Beach or garden umbrellas incorporating tilting mechanisms have long been known, but invariably have been either difficult to adjust, or, have required complex and failure prone mechanical adjusting mechanisms.
In their simplest form, the respective upper and lower sections of the mast are hinged to each other by a manually adjustable joint including a bolt passing through the two halves of the hinge joint, and a hand-operable clamp nut, whereby the two halves of the hinge joint can be clamped to each other in their required angular relationship. Such mechanisms are difficult to operate, in that the user must hold and position the upper portion of the mast carrying the weight of the umbrella, while operating the clamp nut with the other hand.
Numerous winch operated structures have been proposed for raising and extending the umbrella by means of a pull cord. Mechanisms also have been proposed which will cause tilting of the upper portion of the mast in a stepless manner, if operation of the winch is continued after the umbrella has been fully raised and extended. An example of such a mechanism is described in Militano U.S. Pat. No. 2,721,569, issued Oct. 25, 1955, in which continued operation of the winch after fully raising and opening of the umbrella causes operation of a linkage between the upper and lower portions of the mast, and an adjustment of the tilt of the upper portion of the mast relative to the lower portion. The mechanism proposed is somewhat complex, and includes numerous sliding parts, linkages and pivots, each of which is subject to wear and contamination by dust or sand.