Make the Motion-Part a Slider and not a Rocker

In this Tutorial:

Video 1:

1.We delete a Pin-Joint (the middle of the two Joints in the R-R-P dyad), and add a new Pin-Joint
2.We change the Dyad Closure of the R-R-R Dyad

Video 2:

3.Move the Motion-Dimension FB to the Slide-Joint. The input becomes a Slider.

Typically, the name of the new mechanism is a Slider-Crank.

4.We will look at the Kinematics Tree again.



tog_minusVideo 1: Move Pin-Joint and Change Dyad Closure

Delete Pin-Joint

Add Pin-Joint

Change Dyad Closure

tog_minusVideo 2: Change from Crank-Slider to Slider-Crank


Motion-Dimension Rocker


Motion-Dimension ... a Slide-Joint ... make a Slider


Step by Step...

tog_minusEdit the Pin-Joint on the Sliding-Part.

We want to move the Pin-Joint to the different end of the sliding-Part.

We delete the Pin-Joint, and add a new Pin-Joint.

There are many ways to delete an element.

In this step we will practice using the contextual-menu with 'Hover-above-element + Right-Click' , and then click Delete Element


STEP 1: Delete the Pin-Joint with the Sliding-Part

We can delete an element with a contextual menu - IF we can right-click the element and only that element.

You may need to edit your Symbol Selection Size. I reduced mine to be one less than the Symbol Size.

See Edit menu > Application-Settings > Accessibility tab > Graphics > Symbol Selection Size

The image shows ONLY the Pin-Joint is Red



1.Hover + Right-Click'  above ONLY the Pin-Joint

If more than one element becomes red, a different contextual-menu will show.

2.Click Delete element at the top of the contextual-menu (the menu may not be easy to see!)


STEP 1: Move the Sliding-Part and add a new Pin-Joint
1.Hover + Drag the Part Outline of the Sliding-Part.

When the start-Point of the sliding-Part is near to the end-Point of the other Part.

2.Click Kinematic elements toolbar > Add Pin-Joint
3.Click the two PointsRed-14-1bRed-14-2.


STEP 3: Edit the Closure - again.

If the R-R-P Dyad Closure is the same as this image to the left, then we can change its closure.

There is a right-click short-cut...


1.Click Kinematic elements toolbar > Change Closure

The short-cut to complete the command:

2.Right-Click a Part in the R-R-P Dyad.

The right-click short-cut selects the element and also closes the Command-Manager.

Do step 1 - 2 again and again until the Dyad is the same as the image.

Note: You can do the right-click short-cut when the Command-Manager has one selection-box or only one more element to select for the selection-box.

btn_delkeywordMove the Motion-Dimension FB from the Pin-Joint to the Slide-Joint

When the Motion-Dimension FB is at a Pin-Joint, we call the Motion-Part a Rocker.

When the Motion-Dimension FB is at a Slide-Joint, we call the Motion-Part as Slider.


Before we can add a new Motion-Dimension FB to the Slide-Joint we must delete the Motion-Dimension FB at the Pin-Joint


STEP 1: Delete the Motion-Dimension FB
1.Click the Motion-Dimension FB, or the Motion-Dimension arrowhead, in the graphic-area


The Motion-Dimension FB element will be in the Selection-Window

2.Right-click the Motion-Dimension FB in the Selection-Window

In the contextual menu

3.Click Delete in the contextual-menu


Alternatively, you can click an element so that it becomes red, then use your delete key on your keyboard.


All of the Part-Outlines in the kinematic-chain should be Blue.

The kinematic-chain has one degree-of-freedom again.

Remember: Blue Part-Outlines are NOT kinematically-defined.


2.Drag the rotating Part

Drag the Part-Outline of the Part that was the 'Rocker'.

Move the Parts to a position that is similar to that shown in the image to the left.

