阅读说明：本技术 剃须刀刀片架 (Razor blade holder ) 是由 金动镒 吴省勋 于 2019-06-12 设计创作，主要内容包括：本发明公开了一种剃须刀刀片架,其包括用于容纳多个剃须刀片的刀片壳体,其中,所述多个剃须刀片至少包括第一剃须刀片和第二剃须刀片,所述第一剃须刀片的刀锋部的厚度比所述第二剃须刀片的刀锋部的厚度薄,所述第一剃须刀片具有的第一跨度距离比所述第二剃须刀片具有的第二跨度距离短。(A razor cartridge includes a blade housing for containing a plurality of shaving blades, wherein the plurality of shaving blades includes at least a first shaving blade and a second shaving blade, a blade front of the first shaving blade is thinner than a blade front of the second shaving blade, and the first shaving blade has a first span distance shorter than a second span distance of the second shaving blade.)

1. A shaving razor cartridge comprising a blade housing for receiving a plurality of shaving blades,

wherein the plurality of shaving blades includes at least a first shaving blade and a second shaving blade,

the thickness of the blade edge portion of the first shaving blade is thinner than that of the blade edge portion of the second shaving blade,

the first shaving blade has a first span distance that is shorter than a second span distance that the second shaving blade has.

2. The razor cartridge of claim 1, wherein the second span distance is 0.95mm or greater.

3. The razor cartridge of claim 1, wherein the first span distance is 0.5mm to 0.95 mm.

4. The razor cartridge of claim 1, wherein the second span distance is 0.95mm to 1.6 mm.

5. The razor cartridge of claim 1, wherein the shaving cutting force of the first shaving blades is less than the shaving cutting force of the second shaving blades by more than 5%.

6. The razor cartridge of claim 1, wherein the plurality of shaving blades comprise razor tips and a base portion, the tips not being on an extension of the base portion.

7. The razor cartridge of claim 1, further comprising:

a first contact member disposed in front of the plurality of shaving blades accommodated in the blade housing with reference to a shaving direction; and

a second contact member disposed behind the plurality of shaving blades accommodated in the blade housing with reference to a shaving direction,

and the first razor blade has a protrusion value different from that of the second razor blade with reference to a contact plane tangent to the first contact member and the second contact member.

8. The razor cartridge of claim 1,

the thickness of the first razor blade satisfies a range of 4.7 to 5.7 μm and the thickness of the second razor blade satisfies a range of 5.7 to 6.7 μm at a position of 15 μm from the tip of the razor blade.

9. The razor cartridge of claim 1, further comprising:

a first contact member disposed in front of the plurality of shaving blades accommodated in the blade housing with reference to a shaving direction;

a second contact member disposed behind the plurality of shaving blades accommodated in the blade housing with reference to a shaving direction; and

a third contact member disposed between the first contact member and the second contact member,

wherein at least one of the plurality of shaving blades is arranged on a front area between the first contact member and the third contact member and a rear area between the third contact member and the second contact member, respectively.

Technical Field

The present invention relates to a razor cartridge, and more particularly, to an arrangement structure of shaving blades mounted in the razor cartridge.

Background

Typically, existing wet shavers include a razor cartridge and a razor handle. The razor cartridge can be mounted and dismounted relative to the razor handle so that the user can replace the razor cartridge as desired. In addition, a plurality of shaving blades are arranged on the razor cartridge along the shaving direction.

The shape and size of the razor blades have a great influence on the quality of shaving. Generally, the shaving blades are formed in a shape converging towards the front end (ultimate tip) with a continuous taper. The portion of the razor blade closest to said front end is called a cutting edge (tip edge). If the blade edge is thick and strong, it is not easily worn and has a long life, but the cutting force (cutting resistance) becomes large and the pulling (tangling) and pulling phenomenon are increased, thereby hindering a comfortable shaving operation. Conversely, if the profile of the blade edge is thin, the cutting force becomes small, but with it the risk of breakage or damage and the possibility of skin laceration increase, and the service life also becomes short. In view of this, it is necessary to form cutting edges (cutting edges) of razor blades that take into account cutting forces, shaving comfort and service life in an optimal manner.

In addition, not only the shape or thickness of the shaving blades, but also the arrangement of the shaving blades has a great influence on the quality of shaving. Factors related to the arrangement of the razor blades may prioritize the protrusion value (exposure) of the razor blades and the span (span) distance of the razor blades. First, the protrusion value of the razor blade should be designed to provide clean and excellent shaving comfort and to minimize injuries and cuts. Such a protrusion value is defined by a relative value to the contact plane, which can be distinguished as negative, neutral, positive, and the protrusion value has a considerable influence on the shaving performance.

