics, or resin. Examples of the metal used as the material of the blade <NUM> include stainless steel and titanium. Examples of the ceramics used as the material of the blade <NUM> include zirconia, aluminum oxide, and silicon nitride. The resin used as the material of the blade <NUM> includes the same resin of the razor head <NUM>.

The arrangement of the second bridge wall <NUM> and the third bridge wall <NUM> will now be described.

As shown in <FIG>, the second bridge wall <NUM> and the third bridge wall <NUM> are located at positions excluding the middle portion and the two ends of the frame <NUM> in the longitudinal direction. In other words, the second bridge wall <NUM> and the third bridge wall <NUM> are located at positions separated from the first bridge wall <NUM>, which is located at the middle of the frame <NUM> in the longitudinal direction, and the two short side walls <NUM>.

When the position in the frame <NUM> in the longitudinal direction is represented by a percentage, the position of the middle of the frame <NUM> in the longitudinal direction is <NUM>% and the positions of the two ends of the frame <NUM> in the longitudinal direction (more specifically, the inner surfaces of the two short side walls <NUM>) are <NUM>%. In this case, the second bridge wall <NUM> and the third bridge wall <NUM> may be arranged in a predetermined range between the two ends and the middle. More specifically, the second bridge wall <NUM> and the third bridge wall <NUM> may be arranged in a range from <NUM>% to <NUM>% or may be arranged in a range from <NUM>% to <NUM>%. In this case, it is preferred that the second bridge wall <NUM> and the third bridge wall <NUM> be in the range from <NUM>% to <NUM>% or in the range from <NUM>% to <NUM>%.

In this case, only the two bridge walls, namely, the second bridge wall <NUM> and the third bridge wall <NUM> hold the blade <NUM> while limiting flexing of the blade <NUM> in a favorable manner.

As shown in <FIG>, the arrangement of the second bridge wall <NUM> and the third bridge wall <NUM> produces a space Z between each of the two ends of the blade <NUM> in the longitudinal direction and the corresponding one of the two short side walls <NUM>. That is, the two ends of the blade <NUM> in the longitudinal direction are separated from the frame <NUM>. Thus, as compared with when the two ends of the blade <NUM> in the longitudinal direction are respectively in contact with the two short side walls <NUM>, the spaces Z through which fluids flow inside the frame <NUM> are wider. Even in a case where burrs are left at the body 14a or at the two ends of the blade portion 14b in the longitudinal direction, the spaces Z allow the blade <NUM> to be smoothly inserted into the gap between the flat surfaces without being interfered by the burrs. Further, even in a case where the blade <NUM> moves in the axial direction as the leaf spring <NUM> elastically deforms, the blade <NUM> is prevented from contacting the inner surface of the frame <NUM>.

Referring to <FIG>, the entire width of the razor head <NUM> (the length of the razor head <NUM> from the first end to the second end in the longitudinal direction) may be changed. For example, the entire width may range from approximately <NUM> to <NUM> and may be about <NUM>. In correspondence with the dimension of the entire width of the razor head <NUM>, the other dimensions may be enlarged or reduced at the same ratio (in a similar shape) and the ratio may be changed.

The length of the razor head <NUM> in the lateral direction (the length of the frame <NUM> in the lateral direction excluding the projections 21a and the thick portion 21b) may be changed. For example, the length of the razor head <NUM> in the lateral direction may range, for example, from approximately <NUM> to <NUM> and may be about <NUM>.

Width P1 of the first bridge wall <NUM> may range, for example, from approximately <NUM> to <NUM> and may be about <NUM>. The arrangement of the first bridge wall <NUM> increases the rigidity of the razor head <NUM>.

Width P2 of the second bridge wall <NUM> and the width P3 of the third bridge wall <NUM> may each range from, for example, approximately <NUM> to <NUM> and may be about <NUM>. Widths P2 and P3 may each be less than or equal to <NUM>% of the entire width of the razor head <NUM>. This allows fluids (e.g., beard trimmings, dead skin, or water containing shaving agent) to be smoothly discharged from the surface of the razor head <NUM> in contact with the skin (upper surface) toward the opposite surface (bottom surface).

The operation and advantages of the present embodiment will now be described.

The present embodiment may be modified as follows. The present embodiment and the following modifications can be combined as long as they remain technically consistent with each other.

As viewed in the lateral direction, the first flat surfaces <NUM> and the second flat surfaces <NUM> arranged in each bridge wall may partially overlap each other in the longitudinal direction. Even in this case, if the gap S1 is smaller than a reference value in a range of tolerance, each blade <NUM> is easily inserted into the gap between the flat surfaces by reducing the regions where the first flat surfaces <NUM> oppose the second flat surfaces <NUM>.

