Cutlery – Razors – Including particular handle or razor handle – per se
Reexamination Certificate
2000-01-20
2001-11-06
Payer, Hwei-Siu (Department: 3724)
Cutlery
Razors
Including particular handle or razor handle, per se
C030S050000, C030S057000
Reexamination Certificate
active
06311400
ABSTRACT:
This invention is concerned with safety razors and more especially, the invention relates to a safety razor in which a blade unit is mounted on a handle by a supporting structure permitting movement of the blade unit relative to the handle for following the contours of the skin as the blade unit is moved across the skin during shaving. In particular, the invention disclosed herein resides in a support structure providing for the blade unit a suspension allowing movement of the blade unit towards the razor handle.
There have been various proposals for mounting a blade unit on a handle to enable movement of the blade unit with the intention of maintaining conformity of the skin contacting parts with the skin surface during shaving. For example, many razors currently marketed have blade units which are pivotable about longitudinal axes parallel to the blade edges. In our prior patent application No. GB-A-2116470 there is described a razor in which the blade unit supporting structure also allows pivotable movement about a transverse axis. A safety razor disclosed in WO 89=l /01394 has a blade unit support structure constructed so that the blade unit is pivoted on journals formed at the ends of two parallel arms, pivotal movement of the blade unit from a rest position is opposed by a cam arrangement, and the two arms are retractable against springs acting thereon under forces generated by pressing the blade unit against the skin so that the cam arrangement disengages to allow substantially free pivotal movement of the blade unit. With the known constructions, however, the ability of the blade unit to respond to chances in the skin surface contours in order to follow those contours with a view to improving shaving performance is limited by constraints imposed on the blade unit movements by the support structure.
There is proposed in our copending International patent application No. PCT/GB97/00121, an arrangement for mounting a blade unit to a handle which provides for improved freedom of movement of the blade unit relative to the handle by use of several spring suspension devices. More particularly, the blade unit is capable of movement with several degrees of freedom including pivotal movement about a longitudinal axis, pivotal movement about a transverse axis and translational movement in a direction generally towards the handle and substantially perpendicular to a plane defined by the longitudinal and transverse axes. The position of the transverse axis is not fixed and the embodiments described in the aforesaid application allow end-to-end tilting of the blade unit.
The present invention has for its object to provide a blade unit supporting structure capable of achieving the freedom of movement proposed according to the invention of the aforementioned international patent application whilst being convenient to manufacture and allowing a uniform pivoting characteristic with respect to the longitudinal axis which need not be influenced by other blade unit displacements.
Embodiments of the present invention as described herein comprise a structure for supporting an elongate blade unit with respect to a handle structure, there being a blade unit engaging structure that engages the blade unit and provides pivotal mounting of the blade unit about a pivot axis that is parallel to a longitudinal axis of the blade unit, and a resiliently deformable arm structure connected between the handle structure and said blade unit engaging structure. The arm structure permits displacement of the engaging structure downwardly towards the handle structure whilst restraining movement of the engaging structure in a direction substantially perpendicular to the direction of downward displacement.
Stated more specifically the present invention provides a blade unit supporting structure for suspension mounting of an elongate blade unit to a handle in a safety razor, the structure comprising a blade unit engaging section including at least one pivot element defining a pivot axis substantially parallel to the length of the blade unit for pivotal movement of the blade unit about said axis, and a suspension section or yoke including a hub for firm attachment to the handle and a pair of arms extending symmetrically from the hub and connected to respective portions of the blade unit engaging section disposed to be adjacent opposite ends of the blade unit, the arms being resiliently displaceable to permit independent movement of each end of the blade unit towards the handle from a rest position to which the blade unit is biased by the arms, and the arms restraining movement of the engaging section, and thereby the blade unit, in a direction substantially perpendicular to a plane defined by said direction of movement towards the handle and said pivot axis.
In a preferred construction a pivot element is provided on each blade unit engaging portion so that the blade unit is pivotally mounted at its ends. The blade unit engaging portions are interconnected by a substantially rigid strut member, which serves to eliminate relative movement of the blade unit engaging portions which is undesirable. The engaging section includes an element for cooperating with the blade unit to resist pivotal movement of the blade unit about the longitudinal pivot axis. A spring element may be provided on one or each of the blade unit engaging portions for acting on the blade unit to resist pivoting about the longitudinal axis, but according to a preferred construction a spring element is carried by the interconnecting strut member. The spring element may consist of a leaf spring element positioned for bearing on the underside of the blade unit, and the spring element can be conveniently moulded integrally with the part, e.g. an engaging portion or the strut member, of the blade unit engaging section from which it extends.
According to another aspect, the invention resides in a support structure for mounting an elongate blade unit to a handle in a safety razor, the structure comprising a hub for attachment to the handle and a pair of arms extending symmetrically from the hub to respective blade unit engaging portions, each arm comprising a substantially rigid beam member having first and second ends respectively resiliently hingedly coupled to the hub and to the respective blade unit engaging portion, thereby to permit displacement of the engaging portions towards the handle in a predetermined movement plane, the arms restraining displacement of the engaging portions in directions transverse to said movement plane.
The beam member of each arm is preferably resiliently hingedly coupled to the hub and/or the respective engaging portion by a resiliently flexible arm portion which can be conveniently formed integrally with the beam member. According to a currently preferred construction each arm has the beam member and two resiliently flexible leaf spring portions interconnected substantially in Z configuration. In order to obtain an especially beneficial spring reaction characteristic in response to blade unit displacement, the leaf spring portions of each arm converge in a direction towards the blade unit, and in particular towards the blade unit engaging portion to which that arm is connected. Firm support against displacement of the blade unit transversely to the movement plane can be achieved by arranging each leaf spring portion to lie substantially in a plane which is substantially perpendicular to the movement plane, with the leaf spring portions of each arm converging to a point on the pivot axis where drag forces are delivered by or received from the blade unit during shaving. With the leaf spring portions so arranged, their respective longitudinal torsional axes are convergent toward points where drag loads can be resolved as being imparted, and with the points of convergence associated with the respective arms spaced apart longitudinally of the blade unit the blade unit is firmly supported against movement transverse to the desired movement plane. Adequate stiffness of the arms in the desired movement direction can be ensured by
Hawes Christopher Martin
Miller Chrispin
Boukus, Jr. Charles P.
Payer Hwei-Siu
The Gillette Company
Tobin Donal B.
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