US3587998A - Electric winding device for cameras - Google Patents

Abstract

AN ELECTRIC WINDING DEVICE FOR CAMERAS, WHICH IS CAPABLE OF EITHER A CONTINUOUSLY SHOOTING MODE OF OPERATION, OR A SINGLE-FRAME SHOOTING MODE OF OPERATION. THE WINDING DEVICE HAS A POWER TRANSMISSION WITH A DIFFERENTIAL MECHANISM TO SELECTIVELY TRANSMIT THE OUTPUT POWER OF A MOTOR TO EITHER A FILM TAKEUP SHAFT OR A SWITCH-ACTUATING MEANS. SAID DIFFERENTIAL MECHANISM INCLUDES A CAM MEANS AND DRIVES A FILMWINDING SHAFT WHEN THE LOAD ON THE FILM-WINDING SHAFT IS SMALLER THAN A CERTAIN LOAD PREAPPLIED TO SAID CAM MEANS, WHILE SAID DIFFERENTIAL MECHANISM DRIVES SAID CAM MEANS WHEN SAID LOAD ON THE FILM-WINDING SHAFT IS LARGER THAN SAID CERTAIN LOAD, WHEREBY FILM-WINDING, SHUTTER-CHARGING AND RELEASING ETC. ARE ATTAINED AUTOMATICALLY.

Description

United States Patent [72] Inventors [21 1 Appl. No. [22] Filed [45] Patented [73] Assignec (32] Priority 1 1 1 [S4] ELECTRIC WINDING DEVICE FOR CAMERAS Yoshio Kuramoto;

Kaoru L'meda: Sakai, Osaka, Japan 860,542

Sept. 24, 1969 June 28, 1971 Minolta Camera Kabushiki Kaisha Osaka, Japan Sept. 27, 1968 Japan 3 Claims, 12 Drawing Figs. I

[52] US. Cl

[50] Field of Search References Cited UNITED STATES PATENTS 3,357,780 12/1967 Martin 3,47l,227 10/1969 McClellan et a1 352/169 3,489,493 1/1970 Aoki 352/180 FOREIGN PATENTS 2,756,4/68 8/1965 Japan 242/206 Primary Examiner Leonard D. Christian An0rneyStanley Welder ABSTRACT: An electric winding device for cameras, which is capable of either a continuously shooting mode of operation, or a single-frame shooting mode of operation. The winding device has a power transmission with a differential mechanism to selectively transmit the output power of a motor to either a film takeup shaft or a switch-actuating means. Said differential mechanism includes a cam means and drives a film-winding shaft when the load on the film-winding shaft is smaller than a certain load preapplied to said cam means, while said differential mechanism drives said cam means when said load on the film -winding shaft is larger than said certain load, whereby film-winding, shutter-charging and releasing etc. are attained automatically.

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INVENTOR. 00m: unw osuw m Mmo 0 BY 1 M ELECTRIC WINDING DEVICE FOR CAMERAS This invention relates to an electric winding device, and more particularly to a motor-driven takeup device for motordriven roll film cameras having a differential power transmission means to take up a film and charge and release a shutter, which differential power transmission means is operatively connected to a cam portion applying a first load to the transmission means and a winding portion applying a second load to the transmission means, so as to actuate the winding portion when said first load is smaller than the second load and to actuate said cam portion when the first load is larger than the second load.

In a known automatic winding camera, a film is taken up upon completion of each shooting, and then a driven shaft connected to a film takeup mechanism is subjected by an excessive load and is stopped in its rotation, while a driving shaft is continuously rotated to release a shutter through a lever means. In this case, after the driven shaft is stopped, the portion of the driving shaft where is in contacted with said driven shaft slides against said driven shaft. For instance, Japanese Utility Model Registration No. 823,907, titled An Motor Driven Automatic Winding Device, discloses a winding device having a cam and an intermittent transmission mechanism both driven by a motor for winding a film and charging and releasing a shutter in a motor driven camera. The automatic winding device of the Utility Model comprises a first brake circuit and a second brake circuit both connected in parallel with an electric feeding circuit of the motor for selectively short-circuiting terminals of the motor, said first brake circuit having a first and second two-contact changeover switches connected in series with each other, said first changeover switch being engageable with a first lever to be actuated just before exposure and actuating a release member, said second changeover switch being engageable with a signal control member to be actuated together with a shutter mechanism toward the end of shutter operation, said second brake circuit having a third two-contact changeover switch engageable with a second lever to be actuated by a cam upon completion of winding ofa film, and a shutter, one contacts of said changeover switches being connected to said brake circuits, other contacts of said switches being connected to a power source, whereby when said electric feeding circuit is interrupted by said switches, electric braking is applied to said motor by the operation of said switches.

