US2596671A - Camera shutter, including adjustable flash synchronizing means - Google Patents

Description

May 13, 1952 c, c, R T 2,596,671

CAMERA SHUTTER, INCLUDING ADJUSTABLE FLASH SYNCHRONIZING MEANS Filed Sept. '7, 1949 3 Sheets-Sheet l O 46' 1012/4/6/820222426 MILL/SECONDS 9 l3 l5 l7 l9 CARL C. FUERST INVENTOR amm 011a C- C. FUERST May 13, 1952 CAMERA SHUTTER INCLUIiING ADJUSTABLE FLASH SYNCHRONIZING MEANS 3 Sheets-Sheet 2 Filed Sept. 7, 1949 CARL C. FUERST INVENTOR away/ BY TTORNE S C- C. FUERST May 13, 1952 CAMERA SHUTTER, INCLUDING ADJUSTABLE FLASH SYNCHRONIZING MEANS Filed Sept. 7, 1949 5 Sheets-Sheet 3 CARL C. FUERST Patented May 13, 1952 N lTED is TATiE S PAT E NT F etc-E 2,596,671 CAMERA-SHUTTER, INCLUDING "ADJUST- ""'FI2ASH SYNCHRO NIZING MEANS "Carl C. Fuerst, Rochester, N. Y.,jassignor toEastman Kodak Company,- Rochester, N. -Y a cor- .vporation of NeW'Jer'sey AiipliatidNSBflfehtber 7, 1949, SeiiaI No. 114,375

.The 1 present invention relates to a flashlight synchronizing mechanism built into a ;photo graphic shutter, and. particularly to a synchronizin'g mechanism of this type in which the time delay between closing of "the lamp circuit and opening of the shutter is automatically adjusted to givethe best "possible light and speed combination for any-speed setting of the shutter.

Conventional non-repetitive fiashlamps are available inseveral types, the types :generally being distinguished'by the burning characteristics of the lamps. So far as the: present inventionis concerned, the only twotypes of larnps of interest are the type having substantially a 20-22 millisecond lag, and thetype having substantially-a millisecond -lag." The first-mentioned type of flashlamp produces a hi'ghe'r, peak illumination than the otherand has a light. curve extending over a much greater time duration, as will be set forthinmore detail hereinafter. "In otherwords, the lamps with a 22millis'e'cond lag come to peak illumination-more. gradually, having a wider peak, and 'die outmorefg'radually than lamps having a5 millisecond lag. Flashlamps; having a 2o 22 niillisecond "nag" "characteristic include :those on the market and designated as =type s #5, #11, #25, #f40, #42,jetc;; these: number designations being used by "different-lamp manufacturers.

Lamps havinga5 irnillis'econd tlag' c aracteristic includethe'SM flasmamp manufactured by GeneraLEIectric,Conipany. In o'r'derto' readily-identify these different types of fiashlainps according to their burning "characteristics" without referringv to manufacturers trade numbers, the AIT S, A! has setup s'pecificationsgi'ouping these different types o'f' fla shlamps i according to classes. According to AQS. "Specification 1"Z '-'52.43-l 944 all non repetitiveflashlamps having substantially a 20422 millis'econd la'g and the wide characteristic "light curve," are"desig'- nated as class M lamps; regardless "ofman'ufactui erdesignation. f'lhosej am s having subtantiallya 5 millisecond flag'! are designated as class 'Ff lamps. Accordingly, throughout; the present specification and claims, these two diffe'r entitypes er flashlamps will be referred'to as class M and class Fflamps; the"class"" M lamps includingfthose typeshaving substantially a "20 22 millisecond lag and relatively long light-emitting characteristics, while the class "F lamps include those types having a shorter substantially 5 millisecond lag and a relatively steep light curve, orone' of short duration.

