SMA Haptic Assembly Sheet Material Guide Tortuous Wire Path
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge is to reduce the size of shape memory alloy (SMA) haptic assemblies used in handheld devices without increasing manufacturing and assembly costs, while maintaining functionality, as space within these devices is limited.
Innovation Solution
The solution involves using SMA haptic assemblies formed from sheet material, where one or both parts are made from sheet material, with contact and connection portions integrally formed to guide the SMA wire along a tortuous path, reducing the assembly's size and complexity, and incorporating features like support portions, connection elements, and insulating materials to prevent short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional manufacturing methods (machining or injection moulding) are used to produce haptic assembly parts, then the parts can be manufactured with sufficient strength and precision, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent changes the manufacturing method from traditional machining or injection moulding to stamping or chemical etching of sheet material. This parameter change in the manufacturing process enables simpler, more cost-effective production while still achieving the required precision for contact portions and connection portions through appropriate sheet material selection and processing technique optimization.
2Strength
If thicker parts are used to provide sufficient structural support and force transmission, then the assembly strength is improved, but the overall size of the assembly increases
Solution Approach 1:
The patent employs thin sheet material (e.g., 0.15mm to 0.5mm thick) to form the first and second parts, replacing traditional thicker molded or machined components. The sheet material is shaped to provide necessary structural support and force transmission through its geometry and integration with the SMA wire, achieving adequate strength while significantly reducing the overall assembly size for handheld device applications.
3Volume of moving object
If the contact portions are positioned to guide the SMA wire along a straight path, then the assembly size is reduced, but the SMA wire cannot effectively drive the parts in opposite directions
Solution Approach 1:
The patent incorporates tortuous (curved) paths for the SMA wire within the contact portions of the first and second parts. This curvature allows the wire to effectively transmit contraction forces to drive the parts in opposite directions along the movement axis while maintaining a compact assembly size. The tortuous path ensures proper force transmission geometry without requiring excessive space.
4Stability of the object's composition
If both ends of the SMA wire are connected to different parts, then the force distribution is balanced, but the manufacturing and assembly complexity increases
Solution Approach 1:
The patent integrates both ends of the SMA wire into the same sheet material part (either the first part or the second part), rather than connecting each end to separate parts. This merging approach maintains balanced force distribution through the sheet material structure while significantly simplifying manufacturing and assembly processes, as fewer separate components and connection steps are required.
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 approach minimizes the size of the SMA haptic assembly, simplifies manufacturing, and prevents electrical shorts, ensuring effective haptic feedback without increasing costs or compromising device functionality.
Implementation Method 1
SMA actuators are known for use in handheld electronic devices... they can be used to provide haptic functionality for tactile feedback... Such actuators typically function by using the contraction of an SMA wire to cause relative motion of two components
Implementation Method 2
the at least one contact portion of the first part and the at least one contact portion of the second part being relatively positioned so as to guide the length of SMA wire along a tortuous path
Data Source
AI summary
An SMA haptic assembly comprises relatively movable first and second parts and a length of SMA wire, the ends of which are connected to the first part or second part, wherein the first and second parts comprise at least one contact portion making contact with the length of SMA wire on opposite sides of the length of SMA wire and relatively positioned so as to guide the length of SMA wire along a tortuous path such that the first and second parts are driven in opposite directions along a movement axis on contraction of the length of SMA wire. The at least one contact portion of one or both of the first and second parts is formed from sheet material that is shaped to guide the path of the SMA wire in contact therewith, thereby reducing the overall thickness and simplifying manufacture.