Compact Torque Wrench with Radial Indicator and Planetary Gear
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Solution Overview
Problem
Existing bolt or nut tightening devices require large and expensive power tightening machines with reduction mechanisms, making them cumbersome and difficult to use, and the torque indicators are not easily readable during operation.
Innovation Solution
A bolt or nut tightening device with a planetary gear mechanism that includes a strain gauge for torque measurement, a compact circuit board, and a rotatable indicator case, allowing for use with small power machines or manual wrenches, ensuring maneuverability and easy torque reading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a large power tightening machine with reduction mechanism is used, then great tightening torque can be achieved, but the device becomes cumbersome and difficult to maneuver
Solution Approach 1:
The device is divided into two functional parts: a compact measuring unit that can be easily maneuvered and a separate power tightening machine that provides the necessary torque. The measuring unit includes only the essential components (strain gauge, indicator, battery) while the power machine handles the torque generation, allowing the measuring unit to remain lightweight and easy to handle.
Solution Approach 2:
The measuring function is extracted from the power tightening machine and placed in a separate, compact unit. This allows the measuring unit to be small and maneuverable while the power machine (which can be left stationary or positioned separately) provides the great tightening torque through its reduction mechanism.
2Volume of moving object
If the indicator digits are arranged axially along the tubular casing, then the structure is compact, but the values are difficult to read during operation
Solution Approach 1:
The indicator digits are arranged radially (circumferentially) around the tubular casing instead of axially along it. This radial arrangement allows the digits to be positioned perpendicular to the axis of the casing, making them easily readable from the side while maintaining a compact axial length. The indicator displays torque values in a direction that is convenient for the operator to view during operation.
3Reliability
If the case is made large to accommodate components, then protection and rigidity are improved, but the outside diameter and length increase
Solution Approach 1:
The circuit board, indicator, and battery are nested within the tubular casing in a space-efficient arrangement. The components are positioned concentrically and radially to maximize space utilization, allowing adequate protection and rigidity while keeping the overall length and outside diameter of the unit compact.
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 device is lightweight, compact, and easy to use, providing accurate torque readings while preventing damage from impacts and improving maneuverability, as the compact design and planetary gear mechanism enhance usability and reliability.
Implementation Method 1
a strain gauge or like strain sensor provided on the outer shaft
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A bolt or nut tightening device comprises the combination of input means (9) and a tightening assisting unit (1) having an outer shaft (4) and an inner shaft (3) coupled to a planetary gear mechanism (2) coaxially therewith and rotatable in directions opposite to each other, the outer shaft (4) having a reaction receiver (6) projecting therefrom sideways, the inner shaft (3) being provided with an engaging portion (6) engageable with a bolt or nut to be tightened. The outer shaft (4) is provided with a tightening torque measuring unit (7), which comprises a strain gauge (71) or like strain sensor (71a) provided on the outer shaft (4), a circuit board (72) for converting the amount of strain of the outer shaft (4) as detected by the strain sensor (71a) to an amount of tightening torque, an indicator (73) for indicating the amount of tightening torque, a battery (74), and a case (75) for accommodating the circuit board (72), the indicator (73) and the battery (74). The case (75) is attached to the outer shaft (4), projects toward the same direction as the reaction receiver (5), is so sized as to be hidden by a contour of the reaction receiver (5) and is so positioned as to be hidden behind the reaction receiver (5) when seen from the forward end side of the engaging portion (6).