RAZOR CARTRIDGE

Abstract

A subassembly for a shaving razor cartridge with a base having a front wall with a top surface and a rear wall with a top surface. At least one blade is mounted to the base between the front wall and the rear wall. The at least one blade has a cutting edge positioned at least 0.5 mm below a plane tangent to the top surface of the front wall and the top surface of the rear wall.

Claims

1. a base having a front wall with a top surface; a cage fixed to the base, the cage having an upper skin contacting surface with a plurality of ribs defining a plurality of open slots and a front face generally transverse to the upper skin contacting surface, the front face having a lower surface interconnecting a plurality of ribs that define a plurality of open slots extending into the front face and are communication with the open slots of the upper skin contacting surface; and at least one blade mounted to the base, the blade having a cutting edge positioned below the upper skin contacting surface and immediately behind the front wall, wherein the lower surface of the front face is positioned a vertical distance below the cutting edge.

2. The shaving razor cartridge of claim 1 wherein the lower surface is positioned a vertical distance of at least 0.5 mm below the cutting edge.

3. The shaving razor cartridge of claim 2 wherein the vertical distance is about 0.5 mm to about 3 mm below the cutting edge.

4. The shaving razor cartridge of claim 1 wherein the top surface of the front wall is positioned a vertical distance of at least 0.75 mm below the cutting edge.

5. The shaving razor cartridge of claim 1 wherein the upper skin contacting surface and the front face intersect to form a radius of about 0.1 mm to about 1.0 mm.

6. The shaving razor cartridge of claim 1 wherein at least two blades are mounted to the base each having respective immediately adjacent cutting edges are spaced apart by a distance greater than 1.75 mm.

7. The shaving razor cartridge of claim 1 wherein the ribs have a height of about 0.5 mm to about 5 mm and are spaced apart by about 0.25 mm to about 5 mm.

8. The shaving razor cartridge of claim 1 wherein the upper skin contacting surface and the front face intersect at an exterior angle of about 45 degrees to about 85 degrees.

9. The shaving razor cartridge of claim 1 wherein a gap extending from the cutting edge to a front interior face opposing the front face is 0.5 mm to 3.0 mm.

10. A sub-assembly for a shaving razor cartridge comprising: a base having a front wall having a top surface and a rear wall with a top surface; a plane tangent to the top surface of the front wall and a top surface the rear wall; a plurality of blades mounted to the base, each of the blades having a cutting edge, the cutting edges defining a cutting plane, wherein the top surface of the front wall is at least 0.5 mm below the cutting plane.

11. The sub-assembly of claim 10 wherein the top surface of the front wall positioned at least 0.5 mm below the cutting plane has a length of about 17 mm to about 35 mm.

12. The sub-assembly of claim 10 wherein the top surface of the front wall is less than 5 mm below the cutting plane.

13. The sub-assembly of claim 10 wherein one or more of the cutting edges are positioned a distance below the plane tangent to the top surface of the plane tangent to the top surface of the front wall and the top surface of the rear wall.

14. The sub-assembly of claim 10 wherein a distance between the one or more of the cutting edges and the plane tangent to the top surface of the front wall and the top surface of the rear wall is greater closest to the front wall and the least closest to the rear wall.

15. The sub-assembly of claim 10 wherein a distance between a first pair of immediately adjacent cutting edges closest to the front wall is about 1.8 mm to about 2.0 mm.

16. The sub-assembly of claim 10 wherein a distance between second pair of immediately adjacent cutting edges closest to the rear wall is about 1.8 mm to about 2.0 mm.

17. The sub-assembly of claim 15 wherein a distance between second pair of immediately adjacent cutting edges closest to the rear wall is about 1.8 mm to about 2.0 mm.

18. The sub-assembly of claim 10 wherein a distance between a first pair of immediately adjacent cutting edges closest to the front wall is about 2.0 mm to about 2.5 mm.

19. The sub-assembly of claim 16 wherein a distance between a first pair of immediately adjacent cutting edges closest to the front wall is about 2.0 mm to about 2.5 mm.

