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. - e.g. R-R-P

* Line or CAD-Line.

The symbol for a 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.

STEP 1: Start the Add Slide-Joint command

STEP 2: Click the two(2) Lines

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-box opens, see Slide-Joint Special Case

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

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

For example:

There are a total three Parts and we would like to join all three Parts to be collinear. We must add two(2) Slide-Joints:

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

Slide-Joint#2 can be between:

Option A: Slide-Joint#2 between Lines 3 & 1 (in Parts 3 & 1)

Option B: Slide-Joint#2 between Lines 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.

Preparation example:

STEP 1:Add Slide-Joint

STEP 2:Select two(2) Lines:

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

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

Therefore, there is ambiguity as to which two(2) Lines you want for the Slide-Joint.

Ambiguity: when MechDesigner is not sure which element to select.

When there is ambiguity as to which elements to select the Select Elements dialog-box opens.

<<< Select-Elements dialog-box

STEP 4: Select the TWO Lines in the Select-Elements dialog

You can select:

•CAD-Line2 and Line3 are compatible (image above)

OR

•CAD-Line2 and CAD-Line are compatible (image left)

You cannot select:

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

Why not Line3 and CAD-Line ?

There is a Slide-Joint between these two(2) CAD-Lines already.

STEP 5: Close the Select-Elements dialog-box

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