# How to Make a Simple 3-D Ball Kicking Leg Mechanism Using CATIA

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In this instructable, I'll show you a step-by-step guide on how to construct, and maybe simulate, a 3-D product of a kicking human's leg with a Quick-Return Crank.

P.S. You may build the mechanism by yourself from any material you want i.e. wood. You may also put simple gears and a motor to drive your mechanism.

If you're a beginner in using CATIA, it may take some time, but not that long, to get used to the program.

Also, with this instructable, you can make a Ball Shooting Arm, in a way.

Requirements:
- CATIA Application
- knowledge in CATIA [for newbies, I'll be making a step to show you the buttons/elements that you will be using]
-(optional) pen and paper for doodling

REMINDER: Only a 3-D a software product.

Good Luck!

Here's the simulation of the finished product:

### Teacher Notes

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## Step 1: [For Beginners] Knowing the Tools You'll Use

*When the Construction/Standard Element is selected, your line will be a dashed line which can be a guide in your drawing and it will not be seen when you exit workbench.

*When you exit workbench, white points means sketch is closed, black points means sketch is open

Hint: To change the units, Tools > Options > Parameters and Measurement > Units > Length > Millimeter (mm)

When sketching, green lines = the sketch is closed and can be padded, etc., violet lines = OVER CONSTRAINED

Note: Deselect Snap to Point at Sketch Tools

You can freely explore the whole CATIA environment. :)

## Step 2: Dimensions of Your Kicking Leg

Measure the leg you would be sketching.

In my case since I'm only 5'7", the dimensions of the picture above is my lower body's measurement. Hahaha

*You can change the dimensions.

## Step 3: Creating Your 2D Drawing

To create a new part, you can either press Start > Mechanical Design > Part Design or Ctrl+N then select Part.

Select on the yz plane then press Sketch.

## Step 4: Creating the Upper Leg Structure

Begin by creating the upper leg, which was given as 420mm

Click the Constraint button and then click on the line, a dimension will be shown. Double-click on it and then enter the desired Value.

## Step 5: Setting the Min. and Max. Angles of the Upper Leg

Create another line to determine the initial and final position of your upper leg

The extreme angles are 0deg and 60deg with reference to the Vertical Line.

To create the angle dimension, click Constraint then click on the two lines then set the value.

## Step 6: Creating the Quick-Return System

1. Create a construction(dashed) line 200mm from the upper leg point. It will be used to drive
the arm through the quick return mechanism.

2. Connect the two points together. Make sure they are coincidental.

3. 15deg is the angle between the two lines created. You can choose your centre point as long as the two lines are in 15deg with each other.

4. When a centre point has been chosen, make a circle with a radius equal to the length of the long line. The centre point of the circle is the point you chose.

5. Make a constraint between the point of the smaller line to the circle.

6. The resulting value, 160.105mm  will be the diameter of the crank. The centre point of the crank must be fixed. Right Click on the point > Point.** object > Fix

7. Click Quick Trim then select the longer line inside the crank (circle with D160.105) (second picture)

8. Make a line replacing that trimmed line. Make sure they are properly constrained. (coincidence)

9. Constrain the longer line.

## Step 7: Creating the Rest of the Kicking Leg

*The 300mm line should be the 400mm lower leg but I used it just like the 200mm on the thigh part. It will be used to drive the lower leg.

To make the rest of the kicking leg, we will be doing the Three-Bar Synthesis (KINEMATICS).

1. Draw another thigh(420mm) 30deg from the vertical thigh.

2. Create the lines of the lower leg. Make sure they all have the same lengths.

3. The first 300mm line should be horizontal since it is the initial position of a leg when kicking.

4. The second 300mm line (30deg from the Vertical) depends on you. In my case, it's 130deg.

5. The third line should be 160deg to avoid any malfunction.

6. Connect the endpoints of the 300mm lines. (2nd Picture)

7. Make a perpendicular line at the midpoint of the two lines.
Constrain the point and the line > Right Click > Perpendicular

8. Click the two endpoints of the two lines > Constraint > Right Click > Coincidence

9. Make a circle whose centre point is at the intersection of the two lines. (To be used as a guide)

## Step 8: Finalizing the 2-D Design

1. Make a line from the point of intersection before to the endpoint of the 300mm line.

2. Constraint it.

3. Delete the unnecessary lines just like in the picture. (1st picture)

4. Make a line parallel to the 300mm line. Set the value to 100mm so that it will complete the length of the lower leg. (2nd picture)

5. Create the foot. In this case, the foot is 85deg with reference to the lower leg.

## Step 9: Fixed Points

Make sure to fix the points that needed to be fixed. See picture.

## Step 10: Testing Your 2-D Drawing

To test your drawing, you can turn the smaller line which is the crank. See Picture.

