Design Of Hand Tools Research Articles

Psychometric Properties of the Persian Version of the Comfort Questionnaire for Hand tools (CQH)

Objectives: The comfort questionnaire for hand tools (CQH) is a subjective measure for exploring the starting points for improving hand tool design. This study aimed to investigate the psychometric properties of the Farsi version of the CQH.
 Methods: In this cross-sectional study, which was conducted among 163 university students, the 17-question CQH was translated into Farsi with a translation back-translation procedure. Content validity was assessed by a panel of 10 experts. Exploratory Factor Analysis (EFA) was applied for determining construct validity. Cronbach’s alpha and Intraclass Correlation Coefficient (ICC) were used for assessing internal consistency and test-retest reliability, respectively. Ceiling and floor effects were also estimated for evaluating the feasibility of the measure.
 Results: The CQH showed good content validity. Content validity index (CVI) ranged from 0.80 to 1.00 and Content Validity Ratio (CVR) ranged 0.62-1.00. EFA led to extraction of two factors from the data. The first one was mostly related to functionality and physical interaction and the second one, was generally about adverse body effects. The Cronbach’s alpha was 0.74 and test-retest reliability was 0.74 (95% CI = 0.58 to 0.86) which both were satisfactory. There were no (0%) ceiling and floor effects.
 Conclusion: The Farsi version of CQH is an acceptable and useful instrument for evaluating hand tools comfort.

Hand anthropometric survey of Iranian healthcare workers

AbstractBackgroundHand anthropometric data can help properly design hand tools and protective equipment for healthcare workers. This study aimed to measure and analyze the hand anthropometric data of Iranian healthcare workers.MethodsIn this cross‐sectional study, 33 hand dimensions were measured among 540 Iranian healthcare workers (270 male and 270 female) in six ethnic groups. Two‐dimensional imaging and traditional measurement methods were used. The data were classified and compared based on gender and ethnicity.ResultsThe results revealed a difference between the dimensions of males' and females' hands, which indicated that the dimensions of males' hands were larger. The results showed significant differences between different regions of Iran and other countries including the United States, Bangladesh, Nigeria, and Colombia.ConclusionDifferences in hand anthropometric dimensions should be considered in the design and manufacture of hand tools and hand protection equipment to prevent reduced productivity, occupational injuries, and diseases.

An investigation of the hand anthropometric database of agricultural workers and integration of the database into tools and protective gear designs.

The hand anthropometric data is the baseline for design of hand tools and equipment. This study aimed to generate the hand anthropometric database of male and female agricultural workers and compare it with the hand anthropometric data of other regions of India. The use of collected data is illustrated to design hand tools and protective gear. Hand anthropometric data were collected from 228 male and 198 female agricultural workers of northeast India. A total of 35 hand dimensions, stature and body mass from different tribes in the age group of 18-60 years were precisely measured. Measured data were statistically analysed to study the effects of gender, ethnicity, and age on hand dimensions. Correlation coefficients were determined among hand dimensions and linear regression equations were developed between highly correlated dimensions. The results show that all hand dimensions of the male and female subjects are significantly different (p < 0.01). Most of the hand dimensions were significantly different (p < 0.05) among different tribes for the male subjects. However, less number of hand dimensions were significantly different among tribes for the female subjects. Age of the subjects has significant effects (p < 0.01) on dimensions related to thickness, depth and circumference of fingers. The use of these data in the ergonomic design of hand tools and personal protective gear is illustrated to increase safety and comfort as well as efficiency of operators. There is a difference in the hand dimensions of different tribes of northeast India. This needs to be considered when designing agricultural hand tools and equipment.

Hand tool evaluation: a review of existing hand tool evaluation and selection studies

Hand tools were designed to increase workplace efficiency by improving work performance, preventing injuries, and increasing product quality. However, improper tool selection can cause costly losses and long-term decreases in productivity and safety. To prevent this, hand tool selection should be based on both engineering and ergonomics evaluations. This literature review provided a literature foundation for creating such hand tool selection method by reviewing over 100 hand tool research articles from 1945 to 2020 and categorised them into two categories: comprehensive hand tool evaluation systems and ergonomics hand tool evaluation studies. The literature from the two categories' research topics was summarised in two tables. Existing hand tool evaluation systems emphasised hand tool design and hazard outputs; ergonomics hand tool studies focused on users' feedback and user-tool performance. It became apparent that no comprehensive evaluation method reveals that no system can adequately provide buyers with sufficient information to make reasonable purchasing decisions. This literature review revealed the limitations of existing hand tool evaluation systems and ergonomics hand tool studies, presenting the future need for a financially-oriented, comprehensive hand tool evaluation system.

