Tool-specific performance of vibration-reducing gloves for attenuating palm-transmitted vibrations in three orthogonal directions

Vibration-reducing (VR) gloves have been increasingly used to help reduce vibration exposure, but it remains unclear how effective these gloves are. The purpose of this study was to estimate tool-specific performances of VR gloves for reducing the vibrations transmitted to the palm of the hand in three orthogonal directions (3-D) in an attempt to assess glove effectiveness and aid in the appropriate selection of these gloves. Four typical VR gloves were considered in this study, two of which can be classified as anti-vibration (AV) gloves according to the current AV glove test standard. The average transmissibility spectrum of each glove in each direction was synthesized based on spectra measured in this study and other spectra collected from reported studies. More than seventy vibration spectra of various tools or machines were considered in the estimations, which were also measured in this study or collected from reported studies. The glove performance assessments were based on the percent reduction of frequency-weighted acceleration as is required in the current standard for assessing the risk of vibration exposures. The estimated tool-specific vibration reductions of the gloves indicate that the VR gloves could slightly reduce (<5%) or marginally amplify (<10%) the vibrations generated from low-frequency (<25 Hz) tools or those vibrating primarily along the axis of the tool handle. With other tools, the VR gloves could reduce palm-transmitted vibrations in the range of 5%–58%, primarily depending on the specific tool and its vibration spectra in the three directions. The two AV gloves were not more effective than the other gloves with some of the tools considered in this study. The implications of the results are discussed.Relevance to industryHand-transmitted vibration exposure may cause hand-arm vibration syndrome. Vibration-reducing gloves are considered as an alternative approach to reduce the vibration exposure. This study provides useful information on the effectiveness of the gloves when used with many tools for reducing the vibration transmitted to the palm in three directions. The results can aid in the appropriate selection and use of these gloves.     

The effects of vibration-reducing gloves on finger vibration

Vibration-reducing (VR) gloves have been used to reduce the hand-transmitted vibration exposures from machines and powered hand tools but their effectiveness remains unclear, especially for finger protection. The objectives of this study are to determine whether VR gloves can attenuate the vibration transmitted to the fingers and to enhance the understanding of the mechanisms of how these gloves work. Seven adult male subjects participated in the experiment. The fixed factors evaluated include hand force (four levels), glove condition (gel-filled, air bladder, no gloves), and location of the finger vibration measurement. A 3-D laser vibrometer was used to measure the vibrations on the fingers with and without wearing a glove on a 3-D hand-arm vibration test system. This study finds that the effect of VR gloves on the finger vibration depends on not only the gloves but also their influence on the distribution of the finger contact stiffness and the grip effort. As a result, the gloves increase the vibration in the fingertip area but marginally reduce the vibration in the proximal area at some frequencies below 100 Hz. On average, the gloves reduce the vibration of the entire fingers by less than 3% at frequencies below 80 Hz but increase at frequencies from 80 to 400 Hz. At higher frequencies, the gel-filled glove is more effective at reducing the finger vibration than the air bladder-filled glove. The implications of these findings are discussed.     

Evaluation of effects of anti-vibration gloves on manual dexterity

Abstract

The purpose of this study was to evaluate the effects of anti-vibration gloves on manual dexterity and to explore factors affecting the manual dexterity. The manual dexterity of ten different gloves was investigated with 15 adult male subjects via performing two different dexterity tests, namely ASTM F2010 standard test and Two-Hand Turning and Placing Minnesota test. Two-factor repeated-measures analysis of variance was conducted to evaluate the main effects of glove type, test method and their interaction effect on manual dexterity. Results suggested that glove type yielded significant effect on manual dexterity (p?<?.001), while no significant difference was observed between test methods (p?=?.112). The interaction effect of glove type and test method also revealed a significant difference (p?=?.009). The manual dexterity decreased nearly linearly with increase in the glove thickness, which further showed a moderately significant difference on the number of drops during the tests.

Practitioner Summary: Anti-vibration gloves may adversely affect manual dexterity and work precision, which may discourage their usage. This article presented a study of manual dexterity performance of anti-vibration gloves and the design factors affecting the manual dexterity. The results were discussed in view of a design guidance for improved hand dexterity, which would encourage the use of anti-vibration gloves in the workplace.     

