ALEXANDRIA, Va., Dec. 9 -- United States Patent no. 12,491,130, issued on Dec. 9.
"Hollow-structured vibration massager" was invented by Quan Zhao (Guangdong, China).
According to the abstract* released by the U.S. Patent & Trademark Office: "A hollow-structured vibration massager includes a soft rubber sleeve, wherein a hard shell is sleeved inside the soft rubber sleeve; a first motor is fixed inside the hard shell, and a drive end of the first motor is connected to a main crankshaft; an auxiliary crankshaft is fixed outside the main crankshaft, and a plurality of serpentine plates are slidably connected outside the main crankshaft; a soft rubber tube is slidably connected to a top end of the soft rubber sleeve, and a hollow opening is ...