CHAIN GEAR. 41. SPROCKET WHEEL.-The wheel is provided with teeth adapted to fit in between the links of a chain. The chain may be of the ordinary oval welded link type or of the flat riveted type used on bicycles. 42. LINK-BELT WHEEL.-The chain is made up of square links which are engaged by ratchet-shaped teeth on the chain wheel. 43. POCKET WHEEL.-The wheel is formed with pockets into which the links of the chain are adapted to fit. 44. SIDE-TOOTHED WHEEL.-The wheel is formed with two sets of teeth between which the chain travels. The teeth bear against the ends of the outer links of the chain. 45. SIDE AND CENTER TOOTHED CHAIN WHEEL. This wheel is similar to that shown in Fig. 44, but has in addition a row of teeth along the center which bear against the center link of the chain. 46. TOOTHED-LINK CHAIN AND WHEEL.The links are formed with projecting teeth which fit into notches on the rim of the chain wheel. 47. SILENT" CHAIN AND WHEEL. This is a special type of chain in which each link is formed with a tooth at each end. The teeth of adjacent links coact to completely fill the spaces between the teeth of the chain wheel. The construction is such as to produce a noiseless operation of the chain gear even at high speeds. 48. DETACHABLE TOOTHED-LINK BELT AND WHEEL. Each link is formed with a tooth, which meshes with the teeth of the chain wheel. The construction of each link is such that it may be readily slipped into or out of engagement with the next link of the chain. ROPE GEAR. 49. V-PULLEY.-The ordinary type of pulley for round ropes or cables. Owing to the V-shaped construction of the pulley groove, the rope wedges tightly into engagement with the pulley. 50. PULLEY WITH FLEXIBLE FILLING.-In order to secure frictional engagement of the cable with this pulley, the pulley groove is provided with rubber, leather, wooden, or other filling. 51. PULLEY WITH RIBBED GROOVE.-In this construction of pulley the required grip is produced by forming ribs in the bottom of a pulley groove. 52. PULLEY WITH GRIPPING LUGS.-The flanges of this pulley are formed with lugs which kink the rope or cable as shown, thus producing the required grip. 53. ROPE SPROCKET-WHEEL.-An old form of rope gear used in hoists and the like. 54 and 55. GRIPPING PULLEYS.-Gripping arms are provided which grip the cable at the point where the cable presses into the pulley. In 54 the gripping arms are wedged inward by the side walls of the pulley groove when pressed downward by the cable. These arms are normally h ld up by coil springs. In 55 the cable is gripped by the toggle movement of hinged clips placed at intervals along the periphery of the pulley. 56. CABLE SPROCKET-WHEEL.-The cable is provided with clamps which enter sockets formed in the cable wheel. This is a form of cable gear commonly used at present in elevating and conveying machinery. CLUTCHES. 57. COMMON JAW CLUTCH.-One member of the clutch is mounted to slide on a feathered shaft, and the other member which is connected with the machinery is normally stationary on this shaft. When the slidable member is moved forward the teeth on its forward edge intermesh with the teeth of the other member, setting the machinery in motion. The slidable member is moved forward by means of a forked lever which is hinged to a split collar mounted loosely between flanges on the clutch member. 58. CLAW CLUTCH.-The slidable member of the clutch consists of a body portion with two claw arms which, when moved forward, are adapted to engage opposite sides of a bar on the other member of the clutch. 59. LEVER CLUTCH.-The slidable member is provided with a lever loosely hinged to its forward end. The other member of the clutch consists of a disk formed with ratchet teeth on its face. These are engaged by the hinged arm when the shaft rotates in one direction, but the arm moves freely over them when rotated in the opposite direction. 60. KNEE AND ROSE CLUTCH.-A crank arm is attached to the slidable member of the clutch, and engages a pin on an arm loosely hinged to the opposite member of the clutch. 61. RATCHET CLUTCH.-The clutch members are formed with ratchet teeth, so that when the motion of the driving shaft is reversed, the members will be disengaged. 62. PIN CLUTCH.-The slidable member is provided with radial arms formed with pins at their outer ends which are adapted to enter sockets formed along the periphery of a disk on the opposite member of the clutch. two 63. FRICTION DISK CLUTCH.-The clutch members are each formed with disks preferably faced with rubber or leather, so that when pressed together their frictional engagement will cause a transmission of motion from the rotating disk to the other. 64. FRICTION GROOVE CLUTCH.-One of the clutch members is formed with a groove in its face to receive the lip of the other member which is cup-shaped. Both the lip and the side walls of the groove are slightly tapered to insure a close fit, even after the parts have been partly worn away by friction. 65. STUD CLUTCH. -Engagement between the two members of the clutch is effected by means of a stud on each disk adapted to enter a notch formed in the periphery of the opposing disk. 66. FRICTION BAND CLUTCH.-One member of the clutch consists of a pulley provided with a steel band which encircles and fits tightly on its periphery. The other member of the clutch consists of a lever provided with pins at its outer ends, which are adapted to engage the steel band." Since this band is not fastened to the pulley, any shock due to suddenly throwing the clutch members into engagement will be taken up by the steel band slipping on the face of the pulley. 67. FRICTION CONE CLUTCH.-The clutch is made up of two cones, one adapted to fit into the other. The frictional engagement causes one to drive the other. 68. SELF-RELEASING CLUTCH.-The clutch disks are provided with inclined teeth, so that in case the resistance to the driven shaft in creases beyond a certain degree, the clutch members will automatically move apart. 