Effect of belt transport speed and other factors on belt mistracking

Rubber rollers and conveyor belts transport flexible sheet-type media. With high-speed belt transporting systems such as mail sorters, demand for an increase in speed may cause the belt to come off. Therefore, we have examined the effects of belt transport speed and other factors that may cause belt mistracking for a basic belt conveyor system, consisting of one flat belt and two crown-face rollers. Experiments were conducted and we have formulated an experimental expression of the amount of belt mistracking using the roller misalignment parameters. As for transport speed, a speed increase did not enlarge belt mistracking. This tendency was explained by applying the cornering force of automotive engineering. In parallel, simulation was conducted using commercial motion system analysis software. The qualitative tendencies of the belt mistracking from simulation and experiment were in good agreement and factorial effects were clarified for ten parameters. Quantitatively, when axial load on rollers and other parameters were made equal, the belt mistracking according to simulation was generally in agreement with the experimental value.     

Color registration error reduction method compensating the influence of belt thickness variation in electrophotographic process

This paper proposes a new belt drive control method for reducing a belt velocity-fluctuation that is caused by a belt thickness-variation in the circumferential direction. A belt driving system performs feedback control with a rotary encoder-output mounted on a driven roller. This proposed method correct the reference value of the feedback control for the purpose of the belt velocity regulation. The correction includes two steps. The first step acquires the encoder-output of the driven roller and calculates the rotational angular velocity-fluctuation with one cycle of the belt rotation. The second step converts from the velocity-fluctuation to the correction value of the feedback reference. The correction value cancels a detection error of the driven roller caused by the belt thickness-variation. After these steps, the belt driving system controls the belt velocity as compensating the belt velocity-fluctuation. Experimental result showed the significant fluctuation reduction on a typical tandem-engine printer.     

The effects of a back belt on posture, strength, and spinal compressive force during static lift exertions

The experiment reported in this paper evaluated changes in lifting posture, static lifting strength and the estimated L3/L4 spinal compressive force resulting from the use of an abdominal support or ‘back' belt. Torso posture and maximum static lift strength were measured for eight male and eight female subjects using symmetric and asymmetric hand positions at calf height and elbow height. Body posture, and hand forces were also used as input to a three-dimensional static biomechanical model of the torso used to estimate L3/L4 spinal compressive force. The results showed axial twist of the torso to be significantly lower for calf height asymmetric exertions when the abdominal support belt was worn. The measured reduction in axial twist was approximately four degrees. No other significant effects on posture due to the support belt were found. Static lift strength was not significantly increased or reduced when the support belt was used. Predicted spinal compressive force was significantly lower when a support belt was worn (2840 N compared to 3125 N when the belt was not worn). Overall, the results of the experiment demonstrate a very limited benefit to the user of abdominal support belts, primarily due to reduced or restricted motion during asymmetric and lower-level lifts.Relevance to industryBack belts are commonly used in industry to mitigate manual materials handling hazards. One assumption often made by those recommending the use of back belts is that they substantially reduce the bending and twisting of the torso. The experiment reported in this paper tests this assumption and provides information on the utility of back belts.     

堆钢预判在推拉式酸洗机组的研究与应用

推拉式酸洗机组穿带时在一定张力下带材与入口转向辊同步运行。在此基础上通过间接测距法，实现带头跟踪，时时、准确的判断带头所在位置。根据钢带通过挤干辊，其电机力矩与电流将发生变化这一现象，作一比较判断。当枪洲到带头到达挤十辊时，若该挤干辊电流急剧上升，则判定为穿带正常，若电流无明显上升，则判定带材在该挤干辊之前堆钢，完成一次堆钢预判。     

Computerized tolerance analysis of disk cam mechanisms with a roller follower

The tolerance analysis is one of the key elements of design and manufacturing of cam mechanisms. This paper presents a computerized method for analyzing the tolerances in disk cam mechanisms with a roller follower. By employing the concept of simulated higher-pair contact analysis, the kinematic deviation of the follower motion arising from the tolerance amount of each design parameter can be determined numerically. The offset translating roller follower and the oscillating roller follower cases are given to illustrate the proposed method. The tolerance analysis results show that, owing to the combined effects of various design parameters, the position accuracy of the follower motion may degrade considerably. But, the tolerance amounts of the design parameters may also have a compensating effect to enhance the relative accuracy of the follower motion between its high and low dwell positions. Hence, it is possible to find the optimal tolerance combination for balancing the kinematic accuracy and the tolerance amounts of disk cam mechanisms with a roller follower.     

