In sole plates known heretofore that involve the use of wheel trucks mounted on a shaft and supported for tilting movement by a strut or tongue projecting into a socket made integral with the sole plate, the shaft has been threaded into a boss, and both the boss and the socket have been formed at an angle to the sole plate. This is illustrated in U.S. Pat. No. 4,058,323, and in a somewhat different form, in U.S. Pat. No. 4,159,830.
One of the objects of this invention is to provide a sole plate adapted to use with a wheel truck mounted on a shaft and supported for tilting movement by a tongue projecting into a socket made integral with the sole plate, that can be produced in a simple two-piece mold.
Another object is to provide such a sole plate that can be made economically of plastic but which is strong.
Other objects will become apparent to those skilled in the art in the light of the following description and accompanying drawing.
USPTO Backgrounds
USPTO Backgrounds