Razor Cartridge Pivot Axis Relocation for Erratic Movement Control
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Solution Overview
Problem
Existing wet shave razors experience erratic pivoting of the razor cartridge due to unintentional forces and frictional issues, leading to loss of contact with the shave surface, especially when shaving intricate details.
Innovation Solution
A shaving implement with a razor cartridge that pivots about an axis parallel to and aft of the razor blades, featuring a biasing member and a bridge that allows the cartridge to maintain steady positioning by buffering forces and providing flexibility, with the pivot axis relocated under the cap for improved control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the pivot axis is located in the area of the guard, then the razor cartridge can pivot to accommodate surface elevations and depressions, but the razor cartridge tends to pivot erratically and lose contact with the shave surface
Solution Approach 1:
The patent relocates the pivot axis from a forward position (in the guard area) to a rearward position (aft of the razor blades, near the cap). This spatial repositioning in the longitudinal dimension changes the lever arm geometry, reducing the tendency for erratic pivoting while maintaining the ability to follow surface contours. The rearward pivot axis creates a more stable fulcrum that resists unintentional forces better than a forward pivot axis.
2Manufacturing precision
If the user presses the razor harder against the skin to trim intricate details, then trimming precision improves, but the razor cartridge rotates away from the surface and loses contact
Solution Approach 1:
By moving the pivot axis rearward to a position aft of the razor blades, the patent changes the moment arm geometry. This positioning reduces the rotational moment generated by cutting forces on the hair, preventing the cartridge from rotating away from the surface during hard pressing. The new pivot location creates a more favorable mechanical advantage that maintains blade contact even under increased user pressure.
Solution Approach 2:
The bridge structure acts as an intermediary mechanical element between the handle and the razor cartridge. It provides a stable mounting for the rearward pivot axis and transmits forces in a way that supports the cartridge against rotation away from the surface. The bridge serves as a structural mediator that enables the pivot axis relocation to effectively counteract the rotational forces generated during intricate detail trimming.
3Reliability
If a biasing member is used to limit unintentional pivotal movement, then pivot control improves, but the system becomes subject to multiple interacting factors that exacerbate the problem
Solution Approach 1:
The patent addresses the pivot control problem primarily through geometric redesign rather than relying on biasing members. By relocating the pivot axis to a rearward position, the system inherently reduces erratic pivoting through improved leverage geometry. This dimensional change in pivot location reduces dependence on biasing members and their complex interactions with user pressure, hair density, and moisture, thereby reducing device complexity while maintaining reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances control and quality of the shave by reducing erratic movements and maintaining consistent blade contact with the skin, reducing chatter and ensuring precise positioning during fine detailing.
Implementation Method 1
a biasing member extending from the handle and in contact with the razor cartridge... The biasing member extending from the handle is in contact with the razor cartridge to urge the razor cartridge toward the neutral position
Implementation Method 2
Another cause is generally due to frictional forces caused by the surface being shaved passing over the guard bar
Data Source
Figure 1
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AI summary
A shaving implement (10) includes a handle (12) ; a razor cartridge (14) pivotally connected thereto; a biasing member extending from the handle and contacting the razor cartridge; and a bridge (20) pivotally connected to the razor cartridge (14) and slidably connected to the handle (12) . The razor cartridge (14) includes one or more razor blades (16) and a cap (18) located aft of the blades. The razor cartridge (14) is pivotally connected to the handle (12) such that the cartridge pivots about an axis (A) that is generally parallel to and aft of the razor blades (16) , the cartridge (14) being pivotable between a neutral position and a rotated position. The biasing member (15) extending from the handle is in contact withc the razor cartridge (14) to urge the cartridge toward the neutral position. The bridge (20) is slidable between a first position when the razor cartridge is in the neutral position and a second position when the cartridge (14) is in the rotated position.