A Design Contribution to Ergonomic PC Mice Development.

Developing new manual computer pointing devices abiding to the requirements set out in ergonomic product design literature necessitates joining contributions from several areas, including the ergonomic guidelines applicable to hand tool design, human–system interaction, and certain user characteristics such as anthropometric data. Computer mice are hand tools enabling the interaction with the computer, for use by people from both sexes and practically all ages. Moreover, the PC mouse’s intensive usage is able to cause musculoskeletal disorders. This paper reports on a study aimed at developing new computer mouse shapes, reducing forearm pronation, and providing hand–palm holding, supported by a literature review and an adequate design methodology, starting from known shapes of commercial products, the traditional (horizontal) computer mouse, and the vertical computer mouse. In this regard, potential concepts were generated as solutions to the previously specified problem through a set of creative tasks based on the specifications. Four new shapes were proposed to be evaluated through an assessment matrix; as a result, two new PC mice geometries were designed and fully prototyped. This study also reports on selected results of usability and an electromyographic evaluation of the prototypes against three commercial PC mice (horizontal, slanted, and vertical) by a sample of 20 participants, supporting validation of the development process and the newly developed geometries, with emphasis on the slanted conical innovative shape.

How to implement inclusive design into distinctive feature hand tool? a design study on fine operation-aid screwdriver

Hand tool design should integrate the concept of Inclusive Design to be accessible to most users. However, current Inclusive Design strategies of product development are mostly used in post-design evaluation. The retention of inclusive properties in product when new functions are incorporated is essential. Fine operation-aid screwdrivers are designed according to user requirements to address frequently-encountered problems when using screwdrivers namely-insufficient lighting and difficulty in properly installing screws respectively. TRIZ method is applied, comprised the improving parameters solving the problems and worsening parameters which prevents the original inclusive design factors from being damaged into the contradiction matrix, and obtains a set of innovation principles. Eight experts were consulted for their design ideas and developed two fine operation-aid screwdrivers embracing the concept of Inclusive Design. Furthermore, factors regarding the two major operating problems were added to an existing hand tools Inclusive Design Scale. After correlation analysis, the inclusive fine operation-aid screwdriver evaluation scale was established. In addition, two more screwdrivers were selected with the same functions and high reviews on the market as control samples, and 39 users were recruited using a quota sampling strategy to participate in Inclusive Design evaluations. The results revealed that the fine operation-aid screwdrivers evidently solved the two major operating problems in terms of the five dimensions including functionality, comfort, professionality, safety, and usability in the inclusive fine operation-aid screwdriver evaluation scale, thereby affirming the rationality and reliability of our hand tool development approach.

Evaluation of the biodynamic response of the hand–arm system and hand-tool designs: a brief review

Hand-operated tools transmit a high magnitude of vibration exposure to the hand–arm system that causes occupational diseases. The health effects caused in various countries for the past years due to usage of hand tools are necessary to identify the occupational disorders. Researchers have conducted various studies on biological effects, hand-transmitted vibration exposure and biodynamic responses throughout the years. This article goes over each of these studies in detail, as well as identifying areas where more research is needed. The majority of studies deal with the following topics: general guidelines for hand-transmitted vibrations; assessment techniques of vibration exposure; hand-tool evaluation methods; influence of hand-tool design to overcome the biomechanical effects; and finite element modelling for quantifying vibration exposure. In response to this, understanding the biodynamic behaviour of the hand–arm system is useful for better ergonomic intervention in hand tools to reduce fatigue and increase comfort.

Hand anthropometry survey in Iranian adults and comparisons with other populations.