Vibration-reducing gloves: transmissibility at the palm of the hand in three orthogonal directions

Vibration-reducing (VR) gloves are commonly used as a means to help control exposures to hand-transmitted vibrations generated by powered hand tools. The objective of this study was to characterise the vibration transmissibility spectra and frequency-weighted vibration transmissibility of VR gloves at the palm of the hand in three orthogonal directions. Seven adult males participated in the evaluation of seven glove models using a three-dimensional hand–arm vibration test system. Three levels of hand coupling force were applied in the experiment. This study found that, in general, VR gloves are most effective at reducing vibrations transmitted to the palm along the forearm direction. Gloves that are found to be superior at reducing vibrations in the forearm direction may not be more effective in the other directions when compared with other VR gloves. This casts doubts on the validity of the standardised glove screening test.

Practitioner Summary: This study used human subjects to measure three-dimensional vibration transmissibility of vibration-reducing gloves at the palm and identified their vibration attenuation characteristics. This study found the gloves to be most effective at reducing vibrations along the forearm direction. These gloves did not effectively attenuate vibration along the handle axial direction.     

Transmission of vibration through gloves: effects of material thickness

It might be assumed that increasing the thickness of a glove would reduce the vibration transmitted to the hand. Three material samples from an anti-vibration glove were stacked to produce three thicknesses: 6.4, 12.8 and 19.2 mm. The dynamic stiffnesses of all three thicknesses, the apparent mass at the palm and the finger and the transmission of vibration to the palm and finger were measured. At frequencies from 20 to 350 Hz, the material reduced vibration at the palm but increased vibration at the finger. Increased thickness reduced vibration at the palm but increased vibration at the finger. The measured transmissibilities could be predicted from the material dynamic stiffness and the apparent mass of the palm and finger. Reducing the dynamic stiffness of glove material may increase or decrease the transmission of vibration, depending on the material, the frequency of vibration and the location of measurement (palm or finger).

Practitioner Summary: Transmission of vibration through gloves depends on the dynamic response of the hand and the dynamic stiffness of glove material, which depends on material thickness. Measuring the transmission of vibration through gloves to the palm of the hand gives a misleading indication of the transmission of vibration to the fingers.     

Methodology for evaluating gloves in relation to the effects on hand performance capabilities: a literature review

The present study was conducted to review the literature on the methods that have been considered appropriate for evaluation of the effects of gloves on different aspects of hand performance, to make recommendations for the testing and assessment of gloves, and to identify where further research is needed to improve the evaluation protocols. Eighty-five papers meeting the criteria for inclusion were reviewed. Many studies show that gloves may have negative effects on manual dexterity, tactile sensitivity, handgrip strength, muscle activity and fatigue and comfort, while further research is needed to determine glove effects on pinch strength, forearm torque strength and range of finger and wrist movements. The review also highlights several methodological issues (including consideration of both task type and duration of glove use by workers, guidance on the selection and allocation of suitable glove(s) for particular tasks/jobs, and glove design features) that need to be considered in future research.

Practitioner Summary: The relevant literature on the effects of protective gloves on different aspects of hand performance was reviewed to make recommendations for the testing and assessment of gloves, and to improve evaluation protocols. The review highlights research areas and methodological issues that need to be considered in future research.     

Transmission of vibration through glove materials: effects of contact force

This study investigated effects of applied force on the apparent mass of the hand, the dynamic stiffness of glove materials and the transmission of vibration through gloves to the hand. For 10 subjects, 3 glove materials and 3 contact forces, apparent masses and glove transmissibilities were measured at the palm and at a finger at frequencies in the range 5–300 Hz. The dynamic stiffnesses of the materials were also measured. With increasing force, the dynamic stiffnesses of the materials increased, the apparent mass at the palm increased at frequencies greater than the resonance and the apparent mass at the finger increased at low frequencies. The effects of force on transmissibilities therefore differed between materials and depended on vibration frequency, but changes in apparent mass and dynamic stiffness had predictable effects on material transmissibility. Depending on the glove material, the transmission of vibration through a glove can be increased or decreased when increasing the applied force.

