Hand-held Tools Research Articles

Compatibility as guiding principle for ergonomics work design and preventive occupational health and safety

Mutual adaptation and inter-changeability of system elements are very important prerequisites for machines, technical devices and products. Similar to that technical compatibility which can be achieved by standards and regulations, optimum design of human-oriented workplaces or a man-machine system cannot be attained without, e.g., a compatible arrangement of connected displays and controls. Over and above those stimulus/response relations, all technical elements and interfaces have to be designed in such a way that they do not exceed human capacity in order to optimize human well-being and overall system performance. Compatibility between the properties of the human organism on the one hand, and the adaptable technical components of a work system on the other hand, offers a great potential of preventive measures. Examples of ergonomically designed working tools show that compatibility is capable of reducing the prevalence of occupational diseases and repetitive strain injuries as well as leading to lower physiological cost in such a way that the same output results from a lower demand of human resources or even a higher performance will be attained. Compatibility also supports the quick perception and transmission of information in a man-machine system, and as a result of lower requirements for decoding during information processing, spare mental capacity may enhance occupational safety. In the field of software, compatibility also helps to avoid psychological frustration. All in all, the center core competency, which reflects the major significant function of the ergonomist in work design, consists in determining the compatibility of human capacity and planned or existing demands of work. In order to provide efficient working tools and working conditions as well as to be successful in occupational health and safety, ergonomics and industrial engineering in the future are expected to pay more attention to the rules of compatibility. Applied in an appropriate way, these rules may convince people that ergonomics can be a powerful means for reducing prevalence of occupational diseases and complaints, and has a positive effect on overall system performance. Besides presenting examples of work design according to the principle of compatibility, also methods will be shown which enable the assessment of the ergonomic quality of hand-held tools and computer input devices.

WORK MEASUREMENT STUDY ON MOTOR-MANUAL PINE TAPPING OPERATION: THE APPLICATION OF THE CONCEPT OF LEAN MANUFACTURING AND ALLOWANCES

Derivated products of pine resin have been recognised as competitive commodities in global trade, increasing the need to use resources more efficiently. A hand-held tapping machine with small hoe-shape cutters called “mujitek” has been widely applied in Indonesia among efforts to answer this challenge. In this study, a series of observed (actual) work time data were measured and analysed, adopting lean manufacturing to calculate the basic and standard time of the work and estimate the work produced on the tapping operation. Work elements were identified based on their contribution to change or transform the product and were categorised as value-added, non-value-added, and special allowance. Quantitative data on the work productivity in the tapping operation can be used as one fundamental data in determining a work plan to establish a continuous improvement process. The variable fatigue allowances taken into account in this study were standing posture, abnormal posture, muscular energy, atmospheric conditions, and noise. This study shows that non-value-added work elements (repairing machines, chatting, and smoking) cause inefficiency in tapping operation. Analysis of added-value work elements proved that this hand-held tapping machine offers a higher (1.7 times) work productivity than conventional hand-held tapping tools. However, since humans have limitations in the physical, physiological, and mental dimensions that limit their ability to carry out work at a certain level, the discovered work productivity level should also be validated with other thresholds, e.g., physical workload and risk perception.

Mechanical Imaging of Soft Tissues With Miniature Climbing Robots.

Systematically mapping the mechanical properties of skin and tissue is useful for biomechanics research and disease diagnostics. For example, later stage breast cancer and lymphoma manifest themselves as hard nodes under the skin. Currently, mechanical measurements are done manually, with a sense of touch or a handheld tool. Manual measurements do not provide quantitative information and vary depending on the skill of the practitioner. Research shows that tactile sensors could be more sensitive than a hand. We propose a method that uses our previously developed skin-crawling robots to noninvasively test the mechanical properties of soft tissue. Robots are more systematic and repeatable than humans. Using the data collected with a cutomoter or indenter integrated into the miniature robot, we trained a convolutional neural network to classify the size and depth of the lumps. The classification works with 98.8% accuracy for cutometer and 99.6% for indenter for lump size with a diameter of 0 to 10 mm embedded in depth of 1 to 5 mm in a simulated tissue. We conducted a limited evaluation on a forearm, where the robot imaged dry skin with a cutometer. We hope to improve the ability to test tissues noninvasively, and ultimately provide better sensitivity and systematic data collection.