轻型带式输送机及防逆风装置的研制与应用

针对现有普通带式输送机普遍存在故障点多、成本高、耗电量大、不易铺设和安装等缺陷,结合井下环境特点,研制了一种轻型带式输送机。该轻型带式输送机将原普通带式输送机传动部位改造为以卸载滚筒兼作电动机、联轴器、减速器、传动滚筒的传动装置,极大简化了普通带式输送机传动装置,实现了掘进工作面的集中控制;并利用手动蜗轮张紧装置替代了原有蜗轮、蜗杆张紧装置,使该轻型带式输送机具备结构简单、重量轻、安装维护方便等特点;同时实现了轻型带式输送机与防逆风装置的联锁,能有效防止掘进工作面原煤运输时风量流失,防止风流逆转和瓦斯进入进风流。     

煤矿胶带输送机防纵撕事故的研究

分析了煤矿胶带输送机发生纵撕事故的主要原因,即锚杆、钎子等硬件,矸石或托辊等将胶带撕裂;提出了加强巡检、尽量使用带防撕裂网的胶带、安设防纵撕保护传感器等预防胶带运输机纵撕事故的方法。文章对预防胶带运输机纵撕事故具有一定的指导作用。     

卸载过程的物料运动研究

在物料输送中卸载过程的物料运动是非常复杂的。利用运动学原理分析了物料的受力情况,解析了水平输送、倾斜向上输送和倾斜向下输送3种情况时临界状态发生的条件,确定了输送带以不同角度趋入滚筒时物料被抛出的始点位置和切线角,研究了物料在输送带上的运动状况并得出结论,最后建立卸料轨迹方程,用计算机实现了轨迹线的绘制。     

A method for modelling contact between circular and non-circular shapes with variable radii of curvature and its application in planar mechanical systems

Contact impact has been widely found in the operation of various mechanical systems. These mechanical systems include the type of mechanism typically characterised by circular–non-circular geometric contact. They consist of the mechanisms of the cam with a roller follower, a Geneva wheel with intermittent motion, a cog belt drive with circular-arc teeth, a cycloidal-pin wheel gear, and a roller chain drive. For the two components in contact, one component needs to have an ideal circular shape, while the other is characterised by its non-circular geometry, that is, the contact shape may present varying radii of curvature. Taking this kind of contact mechanical system as a research object, this work proposes a general method for analysing the problems concerning contact impact on this circular–non-circular geometry. This method discretises continuous non-circular geometries to acquire a series of discrete points. Then, the contact areas of components are determined by repeatedly judging the relationships between the positions for various discrete points and the circular geometric centres thereof. In the contact areas, the maximum depth of the contact is measured, and the positions of the contact points between components, in a direction along the maximum contact depth, are determined. Finally, the normal contact force and tangential friction force between contacting components are established at the contact points. This method can be applied to analyse the problems concerning single contact and multi-point contact among various contact components. To verify the validity of this method, this work takes an offset translational roller follower disc cam mechanism (with a single contact) and a cycloidal-pin wheel gear mechanism (with multi-point contact) as examples and investigates the dynamic characteristics of the contact impact for the aforementioned mechanical systems, respectively.     

波纹辊轧机辊系主共振时滞反馈控制

金属复合板波纹辊轧制成形是一项变革技术,在复合板轧制成形的过程中,轧制界面的非线性阻尼以及上下波纹辊之间的非线性刚度都可能导致主共振的发生,造成辊缝的波动.考虑了波纹辊轧机波纹界面间的非线性阻尼和非线性刚度,建立了波纹辊轧机两自由度垂直非线性数学模型.利用奇异值理论和相平面法讨论了波纹辊轧机辊系自治下的稳定性,运用多尺度法求解了波纹辊轧机辊系在波纹界面激励下主共振的解析近似解和幅频特性方程.分析了非线性刚度系数、非线性阻尼系数、系统阻尼系数、轧制力的幅值等参数对主共振的影响.设计了线性和非线性复合作用的时滞反馈控制器来对波纹辊系的主共振进行控制,并且通过数值仿真验证了控制器设计的正确性和可行性.     

Skew simulation of a paper transferred by rubber rollers in printers

A skew of a paper transferred by rubber rollers in printers is simulated by FEM software. Effects of an imbalance of preload, an imbalance distribution of coefficient of friction and a front tension on the paper skew are investigated and how to determine the skew direction are shown. A simulation model is composed of a feed roller, a preload roller and a paper. The feed roller is rotated forcibly by a certain degree at every calculation step and a deformation, displacement and strain of the paper and rollers are calculated. A series of calculation results is shown as a motion simulation. The results show that the paper skews to the smaller preload side, to the smaller coefficient of friction side, or to the opposite side of the front tension. Further, effects of a skew prevention guide plate is simulated.     

