US2394614A - Double exposure prevention device - Google Patents

Description

Feb. 12, 1946. M. R. HUTCHISON, JR 2,394,614 I DOUBLE EXPOSURE PREVENTION DEVICE Filed NOV. 16, 1944 FIG].

FIG. 23% FIG. 8.

36 45 32 26 3 20 FIG 9. MILLER R.HUTCHISON, JR.

" A INVENTOR L W BY 75 L 136 Z ATTORNEYS Patented Feb. 12, 1946 UNITED STATES PATENT orncs DOUBLE EXPOSURE PREVENTION DEVICE Miller R. Hutchison, Jr., Rochester, N. Y., assignor to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey Application November 16, 1944, Serial No. 563,700

12 Claims.

This invention relates to photography and more particularly to a means for preventing double exposures upon film carried by a roll holding camera. One object of my invention is to provide a simple form of mechanism which consists of few and inexpensive parts and which may be readily assembled by relatively unskilled help. Another object of my invention is to provide a mechanism connecting a, shutter trigger and a film winding key post by which the trigger will be locked against a second actuation until film has been Wound. Other objects will appear from the following pecification, the novel features being particularly pointed out in the claims at the end thereof.

In my copending application for Double exposure prevention camera, Serial No. 535,511, filed May 13, 1944, now Patent 2,367,504, granted January 16, 1945, I have disclosed a double exposure prevention device in which there is a pair of scissor-like arm for accomplishing the desired locking of the trigger until a fresh film is wound into place. My present invention is for an improvement over the device shown in my copending application. I have somewhat simplified the structure shown therein and have produced a double exposure prevention device which can be successfully operated in an extremely restricted area. Certain other improvements will appear from the following specification. 4

Coming now to the drawing wherein like reference characters denote like parts throughout:

Fig. 1 is a top plan view of a camera including a double exposure prevention device constructed in accordance with and embodying a preferred form of my invention. In this figure a cover plate has been removed from the top of the camera;

Fig. 2 is a section taken on line 2-2 of Fig. 1 with the parts arranged in a trigger latching position;

Fig. 3 is a fragmentary view simila to Fig. 1 but with the parts in a position in which the trigger is unlatched and is ready for operation;

Fig. 4 is a fragmentary sectional view taken on line 4-4 of Fig. 3;

Fig. 5 is a view similar to Fig. 3 but with the parts in a trigger latching position;

Fig. 6 is a view similar to Fig. 4 but with the trigger depressed into a shutter-operating position;

Fig. '7 is an enlarged fragmentary sectional view taken on line |--'l of Fig. 2;

Fig. 8 is an enlarged fragmentary detail showing a portion of one of th slidable members; and

Fig. 9 is a view similar to Fig. 8 but showing another embodiment of my invention.

In the present invention 1 have provided a shutter trigger locking mechanism in which the locking members consist of two simple slide members which may be bent up from rod stock and which include a portion which may slide axially of the rod members and arms extending from the ends of the slidable member for engaging the film winding mechanism and th shutter trigger.

More specifically, the camera I shown in Fig. 1 may be of any standard type which includes a top wall 2 rabbeted around the edge 3 so a to receive a cover plate 4 which may have a downwardly extending flange 5 adapted to fit on the rabbet 3. This provides a shallow, box-like chamber 6 of very little greater width than the normal width of a camera in which the double exposure prevention mechanism may be entirely enclosed. The cover plate 6 may be held in place as by screws 1.

The camera I may be of the usual type having a supply film chamber 8 and a take-up film chamber 9 adapted to receive a supply film spool and a take-up film spool H. As is customary of cameras of this type, the film is wound from the spool 10 to the spool I 1 past an exposure aperture. In order to wind the film the take-up spool chamber 9 is provided with a key post 13 which may have the usual key or flange I4 for engaging the winding slot in the take-up spool H. In addition, this key post is provided with a cam I5, this cam being keyed to the shaft 13 and turning with it.

The camera may also be provided with a trigger member I6 having a head I! terminating in a shoulder 18 from which a shaft IQ of somewhat smaller diameter extends downwardly through the wall 2 of the camera and into a po sition in which it may operate any known type of camera shutter.

