(ForAdditionsseepages 245-335.)
1. Rope pulley anchor—a car which grips by sinking its wheels in the soil; employed for ploughing tackle.
2. Anchor plate—buried in the ground below a mass of masonry—for attaching guys, tie rods, &c. Sometimes a frame, or plate, laid on the ground and ballasted, is the method used.
3. Screw mooring,screwed into the ground.
4. Heavy stonesunk in the ground and having a ring attached; or a mass of concrete, similarly placed, used for guy ropes, tie rods, and foundation bolt attachments.
5. Grapnel.
6. Mushroom anchor.
7. Double fluke anchor.
8. Martin’s patent anchor,with swivelling flukes. Several other patent anchors are modifications of this.
Stakes, with or without flanges, vertical or horizontal, are sometimes employed, the flanges taking the cross strain of the ties, &c. Fencing posts, gate posts, tree stakes, and tennis poles are of this class.
For adjustment by Screws, seeSection 78, and by Wedges, seeSection 36, These are the commonest appliances employed. For Cams also, seeSection 9. For adjusting Pedestal Brasses, seeSection 46.
For adjustments by keys, cotters, &c., seeSection 37. See alsoNos. 251,269, and297.
9. Split cone sleeves and set screw adjustmentfor a revolving standard, or similar detail, where there is much wear or great accuracy is required in the revolving bearing.
10. Centre-line adjustmentfor lathe headstocks, &c.
11. Variable curve adjustment;used in compass planes, instruments for drawing arcs of circles, &c.
12. Vertical shaft footstep adjustment;employed on millstones, horizontal grinding mills, &c., to regulate the space between the grinding surfaces. SeeNo. 261.
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13. Side screw adjustmentfor injectors, jet pumps, &c.
14. Levelling adjustment;can be used with either 3 or 4 screws: for telescope and level stands, theodolites, &c.
15. Horizontal central adjustmentfor footsteps, &c.
16. Slotted link and lock nutfor adjusting angle of a lever.
17. Disc and ringwith partial angular adjustment by a screw and nut; used for screwing dies, self-centering chucks, &c. The nut and bearing of the screw have allowance for swivelling.
18. Pin and hole adjustmentfor a lever or similar detail.
19. Wedge bearingfor locomotive horn plate guides, slide bars, and similar parts subject to wear.
20. Right and left-hand screw and wedge adjustmentfor roller bearings, &c.
21. Adjustment for wearused on engine crossheads to take up the wear of the working faces.
Adjustable Crane Balance Weights,Section 18.
AdjustableV-guides,Nos. 700and704.
Materials employed are:—Leather, cotton, guttapercha, indiarubber, canvas, camel-hair, catgut, flat wire or hemp rope, steel bands, flat chains, &c.
22. Ordinary belt pulley,“crowned†on face to retain the belt on the centre of the pulley.
23. Double-flanged pulley,flat on face, sometimes “crowned,†asNo. 22.
24. Single-flanged pulleyfor horizontal driving.
25. Open belt gear;runs best as shown, with the slack half of the belt at top.
26. Crossed beltto reverse motion on the driven shaft. Also to obtain more grip for the belt than with open belts.
27. Mode of drivingwhen the shafts are at right angles to one another.
28. Mode of drivingwith shafts at an obtuse angle, sometimes used instead of bevel wheels.
29. Arrangement adopted when the pulleys cannot be got in linewith one another, or the shafts are too close together to drive well direct. Short belts seldom work well.
Belts are frequently arranged to pass under and over several pulleys so as to drive several shafts by one belt.
For reversing by belt gear, seeSection 74. Gut bands (round) are worked overV-grooved pulleys; see Rope Gearing,Section 66. Belts may be kept tight by tightening pulleys, seeNo. 1207. For round belts, see Rope Gearing,Section 66.V-belts are occasionally used, formed of thicknesses of leather riveted together, cut to aV-section, and worked overV-grooved pulleys.
30. Universal hinge.The arm can be fixed in any required position by tightening the gland. Useful for stands for articles to be exhibited in any position, telescopes, &c.
31. Pipe joint,with similar capabilities.
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32.Same asNo. 16, but with screwed gland. If used without the arm, it forms the ordinary ball castor.
33&34. Dr. Hooke’s universal joint.See application,No. 292. See alsoNos. 1359and732.
Gas pendants are suspended with a joint similar toNo. 31, but the ball, having only a restricted angular motion, is cut down to a segment only.
To retard or arrest motion (revolving or rectilinear).
