BLADE ASSEMBLY

Abstract: A blade assembly (10) comprises first and second blades (24) and (24′) which are pivotally mounted to the rest of the assembly (10). This enables the span of each blade to be altered in response to the amount of shaving force generated by the user.

Description: This invention relates to a blade assembly. More specifically the invention relates to a dynamic shaving system and particularly a shaving system in which the span of the blade changes with forces exerted during shaving. It has long been recognized that shaving a flexible complex surface like the face with an immovable system such as the conventional razor produces nicks, cuts and lack of uniformity of shaving due to the varying face profile of the shaver. Closeness of the shave is dependent upon, among other factors, the angle of contact between face and blade as well as the flow of skin immediately preceding contact with the blade. One of the factors controlling this flow of skin is the distance between the blade edge and the surface of the blade assembly which contacts the face immediately prior to the blade edge. This distance is measured by the tangential line between the face engaging points of the blade and the leading surface, and is known as span. In a two blade system, each blade has a separate span. The leading or bottom blade has a span determined by the tangent line drawn between its edge and the leading edge of the guard bar which is part of the razor frame and designed to, at least in part, direct skin flow to the blade. The second blade has a span measured by a tangent line drawn between the first and second blade. In the case of the two blade system the first or bottom blade determines the skin flow to the second blade. Several attempts have been made in the past to control the shaving properties of the blade assembly by providing the blade assembly with flexible or movable components in various combinations. US-A-4,516,320 discloses a blade assembly with flexible blades and spacer which move downward in response to shaving forces and a guard bar which flexes inward and upward. US-A-4,443,939 describes a blade assembly in which a cap and guard bar as well as blades and spacer are flexible and tend to conform to the facial curves of shaving pressures applied. US-A-4,069,580 and US-A-4,409,735 disclose a flexible razor produced by utilizing a flexible guard bar and flexible cap as well as flexible blades and spacers. A series of ten patents issued to Chester F Jacobson of which US-A-4,587,729 is the latest, describe a blade assembly with blades which are individually biased and move linearly reciprocally in response to shaving forces. In several of these patents, the same type of movement is disclosed for a guard bar. In EP-A-45879 there is disclosed a razor blade assembly having the features of the precharacterising clause of Claim 1. According to one aspect of the present invention there is provided a blade assembly comprising a blade supporting means for supporting first and second blades, and a guard bar, said blade supporting means comprising a first blade support adapted to support the first blade and a second blade support adapted to support the second blade characterised in that the blade supporting means further includes a frame with a substantially flat bottom portion, a front portion and a back portion both portions extending upward from said bottom portion, a hollow central portion defined at either side by inner faces of said front and back portion, and said front portion includes the guard bar which is formed on the top of said front portion, said first blade support is mounted on said bottom portion and extends upward to support said first blade, said blade support including pivoting means including a finger portion to which said first blade is securely attached which allows pivotal movement of the first blade along a predetermined path in a direction towards the back portion and reversely to change the span of said first blade in response to pressures exerted during shaving, and said second blade support is mounted on said bottom portion and extends upward to support said second blade, second blade support including pivoting means including a finger portion to which said second blade is securely attached which allows pivotal movement of the second blade along a predetermined path in a direction towards the back portion and reversely to change the span of the second blade independently of the change in span of the first blade. Preferably the fingers are adapted to bias the blades to a predetermined position, preferably a position at which the span is a minimum. Preferably the shaving edges are substantially parallel to one another when not subjected to shaving forces. Desirably the blades are mounted on the blade supports by staking. In one embodiment a first and second stop depend from the sides of said frame to limit pivotal movement of said first and second blades. The first and second stops may limit the minimum span of the blades. Advantageously, the first and second blade supporting means includes a leaf spring projecting upwardly from the bottom portion. Advantageously also, the span of the first and second blade can vary between substantially 0.040 in. (0.1 cm) and substantially 0.090 in. (0.229 cm) in response to shaving pressure. In addition, at least one further stop may extend from said bottom of said frame to surround a major portion of the length of each of said leaf springs. The or each further stop may comprise an abutment provided on a shoulder which mounts the leaf springs to the bottom portion of the frame. The or each further stop may also limit the maximum span of the blades. The finger portions are preferably L-shaped. Furthermore, the finger portions preferably have reduced width portions forming the leaf springs which connect the blade supporting means to the frame. Reference is now made to the accompanying drawings, in which:- Figure 1 is a side view of a blade assembly according to the invention partially in cross-section; Figure 2 is a top plan view of the blade assembly shown in Figure 1; and Figure 3 is a side view partially in cross-section of the blade assembly shown in Figures 1 and 2. In the drawings a razor blade assembly 10 is mounted upon a handle 19. The blade assembly 10 has razor blade supporting means in the form of a frame comprising a bottom portion 14, a front portion 15 and a back portion 12 with both the front and back portions 15 and 12 upstanding from the bottom portion 14. The frame further includes an upper portion 13 which extends from the front portion 15 to the back portion 12. First and second stops 16 and 16′ extend outward from opposite side portions 17. The blade supporting means also includes first and second blade supports in the form of fingers 21 and 21′; razor blades 24 and 24′ are mounted on the fingers 21 and 21′ resepectively by means of stakes 25 and 25′. The fingers 21 and 21′ are connected to the bottom portion 14 by means of leaf springs 22 and 22′. The movement of the leaf springs 22 and 22′ is restricted by matching shoulders 23 and 23′ which extend upward from the bottom portion 14. The leaf spring 22 is allowed to flex to "open" the space between guard bar 18 and blade 24; this is shown in Figures 1 and 2. The leaf spring 22′ is allowed to flex to "open" the space between the blades 24 and 24′; this is shown in Figure 3. Conventionally, razor spans for each blade tend to vary between 0.040 in. (0.1 cm) and 0.065 in. (0.165 cm) depending upon the desired predetermined setting. According to a preferred embodiment of this invention each individual span can vary between substantially 0.040 in. (0.1 cm) and substantially 0.090 in. (0.229 cm) in response to the pressure exerted during shaving. The pressure acts sequentially against the first blade 24 and then the second blade 24′ to increase the distance of the span by exerted forces against the biasing action of the springs 22 and 22′. As can be seen by reference particularly to Figures 2 and 3, each of the blades 24 and 24′ are held in place by the stakes 25 and 25′ which extend to the underlying fingers 21 and 21′. The blades 24 and 24′ are staked separately. It should be noted that a razor cap is not shown in Figure 2, but that with both blades 24 and 24′ closed, the plan view of the razor shown in Figure 2 is similar to others currently available. As shown in Figure 2, the guard bar 18 extends toward the blades 24 and 24′ and is connected to the bottom portion 14 by means of ribs 26. While only a single embodiment is depicted in the drawings, variations will readily suggest themselves to those skilled in the art. For example, a conventional spacer can be used as stop 16′ for maintaining the minimum span of second blade 24′. Also, the shoulders 23 and 23′ can be extended to form abutments for fingers 21 and 21′ to control the span. In particular, the abutments may limit the maximum span of the blades 24 and 24′. It should be noted that in response to shaving pressure the blades move only toward the rear to expand the span and return to their original non-pressured position in the forward direction after shaving forces have been removed. This invention, therefore provides a simple mechanical means of altering the skin flow of each blade of a multi-blade system in response to pressure during shaving generated by the user. The razor shown in the drawings is a disposable razor in which the razor blade assembly 10 is integral with the handle. However, the present invention is equally applicable to blade assemblies in the form of cartridges which can be removed from the handle.

