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 connectors <NUM> each connecting two points of the frame <NUM> in the interior of the frame <NUM>, and elongated blades (not shown) coupled to the connectors <NUM>. Each connector <NUM> includes pegs <NUM> (projections). Each blade is held between adjacent ones of the pegs <NUM>. Patent Literature <NUM> discloses a razor cartridge having a housing comprising a front and a rear. At least one blade is disposed within the housing the blade having a cutting portion with a cutting edge directed towards the front of the housing and a supporting portion positioned at an angle relative to the cutting portion. The supporting portion and cutting portion are formed out of a single sheet of material. At least two supports spaced apart from one another are provided in the housing, each support extending from one of the front or rear of the housing in a direction towards the other of the front or rear of the housing. The supports each comprise a base and at least one protrusion extending from the base. At least one protrusion of each support is configured to contact the supporting portion of the at least one blade. Patent Literature <NUM> discloses a safety razor, comprising a guard member which is disposed in front of a blade tip of a blade, and a cap member is disposed behind the blade tip. The blade is on a shave tangent line connecting the guard member and an apex of the cap member.

The blades of the razor head <NUM> in <FIG> are held by the three connectors <NUM> including a middle portion of the frame <NUM> in the longitudinal direction. The frame <NUM> further includes holders 63a on the inner sides of two short side walls <NUM> that are respectively located at the two ends of the frame <NUM> in the longitudinal direction. The holders 63a hold the blades. Thus, the flow resistance of fluids flowing inside the frame <NUM> tends to increase. If the number of the connectors <NUM> is reduced in order to lower the flow resistance, foreign matter (e.g., beard trimmings) is easily removed. However, the blades are supported at a smaller number of positions. This causes the blades to be easily bent and thus results in other inconveniences. Further, if the blades are supported at a larger number of positions in order to limit the flexing of the blades, the flow resistance of liquids increases so that foreign matter is removed in an unsmooth manner. It is an objective of the present invention to provide a razor head that reduces the flow resistance of fluids flowing on the inner side of the frame and limits the flexing of blades.

A razor head according to an aspect of the present invention includes a frame including two opposing long side walls and two opposing short side walls, an entirety of the frame having a rectangular outer form, connectors each connecting two points of the frame in an interior of the frame, and elongated blades arranged on an inner side of the frame. The blades are coupled to only two of the connectors, the two connectors to which the blades are coupled connecting the two long side walls to each other. In a case where a position in the frame in a longitudinal direction is represented by a percentage, when a middle of the frame in the longitudinal direction is <NUM>% and two ends of the frame in the longitudinal direction that correspond to inner surfaces of the two short side walls are <NUM>%, the two connectors to which the blades are coupled are each arranged in a range from <NUM>% to <NUM>% between the middle and the two ends. Each of the two connectors to which the blades are coupled includes a narrow portion, and the narrow portion is shorter in the longitudinal direction of the frame than other portions of the connector. The narrow portion is a portion where the connectors to which the blades are coupled are connected to the long side walls.

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 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 simply hereinafter 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 is referred to as the upward direction, 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. 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. According to the current disclosure, 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>. Alternatively, 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 connector <NUM>, a second connector <NUM>, and a third connector <NUM>. The first, second, and third connectors <NUM>, <NUM>, <NUM> each extend in the lateral direction to connect 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 connector <NUM> connects the middle portions to each other. The second connector <NUM> and the third connector <NUM> are respectively arranged on opposite sides of the first connector <NUM> to connect the two long side walls <NUM>. That is, multiple (e.g., three) connectors parallel to each other are arranged on the inner side of the frame <NUM>. The second connector <NUM> is located closer to the first end of the frame <NUM> in the longitudinal direction than the first connector <NUM>. The third connector <NUM> is located closer to the second end of the frame <NUM> in the longitudinal direction than the first connector <NUM>.

As shown in <FIG>, lengths P1, P2, P3 of the first, second, and third connectors <NUM>, <NUM>, <NUM> in the longitudinal direction of the long side walls <NUM> correspond to the widths of the first, second, and third connectors <NUM>, <NUM>, <NUM>, respectively. P1 is greater than P2 and P3. When the razor head <NUM> pivots (swings) relative to its grip, the first connector <NUM> is involved in the pivoting (swinging) and is not involved in retaining of the blade <NUM>. Thus, the frame <NUM> does not have to include the first connector <NUM>.

The second connector <NUM> and the third connector <NUM> include narrow portions 24a and 25a, respectively. The narrow portions 24a and 25a are connected to a long side wall <NUM>. The narrow portions 24a and 25a are shorter in the longitudinal direction than the other portions of the second connector <NUM> and the third connector <NUM>. That is, the second connector <NUM> and the third connector <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 connector <NUM> and width P3 of the third connector <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>.

