Geared Four-Bar Kinematic-Chain

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Geared Four-Bar Kinematic-Chain

Geared Four-Bar Mechanisms

Geared Four-bar mechanisms are usually built with:

A Four-bar Mechanism - with at least one Part that rotates continuously

One or Two Gear-Pairs

The input gear is usually fixed to the Coupler, at the distal (moving) end of the Crank or the Rocker

The center of the driven Geared-Rocker is usually at the grounded Joint of the Crank or the Rocker

Geared four-bar mechanisms are often used as 'Function Generators'. Function-Generators provide an input to output motion relationship.

Summary of Geared Four-bar Mechanisms

Gears - Four-bar Regressive

Four-Bar Regressive Gearing.

Output is co-axial with Crank center.

Four-Bar with Irresgressive Gears

Four-Bar Ir-Regressive Gearing

Output is co-axial with Rocker Pivot

Four-Bar Function-Generation with Two Gear-Pairs.

Output is co-axial with Rocker Pivot


One Gear-Pair

tog_minus        'Regressive' Geared Four-bar

tog_minus        'Ir-regressive' Geared Four-bar

Two Gear-Pairs

Four-bars with two Gear-Pairs have one idler. Usually, the two 'center gears' are edited so that they have the same module and number-of-teeth. Although, this is not necessary.

There is a small complexity that you must consider when we add the second Gear-Pair.

tog_minus        Add Gear-Pair 1

tog_minus        Add Gear-Pair 2