Theft-Protected Screw Part With Projection-Based Insert Connection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Thief-protected screw parts used to secure vehicle wheels are heavier than standard screws due to the need for a larger axial length to accommodate a bore hole, which weakens the shaft and screw portion, compromising strength and increasing weight.
Innovation Solution
A theft-protected screw part design featuring a projection on the main part instead of a bore hole, allowing the insert to be permanently connected and aligned in various angular positions, reducing the overall length and weight while maintaining security through encoding arrangements, and using a deformation process to ensure a strong connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an accommodating bore hole is provided in the main part to house the insert, then the insert can be permanently connected and aligned, but the axial length must be increased to keep the bore hole outside the threaded portion, resulting in increased weight and reduced strength
Solution Approach 1:
Instead of providing an accommodating bore hole in the main part to house the insert (as in prior art), the invention inverts the approach by providing a projection on the main part that fits into a hole in the insert. This reversal allows the threaded portion to be shortened and positioned closer to the head, reducing overall axial length and weight while maintaining connection strength through the deformed projection that absorbs torque.
2Strength
If the axial length is increased to accommodate the bore hole outside the threaded portion, then the threaded portion is not weakened, but the overall weight of the screw part increases
Solution Approach 1:
The invention reverses the conventional arrangement by placing the fastening feature (projection) on the main part rather than in the insert. This allows the threaded portion to be shorter and stronger, as it does not need to extend axially to accommodate a bore hole, thereby reducing weight while maintaining or improving strength.
Solution Approach 2:
The invention changes the axial length parameter of the threaded portion by repositioning it closer to the head through the inverted projection-hole arrangement. This parameter change reduces the overall axial length of the screw part, decreasing weight while the deformation process ensures the threaded portion retains sufficient strength.
3Strength
If the insert is permanently connected to the main part through deformation, then torque is absorbed and connection strength is enhanced, but the manufacturing process becomes more complex
Solution Approach 1:
The projection is designed to be deformable and serves its own fastening function through the deformation process. The material of the projection itself is used to create the locking connection by deforming it to engage with the insert, eliminating the need for separate fastening elements or complex assembly operations. This self-service approach enhances connection strength while keeping the manufacturing process relatively simple.
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 design achieves a weight comparable to standard screws, enhancing vehicle driving behavior by reducing mass without compromising strength or security, as the projection-based connection absorbs torque and prevents easy removal or destruction.
Implementation Method 1
The projection is now deformed in this state. Alternatively, the projection is permanently connected firmly with the projection in a suitable manner, this may be done, for example, by welding.
Data Source
AI summary
The theft-protected screw part in the form of a nut or a screw has a free end region and a ring-shaped depression formed at the end region for the engagement of a wrench for rotation the screw part. Viewed from radially outside to radially inside, the depression is delimited by an outer edge, a bottom and an inner edge. The outer edge forms outer abutment surfaces and the inner edge forms inner abutment surfaces for the wrench. The screw part is composed of a main part and an insert. The main part has a protrusion, which is located within the inner edge. The insert is designed in a ring shape, has a hole for accommodating the protrusion and forms the inner abutment surfaces.