The present invention relates to shaving razor cartridges and more particularly to shaving cartridges that have a housing for retaining and/or rigidly fixing one or more blades.
In general, shaving razors of the wet shave type include a cartridge or blade unit with at least one blade with a cutting edge which is moved across the surface of the skin being shaved by means of a handle to which the cartridge is attached. The cartridge may be mounted detachably on the handle to enable the cartridge to be replaced by a fresh cartridge 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 (i.e., disposable razor). The connection of the cartridge to the handle provides a pivotal mounting of the cartridge with respect to the handle so that the cartridge angle adjusts to follow the contours of the surface being shaved. In such systems, the cartridge can be biased toward a rest position by the action of a spring-biased plunger (a cam follower) carried on the handle against a cam surface on the cartridge housing.
Razor cartridges usually include a guard which contacts the skin in front of the blade(s) and a cap for contacting the skin behind the blade(s) during shaving. The cap and guard aid in establishing the so-called “shaving geometry”, i.e., the parameters which determine the blade orientation and position relative to the skin during shaving, which in turn have a strong influence on the shaving performance and efficacy of the razor. The cap and the guard may aid in establishing the exposure of the blades. Exposure may be defined as the position of the cutting edge of a blade relative to a tangent line drawn from the skin contacting element (e.g., a blade) in front of the cutting edge to the skin contacting element behind the cutting edge (e.g., the cap). A cutting edge positioned above the tangent line would have a positive exposure and a cutting edge positioned below this line would have a negative exposure. A cutting edge that lies on the tangent line has a neutral exposure. Another shaving parameter that significantly effects shave performance is known as span. Span may be defined as the distance from the cutting edge to a skin contacting element immediately in front of the cutting edge (e.g., another blade or the guard). Another parameter that may influence shaving performance is the blade angle. The blade angle is the angle of the cutting edge relative to the tangent line (described above).
In one aspect, the invention features, in general, a wet shaving cartridge having a housing with a guard, a cap, and a pair of spaced apart interior walls between the cap and the guard. A blade retention bump is positioned on at least one of the spaced apart interior walls. At least one resilient blade retention member extends laterally from one of the interior walls toward the other interior wall. At least one clip is mounted to the housing. At least one blade positioned between the resilient blade retention member and at least one of the interior walls wherein the blade is rigidly fixed in a first direction between the clip and the blade retention bumps and retained in a second direction between the resilient blade retention members and at least one of the interior walls.
In another aspect, the invention features, in general, a wet shaving cartridge housing having with a guard, a cap, a pair of spaced apart interior walls between the guard and the cap, and a resilient blade retention member having a fixed end extending from one of the interior walls and a free end extending transverse to the fixed end. The free end and one of the interior walls define a blade slot having a width. The resilient blade retention member deflects from a first position to a second position to receive a blade. The width of the blade slot in the first position is less than the width of the blade slot in the second position.
In yet another aspect, the invention features, in general, a wet shaving cartridge having a housing with a guard, a cap, a pair of spaced apart interior walls between the cap and the guard, and a blade retention bump having a top surface with a radius of about 0.1 mm to about 0.5 mm positioned on at least one of the interior walls. At least one clip is mounted to the housing and least one blade is positioned between the spaced apart interior walls. The blade is rigidly fixed in a first position between the clip and the top surface of the blade retention bump. The wet shaving cartridge may optionally include a resilient blade retention member having a fixed end extending from one of the interior walls and a free end extending transverse to the fixed end. The free end and at least one of the interior walls defines a blade slot having a width. The resilient blade retention members deflect from a first position to a second position. The width of the blade slot in the first position is less than the width of the blade slot in the second position to receive the blade.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features and advantages of the invention will be apparent from the description and drawings, and from the claims.
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The housing 16 and the shaving razor handle 14 may be injection molded from a semi-rigid polymeric material. In certain embodiments, the housing 16 and/or the shaving razor handle 14 may be molded from Noryl™ (a blend of polyphenylene oxide (PPO) and polystyrene developed by General Electric Plastics, now SABIC Innovative Plastics). The housing 16 and/or the shaving razor handle 14 may be molded from other semi-rigid polymers having a Shore A hardness of about 60 to 140, including, but not limited to acrylonitrile butadiene styrene (ABS), acetal, polypropylene, high impact polystyrene, or any combinations thereof. The guard 20 may be molded from the same material as the housing 16 or a softer material. For example, the guard 20 may be molded from materials having a shore A hardness of about 20 to about 70, such as thermoplastic elastomers (TPEs) or rubbers. The cap 22 may also be molded from the same material as the housing 16. In certain embodiments, the cap 22 may have an elongated strip containing a shaving aid to provide lubrication to the surface of the skin during shaving.
