Spons' Dictionary of Engineering, Civil, Mechanical, Military, and Naval, Volumen7Edward Spon, Oliver Byrne, Ernest Spon, Francis N. Spon E. & F.N. Spon, 1874 |
Otras ediciones - Ver todas
Términos y frases comunes
acid angle arrangement ashlar attached axis axle beam bearing blow boiler bolts bottom buckets buddle carried cast cast-iron centre circular connected connecting rod crank cubic curve cylinder depth diameter disc distance driving edge engine equal extrados fixed flange force frame friction gear girder horizontal inch joints latter leading wheels length lever load longitudinal lower machine manganese material means mercury metal metalloids meter mètre obtained ordinary particles passes pile pinion pipe piston placed plates pressure pulley pump quantity rail Railway ratchet-wheel revolving rollers rotary motion rotation screw semolina shaft sheet shown in Fig side sleepers slide slot soffit SPAN specific gravity spindle spur-gear square steam steel stone strain strength strength of materials stroke stuffing box surface thickness timber tons trailing wheels transverse upper valve velocity vertical weight wheel wrought iron
Pasajes populares
Página 2668 - ... should be simple in construction, and not liable to get out of order under the rough usage of the men by whom it has to be worked.
Página 2371 - ... the breadth at least equal to the thickness, and seldom greater than twice this dimension, and to limit the length to within three times the thickness. When the breadth or the length is considerable, in comparison with the thickness, there is danger that the block may break, if any unequal settling, or unequal pressure should take place. As to the absolute dimensions, the thickness is generally...
Página 2371 - For the coping and top courses of a wall, the same objections do not apply to excess in length : but this excess may, on the contrary, prove favorable ; because the number of top joints being thus diminished, the mass beneath the coping will be better protected, being exposed only at the joints, which cannot be made water-tight, owing to the mortar being crushed by the expansion of the blocks in warm weather, and, when they contract, being •washed out by the rain.
Página 2433 - Two worm-wheels of equal diameter, but one having one tooth more than the other, both in gear with the same worm. Suppose the first wheel has 100 teeth and the second 101, one wheel will gain one revolution over the other during the passage of 100 x 101 teeth of either wheel across the plane of centers, or during 10,100 revolutions of the worm.
Página 2436 - The wheel to the right is the "going-wheel," and that to the left the "striking-wheel." P is a pulley fixed to the great wheel of the going part, and roughened, to prevent a rope or chain hung over it from slipping. A similar pulley rides on another arbor, p, which may be the arbor of the great wheel of the striking part, and attached by a ratchet and click to that wheel, or to clock-frame, if there is no striking part.
Página 2373 - ... differs from coursed rubble in not being built in courses ; but in other respects the same rules are to be observed. The resistance of common rubble to crushing is not much greater than that of the mortar which it contains; it ia therefore not to be used where strength is required, unless built with strong hydraulic mortar.
Página 2458 - Chlorine removes all other matter from metals when the latter are in a state of fusion. Carbon, sulphur, and phosphorus are drawn off by it, and, if the heat is continued, the chlorine itself escapes with a portion of the metals, but only when a minute proportion is present ; it is thus a powerful element in the purification of metals. Lead smelted from chlorides is purer than from oxides and sulphurets, and its proper application to smelting and refining purposes has a most beneficial influence.
Página 2373 - ... mortar or with rubbish where pieces of stone ought to be inserted, and that each stone is laid flat, and on its natural bed. Care must be taken that the headers or bond-stones are really what they profess to be, and not thin stones set on edge at the face of the wall.
Página 2371 - The surfaces of the other set should be perpendicular to the beds, and at the same time perpendicular to the face, or to the back of the wall, according to the position of the stones in the mass ; two essential points will thus be attained ; the angles of the blocks at the top and bottom of the course, and at the face or back, will be right angles, and the block will therefore be as strong as the nature of the stone will admit. The greater the accuracy of the dressing, the more readily can these...
Página 2623 - York, the centre piles are subjected to a pressure varying from 10 to 20 tons. Altogether there were seven thousand piles driven, in rows 2 ft. 6 in. apart, and at transverse distances of 3 ft. from centre to centre. The main piles were round spruce spars, very straight, from 25 to 45 ft. in length, having an average length of 32 ft. They were not less than 7 in. in diameter at the smaller end, and on an average 14 in. in diameter at the larger end. The heads of the piles were always protected in...