 You don't have to have a working model or prototype of your idea in order to get a patent. All that is needed is the ability to describe how your invention is made and used. If you have rough sketches of your concept that would definitely help but it's not necessary. The problem in waiting for a prototype to be developed working on a model is that while you are perfecting your idea somebody else might race to the patent office and file first. This is because in 2013 US underwent the single biggest change in patent law. In this century we moved from a first to invent system which rewarded the first inventor to a first to file system and today it doesn't matter who invented first if they are beaten to the patent office by somebody else who gets their application in first. If you have a new idea it's essential that you race to the patent office and get your filing in because if you focus on your prototype while you're putzing around getting the prototype perfected somebody else may just end up owning the idea preventing you from doing anything with it. So file for the patent first and then you can take your time on perfecting the prototype. You can make changes you can make modifications and you can do all of these things while you're fully protected.