Before organizing a group ideation session or grilling your friends and family for solutions to your critical sub functions, you should mine your own brain for solutions. The methods described below will allow you to get the most out of your brain.

Method 1: brain dump

While you have been talking to potential customers for your product, you have undoubtedly thought of potential solutions to their problem. Therefore the 1st thing you want to is to document the solutions to the critical functions embedded in the concepts or ideas you have already thought of. This is commonly referred to as a brain dump.
Method 2: search for products that perform similar functions

One way to find products that perform similar functions is to visit a large home repair center like Home Depot or Lowe’s store. In the aisles of the stores are thousands of products and gadgets that do almost any function imaginable. If you look in the power tools section you will find gold mine of interesting ideas. I recommend touring the store with your cell phone and taking pictures of the products that you find.

Another method to find products for similar functions is to ask people who have experience with lots of mechanical products. These keep people could be years who work on cars, colleagues from work, machinists you know and oldest guy at the neighborhood hardware store. You can bet that he is heard requests for all kinds of tools and gadgets. Buying him a donut might be the best investment you can make.

 

 Method 3: mechanism websites
Here are a few websites you might consult to learn how things work and how you might apply them to your product.

Mechanism animation here.
More mechanisms and cams here.
How stuff works here.

Mechanisms with cams animated here.

Method 4: Browsing part catalogs

Sometimes you can find solutions for critical functions by searching catalogs from parts suppliers. Below are links websites of companies that supply a wide variety of products, parts and mechanisms. Each website also has a search function. Spend some time getting to know each website.

McMaster Carr’s website can be accessed here.
Stock Drive Product’s website can be accessed here.
J. W. Winco’s corporate website can be accessed here.
Reid supplies corporate website can be accessed here.

Amazon’s industrial, Business and Scientific supplies can be accessed here.

Method 5:¡Biomimicry – The practice of developing technologies inspired by nature. (biologically inspired engineering)

Those who are inspired by a model other than Nature, a mistress above all masters, are laboring in vain. – Leonardo Da Vinci

How does nature solve the problem you are facing?

Resources:

15 examples of successful biomimicry can be found here.

Another interesting website promoting biomimicry can be found here.