Read this Stuff it would be interesting for us ; atleast i think 
http://www.patentstorm.us/patents/5676634-description.html
or
http://www.freepatentsonline.com/5695445.html

http://www.patentstorm.us/patents/5676634-description.html
or
http://www.freepatentsonline.com/5695445.html