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The blades 18 may be mounted within the housing 16 such that the elongated support portion 26 does not bottom out against the housing 16. The length of the blades 18 prior to bending from the cutting edge 30 to the end of the elongated support portion 26 may be highly variable. Since the dimensions related to the tapered portion 28 and the bent portion 32 have a greater effect shave performance these dimensions have tighter tolerances than the length of the elongated support portion 26. Accordingly, elongated support portion 26 may not bottom out within the housing 16 because the tapered portion 28 of the blades 18 are rigidly fixed to the housing 16 between the clips 24 and the blade retention bumps 51. If the elongated support portion 26 bottomed out within the housing 16, the cartridge 12 may not have the desired blade exposure.
In certain embodiments, the blades 18 may be retained within the housing 16 in a first direction between the clips 24 and the blade retention bumps 51. The blades 18 may also be retained within the housing 16 in a second direction, which is different than the first direction. For example, the blades may be retained between the resilient blade retention members 44 and the rear interior walls 45. The first direction may be transverse to the second direction. For example, the first direction may be relative to the top and bottom of the cartridge 12 and the second direction may be relative to the front (e.g., the guard 24) and rear of the cartridge 12 (e.g., cap 22). The blade retention bumps 51 may be fixed relative to the housing 16 (e.g., the cap 22 and the guard 20) to prevent movement of the blades 16 during shaving. The blades 18 may be rigidly fixed in the first direction between the clips 24 and the blade retention bumps 51 such that the blades 18 do not move in an up and down direction during a shaving stroke. However, it is understood that the blade retention bumps 51 and the clips 24 may apply enough pressure against the blades 18 to restrict movement of the blades 18 in any direction under normal shaving conditions. An inner surface 60 of the tapered portion 28 of the blade 18 may directly contact the blade retention bumps 51 (i.e., the top surface 54, as shown in
An inner surface 60 of the tapered portion 28 of the blade 18 may directly contact the blade retention bumps 51 (i.e., the top surface 54). The radius of the blade retention bumps 51 may facilitate the tapered portion 28 to contact the blade retention bumps 51 (i.e., the top surface 54) at a tangent, which may securely fix the blade 18 in place without damaging the blade 18. Bent razor blades may be more susceptible to damage during assembly because of their decreased thickness compared to razor blades that are mounted on blade supports. However, it is understood that the housing 16 may be used for either bent blades or blades that are mounted on thicker blade supports. The tapered portion 28 of the blade 18 may directly contact the clips 24. In certain embodiments, the blade retention bumps 51 may directly contact only the tapered portion 28 and/or the cutting edge 30 of the blade (e.g., not the elongated support portion 26). The blade retention bumps 51 may be spaced apart from the elongated support portion 26 of the blade 16 to improve the flow of water through the cartridge for removing hair and shaving debris. In certain embodiments, the cutting edge 30 of the blade 18 may extend beyond the retention bump 51, but may not extend to the bent portion 32 and/or the elongated support portion 26 of the immediately forward (toward the guard 20) adjacent blade 18. For example, the retention bump 51 that contacts the blade 18 closest to the cap 22 (i.e., the third blade) may be spaced apart from the rear interior wall 45 that contacts the middle blade 18 (i.e., the second blade). Similarly, the retention bump 51 that contacts the middle blade 18 (second blade) may be spaced apart from the rear interior wall 45 that contacts the first blade 18 that is closest to the guard 20. One possible advantage of the spacing of the blade retention bumps 51 and the rear interior walls 45 may be improved rinsing between the blades 18 because the blades 18 are positioned with the cutting edges 30 not overlapping any portion of the preceding blade 18.
It is understood that certain embodiments may include both the blade retention bump 51 and the resilient blade retention member 44. Other embodiments may include either the blade retention bump 51 or the resilient blade retention member 44. In all embodiments, the blade retention bump 51 may be positioned on either the front and/or the rear interior walls 40 and 45. In all embodiments, the resilient blade retention member 44 may extend from either the front and/or the rear interior walls 40 and 45.
The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as “40 mm” is intended to mean “about 40 mm.”
Every document cited herein, including any cross referenced or related patent or application, 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.
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.