Factors that affect the shaving performance, in addition to the protrusion value, the span distance of the shaving blades should be considered as an important factor. Generally, a large span length is advantageous in discharging shaving materials such as shaving aids, moisture, and shaving debris (debris), but the size of the razor cartridge becomes large, and skin irritation, scratches, or damage to the razor blade itself is likely to occur during shaving; and when the span length is small, the opposite phenomenon occurs.

In order to provide sufficient shaving performance together with comfort during shaving, not only the shape and thickness of the razor blade but also the span length of the razor blade need to be reflected, and it is particularly necessary to sufficiently consider what correlation the span length of the razor blade should have depending on the shape or thickness of the razor blade. In the conventional razor cartridge, although there are cases where the factors of the shape or thickness of the razor blades and the span length of the razor blades are considered separately, there is no case where the correlation between these two factors is considered, or the correlation gives a comprehensive consideration to the influence of shaving comfort or shaving performance.

[ Prior art documents ]

[ patent document ]

Patent document 1: korean patent laid-open publication No. 2017-0098262 (2017.8.29 publication)

Disclosure of Invention

Technical problem to be solved

The problem to be solved by the present invention is to provide a razor cartridge that allows shaving blades arranged on the razor cartridge to have a suitable span distance according to the shape or thickness of the shaving blades, so that shaving comfort and shaving performance can be improved.

Another problem to be solved by the present invention is to provide a razor cartridge having both thin and thick shaving blades and which can derive a preferred correlation between the thickness, placement and span distance of the individual shaving blades.

The problems of the present invention are not limited to the above-mentioned ones, and other problems not mentioned will be clearly understood by those skilled in the art from the following description.

Technical scheme

In order to solve the above-mentioned problems, a razor cartridge according to an embodiment of the present invention is provided, including a blade housing for accommodating a plurality of razor blades, wherein the plurality of razor blades includes at least a first razor blade and a second razor blade, a blade edge portion of the first razor blade is thinner in thickness than a blade edge portion of the second razor blade, and the first razor blade has a first span distance shorter than a second span distance of the second razor blade.

Advantageous effects

According to the razor cartridge of the present invention, in the razor cartridge, the relatively thin razor blades are arranged at the position where the span distance is smaller than the reference value, and the relatively thick razor blades are arranged at the position where the span distance is larger than the reference value, so that skin damage such as skin irritation, shaving, etc. can be reduced, and simultaneously shaving substances can be smoothly discharged during shaving. Therefore, there is an advantage that shaving comfort and shaving efficiency can be improved as a whole.

Further, according to the razor cartridge of the present invention, by the thick razor blades arranged at the position having a large span distance, the cutting force can be sufficiently ensured, and the life and durability of the razor cartridge can be increased.

Drawings

Fig. 1 is a perspective view of a razor cartridge according to an embodiment of the invention.

Fig. 2 is a longitudinal sectional view of a central portion of the razor cartridge of fig. 1 taken along a shaving direction.

Fig. 3a and 3b are views of more specific shapes of the razor blades shown in fig. 1 or 2.

Fig. 4 is a longitudinal sectional view of a cutting edge formed on a razor blade according to an embodiment of the present invention.

Fig. 5 is a graph showing thickness dimensions at different positions of the blade shown in fig. 4.

Fig. 6 is a view of the razor cartridge of fig. 2 with the retaining clip removed to show the span length of the razor blade.

Fig. 7 is a diagram of an embodiment in which the span distance of the shaving blades gradually increases.

Fig. 8 is a diagram of an embodiment in which the span distance of the razor blade is gradually decreased.

Fig. 9 and 10 are views of an embodiment in which the large span distance and the small span distance of the razor blade are alternately configured.

Fig. 11 is a view when the span distances of all the razor blades are small span distances.

Fig. 12 is a view when the span distances of all the razor blades are large span distances.

Fig. 13 is a cross-sectional view of a razor cartridge according to another embodiment of the invention.

Fig. 14 is a diagram showing the positional relationship of the contact plane of the razor cartridge and the cutting edge between the razor blades.

Detailed Description

Advantages and features of the present invention and methods of accomplishing the same will become apparent with reference to the following detailed description of embodiments taken in conjunction with the accompanying drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, but rather should be construed as broadly as possible for the disclosure to provide a full and complete disclosure of the invention and to fully convey the scope of the invention to those skilled in the art, and the invention is limited only by the scope of the claims. Like reference numerals denote like constituent elements throughout the specification.