Another example of known winding devices is disclosed in Japanese Utility Model Publication No. 25,4101966, entitled An Automatic Film-Winding Device for Cameras." The construction of the known automatic film-winding device is such that a driving shaft, frictionally engaged with a driven shaft so as to cause said driven shaft to follow the driving shaft, rotates excessively while slipping due to an excessive load on said driven shaft, whereby a pair of operating levers are actuated by said driving shaft in its excessive rotating range. One of said pair of operating levers selects a manual electric feeding circuit or an automatic electric feeding circuit to a driving motor for winding operation, in response to said actuation by said driving shaft. The other one of said pair of operating levers actuates a shutter release member and an opening and closing switch in said automatic electric feeding circuit. The automatic electric feeding circuit has another switch connected in parallel with said opening and closing switch and adapted to be closed toward the end of shutter closing operation.

However, in each of the above mentioned known motordriven cameras, while the film is taking up, driving parts and driven parts move integrally, and when the winding operation is finished, the loading on the driven part becomes excessively large, while the driving part rotates and moves backward as the contacting portion of the driving part with the driven parts slides on the contacting surface of said driven part, so that the shutter is released and upon completion of each shooting, the release members return and become ready for the succeeding releasing operation. In the above process, the relative portion between the driving part and the driven part is difficult to know, and hence, the timing where the release member returns is also difficult to determine. When the shooting operation is completed, an electric feeding circuit is closed by a last operating member of an exposure mechanism for driving a motor, but it is opened by the camera mechanism without waiting for the completion of film-winding operation. Thus, it is necessary to bypass it by an auxiliary switch at an intermediate moment between the completion of shooting operation and the beginning of film-winding operation. However, it is difficult to exactly complete such bypass circuit in said intermediate moment due to the aforementioned reasons i.e. due to the difficulty of determination of the starting position of the sliding of the driven part and the timing when the release member returns. It will be necessarily a complicated mechanism for controlling the returning of said release member and the timing of the completion of the bypass circuit. Furthermore, in the known device as mentioned above, there occur frequently such a situation that the film is not taken up despite of that the shutter has been closed, when an operator removes his finger from the shutter button before the shutter closing. In other words, said electric feeding circuit of the known device is constructed so that which circuit is closed by cooperation of a first switch which is changed over by means of a last operating member of an exposure mechanism and a second switch which is changed over relative to the movement of the shutter button so that the motor is started and then the bypass circuit is closed. Therefore, if the operator removes his finger from the shutter button before the shutter is closed, i.e. during film exposure, there occur such a situation that the second switch is changed over first. Consequently, the motor is not driven and thus the film is not taken up in spite of the fact that the shutter is closed and the first switch is changed over, and the photographer may miss a chance to make a successful shooting with good timing.

