The present invention relates to safety razors including a handle and a blade unit having at least one blade. More particularly, the present invention relates to a safety razor having the blade unit being connected to the handle for a pivotal movement relative thereto about a pivot axis substantially perpendicular to the blade for following the skin contours of a user during shaving.
Conventional safety razors have a blade unit connected to a handle for a pivotal movement about a single pivotal axis which is substantially parallel to the blade (i.e., the blade edge). The pivotal movement about the single axis provides some degree of conformance with the skin allowing the blade unit to easily follow the skin contours of a user during shaving. The pivot axis, which usually extends parallel to the cutting edges of the blades, can be defined by a pivot structure where the handle is connected to the blade unit. Such safety razors have been successfully marketed for many years. However, the blade unit often disengages from the skin during shaving as it has limited ability to pivot about the single axis.
To address this problem, it was suggested that the blade unit can additionally pivot about another axis which is substantially perpendicular to the blade(s). For example, U.S. Pat. No. 5,029,391 discloses such a razor having a blade unit capable of a pivotal movement about a pivot axis substantially perpendicular to the blade(s). It is disclosed that the blade unit can carry out a pivoting movement about two axes, so that the safety razor blade unit can optimally conform to the contour of the face during shaving. Other examples of safety razors which have a blade unit capable of pivotal movements about two pivot axes are disclosed in U.S. Pat. Nos. 6,615,498; and 5,953,824; and Japanese Patent Laid Open Publication Nos. H2-34193; H2-52694; and H4-22388.
While it is disclosed that these razors help the blade unit to more suitably follow the skin contours of a user, they tend to have a complicated structure to implement the pivotal movements about two pivot axes and thus cause a difficulty in manufacturing.
Thus, there is a need for a safety razor having a blade unit capable of a pivotal movement about a pivot axis substantially perpendicular to the blade, which can be produced by a simplified manufacturing process. There is also a need for a safety razor having a blade unit capable of pivotal movements about two pivot axes, which can be produced by a simplified manufacturing process.
The invention is directed to a safety razor which includes a handle and a blade unit having at least one blade. The blade unit is connected to the handle for a pivotal movement relative thereto about a perpendicular pivot axis which is substantially perpendicular to the at least one blade for following the skin contours of a user during shaving. The blade unit has a rest position towards which the blade unit is biased by a return force when pivoted about the perpendicular pivot axis away from the rest position.
In one aspect, one of the handle and the blade unit has a concave portion formed on its surface. The safety razor further includes: (a) a relative movement transfer member formed between the handle and the blade unit for transferring a relative movement between the handle and the blade unit caused by the pivotal movement, and (b) a return force generating member formed in the concave portion for generating a return force for the blade unit in response to the relative movement transfer member. The return force generating member includes (i) a holding structure for holding a part of the relative movement transfer member, and (ii) an elastic member connected to the holding structure for generating the return force in response to the relative movement transfer member.
In this aspect, since the return force generating member is held in the concave portion which is formed on the surface of the handle or the blade unit, the safety razor can be produced by a simplified manufacturing process.
In another aspect, the safety razor further includes: (a) a relative movement transfer member formed on the perpendicular pivot axis for transferring a relative movement between the handle and the blade unit caused by the pivotal movement, and (b) a return force generating member formed on the perpendicular pivot axis for generating a return force for the blade unit in response to the relative movement transfer member. The relative movement is given by a rotation angle difference about the perpendicular pivot axis, while the return force is given by a torque about the perpendicular pivot axis.
In this aspect, since the relative movement transfer member and the return force generating member are formed on a common axis, the structure of the safety razor can be simplified.
While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter which is regarded as forming the present invention, it is believed that the invention will be better understood from the following description taken in conjunction with the accompanying drawings.
Herein, “comprise” and “include” mean that other elements and/or other steps which do not affect the end result can be added. Each of these terms encompasses the terms “consisting of” and “consisting essentially of”.
Herein, “connected” encompasses configurations in which an element is directly secured or mounted to another element by affixing the element directly to the other element; configurations in which the element is indirectly secured or mounted to the other element by affixing the element to an intermediate member which is affixed to the other element; and configurations in which one element is integral with another element, i.e., one element is essentially part of the other element.
The blade unit 11 is connected to the handle 12 for movement relative thereto about a first pivot axis (or, “parallel pivot axis”) 61 which is substantially parallel to the edges of the blades 20. More specifically, the blade unit 11 is connected to the connecting member 18 and is pivotally moveable about the first pivot axis 61. The first pivot axis 61 is preferably in front of the blades and below a plane tangential to the guard 14 and cap 15 surfaces, although other pivot positions are possible. In other words, the blade unit 11 pivots about the first pivot axis 61 in response to the force applied from the skin and the return force during shaving.