As shown in <FIG>, the second connector <NUM> and the third connector <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 second connector <NUM> and the third connector <NUM> may include the same number of projections <NUM>. The projections <NUM> of each of the second connector <NUM> and the third connector <NUM> may have the same shape.

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

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

The second connector <NUM> and the third connector <NUM> are symmetrical with respect to the first connector <NUM>. Likewise, the projections <NUM> and the leaf springs <NUM> of the second connector <NUM> and the projections <NUM> and the leaf springs <NUM> of the third connector <NUM> are symmetrical with respect to the first connector <NUM>. Thus, the projections <NUM> and the leaf springs <NUM> of the third connector <NUM> will hereinafter be described, and those of the second connector <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 connector <NUM> are located on the same position. As viewed in the lateral direction, the second flat surfaces <NUM> on the third connector <NUM> are located on the same position. In other words, the four first flat surfaces <NUM> on the third connector <NUM> are located on the same position in the longitudinal direction and the four second flat surfaces <NUM> on the third connector <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 connector <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 connector <NUM>.

The leaf springs <NUM> will now be described.

As shown in <FIG> and <FIG>, the third connector <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 connector <NUM> and a distal end protruding in a direction away from the second connector <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 connector <NUM> and the third connector <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 connector <NUM> and a second end in the longitudinal direction retained by the third connector <NUM>. Thus, according to the current disclosure, the two connectors (i.e., second connector <NUM> and the third connector <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 in the body 14a of the blade <NUM> 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 connector <NUM> and the third connector <NUM> will now be described.

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

The arrangement of the second connector <NUM> and the third connector <NUM> is determined from the result of the following simulation.

As shown in <FIG>, 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>%.

As shown in <FIG>, plate members <NUM> each having a width of <NUM> are used in the simulation. The plate members <NUM> are respectively arranged at two positions that are separated from the middle toward the two ends of the blade <NUM> in the longitudinal direction by substantially equal distances. Further, each blade <NUM> is arranged in front of the plate members <NUM>. A load acting in the direction shown by the arrows in <FIG>, that is, a load acting rearward (acting in the thickness direction of the blade <NUM>) is applied to the entire blade <NUM> in the longitudinal direction. Under such a condition, the displacement produced by the flexing of the middle and ends of the blade <NUM> was simulated. When the plate members <NUM> are respectively located at the two ends of the blade <NUM>, a state in which the second connector <NUM> and the third connector <NUM> are arranged at the positions of <NUM>% in the longitudinal direction of the frame <NUM> is reproduced.

More specifically, as shown in <FIG>, when each plate member <NUM> is arranged at the position of <NUM>%, the displacement of the middle of the blade <NUM> is <NUM>% and the displacement of the end of the blade <NUM> is <NUM>%. With reference to the displacements, the displacement percentage of the blade <NUM> was calculated for the case of changing the position of the plate member <NUM> in the longitudinal direction.

As shown in the graph of <FIG>, the simulation result indicates that the displacement percentages of the middle and the ends of the blade <NUM> were limited to <NUM>% or smaller when the second connector <NUM> and the third connector <NUM> were arranged in the range from <NUM>% to <NUM>%. Further, the displacement percentages of the middle and the ends of the blade <NUM> were limited to <NUM>% or smaller when the second connector <NUM> and the third connector <NUM> were arranged in the range from <NUM>% to <NUM>%. Furthermore, the displacement percentages of the middle and the ends of the blade <NUM> were limited to <NUM>% or smaller when the second connector <NUM> and the third connector <NUM> were arranged in the range from <NUM>% to <NUM>%. Thus, it is preferred that the second connector <NUM> and the third connector <NUM> be arranged in the range from <NUM>% to <NUM>% and it is more preferred that the second connector <NUM> and the third connector <NUM> be arranged in the range from <NUM>% to <NUM>%. The arrangement in the range from <NUM>% to <NUM>% refers to a state in which the entire second connector <NUM> and the entire third connector <NUM> are included in the range from <NUM>% to <NUM>%. The same applies to the range from <NUM>% to <NUM>% and the range from <NUM>% to <NUM>%.

