17. Disc and ring with 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 adjustment for a lever or similar detail.
19. Wedge bearing for locomotive horn plate guides, slide bars, and similar parts subject to wear.
20. Right and left-hand screw and wedge adjustment for roller bearings, &c.
21. Adjustment for wear used on engine crossheads to take up the wear of the working faces.
Adjustable Crane Balance Weights, Section 18.
Adjustable V-guides, Nos. 700 and 704.
Section 3.—BELT GEARING.
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,” as No. 22.
24. Single-flanged pulley for horizontal driving.
25. Open belt gear; runs best as shown, with the slack half of the belt at top.
26. Crossed belt to reverse motion on the driven shaft. Also to obtain more grip for the belt than with open belts.
27. Mode of driving when the shafts are at right angles to one another.
28. Mode of driving with shafts at an obtuse angle, sometimes used instead of bevel wheels.
29. Arrangement adopted when the pulleys cannot be got in line with 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, see Section 74. Gut bands (round) are worked over V-grooved pulleys; see Rope Gearing, Section 66. Belts may be kept tight by tightening pulleys, see No. 1207. For round belts, see Rope Gearing, Section 66. V-belts are occasionally used, formed of thicknesses of leather riveted together, cut to a V-section, and worked over V-grooved pulleys.
Section 4.—BALL-AND-SOCKET JOINTS.
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.
Larger plate.
32. Same as No. 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 also Nos. 1359 and 732.
Gas pendants are suspended with a joint similar to No. 31, but the ball, having only a restricted angular motion, is cut down to a segment only.
Section 5.—BRAKES AND RETARDING APPLIANCES.
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. See Section 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 brake on 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.
Larger plate.
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 to No. 57. See remarks to No. 41.
59. Wedge and split ring, used for internal brake ring or clutch, in a similar way to No. 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