The horizontal cross-sectional shape of each projection <NUM> may be changed. For example, the inclining direction of the third and fourth flat surfaces <NUM>, <NUM> of each projection <NUM> may be reversed such that the second flat surface <NUM> of each projection <NUM> is closer to the middle of the frame <NUM> in the longitudinal direction than the first flat surface <NUM>.

The horizontal cross-sectional shape of each projection <NUM> does not have to be parallelogrammatic. For example, the third flat surface <NUM> and the fourth flat surface <NUM> of each projection <NUM> do not have to be parallel to each other.

The third flat surface <NUM> and the fourth flat surface <NUM> of each projection <NUM> may be changed to curved surfaces recessed such that the middle portions of the curved surfaces become close to each other. In this case, since each projection <NUM> is relatively thin, the frame <NUM> is reduced in weight.

The third flat surface <NUM> and the fourth flat surface <NUM> of each projection <NUM> may be changed to curved surfaces bulged such that the middle portions of the curved surfaces are separated from each other. This facilitates the production of a mold. Further, since each projection <NUM> is relatively thick, the mechanical strength of the frame <NUM> improves.

In the third flat surface <NUM> and the fourth flat surface <NUM> of each projection <NUM>, one of the surfaces may be a curved surface with a recessed middle portion and the other surface may be a curved surface with a bulged middle portion.

The two ends of the blades <NUM> in the longitudinal direction may be in contact with the two short side walls <NUM>, respectively, Further, the two short side walls <NUM> may retain the two ends of the blades <NUM> in the longitudinal direction, respectively. Thus, the spaces Z do not have to be provided.

The number of the projections <NUM> of each of the second bridge wall <NUM> and the third bridge wall <NUM> may be changed to, for example, two, three, five, or more.

The frame <NUM> does not need to include the first bridge wall <NUM>. Alternatively, the frame <NUM> may include another bridge wall in addition to the first bridge wall <NUM>, the second bridge wall <NUM>, and the third bridge wall <NUM>.

In the same manner as the second bridge wall <NUM> and the third bridge wall <NUM>, the first bridge wall <NUM> may include projections <NUM>.

Each of the second bridge wall <NUM> and the third bridge wall <NUM> may include leaf springs <NUM> that protrude in a direction closer to the other one of the second and third bridge walls <NUM> and <NUM>.

The second bridge wall <NUM> and the third bridge wall <NUM> do not have to include the leaf springs <NUM>. That is, the blades <NUM> may be fixed such that the blades <NUM> are immovable in the axial direction.

Each blade <NUM> may be an undivided component in which the body 14a and the blade portion 14b are integrally molded.

One or both of the narrow portions 24a and 25a of the second bridge wall <NUM> and the third bridge wall <NUM> may be omitted.

The narrow portions 24a and 25a do not have to be located at the positions of the above-described embodiment. For example, the narrow portions 24a and 25a may be located at the two ends of the second and third bridge walls <NUM>, <NUM> in the longitudinal direction or may be located at positions separated from the ends.

Claim 1:
A razor head (<NUM>), comprising:
a frame (<NUM>);
elongated blades (<NUM>) arranged on an inner side of the frame (<NUM>); and
two bridge walls (<NUM>, <NUM>) each extending between two points of the frame (<NUM>) in an interior of the frame (<NUM>), the bridge walls (<NUM>, <NUM>) each including projections (<NUM>) arranged in an arrangement direction of the blades (<NUM>), wherein
each of the blades (<NUM>) is held between adjacent ones of the projections (<NUM>) of the bridge walls (<NUM>, <NUM>), characterised in that:
each projection (<NUM>) has a horizontal cross-sectional shape of a parallelogram, wherein
each of the projections (<NUM>) includes:
a first flat surface (<NUM>) that is in contact with the blade (<NUM>) located on one side of the projection (<NUM>) in the arrangement direction;
a second flat surface (<NUM>) that is in contact with the blade (<NUM>) located on the other side of the projection (<NUM>) in the arrangement direction; and
a third flat surface (<NUM>) and a fourth flat surface (<NUM>) that are inclined with respect to the first flat surface (<NUM>) and the second flat surface (<NUM>),
the first flat surface (<NUM>) is parallel to the second flat surface (<NUM>),
the third flat surface (<NUM>) is parallel to the fourth flat surface (<NUM>),
in each of the bridge walls (<NUM>, <NUM>),
the first flat surface (<NUM>) and the second flat surface (<NUM>) are shifted from each other in a longitudinal direction of the blades (<NUM>) so as not to overlap each other as viewed in the arrangement direction, and
the first flat surfaces (<NUM>) are located on the same position as viewed in the arrangement direction and the second flat surfaces are located on the same position as viewed in the arrangement direction.