Add Slide-Joint

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Add Slide-Joint

Slide-Joint

Slide-Joint in MechDesigner

Slide-Joint in MechDesigner

Slide-Joint - THK

Slide-Joint - THK

Slide-Joint in SOLIDWORKS

Slide-Joint in SOLIDWORKS

Terminology

Slide-Joint :

A Slide-Joint forces a Line* in a Part to be collinear with a Line* in a different Part.

A Slide-Joint removes two degrees-of-freedom from the model.

A Slide-Joint allows only rectilinear translation motion between two parts (rigid bodies).

Prismatic Joint :

The kinematic and equivalent term for a Slide-Joint.

Kinematics-Tree :

Joints in a Dyad use the letter P to represent a Slide-Joint. - for example: R-R-P dyad

* Line or CAD-Line.

Derived Names:

sliding-Part :

a Part that you join with a Slide-Joint to a different Part.

A Slide-Joint in the Graphic-Area

Slide-Joint

Slide-Joint

The symbol for a Slide-Joint:

Red-14-1b A Narrow Rectangle that is equal to the length of the Line in one of the Parts.

Red-14-2 A Wide Rectangle that is equal to the length of the Line in the other Part.

Red-14-3 An Arrowhead that is the Positive-Direction* of the Slide-Joint.

* The Positive-Direction is important if you want to add a motion to the Slide-Joint.

See Positive direction of Slide-Joints and Motion-Dimension.

IMPORTANT: To calculate reaction Forces on a Slide-Joint:

The length and position of the Lines should be equivalent to the actual design.

Add Slide-Joint:

Select two Lines

Select two Lines

A New Slide-Joint

A New Slide-Joint

STEP 1: Start the Add Slide-Joint command

MD-Icon-AddSlideJoint

Add menu > Mechanism sub-menu > Add Slide-Joint

OR

Kinematic elements toolbar > Add Slide-Joint

STEP 2: Click the two(2) Lines

1.Click a LineRed-14-1b in a free-Part

2.Click a LineRed-14-2 in a different Part

The two(2) Lines become collinear to add the Slide-Joint.

The Positive Direction of the Slide-Joint is identified by the small arrowhead.


If the Select-Elements dialog opens, see Slide-Joint Special Case

 

VIDEO: Add Slide-Joint - Simple-Case

Video: Add Slide-Joint - Special-Case


Special Case: two(2) or more collinear Slide-Joints

Frequently, a machine design has two(2) collinear Slide-Joints between three Parts.

You must decide which two(2) Lines from which of two(2) Parts you want to select for each Slide-Joint.

For example:

There are a total three Parts. You must add two(2) Slide-Joints:

Slide-Joint#1 - joins Lines 1 & 2 (in Parts 1 & 2),

Slide-Joint#2: joins

Option A: Lines 3 & 1 (in Parts 3 & 1)

or

Option B: Lines 3 & 2 (in Parts 3 & 2)

Option A or Option B is important when you also add a Motion-Dimension FBs to control the motions of the two(2) Parts.


MD-GA-SlideJoint-Prep-Special-0

Preparation example:

Red-14-1b Line in the Base-Part

Red-14-2 CAD-Line along the center of a Sliding-Part

Red-14-3 CAD-Line in a Part that is Completely-FreeRed-14-3

You want to join the Part that is completely-freeRed-14-3 to be become collinear with the existing Slide-Joint.

MD-GA-AddSlideJoint-SC2

STEP 1:Add Slide-Joint

MD-Icon-AddSlideJoint

1.Mechanism-Editor: Add menu > Mechanism menu  > Add Slide-Joint

OR

1.Mechanism-Editor: Kinematic elements toolbar > Add Slide-Joint

STEP 2:Select two(2) Lines:

1.Mechanism-Editor: Click the CAD-LineRed-14-4 in the Completely Free Part.

2.Mechanism-Editor: Click Lines Red-14-1bRed-14-2 at Red-14-5

MD-GA-AddSlideJoint-SC2A

You have clicked a total of three(3) Lines.

However, the Slide-Joint is between two(2) Lines.

Therefore, there is ambiguity. Which two(2) Lines do you want for the Slide-Joint?


Ambiguity: when MechDesigner does not know which elements you want to select.


MD-Dialog-Select-Elements-SlideJoint

When there is ambiguity, the Select Elements dialog opens.

<<< Select-Elements dialog


 

Two Lines are Compatible

Two Lines are Compatible

STEP 3:Select the TWO Lines in the Select-Elements dialog

1.Click a Line (CAD-Line2) at the top of the Element list (CAD-Line2)

2.MD-Ctrlbkey down

AND

3.Click one other Line in the Element list.

You can select:

CAD-Line2 and CAD-Line are compatible

OR

CAD-Line2 and CAD-Line3 are compatible


You cannot select:

CAD-Line and CAD-Line3 are NOT compatible (image below)

 

Why not CAD-Line and CAD-Line3 ?

There is a Slide-Joint between CAD-Line and CAD-Line3 already.

 

 

 

 

Two Lines are Compatible

Two Lines are Compatible

Two Lines are NOT Compatible

Two Lines are NOT Compatible

MD-GA-AddSlideJoint-SC3

STEP 5: Close the Select-Elements dialog

Select-elements: Click MD-OK-tiny-11-15 to close the Select-Elements dialog.

There are now two(2) Slide-Joint between three(3) Lines