Ergonomic Design of an Aerial Bucket for Ingress and Egress
Electric utility companies across the US have been using aerial bucket trucks for line work and troubleshooting for decades. The use of these trucks eliminates the need for workers to climb utility poles in order to repair or maintain lines. Poor ingress and egress design can lead to acute injuries (slips and falls) as well as cumulative injury (musculoskeletal disorders (MSDs)). Utility companies want to know the best combination of steps and handlebars for aerial bucket ingress and egress that would minimize the risk of injury. American National Standards Institute (ANSI) standard – ANSI/SIA A92.2-2009, sets design requirements for aerial buckets that provide regulations for factors of safety. Based on the testing procedures for electrical ratings (which can exceed 100kV for electric line work), an access door to an aerial bucket is not feasible at this time for most electric utilities. The objective of this research was to test whether bucket design features for a one-person bucket offer ergonomic advantages to workers for ingress and egress. Muscular activity of the four most affected muscle groups in the upper and lower extremities were analyzed using EMG sensors throughout ingress and egress. A series of conditions that integrated variations of the design features (inside step, outside steps and a horizontal handle bar) were tested. Based on results, the following design recommendations would decrease the risk of a slip or fall and the biomechanical loading to the upper extremities when entering and exiting the bucket: 1. Always have an inside step – on either the front side (side with the outer steps) or in an adjacent corner location. 2. Have one outside step, with a horizontal handlebar on the boom side of bucket for support. 3. If a bucket has two outer steps, then a horizontal handlebar must be mounted on the boom side of bucket.