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29 ReferencesThe effects of box size, frequency and extended horizontal reach on maximum acceptable weights of lifting
Abstract
In the development of our present manual materials handling (MMH) guidelines (Ergonomics 34 (1991) 1197), the assumption was made that the effects of frequency on maximum acceptable weights (MAWs) of lifting with a large box (hand distance, 38 cm from chest) were similar to frequency effects on MAWs of lifting with a small box (hand distance, 17 cm from chest). The first purpose of the present experiment was to investigate this assumption. The second purpose was to study the effects of extended horizontal reach lifting (hand distance, 48 cm from chest) on MAWs as a confirmation of the results of a previous study on this variable. Lastly, we studied the effects of high frequency (20 lifts/min) on MAWs of lifting. Eight male industrial workers performed 15 variations of lifting using our psychophysical methodology. As expected, the results revealed that MAWs of lifting with the large box was significantly effected by frequency. Frequency factors based on the 1 lift/min task illustrated less change to higher frequencies (>1 lift/min) and more change to slower frequencies (<1 lift/min) as compared to lifting with the small box. It was concluded that our existing guidelines present a conservative estimate of lifting large boxes in the spectrum of frequencies studied. The results also verified the extreme effects of lifting with an extended horizontal reach and quantified the effects of the 20 lifts/min lifting frequency.Relevance to industry:Lifting is the most common MMH task but certain variables such as large containers and extended hand distance have been given considerably less attention in research. This study investigated these select variables of lifting in an effort to improve estimation of MAWs for ergonomic redesign.
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- Moreover, Neumann and Medbo (2010) compare the picking of components from small containers to that from EUR-pallets with collars and find that picking time as well as physical workload of the operator, in terms of both peak load and cumulative load, is reduced when small containers are used. Similarly, Ciriello (2003Ciriello ( , 2007) find that the maximum acceptable weight is dramatically reduced with extended horizontal reach, i.e. with an increased horizontal distance between the picker and the object lifted. Finnsgård and Wänström (2013) present a full factorial experiment, studying how picking time is affected by part size, packaging type, and different aspects of how the components are presented.
[Show abstract] [Hide abstract] ABSTRACT: Picking of components from large containers is common both within trade and industry, but is often associated with poor working conditions in terms of ergonomics, as well as with low time efficiency. Providing quantitative evidence from an actual industrial setting, the paper shows how both the picking time and the physical workload varies depending on the position of each component within the container picked from. It is clear that there are considerable differences between the front and the rear sections of the pallet, as well as between the top and the bottom sections. Moreover, the paper shows that picking from a large container that is tilted is significantly better from a perspective of time efficiency. In contrast, the difference in terms of physical workload between picking from a horizontal and a tilted pallet is relatively small for most pallet sections.- Troyes, France operators. Thus, Ciriello (2003) considers the effects of box size, frequency of pick and the required horizontal extension on the maximum acceptable weights of lifting. Neumann and Medbo (2010) compare two alternative supply system strategies, big boxes and narrow bins.
[Show abstract] [Hide abstract] ABSTRACT: Assembly Line Balancing Problems (ALBPs) describe a partition of tasks into subsets, each subset forming a station load, to optimize some line efficiency measure under specific task-to-station assignment restrictions. In the literature, the assembly line balancing problem is usually solved separately from the assembly parts feeding problem, which is to determine a supply mode for each part associated with assembly tasks. This leaves significant optimization potential untapped. In this work, we consider the problems jointly and set up the Integrated Assembly Line Balancing and parts Feeding Problem (IALBFP). In the formulated IALBFP, we distinguish between two alternative parts supply modes: direct parts feeding in homogeneous load units (big boxes) and indirect lean parts feeding, where parts are supplied in station kits to each station at the beginning of each cycle after some intermediate handing at the supermarket area. In this way, the indirect parts feeding is fully synchronized with operations at the assembly line. We also incorporate ergonomic aspects by increasing processing times of manual tasks by a time increment to recover from fatigue and energy losses. We formulate a mixed-integer model for IALBP and provide guidelines for the implementation of our integrated planning approach in practice. To our best knowledge, we are the first in the literature to model a lean parts feeding system, which is fully synchronized with assembly line operations. Incorporating ergonomic aspects into IALBFP allows to design a satisfactory assembly system in terms of both ergonomics and productivity and is a further novelty of this work. The implementation of the proposed integrated approach in practice may significantly reduce inventories at the line where space is notoriously scarce, minimize time losses due to unproductive activities and lower fatigue of workers.- One example is a change in the packaging of items to improve ergonomic handling, for example, by using boxes with handles (Davis and Marras 2000). When integrating the goal of minimising worker health risks besides short travel time in an OP planning model, researchers could refer to findings from the ergonomic literature on maximum acceptable lift weights and heights (Straker, Stevenson, and Twomey 1996; Ciriello 2003), which could lead to new storage assignment policies. In addition, future research could develop models on investments in training to enable experienced workers execute pick tasks faster, which may help to improve system performance and worker welfare.
