Pneumatic Impulse Wrench Power Control via Exhaust Valve
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Solution Overview
Problem
Pneumatic impulse wrenches lack alternative operation modes for adjusting the exhaust air controlling valve mechanism and are prone to physical damage due to the external location of the valve mechanism, leading to potential over-tightening and costly interruptions.
Innovation Solution
Incorporating an exhaust air flow determining valve mechanism that operates in both automatic and manual modes, with the ability to be manually adjusted for constant exhaust air outlet flow, and integrating it within the wrench housing to protect it from damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If the exhaust air controlling valve mechanism is located externally for easy replacement, then ease of repair is improved, but reliability deteriorates due to exposure to physical damage
Solution Approach 1:
The patent merges the exhaust air controlling valve mechanism with the wrench housing, integrating a previously separate external component into the main housing structure. This eliminates the vulnerability of external placement while maintaining functionality, as the valve mechanism is now protected within the housing yet remains accessible for maintenance.
2Reliability
If the exhaust air controlling valve mechanism is integrated inside the housing for protection, then reliability is improved, but ease of repair deteriorates
Solution Approach 1:
The patent segments the valve mechanism into a modular assembly that can be accessed through the housing structure. The control element is positioned to be reachable from outside the housing, allowing maintenance personnel to adjust or replace the valve mechanism without complete disassembly, thus maintaining ease of repair while achieving protection.
3Productivity
If full motor power is used during running down sequence, then productivity is improved, but manufacturing precision deteriorates due to risk of over-tightening
Solution Approach 1:
The patent implements dynamic control of the exhaust air flow area that automatically adjusts motor power based on the actual torque load. During the running down sequence when torque demand is low, the system automatically reduces exhaust area to limit motor power and speed, preventing over-tightening. When full torque is required, the system restores full power, thus dynamically optimizing both precision and productivity.
Solution Approach 2:
The patent employs feedback control where the exhaust air controlling valve mechanism responds to actual torque load conditions. The system continuously monitors torque demand and adjusts the exhaust air flow area accordingly, creating a closed-loop control that prevents over-tightening by reducing power during low-load running down sequences while maintaining full power capability when needed.
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 precise control of motor power and speed during screw joint tightening, preventing over-tightening and reducing the risk of tool damage, allowing for efficient and reliable operation.
Implementation Method 1
an exhaust air flow determining valve mechanism operated by the actual pressure in the air inlet to the motor
Implementation Method 2
control the exhaust air outlet flow in response to the actual torque load on the motor
Data Source
AI summary
A pneumatic impulse wrench includes a housing with a motor powered impulse unit, a pressure air inlet passage, an exhaust air outlet passage located in the housing and connected to the motor, and a motor power controlling valve mechanism located in the exhaust air outlet passage for automatic control of the exhaust air flow from the motor. A control pressure passage extends between the air inlet passage and the valve mechanism for communicating actual air inlet pressure to the valve mechanism. An operating mode shifting valve is provided in the housing and which is shiftable between an open position in which communication is allowed through the control pressure passage in an automatic valve mechanism operating mode, and a closed position in which communication through the control pressure passage is blocked in a manual valve mechanism operating mode.