Ergonomic Bench to Decrease Postural Risk Level on the Task of Changing Forklift's Brake Pads: A Design Approach

Introduction

Most of the ergonomic assessment methodologies adopted in the manufacturing industry are implemented to assess ergonomic hazards in the production area (Tompa, Dolinschi, de Oliveira, Amick, & Irvin, 2010), yet other processes, such as machinery maintenance/repairs, material transportation, and/or plant cleaning, require similar ergonomic evaluations to ensure employee safety. To address this gap, this research takes place in a company that repairs and sells industrial machinery.

It is well known that maintenance and repairing tasks force employees to adopt awkward postures (Barros, Marçal, & Soares, 2015; Teymourian, Seneviratne, & Galar, 2016) and apply excessive force. In this sense, the maintenance technicians of the company wherein this study was conducted have claimed to experience discomfort when they change forklift brake pads. This task takes approximately one hour per brake, and to complete it, the technicians usually adopt awkward and long-lasting postures. According to the employees, the main musculoskeletal complaints experienced are in the back, the ankles, and the knees. Even though knee pads are worn, the employees claim these are not an effective solution to pain and discomfort. Figure 1 depicts the typical posture adopted by the employees as they change forklift brake pads.

According to the literature, awkward postures have a negative effect on employee health and performance. They can cause soft tissue injuries that favor the accumulation of metabolites and accelerate disc degeneration, which can ultimately lead to disc herniation (Roffey, Wai, Bishop, Kwon, & Dagenais, 2010). Also, awkward workplace postures can increase the risk of suffering from musculoskeletal disorders (MSDs) – such as osteoarthritis (da Costa & Ramos-Vieira, 2009; Gallagher, Pollard, & Porter, 2011) and fibromyalgia (da Costa & Ramos-Vieira, 2009) – and are strongly associated with low back pain (LBP) and whole-body vibration (Vandergrift, Gold, Hanlon, & Punnett, 2012).

As regards employee performance, awkward postures are less efficient than postures that keep joints near to a neutral posture (Gangopadhyay, Ghosh, Das, Ghoshal, & Das, 2010). Also, it has been argued that awkward postures force employees to apply more force than necessary to accomplish a particular task. Such excessive force in turn affects muscle loading and compressive forces on the internal vertebral disc.

Figure 1.

Posture adopted by employees during the task of changing forklift’s brake pads

Source: Prepared by the authors (2017).

The literature shows the need to improve the working conditions of those who adopt awkward and unsuitable postures to do their jobs. In the context of our research, one alternative to addressing this need is to design a bench, as an ergonomic work tool, to ensure that the technicians can change the brakes safely and comfortably. The importance of this bench relies on its advantages as an ergonomic intervention. Ergonomic interventions do not only reduce workplace hazards and increase employee safety; from a corporate point of view, they provide economic benefits, since they prevent companies from incurring additional costs (e.g. employee insurance) and increase employee retention, since workers feel and are safe.