Figs. 1131, 1132. Different kinds of gears for transmitting rotary motion from one shaft to another arranged obliquely thereto.

Fig. 1133. A kind of gearing used to transmit great force and give a continuous bearing to the teeth. Each wheel is composed of 2, 3, or more distinct spur-gears. The teeth, instead of being in line, are arranged in steps to give a continuous bearing. This system is sometimes used for driving screw-propellers, and sometimes, with a rack of similar character, to drive the beds of large iron-planing machines.

Fig. 1134. Frictional grooved gearing - a comparatively recent invention. The diagram to the right is an enlarged section, which can be more easily understood.

Fig. 1135. Alternate circular motion of the horizontal shaft produces a continuous rotary motion of the vertical shaft, by means of the ratchet-wheels secured to the bevel-gears, the ratchet-teeth of the two wheels being set opposite ways, and the pawls acting in opposite directions. The bevel-gears and ratchet-wheels are loose on the shaft, and the pawls attached to arms firmly secured on the shaft.

Fig. 1136. The vertical shaft is made to drive the horizontal one in either direction, as may be desired, by means of the double-clutch and bevel-gears. The gears on the horizontal shaft are loose, and are driven in opposite directions by the third gear; the double-clutch slides upon a key or feather fixed on the horizontal shaft, which is made to rotate either to the right or left, according to the side on which it is engaged.

Mechanical Movements Part 25 993Mechanical Movements Part 25 994Mechanical Movements Part 25 995Mechanical Movements Part 25 996Mechanical Movements Part 25 997Mechanical Movements Part 25 998Mechanical Movements Part 25 999Mechanical Movements Part 25 1000Mechanical Movements Part 25 1001Mechanical Movements Part 25 1002Mechanical Movements Part 25 1003Mechanical Movements Part 25 1004Fig. 1137. Mangle or star wheel, for producing an alternating rotary motion.

Fig. 1137. Mangle or star-wheel, for producing an alternating rotary motion.

Fig. 1138. Different velocity given to 2 gears, A and C, on the same shaft, by the pinion D.

Fig. 1139. The small pulley at the top being the driver, the large, internally-toothed gear and the concentric gear within will bo driven in opposite directions by the bands, and at the same time will impart motion to the intermediate pinion at the bottom, both around its own centre and also around the common centre of the two concentric gears.

Fig. 1140. Jumping or intermittent rotary motion, used for meters and revolution-counters. The drop and attached pawl, carried by a spring at the left, are lifted by pins in the disc at the right. Pins escape first from pawl, which drops into next space of the star-wheel. When pin escapes from drop, spring throws down suddenly the drop, the pin on which strikes the pawl, which, by its action on star-wheel, rapidly gives it a portion of a revolution. This is repeated as each pin passes.

Fig. 1141. Another arrangement of jumping motion. Motion is communicated to worm-gear B by worm or endless screw at the bottom, which is fixed upon the driving shaft. Upon the shaft carrying the worm-gear works another hollow shaft, on which is fixed cam A. A short piece of this hollow shaft is half cut away. A pin fixed in worm-gear shaft turns hollow shaft and cam, the spring which presses on cam holding hollow shaft back against the pin until it arrives a little farther than shown in the figure, when, the direction of the pressure being changed by the peculiar shape of cam, the latter falls down suddenly, independently of worm-wheel, and remains at rest till the pin overtakes it, when the same action is repeated.

Fig. 1142. The left-hand disc or wheel C is the driving wheel, upon which is fixed the tappet A. The other disc or wheel D has a series of equidistant studs projecting from its face. Every rotation of the tappet acting upon one of the studs in the wheel D causes the latter wheel to move the distance of one stud. In order that this may not be exceeded, a lever-like stop is arranged on a fixed centre. This stop operates in a notch cut in wheel C, and at the same instant tappet A strikes a stud, said notch faces the lever. As wheel D rotates the end between studs is thrust out, and the other extremity enters the notch; but immediately on the tappet leaving stud, the lever is again forced up in front of next stud, and is there held by periphery of C pressing on its other end.

Fig. 1143. A modification of Fig. 1141; a weight D, attached to an arm secured in the shaft of the worm-gear, being used instead of spring and cam.

Fig. 1144. Another modification of Fig. 1141; a weight or tumbler E, secured on the hollow shaft, being used instead of spring and cam, and operating in combination with pin C, in the shaft of worm-gear.

Fig. 1145. The single tooth A of the driving wheel B acts in the notches of the wheel C, and turns the latter the distance of one notch in every revolution of 0. No stop is necessary in this movement, as the driving wheel B serves as a lock by fitting into the hollows cut in the circumference of the wheel C between its notches.

Fig. 1146. B, a small wheel with one tooth, is the driver, and the circumference entering between the teeth of the wheel A, serves as a lock or stop while the tooth of the small wheel is out of operation.

Fig. 1147. The driving wheel C has a rim, shown in dotted outline, the exterior of which serves as a bearing and stop for the studs on the other wheel A, when the tappet B is out of contact with the studs. An opening in this rim serves to allow one stud to pass in and another to pass out. The tappet is opposite the middle of this opening.

Fig. 1148. The inner circumference (shown by dotted lines) of the rim of the driving wheel B serves as a lock against which two of the studs in the wheel C rest until the tappet A, striking one of the studs, the next one below passes out from the guard-rim through the lower notch, and another stud enters the rim through the upper notch.

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Fig. 1149. To the driving wheel D is secured a bent spring B; another spring C is attached to a fixed support. As the wheel D revolves, the spring B passes under the strong spring C, which presses it into a tooth of the ratchet-wheel A, which is thus made to rotate. The catch-spring B, being released on its escape from the strong spring C, allows the wheel A to remain at rest till D has made another revolution. The spring C serves as a stop.