Oscillating Tool Holding Mechanism Axial Locking

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Solution Overview

Problem

Existing work tools require space for radial movement of balls or clamp members to hold the clamp shaft relative to the spindle, which is inefficient and lacks a rational structure for fixation.

Innovation Solution

A work tool with a holding mechanism that biases the clamp shaft upward, using a locking part and holding shaft with a biasing spring to securely attach the clamp shaft to the spindle, minimizing the need for radial space and simplifying the structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If balls or clamp members are used to hold the clamp shaft relative to the spindle, then the clamp shaft can be fixed, but a space is required for radial movement of these engagement members

Engineering Contradiction:
Improvefixation of clamp shaftVSAvoidradial space requirement
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

Instead of using balls or clamp members that move radially to engage with the clamp shaft, the invention uses a holding shaft that moves axially (in the direction of insertion/removal) to engage with a locking part on the clamp shaft. This inverts the conventional approach by changing the movement direction from radial to axial, thereby eliminating the need for radial space while maintaining reliable fixation.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The invention transitions the engagement mechanism from radial movement (2D plane perpendicular to shaft axis) to axial movement (1D line along shaft axis). By changing the dimension of movement from radial to axial, the design eliminates the volume requirement for radial space while achieving the same fixation function.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If a holding mechanism with biasing spring is used to fix the clamp shaft, then the structure becomes more stable, but the device complexity increases

Engineering Contradiction:
Improvestability of clamp shaft holdingVSAvoidholding mechanism structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The holding shaft is equipped with a biasing spring that automatically biases the holding shaft in the axial direction to engage with the locking part on the clamp shaft. This self-servicing mechanism maintains stable holding without requiring additional control systems or complex actuation mechanisms, achieving reliability while keeping the structure relatively simple.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention uses a biasing spring to change the positional parameter of the holding shaft dynamically. The spring provides continuous axial force to maintain engagement between the holding shaft and the locking part, ensuring stable holding through parameter change (position maintenance) rather than complex mechanical constraints.

Inventive Principle:
Principle #35Parameter changes

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 solution provides a stable and space-efficient method to fix the clamp shaft relative to the spindle, enhancing the tool's operational efficiency and ease of assembly by eliminating the need for radial movement of engagement members.

Implementation Method 1

a holding mechanism (7) which is configured to fixedly hold the clamp shaft (6) relative to the spindle (5), while the clamp shaft (6) is biased upward by the holding mechanism (7)

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP3593950B1Work tool
Publication Date: 2023.06.14 MAKITA CORP
  • EP3593950B1 patent drawingFigure 1
  • EP3593950B1 patent drawingFigure 2
  • EP3593950B1 patent drawingFigure 3

AI summary

An oscillating tool (1) includes a spindle (5), a clamp shaft (6), a holding shaft (71), a locking part (67) and a biasing spring (77). The holding shaft (71) has a locking hole (714). The locking part (67) is rotatable around a driving axis (A1) relative to the holding shaft (71) between an unlock position in which the locking part (67) is allowed to pass through the locking hole (714) and a lock position in which the locking part (67) is engaged with the holding shaft (71). The locking part (67) allows the clamp shaft (6) to move in an up-down direction relative to the holding shaft (71) in the unlock position, while preventing the clamp shaft (6) from moving downward relative to the holding shaft (71) in the lock position. The holding shaft (71) is configured to fixedly hold the clamp shaft (6) relative to the spindle (5) while being biased upward by the biasing spring (77) with the locking part (67) in the lock position.