Practitioner summary: Increasing the contact force (i.e. push force or grip force) can increase or decrease the transmission of vibration through a glove. The vibration transmissibilities of gloves should be assessed with a range of contact forces to understand their likely influence on the exposure of the hand and fingers to vibration.     

A critical review of glove and hand research with regard to medical glove design

Research from a number of areas was surveyed, including hand function; skin friction; manual performance testing; glove comfort, fit and durability; and user perception. The relevance of the research to medical glove design was discussed. It was concluded that, while an understanding has been gained of the factors that affect glove performance in general, specific application to thin rubber gloves has not been well explored. The focus in glove performance testing has also been on simple tasks such as pegboards, which do not necessarily assess the fine dexterity required in many surgical tasks. Recommendations were made for the development of a new battery of tests specific to medical gloves that would simulate real medical tasks and could produce repeatable results and have sufficient resolution to differentiate between glove types.     

Short and longer duration effects of protective gloves on hand performance capabilities and subjective assessments in a screw-driving task

The study investigated short and longer duration effects of gloves on hand performance capabilities (muscle activity, dexterity, touch sensitivity, finger pinch and forearm torque strength) and subjective assessments of discomfort and ease of manipulation when performing a light assembly task. The independent variables were hand condition with four levels (wearing cotton, nylon or nitrile gloves as well as barehanded) and point of time within the 2 h duration of the task (with measurements taken at 0, 30, 60, 90 and 120 min). Participants worked with a screwdriver to fit two components together using screws. Wearing gloves significantly increased the muscle activity, pinch strength and discomfort but reduced the dexterity and touch sensitivity. There was also a significant effect of task time on the muscle activity, dexterity, forearm torque strength and touch sensitivity, which indicates that the duration of the task should be an important consideration in glove evaluation studies and in the selection of work gloves.

Statement of Relevance:It is important to evaluate the effects of gloves on hand performance capabilities in a working context so that job demands can be taken into account and the most appropriate type of glove be chosen for each task. This study gives recommendations regarding the evaluation and use of gloves for screw-driving tasks.     

The development and evaluation of an ergonomic glove

The primary intent of this study was to determine if a hand glove could be designed on a criterion of selective protection. Force distribution patterns on the palmar side of hand were obtained from various studies to develop zones of hand that needed protection. A new design for gloves was developed based on the principle of selective protection, where protective material is introduced in varying levels over different parts of the glove, in order to provide protection where it is most needed, and at the same time preserve the desirable dexterity and strength capabilities of the barehand, optimizing the trade-off between protection and performance. Two pairs of prototype gloves incorporating different levels of protection were fabricated and tested using a battery of performance tests and an algometer test for pressure sensitivity. The test battery comprising four dexterity tasks and a maximal voluntary grip strength task was used to assess a number of glove conditions, including the two prototype gloves developed. The results indicate that the performance of the prototype gloves are comparable, and that the performance times for the double glove and the two prototype gloves tested were not significantly different. For the grip strength, the two prototype gloves were better than the double glove. The assembly task performance for the prototype II (laminar glove) was significantly lower than that of the other glove types tested. It appears that gloves of variable thickness can be developed to afford adequate protection at zones of most need. Glove manufacturers are recommended to use an ergonomic approach in the design of gloves. Such an approach, besides protecting the safety objective of gloves, could enhance productivity considerably.     

