CA1264591A - Camera which can regulate the exposure area of a frame of film - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE:

A whole frame/half frame camera has a push bar extending outside the camera body to allow the activation of a regulating plate inside the camera body. When actuated, the plate moves in a fixed orbit to be positioned in one of two positions. In one position, the plate causes a view shield device to shield a portion of the view area on two sides of a viewfinder, and induces a pair of opaque movable blades to shield an exposure window also from two sides. In this position the plate also activates a clutch device for con-trolling a film advance wheel such that the wheel will rotate only a half cycle for each photograph taken, so reducing the length of film wound to one half of the length that is wound for a whole frame photograph.

Description

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The present invention relates to a camera which can regulate the exposure area of a frame of film.

Nowadays, cameras can be divided into two types according to how the film is used. One type is known as a "whole frame"
camera and the other type as a "half frame" camera. Thus, a camera loaded with a 36 exposure roll of ~ilm can take 36 pictures, if it is a "whole frame" camera, and 72 pictures, if it is a "half frame" camera.

The reason is that on pressing the shutter release button of a whole frame camera~ a whole frame of film is exposed to light, while for the "half frarne" camera, only one half of a frame of film is exposed. As a result, a "half frame"
camera can take twice many pictures as a "whole frame"
camera.

Of course, a "whole frame" camera can take wider and cleaner pictures as its exposure area is a "whole frame". ~lowever, when the object to be photographed is -too small or too far away, there are always some areas on either side of the frame of film which are superfluous and therefore some parts of the film are wasted. In -this latter situation, the ideal and most economical way to proceed is to take the pictures with a "half frame" camera.

Furthermore, when taking pictures, it is a common experience to discover that when the roll of film is nearly used up, it is desired to take several more pictures for which the remaining film is insufficient. In such a predicament, changing a "whole frame" camera to a "half frame" camera, would allow the taking of all the pictures desired.

There are several U.S.A. patents disclosing devices which 4 ~

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adjust exposure area or which alter what is photographed.
For instance, the device disclosed in the U.S. Patent No.

2,247,10~ adjusts the exposure area of a film by using a roll and a string to pull a screen to move towards the film horizontally so that the area of exposure can be appropriately shielded. This davice is very complicated, cannot regulate the length of film which has been wound, and is not easily operated.

The device disclosed in U.S. patent No. 2,295,801, uses a slide to adjust a mask plate to shield the dimensions of the viewfinder and to adjust the winding length of the film simultaneously by means of a gear set. Furthermore, separate operation makes the opening rotate 90 degrees to change the exposure area.

In the device disclosed in U.S. patent No. 2,522,387, the body of the camera can move from two end sides towards the centre to change the width of the camera body such that the exposure area and the viewfinder dimensions are adjusted.

All the devices described above possess a complicated structure and cannot be manufactured easily.

It is therefore an object of the present invention to provide a device which can change dimensions quickly, and which can be operated easily while being not easily breakable and having a simple body structure. The forgoing objects are not provided by the prior devices discussed.

Another object of the present invention is to provide a camera having two frame sizes operating by movement of a special device which actuates the view shield to shield a portion of the view area on two sides of the view~inder such , - 2 -, .

that the effective view width of the viewfinder is reduced to one half of its original size. Furthermore, this object envisages two opaque, movable blades shield the exposure window on the two sides such that the exposure width is also reduced to one half of its original size. Meanwhile, it is intended that the length of film to be wound on by each turn of the advance wheel be reduced to one half of the original length.

In meeting these and other objects the present invention provides a camera which can regulate the exposure area of a frame of film. The camera comprises:
(a~ a body;
tb) a film advance wheel for turning the film take-up spool around and for returning a shutter striking plate to its original position;
(c) a regulating plate;
(d~ a view shield device arranged to be actuated by the regulating plate and movable between a first position in which it is substantially clear of the viewEinder and a second position in which it is effective to shield the viewfinder to reduce the viewing area to approximately half the total width thereof;
(e) means for guiding movement of the regulating plate;
(f) at least two opaque movable blades arranged to be driven by the regulating plate to shield an exposure window of the camera from the sides of the window such that the width of the exposure window is reduced to approximately one half of the total width;
(g) a clutch device actuable by the regulating plate to control the film advance wheel to rotate . ~

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through one cycle or one half on each operation of the shutter mechanism of the camera;
(h) an operating member accessible from outside the camera .

