Safety central shaft extension and contraction control structure of self-opening/closing umbrella

A safety central shaft extension and contraction control structure for use in a self-opening/closing umbrella, the safety control structure comprising a main body, a collar, an operation plate, a pawl plate, and a reversal prevention wheel, the safety control structure being adapted to be received in a handle of the umbrella, the central shaft of the umbrella comprising a first shaft segment having a lower end that receives and fixes a lining tube that forms an opening in a side thereof and is received and fixed inside the main body, the collar receiving therein a spring that is fit over the first shaft segment, the operation plate and the pawl plate being set in engagement with each other and mounted to the main body to be located below one side of the collar, the pawl plate being is biased at one side thereof by a spring, the reversal prevention wheel being mounted to the main body and located below the pawl plate and having one side forming a toothed surface that forms thereon a plurality of ratchet teeth that are inclined in the same direction, the reversal prevention wheel receiving and holding therein a coil spring, a safety rope being wrapped around the reversal prevention wheel and having an end fixed to the reversal prevention wheel and an opposite end attached to a crown of the umbrella, whereby when an operation of compressing the central shaft of the umbrella is in error in closing the umbrella, with the pawl plate and the reversal prevention wheel instantaneously forming engagement therebetween and a pulling action realized by the safety rope, the central shaft that is in the process of being compressed is kept in position thereby preventing abrupt extension of the central shaft caused by the action of an umbrella opening spring of the umbrella.