Patent Application
20090049695
This invention relates to safety razors and, more particularly, to safety razor cartridges having a guard.
In recent years wet-shaving, so-called “safety razors” having a cartridge with various numbers of blades and a guard have been proposed in the patent literature and commercialized, as described e.g., in U.S. Pat. No. 5,787,586, which generally describes a type of design that has been commercialized as the three-bladed Mach III razor, and in U.S. Pat. No. 7,197,825, which generally describes a type of design that has been commercialized as the five-bladed Fusion razor, both by The Gillette Company. The guard is located forward of the blades and is used to stretch the skin and prepare hairs for shaving.
Some razors have guards with larger contact areas to increase skin stretching and hair preparation by providing greater numbers of skin stretching elements, such as surfaces, fins, ribs, fingers, or the like. But shave prep and/or shave debris may accumulate between the guard and the skin during one or more shaving strokes. Under one hypothesis, the accumulation restricts the guard from frictionally engaging the skin (i.e., drag) and may tend to lessen skin stretch to during each stroke. Skin stretching tends lead to better closeness buy forcing hairs to protrude farther from their follicles. Under another hypothesis. the accumulation may cause so-called “hydroplaning” of the cartridge, which is a lifting the cartridge blades away from the skin by the shave prep in between the guard and the skin, thereby potentially reducing the closeness of the shave. Guards with larger contact areas may experience more hydroplaning.
This invention relates to safety razors and, more particularly, to safety razor cartridges having a guard.
In one aspect, the invention features, in general, a shaving blade unit having a plastic housing with a front portion and a rear portion and two side surfaces extending from the front portion to the rear portion. A shaving blade is disposed between the front portion and the rear portion and has a blade length extending along a blade axis. A guard is disposed at the front portion of the housing and includes an elastomeric member forming at least one passage extending between an upper surface and a lower surface of the elastomeric member.
In another aspect, the invention features, in general, a shaving razor having a handle and a shaving cartridge including connection structure connecting the cartridge to the handle. The shaving cartridge has a plastic housing with a front portion and a rear portion and two side surfaces extending from the front portion to the rear portion. A shaving blade is disposed between the front portion and the rear portion and has a blade length extending along a blade axis. A guard is disposed at the front portion of the housing. The guard has an elastomeric member forming at least one passage extending between an upper surface and a lower surface of the elastomeric member.
Certain implementations of the invention may include one or more of the following features. The passage is configured for fluidic communication between the upper surface and the lower surface. The elastomeric member has a leading portion extending beyond a leading edge of the plastic housing front portion and a following portion supported by the plastic housing front portion. The leading portion forms the at least one passage. The elastomeric member forms a channel in the upper surface extending from and in communication with the passage toward a front surface of the elastomeric member. The elastomeric member forms the channel in the front surface, the channel extending from the upper surface toward the lower surface. The elastomeric member has a wall member disposed on the upper surface and configured to direct shave prep into the passage. The elastomeric member forms multiple passages. The elastomeric member forms multiple channels in the upper surface, each channel extending from a respective passage toward a front surface of the elastomeric member. The elastomeric member comprises an elastomeric fin. The fin extends along a fin axis that is generally parallel to the blade axis, the fin having a length along the fin axis that is greater than or equal to the blade length. The elastomeric fin is made of a material having a Shore A hardness between about 30 and 60. The elastomeric member includes multiple elastomeric fins. The fins are arranged in parallel rows. the fins extending along respective fin axes that are parallel to the respective one or more blade axes, at least some of the fins having a length along an associated fin axis that is longer than the blade length. The shaving cartridge is permanently connected to the handle. The shaving cartridge is removably connected to the handle. The housing defines a connection structure adapted to connect the blade unit to the handle. The connecting structure is a bearing surface defining a pivot axis about which the plastic housing is pivotally supportable.
Referring to
Cap 24 provides a lubricious shaving aid and is received in a slot at the rear of housing 20. Cap 24 may be made of material comprising a mixture of hydrophobic material and a water leachable hydrophyllic polymer material, as is known in the art and described e.g., in U.S. Pat. Nos. 5,113,585 and 5,454,164 which are hereby incorporated by reference. Details of the cartridge as so far described can be found in U.S. Pat. No. 7,197,825, the entire contents of which are herein incorporated by reference.
Referring to
The elastomeric member 100 is supported along a rear portion 102 and side portions 104 by housing 20. Referring now to
Referring again to
Referring also to
Referring to
In some examples, elastomeric member 100 forms channels 138 in the upper surface 132 extending from one or more, preferably one for each of, ducts 130 to front wall 140 of member 100 for further directing shave prep into ducts 130. As elastomeric member 100 is moved along the skin during a shaving stroke, shave prep enters channels 138 and is wiped from the skin by wiping member 136. As wiped shave prep accumulates in channels 138, fresh shave prep entering channels 138 drives wiped shave prep rearwardly and through ducts 130, thereby reducing the shave prep between the skin and fins 114 and reducing the likelihood of hydroplaning.
Referring to
In the embodiment shown, group 112 includes 9 fins. Generally, the elastomeric member may include fewer or more fins (e.g., between about 5 and 15 fins). For a given pitch and fin geometry, more fins will generally give greater skin stretch, for a closer shave; however, above a certain number of fins the skin stretch tends not to increase (or increased skin stretch is not necessary) and the elastomeric member may become overly wide, making it difficult for the user to shave in tight areas.
Referring back to
The material for forming the elastomeric member 100 can be selected as desired. Preferably, the elastomeric member is formed of an elastomeric material, such as block copolymers (or other suitable materials), e.g., having a durometer between 28 and 60 Shore A. Preferably, fins 114 are also made of a relatively soft material, e.g., having a Shore A hardness of between about 28 and 60 (for example, between about 40 and 50, such as between about 40 and 45 Shore A). As values are increased above this range, performance may tend to deteriorate, and as values are decreased below this range there may be production problems. As shown, the fins and elastomeric member are integrally formed of the same material. In other cases, the fins and elastomeric member are formed of differing materials.
The manufacturing method for forming elastomeric member 100 can be selected as desired. Preferably, elastomeric member 100 is formed onto housing 20 by a two material injection molding process. Referring to
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.”
All documents cited in the Detailed Description of the Invention are, in relevant part, incorporated herein by reference; the citation of any document is not to be construed as an admission that it is prior art with respect to the present invention. 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.