Unless otherwise defined, all terms (including technical and scientific terms) used herein may be used in the sense commonly understood by one of ordinary skill in the art to which this invention belongs. Furthermore, unless explicitly defined otherwise, terms defined in commonly used dictionaries are not to be interpreted as ideally or excessively.

The terminology used herein is for the purpose of describing embodiments and is not intended to be limiting of the invention. In this specification, the singular forms include the plural forms unless otherwise specified in the specification. The use of "comprising" and/or "comprising" in this specification does not preclude the presence or addition of one or more other constituent elements other than the stated constituent elements. Hereinafter, embodiments of the present invention are described in detail with reference to the accompanying drawings.

Fig. 1 is a perspective view of a razor cartridge 100 according to an embodiment of the invention.

The plurality of razor blades 10 have a cutting edge (tip edge) at one end portion, and the other end portion can be fitted into a fitting groove provided in the blade housing 8. At this time, the shaving blades 10 are arranged side by side in the shaving direction in one or more numbers.

In order to prevent the razor blade 10 from being detached from the blade housing 8, both side ends of the cutting edge of the razor blade 10 may be fixed to the blade housing 10 by a pair of fixing clips 7a, 7 b. The pair of fixing clips 7a and 7b are wound around both side ends of the razor blade 10, penetrate through-holes formed in the vicinity of both side ends of the blade case 8, and are bent at the lower surface of the blade case 8. In the embodiment of fig. 1, the front legs (front legs) of the fixing clips 7a, 7b penetrate through holes formed in the vicinity of the front end of the blade case 8, and the rear legs (rear legs) of the fixing clips 7a, 7b are wound around (wrap around) the rear end of the blade case 8. However, the present invention is not limited to this, and the front end and the rear end may be wound, or the legs of the fixing clip may be bent under the blade case after passing through the front end through hole and the rear end through hole, respectively.

In addition, the plurality of razor blades 10 disposed on the blade housing 8 are divided by a front protector 2 and a rear cap 4, and the elastic member 1 may be disposed in front of the protector 2 in a direction parallel to the razor blades 10, and the lubricating band 3 may be disposed in rear of the cap 4 in a direction parallel to the razor blades 10. The elastic member 1 makes the body hair of the user rise in a direction substantially perpendicular to the shaving direction, so that the cutting of the razor blade 10 becomes easy, and the lubricating band 3 makes the skin rough after the cutting of the body hair smooth. However, the present invention is not limited to this, and a lubricating tape may be provided in front of the protector 2 in a direction parallel to the razor blades 10, and an elastic member may be provided in rear of the cap 4 in a direction parallel to the razor blades 10. Further, a lubricating band or an elastic member may be provided both in front of the protector 2 and behind the hood 4.

In fig. 1, a situation is shown where the plurality of shaving blades 10 is five. However, the number of shaving blades 10 arranged on the shaving cartridge 100 may be variously modified depending on the shape, thickness, span distance, size of the shaving cartridge, shaving purpose, and the like of the shaving blades. Thus, more or fewer razor blades may be arranged, typically the number of razor blades used in the industry is at least two and at most seven. Thus, the razor cartridge basically includes front shaving blades adjacent to the protector 2 and rear shaving blades adjacent to the cap 4, and may further include additional shaving blades therebetween.

Fig. 2 is a longitudinal sectional view of the central portion of the razor cartridge 100 of fig. 1 taken along the shaving direction. Referring to fig. 2, five shaving blades 10a to 10e are shown inserted into slots (slots) formed between the mounting projections 9a to 9 e. Specifically, a part of the cutting edge or the bent portion in front of the razor blades 10a to 10e is supported by the mounting projections (e.g., the mounting projections 9a for the razor blades 10 a) in front. In addition, the base portions of the shaving blades 10a to 10e are supported between two mounting projections (for example, the mounting projections 9a, 9b for the shaving blade 10 a) located forward and rearward.

In this way, the shaving blades 10a to 10e are supported by the mounting projections while being firmly set in the blade case 8 by the pair of fixing clips 7a, 7b pressing the blade edges downward at both side end portions.

A more specific shape of the razor blade 10 as shown in fig. 1 or fig. 2 is described below with reference to fig. 3a and 3 b.

