The document discusses the four bar linkage mechanism. It consists of four rigid links connected by four pin joints, forming a quadilateral. The length of one link cannot exceed the sum of the other three links. A variety of mechanisms can be formed from slight variations to the four bar linkage, including changing link proportions or combining multiple linkages. The four bar linkage is the simplest closed loop mechanism and has one degree of freedom. Inversions of the four bar linkage include the beam engine, locomotive coupling rod, and Watt's indicator mechanism. The single slider crank chain converts rotary to reciprocating motion and vice versa using one sliding and three turning pairs. Inversions include pendulum pumps, oscillating cylinder engines, and internal

1. SUBMITTED BY: SAAHIL R.
KSHATRIYA
ENROLLMENT NO.: 150120119164
BATCH: 3C1
SUBMITTED TO:
PROF. VIPAL

2. The Four Bar Chain
 It is the much preferred device for the mechanization and control of
motion due to its simplicity and versatility.
 It consists of four rigid links which are connected in the form of a
quadilateral by four-pin joints.

3. The Four Bar Chain
 It is impossible to have a four bar linkage if length of one of
the links is greater than the sum of the other three.
 A variety of useful mechanisms can be formed from a four-
link mechanism through slight variations, such as changing
the character of the pairs, proportions of links and many
complex link mechanism can be formed from combination of
two or more such four link mechanism

4. Four Bar Linkage
→ Is the simplest of all closed loop linkage
→ Have three moving link, one fixed link
and 4 pin joints
→ There is only one constraint onther
linkage, which defines a definite motion

5. Inversion of four bar chain
(quadric cycle chain)

6. Inversion of four bar chain
Beam engine (crank and lever mechanism)
 A part of the mechanism of a beam engine (also known as crank
and lever mechanism) which consists of four links, is shown in Fig.
 In this mechanism, when the crank rotates about the fixed centre A,
the lever oscillates about a fixed centre D.
 The end E of the lever CDE is connected to a piston rod which reciprocates
due to the rotation of the crank.
 In other words, the purpose of this mechanism is to convert rotary motion
into reciprocating motion.

7. Inversion of four bar chain
 Coupling rod of a locomotive (Double crank mechanism).
Watt’s indicator mechanism (Double lever
mechanism).

9. Single Slider Crank Chain
A single slider crank chain is a modification of the
basic four bar chain.
It consist of one sliding pair and three turning pairs. It
is, usually, found in reciprocating steam engine
mechanism.
This type of mechanism converts rotary motion into
reciprocating motion and vice versa.

10. Inversions of Single Slider Crank
Chain
1.Pendulum pump or Bull
engine.
2.Oscillating cylinder
engine
3.Rotary internal
combustion engine
4.Crank and slotted lever
quick return motion
mechanism.
5.Whitworth quick return
motion mechanism.

12. Inversion of double slider
mechanism
Elliptical trammels
Scotch yoke mechanism
Oldham’s coupling

13. Elliptical trammels.

14. Scotch yoke mechanism.

15. Oldham’s coupling.