Skin engaging device for a safety razor

Technical field The invention relates generally to a wet shaving implement, in particular to razor cartridges having an improved skin-sticking device. The invention essentially consists in the development of a device with a surface shape adhering to the skin in the sheath and / or lid that brings the shaving aid material to the skin as the razor moves over the skin.

Background Art [0002] In wet shaving systems, factors that include, but are not limited to, the friction resistance of blades sliding over the skin, the force needed to cut hair, and irritation of existing skin damage, can cause some degree of discomfort. The discomfort and other problems associated with wet shaving systems can be alleviated by applying shaving aid materials to the skin. Shaving aid materials can be used before, during and after shaving. Many problems are associated with the use of shaving aid before and after shaving. Shaving aid materials used before shaving may evaporate, be removed from the area of ​​use with repeated knife strokes, or may be washed with water from the area where they are placed on the skin. Shaving aid materials used after shaving are absent from the skin during shaving, and therefore their use may be late to counteract the occurrence of an unwanted shaving effect. The use of both pre-shave and after shave enhancement materials is an additional operation to the shaving process.

[0003] Many solutions have been proposed to date, and their purpose was to incorporate a shaving aid material, e.g., a lubricant, a hair softener, a knife cleaner, a medicament, a cosmetic, or a combination thereof, into a razor, e.g. by placing shaving aid material in the razor cavity, by incorporating the shaving aid material directly into one or several components of the molded razor polymer, by gluing the shaving aid composite to the razor, and by forming a mechanical joint between the shaving aid composite and the razor. The water-soluble shaving aid material, e.g., polyethylene oxide, was mixed with the water-insoluble matrix material, e.g., a polystyrene polymer, to form the insoluble polymer / soluble shaving aid composite disclosed in US-A-4,170,821 and in US-A-5,113,858. The composite was attached to the razor and to the razor cartridge structure near the cutting edge or cutting edges of the shaving systems with one or more razor blades. After contact with water, the water-soluble shaving aid material gets from the composite to the skin. These composites tend to dispense a large amount of shaving aid material during the first few shaving operations and dramatically reduce the amount of shaving aid material during subsequent shaving operations. In addition, injection molded composites with a relatively large amount of shaving aid material (up to 80% by weight) and a relatively small amount of water insoluble matrix material (only 20% by weight) are relatively weak and have a tendency to mechanical damage during manufacture, during assembly, and during use. composite. The increase in strength must be associated with the increase in insoluble matrix material. However, such an increase reduces the ratio of the amount of shaving aid material in the composite and the ability to dispense the shaving aid material.

[0004] Commercial lubrication strips, especially those containing a large amount of polyethylene oxide, for example those described in the publications mentioned above, tend to deteriorate after use. The extraction rate changes during the shaving operation and usually only about 50% of the polyethylene oxide can be in the strip later. The selection of a polyethylene oxide support (e.g., a water insoluble matrix material) is limited to a support that has a low melting or softening point and is at least partially miscible with polyethylene oxide. In addition, because the strip is manufactured at a high temperature of approximately 180^aboutC, it's difficult to put additives like fragrances and plasticizers in it.

[0005] US-B-6,298,558 discloses an improved device intended for use in razor inserts and wet shaving systems. In one embodiment, a two-component shaving apparatus is provided, with controlled dispensing of shaving aid material, consisting of a thermoplastic resins layer with openings therein, and a core containing shaving aid material in its interior. Potentially, the device can maintain the appropriate surface appearance, can release shaving aid materials in a controlled manner, can minimize degradation of shaving aid materials, can minimize the amount of shaving aid materials contained in a belt, and can be a device that is easy to manufacture and / or easily integrated with the razor cartridge system. Document

US-B-6,298,558 discloses a production method, including device manufacture, consisting of its two-component injection molding or co-injection molding, cutting to a length suitable for embedding in or on the body of the razor cartridge. Length trimming reveals the core at both ends of the device. In use, upon contact with water, the device may exhibit accelerated recovery of the shaving aid material from the exposed ends of the core and recovery in a direction that the shaving aid material will not deposit on the skin and will therefore be lost. Because many shaving aid materials tend to swell when they come in contact with water, the exposed ends of the device may expand uncontrollably, which can cause premature wear of the entire device.

