Initial Calculations, Lever Component Specification - Essay Example

Component Assignment Word Count 500 (6 pages) I. Introduction Here what will be attempted to have been designed is a lever which is able to pull apart car parts. Basically, according to the drawing, points A and B are struts. These struts rotate around the pin-joints. The pin-joints are A and B. The other components include B, O, and C, which work together. What will be attempted to be accomplished is to note how the different forces react with each other and what are the proper measurements to be able to ensure that the lever works effectively. “Mechanical advantage of [the] hydraulic press is increased by applying forces…by means of a lever.”1 Basically, here is a little bit of history with regard to why hydraulic levers came into being. “Hydraulic systems eventually eliminated cables and levers that required constant adjustment as cables stretched, rods and pins wore and brake shoes or pads wore down.”2 Hydraulic levers, therefore, were a marvel of modern engineering technology, and that is why this particular component is so important. The purpose of hydraulics are to be able to implement a specific design that has been put into place in order to aid in lifting or moving objects. In this particular specification, car parts are being separated—which requires a great deal of force, shown in kN (kilonewtons). One-thousand Newtons (a kilonewton) is equal to 0.112 tons. “A hydraulic…machine is [usually] designed to exert a maximum load…”3 The way that the lever is operated has to do with the size and direction of the force. The calculations for deducting the vector will also be analyzed and shown, included with the Detail Drawing and the Calculations. Of course, the pistons play an integral role too as well, causing the lever to either increase or reduce in speed (acceleration) accordingly. “[M]ovement via the lever and hydraulic actuator causes the power piston to move downward which in turn reduces the…opening[,] therefore reducing…speed. The reverse happens when…speed decreases.”4 It is hoped that the following information in subsequent sections—as delineated below in the thesis—will aid in understanding how this lever should summarily be constructed and implemented in order to function properly. In this report, we will analyze several elements: initial calculations; the lever component specification; a summary; design calculations; description; manufacturing techniques; methods of assembly; component features; surface treatment; and finally, a graphical communication will be provided, drawn by hand, since there were technical difficulties in utilizing Pro/E. II. Initial Calculations Calculations were completed mainly by using advanced concepts and mathematical equations in both areas of geometry, calculus, and physics. For example, in parts where one needed to find various lengths, the sine of varying degrees were taken in order to calculate the opposite divided by the hypotenuse of triangles. This is where geometry came in, because basically one had to use proofs in order to ensure that congruency proved that different corners were 90-degree angles, and that angles opposite each other (vertical angles) had the same numeric value. Also, another calculation that was made—using physics this time—included the necessity to find out how much force was being applied outward. It was calculated that 181.3 kilonewtons (or approximately 20 tons) of force was being exerted outward by one side of the lever. The force would be equal on both sides of the lever—which would act in the motions in reverse of a pair of scissors’ movement. Physics also aided in the calculations, as we were able to calculate the tolerance by the equation Center Distance (Cp) = T/3σ. The standard deviation for the center-to-center distance would equal approximately three-tenths of a millimeter. So, the resulting equation would be the center distance (43 millimeters as stated in the problem), multiplied by 3, multiplied by 0.03. This would result in a Tolerance of 3.87 m (millimeters). As is demonstrated through these calculations, “[h]ydraulic levers can be used to demonstrate Pascals Law. Pressure equals force divided by the sectional area it acts on. Similarly, force equals pressure multiplied by area.”5 This is called Tolerance Analysis. Tolerance analysis seeks to find out the aseembly’s ability to reach a quality goal that functions. Usually in tolerance analysis, one divides the tolerance by 4 in order to get a result which basically means that will give us a standard deviation (in this case it would be 0.968 mm. Of course, we rounded up from 0.9675, because it is better to have a slightly larger bushing than one that is too small which will match the tolerance. This is duly noted, as size does matter. III. Lever Component Specification The lever component specs would be as follows. For whatever size, the