polycarbonate or glass turning now to fig5 u2013 7 embodiments of the door hinge assemblies are shown in a first embodiment an upper hinge assembly 30 includes a rigid member 21 such as a threaded rod fig6 or a metal strip fig5 having a first end pivotally attached to the door 20 and a second opposite end pivotally attached to the vehicle 10 via bracket 331 each of the pivot points can be formed using any suitable means such as a pin 23 arrangement as shown fig7 illustrates one embodiment for mounting the upper hinge assembly to the cart 10 the rigid member 21 and optional assist 335 are pivotally mounted to bracket 331 u2032 as shown bracket 331 u2032 is shaped to be received by receiving bracket 332 that is mounted to the cart 10 when bracket 331 u2032 is properly positioned in receiving bracket 332 holes in each align allowing insertion of a bolt pin or preferably a spring loaded quick release pin 280 to removably secure the assembly to the cart fig7 a illustrates another embodiment of an upper hinge assembly in this embodiment the positioning of an l shaped mounting bracket is located inside the vehicle as shown in order to maintain clearance as the door swings from a closed position to an open position the rigid member 21 is bent in the vicinity near the doorway preferably at an angle of about 25 u00b0 so that.