目前國內使用揹負式割草機的勞工估計有近萬人，由於該型割草機具有價格便宜、操作簡易及施作迅速等優點，故仍為園藝工作清除雜草使用相當普遍的割草或除草工具。本研究主要針對該種割草機進行把手振動之現場量測調查，瞭解目前使用揹負式割草機於操作者握把處產生之振動量，並與歐盟標準以及我國法規相比較。測試用之揹負式割草機有軟管式與硬管式兩種，刀具分別為牛筋繩與二片刀，使用之量測儀器則為手腕換能器組。量測結果顯示：振動總加速度介於2.41與5.74 m/s^2之間，日常8小時等效暴露量皆超過所建議之行動閾值，但未達限制閾值；振動最大均方根（Root Mean Square, RMS）加速度為3.79 m/s^2，根據勞工安全衛生設施規則第302條，每日之允許暴露時間為4小時以上、未滿8小時。引擎轉速與振動量有正相關性，引擎轉速越高，則總加速度越大；刀具選用也會影響振動量，在使用同一台割草機的情況下，使用二片刀之振動大於使用牛筋繩。

The number of users of brush cutters and grass trimmers is about 10,000 in Taiwan. The advantages of these kinds of machines are cheap price, easy use and fast operation. Therefore, they are widespread hand-held power tools for mowing in the field of horticulture and remove of weeds. The objective of this study is to measure the vibration at handle when users of such machines are operating in field. The results show that the overall vibration acceleration is between 2.41 and 5.74 m/s^2. According to ISO 5349 for the daily vibration exposure expressed in terms of the 8-h energy-equivalent vibration total value, these values exceed the suggested exposure action value (EAV), but do not reach the exposure limit value (ELV). The maximal root mean square (RMS) vibration value is 3.79 m/s^2. According to the Enforcement Rules of the Labor Safety and Health Act No.302 from Council of Labor Affairs, daily allowable exposure duration can be longer than 4 hours, but can't exceed 8 hours. There is a positive relationship between engine speed and vibration. When the engine speed increases, the total vibration value increases as well. Furthermore, the selection of cutters has an influence on vibration. When a two-blade steel cutter is used on such machine, its vibration level is higher than that of the monofilament cutting device used on the same machine.