An Inverted Tooth Chain Engineering Essay

An Inverted Tooth Chain Engineering Essay An inverted-tooth chain operates quietly and smoothly and is also known as a silent chain. Silent chain consists of a series of toothed link plates assembled on joint components in a way that allows free flexing between each pitch. The teeth on the link plates mesh with a sprocket, similar to the way a rack meshes with a gear. The great majority of silent chain is used in drives. Silent chains are made up of stacked rows of load carrying link plates. Increasing the number of rows of links increases the chain width, tensile strength, and load carrying capacity. Using this feature, manufacturers make silent chains ranging from less than a 1 in. wide to more than 20 in. wide, with power capacities ranging from a fraction of a horsepower to more than 2000 hp. A chain is a reliable machine component, which transmits power by means of tensile forces, and is used primarily for power transmission and conveyance systems. The function and uses of chain are similar to a belt. There are many kinds of chain. It is convenient to sort types of chain by either material of composition or method of construction. There are five types of chains: Cast iron chain Cast steel chain Forged chain Steel chain Plastic chain Demand for the first three chain types is now decreasing; they are only used in some special situations. For example, cast iron chain is part of water-treatment equipment; forged chain is used in overhead conveyors for automobile factories. History: Chains have been used for centuries to drive machines and move materials on conveyors and elevators. In 225 B C, Philo described a chain- driven water lift. Leonard da Vinci sketched the chain designs in the 1500s. Some are similar to modern bar link, leaf, and silent chains. Cog chain was developed in the early 1800s to transmit power or motion between the shafts of treadmills to water elevators, weaving looms and harvesting machinery. This chain was used to mechanize farm implements, but it broke easily and was difficult to repair in the field. Cast detachable chain was introduced in 1873 and overcome many of the problems of cog chain. This chain was made of simple identical cast links that were easily coupled and uncoupled by hand. This basic detachable chain design is one of the early chain concepts that have been unchanged nowadays also. After few years cast detachable chain was introduced, a chain made of all steel parts was introduced for driving bicycles. A patent for roller chain was issued in 1880. By early 1900s, roller chains drove the wheels of safety bicycles, as well as automobiles, trucks, and the propellers of the Wright Brothers airplane that flew at Kitty Hawk. Two major factors combined to make the roller chain industry were automation and standardization. Automation helped manufacturers meet the demand for the large amounts of high quality that were used on machines made by other industries. Standard dimensions and capacities ensured that roller chains would fit and operate as the designer planned. The result was that the industry soon became as the precision roller chain industry. Engineering steel chains were first developed in the 1880s. They were developed for greater strength, speed and shock resistance and for better dimensional control than could be obtained from cast chains. Pitch, strength, wear life, and carrying capacity were increased to meet the heavy duty needs of industry. There are many types of engineering steel chains. Those with steel rollers are the most widely used on both drives and conveyors. The bushed, roller less style are the needs of many conveyor and bucket elevator applications. Sir Isambard Kingdom Brunel supervised the building of the Great Britain, and it was a revolutionary ship design. It was the first sea going iron steamship, the first propeller driven steamship to cross the Atlantic, and the first vessel driven by inverted tooth, or silent chain. The silent chain drive delivered power from the engines to the propeller shaft by way of large wooden- tooth sprockets. From 1895 to 1925, the chain industry improved the design of silent chains. From 1930 onwards, silent chain was used in a variety of industrial applications such as drives in paper and textile mills, flour and feed mills, printing presses, pumps and machine tools. Throughout the 20th century, the industry improved material quality, processing technology, and chain designs to increase the load and speed capacity of silent chain. Silent chain is also used in the drive train of snowmobiles and four wheel drive recreational vehicles. Outside the power transmission market, silent chain can be used as a conveying surface in a variety of material transport applications. Major improvements were made in the production of food and beverage products. The introduction of high speed processing, filling, and packaging equipment drove the need for a chain with a flat carrying surface for material handling. The first flat-top chains were produced by welding steel plates to roller chain, producing a flat surface where products or packages could be carried. These first flat-top chains were made of carbon and corrosion resistant steel and were widely used in the brewing industry to convey glass bottles. Construction and Features: Silent Chains have a very simple construction: only plates and pins. Silent Chains are actually an update of a 19th-century design.  