US3864700A

US3864700A - Diaphragm adjusting mechanism for photographic cameras

Info

Publication number: US3864700A
Application number: US471367A
Authority: US
Inventors: Bodo Mielke
Original assignee: Rollei Werke Franke und Heidecke GmbH and Co KG
Current assignee: Rollei Werke Franke und Heidecke GmbH and Co KG
Priority date: 1974-05-20
Filing date: 1974-05-20
Publication date: 1975-02-04
Anticipated expiration: 1992-02-04

Abstract

Mechanism controlled by a photoelectric converter, for setting a camera diaphragm at the proper aperture for optimum exposure, under prevailing illumination conditions. Upon depression of a release plunger to start the exposure cycle, the diaphragm which was previously at maximum aperture is closed down to minimum aperture and at the same time an aperture value storage member is moved from its maximum aperture storage position toward its minimum aperture storage position, but is stopped on the way by an arresting latch controlled by a photoelectric converter, in a position corresponding to the proper aperture for the exposure under prevailing light conditions, although the diaphragm itself continues to close down to minimum aperture. Approximately when the diaphragm reaches minimum aperture, it is released and springs back to the aperture set on the aperture value storage member, which is stationary at this time. The camera may then continue with the exposure cycle, to open and close the shutter to make the actual exposure, while the release plunger is still held depressed by the operator. When the release plunger is released by the operator and returned to its initial position the other parts are restored to their initial positions. A separate plunger constituting a measurement key may be depressed if it is desired to see what the automatically selected aperture value would be, without actually making an exposure.

Description

United States Patent [191 Mielke 51 Feb. 4, 1975 1 DIAPHRAGM ADJUSTING MECHANISM FOR PHOTOGRAPHIC CAMERAS Bodo Mielke, Wolfenbuttel, Germany [73] Assignee: Rollei-Werke Franke & Heidecke,

Braunschweig, Germany 22 Filed: May 20,1974

21 Appl. No.: 471,367

[75] Inventor:

Primary Examiner-Samuel S. Matthews Assistant Examiner-J. A. LaBarre Attorney, Agent, or Firm-Stonebraker & Shepard [57] ABSTRACT Mechanism controlled by a photoelectric converter,

for setting a camera diaphragm at the proper aperture for optimum exposure, under prevailing illumination conditions. Upon depression of a release plunger to start the exposure cycle, the diaphragm which was previously at maximum aperture is closed down to minimum aperture and at the same time an aperture value storage member is moved from its maximum aperture storage position toward its minimum aperture storage position, but is stopped on the way by an arresting latch controlled by a photoelectric converter, in a position corresponding to the proper aperture for the exposure under prevailing light conditions, although the diaphragm itself continues to close down to minimum aperture. Approximately when the diaphragm reaches minimum aperture, it is released and springs back to the aperture set on the aperture value storage member, which is stationary at this time. The camera may then continue with the exposure cycle, to open and close the shutter to make the actual exposure, while the release plunger is still held depressed by the operator. When the release plunger is released by the operator and returned to its initial position the other parts are restored to their initial positions. A separate plunger constituting a measurement key may be depressed if it is desired to see what the automatically selected aperture value would be, without actually making an exposure.

17 Claims, 4 Drawing Figures PATENIEU FEB 4197s SHEU 1 OF 4 PATENTEU FEB 41973

sum

2 or 4 DIAPHRAGM ADJUSTING MECHANISM FOR PHOTOGRAPI-IIC CAMERAS BACKGROUND OF THE INVENTION In many cameras known in the art, there is provision for automatically setting the diaphragm aperture in accordance with prevailing light conditions as determined by a photocell or photoelectric converter. Usually the diaphragm aperture setting is influenced not only by the prevailing light reflected from the object being photographed, but also by the shutter speed (exposure duration) which the operator has already set, and by the film sensitivity or film speed which the operator also has previously set. Sometimes the shutter speed is not preselected by the operator, but is also automatically set by the camera mechanism, certain shutter speeds being associated with certain diaphragm apertures, in what is often called a programmed shutter. All of this is well known in the art, and need not be further explained here. The present invention deals merely with the mechanism for setting the diaphragm aperture, the relation of the diaphragm setting mechanism to other parts of the camera being conventional and well understood in the art, and not here shown.

