Driving Tool Timer Assembly Inertial Mode Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing driving tools, such as pneumatic nailers, face issues with accidental operations due to the instability of timer assemblies under heat conditions, particularly those using silicone oil in rotary dampers, which affect the speed and reliability of mode switching between single and continuous driving modes.
Innovation Solution
A driving tool incorporating a timer assembly with a flywheel and contact restrictor that utilizes inertial force to set a predetermined period for mode switching, ensuring stable operation and preventing accidental driving by locking the contact arm when the trigger is activated, thus avoiding heat-related instability issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a timer assembly using silicone oil in a rotary damper is used to control mode switching, then the timer can prevent accidental operations, but the operating speed becomes unstable under heat conditions
Solution Approach 1:
The patent changes the physical parameter of the timing mechanism from a silicone oil-based rotary damper to a spring-based system. The spring constant and moment of inertia are adjusted to maintain a predetermined timing period while achieving temperature-stable operation. This parameter change eliminates the heat sensitivity of the original system.
Solution Approach 2:
The patent replaces the viscous damping mechanism (silicone oil rotary damper) with a mechanical spring-based timing mechanism. The spring 48 and flywheel 43 create a predictable oscillation period based on mechanical properties rather than fluid viscosity, which is temperature-sensitive. This substitution maintains timing functionality while improving thermal stability.
2Ease of operation
If compressed air is used to move the stem of the activating valve, then the valve can be controlled, but it takes time to turn on or off the valve, degrading quick driving performance
Solution Approach 1:
The patent extracts the timing function from the valve control system. The timer assembly 20 operates independently to control the activating valve 11, separating the timing mechanism from the air pressure system. This allows the valve to respond quickly to timing signals without being slowed by compressed air delivery to the valve stem.
Solution Approach 2:
The patent introduces the timer assembly 20 as an intermediary between the trigger mechanism and the activating valve. The timer processes the trigger signal and controls valve activation timing, mediating between user input and valve action to achieve both quick response and accurate timing control.
3Adaptability or versatility
If a microswitch and timer are used for mode switching, then single and continuous driving modes can be controlled, but the system requires power supply that may stop or disconnect
Solution Approach 1:
The timer assembly operates as a self-contained mechanical timing system that does not require external power supply. The spring 48 and flywheel 43 create a self-sustaining oscillation that provides timing functionality without batteries or electrical power, making the mode switching capability independent of power supply status.
Solution Approach 2:
The patent replaces the electronically-controlled microswitch system with a purely mechanical timer assembly. The mechanical components (spring, flywheel, gears) provide mode switching control without requiring electrical power, eliminating the reliability issue of power supply dependency while maintaining adaptability for both single and continuous driving modes.
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 solution provides a stable and reliable mode switching mechanism that prevents accidental driving operations, maintaining consistent performance even under varying temperature conditions, and ensures continuous operation without power supply disruptions.
Implementation Method 1
a contact restrictor movable between an unlock position at which the contact restrictor allows the contact arm to move to the arm-on-position and a lock position at which the contact restrictor restricts the contact arm from moving to the arm-on-position, the contact restrictor being configured to take a predetermined period to move from the unlock position to the lock position in response to the trigger moving to the trigger-on-position, the predetermined period being defined by an inertial force generated by rotation of the flywheel
Data Source
AI summary
A driving tool including a timer assembly less susceptible to heat operates at a stable operating speed. The driving tool includes a trigger, a contact arm, and a timer assembly that operates in response to the trigger moving to a trigger-on-position with the contact arm remaining at an arm-off-position. The timer assembly includes a flywheel rotatable in response to the trigger moving to the trigger-on-position, and a contact restrictor movable between an unlock position at which the contact restrictor allows the contact arm to move to an arm-on-position and a lock position at which the contact restrictor restricts the contact arm from moving to the arm-on-position. The contact restrictor takes a predetermined period to move from the unlock position to the lock position in response to the trigger moving to the trigger-on-position. The predetermined period is defined by an inertial force generated by rotation of the flywheel.