<< Click to Display Table of Contents >> Navigation: MechDesigner Reference & User Interface > 2.2 Mechanism-Editor: > Kinematic elements > Mechanism | Add Pin-Joint |
See also: Edit-Pin-Joint ( Motor and Gearbox Sizing )
Technical Definition: Revolute Joint : |
A joint that only allows relative rotary motion between two Parts (rigid bodies) on one Mechanism-Plane. |
MechDesigner definition : Pin-Joint : |
A joint between two Parts on a Mechanism-Plane that forces a Point in one Part to be coincident with a Point in the other Part. |
Point : |
A fixed position on the XY-Plane of a Part. |
Point (alternative definition) |
A Point represents an Axis that is perpendicular to the Part Mechanism-Plane. |
Pin-Joint (alternative definition) : |
A joint in which an axis (defined by a Point) in a Part is made to be a coincident with an axis (defined by a Point) in a different Part. The axes are perpendicular to the Mechanism-Plane. |
The XY-Plane of all Parts (and the Base-Part) in a Mechanism-Editor are coplanar with the Mechanism-Plane. |
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<<< Pin-Joint <<< Pin-Joint |
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STEP 1: Add Pin-Joint
STEP 2: Select two(2) Points:
The two(2) Points become coincident at the Pin-Joint. If the Select-Elements dialog opens - see Special-Case |
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See also: |
Add Pin-Joint (Simple Case)
Frequently, a design has more than one Pin-Joint at the same position, which join together more than two Parts. The rules to add coincident Pin-Joints, explained below, become important when you need to also add Motion-Dimension FBs to specify the motions of one or two(2) of the Parts at the Pin-Joint. Example: We want to join Points(1,2,3) that are in Parts(1,2,3) with Pin-Joints(1,2) at one position. Pin-Joint#1 is between Points 1 & 2 (in Parts 1 & 2) Then, Pin-Joint#2 has two(2) options: Option A: Pin-Joint#2 is between Points 3 & 1 (in Parts 3 & 1) - or - Option B: Pin-Joint#2 is between Points 3 & 2 (in Parts 3 & 2) When to do Option A or Option B becomes important when you need to also add Motion-Dimension FBs to specify the motions of the two(2) Parts. |
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Preparation example:
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STEP 1:Add Pin-Joint #2
We have clicked a total of three(3) Points. •One Point at •Two Points at However, the Pin-Joint is between two(2) Points. Therefore, there is ambiguity as to which two(2) Points you want for the Pin-Joint. Ambiguity: when MechDesigner is not sure which element to select. |
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Select-Elements dialog-box
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STEP 2:Select the Points in the Select-Elements dialog-box:
Which two Points do we select from the three Points? There are three ways to select two(2) elements from three elements •You can select Point11 and Point5 |
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- or - •You can select Point11 and Point7. |
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However, you cannot select Point5 and Point7. Why? Because Point5 and Point7 are joined with a Pin-Joint, already. Note: the word 'not' the image to the left, at the bottom of the dialog |
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STEP 2:To confirm again, select the Points:
The Select-Elements dialog-box closes. The Points move together to add the Pin-Joint. |
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Top-Tip:
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Add Pin-Joint - Special Case