Logarithmic Spiral Cam Closure for Self-Locking and Constant Torque
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Solution Overview
Problem
Existing closure systems lack a self-locking mechanism, experience inconsistent torque, and fail to prevent the strap from completely falling out of the cam assembly when loosened, leading to reduced strength and functionality.
Innovation Solution
A cam assembly and strap-based system utilizing logarithmic spirals for self-locking, with adjustable contact angles and secondary frictional elements like detents, along with a guide component to manage strap engagement and disengagement, ensuring constant torque and preventing strap ejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional closure system is used, then the structure is simple, but the system lacks self-locking mechanism and creates inconsistent torque
Solution Approach 1:
The patent employs a logarithmic spiral geometry in the cam assembly, which is a curved mathematical form that enables self-locking through its inherent geometric properties. The spiral curve creates variable contact angles that automatically lock the strap in position while maintaining consistent torque throughout the tightening range, resolving the contradiction between reliability and complexity.
Solution Approach 2:
The invention changes the geometric parameters of the cam assembly by using a logarithmic spiral instead of traditional straight or circular cam profiles. This parameter change in the cam geometry enables the self-locking mechanism and constant torque characteristics without requiring additional complex components.
2Productivity
If the contact angle between cam and strap is increased for rapid tightening, then the tightening speed improves, but the self-locking capability is reduced
Solution Approach 1:
The logarithmic spiral geometry inherently provides the optimal balance between contact angle and self-locking capability. The curved spiral profile maintains a consistent contact angle relationship that enables both rapid tightening and reliable self-locking simultaneously, eliminating the need to trade off between these competing requirements.
3Adaptability or versatility
If the cam assembly allows free strap movement for easy adjustment, then the adaptability improves, but the strap may completely fall out when loosened
Solution Approach 1:
The logarithmic spiral cam assembly provides self-retention of the strap through its geometric properties. As the strap is loosened, the spiral geometry naturally guides and retains the strap within the cam assembly, preventing it from completely falling out while maintaining infinite adjustability. The system serves itself by using the spiral geometry to automatically retain the strap without requiring additional retention mechanisms.
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 system provides a self-locking, infinitely adjustable closure with consistent torque, enhanced strength, and rapid release/insertion capabilities, preventing strap ejection and managing overloading forces effectively.
Implementation Method 1
One or more logarithmic spirals cause the strap pins to always be engaged at a constant angle, often self-locking. In addition, secondary frictional elements, for example detents on the bottom or periphery of the cam or buttons, may be used to make the system self-locking
Data Source
AI summary
In some embodiments, a cam assembly and strap based closure system using a spiral is configured for bringing two sides of an article together. In some embodiments, when the user inserts the strap into the cam assembly and turns a knob, the strap is driven into the cam assembly and the strap pins engage one or more cam spirals. In some embodiments, the system is configured such that strap pins may be engaged at a constant angle which may be self-locking. In some embodiments, the system may be infinitely adjustable and the torque felt by the knob may be constant. In some embodiments, the system may be configured to be a quick release system and may allow rapid insertion of the strap for faster operation.