Hand anthropometry is useful for designing manual systems such as hand tools, controls, and gloves. There are limited published data on the hand dimensions of Iranian male and female adults. This study was undertaken to measure the hand anthropometric dimensions in Iranian adults to compare data between two genders and also with the corresponding data from other nationalities. A total of 34 dimensions of the right hand were measured in 217 male and 128 female adults using a digital caliper and tape. The mean, standard deviation, and the main percentiles are summarized in a table and the mean of each dimension is compared by independent t-tests between genders. Hand dimensions are compared between Iranian and other nationalities such as North Colombian, Korean, Turkish, Nigerian, Bangladeshi, Jordanian, and Vietnamese using the published data. Females had significantly smaller hand dimensions than males in all dimensions ranged from 4.21%to 18.16%, with the largest differences in hand breadths. Compared with other nationalities, the Iranian male and female adults had wider (greater breadth and circumferences) hands with shorter fingers. The results showed significant differences of hand anthropometry between Iranian and other nationalities which should be included in the design and selection of hand tools for Iranian population.

Financial Orientated Heuristic Evaluation for Hand Tools 2021 HFES International Annual Meeting

The goal of purchasing hand tools is to improve financial outcomes for buyers. These financialgains can come from multiple aspects of hand tools, such as increased productivity, improved product quality, and decreased injury rate. Based on a literature review, current hand tool purchasingdecisions are frequently made by professionals without specialized scientific backgrounds; however, the hand tool selection methods they receive are solely based on ergonomic evaluations. Heuristic evaluation, created by Nielsen &amp; Molich (1990), has been proven effective in discoveringusability issues quickly. Combined with the knowledge from hand tool evaluation literature andNielsen &amp; Molich’s (1990) heuristic evaluation platform, two versions of financially orientatedhand tool heuristic evaluations were created: a buyer version and a seller version. The buyer versionhelps hand tool buyers make financially orientated purchasing decisions; the designer version helpsquickly assess the financial viability of the hand tool design under review.

Effect of hand loads on upper extremity muscle activity during pushing and pulling motions

Manual pushing or pulling with a hand tool is a coordinated action by various upper extremity muscles. The objective of this experimental study was to examine the effects of horizontal and vertical hand loads on upper extremity muscle activity during concentric pushing and pulling exertions. Twenty young female participants conducted repetitive pushing and pulling trials with three horizontal loads (1 kg, 2 kg, 3 kg) and two vertical loads (0.6 kg, 1.3 kg) in a seated posture, while the myoelectric activity of seven upper extremity and shoulder muscles were quantified. Study results indicate that the shoulder flexor and extensor muscles were more strongly associated with horizontal load, and elbow flexors were more sensitive to vertical load. The empirical data from this systematic evaluation can offer initial insights for ergonomic design and evaluation of hand tools or occupational tasks that involve repetitive pushing or pulling.

Effects of handle characteristics of manual hand tools on maximal torque exertions: a literature review

The present study was conducted to review the literature on the effects of handle characteristics of manual hand tools including handle diameter, shape and material on forearm supination/pronation, wrist flexion/extension and wrist ulnar/radial deviation torque strengths to assist ergonomists and designers in developing guidelines to improve workstations and hand tool designs. Twenty-seven papers meeting the inclusion criteria were reviewed. The study provides different points that can be applied to improve the design of hand tools with an emphasis on handle diameter, shape and material, and highlights various methodological issues including interactions among variables affecting maximum torque strength, posture, torque exertion using one or two hands, torque exertions in multiple anatomical axes, using gloves, upper extremity anthropometry and test protocols, which should be considered in future research.

The Hand-Tool Design Ergonomics Principles in Handicraft Workplaces: A Hybrid Approach of Ergonomics and Participatory Design

The Hand-Tool Design Ergonomics Principles in Handicraft Workplaces: A Hybrid Approach of Ergonomics and Participatory Design

Improving ergonomics in the operating room for orthopaedic surgeons in order to reduce work-related musculoskeletal injuries

