Yoga Mat/ Yoga Roller/Camping mat Mat & Floor Series Co., Ltd. , http://www.sdtaekwondo.com In order to avoid the wear or chipping of the cutting edge when the workpiece is cut by the planer, the operator often raises the planer by hand, which is labor intensive. To this end, we have made a simple hinged lifting device, which is described below. The structure of the simple hinged lifting device is shown in the figure. It consists of a roller 1, a pin 2 and 4, a lifting bar 3 and a hinge base 5. The pin 2 and the lifting bar 3 are in an interference fit, and the roller 1 is the same as the pin 2