Adjustable Spanner Strain Gauge Relocation
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Solution Overview
Problem
Existing adjustable spanners with electronic strain gauges suffer from precision loss due to pressure from screw means and changes in screw size, leading to inaccurate twisting force measurements as the clamping positions and relations between jaws and screw change.
Innovation Solution
An adjustable spanner design with a moveable jaw having a positioning portion and sliding groove, where the clamping surfaces are parallel to the handle's central axis, maintaining consistent strain gauge measurements by adjusting the jaw's position relative to the screw, and incorporating strain gauges on the handle's neck and an output display device connected to a power source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If strain sensors are adhered on the clamping surfaces of the retaining jaw and moveable jaw, then the electronic strain gauge function is achieved, but the precision of the strain sensors deteriorates due to pressure from the screw means
Solution Approach 1:
The patent extracts the strain measurement function from the clamping surfaces and relocates it to the handle body. The strain gauges are now adhered on the handle body instead of on the jaws, separating the measurement location from the high-pressure clamping zone. This extraction resolves the contradiction by maintaining the electronic strain gauge function while eliminating the pressure-induced precision deterioration.
2Adaptability or versatility
If the size of the screw means to be measured is changed, then the clamping positions of the adjustable spanner to the screw means will change, but the precision of the measuring strain will not be retained
Solution Approach 1:
By extracting the strain measurement location from the jaws to the handle body, the measurement point is removed from the variable clamping positions. The handle body remains at a fixed distance from the screw means regardless of screw size, allowing the spanner to adapt to different screw sizes while maintaining consistent measurement precision.
Solution Approach 2:
The patent creates an equipotential measurement condition by positioning the strain gauges on the handle body where the mechanical stress distribution remains consistent across different measuring scenarios. This ensures that the strain measurement remains reliable regardless of variations in screw size or clamping position.
3Adaptability or versatility
If the clamping positions of the adjustable spanner change with different screw sizes, then the spanner can accommodate various screw dimensions, but the respect relations of the edges and sides of the moveable jaw, retaining jaw and the screw means are changed, leading to inaccurate twisting force measurement
Solution Approach 1:
The patent extracts the measurement function from the variable clamping positions on the jaws and relocates it to the fixed handle body position. This allows the clamping positions to change with different screw sizes while the measurement point remains constant, eliminating the relationship changes that cause measurement inaccuracies.
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 design ensures precise strain measurements with minimal error (about 0.107% to 3%), maintaining accuracy across different screw sizes by maintaining consistent distances from the screw's central point to the strain gauge, thus providing a precise and reliable measuring effect.
Implementation Method 1
two sides of the neck having strain gauges
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
An adjustable spanner with electronic strain gauge function which comprises a head (12); an retaining jaw (121) extending from the head (12); and sliding groove (122) being transversally formed at one upper side of the head (12); a handle (14) connected to a lower side of the head (12); at least one strain gauge (18); a hollow connecting tube (16) having one end connected to the handle (14); the hollow connecting tube (16) being installed with an output display device (20); a clamping surface (1233) of the moveable jaw (123) and a clamping surface (1211) of the retaining jaw (121) being formed as a working area for clamping a screw device (L1,L2,L3); and a positioning portion (13) being installed on the moveable jaw (123) and at a non-working area below the work area; the position portion (13) facing toward a clamping opening between the clamping surfaces (1233,1211) of the moveable jaw (123) and retaining jaw (121); and the positioning portion (13) being capable of resisting against the screw device (L1,L2,L3).