An ergonomic evaluation of dexterity and tactility with increase in examination/surgical glove thickness

Latex gloves of five different thicknesses (0·21 mm, 0·51 mm, 0·65 mm, 0·76 mm, and 0·83 mm) were manufactured in-house and tested for dexterity and tactility; dexterity and tactility measures with the bare hand were used as control values. Fifteen adult males (mean age = 22·8 years, mean stature = 179 cm, mean body weight = 75·4 kg, mean palm width = 9·9 cm, mean palm depth = 10·9 cm, and mean middle finger length = 9 cm) and five adult females (mean age = 21·2 years, mean stature = 168 cm, mean body weight = 53·6 kg, mean palm width = 8 cm, mean palm depth = 8 cm, and mean middle finger length = 8·3 cm) voluntarily participated. The gloves also were tested for punctures resulting from impact forces encountered during routine hand movements. The results indicated that the latex glove with 0·83 mm thickness successfully resisted routine impact forces and at the same time provided dexterity and tactility comparable to the bare hand. Thinner gloves failed the impact test and punctured. This indicates that it is possible to greatly reduce the incidence of exposure to contaminated body fluids through accidental needlesticks without compromising the preferred hand's capabilities     

The transmission of vibration through gloves: effects of push force,vibration magnitude and inter-subject variability

The extent to which a glove modifies the risks from hand-transmitted vibration is quantified in ISO 10819:1996 by a measure of glove transmissibility determined with one vibration magnitude, one contact force with a handle and only three subjects. This study was designed to investigate systematically the vibration transmissibility of four ‘anti-vibration’ gloves over the frequency range 16–1600 Hz with 12 subjects, at six magnitudes of vibration (0.25–8.0 ms^?2 r.m.s.) and with six push forces (5 N to 80 N). The four gloves showed different transmissibility characteristics that were not greatly affected by vibration magnitude but highly dependent on push force. In all conditions, the variability in transmissibility between subjects was as great as the variability between gloves. It is concluded that a standardised test of glove dynamic performance should include a wide range of hands and a range of forces representative of those occurring in work with vibratory tools.

Statement of Relevance: The transmission of vibration through anti-vibration gloves is highly dependent on the push force between the hand and a handle and also highly dependent on the hand that is inside the glove. The influence of neither factor is well reflected in ISO 10819:1996, the current standard for anti-vibration gloves.     

Evaluation of the effect of medical gloves on dexterity and tactile sensibility using simulated clinical practice tests

Understanding the effect of medical gloves on manual performance is critical for improving glove design and mitigating the impediment to surgical performance caused by gloves. Existing test methods do not correspond well with clinical and surgical tasks. Based on interviews with clinicians, two new tests were proposed: locating a pulse in a simulated blood vessel, and placing and tying sutures in simulated tissue. A pilot study was carried out using 19 clinicians employed at Sheffield Teaching Hospitals. Subjects performed each test three times, with latex and nitrile examination gloves, and without gloves, the order being randomised. In addition to objective test scores, subjects' perception of their relative performance in each condition was recorded. In the Pulse Location Test, performance was found to be significantly better without gloves, while differences between gloves were not statistically significant. Perceived performance correlated well with measured performance. In the Suturing Test, no statistically significant performance differences were found between the three hand conditions, although subjects perceived ungloved performance to be significantly better than with either the latex or nitrile gloves. The Pulse Location Test showed promise as a clinical performance evaluation tool, and could be used to improve medical glove design for better tactile performance. The discrepancy between subjects' perceived and measured performance in the Suturing Test needs further investigation to determine whether the perceived differences translate into genuine clinical performance differences that were not able to be measured using the current method, or whether the difference is purely psychological.Relevance to industryThe test methods outlined will allow manufacturers to understand the effect of gloves and glove properties on manual performance in medical tasks and improve the design accordingly. Reducing the inhibiting effect of gloves will improve safety and reduce the need to remove gloves for clinical tasks.     

Preliminary study evaluating manual dexterity tests assessing gloves protecting against cuts and stabs by hand knives