20. The sub-assembly of claim 10 wherein a distance between a second pair of immediately adjacent cutting edges closest to the rear wall is about 2.0 mm to about 2.5 mm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Other features and advantages of the present invention, as well as the invention itself, can be more fully understood from the following description of the various embodiments, when read together with the accompanying drawings, in which:

[0008] FIG. 1A is a front perspective view of a shaving razor cartridge according to one possible embodiment of the present invention.

[0009] FIG. 1B is rear perspective view of the shaving razor cartridge of FIG. 1A.

[0010] FIG. 2 is an assembly view of the razor cartridge of FIGS. 1A and 1B.

[0011] FIG. 3 is a perspective view of a subassembly of the razor cartridge of FIGS. 1A and 1B.

[0012] FIG. 4 is a cross section view of the subassembly, taken generally along the line 4-4 of FIG. 3.

[0013] FIG. 5 is a cross section view of the razor cartridge, taken generally along the line 5-5 of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

[0014] Referring to FIGS. 1A and 1B, front and rear perspective views of a shaving razor cartridge 10 are shown, respetively. The shaving razor cartridge 10 may be mounted to a handle (not shown). The shaving razor cartridge 10 may be removable or permanently mounted to the handle. For example, the shaving razor cartridge 10 may be detachably mounted on a handle to enable the shaving razor cartridge 10 to be replaced by a fresh shaving razor cartridge 10 when the blade sharpness has diminished to an unsatisfactory level, or it may be attached permanently to the handle with the intention that the entire razor be discarded when the blade or blades have become dulled. The shaving razor cartridge 10 may include a housing 12. The housing 12 may be molded out of a polymeric material or manufactured from other materials, such as metal. The housing 12 may have an upper skin contacting surface 14 and a front face 16 that is transverse to the upper skin contacting surface 14. The upper skin contacting surface 14 may define a plurality of open slots 18 that are in communication with a plurality of corresponding open slots 20 defined by the front face 16. The open slots 18 may extend all the way to a rear face 40 (FIG. 1B) The open slots 20 may be defined and interconnected by a lower surface 21 of the front face. Accordingly, when hairs contact the front face 16, they are directed immediately to the open slots 20 (i.e., the open slots 20 extend into the front face 16). The open slots 18 and 20 may be separated by corresponding ribs 22. The ribs 22 may extend continuously along the upper skin contacting surface 14 and down the front face 16. Accordingly, the front face may be defined by a plurality of ribs 22 and the lower surface 21 to form the open slots 20. The ribs may have a width w1 of about 0.25 mm to about 5 mm and preferably about 0.4 mm to about 1 mm. The ribs 22 may be spaced apart (i.e., width of the slots 18 and 20) by about 0.25 mm to about 5.0 mm and preferably about 0.7 mm to about 0.8 mm. If the spacing between adjacent ribs is too great, the blades may shave the philtrum (the vertical indentation in the middle area of the upper lip) rather than cutting the hair to length (e.g., the philthrum may sag between the ribs 22). In certain embodiments, the width w1 may less than the distance between the ribs 22. As will be described in greater detail below, a ratio of the width to height of the ribs 22 should be sufficient to prevent the ribs 22 from breaking or deforming during use. Furthermore, the spacing of the ribs 22 (i.e., slot width) and the width of the ribs 22 may impact the efficiency of the blades to cut hair. For example, the width of the slots 18 and 20 should be large enough for hairs to pass through and the width of the ribs 22 should be large enough to provide sufficient strength without trapping a surplus of hairs. The dimensions of the ribs 22 may also prevent skin from sagging between the ribs 22 and contacting the skin during a shaving stroke.

