Theory of Machines

Fig. 4.2. Spur Gear and Pinion pair Terms used in Gear Addendum: The radial distance between the Pitch Circle and the top of the teeth. Dedendum: The radial distance between the bottom of the tooth to pitch circle. Base Circle: The circle from which is generated the involute curve upon which the tooth profile is based. Center Distance: The distance between centers of two…

Helical gears may be used to mesh two shaftsthat are not parallel, although they are still primarily use in parallel shaft applications. A special application in which helical gears are used is a crossed gear mesh, in which the two shafts are perpendicular to each other. Crossed-helical gears Worm and worm gear: Worm gears are used…

1.      Spur gears: Spur gears are the most common type of gears. They have straight teeth,and are mounted on parallel shafts. Sometimes, many spur gears are used at once to create very large gear reductions. Each time a gear tooth engages a tooth on the other gear, the teeth collide, and this impact makes a noise. It…

According to the Position of Axis of Shaft (a) Parallel (b) Intersecting  (c) Non-intersecting and non-parallel According to the peripheral velocity of the gears (a) Low velocity, less than 3 m/s  (b) Medium velocity, between 3 and 15 m/s (c) High velocity. more than 15 m According to the type of gearing (a)External gearing (b)…

The following are the advantages and disadvantages of the gear drive as compared to belt, rope and chain drives: Advantages: 1.                 It transmits exact velocity ratio. 2.                 It may be used to transmit large power. 3.                 It has high efficiency. 4.                 It has reliable service. 5.                 It has compact layout. Disadvantages: 1.     The manufacture of gears requires special tools and equipment….

Introduction The slip and creep in the belt or rope drives is a common phenomenon, in the transmission of motion or power between two shafts. The effect of slip is to reduce the velocity ratio of the drive. In precision machine, in which a definite velocity ratio is importance (as in watch mechanism, special purpose…

Cam follower systems are designed to achieve a desired oscillatory motion. Appropriate displacement patterns are to be selected for this purpose, before designing the cam surface. The cam is assumed to rotate at a constant speed and the follower raises, dwells, returns to its original position and dwells again through specified angles of rotation of…

Cams can be classified based on their physical shape. a) Disk or plate cam (Fig. 3.4 a and b): The disk (or plate) cam has an irregular contourto impart a specific motion to the follower. The follower moves in a plane perpendicular to the axis of rotation of the camshaft and is held in contact…