ANSI  B29.2M-1982 regulates the standard pitch, width, and kilowatt ratings of the chains and sprockets. There are eight different pitches from 9.52 mm to 50.8 mm. The link plate receives tension and has a notch for engaging the sprockets. There is no notch on the guide plate. These plates act as guides for the sprockets. Pins may be round or have other shapes, such as D-shape. All the chain components share the tension. Silent Chains have higher capacity than roller chains of the same width. Since the link plates of Silent Chain strike the sprocket at an angle, the impact and the noise are reduced. This is why these chains are called silent. The higher the chain speed, the greater the difference from roller chains. Driving Links: Driving links, also known as plain links, engage with sprocket teeth to drive the chain. They are typically the most common component in the chain. Guide Links: Guide links maintain proper tracking of the chain on sprockets. They are positioned on the outer edges of the chain in side guide and multi guide chain or in the centre, with the centre guide chain. Pins: Pins allow the chain joint to flex and hold the assembled chain together. Chains may have a single pin in each joint or two pins, depending on the chain type. Design considerations: Tensile loads and strength: Silent chain with single pin assembly may be subjected to all of the tensile loads, but silent chain with two pin assembly eliminates chordal action. It is not affectd much by tensile loads from chordal action. Fatigue limit: It is a most important consideration in designing silent chains. The lower speed part of the power ratings for silent chain is based on a minimum fatigue limit. Fatigue strength: Loads exceed the fatigue limit in very high performance drives. The chain must have adequate fatigue strength to endure these loads only if the chain is to be used in high performance drives. Fatigue strength in the finite life range is an important consideration in designing silent chains. Wear: Wear is an important consideration in designing silent chain. The two major types of wears are joint wear and link plate and sprocket wear. Joint wear: As the chain runs over the sprockets, the joints flex. Material is worn off the joint components and chain gets longer. Then chain then rides out farther on the sprocket teeth. This increase noise and reduce efficiency. Link plate and sprocket wear: These wears are also caused by friction on the chains which reduces the efficiency of the silent chains. Advantages of silent chain drives: Silent chain drives require nearly as precise alignment as gear drives to obtain peak performance and service life. †¢ Silent chains are less affected by chordal action and joint friction than other chains; silent chains engage sprockets with reduced vibration, noise, and frictional losses. †¢ Silent chain can operate at loads and speeds that often exceed the capability of belts and other types of chain. †¢ Silent chain drives are quieter and smoother than roller chain drives, and in some cases are quieter than gear drives. †¢ Silent chain drives are more compact than gear drives when the shafts must turn in the same direction. Manufacturers of inverted tooth chain are: Bosch Rexroth AG, Germany:- Bosch Rexroth is an engineering company based in Germany. It is the result of merging between Mannesmann Rexroth AG and the Automation Technology Business Unit of Robert Bosch. It employs over 35,000 people worldwide. The industries Bosch Rexroth serves are Agricultural machinery, automotive manufacturing, Machine tools, Civil engineering and many more. Rexroths inverted tooth chains: The largest delivery program in the world for inverted tooth chains used for driving and transporting are from Rexroth. Rexroths new inverted tooth conveyor chains come with the axle pivots welded to the outer plate by laser. This new technology prevents lateral movement of the joint pivots. These innovative inverted tooth conveyor chains are fully interchangeable with previous design and the sprockets do not require any machining. .Advantages of Bosch Rexroth inverted tooth chain drives over: Gears / Transmissions Belts Roller Chains Reduced bearing loads Non-slip Rolling pivot joint Insensitive to temperature fluctuations Higher Speeds High maximum velocity No need for intermediate sprocket Silent no whistling Low-noise Zero tooth flank backlash Space-saving Smooth running due to involute toothing running Larger permissible tolerances for shaft installation Small sprocket diameters 99% efficiency Vibration damping Insensitive to extreme temperatures or humidity levels Wear-resistant sprockets Low-cost sprockets Reduced bearing loads Vibration damping The advantages over other conveyor systems are: Due to high power density, the space used is optimum Extremely long service life and availability Very low lubrication requirements High temperature tolerance Highly robust and resistant Comparison with different types: Characteristics Tooth chains Roller chains Toothed belts Toothed wheels Noise behaviour Very good Average Bad Good Temperature sensitivity Good Good Bad Good Space required Good Average Bad Very good