 Hello students, myself Siddhaswara B. Tulsapure, Associate Professor, Department of Mechanical Engineering, Walchand Institute of Technology, Solapur. So, in this session, we are going to deal with synchronizing circuit, the learning outcome. At the end of this session, students will be able to draw synchronizing circuit and explain its working. The contents are, firstly we will have introduction, then we will go for different methods of obtaining synchronization, then synchronizing circuit and lastly the references. Let us first start with the word it is synchronization. What synchronization means? So, when we are having the word synchronization, so more than one operation or activity, these are going to come into picture. So, synchronization refers to the operation or activity of two or more things at the same time or at the same rate it is. So, we are having two that is at the same time or at the same rate it is. Say two or more operations we are having or two or more activities we are having. Next to that one, the need of synchronization in case of the hydraulic actuators may be due to different reasons. One of them say for example, if we take for the clamping operation, suppose we are making use of the two cylinders for the more forces and say more force for the clamping, these two pistons of the two linear actuators, they should move with the say in a synchronized fashion. So, one should not move ahead and one should not be on the say it is following the first one. So, like that it should not be. So, in case of that one or any other specific process requirements we may have where even not two, we can have even more number of the actuators and they are having the say the pistons of those should move in the synchronized fashion. So, like that we may have certain process requirements etcetera. So, in case of those, so how that synchronization can be achieved so that we can think of. Now, presently consider just simple say two linear actuators we have gone for and then the say 4 by 2 direction control wall we are having say P is connected to a supply to the two cap ends it is at the same time. Pistons of these two they are going to move and the oil from the rod end side again it is coming through the common pipe to the say port B and B is connected to T. Now what you have to think of is whether the movements of the two linear actuators are synchronized or not. That is the pistons of these two cylinders whether they are going to move at the same time with the same say rate of movement so that at any time if we check the position of this one and this one the both are going to be exactly at the same position suppose at the middle and if we take the time for that middle position the time should be required it is same etcetera. So, like that you can think of so the synchronized movement it whether we are going to get with the help of this arrangement or not that you have to think of. So, it is applied to both the cylinders cap end at the same time and the oil returning from the rod end it is taken to the port B through a common pipe just after some initial connections. Supply is also through common pipe, but later on slide say connections these are going to be to the two cylinders or two cap ends see the answer is no actually. See what happens there are number of factors which are controlling the movement of the actuators or the say the pistons in case of these linear actuators. Now we are having one it is the pipe length say the common pipe it is ok, but from there one pipe goes to the cap end of the one cylinder and another goes to the cap end of the another cylinder. So, the length of these it is going to matter the friction of oil and say the inner surface of the pipe it is going to matter friction between the oil and the inner surface of the cylinders it is going to matter because two cylinders are there again and unequal flow to some extent it may also be there. So, exactly 50-50 percent of the oil will not go to the two cylinders in case of that one also the difference it is going to occur. So, one piston it is capable of moving ahead and the second one it is going to follow to some extent. So, like that the things are going to be so these are not the synchronized movements actually. So, what we can have is different methods can be used for the synchronization. So, one of the methods it is say mechanical clamping. The second one is also referring to the say mechanical coupling first one and the second one it refers to the say mechanical means only, but with the help of the rack and pinion arrangement. Third one it is actually you can call it as a synchronization circuit or synchronizing circuit. So, it is by making use of the flow divider it is one by one we are going to deal with say the first one we will consider. So, it is the synchronizing circuit by making use of the mechanical coupling. See what we have done. We have say taken the end of this first piston rod and the end of this second piston rod to the one plate which is fixed here to these two piston rods by some say screw and nut etcetera. So, you are having these two piston rods fixed to a single plate means even though number of factors are there which are leading to the difference in the piston positions or the speed of the piston positions speed of the pistons etcetera. So, what is happening is if the one piston is moving so it is taking along with this plate and this plate is again fixed to the another piston rod end so the second piston is also going to move. So, like that we are having the mechanical coupling between the two piston rods and the two pistons these are piston movements these are now in a synchronized fashion. So, this is the simplest type we are having this is a low cost system. But we have no changes in the say earlier simple circuit which we dealt say and the synchronization was not there just what we have done is we have used some mechanical means for that synchronization. So, that is what we have done here. Next the precise movement if you are needed or precise synchronization if it is needed what further you can do is we can go for instead of that plate which is attached at the end of the piston rod say you can go for the rack and pinion arrangement. So, one piston so it is at the end of this we are going to have the rack say this rack is meshing with one pinion pinion is mounted on a shaft on the same shaft we are having one more pinion and this pinion is meshing with the rack which is attached to the end of the another piston rod. So, we are having the pinion specification same the rack specification same. So, here what will happen is if one piston is moving ahead so the sequence how it is taking place the motion of one rack it is going to take place then the corresponding mesh the pinion it is going to rotate the pinion is mounted on the shaft so shaft is going to rotate the shaft will give motion to that say second pinion also so because it is mounted on that one. So, that pinion gives lastly the motion to the rack so second rack is also moving you can observe that it was started with the first rack and it has ended with the second rack. So, we are having both the racks moving at the same time so that is what the synchronization we have achieved using the rack and pinion. The last one it is you can say actually call it as a synchronization circuit because here mechanical means we are not using and we are going to make use of this some walls which say it is called as flow divider. Now see here the we are having that 4 by 3 direction control wall here the middle position of this pool we have shown here then we are going for the common pipe or the common working line from here it goes to this flow divider or you can say it is say together flow divider it is flow control wall through this one it is going to the second end of one cylinder and through this one it is going to the second cylinder. So, now we might have some differences in the resisting loads here and here say one is doing the say one operation and the second one is doing another operation you can consider the different operations which are occurring in the industries say now these two may be totally different operations and the resisting loads may be totally different. So, in those situations what might happen is if the load resistance it is more here or here it is say where the resistance it is lesser that piston it is going to move faster so that is what is going to happen if we are restricting ourselves to the use of this one only that is this flow control walls because the flow control wall so it is not pressure compensated here and we are having the flow through this one based on the pressure difference and between the inlet and the outlet and the pressure difference across this flow control wall it is dependent upon the resisting load that is what we are having now here what you can do is you can go for the use of the check walls here. So, the check walls here and here you can observe and we are going to have the use of the two check walls here. So, these two check walls will allow us to have the movement of the these two pistons independent of the resisting loads and the excess flow from one of the say cylinders where the resisting load is lesser will be diverted to the second cylinder and the second cylinder it is going to move in a synchronized fashion with the first cylinder. So, like that what we are having is with the help of the flow divider we are having the synchronization of the two pistons. So, three different say synchronization methods we have seen firstly by mechanical coupling the second one was also mechanical that is by making use of the rack and pinion type of the arrangement and the third one is actually the synchronization circuit where we are gone for the use of the flow divider it is. So, we will stop here these are the references thank you.