﻿ MechDesigner Reference & User Interface > 2.2 Mechanism-Editor: > Kinematic elements > Add Slide-Joint

## Slide-Joint

 Slide-Joint in MechDesigner Slide-Joint - THK 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. - e.g. R-R-P * Line or CAD-Line.

#### A Slide-Joint in the Graphic-Area

Slide-Joint

The symbol for a Slide-Joint:

 A Narrow Rectangle that is equal to the length of the Line in one of the Parts. A Wide Rectangle that is equal to the length of the Line in the other Part. 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.

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

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

Select two Lines

A New Slide-Joint

STEP 1: Start the Add Slide-Joint command

STEP 2: Click the two(2) Lines

 1.Mechanism-Editor: Click a Line in a 2.Mechanism-Editor: Click a Line 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

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:

 Line in the Base-Part CAD-Line along the center of a Sliding-Part CAD-Line in a Part We want to join the completely-free Part with a Slide-Joint to become collinear with the existing Slide-Joint.

STEP 2:Select two(2) Lines:

 1.Mechanism-Editor: Click the CAD-Line in the Completely Free Part. 2.Mechanism-Editor: Click 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

Two Lines are Compatible

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

 1.Select-Elements: Click the Line at the top of the Element list (CAD-Line2) 2.key down 3.Select-Elements: Click one other Line in the Element list.

You can select:

CAD-Line2 and Line3 are compatible (image above)

OR

You cannot select:

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

Why not Line3 and CAD-Line ?