The paper presents preliminary results on the research methodology of evaluating the ergonomic properties of gloves protecting against cuts and stabs by hand knives. Four manual dexterity tests were selected for the study: TEST 1: evaluation of fine finger movements pursuant to PN-EN 420; TEST 2: cylinder grip and pull test according to PN-EN 1082 evaluating gross movements of the arms and hands; TEST 3: Purdue Pegboard Test evaluating fine finger movements; TEST 4: evaluation of gross movements of the arms and hands while performing simulated occupational tasks. The tested gloves differed in terms of construction and material (metal mesh or knitwear incorporating a metal yarn) and were selected depending on the scope of work activities performed during meat cutting and boning. The tests were conducted on a homogeneous group of subjects. During the performance of the four dexterity tests, we monitored the loading of four groups of muscles of the upper limb (adductor pollicis, extensor carpi radialis, flexor carpi ulnaris, and biceps brachii) using surface electromyography (EMG). Additionally, subjective sensations concerning the strain on the upper limb were evaluated using a questionnaire survey.The objective of the study was to identify a group of tests that would be characterized by high sensitivity and ensure reliable assessment of gloves protecting against cuts and stabs by hand knives. The results showed that not all of the dexterity captured differences in the way the gloves affected dexterity. This was corroborated by electromyographic measurements, which revealed considerable differences in load of upper limb muscles when using various gloves and further supported by the subjective sensations of the participants, as reported in the questionnaire study. It was concluded that in order to reliably evaluate the ergonomic properties of gloves protecting against cuts and stabs by hand knives it is necessary to design new dexterity tests that would reflect actual workplace conditions, and could simulate occupational activities. Workplace observations helped to identify specific aspects of manual dexterity (fine, medium, gross), and types of hand movement associated with professional activities including different force configurations (finger flexion, wrist abduction, and pressing with the fingers and wrist). Based on those observations three new manual dexterity tests dedicated exclusively to evaluation of the ergonomic properties of gloves protecting against cuts and stabs by hand knives have been proposed.     

Short and longer duration effects of protective gloves on hand performance capabilities and subjective assessments in a screw-driving task

The study investigated short and longer duration effects of gloves on hand performance capabilities (muscle activity, dexterity, touch sensitivity, finger pinch and forearm torque strength) and subjective assessments of discomfort and ease of manipulation when performing a light assembly task. The independent variables were hand condition with four levels (wearing cotton, nylon or nitrile gloves as well as barehanded) and point of time within the 2 h duration of the task (with measurements taken at 0, 30, 60, 90 and 120 min). Participants worked with a screwdriver to fit two components together using screws. Wearing gloves significantly increased the muscle activity, pinch strength and discomfort but reduced the dexterity and touch sensitivity. There was also a significant effect of task time on the muscle activity, dexterity, forearm torque strength and touch sensitivity, which indicates that the duration of the task should be an important consideration in glove evaluation studies and in the selection of work gloves. STATEMENT OF RELEVANCE: It is important to evaluate the effects of gloves on hand performance capabilities in a working context so that job demands can be taken into account and the most appropriate type of glove be chosen for each task. This study gives recommendations regarding the evaluation and use of gloves for screw-driving tasks.     

How do medical gloves affect manual performance? Evaluation of ergonomic indicators

Medical gloves have a direct effect on the safety of clinical staff and patients as well as optimal performance. Thus, it is necessary to identify the quantitative impact of gloves on hand performance indicators. This study aimed to investigate the effect of medical gloves on manual performance. This study was conducted on 40 hospital clinical staff. The participants’ dexterity, tactile sensitivity, and grip strength were evaluated with and without gloves and were compared by Purdue pegboard, two-point discrimination, and dynamometer tests. Additionally, the participants were required to rate their performance under different conditions using the visual analogue scale. The results showed that medical gloves had a significant effect on all studied indices. Double gloving caused the most significant reduction in touch sensitivity. Grip strength was also significantly reduced by the use of inappropriate gloves. Despite its negative effects on the ergonomic indices, single gloving provided the same functional performance as did the condition without gloves.Relevance to industryDespite a significant decrease in manual performance, single gloving can be a good alternative for the condition without gloves with regard to individuals’ mental performance. The present study results also indicated that medical gloves had a significant impact on ergonomic indicators related to manual performance. Hence, it is necessary to consider manual function dimensions when designing gloves.     

