Showing 7 results for Tools
Mohammad Sadegh Sohrabi,
Volume 3, Issue 2 (9-2015)
Abstract
Introduction: The weak design of hand
tools and their disharmony with the user's physical features comprise a major
risk factor for upper limb musculoskeletal disorders. Hand-tool related
injuries comprise almost 9% of all work-related injuries. The present study was
conducted to examine the effect of hand tools' diameter on comfort and maximum
hand torque and to estimate the optimal diameter for hand tools.
Methods: Participants included
6 men and 6 women with a mean age of 24.7 and a standard deviation of age of
5.84 years. Participants started to load and rotate the grip of 7 hand tools
with different diameters with all their power and using a self-made tool for measuring
the torque. The test duration, maximum torque and comfort level of the tool
grip was then measured and the data obtained were analyzed using the ANOVA and
the t-test.
Findings: The mean maximum
torque value obtained was 1.88 (SD=0.95) newton meter, the time taken to reach
the maximum torque was 13.96 (SD=9.03) seconds and the mean comfort level was
3.27 (SD=1.48) at a scale from 1 to 7. There was a significant difference
between the maximum torque generated in the group of men and the group of women
(p<0.001). The mean maximum torque obtained was 3.034 newton meter and the
mean maximum comfort level was 4.67, achieved with a grip diameter of 38 mm.
Conclusion: The optimal hand tool
diameter recommended for maximum user comfort and torque is 38 mm.
Soudabeh Asadollahi, Iman Dianat, Moein Nedaei,
Volume 5, Issue 2 (9-2017)
Abstract
Introduction: Scissors are essential tools in different occupations including sewing and clothes making. Improper design of fabric cutting scissors can lead to the development of musculoskeletal symptoms among users. The aim of this study was to evaluate pinch force and wrist posture while working with three designs of sewing scissors and a traditional sewing scissors.
Methods: The first model of the scissor had a bent-handle (to improve wrist posture), the second model had a thumb-ring that was located closer to the pivot (to reduce thumb’s abducted position and range of movement), and the original oval ring in the third model was changed to a hook-shaped handle (to reduce hand and finger discomfort). Pinch force was measured using a pinch gauge and wrist posture was measured in two anatomical planes including flexion/extension and ulnar/radial deviation using the observational method.
Results: The results showed significant effects of scissors' design on pinch force exertions (P < 0.01) and ulnar/radial deviation of the wrist (P < 0.001). The lowest level of pinch force decrement between pre- and post-pinch force measurements was recorded for the second model (2.4%), while the highest level was recorded for the traditional model (7%). More neutral wrist postures in ulnar/radial direction (83%) were recorded for the first model compared to the other designs.
Conclusions: The second scissors, which was designed to reduce thumb’s range of motion and abduction, showed some improvement in pinch force compared to the traditional model.
Dr Rashid Heidarimoghadam, Dr Mohammad Babamiri, Dr Majid Motamedzade, Nasrin Nouri,
Volume 5, Issue 3 (11-2017)
Abstract
Background: The design of tools may play an important role in development of the problems related to hands and arms. The health and satisfaction of those who use these tools can be affected by the improvement of ergonomic tools. This research aims to assess the local discomfort caused by the usage of common pencils comparing to the ergonomic ones.
Methods: 50 right-handed students (girls only) participated in this study. They wrote one paragraph using all the writing tools that were being studied in this research. At the end the comments were collected using the LPD questionnaire and were analyzed by t-test and Mann-Whitney test and SPSS version 23.
Results: The results of the CHQ questionnaire showed that this questionnaire could be a useful tool for assessing the comfort of using writing tools among students in the school environment. Also, the results from the LPD scale showed that this scale could be very helpful for assessing local perceived discomfort among school students. In the second part, the results of the comparison of the mean of data from the CHQ questionnaire and the LPD scale showed that there is a significant difference between the common pencils and the designed pencil for comfort and local perceived discomfort.
Conclusion: It was found that common pencils cause pain, pressure, inflammation and numbness in the hands and forearm and shoulder. And the use of designed ergonomic pencil will reduce the pressure and pain on the hands and shoulders.