[Show abstract] [Hide abstract] ABSTRACT: Order picking (OP) activities, essential to logistics operations, are laborious and time-intensive. Humans are central actors in the OP process and determine both OP effectiveness and efficiency. Many researchers have developed models for planning OP activities and increasing the efficiencies of such systems by suggesting different warehouse layouts, OP routes or storage assignments. These studies have, however, ignored workers’ characteristics, or human factors, suggesting that they cannot be substantiated, which led to only partially realistic results. This paper proposes a conceptual framework for integrating human factors into planning models of OP activities and hypothesises that doing so improves the performance of an OP system and workers’ welfare. The framework is based on a systematic literature review that synthesises findings documented in the OP and human factors literature. The results of the paper may assist researchers and practitioners in designing OP systems by developing planning models that help in enhancing performance and reducing long-term costs caused by work-related inefficiencies.- This could be due to a long handle of the ladle, heat stress because of hot melted materials, attention in pouring the melted materials into the cylinder, high repetition of the task during the shift and the horizontal shift away from the body. The present study revealed that a decrease in weight affected horizontal distance more than a decrease in height, which is in step with Ciriello's results [24]. The weights in 66% of the carrying tasks exceeded acceptable weights (Table 4).
[Show abstract] [Hide abstract] ABSTRACT: Manual material handling (MMH) tasks can be found in most workplaces and they may constitute a risk factor for work-related musculoskeletal disorders (WMSDs). This study was conducted to determine the prevalence of WMSDs and to compare MMH loads with the acceptable weight and force limits among Iranian casting workers. Data were collected from 50 workers of casting workshops who performed MMH tasks. The Nordic musculoskeletal disorders questionnaire and the Snook tables were used as tools for data collection. Hand/wrist symptoms were the most prevalent problems among the workers (84%). The results of the Snook tables showed that the loads in lifting (84%), lowering (86%), carrying (66%), pushing with initial (43%) and sustained force (59%), and pulling tasks with initial (48%) and sustained force (93%) exceeded recommended limits. WMSDs occurred in high rates among the workers and, thus, ergonomics interventions should focus on decreasing WMSDs and redesigning MMH tasks.- When gripping a small object, the finger flexion creates folds in the skin and results in a reduced contact with the object (Seo and Armstrong 2008). In lifting research, the size of an object may affect the maximum acceptable weight of load, maximum acceptable weights of lifting, energy expenditure and spinal stresses (Ayoub and Mital 1989, Ciriello 2003, Jung and Jung 2010). Also, the size of tool handles often has a substantial effect on the biomechanical, physiological and perceived stress of the worker (Jung and Jung 2010).
[Show abstract] [Hide abstract] ABSTRACT: In handgrip-related studies, it has been theorised that modifying the design of object shapes and sizes to accommodate the hand can reduce risks of cumulative trauma disorders (CTDs). However, there appears to be a lack of theoretical groundwork to support this premise in the area of pinch grip research. Therefore, this article aims to provide a review of shape and size considerations in pinch grips. The literature reviews were first conducted individually on shape, size and pinch grip factors, followed by the development of a literature summary based on the theoretical connections among shape, size and pinch grips. Though further studies are still required, this review has provided fundamental knowledge on possible theoretical connections among shape, size and pinch grip factors. These preliminary efforts shed light on potential mechanisms that explain how shape and size can influence pinch grips towards preventing CTDs and maximising the human performance.- There are not any standards or requirements which describe suitability tests related to this. But the stresses can be defined by the well-known test parameters (from other packaging tests) and considering the parameters of packaging (material and weight of packaging, the parameters of the manual handler, etc.) [7][8]. The main aspects during the industrial development and design of packaging with carrying handles – like for multipacks – are the ergonomic and minimization principles [9][10][11].
[Show abstract] [Hide abstract] ABSTRACT: Carrying handles of packagings have a great importance in the comfortable and safe handling of packed products. Producers and consumers have to face occasionally damaged carrying handles that considerably increase the possibility of the damage of the product. These carrying handles are of a wide variety, depending on the package size, packaging material, weight, etc. The main reason for frequent product damages is due to the fact that producers lack the sufficient knowledge of stresses. In this paper we analyze the stresses and propose a measurement process for packaging with a carrying handle. We measure the stresses via a range of standard equipment (cameras, accelerometers, shaker table). In addition, we provide a general framework and the description of a test environment for the accurate reproduction of the logistic stresses appearing in packaging with a carrying handle.
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