Retractable Leash Automatic Locking Mechanism
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Solution Overview
Problem
Conventional retractable leashes require manual operation to lock, which can lead to safety issues if the user fails to lock the leash in time, potentially causing injury to the dog or others, especially when the dog rushes suddenly.
Innovation Solution
A retractable leash with automatic locking and unlocking functions, featuring a spool with ratchet teeth, a stopping mechanism biased by a torsion spring, and a manual override button, allowing the leash to automatically lock when the dog rushes and unlock when tension is released, ensuring safety without user intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual button operation is used to lock the leash, then the device complexity is reduced, but the reliability deteriorates because the user may fail to press the button in time when the dog rushes suddenly
Solution Approach 1:
The stopping means is designed to automatically activate itself when the cord is pulled, without requiring user intervention. The second portion of the stopping means abuts against the cord so that tensioning of the cord actuates the stopping means to rotate to the locking position, and untensioning returns it to the unlocking position
Solution Approach 2:
The stopping means is pre-positioned and biased by the biasing means towards the unlocking position. The ratchet teeth on the spool are pre-configured so that when the stopping means rotates to the locking position, it automatically engages with the ratchet teeth to prevent unwinding before the dog can cause harm
2Reliability
If automatic locking mechanism is added to the spool, then the reliability improves by automatically stopping the dog when it rushes, but the device complexity increases due to additional components like stopping means and biasing means
Solution Approach 1:
The stopping means combines multiple functions into a single component: it acts as a brake (first portion engaging with spool and ratchet teeth), a latch (holding the braking position), and is actuated by cord tension (second portion abutting against cord). The biasing means integrates the unlocking function into the same mechanism
Solution Approach 2:
The stopping means serves multiple purposes: it can be actuated automatically by cord tension for safety locking, can be manually actuated by the press button for controlled locking, and automatically returns to unlock when tension is released, providing both safety and usability functions through one component
3Ease of operation
If the stopping means is biased towards unlocking position, then the ease of operation improves by allowing free movement when not in use, but the reliability worsens because the leash may not lock automatically when needed
Solution Approach 1:
The biasing means applies a counteracting force (biasing towards unlocking position) that is overcome by the stronger force of cord tension when the dog rushes. The ratchet teeth provide a mechanical counter-force that prevents the stopping means from returning to the unlocked position once engaged, ensuring the leash remains locked until manually released
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 leash effectively prevents the dog from rushing away by automatically locking when tensioned, enhancing safety by eliminating the need for manual operation and reducing the risk of injury to the dog or others.
Implementation Method 1
The stopping means is rotatable about a rod positioned between the first portion and the second portion of the stopping means; the biasing means is a torsion spring wound around the rod with a first end of the torsion spring abutting against the second portion of the stopping means.
Implementation Method 2
The braking means on the spool is in form of ratchet teeth disposed at an outer perimeter of the spool.
Data Source
AI summary
A retractable leash with automatic locking and unlocking function including a housing, a spool with a cord wound therearound, a braking means, a cord opening, a stopping means and a biasing means. A second portion of the stopping means abuts against the cord in such a way that tensioning of the cord by an external force actuates the stopping means to overcome biasing force of the biasing means to rotate to the locking position, and untensioning of the cord by the external force returns the stopping means from the locking position to the unlocking position. The present invention automatically locks the leash when the dog rushes, thus improving safety of the leash.