hide Matching Documents

The documents where this entity occurs most often are shown below. Click on a document to open it.

Document Max. Freq Min. Freq
Knight's Mechanical Encyclopedia (ed. Knight) 31 1 Browse Search
View all matching documents...

Your search returned 31 results in 8 document sections:

Knight's Mechanical Encyclopedia (ed. Knight), B. (search)
ding blocks. Ba-sane′. （Leather.) French tanned sheep-skins for bookbinding. Bawsin. Bascule. （French: see-saw.) A form of bailing-scoop used by Perronet at the Bridge of Orleans was worked by 20 men, 10 at each end. 600 motions were given to it per hour, and at each motion 4 cubic feet of water were raised 3 feetoscillate upon bearings on the summit of posts b, secured to a frame planted on the bottom of the river, pond, or inclosure to be drained. See bailing-scoop. Perronet's bascule. Bascule bridge. A counterpoise drawbridge which oscillates in a vertical plane; the inner portion descends into a pit, while the outer ascends of centuries. Benezet's tomb was in the crypt. About 1300, Issim, the Moorish king of Granada, erected a fine bridge at Cordova, across the Guadalquiver. Perronet mentions a stone bridge of three arches, one of which had a span of 159 feet 9 inches, at Verona, erected in 1354. Also a bridge with a stone arch 183.8 feet sp<
Knight's Mechanical Encyclopedia (ed. Knight), C. (search)
of wood, and having a plentiful lack of grease, make music, —such as it is. The French Engineer Perronet, who executed so many heavy public improvements during the last century (b. 1708; d. 1794)projects, original devices, fanciful ornamentation, graceful designs, and effective details. Perronet's carts. His ingenuity was manifested in the centering of his arches, coffer-dams, hydraulie soil and substrata. Fig. 1205, a is a center used at Westminster Bridge, an improvement on Perronet's system. Two timbers resting on the abutments incline and meet at the top, forming a large tr, 4 1/2 feet of the chain being wound round at each revolution. Chain-pump. Another of Perronet's chain-pumps (d), used at the bridge of Orleans, was worked by horse-power, twelve at a time bty referred to being accomplished by each. e is a section, and f an elevation, of another of Perronet's chapelets driven by a water-wheel. Chains. （Nautical.) Iron bars bolted to the sides
Knight's Mechanical Encyclopedia (ed. Knight), D. (search)
derland Harbor. The dredging-machine described by the Marquis of Worcester was a water-screw, but the bottom made of iron plate, spade-wise, which at the side of a boat emptieth the mud of a pond or raiseth gravel. The dredging-machine described in the Theatrum Instrumentorum et Machinarum, 1578, was rather an elevator than a dredger. The buckets were attached to endless chains, which passed over two drums, driven by winch-power. Laborers filled the buckets. The chapelet, used by Perronet and other French engineers in the last century for deepening channels and removing the mud from the interior of cofferdams in preparing foundations for bridges, was composed of three rollers, two of which touched the ground, and the other was placed upon an elevated timber scaffold, where the mud and silt were deposited. Round these rollers worked an endless chain formed of large links, to which were attached four or more sheet-iron scoops or scuttles, placed at regular distances. These
Knight's Mechanical Encyclopedia (ed. Knight), L. (search)
the roadway is nearly on a level with the water. It is also used in fortifications. The drawbridges (a) of Brussels were balanced by weights attached to chains passing over standards that stood immediately over the walls of the canal, and were braced and stayed by timbers and iron ties. The weight of the draws was borne by struts beneath, which were footed in set-offs in the faces of the masonry, and rested at their upper ends against jogs beneath the sill-timbers of the bridge. Perronet, the great French engineer, 1708 – 94, was the chief engineer of the Ponts et Chaussecs from 1747, and did more for the science of bridge-building than any of his contemporaries. He contrived a drawbridge (b) which had a short middle draw to allow the masts of vessels to pass when the headway beneath the bridge was sufficient for the hulls of the vessels. This middle section is hinged to one portion of the bridge and lifted by a chain and winch. Lifting-bridges. Lift′ing-gear.
