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n1kh1l • Mar 7, 2015

Help me for design of a simple mechanism

mechanism mechanism Hi I am trying to design a mechanism for a model engine as shown in pic. The red lever on top and a bell crank are both connected to a single crank by two connecting rods.
The travel of bell crank at free end should be 1.5 times the travel of crank and both should be 90 deg offset.
Can anyone help me to design the dimension for the mechanism?
I need to know exact point at which the bell crank fulcrum is to be located so that it gives equal sinusoidal motion above and below horizontal.
TAMIL AZHAGAR • Mar 7, 2015
You can simply divide this into four bar mechanism.
n1kh1l • Mar 7, 2015
You can simply divide this into four bar mechanism.
The engine I am trying to make is a Rider Ericsson Hot Air Pump which uses this mechanism.
I dont want to divert from original engine.
A bellcrank is a type of crank that changes motion through an angle. The angle can be any angle from 0 to 360 degrees, but 90 degrees and 180 degrees are most common.

The name comes from its first use, changing the vertical pull on a rope to a horizontal pull on the striker of a bell, used for calling staff in large houses or commercial establishments.

A typical 90 degree bellcrank consists of an "L" shaped crank pivoted where the two arms of the L meet. Moving rods (or cables or ropes) are attached to the ends of the L arms. When one is pulled, the L rotates around the pivot point, pulling on the other arm.

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