Vibrating Hand Tool Locking Switch Linkage Design
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Solution Overview
Problem
Existing hand-held power tools with vibration-decoupled guide handles face complexity and space constraints in implementing a technologically simple control for the locking switch of the motor switch, particularly in switching between percussive and rotating operating modes.
Innovation Solution
A shifting linkage with a rigid stop and a flexible leg, pivotably mounted on the percussion mechanism assembly, allows for a fatigue-free and space-saving locking mechanism, where the flexible leg absorbs elastic deformation, enabling smooth operation across different modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rigid shifting linkage is used to control the locking switch, then the locking function is reliable, but the device complexity and space requirements increase
Solution Approach 1:
The shifting linkage is divided into two distinct segments: a rigid leg (16a) that forms the stop and provides reliable positioning, and a flexible leg (16b) that connects to the operating mode selector switch. This segmentation allows each part to perform its specific function optimally while reducing overall complexity compared to a fully rigid linkage.
Solution Approach 2:
The linkage transitions from a static rigid structure to a dynamic system where the flexible leg can deform elastically. The flexible leg changes its physical state between rigid and flexible based on operational requirements, allowing it to absorb movements and reduce stress while maintaining control functionality.
2Strength
If a rigid shifting linkage is used, then the structural integrity is maintained, but the space consumption and material usage increase
Solution Approach 1:
The linkage is segmented into rigid and flexible portions, allowing the rigid leg to maintain structural integrity where needed while the flexible leg minimizes material usage and space occupation through its deformable nature.
Solution Approach 2:
The flexible leg is designed as a thin, deformable element that can bend and absorb movements. This flexible component replaces what would traditionally require a bulky rigid structure, significantly reducing the volume and material requirements while maintaining functional integrity.
3Reliability
If the guide handle is vibration-decoupled from the hammer mechanism assembly, then the guide handle durability is improved, but the control of the locking switch becomes more complex
Solution Approach 1:
The control system is segmented with the rigid leg providing stable positioning independent of vibrations, while the flexible leg absorbs vibrational movements. This allows the locking switch control to function reliably even when the guide handle is vibration-decoupled from the hammer mechanism.
Solution Approach 2:
The flexible leg acts as an intermediary element between the vibration-prone hammer mechanism and the locking switch control. It mediates the transmission of movements, filtering out harmful vibrations while allowing necessary control movements to pass through.
4Volume of moving object
If a flexible leg is used in the shifting linkage, then the space and material usage are reduced, but the structural strength may be compromised
Solution Approach 1:
The linkage is segmented so that the rigid leg (16a) provides the necessary structural strength and positioning, while the flexible leg (16b) provides flexibility and space efficiency. Each segment is optimized for its specific function, ensuring overall strength is not compromised.
Solution Approach 2:
Different parts of the linkage have different mechanical properties: the rigid leg has high stiffness and strength for positioning, while the flexible leg has lower stiffness for space efficiency and vibration absorption. This local differentiation of qualities allows the system to achieve both strength and compactness.
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
This solution provides a technologically simple and fatigue-free locking function in vibration-decoupled guide handles, ensuring efficient operation in both chiseling and rotary drilling modes without material or space wastage, while maintaining mechanical integrity through elastic angle absorption.
Implementation Method 1
the flexible leg forms a film hinge near the bend, whereby the change in angle caused by the axial displacement of the flexible leg is absorbed elastically and thus without damage
Implementation Method 2
the limp leg forms another film hinge near the connection to the operating mode selector switch, whereby the change in angle of the limp leg caused by the pivoting of the rigid leg is absorbed elastically and thus without damage
Data Source
Figure 1
Figure 2~3
AI summary
A hand-held power tool that at least partially impacts and rotates along an impact axis (A), with a guide handle vibration-isolated with respect to a vibrating impact assembly (2) and a motor switch for motor control, to which a locking switch (7) is assigned for locking, which is movable within a switching range (X), wherein an operating mode selector switch (2) is arranged in the impact assembly (2), which moves a switching linkage (9) having a stop (10) that projects into the switching range (X) in a rotating operating mode, wherein the switching linkage (9) is angled with two legs (16a, 16b), wherein a rigid leg (16a), which forms the stop (10) and is pivotably mounted at a pivot point (17) on the impact assembly (2), and the other axially extending leg connected to the operating mode selector switch (3). (16b) is formed in a flexible manner.