Nested Elastic Cord for Pull Exerciser Safety
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Solution Overview
Problem
Conventional elastic cords in pull exercisers can break during use, causing injury to the user.
Innovation Solution
An elastic cord design featuring a hollow outer cord with a rib that encloses an elastic string, where the string's maximal elongation is greater than the cord's, preventing injury by retaining the cord and allowing it to stretch without breaking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional hollow elastic cord is used in a pull exerciser, then the device is light and easy to carry, but the elastic cord may break during use and injure the user
Solution Approach 1:
The patent implements a nested structure where an inner elastic cord is placed inside an outer elastic cord. When the outer cord breaks, the inner cord continues to provide elastic function and prevents the broken outer cord from injuring the user. This nesting arrangement resolves the contradiction by ensuring reliability through the inner cord while maintaining the light and portable design of the overall exerciser.
Solution Approach 2:
The patent applies beforehand cushioning by having the inner elastic cord ready to compensate when the outer cord breaks. The inner cord acts as a pre-prepared safety mechanism that cushions against potential injury from the broken outer cord, thus resolving the contradiction between light design and injury prevention.
2Reliability
If the elastic cord is made with higher strength to prevent breakage, then reliability improves, but the device becomes heavier and less portable
Solution Approach 1:
The nested dual-cord structure allows each individual cord to be lighter while the combination provides the required reliability. The inner cord serves as a lightweight backup that ensures safety without requiring the outer cord to be excessively strong and heavy.
Solution Approach 2:
The patent changes the parameter approach from using a single heavy high-strength cord to using two lighter cords with different properties. The inner cord has higher elasticity and the outer cord provides initial strength, together achieving the reliability of a single strong cord while reducing overall weight.
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 elastic string prevents injury by maintaining stretchability and restraining the broken cord, reducing the likelihood of further breakage and ensuring safe operation.
Implementation Method 1
An elastic string is received in the longitudinal hole of the rib. The elastic string includes two ends respectively located in the first and second ends of the hollow outer elastic cord. The elastic string has a maximal elongation larger than a maximal elongation of the hollow outer elastic cord.
Data Source
AI summary
An elastic cord includes a hollow outer elastic cord having a first end and a second end spaced from the first end in a longitudinal direction. The hollow outer elastic cord further includes an outer periphery and an inner periphery spaced from the outer periphery in a radial direction perpendicular to the longitudinal direction. A rib extends from the inner periphery. The rib extends from the first end through the second end of the hollow outer elastic rod. The rib includes a longitudinal hole extending from the first end through the second end of the hollow outer elastic cord. An elastic string is received in the longitudinal hole of the rib. The elastic string includes two ends respectively located in the first and second ends of the hollow outer elastic cord. The elastic string has a maximal elongation larger than a maximal elongation of the hollow outer elastic cord.