Drawstring Winding Device with Single Elastic Pawl
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Solution Overview
Problem
Existing winding and locking devices for drawstrings in personal equipment, such as clothing and shoes, face challenges with fragility and complexity, particularly due to the close placement of locking and unlocking surfaces, which makes them prone to breakage under high tension and difficult to loosen.
Innovation Solution
A device with a single pawl featuring a retention portion and an actuation portion on separate bars, allowing for elastic deformation to disengage the retention portion from a complementary relief, distributing forces over a larger surface area and providing a lever arm for easy unlocking, while also incorporating a noise element for user feedback during loosening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If locking and unlocking surfaces are placed close to each other, then the device structure is compact, but the device becomes fragile and prone to breakage under high tension
Solution Approach 1:
The patent separates the locking and unlocking surfaces along the axial dimension of the pawl rather than placing them close together in the same plane. The locking surface is positioned at one end of the pawl while the unlocking surface is positioned at the opposite end, utilizing the length of the pawl to distribute stress and prevent breakage while maintaining compact overall device volume.
2Volume of moving object
If locking and unlocking surfaces are placed close to each other, then the device structure is compact, but the device becomes difficult to loosen requiring high torque
Solution Approach 1:
By positioning the unlocking surface at the free end of the pawl opposite to the locking surface, the patent creates a long lever arm that extends radially outward. This dimensional arrangement provides mechanical advantage, allowing the user to apply loosening force at a greater distance from the rotation axis, thereby reducing the torque required to overcome the locking engagement.
3Reliability
If multiple engagement rods are used, then rotation retention forces are distributed, but the device construction becomes complex and hyperstatic
Solution Approach 1:
The patent extracts and eliminates the redundant engagement rods from the device, retaining only a single pawl element. The single pawl incorporates both locking and unlocking surfaces positioned at opposite ends, which simplifies the construction while maintaining reliable rotation retention through the strategic geometric arrangement of the remaining component.
4Reliability
If a spring is added to push the pawl into position, then the pawl positioning is improved, but the device becomes more complex and heavier
Solution Approach 1:
The patent designs the pawl with inherent geometric features including inclined locking and unlocking surfaces that enable automatic self-positioning and self-latching. The pawl naturally engages with the ratchet teeth through its own geometry without requiring external springs or additional positioning mechanisms, thereby maintaining construction simplicity while ensuring reliable positioning.
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 enhances mechanical strength, reduces wear, and simplifies the design, enabling faster and more resistant tightening while allowing for easy and precise loosening, even under high tension, with improved user feedback during the loosening process.
Implementation Method 1
a first bar (610) carrying the retention portion (611), the first bar being elastically deformable in order to cause, when deformed, the disengagement of the retention portion of said at least one complementary relief
Data Source
Figure 1
Figure 2~4
Figure 3
AI summary
The invention relates to a winding and locking device (100) for a shoelace comprising a fixed support (200), a rotating spool (300), a wheel (500) for driving the spool (300) operable by a user and locking elements (210, 600) for the spool (300).The locking elements (210, 600) comprise at least one ratchet (600) having: a retention portion (611) engaging at least one additional relief (210) of the support (200) in the absence of a rotational force exerted by the user on the knob (600); a base (614) driven in rotation when the knob (500) turns in loosening; a first bar (610) carrying the retention portion (611) and elastically deformable; an actuating portion (622) carried by a second bar (620) and away from the retention portion (611); the ratchet (600) being configured so that, during loosening, the knob (500) by the actuating portion (622) disengages the retention portion (611).