Patent 7530591 was granted and assigned to Cequent Performance Products on May, 2009 by the United States Patent and Trademark Office.
A pin box assembly is provided for a trailer. The pin box assembly includes a first section having a trailer attachment point, a second section carrying a king pin and a pivot connecting the first and second sections together. In addition the pin box assembly includes a shock absorber having a first end connected to the first section and a second end connected to the second section. Still further, the pin box assembly includes an air spring connected between the first and second sections.