共查询到20条相似文献，搜索用时 593 毫秒
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《林业机械与木工设备》1998,(2)
英研制成不产生木屑的电锯该新型电锯工作时，锯片本身不移动，它是利用滚筒将木料以极快的速度从锯上推过的。因为这种锯木方式推力强大，速度比普通电锯快得多，所以就没有木屑产生。英研制成不产生木屑的电锯... 相似文献
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娄茂达 《林业机械与木工设备》1988,(5)
建国三十多年来,我国先后从苏联、德国、加拿大、美国、日本等9个国家23个厂家进口油、电锯88种1294台,其中油锯1263台,电锯31台,累计金额180万元。通过进口油、电锯,不但解决了木材生产之需,而且在消化吸收的基础上先后仿制和研制成功3种国产电锯和9种油锯;建立了3个具有相当规模的油锯制造厂和有关的油锯配件生产厂,形成一支具有 相似文献
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兰凤崇 《林业机械与木工设备》1989,(2):46-49
以人体工程学的研究方法,着重探讨了手提式林业机械的隔振效果及操作者受振的评价方法,并对我国手提式林业机械的手受振动标准和如何保障操作者的健康提出了一些意见。 相似文献
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Summary The band saw blade vibration under non-moving and moving conditions has been experimentally studied for band saw blades unfitted with saw tension and back crown, fitted only with saw tension, and only with back crown. The lateral natural frequency of a band saw blade was found to decrease by fitting saw tension in a saw blade, but there was little or no effect for blades having only back crown. The torsional natural frequency of a band saw blade increased by fitting saw tension in a saw blade, but again there was little or no effect of fitting back crown in a blade. The lateral natural frequency decreased by tilting the upper wheel for the band saw blades investigated. On the contrary, when the upper wheel was tilted the torsional natural frequency increased for an untensioned blade with no back crown, and blades fitted only with back crown, however, there was little or no effect for a band saw blade fitted only with tension. The lateral and torsional natural frequencies significantly affected the over all self-excited displacement vibration of band saw blades. However, the displacement vibration due to the frequency of the number of wheel rotation affected significantly the over all self-excited displacement vibration of a band saw blade fitted with excessive back crown.The authors wish to express their appreciation to Dr. F. E. Dickinson, Univ. of California, Berkeley, Calif., for an excellent job of revising the grammar and his valuable suggestions. This investigation was supported in part by Grants in Aid for Scientific Research from the Ministry of Education, JapanMembers of the Faculty of Forestry, Shimane Univ., Matsue, JapanMember of Shimane Prefecture Forestry Experiment Station, Shimane, Japan 相似文献
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张占宽 《林业机械与木工设备》2005,33(6):13-15
将未适张、辊压适张、锤击适张圆锯片装在不同直径的夹盘上，施以相同的夹紧力后进行振动模态分析。实验证明，不论是未适张圆锯片，还是辊压和锤击适张圆锯片，随着夹盘增大，锯片各阶固有频率都有不同程度的提高，其中辊压适张圆锯片二阶振动模态的固有频率没有增加或只有少量增加，锤击适张圆锯片四阶以上振动模态的固有频率有显著增加。 相似文献
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Shrub encroachment has become a problem in many rangeland systems across the United States due to a reduction in the disturbances, primarily fire, which historically maintained them. The shrub saw palmetto (Serenoa repens) has become abundant in many habitats of the southeastern Coastal Plain, including Florida. When fire regimes are altered or fires are suppressed, this species can proliferate leading to significant changes in the ecosystem, particularly the herbaceous vegetation. Prescribed burning and roller chopping are management activities often used to control saw palmetto. However, little is known about the effects these treatments have on this shrub, particularly when applied in different seasons. We compared the seasonal effects of prescribed burning, roller chopping, and combinations of the two on saw palmetto. The effects of treatments on saw palmetto were assessed using a paired-sample approach, where saw palmetto height, cover, and density were compared between sampling locations randomly located within treated (e.g., burned) and untreated areas. Dormant season burning had no effect on saw palmetto density and height and only temporarily reduced cover, with rapid regrowth occurring the first year post-treatment. Growing season burning also had no effect on saw palmetto density. However, saw