35. Strap and lever brake.The strap is usually faced with wood or leather, but sometimes is used without either. Wood is liable to become noisy. Leather gives the best grip. Iron upon iron, or wood upon iron is not safe if liable to become oily or wet.
36. Block and lever brake.Wood or cast-iron blocks are used.
37. Compound block and lever brake;avoids putting cross strain on the shaft—used on winding engines, &c.
38. Internal toggle brake,employed for friction clutches. SeeSection 15. The inner ring is turned to fit loosely inside the outer ring and split, the toggles being arranged as shown to expand the ring till it is locked to the outer ring.
39&40. Double block and lever brakeon wheel rim grips the wheel rim between the lever stocks or jaws. The strains are self-contained.
41. Disc brake;considerable end pressure is required with this form, and must be arranged for in the bearings of the shaft.
42. Compound disc brake.Several discs may be employed, sliding on feathers on the shaft.
43. Fan brake;may be run openly in air, or enclosed in a drum with water, oil, or other liquid. (See Allen’s patent Governor, &c.)
44. Spring brake,acting on a small grooved pulley; for light purposes.
45. Rope brake or grip,with toggle motion, and screw for relieving.
46. Rope brake:grips by the angular distance between the jaw centres becoming less as the lever end falls.
47. Rope brake;with cam lever gripping motion.
48. Eccentric action lever and block brake.The eccentric is fixed to the brake lever. This plan also avoids cross strain on the shaft.
49. Strap and screw brake.
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50,51, &52. Three forms of car brakes.See also the common “skid†or cart brake.
53. Combined strap and lever brake.(Fielden’s.)
54. Shaft grip, or brake.
55. Centrifugal brake, or clutch.The weight segments are driven into contact with the ring by centrifugal force. Springs may be used to return them out of action.
56. Three-segment compound brake:grips the wheel all round.
57. Compound bar brake,with right and left hand screw grip levers, used for heavy gun compressors.
58. Compound ring brake,on similar principle toNo. 57. See remarks toNo. 41.
59. Wedge and split ring,used for internal brake ring or clutch, in a similar way toNo. 38.
60. Hollow drums, with radial pockets,half filled with loose material, or water, mercury, &c., which retard the motion of the drum by the weight and friction of the loose material.
An hydraulic cylinder and piston is frequently used as a brake or retarding device for reciprocating motion, the water passing from one side of the piston to the other, through an adjustable valve. Friction brakes are employed as dynamometers to indicate the power given off or absorbed by any piece of machinery. Automatic brakes (seeSections 15and69) are used for hoisting machinery, &c.
Brushes, formed of stiff bristles or wire, are used as a retarding device for circular or rectilinear motion.
Vessels or containers of every conceivable shape have been used as boilers. Many of the older types are now obsolete, but the following are these most commonlyused:—
61. Ordinary centre flue boiler.Sometimes the centre flue is surrounded with tubes, asNo. 65.
62. Vertical multitubular.
63. Vertical boiler,with diagonal tubes and smoke boxes.
64. Vertical return-flue.
65. “Pot†boiler.
66. “Field†boiler;with suspended tubes and internal circulating tubes.
67. Vertical egg-end boiler;with spiral flue. Large vertical boilers sometimes have cross flues, or large tubes.
68. Portable “loco-typeâ€multitubular.
69. Fixed return-tube.
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70. Fixed “loco-typeâ€multitubular; a favorite and useful form, giving good results, and easily cleaned.
71. Fixed “loco-type,â€with underneath fire-box; sometimes used to economise space, is self-contained, and usually stands on cast-iron feet.
72. Multitubular-horizontal;self contained; on cast-iron feet.
73. Egg-end boiler;not much used except where the coal burnt per h.p. per hour is not an important consideration.
74. “Cornishâ€;one flue, with enlarged fire-box tube. This type is often made with a parallel flue with cross tubes fixed at intervals throughout its length.
75. “Lancashireâ€;two flues; sometimes has enlarged fire-box tubes, asNo. 74.
76. Oval flue boiler,with “Galloway†tubes. The Lancashire type is frequently combined with this form by arranging the two circular flues to open into one oval one.
77&78. “Elephant†boilers;employed in connection with coke ovens and other sources of waste heat.
79. Ordinary box form,with internal fire-box and return flue.
80. Same type,but with two fire-boxes and multitubular return tubes.
81. Underneath fire-boxesand multitubular return tubes above the fire-boxes, sometimes duplicated, asNo. 82.
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83. Has two central fire-boxesand side return-tubes.
The foregoing box patterns are rapidly going out of use, as unsuitable for the higher pressures prevailing with compound engines.