In known cameras, especially of the single lens mirror reflex type, with so-called automatic diaphragm system, when the camera release or trigger is operated the diaphragm aperture is gradually reduced until the quantity of light passing through the diaphragm aperture and striking the photoelectric converter placed behind the diaphragm is just right for the optimum exposure of the photographic image. At that moment, the diaphragm closing movement is stopped, upon a signal given by the photoelectric converter.

Since the diaphragm setting must take place in minimum time, the diaphragm drive is usually equipped with relatively strong spring power to provide great closure force necessary for rapid operation. Under such conditions, the rapid stopping of the diaphragm closing movement involves several problems which are difficult to solve mechanically. In order to have exactly the right exposure, it is indispensable that the diaphragm setting be very exact. Therefore the diaphragm must be halted in exactly the right aperture position, at the moment when the stopping signal is given by the photoelectric converter, and without any over-swinging of the diaphragm. Because of the great closure force used, this can be achieved only with very great technical expense. As an example, it has been proposed to stop the diaphragm closure movement with a certain advance allowance, the stopping signal being given a little before the diaphragm reaches the desired aperture, so that the slight overrun or over-swinging of the diaphragm will bring it to exactly the desired position. However, such a device is quite complicated, and frequently does not work with sufficient exactitude.

The present invention deals with this problem of producing a camera with automatic diaphragm control, and the main object of the invention is to produce such a camera in a generally improved and more satisfactory form, having a rapid, exact, and wear-free stopping of the diaphragm blades at the proper aperture value measured by means of a photoelectric converter.

Another object of the invention is the provision of relatively simple and inexpensive means for carrying out the above mentioned object.

SUMMARY OF THE INVENTION According to the present invention, the above mentioned objects are accomplished by providing a drive which closes the diaphragm from maximum aperture to minimum aperture, and at the same time moves an aperture value storage member in a direction toward storage of minimum aperture value. When the closing movement of the diaphragm reaches an aperture which is just right for the exposure, as determined by the photoelectric converter situated behind the diaphragm and receiving light through the aperture of the diaphragm, the movement of the aperture value storage member is stopped, which can be accomplished very accurately because the aperture value storage member is small and light and has relatively low inertia so that it can be easily stopped without the problems of stopping rapidly moving parts of higher inertia. The diaphragm mechanism itself, however, continues to move to minimum aperture, leaving the aperture value storage member behind at the proper point. Then when the diaphragm mechanism reaches its minimum aperture, it springs back and opens up to the aperture value determined by the storage member which is now stationary. Then, while the release member or trigger is still depressed, the camera goes through the rest of the exposure cycle, opening and closing the shutter (not here illustrated nor described in detail) to make the actual exposure. When the trigger or release plunger is released by the operator and returned toits initial or starting position, the diaphragm opens up again to maximum aperture, the aperture value storage member returns to its starting position at a maximum aperture value, and the I other parts return to their initial positions.

This arrangement has the great advantage that for the setting of the diaphragm value selected by the photoelectric converter, it is no longer necessary to stop the diaphragm drive with a closing force of about 250 grams, but only the slight force of the return member opening the diaphragm to the aperture value determined by the storage member, after the controlled closing has taken place, the force at this time amounting to only a few grams. This can be effected with simple mechanical means, for example merely a stop, without occurrence of the disadvantages previously mentioned.

In a further development of the invention, in the case ofa diaphragm which is adjusted by means of a plunger movable axially (that is, movable in a direction parallel to the optical axis) the aperture value storage member is formed as what may be called a slideway having a cam-like surface cooperating with the plunger. The slideway may be a longitudinally movable member, but preferably is in the form of a rotationally movable member, such as a rotary disk, and is held fast at the desired point in its movement, by an arresting device actuated by the photoelectric converter. The arresting device preferably consists of an electromagnetically operable lever which can be swung into teeth on one edge of the aperture value storage member (the slideway disk) to stop its further movement. This arrangement has the advantage that if the slideway disk is made of appropriate size, a very fine tooth division can be provided on it, so that a very exact setting of the diaphragm aperture is possible.

