 Hello friends. Myself, NS Kartikar, Assistant Professor Department of Mechanical Engineering, Valachandha Institute of Technology, Solapuram. Now we are going to discuss about the freehand sketches and one of the subgroup of mechanical elements coupling joints. At the end of this session, student will be able to understand the need and importance of freehand sketches. The student will be able to draw and apply the coupling joints in real time. Let us see the content of this presentation. The content will flow like this. Initially, we will see the introduction about the freehand sketches along with the particularly couplings, then need of freehand sketches, types of coupling joints and many more. Let us see the initially the machine drawing and its relevance or importance of freehand sketches in the same. As we know, the engineering graphics rather the drawing, rather machine drawing is one of the important communication language of an engineer. It is also going to be called that mother tongue of an engineer. Through the means of sketches and drawings, the engineer is going to express their concept, designs and many more things to the third person. Now we know that various kinds of drawings are there in our machine drawing, that is production drawing, assembly drawing and many more drawings applications also. All these drawings are going to be generated through the means of manual efforts rather the human skills as well as through the means of computer graphics software. Now many other times it is required to go with the drawing rather it would be called as a sketch, that is drawing or generating the sketch with the means of non-availability of the various drawing instruments. Various conditions are there where it is not allowed to use the drawing instruments. We are going to enforce to express the drawing with the means of pen, pencil, eraser and restricted to that only. So here truly the human efforts and skills regarding the drawings are going to be useful and required to be shown for expressing their particular ideas and concepts. It is also going to be used for the effective communication for various concept, technical concept from one person to the another person. Now let us go with the coupling joints. Under the mechanical elements one of the important subgroup of elements that is the coupling joints. What and where the couplings are nothing but it is an intermediate member which connects the two distinct ends of the shaft. Now the shafts may be required to connect each other to transmit the rotary motion or linear motion. For rotary motion couplings are basically used for the particularly maybe circular or round kind of cross sectional shafts. Now particularly coupling joints are going to be used for showing in many of the assembly drawings. Now at the particular moment you require to generate the particularly coupling drawings that can be done with the means of remembering what exactly the coupling means. That is our next question understanding how it works, what are the applications of the same depending on that we have to remember the couplings. This is the only one of the method with which we can produce the particularly drawing in the form of sketch with this such kind of knowledge. Now let us go with the particularly at this stage of this session. Are you able to recall share some of the applications for coupling joints which you had used earlier in the drawing or sketching of any academic subjects. Try to recall have you seen the couplings anywhere which are the possible types if you know try to just enlist yes. Now let us try to compare your list with the further whatever the type we are learning. Let us go with the first type but muff coupling. Now here look at to the cursor point. Now while drawing the freehand sketches of the coupling means what possibly many a times it is required to be only restricted to orthographic projection. This is the front view may be fully cross sectional this is the side view and this is the quarter sectional particularly isometric view. Now that is depending on the certain situations that how you require to go with the either 2D, 3D isometric or many more modes. According to that freehand sketch skill is required to be acquired and to be upgraded. Now let us see here try to understood the type of couplings remembering the same and it will be only beneficial way to reproduce in the form of freehand sketches. But muff coupling what do you mean by the but joint is the two abutting surfaces of the shafts are touching to each other and muff means it is covered covered with a particular piece of a metal which is indirectly we can say that the hollow piece kind of a pipe this is called as the muff. Now these two ends of the shafts are touch to each other and the keys is introduced from both of its end. Now you can see very well this is the these are the two shafts this is the muff and this is the side view and the hatched portion is nothing but in the side view represent the shaft. This is the standard method for engaging the particularly couplings. Coupling element is going to be engaged with the shaft with the means of keys. Let us go with the further more types this is another one half lap muff coupling. Now you can see that in previous type the end surfaces of shafts are directly touching to each other but here the shaft is cut to both of its end both ends of the shaft and these are overlapping one with the other. This is added advantage which will be we are getting for further confirmation of you can say that co-linearity of the two distinct shaft elements. Now this will ensure that some little bit more efficient thick way for particularly power transmission. Difference between this and previous is this is the half lap muff coupling means shaft end is cut to the half of its diameter. Let us go with the further more type split muff coupling. Many a times you required to be remove or engage or disengage the couplings for the same the couplings are split into the two halves it will be very well aware with the isometric sectional view this is the upper half and lower half. We can see in the side view this is the upper half and this is lower half. The muff is cut into the two halves and this is overlapping the two ends of the shaft and with the means of nut end bolts this is one of the pair nut end bolts you can visualize and here you can see and opposite end one of the nut bolt one of the nut bolt will be there which will be confirming the thorough engagement of the coupling over the ends of the shaft. This will further help out for easy engagement and disengagement of the couplings. This is another one this is these are the most popular and standard methods of the couplings. This is the flanged coupling you can say that flanged means flange element is there the disc like element you can see in the isometric view which is quarter sectional removed part. So this is one of the particularly flange another flange. So one each flange is going to be engaged over the end of the shaft by the means of key and these two flanges are joined together with the means of nut end bolts. So likewise this is the joint is confirmed the particularly there are 4, 6, 8 number of nut end bolts which are in even number and obviously you can see a minute detail that key is engaged to one of the flange and shaft at position this particular position and another shaft and another flange is engaged with the key position exactly at least 90 degree apart. This will further ensuring the increasing the life of the key itself. Now there are some different types of flanged coupling over here. This is another one protected flange coupling. Now as this is the use for rotary shaft engagements you can imagine that the ends of the nut bolts rather the heads of the nut bolts may produce some kind of harm to the particularly operator or human being. So to cover up these rotary sharp edges we are going to introduce the covering of the same that is by the means of protected flange coupling. It is the same as like previous but it is covered to the heads of nut end bolts. This is the solid flange coupling. Many other times the flange is not required to engage the two ends of the shaft. The shaft itself is formed deformed into the flange of course to the its ends only. The shaft ends are going to be particularly molded into the flange form and directly these two ends of the shaft which are flanged forms are engaged together. This is another one bush type of flange coupling. It is a flanged protected type only but only bush is added. What is the bush specialty over here? The bush specialty is nothing but it is a particularly flexible material and it may allow little bit kind of clay and little bit kind of non-linearity. This is the added advantage of the same. This is the universal coupling. So you can imagine that one is IA and another is 4K and one pin is introduced. This pin because of this pin the particularly non-colinear shafts can be little bit accepted over here for power transmission. This is another one old ham coupling. Now here many other times we require to engage the two distinct shafts which are parallel to each other. For the same the old ham coupling type can be used. The references for this particular presentations are as follows. Thank you.