A roller embossing process for rapid fabrication of microlens arrays on glass substrates

This paper reports an innovative technique for rapid fabrication of polymeric microlens arrays based on UV roller embossing process. In this method, a thin flat mold is fabricated by electroforming of nickel against a microlens master. The thin Ni mold with microlens cavities is then wrapped onto cylinder to form the roller. During rolling operation, the roller pressing and dragging the UV-curable photopolymer layer on the glass substrate through the rolling zone, the microlens array is formed. At the same time, the microlens array is cured by the UV light radiation while traveling through the rolling zone. The technique can be developed to an effective roll-to-roll process at room temperature and with low pressure. In this study, a roller embossing facility with UV exposure capacity has been designed, constructed and tested. Under the proper processing conditions, the 100×100 arrays of polymeric microlens, with a diameter of 100 μm, a pitch of 200 μm and a sag height of 21 μm can be successfully fabricated.     

烟片复烤机流量恒定控制的设计应用

为了解决目前烤片机入口流量未知,对烤片机性能指标控制不理想的问题。对以往烤片线工艺路径及控制方式进行了改进：在仓式喂料机与烤片机之间增加了一台控制型电子皮带秤。通过控制电子皮带秤皮带转速与仓式喂料机陡角带转速,实现了烤片机入口流量恒定控制的目的,经过设备长时间的稳定运行表明;该控制方式是成功的,烤片机可以按照设定流量稳定的运行,为复烤厂的工作进度及计划安排提供了一个可靠的依据,提升了烤片机的控制性能。     

浅析煤矿带式输送机“六大保护”

结合济宁三号煤矿带式输送机"六大保护"的现场使用情况,分别介绍了驱动滚筒防滑保护、堆煤保护、防跑偏保护、温度保护、烟雾保护和超温洒水保护这"六大保护"的安装位置、安装方式、动作原理、作用及重要性,指出应结合煤矿的实际情况对"六大保护"合理选型、安装及使用,且需要配合其它类型的保护,以保证带式输送机正常运行。     

矿用胶带机集中控制系统的研制

介绍了由多台智能综保仪构成的矿用胶带机集中控制系统,每台综保仪能实现各胶带机胶带的高低速度、滚筒温度、机头烟雾、CO浓度、堆煤以及跑偏等各种保护功能,还兼有与前后胶带机智能综保仪通信的功能,使整个系统具有逆煤流启动、顺煤流延时停车功能。     

Will it reach the top? Prediction in the mechanics world

We describe an extension of a mechanics problem solving program to the set of “roller coaster” problems, i.e. problems about the motion of a particle on a complex path. The reasoning strategy adopted by the program is described and compared to earlier work in this domain. Conclusions are drawn about the representation of motion and prediction. Questions are raised about Frames and Multiple Representations.     

金属矿山井下胶带运输控制系统的设计与应用

针对某金属矿山原有的胶带运输系统采用继电器控制而存在可靠性差的问题,提出了一种基于ControlLogix技术的胶带运输控制系统的改造方案。该系统采用ControlLogix技术实现胶带运输系统传动和运动控制的任意组合;采用光纤通信和网络冗余技术实现设备组态、信息采集以及远程故障诊断功能;采用电子过载继电器实现对电动机的保护;采用可视化人机界面实现对胶带运输系统工作状态的实时监控。实际应用表明,该系统提升了胶带运输系统的可靠性。     

基于反求技术的摆动从动件空间凸轮CAD

由于测绘点的实际接触点在理论上存在差异,摆动从动件空间凸轮机构的反求问题目前仍未获取很好解决,本文在空间凸轮反求ＣＡＤ中,担子 利用廓面测绘数据根据共轭面面原理反求出从动件运动规律,再利用该运动规律和有关结构参数重新解析设计出廓面的新方法。文中对反求方法和测绘数据进行了分析;提出了理论廓面、实际廓面的相关性质;在此基础上,利用共轭曲面原理导出了从动件运动反求的非线性规划数学模型,给出了算法。本文的     

平带系统非线性振动实验研究

为研究传动带在运转过程中的非线性振动问题，建立了一套平带传动实验系统．通过多功能控制卡输出的电压模拟量控制伺服电机控制器驱动电机转动，进而产生带的传动．利刖激光位移传感器及L．K—Navigator软件采集并保存带传动过程中的横向振动位移．选取平带系统在匀速转动和有激励扰动的情况下进行多组实验，实验数据的分析证明带在传动过程中存在周期、倍周期、混沌等非线性现象．