IntroductionOrthopaedic surgery is characterized by surgical tasks that are physical, repetitive and require some degree of stamina from the surgeon. Occupational injuries are alarmingly common in orthopaedic surgery with two-thirds of all surgeons reporting a work-related musculoskeletal (MSK) injury during their career. One of the leading causes of the high level of MSK injuries among orthopaedic surgeon is lack of ergonomics of the operating room. Implementing an ergonomic process has been shown to be effective in reducing the risk of developing MSK disorders in other high-risk industries. We reviewed well-established and effective ergonomic guidelines from the industrial workplace and determined the pertinent principles that could be transferred to the operating room to help reduce the number and severity of common orthopaedic work-related MSK injuries. MethodsWe reviewed the ergonomic guidelines, primarily from the Occupational Safety and Health Administration (OSHA), that specifically address minimizing the risk of these work-related injuries and that are transferable to the operating room. In addition, the ergonomic guidelines from the Canadian Center for Occupational Health and Safety (CCOHS), the National Institute for Occupational Safety and Health (NIOSH) and the Centers for Disease Control and Prevention (CDC) were reviewed. ResultsMany of the guidelines to avoid work-related injuries in industry are transferable to the operating room. The pertinent guidelines clearly indicated how to adjust the height of the operating table, the proper design of hand and power tools and the modifications to the operating room environment that can help prevent injury. These guidelines from industry include maintaining a neutral posture and joint alignment, working with the appropriate hand tools and minimizing the lower extremity fatigue by using the proper footwear and floor mats. DiscussionOptimizing the occupational environment and utilizing well-established ergonomic principle from industry is both feasible and practical in the operating room to decrease the incidence of musculoskeletal injuries among this high-risk profession. These guidelines are simple, effective and are easy to implement by orthopaedic surgeons in order to minimize their risk of sustaining a work-related injury.

A survey of hand anthropometry of Bangladeshi agricultural farm workers

The target of this investigation was to represent an anthropometric dataset of hand dimensions from agricultural farm workers in two different areas of Bangladesh. A total of 200 farm workers (110 males and 90 females) age between 15 and 52 years-old were included as voluntary participants from two regions of Bangladesh. 27 hand dimensions were measured, recorded, and analysed from the sample populations. The mean, standard deviation, and different percentile esteems of collected data were also estimated and recorded. Moreover, Kolmogorov-Smirnov and t-statistical tests were performed for making the anthropometric comparison among different populaces. Results showed that all the hand dimensions of the males were higher than that recorded for the female participants of Bangladesh. In addition, the outcomes showed noteworthy contrasts in hand measurements among Bangladeshi people and other considered populaces. The result of this examination is expected to influence the design of agricultural hand tools, machinery, and equipment in Bangladesh from industrialized countries. It will also generate the interest of more anthropometric studies in Bangladesh that are related to the design of hand tools or equipment for work or other activities.

Ergonomic assessment of a new hand tool design for laparoscopic surgery based on surgeons’ muscular activity

Laparoscopic surgery techniques are customarily used in non-invasive procedures. That said traditional surgical instruments and devices used by surgeons suffer from certain ergonomic deficiencies that may lead to physical complaints in upper limbs and back and general discomfort that may, in turn, affect the surgeon’s skills during surgery. A novel design of the laparoscopic gripper handle is presented and compared with one of the most used instruments in this field in an attempt to overcome this problem. The assessment of the ergonomic feature of the novel design was performed by using time–frequency analysis of the surface electromyography (sEMG) signal during dynamic activities. Singular Spectrum Analysis (SSA) was used to decompose the sEMG signal and extract the median frequency of each muscle to assess muscle fatigue. The results reveal that using the proposed ergonomic grip reduces the mean values of the muscle activity during each of the proposed tasks. The novel design also improves the ease of use in laparoscopic surgery as it minimises high-pressure contact areas, reduces large amplitude movements and promotes a neutral position of the hand, wrist and forearm. Furthermore, the SSA method for time–frequency analysis provides a powerful tool to analyse a prescribed activity in ergonomic terms. The proposed methodology to assess muscle activity during surgery activities may be useful in the selection of surgical instruments when programming extended procedures, as it provides an additional selection criterion based on the surgeon’s biomechanics and the proposed activity.

Development and testing of a wearable wrist-to-forearm posture measurement system for hand-tool design evaluation

This study reports on the development and testing of a wearable wrist-to-forearm angle-measurement system for flexion/extension and radial/ulnar deviation of the wrist, and pronation/supination of the forearm. The system is based on inertial sensors and a microcontroller mounted on a glove and a forearm pad. The developed system was tested through the comparison of two off-the-shelf screwdrivers, one long and one short. Twelve male subjects participated in a within-subject experimental design test and performed a horizontal and a vertical screwing task for each screwdriver. Results indicated that the use of a long screwdriver causes significantly higher ulnar deviation of the wrist in both set-ups, while the short screwdriver promotes higher wrist extension in both set-ups. Clarity of the obtained results indicates that the proposed system is adequate for ergonomics studies on hand-tool design evaluation, while it addresses common pitfalls of other motion-capture methods.