Therefore, an object of the present invention is to obviate the aforesaid difficulties of known cameras. According to the present invention, there is provided a motor-driven takeup device comprising a differential gear means having a planet gear inserted between a film takeup shaft and a motor, so that taking up of the film, charging and releasing the shutter can be carried out depending on the magnitude of load on said shaft. Said differential gear means includes an internal gear having its one end formed into a solid cam, so as to allow any arbitrary presetting of that position where a driving shaft begins to slide. Thereby, the sequence of actuation of the levers, the switches and other mechanisms for taking up the film, charging the shutter and releasing of the shutter is accurately controlled and the aforesaid uncertainty of the initial position of the sliding movement of the driving shaft in known camera mechanism is eliminated. With the device of the present invention, the aforesaid difficulties in an electric circuitry of known cameras is completely eliminated, and there is practically no need for margins in the return stroke of a shutter release member and in the timing of a switching circuit operation. Thus, the taking up time is shortened, and even if the camera is misoperated by a photographer, no trouble of camera mechanism will be caused by it. The operative members of the device of the present invention always stop accurately at the prescribed positions, respectively, and accordingly, there is no chance of disorder in the operating sequence of its various parts, and there is no time loss in its operation. Furthermore, the best timing of shooting, such as shooting of nonreproducible phenomena, can be captured without failure. Moreover, with the device of the invention, the overall dimension of a camera can be made compact and film winding can be made more rapid.

Other objects and a fuller understanding of the present invention may be had by referring to the following description, taken in conjunction with the accompanying drawings, in which;

FIG. I is a schematic plan view of a motor-driven takeup device, according to the present invention;

FIG. 2 is a diagrammatic view of a gear train usable in the device of the present invention;

' FIG. 3 is a schematic view, taken from a direction shown by the line III-III of FIG. 1;

FIGS. 4 and 5 are schematic views similar to FIG. 3, shown at different operative positions thereof, respectively;

FIG. 6 is a diagrammatic illustration of a lever and a switch in the device of FIG. 1, shown on an enlarged scale;

FIG. 7 is a similar view to FIG. 6, illustrating the switch and the lever at a different operative position;

FIGS. 8 to 10 are circuit diagrams of a switching circuit in the device of the present invention, illustrating different operative conditions, respectively;

FIG. 11 is a circuit diagram, showing another embodiment of the present invention; and

FIG. 12 is an expanded view of a solid cam usable in the device of the present invention.

Like parts and members are designated by like numerals and symbols throughout the drawings.

Referring to FIG. 1, illustrating an embodiment of the present invention, a driving motor I has a driving gear 2 secured to its driving shaft, and the driving gear 2 meshes with a gear 3 secured to one end.of a rotary sleeve fitted on a gear shaft 25 pivotally supported by the stationary members of the body. The sleeve has a sun gear 4 coaxially secured thereto at the opposite end'thereof. The gear shaft 25 has a bevel gear 7 secured to one end thereof, so as to mesh with another bevel gear 14 for taking up a film. The gear shaft 25 also has bracket 8 secured there to at an intermediate portion thereof adjacent to the sun gear 4. The bracket 8 carries a planet gear 5, which engages both the sun gear 4 and an internal gear 6 formed on the inner surface of a cylindrical member 6d rotatably supported by the gear shaft 25 and a stationary member 26. The gear train consisting of the sun gear 4, the planet gear 5, and the internal gear 6 acts as a differential gear means. In the particular embodiment shown in the FIGS., ball bearings 6e are inserted between the'stationary member 26 and the cylindrical body 6d to facilitate the rotation of the cylindrical body 6d. The left-hand end of the cylindrical member 6d, as seen in FIG. 1, forms a solid cam 9 having a high portion 6a and a low portion 6b connected to the high portion 6a through steplike slopes 6f, as depicted in the expanded view of FIG. 12. A projection 6c extends outwards from the outer periphery of the cylindrical body 6d at its longitudinal intermediate portion, so that the projection 6c can engage a plate cam 13b secured to an actuating shaft 13 disposed in parallel with the gear shaft 25, as will be described in detail hereinafter.

A switch-actuating lever 10 is pivotally supported by a pin at the upper end thereof and biased counterclockwise around the pin by a spring 11. The switch-actuating lever 10 has a first arm 10a engaging the solid cam 9 and a second arm 10b engaging a head cam plate 13a formed at the left end of the actuating shaft 13, as seen in FIG. 1. The actuating shaft 13 is biased leftwards in FIG. 1, and at the same time, the shaft 13 is biased to rotate in a counterclockwise direction, as seen from the direction of the line III-III. The switch-actuating lever 10 has a third arm 10c engaging a movable contact 12b located at the center of a first switch 12. An L-shape release lever 17 is pivotally supported by a pin at the center thereof and biased clockwise around the pin by a spring 17a, as seen in the FIG. The release lever 17 has an arm 17b engaging a plate cam 13b secured to the actuating shaft 13 at a longitudinal intermediate position thereof. The tail end of the actuating shaft 13 engages a movable contact 16b located at the center of a second switch 16.