In a further development of the invention, if it is desired to be able to read the diaphragm aperture which is determined by the photoelectric converter, without actually making an exposure, the diaphragm drive can be liberated by a measurement key or second plunger rather than the main plunger or trigger which initiates the exposure cycle. When such a measurement key is used, a decoupling device is operable at the end of the stroke of the measurement key, to uncouple the diaphragm adjustment parts from the aperture value storage member so that the diaphragm may immediately return to full or maximum aperture while the storage member remains in its set position. The operator may then observe the diaphragm value determined by the photoelectric converter, since the storage member is still in its adjusted position, but the return of the diaphragm to full or maximum aperture position enables the operator immediately to observe again the scene to be photographed, with maximum brilliance of the image on the screen, assuming that this device is employed in a single lens mirror reflex camera.

Preferably this decoupling can be produced in a simple manner by making the slideway disk or value storage member displaceable axially by the measurement key near the end of its stroke, to carry the slideway disk out of cooperative relation to the plunger which controls the diaphragm aperture.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic side elevational view of diaphragm adjusting mechanism according to one embodiment of the present invention, showing the parts in a state of rest, with the diaphragm fully open;

FIG. 2 is a similar view showing the diaphragm closed to minimum aperture and the aperture value storage member stopped at an intermediate position, with a stored diaphragm aperture;

FIG. 3 is a similar view with the aperture value storage member in the same position illustrated in FIG. 2, and with the shutter opened up from minimum aperture to the aperture value indicated by the storage member, this view also illustrating a measurement key in addition to the release plunger or trigger; and

FIG. 4 is a schematic elevation of some of the parts shown in FIG. 3, viewed from a position at right angles to the direction of view in FIG. 3, with some parts omitted.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIGS. 1 and 2 of the drawings, the diaphragm is shown schematically at l. The aperture of the diaphragm is adjusted by longitudinal movement of the plunger or rod 2 located in the optical unit, which in turn is operated longitudinally by a plunger or rod 3 located in the camera body, both plungers moving axially, that is, in a direction parallel to the optical axis. The optical unit (containing the lens, the adjustable diaphragm, and possibly but not necessarily also the shutter) may be mounted either permanently or detachably and interchangeably on the front of the camera, both arrangements being well known in the art and being conventional, so are not here illustrated. The connection from the plunger 2 to the diaphragm is indicated schematically by the broken line 4! Such a connection is also well known in the art, and is not illustrated here in detail. Suffice it to say that the diaphragm is spring biased in an opening direction, so tends to stay at maximum aperture OI returned IO maximum aperture when plunger 2 serves to reduce the aperture, against the force of the spring bias. The range of axial'movement of the push rod 2 is indicated by the distance between the

broken lines

43 and 45 in FIGS. 1-3; When the rear end of the plunger 2 is at the line 43, the diaphragm l is at maximum aperture, as indicated inFlG. I. When the rear end of the plunger 2 has been pushed forwardly to the line 45, then thediaphragm I is at minimum aperture, as indicated in FIG. 2.

Behind the diaphragm l and in position to receive light entering through the aperture of the diaphragm, there is a photoelectric converter 4 of conventional construction which measures the quantity of light and, through a known formof control circuit indicatedschematically at 5, produces a signal for actuating an arresting device to stop the motion of an aperture value storage member, further described below. This signal is given'when the light coming through the aperture of the diaphragm is at just the right amount necessary for optimum exposure, in view of thespeed or sensitivity of thefilm being used in the camera, and the shutter speed, these factors having been previously set by the operator in a conventional manner well known in the I art.

the camera body in alignment with the plunger 2 in the optical element, so as to be able to press forwardly on the rear end of the plunger 2, is. biased by a return spring 28 which tends to keep the plunger 3 at the rear end of its range of travel. This plunger is coupled through a pin 7a and slot 7b with a plunger displacement lever 8 which is pivotally mounted at 14 to swing forwardly and rearwardly, carrying the plunger 3 with riphery of a rotating pawl 18 mounted on a spindle 23.