This operating member is arranged to cause the regulating member to move between two positions. The regulating member is so arranged, that when moved from its first to its second position, it moves the view shield device to the second position and moves the opaque movable blades to shield half of the width of the exposure window and also moves control means for the film advance wheel so that the wheel can rotate through only one half cycle after each shutter operationn In this way, the length of the film advanced is reduced to one half of the normal length advanced.

The operating member is also arranged in such a way that when it is moved from the second position back to the first position, it moves the view shield device to the first position, and moves the opaque movable blades to a position ` in which they no longer obstruct the exposure window and also moves the control means for the film advance wheel so that the wheel can rotate through one full cycle after each shutter operation. By this means the length of film advanced corresponds to a full frame of the exposure window.

All the above aspects add together to allow the photographer to take a general "whole frame" picture or a "half frame"
picture according to need all with the same camera.
The invention is hereafter described in detail with reference to the accompanying drawings given only as non-limiting examples of embodiments of the present invention.
In the drawings:

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Fig. 1 is a top sectional view of one embodimen-t -taken along the line 1-1 of Fig. 2 and showing the changing device for the exposure window width;

Fig. 2 is a front view and partial sectional view taken along the line 2-2 of Fig. l;

Fig. 3 is a rear view of the Fig. 2 to show the position of the regulating plate;

Fig. 4 is a top view taken along the line 4-4 of Fig. 3;

Fig. 5 is a top view taken along the line 5-5 of Fig. 3 showing the length control of wound film;

Fig. 6 is a perspective view showing the corresponding positions of the main components of this invention;

Fig. 7 is an exploded, perspective view of a second embodiment of the invention;

~ig. 8 is a partial top view of the second embodiment showing that the reyulating pla-te can drive the opaque movable blade;

Fig~ 9 is a partial front view of the second embodiment to show another view shielding device for shielding the viewfinder;

Fig. 10 is a partial top view of the second embodiment showing that the regulating plate can control the rotation range of the film advance wheel;

Fig. 11 is a sectional view taken along the line 11-11 of ,;, - 5 -"

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F'ig. 10;

Fig. 1~ is a partial sectional, front view of a third embodiment showing how the regulating plate controls the film advance wheel;

Fig. 13 is another front view similar to Fig. 12 but showing another operation;

Fig. 14 is a front sectional view similar to Fig. 12 but showing additional components;

Fig. 15 is a front view of a fourth embodiment showing how the regulating plate controls the film advance wheel, Fig. 16 is a partial side view of Fig. 15;

Fig. t7 is a side view of a fifth embodiment showing how the regulating plate controls the film advance wheel;

Fig. 18 is a partial sectional view taken along the line 18-18 of Fig. 17;

Fig. l9 is a partial sectional view ta]cen along the line l9-19 of Fig. 17; and Fig. 20 is a perspective view of a sixth embodlment.

According to one embodiment of the invention, the view shield device comprises a viewfinder eyepiece cover (thewidth of the view shield device is one half of the width of the viewfinder) movable with the regulating plate to overlap the viewfinder when the said regulating plate is moved to its second position.

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12~i~S91 In another embodiment of the invention, the view shield device comprises a pair of indicating pointers which are actuable by the regulating plate and can be moved from the sides of the viewfinder to cover the side areas of the view~inder, when the regulating plate is moved to its second position.

As a further alternative, the view shield device may comprise an indicating device which is actuable by the regulating plate and is pivotally movable to cover the side areas of the viewfinder, when the reyulating plate is mov~d to its second position.

The clutch device may comprisee at least one inclined plate which is on the regulating plate and is engageable with means for regulating the elevation of a locating hook, and therefore the film advance wheel may be provided with two projections of different height: the locating hook effective to block only one of the projections in the first position of the regulating plate to permit one complete revolution of the film advance wheel, or the said locating hook to block both of the proiections in the second position of the regulating plate to permit only half a revolution of said film advance wheel.
Alternatively, the clutch device may comprise two overlapping clutch plates mounted on a shutter striking plate and the film advance wheel may be provided with two projections of different height: said clutch plates being movable by the regulating plate to one position so that only one of the projections is blocked by the clutch plates so as to permit one complete revolution of the film advance wheel, and in the other position both of the projections are blocked by the clutch plates so as to permit only half a " "

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revolution of the said film advance wheel.

Preferably, the projections on the fllm advance wheel comprise pins of different height spaced apart by 180 degrees from each other and loc~ted at substantially the same radial distance from the axis of the wheel.