"Conventional flash synchronizers cnthe= market'toda'y are only adjusted in accordance-with isfoiiim's. (01. 95-115) the lag" charact'eristic of ithe differentclasses of lamps adapted i to: be used withoutany consideration as to ishutters'peed to' be used. For instance, ifraisynchronizer is? to be" used only with class M" ifiashla'mps, it is usually adjusted $0 insure that the flash circuit iwillbe closed in proper ti'med' relation with operation of the shutter to insure the shutter being full-open when the" lampreaches itspeak of illumination. Such adjustments-are made 'to give th-issynchronization. at the: highest? shutter speed; of which the shutter is capable-because at these: high speeds the-shutter isopen forthe shortest time. How'- ever, when synchronizers: so adjusted-amused at the slower-shutter speeds, thatpor-tion of Lthe lightemitted during the -time that -the lamp; is coming upto peak is lost and the maximum light available is not used. With-class F? lamps', this loss ofuse oi light-at shutter speeds other; than that which the synchronizer is adjusted 'for is not so important because ofthe steepor nair'row nature of the light curves for these lamps. Those synchronizers which are adapted to Iaccon'imodate b oth: class -M' and class "-F lamps, as/wen as others, are usuallyadjusted betweenionly two or more positions, depending 'u cn "the'niifiiber of differentclass lamps to 'belffacconi'r'nodatd, each adjustment', being basedi'solely onlthe 'lag characteristic of the lamps without regard "to different shutter speeds which might be used. While some shutters "haying built-in synchroni'zers -adjustable by means f'of'a; scale itdafccjommodate bfoth classfM" and class F'ffiashlamps include intermediate points on I the fadjusting scale by which the operator can make anew ances-*for"shu'tter-"spe'd to -obtain="a'-'-better light and speed combinationthan the syn'ch'ronize-r is primarily aldjusitedior, such adiustments arezieit to the judgment of the operator and: require that he will be completely familiaruwith theiburning characteristics :of the classi ofilampsx to be used, along -with the opening characteristics of his shutter. Obviously; such adiustmentseare useful only to the-advanced amateurprprofessional who takes; the trouble "to; acquaint himself with vthe technicalities of shutter operation (and "lamp burning characteristics,."an'd, even "then, the adjustments hemight make are "only a proximate and will not give the best possible'lightfand speed combination.

One obj ectof thepte'serit invention is toprovide "a built-in flash *synchron-ize'r in" which the synchronizer is '-aut'omatica-lly adj listed ""by ad-- j-ustnient ofthe shutter speed control member to give the best possible light -and spe'ed' icombination for the class of fiasnlampi torlbemsed.

Another object is to provide a built-in flash synchronizer of the type set forth which is adapted to accommodate both class M and class F flashlamps, and in which adjustment of the synchronizer according to the shutter speed is accomplished when using only one, or when using both classes of flashlamps.

A further object is to provide a built-in flash synchronizer of the type set forth which is adjustable to accommodate both class M and class F flashlamps, but in which further adjustment of the synchronizer as to shutter speed is accomplished only when using class M lamps and the operative connection between the shutter speed control ring and the synchronizer for making this last-mentioned adjustment is automatically made and broken as the synchronizer is adjusted to and from, respectively, a position to accommodate M" class lamps.

And yet, another object is to provide in combination with a built-in flash synchronizer of the type described, including an electrical switch adapted to be operated by the shutter mechanism in proper timed relation with the opening of the shutter to produce the desired synchronization of light and shutter opening, and wherein the shutter is adjusted to vary the time of closing thereof in accordance with the class flashlamp used, an operative connection between the switch and speed control ring of the shutter by which the switch is further automatically adjusted in accordance with the selected shutter speed to give the best possible light and speed combination.

The novel features that I consider characteristic of my invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its methods of operation, together with additional objects and advantages thereof, will best be understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which Fig. l is a front elevational view of a complete photographic shutter having a built-in fiash synchronizer constructed in accordance with the present invention;

Fig. 2 is a graph showing the characteristic light curve for class F and class M flashlamps, and showing an operating curve of the disclosed shutter superposed on the class M light curve to bring out the purpose and advantages of the novel adjustment of the synchronizer in accordance with the shutter speed that I provide to obtain the best possible light and speed combination for any selected shutter speed;

Fig. 3 is a front view of the shutter with the cover plate removed and showing the operative connection between the flash switch and the speed control ring of the shutter;

Fig. 4 is a front view of the shutter with the speed control ring removed and showing the cam ring for adjusting the synchronizer to accommodate different classes of flashlamps;

Fig. 5 is an enlarged detail of that part of the shutter including the scale for adjusting the synchronizer to accommodate different classes of lamps; and

Fig. 6 is an enlarged view of the shutter with the cover plate and other parts removed to show the blade-operating mechanism of the shutter, along with the flash synchronizer particularly adapted for this type of shutter-operating mechanism and in combination with which the present invention is adapted for use.

