Transcript

Welcome to the Lecture 2 of Week 2. We have discussed the purposeful or the functional aspects in the first lecture. In this lecture I will discuss about the operational aspects. What are the operational aspects, I have given you an introduction in the first lecture. Operational aspects implies the ease to use or the easiness to operate the product. I have the taken the word ‘ergonomics’ here. When we talk about operational aspects the word ‘ergonomics comes into play.

So what is ergonomics. Ergo means human and nomos means rules. So the rules concerning human comfort is known as ergonomics. So when I say the dimension of the pencil. This is around 8 to 10 mm. because the sensitivity that fingers could have, do very sensitive or very accurate work. Hands on and very accurate control. For a lesser accuracy we can this; palm control. If you need to write on a whiteboard, a broader pen is used that is around 25 mm in diameter. This is around 10 mm diameter. So these are the ergonomical designs. Height of the chair that you sit on. The desk that I am standing on. That all are design. When we design the vehicles, the tractor, the control, where would the steering, all the things. I will just have a brief discussion about those aspects in this lecture.

Easy to use, easy to handle is the rule in ergonomics. So in ergonomics subjected to varying degrees of skilled or potential operators, and adaptable to various operational conditions, the product should be designed. The problem of designer becomes all more critical here, because the trend is rising of increased versatility because of characteristics, those employees using the basic attachments as elements for building combinations, that is suitable for special purposes. For instance they have installed a foot operated pedal here. So this is the design that is made. A foot operated pedal for threshing of the crops here. So this is the rice that is being threshed here. A foot operated pedal is doing this work.

Certain rules of Ergonomics. In ergonomics the controls that we use should be within our range, within our reach. When I say controls, controls mean physical controls. When I say controls, these are the controls. Button. This is a button. This is a pedal. This is a switch. This is also known as toggle switch. These are known as controls. These are also given; knob, crank, wheel, lever, pedal. These three are rotary controls. Lever and pedal are linear controls. If we need to control something using the fingers as I said, the accuracy would be higher. So in case of knob that is operated by hand I will put A for accuracy, S for speed, and F for force.

So in this case the force required to operate this machine manually without any external source of energy or electricity. That was higher. So that is why foot pedal was suggested. So in this case a foot pedal the force is higher. So this means high. This low arrow means low. In case of button we have high speed, speed is too high. In case of pedal, the force is high. High force can be employed here, but the accuracy is lower. In case of switches both speed and accuracy are higher. Right in case of knob, accuracy is higher, speed is higher but the force is lower. So what happens when we employ more force, we use wheel. In the case of wheel the force is higher. And the speed is higher but lower than what we have in knob.

So these are different kinds of control, like in crank, wheel; different kinds of control is used, crank and wheel. Prof Ram Kumar showed in one of the implements, gave a use case analysis in the previous lecture. For different kinds of controls are there. Other than this considerations like the normal and the maximum working area. The normal working area. In that we have the controls, those which are to be used very frequently. Like you consider the driving of the tractor. Steering wheel you have to use all the time and the horn button is there just close to your thumb. That has to be used frequently multiple times. The speed has to be higher in that case. In case of gear; gear could be kept at a reachable distance. That is known as maximum working area. Kept at a reachable distance, but you just change the gear after a certain time. The frequency is not that high there.

So in that case, suppose if here is the operator. I am taking the top view. This is the normal working area. This is the maximum working area. Then this is the total arm length. This is around 0.8 x arm length. Normal working area, like this is my normal working area, when I am moving my hand like this. This is my normal working area. This is maximum working area. So anything that has to be used for a maximum frequency or high frequency, that could be put in normal working area. We just have to do it multiple times. And those things that are to be used rarely could be put in a reachable but maximum working area.

And other things that you have to very rarely use. Once in a while. Those can be, you can take one step forward, and just pick and bring that thing close to you. So in this way, the workplace is designed and the equipment also is designed using the same phenomena. You see a few ergonomic designs regarding the shape. These are the incorrect ones, these are the correct ones. You see this is handsaw. Hacksaw we call it. Hacksaw or handhacksaw. This is our plier, and this is hammer. So better ergonomical design for the hands would be this. In place of holding it straight or horizontal exactly, this is a better design. In case of plier this is a better design. In case of hammer this is a better design.

Why is this so? Because the human body would like to come into its natural state. Everything likes to come into equilibrium. So anything we need to pull, we design it in a way that. From left hand side we pull it to the right hand side. High force has to be applied from the right hand side. So the things likes to come to its equilibrium state. That is why also for transporting the material like in case of thresher, we use gravity. The crops or the grains fall, while making the use of gravity into the bins or the bags we collect them.

So these are the rules of ergonomics which we employ. The certain rules suggested by ILO. ILO that is International Labor Organization. We will provide you link to this and you can read regarding the rules of designing the workplace layout or used for the designing the equipment or various kinds of controls that are use. This you can read if you like, to have more information on operational aspects.

Thank You.