ОСОБЛИВОСТІ ЕРГОНОМІЧНОЇ ОЦІНКИ РУЧНОГО ЕЛЕКТРОІНСТРУМЕНТА

Hand-held power tools are an integral part of any manufacturing process. Modern power tools are characterized by operational, consumer, ergonomic and safety properties. These properties characterize its effective adaptability to the relevant production process. But it should also be noted that not taking into account the ergonomic properties: noise load, vibration, tool weight, heating temperature of the working surface of the tool, etc. causes very serious consequences for the deterioration of the health of the employee who uses it. This is especially true for occupational diseases of the circulatory system, nervous system, diseases of the bone and vascular tissue. Object of the study – development of a fast-effective method for assessing the ergonomic risk of hand-held power tools when performing a specific production task Purpose of the study – ergonomic risk when working with hand tools when performing the appropriate technological process. Method of the study – the research method is based on observations and studies of specific phenomena of the process under consideration, as well as the generalization of the results of experimental research and their implementation in practice. Results of the study – the most influential criteria that affect employee productivity when working with hand tools are identified: integrated design ergonomics, load, tool weight, jerk load, tool surface heating temperature, vibration, noise, dust particles during tool operation. For each criterion the corresponding estimation of ergonomic risk taking into account influence on a physical, psychological condition of the worker is proved. A checklist has been developed to determine the level of ergonomic risk according to eight criteria. Keywords: hand power tools, ergonomic risk, indicator, harmful factors, occupational diseases, checklist.

Hand-arm vibration on dentists using ready reckoner: A cross-sectional study

Context: Rising incidence of hand-arm vibration on dentists is an increasing concern in India. The purpose of this study is to investigate the dose-response relationship derived using ready reckoner and to identify the most practicable exposure action and limit value measure that can be collected to aid in the health assessment of dentists exposed to hand-arm vibration. Aims: The objective of this research is to determine the magnitude of vibration transmitted per day among dentists exposed to the vibrating hand-held tools; To determine the association of the magnitude of vibration transmission with duration of usage and to determine the proportion of Exposure Action Value (EAV) and Exposure Limit Value (ELV) among dentists. Methods and Materials: Using a cross-sectional analysis, this study analyzed the incidence of hand-arm vibration on 92 dentists and measured these results with a ready reckoner. Statistical analysis used: Chi-Square Test was used to test the association of vibration exposure with selected parameters that is of interest such as years of experience, duration of work, vibration magnitude of the instrument. Results: The proximity of middle-aged dentists with more than or equal to 10 years of working experience were found to play a huge role in exposure to hand-arm vibration. Conclusions: This study definitely answers the questions regarding the exposure to hand-arm vibration on dentists. This could be minimized reducing exposure times, health surveillance, improved handpieces and other equipment and improving the overall ergonomics of the workplace. Keywords: Dentistry, Exposure assessment, Handarm vibration, Health surveillance.

A systematic review of handheld tools in lieu of colposcopy for cervical neoplasia and female genital schistosomiasis.

BackgroundVisualization of the lesions in the lower genital tract is the mainstay for diagnosis of the four lesions found in female genital schistosomiasis (FGS), but colposcopes are generally not available in low‐resource settings.ObjectiveWe sought to review handheld devices that could potentially be used for FGS diagnosis.Search strategyWe searched Medline and Embase 2015–2019 for handheld devices used in cervical cancer screening and FGS diagnosis.Selection criteriaWe excluded studies that did not compare the device to standard‐of‐care colposcopes or histopathology.Main results and conclusionIn 11 studies, four handheld colposcopes, two smartphones, and one compact digital camera were evaluated. Two handheld colposcopes were found to be potentially adequate for FGS diagnosis, namely Gynocular and Mobile ODT. The smartphones and digital camera did not have sufficient magnification to diagnose grainy sandy patches, one of the FGS lesion types. Customized software should be made to support the diagnosis of both FGS and cervical neoplasia. Real‐time postgraduate training and quality control should be considered in future studies of handheld colposcopes. For patients from schistosomiasis endemic areas, we recommend that handheld devices are used for FGS. Studies are needed to determine which of the two devices is most adequate for FGS diagnosis in schistosomiasis endemic areas.

