Knuckle joint silde

knuckle joint (Bhupendra dewangan) facebook on like it share it

1. Welcome

2. Bharti college of polytechnic ,Durg (C.G) Affiliated by Chhattisgarh swami Vivekananda Technical University,Bhilai (C.G) A Synopsis on “Design and preparation of knuckle joint” Bharti college of polytechnic, Durg (C.G) Is Partial fulfillment of the requirement for the degree of Diploma In Mechanical engineering Submitted by Under Guidance of Bhupendra dewangan Mr. Shailesh kushwaha Tikesh dewangan Assit . Prof. of mech. Department Satyendra verma Bharti college of polytechnic,Durg Mulchand sahu

3. Introduction of knuckle joint Part of knuckle joint calculation Application of knuckle joint Advantage of knuckle joint Disadvantage of knuckle joint Content:-

4. A  knuckle joint  is a mechanical joint used to connect two rods which are under a tensile load, when there is a requirement of small amount of flexibility, or angular moment is necessary. There is always axial or linear line of action of load. Introduction of Knuckle joint

5. A typical knuckle joint has the following parts: Fork end Eye end Knuckle pin Collar Taper pin Parts of a Knuckle Joint:

6. Calculation:-   As seen in the assembly the Knuckle joint has main four parts Rods {Which are to be connected by joint } Single eye {Modified rod for assembly} Double eye or Forked end {Modified rod for assembly} Pin {Connects the two rods} Collar {to keep the pin in position} Split pin or taper pin

7. Notations used in design : P  =  Tension in rod ( Load on the joint) D =  Diameter of rod D 1 = Enlarged diameter of rod d = Diameter of pin d 1  = Diameter of pin head d  = Outer diameter of eye or fork t1 = thickness of eye end  t2= thickness of forked end (double eye) x= distance of the Centre of fork radius R from the eye 

8. STEPS TO DESIGN KNUCKLE JOINT  Step 1 : Design of Rods (D,D 1 ) Tensile failure of rod  Using basic strength equation Load = Stress * Area

9. Empirical relations Using Empirical relations the enlarged diameter of rod D 1  is determined Step 2 : Decide the thickness of eye end and forked end (t 1 ,t 2 ) Empirical relations Both these dimensions are decided on the basis of empirical relations, t 1 = 1.25 D    and    t 2 = 0.75 D

10. Step 3 : Decide the dimensions of pin (d,d 1 ) Double shear Failure The pin may get sheared off into three pieces as shown below, since the pin breaks at two places it is called double shear. Both areas are taken as resisting areas. Using basic strength equation Load = Stress * Area

11. Bending failure of pin The diameter on the basis of bending is determined using the following formula,          …..Calculate d from this formula Empirical relation for pin head diameter Since pin head is not subjected to any stress, its diameter is simply decided on the basis of proportionality, (it is taken 50% more than that of pin diameter ) d 1 =1.5 d Step 4 : Check Stresses in Eye end  Empirical relation for outside diameter of eye and fork d =2d Tensile failure of eye end The single eye may fail in tension as shown below { please note that when the plane of failure is perpendicular to the direction of force then the failure is either tensile or compressive}  

12. Step 4 : Check Stresses in Eye end  Empirical relation for outside diameter of eye and fork d =2d Tensile failure of eye end The single eye may fail in tension as shown below { please note that when the plane of failure is perpendicular to the direction of force then the failure is either tensile or compressive} Using the basic equation for stress

13. Shear failure of eye end The single eye may fail in shear as shown below { please note that when the plane of failure is parallel to the direction of force then the failure is Shear failure} Using the basic equation for stress simplifying this equation we get             Using this equation find the value of     and check if it is less than allowable value for design to be safe

14. Crushing Failure of eye end The single eye is also subjected to Crushing between pin and inner face of single eye. In case of crushing failure since the area is curved we take the projected (area which would be visible in drawing) of the cylindrical area. As we know that a cylinder appears as a rectangle in projection, hence the area will be diameter times the height of cylinder. This area is illustrated below Using the basic equation for stress ………….Using this equation find the value of   and check if it is less than allowable value for design to be safe.

15. Step 5 : Check Stresses fork end Fork end is also subjected to same failures as that of eye end, the only difference is that it has two eyes. So we get the same equations except multiplied by 2. The equations for tensile, shear and crushing failures are given below Tensile failure of  fork end                  {see the changes highlighted in red from the equation of single eye} Get the value of induced tensile stress from this equation and confirm that it is below allowable tensile stress. Shear failure of  fork end                  {see the changes highlighted in red from the equation of single eye} Get the value of induced shear stress from this equation and confirm that it is below allowable shear stress.

16. Application of knuckle joint

17. Knuckle joint can withstand large tensile loads. It has good mechanical rigidity. It is easy to manufacture and set up. It can be easily dismantled and assembled. Design is simple and easy. Advantage:-

18. The joint cannot withstand large compressive loads. It permits angular movement in only one plane. It is not as flexible as universal joint. Disadvantage:-

19. Thank you