Handheld Power Tool Three Suspension Assemblies Kickback Torque
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Handheld power tools with a center of mass outside the working axis experience significant kickback torque, which is not effectively mitigated by existing suspension systems, leading to user discomfort and reduced control during drilling and chiseling operations.
Innovation Solution
A handheld power tool design featuring three suspension assemblies with a slanted handle axis, where the first assembly is closer to the working axis, the second has a lever arm with a guide and spring for decoupling vibrations, and the third allows parallel movement of the machine housing relative to the handle, reducing torque transmission and enhancing vibration damping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the handle is rotatably suspended around the center of mass, then the torque cannot act upon the handle, but the vibration damping along the handle axis becomes coupled with the working axis connection
Solution Approach 1:
The suspension system is divided into three separate suspension assemblies instead of one complex assembly. Each assembly handles specific degrees of freedom: the first two assemblies constrain rotational movement around the center of mass to reduce torque, while the third assembly allows translational movement along the working axis for vibration damping. This segmentation resolves the contradiction by distributing functions across multiple simple components rather than one complex coupled system.
Solution Approach 2:
The third suspension assembly introduces a new degree of freedom by allowing movement along the working axis (translational dimension) while the first two assemblies handle rotational constraints. This dimensional separation decouples the vibration damping function from the torque reduction function, allowing each to optimize independently without interfering with the other.
2Object-affected harmful factors
If the handle axis is made perpendicular to the working axis, then the torque transmission is reduced, but the vibration isolation between handle axis and working axis becomes difficult to achieve
Solution Approach 1:
The suspension system is segmented into three assemblies with specific orientations and functions. The first suspension assembly handles constraints near the working axis, the second assembly with the lever arm oriented along the handle axis handles rotational constraints, and the third assembly handles translational movement along the working axis. This segmentation allows the perpendicular handle axis configuration to reduce torque while the third assembly independently provides vibration isolation along the working axis.
Solution Approach 2:
The third suspension assembly acts as an intermediary element that mediates between the handle and machine housing along the working axis. It allows the handle to move freely along the working axis to damp vibrations while the perpendicular handle axis configuration reduces torque transmission. This intermediary component enables both benefits to coexist by decoupling the two functions.
3Ease of operation
If the center of mass is positioned outside the working axis, then the tool provides better balance and control, but kickback effects create significant torque around the center of mass
Solution Approach 1:
The suspension system is divided into three assemblies that collectively handle the torque reduction function. The first suspension assembly is arranged closer to the working axis, the second suspension assembly has a lever arm along the handle axis, and the third suspension assembly is offset along the working axis. This segmented approach allows the center of mass to remain outside the working axis for better balance while the distributed suspension assemblies effectively counteract the kickback torque through their combined constraints.
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 effectively isolates vibration damping along the handle axis from the working axis, reducing kickback torque and enhancing user control, particularly in heavy tools like 10 kg drilling and chiseling hammer drills, by optimizing stiffness and movement freedom in both axes.
Implementation Method 1
The second suspension assembly has a lever arm that runs along the handle axis. The second end of the lever arm in the guide can be forcibly deflected against a spring means along a trajectory that is slanted or perpendicular to the working axis.
Implementation Method 2
By means of the guide, the second suspension assembly isolates the vibration damping along the handle axis from the requisite connection along the working axis.
Implementation Method 3
The pivot bearing reduces the transmission of the torque of the handheld power tool around its center of mass.
Data Source
AI summary
The handheld power tool has a tool socket to hold a chiseling tool on a working axis and a striking mechanism that acts upon the tool in the striking direction. The striking mechanism is arranged in a machine housing. A handle is oriented along a handle axis that is perpendicular to the working axis and that is installed on the machine housing by three suspension assemblies. The second suspension assembly has a lever arm that runs along the handle axis. The first end of the lever arm is attached to a machine housing and to a handle. A guide is attached to the other machine housing and handle. The second end of the lever arm in the guide can be forcibly deflected against a spring along a trajectory that is slanted or perpendicular to the working axis.