Types of Belts and Pulleys Research Paper Example | Topics and Well Written Essays - 2500 words

Types of Belts and Pulleys - Research Paper Example These belts are categorized into industrial (narrow, conventional, light-duty and double V cross section), automotive and agricultural. V belts have reinforcing cords in the belt that provide load-carrying capacity. This reinforcement is made of nylon, steel, rayon or glass fibers embedded in a cushion section (soft rubber material). The cushion section is externally covered with tough rubber and the interior is covered with a material that is resistant to abrasion. As the belt bends around the pulley, the length of its pitch line remains the same. The pitch diameter if the pulley is determined using the pitch line (Jadon & Verma, 2010). Flat belts:These types of belts are normally used in applications where high speeds are required or long center distances are involved. Flat belts are more efficient at high speeds compared to low speeds since they tend to slip under load. They are also used where drives which have nonparallel shafts are necessary as they allow twisting to contain th e relationship of the shafts. Positive drive belts:These belts have a notched underside that establishes contact with a pulley with similar design on the circumference. The belts have similar benefits to chain and gear drives because of their positive contact with the pulley. Positive drive belts are appropriate in operations where high efficiency, constant velocity of timing is required. They can also be used to reduce the size of the pulley and provide the same operating performance as large sized V-belt pulleys (Jadon & Verma, 2010).... Pulleys Pulleys are components that are used for power transmission in machines by mounting them on shafts over which belts run. These components are generally made of iron, steel plates or by welded construction. Pulleys may be of a split type or a single piece depending on the application. The types of pulleys can be categorized based on the belts used with the pulley into: a. Flat belt pulleys: These pulleys are of varying shapes and sizes, designed to fit the functional requirements. The main types of pulleys used with flat belts include: Armed Pulley The boss, spokes/arms and rim are the main parts of a pulley. The arms of the pulley are either curved or straight while the cross section is the shape of an ellipse. The rims of these pulleys have a slight convexity to prevent the belt from axial slipping during operation. Pulley with a Web The boss and rim of a pulley are connected with a web in the form of a disk when the diameter of the pulley is very small. Holes are made in th e web to make the pulley lighter. Cone Pulleys These types of pulley are mounted on the driver and driven shafts facing opposite sides to offer varying speed ratios between the two and maintain the speed of the driver shaft at a constant. The steps in the two pulleys have a diameter designed such that one belt can operate on the surface of any pair of steps. This type of pulley is used in drilling machines and lathes. Fast and Loose Pulleys In applications that involve a number of machines operated from one source of power, each machine has a fast and loose pulley configuration. Using this arrangement, any machine can be stopped or started independently while the shaft runs. Using a keyed joint, the fast pulley is mounted on the shaft

What my reason is for wanting to become a nurse Essay

What my reason is for wanting to become a nurse - Essay Example I was a child who attracted stray dogs, a small turtle who wouldn’t eat for a week, a butterfly with a bent wing, and a runaway lizard I tried to comfort while it was re-growing a lost tail. While other children licked cotton candy, I focused on whether zoo animals had enough food and water, so they would be healthy and happy during their confinement. I gave backrubs to anyone in need. I visited a family friend in the hospital and eagerly breathed in the smell and sounds of this place where they fix people. When my mother became pregnant, I participated in preparing the nursery and shopping for our upcoming addition. I made lists of things I would teach the new baby, people we should tell about the baby, and my suggestions for names. Everyone was happy. When he arrived, my baby brother looked different from other babies. I learned he had Down Syndrome. He would be mentally retarded and would not be able to do all the things on my list. He would require help to have a good life. I appointed myself to take charge. I collected information, and I thought maybe I could fix what was wrong, As my baby brother grew into toddlerhood, he seemed tired. He had a congenital heart defect. My family was sad and afraid. We adored him and wanted everything good for him, and now there was a new challenge. I prayed. I gave up things I liked, hoping it would be a trade for things my brother needed. But at 14 months of age, we lost him. I tried to understand how my excellent mind, my love, and enthusiastic efforts were not enough. Eventually I came to understand that helping a person may not always mean fixing them. With my parents’ help, I came to see that my support, love and caring had been just what he needed during his precious, short life. I feel that I was given a gift to make a difference in the lives of people who are ill. I cannot heal every life I come into contact with, but I want to