Wear Good Bad Average Very good Maintenance Partly necessary Necessary Not necessary Not necessary Ramsey Products in USA is another major company. Ramsey manufactures an extensive range of silent chain and sprockets for use in industrial power transmission and conveying applications. For the companies that work with glass, silent conveying chains offer many benefits in applications like handling to precision inspection and measurement from hot-end and cold-end. These chains are made through hardened steel link plates and case hardened steel pins. Characteristics of Ramsey chain: Flatness and uniformity: The flat, uniform surface of the chain provides transport of smaller bottles without any trouble. Surface velocity: The chain wears, the pitch increases uniformly throughout the chain, and velocity remains constant. Uniform velocity reduces breakage. Heat resistance: The temperatures are high with hot-end handling, to withstand these temperatures chains are made from hardened steel. Heat transfer from transported glassware and heating torches does not effect the uniformity of the conveyor surface. Economy: Improved product handling, and requires very less maintenance, chain provides a cost effective means for conveying glassware in high speed production lines. Types of chain: Ramsey manufactures four basic types of conveyor chain. Ultralife Standard Lo-profile Extended pitch Ultralife are best quality conveyor chain. They consists single pin and two pin assembly. The straight edge of the aperture maximizes the link area contacting the pins and reduces joint bearing stresses and wear. Single pin joints provide a durable, smooth acting joint, satisfactory life, and easy to install than two pin joints. These are developed specifically for the glass industry. Two pin joints are originally developed for use in power transmission and have been adapted for use in conveying chains. They have the advantages such as long life, low friction and high efficiency. Advantages of Ramsey silent chain over : Gears / Transmissions Belts Roller Chains Greater elasticity and shock absorption capability No slippage Longer sprocket life Less critical shaft location and alignment Higher Speed and power capacity High speed and power capacity No end thrust Greater efficiency 99% efficiency Detachable and easily replaced Easily installed More uniform wear characteristics Lower bearing loads Lower bearing loads Less velocity variation More economical with large centre distances Larger drive ratios Reduced noise and vibration Reduced noise and vibration Less affected by temperature Less affected by chordal action R. Prinz KG Maschinenfabrik, Austria Wippermann jr. GmbH, Germany ZITEC Industrietechnik GmbH, Germany These are major companies in manufacture of inverted chain and exporting them. There are many small industries in China, India which manufacture these chains. Applications of Inverted tooth chains: Roller table drive applications Cost-efficient group drive Uniform synchronous running No backlash when reversing Quiet even at high speeds Good meshing conditions minimize wear Outer tooth ring applications More cost-efficient than a milled tooth ring Suitable for large transmission ratios Full circle rotary motion or swivel motion along an angle segment possible in reverse or continuously Gripper and robot drive applications Precise synchronized motion High load capacity even at narrow widths Optimum meshing depth on the toothing provides a high a degree of security against skipping Flexible shaft coupling applications High elasticity Uncouples quickly by opening the lock or by radial offset when closed Angles can be shifted to 1 ° and shafts can be shifted radially to 2% of the pitch

Level 3 Diploma in Health and Social Care, Children and Young People Unit 11 Essay

Poverty can have a huge impact on a Young Persons life. A family living on a low –income or benefits might not be able to provide for their children as they would like or as is necessary. Accommodation may be poor and inadequate, with not enough space or functioning essential home items. Money may not be available to pay the energy bills. The children’s dietary needs may be affected by low income. The local community in low-income areas may be impoverished. This may lead to a higher crime rate, vandalism of local amenities, reducing the Young Person access to local parks and playgrounds and affecting them being able to play outside of the house at leisure time. The prospects of a lack of continued higher education after school and fulfilling employment in impoverished areas could affect the Young Persons outlook on life causing fear and insecurities and a lack of motivation. In some research carried out by the Joseph Rowntree Foundation in 2007 into the impact of poverty on young children’s experience of school, the key points found from interviewing 220 children aged Four to Eleven as well as parents and teachers were The level of disadvantage they face determines how most children experience school. Poorer children in the study accepted that they were not going to get the same quality of schooling, or the same outcomes, as better-off children. Children and parents identified the main costs of school as uniform (including shoes), lunches and school trips. Children in disadvantaged schools were