[0015] As shown in FIG. 2, one or more blades 24a 24b and 24c may be mounted within the housing 12, as shown in FIG. 2. Each of the blades 24a 24b and 24c may have a corresponding cutting edge 26a 26b and 26c. The first blade 24a and first blade edge 26a may be immediately adjacent the ribs 22 of the front face 16. Although three blades 24a, 24b and 24c are shown, the razor cartridge 10 may have more or fewer blades 24 depending on the desired performance and cost of the razor cartridge 10. The open slots 18 and 20 may extend transverse to the cutting edges 26a 26b and 26c. The blades 24a 24b and 24c may be secured to the housing 12 with one or more clips 28a and 28b. The blades 24 may be fixed in the housing 12 or may be resiliently mounted such that the blade members 24, (e.g., respective cutting edges 26) are biased against the clips 28a and 28b. The clips 28a and 28b may aid in retaining the blades 24a, 24b and 24c in an up and down direction (i.e., toward and away from the upper skin contacting surface 14. The clips 28a and 28b may comprise a metal, such as aluminum, but plastic may also be used. The clips 28a and 28b may also be interconnected to form a one-piece assembly. Other assembly methods known to those skilled in the art may also be used to secure and/or mount the blades 24a, 24b and 24c to the housing 12 including, but not limited to, wire wrapping, cold forming, hot staking, insert molding, ultrasonic welding, and adhesives. As will be described in greater detail below, the ribs 22 may prevent the cutting edges 26a, 26b and 26c from contacting the skin during a stroke, so only hair is cut not skin.

[0016] Referring to FIG. 2, an assembly view of the shaving razor cartridge 10 is illustrated. In certain embodiments, the housing 12 may comprise a two-piece assembly. For example, the housing 12 may comprise a base 30 (e.g., a lower portion) and a cage 32 (e.g., an upper portion) that is mounted over the base 30. In certain embodiments, the base 30 may be permanently fixed to the case 32. Accordingly, the cage 32 may define the upper skin contacting surface 14 and the blades 24a, 24b and 24c may be mounted to the base 30. In certain embodiments, the cage 32 may secure the blades 24 within the base 30 (with or without the clips 28a and 28b). For example, the clips 28 may provide either a temporary or an extra measure of securement for the blades 24a, 24b and 24c.

[0017] The base 30 may have a front wall 34 and a rear wall 35 with respective top surfaces 36 and 37. The first blade edge 26a may be immediately behind the front wall 34 to facilitate the unobstructed passage of hair to the first blade edge 26a. One or more of the top surfaces 36 and 37 may be recessed relative to the cutting edges 26a, 26b and 26c. The top surfaces 36 and 37 may extend along a length L1. It is understood that the front wall 34 and the rear wall 35 may have one or more projecting features to aid in securement of the base 30 to the cage 32. The top surfaces 36 and 37 may extend between and positioned below the clips 28a and 28b. The top surface 36 being recessed may allow for an open area in front of the first blade edge 26a so hair is not trapped, as well as provide for an area on the housing for the clips 28a and 28b to rest above the top surface 36. For example, one or more of the top surfaces 36 and 37 may be recessed relative to the first cutting edge 26a by more than 0.20 mm, such that the top surface 36 and 37 do not interfere with or touch the skin, during trimming of hair. As will be explained in greater detail below, all of the blades 24a, 24b, and 24c may be mounted to the base 30 such that the cutting edges 26a, 26b and 26c are positioned above the top surface 36 along the length L1. In certain embodiments, L1 may be about 17 mm to about 35 mm. Accordingly, all the cutting edges 26a, 26b and 26c are not protected by a guard and cap as traditional razor cartridges and thus all the shaving forces would be applied directly to the cutting edges 26a, 26b and 26c because the top surfaces 36 and 37 are recessed such that they do not act as a guard and cap to support (e.g., contact) the skin. However, the cage 32 may be mounted over the base 30 to prevent the cutting edges 26 from contacting the skin, thus resulting in a very safe shave by cutting the hairs to a pre-determined length. The clips 28a and 28b may be mounted to the base 30 prior to the cage 32 being mounted to the base 32. The cage 32 may define a pair of openings 38a and 38b dimensioned to receive the corresponding clips 28a and 28b. The cage 32 may be spaced apart from the clips 28a and 28b, to facilitate simple assembly. For example, the openings 38a and 38b may allow the clips 28a and 28b to be secured to the housing 12 either before or after the cage 32 is mounted to base 30. The openings 38a and 38b may allow the cage 32 to directly contact the cutting edges 26a, 26b and 26c by not resting on top of the clips 28a and 28b. In certain embodiments, the cage 32 would rest directly against the cutting edges 26a, 26b and 26c, thus potentially eliminating the need for the clips 28. Furthermore, hair and shaving debris may become trapped between the cage 32 and the cutting edge 26 if the cage 32 rested on top of the clips 28 and not the cutting edges 26a, 26b and 26c. The openings 38a and 38b may be enclosed and extend between the front face 16 and a rear face 40. As also shown in FIG. 1B, the rear face 40 may interconnect the ribs 22 at a rear of the housing 12 (e.g., cage 32) and lower surface 21 may interconnect the ribs 22 at a front of the housing 12 (cage 32) to reinforce the ribs 22.

