| 摘要 |
This invention relates to umbrellas in general. In particular it relates to umbrellas which automatically open and close. This automatic opening and closing of the umbrella in the presented embodiments is accomplished by means of the rotation of a threaded rod. The improvements disclosed herein relate to improved means for more economically controlling the source of motive power used to open and close the umbrella. A key improvement disclosed herein includes a means for conserving the power of the batteries used to power the motor which causes the threaded rod to open and close the umbrella embodiments utilizing this means of opening and closing. An additional improvement disclosed is the use of a multiple-lead threaded rod which avoids the binding and "cross-threading" of previous designs. Also disclosed is a means for conveniently converting the umbrella to the ordinary manually opened and closed umbrella should the necessity occur. Two different mechanisms are also disclosed whereby such electrically powered umbrellas can be collapsed to a shorter length. In one such mechanism the length is alternately lengthened and shortened manually. In another mechanical arrangement invented, the electric motor which opens and closes the umbrella ribs also simultaneously lengthens and shortens the umbrella shaft.
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