A collar 20 is mounted to slide about the shaft l9 and is normally spring-pressed upwardly by a spring 2| engaging the underside 22 of the collar 20 at one end and supported by a metal housing 23 at the other end. The flange 22 on the collar prevents this fiange from being moved upwardly beyond the position shown in Fig. 2 but permits the sleeve 20 to move downwardly when it is engaged by the shoulder I8 on the trig er as illustrated in Fig. 6. The position of the shoulder l8 relative to the camera wall 2 is such that, unless this shoulder can be depressed below the wall 2 as shown in Fig. 6, the shutter cannot be operated.

In order to prevent the trigger from being moved downwardly to its Fig. 6 position until film has been wound, I provide mechanism connecting the key post i3 and the trigger l6 and this mechanism preferably consists of two rods 25 and 26. These rods can conveni ntly be made of square wire, although any other suitable material may be used for these two slidable members. I prefer to provide turned-over arms 2! and 28 on the ends of the slide members 25 and 26, these arms being of suihcient length to engage the cam I5. A spring 29 fastened between the arms 2'! and 28 always tends to move these arms into contact with the cam [5.

At the opposite ends of the arms 25 and 23 I provide arms 3| and 32 which are adapted to engage the shutter trigger |5 and/or the sleeve 23.

In order to guide the rods and 26 for their sliding movement I prefer to provide two supporting members 34 and 35. Member 34 is provided with apertures 36 which are of such a size that the rod 25 may twist or turn in these bearings. Support is provided with apertures 31 which also permits sliding of the rods '25 and '26. Because of the confined space between the cover 4 and camera wall 2 the chamber 6 does o D8 mit the ends 2'1 and 28 to turn without striking the cover 4. Therefore, turning movement of the ends 3| and/or 32, permitted by forming 45, tends to distort the rods 25 and 26 from a normal position to which they will tend to return.

It will be evident that, since the ends of the rods 21 and 28 adjacent the winding key post H! are held against turning any material distance and since the opposite ends of these rods may be turned, the end of the rods 3| and 32 may move up or down a short distance. The normal shape of the rods is such that the ends 3| and 3?. will both have a position of rest in which they may lie fiat against the camera wall 2, as best shown in Figs. 3 and 4. However, when these ends 3| and 32 are engaged between the shoulder ll! of the trigger and the sleeve 29 they may be moved upwardly as indicated in Figs. 2 and '7, and when this movement takes place a twist or torsional movement is given to the rods 25 and 26, thus effecting a light spring pressure on the rods tending to turn them to their normal position of rest flat against the wall 2 as shown in Fig. 3.

With the apparatus as thus far described it will be obvious that when the parts are in the Figs. 3 and 4 positions the trigger |6 may be depressed to make an exposure. As the shoulder 58 is lowered it engages the sleeve 22 and moves the sleeve against the pressure of spring 2| as the rod l3 moves downwardly to actuate the camera shutter. During this movement the triggel" button slides down while the rod ends 3| and 32 engage the sleeve 20 and finally these ends 3| and 32 snap over the upper edge of the sleeve as shown in Fig. 6. As soon as the trigger is released the spring 2| will cause the trigger i! to move upwardly and the sleeve moves upwardly under the impulse of spring 2|. However, since the two arms 3| and 32 rest against the outside of the push button when the shoulder 18 passes between these arms, the arms may snap between the shoulder |8 and the top wall 40 of the sleeve 22. One rod has reached this position in both Figs. 2 and 7. If the operator should forget and again depress the trigger IS the rod between the shoulder |8 and the wall 40 of the sleeve 22 would serve as a latch element and would prevent the trigger from being moved downwardly a suifioient distance to make an exposure. The operator would be, therefore, automatically notified that film has not been wound. By turning the winding key 4| (shown in Fig. 2) the key post I3 is turned and with it the cam l5. This cam is so arranged that it will strike first one arm 21 and then the second arm 28, thereby moving first arm 3| and, second, arm 32 away from a locking position with respect to the trigger. It is always necessary to turn the Winding key 4| more than to wind an exposure length of film into place.