A pivot lever 9 is mounted to swing on the same pivot 14, and lies alongside of the lever 8. The left end of the lever 9 (when viewed as in FIG. I) is in the path ,of travel of the release plunger or trigger plunger I0 of the camera, so that when this plunger 10 is depressed, it will swing the lever 9 counterclockwise on its pivot 14, against theforce ofa spring 13 which tends to keep this lever at the clockwise limit of its travel. .Near the right hand end of the lever 9, a pawl 15 is pivoted to the lever, and is biased in a counterclockwise direction by the spring 16. One end of this pawl engages under a projection 8a on the plunger displacement lever 8, so that when this pawl 15 is raised by downward pressure of the trigger or release 10 on the opposite end of the lever 9, the action of the pawl will carry the plunger displacement lever 8 upwardly with it. But just as the

levers

8 and 9 are about to reach the limit of their travel in a counterclockwise direction (upwardly as in FIGS. 1 and 2) the other end or tail of the pawl 15 engages a fixed stop 15b which swings the pawl clockwise on its pivot against the action of its spring 16, and releases the engagement with the plunger displacement lever 8, as illustrated in FIG. 2. The lever 8 and its plunger 3 coupled thereto are then free to return downwardly (viewed as in FIGS. 1 and 2) under the influence of the return spring28, independently of the downward return movement of the lever 9 and pawl 15.

The gear segment member or lever 17 is pivoted on the same pivot 14 and a laterally extending projection or ear 17a overlying both of the

levers

8 and 9, and a gear tooth segment 17h concentric with the pivot 14. The segment 17b meshes with gear teeth 18a on the pe- The above mentioned plunger 3 which is mounted in I in which position the pawl is held by a detent device in- I On the same spindle 23 on which the pawl 18 is v mounted, there is a cylinder 20 and an aperture value storage member 22, sometimes referred to as a slideway disk. The pawl 18 is coupled to the storage member 22 by means of a coiled spring 21 lying on the periphery of the cylinder 20, one end of the spring being fixed to a pin on the pawl 18, and the other end of the spring being fixed to a pin on the aperture value storage member 22, to tend to turn the pawl counterclockwise and the storage member clockwise relative to each other, to a limit position determined by a pin 22c projecting axially from the storage member 22 into a position to engage the pawl 18, as shown in FIG. 1.

One portion of the periphery of the aperture value storage member 22 is formed as a cam engaging a lateral projection 3a on the plunger 3, in position to raise this plunger 3 against the force of itsreturn spring 28, as the member 22 is rotated in a clockwise direction. When the

parts

18 and 22 are in their rest positions shown in FIG. 1, the cam edge of the storage member 22 allows the plunger 3 to be in its lowest position as illustrated in FIG. 1, the diaphragm being at maximum aperture. As the storage member 22 turns clockwise from its rest position, a progressively higher portion of the cam edge of the member 22 underlies the projection 3a on the plunger 3, to limit the extent to which the plunger can return downwardly under the influence of its spring 28. The cam does not actually raise the plunger, for the plunger is raised by the joint action of the

levers

8 and 9, but the cam portion serves as an abutment to stop the subsequent return motion of the plunger 3 after the lever 8 is released from the lever 9 by the releasing action of the pawl 15.

Another portion of the periphery of the aperture value storage member 22 is provided with a series of notches or teeth 22b which cooperate with the tooth on the arresting device indicated in general at 6. As above stated, it is preferred to make the storage member 22 of sufficiently large diameter and to make the teeth 22b sufficiently fine so that the angular increment from one tooth to the next is quite small, thus enabling a very fine adjustment of the position of the member 22 as determined by engagement of the arresting device with the teeth.

The arresting device preferably comprises a pivoted lever or pawl 6a, biased in a clockwise direction by a spring 6b, so that the pointed opposite end of the pawl is out of engagement with the teeth 22b. The pawl is swung against the action of its spring 6b by electromagnetic operating mechanism, to swing the point on the pawl into engagement with the teeth 22b.

The electromagnetic means for swinging the arresting pawl 6a is preferably in the form of an electromagnetic device employing a pot-shaped magnet. Such a magnet may be in the form disclosed in the present ap- 1973, there shown in connection with a drive for the blades of a photographic shutter, or in the present applicants US. Pat. No. 3,812,501, granted May 21, 1974 on copending application US. Pat. No. 335,914, there shown in connection with a drive for a diaphragm. Such a pot-shaped magnet, here illustrated schematically at 60, constitutes a convenient and efficient way to operate the arresting pawl 6a, but any other suitable electrical or electromagnetic operator for the arresting pawl may be used if desired. The only requirement is that when the photoelectric converter 4 in conjunction with the conventional control circuit 5 give the signal that just the right amount oflight is coming through the diaphragm for the correct exposure. the arresting pawl should immediately engage the teeth 22b of the aperture value storage member 22, to store in this member the value to which the diaphragm aperture should be set a moment later, when it has.

completed its closing movement to minimum aperture and then starts to open up again.