The simulation result shown in <FIG> indicates that the displacement of the blade <NUM> is minimized at approximately <NUM>%. When the razor head <NUM> is used, beards are shaved at the middle of the razor head <NUM> more often than at the ends of the razor head <NUM>. Thus, it is preferred that foreign matter (e.g., beard trimmings) be smoothly removed in the periphery of the razor head <NUM>. Accordingly, it is preferred that the second connector <NUM> and the third connector <NUM> to which the blade <NUM> is coupled be located slightly outward (located closer to the ends). For example, it is preferred that the second connector <NUM> and the third connector <NUM> be arranged in the range from <NUM> to <NUM>% (median is <NUM>%).

Arranging the second connector <NUM> and the third connector <NUM> in this manner allows only the two connectors (i.e., second connector <NUM> and the third connector <NUM>) to limit the flexing of the blade <NUM> in a favorable manner and holds the blade <NUM>.

As shown in <FIG>, the arrangement of the second connector <NUM> and the third connector <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 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 P2 of the second connector <NUM> and the width P3 of the third connector <NUM> may each range, for example, from 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 a razor head according to the current disclosure will now be described.

In this case, as compared with when the blades <NUM> are coupled to three or more connectors, the total number of projections <NUM> disposed at the connectors is relatively small. That is, while a larger number of the projections <NUM> is preferred for stably retaining the blades <NUM>, a larger number of the projections <NUM> would increase the flow resistance of fluids flowing inside the frame <NUM>. Setting two connectors to which the projections <NUM> are coupled reduces the flow resistance and stably retains the blades <NUM>.

When the flow resistance of fluids flowing inside the frame <NUM> is small, foreign matter (e.g., beard trimmings, dead skin, or shaving agent) is smoothly discharged from the surface of the razor head <NUM> in direct contact with the skin toward the bottom surface, which is opposite from the skin contact surface. Thus, the razor head in direct contact with the user is kept clean (i.e., hygienic). This is also advantageous to the user. Further, when the two connectors to which the blades <NUM> are coupled are arranged at the positions in the range from <NUM>% to <NUM>% between the middle and the two ends, the flexing of the blades <NUM> is limited in a favorable manner and the blades <NUM> are retained. Thus, the beards are shaved in proper contact with the blades <NUM> without the blade edges escaping. This keeps each blade edge in contact with the skin in a favorable manner and thus continues to provide comfort to the user for a long period of time. Further, the flow resistance of fluids is reduced and the flexing of the blade <NUM> is limited.

(<NUM>) The second connector <NUM> and the third connector <NUM> include the narrow portions 24a and 25a, respectively. This reduces 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 connector <NUM> and the third connector <NUM>. As a result, the additional member is prevented from increasing the flow resistance.

(<NUM>) The narrow portions 24a and 25a are portions where the second connector <NUM> and the third connector <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.

(<NUM>) As the projections <NUM> of the second connector <NUM> are seen in the lateral direction, the first flat surfaces <NUM> are located at the same position and the second flat surfaces <NUM> are located at the same position. The projections <NUM> of the third connector <NUM> are arranged in the same manner.

This structure allows the projections <NUM> to retain the blades <NUM> evenly. More specifically, in the case of using a razor including blades, the blades tend to receive a load at the same position in the longitudinal direction. When the blades are evenly retained, the blades are flexed more evenly. This makes the feel of the shaver on the skin of the user more even and thus provides comfort to the user. Further, the blades are flexed more evenly so that the intervals between the blades are more even. If the intervals between the blades are partially narrow, the narrow parts tend to be clogged by, for example, beard trimmings, dead skin, or shaving agent. By preventing such clogging, the razor head in direct contact with the user is kept clean (i.e., hygienic). This is also advantageous to the user.

(<NUM>) The first flat surface <NUM> of one of adjacent two projections <NUM> in the lateral direction and the second flat surface <NUM> of the other one of the two projections <NUM> are shifted from each other in the longitudinal direction so as not to overlap each other. In this structure, the first flat surface <NUM> and the second flat surface <NUM> that hold each blade <NUM> do not oppose each other. Thus, as compared with a structure in which the first flat surface <NUM> and the second flat surface <NUM> oppose each other, the minimum interval W is relatively large. This limits clogging of foreign matter between adjacent ones of the projections <NUM>. Even if the gap S1 is smaller than a reference value in a range of tolerance, the blade <NUM> is easily inserted into the gap between the flat surfaces.

(<NUM>) In the longitudinal direction of the blade <NUM>, the first flat surface <NUM> and the second flat surface <NUM> of each projection <NUM> are equal to each other. This allows the opposite surfaces of the blade to be held in a substantially even manner.

Further, the minimum interval W is relatively large. This limits clogging of foreign matter between the projections <NUM>. Furthermore, since the minimum interval W is large, a portion where the minimum interval W is provided is relatively large during production of a mold for forming the frame <NUM>. This improves the strength of the mold.