[0018] Referring to FIG. 3, a subassembly 44 is shown which may be incorporated in the shaving razor cartridge of FIG. 1. The subassembly 44 may include the base 30, blades 24a, 24b and 24c and clips 28a and 28b. The blades 24a, 24b and 24c may be mounted to the base 30 between the front wall 34 and a rear wall 46. In certain embodiments, the length L1 of the top surface 36 of the front wall 34 may be at least 90% of an overall length L2 of the blades 24a, 24b and 24c that are exposed (e.g., distances between the clips 28a and 28b). The top surface 36 may be bounded on lateral ends 48 and 50 by retaining walls 52 and 54. The retaining walls 52 and 54 may extend above the top surface 36 to facilitate the positioning and securement of the clips 28a and 28b to the base 30. For example, each clip 28a and 28b may be positioned between one of the retaining walls 52 and 54 and a corresponding lateral wall 56 and 58.

[0019] Referring to FIG. 4, a cross section view of the subassembly 44, taken generally along the line 4-4 of FIG. 3 is illustrated. The top surface 36 on the front wall 34 of the base 30 may be positioned a vertical distance of at least 0.5 mm below the cutting edges 26a, 26b and 26c (e.g., a cutting plane 64). In certain embodiments, the vertical distance d1 may be about 0.5 mm to about 5 mm. The position of the top surface 36 may allow the hair to reposition itself in a more upright position as hair is cut (e.g., by the first cutting edge 26a). For example, the top surface 36 may push down and trap long hairs in front of the blades 24, if the top surface 36 was positioned too close to the cutting plane 64 (or the first cutting edge 26a), thus negatively impacting cutting efficiency, especially for longer hairs than tend to lay flat on the skin. One or more of the cutting edges 26a, 26b and 26c may be positioned a vertical distance d2 below a plane P1 tangent to the top surface 36 of the front wall 34 and a top surface 37 of the rear wall 46. The distance d2 may be greatest at the first cutting edge 26a closest to the front wall 34 and the least closest to the rear wall 46. It is believed, without being held to theory, that increasing d2 closer to the front wall 34 improves cutting efficiency. After the hair is trimmed by the first cutting edge 26a, it is less likely to lay flat because it is shorter, thus d2 may be less at the second cutting edge 26b and even less at the cutting edge 26c closest to the rear wall 46. In certain embodiments, d2 may be about 0.5 mm to about 3 mm as measured at any of the cutting edges 26a, 26b and 26c.

[0020] The shaving efficiency of the shaving razor cartridge 10 (FIG. 1) may be enhanced by improving rinsability. Traditional shaving razor cartridges rely on smaller distances between cutting edges or intermediate guards between adjacent blades for improved comfort because pressure is distributed between the cutting edges 26a, 26b and 26c. However, the ribs 22 (FIG. 1) absorb all of the pressure from the skin, not the cutting edges 26a 26b and 26c, which allows the cutting edges 26a 26b and 26c to be spaced further apart from each other. In certain embodiments, distances d3 and d4 between a pair of immediately adjacent cutting edges 26a, 26b and 26c may be greater than 1.75 mm, for example, about 1.8 mm to about 2.0 mm, or about 2.0 mm to about 2.5 mm, which may allow for even more effective rinsing by providing an open gap (as best seen in FIG. 3) between immediate cutting edges 26a, 26b and 26c, without sacrificing trimming efficiency or comfort.