The return force generated by the springs can be either linear or non-linear acting to return the blade unit 11 to the rest position. The torque range of the return force is from about 0 to about 15 Nmm as the blade unit 11 pivots from its rest position about the first pivot axis 61 through the complete pivot range. Other torque ranges both larger and smaller may be used as desired. The torque can be varied by varying the physical property of the springs used. Preferably, the blade unit 11 has a pivot range up to about 45° about the first pivot axis 61. Other pivot ranges both larger and smaller may be used as desired.
The blade unit 11 is also connected to the handle 12 for a pivotal movement relative thereto about a second pivot axis (or, “perpendicular pivot axis”) 62 which is substantially perpendicular to the blades 20 for following the skin contours of a user during shaving. The handle 12 is pivotally connected to the connecting member 18 about the second pivot axis 62. The connecting member 18 (which is a part of the blade unit 11) has a rest position towards which the connecting member 18 is biased by a return force when pivoted about the second pivot axis 62 away from the rest position.
The second pivot axis 62 is substantially perpendicular to the handle axis (not shown in Figs. but it coincides with the central axis of the handle 12). If desired, the second pivot axis 62 can be set between 5 degrees and 30 degrees from a virtual plane (not shown in Figs.) which is perpendicular to the handle axis. In one embodiment, the second pivot axis 62 is set at 18 degrees from the virtual plane.
In the embodiment shown in
The safety razor 10 further includes: (a) a relative movement transfer member 30 formed between the handle 12 and the blade unit 11; and (b) a return force generating member 40 formed in the concave portion 22. The relative movement transfer member 30 transfers a relative movement between the handle 12 and the blade unit 11 which is caused by the pivotal movement about the second pivot axis 62, to the return force generating member 40. The return force generating member 40 generates a return force for the blade unit 11 in response to the relative movement transfer member 30. The relative movement transfer member 30 typically includes a rod-like shaped member (e.g., a shaft) which couples the handle 12 to the blade unit 11.
The blade unit 11 has a third (or movable) axis 63 which is movable in response to the relative movement between the handle 12 and the blade unit 11 while it (i.e., the third axis 63) is being kept parallel to the second axis 62. In the embodiment shown in
Referring to
The return force generating member 40 is formed in the concave portion 22 formed on the surface of the blade unit 11 or the handle 12. The concave portion 22 can take any shape formed on the surface of the blade unit 11 (including the blade unit 11) or the handle 12. Herein, “concave portion” refers to a portion of the handle or the blade unit formed on its surface, which has a shape and a depth to hold (or house) at least a part of (and preferably the most or entire part of) the return force generating member. Herein, “surface of a handle or a blade unit” is a part of the handle or the blade unit which is exposed to (i.e., can be seen from) the outside before the blade unit is connected to the handle in the manufacturing process. Since the return force generating member is held in the concave portion which formed on the surface of the handle or the blade unit, the safety razor can be produced by a simplified manufacturing process, compared to implementing such a function by mechanical elements (e.g., springs).
In one embodiment, the concave portion provides enough space to house the return force generating member. For example, the concave portion 22 has a slightly larger dimension than that of the return force generating member 40 to house the entire return force generating member 40. The concave portion is typically formed below the adjacent surface(s) of the handle and the blade unit but alternatively, it can be formed above the adjacent surface(s) of the handle and the blade.
In another embodiment, the concave portion of one of the handle and the blade unit faces (or is exposed to) a part of the other of the handle and the blade unit. In the embodiment shown in
The holding structure 41 of the return force generating member 40 can take any shape or structure which can receive the relative movement transmitted from the relative movement transfer member 30. In the embodiment shown in
In the embodiment shown in
The return force generating member 40 (i.e., at least the elastic member 42 or the elastomeric elements 46) is formed by an elastomeric material. Such an elastomeric material can include synthetic or natural rubber materials. One example of such an elastomeric material for use herein is a polyether-based thermoplastic elastomer (TPE) which is available from Kraiburg HTP under Code No. 1028/55. Another example of such an elastomeric material for use herein is a polyether-based thermoplastic vulcanizate elastomer (TPVs) which is available from Exxon Mobil Corporation under Code No. Santoprene™ 101-55/201-55.
In one embodiment, the outer support 43, the elastic member 42 (or the elastomeric elements 46) and the outer support 43 are formed by an identical material. The physical property of the elastic member 42 can vary depending on the dimensions of the elastic member 42 or the elastomeric material selected. Alternatively, the outer support 43, the elastic member 42 (or the elastomeric elements 46) and the outer support 43 can be formed by different materials.
In the embodiment shown in
The return force generating member 40 can take a layered structure formed by two (or more) different elastomeric materials. Herein, “different elastomeric materials” refers to two (or more) materials which have different elastic characteristics (e.g., elasticity). The different elastomeric materials do not have to be formed by two (or more) materials but can be formed by an identical elastomeric material by selecting different physical parameters on each layer (i.e., thickness, density, etc.).
In the embodiment shown in
In
In
Similarly, the blade unit 11 and the return force generating member 40 work when the opposite force (to the force F1) is applied to the blade unit 11 from the skin during shaving.