The storage member 22 is connected through a draw cable 24 with an indicator device from which the operator can read the aperture value corresponding to the position of the storage member 22. Such device is here shown schematically as a pointer 25 mounted on and moving with the draw cable 24, and traveling along a graduated scale graduated in terms of the usualfnumbers. A light spring 47 keeps the draw cable 24 taut, the power of this spring being relatively slight and not sufficient to overcome the power of the spring 29 which tends to turn the segment lever 17 in a clockwise direction and therefore to act on the storage member 22 in a direction opposite to the pull of the light spring 47.

When the parts are in the rest position illustrated in FIG. 1, an extension 9a on the lever 9 engages the detent pawl 19a and holds it, against the force of its spring 19b, in a position out of alignment with the pawl 18, so that the pawl 18 can return to its rest position. When the lever 9 swings upwardly (counterclockwise on its pivot 14) the extension 9a releases the detent pawl 19a so that, when the pawl 18 comes around, it displaces and snaps past the detent pawl 19a and is held in that position by the detent pawl, as illustrated in FlG. 2. This extension arm 9a on the lever 9 also has a gear segment 9b meshing with the teeth on a gear and escapement train 26, 27 of the conventional form commonly used as retarding means in the photographic shutter art. This

retarding mechanism

9b, 26, 27 serves to slow down the return movement of the lever 9 under the influence of its spring 13, to allow adequate time for completion of the exposure cycle if the operator happens to take his finger off of the trigger plunger 10 very I promptly, before the exposure cycle has been complicants US. Pat. No. 3,724,350, granted Apr. 3,

pleted. The retard mechanism also provides a constant or uniform closing speed for the diaphragm drive mechanism.

The construction above described operates as follows:

Upon actuation of the trigger member or release knob 10, the pivot lever 9 is swung in the direction of the arrow A, counterclockwise on its pivot 14, against the force of the return spring 13. The pawl 15 at the right hand end of this lever 9, engaging under the portion 8a of the plunger lever 8, moves the plunger lever 8 in the same direction, counterclockwise on the pivot 14, and through the pin and slot connection 7a, 7b, this displaces the camera plunger 3 upwardly in the direction of the arrow B. The plunger 3 thus pushes against the end of the diaphragm plunger 2, closing down the diaphragm from maximum aperture in FIG. 1, to minimum.aperture as shown in FIG. 2, when the rear end of the diaphragm plunger 2 moves through its full range of travel from the line 43 to the line 45.

As this movement takes place, the aperture value storage member is turned clockwise on its spindle, because the gear segment member 17, moving with the lever 9 and meshing with the teeth on the pawl 18, swings this pawl clockwise and the storage member 22 turns clockwise with it, pulled by the spring 21, until the moment that, during the closing down of the diaphragm aperture, the photoelectric converter 4 senses the correct amount of light for the exposure. This gives the signal to operate the arresting device 6 which, entering the teeth 22b on the member 22, stops the rotation of the storage member 22 at this point, although the pawl 18 continues its clockwise rotation to the full end of its'stroke, stretching the spring 21 because the member 22 has stopped rotating.

At the end of the stroke of the plunger 3, the rotating pawl 18 has moved to its limit position where it is held by the detent 19a as in FIG. 2, even though the storage member 22 has been stopped by the arresting device 6 at some intermediate point of its travel. Just as the pawl 18 is reaching the end of its travel and the lever 9is reaching the end of its counterclockwise swing, the tail of the pawl engages the stop 15b and releases the nose of the pawl from the lever 8, so, that the lever 8 now moves in a clockwise direction, bringing the plunger 3 back with it under the influence of the plunger return spring 28, until the projection 3a on the plunger comes to rest on the edge of the cam portion of the aperture value storage member 22. The diaphragm plunger 2 follows the return movement of the camera plunger 3 on account of the spring bias in the diaphragm mechanism which tends to open the diaphragm to maximum aperture, and in this way the diaphragm .is set to whatever aperture position is determined by the height of the cam edge of the member 22, serving as a stop or abutment for the projection 3a on the plunger 3. g

The camera shutter is now opened and closed again, to make the actual exposure, by conventional mechanism well known in the art and not here illustrated. The value of the diaphragm aperture which was set can be read by the operator by means of the index mark 25 with relation to the diaphragm aperture scale.