First, fig. 3a is a side view of an integrated razor blade according to an embodiment of the present invention, referring to fig. 3a, an integrated razor blade 10 may include a base portion 13 to be mounted in a slot (slot) of a blade housing, a blade portion 11 having a cutting edge 15 at a front end side, and a bent portion 12 connecting the base portion 13 and the blade portion 11 and bent forward, and the overall shape and size of the integrated razor blade includes a height h, a depth d, a radius of curvature R, a bent angle α, and the like.

Illustratively, the one-piece type razor blade 10 has a height h of 1.5mm to 5.0mm, a depth d of 0.7mm to 3.0mm, a radius of curvature R of 0.45mm to 0.9mm, and a bending angle α of 90 DEG to 170 deg. the one-piece type razor blade 10 can be manufactured by bending a single body and can be designed to be thick or thin as needed, and here, the blade edge portion 11 is not on an extension line of the base portion 13.

However, without being limited thereto, the shaving blade used in the present invention may also be a bonded blade (bonded blade)40 as shown in fig. 3 b. The joint type blade 40 includes two parts, namely: a metal base portion 43 for mounting into the slot of the blade housing; and a blade portion 41 joined to the metal base portion 43 and having a blade edge 15. The engagement type blade 40 also has a base portion and a bent portion, as with the one-piece type razor blade 10, and has a blade attachment portion for supporting and engaging the blade cutting portion 41. The metal base portion 43 of the joint type blade 40 is thicker than the blade portion 41, and can firmly support the blade portion 41. Here, the blade portion 41 is not on the extension line of the metal base portion 43.

Hereinafter, the razor blade used in the present invention will be described centering on the one-piece razor blade 10 shown in fig. 3a, but it is not limited thereto, and it is obvious that the present invention does not exclude the joint type blade 40, the line type blade or the other shaped blade as shown in fig. 3 b. However, the integral type razor blade 10 or the joint type razor blade 40 is more favorable for shaving and less irritating to the skin than the straight type razor blade, and therefore, the integral type razor blade 10 or the joint type razor blade 40 is more suitable for use.

Fig. 4 is a longitudinal sectional view of the cutting edge 15 formed on the razor blade 10, 40 according to an embodiment of the present invention. The cutting edge 15 may include, in order from the innermost side outwards, a substrate 16, an intermediate coating layer 18 and an outer coating layer 17. Stainless steel is generally used for the base material 16, but other materials may be used. In addition, a hard coating layer may be included on the outside of the base material in order to increase the strength and corrosion resistance of the base material 16 itself. The hard coating layer may be made of a carbonaceous, nitride, oxide or ceramic material such as DLC.

The intermediate coating layer 18 formed between the substrate 16 and the outer coating layer 17 serves to increase the strength of the razor blade 10, 40 or to promote adhesion of the outer coating layer 17 to the substrate 16. Intermediate coating layer 18 may be a carbon, nitride, oxide, ceramic or chromium containing material such as DLC.

Finally, in order to reduce friction, an outer coating layer 17 is formed on the outer surface of the blade edge 15. The outer coating layer 17 is a polymer composition, and may be made of fluorocarbon (Polyfluorocarbon) or Polytetrafluoroethylene (PTFE). In general, PTFE consists of small particles that cause stable dispersion, and is used as an otherwise stable dry lubricant.

Fig. 5 is a graph showing the thickness dimension at different positions of the blade 15 shown in fig. 4. As shown in fig. 5, the location of the tip (origin) of the blade 15, from which the distance (i) in microns (μm) is marked in the longitudinal direction, may be marked with Pi, may be marked as P0. Therefore, in fig. 5, P3, P9, and P15 indicate positions of 3 μm, 9 μm, and 15 μm in the longitudinal direction from the origin, respectively. In addition, the thickness at these respective locations is defined by the dimension of the blade edge 15 in the transverse direction. For example, T15 refers to the lateral dimension (thickness) of the blade 15 at the P15 position.

In general, the physical properties of the razor blade such as shaving performance and strength are greatly affected by the thickness profile of the cutting edge 15, and thus the desired physical properties of the razor blade can be determined by variously designing these thickness profiles.

According to an embodiment of the present invention, the razor blades arranged on the blade housing 8 may be arranged with both relatively thin razor blades and relatively thick razor blades. Here, the thin razor blade means a razor blade having a relatively small thickness dimension at the entire position of the cutting edge 15, and thus having a thin thickness as a whole, being sharp, and having low cutting force (cutting resistance) and durability. Similarly, a thick razor blade refers to a razor blade having a relatively large thickness dimension at the entire location of the cutting edge 15, so that the thickness is thick as a whole, relatively less sharp, and high in cutting force (cutting resistance) and durability.

