بررسی برخی مداخلات ارگونومیکی در عملیات دسترسی به تاج نخل خرما

با وجود اهمیت و جایگاه خرما در کشور و جهان، تولید خرما به ویژه عملیات دسترسی به تاج نخل خرما به عنوان گسترده‌ترین و دشوارترین عملیات تولید خرما، به صورت سنتی و همراه با مخاطرات ارگونومیکی و ایمنی متعددی انجام می‌شود. در مطالعه حاضر، برخی مداخلات ارگونومیکی با سازوکار غیرپیچیده در عملیات دسترسی به تاج نخل خرما با به کارگیری 9 شرکت‌کننده با هدف کاهش مخاطرات بررسی و از حیث شاخص‌های ارگونومیکی، ایمنی و فنی با روش مرسوم مقایسه شد. ارزیابی‌های بیومکانیکی با استفاده از نرم‌افزار 3dsspp و بررسی تنش‌های مکانیکی وارد بر ابزار صورت گرفت. تجزیه و تحلیل‌های آماری با استفاده از نرم‌افزار ibm spss 24 انجام شد. ارزیابی‌های بیومکانیکی نشان داد که از بین چهار روش مورد بررسی صعود از نخل خرما (مرسوم (استفاده از پروند) و مداخله‌ای (پروند+کفش لاستیکی، هارنس و هارنس+کفش لاستیکی))، روش‌های مرسوم و پروند+کفش لاستیکی به ترتیب با وارد آوردن نیروهای برشی 1120.9 و 1119.6 نیوتون بر دیسک l5/s1 از این منظر از دو روش دیگر که در آن‌ها از هارنس استفاده می‌شد به طور معنی‌داری (0.001>p ) پرخطرتر و دارای ریسک ابتلا به آسیب زیاد (500 نیوتون ) بودند. روش هارنس+کفش لاستیکی به لحاظ ارجحیت بالاترین میزان (14 امتیاز) را به خود اختصاص داد. ابزار‌های مداخله‌ای به لحاظ ایمنی وضعیت به نسبت مطلوب‌تری از روش مرسوم داشت، اما به لحاظ ارگونومیکی شرایط تقریباً برابر بود. با این وجود، ابزارهای مداخله‌ای به لحاظ سرعت کار و شرایط فنی دارای کاستی‌هایی بود که باید تا رسیدن به شرایط مطلوب مورد مطالعه و بهسازی قرار گیرد.

investigation of some ergonomic interventions in date palm crown access operation

introduction date fruit production has an important position in either iran or the world. life and economy of many of people who live in the west asia and north africa (wana) depend on this agricultural product. date palm crown access, as one of important operations of date fruit production, is performed in a traditional manner with a tool talked “parvand” yet. it results in various ergonomic and safety problems, such as fall from height, sunstroke, and musculoskeletal disorders (msds). meanwhile, mechanization could not adequately adopted by date palm growers. possibly, ergonomic interventions in forms of simple tools mitigate ergonomic and safety problems in date palm crown access operation.materials and methods in this study, some ergonomic interventions were investigated to improve the present status of ergonomic and safety status of this operation with employing nine workers from ramshir city, khuzestan province, iran. evaluated date palm climbing tools were as follows: parvand (traditional tool), parvand+rubber shoes (intervened tool), harness (intervened tool), and harness+rubber shoes (intervened tool). parvand consisted of a backrest and a towing wire. in two last mentioned intervened tools, harness was replaced with backrest in parvand. indeed, harness was the brief name of composition of harness and towing wire. comparisons were done based on some ergonomic, safety, bio-mechanical, and technical indices. ergonomic evaluations included physical and cognitive ones. body discomfort (bd), heart rate (hr), worker energy expenditure (ee), working oral temperature (ot), and physiological strain index (psi) were the physical indices. perception-based heat strain index (pesi) and acceptance of climbing tools in view of workers were the cognitive indices. acceptance comprised workers’ perception about safety, work speed, ease of use, technical properties, and preference of the tools. safety evaluation was conducted using failure mode and effects analysis (fmea) which resulted in a risk priority number (rpn) for each climbing tools. bio-mechanical evaluations were performed using 3dsspp software (to find the compression and shear forces on l5/s1 disc) and the investigation of mechanical stresses of parvand and harness (to achieve the factor of safety (fos) of tools). technical index was the total time cycle (ttc) to perform date palm crown access (install climbing tool, ascending, and descending). statistical analysis was conducted using ibm spss 24. during evaluation, workers’ qualitative feedbacks around intervened tools were recorded.results and discussion mean age, height, mass and body mass index of workers were 33.1 years, 1.71 m, 74.0 kg, and 25.3 kg/m2, respectively. according to the statistical analyses, there was no any significant difference among climbing tools regarding bd, hr, ee, ot, psi, pesi, rpn, and ttc. bio-mechanical evaluations showed that all four climbing tool caused a low risk compression force on l5/s1 (<3400), whereas interventions including harness were significantly higher than those including parvand. traditional and parvand+rubber shoes with shear forces of 1120.9 and 1119.6 n, respectively, on l5/s1 disk resulted in high injury risk (>500 n) and were significantly higher than other two methods in which harness was used (p<0.001). fos was achieved for parvand and harness 1.21 and 3.53, respectively.