According to another embodiment of the invention, the clutch device comprises an auxiliary drive wheel which is engageable with the film advance wheel and which is coaxially arranged with respect thereto, the regulating plate having an inclined face which is engageable with the auxiliary drive wheel to raise or lower said wheel and the auxiliary drive wheel having a projection which in the lower position of said wheel is engageable with blocking means to restrict rotation of the film advance wheel. The projection on the auxiliary drive wheel may comprise an auxiliary drive rod which extends through a bore in the film advance wheel provided with a main drive rod spaced from the auxiliary drive rod by 180 degrees, the rods being located at substantially the same radial distance from the axis of said film advance wheel. Alternatively, the projection on the auxi.liary drive wheel may comprise a drive camO

According to a further embodiment of the invention, the clutch device comprises a cam having two cam lobes mounted on the film advance wheel, one cam lobe being engageable with a projection in both positions of the regulating plate and the other cam lobe being engageable with a projection on only the second position of the regulating plate. The regulating plate may be provided with an inclined face which is engageable with a lever and which is effective, when the regulating lever is moved to its second position, to move said lever into a position in which it is engageable with ~26~g~

both of said cam lobes.

According to yet another embodiment oE the invention, the clutch device comprises a brake plate engageable with a drive cam mounted on the film advance wheel, one end of said brake plate being engageable by the drive cam and the other end being engageable in an opening in a press plate, the brake plate being movable, in response to movement of the regulating plate, between a first position in which it 10 permits one complete revolution of the film advance wheel for full frame photography and a second position in which it permits only one half revolution of the film advance wheel for half frame photography.

15 Referring to the drawings, the camera has a chamber for accommodating a film cartridge 101 from which a film 1~ can be pulled to pass an exposure window 12 of an exposure chamber 11 and be wound up by a film advance wheel 13.

20 In between the exposure window 12 and the lens 21, there are two opaque movable blades 121 which are easily pulled by the whirl spring 122 and open toward the lens 21. The heads (front ends) of these movable blades 121 are supported by respective push bars or rods 31. When the push bar or rod 25 31 moves towards the camera back cover 22, it pushes the opaque movable blades 121 to cover the two sides of the exposure window 12 (as shown by dotted lines in Fig. 1 and Fig. 2) so that the exposure width of the frame of film 10 will be less than one half of the original exposure width.
30 The push bar or rod 31 is set on a plate 33 which extends backwards, then bends 90 degrees to be vertical and is mounted on a convex rod 32. This convex rod 32 slides in a sloping elongated slot 41 of a regulating plate 40. This regulating plate 40 can be moved to the left or to the right ."'.. `~
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and its back edge has a positioning bulge 42 engageable with one of two notches 141 on the positioning plate 14 such that the regulating plate 40 moves along the positioning plate 14 until positioned at one of two fixed loca-tions.

As shown in Figs. 3, 4, and 6, a push bar or "operating member" 45 is mounted on the regulating plate 40 and extends to the outside of the camera body 20 such that the position of -the regulating plate 40 can be controlled by the push bar lQ 45 from outside the camera body by movement to the right or left. A pair of sloping cuneate plates 44 forming the left hand extremities (or "inclined ends") of regulating plate 40 are mounted under a reciprocating plate 501 such that this reciprocating plate 501 can be pushed to rise or fall. Each side of the reciprocating plate 501 carries a rod 502 which penetrates a plate 23 and then is mounted in a coil spring 503 to urge the plate 501 against the plates 44. A locating hook 50 is mounted at the lower end of one the rods 502 so that the locating hook 50 can move with the reciprocating plate 501.

The free end 504 of the locating hook 50 has one opening that is used Eor blocking a lower positioning pin 61 or an upper positioning pin 62. These two positioning pins, 61 and 62, subtend 180 degrees and have the same radius and are Eixed on the film advance wheel 60. The two pins 61 and 62 can push striking plate 70 to a position ready for striking.
The striking plate 70 has a pair of elongate slots 701 in which are located respective guide pins 22 so that the striking plate 70 can move along a fixed orbit.

As shown in Fig. 3, when the regulating plate 40 is pushed by push bar 45 to the right, the whole device is set for whole frame use. The active viewEinder eyepiece cover 46 is ,:, . .

