Section 74.—REVERSING GEAR.

For Reversing Gear of Steam Engines, see [Section 79].

[1290]. Reversible driving motion by open and crossed belts, with two loose and one fast pulleys.

[1291]. Reversible driving motion by single belt, two fast pulleys and one loose ditto and bevil gear, one bevil pinion having a sleeve to which its fast pulley is keyed, the other bevil pinion being keyed to the shaft.

[1292]. Reversible driving motion by single belt, with quick and slow motions; a modification of the last.

[1293]. By double clutch and bevil gear.

[1294]. Reversing friction cones or bevils.

[1295]. Three-wheel gear. The driving wheel A can be put into gear either with the driven wheel C or idle wheel B.

[1296]. Double clutch and spur gear reversing motion, with idle wheel.

[1297]. Reversing pinions, as used on the ordinary screw-cutting lathe. There are many varieties of this gear in use.

[1298]. Application of single belt gear to [No. 1296].

[1299]. Self-reversing gear, with one belt, two fast and one loose pulleys. The large spur wheel is driven from the bevil gear, and carries the weighted lever past the vertical position by a stop on the face-plate or disc, when it falls over and reverses the belt fork. See [No. 1026].

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[1300]. Self-reversing gear, as applied to planing machines. The stops can be set at any required distance apart, to alter the length of travel of the machine bed. This plan requires a heavy table to carry the belt across the loose pulley to the other fast pulley.

[1301]. Reversible belt-shifting hand gear.

[1302]. Right and left hand screw reversing traverse motion. Each lever has a half nut, which can be put in gear with the screw to drive either way. See also [No. 163].

[1303]. Best form of fast and loose pulleys for open and crossed belt reversing gear, as used in [No. 1290]; the fast pulley is rather larger in diameter than the two loose ones.

[1304]. Single-belt reversing pulleys, the reverse motion on the shaft being obtained by intercepting an idle wheel A between the epicycloidal wheel B and the shaft pinion C, the middle pulley being the loose one; the idle wheel is carried by a fixed bracket and pin.

Note.—Reversible motion can be obtained direct from any steam engine fitted with reversing motion. See Valve Motions, [No. 1436], &c.

Segment Reversing Gear, [No. 724].

Section 75.—ROTARY ENGINES, PUMPS, &c.

Nearly all rotary engines can be used either as motors, pumps, blowers, or meters, and most of the following typical devices have been applied to all four purposes. Most of them are reversible by simply reversing the direction of the motor fluid.

[1305]. Disston’s; used as a pressure blower.

[1306]. Root’s, blower and pump.

[1307]. Root’s.

[1308]. Mackenzie’s; may have one, two, or three vanes.

[1309]. Gould’s.

[1310]. Bagley and Sewall’s.

[1311]. Greindl’s rotary pump.

[1312], [1313], [1314], & [1315]. Varieties of intergeared piston rotary engines.

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[1316]. The small crescent-shaped piston revolves three times to one revolution of the three-armed piston.

[1317]. The hinged shutter is thrown out of the way each time the revolving arm passes it.

[1318]. Sliding shutter and cam piston device.

[1319] & [1320]. Varieties of the “Root” engine.

[1321]. The hinged vanes are closed upon the revolving piston as they pass the flat side of the casing.

[1322]. Has an eccentric piston and two hinged vanes.

[1323]. Eccentric piston and sliding diaphragm.

[1324]. Klein’s motion. The eccentric ring revolves in contact with the inner and outer casings, but is prevented from revolving on its axis by the fixed shutter and slot.

[1325]. Baker’s pressure blower.

[1326]. A modification of [No. 1323].

[1327]. The eccentric ring revolves on its centre, allowing the vanes to alternately project into the steam space as the wheel revolves.

[1328]. Ivory’s. An eccentric cam and two sliding shutters, with a central steam inlet.

[1329]. Mellor’s has a rocking vane oscillated by an eccentric piston carried round by a crank.

[1330]. Eccentric piston and two sliding vanes or steam stops.

[1331]. Differential rotary engine, with elliptical gear (see [Section 34]), or Stewart’s differential gear ([No. 554]) may be employed.

The “Tower” spherical engine is a well-known form of rotary engine. See Engineer, August 10th, 1883.

[1332]. An eccentric four-armed piston, with four rolling stoppers or packings.

[1333]. Mellor’s patent pump has a rocking vane or partition, with packing device which accommodates itself to the revolving oval piston.

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[1334]. Bisschop’s disc engine, with three or four cylinders, single acting, whose rams press alternately on the edge of the disc.

[1335]. Another form of disc engine, in which partitions (rising and falling vertically) form the steam stops.

[1336]. A modification of [1316].

[1337]. Rotary or centrifugal pump or fan, numerous varieties of which are in use. Many of the later forms, as Blackman’s and others, have the vanes fixed diagonally so as to propel the air at right angles to the plane of motion.