揹負式割草機把手振動之量測與分析

Measurement and Analysis of Handle Vibration for Grass Trimmers and Brush Cutters

張振岳(Chen-Yueh Chang)

指導教授 ： 葉仲基

國立臺灣大學/生物資源暨農學院/生物產業機電工程學研究所/碩士(2011年)

https://doi.org/10.6342/NTU.2011.02947

摘要

據估計國內使用揹負式割草機之勞工約有一萬人，相較於其他形式之割草機，揹負式具有價格低廉、機動性高、易於操作及施作迅速等優點，故廣泛被用於園藝業與雜草清除等作業上。其所產生之振動主要透過把手，經由手臂傳遞至人體，此類振動稱為手－手臂振動，勞工長期使用會對手部之骨骼、神經及肌肉造成影響，形成職業傷害。

本研究以ISO 5349之規範為基礎，利用手腕換能器組、電源供應器與耦合器及動態記錄器構成一量測系統，並使用頻譜分析儀進行分析，再依據國際手－手臂振動相關規範，計算勞工每日工時與終身工作年數。

實驗結果顯示揹負式割草機之振動總加速度隨著引擎轉速上升而增加，割刀使用二片刀之振動量明顯大於尼龍繩。又根據歐盟規範，容許每日最大工作時數介於2.75到6.70小時；而以ISO 5349 計算終身工作年數，則介於3.28到5.23年，可做為揹負式割草機使用者之參考依據。再者，使用田口方法分析結果，在割草機型式、引擎轉速與刀片種類三個控制因子之下，對振動量貢獻的比例分別為5.80%、56.88%、24.94%，且在此因子條件下，最佳化參數為軟管式割草機、引擎轉速4500 rpm、以及使用尼龍繩。

關鍵字

手－手臂振動 ； 揹負式割草機 ； 頻率分析 ； 田口方法

並列摘要

There are estimated about ten thousands of workers who use grass trimmers and brush cutters in Taiwan. Grass trimmers and brush cutters are cheaper, more portable, easier operation than other forms of lawn mowers, so they are widely used in field of horticulture and weed removal. It will cause human body damage if a user operates a grass trimmer or brush cutter for a long time, because such machines will deliver vibration from the tool handle to the human arm. The type of vibration is also called hand - arm vibration. After operating a grass trimmer or brush cutter for a long time, it will also cause disease of skeleton, muscle and nerve.
This study is based on ISO 5349. The measurement system consists of a hand-arm vibration measurement set (Svantek SV51), a power supply/coupler (KISTLER 5134) and a data recorder (Kyowa RTP-50A). The measurement data are then analyzed by a signal analyzer (Bruel & Kjar Type 2035). The daily working time and career lifetime that based on international standard of hand-arm vibration can also be calculated.
The results show that the total acceleration of such machines increases when the engine speed increases. The vibration caused by the two blades as cutter is significantly greater than that caused by monofilament cutting device. According to Directive 2002/44/ec of the European parliament and of the council, the maximum daily working hours are between 2.75 to 6.70 hours. The career lifetime is between 3.28 to 5.23 years according to ISO-5349. By using Taguchi method, the contributions of total vibration with the factors of machine types, engine speed and cutting device account for 5.80%, 56.88% and 24.94% separately. And in this case, this method can also find an optimal operating parameter with using knap sack of brush cutters, 4500 rpm of engine speed and monofilament of cutting device.

並列關鍵字

hand-arm vibration,grass trimmer ； brush cutter ； frequency analysis ； Taguchi method

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