The return force generated by the return force generating member 40 can be either linear or non-linear acting to return the blade unit 11 to the rest position RP. The torque range can be from about 0 to about 15 Nmm as the blade unit 11 pivots from its rest position RP about the second pivot axis 62 in either direction through the complete pivot range. Other torque ranges both larger and smaller may be used as desired. The torque can be varied depending on the elastic property of the return force generating member 40 used. In the embodiment shown in
The blade unit 11 can have a pivot range (about the second pivot axis 62) up to about 15° in either direction from the rest position. Other pivot ranges both larger and smaller may be used as desired. In the embodiment shown in
Since the blade unit 11 can carry out a pivoting movement about the two axes 61 and 62, the safety razor blade unit 12 can optimally conform to the contour of the face during shaving.
Referring to
The safety razor 310 further includes: (a) a relative movement transfer member 330 formed between the handle 312 and the blade unit 311; and (b) a return force generating member 340 formed in the concave portion 322. The relative movement transfer member 330 transfers a relative movement between the handle 312 and the blade unit 311 (through the connecting member 318) which is caused by the pivotal movement about the second pivot axis 62, to the return force generating member 340. The return force generating member 340 generates a return force for the blade unit 311 in response to the relative movement transfer member 330. The relative movement transfer member includes a rod-like shaped member (not shown in
The blade unit 311 has a third (or movable) axis 65 which direction is movable in response to the relative movement between the handle 312 and the blade unit 311 while it (i.e., the movable axis 65) is being kept perpendicular to the second pivot axis 62. In the embodiment shown in
In the embodiment shown in
The second end (not shown) of the shaft 333 is fixed in the blade unit 311. The shaft 333 transfers a relative movement between the handle 312 and the blade unit 311 which is caused by the pivotal movement about the second pivot axis 62, to the return force generating member 340. The relative movement transfer member 330 (or the shaft 333) and the holes 347 are disposed along the third axis 65.
The holding structure 341 can take any shape or structure which can receive the relative movement transmitted from the relative movement transfer member 330. In the embodiment shown in
Similarly to the subassembly shown in
In the embodiment shown in
The return force generating member 640 includes (i) a holding structure 641 having a round hole 647, (ii) an elastic member 642 connected to the holding structure 641, (iii) an outer support 643; and (iv) an attachment arm 644. The attachment arm 644 extends from the outer support 643 and fixes the return force generating member 640 to the handle 412 as shown in
Compared with the safety razor 410 shown in
The safety razor 510 further includes a relative movement transfer member 530 formed between the blade unit 511 and the handle 512 for transferring a relative movement between the blade unit 511 and the handle 512 caused by the pivotal movement.
The return force generating member 540 includes (i) a holding structure 541 having a round hole 547 for holding a part of the relative movement transfer member 530, and (ii) an elastic member 542 connected to the holding structure 541 for generating the return force in response to the relative movement transfer member 530. The relative movement transfer member 530 includes a projection 571 formed on the axis 66 (i.e., the projection 571 has a central axis (not shown) which coincides with the axis 66). The projection 571 transfers the relative movement between the blade unit 511 and the handle 512 by rotational angle about the central axis 66.
For an effective operation, the outer surface of the return force generating member 540 is fixed to the inner surface of the hole 524, while the outer surface of the relative movement transfer member 530 is fixed to the inner surface of the hole 547 of the holding structure 541. These fixing structures can be implemented by applying an adhesive between the surfaces. Alternatively, these fixing structures can be implemented without such an application of adhesive if the related elements are so precisely designed and manufactured that the surfaces can generate enough friction which prevents slide between the surfaces.
In operation, when the blade unit 511 pivots about the pivot axis 62 for following the skin contours of a user during shaving, the projection 571 (i.e., the relative movement transfer member 530) rotates about the pivot axis 62 in response to the force applied through the relative movement transfer member 530. In other words, the relative movement transfer member 530 is formed on the second axis 62 for transferring the relative movement which is given by a rotation angle difference about the second axis 62.
The rotation angle produces a strain at the elastic member 542 of the return force generating member 540. The return force generating member 540 generates a return force which tries to move the blade unit 511 to the rest position. In other words, the return force generating member 540 is formed on the second axis 62 for generating the return force which is given by a torque about the second axis 62.
The elastic member 842 includes an elastomeric element (or bar) 846 formed by an integral plastic molding which is used for producing the handle 12 in the manufacturing process. In other words, the elastomeric element 846 is formed by the same manufacturing process (and at the same time) as that for producing the handle 12. This is beneficial since this embodiment does not require a return force generating member which is produced by a separate manufacturing process from that used for producing the handle 12. In addition, since the elastic member 842 is integral with the handle 12, the assembling process for connecting the blade unit 11 to the handle 12 can be simplified.
Modifications to the described embodiments are of course possible without departing from the principles of the invention. It is to be understood, therefore, that the specifically described embodiments are given by way of non limiting example only and it is intended that the invention should be limited only by the claims which follow.
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.
This application claims the benefit of U.S. Provisional Application No. 61/132,494, filed on Jun. 19, 2008.
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