Sex differences in deterioration of sleep properties associated with aging: a 12-year longitudinal cohort study.

The sleep patterns of humans are greatly influenced by age and sex and have various effects on overall health as they change continuously during the lifespan. We investigated age-dependent changes in sleep properties and their relation to sex in middle-aged individuals. We analyzed data from 2,640 participants (mean age of 49.8 ± 6.8 years at baseline, 50.6% women) in the Korean Genome and Epidemiology Study, which assessed sleep habits using the Pittsburgh Sleep Quality Index and other clinical characteristics. We analyzed the sleep habit changes that occurred between baseline and a follow-up point (mean interval: 12.00 ± 0.16 years). Associations of age and sex with 9 sleep characteristics were evaluated. Age was associated with most of the sleep characteristics cross-sectionally and longitudinally (P < .05), except for the time in bed at baseline (P = .455) and change in sleep duration (P = .561). Compared with men, women had higher Pittsburgh Sleep Quality Index scores, shorter time in bed, shorter sleep duration, and longer latency at baseline (P ≤ .001). Longitudinal deterioration in Pittsburgh Sleep Quality Index score, habitual sleep efficiency, duration, and latency was more prominent in women (P < .001). The sex differences in these longitudinal sleep changes were mainly noticeable before age 60 years (P < .05). Worsening of Pittsburgh Sleep Quality Index scores, habitual sleep efficiency, and latency was most evident in perimenopausal women. Men presented with greater advancement of chronotype (P = .006), with the peak sex-related difference occurring when they were in their late 40s (P = .048). Aging is associated with substantial deterioration in sleep quantity and quality as well as chronotype advancement, with the degree and timing of these changes differing by sex.

A Smart Operator Assistance System Using Deep Learning for Angle Measurement

Manual workstations play a critical role in flexible assembly lines by enabling human responses to reconfiguration that is faster than machine responses. As a result, human is more adaptive and sometimes unreplaceable by machines in complex assembly. However, with the increasing complexity of tasks, product quality has become highly susceptible to human error due to increments in operators’ cognitive load. One of the errors that affect assembly quality is the operator’s use of a handheld tool with an unfavorable working angle when handling the workpiece. In this case, an assistive mechanism to remind workers about the wrong working angle is necessary to support the process. To this end, this study proposes an angle monitoring system to inspect the working angle of handheld tools and provide feedback in real time with minimal interruption to the assembly process. The proposed system consists of an angle measurement model and an action recognition model, which are both built using deep-learning-based object detection algorithm. Besides, the system was designed with flexibility that it is applicable to different tools and assembly tasks. A case study on fastening a high-end graphical processing unit card is investigated to evaluate their performance. Results show 95.83% and 99.83% accuracies of the models. In practice, the proposed study is expected to facilitate assembly quality by preventing the failure of angle-related operations in a timely and reliable manner.

Чжурчжэньские орудия для уборки урожая (по материалам Шайгинского городища)