84. Cylindrical boiler,with three fire tubes and three sets of return tubes. This form is much used, the surfaces requiring stays being very limited. It is made with double fire-boxes as shown, or with single fire-box, asNo. 81.
85. Cylindrical single flueand return-tube.
86. Cylindrical single flueand multitubular.
87. Cylindrical double flueand multitubular, longitudinal section similar toNo. 86.
88. Cylindrical saddle boiler,multitubular, used for shallow vessels, launches; &c.
89. Kitchen “ell†boiler.
90. Kitchen or back boiler,for ordinary grates.
91. “Saddle†boiler.The varieties of this type are legion. Every conceivable cross-bridge, water-way, tube, and flue has been added to it by various makers. See Messrs. Graham and Fleming, and other makers’ Lists.
92. Annular cylindricalgreenhouse boiler.
93. Annular conoidalgreenhouse boiler.
94. Vertical cylindrical,closed top greenhouse boiler.
The last four are types of the greenhouse boilers most in use. They are usually of wrought iron, and all seams welded.
95. Back boilerfor ordinary register grate.
96. “Boot†boiler.
97. Scullery, or wash-house boiler.
98. Scullery, or wash-house boiler, heated by steam.In public laundries these are usually rectangular in plan.
99. Coil boiler,used for small greenhouses, &c.
100. Sectional, or “Tubulous†boiler.Root’s, and others, are on this principle. They are constructed of simple pipes andTorLpieces, usually bolted together.
Some of the mechanical blowers are too well known to need illustration here; such are the ordinary Beam Blowing Engine, as in use for blast furnaces, Vertical Blowing Engine, and Horizontal Blowing Engine. In all these a cylinder and piston form the blowing device. Nearly every form of rotary engine (seeSection 75) may, by reversal, be converted into a blowing machine. See Root’s patent,No. 1307; Baker’s,1325, and others in common use. Fans, centrifugal, (seeNo. 1337) are still the commonest blowing machines, and are especially suited for light pressures and large volumes of air; but for pressures of from1â„2lb. per square inch and upwards, the rotary or cylinder types are best. The following are devices not so well known, but sometimesuseful:—
101. The “Trompe,†or water-jet blower.Water under pressure is discharged through a rose into a funnel-shaped inlet, carrying with it a quantity of air (seeSection 45); the water runs off at an overflow, and the air is led away by a pipe.
102. Steam-jet blower.(SeeSection 45.)
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103. Organ bellows.The lower “feeders†pump alternately into the double-tier upper “reservoir,†which has the upper set of ribs inverted, as shown, to equalise the pressure throughout its rise. The reservoir is loaded with weights to the required pressure.
104. Smiths’ bellows,either circular or hinged at one side.
The valves used for bellows are plain flap valves faced with leather similar toNo. 1619.
105. Bell, or gasometer blower,for light pressures and large volumes.
106. Regulator, or reservoir,for blowing engines to steady the blast. The weighted piston serves the same purpose as an air vessel to the ordinary pump.
107. Disc blower,with elastic diaphragm piston.
108. One-crank three-throw blower,for organs, &c., to give a continuous blast. The three feeders deliver into the central triangular box.
The skeleton framing of a machine for any purpose should be rigid, as light as is consistent with strength and stability (in some cases weight is necessary to minimise vibration), and the ribs, or members of the frame, should be so disposed as to afford the requisite support for all bearings, centres, &c., without redundance; and lastly, symmetry, and a certain degree of elegance and proportion, are desirable. The illustrations are necessarily typical only, and suggestive.
109. Girder section bedplatefor horizontal distributed bearing, as in a horizontal engine. It may be used double, and the two parts connected by cross pieces and bolts, asNo. 112.
110. Open box bedplate.
111. Closed box bedplate.
112. Double box bedplatewith cross tie pieces.
Square or rectangular bedplates are usually of similar sections, stiffened with ribs underneath, and generally cast in one piece.
113. Side frame and distance rod construction,suitable for light machines.
114. Side frames and cross barson a base plate. This forms a more rigid construction thanNo. 113.
115. Table and legs.
116. Rectangular openwork box framing.Useful for machines with several cross shafts.
117. Hollow standardfor hammers, vertical engines, and any machine raised above the floor.
118. Soleplate and standardfor pedestal bracket, &c. Admits of being detached without disturbing the foundation.
119. Wall boxfor shaft bearings, &c.
120. Arched crosshead for double bearing,bevil gear, &c.
121. Wrought-iron sideplate and distance rod construction.
122. Wall bracket,with wall flange, or tongue, to take the vertical strain.
123. Wrought-iron rectangular bedplate.