Float Arm Fixing Mechanism for Liquid Level Sensors
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Solution Overview
Problem
Existing liquid level detecting devices face challenges in securely fixing the float arm to the holder without increasing costs or complexity, as the float arm can come off due to applied loads during assembly, leading to structural complications.
Innovation Solution
The device incorporates an arm fixing portion with a lock hole, holding groove, and retaining claw, featuring a holding projection that increases in length away from the lock hole and an inclined holding surface to securely lock the float arm, allowing easy attachment and preventing dislodgment under cross-directional loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lock portion is reinforced to prevent the float arm from coming off, then the reliability of the float arm fixation is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The arm fixing portion is divided into multiple functional elements: a lock hole for initial positioning, a holding groove for securing the float arm, and a retaining portion with a claw for final locking. This segmentation allows each element to perform its specific function efficiently without requiring overall structural reinforcement, thereby maintaining simplicity while improving reliability.
Solution Approach 2:
The holding groove acts as an intermediary structure between the lock hole and the retaining portion. It receives and positions the float arm in a predetermined location, facilitating easy attachment while the retaining portion's claw provides the secure locking mechanism. This intermediary structure eliminates the need for a complex reinforced lock portion.
2Reliability
If the lock portion is reinforced to prevent the float arm from coming off, then the reliability of the float arm fixation is improved, but the manufacturing cost increases
Solution Approach 1:
By segmenting the arm fixing portion into distinct functional elements (lock hole, holding groove, retaining portion), each can be manufactured using simple, cost-effective processes. The structure avoids the need for expensive reinforced materials or complex machining operations, maintaining low manufacturing costs while achieving high reliability through the coordinated action of multiple simple components.
Solution Approach 2:
The holding groove and retaining portion are designed to automatically secure the float arm through their geometric configuration. The claw of the retaining portion locks onto the float arm when it is inserted into the holding groove, providing self-securing functionality that eliminates the need for additional fasteners or complex assembly procedures, thereby reducing manufacturing costs.
3Ease of manufacture
If a simple lock portion structure is used to reduce cost and complexity, then the ease of manufacture is improved, but the float arm may come off under load
Solution Approach 1:
The retaining portion is designed with a claw that provides localized locking action at the critical point where the float arm meets the holder. This localized quality enhancement ensures reliable retention under load without requiring overall structural reinforcement, maintaining manufacturing simplicity while achieving the necessary reliability at the specific location where it is most needed.
Solution Approach 2:
The arm fixing portion is designed to dynamically respond to loads. When the float arm is inserted, the holding groove positions it and the retaining portion's claw engages to lock it in place. Under operational loads, this dynamic engagement ensures the float arm remains securely fixed without requiring a statically reinforced structure, maintaining ease of manufacture while ensuring reliability.
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
This configuration enables reliable and cost-effective fixation of the float arm to the holder, preventing dislodgment even under cross-directional loads, facilitating easy assembly without structural complexity or cost increases.
Implementation Method 1
a Hall element which is provided in the sensor housing and detects a displacement of the magnet of the holder
Data Source
AI summary
A liquid level detecting device includes a sensor housing, a holder, an arm fixing portion provided in the holder, a float arm, a float, a magnet provided in the holder, and a Hall element. The arm fixing portion includes a lock hole configured to receive a lock end portion of the float arm, a holding portion having a holding groove, and a retaining portion having a claw. The holding portion has a holding piece that extends parallel with a front surface of the holder and thereby forms the holding groove. The holding piece has a holding projection that projects toward the front surface of the holder so that a projection length of the holding projection increases gradually as the holding piece goes away from the lock hole.