Purpose. The article is dedicated to the research of harvesting tools that were excavated on the territory of the Shaiginskoe site. For the first time, the full statistics of the material are given, its new classification has been developed, and the data reveal the role of agriculture in life in the military-agricultural settlements of the State of East Xia. The Jurchens’ walled towns dating back to the period of the Eastern Xia State are qualified as military and agricultural settlements. Fortification structures of the sites imply their military functions, whereas findings of agricultural equipment affirm respective activities of the citizens. The agricultural implements excavated on the site of Shaiginskoe include hand-held tools typically used by the Jurchen people for harvesting cereal crops or cutting grass for hay. The article covers a complete statistic of the archaeological findings, provides a new type of their classification and demonstrates the scientists’ efforts to determine the specific features of social relations in military and agricultural settlements. Results. A total of 113 items have been found in the Shayginskoe settlement, which can be attributed to tools for harvesting. According to morphological features, they can be divided into species A – sickles and species B – scythes. Having analyzed the unearthed material, the authors conclude that the tools had a cross-purpose and their functions were not clearly separated. The Jurchens’ sickle appeared to be similar to the sickle-scythe used by the Manchus. They correspond to each other in size, shape and functionality. The only difference lies in a manner of fastening the blade to the handle. Conclusion. Judging by the number of agricultural equipment found in almost one in three dwellings of The Shaiginskoe fortification, it can be concluded that many residents of the city, to varying degrees, engaged in agriculture, supplemented by fishing and hunting, providing themselves with food, however agriculture played an important role in the economy of medieval fortifications of Primorye, and formed the basis of agricultural activity of the Jurchen.

Design and Control of a Hand-Held Concentric Tube Robot for Minimally Invasive Surgery

Minimally invasive surgery is of high interest for interventional medicine since the smaller incisions can lead to less pain and faster recovery for patients. The current standard-of-care involves a range of affordable, manual, hand-held rigid tools, whose limited dexterity and range of adoptable shapes can prevent access to confined spaces. In contrast, recently developed roboticized tools that can provide increased accessibility and dexterity to navigate and perform complex tasks often come at the cost of larger, heavier, and grounded devices that are teleoperated, posing a new set of challenges. In this article, we propose a new hand-held concentric tube robot with an associated position control method that has the dexterity and precision of large roboticized devices, while maintaining the footprint of a traditional hand-held tool. The device shows human-in-the-loop control performance that meets the requirements of the targeted application, percutaneous abscess drainage. In addition, a small user study illustrates the advantage of combining rigid body motion of the device with more precise motions of the tip, thus showing the potential to bridge the gap between traditional hand-held tools and grounded robotic devices.

Integrated Augmented Reality Feedback for Cochlear Implant Surgery Instruments

In this article, we present a visualization system to provide assistance in cochlear implant surgery which can be seamlessly integrated within the devices that are currently used in surgery. The system is intended to improve tool alignment in positioning and during insertion, with the aim of reducing the problems encountered during perimodiolar electrode array insertion. Our system is composed of a semi-autonomous hand-held surgical tool, coupled with an optical tracker to monitor the tool position and an operating microscope. The microscope live view is overlaid with guidance information in the form of augmented reality to assist the surgeon in positioning the surgical tool and maintain that position during insertion. Our approach shows promising results in tool alignment, which are comparable to the state of the art.

Design Synthesis and Preliminary Evaluation of a Novel Tool to Noninvasively Characterize Pressurized, Physiological Vessels

Abstract A prolonged increase in intra-abdominal pressure (IAP) is life-threatening, yet commonly seen in intensive care units (ICUs). Despite this, existing clinically accepted IAP measurement techniques are invasive and not inter-rater reliable. As such, it is the effort of this research to develop a direct, noninvasive, handheld tool to measure internal pressures in pressurized, physiological vessels. The novel device uses a localized known pressure (namely, aspiration) to measure resulting tissue deformation, from which internal pressures can be divulged considering the extended Hencky solution. Two male participants were tested with the device to confirm feasibility of the theoretical device function for IAP measurement. Participants' Young's moduli of the abdominal wall were calculated with measured IAP values. Results were consistent with participant body mass indices and overall health. Average measured IAP was 0.42 kPa and 0.46 kPa at supine and inclined positions, respectively. Average measured abdominal wall elasticity was 14.91 kPa and 23.09 kPa at supine and inclined positions, respectively. These preliminary findings suggest the potential use of the device described herein as a measurement system for pressurized vessels, whereas the system will be tested on a larger sample size before recommending clinical use.

Do Not Cut Wood with an Angle Grinder, or You Might Lose a Finger: A Retrospective Study.

