Page:Photographic Shutter (Low & Shakespeare).pdf/3

 move in the same direction) will oscillate the double lever F in the opposite direction, and thus close the shutters. By this means during one lateral movement of the lever-plate E, as indicated by dotted lines in Fig. 3, the double lever F has been oscillated in both directions, and the shutters or slides open and close during said single movement of the lever-plate E, and they will remain in their closed position, while the piston-rod of the engine returns to its normal position, as in Fig. 1, as soon as the air-pressure is released, bringing the lever-plate E back to the proper position for a new operation. By means of a pivoted stop H the movement of the lever-plate E is arrested at the time the shutters are thrown open, and in this case of course the shutters are closed by the return-stroke of the engine. From this it will also be seen that the lever-plate E may be dispensed with, provided the operative power is applied to the oscillating double lever F to merely open and close the shutters or slides.

Returning to Fig. 1, While it is designed that the dog D (after being tripped by the engagement of its inclined end x with the projection n) shall fall by its own weight to a proper position to again form an engagement of its shoulder 3 with the projection n of the lever-plate E, ready for the next operation, if desirable, a spring o may be employed to bring said dog back to place after being tripped, as shown in Fig. l, or otherwise; but said spring is not deemed necessary by us.

Having thus described our invention, what we claim as new, and desire to secure by Letters Patent of the United States, is&mdash;

1. In a photographic shutter, the combination of the two slides, a centrally-pivoted double lever attached to and adapted to open the slides during its oscillation in one direction and to close them during its oscillation in the opposite direction, a pivoted lever-plate connected with and adapted during its movement in one direction to impart both of the oscillating movements to the double lever, and means for operating the lever-plate, substantially as set forth.

2. In a photographic shutter, the combination of the centrally-pivoted double lever having the end projections and the projections each side of its pivot, the pivoted lever-plate, the pivoted dog connecting with a projection of said lever-plate and with the projection which is on the double lever, said lever-plate being also provided with an extension adapted to engage one of the side projections of said double lever during the lateral swing of the lever-plate, and the slides or shutters forming a cam engagement with the end projections of the double lever, substantially as set forth.

3. In a photographic shutter, the combination of the slides, the double lever for operating them, the pivoted lever-plate, the pivoted dog joined to the double lever and having a shoulder in position to be engaged by a projection of the lever-plate, and a projection on the case adapted to trip the dog and disengage said projection, substantailly as set forth.

4. In a photographic shutter, the combination of the slides, the lever-plate having the pin to engage the dog, the pivoted double lever having the pin for engaging with the lever-plate, said lever-plate provided with the extension for engaging the pin of said double lever, and the pivoted dog forming a connecting-link between the double lever and lever-plate and adapted to trip, as stated, substantially as set forth.

In testimony of the foregoing we have here =unto subscribed our names in presence of witnesses.


 * GARRETT W. LOW.
 * WILLIAM SHAKESPEARE,.

Witnesses as to first name:

Witnesses as to second name:
 * , Jr.,