The document summarizes a presentation on selecting manufacturing methods for a knuckle joint. It introduces knuckle joints, describes their typical parts and applications. It then discusses selecting materials like steel or wrought iron and manufacturing processes like casting, fabrication or forging for the different parts. The document outlines design procedures and assumptions for stress analysis. It provides an example of designing a knuckle joint for a tractor trolley subjected to 75kN tensile load, selecting materials, dimensions and safety factors.

1. STES’s
NBN Sinhgad School of Engineering, Pune-411041
Department Of Mechanical Engineering
Subject : Design of Machine Elements-1
A Presentation
on
“Selection of manufacturing methods for Knuckle Joint”
By
Mr. Bayaskar Tejas Sanjay.
Mr. Dendge Viraj Santoshkumar.
Mr. Deshmukh Omkar Rajendra.
Mr. Pathare Kaushal Surendra.
Mr. Shukla Prathamesh Ravindra.
[2020-21]

2. Content
 Introduction
 Selection of Materials & Manufacturing
Methods
 Design Procedure
Conclusion
 References

3. Introduction of knuckle joint

4. Introduction of knuckle joint
• 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.
• Knuckle joint was inspired from Hand Knuckle movement.

5. Parts of Knuckle Joint
Taper pin
Fork end Eye end
Knuckle pin Collar

6. Parts Of Knuckle Joints
Exploded View of Knuckle Joint

7. Knuckle Joint Assembly

8. Knuckle Joint working

9. Typical applications of knuckle joints
1. Joints between the tie bars in roof trusses.
2. Joints between the links of a suspension bridge.
3. Joints in valve mechanism of a reciprocating engine.
4. Joints between the links of a bicycle chain.

10. Selection of Materials & Manufacturing Methods

11. • Material :- Process Steel or Wrought Iron
• Manufacturing process :- fork end may be cast or fabricated or forged. In the knuckle
joint illustrated, the rods are integral with the eye and fork.

12. • Material :- Process Steel or Wrought Iron
• Manufacturing process :- may be cast or fabricated or forged. In the knuckle joint
illustrated, the rods are integral with the eye and fork.
Eye end

13. • Material :- Steel or Wrought Iron
• Manufacturing process :- Split pin may be cast or fabricated or forged. The split pin is
usually a tight fit on the pin which does not allow collar to come out .
Taper Pin / Split Pin

14. • Material :- Steel or Wrought Iron
• Manufacturing process :- pin may be cast or fabricated or forged. The pin is usually a
tight fit in the eye or held to the eye with a grub screw and bearings are provided in the
fork. The bearings may be plain bearings or rolling element bearings.
Knuckle pin

15. • Material :- Steel or Wrought Iron
• Manufacturing process :- Collar may be cast or fabricated or forged. The collar is usually
a tight fit on the pin .
Taper Pin / Split Pin

16. Assumptions made for stress analysis of a
Knuckle Joint
• The rods are subjected to axial tensile force.
• The effect of stress concentration due to holes is neglected.
• The force is uniformly distributed in various parts.

17. Design of Knuckle Joints

18. Knuckle Joint Design
• d = diameter of rod
• d1 = d
• t = 1.25d
• d2 = 2d
• t1 = 0.75d
• d3 = 1.5.d
• t3 = 0.5d
• Mean diameter of the split pin = 0.25 d

19. However, failures analysis may be carried out for checking. The analyses are
shown below assuming the same materials for the rods and pins and the yield
stresses in tension, compression and shear are given by σt, σc and τ.
Failure of knuckle pin in bending (if the pin is loose in the fork) Assuming a
triangular pressure distribution on the pin, the loading on the pin is shown in
figure. Equating the maximum bending stress to tensile or compressive yield
stress we have

20. Bending of a knuckle pin
The design may be
carried out using the
empirical proportions
and then the
analytical relations
may be used as
checks.

21. Design a Knucle Joint for Tractor Trolly joint, when it is
subjected to 75 kN tensile load.
I. Selection of material
• The rods are subjected to tensile force.
• Therefore, yield strength is the criterion for the selection of the pin. On strength basis, the material for two rods and pin is
selected as plain carbon steel of grade 30C8 (Syt= 400 N/mm2).
• It is further assumed that the yield strength in compression is equal to yield strength in tension.
• In practice, the compressive strength in tension.
• In practice, the compressive strength of steel is much higher than its tensile strength.
II. Selection of factor of safety
• In stress analysis of knuckle joint, the effect of stress concentration is neglected.
• To account for this effect, a higher factor of safety of 5 is assumed in present design.

22. III. Calculation of dimensions
Sr. No Symbol Specifications Calculated Value
1 Syt Yield tensile strength 400 N/mm^2
2 ot Tensile stress 80 N/mm^2
3 oc Compressive stress 80 N/mm^2
4 v Shear stress 40 N/mm^2
5 D Diameter of rod 36 mm
6 D1 Enlarged diameter of rod 40 mm
7 a Thickness of fork 28 mm
8 b Thickness of eye 46 mm
9 ds Diameter of knuckle pin considering shear failure 36 mm
10 db Diameter of knuckle pin considering bending failure 44 mm
11 d1 Diameter of knuckle pin head 66 mm
12 fs Factor of safety 5
13 Syc Yield compressive strength 400 N/mm^2
14 Sys Yield shear strength 220 N/mm^2
15 p Tensile force 75 KN
16 do Outside diameter of fork/eye 88 mm

23. Conclusion
• Hence we have designed the knuckle joint.

24. Reference
1. V B Bhandari, [1994] , “Design of
Machine Elements” , McGraw Hill Education (India) Pvt Ltd.
2. V B Bhandari, [2014] , “ Machine Design Data Book “ , McGraw Hill Education (India) Pvt Ltd.

25. THANK YOU