(<NUM>) Each blade <NUM> is held by the first flat surface <NUM> of one of two projections <NUM> and the second flat surface <NUM> of the other one of the two projections <NUM>. Thus, as compared with, for example, a structure in which the blade <NUM> is held by two curved surfaces, the blade <NUM> is held more stably. This keeps the blade edge in contact with the skin in a favorable manner and thus continues to provide comfort to the user for a long period of time. Further, wear in the projections <NUM> caused by shifting of the positions of the blade <NUM> is limited. Furthermore, chattering of the blade <NUM> caused by the wear of the projections <NUM> is limited. Chattering of the blade <NUM> makes the user uncomfortable. Thus, comfort is provided to the user also by limiting the chattering of the blade <NUM>.

(<NUM>) Each projection <NUM> has a horizontal cross-sectional shape of a parallelogram. The third and fourth flat surfaces <NUM>, <NUM> are inclined with respect to the moving direction (lateral direction) of the razor head <NUM>. This reduces the flow resistance of solids or fluids (e.g., beard trimmings, dead skin, or shaving agent) in contact with the third and fourth flat surfaces <NUM>, <NUM> and thus allows the solids or fluids to flow more quickly.

(<NUM>) The space Z is provided 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>. Thus, fluids (e.g., water) easily pass through the spaces Z inside the frame <NUM>. Even if burrs are left, for example, at the body 14a or at the two ends of the blade portion 14b in the longitudinal direction, the spaces Z make the burrs non-interfering. This allows the blade <NUM> to be smoothly inserted into the gap between the flat surfaces. Further, even if 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>.

(<NUM>) Each of the second connector <NUM> and the third connector <NUM> includes the leaf springs <NUM> that protrude in the direction away from the other one of the second connector <NUM> and the third connector <NUM>. Each leaf spring <NUM> supports the corresponding blade <NUM>. This allows the leaf spring <NUM> to support parts in the periphery of the two ends of the blade <NUM> in the longitudinal direction while leaving the 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>. Further, the second connector <NUM> and the third connector <NUM> respectively support parts in the periphery of the two ends of the elongated blade <NUM> and thus further stabilizes the blade <NUM>. Even when, for example, the blade <NUM> moves as the leaf spring <NUM> elastically deforms, the blade <NUM> is supported stably.

A razor head according to the current disclosure be modified as follows. The razor head according to the current disclosure and the following modifications can be combined as long as they remain technically consistent with each other. It is noted however that the scope of protection of the current invention is defined by the appended claims.

One or both of the narrow portions 24a and 25a of the second connector <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 connectors <NUM>, <NUM> in the longitudinal direction or may be located at positions separated from the ends.

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 connector <NUM> and the third connector <NUM> may be changed to, for example, two, three, five, or more.

The frame <NUM> does not have to include the first connector <NUM>. That is, the frame <NUM> may include only connectors that hold the blades <NUM>.

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

The second connector <NUM> and the third connector <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.

Claim 1:
A razor (<NUM>) head, comprising:
a frame (<NUM>) including two opposing long side walls (<NUM>) and two opposing short side walls (<NUM>), an entirety of the frame (<NUM>) having a rectangular outer form;
connectors (<NUM>, <NUM>, <NUM>) each connecting two points of the frame (<NUM>) in an interior of the frame (<NUM>); and
elongated blades (<NUM>) arranged on an inner side of the frame (<NUM>), wherein
the blades (<NUM>) are coupled to only two of the connectors (<NUM>, <NUM>, <NUM>), the two connectors (<NUM>, <NUM>) to which the blades (<NUM>) are coupled connecting the two long side walls (<NUM>) to each other, and
in a case where a position in the frame (<NUM>) in a longitudinal direction is represented by a percentage, when a middle of the frame (<NUM>) in the longitudinal direction is <NUM>% and two ends of the frame (<NUM>) in the longitudinal direction that correspond to inner surfaces of the two short side walls (<NUM>) are <NUM>%, the two connectors (<NUM>, <NUM>) to which the blades (<NUM>) are coupled are each arranged in a range from <NUM>% to <NUM>% between the middle and the two ends,
wherein
each of the two connectors (<NUM>, <NUM>) to which the blades (<NUM>) are coupled includes a narrow portion (24a, 25a), and
the narrow portion (24a, 25a) is shorter in the longitudinal direction of the frame (<NUM>) than other portions of the connector (<NUM>, <NUM>), characterized in that,
the narrow portion (24a, 25a) is a portion where the connectors (<NUM>, <NUM>, <NUM>) to which the blades (<NUM>) are coupled are connected to the long side walls (<NUM>).