How does it look?

## Step 11: Here Comes the 3-D Modelling! the Foot First

Hint: Look at 5th Picture.

A. Foot (See 1st Picture)
*Click on yz plane > Sketch
(Use the lines, circles, constraint, etc.)

1. Make a vertical construction line(VCL) and then make another construction line(CL) 5 deg to the right of the VCL

2. Draw draw a D60mm circle at the top endpoint and a D40mm circle at the bottom endpoint of the angled CL.

3. Draw another circle on top of the D60 circle with a 80mm diameter.

4. Draw a line in tangency and coincidence with the D80 and D40 circle. Make sure to trim too much lines. Just like in the first picture left sidt.

5. Quick trim the unnecessary lines to reach the right side. Make sure to be consistent with your dimensions.
The smaller circle is for the "screw."

6. Exit Workbench > Pad > 100mm > OK

7. Click on the upper surface of your foot (See 2nd Picture) > Sketch

9. Copy the 3rd Picture sketch which consists of two rectangles.
Each rectangle has its side in coincidence with the line of the sides of the foot.

Hint: You can click the line on the foot even though it's from another sketch to constraint it

10. Exit Workbench > Pocket (below Pad) > Type: Up to Last > OK

## Step 12: Thigh and Lower Leg

Note: MAKE SURE TO TRIM LINES!
*To have the Horizontal and Vertical Measure Directions, when you constraint two centre points, Right Click then Choose.

B. Thigh Part

1. Copy the First Picture just like the foot part

2. Exit workbench > Pad > 100mm > OK

3. Click the ZX Plane > Sketch

4. Copy the Second Picture

5. Exit workbench > Pocket > Type: Up to last > More > Type: Up to last > OK

6. Make a plane
*To make a plane, click on the Plane(3rd Picture) > click the YZ Plane > Offset: 25mm > OK

7. Sketch on the new plane

8. Copy the 4th picture. ( C = Coincidence, T = Tangecy)

9. Exit workbench > Pocket > Depth: 50mm > OK

10. Save CATPART

C. LOWER LEG
*Create a new CATIA PART.

*Sketch on the YZ Plane

1. Copy the 5th picture.

2. Exit workbench > Pad> Depth: 100mm > OK

3. Click on the shin part of your lower leg. (6th picture)

4. Copy the 7th picture.

5. Exit workbench > Pocket > Type: Up to last > OK

6. Click on the back part > SKETCH

7. Copy the 8th picture. Make first a CL in tangency with the bottom part of the big circle at the left

8. Exit workbench > Pad> Depth: 60mm > OK

## Step 13: Stand

*To have the Horizontal and Vertical Measure Directions, when you constraint two centre points, Right Click then Choose.

1. Sketch: XZ Plane > Copy First Picture > Pad > First Limit: Length: 550 mm > Second Limit: Length: 600mm > OK

2. Sketch on the front part of your stand

3. Pad > 60mm > OK

4. Repeat  #2

5. Copy Third Picture

6. Pad > 40mm > OK

## Step 14: Thigh Holder (I Can't Think of a Better Name. HAHA!)

1. Make a circle with a diameter = 180mm

2. Pad > 20mm > OK

3. Sketch on the front part of your "PLATE" (the one you made on step 1 and 2)

4. Make a circle with a diameter = 100mm
*Make sure that the circles are CONCENTRIC

5. Pad > 100mm > OK

6. Sketch on the back part of your PLATE

7. Copy the first picture (Again, make sure that the circles are CONCENTRIC)

8. Pad > 20mm > OK

## Step 15: The Rest of the Parts

For the screws, make 4 parts:

[D = Diameter, P = Pad]

1. D = 100, P = 100
2. D = 60  , P = 100
3. D = 30  , P = 120
4. D = 30  , P = 40

For the other parts:
Copy what's on the pictures

*The distance between the circles are the lengths on the 2-D drawing

Note: They are different parts. Don't put them all together!

## Step 16: PUTTING THEM ALL TOGETHER! One by One

Start > Mechanical Design > Assembly Design
A new window will open with name Product1.

Click Existing Component(EC) > choose your stand, the fixed part on the thigh.

Click Fix Component then click your stand.

Click Coincidence Constraint(CC) > Copy the first picture > Copy the second picture

CC > Copy Third Picture > Copy Fourth Picture > OPPOSITE > OK

UPDATE. (Ctrl + U)

## Step 17: The Other Parts.

Do that to other parts like the thigh, lower leg, and the foot together with the "screws", the cranks, and the reference part.

Make sure to rely on the 2-D Drawing.

I'll post photos to guide you.

If you have questions feel free to comment! :)

If you have done it, then Congratulations! :D

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## 2 Discussions

Can you post a link to the software you used please? Thanks