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In This Chapter

16

Calculating Springs

In this tutorial, you calculate a spring for existing

boundary conditions and insert the spring into a drawing.

You copy and edit the spring using the Power Copy and

Power Edit commands in AutoCAD

®

Mechanical 6.

■

Starting the spring calculation

■

Specifying the spring restrictions

■

Calculating and selecting the
spring

■

Inserting the spring

■

Copying the spring with Power
Copy

■

Editing the spring with Power
Edit

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Key Terms

Term

Definition

Belleville spring washer

A washer-type spring that can sustain relatively large loads with small deflections.
The loads and deflections can be increased by stacking the springs.

compression spring

A spring type that can be compressed and can absorb pressure forces.

dynamic dragging

The act of determining the size of a standard part with the cursor while inserting
the part into a side view. The standard part is displayed dynamically on the screen
and can be dragged to the next possible size and length. The values (sizes) are
taken from the Standard parts database.

extension spring

A spring type that can absorb tension forces.

Power Copy

A command that copies a drawing object to another position in the drawing.
Power Copy produces an identical copy of the copied object.

Power Edit

A single edit command for all objects in a drawing.

torsion spring

A spring type that can absorb torque forces.

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Calculating Springs

With the AutoCAD Mechanical Power Pack spring function, you can insert
compression, extension, and torsion springs, as well as Belleville spring washers.
The calculation is carried out in accordance with DIN 2098 or ANSI. The
standard sizes of the springs can be selected from various standard catalogs.

NOTE

The ISO standard parts have to be installed for this tutorial exercise.

In this tutorial, you create a compression spring in two different compression
situations. You calculate and insert the spring in an existing drawing.

First, you open the initial drawing.

To open a drawing

1

Open the file tut_ex14 in the acadm\tutorial folder.

Menu

File ➤ Open

Command

OPEN

2

Zoom in to the area of the spring housings.

Menu

View ➤ Zoom ➤ Window

Command

ZOOM

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3

Respond to the prompts as follows:

Specify first corner:

Specify first corner (1)

Specify opposite corner:

Specify opposite corner (2)

The drawing shows two views (A and B) of the lever and spring housing, to
reflect two different states of compression.

Save your file under a different name or to a different directory to preserve
the original tutorial file.

Starting Spring Calculations

First, you specify the spring and the location.

To specify a spring

1

Start the Compression Spring command.

Menu

Content ➤ Springs ➤ Compression

Command

AMCOMP2D

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2

In the Select Compression Spring dialog, choose Standards ➤ SPEC

®

Catalog A and Front View.

3

Respond to the prompts as follows:

Specify starting point:

Specify the starting point (1)

Specify direction:

Specify endpoint (2)

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Specifying Spring Restrictions

Now, you specify the spring restrictions. The Compression Springs dialog
allows you to restrict the spring selection in various ways.

To specify the spring restrictions

1

In the Compression Springs - Select from Tables [mm] dialog, specify:

Specification:

2 Loads, 2 Lengths

Absolute Set:

Lengths

2

In the Compression Springs - Select from Tables [mm] dialog, choose the Da
button.

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A row for specifying the outer diameter Da is added to the restrictions table.

3

Click into the value field for the diameter Da and choose the now appearing
pick icon.

4

Respond to the prompts as follows:

Specify point for spring diameter:

Select a point on the inner spring housing contour (1)

Now, define the initial spring length.

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5

In the Compression Springs - Select from Tables [mm] dialog, click into the
value field for the length L1 and choose the now appearing pick icon.

6

Respond to the prompts as follows:

Specify point for spring length L1:

Select a point on the spring pressure plate (1)

Use view B of the lever and spring housing to define the compressed spring
length.

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7

In the Compression Springs dialog, click into the value field for the length
L2 and choose the now appearing pick icon.

8

Respond to the prompts as follows:

Specify point for spring length L2:

Select a point on the spring pressure plate in view B (1)

Now, you have defined the geometric boundary conditions, and you can pro-
ceed with the calculation.

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Calculating and Selecting Springs

Now, make the calculation settings and calculate the possible springs.

To calculate and select a spring

1

In the Compression Springs - Select from Tables [mm] dialog, choose the
Additional Calculation Settings button.

2

In the Compression Springs - Additional Calculation [ANSI] dialog, select the
left buckling case, and choose OK.

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3

In the Compression Springs - Select from Tables [mm] dialog, choose Next >.

The possible springs are calculated and the results are displayed in the Com-
pression Springs - Select from Tables [mm] dialog.

4

Choose Select All to select all possible springs for the dynamic dragging
process.

Choose Finish.

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Inserting Springs

Now, you can drag the cursor dynamically to switch between the selected
possible springs. The outline of the spring is displayed in the drawing and the
spring description is displayed in the tooltip.

To insert a spring

1

Select SPEC - 1.6 x 14.1 x 36 and click the left mouse button.

2

Respond to the prompts as follows:

Topical Length (14.28 - 36) [Force/Deflection] <32.01>:

Select a point on the spring pressure plate (1)

3

Continue to respond to the prompts as follows:

Select rod (only closed contours) <Enter=continue>:
Select objects:

Press

ENTER

The spring is inserted as shown below.

Save your file.

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Copying Springs with Power Copy

Now, copy the previously inserted spring from view A to view B, using the
Power Copy command.

To copy a spring

1

Start the Power Copy command

Menu

Modify ➤ Power Commands ➤ Power Copy

Command

AMPOWERCOPY

2

Respond to the prompts as follows:

Select objects:

Select the spring in view A

Specify starting point:

Select point (1) in view B

Specify direction:

Select point (2) in view B

3

Continue responding to the prompts as follows:

Select rod (only closed contours) <Enter=continue>:
Select objects:

Press

ENTER

Insert part reference:

Press

ENTER

The spring is copied into view B. However, you need to adjust the length of
the spring in view B.

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Editing Springs with Power Edit

NOTE

You can also start Power Edit by double-clicking the object you want to

edit - in this case the spring.

To edit a spring

1

Start the Power Edit command.

Menu

Modify ➤ Power Commands ➤ Power Edit

Command

AMPOWEREDIT

2

Respond to the prompt as follows:

Select object:

Select the spring in view B

The Compression Spring - Select from Tables [mm] dialog is displayed.

3

In the Compression Springs - Select from Tables [mm] dialog, choose Finish.

4

Respond to the prompt as follows:

Topical Length (14.28 - 36) [Force/Deflection] <32.01>:

Select the lower contact point of the compressed spring (1)

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5

Continue to respond to the prompts as follows:

Select rod (only closed contours) <Enter=continue>:
Select objects:

Press

ENTER

AutoCAD Mechanical reinserts the spring in its new compressed length into
the housing.

NOTE

If there is a rod in the center of the compression spring, you have to select

the rod so that the representation of the background will be displayed correctly.

The Spring command provides a very useful tool for generating complex
springs in your design. This is the end of this tutorial chapter.

Save your file.

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