Motography (Jul-Dec 1913)

September 6, 1913 MOTOGRAPHY 179 Recent Patents in Motography By David S. Hulfish PATENT No. 1,038,586. For an Improved FilmFeeding Mechanism. Issued to Albert S. Howell, Chicago, 111., assignor to Bell & Howell Co., of same place. A complete camera mechanism is shown in this 1.038,586 patent, the new feature particularly patented being the film-feeding device. In a camera, the time of open shutter is usually about one-third of the total time used for each picture, whereas in the projector the light is passed through the film for three-quarters, four-fifths or even five-sixths of the total time for each picture. In the design of a projector, the principal feature to be considered is the fast shutter and quick film shift to avoid flicker on the screen. Then steadiness of the picture is obtained by the mechanical perfection in the manufacture of the film shifting parts. In the design of a motion-picture camera, or of a film printer of the stepping type, the 1,038.586 steadiness of the film is the principal feature for consideration, as there is plenty of time for the operation of the film shifting mechanism. In Mr. Howell's improved camera, the pin shift plan of operating is used, but it is applied in a novel manner. Fixed pins are used to hold the film in position during the open period of the shutter, and after each exposure the film is lifted from the fixed pins, into the path of the moving pins. It then is carried forward by the moving pins, and placed again over the fixed Dins in readiness for the next exposure by the shutter. The shift mechanism may be understood from Fig. 1 and Fig. 4 of the patent, reproduced herewith. In Fig. 4, the film gate 29 is shown in side view, (right side, as the cameraman faces the subject to be photographed), the film guide 33 being shown in dotted lines swung out from the body of the film gate. The fixed pins are shown at 36. By the action of the rocker arm 40, pivoted at 41 and connected through parts 44 and 45 to the film guide 33, the film guide is swung forward (to the right in Fig. 4, but to the left in Fig. 1), and the film is lifted from the fixed pins 36, whenever the lower end 42 of the rocker arm 40 is moved as shown dotted. In Fig. 1 may be seen the cam 15 with its routedcam guide 17 for moving the arm 40, and also the mechanism for the moving pins. The moving pins 38 are upon the sliding plate 37, which slides vertically, being driven by the pitman 28 and wrist pin 27 on revolving disk 26. The disk or face plate 26 and the cam 15 are both driven by the wheel 10 and gear 11, turned by the crank, as is also the steady feed mechanism upon the shaft 19. The shutter exposure is made while the pins 38 are passing upward during which time the film guide lies flat against the film gate, upon the fixed pins 36. When the moving pins 38 reach the top of their stroke, the cam 15 operates the arm 40 and moves the film guide forward (to the left in Fig. 1), lifting the film from the fixed pins 36 and to the moving pins 38. The moving joins then start down, dragging the film through the film guide. This is the point at which the illustration of Fig. 1 is taken, the film having just started down. When the moving pins 38 have completed their downward travel, the arm 40 is moved to transfer the film to the fixed pins during the next exposure. Patent No. 1,039,501. For an Improved Motion Picture Camera. Issued to Victor L. Duhem, Oakland, Calif., assignor to American Vinograph Co. The inventor states that his invention applies to the camera or to the projecting machine. The reader however is referred to the discussion of the design of the two types of apparatus as set forth in the review of Mr. Howell's patent No. 1,038,586, above. The design shown in the illustration of the patent is suitable for a camera rather than for a projector, because of the comparatively long period of motion of the film between the successive pictures. The illustration shows the interior of the camera. The large gear numbered 7 drives the four smaller gears, a, b, c, d, and by belt 22 drives also the take-up, 21. Gear b carries the steady-feed sprocket 9, gear d carries the steady-take-up sprocket 10, while gears a and c each carry an eccentric pin 14 and 14 upon which is mounted a loose or "idler" sprocket 15 and 15. The lower pin 14 therefore acts as a beater dog such as is used in the Kinemacolor projector, and at each revolution draws