Mechanism Development - Report Example

Name Professor`s name Subject Date 1. Developing the brief Concept 1 is the chosen one. Lifting materials has been done ever since man started to use tools in his day to day activities. In the ancient times, heavy and bulky construction stones were raised high during the construction of the pyramids in southern Sudan and in Egypt. This lifting was done either using ramps or ropes. However, due to the improvement in technology, hydraulic systems and motors used in hoisting systems have made work a lot more easily everywhere especially in construction sites and in the warehouses. In this case, ropes, belts, pulleys gears and chains are critical in the development of this system. The gears are to be of different diameters and different number of teeth. The pulleys in this case will be of the same diameter. As for the ropes; the length and the strength are very important so that they do fail if they are weak. The system will have a life span of about ten years or more due to the nature of the materials used. However like every other engineering structure, maintenance in this structure is necessary. For gears, module is very important because of meshing together. Gears with different modules would not mesh[Bro]. As it is necessary for every other hoisting system, the raising platform must be cage like with lockable door for the sake of safety. The other thing is that the ropes and chains must have a factor of safety. This is to mean that the ropes and chains must be capable of supporting more weight than expected by one and half times (100kg = 981N). No ethic issues would be a constrain here other than the common ones in engineering[Bro]. 2. Mechanical analysis The cage together with the weight of the person would be approximately 110kg. This is about 1079.1N. Therefore, because the effort available is far much less that the weight to be lifted the velocity ratio should be a bit higher. The mechanical advantage (MA) = = =5.955 The pulley supporting the weight we can say it is of diameter d4 Torque =f*r Where f is the weight to be supported R is the radius of the pulley supporting the weight Torque required = r4 * 1079.1N And since the torque required to the platform and the cage is equal to the torque required to be supplied by the hands then, Torque supplied = r1* 200N Where r1 is the diameter of the pulley supporting the chain that is pulled by hands. Equating the two; 200r1=1079.1r4 = =5.3955 Assuming the system is 100% efficient, the ratio of the radius of the pulley upon which the effort is applied to the radius of cylinder upon which the load is supported is 5.3955 Because that is never true, the ratio should be higher than that. Say 6 to 7.5. Friction always makes efficiency lower than 100%. The weight of the moving parts is rarely factored in during the development. Those are some of the reasons why the efficiency is never 100%. The higher the velocity ratio the easier it is to move the load over a given distance. However, the higher the velocity ratio the greater the amount of time required to raise the load[Fal]. There are to be four ropes attached to the four corners of the raising platform for stability. The tension of each rope Tension = = =269.775N For the sake of safety the rope must exceed 269.75 N 3. Concept design The diagram below is the top view of the design it is important to note that two cantilever beams are required so that the whole lift mechanism and systems maybe hang there. The two cantilever beams are 1.5 m long and are 1 m apart. Figure 1: the top view of the hoisting mechanism with pulleys, gears belt, wall cantilever beams and axles well shown. 4. The subsystem interaction The chain sprocket will be rotated using a closed chain by hands. It is closed so that the person using to raise it can also use it when lowering down. When the sprocket is rotated, it rotates a gear which in turn rotates an idler gear. The idler gear then turns a gear which is connected to the axle. There are two axles in the system. The two axles are connected perpendicularly to the two cantilever beams 1m apart. The first axle (close to the wall) has a gear at the center. The two axles have pulleys close to the cantilever beams in the interior side of the beam. There are two cylinder drums attached to both ends of the two axles on the exterior side of the cantilever beams. To the drums, ropes are attached and are wound around when there is a rotation on the axle. The two axles are connected using belts attached to the pulleys on the axle. This ensures that when the first axle starts to rotate the other also rotates. When they rotate simultaneously, the person on the raising platform is stable and will not roll over. The belts are v shaped so that the slip can be minimized greatly. Is slip is high the stability and therefore the integrity of the entire system is compromise. 5. Component search and selection The Beams, which support the whole structure, are readily available from the store. Wood or steel section would work perfectly well. 6. Geometrical stability The two supporting cantilever beams are fixed on the wall. This was due to the assumptions that there was a single concrete wall next to the place where the raise was supposed to be. The steel sections of the cantilever are fixed to the wall using nuts and bolts. The two axle on the other hand are fixed on the cantilever beams using u bolts and nuts. The u bolts are used for easy replacement of the axles when they wear out. There is an assumption that the axles will wear off faster than the cantilever beams. However, even if the cantilever beams fail first, replacement would be easy. The first would of the rope on the drum is tied tightly. This is done by first fixing the end of the rope the drum. Adhesives in this designed system will not be used anywhere[Fal]. 7. Environmental robustness. The only materials that would be affected by the weather in the environment are the steel components. This is because the steel expands and contract during depending on the weather conditions. Dust is not likely to affect the system because lubrication would be used on the bearings o which the pulleys and gears are mounted. The lubricant would serve to trap the dust. The materials with which the ropes are made from is not affected by weather easily. However, if the steel would be exposed to water for a significant amount of time, it would rust and ware off. However high carbon steel components would withstand rusting for a long time. House the gears would work well also[Sho]. 8. Operation reliability Ropes from steel cables are strong and they rarely fail. Even though steel is affected by water which brings about rusting, the vertical position of the rope will ensure that water does not stay longer than necessary. Steel cantilever beam once fixed properly on the wall, they can work well for more than fifty years. Gears and pulleys on the other hand are made from steel. Steel even though it is heavy, its tensile strength is relatively high compared to other beams made from other materials with same geometry and dimensions. The gears and pulleys therefore have a lifespan of at least 10 years. However, the weight carried here should not exceed 200kg (1968N). 9. Serviceability The repair of the system is extremely easy and simplified. The reason is because ever material and components used are standard parts and can be easily found in the market. The assembly method is one that uses nuts and bolts. When lubricating the moving parts, the person doing it can easily access them[Wen23]. 10. Sustainability issues Steel metals used are the beam sections, gears, pulleys, and the axle can be easily casted again into other materials after wearing off. The rubber belts on the other hand would be difficult to recycle and can be reused somewhere else. The materials have low effect on the environment also because none is reacting with the atmospheric air to release poisonous compounds. Works Cited Brokenshire, Peter, and Susan Andersen. Hoist & Haul 2010: Proceedings of the International Conference on Hoisting and Haulage. Littleton, Colo: Society for Mining, Metallurgy & Exploration, 2010. Print. Falesiedi, Osvaldo. Hypothesis Concerning a 'lifting System' for Stone Blocks Used in the Building of Pyramids and Obelisks in Ancient Egypt. S.l.: Iveco, 1995. Print. [Jon], Franklin D, Holbrook L. Horton, and John A. Newell. Ingenious Mechanisms for Designers and Inventors: Mechanisms and Mechanical Movements. New York: Industrial Press, 1930. Print. Shollenberger, Carl A. An Investigation of a Two-Dimensional Propulsive Lifting System. Washington, D.C: National Aeronautics and Space Administration, 1973. Print. Wenger, Philippe. New Trends in Mechanism and Machine Science. Cham, SWITZERLAND: Springer International Publishing, 2016. Internet resource. Read More