Mahboubeh Sadat Rahmanpour, Abbas Ebadi, Aram Tirgar,
Volume 6, Issue 3 (10-2018)
Abstract
Background and Objectives: The objective of hospital accreditation is to increase the safety and satisfaction of patients and employees, with the contribution of which can be achieved through environmental adaption. The present study aimed to explain the necessity of using ergonomic considerations in the process of hospital accreditation.
Methods: This methodological study was designed in 2018 and simultaneously conducted with the psychometric evaluation and validation of the structural fitness assessment tool of age-friendly hospitals. The determination of the structural components was done by examining the texts and validating the items using the Delphi method. After determining the content validity, classification of items into mandatory or essential sections was made by obtaining at least two thirds and one thirds of the experts votes, respectively. Descriptive and inferential statistics were used for data processing.
Results: The processing of expert opinion about 72 items (content validity) showed that the majority of subjects (55 items equivalent to 76%) were mandatory or essential, with the highest proportion of mandatory cases being made by the gerontologists, and the least architectural experts.
Conclusion: Considering the growth of the elderly population in the country and, on the other hand, the high contribution of the elderly to the treatment centers, and the necessity or basicity of the majority of tool items, the application of ergonomic principles in the accreditations seems necessary.
Mahnaz Ahmadlu, Mostafa Pouyakian, Mohammad Ranjbarian, Soheila Khodakarim,
Volume 7, Issue 2 (9-2019)
Abstract
Background and Objectives: There are various models of socket wrench in the market varying in the length and diameter of handle and weight. Each of these features alone can modify the force applied by the hand and affect how comfortable the user is. The purpose of this study was to investigate the relationship between dimensional properties and weight of several models of socket wrench with their usability index score.
Methods: 58 male technicians from maintenance units of Shahid Beheshti University of Medical Sciences performed the task of opening 12 bolts with 8 N/m of torque using 6 models of socket wrench with different physical properties. The sample size was selected based on proposed figures for usability studies. The System Usability Index (SUS) validated questionnaire was used to determine the usability score of each model after the experiment. The study was conducted in 2017. SPSS 21 was used for data analysis.
Results: The results showed that there was a significant relationship between usability index score and dimensional properties and weight of wrenches (P<0.001). Wrench models with longer handle and diameter size close to optimum range of diameter of hand tools for male users had a higher usability score, and participants reported a better test experience with these models.
Conclusion: Using the System Usability Index (SUS Questionnaire) to measure the quality of human-centered design of hand tools is a good way to evaluate and select the hand tools that are widely used by technical staff. The results of this study are valid for short-term applications of wrenches. However, for long time activities, epidemiological and physiological evidences such as EMG should also be used.
Azam Maleki-Ghahfarokhi, Iman Dianat, Mohammad Asghari Jafarabadi, Mohamad Parnianpour, Mahmood-Reza Azghani, Maryam Khosravifar, Sina Samadi,
Volume 10, Issue 1 (7-2022)
Abstract
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.
Narges Adabi, Hassan Sabourimoghaddam, Abbas Bakhsheepour Roodsari,
Volume 10, Issue 3 (12-2022)
Abstract
Objectives: Human factors are critical in the design and development of various products, but wideness and unclarity of different aspects of these factors make it difficult to extract demands of users. Studying emotional aspects of users' behavior in interaction with products, as well as interviewing them, is considered as an efficient tool in extracting design demands. This study aims to integrate the application of task analysis and the measuring of emotional aspects to determine the users’ emotional states in the different stages; and therefore extract the user satisfaction criteria.
Methods: This research has a descriptive/ exploratory approach. In this practical study, the use of two everyday tools for chopping onions is analyzed. 20 users of these tools were non-randomly selected to participate in the test and interview. Users performed the task with each tool, and the process was recorded by a camera. After performing the task, subjects completed self-assessment questionnaire and then, an interview was conducted about their experience of the tools usage. Parametric t test was used to evaluate results of the questionnaire and compare averages.
Results: Findings of the emotional questionnaire showed that the emotional states of people in different stages of task are significantly different from each other. The determined emotional states, showed the weaknesses and the advantages of the tools studied. By analyzing videos, interviews and surveys, users' demands were extracted. The extracted features were categorized based on the work steps.
Conclusion: Using this method can reveal precise details of users’ needs concerning product category, which can be used as a suitable tool for designers and researchers in the field of user experience.
