Tool Attachment Locking Sleeve for Backlash-Free Torque Transmission
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Solution Overview
Problem
Existing tool attachments for handheld power tools require a significant radial and tangential play between the drive shaft and the tool holder to allow engagement, leading to a less secure locking mechanism.
Innovation Solution
A tool attachment design that incorporates a sleeve-like actuating member surrounding the drive shaft, utilizing spring-loaded locking sleeves to reduce play and ensure secure centering and torque transmission, with a locking section that includes a bayonet connection for secure fastening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a large radial and tangential clearance is present between the drive shaft and tool holder to allow engagement, then the drive shaft can engage in the tool holder when locked, but the locking mechanism becomes less secure and backlash-free fixation cannot be achieved
Solution Approach 1:
The locking mechanism is divided into two independent functional parts: a first locking sleeve for radial locking and a second locking sleeve for axial locking. This segmentation allows each locking element to perform its specific function optimally - the first locking sleeve eliminates radial and tangential play while the second locking sleeve provides axial positioning, together achieving secure backlash-free fixation without requiring large clearances for engagement
Solution Approach 2:
The actuating element serves as an intermediary mechanism that coordinates the interaction between the drive shaft and tool holder. It transmits the unlocking force from the user's operation to the first locking sleeve, enabling controlled displacement that reduces clearance while maintaining engagement capability. This intermediary mechanism allows smooth transition between locked and unlocked states without requiring excessive clearance
2Manufacturing precision
If spring-loaded locking sleeves are used to reduce play, then backlash-free fixation is achieved, but the device complexity increases
Solution Approach 1:
The locking mechanism utilizes spring elements that automatically engage and disengage the locking sleeves without requiring complex control systems. The springs provide the necessary force to maintain locking engagement and enable automatic resetting when the actuating element is operated. This self-service mechanism achieves precise backlash-free fixation while minimizing complexity by eliminating the need for motors, sensors, or complex control logic
Solution Approach 2:
Multiple locking functions are merged into a compact integrated structure. The first and second locking sleeves are combined with spring elements and the actuating element in a unified locking section that performs both radial and axial locking simultaneously. This merging reduces the overall space required and simplifies the mechanism compared to having separate locking systems for each direction
3Length of moving object
If the overall length of the tool attachment is reduced, then compactness is improved, but the mounting and locking mechanisms become more constrained
Solution Approach 1:
The locking sleeves and spring elements are nested within each other in a compact arrangement. The first locking sleeve is positioned within the tool holder, the second locking sleeve is nested within the first, and the spring elements are contained within the locking sleeve structures. This nesting arrangement minimizes the axial length of the tool attachment while maintaining all necessary mounting and locking functions
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 design achieves a backlash-free, radially and tangentially secure fixation of the tool attachment on the handheld power tool, allowing for efficient torque transmission and easy mounting, while maintaining a compact overall length.
Implementation Method 1
a first locking sleeve pre-tensioned by a first spring element in an axial direction pointing away from the hand-held power tool
Implementation Method 2
a second locking sleeve arranged, axially displaceable against a spring force of a second spring element to release at least one locking element
Data Source
Figure 1
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Figure 3
AI summary
The attachment has a locking portion locked at a fastening interface (150) of hand-held power tools (100). A tool receiver (140) is provided with a receiving body (147) for arranging an insert tool (170). A lock bush (149) is linked by a first spring element along axial direction (199) and pointed away from the hand-held power tools. An operating element i.e. sintered bearing, is provided in the attachment. The lock bush is fastened opposite to the spring element to displace spring force toward axial direction of the hand-held power tools.