Assuming that the trigger locked with only the arm 32 in latching position as shown in Fig. 2, when the operator turns the winding key 4| so that the arm 32 is moved away from the trigger the arm will immediately snap down into its Fig. 3 position. This is caused by the tension or distortion placed in the rod when it is moved upwardly by the spring 2| after the preceding exposure.

It is, of course, possible that both arm 3| and 32 will simultaneously lie in the same latching position. If so, one after the other will be released by Winding film in the above-described manner.

Another-embodiment of my invention is shown in Fig. 9 in which the rod I26 is shown with an end |32 so mounted that it may distort rod I26 by raising it rather than by twisting as in Fig. 8. This requires a chamber 6 somewhat deeper so a bearing I36 will permit such flexing, this bearing being generally rectangular as shown.

One of the advantages of the devices described above is that they will operate regardless of the position in which the winding key handle 4| is left after an area of film has been wound into place. Thi is true because a complete locking of the trigger can take place when only one arm is in a latching position. Consequently, if the film should be wound leaving the cam I5 .in the Fig. 3 position, this arm would prevent the arm 32 from latching the trigger but, in any event, the arm 3| would be left in a position in which it could do the latchin alone. On the other hand, if the film winding ceases with the cam in the Fig. 5 position, both arms 3| and 22 may be in a latching relationship to the trigger |6 since the spring 29 will draw both these arms toward the trigger.

With the preferred form of slide members 25 and 26 made of non-round wire, such as square wire, it is a very simple matter to hold one end of the arm against turning so that when the arm 3| or 32 moves upwardly with the trigger as shown in Fig. 7, it will at the same time put a light twist or tension in the rod so that, as soon as the arm 3| or 32 is released from its latching position by winding the film, the arm will snap downwardly into the position shown in Fig. 4 about the outside of the sleeve 22 which will hold the arms out of locking engagement with the trigger until the trig er is depressed to a shutter actuating extent as indicated in Fig. 6.

It is usually only necessary to move an arm 3| or 32 a comparatively small extent, as for instance the 10 which I have indicated diagrammatically in Fig. 8. It is of course desirable to have these arms work with extremely light tension because, otherwise, a correspondingly heavier spring 2| would be required to normally hold the sleeve in its uppermost position. It is of course obvious that the slide members could be made of other materials, but wire having one or more fiat sides is desirable because it makes the latch more positive in its trigger and sleeve engagement. Round wire flattened at the latch end may be used.

It will be noticed that in the present embodiment of my invention the trigger latching members do not require a pivotal mount as in the first embodiment of my invention and that they are of such a construction that, if desired, the camera wall 2 can be made of suitable molded materials so that the supports for the rods 25 and 26 can be not only made extremely inexpensively but they can be.so made that the cost of assembly is comparatively small. Moreover, while I have shown the cover plate 4 to enclose a relatively small area 6, this area is somewhat exaggerated in the drawing and the construction can actually be made so that the camera is only a very little wider than a camera omitting the double exposure prevention feature; This is at least partially accomplished by providing a forming 45 around the shutter trigger 46 which isof sufliclent depth to permit the rotative movement of the arm 32 about the rod 26 to accomplish the locking result above outlined.

While I have described a second preferred embodiment of my invention, it is obvious that the parts can be made slidable as above described utilizing other shapes and forms, and I contemplate as within the scope of my invention all such forms as may come within the appended claims.

I claim:

1. A double exposure prevention device for cameras comprising, in combination, a camera, a film winding key post carried thereby, a cam on the key post, a shutter trigger, a collar slidably mounted on and encircling the trigger and movable to and from a raised position of rest, a

spring nonmally holding the collar in one position, a pair of resilient slidable members each having an arm at both ends, the arms at one end engaging the cam on the film winding key post and the arms on the other end positioned to engage the trigger and collar, a slideway carried by a camera wall for each slidable member including means for guiding said slidable members for longitudinal movement, means for preventing rotational movement of portions of each slidable member spaced from the trigger, whereby said trigger and sleeve engaging arms may be held in a normal position of rest against the camera wall, said arms being movable from the normal position of rest and being flexed by engaging and moving with the trigger and collar as the trigger is released after an exposure and the collar moves to its position of rest, said winding key post moving said trigger and sleeve engaging ends from the trigger and sleeve through movement of the cam whereby the flexed arms may snap back to their normal position of rest against the camera wall and the trigger may be again depressed.