After the pressure exerted on the release knob or 'trigger plunger 10 is removed, the spring 13 moves the .on the segment member 17 which is pivoted on the same pivot 14 with the

levers

8 and 9. On account of the ear 17a on this member 17 overlying the

levers

8 and 9, the segment was pulled upwardly, against the force of the spring 29, when the

levers

8 and 9 were moved upwardly ina counterclockwise direction by the pressure of the trigger l0, and when these levers move downwardly again, the segment member 17 is free to swing downwardly as soon asthe detent 19 is released by the end of the downwardly swinging lever 9, so that the rotating pawl 18 can begin its return movement in a counterclockwise direction. During this return movement, the pawl 18 picks up the pin 22c on the storage member 22, and carries the storage member back in a counterclockwise direction. This movement is possible because the electric current of the arresting device 6c has been switched off in known manner at the conclusion of the exposure, and the spring 6b moves the nose of the arresting member'6a out of the-teeth 22b of the storage member, thus freeing the storage member for counterclockwise rotation under the influence of the spring 29, back to its initial starting position. The spring 29 is substantially stronger than the spring 47. A sec ond embodiment constituting a slight variation of the first embodiment will now be described in connection with FIGS. 3 and 4. The operation when making'an exposure is exactly the same as above described in connection with the first embodiment. However, in this second embodiment there is what may be called a measurement key or measurement plunger 11, in addition to the regular release or trigger plunger 10. When the measurement key 11 is depressed, the mechanism goes through the operations necessary for measuring the appropriate diaphragm aperture, but does not actually make the exposure. In this way the operator can learn what the appropriate diaphragm aperture for the contemplated exposure may be, and if he is not satisfied with this aperture (e.g., if he wants a greater or smaller depth of field) hecan readust the shutter speed setting and then again make a test to see what the aper ture would be at the new shutter speed setting.

Immediately after making such a test of the diaphragm'aperture, the diaphragm should again open to maximum aperture to enablethe operator again to observe the field of view, with the brightest possible image on the viewfinder, particularly if a single lens mirror reflex camera isbeing used. Thepresent modification of the invention, as illustrated schematically in FIGS. 3 and'4, accomplishes this. i 1

A bellcrank lever 12 is mounted in the vicinity of the measurement key or plunger l 1,so that one arm of this bellcrank is engaged and swung by a pin 11a on the plunger 11, when the latter is'depressed. The other arm 12a of the bellcrank then comesdown on top of the pivot lever 9, which is the same as the lever 9 in the previous embodiment, and swings this lever counterclockwise on its pivot 14 in the same way that it would be swung by the release plunger 10, except that when the plunger 10 is not actuated, the mechanism is not effective to open and close the shutter to make an exposure. The entire measurement operation takes place when the measurement plunger 11 is operated, just as before described, up to the point of reaching the maximum swinging movement of the lever 9.

A supplementary lever 30, only the left end of which is shown in FIG. 3, is pivoted at an intermediate point, and the left end is in position to be engaged and swung by the measurement plunger 11. In this embodiment,

the spindle 23 projects at its right end as seen in FIG.

The first part of the downward movement of the 7 measurement key 1 l operates the bellcrank 12 to swing the lever 9 through its maximum swinging range in a counterclockwise direction, lifting the plunger 3 and then releasing it to come back against the storage member 22, thus giving a diaphragm aperture indication just as described in connection with the earlier embodiment. Then a little further depression of the measurement key 11 has no further effect on the lever 9, but does engage the left end of the supplementary lever 30, swinging the right end upwardly from the full line position to the dotted line position shown in FIG. 4. The angular or cranked end of this lever 30 acts like a cam on the end of the spindle 23, and moves the spindle 23 and with it the storage member 22 leftwardly from the full line position to the dotted line position. In this latter position, the storage member 22 is displaced laterally away from the projection 3a on the plunger 3, so that the plunger is immediately free to complete its return movement so that the diaphragm will open to maximum aperture, without waiting for the return movement of the other parts of the mechanism.

When the pressure on the measurement key or plunger 11 is released, all of the other parts return to their original startingpositions in exactly the same way described above in connection with the first embodiment, except that the camera plunger 3 and diaphragm plunger 2 have already returned to their initial or maximum aperture positions, as above described. As the return movement is being completed a suitable spring, not shown, returns the spindle 23 and aperture value storage member 22 axially in a rightward direction when viewed as in FIG. 4, from the dotted line position to the full line position.

