Ergonomics & Vibration in Powered Hand Tools Used in Meat Processing

Abstract

The purpose of this study was to determine the triaxial acceleration levels of a group of powered circular knives extensively used in the meat processing industry. These tools were tested in real time under actual work conditions while the operators used the tools in 23 different applications. The length of the study was 11 months, encompassing 685 tools, at 13 plant sites using 5 different diameters of circular tools. All vibration tool measurements were recorded from three triaxially mounted individually calibrated, PCB accelerometers. Customized software programs allowed a Gateway 2000 SOLO computer to cycle, collect, and record vibration data for a minimum of a one minute time frame. The study results showed that neither the ANSI S3.34 nor the ACGIH hand-arm vibration standards were exceeded for an 8–hour workday. The median acceleration levels for the five different sized diameter tools did not significantly differ. The operating levels increased only slightly from a new tool that has been determined to be operating at maximum efficiency. Examining the different tool applications, operators, plant locations and tool conditions resulted in concluding that for this type of tool the most important factor contributing to the acceleration intensity levels was tool maintenance and the conditions of its parts. Tools with higher vibration acceleration levels were disassembled and found to have at least one part severely worn or damaged. After the part(s) were replaced, the tool was re-tested under the same work conditions, the vibration acceleration levels on average decreased by 16%. As part of an overall effort, operator exposure to vibration generated by these powered circular knives can be significantly reduced and controlled by proper tool care and maintenance.