The working principle of an automatic umbrella depends on a spring with tension. When the user presses the button, the umbrella will open automatically due to the release of spring pressure.
If an automatic umbrella retracting device is designed, opposing forces will be used on the same axis, which will inevitably form opposing forces. In mechanics, the resultant force of two opposite and equal forces is zero, that is, the umbrella can neither be opened nor retracted.
If we add a device to open and close the umbrella automatically, it will greatly increase the cost of the umbrella and make it big and bulky. No manufacturer wants to do it, and no one will buy it.
Extended data
An umbrella that can be opened and closed by pressing the button on the handle.
Automatic umbrella capable of automatically opening and closing an umbrella: a compression spring sleeve is arranged outside the compression spring used for opening the umbrella, and the compression spring sleeve is sleeved in the skeleton connecting sleeve, and the skeleton connecting sleeve is provided with radial clips, and the two ends are wedge-shaped and can slide left and right. A spring bolt is arranged on the outer side of the skeleton connecting sleeve, a sliding multi-threaded spiral inner jacket is arranged above the umbrella handle, and a matching multi-threaded thread is arranged between the two. When the umbrella is folded, the sliding outer sleeve and the inner sleeve can rotate to press the umbrella tightly.
The spring umbrella retracting device can be an umbrella retracting compression spring between the umbrella top frame connector and the umbrella opening frame connector. When the umbrella-opening compression spring is pressed, the umbrella-opening compression spring can be opened and compressed, the spring bolt is pulled down, the clip slides out, the umbrella-opening compression spring closes the umbrella, and the sliding spiral sleeve is rotated to compress the umbrella-opening compression spring and prepare to open the umbrella.
References:
Baidu encyclopedia-automatic umbrella