A third switch 18 has a central movable contact 18b adapted to engage with a stud 19a secured to an end of a switch actuator 19, which rotates clockwise, as seen in FIG. 1, upon completion ofeach shooting operation. A pair of button operated power source switches 20, 21 are adapted to be connected to an electric power source 24, and a shunt switch 22 is connected in parallel across the power switch 21. A counter switch 23 is connected in series between the driving motor I and the power source 24. Thus a switching circuit is constructed as shown in FIG. 1.

In the motor-driven'takeup device of the aforesaid construction, when the film is not yet taken up and when the first arm 10a of the switch-actuating lever 10 engages the steplike slop 6fof the solid cam 9, as shown by solid lines in FIG. 12, the cylindrical member 6 is prevented from rotating by such engagement between the arm 10a and the slope 6f. In this case, a load on the cylindrical member 6 is larger than that on a film take up shaft 14a. Thus, the rotation of the driving motor 1 is transmitted to the film-winding bevel gear 14 through the driving gear 2, the transmitting gear 3, the sun gear 4, the planet gear 5, and the bevel gear 7, so that the film takeup shaft 140 is rotated to take up a film. On the other hand, if the film takeup shaft 14a is locked against rotation after the film has been taken up (in this case the load on the cylindrical member 6 is smaller than that on the film takeup shaft 14a), namely just before the exposure of the film, the switch-actuating lever 10 is rotated in the clockwise direction by the solid cam 9 of the body 6d which is rotated by the driving motor 1 through the driving gear 2, the transmitting gear 3, the sun gear 4, the planet gear 5, and the internal gear 6, as will be described hereinafter. In this condition, the first arm 10a of the switch-actuating .lever 10 engages the high portion 6a of the solid cam 9.

FIGS. 3 to 5 are end views of the cylindrical member 6d and the actuating shaft 13, as seen from the direction of the line III-III of FIG. 1, i.e. from the side of the film takeup shaft 14a. When the cylindrical member 6d is rotated by the engagement of the internal gear 6 with the planet gear 5 so as to bring the low portion 6b of the solid cam 9 into contact with the firs arm 10a of the switchactuating lever I0, the lever 10 moves counterclockwise by the elasticity of the spring 11, as seen in FIG. 1. Thereby, the second arm 10b of the switch-actuating lever 10, engaging the head cam plate 13a integrally formed with the actuating shaft 13, forces the actuating shaft 13 rightwards, as seen in FIG. 1, against the elasticity of the spring 15. Accordingly, the plate cam 13b secured to the actuating shaft 13 and engaging a tail portion 17b of the release lever 17, causes the release lever 17 to rotate counterclockwise, as seen in FIG. 1, so that a head portion 17c of the release lever acts to release a shutter (not shown). At the same time, the right-hand end of the actuating shaft 13 shifts the movable contact 16b of the second switch 16 from its stationary contact 16a to its another stationary contact 160, while the third arm of the switch-actuating lever 10 moves rightwards to allow the movable contact 12b of the first switch to move away from its stationary contact 12a and come into operative contact with its another stationary contact 120, as depicted in FIG. 6.

The plate cam 13b moves further rightwards to intercept the locus of the rotation of the projection '60 issuing from the cylindrical body 6d. The movable contact 18b of the third switch 18 is normally kept in contact with the lower stationary contact 18a. At the end of each shooting, the switch actuator 19 is rotated clockwise, as seen in FIG. 1, by a suitable means, e.g. by a rear shutter mask (not shown), so that the movable contact 18b is forced upwards into operative contact with the upper stationary contact 180.