The gears are to be of different diameters and a different number of teeth. The pulleys in this case will be of the same diameter. As for the ropes; the length and the strength are very important so that they do fail if they are weak.  The system will have a life span of about ten years or more due to the nature of the materials used. However, like every other engineering structure, maintenance in this structure is necessary. For gears, the module is very important because of meshing together. Gears with different modules would not mesh (Brokenshire 123).

As it is necessary for every other hoisting system, the raising platform must be cage-like with a lockable door for the sake of safety. The other thing is that the ropes and chains must have a factor of safety. This is to means that the ropes and chains must be capable of supporting more weight than expected by one and half times (100kg = 981N). No ethical issues would be a constrain here other than the common ones in engineering (Brokenshire 567).

The cage together with the weight of the person would be approximately 110kg. This is about 1079.1N. Therefore, because the effort available is far much less than the weight to be lifted the velocity ratio should be a bit higher. 

Assuming the system is 100% efficient, the ratio of the radius of the pulley upon which the effort is applied to the radius of the cylinder upon which the load is supported is 5.3955

Because that is never true, the ratio should be higher than that. Say 6 to 7.5.

Friction always makes efficiency lower than 100%. The weight of the moving parts is rarely factored in during the development. Those are some of the reasons why the efficiency is never 100%.

The higher the velocity ratio the easier it is to move the load over a given distance. However, the higher the velocity ratio the greater the amount of time required to raise the load (Falesiedi 34). There are to be four ropes attached to the four corners of the raising platform for stability. 

The only materials that would be affected by the weather in the environment are the steel components. This is because the steel expands and contract depending on the weather conditions. Dust is not likely to affect the system because lubrication would be used on the bearings o which the pulleys and gears are mounted. The lubricant would serve to trap the dust. The materials with which the ropes are made are not affected by weather easily. However, if the steel would be exposed to water for a significant amount of time, it would rust and wear off. However high carbon steel components would withstand rusting for a long time. House the gears would work well also (Shollenberger 98).

Ropes from steel cables are strong and they rarely fail. Even though steel is affected by water which brings about rusting, the vertical position of the rope will ensure that water does not stay longer than necessary. Steel cantilever beam once fixed properly on the wall, can work well for more than fifty years. Gears and pulleys on the other hand are made from steel. Steel even though it is heavy, its tensile strength is relatively high compared to other beams made from other materials with the same geometry and dimensions. The gears and pulleys, therefore, have a lifespan of at least 10 years. However, the weight carried here should not exceed 200kg (1968N).

The repair of the system is extremely easy and simplified. The reason is that every material and components used are standard parts and can be easily found in the market. The assembly method uses nuts and bolts. When lubricating the moving parts, the person doing it can easily access them (Wenger 86).

Steel metals used are the beam sections, gears, pulleys, and the axle can be easily cast again into other materials after wearing off.  The rubber belts on the other hand would be difficult to recycle and can be reused somewhere else. The materials have a low effect on the environment also because none is reacting with the atmospheric air to release poisonous compounds.

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