What is claimed is:

1. Exposure controlling mechanism for photographic cameras, comprising a diaphragm having an adjustable aperture, an aperture value storage member movable to different positions representing different diaphragm apertures, diaphragm drive means effective upon actuation to close the diaphragm down from maximum aperture to minimum aperture, positioning means including a photoelectric converter effective during the closing down of the diaphragm to position said storage member in a position representing an optimum aperture for an exposure, and return means for opening the diaphragm up to an aperture corresponding to the position of saidstorage member.

2. The invention defined in claim 1, wherein said drive means includes a longitudinally movable plunger (3), said storage member (22) includes a cam portion cooperating with said plunger, and said return means includes a spring (28) tending to move said plunger into engagement with said cam portion.

3. The invention defined in claim 2, wherein said drive means includes means (9, l5, 8) for driving said plunger (3) through a full stroke in a diaphragm closing direction and then releasing said plunger so that said spring (28) may move said plunger in a reverse direction to a position determined by the cam portion of said storage member (22).

4. The invention defined in claim 1, wherein said aperture value storage member (22) has a series of recesses (22b), and said positioning means includes an arresting pawl (6a) movable into one of said recesses under the control of said photoelectric converter (4) to hold said storage member in said optimum aperture representing position. v

5'. The invention defined in claim I, wherein said storage member is a rotatable disk (22), and said drive means includes a rotatable pawl (18), and there is a spring (21) resiliently coupling said disk to said pawl.

6. The invention defined in claim 5, wherein said spring (21) tends to move said disk with said pawl when said pawl rotates in one direction, and wherein said disk has an abutment pin (22c) engaged by said pawl when the pawl rotates in the opposite direction, to turn the disk positively in such direction.

7. The invention defined in claim 5, further including a latching detent (19a) for holding said rotatable pawl (18) substantially at the end of its rotary movement in a direction corresponding to decreasing diaphragm aperture.

8. The invention defined in claim 5, further comprising a gear segment member (17) moving with said diaphragm drive means, said rotatable pawl (18) having gear teeth meshing with gear teeth on said segment member to turn said pawl upon movement of said drive means in an aperture decreasing direction.

9. The invention defined in claiml, wherein said drive means includesa longitudinally movable plunger (3), and said return means includes a spring (28) tending to move said plunger in an aperture increasing direction, and operation of said drive means serves to displace said plunger against the force of said spring through a full stroke from its maximum aperture position to and slightly beyond its minimum aperture position and then to release said plunger in its last mentioned position so that said spring may move said plunger in aperture increasing direction.

10. The invention defined in claim 9, wherein said drive means includes a drive lever (9), a plunger displacement lever (8) having a pin and slot connection (7a, 7b) with said plunger, a pivoted pawl (15) mounted on said drive lever for engaging said plunger displacement lever to cause said displacement lever to move with said drive lever during a stroke of the latter in aperture decreasing direction, and a stop (15b) for engaging said pawl to release it from said plunger displacement lever substantially at the end of said stroke of said drive lever.

11. The invention defined in claim 10, further comprising a rotatable pawl resiliently coupled to said value storage member to tend to move said storage member upon movement of said pawl, gear teeth on said pawl, and a gear segment lever having teeth meshing with the gear teeth of said pawl to cause rotary movement of the pawl upon swinging movement of said segment lever, said segment lever, said drive lever, and said plunger displacement lever being mounted for swinging movement about a common axis, and a projection (17a) on said segment lever overlying a portion of said plunger displacement lever in such position that swinging said displacement lever in an aperture reducing direction will swing said segment lever with it, thereby to rotate said pawl.

12. The invention defined in claim 7, further comprising means effective upon return of part of said diaphragm drive means to a rest position for unlatching said detent (19a) so that said rotatable pawl (18) may return to its rest position.

13. The invention defined in claim 10, further comprising a rotatable pawl (18) for moving said aperture value storage member (22), a latching detent (19a) for holding said rotatable pawl substantially at the end of its rotary movement in a direction corresponding to decreasing diaphragm aperture, and a portion (9a) on said drive lever 9) for engaging said latching detent and unlatching the same as said drive lever returns to its rest position after a stroke in an aperture reducing direction.