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moved away from the viewfinder 24, so that the viewfinder 24 can be used for whole frame photography. The sloping cuneate plates 44 forming the inclined ends of the regulating plate 40 push the reciprocating plate 501 to cause locating hook 50 to rise such that the free end 504 of the locating hook 50 can block the upper positioning pin 62, but cannot block the lower positioning pin 61 because the lower positioning pin 61 can pass under the locating hook 50. Furthermore, the sloping elongate slot 41 of the regulating plate 40 does not push the convex rod 32 at this time to that the push bars 31 (attached to the convex rod 32) as shown in Fig. 1, will not shut the opaque movable blades 121 so that the exposure window 12 opens fully. The film advance wheel 60 thus can rotate one cycle each winding. During each rotation, the striking plate 70 is pushed to the position ready for striking the shutter. The film advance wheel rotates once as the shutter is struck once and the film advance wheel 60 will wind the film to the length required for whole frame photographin~.
If it is desired to change the camera of this invention for half frame photography, the push bar 45 is used to push the regulating plate 40 to move along the positioning plate 14 until the bulge 42 (or "positioning projection") of the 25 regulating plate 40 locks with a notch 141 of the positioning plate 14. In this position, the viewfinder eyepiece cover 46 will lie over the viewfinder 24. Since the width of viewfinder cover 46 is one half of the width of the viewfinder 24, the object viewed from the viewfinder 24 is reduced to one half of the whole frame use. At this stage, the sloping cuneate plate 44 of the regulating plate 40 leaves the bottom of the reciprocating plate 501 so that the reciprocating plate 501 is subject to the tension force of the compressed spring 503 and its own weight and, ~ :' 69~

therefore, drops so that the free end 504 of the locating hook 50 blocks either the upper positioning pin 62 or the lower positioning pin 61. Meanwhile, the sloping elon~ate slot 41 pushes the convex rod 32 which moves the plate 33 along a path in a direction which is perpendicular to the pulling direction of the film 10. Thus, the push bar 31 pushes the opaque movable blades 121 to shield the exposure window 12 from two sides of the exposure window 12 so that the width of the exposure window 12 is reduced to one half of the original width (of the whole frame). Since the locating hook 50 can block the upper positioning pin 62 and the lower positioning pin 61, when the shutter striklng plate 70 moves to a ready-to-strike position, the film takeup spool 13 rotates half a cycle but cannot continue winding the film 10. Therefore, the length of the film 10 to be wound is only half the length of that for whole frame use. As described previously, the width of the partly shielded viewfinder 24 is reduced to one half of the width in whole frame use, and the same is true for the exposure window 12. Thus, the camera according to this invention has become a half frame camera and can photograph double -the number of pictures as can whole frame camera.

As discussed, this invention provides a device which allows a camera to perform whole frame photography or half frame photography. Whenever the half frame camera is wanted, use in made of the push bar 45 outside the camera body 20 to push the regulating plate 40 inside the camera body 20.
This causes half the viewfinder eyepiece cover 46 to obscure the viewfinder 24, and also causes the two elements of the opa~ue movable blade 121 to move to either side of the exposure window 12 (located between the lense 21 and the film 10) and so shield the exposure window 12. In this way the width o~ the exposure windot 12 is reduced to one half ", ,; . ., -,, ~Z6a~

of the original. Meanwhile, the locating hook 50 is pushed down to block the upper positioning pin 61 such that the film advance wheel 60 can wind only one half -the length of tAe whole frame film as the striking plate 70 is prepared for striking the sh~tter. Thus, the viewfinder 24, the exposure window 12, and the wound film length are simulta-neously reduced to one half their values in the whole frame camera to allow half-frame photography.

~ second embodiment shown in Figures 7 to 11, achieves the same function as the foregoing example. In this second embodiment, it is shown that the regulating plate 40 can be designed to shift back and forth in order to make the camera become two sizes, which is an alternative to the first embodiment wherein the regulating plate 40 shifts horizontally to a~tuate the relevant components.

In the upper wall or the lower wall of both sides of the exposure chamber (or room) 11 are situated one pair of axle holes or bores 110 in which pivot the opaque movable blades 121. Moreover, the ~Ipper wall of the exposure chamber 11 carries a guide pin 111, a regulating plate 40, and a push bar (or "operating member") 45 extending outside the camera body. These latter are integrally interconnected and the plate 40 possesses Oll each side thereof one horizontal, lateral slot 401 and a spring rod 402. The spring rod is secured to one end of a tensioned sprin~ 124 to whose other end is attached an eccentric pin 123 located in the upper portion of each opaque movable blade 121. Furthermore, a projection 403 is provided on the far right hand side of this regulating plate 40, and an elongated slot 404 is provided on the left hand side. This elongated slot 404 receives the guide pin 111 to guide the regulating plate 40 when it is moving back and forth in the case where the lZ~ii4S9~

regulating plate 40 is mou~ted on the exposure chamber. A
slider 405 is connected behind the left hand side of the regulating plate 40. The portion of the slider 40 -that is close to the regulating plate 40 has a symmetrical contracted (frusto-conical) neck 406.

