Fig. 14.
46. Push-Button. Fig. 15 and Fig. 16. By placing [App. 29] in a box, we can make something that looks a little more like a real push-button. Fig. 15 shows a plan with the box-cover removed, and Fig. 16 shows a view of the inside of it, a part of the box being cut away. C, Fig. 15, is a wooden pill-box 1 in. high and 1¾ in. in diameter. Make a ¼ in. hole in the cover of C for the "button," G, which is a short piece of ¼ in. dowel. This rests upon a single thickness of tin, D, which is cut into a strip ⅜ in. wide and about 1¼ in. long. In the bottom of C are two holes just large enough to allow the screws E and F to pass through. The wires, A and B, pass from the binding-posts, X and Y, through small holes burned through the sides of the box, and are fastened under the screw-heads. The whole box is screwed to the wooden base, which is 3 × 4 × ⅞ in., by the screws, E and F. D should have enough spring in it to raise itself and G when the pressure of the finger is removed. The circuit will be closed only when you press the button.
| Fig. 15. | Fig. 16. |
47. Push-Button. Figs. 17, 18, 19. Fig. 17 shows a top view or plan of the apparatus. Fig. 18 is a sectional view; that is, we suppose that the button has been cut into two parts along its length and through the center line. Fig. 19 is an enlarged detail drawing of the underside of the spool, C. The same part is marked by the same letter in all of the figures.