[0006] Further, US-A-5,915,791 discloses a shaving unit having skin-tightly extending projections located in front of the blades and a water-soluble composite shaving aid material disposed behind the skin-fitting projections. The composite shaving aid material is positioned in a recess in a shield strip located at the front edge of the shaving unit frame, between the side walls of the frame substantially perpendicular to the shield strip. The configuration and materials of the water-soluble shaving aid material may be as described in said US-B-6,298,558.

Based on the foregoing, it is desirable to develop a co-extruded device for providing shaving aid material or shaving aid materials for a razor cartridge or shaving system provided with a water insoluble polymer sheath and a core containing a water soluble shaving aid material. The device is cut to length and its ends are closed, preventing the ingress of water and preventing premature extraction of shaving aid material, or premature wear of the device.

Description of the invention [0008] The razor cartridge or shaving system of the present invention as defined in claim 1 includes a device for dispensing shaving aid material onto a user's skin surface during a normal shaving operation. The device has a longitudinal, solid body made of water insoluble polymer, and an internal, solid body injection molded polymer core with the shell. The core contains 50% to 100% by weight of a solid having shaving aid material having a form of polyethylene oxide. The shield has a surface adhering to the skin along its outer surface and at least one hole in the surface adhering to the skin through which the shaving aid material is dispensed. The ends of the device are at least partially bonded to prevent water ingress and / or to dispense shaving aid material from the end of the device.

[0009] In an embodiment of the present invention, the sheath at one end of the device extends axially beyond the core. One protruding part of the sheath is bonded, for example with a suitable adhesive, or is welded, for example by ultrasonic welding, to the other protruding part of the sheath to close this end of the device.

In another embodiment of the present invention, an adhesive is applied to one end of the device. The adhesive is selected for its properties including the inability to penetrate the core too much. The adhesive may conveniently be included in the volatile carrier for easier application.

[0011] In yet another embodiment of the present invention, the end of the device is closed by an end cap. The end cap may be formed of molded polymeric material or drawn metal material. The end cap can be bonded or welded to the device as described above, or mechanically mounted on it.

[0012] Embodiments of the invention may have one or more of the following advantages. The end parts of the device are closed, preventing water from penetrating during use and preventing premature extraction of shaving aid material, or premature wear of the device. The above features and advantages of the present invention will become fully understood upon reading the detailed description below referring to the accompanying drawings.

Brief description of the drawings [0013]

Fig. 1 is a perspective view of the razor cartridge of the present invention.

Fig. 2 is a section 2-2 of Fig. 1.

Fig. 3 is a cross-sectional view of the razor cartridge of the present invention, in another embodiment thereof.

Fig. 4 is an enlarged perspective view of the device of the present invention.

Fig. 5 is an enlarged perspective view of the device of the present invention in another embodiment thereof.

Fig. 6 is an enlarged perspective view of the device of the present invention in yet another embodiment thereof.

