Impact Tool Hammer Assembly Mode Switching
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Solution Overview
Problem
Existing impact tools require multiple power tools for different operations, leading to increased size and cost, and can damage brittle materials due to generated impact force during drilling.
Innovation Solution
An impact tool design featuring a main hammer and a sub hammer with a switching mechanism using a ball and switch ring to transition between impact and drill modes, allowing for compact size and reduced cost without compromising rotary impact force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a connecting sleeve is arranged peripherally around the hammer to enable mode switching, then the impact tool can provide both impact and drill modes, but the size of the impact mechanism increases in the diametrical direction
Solution Approach 1:
The sub hammer is nested inside the main hammer, with the sub hammer's peripheral wall fitting within the main hammer's outer periphery. The connecting member is positioned within the space between the sub hammer's inner peripheral surface and the main hammer's outer periphery, effectively utilizing the internal space without increasing the overall diametrical size of the impact mechanism.
Solution Approach 2:
The hammer is divided into two separate hammers (main hammer and sub hammer) that can operate independently or together. The connecting member selectively connects these segmented components to achieve different operational modes, allowing versatility without requiring a peripheral connecting sleeve that would increase diametrical dimensions.
2Adaptability or versatility
If a connecting sleeve and flange are added to enable mode switching, then the impact tool can provide both impact and drill modes, but the cost of the impact tool increases
Solution Approach 1:
The sub hammer serves multiple functions: it acts as a protective cover for the main hammer, provides a mounting structure for the connecting member, and participates in the impact generation when connected. This multi-functionality eliminates the need for separate dedicated components like a peripheral connecting sleeve and flange, reducing part count and manufacturing cost.
Solution Approach 2:
The functions of protection, mode switching, and impact generation are merged into a integrated structure where the sub hammer and connecting member work together. The connecting member simultaneously achieves mode switching and structural connection, eliminating the need for separate flange and connecting sleeve components.
3Ease of operation
If the hammer is designed to always rotate with the spindle in drill mode, then drilling operation can be performed, but the impact tool cannot provide rotary impact force
Solution Approach 1:
The connection between the sub hammer and main hammer is made dynamic through the movable connecting member. In drill mode, the connecting member disconnects them allowing independent rotation. In impact mode, the connecting member connects them enabling unitary rotation and impact generation. This dynamic reconfigurability allows the system to adapt its rotational characteristics based on operational requirements.
Data Source
Figure 1
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Figure 3
AI summary
In an impact tool (1), a hammer is divided into an inner-side main hammer (40) engageable with or disengageable from an anvil (10) and an outer-side sub hammer (42) having a peripheral wall (43) covering an outer periphery of the main hammer (40) and formed as a separate member. The sub hammer (42) is rotatably disposed in a rearward position, and the peripheral wall (43) is engageable with the main hammer (40) so that the main hammer (40) and the sub hammer (42) are unitarily rotatable. A connecting member (56) is disposed between the main hammer (40) and the peripheral wall (43) in such a manner as to be movable between a connecting position and a disconnected position using a switching device. When the connecting member (56) is moved in the connecting position, a drill mode is selected, in which retraction of the main hammer (40) is restricted.