Wiper arm assembly having locking surfaces

1. A wiper arm assembly, comprising:

a mounting head having a first end with a bottom surface configured for mounting to a vehicle and a pair of laterally spaced sidewalls extending upwardly from the bottom surface to a second end with an axle extending between said sidewalls, said mounting head having a flat locking surface extending along a plane generally perpendicular to said bottom surface;

a wiper arm extending along a longitudinal axis between a first end configured for operable attachment to a wiper blade and a second end having a hub with a pocket extending from an open end for receipt of said axle to a seating surface, said second end of said wiper arm having a protrusion extending outwardly in a direction generally opposite said first end of said wiper arm, said protrusion having a flat locking surface extending along a plane generally perpendicular to said longitudinal axis;

a spring arranged for operable attachment to said mounting head and said wiper arm;

wherein said flat locking surfaces of said mounting head and said wiper arm are configured to be brought into engagement with one another in a shipping position under a force imparted by said spring upon rotating said mounting head relative to said wiper arm from a disassembled position toward said shipping position, said locking surfaces confronting each other in a plane generally perpendicular to said longitudinal axis while in said shipping position and preventing said mounting head and said wiper arm from rotating back toward said disassembled position from said shipping position; and

said mounting head having a spring attachment member extending between said sidewalls with said spring being attached to said spring attachment member, wherein said locking surface of said mounting head extends downwardly from said spring attachment member to said bottom surface.

2. The wiper arm assembly of claim 1 wherein said locking surface of said wiper arm provides a free end of said hub.

3. The wiper arm assembly of claim 1 wherein said axle engages said seating surface of said pocket while in said shipping position.

4. The wiper arm assembly of claim 1 wherein said hub has opposite sidewalls with protrusions extending outwardly therefrom for receipt between said sidewalls of said mounting head.

5. The wiper arm assembly of claim 4 wherein said protrusions are provided as a plurality of elongate ribs.

6. The wiper arm assembly of claim 5 wherein said ribs extends substantially parallel to said longitudinal axis of said wiper arm.