Design options for improving protective gloves for industrial assembly work

The study investigated the effects of wearing two new designs of cotton glove on several hand performance capabilities and compared them against the effects of barehanded, single-layered and double cotton glove conditions when working with hand tools (screwdriver and pliers). The new glove designs were based on the findings of subjective hand discomfort assessments for this type of work and aimed to match the glove thickness to the localised pressure and sensitivity in different areas of the hand as well as to provide adequate dexterity for fine manipulative tasks. The results showed that the first prototype glove and the barehanded condition were comparable and provided better dexterity and higher handgrip strength than double thickness gloves. The results support the hypothesis that selective thickness in different areas of the hand could be applied by glove manufacturers to improve the glove design, so that it can protect the hands from the environment and at the same time allow optimal hand performance capabilities.     

The transmission of vibration through gloves: effects of push force, vibration magnitude and inter-subject variability

The extent to which a glove modifies the risks from hand-transmitted vibration is quantified in ISO 10819:1996 by a measure of glove transmissibility determined with one vibration magnitude, one contact force with a handle and only three subjects. This study was designed to investigate systematically the vibration transmissibility of four 'anti-vibration' gloves over the frequency range 16-1600 Hz with 12 subjects, at six magnitudes of vibration (0.25-8.0 ms(-2) r.m.s.) and with six push forces (5 N to 80 N). The four gloves showed different transmissibility characteristics that were not greatly affected by vibration magnitude but highly dependent on push force. In all conditions, the variability in transmissibility between subjects was as great as the variability between gloves. It is concluded that a standardised test of glove dynamic performance should include a wide range of hands and a range of forces representative of those occurring in work with vibratory tools. STATEMENT OF RELEVANCE: The transmission of vibration through anti-vibration gloves is highly dependent on the push force between the hand and a handle and also highly dependent on the hand that is inside the glove. The influence of neither factor is well reflected in ISO 10819:1996, the current standard for anti-vibration gloves.     

Extended artificial chromosomes genetic algorithm for permutation flowshop scheduling problems

In our previous researches, we proposed the artificial chromosomes with genetic algorithm (ACGA) which combines the concept of the Estimation of Distribution Algorithms (EDAs) with genetic algorithms (GAs). The probabilistic model used in the ACGA is the univariate probabilistic model. We showed that ACGA is effective in solving the scheduling problems. In this paper, a new probabilistic model is proposed to capture the variable linkages together with the univariate probabilistic model where most EDAs could use only one statistic information. This proposed algorithm is named extended artificial chromosomes with genetic algorithm (eACGA). We investigate the usefulness of the probabilistic models and to compare eACGA with several famous permutation-oriented EDAs on the benchmark instances of the permutation flowshop scheduling problems (PFSPs). eACGA yields better solution quality for makespan criterion when we use the average error ratio metric as their performance measures. In addition, eACGA is further integrated with well-known heuristic algorithms, such as NEH and variable neighborhood search (VNS) and it is denoted as eACGA_hybrid to solve the considered problems. No matter the solution quality and the computation efficiency, the experimental results indicate that eACGA_hybrid outperforms other known algorithms in literature. As a result, the proposed algorithms are very competitive in solving the PFSPs.     

Training and assessing non-technical skills a practical guide

The effect of gloves on the spatio-temporal characteristics of prehensile forces during lifting and holding tasks was investigated. Participants (n= 10) lifted a force transducer equipped object (weight = 0.29 N) with various types of gloves and barehanded using a two-fingered precision grip. Rubber surgical gloves of varied thicknesses (0.24, 0.61 and 1.02 mm) were worn to examine the effect of glove thickness on a rayon surface. It was found that grip force increased with thickness because the participants employed a higher safety margin above the minimum force required to hold the object. The safety margin for the barehanded condition was the smallest. The performance time for lifting the object was not influenced by the variation of glove thickness. The findings suggest that glove thickness, which presumably modifies the cutaneous sensation, influences grip force regulation. The effect of glove material (rubber and cotton) was also examined in relation to slippery (rayon) and non-slippery (sandpaper) surfaces. It was found that the participants used a larger grip force with the cotton glove than the rubber glove for the slippery surface, but not with the non-slippery surface. With use of the rubber glove, a relatively low grip force level was maintained for both slippery and non-slippery surfaces. The performance time for the cotton glove was longer than that for the rubber glove. The findings suggest that the rubber glove provides better efficiency of force and temporal control than the cotton glove in precision handling of small objects.