Pencil Cap or Coupler - New product idea

Those who have school going kids would have experienced this.  Students in the primary school are supposed to write in pencils.   When the pencil length is reduced due to usage, it becomes difficult to hold and write.  Kids are reluctant to use the shortened pencil.  Sometimes even when 1/4th of the pencil length is left, kids don't want to use them.  Not a prestige issue, it is practical issue.

However, parents would not appreciate the idea of throwing away a pencil when 1/4 it is still left!
If a pencil costs Rs.4/-, then its like simply throwing away One Rupee. Isn't it? Even from environment perspective it is not a good idea! Is there any other way to extend the pencil's length and its life?

How about having a pencil coupler/connector (like the one used to connect water pipes/electric pipes)? A simple design is shown in the above picture.  When the pencil is reduced to 1/4th of its size, the coupler can be connected to increase pencil's length, there by making it convenient to hold  and write.  The coupler can also be used as a Cap to protect pencil lead from accidental breaking.!

Any entrepreneur planning to manufacture a new product, can think of this innovative product.  This product can be patented as well.  Currently, there are a few similar products, which are sold in the name of Pencil extender.  However they are very expensive!  The pencil coupler can be made of plastic/PVC material and there by keeping the selling price affordable.

"The history of innovation is the story of ideas that seemed dumb at the time" - Andy Dunn.