Preferably, the thickness profile of the respective cutting edges of the thin razor blade and the thick razor blade may be designed as shown in table 1 below.

TABLE 1

	Thick razor blade	Thin razor blade
			T3	1.2～1.6um	1.0～1.5um
T9	3.6～4.4um	3.0～3.8um
			T15	5.7～6.7um	4.7～5.7um

As shown in table 1, the thick razor blade has a larger thickness than the thin razor blade at the entire position of the cutting edge 15 (position substantially equal to or greater than P1).

In this way, the profiles of the thick razor blade and the thin razor blade can be defined as a whole by the thickness dimension at the Pi position, wherein the important points that influence the change in the physical properties of the whole razor blade according to the blade edge thickness are approximately P3, P9, and P15. Thus, by designing the thicknesses at these positions differently, thick and thin razor blades of various sizes can be manufactured.

The profile of the razor blades has a direct influence on the cutting forces. For example, for the razor blades in table 1, the SHCF (%) value of the thin razor blades was shown to be 5% or more smaller, specifically about 9.36% smaller, than that of the thick razor blades. SHCF (Shaving Hair Cutting Force) is an index for evaluating a Cutting Force, and is a value for relatively evaluating a Force (gf) applied when Cutting a single body Hair. It can be seen that the lower the SHCF, the less force is available for cutting. In general, in the SHCF, if the force at the time of cutting is small, it is represented by "-", if the force is large, it is represented by "+", and when the difference between the SHCFs is more than-5% or more, it is judged that the shaving performance is improved. That is, when the force applied during cutting is less than 5% or more, it is judged that the shaving performance is improved. If the originally applied cutting force is 100 units and the subsequently applied cutting force is 94 units, it can be judged that the shaving performance is improved because the subsequently applied cutting force is 6% smaller than the originally applied cutting force.

In this manner, while the shapes and thicknesses of the thin razor blades and the thick razor blades arranged on the razor cartridge 100 first have an influence on the shaving performance, the design of the gap, i.e., the span (span) distance, in which the razor blades are arranged in the shaving direction on the razor cartridge 100 also has a large influence. In particular, it is important to adaptively select an appropriate span length in consideration of the characteristics of the razor blade.

Fig. 6 is a view showing the span distances sa to se of the respective shaving blades with the securing clips 7a, 7b removed from the shaving cartridge shown in fig. 2. Such span distances may be respectively different for a particular shaving blade, and may be defined in terms of the horizontal distance between the cutting edge 15 of the preceding shaving blade and the cutting edge 15 of the current shaving blade. However, since the first shaving blade 10a has no shaving blade in front thereof, it is defined by the distance between the wall of the protector 2 and the associated cutting edge 15.

Generally, a large span length is advantageous in discharging shaving aids, moisture, shaving debris (debris), and the like, but the size of the razor cartridge becomes large, and scratches are likely to occur during shaving; and when the span length is small, the opposite phenomenon occurs. It is therefore important to select a suitable span distance in view of shaving conditions, which also has to be designed in correspondence with the thickness of the razor blade. For example, the span distance of thin razor blades may be designed to be relatively small in order to reduce skin scratches, while the span distance of thick razor blades may be designed to be relatively large in order to improve the discharge performance during shaving. In particular, even if the thick razor blade and the thin razor blade have the same span distance, the space between the thick razor blade and the razor blade in front thereof is relatively narrow due to its size, and it is necessary to further enlarge the span distance. In addition, the thick razor blade is relatively less sharp and has high cutting force (cutting resistance) and durability, and thus is less likely to be worn, and less likely to scratch the skin or cause injury even if the span length is increased. Therefore, thick razor blades are more advantageous than thin razor blades in terms of ensuring a wider span.

The shaving blades 10a to 10e arranged in fig. 6 comprise at least one thin shaving blade and/or at least one thick shaving blade. Preferably, the frontmost razor blade 10a is a thin razor blade and the rearmost razor blade 10e is a thick razor blade. The foremost razor blade 10a is first brought into contact with body hair during shaving and is disposed with a thin razor blade having a small cutting force, and the rearmost razor blade 10e is last brought into contact with body hair and is disposed with a thick razor blade having a relatively large cutting force. This cutting force is a concept similar to the frictional resistance used when cutting body hair as in the aforementioned SHCF. However, this arrangement is only one embodiment of the present invention, and is not limited thereto, and any different arrangement may be made.