Background: Angle grinders are a handheld power tool used for grinding and polishing stone, metal, and concrete. Some people, however, use them with a circular saw blade attachment for cutting wood and consequently, suffer injuries. We aimed to investigate the underlying cause and mechanisms of injuries caused by cutting wood with an angle grinder. Methods: We conducted a retrospective study using medical records from our trauma center and identified 15 patients treated for angle grinder injury between 2017 and 2018. Moreover, we contacted the National Consumer Affairs Center of Japan for further information about angle grinder injuries. Results: Nine of the 15 patients used angle grinders improperly, of which only three patients were aware of the risk of injury. The details of the nine patients were as follows: the types of injuries: complete finger amputation (n = 2), partial finger amputation (n = 1), tendon injury with phalangeal fracture (n = 5), and tendon injury alone, (n = 1); the causes of accidents: kickback (n = 7) and glove entanglement (n = 2); and the accident situations: on-the-job (n = 5) and do-it-yourself (n = 4). Conclusions: The primary cause of angle grinder injury caused by cutting wood was a lack of user knowledge that an angle grinder cannot be used as a cutting tool. Appropriate feedback from hand surgeons are necessary to urge manufacturers to take safety measures.

Analogous adaptations in speed, impulse and endpoint stiffness when learning a real and virtual insertion task with haptic feedback

Humans have the ability to use a diverse range of handheld tools. Owing to its versatility, a virtual environment with haptic feedback of the force is ideally suited to investigating motor learning during tool use. However, few simulators exist to recreate the dynamic interactions during real tool use, and no study has compared the correlates of motor learning between a real and virtual tooling task. To this end, we compared two groups of participants who either learned to insert a real or virtual tool into a fixture. The trial duration, the movement speed, the force impulse after insertion and the endpoint stiffness magnitude decreased as a function of trials, but they changed at comparable rates in both environments. A ballistic insertion strategy observed in both environments suggests some interdependence when controlling motion and controlling interaction, contradicting a prominent theory of these two control modalities being independent of one another. Our results suggest that the brain learns real and virtual insertion in a comparable manner, thereby supporting the use of a virtual tooling task with haptic feedback to investigate motor learning during tool use.

Expert tool users do not visually embody their hand-held tool

Expert tool users do not visually embody their hand-held tool

The GoAudio Quantitative Mobile Audiology Test Enhances Access to Clinical Hearing Assessments.

Purpose Hearing loss is a common impairment of the human senses with an estimated 48 million American adults reporting some trouble hearing; however, access to hearing health care is limited. Detection of hearing loss through a mobile, handheld tool can provide an important access point and potentially expedited access to the continuum of hearing health care. Here, we determined that GoAudio, a portable, automated hearing assessment tool, can be used to identify individuals who require additional hearing evaluation in a clinical workflow. Method This initial study included 24 adults, ages 18-65 years (M = 50, SD = 12), tested with GoAudio versus "gold-standard" clinical audiometry for eight frequencies to evaluate "real-world" applications. Participants utilized noise-canceling headphones combined with a tablet-based application for the GoAudio assessment. Results The primary study outcome measurements were the comparison of hearing thresholds (dB HL) from clinical audiometry and GoAudio. Results suggest that GoAudio is comparable to clinical audiometry for the identification of hearing loss at most frequencies (except 1 kHz for both ears and 2 kHz in the right ear). Upon stratifying data based on age, we identified that GoAudio is capable of identifying suspected age-related hearing loss or hearing thresholds greater than 30 dB HL at higher frequencies in both ears. Conclusion The study results support that GoAudio can be used effectively in clinical practice workflows as a reliable hearing assessment tool for the identification of hearing loss at the majority of frequencies outside a sound-treated booth and can detect characteristics of age-related hearing loss. Supplemental Material https://doi.org/10.23641/asha.13087682.

