Variable Resistance Device Cam Profile Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional resistance devices, such as spring-based and rubber-based exercisers, generate resistance forces that are either logarithmic or linear, which do not match the variable force profile of a healthy human hand, and conventional clamps and centering mechanisms fail to apply specific force profiles, leading to inconsistent or damaging applications.
Innovation Solution
A variable resistance device comprising a resiliently deflectable beam and a cam system that generates a variable resistance force by shifting an interface element along a cam surface with a varying profile, allowing for customizable resistance profiles based on the application, such as hand exercisers, shaft centering, and clamping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional spring-based or rubber-based exercisers are used, then resistance force is generated, but the force profile is logarithmic or linear which does not match the variable force profile of a healthy human hand
Solution Approach 1:
The cam surface is designed with a variable profile that changes the mechanical advantage dynamically throughout the range of motion. As the cam follower traverses the cam surface, the radius of curvature varies, creating regions of higher and lower mechanical advantage that correspond to the variable force capabilities of a healthy human hand across different joint angles.
Solution Approach 2:
The invention changes the geometric parameter of the cam surface profile to achieve variable resistance. By carefully designing the cam surface curvature at different positions, the mechanical advantage parameter is modulated to match the physiological force profile of the hand, transitioning from linear/logarithmic resistance to a biologically optimized variable resistance pattern.
2Reliability
If conventional clamps and centering mechanisms are used, then positioning or clamping is achieved, but excessive forces are applied causing damage
Solution Approach 1:
The cam mechanism provides dynamic force modulation during the clamping or centering operation. The variable profile allows the mechanism to apply higher forces when needed for positioning while automatically reducing forces in regions where excessive pressure could cause damage, enabling reliable operation without material harm.
Solution Approach 2:
By varying the cam surface profile parameters, the mechanical advantage is adjusted throughout the operation cycle. This enables precise control of the clamping force parameter, applying sufficient force for effective positioning while preventing excessive forces that would cause damage to the workpiece or mechanism components.
3Adaptability or versatility
If a variable profile cam surface is used to generate irregular resistance force, then the resistance matches human hand mechanical advantage, but the device complexity increases
Solution Approach 1:
The cam surface can be designed as a composite of multiple circular arcs or curve segments, each with specific radius and position parameters. This segmentation approach allows the complex variable profile to be constructed from simpler geometric elements that are easier to manufacture while still achieving the desired irregular resistance force pattern.
Solution Approach 2:
The invention achieves variable resistance by changing the geometric parameters of the cam surface profile. By carefully selecting and varying parameters such as radius of curvature, arc length, and position of different cam surface segments, the irregular resistance force pattern is generated without requiring overly complex manufacturing processes.
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
The device provides a resistance force that varies irregularly, matching the mechanical advantage of a human hand throughout its range of motion, minimizing trauma and accommodating varying physical capabilities, and optimizes shaft centering and clamping forces to prevent damage.
Implementation Method 1
a resiliently deflectable beam... Shifting of the interface element along the cam surface results in corresponding bending of the beam and consequent generation of a resistance force by the beam
Data Source
AI summary
A variable resistance device includes first and second body elements and a force-generating system disposed therebetween. The force-generating system includes a resiliently deflectable beam extending relative to the first body element and toward the second body element, an interface element, and a cam projecting relative to the second body element and toward the first body element. The cam presents a cam surface. The interface element shifts along the cam surface upon application of a driving force to at least one of the body elements relative to the other and consequent shifting of the body elements relative to each other, resulting in corresponding bending of the beam and consequent generation of a resistance force by the beam. The cam surface presents a profile that varies along a length thereof, such that the resistance force generated by the beam varies irregularly as the interface element moves along the cam surface.