The design and development of suspended handles for reducing hand-arm vibration in petrol driven grass trimmer

The portable petrol driven grass trimmer is identified as a type of machine whose operator can be subjected to large magnitude of hand-arm vibration. These vibrations can cause complex vascular, neurological and musculoskeletal disorder, collectively named as hand-arm vibration syndrome. The vibration total level on the handle of grass trimmer of 11.30 m/s² was measured, and it has reached the exposure limit value of 5.0 m/s² for daily vibration exposure A(8). New suspended handles were designed to reduce the vibration level. Three different prototype handles with rubber mounts were designed. Handles were made of different materials, and the distance of rubber mounts were varied. From the study, it was observed that not all the handles with rubber mounts were effective in reducing hand-arm vibration. The reduction of vibration depended on the handle material and distance installed between rubber mount and vibration transmissibility of handle-isolation system. Subjective ratings of perception of vibration were measured, and the results indicated that operators were not fully aware of the level of vibration. A prototype handle that is made of heavier material results in the lowest hand-arm vibration of 2.69 m/s². The new handle has significantly reduced the vibration total value by 76% compare with the existing commercial handle.

Relevance to industry

Large numbers of workers are employed to perform grass trimming job in many developing countries. This paper presents the effect of handle types (commercial and prototype) on the commonly used grass trimmer.     

一种互联网资源标志与寻址技术:Handle System

互联网最基础的资源标志与寻址技术是域名和IP地址，随着互联网资源种类的增加，以及应用的发展，出现了对新一代互联网资源标志与寻址技术的需求。介绍了一种新的互联网资源标志与寻址技术，并将这种技术应用到域名系统中。     

Evaluation of handle design characteristics in a maximum screwdriving torque task

The purpose of this study was to evaluate the effects of screwdriver handle shape, surface material and workpiece orientation on torque performance, finger force distribution and muscle activity in a maximum screwdriving torque task. Twelve male subjects performed maximum screw-tightening exertions using screwdriver handles with three longitudinal shapes (circular, hexagonal and triangular), four lateral shapes (cylindrical, double frustum, cone and reversed double frustum) and two surfaces (rubber and plastic). The average finger force contributions to the total hand force were 28.1%, 39.3%, 26.5% and 6.2%, in order from index to little fingers; the average phalangeal segment force contributions were 47.3%, 14.0%, 20.5% and 18.1% for distal, middle, proximal and metacarpal phalanges, respectively. The plastic surface handles were associated with 15% less torque output (4.86 Nm) than the rubber coated handles (5.73 Nm). In general, the vertical workpiece orientation was associated with higher torque output (5.9 Nm) than the horizontal orientation (4.69 Nm). Analysis of handle shapes indicates that screwdrivers designed with a circular or hexagonal cross-sectional shape result in greater torque outputs (5.49 Nm, 5.57 Nm), with less total finger force (95 N, 105 N). In terms of lateral shape, reversed double frustum handles were associated with less torque output (5.23 Nm) than the double frustum (5.44 Nm) and cone (5.37 Nm) handles. Screwdriver handles designed with combinations of circular or hexagonal cross-sectional shapes with double frustum and cone lateral shapes were optimal in this study.     

Evaluation of ergonomic adjustments of catering carts to reduce external pushing forces

An existing standard catering cart was compared with two prototypes for pushbar and castor design. The first objective of this study was to find out which cart was accompanied with the lowest manually exerted external forces in pushing in a straight way and in pushing a 90 turn. The second objective was to explore effects of the pushbar and castor design of the carts. In the initial and ending phase, the prototypes were accompanied with higher exerted forces compared with the standard catering cart. In pushing straight. the reversed start position of the bigger castors of the prototypes hampered a fluent acceleration and caused higher initial forces. In decelerating, the lower rolling friction of the bigger castors required higher forces to stop the prototypes compared to the standard cart. During the sustained phase, the prototype carts were more favourable. Effects of pushbar and castor design were studied during a turn. The vertical pushbars of the prototypes resulted in lower time-integrated pushing forces. Providing an axis of rotation for turning activities by means of a fixed wheel was proven to be advantageous.     

一种快速自动处理图片的工具软件

本文设计了一种能够快速自动处理大批图片的工具软件，实践表明，该工具简单、实用，大大地提高了办公效率。     

涤双绉风格特征与织物结构

本文基于表征涤双绉风格特征的力学参量，运用多元回归分析法，分析和讨论了织物力学性能与结构参数的关系。研究结果表明：纬向收缩率是最重要的参数，一般纬缩率保持在６％～１２％为最佳值。在此基础上提出了设计涤双绉的要素及相应的参数值。     

纺织面料的发展趋势与新材料技术的应用

论述了纺织面料的发展趋势，介绍了新材料，新技术在棉纺织工程中的应用以及加入WTO后的应对策略。指出了纺织面料应脱离传统棉纺织产品的风格，面貌、手感及概念，应以毛型产品的手感和外观为主，兼具丝绸产品的外观，滑爽感和光泽，并具备某些新功能，向轻薄化方向发展。     

脉冲堆堆内垂直孔道、偏心腔孔道操作工具结构设计与分析

介绍了堆内垂直孔道、偏心腔孔道操作工具结构设计的设计准则及特点，分析了利用重力作用进行定位、导向、复位，从而形成操作动作的工作原理和可快速换头的工具结构、以及该结构方案所具有的特点。实际操作试验表明，该工具是操作堆内垂直孔道、偏心腔孔道的理想工具。     

The effect of knife handle shape on stabbing performance

A quantitative knowledge of stabbing ability is a pre-requisite to establishing protection standards for stab resistant body armour. In order to determine the validity of measurements it is necessary to understand all the mechanisms that determine performance. This paper describes a series of tests that were performed in order to determine the effect of handle size and shape on the forces and impact energy that could be produced during stabbing of an armoured target. It was found that the single largest variable was that of the test participants with all other variables such as handle size and shape having only slight effects on the magnitude of impact energy. The use of a finger guard or hilt was shown to increase the mean energy delivered to the target by approximately 5J compared to a handle having no guard. It was also found that the characteristics of energy delivery were strongly influenced by the position of the grip relative to this guard. This reinforces the conclusions of previous work (Horsfall et al., 1999; Chadwick et al., 1999) on the serial nature of momentum transfer during a stabbing impact.     

数字化成形加工技术的研究与应用

本文首先论述了数字成形加工技术的内涵及其技术路线,接着论述了数字化成形加工技术在国民经济中的地位与作用,最后介绍了轿车差速器锥齿轮和纺织机械中YJ2-142摇架手柄两个典型零件数字化成形加工技术的应用实例。