Add Slide-Joint

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Add Slide-Joint


Slide-Joint in MechDesigner

Slide-Joint in MechDesigner

Slide-Joint - THK

Slide-Joint - THK

Slide-Joint in SOLIDWORKS

Slide-Joint in SOLIDWORKS


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.

A Slide-Joint in the Graphic-Area



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 - 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


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


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

STEP 2: Click the two(2) Lines

1.Mechanism-Editor: Click a LineRed-14-1b in a free-Part

2.Mechanism-Editor: 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-box 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.

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:

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 Completely-Free PartRed-14-3

We want to join the completely-free PartRed-14-3 with a Slide-Joint to become collinear with the existing Slide-Joint.


STEP 1:Add Slide-Joint


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


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 LinesRed-14-5


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


Two Lines are Compatible

Two Lines are Compatible

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

1.Select-Elements: Click the LineRed-14-4 at the top of the Element list (CAD-Line2)

2.MD-Ctrlbkey down

3.Select-Elements: Click one other Line in the Element list.

You can select:

CAD-Line2 and Line3 are compatible (image above)


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.

Two Lines are Compatible

Two Lines are Compatible

Two Lines are NOT Compatible

Two Lines are NOT Compatible


STEP 5: Close the Select-Elements dialog-box

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

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