Design and characterization of an instrumented hand-held power tool to capture dynamic interaction with the workpiece during manual operations

In recent years, robots have contributed extensively to the automation of repetitive tasks for which position control-based approaches represent effective solutions. However, other contact tasks such as finishing, deburring and grinding require both position and force control. To date, despite the availability of cost-effective robotic solutions, such tasks are still carried out manually by skilled operators mainly because programming is time consuming and not sufficiently flexible to be readapted to product or task changes. An alternative approach is teaching by demonstration, by instrumenting hand-held tools for capturing both the force and the contact point while an expert operator performs tooling tasks. This paper presents a novel approach for instrumenting hand-held tools for polishing/grinding used in monitoring the performance of skilled human operators which can be, in future work, translated into planning strategies for robot programming and control. More specifically, the instrumented tool is designed to monitor interaction forces with the workpiece and point of contact, where these interaction forces arise. The key element in our design is a flexible coupler which, ideally, only transmits rotation torques to spin the polishing/grinding wheel while all the remaining torque and force components are transmitted through a parallel structure and sensed by a 6-axis loadcell. Sensing torques, in addition to forces, also allows for a dynamic estimation of the point of contact.

Vision is biased near handheld, but not remotely operated, tools.

Previous studies have shown that after actively using a handheld tool for a period of time, participants show visual biases toward stimuli presented near the end of the tool. Research suggests this is driven by an incorporation of the tool into the observer's body schema, extending peripersonal space to surround the tool. This study aims to investigate whether the same visual biases might be seen near remotely operated tools. Participants used tools-a handheld rake (Experiment 1), a remote-controlled drone (Experiment 2), a remote-controlled excavator (Experiment 3), or a handheld excavator (Experiment 4)-to rake sand for several minutes, then performed a target-detection task in which they made speeded responses to targets appearing near and far from the tool. In Experiment 1, participants detected targets appearing near the rake significantly faster than targets appearing far from the rake, replicating previous findings. We failed to find strong evidence of improved target detection near remotely operated tools in Experiments 2 and 3, but found clear evidence of near-tool facilitation in Experiment 4 when participants physically picked up the excavator and used it as a handheld tool. These results suggest that observers may not incorporate remotely operated tools into the body schema in the same manner as handheld tools. We discuss potential mechanisms that may drive these differences in embodiment between handheld and remote-controlled tools.

A rapid food chain approach for authenticity screening: The development, validation and transferability of a chemometric model using two handheld near infrared spectroscopy (NIRS) devices

This study assesses the application of a handheld, near infrared spectroscopy (NIRS) device, namely the NeoSpectra Micro, for the determination of oregano authenticity. Utilising a large sample set of oregano (n = 295) and potential adulterants of oregano (n = 109), models were developed and validated using SIMCA 15 software. The models demonstrated excellent predictability for the determination of authentic oregano and adulterant samples. The optimal model resulted in a 93.0% and 97.5% correct prediction for oregano and adulterants, respectively. Different standardisation approaches were assessed to determine model transferability to a second NIRS device. In the case of the second device, the best predictions were achieved with data that had not undergone any spectral standardisation (raw). Subsequently, the optimal model was able to correctly predict 90% of authentic oregano samples and 100% of the adulterant samples on the second device. This study demonstrates the potential of the device to be used as a simple, cost effective, reliable and handheld screening tool for the determination of oregano authenticity, at various stages of the food supply chain. It is believed that such forms of monitoring could be highly beneficial in other areas of food authenticity analysis to help combat the negative economical and health implications of food fraud.

It doesn't add up: Nested affordances for reaching are perceived as a complex particular.

In the Ecological Approach to Perception and Action, affordances are emergent, higher-order relationships in an animal-environment system. In addition, perceivers should perceive such relationships directly, rather than by combining lower-order constituents of the affordance, such as non-affordance properties of the animal or the environment. In the present study, we investigated whether this latter claim applied to perception of superordinate affordances - affordances that emerge from relations between lower-order affordances. We asked whether perception of a superordinate affordance for reaching by different means would be reducible to a combination of lower-order constituents of that affordance. Participants reported the maximum height that they would be able to reach with their arm alone versus with a hand-held tool. In both cases, reported judgments of maximum reaching height differed from an additive model in which values were computed from a combination of perceived lower-order constituents of the affordance. The results are consistent with the ecological claim that affordances are perceived, "as such," rather than being computed or inferred from constituent properties, even when those constituent properties are, themselves, affordances.