Handheld Power Tool Torque Coupling for Impact Force Management
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Solution Overview
Problem
Handheld power tools with hammer mechanisms, such as jackhammers, experience inefficient momentum transfer when the cutter is not in contact with a workpiece, leading to empty strikes and potential damage due to unrestrained force absorption.
Innovation Solution
A torque coupling system with a return spring is integrated into the hammer mechanism, allowing the guide tube to move relative to the housing, which acts as a delay element to extend the momentum transfer and absorb forces, featuring coupling disks and a suspension system to manage impact and restrike forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the beater strikes the cutter without contact with workpiece (empty strike), then the momentum is transferred to the handheld power tool, but this causes harmful forces that may damage the tool
Solution Approach 1:
The patent applies beforehand cushioning by introducing a damping ring made of elastomer material at the front stop where the beater impacts during empty strikes. This damping ring is pre-installed to absorb and dissipate the impact forces before they can damage the tool housing, specifically cushioning the harmful effects of empty strikes on the tool structure.
Solution Approach 2:
The damping ring serves as an intermediary element between the beater and the tool housing. During empty strikes, the beater impacts the damping ring instead of directly transmitting forces to the housing. This intermediary component absorbs the shock and protects the structural integrity of the tool while allowing the hammer mechanism to continue operating.
2Reliability
If damping rings are added to the front stop, then the harmful forces are absorbed and tool protection is improved, but the device complexity increases
Solution Approach 1:
The patent employs a flexible elastomer damping ring instead of complex mechanical shock absorption systems. This thin-walled flexible component is simple in structure yet effective in absorbing impact forces, maintaining tool protection while avoiding significant increases in device complexity. The elastomer ring can be easily integrated into the existing front stop design.
3Object-affected harmful factors
If the guide tube is made movable along the working axis, then the torque coupling can extend momentum transfer and reduce peak forces, but the device complexity increases
Solution Approach 1:
The patent applies dynamics by making the guide tube movable along the working axis through a suspension system. This dynamic configuration allows the guide tube to shift position during operation, enabling the torque coupling to extend the momentum transfer time and reduce peak impact forces. The movable guide tube adapts to varying operational conditions, optimizing force distribution between the hammer mechanism and tool housing.
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 torque coupling system effectively absorbs and manages impact forces, reducing damage to the tool by interrupting torque transfer during restrike and utilizing the return spring for damping, enhancing the tool's operational safety and efficiency.
Implementation Method 1
The return spring acts on the suspension in the impact direction and acts on the second coupling disk in the direction opposite the impact direction
Implementation Method 2
Another embodiment extends directly to the return spring to utilize this for damping of the restriking of the blank strike
Implementation Method 3
The momentum transferred to the guide tube in the blank impact is introduced into the housing via the torque coupling. The torque coupling acts as a delay element. The return spring extends the transfer of momentum to the housing and thus also extends the resulting forces
Implementation Method 4
The guide tube is supported on the torque coupling in the impact direction. The guide tube may be displaced with respect to the housing in the impact direction, such that the torque coupling is shifted by the guide tube in a positively guided movement in relation to the housing
Data Source
AI summary
A handheld power tool is disclosed. The tool has a housing, a hammer mechanism and a torque coupling. The hammer mechanism includes a beater which is movably guided along the working axis in the guide tube. The guide tube is mounted in a suspension attached to the housing so that it is movable along the working axis. The torque coupling is mounted on the guide tube and is supported on the suspension in the impact direction. The guide tube is supported on the torque coupling in the impact direction. The guide tube may be shifted with respect to the housing in the impact direction such that the torque coupling is shifted relative to the housing through the guide tube in a positively guided manner.