PROBLEM:

 An oscillating follower is to pause at the beginning for 90 degrees of cam rotation, then move through 40 degrees CW for 90 degrees of cam rotation.  Another pause for 90 degrees of cam rotation is followed by the follower moving 40 degrees CCW in the last 90 degrees of cam rotation.

Timing Chart:

          The timing chart for the motion above will look like this:  NOTE: CCW is considered positive; therefore, the initial motion is negative.

KINEMATICS:

1.No kinematic profile has been specified here, so we are free to select the best for this movement.  See Kinematic Profile Properties. You can also watch the video on Kinematic Basics.

2.Lets look at the Modified Sine.  Notice that the displacement, velocity, and acceleration are all zero at the beginning and end of this profile.

3.Now look at the Modified Trapezoid.  This has the same beginning and end as the Mod Sine. 

4.Here we are going to use the Modified Sine in the CW segment and Modified Trapezoid in the CCW segment, and then we will compare the two.

Now open Cam Designer SE and click on the Kinematics button or hit Atl K to open the Kinematics Input form.

1.Select the Cam Type as Circular (default), and then select then Oscil button in Follower Type.  See

2.At this point, make sure the Kinematic Starting Angle has 0.0000 deg in the edit box above the Follower Information.  See Kinematics.

3.From the Profile dropdown arrow, select Dwell, enter 90 in the Segment Amount and hit ENTER, Click the New at the bottom of the Cam Information section, or hold the Alt key down and press N.

4.Now select Modified Sine from the Profile dropdown list, enter 90 in the Segment Amount box, Tab, or hit the ENTER key and put in 1 in the Segment Incr. box.  Enter 40 for the Follower Displacement and the direction as CW and finally 0 for the Final Velocity.          

5.Now click the Seg Data+Graph radio button in the Output section and the Kinematic Form will look like this:

5.Complete the kinematics by entering a Dwell of 90 degrees for the next segment and for the last, select Modified Trapezoid for the profile and 90 degrees for the Segment Amount.

6.Select CCW for the direction and click the Arrow beside the Follower Displacement box   until 40 shows.  Enter 0 for the Final Velocity and the the form will appears as below:

8.If the graph does not appear as seen above, it may not have been set up.  For the Graph Setup see the video.  Also you may want to view the video for the Axis Setup. 

9.This completes the kinematics.  Notice in the Cam List the cam is unnamed as well as the Kin.  We must save the kinematics to give the cam and the Kin a name.  Click on the button and select Save As, browse to the folder you want to save the Kin file in and give it a name.  When this is done, both the Cam and the Kin will have that name as seen below:

GEOMETRY:

1.For the geometry, the problem statement does not specify any dimensions.  To enter the geometry and load information, Click the Geometry Button in the Main window, or select Geometry from the menu, or Alt G.

2.Select SI as the Default Units, Glb for the Cam Type and from the Followers dropdown select Oscillating-roller, then click the Rib radio Button and the form will appear as below:

3.Enter the data as seen below then click one of the output buttons , or select one of the output selections  and the form will appears as below:

4.Click on the Cam Drawing Button and the Drawing will look like this:

NOTE: The increments are 1 degree in the Kinematics so the computation for the cam curves will be at 1 degree increments.  If after approval of the design, you want to compute the curves at say 0.25 degree increments there is a way of doing that without changing the increments in the Kinematics Form.

5.Return to the Cam Shaft form and click on File|Preferences.  Then click the Geometry Preferences and enter 0.25 in the Quick Increment edit box as below:

6.Now return to the Geometry Form and click the Quick Compute button , then Click the Cam Drawing button again. NOTE: if the drawing did not change click the New button  to redraw and the drawing will appears as below:

For a video of this tutorial see Globoidal Oscillator.