2. A double exposure prevention device for cameras comprising, in combination, a camera, a film winding key post carried thereby, a cam on the key post, a shutter trigger, a collar slidably mounted on and encircling the trigger and movable to and from a normal elevated position, a spring normally holding the collar in one position, a, pair of resilient slidable members each having an arm at both ends, the arms at one end engaging the cam on the film winding key postand the arms on the other end positioned to engage the trigger and collar, a slideway for each slidable member for guiding it longitudinally and means for preventing a flexing movement of that portion of the slidable member spaced from the trigger, whereby said trigger and collar engaging arms may be held in a normal position engaging the outside of the collar in its normal position, said arms being movable from the normal position and being flexed by engaging and moving with the trigger and collar as the trigger is released after an exposure, said slideway including a second support for each slidable member positioned adjacent the trigger and sleeve in which the slidable members may both turn and slide for definitely positioning the slidable members with respect to the winding key post, said winding key post moving said trigger and collar engaging ends from the trigger and collar through movement of the cam whereby the flexed arms may snap back to their normal position and the trigger may be again depressed.

3. The combination called for in claim 1 in which the slidable members are formed of a nonround rod having a straight portion from which the arms for engaging the key post and winding key cam are bent at right angles to the straight portion of the rod.

4. In a double exposure prevention device for cameras having walls, a film winding key post, and a shutter trigger, the combination with said winding key post, of a cam carried thereby, a collar slidably mounted on the trigger, mechanism for operatively connecting the winding key P st and trigger comprising a pair of slidable rods each rod including offset arms, one for engaging the key post cam and the other for engaging the trigger and the collar slidably mounted thereon, said trigger including a shoulder, a, spring normally pressing the collar towards the shoulder on the trigger, a spring means for moving the offset arms towards the cam at one end and the trigger and collar at the other end, whereby either or both slidable rod arms may engage the trigger beneath the shoulder and may engage the collar adjacent thereto forming a latch preventing effective movement of the trigger for operating the shutter, and whereby a turning movement of the cam in winding film may slide the rods to release the trigger after a film has been wound by the key post.

5. A combination according to claim 4 characterized by said cam lying in a plane and means adjacent the cam for retaining the offset arms in the plane of the cam whereby either or both offset arms may be moved by said spring into contact with said cam.

6. A combination according to claim 4 in which the slidable rods are enclosed in a housing having walls, the walls of which prevent material flexing of the ofiset arms adjacent the cam, said walls being spaced about the trigger to permit the flexing of the offset arms adapted to engage the trigger and sleeve.

'7. A combination according to claim 4 in which all the offset arms of the slidable rods normally lie fiat against a camera wall, said arms adjacent said cam being held against movement and said arms adjacent said trigger being permitted to distortional movement from their normal position of rest.

8. A combination in accordance with claim 4 in which each slidable rod is slidably mounted and retained against rotative movement near one end thereof whereby tension may be stored in said rod through the trigger and collar moving one offset arm through engagement therewith, said cam sliding said arm to release the trigger and collar permitting the stored-up energy in said arm to move from its contact with the trigger when released from its position between the trigger and collar.

9. A double exposure prevention device for cameras comprising, in combination, a, camera, a film winding key post carried thereby, a cam on the key post, a shutter,- a trigger having a shoulder thereon and movable to and from a position for actuating the shutter, a collar slidably mounted on and encircling the trigger, a spring normall holding the collar in a position spaced from the shoulder when said trigger and collar are in a normal position of rest, a pair of resilient slidable members each having a cam engaging portion and a portion for engagement with the collar and trigger and forming a means for restraining movement of the trigger when said portion lies between the shoulder and collar, a slideway on the camera wall for guiding the slidable members through limited movement to and from the cam and trigger and in which the slidable members tend to lie with the portions for engaging the trigger and collar substantially flat on the camera wall due to the resiliency of said slidable members, spring means for moving the slidable members toward the cam on the key post, said cam moving the slidable members against the action of said spring and being adapted to disengage the portions for engaging the trigger and collar from the locking engagement therebetween.