A plate 47 lies above the regulating plate 40. In the centre of this plate 47 is an opening 471 whose side has a support plate 473 to support the slide wall 451 at the lower end of the push bar 45. The two sides of the near end of the plate 47 have raised projections 472 which locate in the respective slots 701 of the striking plate 70 when the striking plate 70 is pLaced on top of the plate 47.
Therefore, the striking plate 70, owing to these raised projections 472 can slide horizontally with respect to the plate 47, within fixed limits defined by the slots 701. The left side of the far end of the plate 47 has pair of lugs 474 in the center of each of which is a pivot hole 475 to pivot two mirror image view shielding sticks 48. The lower ends 482 (i.e. below the pivot point) of each view shielding stick are pulled towards eachother (by springs 483) to clasp the neck 406 of the regulating plate 40. The upper end of each view shielding stick has an indicating pointer 481, or may carry any other equivalent appropriate indicating device, and as shown in Fig. 9, these pointers usually stay at the two sides of the viewfinder 24. Inside the viewfinder 24, there are two view boundary lines 241 and 242. The whole frame area boundary line 241 lies outside the half frame area boundary line 242. The half frame boundary's width is one half that of the whole frame area.
As the regulating plate 40 is moved towards the rear of the camera, the lower ends 482 of the view shielding sticks will clasp either side of the slider 405 at its wide portion such that the two indicating pointers 481 swing pivo-tally towards ~6~5~

eachother to ~ie in a position between the half frame boundary line 242 and the whole frame boundary line 241.
This lets the user understand that a half frame photograph is to be taken and that he or she must therefore consider the view inside the half frame boundary line 242.

The right side of the striking plate 70 has two guide rods 702, one spring rod 703, and one clutch plate 71 with two parallel elongate slots 711 in which the guide rods 702 of the striking plate 70 can slide thus allowing the clutch plate 71 to shift upon and relative to the striking plate 70O The right rear end of the projection 403 can push the clutch plate 71 to move on the striking plate 70. a spring 704~ attached to the spring rod 703 (located at the right rear end of the striking plate 70), urges the clutch plate 71 to move back to its original position. The lower edge of the film advance wheel 60 has a long rod 64 and a short rod 63 which define a 180 arc of fixed radius from the axis of the wheel 60. These two rods 64, 63 can be substituted by cams or by other equivalent components which provide the necessary motion and speciEic cyclic properties. When the clutch plate 71, as shown in Fig. 11, is pushed to the left by the projection 403 on the regula-ting plate 40 it shifts leftward to the position ready for halE frame photography.
At the same time the long rod 64 and the short rod 63 of the film advance wheel 60 push the striking plate 70 to shift the positioning arm 50 to the blocking position where it remains even after the striking plate 70 moves away. After taking a picture, the striking plate 70 comes back to its original position and the positioning arm S0 is therefore pushed away so that the film advance wheel 60 can rotate.
Thus, the film a~vance wheel 60 can only rotate a half cycle after each photograph. However, if the regulating plate 40 is moved rightward to its original position, only the long ., .

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rod 64 can push the striking plate 70, therefore, the film advance wheel 60 could rotate one complete cycle after each photograph.

According to the above description, as the regulating plate 40 shifts towards the rear of the camera on the axial line parallel to the lense 21, the pointers 481 of the view shielding sticks, designed for view shielding, can shield the sides of the viewfinder 24 and the opaque movable blades 21 also shield the two sides of the exposure window 12 to reduce the exposure window 12 to half width only.
Meanwhile, the clutch plate 71 is caused to shift, so that it achieves the position where the short rod 63 can push, and the positioning arm 50 can swing toward the left into a position which blocks the long rod 64 and the short rod 63 only after the striking plate 7Q has shifted to the left.
In this situation, the film advance wheel 60 only can rotate one half cycle after each photograph so that the film length to be wound for each photograph is one half of the film length to be wound for a whole frame photograph.

