Retractable Leash Hinge Joint Progressive Braking
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Solution Overview
Problem
Conventional retractable leashes cause sudden and harsh stops for pets, leading to potential injuries for both the animal and the user, and are prone to mechanical failures due to complex internal mechanisms.
Innovation Solution
A retractable leash assembly with a handle attached by a hinge joint, featuring a braking device that actuates a braking action proportionally with the pulling force, utilizing a spur gear system or friction brake to slow down the lead line unwinding speed, and an instant-stop brake for emergency situations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a sudden brake appliance is used to stop the spool quickly, then the braking response speed is improved, but the dog and user are subjected to harsh stopping forces that can cause injuries
Solution Approach 1:
The brake appliance transitions from a static sudden-stop mechanism to a dynamic progressive-braking system. The braking force increases progressively as the spool rotates, transforming the harsh sudden stop into a gentle controlled deceleration that protects both the dog and user from injuries while maintaining effective braking response.
Solution Approach 2:
The braking action is applied periodically through the rotation of the spool, with the brake contact engaging and disengaging in a controlled manner. This periodic engagement creates a progressive braking effect that distributes the stopping force over time, avoiding the concentrated harsh force of a sudden brake while maintaining effective control.
2Measurement precision
If multiple internal brake appliances are used to control the spool, then the braking control precision is improved, but the device complexity and susceptibility to mechanical damage increase
Solution Approach 1:
The invention extracts and simplifies the braking mechanism by using a single brake appliance instead of multiple complex internal mechanisms. This simplified design reduces the number of vulnerable parts while maintaining precise braking control through the progressive engagement of the brake contact with the spool during rotation.
Solution Approach 2:
The brake appliance is designed to engage automatically through the rotational motion of the spool itself, eliminating the need for complex control mechanisms. The rotation of the spool naturally brings the brake contact into engagement, allowing the system to control braking through its own operational motion rather than requiring additional actuators or control systems.
3Force
If a friction-based braking action is used, then the braking force is proportional to the pulling force, but the braking efficiency may be insufficient for sudden stops
Solution Approach 1:
The friction-based brake is enhanced with dynamic engagement through spool rotation. As the spool rotates during pulling, the brake contact progressively engages with increasing friction force, allowing the system to provide proportional braking force for normal operation while achieving high braking efficiency for sudden stops through the rotational engagement mechanism.
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 gentle control of the pet's pulling force, reducing the risk of injuries and mechanical failures, allowing for efficient training and safer use while maintaining durability and cost-effectiveness.
Implementation Method 1
a spring-loaded spool with a cord or a flat band wound around the spool
Implementation Method 2
a friction-based braking action is initiated by a user by pressing a push button. Braking efficiency is thus proportional to the force exerted (by the user) on the push button
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
A retractable leash assembly (10) for a pet animal, such as a dog, is provided. The leash assembly comprises a casing body (1) with a handle (2) attached to the body by an at least one hinge joint (11), a braking device, and a spool arrangement (4) with an extendable lead line (3) wound thereabout and configured attachable to the pet animals' collar or harness, wherein in said leash assembly the handle is configured to articulate about the joint (11) with regard to the casing body (1), said articulation movement of the handle (2) being triggered by the pulling force exerted on the lead line (3) by the animal kept on the leash, and wherein, by virtue of said articulation movement the braking device (6) actuates a braking action causing the lead line (3) to reduce unwinding speed proportionally with an increase in the pulling force.