10. A double exposure prevention device for cameras comprising, in combination, a camera, a film winding ke post carried thereby, a cam on the key post, a shutter, a trigger having a shoulder thereon and movable to and from a position for actuating the shutter, a collar slidably mounted on and encircling the trigger, a spring normally holding the collar in a position spaced from the shoulder when said trigger and collar are in a normal position or rest, a pair of resilient slidable members each having a cam engaging portion and a portion for engagement with the collar and trigger and forming a means for restraining movement of the trigger when said portion lies between the shoulder and collar, a slideway on the camera wall for guiding the slidable members through limited movement to and from the cam and trigger and in which the slidable members tend to lie with the portions for engaging the trigger and collar substantially hat on the camera wall due to the resiliency of said slidable members, spring means for moving the slidable members toward the cam on the key post, said cam moving the slidable members against the action of said spring and being adapted to disengage the portions for engaging the trigger and collar from the restraining engagement therebetween, the cam on the key post extending from the key post through less than 180 degrees whereb operation of the key post and cam may operate first one slidable member and then the other slidable member enabling one of the portions of the two slidable members to be disengaged from the trigger and collar in advance of the other.

11. A double exposure prevention device for cameras comprising, in combination, a camera, a film winding key post carried thereby, a cam on the key post, a shutter, a trigger having a shoulder thereon and movable to and from a position for actuating the shutter, a. collar slidably mounted on and encircling the trigger, a spring normally holding the collar in a position spaced from the shoulder when said trigger and collar are in a normal position of rest, a pair of resilient slidable members each having a cam engaging portion and a portion for engagement with the collar and trigger and forming a means for restraining movement of the trigger when said portion lies between the shoulder and collar, a slideway on the camera wall for guiding the slidable members through limited movement to and from the cam and trigger and in which the slidable members tend to lie with the portions for engaging the trigger and collar substantially flat on the camera wall due to the resiliency of said slidable members, spring means for moving the slidable members toward the cam on the key post, said cam moving the slidable members against the action of said spring and being adapted to disengage the portions for engaging the trigger and collar from the restraining engagement therebetween, said portion of each slidable member being moved from between the trigger shoulder and collar whereby the resiliency of the slidable member may cause said portion of the disengaged slidable member to snap down against the camera wall upon being moved by the cam to release its restraining movement effect upon the trigger.

12. A double exposure prevention device for cameras comprising, in combination, a camera, a film winding key post carried thereby, a cam on the key post, a shutter, a trigger having a shoulder thereon and movable to and from a position for actuating the shutter, a collar slidably mounted on and encircling the trigger, a spring normally holding the collar in a, position spaced from the shoulder when said trigger and collar are in a normal position of rest, a pair of resilient slidable members each having a cam engaging portion and a portion for engagement with the collar and trigger and forming a means for restraining movement of the trigger when said portion lies between the shoulder and collar, a slideway on the camera wall for guiding the slidable members through limited movement to and from the cam and trigger and in which the slidable members tend to lie with the portions for engaging the trigger and collar substantially fiat on the camera wall due to the resiliency of said slidable members, spring means for moving the slidable members toward the cam on the key post, said cam moving the slidable members against the action of said spring and being adapted to disengage the portions for engaging the trigger and collar from the locking engagement therebetween, said trigger and collar being adapted to pass through the camera wall upon actuating the shutter a suflicient extent for a portion of the slidable member to engage only the trigger when the latter is in a fully depressed shutter actuating position whereby said portion of the slidable member may, upon return movement of the trigger and collar, enter between the shoulder and trigger to prevent a shutter actuating movement of the trigger, said cam on the key post being adapted to release such movement restraining engagement.

MILLER R. HUTCHISON, JR.

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