The power source switches 20 and 21 are actuated by a suitable'button (not shown), so that during each shooting operation, a movable contact 20b is pressed against a stationary contact 200 while separating the switch 21 from the contact. A numeral 22 represents a change over switch between continuous shooting mode of operation and single-frame shooting mode of operation. FIGS. 1, 8, and I1 illustrate the electric circuit of the takeup device of the present invention, in the state having complete its taking up operation. The counter switch 23 opens its circuit through its contacts upon completion ofexposing all the frames in a roll of film.

FIG. 3 shows the angular positions of the actuating shaft 13 and the cylindrical body 6d when the actuating shaft 13 is axially moved to its rightward position, as depicted in FIG. 6, in the aforesaid manner. At the illustrated angular positions, the low portion 6!) of the solid cam 9 engages the first arm 10a of the switch actuating lever (see FIG. 12), and the second arm 10b of the switch-actuating lever ,10 engaging the head cam plate 13a forces the actuating shaft 13 to its rightward position. A tail end 13c of the plate cam 13b engages the outer peripheral surface of the cylindrical member 6d, so as to prevent the actuating shaft 13, the head cam plate 13a, and the plate cam 13b from rotating by the elasticity of the spring 15. However, when the cylindrical member 6d is rotated counterclockwise by the engagement of its internal gear 6 with the planet gear 5 and its projection 6c comes into operative engagement with the plate cam 13b, the actuating shaft 13 is forced to rotate clockwise against the elasticity of the spring 15, so that a notch 13d is aligned with the second arm 10b of the switch-actuating lever 10, as shown in FIG. 4. At this mo- V ment, the actuating shaft 13 is forced to move Ieftwards, as seen in FIG 7, so as to receive the second arm 10b in the notch 13d of the head cam plate 130. Thus, the movable contact 16b of the second switch 16 moves away from the stationary contact 16c and comes into contact with the other contact 16a, as shown in FIG. 7. FIG. 5 shows the angular position of the actuating shaft 13 in the state as held by the engagement of the second arm 10b of the actuator lever 10 in the notch 13d of the head cam plate 130 of the actuating shaft 13.

FIGS. 8, 9, and 10 are circuit diagrams, illustrating the operative positions of the switches 12, 16, 18, 20, 21, and 22 in the motor-driven takeup device of the present invention.

FIG. 11 illustrates another electric circuit usable in the motor-driven takeup device of the present invention, in which a suitable control circuit, e.g. a radio-control circuit, is inserted between an electric power source 24 and a driving motor 1. In the circuit of FIG. 11, a portion A represents a driving means, a portion B represents an intermediate switching means, e.g. a radio-control circuit, and a portion C represents a groups of switches for the power source. Switches X, 21Y, 22Z, or switches 20X, ZI'Y, 22'2, which correspond to the switches 20, 21, 22 of the preceding embodiment facilitate the adoption of a remote control system.

In the case of the continuously shooting mode of operation, the switch 22 is closed as seen in FIG. 1 and the contact 20b of the switch 20 is switched to contact with the contact 200 and the switch 21 is departed from its contact by the operation button. Then the driving motor 1 rotates a driving gear 2, from its position at the end of a preceding takeup operation (In this case, the load on the cylindrical member 6 is smaller than that on the film takeup shaft 140), in a counterclockwise direction, as seen from the line III-III of FIG. 1, so as to rotate a sun gear 4 clockwise through a transmission gear 3. Accordingly, an internal gear 6 is rotated counterclockwise through a planet gear 5. Thereby, the first arm 10a of aswitch actuating lever 10 moves from a high portion 6a to a low portion 6b of the solid cam 9 formed at the left-hand end of the cylindrical member 6d, in response to the rotation of the internal gear 6. Hence, the switch-actuating lever 10 rotates counterclockwise, as seen in FIG. 1, due to the elasticity of a spring 11, so that a second arm 10b of the switch-actuating lever 10 forces an actuating shaft 13 rightwards to the position as shown in FIG. 6. At the same time, a release lever 17 is rotated by the engagement of its tail end 17b with a plate cam 13b secured to the actuating shaft 13, so that the shutter (not shown) is actuated. Simultaneously, a first switch 12 and a second switch 16 are switched over so as to bring their movable contacts 12b and 16b to right-hand side stationary contacts 120 and 160, respectively. At this moment the movable contact 18b of a third switch 18 is kept in engagement with its lower stationary contact 18a. As a result, a breaking circuit is completed, which traces from one terminal of the driving motor 1, through switch contact 18a, 18b, E60, 16b, 12c, and 12b, and back to the opposite terminal of the motor I, as depicted in FIG. 9. Thus, the driving motor 1 is braked and stops suddenly. I

