Eccentric Gear Rotation Angle Guide for Hand-Held Power Tools
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Solution Overview
Problem
Conventional random orbital sanders require modification of sanding discs to maintain rotational angle position, limiting the use of conventional sanding discs and complicating tool handling due to the need for external braking mechanisms.
Innovation Solution
A hand-held power tool with a rotation angle guide means integrated into the eccentric gear, allowing direct coupling and decoupling with the tool shaft, enabling easy switching between eccentric modes without modifying the sanding or polishing pads, and incorporating a balancing mechanism to reduce vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If rotation angle guide means are integrated into the eccentric gear, then the tool holder's rotational angle is stabilized and conventional sanding discs can be used, but the device complexity increases
Solution Approach 1:
The rotation angle guide means are integrated directly into the eccentric gear structure, combining the functions of eccentric motion generation and rotation angle guidance into a single unified component. This eliminates the need for separate external guidance mechanisms and allows conventional sanding discs to be used without modification.
Solution Approach 2:
A guide element with linear guides is introduced as an intermediary component between the eccentric gear and the tool holder. This guide element stabilizes the rotational angle by constraining the tool holder's rotation while maintaining the eccentric motion, effectively mediating between the two components.
2Adaptability or versatility
If switching means are added to switch between eccentric modes, then the adaptability is improved, but the device complexity increases
Solution Approach 1:
The switching means enable dynamic reconfiguration of the eccentric gear system, allowing transition between different operational modes (free rotation mode and guided rotation mode). The system can adapt its behavior in real-time based on operational requirements, with the guide element being movable between engaged and disengaged positions.
3Stability of the object's composition
If the rotation angle guide means are coupled directly to the tool shaft, then the rotational angle stabilization is achieved, but the manufacturing precision requirements increase
Solution Approach 1:
The rotation angle guide means are segmented into separate components (guide element, linear guides, engagement contours) that can be manufactured independently with standard tolerances. This segmentation reduces the cumulative precision requirements compared to a fully integrated monolithic design.
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 the use of conventional sanding discs, improves handling by stabilizing the tool holder's rotational angle, and reduces vibrations through balanced operation, enhancing user safety and tool efficiency.
Implementation Method 1
a guide element (70, 71) with two linear guides (68, 69) for guiding in two directions (l, q) which are at an angle to one another, in particular at right angles
Implementation Method 2
The rotational angle guide means are preferably accommodated in a gear housing (60) of the eccentric gear (27).
Data Source
Figure 1~2
Figure 3~6
Figure 8~10b
AI summary
The invention relates to a hand-held power tool (10) with a drive motor (17) for driving a tool holder (23) for a tool (24, 25) via an eccentric gear (27), which has a drive shaft (57) rotatably coupled to the drive motor (17) and rotatable about a drive axis (36), on which a tool shaft, on which the tool holder (23) is arranged, is mounted eccentrically to the drive axis (36) by means of a tool shaft bearing (61, 62) for carrying out eccentric movements, wherein the tool shaft (26) performs rotational movements in at least one rotation-eccentric mode (F, Z) due to bearing friction of the tool shaft bearing (61, 62) during rotation of the drive shaft (57) and/or by means of a forced rotation guide (64).and wherein, for an eccentric-only mode (N), a rotational angular position of the tool holder (23) relative to a machine housing (11) of the hand-held machine tool (10) can be set to a rotational angular sector limited by rotational angular guide means (67). In an eccentric-only mode (N), the rotational angular guide means (67) engage with the tool shaft (26) to guide the tool shaft (26). The eccentric gear (27) has switching means (85) for switching the rotational angular guide means (67) into and out of the eccentric-only mode (N).