Torque Adapter Segmented Zones Stall Torque
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Solution Overview
Problem
Existing methods for measuring the stall torque of rotary power tools are not accurate due to internal resistive forces like frictional resistance, which affect the rotational output and make it difficult to determine the maximum torque reliably.
Innovation Solution
A torque adapter with a housing and a mandrel that includes an arcuate recess and protrusion, along with a resistance subassembly using a biasing member, allows for controlled rotational resistance zones to accurately measure the stall torque by overcoming initial frictional resistance before reaching the stall point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a traditional torque measuring device is used, then the structure is simple, but the measurement precision of stall torque is insufficient due to internal resistive forces
Solution Approach 1:
The torque adapter is divided into distinct functional zones: a first rotational zone with nominal resistance for overcoming internal friction, and a second rotational zone with increasing resistance for accurate stall torque measurement. This segmentation allows the device to separate the effects of internal resistance from the actual stall torque being measured.
Solution Approach 2:
The resistance subassembly acts as an intermediary element between the rotary power source and the measurement system. It introduces controlled resistance that compensates for internal resistive forces, allowing the torque transducer to measure the true stall torque without the confounding effects of internal friction.
2Reliability
If internal resistive forces are present, then the device structure remains simple, but the reliability of torque measurement deteriorates
Solution Approach 1:
The first rotational zone provides preliminary resistance that counteracts internal frictional forces before the measurement phase begins. This preliminary anti-action ensures that when the second zone measures torque, the internal resistive forces have already been overcome and compensated for.
Solution Approach 2:
The resistance subassembly provides dynamically varying resistance across the two rotational zones. In the first zone, resistance remains nominal to allow acceleration and overcome static friction. In the second zone, resistance increases to accurately reflect the stall torque condition, making the measurement process dynamic rather than static.
3Measurement precision
If a single rotational zone is used, then the device complexity is low, but the measurement precision deteriorates due to inability to distinguish frictional resistance from stall torque
Solution Approach 1:
The measurement process is segmented into two distinct rotational zones with different resistance characteristics. The first zone handles acceleration and friction overcoming, while the second zone performs the actual stall torque measurement. This segmentation allows clear distinction between frictional effects and true stall torque.
Solution Approach 2:
Different regions of the rotational path are given different quality characteristics: the first rotational zone has nominal resistance suitable for overcoming friction, while the second rotational zone has increasing resistance suitable for precise stall torque measurement. Each zone is optimized for its specific function.
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 enables a more precise measurement of stall torque by distinguishing between nominal and increasing rotational resistance zones, allowing the rotary power tool to overcome internal frictional forces before measuring the maximum torque supplied, thus providing a more accurate reading.
Implementation Method 1
The resistance subassembly includes a biasing member and is received into the arcuate recess... when the mandrel is rotated relative to the housing, the mandrel encounters nominal rotational resistance while the arcuate protrusion passes through the first rotational zone, and the mandrel encounters increasing rotational resistance while the arcuate protrusion passes through the second rotational zone
Data Source
Figure 1
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Figure 4
AI summary
A torque adapter for measuring a stall torque supplied by a rotary power source includes a housing, a mandrel rotatable relative to the housing, and a resistance subassembly. The housing includes an arcuate recess defined at least partially by a recess front wall and a recess back wall. The arcuate recess includes a first rotational zone bounded on one side by the recess front wall, and a second rotational zone bounded on an opposite side by the recess back wall. The mandrel includes a flange portion having an arcuate protrusion received in the arcuate recess. The resistance subassembly includes a biasing member and is received into the arcuate recess. When the mandrel is rotated relative to the housing, the mandrel encounters nominal rotational resistance while the arcuate protrusion passes through the first rotational zone, and the mandrel encounters increasing rotational resistance while the arcuate protrusion passes through the second rotational zone.