69. CAM CLUTCH.-One of the members is cup shaped, and within this the other member operates. The latter comprises a number of cam-shaped arms hinged to a body portion, and so arranged that when moved in one direction they will bind against the inner wall of the drum, but when moved in the opposite direction they will be automatically disengaged therefrom. 70. V-GROOVED CLUTCH.-The clutch disks are formed with annular V-grooves adapted to fit into each other, and thus increase the friction surface of the clutch members. 71. EXPANSION CLUTCH.- The slidable member is provided with a number of movable ring segments connected by radial arms to the main body of the clutch and adapted to bear against the inner surface of the drum or cup which constitutes the other member of the clutch. When the slidable member is moved forward, by reason of the toggle action of the radial arms, the segments are brought into frictional engagement with the other member of the clutch. 72. COIL-GRIP CLUTCH. The movable member of the clutch is formed with a number of coils of steel in which there is a central conical opening. This is moved over the cone which constitutes the opposite member of the clutch, producing the required frictional engagement of the two members. ANGLE SHAFT COUPLINGS AND UNIVERSAL JOINTS. 73. CRANK AND HINGED-PIN COUPLING.— A coupling for shafts which lie at an angle to each other. One shaft carries a hinged pin which fits into an opening in the outer end of a crank arm carried by the other shaft. 74. DOUBLE-SLEEVE ANGLE COUPLING.Each shaft carries a crank arm provided with a pin at its outer end, which lies parallel with its respective shaft. The two pins enter a coupling device consisting of two sleeves integrally formed, but lying at an angle with each other which corresponds to the angle formed by the shafts. Through this doublesleeve coupling, motion is transmitted from one shaft to the other, the pins sliding back and forth in the sleeve openings. 75. CROSS-BAR ANGLE COUPLING.-This is used for coupling two parallel but offset shafts. Each shaft carries a yoke piece provided with sleeves at its outer ends. The coupling member is a cross-shaped piece, its arms fitting into the sleeves of the yoke pieces, and permitting the necessary lateral play as the shaft rotates. This form coupling is also applicable to shafts which lie at an angle with each other. of The 76. PIN AND SLOT COUPLING.-A crank pin carried by one shaft engages a slot in a crank arm carried by the other shaft. motion transmitted is variable, due to the fact that the leverage varies as the pin moves up and down in the slot. 77. RING-GIMBAL UNIVERSAL JOINT-The ends of the shafts are provided with yoke members whose arms are pivoted to a ringgimbal, the pivot pins of the two yoke pieces lying at right angles to each other. coupling will communicate motion at any angle under 45 degs. For angles of over 45 degs. a double-link universal joint is used, This 78. DOUBLE-LINK UNIVERSAL JOINT.-A link forked at each end is hinged to two rings, which are mounted in the yoke pieces on the ends of the shafts. In place of rings cross pieces such as shown in the illustration are often used. 79. HOOKE'S ANGULAR COUPLING.-The shafts are connected by two double links which are arranged in the form of a parallelogram. Intermediate of the shafts the links are connected with ball-and-socket joints. 80. BALL-AND-SOCKET UNIVERSAL JOINT.— Socket pieces are secured to the ends of the shafts, and these are provided with metal bands which encircle the ball that constitutes the coupling member. The bands enter grooves in the ball which lie at right angles to each other. 81. ALMOND " ANGULAR COUPLING.-A side view of the coupling is shown at 1 and a plan view at 2. Between the shafts to be coupled is a fixed stud on which a bell crank is mounted to turn. The bell crank is permitted to slide axially on the stud. The bell crank is connected at the ends by balland-socket joints with links attached to the ends of the shafts. Now, as the power shaft rotates, rotary motion will be communicated to the other shaft through the bell crank, which will rock and also slide axially on the stud. 82. FLEXIBLE SHAFT.-Two shafts are connected by a flexible shaft consisting of a coil spring, or a metal tube in which a helical sawslot has been cut. This flexible shaft will permit transmission of motion through a wide angular range. 83. LINKED FLEXIBLE SHAFT.-The flexible shaft is made up of a series of links coupled together with universal joints. A coil spring fits loosely over the links and prevents them from kinking. This spring in turn is covered with a flexible tube. The shaft will transmit motion about almost any curve or angle. It can be used for heavy work. 84. RIGHT-ANGle Coupling. The ends of the shafts are formed with heads in which are drilled a number of sockets. A series of rods, each bent to form a right angle, enter these slots and form the coupling links between the shafts. As the shafts rotate these rods slide in and out of their sockets. RATCHET MOVEMENTS. 85. The teeth of a ratchet wheel are engaged by a pawl hinged to a rocking arm. The ratchet wheel is rotated only on the forward stroke of the arm. 86. A rocking lever carries two pawls, one on each side of its fulcrum. The wheel is rotated both by the downward and the return stroke of the lever; for while one pawl is rotating the wheel, the other swings to position to take a new hold on the ratchet wheel. The rotation of the ratchet wheel is thus kept nearly constant. 87. A ratchet crown-wheel or rag-wheel is engaged by pawls depending from two arms loosely pivoted on the axle of the ratchet-wheel. These two arms are connected by links to a common power arm. Rectilinear reciprocating movement of the latter in the line of the arrow produces an almost constant rotation of the ratchetwheel, |