Breakaway Torque-Limiting Nut for Plastic Faucet Mounting
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Solution Overview
Problem
Existing connection arrangements in sanitary fittings, such as faucets, can suffer damage from excessive tightening torque, particularly when using plastic components, as they do not effectively limit the torque applied during assembly.
Innovation Solution
A method for producing a connection arrangement with a torque limiter that includes a nut with annular stop elements arranged along its outer peripheral surface, which break away at predetermined torque limits, preventing excessive tightening torque from being transmitted to the plastic body, thereby protecting it from damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the nut is screwed tightly to secure the faucet, then the fastening reliability is improved, but the plastic body can be damaged due to excessive tightening torque
Solution Approach 1:
The stop element is designed as a disposable component that breaks away after serving its torque-limiting function. It is intentionally made weaker than the plastic body so that it fractures when the torque exceeds the predetermined limit, thereby protecting the more valuable plastic body from damage. The stop element is replaced with a new one if torque limitation is needed again.
Solution Approach 2:
The stop element acts as an intermediary between the nut and the plastic body. It transmits the tightening torque initially but then fails in a controlled manner to prevent excessive torque from reaching the plastic body. This intermediary component absorbs the harmful effect of over-tightening.
2Object-affected harmful factors
If a torque limiter is implemented using a stop element, then the plastic body is protected from damage, but the device complexity increases
Solution Approach 1:
The stop element is integrated directly into the nut as a single-piece component, combining the torque-limiting function with the fastening component. This eliminates the need for separate torque-limiting devices and reduces overall system complexity despite adding functional capability.
Solution Approach 2:
The stop element is designed to be discarded (broken off) after its protective function is fulfilled. This simple discard mechanism provides effective torque limitation without requiring complex reset or adjustment systems, maintaining ease of use while protecting the plastic body.
3Object-affected harmful factors
If the stop element is designed to break away at predetermined torque, then excessive torque is prevented, but the manufacturing precision requirements increase
Solution Approach 1:
The stop element has a localized weak section with reduced cross-sectional area or altered material properties at a specific location. This local modification creates a predictable failure point that breaks at the predetermined torque while the rest of the nut maintains its full strength and dimensional accuracy.
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 method effectively limits the maximum permissible tightening torque, preventing damage to the plastic components of sanitary fittings by ensuring that the torque applied during assembly does not exceed safe limits, thus ensuring the integrity of the fitting.
Implementation Method 1
breaking away of the first stop element from the outer peripheral surface... when the nut is screwed further with at least the second torque and the second torque is higher than a limit torque defined by the first stop element
Data Source
Figure 1~3
Figure 4~7
AI summary
Method for manufacturing a connection arrangement (1) with a torque limiter, wherein the connection arrangement (1) comprises at least a nut (2) with an internal thread (3), a bolt (4) with an external thread (5), and a body (6) with a stop surface (7) and an opening (8); wherein the bolt (4) is arranged in the opening (8) and extends outwards from the body (6) through the stop surface (7); wherein the nut (2) extends between a first end (9) and a second end (10) along an axial direction (11) and has a hollow cylindrical first section (12) with the internal thread (3) extending from the first end (9), wherein at least one first stop element (17), which is at least partially circumferential along a circumferential direction (15) and extends in a radial direction (16), is arranged on a cylindrical outer circumferential surface (14).