very aware of all the costs and of the difficulties parents faced in finding as little as 50 pence or a pound for school events. The experiences of school for children from poorer families were narrower and less rich. For example, children in disadvantaged schools had limited access to music, art and out-of-school activities that children in advantaged schools generally took for granted. Boys as young as nine in disadvantaged schools were disenchanted with school and starting to disengage. They are being particularly failed by the education system due to the interaction of: educational disadvantage faced by children growing up in poverty; the difficulties faced by teachers in disadvantaged schools; and differences in the ways that boys and girls are socialised. Social Issues – Divorce introduces a massive change into the life of a child no matter what the age. Witnessing the loss of love between parents, having parents break their marriage commitment, adjusting to going back and forth between two different households, and the daily absence of one parent while living with the other, all create a challenging new family circumstance in which to live. In the personal history of the boy or girl, parental divorce is a life-changing event. Life that follows is significantly changed from how it was before. For the young child, divorce affects the trust of the parents who can now behave in an extremely undependable way due to their own problems and life changing circumstances. This can produce anxiety, aggression and rebellious behaviours in a child. Cultural – I have chosen to look at one aspect of Culture and that is Religion and it’s positive effects on young people. Religious practice is usually done in a  group context and thus involves social relationships. These relationships can provide friendship and social support in times of emotional needs. Religious participation can have beneficial psychological effects. Religion can improve psychological health through increased self-esteem, producing a sense of belonging to the immediate religious group and an interconnection with the world, which is so lacking in modern times, and can help a young person to find meaning in life. Family participation is typical in religious activities, as distinct from other groups that family members may individually participate in (e.g., sports clubs, after school clubs, book clubs) that tend to separate people by age, sex, and personal interest. Thus, if the whole family practices the same religion, religious activities can serve to strengthen ties among family members. 3. 2.3 The choices young people make can have immediate and long-term effects on their lives. As adults and support staff we have to ensure we empower young people to make the right decisions. Children and young people can be seen as experts in their own lives; they often know what it feels like to be in their situation and to have had their personal experiences. Children and young people know something different to adults. It has ben said that adults follow paths, children explore. Treating children and young people as experts in their own lives means showing respect for what they say or communicate. This is not to say that children and young people always know what is in their best interests and they often want adults to help them make important decisions. Sometimes it is the role of adults (parents, family and professionals) to set boundaries and to identify the best course of action. Yet this needs to be done with children and young people who may know best how they feel. Some of the choices young people face making are – academic, career pathway and lifestyle choices i.e. smoking, drinking and drug taking. Children and young people with disabilities may need parents and support staff to make decisions for them if they are unable to due to their conditions. This always needs to be done in the best interests of the child and within international and local law and guidelines. Learning outcome 2 – Understand how practitioners can make a positive difference in the outcomes for children and young people 1. 2. Every child is an individual with individual needs and their own potential that they should be encouraged to develop. As support staff we should try to get to know the young people we are caring for as best as is possible to be able to achieve this. Sometimes the positive outcomes for a young person are seemingly small, but because of varying disabilities these small steps can be massive. One of the young people I am supporting has many issues with diet. I recently through much hard work encouraged him to try a new food. This addition to his diet is the first new foodstuff he has eaten in Three years. We should be constantly striving to help our young people to be all they can be through the person centered approach to caring. With the help of the multi-disciplinary team working holistically each young person can actuate to the best of their abilities. Each young person has their own care plan, which is constantly updated through the feed back from all staff supporting that YP. These care plans are in place so each member of staff is aware of the specific needs of the individual. The person centered approach to care means we are supporting and treating the individual and not the disability.