Upon completion of each shooting, a switch actuator 19 is rotated clockwise, as seen in FIG. 1, by a suitable means (not shown), so as cause the movable contact 18b of the third switch 18 to come into operative engagement with its upper stationary contact 18c. Thereby, a circuit is completed, which traces from one terminal of an electric power source 24, through a shunt switch 22, the switch contacts 180, 18b, 16c, 16b, 12c, 12b, and the driving motor 1, and back to the opposite'terminal of the power source 24, as shown in FIG. 10.

As a result, the rotation of the driving motor 1 is resumed. Immediately after the resumption of the rotation of the driving motor 1, a projection 6c secured to the outer peripheral surface of the cylindrical member 6d actuates the tail end of the plate cam 13b secured to the actuating shaft 13, so as to allow rotation of the actuating shaft 13 counterclockwise, as seen in FIG. 3, against the spring 15. Thus, the second arm 10b of the switch actuating lever 10 fits in a notch 13d bored on the headplate cam 13a secured to the actuating shaft 13 by the elasticity of the spring 15, as shown in FIGS. 4 and 7. As a result, the second switch 16 is switched over, and its movable contact 16b comes into operative engagement with its lefthand side contact 16a. Consequently, it will be understandable that the contact 16b is switched to contact with the contact 16a before the contact 18b is switched to contact with the contact 18a, so that the circuit leading to the power source is maintained in the closed state.

It should be noted here that the aforesaid switch-over of the second switch 16, as depicted in FIGS. 4 and 7 is very important in the takeup device of the present invention. With known motor-driven takeup devices, upon completion of each taking up operation, the driving motor is stopped immediately by opening a switch circuit similar to the circuit between the contacts 18b and 18c in the third switch 18 of the device of the present invention. The procedure for stopping the driving motor 1 subsequent to the opening of the circuit between the contacts 18b and 180, in response to the completion of the taking up operation, has been described in the foregoing refer ring to FIGS. 6 and 9. A procedure similar to the aforesaid procedure to stop the driving motor 1 takes place in known motor-driven takeup devices upon completion of each taking up operation. On the other hand, in the case of continuous mode of operation in the motor-driven takeup device of the present invention, the circuit of the third switch 18 is bypassed by the aforesaid switch-over of the second switch 16, so that the driving motor 1 does not stop at the end of each film taking up operation despite the interruption of the circuit through the switch contacts 18b and 180. In short, the bypass circuit through the contacts 16b and 16a in the second switch 16 constitute an important feature of the present invention.

