Overmolded Joystick Control Arm for Precise Sensing Under Vibration
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Solution Overview
Problem
Existing joysticks face challenges in manufacturing precision due to metal control arms, leading to inaccurate measurements and increased costs, and struggle with sealing issues in harsh environments, causing incorrect signals and reduced durability.
Innovation Solution
A joystick with a plastic control arm made through injection molding, featuring an overmolded magnetic member and a sealing plate for water and dust protection, ensuring precise positioning and enhanced durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If metal control arms are used with magnets attached, then the joystick can detect position, but manufacturing precision deteriorates and costs increase
Solution Approach 1:
The control arm is made from a composite material combining plastic and magnetic substances through overmolding. This integrates the magnetic function directly into the structural component, eliminating separate magnet attachment operations and achieving precise, consistent magnetic field positioning without additional manufacturing complexity
Solution Approach 2:
The magnetic member is merged with the control arm through overmolding, combining the structural function of the control arm with the sensing function of the magnet. This integration ensures the magnetic field source is precisely positioned relative to the sensor, resolving the positioning accuracy issue
2Adaptability or versatility
If multiple switches and rollers are coupled to a printed circuit board, then control functions are expanded, but sealing problems worsen due to open upper surface
Solution Approach 1:
A flexible boot made of elastomeric material is used to seal the upper surface of the housing where multiple control elements are mounted. The flexible nature of this boot allows it to conform to the complex geometry of switches and rollers while providing effective sealing against dust and moisture
Solution Approach 2:
The boot is made from elastomeric composite material that provides both flexibility for sealing around multiple control elements and durability for environmental protection. This material choice enables the housing to maintain sealing integrity while supporting expanded control functions
3Strength
If control arms are made of metal, then structural strength is achieved, but vibration resistance deteriorates causing incorrect signals
Solution Approach 1:
The control arm uses a composite of plastic and magnetic substances that provides sufficient structural strength while being inherently more resistant to vibration-induced signal errors. The plastic matrix dampens vibrations better than metal, while the embedded magnetic particles maintain the magnetic field for sensing
Solution Approach 2:
The magnetic field-based sensing system replaces mechanical contact-based sensing that would be more susceptible to vibration. The non-contact magnetic field detection through the plastic control arm provides stable position feedback even under vibrational conditions
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 provides a cost-effective, durable, and precise control mechanism that resists vibrations and maintains accuracy, while reducing manufacturing complexity and environmental susceptibility.
Implementation Method 1
an overmolded magnetic member (20) suitable to interact with the sensor (47)
Data Source
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AI summary
The present invention relates a joystick (100) for controlling a machine in multi-axes, comprising a control portion (30) having a body (41) in which at least one circuit board (44) having at least one sensor (47) is provided; a top portion (10) having a flexible boot (60) forming at least partly an outer periphery of the top portion (10) provided on the control portion (30); a control arm (80) mounted on a pivotal member (40) for pivotal movement relative to the body (41); wherein said control arm (80) is made of plastic in an injection-molding operation and has an overmolded magnetic member (20) suitable to interact with the sensor (47), said magnetic member (20) provided in the proximity of the circuit board (47) wherein said control arm (80) has a connection portion such that said flexible boot (60) is attached to the control arm (80) from said connection portion. Thereby usage of the overmolded control arm (80) which made of plastic provides sensitivity, production quality and additionally, thriving resistance to vibration.