In the present invention, a thick razor blade may be defined as a blade thicker than a thin razor blade in the entire area as described in table 1 above, but T15 may be used as a single reference to distinguish the two. Preferably, the T15 for thin razor blades is in the range of 5.2 + -0.5 μm and the T15 for thick razor blades is in the range of 6.2 + -0.5 μm. Thus, the thickness ratio of the thick razor blade to the thin razor blade is approximately 1.0 to 1.5, preferably 1.15 to 1.5, based on T15.

The reason why T15 is used as a reference in this manner is that the cutting force and durability of the blade are most affected by the value of T15, and the portion that is most involved in cutting body hair is the portion of the blade edge 15 that is not more than P15.

At this time, it is preferable to design the span distance of the thick razor blade to be greater than that of the thin razor blade. In general, if the thickness of the blade edge is thin, the cutting force is small (the cutting resistance is small), but the skin is irritated, so that it is necessary to reduce the skin irritation by making the span distance relatively small. Further, if the thickness of the cutting edge is thick, skin irritation is small and durability is high and more load can be borne, so that by making the span length relatively large, not only the life of the razor cartridge can be increased, but also shaving substances can be easily discharged.

More preferably, with reference to a specific reference value (neutral value), it is possible to make the thick razor blade have a large span distance and the thin razor blade have a small span distance. The reference value may be set to various values, but may be selected within a range of 0.8 to 1.1mm, and preferably may be set to 0.95 mm. For example, thin razor blades have a small span distance of less than 0.95mm and thick razor blades have a large span distance of greater than 0.95 mm. When a practical span distance range is considered, the small span distance may be limited to 0.5mm or more, and the large span distance may be limited to less than 1.6 mm.

Thus, the design of the razor cartridge, which takes into account both the thickness and span of the shaving blades, both minimizes skin irritation and adequately ensures shaving performance, while also improving the overall durability and longevity of the razor cartridge.

The numerical relationship can be expressed by the following expressions 1 to 3 by combining the above numerical relationships. First, mathematical formula 1 shows the relationship between the thicknesses of the thick razor blade and the thin razor blade at the position P15. This is a relation determined only by the shape of the razor blade regardless of the span distance.

[ mathematical formula 1]

T15 _B＝(α+1)*T15 _A，0.1＜α＜0.5

Here, T15 _AT15, T15 denoting thin razor blades _BT15 for a thick razor blade.

Further, the relationship between the span length of the thin razor blade and the thickness at the position P15, i.e., T15, can be expressed by the following mathematical formula 2. As can be seen from equation 2, T15 also needs to increase as the span length of the thin razor blade increases.

[ mathematical formula 2]

T15＝2.2*X+3.6，X:span，0.5≤span＜0.95

Here, T15 refers to T15(μm) of the thin razor blade, and x refers to a span length (mm) of the thin razor blade. However, the span has a margin of ± 10% in consideration of a range suitable for actual shaving performance. That is, x may have a range of 0.9-1.1-span. However, due to errors in the razor blade manufacturing process, the value of T15 of an actual product may not always satisfy equation 2 but has a value similar to equation 2.

In addition, the relationship between the span length of the thick razor blade and T15 can be expressed by the following equation 3. As can be seen from equation 3, T15 also needs to increase as the span length of the thick razor blade increases.

[ mathematical formula 3]

T15＝1.5*x+4.3,x：span，0.95≤span＜1.6

Here, T15 refers to T15(μm) of the thick razor blade, and x refers to the span distance (mm) of the thick razor blade. However, the span has a margin of ± 10% in consideration of a range suitable for actual shaving performance. That is, x may have a range of 0.9-1.1-span. However, due to errors in the razor blade manufacturing process, the value of T15 of an actual product may not always satisfy equation 3 but has a value similar to equation 3.

Fig. 7 to 12 below show various embodiments regarding the arrangement of the shaving blades in view of the correlation between the thickness and the span distance of the shaving blades as described above. As mentioned before, the thin razor blades are razor blades with a T15 of 5.2 ± 0.5 μm, and the thick razor blades are razor blades with a T15 of 6.2 ± 0.5 μm.

Wherein fig. 7 is a diagram of an embodiment in which the span distance of the shaving blades gradually increases. Referring to fig. 7, the span distances sa to se of the shaving blades 10a to 10e gradually increase toward the rear shaving blades from the front to the rear of the razor cartridge.