NOTE: Some users can make a Part-Outline Red by hovering over the Part-Outline at the arcs, near the start-Point of the Part

Now, we will add a new Motion-Dimension FB.


STEP 2: Add the Motion-Dimension to the Sliding Part.
1.Click Kinematic FB toolbar > Add Motion-Dimension FB


When we want to add a Motion-Dimension FB to a Sliding PartJoint

The Command-Manager shows you must select three elements from the graphic-area.

Notes on the Command-Manager

Do not click inside a selection-box.

If you do click in a selection-box, you clear all elements.

Each time you select an element, the Command-Manager automatically advances to the next selection-box.


Select the three elements for Add Motion-Dimension FB

1.Click First Element: the Slide-JointRed-14-1b symbol

The Slide-Joint symbol is two rectangles that are along the length of each Line that specify the Slide-Joint.

Please look at the image carefully to see the symbol of the Slide-Joint.



When the Slide-Joint is the first element, the second and third elements you must select are Points.

2.Click Second Element: Click a PointRed-14-2 at one end of the Line in the Base-Part

I find it best to select the Point that is the start-Point of the Line.



The second Point is at one end of the Line in the Free-Part. A Free-Part has a Blue Part-Outline.

3.Click Third Element: Click a Point at one end of the Line in Added-Part

Again, I find it best to select the Point that is the start-Point of the Line.


4.Click OK-tiny-11-15 in the Command-Manager to complete the command.


You can also Right-click in the graphic-area to complete the command.

The kinematic-chain is now kinematically-defined again. The Part-Outlines are Green.

The Part that was a Free-Part is now a kinematically-defined Part.

Because the Part is a child to a Slide-Joint, it is a Slider.


STEP 3: Add a Motion FB - if needed.
1.Click Kinematic-FB toolbar > Add Motion FB
2.Click the graphic-area.
3.Connect a wire from the output-connector of the Linear-Motion FB to the new Motion FB
4.Connect a wire from the output-connector of the Motion FB to the Motion-Dimension FB




If the Closure is not correct

STEP 4: Change the Dyad Closure if it is not correct.
1.Do Kinematic element toolbar > Change Dyad Closure
2.Click OK-tiny-13-17 in the Command-Manager


btn_delkeywordThe Motion-Dimension and Slide-Joint in the graphic area


Slide-Joint BEFORE we add a Motion-Dimension FB

A Free-PartRed-14-4 joined to a Solved-Part

The symbols that represent a Slide-Joint are:

Red-14-1b Wide Rectangular Box: along the Line of one Part.

Red-14-2 Narrow Rectangular Box: along the Line of the other Part.

Red-14-3 Small Arrowhead: at the start of one Line

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


Slide-Joint AFTER we add a Motion-Dimension FB

The Free-Part is now a Solved-PartRed-14-4 and has a Green Part-Outline. This means the Part is now kinematically-defined.

The small arrowhead, and the Wide and Narrow rectangles are Green.

The symbols for the Motion-Dimension include:

Red-14-1b The Motion-Dimension

Red-14-2 The Dimension Line and the Extension Lines

Red-14-3 The Motion-Dimension FB

Increasing motion-values move the Slider in positive direction, as indicated by the small arrowhead.

The Kinematics Tree

The Kinematics-Tree has changed in Tutorial 2.

It has changed from a:

Rocker and R-R-R Dyad (Step 2.1)

to a:

Rocker and R-R-P Dyad (Step 2.3)

to a:

Slider and R-R-R Dyad (This Step)


This Kinematic-Chain is a Slider and an RRR Dyad.

The Slider is a Motion-Part.

It has three elements:

c.Mot-Dim Slider – a Motion-Dimension FB for a Slider

The RRR Dyad is one of the five Planar Dyads.

The RRR Dyad has five elements:


Tutorials and Reference Help Files for MechDesigner and MotionDesigner 14.2 + © Machine, Cam, Mechanism, and Motion Design Software by PSMotion Ltd