Cordless Nailer Driver Return Mechanism for Concrete Fasteners
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Solution Overview
Problem
Cordless electric nailers are not suitable for steel framing or concrete construction applications due to the failure of driver return springs when subjected to the energy required to drive concrete fasteners, necessitating a more robust driver return mechanism for improved reliability.
Innovation Solution
A cordless electric nailer with a power take-off assembly and driver return assembly, featuring a battery-powered electric motor-driven flywheel and a solenoid-driven plunger with a pivotable return pawl, which engages a return rack to efficiently return the nail driver to its home position, providing a robust and reliable mechanism for driving concrete fasteners.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spring mechanisms are used to return the nail driver, then the structure remains simple, but the reliability deteriorates when subjected to high energy concrete fastener driving
Solution Approach 1:
The patent replaces the traditional spring-based mechanical return system with an electric motor-driven mechanism. The motor (202) activates a pawl (204) that engages with a rack (206) on the driver (64) to mechanically return it to the home position. This substitution of mechanical spring energy storage with an electric motor provides reliable, controlled return motion even after high-energy concrete fastener driving operations.
2Reliability
If a robust driver return mechanism is implemented, then the reliability improves for concrete fastener applications, but the device complexity increases
Solution Approach 1:
The return mechanism is segmented into distinct functional components: the electric motor (202) provides power, the pawl (204) acts as a one-way engagement component, and the rack (206) translates rotational motion to linear driver return. This segmentation allows each component to be optimized for its specific function while maintaining overall system reliability for demanding concrete fastening applications.
Solution Approach 2:
The pawl-rack mechanism serves as an intermediary between the electric motor and the driver. The motor does not directly move the driver; instead, it activates the pawl which engages the rack to provide controlled, incremental return motion. This intermediary mechanism ensures reliable driver return while isolating the motor from direct mechanical loads during the return stroke.
3Productivity
If the nail driver is returned to home position after each shot, then productivity improves, but the mechanism complexity increases
Solution Approach 1:
The electric motor-driven return mechanism ensures continuous, reliable operation by automatically returning the driver to the home position after each firing cycle. This eliminates downtime associated with manual resetting or spring failure, maintaining continuous productive action. The motor activates only when needed for driver return, keeping the system simple during non-operational states while providing robust functionality during operation.
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 enhances the reliability and efficiency of cordless electric nailers by enabling them to handle concrete fasteners effectively, reducing the risk of driver return spring failure and improving operational consistency in demanding construction applications.
Implementation Method 1
The driver return assembly includes a solenoid driving a plunger in a reciprocating motion
Implementation Method 2
a battery-powered electric motor driven flywheel
Data Source
Figure 1
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AI summary
A driver return assembly (18) can be positioned to return a concrete nail driver (64) of a cordless electric powered nailer (10) to the home position. A return rack (206) can be fixedly coupled to and positioned along a longitudinal length of the concrete nail driver. The driver return assembly can include a solenoid (230) driving a plunger (232) in a reciprocating motion in a homeward direction and a driven direction. A return pawl (204) can be coupled to the plunger and pivotable into a pawl raised position relative to the plunger in which the pawl is engageable with the return rack during movement of the plunger in the homeward direction, and pivotable into a pawl lowered position relative to the plunger in which the pawl is not engageable with the return rack during movement of the plunger in the driven direction.