Novel ruler and compasses assembly

The invention discloses a novel ruler and compasses assembly. The novel ruler and compasses assembly comprises a centering pin device, a variable-radius device, a protractor device, a pen clamping device and an idler wheel device. The pen clamping device is arranged on a rotary leg of the variable-radius device. The centering pin device and the idler wheel device are both installed on a center leg of the variable-radius device. The centering pin device is located between idler wheels of the idler wheel device. One end of the protractor device is fixed to the rotary leg of the variable-radius device, and the other end of the protractor device is hinged to the center leg of the variable-radius device. By the adoption of the novel ruler and compasses assembly, circles with different diameters and any lines can be drawn, the angle measurement function is achieved, three purposes are achieved through one ruler, and the trouble of searching for tools during drawing is saved. According to the novel ruler and compasses assembly, limitation to a specific pen is avoided, all required pens can be placed in a pen container to be used through a locking piece, and then required lines and circles can be drawn. Meanwhile, the novel ruler and compasses assembly can also serve as a protractor to be used for angle measurement, using is convenient, implementation is easy, and the novel ruler and compasses assembly can be used easily and rapidly.