We will add a Multi-Pulley and Belt system.
We will define the motion of one Pulley and MechDesigner will find the angular motion of other Pulleys.
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
We will add a Line, and then we can add a Rocker in the Mechanism-Editor.
The exact radius of the Arc is not important.
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Select the sketch-loop that represents the path of the belt. The Motion-Point |
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Add one Part near to the centre-Point of each Arc
There is one rotating Part (that is, a Part + Pin-Joint) for each Pulley. The length of each Part is not important. |
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A maximum of one kinematically-defined Part can be a Driving Pulley. |
You must do Add Pulley for each Pulley |
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Add menu > Mechanism sub-menu > Add Pulley - or - Kinematic-elements toolbar > Add Pulley |
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The Add Pulley dialog starts in the Command-Manager. Do Add Pulley to the kinematically-defined Part first. Click, in the graphic-area, from top to bottom.
The Part-Editor opens with sketch-path to which you add the Motion-Path FB
The Part-Editor closes
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MechDesigner adds the Pulley. Do Add Pulley again four more times to add a total of five Pulleys. Notes: Default colours of the Pulleys: Driving Pulleys are Cyan Driven Pulley are Magenta
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Use Edit Pulley dialog box
Edit the Number-of-Teeth on a Pulley.
Double-click a Pulley in the graphic-area - or - |
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In the Pulley dialog-box
Repeat 1 and 2 for each Pulley. |
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When the Driving-Pulley is at 0º, the other Pulleys will also be at 0º. |
Belts have an integer number-of-teeth. Also, belt manufacturers have preferred lengths of belts. We use the Motion-Path dialog-box to enter a Target Path Length The Target Belt Length tool moves a pulley, or another controlling-dimension, to edit the length of the belt. Thus, we need a dimension in the sketch-path that will change the length of the belt. We will edit the length of the Belt to an length that is exactly divisible by Tooth-Pitch to give an integer number of teeth on the Belt. |
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In the design to the left, we will make the Tensioning Pulley the pulley at the top the sketch-path. Therefore, we will use the dimension highlighted in RED. (164.89) This dimension is the Controlling Dimension. MechDesigner adjusts this dimension as we edit the Target Path Length |
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You will see the Actual Path Length = 1228.9mm It is Read-Only.
The Part-Editor opens to edit the Part in which the belt is defined by the sketch-path.
The Part-Editor closes The dimension value shows in the Controlling Dimension box The default Target Path Length = Actual Path Length The Maximum and Minimum Dimension Values are Soft-Limits to the Controlling-Dimension. You can edit the Maximum and Minimum Values if you need to edit the Controlling Dimension by more.
If needed, you can select a different dimension to adjust.
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