MechDesigner Reference & User Interface > Dialogs

Pulley

Note:

If when you open a model and the Pulley elements do not rebuild, find a Path-Joint in the Assembly-Tree, edit it to open the Pulley dialog, and increase and decrease the Number-of-Teeth.

Use the Pulley dialog to edit the number-of-teeth on a Pulley.

Pulley / Belt Terminology

Term :	Definition
Pulley :	When you do Add Pulley, we add for you the outline of a Pulley, with teeth, to a rotating-Part - see also Types of Pulley The rotating-Part of a Pulley must rotate about the center-Point of an Arc that is on the sketch-path of a Belt.
Belt :	A sketch-path, to represent the path of the Belt, and a Motion-Path FB to control the motion of a Motion-Point along the sketch-path, to represent the motion of the Belt.
We relate the angular motion of each Pulley to the linear motion of the Motion-Point on a Belt by the radius of each Pulley. To control the radius of each Pulley, you can edit the Pulley to control its number-of-teeth and/or edit the Motion-Path FB to control the Tooth-Pitch of the Belt.

Term :

Definition

Pulley :

When you do Add Pulley, we add for you the outline of a Pulley, with teeth, to a rotating-Part - see also Types of Pulley

The rotating-Part of a Pulley must rotate about the center-Point of an Arc that is on the sketch-path of a Belt.

Belt :

A sketch-path, to represent the path of the Belt, and a Motion-Path FB to control the motion of a Motion-Point along the sketch-path, to represent the motion of the Belt.

We relate the angular motion of each Pulley to the linear motion of the Motion-Point on a Belt by the radius of each Pulley.

To control the radius of each Pulley, you can edit the Pulley to control its number-of-teeth and/or edit the Motion-Path FB to control the Tooth-Pitch of the Belt.

Types of Pulley

You can do Add Pulley to a rotating-Part that is kinematically-defined (Type 1) or a rotating-Part that is not kinematically-defined (Type 2).

Type 1: A Driving-Pulley :

Before you do Add Pulley, the rotating-Part is kinematically-defined.

After you do Add Pulley, we control the linear motion of a Belt from the angular motion of the rotating-Part (Driving-Pulley).

Add a maximum of one Driving-Pulley to a Belt.

Type 2: A Driven-Pulley :

Before you do Add Pulley, the rotating-Part is not kinematically-defined.

After you do Add Pulley, we control the angular motion of a rotating-Part (Driven-Pulley) from the linear motion of the Belt.

How to open the Pulley dialog

Double-Click a Pulley

After you add a Pulley, you will need to edit the number-of-teeth - see Add Pulley.

To edit the Pulley:

1.Double-click a Pulley in the graphics-area or Assembly-Tree.

1.See How to Open a dialog

The Pulley dialog is now open.

Pulley dialog - and no Transition-Curve in the sketch-path

Pulley dialog

Pulley Parameters

Number-of-Teeth

The number-of-teeth around the circumference of the Pulley.

The Number-of-Teeth and Tooth-Pitch (see Motion-Path FB) control the P.C.D of the Pulley and the radius of the Arc in the sketch-path.

Pitch-Circle-Diameter (PCD) - read-only

The diameter of the Pitch-Circle, which is co-radial with the neutral line, or pitch axis, of the Belt.

Belt Parameters

Tooth Pitch - read-only ( Edit with the Motion-Path dialog )

The linear distance between two adjacent teeth on the belt.

Belt Length - read-only

The total length of the belt. It is equal to the length of the sketch-loop that wraps around the Pulleys.

The length of the belt will change as you edit the Number-of-Teeth on a Pulley.

You can select a dimension that will control the Belt-Length with the Motion-Path dialog.

Pulley dialog - and Transition-Curve in the sketch-path

Pulley dialog

SPROCKET Parameters

Fillet Radius - the radius that blends with the root of the tooth.

Angular Offset - to rotate the pulley / sprocket so that the Motion-Points engage with the root of the tooth.

Roller Radius - the radius of the Follower-Roller that can engage with the root of the tooth if you want to add a convert the Transition Path to a 2D-Cam.

Sprocket Thickness - the extrusion depth to use when you save the Sprocket as a STEP file.