The Rwandan Genocide Violent And Very Cruel Essay

The Rwandan genocide was very violent and very cruel. Many people were killed and were raped. This war was not more than where you were born and what family you belong to. In 1918 Belgium took over Rwanda, but in 1933 the Belgians forced the Rwandans into two different categories. The Hutus and the Tutsis. Everything started just because it was easier to know where all the blacks were if they were in separate groups. The Tutsis were the minority; they were the upper class and were aristocratic. The Hutus on the other hand were peasants; they were the poorest of the poor. The Europeans brought the culture of a political ethnic dissidence to Rwanda. They took the original structure and made it very extreme, ethnic cards were given to be worn at all times. The Tutsis were privileged to everything, nice food, a good area to live in, good clothing. The Hutus on the other hand were made into a much oppressed group; they lived in slums and barely had enough food to live off of. Even thoug h the Hutus were the majority they were treated like second class, animals. In the early 1960s there was a revolution, the Hutus took over and majority would rule again. But the Tutsis were not happy. The state remained separated. Through the rest of the years going up to the early 1990 throughout that period, there was a power issue with the government used against Tutsi to maintain this Hutu power. There were thousands of Rwandan Tutsis living in exile, in one state or another, on the borderShow MoreRelatedThe Genocide Of The Rwandan Genocide1458 Words   |  6 Pages It is almost too easy to think of the Rwandan Genocide as something out of a fictional horror film, in that it almost doesn’t seem possible such atrocities could have actually occurred. Only at the cinema could murdering and dismembering the bodies of perfectly innocent citizens, many of them children, be imaginable. The story of the Rwandan Genocide is one of a great divide between the Hutu and Tutsi people. However, there was no real reason for this division to come to fruition. Th ey didn’t haveRead MoreEssay 1 Jus ad Bellum, Jus in Bello, and Jus Post Bellum are the three stages of Just War Theory.2700 Words   |  11 PagesJust War Theory plays a big role in the study of genocide, war crimes and international law. International Law is at the forefront of regulating the conduct of war. Just War is one of the theories that international law uses to dictate proper and just warfare. Therefore, if a participant of war violates a principle of Just War Theory, then that participant is subject to committing a war crime and can be tried by an international court. Genocide consists of acts committed with intent to destroyRead MoreThe Ethics And Morals Of Photographing The Suffering Of Others1856 Words   |  8 Pagesthe photojournalists themselves argue that the purpose of their photography is to spark attention, awareness, and change. The ethics of displaying photographs of suffering in the media or in exhibition lies in what these images are being used for. A very direct investigation into this idea is through the photography of Brazilian photographer Sebastià £o Salgado. Salgado, who considers himself a â€Å"social photographer,† has been highly acclaimed for his work- as well as criticized. He has created severalRead MoreArab s High Commissioner For Refugees1796 Words   |  8 Pageshave been occurring in Syria and the surrounding areas for decades, but I will be focusing on the past four years as tensions began to get worse every day. Politics and the government always seem to be the root of the problem when it comes to these violent and deadly protests and full on war. There are always two sides who don’t agree on anything, and probably will never find common ground. The two groups engaging in this civil war include supporters of President Bashar as-Assad, the president of SyriaRead MoreAnalysis Of The Hunger Games 2484 Words   |  10 Pagesraces, and nationalities throughout history. From slavery to the Holocaust to genocides around the world, dehumanization has been used to continue on ways of living and justify certain acts. Pieces of literature attesting to this treatment are great sources of proof that dehumanization has occurred throughout history. In The Hunger Games, the leaders from the Capitol showed dehumanization on a grand scale by assigning very little value to human life to the citizens of Panem. The people in power take