Linear Actuator Position Sensing With a Sliding Potentiometer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing linear dual actuators for furniture, particularly in the affordable range, lack the ability to accurately detect intermediate positions between end-positions, relying on expensive and complex end-stop switches for position determination.
Innovation Solution
The use of a sliding potentiometer, mounted parallel to the spindle and mechanically connected to the adjustment element, allows for the detection of end-positions and intermediate positions as an absolute measurement, enabling simpler and cost-effective control of the actuator sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If end-stop switches are used to determine end-positions, then the actuator can detect end-positions, but it cannot detect intermediate positions and the system becomes more complex and expensive
Solution Approach 1:
The patent replaces the mechanical end-stop switch system with an electrical potentiometer-based measurement system. The potentiometer provides continuous analog position feedback through voltage division, eliminating the need for discrete mechanical switches and enabling intermediate position detection without increasing system complexity
Solution Approach 2:
The patent introduces a potentiometer as an intermediary measurement element between the spindle nut and the control system. This potentiometer mechanically couples to the spindle nut through the adjustment element, providing continuous position information to the control unit without requiring direct mechanical switch activation
2Adaptability or versatility
If end-stop switches are used for position determination, then the actuator structure is simple, but the ability to detect intermediate positions is lost
Solution Approach 1:
The potentiometer serves multiple functions simultaneously: it detects end-positions, detects intermediate positions, provides absolute position information, and enables continuous feedback control. This single component replaces what would otherwise require multiple specialized sensors or switches, maintaining manufacturing simplicity while dramatically increasing functional versatility
3Measurement precision
If sliding potentiometer is used for position detection, then intermediate positions can be detected accurately, but the cost may increase
Solution Approach 1:
The patent employs relatively inexpensive sliding potentiometers that provide sufficient measurement accuracy for the application requirements. These cost-effective potentiometers are replaced if needed, and their low individual cost allows for accurate intermediate position detection without significantly increasing overall system price
Solution Approach 2:
The patent changes the measurement parameter from discrete binary switch states to continuous analog voltage signals from the potentiometer. This parameter change enables accurate intermediate position detection while using relatively simple and inexpensive potentiometer components rather than complex expensive sensors
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 solution provides accurate and reliable detection of end-positions and intermediate positions, enhancing control precision and reducing costs, while allowing for individual adjustment and absolute positioning without the need for end-stop switches.
Implementation Method 1
a sliding potentiometer (17) is mounted in the housing parallel to the spindle (14), whose adjustment element (12) is mechanically connected to the spindle nut (12)
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A linear dual actuator for a sitting and/or lying furniture comprising an adjustable section, which is adjusted by means of a pivot shaft (4) furnished with an arm (5) . The actuator is of the type comprising a housing (8) with an aperture for the pivot shaft (4), and where the arm reaches into the housing after the actuator is mounted on the pivot shaft. The actuator comprises a spindle nut constructed as a power transmitting sliding element (12) mounted on the spindle (14) driven by an electromotor over a transmission. The spindle nut is secured against rotation in the housing, which can be brought into engagement with the arm for pivoting the pivot shaft. For determining the position of the section the actuator comprises a sliding potentiometer (17) arranged parallel to the spindle and where the spindle nut is directly mechanically connected to the sliding potentiometer. By means of the signal from the sliding potentiometer a position determination of the section is achieved.