Detailed description [0014] Referring to the drawings, the shaving unit 10 shown in Figs. 1 and 2 has a base or support 12, formed of ABS or other suitable polymeric material, including an integrated set of coupling grooves 14, used to attach the shaving unit. to the razor handle, and a cover 16 that has a transverse front skin-adjacent surface 18. On the upper surface of the support 12 is placed a front shaving knife 20 having a cutting edge 22, a rear shaving knife 24 having a cutting edge 26, and an aluminum spacer 28 that maintains an adequate gap between the blades 20 and 24. The cover 30 is also formed of ABS or other suitable polymeric material and is provided with a base 32 that has a rear skin-adherent surface 34, transversely positioned between the forward-reaching end walls 36, and has a front edge 38 which is positioned with behind the cutting edge 26 of the knife. The lid is integrated with rivets 40 protruding down from the transversely located base 32 and passing through the holes in the blades 20 and 24, in the spacer 28 and the support 12, securing the cover 30, the blades 20 and 24, and the spacer 28 to the support 12. W the skin 42 adhered to the skin 34. The shaving unit 50 shown in Fig. 3 is of the type disclosed in US-A4,586,255 and is equipped with a support 52 having a front portion 54 and a rear portion 56. The sheath 58 may be flexibly or rigidly attached to the support and may also include a plurality of elastomer ribs as is well known to those skilled in the art. The shaving unit is equipped with a front shaving blade 60 mounted on a folded support 61 and a rear shaving blade 62 mounted on a folded support 63. One skilled in the art should understand that a shaving unit may be equipped with one, two, or three, or a larger number of blades, and the present invention is not limited in this regard. The shaving aid composite, having the form of an elongated device 64, is blocked by thorns in the opening 66 of the rear portion 56.

[0016] Figures 4-6 generally show variants of the present invention. The expression "core" used in this text means the internal part of the device adjacent to the skin visible on the cross-section. The core is located in the device adjacent to the skin along its axis. This axis does not have to be the middle axis. In Fig. 3 the core is marked 70 and the sheath 72. In various embodiments of the present invention there is at least one core. The term "sheath" as used in this text means the outer layer or layers covering the core 70. The core and sheath device 64 is preferably manufactured in a two-component injection molding process and is cut to a length suitable for embedding in or on the body of the razor cartridge. The core contains 50-100% water-soluble shaving aid material in the form of polyethylene oxide. Preferred sheath materials are disclosed in US-B-6,298,558. The skin-adhering surface 74 of the shield is provided with at least one opening 78 through which the shaving aid material is released towards the skin. The device is preferably provided with about 3 to about 30 holes 78, most preferably with 10-15 holes evenly spaced along the skin surface 74. The skin-adhering surface 74 of the cover may also be provided with a soft layer, for example a commercially available strap (polyethylene oxide / polystyrene), which becomes porous during use. Referring to Fig. 3, the device is provided with an elongated insert 76. The insert 76 can be frictionally locked in the opening 66, as seen in Fig. 3.

[0017] Fig. 4 shows an example of the present invention. The end cap 80 is placed at the end of the device 64 closing this end, preventing water from entering this end of the device and preventing dispensing shaving aid material from the exposed core. The end cap may be made of molded polymeric material, most preferably a polymeric material selected to be easy to weld with a shield. The end cover may also be attached to the device by means of a suitable glue, e.g. cyanoacrylate glue, most preferably of the type designated LOCTITE 420, manufactured by HENKEL. The end cover can also be made of drawn metals, especially aluminum alloy glued to the device as described above. The drawn metal of the end cap can also be attached to the device by drilling the end wall of the lid so that part of the end cap penetrates the device and prevents its removal.

[0018] Fig. 5 shows another solution according to the present invention. The end of the device visible after cutting it to length is closed by applying a suitable foil or sealant 90. The sealant is preferably a varnish having a volatile component that evaporates after applying the sealant. The sealant is selected at least in terms of its ease of attachment to the sheath to form a strong layer, and its inability to penetrate the core and thus affect the dispensing of the shaving aid material through the holes 78 during normal shaving. The sealant may also be room temperature vulcanized (RTV) material containing silicone or a two-component epoxy adhesive.

[0019] Fig. 6 shows another embodiment of the present invention. The segment 100 at the end of the device is crushed or otherwise compressed, removing part of the core in place of the crushed section of the device. The inner opposing walls of the sheath are preferably ultrasonically or otherwise welded together to form a seam 102 closing the end of the device. The inner opposing walls of the enclosure can be glued together as described above.

[0020] It should be understood that the present invention is by no means limited to the particular structure described herein and / or shown in the drawings, but also includes any modifications within the scope of the appended claims.

Eveready Battery Company, Inc., United States Representative:

EP 2 046 540 B1

Z-9250/12