Like reference characters refer to corresponding parts throughout the drawings.

Referring, first, to Fig. 2, the purpose and result of the present invention will be described in connection with the graphs of this iigure. Looking first at the characteristic light curve for class .I. iiashlamps, it will be seen that for the first two milliseconds after the circuit of this class of lamp is closed, there is no appreciable light emitted, and then the amount of light increases quite gradually until the peak of illumination is reached at between 20-22 milliseconos. The peak remains at its maximum for not more than two milliseconds and then the light gradually falls oif, taking more than 20 milliseconds to do so. In other words, this class of lamp is emitting some degree of light for over 40 milliseconds.

superposed on this light curve of the class M lamps is a curve showing the operating characteristics of a photographic shutter of the type in connection with which my invention is disclosed. This curve is characteristic of all between-the-lens type shutters and differs from most in that it includes a /800 speed, whereas most shutters only have a top speed of /200, or /400. The operating curve of the shutter is trapezoidal, the length of the top and bottom lines thereof varying with the speed of operation. As indicated by the slope of the upright lines of the shutter curve, this shutter in question takes approximately two milliseconds to reach a fullopen position after release and takes two milliseconds to close from a full-open position. The only exception to this is the /200 speed setting where an additional spring is added to the bladedriving mechanism and the opening and closing times drop to about one and one-half milliseconds each.

Looking at the shutter curve it will be noticed that when operated at a speed of /z5th second, the shutter is fully open for approximately 40 milliseconds, as indicated by the length of the top line bounded by the areas designated as brown. The full-open time of the shutter decreases as the speed increases until the /800 speed is reached at which the shutter is only fully open for a little over one millisecond, this area being designated as red on the shutter curve. The fullopen time of the shutter for the different speeds will vary with the speed as indicated on the curve; the /50 speed being designated as purple, the speed as yellow, the /200 speed as blue, and the /400 speed as green.

It will be understood that in order to function with the greatest efficiency, or to obtain the maximum available light at the top or /800 speed, the synchronizer must be adjusted so that the lamp will be at at its peak during the one and one-half milliseconds that the shutter is fully open at this speed. Taking into account the one and one-half millisecond opening time of the shutter at this speed, this means that the synchronizer must be adjusted to close the lamp circuit about 19 milliseconds before the shutter is tripped. This is the basis upon which most synchronizers are selectively adjusted by the operator, since their adjustment is generally only to accommodate for different classes of flashlamps and not for shutter speeds in addition to the class lamp.

If the synchronizer when adjusted by the operator to use class M lamps is factory set to synchronize properly at only the t or other top speed, it will be apparent from an inspection of Fig. 2 that if slower shutter speeds are used before the shutter is tripped, as is necessary to accommodate the /800 speed, and'the shutter is operated at a slower speed, then all or a part of the light emitted by the lamp, up until-1t reaches its peak, will be wasted, depending upon the shutter speed used because the shutter is not open during the time the lamp is reaching its peak. As a compromise, built-in synchronizers, adjustable to accommodate different classes of flashlamps, can be initially adjusted sothat when set for class M lamps they will close 'theswitch in timed relation to tripping of the shutter so as to bring the shutter to fullopen position at the highest speed slightly ahead of 1 the lamp reaching its peak. While this cuts down the maximum light available for operating at the highest shutter speed, it makes it possible for the slower speeds to get in more of the light underthe rising portion of the light curve. Even with such a compromise, the best possible light and speed combinations are not approached. Looking again at Fig. 2, it will be observed that when a th shutter speed is used with class M- lamps, the shutter is fully open so long that it could embrace almost the entire light output of the lamp if the delay time be tween switch operation and shutter tripping were reduced to '7 or 8 milliseconds. It also follows that in order to make use of the most available light at r, of a second shutter speed, the time delay should be 9-10 milliseconds; for a n speed a 11-12 millisecond delay, and so on up to a maximum delay of 19 milliseconds for a shutter speed. My present invention comprises a means whereby conventional built-in synchronizers will be automatically adjusted by the selective setting of the speed ring of the shutter to attain the desired time delay between closing of the lamp switch and tripping of the shutter, giving the best possible light-speed combination.