14. The invention defined in claim 1, further comprising a measurement key operable to actuate said drive means for aperture determining purposes without making a photographic exposure, and means operated by said key for de-coupling said drive means from said storage member so that said return means may immediately open the diaphragm to its maximum aperture regardless of the position of said storage member.

15. The invention definedin claim 3, further com- 12 prising a measurement key (11) operable to actuate said drive meansfor aperture determining purposes without making a photographic exposure, and means operated by said key for rendering said storage member (22) ineffective to limit the reverse movement of said plunger. l

16. The invention defined in claim 15, wherein said storage member is in the form of a rotary disk having a cam portion aligned with and serving as an abutment for a portion of said plunger, and a lever operable by said measurement key for displacing said rotary disk in an axial direction to move said cam portion thereof out of alignment with said portion of said plunger.

17. The invention defined in claim I, further comprising indicating means for indicating the position of said storage member in terms of aperture values, so that when said diaphragm drive means has been actuated, the resultant aperture value can be read.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,86 h7 Dated ry 1975 Inventor(s) BOdO Mielke It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the Cover Sheet, the following should be added:

Foreign Application Priority Data July 13, 1975 Germany P 25 55 603.8

Signed and sealed this 22nd day of April 1975.

(SEAL) Attest:

C. MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officer and Trademarks FORM PO-1 USCOMM-DC 60376-P69 u.s. eovzmmzm PRINTING oFFICE: I

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 5,86 l-,700 Dated February l, 1975 Bodo Mielke Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the Cover Sheet, the following should be added:

Foreign Application Priority Data July 15, 1973 Germany P 25 35 603.8

Signed and sealed this 22nd day of April 1975.

(SEAL) Attest:

C. MARSHALL DANN RUTH C. MASON Commissioner of Patents and Trademarks Attesting Officer FORM PO-105O (10-69) I us GOVERNMENT PRINTING omcz; 86 93 d

Claims

1. Exposure controlling mechanism for photographic cameras, comprising a diaphragm having an adjustable aperture, an aperture value storage member movable to different positions representing different diaphragm apertures, diaphragm drive means effective upon actuation to close the diaphragm down from maximum aperture to minimum aperture, positioning means including a photoelectric converter effective during the closing down of the diaphragm to position said storage member in a position representing an optimum aperture for an exposure, and return means for opening the diaphragm up to an aperture corresponding to the position of said storage member.

3. The invention defined in claim 2, wherein said drive means includes means (9, 15, 8) for driving said plunger (3) through a full stroke in a diaphragm closing direction and then releasing said plunger so that said spring (28) may move said plunger in a reverse direction to a position determined by the cam portion of said storage member (22).

4. The invention defined in claim 1, wherein said aperture value storage member (22) has a series of recesses (22b), and said positioning means includes an arresting pawl (6a) movable into one of said recesses under the control of said photoelectric converter (4) to hold said storage member in said optimum aperture representing position.

5. The invention defined in claim 1, wherein said storage member is a rotatable disk (22), and said drive means includes a rotatable pawl (18), and there is a spring (21) resiliently coupling said disk to said pawl.

9. The invention defined in claim 1, wherein said drive means includes a longitudinally movable plunger (3), and said return means includes a spring (28) tending to move said plunger in an aperture increasing direction, and operation of said drive means serves to displace said plunger against the force of said spring through a full stroke from its maximum aperture position to and slightly beyond its minimum aperture position and then to release said plunger in its last mentioned position so that said spring may move said plunger in aperture increasing direction.

13. The invention defined in claim 10, further comprising a rotatable pawl (18) for moving said aperture value storage member (22), a latching detent (19a) for holding said rotatable pawl substantially at the end of its rotary movement in a direction corresponding to decreasing diaphragm aperture, and a portion (9a) on said drive lever (9) for engaging said latching detent and unlatching the same as said drive lever returns to its rest position after a stroke in an aperture reducing direction.

15. The invention defined in claim 3, further comprising a measurement key (11) operable to actuate said drive means for aperture determining purposes without making a photographic exposure, and means operated by said key for rendering said storage member (22) ineffective to limit the reverse movement of said plunger.

17. The invention defined in claim 1, further comprising indicating means for indicating the position of said storage member in terms of aperture values, so that when said diaphragm drive means has been actuated, the resultant aperture value can be read.