Knight's Mechanical Encyclopedia (ed. Knight), N. (search)
haft, and operate the wheel upon which traverses a continuous rope furnished at intervals with jars or wooden buckets. The rope descends on one side with empty buckets and rises on the other side with full ones, which discharge into a chute leading to the cistern. These wheels are kept going day and night by relays of men and mules; in some cases being the joint property and care of the inhabitants of a whole village. Bucket-wheels. The great bucket-wheel (b, Fig. 3334) employed by Perronet at the construction of the Bridge of Neuilly, France, was 16 1/2 feet in diameter, 4 1/2 feet in width, and had 16 buckets and 118 cogs. The water-wheel by which the bucket-wheel was driven was 18 feet in diameter and had 128 cogs. The floatboards were 20 feet long, 3 feet wide, and were set at an angle of 15° with the radius. The lantern-wheels which acted as pinions to the large cog-wheels of the bucket-wheel and water-wheel were 4 feet in diameter and had 30 trundles. The axle of the
Knight's Mechanical Encyclopedia (ed. Knight), P. (search)
milar character, and were worked by rod-and-chain connection from the water-wheels in the river. The machines used by Belidor, Dueille, Desargues, Wahl, Morel, etc., are described by Cresy. Several of them are only peculiar in the modes of obtaining the reciprocating motion of the pistons from the rotation of the water-wheel. The chapelets used by the architect Perronet in pumping out the coffer-dams of his numerous bridges are described under chain-pump. The bucket-wheel used by Perronet is described under noria (which see). See also bascule; scoop-wheel; tympanum. The work of a man on a pump is estimated as equivalent to an effort of 17 1/4 pounds exerted through 2 1/2 feet in 1 second; or, 150 feet per minute = 9,000 feet per hour = 157,500 foot pounds or 70 foot tons per hour = 560 foot tons per day of 12 hours. Alarm-pump. The most favorable length of stroke on fire-engines is from 30 to 35 inches. Hydraulic-pressure pump. The power necessary is about
Knight's Mechanical Encyclopedia (ed. Knight), S. (search)
s; its monolithic character is said to be second only to the Church of St. Isaac's at St Petersburg, Russia. The derrick-crane was used on this building, and on the Capitol Extension also. Fig. 4648 represents a hanging scaffold contrived by Perronet for the workmen employed in dressing and pointing the masonry of the arches of the bridge at Orleans. It was suspended from a frame which straddled the parapet, and was rolled from place to place as required. The platform could be raised andf the skill of the architect and the faithfulness of the workmanship. If the piers have been solidly built on a firm foundation, and the arch-work accurately and strongly laid, there should be little or no subsidence. The bridge of Neuilly, by Perronet, settled two feet; Waterloo Bridge but five inches. The spandrels are afterward built up, the spaces between the arches filled in, the roadway and parapet completed. See arch; centering; bridge. The following table embodies some facts in re
Knight's Mechanical Encyclopedia (ed. Knight), T. (search)
of time this highly useful wheel, so much used in Oriental countries in raising water for irrigation, was improved by removing the exterior surface from which it derived its name, the buckets being made scoop-shaped. Such was the form used by Perronet, at Orleans Bridge, about 1750. In Fig. 6845, a is a section. and b an end elevation of this wheel. It had curved buckets, and raised the water 8 feet. Its effectiveness varied with the depth to which its circumference dipped into the water.: at each turn, 24 cells were emptied, each containing 1 1/2 cubic feet, giving, for the hour, 4.320 cubic feet of water raised 8 feet high; this was conveyed by the spiral buckets to an annular discharge-chamber around the axis of the wheel. Perronet's tympanum. The comparison of effectiveness was as follows :— Submergence.Revolution per hour.Cubic feet raised. 12 inches.1204,320 9 inches.1503,600 6 inches.1802,880 3 inches.1802,160 Tympanum. A modification of the tympanum h