spindle(redirected from nuclear spindle)
Also found in: Dictionary, Thesaurus, Medical.
Related to nuclear spindle: mitotic spindle
the drawing out, twisting, and winding of fibers into a continuous thread or yarn. From antiquity until the Industrial Revolution, spinning was a household industry. The roughly carded fiber was at first held in one hand and drawn out and twisted by the other hand.
..... Click the link for more information. .
the principal operating member of slubbing, spinning, and twisting machines in textile production. The spindle serves to twist the product of the spinning and to wind it (slubbing, yarn, cord, and so on) onto a reel, spool holder, or bobbin.
The hand spindle appeared in countries of the ancient Orient. Machines with spindles came into use in the second half of the 18th century. A distinction is made between spindles for natural fibers (cotton, wool, or linen) and chemical fibers. A spindle is a long, relatively thin, and flexible steel shaft of complex geometric form. It has two bearings, which as a rule are located on its lower part—roller and ball bearings and sliding step bearings. The upper part of the spindle is equipped with a cap whose configuration is determined by the form of packaging of the product.
The majority of spindles are rotated by a flexible transmission (a belt or strap); some are driven by helical wheels. The spindle for spinning chemical fibers rotates by means of an individual, high-frequency electric motor whose rotor is seated on the spindle. Braking of the spindle, which is necessary to remove a worked bobbin or to fix a break in the yarn, is accomplished by special brakes (mechanical drive) or by countercurrent (electrical drive). Spindles are usually attached to the beam of a machine by means of special nuts, gaskets, and springs; some spindles can be turned around by means of special arms. All modern spindles have a damper device, which decreases shaft vibration during rotation. The frequency of rotation of spindles varies in processing various fibers from 2,500 to 16,000 or more rpm.
A serial spindle for spinning natural fibers is shown in Figure 1. A paper holder or wooden spool is fitted tightly on the upper part of the shaft; the yarn winds onto it in the form of a cop. On the way to the spindle, the thread passes over a runner that slides along an immovable ring around the spindle. When the spindle rotates, the yarn is pulled and causes the runner to move along the ring, thus twisting the yarn and winding it onto the holder.
Soviet specialists have developed an original spindle for spinning-twisting machines, which has made it possible to combine spinning, slubbing, roving, twisting, and winding of two threads (Figure 2). The hollow shaft of the spinning-twisting spindle rotates on two ball bearings enclosed in rubber rings. The rings are enclosed in a housing consisting of two halves. The holder for the yarn taken from the spinning machine is seated on the upper end of the spindle; the lower end of the yarn goes through an opening in the shaft. The strand of yarn enters the interior canal of the spindle from the drawing instrument. When the spindle rotates, the yarn from the holder runs along the flange of the shaft canal and causes the strand to rotate around its axis, converting it into yarn. Throwing occurs at the top of the spindle; on the way from the top of the spindle to the winding reels two threads of yarn are twisted in reverse direction, and then the thread is wound on a bobbin.
An electric spindle for the formation—sometimes incorrectly called spinning—of viscose fibers is shown in Figure 3. The rotor of a three-phase asynchronous bipolar electric motor is rigidly mounted on a bushing. In order to transmit rotation frequencies on the order of 6,000-9,000 rpm to the spindle, the electric motor is fed a higher-frequency current (100-200 hertz) obtained from special converters. The viscose fiber enters the well through a thread guide that moves back and forth and, under the influence of centrifugal force, it is laid out in a spiral line on the wall of the well. Twisted yarns are obtained in the same way on various types of centrifugal spindles for natural fibers. In spinning chemical fibers, there is a tendency to create electrical spindles using ball bearings with packed lubricating grease, which is changed once every one or two years. Spindles with a rigid drive rotated by a screw coupling have come into use to a certain extent for spinning wool. Their principal advantage is the stability of the rotation frequency of the shaft (constancy of the twist of the yarn), which is necessary in order to obtain high-quality yarn. Spinning machines with spindles that have irregularly shaped caps on the ends of their shafts are also used in order to decrease the number of breaks in the yarn. The caps diminish the ball of thread that forms during twisting, which leads to lowering the tension of the yarn and to breakage.
Double-twist spindles are used in the production of heavy threads for carpets, belting, cord, and rope. Such spindles are twice as productive as ordinary spindles, but their construction is complicated.
In the USSR and abroad, work is under way to substitute light oil for lubricating grease and roller bearings for sliding bearings, to increase the rotation frequency of the spindle and the quantity of bundles produced, to use sliding bearings made of special materials that require no lubricants and to use air bearings, and to increase the reliability and durability of spindles. A theory of spindle vibration has been developed by Soviet scientists.
REFERENCESMalyshev, A. P. Vereteno. Moscow, 1950.
Osnovy proektirovaniia tekstil’nykh mashin. Moscow, 1961.
Osnovy proektirovaniia priadil’nykh mashin. Moscow-Leningrad, 1946.
Koritysskii, Ia. I. Issledovaniia dinamiki i konstruktsii vysokoproizvoditel’nykh vereten tekstil’nykh mashin. Moscow, 1963.
I. V. KORNEV
the operating shaft of a metal-cutting machine tool. Either the tool (milling cutter, drill, grinding wheel, or the like) or the workpiece being machined may be attached to the spindle. Great demands are placed on a spindle with respect to rotational precision, which significantly affects the accuracy of machining. Thus, spindles are mounted on precision rolling-contact bearings or plain bearings; the spindles of internal grinding machines that exhibit particularly high rotation speeds (up to 100,000 rpm) are mounted on gas-lubricated plain bearings. The spindle may use a gear or belt drive, or it may be driven directly by a built-in electric motor or compressed-air turbine.