Abstract: A vacuum switching valve and a suction system having the same. The vacuum switching valve comprises: a valve body, comprising a first end and a second end, the second end being provided with an air inlet, an air outlet and a through hole; a valve element movably arranged in the valve body; a cylinder, the cylinder being connected to the first end and the valve element, the cylinder drives the valve element to move in the valve body, to close or open the air inlet; a stopper passing through the through hole, the stopper comprising a third end and a fourth end, the third end being connected to the valve element, the fourth end being located on the side of the through hole away from the valve element.

Abstract: A pair of spectacles includes a rim, two angle adjusting devices each mounted on the rim, and two temples each mounted on a respective angle adjusting device. Each of the angle adjusting devices includes a connecting member formed with a locking pawl, and a pivot member pivotally mounted on the connecting member and formed with locking grooves. Thus, the locking pawl of the connecting member is detachably locked in either one of the locking grooves of the pivot member, so that the included angle between the connecting member and the pivot member is changed arbitrarily so as to adjust the angle of the rim relative to the temples.

Abstract: A pair of spectacles includes a rim, two angle adjusting devices each mounted on the rim, and two temples each mounted on a respective angle adjusting device. Each of the angle adjusting devices includes a connecting member formed with a locking pawl, and a pivot member pivotally mounted on the connecting member and formed with locking grooves. Thus, the locking pawl of the connecting member is detachably locked in either one of the locking grooves of the pivot member, so that the included angle between the connecting member and the pivot member is changed arbitrarily so as to adjust the angle of the rim relative to the temples.