Last week, we tried several variations of a spring-loaded ball cannon, just about all of which lacked enough push to send the balls into the central vortex. The one pictured uses a spring-powered plunger made from copper pipe mounted in a 4″ pvc drain pipe with end cap. It is very hard to pull the plunger back and then it sends the ball about a foot into the air. We were able to send the ball flying by striking the plunger with a hammer, but had no idea how to make that happen on the robot.
During the week while substituting for the Ag teacher at Stanberry, Mr. Nelson got a bit of inspiration from a ball-tossing machine that was sitting in the classroom. (The Ag teacher is also the softball coach.) This machine uses an over-center spring to cause an aluminum arm to smack a softball a few feet into the air for batting and fielding practice. This video shows the machine in operation without a ball:
This week, Nathan brought in a sketch of ideas that he worked on. His sketch shows a hammer-struck lever to throw the ball into the air:
Some combination of these ideas shows promise. By having an over-center spring driving the hammer, a servo or motor could trigger a ball shot like this crude model demonstrates:
There are also an increasing number of interesting ideas on this subject available on YouTube. Check out this one.