The blue arrows show the beige engine gasflow. The doors (sky colored) will open to direct the gasflow from backwards to forwards to slow the aircraft. The doors will close when not in use.
The purpose of this video is to explain the mechanism that controls the movement of the doors.
The pink cylinder moves the green slider which rotates the yellow rocker by a sine mechanism (yellow rocker, green and red slider). The door is the connecting rod of a four-bar linkage consisting of the yellow and orange rocker.
This video was made based on
https://upload.wikimedia.org/wikipedia/commons/transcoded/3/32/JT15D_Thrust_Reverser
STEP files of this video:
https://www.mediafire.com/file/7hdd3daqkn4bk74/BucketThrustReversalSTEP.zip/file
Inventor files of this video:
https://www.mediafire.com/file/1yy1swwg1e4nf5o/BucketThrustReversalInv.zip/file