A third embodiment of this invention employs the regulating plate 40 to control the film advance wheel 60 as shown in Fig. 12 and Fig. 13.
In this example there is a flange 601 above the film advance wheel 60, and a main drive rod 602 is installed below the flange 601. A plug hole 603 is provided on the opposite side (separated by 180). The upper portion of the film advance wheel 60 penetrates an elongated slot 441 that lies centrally between the sloping cuneate plates 44 of the regulating plate ~0. Below the regulating plate 40, the wheel 60 plugs into an auxiliary drive wheel 65, below which there is an auxiliary drive rod 651 that penetrates the plug ~Z64~

hole 603 of the -film advance wheel 60 an~ extends through the whole by a length equivalent to the main drive rod 602 (Figure 12). The upper portion of the auxiliary drive wheel 65 is pushed continuously by the compressed spring 66. When the regulating plate 40 shifts to the right (i.e. from the position of Fig. 12 to the position of Fig. 13~, the auxiliary drive wheel 65 is forced (against the spring 66) by the sloping cuneate plates 44 to lift, so now only the main drive rod 602 is sufficiently proud o the flange 601 to push the striking plate 70 to move to the left ~there is no clutch plate 71 overlapping the striking plate 70 in this example). In this manner the positioning arm 50 driven by the striking plate 70 can only block the auxiliary drive rod 651 once per revolution o the wheel 60, thus, the film advance wheel 60 can rotate one cycle for each photograph.
however, when the regulating plate 40 shifts back to the left, the auxiliary drive rod 651 descends with the auxiliary drive wheel 65 to a position where it can push the striking plate 70. Now the positioning arm 50 can block the main drive rod 62 or the auxiliary drive rod 651 because the striking plate 70 has shifted to the left. Therefore, the film advance wheel 60 can only rotate one half cycle after each photograph. in this case, the regulating plate ~0 (similar to the firs-t example of this invention) has one sloping elongate slot 41. When the plate 40 shifts horizontally, it can drive the regulating plate 80 (indentical with the regulating plate 40 of the second example) back and forth by the aid of the convex rod 32.
This causes the opaque movable blades 121 to swing into the shield exposure window. In this case, the indicating device of the viewfinder 24 may use either the shielding method of the first example or the pointer method of the second example.

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In a fourth example of the invention shown in Fig. 15 and Fig. 1~, the re~ulating plate 40 is similar to the second example, and the film advance wheel 60 and the auxiliary drive wheel 65 are similar to the third example, but the compressing spring 66 is installed between the auxiliary drive wheel 65 and the film advance wheel 60. The upper surface of the auxiliary drive wheel 65 contacts a swing or pivoting lever 67, whose lower left side has a sloping face 671 and the le~thand end of the swing lever 67 has a vertically projecting rod 672. There is a pivot hole 673 at the center of the swing lever 67 to serve as a support point when assembled to the regulating pla-te 40. A push lever 407 extends from the regulating plate 40 and moves with it to the near end to push the rod 672 and to make the swing lever lS 67 swing to the right far end so that the sloping face 671 of the lower edge of the swing lever 67 compresses the auxiliary drive wheels 65 so that is descends with the auxiliary drive rod 651 to the position where it can push the striking plate 70. Thus, the film advance wheel 60, in this condition can only rotate a half cycle for each photograph 20 achieving the aim that the length of film to be wound is one half that of the original length. The working procedure is similar to the third example.

Fig. 17 to Fig. 19 show the structure of a fifth example of this invention. The regulating plate 40 of this example is similar to the second example, but the side below the push bar 45 connects with a compress plate 451 which possesses a sloping face and two different elevated faces. The right side of the striking plate 70 has a pair of lugs 705 about which pivot a swing lever 706 which is subject to an upward pulling force to bring the lever into contact with the compress plate 451. A two lobed cam 68 is installed above the film advance wheel 60 so that the cam 68 imparts two ,~,,,~
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strokes for each cyclic ro-tation but one of the lobes has a cut away opening 681 in its upper portion such that when displaced, the cam 68 can impart only one stroke percycle.
The cam 68 shape is demonstrated clearly in Fig. 18 and Fig.
19. When the operating member or push bar 45 shifts to -the near (left) end, the compress plate 451 compressess the swing lever 706 to a lower level at the section line 19-19 in Fig. 17. At this level, both lobes of the cam 68 can push swing lever 706 to make the striking plate 70 move to the left and to make the positioning arm 50 enter the blocking position. In this blocking position, one lobe is held against the rod 682 below the cam 68, therefore, the film advance wheel 60 can only rotate half a cycle for each photograph. However, if the push bar 45 moves to the far i5 (right) end, the swing lever 70 swings upwards (due to the spring force) to the level of the opening 681 so that it only can block the cam lobe which does not have the opening.
Therefore, the film advance wheel 60 rotates one cycle for each photograph.
All the examples described above use the film advance wheel 60 to push the striking plate 70 to a position ready for striking the shutter, however, a sixth example in Fig. 20 shows that the drive structure installed at the film advance wheel 60 is either a rod or a cam that changes the way the striking plate 70 is activated, from pushing to pulling. As shown in Fig. 20, there is a main drive cam 604 on the film advance wheel 60, whose function is equivalent to the main drive rod of the previous example. An auxiliary drive cam

3~ 691 is connected with elevating ring 692, which can lift or descend freely on the film advance wheel 60 when th`e auxiliary drive cam 691 is pushed by the sloping face of the regulating plate 40.

