Hammer Drill Torque Clutch for Screw Tightening
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Solution Overview
Problem
Conventional hammer drills cannot effectively tighten screws due to their inherent striking motion, requiring additional tools like electric drivers, and lack a tightening-torque adjusting clutch to control screw torque when applying an axial striking force to a rotating output bit.
Innovation Solution
A hammer drill design that incorporates a tightening-torque adjusting clutch, allowing users to deactivate the axial striking motion and control screw tightening torque by using a mechanism involving a motion conversion member, clutch spring, and direct coupling of rotational force to the output bit, enabling both drilling and screw tightening with adjustable torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a hammer drill applies axial striking force to a rotating output bit, then drilling performance is improved, but screw tightening capability deteriorates due to uncontrolled striking motion
Solution Approach 1:
The patent implements a dynamic mode-switching mechanism that allows the hammer drill to transition between striking mode (for drilling) and non-striking mode (for screw tightening). The clutch mechanism can be engaged or disengaged based on the operation required, providing dynamic adaptability to different tasks.
Solution Approach 2:
The patent makes the hammer drill multi-functional by enabling it to perform both drilling (with striking motion) and screw tightening (without striking motion) using the same device. The clutch mechanism allows a single tool to adapt to multiple functions that previously required separate tools.
2Ease of operation
If a hammer drill transmits only rotational force to the output bit, then screw tightening can be performed, but tightening torque cannot be controlled and over-tightening occurs
Solution Approach 1:
The patent introduces a clutch mechanism with adjustable engagement characteristics that allows control of the transmitted torque. By changing the clutch's engagement parameter (degree of engagement), the user can control the tightening torque to prevent over-tightening while maintaining adequate tightening force.
3Manufacturing precision
If a tightening-torque adjusting clutch is added to control screw torque, then screw tightening precision is improved, but device complexity increases
Solution Approach 1:
The patent merges the clutch mechanism with the existing hammer drill structure, integrating the torque control function into the current design rather than adding a completely separate system. The clutch is combined with the motor assembly and output shaft, sharing common components and space.
Solution Approach 2:
The clutch mechanism acts as an intermediary between the motor and the output bit, mediating the torque transmission. This intermediary component allows controlled torque transmission without requiring direct modification of the motor or output bit, simplifying the overall system architecture.
4Adaptability or versatility
If a single tool performs both drilling and screw tightening, then versatility is improved, but operational complexity increases
Solution Approach 1:
The patent uses a dynamic mode-switching mechanism that allows the user to easily transition between drilling and screw tightening modes. The clutch can be quickly engaged or disengaged during operation, providing simple and intuitive control for switching functions without complex procedures.
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 a single tool to perform both drilling and screw tightening tasks by controlling torque, eliminating the need for additional tools and preventing over-tightening, while ensuring efficient operation in both striking and non-striking modes.
Implementation Method 1
a motion conversion member which converts the rotational motion of the output bit into a reciprocating motion of the striker
Implementation Method 2
a tightening-torque adjusting clutch... involving a motion conversion member, clutch spring
Data Source
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AI summary
A hammer drill includes a motor; a spindle rotatingly driven by the motor and holding an output bit; a motion conversion member for converting rotational movement of the motor to reciprocating movement; a striker reciprocatingly driven by the motion conversion member for applying an axial striking force to the output bit; a striking-motion-releasing mechanism for releasing the striking force applying action exercised by the striker; and a tightening-torque adjusting clutch for interrupting the transfer of the rotational force to the output bit by increasing a load torque.