palmetto cover was lower on growing season burn compared to control sites the first year post-treatment and height the first and second year post-treatment. The combination of burning and roller chopping, despite having no effect on saw palmetto density, did result in lower saw palmetto height compared to controls the first and second year post-treatment. The effect of roller chopping/burning on saw palmetto cover depended on season and year. Saw palmetto cover and height were lower on dormant and growing season roller chop than control sites the first and second year post-treatment, but only growing season roller chopping had an effect on saw palmetto density. The single application of a dormant or growing season burn is not recommended for control of high-density saw palmetto, however, it may be suitable to maintain areas where saw palmetto levels are low and proliferation of the species is not a threat. Dormant and growing season roller chopping showed the greatest potential for rapid saw palmetto control. Growing season roller chopping is recommended if significant reductions in saw palmetto density are desired. 相似文献
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ABSTRACTThis paper investigates the effect of rotation speed and vibration response of a circular saw on the sawing process of Douglas-fir wood. An idling test was conducted on a guided circular saw to determine its stable operation speeds and vibration behavior. Short-time Fourier transform analysis was performed on saw idling test data, and variation of excited frequencies of the blade as a function of rotation speed was obtained. The saw blade critical speeds and the rotation speeds that correspond to saw flutter instability were identified. Then experimental cutting tests were conducted at different cutting conditions and the effect of rotation speed and saw vibration response on cutting power consumption and sawing accuracy was investigated. The results showed that conducting a saw idling test and vibration response analysis can identify the saw critical and flutter speeds, which is essential for identifying the optimum rotation speed of circular saw. There was a significant increase in power consumption when cutting at super-critical and super-flutter speed. The effect of rotation speed on sawing accuracy is complex and nonlinear. This effect interacts with feed speed, which makes it difficult to generalize sawing accuracy versus rotation speed in the circular sawing process. 相似文献
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带锯机锯轮转速、锯条摆动与锯解精度的试验研究 总被引：2，自引：0，他引：2
基于对木工带锯机加工特性的研究需要,本文在MJ397型高速木工带锯机的锯条张紧力和进给速度恒定的情况下,通过实测锯机工作台和锯条结构系统的固有频率、同条件下锯割杉木试材时的锯条横向摆动量、变频器调节锯轮转速和锯材表面粗糙度等,分析锯轮转速、锯条横向摆动量与锯解精度的关系,为优化国产带锯机锯割稳定性等设计工作提供依据. 相似文献
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Operation safety during sawing operations as well as dimensional accuracy and surface roughness depend on circular saw dynamic
features among other factors such as circular saw blade accuracy and static/dynamic properties of the machine tool. Manufacturers
of saw blades have an obligation to mark tools with a value stating the maximum allowed rotational speed for each saw. However,
in some cases the value indicated on the saw corresponds to the critical rotational speed or is dangerously close to this
critical value. Saw operation at the critical rotational speed is inadvisable and may result in serious injury or depreciation
of product quality. This report outlines a simple methodology for evaluation of circular saw critical rotational speed. The
assessment was conducted with a camera vision technique on the basis of an impulse test. Results are compared with theoretically
calculated critical rotational speeds and the marks on saw blades. 相似文献
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文章论述了一种圆锯片适张状态的检测方法及实现的系统 .该方法采用锯片适张前后固有频率的变化幅度 ,锯片单点加载情况下一定半径圆周上的横向变形量和端面圆跳动三个特征参量 ,表述一个锯片的适张程度、适张均匀性和平整性 .应用计算机控制的检测系统 ,经过对大量不同规格木工锯片和大型金刚石锯片的检测 ,结果表明该方法是切实可行的 相似文献
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