tolerance for width would be plus or minus about 0.25 millimeters. So, the fact that we have deduced 0.968 from 0.9675 is fine because we are only off by about five one-thousandths of a millimeter. That is coming about as closet one can get in terms of tolerances. Since the hydraulic cylinder applies the load, P, of 42 kilonewtons (kN) in order to force the panels apart, we were able to make the specs of the lever adequately suited to fit the overall design. For example, the bushing dimension that was selected would have been 45, with an outside diameter of 50—taking into account the fact that these are specified according to the specs as provided by the SKF composite dry sliding bushings charts, which indicated sizes and so forth. Without a doubt, these are important components. IV. Summary In summary, what was done was making sure that pivot point O had dimensions that were adequately secured to be able to make the levers pivot. Since the pin at point O would utilize the appropriate material, the yield strength being taken into account—what was most important was determining the height of the centre-line, which helped to calculate the tolerance analysis. V. Design Calculations A. Stress Analysis The stress analysis was calculated in the section that dealt with the initial calculations, especially important when dealing with tolerance. B. Design Procedures The way that this lever was designed was taking into account all of the necessary dimensions, especially those on the SKF site, and then ensuring that all the appropriate pieces were fit to spec. C. Description of the Final Design and Assembly The final design was developed with the tolerance analysis in mind. Of course, knowing the tolerance helped one be able to ensure that all of the pieces would fit appropriately and have the right strengths for the job that needed to be completed. The assembly would probably have to be conducted in some sort of plant that would manufacture such a large apparatus like the lever that has heretofore been described. VI. Description A. Final Design The final design of the lever depended heavily upon the specifications of each piece being correct. The SKF site helped greatly in the way of deciding what Glycodor bearings to utilize for the lever. The design was completed in such a way that it would be able to efficiently operate, and function in the manner for which it was designed. Various manufacturing techniques will have been utilized, which will be discussed more in the manufacturing section. B. Assembly The assembly of the lever would have to take place in some sort of large plant, where the pivots could be appropriately connected with bushings, washers (if necessary), and then be conjoined in their various corollary pieces—including the two scissor-like levers. C. Material Choice SKF composite dry sliding bushings were basically created by having been molded into the shape of rolls. Not only that, but they have joints which extend over the width of the apparatus. The bushings themselves were made out of M material. Additionally, there are special places in the bushings which can catch any type of grease that may fall off of the apparatus. The surfaces of the sheet metal steel backing are plated with tin that has been electrolytically treated. D. Manufacturing Techniques The way the different pieces are manufactured is important. The SKF composite dry sliding bushings are basically made of M material. They are designed to have at least one lubrication hole in each, with specific dimensions, the hole being placed in the center at 45 degrees plus or minus 5 degrees to the butt joint. The actual lever is probably going to be manufactured out of some type of recombinant metals. The lever would be made out of various types of metals, because using pure steel alone would not be strong enough. E. Methods of Assembly The methods of assembly include having to take the lever components to a plant of some sort and having each piece fitted together so that they can work in unison. Without a doubt, having found the right specs and bearings for this lever will have helped immensely. F. Component Features The component features include the bearings, the bushings, the pistons, the levers, and any other smaller pieces which might be added. G. Surface Treatment The surface was treated with recombinant steel and various lacquers. VII. Graphical Communications Fig. 1. Design Drawing and Calculations. WORKS CITED Bennett, Sean. Heavy Duty Truck Systems. US: Delmar, Cengage Learning, 2010. Pp. 352. Gentle, Richard, et al. Mechanical Engineering Systems. US: Newnes, 2001. Pp. 134. Metcalfe, Peter, et al. Engineering Studies: Year 11. US: Pascal Press, 2006. Pp. 108. Nagrath, I.J. Control Systems Engineering. Delhi, India: New Age International, 2006. Pp. 176. Vashist, Devendra. Mechanical Engineering: Fundamentals. New Delhi, India: I.K. International Pvt. Ltd., 2010. Pp. 151. Read More