[0021] Referring to FIG. 5, a cross section view of the shaving razor cartridge 10, taken generally along the line 4-4 of FIG. 1 is illustrated. The cage 32 may be mounted to the sub-assembly 44 (i.e., the base 30). The housing 12 (e.g., the base 30 and the cage 32) may allow for hair to freely pass through the slots 20 (FIG. 1) of the front face 16. The upper skin contacting surface 14 and the front face 16 may intersect at an exterior angle A1 that is less than 90 degrees, for example, about 45 degrees to about 85 degrees to facilitate the passage of hair through the slots 20 (FIG. 1) of the front face 16. The intersection of the front face 16 and the upper skin contacting surface 14 may form a radius R1 of the ribs 22. In certain embodiments, R1 may be about 0.1 to about 3 mm and preferably about 0.25 mm to about 1 mm. The lower surface 21 may be positioned a vertical distance d5 of at least 0.5 mm below the cutting edges 26a, 26b and 26c (e.g., about 0.5 mm to about 3 mm). The rear face 40 may have a top surface 60 extending between the ribs 22 (see also FIG. 1B) that is positioned a vertical distance d6 below the cutting edges 26a, 26b and 26c, which may help release the hairs freely (i.e., prevent from hairs being flattened down during a shaving stroke), thus allowing for more efficient trimming of hair.

[0022] The upper skin contacting surface 14 may have an opposing interior surface 62 (e.g., height of the ribs 22). The length of the hair left after trimming with the shaving razor cartridge 10 may be determined by a vertical distance d8 measured from the upper skin contacting surface 14 to the opposing interior surface 62 (e.g., if the cutting edges 26a, 26b, 26c are in contact with the opposing interior surface 62). It is understood that the cutting edges 26a, 26b, 26c may contact or be spaced apart from the opposing interior surface 62. The vertical distance d8 may be about 0.5 mm to about 5 mm and more preferably about 1 mm to about 2.5 mm. If d8 is too small, skin may bulge between the ribs 22 and contact the skin, thus cutting the hair too short. Furthermore, hair longer than 5 mm tends to lay flat and thus will not be cut if d8 is greater than 5 mm.

[0023] It is believed, without being held to theory, that increasing the vertical distance d5 and d6 improves cutting efficacy by minimizing interference of the hair before it is cut by the first cutting edge 26a (for d5) after it is cut by the last cutting edge 26c (for d6). Accordingly, the exposure of the blade edges 26a, 26b and 26c may be determined by d8 (e.g., the height of the ribs 22) and not a feature such as a guard in front of the blades that can push hairs down against the skin making them more difficult to trim. Guards contacting the skin do not present such an issue for typical shaving razors because the cutting edges are contacting and shaving the skin (i.e., cutting hair at or below skin level). Accordingly, the blade edges are able to contact and cut the hairs that may lay flat, lift them up and cut them. However, cutting the hairs above skin level is more difficult because the cutting edges may not be able to reach hairs that lay flat. Accordingly, the housing 12 may define a horizontal gap 66 extending from the first cutting edge 26a to a front interior face 68, opposing the front face 16. In certain embodiments, the horizontal gap 66 may be about 0.5 mm to about 3.0 mm and preferably about 1 mm to about 2 mm. The gap 66 may allow for improved rinsing and allow longer trimmed hairs to rinse out through the housing 12. The gap 66 may also allow for hairs to release and be presented to the first cutting edge 26a in a more upright position. The front wall 34 and top surface 36 may be recessed and thus not extend into the gap 66. It is understood that the lateral end walls 52 and 54 (FIG. 3) are positioned laterally of the bottom surface 36 and thus also does not extend into the gap 66.

[0024] The positioning of the ribs 22 (FIGS. 1A and 1B) over the cutting edges 26a, 26b and 26c helps prevent the skin from contacting the cutting edges 26a, 26b and 26c and eliminates the need of a guard bar in front of the cutting edges 26a, 26b and 26c to support the skin. For example, the height and the spacing of the ribs 22 may prevent skin from bulging between the ribs and contacting the cutting edges 26a, 26b and 26c. Furthermore, the ribs 22 (FIGS. 1A and 1B) may also allow the cutting edges 26a, 26b and 26c to be spaced further apart from each other because the cutting edges 26a, 26b and 26c do not exert pressure against the skin.

[0025] The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. The term about should be interpreted herein as within typical manufacturing tolerances.

[0026] Every document cited herein, including any cross referenced or related patent or application and any patent application or patent to which this application claims priority or benefit thereof, is hereby incorporated herein by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests or discloses any such invention. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.

[0027] While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.