Eccentric Lever Handle Locking Mechanism for Machine Tools
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Solution Overview
Problem
Hand-held machine tools often have issues with handle adjustment, as the clamping screw tension is difficult to determine, and frequent adjustments are cumbersome, especially when using tools are not available.
Innovation Solution
The machine tool incorporates an eccentric lever with defined locking and release positions, allowing for quick adjustment without tools, using a cam contour to engage or disengage the handle with the machine tool housing, and an adjustable stop to manage clamping force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a clamping screw is used to secure the handle, then the handle connection is reliable, but the adjustment process becomes complex and time-consuming
Solution Approach 1:
The patent replaces the traditional screw-based clamping mechanism with an eccentric lever mechanism. The eccentric lever uses cam-shaped contours to generate clamping forces, substituting the threaded mechanical system with a cam-based system that achieves the same securing function through rotational movement rather than threading.
Solution Approach 2:
The patent changes the operational parameter from rotational threading (multiple turns of a screw) to a limited angular rotation of the eccentric lever. The cam contour geometry transforms the lever's rotational motion into linear clamping motion, reducing the adjustment cycles from many screw turns to a single lever pivotation.
2Strength
If a clamping screw is used to adjust the handle, then secure connection is achieved, but the number of adjustment turns increases
Solution Approach 1:
The screw threading mechanism is replaced with an eccentric lever and cam contour system. The cam contour is designed to convert the lever's rotational movement into effective clamping motion, achieving the same securing strength with significantly reduced movement cycles.
Solution Approach 2:
The cam contour is pre-designed with specific geometry that automatically generates the necessary clamping force during the lever's rotation. The shape of the cam contour ensures that the clamping action is built into the mechanism's geometry, eliminating the need for multiple adjustment turns.
3Stability of the object's composition
If the clamping screw tension is increased to prevent loosening, then connection stability improves, but the complexity of determining sufficient tension increases
Solution Approach 1:
The eccentric lever mechanism is designed to be self-locking through the geometry of its cam contour. The contour shape creates a mechanical interlock that maintains clamping force without requiring precise user judgment or additional locking components. The mechanism automatically maintains sufficient tension through its inherent geometric design.
Solution Approach 2:
The patent changes the control parameter from indefinite screw tension (requiring user judgment) to a defined angular position of the eccentric lever. The cam contour translates a specific lever angle into a determined clamping force, making the tension level objectively defined by the mechanism's geometry rather than subjective user assessment.
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
Enables secure and ergonomic handle adjustment within seconds, reducing wear and improving user experience by clearly defining handle states and allowing for precise force control.
Implementation Method 1
the association between the states of the eccentric lever and the handle is therefore via the at least one cam contour of the eccentric lever
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
The invention relates to a machine tool (2), comprising a machine tool housing (4) and a handle assembly (6), which can be adjusted in the angular position thereof relative to the machine tool housing (4), the handle assembly (6) containing: at least one handle (10) having at least one coupling element (26), which handle, relative to at least one counter coupling element (30) of the machine tool housing (4), is adjustable in the angular position of said handle and is linearly movable along a movement axis (X), and a locking mechanism (8), which is designed to fix the handle (10) in a coupled state, in which the coupling element (26) of the handle (10) is in engagement with the counter coupling element (30) of the machine tool housing (4), such that the handle (10) and the machine tool housing (4) are fixedly connected to each other, and to release the handle in an uncoupled state, in which the coupling element (26) of the handle (10) is disengaged from the counter coupling element (30) of the machine tool housing (4), such that the handle (10) can be adjusted in the angular position thereof relative to the machine tool housing (4), the locking mechanism (8) containing: an eccentric lever (36) having a first end (44) and a second end (46), which eccentric lever can be reversibly pivoted about a pivot axis (S), which extends perpendicularly to the movement axis (X) and is provided in the region of the second end (46), between a locking position and a release position, at least one bearing element (38) for pivotably supporting and retaining the eccentric lever (36), and a stop (74) for the eccentric lever (36) for defining a predetermined distance between the pivot axis (S) and the counter coupling element (30) of the machine tool housing (4), at least one cam contour (52) being provided at the second end (46) of the eccentric lever (36), the center point (54) of which cam contour lies outside of the pivot axis (S), such that the handle (10) is transferred into the coupled state by pivoting of the eccentric lever (36) into the locking position and is released into the uncoupled state by pivoting of the eccentric lever (36) into the release position.