Model 37: stepping belt mechanism

Kinematic scheme:

Explanation:

The sun gear of the planetary gear pair (centre A₀, radius R₀) is fixed to the frame. The point B lies on the rolling circle of the planet gear (centre A, radius R₀/2) and moves along a straight horizontal line through A₀. A belt pulley (centre B, radius R₀) is rigidly attached to the planet wheel. The contact point between the pulley and the belt, guided by pulleys at C₀ and D₀, moves by superposition of the sliding motion of point B and the rotation of its pulley. In the vertical position of the crank A₀A the velocity of the belt is zero: The belt makes a continuous, but intermittent, motion (stepping motion).

The usual application is to drive a transportation belt with intermittent motion, as sometimes required in production machinery. The (infinitesimal) dwell is short, but the motion is very smooth, see the graph below.

Dimensions:

For a given value of the sun gear radius R₀ the other dimensions

are determined as follows:

Planet gear radius AB = R₀/ 2

Crank length A₀A = R₀/ 2

The size of the step of the belt is 2pR₀

The pulleys at C₀ and D₀ may have any radius. In the simulation R₀/ 2 has been

taken, yielding two revolutions for one crank revolution.

Literature: Rankers, H.:

Remarks: see also model 44

<back to collection>