In this arrangement, by the thin razor blade arranged on the front side of the razor cartridge, proper shaving is accomplished with less cutting resistance while reducing skin irritation, while by the thick razor blade arranged on the rear side, sufficient support strength and smooth discharge of shaving substances can be ensured. In particular, after the shallow level shaving is completed by the front side razor blade, the deep level shaving is completed by the rear side razor blade, so that a balanced shaving stroke (stroke) can be provided as a whole.

In fig. 7, the case where three thin razor blades 20 are arranged on the front side and two thick razor blades 30 are arranged on the rear side is exemplified, but not limited thereto, and five razor blades different from each other may be arranged such that the thickness becomes gradually thicker from the front to the rear.

Next, fig. 8 is a diagram of an embodiment in which the span distance of the razor blade is gradually decreased. Referring to fig. 8, the span distance sa to se of the shaving blades 10a to 10e gradually decreases toward the rear side from the front side to the rear side of the razor cartridge.

In this arrangement, sufficient support strength and smooth discharge of shaving substances can be ensured by the razor blades arranged on the front side of the razor cartridge, while appropriate shaving can be accomplished with less cutting resistance while reducing skin irritation by the razor blades arranged on the rear side. In particular, after shaving is completed with a high cutting force by the front side razor blade, clean and smooth shaving can be finally completed by the rear side razor blade.

In fig. 8, the case where three thick razor blades 30 are arranged on the front side and two thin razor blades 20 are arranged on the rear side is exemplified, but it is not limited thereto, and it is of course possible to arrange five razor blades different from each other with thicknesses gradually decreasing from the front to the rear.

Next, fig. 9 and 10 are diagrams of an embodiment in which the large span distance and the small span distance of the razor blade are alternately configured. Referring to fig. 9 and 10, thin shaving blades 20 and thick shaving blades 30 alternate with each other from the front to the rear of the razor cartridge, and the respective span distances also alternate with each other as long span distances and short span distances. Wherein a thin razor blade 20 is arranged in front in fig. 9, whereas a thick razor blade 30 is arranged in front in fig. 10, the two only differences being present here. In either case, however, the span length of the thick razor blade is the large span length and the span length of the thin razor blade is the small span length.

In this way, when the thick razor blades and the thin razor blades are alternately arranged adjacent to each other, the shaving characteristics possessed by the thick razor blades and the shaving performance possessed by the thin razor blades can be complemented with each other, and thus the overall shaving performance can be improved.

Finally, fig. 11 and 12 show the situation when all shaving blades span a small span distance or a large span distance. In which fig. 11 shows a situation in which all shaving blades are thin shaving blades, the span distance of which is a small span distance. In this manner, by the thin razor blade having a small span length, shaving with less cutting resistance can be achieved while reducing skin irritation. Here, the case where the thickness and the span distance of all the thin razor blades are the same is exemplified, but not limited thereto, and the span distances are different when the thicknesses of the thin razor blades are different from each other.

In addition, fig. 12 shows a case where all the razor blades are thick razor blades having a large span distance, in contrast to fig. 11. Thus, by the thick razor blade having a large span length, it is possible to provide a large cutting force and to obtain improved durability and smooth discharge of shaving substances at the time of shaving. Here, the case where the thickness and the span distance of all the thick razor blades are the same is exemplified, but not limited thereto, and the span distances are different when the thicknesses of the thick razor blades are different from each other.

In any of the embodiments of fig. 7 to 12, the five razor blades have a span distance and a thickness (T15) that satisfy at least one numerical range of the foregoing mathematical formulas 1 to 3. The number of the shaving blades is not limited to five only, but may be set to a number of less than five or more than five, of course.

In the above embodiments, the razor cartridge 100 in which the shaving blades 10 are arranged between the front protector 2 and the rear cap 4 is described. However, not limited to this, the razor cartridge 110 may be considered in which an additional protector (an intermediate protector, a third contact member) is further formed between the front protector 2 and the rear cover 4. In this way, when an intermediate guard is further formed at the center of the razor cartridge 110, shaving safety (reduction of injury, laceration, or the like) can be increased and skin adhesion can be improved. In addition, the front area formed between the front protector 2 and the intermediate protector and the rear area formed between the intermediate protector and the rear cap 4 can provide mutually different contact planes, so that a variety of shaving having composite characteristics can be realized.