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A brake plate 81 has at one end a perpendicularly raised face 811 and is located within the radius of the action range of the drive cam 604. The centre of the brake plate is a long slot 312 pivoted about a pin 82 such that the brake plate 81 can rotate and can slide back and forth within a fixed travel orbit. The other end of the brake plate 81 is split into a blocking foot 813 and a support foot 814. This support foot 814 is continuously subject to the tension force of a spring 83 and rests against the side of a press plate 85 which has an openin~ 852 at its waist.
Therefore, when the press plate 85 is pressed, its lower end can push the shutter shield plate to move so that the film is exposed. Meanwhile, the bulge 851 at the side of the press plate 85 can push the brake plate 81 and make it shift 1~ forward slightly so that the raised face 811 at the front end of the brake plate 81 is no longer able to block cam 604 or 691 and the film advance wheel can therefore rotate counterclockwise due to the external force. At this moment, the brake plate 31 is pulled by the spring 83 and thus drawn back while swinging slightly towards the right to let the blocking foot 813 enter the safety opening 852 in the press plate 85. 'rhe press plate 85 cannot now be pressed further until one of the cams 604 and 691 can touch the bulge 851 of the brake plate 81 thereby pulling it forward to make the blocking foot 813 leave the opening 852 of the press plate 85, and finally return to its original position. Since the installation positions of cam 604 and cam 691 define a 180 degree arc, photography can proceed as the ~ilm advance wheel is controlled by the regulating plate 40 to rotate only half cycle.

In all the examples described above, when the striking plate 70 is pushed each time to the position ready for striking the shutter, whether the film advance wheel rotates a full ~Z6~

cycle or half cycle, the clutch device for the interaction between the striking plate 70 and the film advance wheel, whether it be a rod, cam, or equivalent device, always possesses ~n equivalent functional motion with a specific cyclic propert,v, they are regarded to be the characteristics of this inven-tion.

Based on all the examples, it can be understood that the regulating plate 40 of this invention actuates the view shield device, shields the portion of the view area from the two sides of the viewfinder, drives the opaque movable blades to swing to shield the exposure window from two sides, and actuates a clutch device to control the rotation range of the film advance wheel such that these devices according to this invention provide a camera which has two modes of operation, one for whole frame and the other for half frame photography and the modes can be quickly switched.

Claims (16)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A camera which can regulate the exposure area of a frame of film comprising:
(a) a body;
(b) a film advance wheel for turning the film take-up spool around and for returning a shutter striking plate to its original position;
(c) a regulating plate;
(d) a view shield device arranged to be actuated by the regulating plate and movable between a first position in which it is substantially clear of the viewfinder and a second position in which it is effective to shield the viewfinder to reduce the viewing area to approximately half the total width thereof;
(e) means for guiding movement of the regulating plate;
(f) at least two opaque movable blades arranged to be driven by the regulating plate to shield an exposure window of the camera from the sides of the window such that the width of the exposure window is reduced to approximately one half of the total width;
(g) a clutch device actuable by the regulating plate to control the film advance wheel to rotate through one cycle or one half on each operation of the shutter mechanism of the camera;
(h) an operating member accessible from outside the camera, said operating member being arranged to move the regulating member between two positions and the regulating member being arranged, when being moved from a first to a second position, to move the view shield device to the second position, to move the opaque movable blades to shield half of the width of the exposure window and to move control means for the film advance wheel so that said wheel can rotate through only one half cycle after each shutter operation such that the length of the film advanced is reduced to one half of the normal length advanced; when being moved from the second position back to the first position, to move the view shield device to the first position, to move the opaque movable blades to a position in which they no longer obstruct the exposure window and to move said control means for the film advance wheel so that said wheel can rotate through one full cycle after each shutter operation so that the length of film advanced corresponds to a full frame of the exposure window.

