Retractable Leash Spool With Automatic Tension-Based Braking
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Solution Overview
Problem
Existing retractable leashes rely solely on user-applied force for braking, which is inefficient and can cause injury to animals and users due to abrupt jerks when the leash is fully unwound.
Innovation Solution
A retractable leash device with a braking mechanism that automatically brakes the spool body based on leash tension, featuring a brake element that engages via a deflection device to transmit tension and can be manually actuated for additional control, with a brake lever and spring system to manage braking force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a brake switch is used to block further rotation of the spool body, then the animal leash uncoiling is prevented, but the braking effect depends solely on the force applied by the leash holder which is not advantageous
Solution Approach 1:
The braking device is designed to automatically engage and brake the spool body through the brake element and brake force generation mechanism without requiring continuous manual intervention. The system self-regulates the braking force based on the uncoiling state of the animal leash, eliminating dependency on the leash holder's applied force for reliable braking.
Solution Approach 2:
The brake force generation mechanism responds to the uncoiling state of the animal leash, creating a feedback loop where the system automatically adjusts braking intensity based on real-time conditions. This ensures reliable braking action that adapts to varying leash tension and uncoiling rates.
2Adaptability or versatility
If the animal leash is completely uncoiled from the spool body, then the animal can run freely, but an abrupt jerk occurs on the animal's neck and the leash holder's hand which can cause injury
Solution Approach 1:
The braking device is positioned to engage before the animal leash is completely uncoiled from the spool body. The brake element automatically activates to counteract the uncoiling motion at an appropriate moment, preventing the abrupt jerk that would otherwise occur when the leash runs out, thereby eliminating the injury risk while maintaining running freedom.
Solution Approach 2:
The system performs preliminary braking action before the critical moment of complete uncoiling. The brake force generation mechanism activates in advance to control the uncoiling process, ensuring the leash holder and animal avoid the harmful jerk that would occur if braking waited until the leash was fully extended.
3Extent of automation
If the brake element brakes the spool body through automatic braking force generation, then controlled retraction is achieved, but the braking force must be transmitted through the brake deflection device which adds structural complexity
Solution Approach 1:
The brake deflection device serves as an intermediary element that transmits the braking force from the brake element to the spool body. This mediator component enables automatic braking force generation while maintaining a relatively simple overall structure, as it simply channels the force without requiring complex transmission 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 device provides automatic and adjustable braking to prevent leash ends from jerking, ensuring safe and controlled retraction, reducing the risk of injury and enhancing user control over the leash's unwinding.
Implementation Method 1
a return spring (5), wherein the return spring (5) is designed to push the spool body (4) into a coiling position
Implementation Method 2
a brake element (8) designed to brake the rotating spool body (4)
Data Source
AI summary
The invention relates to a retractable leash device (1) for uncoiling and coiling an animal leash (2), wherein the retractable leash device (1) comprises a housing (3), a spool body (4) rotatably mounted on the housing (3) and a return spring (5) which is designed to push back or hold back the spool body (4) into a coiling position in which the animal leash (2) is coiled onto the spool body (4). The spool body (4) can be rotated out of the coiling position against a return force of the return spring (5) for uncoiling the coiled animal leash (2), wherein a braking device (7) comprises a brake element (8) designed to brake the rotating spool body (4), wherein the braking device (7) is designed such that the brake element (8) brakes the spool body (4) as a result of a braking force automatically generated by an animal leash tension in the animal leash caused by the uncoiling of the animal leash (2). The braking device (7) comprises a brake deflection device (11) at which the animal leash (2) is deflected and which is mounted on the housing (3) so as to be movable relative to the spool body (4) and which is designed to transmit the animal leash tension to the brake element (8).