Cylinder-Piston Position Detection Using Adhesive Tape Codification
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Solution Overview
Problem
Current methods for continuously detecting the reciprocal position between a cylinder and piston in hydraulic or pneumatic cylinder-piston units are limited by the complexity and cost of manufacturing reference codifications, and require precise, reliable, and practical solutions.
Innovation Solution
A cylinder-piston unit with a reference codification featuring a plurality of adjacent sectors, each with multiple optical contrast zones of varying extensions, and detecting means that utilize light radiation emitters and sensors to differentiate reflected signals, allowing for continuous position detection with a control and data elaboration unit to correlate the signals to the piston's position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional laser marking technology is used to create reference codification on the piston rod, then continuous position detection is achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent replaces expensive laser-marked reference codification with a cheap adhesive tape bearing the code. This disposable-like approach (where the tape can be replaced if needed) dramatically reduces manufacturing cost while maintaining detection functionality. The tape is a low-cost alternative to permanent laser marking, achieving the same measurement purpose without the high manufacturing overhead.
Solution Approach 2:
Instead of creating unique laser-marked codes directly on the piston rod, the patent uses adhesive tapes that carry copied reference codification patterns. These tapes can be manufactured separately and applied to the rod, separating the code creation process from the rod manufacturing process, thereby reducing overall manufacturing complexity and cost.
2Ease of manufacture
If simple adhesive tapes are used for reference codification, then manufacturing cost is reduced, but detection reliability may be compromised
Solution Approach 1:
The patent enhances the reliability of the adhesive tape solution by changing parameters such as using opaque materials with high contrast, optimizing the adhesive properties for industrial conditions, and selecting materials resistant to temperature and chemical variations. These parameter optimizations ensure the tape maintains its coding integrity under various operating conditions, achieving detection reliability comparable to laser marking.
Solution Approach 2:
The patent applies specific quality enhancements to critical areas of the tape, such as using higher-grade adhesive in regions subject to vibration or temperature changes, and ensuring the code pattern areas have optimal contrast and durability. This localized quality approach ensures reliability where needed most while keeping overall manufacturing costs low.
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, precise, and reliable method for continuous detection of the reciprocal position, simplifying implementation and maintaining accuracy through the use of multiple optical contrast zones and advanced signal processing techniques.
Implementation Method 1
a respective sensor's means, in charge to detect such light radiations reflected from the rod's surface
Implementation Method 2
The light radiations produced from the emitter means are, indeed, reflected almost totally from the unmarked surface of the piston's rod, while they are indeed in majority absorbed, when they are incident on a marked surface of the rod
Data Source
Figure 1a~1c
Figure 1d
Figure 2a~2b
AI summary
A cylinder-piston unit including: at least one cylinder including a tubular body (2); at least one piston (5) liable with a respective rod (5a), said piston (5) and said rod (5a) being translatable longitudinally in said tubular body (2) of said cylinder, at least one reference codification (C) extending for at least a section (dC) on the surface of said rod (5a), along the longitudinal axis of the same; at least detecting means (7), movable anchorable to said tubular body (2), faced, in use, towards said rod (5a) and suitable to detect said at least one reference codification (C) and to emit at the output at least a corresponding output electrical signal (s7), at least a reference zone (7c) of amplitude (d7c) delimited from said detecting means (7), said at least one reference codification (C) being detectable in correspondence to said at least one detection zone (7c); said at least one reference codification (C) including at least one plurality of adjacent sectors (...,Si-1, Si, Si+1,...) extending along said longitudinal axis of said rod (5a), each of them for a section (dSi) of equal length; each sector (Si) includes a plurality of optical contrast zones (si1, si2, si3), each of them extending along said longitudinal axis of said rod (5a) for a respective section of extension (dsi1, dsi2, dsi3) such as the sum of the extensions of said sections of extensions (dsi1+dsi2...), in each sector (Si) is lower or equal to said amplitude (d7c) of said detecting zone (7c); said optical contrast zones (si1, si2, si3) being arranged in each sector (Si) according to the same sequence; and wherein in each sector (Si) at least one optical contrast zone (si1, si2, si3) shows said at least one respective section of extension (ds1, ds2, ds3) of different length compared to the length of the same section of extension in the other sectors (Si-2, Si-1, Si+1, Si+2,...), therefore each sector (Si) remains univocally definable from the length of said at least one section of extension (dsi1, dsi2, dsi3) of said optical contrast zones (si1, si2, si3) in it included.