Fig. 13 is a cross-sectional view of a razor cartridge 110 according to another embodiment of the invention. Here, referring to fig. 13, four razor blades 10a to 10d are arranged on the blade housing 8 with an intermediate guard 5 provided between the two razor blades 10a, 10b in the front region and the two razor blades 10c, 10d in the rear region. As shown, the intermediate protector 5 can be mounted between the mounting bosses in a form similar to the razor blades 10a to 10d, but is not limited thereto, and may be formed in a spacer form integral with the blade housing 8.

According to an embodiment related to fig. 13, the shaving blades 10a, 10b arranged between the front guard 2 and the intermediate guard 5 are relatively thin shaving blades (e.g. 5.2 ± 0.5 μm for T15), and the shaving blades 10c, 10d arranged between the intermediate guard 5 and the rear cap 4 are relatively thick shaving blades (e.g. 6.2 ± 0.5 μm for T15). At this time, the span distance of the thin razor blades 10a, 10b in the front region is relatively small, and the span distance of the thick razor blades 10c, 10d in the rear region is relatively large. For example, the span distances sa, sb of the thin razor blades 10a, 10b are smaller than a reference value (e.g., 0.95mm), while the span distances sc, sd of the thick razor blades 10c, 10d are larger than the reference value.

Accordingly, in actual shaving, first cutting is performed by the thin razor blade, and then second cutting is performed by the thick razor blade. Thus, by the thin razor blades 10a, 10b in the front region, appropriate shaving is accomplished with less cutting resistance while reducing skin irritation, while sufficient cutting force and supporting strength can be secured by the thick razor blades 10c, 10d disposed behind.

According to another embodiment related to fig. 13, a razor blade arranged in at least one of the front region and the rear region comprises: a thin razor blade having a first span distance (e.g., 5.2 ± 0.5 μm for T15), and a thick razor blade having a span distance greater than the first span distance (e.g., 6.2 ± 0.5 μm for T15).

As a more specific example, the shaving blades 10a, 10b of the front area may be arranged in the order of the thin shaving blade and the thick shaving blade (or, in the reverse order), or the shaving blades 10c, 10d of the rear area may be arranged in the order of the thin shaving blade and the thick shaving blade (or, in the reverse order). Of course, the span distance of the thick razor blade should also be arranged to be greater than the span distance of the thin razor blade at this time.

In addition, in the embodiment of fig. 13, the four razor blades have a span distance and a thickness at T15 that also satisfy the numerical range of at least one of the foregoing mathematical formulas 1 to 3. Also, the number of shaving blades is not limited to four. Therefore, the number of the shaving blades of the front area and the number of the shaving blades of the rear area may be equally set to one or three, or may be set to more. Furthermore, the number of shaving blades in the front area and the number of shaving blades in the rear area may be arranged different from each other.

In the above, embodiments were described in which a plurality of razor blades were designed and arranged in consideration of the fact that shaving performance varied according to the correlation between the thickness and the span distance of the razor blades. On this basis, by further considering the correlation between the thickness of the razor blade and the protrusion value (exposure), the shaving performance can be further improved.

Fig. 14 is a diagram showing the positional relationship of the contact plane cp of the razor cartridge and the cutting edge between the respective shaving blades. The contact plane cp is an imaginary plane defined by connecting an upper end of a first contact member located in front of the shaving blade and an upper end of a second contact member located behind the shaving blade. Such a contact plane cp appears as a line in the cross-sectional view shown in fig. 14. The protrusion value of the razor blade is a relative value indicating the position of the blade edge with reference to the contact plane, and can be classified into three values, i.e., positive, neutral, and negative.

At this time, it is preferable to design the protrusion value of the thick razor blade to be larger than that of the thin razor blade. More preferably, on a neutral basis, the thick razor blade may be made to have a positive protrusion value and the thin razor blade may be made to have a negative protrusion value. In general, when the thickness of the blade edge is small, the cutting force is small (the cutting resistance is small), but the skin is irritated, and therefore it is necessary to reduce the skin irritation while maintaining good cutting by making the protrusion value relatively small. Further, if the thickness of the cutting edge is thick, the durability is high and more load can be borne, so that the life of the razor cartridge can be increased by making the protrusion value relatively large.

The embodiments of the present invention have been described above with reference to the drawings, but it should be understood by those skilled in the art that the present invention may be embodied in other specific forms without departing from the technical idea or essential features of the invention. It is therefore to be understood that the above described embodiments are illustrative and not restrictive in all respects.

Also, the dimensions and values disclosed in this specification should not be understood to be strictly limited to the exact numerical values recited. In contrast, unless otherwise specified, each of these numerical values is intended to include the listed values as well as all values on both sides within a functionally equivalent range around the value.