Claims: A blade assembly (10) comprising a blade supporting means for supporting first and second blades (24,24'), and a guard bar (15), said blade supporting means comprising a first blade support adapted to support the first blade (24) and a second blade support adapted to support the second blade (24'), characterised in that the blade supporting means further includes a frame with a substantially flat bottom portion (14), a front portion (15) and a back portion (12) both portions extending upward from said bottom portion (14), a hollow central portion defined at either side by inner faces of said front and back portion (15,12), and said front portion (15) includes the guard bar which is formed on the top of said front portion, said first blade support is mounted on said bottom portion (14) and extends upward to support said first blade (24), said blade support including pivoting means including a finger portion (21) to which said first blade (24) is securely attached which allows pivotal movement of the first blade (24) along a predetermined path in a direction towards the back portion (12) and reversely to change the span of said first blade in response to pressures exerted during shaving, and said second blade support is mounted on said bottom portion (14) and extends upward to support said second blade (24'), second blade support including pivoting means including a finger portion (21') to which said second blade (24') is securely attached which allows pivotal movement of the second blade (24') along a predetermined path in a direction towards the back portion (12) and reversely to change the span of the second blade (24') independently of the change in span of the first blade (24). A blade assembly (10) according to Claim 1 characterised in that the shaving edges of the blades (24,24') are substantially parallel to each other when not subjected to shaving forces. A blade assembly (10) according to Claim 1 or Claim 2 characterised in that the blades (24,24') are mounted on said blade supports by staking (25,25'). A blade assembly (10) according to any preceding claim characterised in that a first and second stop (16,16') depend inward from the sides of said frame to limit pivotal movement of said first and second blades (24,24'). A blade assembly (10) according to any preceding claim, characterised in that the first and second blade supports each include a leaf spring (22,22') projecting from the bottom portion (14). A blade assembly (10) according to Claim 5 characterised in that stops (23,23') extend from said bottom portion (14) of said frame to surround a major portion of the length of each of said leaf springs (22,22'). A blade assembly (10) according to any preceding claim, characterised in that the span of said first blade (24) and the span of said second blade (24') can vary between substantially 0.040 in. (0.10 cm) and substantially 0.090 in. (0.229 cm) in response to shaving presssure. A blade assembly (10) according to any preceding claim, characterised in that the finger portions (21,21') have reduced width portions forming leaf springs (22,22') which connect the blade supporting means to the frame. A blade assembly (10) according to any preceding claim characterised in that the finger portions (21,21') are L-shaped.

Inventors: FERRARO, FRANK A.
Applicants: WARNER-LAMBERT COMPANY
Application year: 1987
Main classification: B26B21
IPC codes: B26B21