TOOTHED BELT

There are two motors, i.e., motors I and II, to drive the rotor. When motor I drives frame I, the stationary pulley 1 introduces counterrotation of pulley II through a toothed belt therefore, countershaft I rotates at — coj with respect to rotating frame I. This motion is further conveyed to the centerpiece by 1 1 gearing between gears 1 and 2. Thus, the centerpiece rotates at 2coi or at coj with respect to the rotating frame I. The motion of frame I also depends upon the motion of motor II. 

Fig. 3 Design of helix CCC (toroidal coil CCC) apparatus. A, Schematic drawing of centrifuge head of original helix CCC apparatus B, cross-sectional view of advanced design of helix CCC equipped with seal-free flow-through device. 1, Motor 2, toothed pulleys 3, toothed belt 4, stationary miter gear 5, horizontal idler miter gear 6, inverted upper miter gear mounted at bottom of column holder shaft (8) 7, gear box 9, column holder 10, coiled separation column 11, hollow tube support 12, flow tubes and 13, clamps.

If motor II is at rest, pulley 5 becomes stationary same with pulley 1 so that countershaft II counterrotates at uji as does countershaft I. This motion is similarly conveyed to the rotary arms of frame II by 1 1 gearing between gears 3 and 4, resulting in rotation of frame II at 2toi or the same angular velocity as that of the centerpiece. Consequently, coupling of pulleys 6 to 7 and 8 to 9 with toothed belts produces no additional motion to the rotary shaft, which simply revolves with frame II at 2o i around the central axis of the apparatus. 

There are three basic tooth configurations associated with synchronous belts. The standard trapezoidal shape was introduced in the 1940s. In the 1970s the high torque drive (HTD) belt was introduced with a round-shaped tooth. In more recent years a number of modified curvilinear tooth belts have been introduced with a tooth shape similar to gear teeth (Fig. 5.80). It is very important that each belt type be run in compatible pulleys or sprockets. 

The Mtinstedt tensile rheometer (MTR) is an end-separation device in which the sample is stretched vertically in a cylindrical oil bath [ 199]. This is an improved version of the universal extensional rheometer described by Mtinstedt etal. [177]. The basic idea is illustrated in Fig. 10.23. The specimen is fastened by an adhesive to small metal plates, one of which is attached to a force transducer at the bottom of the bath, and the other is coupled to a pull rod that is vertically displaced by a toothed belt driven by a motor. This instrument has been used for a number of important studies [ 158,191 ]. The MTR can reach strain rates of 5 s and can be used for creep measurements. The temperature is limited to about 220 °C because of the physical properties of the silicone oil used to fill the bath. 

Drives is the term given to power-transmission equipment. The simplest form of power transmission is a belt drive. A belt drive can have a flat, V-belt, ribbed belt, or toothed belt design. These drives are common in applications such as conveyors. Conveyor manufacturers should be consulted for their catalogues on power-transmission capability. 

Mechanical transmission (power-grip toothed-belt drive) (see Fig. P-72)... 

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