Antitheft Wheel Nut Variable Depth Groove Retention
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Solution Overview
Problem
Existing antitheft locking devices for motor vehicle wheels are vulnerable to severe burglary efforts, particularly the forced removal of neutral bushings, and are difficult to assemble without risking damage to components.
Innovation Solution
An antitheft locking device with a bushing that features a groove of variable depth, allowing the retaining ring to be housed without radial clearance, ensuring the bushing can freely rotate and is securely associated with the device, preventing axial withdrawal without causing material deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a steel elastic ring is used to retain the bushing in a circumferential groove, then the bushing can rotate neutrally and prevent easy rotation of the nut or bolt, but the ring can be forcibly removed by inserting a chisel or screwdriver at the bushing base and bashing it with a hammer, leaving the bushing free to axially exit from the device
Solution Approach 1:
The circumferential groove is divided into two distinct portions: a first portion with greater depth and a second portion with lesser depth. This segmentation creates different functional zones - the deeper first portion provides enhanced retention for the elastic ring to resist forced removal, while the shallower second portion allows proper assembly and neutral rotation of the bushing.
Solution Approach 2:
The groove exhibits variable depth along its circumference, creating local quality differences. The first portion has greater depth specifically positioned to maximize retention strength where the elastic ring needs maximum support against burglary attempts, while the second portion has lesser depth to facilitate assembly and maintain rotational freedom.
2Ease of manufacture
If radial clearance is provided in the circumferential groove for mounting the bushing, then the assembly is possible without breakings or permanent deformations, but the retaining ring can slip out from its seat during burglary attempts
Solution Approach 1:
The groove is segmented into two depth portions that work together: the first deeper portion provides the retention security needed to prevent ring slippage during burglary, while the second shallower portion provides the necessary clearance for easy assembly without forceful actions that could cause damage.
Solution Approach 2:
The solution moves from a uniform single-depth groove to a variable-depth groove with axial dimension variation. This dimensional change allows the groove to provide both retention (through the deeper first portion) and assembly clearance (through the shallower second portion) simultaneously.
3Device complexity
If a fixed depth groove is used for the retaining ring, then the structure is simpler, but it cannot simultaneously provide both assembly clearance and burglary resistance
Solution Approach 1:
The groove structure implements local quality by having different depth characteristics in different portions. The first portion has greater depth specifically tailored for burglary resistance, while the second portion has lesser depth optimized for assembly clearance, allowing the single groove structure to fulfill multiple functional requirements.
Solution Approach 2:
The groove transitions from a static fixed-depth structure to a dynamic variable-depth structure that adapts to different operational phases: during assembly, the shallower second portion is utilized for clearance, while during normal operation and burglary resistance, the deeper first portion provides enhanced retention.
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 significantly enhances resistance to burglary attempts by securely retaining the bushing, reducing the risk of damage during assembly, and simplifying production processes while maintaining cost-effectiveness.
Implementation Method 1
a steel elastic ring, of the 'seeger' type, is generally provided
Implementation Method 2
the retaining ring to be housed without radial clearance, ensuring the bushing can freely rotate and is securely associated with the device
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
An antitheft locking device (11), in particular for fixing a wheel to a motor vehicle hub, made in form of a nut or bolt, comprising a body (13) provided with engagement means (21) for a complementary key by means of which it is possible to rotate said device, and an associated bushing (19) freely rotatable around said body (13), in which at least a radial seat (25) is provided for at least a retaining element (23) capable of preventing the axial withdrawal of the bushing (19) from the body (13), said seat being obtained partially in the body (13) of the device and partially in the bushing (19), wherein said seat (25) has a depth varying along the axial direction.