As said in the above, in case of long continuous exposure in the known devices, the motor tends to stop immediately after removing a finger from the operating button during such exposure, despite the fact that the camera should remain in the sate as holding the film taken up. According to the present invention, even if an operator removes his finger from the operating button during the film exposure, since a circuit, which traces from one terminal of the battery 24, through the switch 21, switch contacts 180, 1812, 16c, 16b, 12c and 12b, and the motor 1, and back to the opposite terminal of the battery, is formed by the actuation of the switch actuator 19 by which the contacts 18c and 18b are connected each other upon completion of each shooting operation, the motor 1 is started to rotate and then a circuit, which traces from one terminal of the power source 24, through the bypass switch 22, switch contacts 16a, 16b, 12c, 12b, and the driving motor 1, and back to the opposite terminal of the power source 24, is completed, and thus, the driving motor 1 continuous of rotating. Thereby, the film takeup shaft is driven first by the motor 1 to take up a film. Upon completion of taking up one frame of the film, the film takeup shaft 14a is locked by a suitable means (not shown), and the mechanical load on the film-winding shaft 14a from the driving motor 1 increases so much that the cylindrical member 6d is forced to rotate by the torque from the driving motor 1 Accordingly, the first arm 10a of the switchactuating lever 10 moves from the low portion 6b to the high portion 6a of the solid cam 9 formed at the left-hand end of the cylindrical member 6d, as seen in FlG. l. The switch-actuating lever 10 rotates clockwise, against the elasticity of the spring 11, in response to such movement of its first arm 100. As a result, the movable contact 1211 of the first switch 12 moves away from its right-hand side stationary contact 12c to the left-hand side stationary contact 12a. Thus, a circuit is completed, which traces from one terminal of the power source 24, through the switch terminals 20c, 20b (to be pressed against the switch contact 20c during shooting by a button, as described hereinbefore), 12a, HI), and the driving motor 1, and back to the opposite terminal of the power source 24. At the same time, the actuating shaft 13 is moved to leftwards by means of the spring 15 in response to the counterclockwise rotation of the switch-actuating lever 10. In this case, since the moving stroke of the lever 10 ismade larger than that of the actuating shaft 13, the first arm 10a of the lever 10 is departed from the notch 13d of the head cam plate 131:, and thus the actuating shaft 13 is revolved in counterclockwise direction in FIG. 3 so that it comes back to its original position as shown in FIGS/1 and 3. The driving motor 1 continues its rotation to complete a cycle for the next shooting mode of operation. When the operator removes his finger from the operating button (not shown), the switches and 21 return to the position as illustrated in FIG. 1, and thus the break circuit is completed, and the motor is stopped suddenly in the state of completion of taking up of the film.

The operation of the device of the present invention during the single-frame shooting mode of operation will now be described. To begin with the bypass switch 22 is opened. Therefore, in the case of the single-frame shooting mode of operation, the automatical feeding circuit as completed in the case of continuous shooting mode of operation is not completed, which circuit traces from one terminal of the power source 24, through the switch 22, the switch terminals 18c, 18b, [60, 16b, 120, 1217, and the driving motor 1, and back to the opposite terminal of the power source 24. A circuit is closed after the operator has removed his finger from the operation button, which circuit traces from one terminal of the power source 24, through the switch 21, the switch terminals 18c, 18b, 16c, 16b, 12c, 12b, and the motor 1, and back to the opposite terminal of the power source 24, and then the motor is started to rotate. Even if the operator has removed accidentally his finger from the operation button during the shutter operating, the terminal 18b will be contacted to the terminal 18c by the switch actuator 19 after exposuring, and thus the last said circuit is completed to rotate the motor 1. Therefore no trouble will occur by said accident. When the taking up operation is completed, the movable contact 12b of the first switch 12 moves away from its left-hand side stationary contact 12a to the right-hand side stationary contact 120, in the same manner as described in the foregoing referring to the continuous shooting mode of operation. Accordingly, an electric circuit is completed, which traces from one terminal of the driving motor 1, through switch contacts 20a, 2011, 12a, and 12b and back to the opposite terminal of the driving motor 1, as shown in FIG. 8, so that the driving motor 1 is short circuited and stops very quickly. Thus it will be understandable that according to the present invention, even if the operator remove his finger from the operation button during film exposing, the motor 1 is stopped after completion of taking up of the film in either case of the continuous shooting mode of operation or the single-frame shooting mode of operation. It is apparent to those skilled in the art that the similar singleframe shooting mode of operation can be fulfilled with the circuit of FIG. 11, which includes switches 20X, ZlY, ZZZ, as well as 20'X, 2] Y, 22Z, corresponding with the switches 20, 21, and 22 of the first embodiment of FIGS. 8 to 10. The embodiment of HG. ll can be operated either at the B portion, or the C portion thereof.

