Getting Started Tutorials - MechDesigner > Tutorial 17: Belts and Pulleys > Step 17.2: Option 1 - Fixed Pulley Centers > 1 Driving-Pulley, multiple Driven-Pulleys

Fixed-Center Pulleys

We will add a Multi-Pulley and Belt system.

We can define the motion of ZERO or ONE Pulley. In this model we will define the motion of ONE Pulley. THe motion of the others are found from the velocity of the Belt.

We will edit the Number of Teeth on each Pulley

We will edit the Length of the Belt with Controlling Dimension, using the Target Belt Length parameter.

Preparation

STEP 1: Add a closed sketch-path (sketch-loop) to represent the Path of the Belt

1.Edit the Base-Part

2.Part-Editor: Add a sketch-path with more than two Arcs

3.Part-Editor: Add a dimension to each Arc. The exact radius of the Arc is not important.

The Belt will be Driven by a Driving-Pulley, which will be a Rocker.

4.Part-Editor: Add a Line - its start-Point is merged or coincident with the center-point of an Arc.

5.Close the Part-Editor

STEP 2: Add Motion-Path FB

1.Click Kinematic FB toolbar > Add Motion-Path FB

The Command-Manager has one selection-box

2.Select the sketch-path that represents the belt.

3.Click to close the Command-Manager

The Motion-Point is at the start-Point of the sketch-element you select in the sketch-path.

STEP 3: Add a Rotating-Part for each Pulley.

1.Add one Part for each Pulley

2.Add one Pin-Joint to join the start-Point of the Part to the center-Point of an Arc

The length of each Part is not important.

We will add a Motion-Dimension FB to one of the rotating-Parts. It will be the Driving-Pulley.

STEP 4: Add a Motion-Dimension FB to the Part you wish to be the Driving-Pulley.

1.Click Kinematic FB toolbar > Add Motion-Dimension FB

a)Click the Pin-Joint at the start-Point of the Line in the sketch

b)Click the Line

c)Click the CAD-Line along the Part to be the Driving-Pulley

A Belt has a maximum of one Driving-Pulley.

All Pulleys at other Arcs along the Belt are Driven-Pulleys.

Do Add Pulley

GST-GA-CM-AddPulley-Multiple-05

STEP 1: Start the Add Pulley command

1.Machine elements toolbar > Add Pulley

Add Pulley starts the Command-Manager.

STEP 2: Select the elements

Do Add Pulley to the rotating-Part that is kinematically-defined (the Rocker)

1.Click the Pin-Joint

2.Click the Motion-Path FB

The Part-Editor opens with sketch-path to which you add the Motion-Path FB

3.Click the radius Dimension of the Arc

The Part-Editor closes

4.Click the Part joined with a Pin-Joint at the center of the Arc.

Click in the Command-Manager.

The Driving-Pulley is now in the model.

GST-17-1-MultiP-E

STEP 3: Add four more Pulleys

1.Do STEP 1 and STEP 2 four times (4x)

A total of five Pulleys are in the model.

There is one Driving-Pulley and four Driven-Pulleys.

Notes: Colors of the Pulleys in the image. (see Edit menu/toolbar > Application-Settings > Graphics tab > Display Colors)

Driving-Pulleys are Lilac

Driven-Pulley are Magenta

Use Edit Pulley dialog

GST-17-1-MultiP-F

Edit the Number-of-Teeth on a Pulley.

Open the Pulley dialog

1.Double-click a Pulley in the graphic-area

See How to open a dialog

In the Pulley dialog ...

GST-DIALOG-PULLEY

2.Edit the Number-of-Teeth

Repeat 1 and 2 for each Pulley - a total of five Pulleys.

GST-17-1-MultiP-G

Open the Motion-Dimension dialog

1.Edit the Motion-Dimension FB to open the Motion-Dimension dialog.

2.Enter 0º as the Base-Value parameter

3.Close the Motion-Dimension dialog

When the Driving-Pulley is at 0º, the other Pulleys are also at 0º.