Looking at the light curve of the class F lamps, it will be seen that this class of lamps reaches its peak of ilumination rather quickly, about milliseconds, and the useful light area under the curve is only about 12 milliseconds in duration. Accordingly, for practically all shutter speeds, except the /3' if the shutter is tripped simultaneously with closing of the lamp switch, the shutter will be full-open to include the peak of illumination and will be open sufficiently long to make use of substantially all the available useful light. Because of the low light out ut of class "F lamps, as compared with class M lamps, class F lamps would not ordinarily be recommended for use with shutter speeds as high as ,430 or 4 Accordingly, I have found it desirable to correct the delay time of the synchronizer in accordance with the shutter speeds only when using class M lamps, although from the following description it will be obvious that the same adjustments could be provided and made available for class F" lamps, is desired.

For purposes of disclosing my present invention I have shown it in combination with a builtin synchronizer of the type fully described in my copending application Serial No. 737,351, filed March 26, 1947, now Patent No. 2,563,782, issued August 7, 1951, and in a, shutter having a bla.de-

6 operating mechanism of the type shown in my copending application Serial No. 728,528, filed February 14, 1947, now Patent No. 2,524,786, issued October 10, 1950. Inasmuch as the flash synchronizer and shutter blade operating mechanism are fully disclosed in my above-noted copending applications, only so much of the shutter blade operating mechanism and the flash synchronizer per se will be described herein as is necessary to point out the operation and purpose of the present invention. I

The shutter, of which a synchronizer modified in accordance with my present invention forms a part, may appear as shown in Fig. 1. As indicated, the shutter may consist of an annular casing i having a cover plate 2 surrounding a central exposure aperture3 and may contain for tensioning the operating spring. The cover plate includes a speed scale 8 with which an index P on the face of a knurled flange 5 of a speed control ring 30] see Fig. 3, cooperates. The cover plate is also provided with a diaphragm scale 9 with which a pointer P on the diaphragm adjusting ring, not shown, cooperates. The cover plate is also provided with a synchronizer adjusting means to make it possible for the operator to adjust the synchronizer for use with the different classes of conventional non-repetitive fiashlamps having characteristic lags and for use with repetitive type flash lam s having no lag, as exemplified by lamps of the gaseous discharge type.

As shown, this synchronizer adjusting means comprises a setting member 10 which is fastened to an adjusting cam in the shutter, as will be described, and which extends upwardly through and moves in an arcuate slot II in the shutter ter X, the synchronizer is adjusted for use with gaseous discharge type flashlamps having no lag,

but since this setting has nothing to do with the present invention, further description thereof and its functions will not be dealt with herein.

Essentially, the synchronizer, of which the present invention forms a part, comprises a se will be described herein sufficiently to point out the features of the synchronizer which are aifected by the present invention. It is pointed out, however, that since the present invention is not limited to use with a shutter mechanism of the type, described and said shutter mechanism is completely disclosed in, my above-noted copende ing application Serial No. 728,528, only so much. of

the mechanism per so will be disclosed herein as necessary to point out the operation of the flash synchronizer with which the present invention is combined.

As indicated in Figs. 4 and 6, the annular shutter casing may include an upstanding flange I5 extending around the periphery of the shutter; this flange having a slot I6 formed therein to permit movement of the setting lever and havin a slot II permitting movement of the trigger 6 for tripping the shutter mechanism. As clearly set forth in my above-noted copending application, and as indicated in Fig. 6, shutter blades I8 are of the symmetrical type, each blade being pivoted at I9 to the mechanism plate 20 and having an upstanding pin 2I extending through an elongated slot 22 in an oscillat-able blade ring 23. This blade ring directly carries an arm I which terminates in the setting member I and extends through the slot I 5 in the flange I5. A power spring 25 is connected at one end directly to the blade ring 23 by a pin 25 and is connected at the other end to a stud S carried by the shutter casing. Thus, the spring 25 acts directly on the blade ring 23 and it becomes tensioned when the setting member I is moved clockwise to the position shown in Figs. 3, 4 and 6.

