Handheld Tool Switchable Clutch and Threaded Drive
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Solution Overview
Problem
Existing hand-held power tools with motor-actuated clamping jaws often require complex designs and through holes, which can be difficult to produce while maintaining functionality and robustness, and lack efficient torque transmission for clamping and releasing operations.
Innovation Solution
A hand-held power tool design featuring a machine housing, motor, and tool holder with a switchable clutch that engages with the shaft or machine housing depending on the actuating element's position, allowing for compact and robust construction without the need for a through hole, and utilizing a threaded drive for efficient torque transmission through a blind hole mating thread.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a through hole with internal thread is provided in the tool holder for the threaded drive, then the clamping jaws can be clamped and released, but the design becomes complex and difficult to produce while restricting functionality
Solution Approach 1:
The threaded drive is extracted from the tool holder and relocated to the shaft. The shaft now contains the blind hole with internal thread, while the tool holder becomes a simpler component that only needs to accommodate the threaded drive externally. This extraction eliminates the complex through-hole requirement in the tool holder and simplifies its manufacturing.
Solution Approach 2:
The threaded drive is nested within the shaft structure rather than requiring a through-hole in the tool holder. The blind hole in the shaft contains the internal thread, and the threaded drive operates within this nested configuration, eliminating the need for complex through-hole machining in the tool holder.
2Device complexity
If the shaft is designed as a one-piece structure with blind hole, then torque transmission is efficient and design is simplified, but the threaded drive must be precisely integrated
Solution Approach 1:
The blind hole with internal thread is pre-formed in the shaft during shaft manufacturing, before final assembly. This preliminary integration ensures precise positioning and thread alignment, eliminating the need for complex post-assembly operations while maintaining manufacturing precision through controlled manufacturing processes.
3Reliability
If the switchable clutch is mounted on the tool holder, then the tool holder is alternatively coupled to the shaft and machine housing, but the design requires robust mounting without through holes
Solution Approach 1:
The coupling function is segmented between the switchable clutch mounted on the tool holder and the engagement elements on the shaft and machine housing. This segmentation allows the clutch to be mounted on the tool holder using simpler external features rather than requiring through-holes, improving manufacturability while maintaining reliable coupling through the distributed engagement points.
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 design enables efficient torque transmission for both working and clamping operations, ensuring the tool is firmly clamped with a controlled torque limiter, preventing incorrect operation and enhancing the tool's compactness and reliability.
Implementation Method 1
The threaded drive has a thread on the carriage and a mating thread on the shaft
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
The hand tool (1) has a machine housing (13), a motor (8), a shaft (9) that is driven by the motor (8), and a tool receptacle (3). The tool receptacle (3) is mounted on the shaft (9). The tool receptacle (3) has a receiving chamber (4) for receiving a tool (2) and a clamping jaw (6), which is guided in a slot (31) and protrudes into the receiving chamber (4), preferably a plurality of clamping jaws (6), for example three. A carriage (33), which is coupled to the clamping jaw (6), is provided with a threaded drive (32) that consists of a thread (34) on the carriage (33) and a counter thread (35) on the shaft (9). An actuation element (25), which can be displaced by a user between a first position (26) and a second position (27), is provided for selecting a working mode or for releasing/applying the clamping jaws (6). A switchable coupling (29) is mounted on the tool receptacle (3). The switchable coupling (29) engages alternately into the shaft (9) or into the machine housing (13) according to the positions of the actuation element (25).