The effect of hand tools’ handle shape on upper extremity comfort and postural discomfort among hand-woven shoemaking workers

Hand tools are widely used in a large number of occupations. Many workers have to use hand tools to accomplish their duties. This may cause work-related Upper Extremities Musculoskeletal Disorders (UEMSDs). The present study was conducted in Iranian hand-woven shoe industry to (a) investigate the design of hand tools currently used in hand-woven shoemaking operation and (b) design/redesign the tools' handles based on anthropometric tables and ergonomic principles. Based on Iranian workers' anthropometric tables, new handles with different shapes were designed and made for hand tools currently used in hand-woven shoemaking operation (e.g., awl and cloth cutting tool). Hand postures and postural comfort and discomfort were investigated via rating technique using Comfort Questionnaire for Hand Tools (CQH) and upper extremities body map. The results of CQH showed that the handle shape had a significant influence on the hand posture and perceived postural discomfort in the upper extremities. The new ergonomically designed handles were perceived to be more comfortable compared to the traditional ones. Additionally, the new handles improved the hand posture during the operation and reduced the severity of discomfort in the upper extremities compared to the tools with conventional handles. The findings of this study revealed that designing the hand tools’ handles based on ergonomic principles and using anthropometric tables could improve the hand posture, increase comfort, and decrease discomfort in the upper extremities. By this means, reduction in work-related UEMSDs is expected.

The Influence of Hand Tool Design on Hand Grip Strength: A Review

Hand is made up of bones, tendons, ligaments, nerves and blood vessels that can be easily debilitated and injured if the hand tool is not design ergonomically. Recently researchers have examined the effects of individual, environmental and occupational factors on hand grip strength. However, information on the influence of hand tool design on hand grip strength is still lacking. The aim of this paper is to provide a comprehensive review of factors influencing hand grip strength focusing more towards hand tool design factors. The authors searched the journal articles, book and guidelines from the online databases of Google Scholar, ScienceDirect and Pubmed. Fourteen factors of hand tools design were found to have significant effect on the hand grip strength. The handle size shows the most significant factor for hand grip strength.

Ergonomic design and evaluation of masons' trowels for construction work

This study investigated the effects of five redesigned masons' trowels (with handles with variable cross-section that provided different patterns of grip) and hand anthropometry on muscle activity, usability and affordance in a working context, and the results were compared with that of the traditional design with longitudinal round cross-sectional handle. The results showed some improvements in terms of usability and affordance with the second prototype design. Usability was also improved with the first prototype trowel design, although it required higher electromyographic activity levels compared to some other designs. Hand anthropometric measures had no effect on the studied measures. The results suggest that although improving performance and usability may not necessarily be compatible objectives, the idea of cylindrical tool handles with variable cross-section can be employed advantageously to improve the tool's usability. The findings may also rule out the possibility that users' hand anthropometry is always necessary for the design of tool handle. Rather, hand tool designers and manufacturers should pay special attention to the working context and quality of hand-handle interaction to improve the design and usability of hand tools.

Gender considerations in optimizing usability design of hand-tool by testing hand stress using sEMG signal analysis

To design comfortable and efficienthand tools, an objective measurement such as using surface electromyography (sEMG) is required, where the ergonomic design tries to find the most optimal and most fit design of hand-tool that doesn't cause stress on the hand muscles. The hand tool design optimization will be demonstrated in this study on designing shampoo bottles, where the design of bottle and its compatibility with the slippery watery area, in addition to the aesthetic considerations are important issues that must be taking by the manufacturers concerned with such industries. Six different designs of shampoo bottles, as outcomes of industrial design graduation project in the department of Industrial design at our university, were used in this study. The new designs, together with other traditionally bottle designs, were evaluated in simulated shampoo pouring task in the laboratory. Several important parameters extracted from the sEMG signal in both temporal domain and frequency domain provide useful information about the tested designs. Twenty healthy university students (10 males and 10 females; mean age of 21 ± 2 years) were included in this study. Each subject was asked to handle the bottle and simulate the shampoo pouring activity in gentle and delicate manner using the grasp pattern that is found most comfort for him/her. Muscular behavior during bottle holding and shampoo pouring tasks show that male and female have different preferences in dealing with different bottle design, where male have less hand stress with designs that achieve the best fit of their full hand, while female have less hand stress with designs that achieve the best fit of their fingertips, and therefore, the end-user gender must be considered in designs of such industries.