Hi Butler County, it is difficult to tell what is happening with the immature pine cones falling off the trees.  I would speculate that it has to do with the drought we have had this past spring.  A lot of trees will shed the extra leaves of the early spring or the seeds that are on the tree as a result of drought.  The tree has mechanisms in its physiology that causes it to shed some or all of the seeds that have developed in the spring.  Usually the shedding lessens the effect of too many seed pods on the tree that would not get fully developed and be of no use to propagate the tree species.  Again, this has been a strange spring after the sudden drop in temperatures before Christmas last year.  

As you probably have seen in a lot of your landscape plants, the sudden drop in temperatures caused a lot of damage to a lot of different plants.  The loss of buds on the silver maple is also a big possibility.  The loss of the seeds (helicopters) is usually due to a freeze and the loss of the buds on the tree.  Some trees lose the buds due to the high drying winds at the wrong time in the spring.  Also, a combination of all these factors contributed to the loss of seed on the silver maple.  Yea!!!!  Less mess in the rain gutters for once.  Hope this helps.  Don