Retractable Animal Leash With Emergency Manual Rewind Mechanism
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Solution Overview
Problem
Existing retractable animal leash devices are difficult to manually retract safely and quickly in emergency situations, often requiring complex operations or risking injury to the owner.
Innovation Solution
A retractable leash device with a second handle and mechanical coupling to the spool, allowing for intuitive and automatic manual retraction of the leash, featuring a control mechanism with multiple modes for normal use, emergency retraction, and leash length setting, including a ratchet pawl mechanism for secure winding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the owner manually retracts the leash by reducing pulling force, then the leash can be retracted, but it requires complex cyclic operation of the brake and synchronisation, becoming difficult or impossible if the dog is continuously pulling
Solution Approach 1:
The device is segmented into two independent spools: a first spool for normal leash operation and a second spool for emergency retraction. Each spool has its own brake mechanism, allowing independent operation. The second spool can be engaged to provide emergency retraction without interfering with normal leash function, simplifying the operation by dividing the complex brake synchronisation task into separate, manageable operations.
Solution Approach 2:
A control mechanism acts as an intermediary between the owner and the brake systems. This control mechanism includes a control element that can selectively engage or disengage the second spool's brake, and a coupling mechanism that connects the second spool to the first spool. This intermediary system automates the complex brake synchronisation by providing controlled mechanical coupling between the two spools during emergency retraction.
2Speed
If the owner directly grasps the exposed leash between the handle and the dog, then the leash can be retracted quickly, but it is dangerous and may result in injury to the owner such as friction burns
Solution Approach 1:
The second spool and its associated cord act as an intermediary mechanism between the owner and the dog. Instead of directly grasping the exposed leash, the owner operates the second spool's brake to retract the leash through this intermediate mechanical system. The cord on the second spool provides a safe handling interface that eliminates direct contact with the tension-loaded exposed leash, preventing friction burns while enabling quick retraction.
3Adaptability or versatility
If the spool is free to rotate in both wind and unwind directions, then the dog can roam freely, but the leash cannot be manually retracted
Solution Approach 1:
The device segments the spool system into two independent spools with independent brake controls. The first spool maintains free rotation in both directions for normal dog roaming, while the second spool provides a separate mechanism for manual retraction. This segmentation allows the system to maintain adaptability for dog roaming while adding manual retraction capability without restricting normal operation.
Solution Approach 2:
The control mechanism dynamically adjusts the system configuration by selectively engaging or disengaging the second spool's brake through the control element. When manual retraction is needed, the control element engages the second spool's brake, creating a dynamic change in the system state that enables retraction while maintaining normal roaming freedom when the control element is disengaged.
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
Enables safe and quick manual retraction of the leash without putting down the leash, reducing the risk of injury and allowing for intuitive operation, even when the dog is continuously pulling, by providing a spring-loaded pull handle and a control mechanism that automatically sets the device to emergency mode.
Implementation Method 1
The leash may be unwound by the animal by pulling on the leash, and rewound by the action of a spring when the pulling force exerted by the dog is less than that of the spring
Implementation Method 2
The control mechanism for the spool comprises a ratchet pawl for engaging with ratchet teeth of the spool
Data Source
Figure 1
Figure 2
Figure 3(a)~3(b)
AI summary
A retractable leash device has a first handle (12) for holding the device, a spool (30) and a leash (14) wound on the spool (30). There is a spring-based rewind mechanism for the leash. A second handle (18) is provided for manually retracting the leash. A mechanical coupling between the second handle (18) and the spool (30) provides a second rewind mechanism for the leash. This second rewind mechanism is used to pull an animal back toward the owner in a safe and convenient way.