Ring-Shaped Leash Body with Toothed Drum and Spring
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Solution Overview
Problem
Existing leashes for domestic animals have large overall dimensions, a displaced gravity center, and are not suitable for high loads or low-light conditions, with a limited cord length due to the spring mechanism's constraints.
Innovation Solution
A leash with a toothed drum and spiral band spring made of high-carbon alloyed steel, integrated into a ring-shaped body with a handle, allowing cord extension up to 2.5 to 3.5 meters, and incorporating light-reflecting elements for safety, while reducing overall dimensions and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the drum with spring mechanism is installed in a solid body with handle, then the mechanism can be driven by spring, but the overall dimensions become large and gravity center is displaced
Solution Approach 1:
The leash body is divided into a hollow ring-shaped structure with separate compartments for the drum and spring mechanism, allowing the gravity center to be positioned near the handle while maintaining mechanism functionality. The hollow body segments the internal space to accommodate components without increasing external dimensions.
Solution Approach 2:
The spring mechanism is repositioned from a solid body configuration to a hollow ring-shaped body, utilizing the radial dimension of the ring to place the drum and spring in a configuration that maintains compact overall dimensions while balancing the gravity center near the handle.
2Strength
If the drum with spring mechanism is installed in a solid body with handle, then the mechanism can be driven by spring, but the gravity center is displaced towards the operation mechanism area increasing load on wrist
Solution Approach 1:
The hollow ring-shaped body has an asymmetric internal layout where the drum and spring mechanism are positioned to balance the gravity center near the handle rather than at the geometric center, reducing the moment arm and decreasing the load on the user's wrist.
3Force
If the spring mechanism is designed for high loads, then the spring parameters must be increased, but the cord length is limited to 2 meters due to impossibility of installing drum with sufficient parameters
Solution Approach 1:
The drum is nested within the hollow ring-shaped body, and the spring is nested within the drum structure. This nested arrangement allows the drum to have sufficient diameter for high-load spring parameters while the hollow body provides the necessary internal volume without increasing external dimensions, enabling cord lengths of 2.5 to 3.5 meters.
4Reliability
If the cord length is extended to 2.5 to 3.5 meters, then the operational safety is improved, but the spring mechanism dimensions must be increased
Solution Approach 1:
The hollow ring-shaped body segments the internal space to accommodate a larger-diameter drum and extended spring mechanism required for 2.5 to 3.5 meter cord lengths, while the hollow structure prevents external dimension increase, maintaining compact overall size for safe operation.
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 solution provides increased operational safety, reduced load on the wrist, and extended cord length without increasing the leash's size or weight, ensuring reliable and safe use in various conditions.
Implementation Method 1
Inside the toothed drum there is mounted a spiral band spring
Implementation Method 2
the spring being capable of winding the cord having a length of at least from 2.5 to 3.5 meters
Implementation Method 3
The cord is a band that has light-reflecting elements
Data Source
AI summary
The invention relates to extensible leashes for domestic animals comprising a means for blocking extension of a cord (6) and allows the cord (6) to be extended up to a given maximum length in a regulated fashion. The automatically regulated leash for domestic animals that consists of a rind-shaped hollow body (12, 2) with a handle, wherein a winding roll with a cord (6) is mounted, the free end of the cord (6) is outwardly withdrawn through an opening in the body (12, 2), a stop (8) mechanism for the cord (6) that is regulated by a button (7) located on the body (12, 2). According to the invention, length of the cord (6) is from 2.5 to 3.5 meters. The cord (6) is configured to be wound on the roll that is mounted on guides in the body (12, 2) and comprises, on an inner cylindrical surface, teeth that are internally engaged with a toothed drum (4) mounted on the shaft fixedly attached in a cavity of the handle that is made as an elongated protrusion that has an elliptical shape in cross-section and made integrally with the body (12, 2). Inside the toothed drum (4) there is mounted a spiral band spring (5) that is made of a high-carbon alloyed steel having a Mn content of not more than 1.2%, which has a free end that is fixed on the shaft, and another one that is fixed on a lateral inner wall of the drum (4) having an operational stroke range along the diameter of from 4 to 15 mm. Width of the band spring (5) is within 12±5 mm, length in a deployed state is 2500±800 mm, thickness is 0.1±0.03 mm. Therewith, the diameter of the toothed drum (4) is 0.25-0.40 of the diameter of the toothed surface of the winding roll. The cord (6) is a band that has light-reflecting elements. The body (12, 2) and the internal components of the structure are made of ABS-plastic. The body (12, 2) portion that is provided with the opening for withdrawal of the free end of the cord (6) is displaced relative to the central axis thereof, while the center of gravity is located closer to the handle. The hollow ring-shaped body (12, 2) is made from two symmetrical half pieces. The band spring (5) has a high fatigue strength limit.