2. A camera according to claim 1, wherein said view shield device comprises a viewfinder eyepiece cover whose width is one half of the width of the viewfinder and which is movable with the regulating plate to overlap the viewfinder when the said regulating plate is moved to its second position.

3. A camera according to claim 1, wherein said view shield device comprises a pair of indicating pointers which are actuable by the regulating plate and can be moved from the sides of the viewfinder to cover the side areas of the viewfinder when the regulating plate is moved to its second position.

4. A camera according to claim 1, wherein said view shield device comprises an indicating device which is actuable by the regulating plate and is pivotally movable to cover the side areas of the viewfinder when the regulating plate is moved to its second position.

5. A camera according to claim 1, wherein said clutch device comprising at least one inclined plate on the regulating plate and said inclined plate is engageable with means for regulating the elevation of a locatiing hook and wherein the film advance wheel is provided with two projections of different height, the locating hook being effective to block either only one of the projections in the first position of the regulating plate to permit one complete revolution of the film advance wheel, or to block both of the projections in the second position of the regulating plate to permit only half a revolution of said film advance wheel.

6. A camera according to claim 1, wherein said clutch device comprises two overlapping clutch plates mounted on a shutter striking plate and wherein the film advance wheel is provided with two projections of different height, said clutch plates being movable by the regulating plate so that in one position only one of the projections is blocked by the clutch plates so as to permit one complete revolution of the film advance wheel and in the other position both of the projections are blocked by the clutch plates so as to permit only half a revolution of the said film advance wheel.

7. A camera according to claim 2, 3 or 4, wherein said clutch device comprises two overlapping clutch plates mounted on a shutter striking plate and wherein the film advance wheel is provided with two projections of different height, said clutch plates being movable by the regulating plate so that in one position only one of the projections is blocked by the clutch plates so as to permit one complete revolution of the film advance wheel and in the other posi-tion both of the projections are blocked by the clutch plates so as to permit only half a revolution of the said film advance wheel.

8. A camera according to claim 6, wherein the projections on the film advance wheel comprise pins of different height spaced apart by 180 degrees from each other and located at substantially the same radical distance from the axis of the wheel.

9. A camera according to claim 1, wherein said clutch device comprises an auxiliary drive wheel which is engageable with the film advance wheel and which is coaxially arranged with respect thereto, the regulating plate having an inclined face which is engageable with the auxiliary drive wheel to raise or lower said wheel and the auxiliary drive wheel having a projection which in the lower position of said wheel is engageable with blocking means to restrict rotation of the film advance wheel.

10. A camera according to claim 2, 3 or 4, wherein said clutch device comprises an auxiliary drive wheel which is engageable with the film advance wheel and which is coaxial-ly arranged with respect thereto, the regulating plate having an inclined face which is engageable with the auxiliary drive wheel to raise or lower said wheel and the auxiliary drive wheel having a projection which in the lower position of said wheel is engageable with blocking means to restrict rotation of the film advance wheel.

11. A camera according to claim 9, wherein the projection on the auxiliary drive wheel comprises an auxiliary drive rod which extends through a bore in the film advance wheel and wherein the film advance wheel is provided with a main drive rod spaced from the auxiliary drive rod by 180°, the rods being located at substantially the same radial distance from the axis of said film advance wheel.

12. A camera according to claim 9, wherein the projection on the auxiliary drive wheel comprises a drive cam.

13. A camera according to claim 1, wherein said clutch device comprises a cam having two cam lobes mounted on the film advance wheel, one cam lobe being engageable with a projection in both positions of the regulating plate and the other cam lobe being engageable with a projection in only the second position of the regulating plate.

14. A camera according to claim 2, 3 or 4, wherein said clutch device comprises a cam having two cam lobes mounted on the film advance wheel, one cam lobe being engageable with a projection in both positions of the regulating plate and the other cam lobe being engageable with a projection in only the second position of the regulating plate.

15. A camera according to claim 13, wherein the regulating plate is provided with an inclined face which is engageable with a lever and which is effective, when the regulating plate is moved to its second position, to move said lever into a position in which it is engageable with both of said cam lobes.

16. A camera according to any one of claims 1 to 3, wherein said clutch device comprises a brake plate engageable by a drive cam mounted on the film advance wheel, one end of the brake plate being engageable by the drive cam and the other end being engageable in an opening in a press plate, the brake plate being movable, in response to movement of the regulating plate, between a first position in which it permits one complete revolution of the film advance wheel for full frame photography and a second position in which it permits only one half revolution of the film advance wheel for half frame photography.