4 bar linkage assign (1)
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dr.sami assignmentTRANSCRIPT
7/17/2019 4 Bar Linkage Assign (1)
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Name: Saad Munir Batch: ME-04A Registration No: 1922
Four Bar linkage:
A link is a rigid body which has at least two points of attachment (nodes) to make joints. A
binary link has two nodes. I have used four binary links to make a 4 bar linkage that has one
degree of freedom. The linkage has 4 components; the crank which is the driving bar to which
motor is connected, the rocker which is the driven bar, the coupler which is the connecting rod
between the crank and the rocker; and finally, the frame which is a fixed bar to which crank and
rocker are connected through pin joints. The original dimensions are frame of length 460mm,
crank of L = 240mm, coupler of L = 420mm and rocker of L = 320mm.
Originally, the crank rotates complete 360 degree and rocker remains above the frame but
rotates less than 180 degree. All comparisions below are made with respect to original.
Observation of Doubling the original crank length ( L= 480mm): Crank and Rocker are
interchanged.
Frame
Rocker
Coupler
Crank
New
ocker
New crank
Original Design
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Observation of halving the original crank length ( L= 120mm): Crank and rocker remain the
same, but, rotation of rocker considerably decreased (swings less).
Observation of doubling the original coupler length ( L= 820mm): Original Crank and rocker
interchanged. Less than 180 degree rotation of crank and lesser rotation of rocker too.
Observation of halving the original coupler length ( L= 210mm): Original crank and rocker
remain the same. Rotation of crank less than 180 degree. Decreased rotation of rocker too
and now the angle of rotation for rocker lays downwards the frame.
Observation of doubling the original rocker length ( L= 640mm): Angle of rotation for rocker is
decreased and the minimum angle of rocker with frame becomes almost zero degree.
New
rocker
New crank
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Observation of halving the original rocker length ( L= 160mm): Original crank and rocker
interchanged. Lesser rotation of the new rocker compared to as was in original.
Observation of increasing the original frame length ( L= 800mm): Original crank and rocker
remain the same. Crank doesn’t rotate even 180 degrees. Considerable decrease in the
rotation of rocker as well. Rocker goes a little below the frame too.
Observation of halving the original frame length ( L= 230mm):Original crank and rocker
remain the same. Crank rotates little less than 360 degrees. There is an increase in the angle
of rotation for rocker. Rocker now goes considerably below the frame as well
New crank
New
ocker