Automatic Retarding Device for Handheld Cutting Machines
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Solution Overview
Problem
Handheld cutting machines, such as cut-off saws, experience prolonged slowing down to idle speed due to reduced energy loss in modern belts, making existing retarding devices less secure and more complex, especially when they rely on manual or automatic control mechanisms.
Innovation Solution
A retarding device that activates when a predetermined speed or torque is reached, utilizing brake shoes and elastic springs to rapidly slow and stop the cutting tool, providing a reliable and secure braking mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a modern thin belt (poly-v belt) is used to reduce energy loss, then energy efficiency is improved, but the retarding function is reduced and slowing down takes more time
Solution Approach 1:
The retarding function is segmented from the belt transmission system and implemented as a separate, dedicated braking mechanism. This allows the thin belt to maintain its energy efficiency while the separate retarding device provides sufficient braking power independently.
Solution Approach 2:
A separate retarding device acts as an intermediary between the engine and the cutting tool, providing the necessary braking function without interfering with the efficient power transmission of the thin belt during normal operation.
2Reliability
If a separate retarding device is added to improve braking function, then retarding performance is improved, but device complexity increases
Solution Approach 1:
The retarding device is merged with existing components of the cutting machine, such as the engine flywheel or transmission elements, rather than being a completely separate addition. This integration reduces overall complexity while maintaining reliable retarding function.
Solution Approach 2:
Existing components are designed to serve multiple functions: the engine flywheel not only stores rotational energy but also serves as the braking surface for the retarding device, eliminating the need for separate dedicated components.
3Ease of operation
If manually controlled retarding devices are used, then retarding control is achieved, but machine security is reduced
Solution Approach 1:
The retarding device is designed to activate automatically based on predetermined conditions (speed or torque thresholds) without requiring manual intervention. The system monitors its own state and engages braking when safety thresholds are exceeded, ensuring consistent and reliable operation.
Solution Approach 2:
The retarding device incorporates feedback mechanisms that continuously monitor speed and torque, automatically engaging the braking function when predetermined thresholds are reached, thereby eliminating human error and ensuring consistent safety performance.
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 ensures rapid and controlled slowing of the cutting tool, enhancing safety and simplifying the design by automatically engaging the braking mechanism based on predetermined speed or torque thresholds, addressing the inefficiencies and complexity of existing systems.
Implementation Method 1
a retarding device for a rotational cutting machine (1) comprising a brake shoe (12) and an elastic means (13) arranged to exert a retarding action on the brake shoe (12) when a predetermined value of the speed is reached or when a predetermined value of a torque of rotation is reached
Data Source
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AI summary
The present invention is related to a retarding device for a hand held cutting machine having a housing (1) and a drive engine, which drives a transmission comprising a number of transmission members (3', 2) and driving a rotational or semi rotational cutting tool. The retarding device comprises brake means (12, 17) arranged to be in close relation with the transmission and for actuating a retarding force on a transmission member (2), said brake means being arranged to automatically put a retarding force on said transmission member when the speed of rotation or the torque of rotation of said transmission member falls below a predetermined value.