Untitled record

Application filed January 14, 1889t Serial No. 296j300. (No model,)

To all whom it may concern:

_ Be it known that I, Robert E. M. Bain, a citizen of the United States, residing at the city of St. Louis, State of Missouri, have in- yc’ited acertain new and usefid Improvement in Shutters for Photographic Cameras, of which the following is a full, clear, and exact description.

My invention relates to improved means io of operating the shutters of photographic cameras, and is an improvement on my invention, for which I have obtained Letters Patent, dated September 27,1887, No. 370,673, for improvement in shutters for photographic 15 cameras.

My invention has for its object to vary the speed of the shutters when opening and closing the camera-tube for instantaneous exposure.

As described in my said patent, the shutters swing past each other on their respective pivots within a case surrounding the camera-tube, each shutter having a circular opening which coincides with that of the 25 camera-tube when the shutters are at halfstroke. Each shutter is formed with a curved slot, through which passes the pivot-pin of the other shutter, and with a short straight slot. Through the last-named slots of the shutters and through vertical slots formed through the front and back of the casing passes a pin which is connected with the pneumatic motor, the whole operating so that on the full vertical movement of the pin in either direction the shutters are opened and closed to the camera-tube.

Now my present invention consists in two (or more) springs having alterable tension or force and applied separately or collectively 40 to the actuating-pin of the shutters, whereby the speed of the latter· when opening and closing the camera-tube for instantaneous exposure may be varied at pleasure, combined with a spring-catch for holding and releasing 45 the shutters.

On the accompanying drawings, Figure 1 represents a front elevation of a camera-tube and shutter-case with the shutters closed according to my invention; Fig. 2, a left-hand 50 end view thereof, omitting the catches seen at the lower part of Fig. 1; Fig. 3, a rear elevation; and Fig. 4, a similar view to Fig. 3, with the camera-tube open for time-exposure, like letters of reference denoting like parts in all the figures. 55

Referring to Fig. 1, a a' represent the shutters, having, respectively, the circular openings I) b', pivots c c', curved slots d d', and straight slots e e', all arranged, as shown by dotted lines, witliin the casing/, surround- 60 ing the camera-tube g, and operated, substantially as described in my said patent, by the pin i, which passes through the combined slots e e' of the shutters a a', and through the vertical slots h in the front and back of the 65 casing / the pin i in the present instance being fixed in a slide / which is mounted between guides / on the front of the casing f.

Bearing upward against the pin i, and normally closing the shutters a a' to the camera- 70 tube g, is the arm k of a spring k k', which passes spirally round a fulcrum-stud Z, fixed to the casing/; and thence by an arm k' to a bar m, which is fixed to the casing/and formed on its upper edge with a series of notches 1 2 3 75 4 5, (more or less,) in notch 1 of which the arm k' of the spring k k’ is, shown locked.

Adjacent to, but shown out of contact with, the actuating-pin i is Hie arm n of a second spring n n', which is of greater tension than 80 the spring k k', and provided with fulcrum 0 and notched bar 71, similar in all respects to the spring k k'. By this arrangement, (the pin i being previously pulled down against the pressure of the spring k k' by any suit- 85 able means in the operation of the shutters a a',) on releasing the pin i, the shutters a a¹will be opened and closed in instantaneous succession by the upward pressure of the spring k k' on the pin i, and at a speed cor- 90 responding to the tension imparted to the spring k k' when its arm k' is locked in notch 1 of the bar m.

By successive!j^r shifting the arm k' to the notches 2 3 4 5 of the bar m the tension of 95 the spring k k' and speed of the shutters a a’ will be correspondingly increased; or the arm k of the spring k k' may be thrown out of contact with the actuating-pin i and the arm n of the spring n n' engaged therewith, so 100 that by shifting the arm n' to notches 2 3 4 5 of the bar p further variations in the speed

404,375 of the shutters» a' are obtained, owing to the difference of strength between the springs k k' and n n'; or, again, the arms k and n of the springs k k' and n n' may be engaged 5 collectively with the pin i, and the arms k’ n' alternately or simultaneously shifted along the notches of their respective bars m p, for producing still further variations in the speed of the shutters a a', this feature being of imio portant advantage in taking instantaneous negatives.

q represents a lever-catch pivoted to the back of the casing /, and formed with a hooked end q', having a bevel-shaped back, which is 15 normally held across the path of the actuating-pin i by a spring /, connecting the lever q with the casing/, combined with a stop-pin / on the casing, so that the pin i, when pulled downward along the slot h for making an in20 stantaneous negative, forces back the catch q until clear of the hook q', when the latter is returned by the spring q² and holds the pin i in the closed position of the shutters a a', as seen in Fig. 3. For releasing the hook q' 25 from the pin i, the lever q is thrown over on its pivot by hand or other suitable means.

In making a time-exposure I use a stoplever r, pivoted to the casing/and formed at its end adjacent to the actuating-pin i with 30 a tooth or catch r', which, on the lever r being thrown over to a certain extent on its pivot, crosses the slot h and forms a stop to the pin i, as seen in Fig. 4, when the shutters a a' are at half-stroke or the camera-tube g fully open. . . 35

The movement of the lever r on its pivot may be controlled by the stop-pin c, which projects through a slot r* in the lever r, or by any other suitable provision therefor.