2021-04-18 11:30:59

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ENGLISH "Have you got anything for me to eat?" I asked, not heeding his words.

"It mourns the lost liberty, the happiness, the peace, the brightness of her past prosperity which has vanished for a long season to come, it laments on account of the prisoners of war, the wounded, the dead.... And every morning the155 brilliant sun rises on the scene, the warm rays bathe town and country, both alike cruelly lashed by the frightful scourge.Another principle in planing machines which deserves notice is the manner of driving carriages or platens; this is usually performed by means of spur wheels and a rack. A rack movement is smooth enough, and effective enough so far as a mechanical connection between the driving gearing and a platen, but there is a difficulty met with from the torsion and elasticity of cross-shafts and a train of reducing gearing. In all other machines for metal cutting, it has been a studied object to have the supports for both the tools and the material as rigid as possible; but in the common type of planing machines, such as have rack and pinion movement, there is a controversion of this principle, inasmuch as a train of wheels and several cross-shafts constitute a very effective spring between the driving power and the point of cutting, a matter that is easily proved by planing across the teeth of a rack, or the threads of a screw, on a machine arranged with spur wheels and the ordinary reducing gearing. It is true the inertia of a platen is interposed and in a measure overcomes this elasticity, but in no degree that amounts to a remedy.

CHAPTER XII. BELTS FOR TRANSMITTING POWER.Netherland soldiers and inhabitants of the village bustled about along the opposite river-bank. I shouted as loudly as possible; and when at last I succeeded in drawing their attention, I made them understand that I wanted to be pulled across in the little boat, which in ordinary times served as a ferry. A short consultation took place now on the opposite side, after which a soldier, who clearly possessed a strong voice, came as near as possible to the waterside and, making a trumpet of his two hands, roared:

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However, the effect of these Austrian mortars was terrible enough. I could not form a correct opinion about them by the sound of the shot; and only those who were in the fort that was hit were able to realise the terrific results. Hence the interest of the report by an officer, who escaped after having been made a prisoner at Loncin. He told my colleague of De Tijd at Antwerp about it. After having related how, during nearly ten days, the fort had been defended heroically and reso64lutely, he gave the following description of the final struggle:At this point will occur one of those mechanical problems which requires what may be called logical solution. The valve must be moved by the drop; there is no other moving mechanism available; the valve and drop must besides be connected, to insure coincident action, yet the valve requires to move when the drop is still. Proceeding inductively, it is clear that a third agent must be introduced, some part moved by the drop, which will in turn move the valve, but this intermediate agent so arranged that it may continue to move after the hammer-drop has stopped.

"Sister," I said then, "if you will only ask S?ur Eulalie to come to this gate she will recognise me, of course?"Forging plant consists of rolling mills, trip-hammers, steam-hammers, drops, and punches, with furnaces, hearths, and blowing apparatus for heating. A general characteristic of all forging machines is that of a great force acting throughout a short distance. Very few machines, except the largest hammers, exceed a half-inch of working range, and in average operations not one-tenth of an inch.

So at last the lock of the heavy door screeched, and I was admitted. I noticed that about a score of sisters had gathered behind the gate and were anxiously discussing the "strange occurrence." My meeting with S?ur Eulalie, however, was so cordial that the good nuns lost all anxiety, and I was taken inside accompanied by nearly all the inmates of the convent.(1.) Why cannot the regular working drawings of a machine be employed to construct patterns by?(2.) What should determine the quality or durability of patterns?(3.) How can the arrangement of patterns affect certain parts of a casting?(4.) What means can be employed to avoid inherent strain in castings?(5.) Why is the top of a casting less sound than the bottom or drag side?(6.) What are cores employed for?(7.) What is meant by venting a mould?(8.) Explain the difference between green and dry sand mouldings.(9.) Why is sand employed for moulds?(10.) What generally causes the disarrangement of cores in casting?(11.) Why are castings often sprung or crooked?(12.) What should determine the amount of draught given to patterns?(13.) What are the means generally adopted to avoid cooling strains in castings?7. The effect of pneumatic machinery in reducing insurance rates and danger of fire.

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"Return that knife at once!"An apprentice may get a clear idea of this venting process by inspecting tubular core barrels, such as are employed in moulding pipes or hollow columns, or by examining ordinary cores about a foundry. Provision of some kind to 'carry off the vent,' as it is termed by moulders, will be found in every case. The venting of moulds is even more important than venting cores, because core vents only carry off gas generated within the core itself, while the gas from its exterior surface, and from the whole mould, has to find means of escaping rapidly from the flasks when the hot metal enters.The importance of standard dimensions, and the effect which a system of gauging may have in the construction of machines, will be a matter of some difficulty for a learner to understand. The interchangeability of parts, which is the immediate object in employing gauges, is plain enough, and some of the advantages at once apparent, yet the ultimate effects of such a system extend much farther than will at first be supposed.

Materials consumed in an engineering establishment consist mainly of iron, fuel, sand, and lumber. These articles, or their products, during the processes of manipulation, are continually approaching the erecting shop, from which finished machinery [72] is sent out after its completion. This constitutes the erecting shop, as a kind of focal centre of a works, which should be the base of a general plan of arrangement. This established, and the foundry, smithy, finishing, and pattern shops regarded as feeding departments to the erecting shop, it follows that the connections between the erecting shop and other departments should be as short as possible, and such as to allow free passage for material and ready communication between managers and workmen in the different rooms. These conditions would suggest a central room for erecting, with the various departments for casting, forging, and finishing, radiating from the erecting shop like the spokes of a wheel, or, what is nearly the same, branching off at right angles on either side and at one end of a hollow square, leaving the fourth side of the erecting room to front on a street or road, permitting free exit for machinery when completed.

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Apr-18 11:30:59