As described in the foregoing, according to the present invention, there is provided a motor-driven takeup device having a second switch 16 which can be operated separately without affecting other switches, by means of the engagement between the second arm 10b of a switch-actuating lever 10 with the notch 13d of an actuating shaft 13. The device of the invention also comprises a pair of braking circuits to brake a driving motor, which are completed upon completion of filmwinding operation and just prior tothe shutter operation, respectively, Withsuch braking circuits, the driving motor 1 can be stopped very quickly despite its high revolving speed, without dragging to the succeedingphase of operation, so as to carry out the high speed film-winding operation. Furthermore, in the winding device of the present invention, the use is made of a manual two contact switch 20 arranged in one of the two braking circuits and adapted to complete a braking circuit and a feeding circuit, a first two-contact switch 12 pivoted at the shutter releasing to complete the other braking circuit, a second two-contact switch 16 bypassing a third switch (18) only when a shutter release member is depressed by a finger for continuous shorting operation and otherwise connecting the power source 24 to the driving motor 1, a third two-contact switch 18 for actuating said other one of the two braking circuits after each shutter release operation while disconnecting said other braking circuit during shutter release operation for the purpose of connecting the power source 24 to the driving motor 1, and a switch 21 arranged in said feeding circuit and operated together with a manually operating switch 20. Thus, both the driving motor actuating circuit and the film driving mechanism are simplified. With the motordriven takeup device of the invention, any misoperation of the camera by a photographer does not cause any troubles in the mechanism of the device, and the device stops accurately and exactly upon completion of a film taking up operation immediately following the removal of a finger from the operating button. The outstanding features of the device of the present invention is in the simplification of the mechanical construction and electric circuitry, compactness of the construction, high speed operation, and others.

Although the present invention has been described with a certain degree of particularity, it is understood that the present disclosure has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.

We claim:

1. An electric winding device for a camera comprising a power transmission with a differential mechanism to selectively transmit the output power from a driving motor to a film takeup shaft and a first switch-actuating means, said differential mechanism including a cam means cooperating with said first switch-actuating means and said differential mechanism driving said film takeup shaft when the load on the film takeup shaft is smaller than a certain load preapplied to said cam means, while said differential mechanism driving said cam means to actuate said first switch-actuating means when said load on the film takeup shaft is larger than said certain load, first and second braking circuits respectively short circuiting the terminals of said driving motor and arranged in parallel with a feeding circuit for driving said motor, a manual two-contact changeover switch arranged in said first braking circuit and completing either the braking circuit or the feeding circuit by switching it manually, a first two-contact switch to be actuated by said first switch-actuating means together with each shutter release operation so as to connect said second braking circuit to said driving motor, a second two-contact switch completing the feeding circuit except when a shutter release member is depressed to close said second braking circuit, a third two-contact switch arranged in said second braking circuit and adapted to open the last said braking circuit through an actuator member upon completion of shutter release to complete the feeding circuit, said second two-contact switch being arranged in series with said third two-contact switch, a switch means arranged in said feeding circuit and manually operated together with said two-contact changeover switch, another switch means for selecting one of a continuously shooting mode operation and a single-frame shooting mode of operation, said other switch means is arranged in parallel with said switch means, and second switch-actuating means cooperating with said first switch-actuating means and adapted to actuate said second two-contact switch.

2. An electric winding device for a camera as described in claim 1, wherein said differential mechanism comprising a cylindrical body carried by a driving shaft and having an internal gear and the solid cam formed in one side of the body, said solid cam engaging the first switch-actuating means, a sun gear mounted rotatably on said driving shaft and driven by the motor through a gear train, a planed gear meshed with said internal gear and said sun gear and supported by said driving shaft so as to revolve together with it, whereby taking up of a film and charging and releasing of shutter can be automatically carried out depending on the magnitude of the load on the film takeup shaft.

shaft, and a head plate cam secured to the other end of said actuating shaft and having a notch engageable with the first switch-actuating means when said cylindrical body rotates said actuating shaft, which engagement of the first switch-actuating means with said notch provides a bypass circuit of the second two-contact switch so that the driving motor does not stop until the end of each taking up of the film despite the interruption of the circuit through the third two contact switch.

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