Forth inversion of Four Bar Chain
Watt’s Straight Line mechanism (Double Rocker(Lever) Mechanism) :
A Watt's straight line mechanism (also known as Watt’s indicator mechanism or double lever mechanism) which consists of four links, is shown in Fig.
The four links are : fixed link at A, link AC, link CE and link BFD.
It may be noted that BF and FD form one link because these two parts have no relative motion between them.
The links CE and BFD act as levers.
The displacement of the link BFD is directly proportional to the pressure of gas or steam which acts on the indicator plunger.
Watt mechanism (Double Rocker(lever) Mechanism) :
On any small displacement of the mechanism, the tracing point E at the end of the link CE traces out approximately a straight line.
The initial position of the mechanism is shown idnoFttiegd. bliynefusll lines whereas the show the position ofthe mechanism when the gas or sptreasmsure acts on the indicator plunger.
