The rod passes through the cover 10, in the upper part of which there is a thread. A spring 13, fixed by its upper end in the slot of the upper end of the rod 18, in which there is a finger 16, which protrudes on both sides of the rod and articulated lever 15 with a forking lever 11, is screwed on this thread.
The brass pin (pencil), drawing the diagram, is plunged into the left end of the lever 11, and the right end of the lever is 11 hingedly connected by thrust 14 to motionless ears 17 in the lid 10. In addition, the thrust of 15 is hingely connected using 12 rods with two racks 9 installed on the cover 10, which is attached to the indicator case with a nut 19. A bracket is attached to the cover of 10, at the end of which a screw 27 with a handle is screwed, at an point blank 8 (rack). Cover 10 with the entire writing mechanism can rotate around the vertical axis. This is necessary so that you can let the lever 11 with a pencil to paper fixed on the drum 6, and take it away from it. Screwing or unscrewing screw 27, you can adjust the pencil pressure on paper.
Holder 7 drum 6 sits on the axis 4. Spring 5 at one end is fixed on the axis 4, and the other on the holder 7 of the drum. Drum 6 is put on the holder and tightened with a nut. The paper on which the diagram is drawn is pressed to the drum with a plate paper holder (two plates). In the lower part of the holder there is a groove in which a cord wound on the holder is placed. One end of the cord is fixed in the slot available in the holder, and the second end is connected to the indicator drive. The rotation of the drum in one direction occurs under the action of the cord, and in the other – under the influence of spring 5.
To maintain and direction the cord is the video 1, which rotates on the axis passing through the roller holder 26. The roller holder is fixed with a nut on the bracket 2, which, in turn, is pressed with a nut 3 to the lower plane of the site 24. Axis 4 drilled inside. From below it is probably 25 with a technical petroleum jelly or tavot.