Tape Rule Assembly Optical Encoder Sensor Holder
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Solution Overview
Problem
Conventional tape rules with linear optical encoders require both human-readable and machine-readable indicia on the tape, leading to cluttered surfaces and inaccurate human measurements, and use complex arrangements of rollers and springs to maintain sensor distance, which is inefficient.
Innovation Solution
A tape rule assembly using a sensor holder and radial uncoiling bias to maintain the critical distance between optical sensors and the tape surface, allowing the sensors to read human-readable graduations without machine-readable indicia, and accommodating undulations without rollers or springs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If both human-readable and machine-readable indicia are disposed on the tape, then the optical encoder can sense measurements digitally, but the tape surface becomes cluttered and human reading accuracy deteriorates
Solution Approach 1:
The patent extracts the machine-readable indicia function from the tape surface by using a separate reflective sheet with machine-readable markings that can be applied independently of the human-readable graduations. This allows the optical encoder to read measurements digitally without cluttering the tape surface, resolving the contradiction between automation and human reading accuracy.
2Reliability
If rollers and springs are used to maintain sensor-tape distance, then the critical distance range is maintained, but the device complexity increases
Solution Approach 1:
The patent implements self-service by allowing the tape itself to maintain the critical distance through its natural stiffness and tension characteristics. The tape's inherent mechanical properties automatically keep it at the required distance from the optical encoder sensors without requiring external rollers or springs, thereby maintaining reliability while eliminating complex mechanical arrangements.
3Extent of automation
If machine-readable indicia are added to the tape, then digital encoding is enabled, but the tape surface becomes cluttered with unsightly markings
Solution Approach 1:
The patent segments the measurement indication functions by separating human-readable graduations from machine-readable indicia. The machine-readable markings are placed on a separate reflective sheet that can be applied to the tape背面 or edge, allowing digital encoding capability while keeping the front tape surface clean and visually appealing for human users.
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
Enables accurate digital display of tape length with improved human readability and simplified sensor maintenance, reducing clutter and complexity while maintaining accurate measurements.
Implementation Method 1
around which is wrapped several coils of a retraction spring
Implementation Method 2
uses a sensor holder configured according to the present invention, together with the radial uncoiling bias generated by confining a coil of tape in the housing, to maintain the critical distance from the optical sensors to the surface of the tape
Implementation Method 3
a linear optical encoder senses indicia on a tape to provide an indication of the amount of tape extended from the tape rule housing
Data Source
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AI summary
A tape rule assembly includes a linear optical encoder for sensing human-readable graduations of length disposed on a surface of a tape, without requiring any other machine-readable indicia to be present on the tape. The optical encoder includes two optical sensors disposed in a sensor holder pivotably disposed in the tape rule housing and configured to be displaced relative to one another in the housing along both the "x" axis and the "z" axis, a set of intersecting "x", "y" and "z" axes being defined relative to a tape exit in the tape rule housing.