A knuckle joint is a type of joint which connects two cylindrical rods whose axes lies on the same plane and are under a tensile load. It is used to transmit axial tensile force.
This joint allows angular movement of the two cylindrical rods in one plane.
Knuckle joint is named so as it uses a knuckle pin to join the two cylindrical rods.
Parts of knuckle joint :-
1) Two rods which are to be connected
2) Eye end
3) Double Eye End or Fork End
6) Taper Pin or Lock Pin or Split Pin
Construction of knuckle joint and Functions of different parts :-
Knuckle joint is used to connect two rods in which one rod has one eye end and the other rod has two eye end or the fork end. This ends are named one and two eye ends as one of these has one hole and the other one has two holes.
One eye end is placed between the two eyes of the two eye end or fork end. After that a knuckle pin is inserted in the holes of the eye end and fork end. Knuckle Pin is used to hold fork end and eye end together
Some part of knuckle pin comes outside of the lowermost hole of the fork end. Knuckle pin has a small hole near its bottom. A collar and a tapper pin is used to lock the knuckle pin in the eye and fork end. The collar has two holes in it and the collar is placed in such a way that hole of knuckle pin coincides with holes of the collar and after that a tapper pin is inserted in the holes of the collar through the hole of knuckle pin. In this way a knuckle joint is formed.
Advantages of using knuckle joint :-
1) It can withstand large tensile loads.
2) It has good mechanical rigidity.
3) It can be easily dismantled and assembled.
Disadvantage of using knuckle joint :-
1) This joint cannot withstand large compressive loads.
2) Less flexible than universal joints
3) Allow movement in only one plane.
Applications of knuckle joint in different machines :-
1) In automobile a knuckle is supporting skeleton for wheel assembly.
2) Joint between link of Suspension bridge.
3) Joint between tie bar and roof trusses.
4) Tie rod joint of jib crane.
4) Chains Of bicycle
5) Wipers of vechile
6) Chain straps Of watches
7) Earth Movers