Strap Adjustment System with Adjustable Friction Protrusion
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Solution Overview
Problem
Strap adjustment systems often struggle to keep the strap in place before locking, especially in inconvenient locations or when using only one hand, due to insufficient friction, making it difficult to position the strap correctly.
Innovation Solution
A strap adjustment system with an adjustable height component that adds friction underneath the strap, utilizing a screw disc with a central protrusion and screw threads to control friction levels, combined with a cam lid and torsion spring for automatic closure, allowing fine-tuning of sliding speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the strap is allowed to slide freely through the system with little friction in an unlocked state, then the strap can be easily released, but it becomes difficult to position the strap in the proper setting
Solution Approach 1:
The patent implements a dynamic friction control mechanism where the cam member can be in different states (engaged or disengaged). When disengaged, the strap slides freely for easy release. When engaged, the cam member applies friction to the strap to enable precise positioning. This dynamic state change allows the system to adapt between the two contradictory requirements of easy release and precise positioning.
Solution Approach 2:
The patent changes the friction parameter between two states by using the cam member's position. In the unlocked state, friction is minimized allowing free sliding. In the adjustment state, the cam member engages to increase friction and provide tactile feedback for precise positioning. This parameter change resolves the contradiction by providing different friction levels based on operational needs.
2Ease of operation
If the system is located in an inconvenient place or the user has only one hand, then the user has limited control, but the strap still needs to be positioned accurately
Solution Approach 1:
The cam member is designed to be actuated by the strap itself during the adjustment process. As the strap is pulled through, the cam member automatically engages and disengages, providing self-service adjustment functionality. This reduces the manual dexterity required while maintaining positioning precision through the mechanical action of the cam-strap interaction.
Solution Approach 2:
The interaction between the cam member's cam surface and the strap creates a tactile feedback mechanism that provides vibratory or tactile sensation to the user during adjustment. This mechanical feedback allows the user to sense the proper positioning point even with limited manual control, thereby maintaining positioning precision while enabling one-handed or difficult-to-reach operation.
3Reliability
If a hinged element is used to hold the strap in place via friction, then the strap can be secured, but the friction is not adjustable and may be insufficient
Solution Approach 1:
The patent transforms the static friction mechanism into a dynamic one by introducing the cam member that can adjust its engagement level. The cam member's position can be varied to change the friction applied to the strap, allowing the system to adapt between different holding reliability levels based on the specific application requirements.
Solution Approach 2:
The patent segments the friction-generating function into two separate components: the hinged element that provides base friction and the cam member that provides adjustable friction. This segmentation allows each component to be optimized for its specific function while collectively providing both reliable holding and adaptable friction levels.
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 effectively keeps the strap in place by adjusting friction levels, slowing down sliding and enabling precise adjustments, even under heavy loads, improving usability for applications like backpack shoulder straps.
Implementation Method 1
a screw disc having a central protrusion and screw threads extending around the central protrusion. The central protrusion fits through the aperture in the base body by rotating the screw disc so that the threads in the screw disc mate with the threads in the aperture
Implementation Method 2
the protrusion has a rounded top surface with ridges for creating friction against a strap when the strap extends through the base body
Implementation Method 3
The cam lid can be held in a lowered position by a torsion spring to eliminate the need for manual closing of the cam lid
Implementation Method 4
the bottom surface containing friction-creating elements configured for gripping a strap placed through the base body when the cam lid is lowered
Data Source
Figure 1A~1B
Figure 2~3
Figure 4~6
AI summary
A strap adjustment system has a base body having a bottom wall, two side walls and a strap retaining bar extending between the two side walls, the bottom wall having an aperture therethrough with screw threads extending around an inside surface, and a screw disc having a central protrusion and screw threads extending around the central protrusion. The central protrusion fits through the aperture in the base body by rotating the screw disc so that the threads in the screw disc mate with the threads in the aperture, such that a height of the protrusion above the bottom wall of the base body is adjustable by turning the screw disc. In situations where a high degree of friction is required, the protrusion can be positioned at a maximum height through the aperture, and in situations where a low degree of friction is desired, the protrusion can be positioned lower.