The concept was transmitted, but we also added some details.
For " modern" cars, the wiper arms are secured to a round shaped "post" that rotate - being driven from the wiper motor and transmission linkage under the cowl. You pop the black plastic cap on the arm and there is a nut under that secures the arm to the post.
In the 70's, they used a mechanical friction fit for securement of the arm to the post.
The wiper arms are spring loaded to keep the wiper blade on the glass and lock them on the post. To remove the arm you have to relive this spring tension. That is one of the comments above - find a small block of wood to put between the glass and the blade. It will result in the wiper are looking like the shape like a hockey stick.
The other comment from above is to insert something like a drill bit or a nail near the pivot joint of the arm to the "end cap" at the end of the wiper arm (circled in red in the pics) to keep - maintain retain this position, you will see a small hole, this is where you insert the nail - see photos
Now, here comes the fun part. Based on the year of the car, if you look at the end cap - which is more of a "U" shape, there may be a very small tab on the right hand side. With a small jeweler's type screwdriver, you have to move the tab away from the cap, think of the tab moving from 12 to the 1:30 - 2:00 position.
This is a crescent shaped retainer that "Locks" the wiper arm onto the post. This is so when the wiper is working, it will not work its way up the shaft and pop off the post. This was the stype on my 1978 Chrysler. Some years have this lock, some do not. I do not know when Chrysler stated using this lock type of arm. For my 1969 Chrysler, there is no locking tab and that is what is shown in the pictures attached.
The post the arm sits on has a very fine knurled machning- notches that provided a tight friction fit between the post and the arm joint. Once the lock is out of the way, (if you have one) you can work the arm off the post. Be careful as the wiper arm is spring loaded and will want to straighten up - go back to its original potions if the nail or drill bit come out during the removal process.
For the driver side - there is also a secondary arm that connected to a raised dimple on next to the post circled in blue.
There is a neat tool for getting under there and forcing the arm up off the post. I bought one and have used it several time, in my opinion it is worth the money. ; )
A E S Industries 8525 | Pliers Wiper Arm Remover-AD8525