publication_number US 5697655 A abstract a ball operated automatic vibration safety latching device including a cantilevered arm which is gravity biased to a radial position to leave a catch normally disengaged a ball positioned atop a ball support and a retaining cup attached to the arm and arranged beneath the ball support any undue vibration such as that caused by an earthquake or nearby explosion will dislodge the ball causing the ball to drop into the retaining cup which will cause the cantilevered arm to rotate around its pivot so as to then engage the catch or otherwise block the door a single latching device may be used with two catches to serve two doors or other items that need to be restrained the door is normally completely unimpeded and only requires unlatching in the event that undue vibration has occurred since the door was last closed unlatching the arm allows the door to be opened and automatically resets the device to the normal unlatched mode application_number US 57062495 A description fig1 6 illustrate a preferred embodiment for a latch system according to the present invention the latch mechanism 50 includes a base 2 which is securable to the bottom surface of the cabinet 17 a housing 4 a cantilevered arm 3 pivoting about pivot pin 11 a spherical ball 5 resting atop a ball support 6 and a retaining cup or basket 12 having a centered hole 12a in a bottom portion thereof upon experiencing vibration of sufficient amplitude the latch mechanism 50 actuates to pivot its cantilevered arm 3 into position to grasp the catch hook 1 the catch hook 1 is mounted to the door 16 of the cabinet 17 at a sufficient height to allow.