Hand-held Power Tool Protected Transmission
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Solution Overview
Problem
Existing portable electric tools, such as pruning shears, face challenges in protecting the ball screw-nut mechanism from debris and dust, which can lead to rapid wear and blocking, and require precise casing conformations that complicate design and maintenance.
Innovation Solution
A separate protective casing for the ball screw-nut mechanism, driven by the nut or screw connected to the cutting member, forms a closed space with a sliding seal to prevent dirt entry, allowing independent shaping and ensuring the main casing can be designed for comfort and ventilation without compromising protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the main housing is configured to protect the transmission, then protection against debris is improved, but the design complexity and difficulty of adjustment increase
Solution Approach 1:
The protective housing is separated into two independent parts: the main housing and a separate protective casing for the ball screw-nut mechanism. This segmentation allows each component to be optimized independently - the main housing for ergonomic handling and ventilation, and the protective casing specifically for debris protection, thereby reducing overall design complexity while maintaining protection reliability.
Solution Approach 2:
A separate protective casing acts as an intermediary element between the transmission mechanism and the external environment. This intermediate protective structure shields the ball screw-nut mechanism from debris without requiring the main housing to be complexly configured, thus resolving the contradiction between protection and design simplicity.
2Ease of operation
If the main housing is adjusted precisely on the blades, then blade movement is not hindered, but protection against debris entry is reduced
Solution Approach 1:
By separating the protective function into an independent casing for the ball screw-nut mechanism, the main housing can be precisely adjusted on the blades to ensure smooth operation without compromising debris protection. The protective casing independently handles the debris protection function while the main housing focuses on ergonomic and operational requirements.
3Device complexity
If the protective casing is integrated into the main housing, then structure is simplified, but protection effectiveness is reduced
Solution Approach 1:
The protective casing is designed as a separate component rather than being integrated into the main housing. This segmentation enables the protective casing to be specifically optimized for debris protection with appropriate sealing and access features, while the main housing remains optimized for handling and ventilation, thereby maintaining both structural simplicity and protection effectiveness.
4Ease of repair
If the tool is disassembled for maintenance, then access to internal components is improved, but protection against debris is lost
Solution Approach 1:
The protective casing can be independently removed or accessed during maintenance operations without requiring complete disassembly of the tool. This segmented design allows maintenance personnel to access the ball screw-nut mechanism through the protective casing while maintaining protection against debris when the casing is in place, thus resolving the contradiction between ease of repair and debris protection.
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 effectively protects the ball screw-nut mechanism from debris and dust, enabling reliable operation, simplifying production, and allowing for pre-assembly testing and maintenance without compromising the tool's handling or ventilation.
Implementation Method 1
a sliding seal cooperating with an internal face of the protective casing, the sliding seal being driven by one of the nut and screw connected to the cutter
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention concerns a hand-held power tool comprising a motor (14), a cutting member (26) and a transmission (16, 20, 22) linking the cutting member to the motor, the motor and the transmission being housed in a main housing (10), the transmission comprising a ball screw/nut mechanism (20) with a screw (42) and a nut (40), one of the screw and the nut being rotatably engaged with the motor, and the other of the screw and the nut being linked to the cutting member, according to the invention, the tool comprises a protective housing (50) for protecting the ball screw/nut mechanism, separate from the main housing, and a sliding seal (52) cooperating with an inner face of the protective housing (50), the sliding seal being driven by one of the nut (40) and the screw (42) linked to the cutting member, the sliding seal (52) being rigidly connected respectively to one of a sleeve (54) covering the nut and a cap (80) protecting the screw (42).