Hand-Held Circular Saw Protective Wedge and Safety Brake
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Solution Overview
Problem
Hand-held circular saws pose a risk of injury due to exposure of the cutting edge when the protective pendulum guard is forced into the housing during operation, potentially causing contact with the user.
Innovation Solution
A protective wedge is rotatably mounted around the saw blade's axis of rotation, spring-loaded to enclose the cutting edge during sawing, and a touch sensor system with a safety device, including a clutch and saw blade brake, is implemented to prevent accidental contact and ensure safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pendulum guard is used to protect the saw blade, then safety is improved when the saw is not in use, but the cutting edge becomes exposed during sawing operations causing safety risks
Solution Approach 1:
The protective wedge is designed to rotate dynamically between two positions: enclosed position during sawing operations and open position when the saw is not in use. This dynamic movement allows the system to adapt to different operational states, providing protection when needed while maintaining accessibility during operation.
Solution Approach 2:
The protective wedge acts as an intermediary element between the user and the cutting edge. It selectively blocks access to the cutting edge during sawing operations while allowing full access when the saw is idle, thus mediating the safety risk without compromising operational functionality.
2Reliability
If the protective wedge is spring-loaded to maximize enclosure, then safety is improved, but the mechanism complexity increases
Solution Approach 1:
The protective wedge is equipped with a spring mechanism that automatically returns it to the enclosed position after it has been pushed forward during sawing operations. This self-service mechanism eliminates the need for manual intervention or complex control systems, achieving maximum enclosure through a simple spring-loaded design.
3Reliability
If the protective wedge thickness equals the saw blade thickness, then the wedge can be guided in the saw groove for better protection, but the wedge design becomes more constrained
Solution Approach 1:
The protective wedge is designed with a thickness that matches the saw blade thickness specifically in the region that contacts the saw groove. This localized dimensioning allows the wedge to be precisely guided in the groove during sawing operations while maintaining manufacturability and structural integrity.
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 protective wedge effectively prevents contact with the cutting edge, and the safety device enables rapid braking of the saw blade upon detection of contact, significantly reducing the risk of injury and ensuring safe operation.
Implementation Method 1
the protective wedge for enclosing the cutting edge of the replaceable saw blade is spring-loaded
Implementation Method 2
The protective wedge is equipped with a touch sensor
Implementation Method 3
The safety device preferably includes a saw blade brake
Data Source
Figure 1~2
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AI summary
The invention relates to a circular saw (100), in particular a hand-held circular saw, having a housing (110) and a drive unit, at least some sections of which are arranged in the housing (110) and with which a tool holder (140) for an exchangeable saw blade (130) is associated, the drive unit (710) being designed to rotationally drive the exchangeable saw blade (130) about an associated axis of rotation (140). In said circular saw a blade guard (150) is associated with the exchangeable saw blade (130), which blade guard is mounted in the housing (110) for rotation about the associated axis of rotation (140) and which extends around a cutting point (132) of the exchangeable saw blade (130) at least during a sawing operation in such a way that contact with the cutting point (132) can be at least substantially prevented.