As indicated in Fig. 6, the blade ring is held with the spring tensioned by means of a latch mechanism which consists of a first latch member 28 pivoted on the stud 29 attached to the mechanism plate 20. The latch 28 has a beveled end 3i and xtencls across the top of the shutter; and this latch member lying beneath a second latch member 32 also pivoted on stud 29. Latch 32 has a latch face 33 adapted to engage an outwardly projecting protuberance 34 on the setting lever i. This latch therefore holds the setting lever I and the blade ring 23 in their set position when the lug 34 moves up over the incline 35 of the second latch member as the handle I is moved to a set position. A downwardly extending flange 3S limits the unward movement of the second latch member 32 under impulse of its spring 31, but it also permits the second latch to move downwardly with respect to its Fig. 6 position and the first latch member 28.

The first latch 28 includes the beveled surface 3I, above referred to; which normally lies in contact with a beveled surface 38 on the shutter releasing member 39. This member may turn on a pivot 40 and includes a power spring I26 which by acting on pin i 53 fixed to and extending above member 39 tends to turn member 38 in a counterclockwise direction. When the beveled surfaces 3! and 38 engage, movement of member 33 is prevented because the engagement of these two surfaces is almost on dead center between the studs 40 and 29 on which the power-operated member 39 and the first latch member turn. However, the trigger 6 can start movement of the first latch member 28 and which movement may then be completed by the power-operated member 39 in a manner completely disclosed in m copending application Serial No. 737,351, above mentioned. It will suifice herein to say that there is a connection between the trigger 6 and latch member 28 by which depression of the trigger 6 causes latch member 28 to be depressed sufficiently to move the beveled surface 3| out of dead center relation with beveled surface 38, but by an insuflicient amount to actually trip the shutter. This further movement of latch member 28 is taken over by power-operated member 39 to actually release the shutter.

Coming now to the synchronizer with which the present invention is combined and which is fully disclosed in my noted copending application Serial No. 737,351, fastened to flange I5 of the shutter casing is a terminal I H to which a mating connector on a flashholder, not shown, may be connected. The flashholder will include a source of potential and a flashlamp respectively, shown diagrammatically in Fig. 4 as B" and L," and the terminal is such that one side of the flash circuit will be grounded to the shutter casing, while the other side will be connected to the center post I ll of the terminal which is insulated from the shutter casing and extends to the interior thereof.

The switch for synchronizing conventional nonrepetitive flashlamps having a lag" comprises a first contact which is the pin H0 carried by the shutter release member 39 and a second and adjustable contact H5 lying in the path of movement of the pin H6. The contact H5 is carried by insulating member 200 which is, in turn, carried by an arm I I3 pivoted on a stud I I4 fastened to the mechanism plate of the shutter. The arm H3 has an upturned lug 20I thereon which engages a cam surface I I2 on the synchronizer adjusting ring I00 which is oscillatably mounted in the shutter below the cover plate and speed control ring and which has the adjusting member I0 fastened thereto. Contact I I5 is electrically connected to the center post Ill of terminal III by an insulated conductor H8 lying adjacent the interior of the flange I5 of the shutter casing and a conductor strip 203 fixed at one end to the conductor H8 and at the other end to a pin 204 on the arm H5. Conductor strip 203 is made of a resilient metal and takes the form of a coil sprin so that it normally tends to pivot contact H5 in a counterclockwise direction and thus hold the lug 20I against the cam surface I I2.

Therefore, inasmuch as contact H5 is connected to one side of the flash circuit through conductor H8 and pin H6 is connected to the other side of the circuit by being grounded through the shutter casing, when pin I I 6 engages contact I I5 the flashlamp circuit will be closed to energize the lamp. Inasmuch as pin H6 is carried by the shutter releasing member 39, it can be made to engage contact I I5 at any desired time prior to the actual release of the shutter and in accordance with the lag" characteristics of the fiashlamp to be used. To obtain the desired delay between closing of the lamp circuit and the release of the shutter, there is provided a gearretarding mechanism including a flywheel 205 having a pinion 206 fixed thereto which, in turn, engages a gear segment 20! on the arcuate end of member 39. By adjusting the synchronizer ring [00 with the aid of member I0 and the scale I I, the position of contact I I5 relative to that of pin H6 on member 39 can be varied to obtain a synchronization between the peak of illumination of the fiashlamp and the full-open position of the shutter in accordance with class F" and class M" flashlamps. To allow the use of repetitive flashlamps of the gaseous discharge type which have no lag, this synchronizer may include a second switch in series or parallel with the first switch which closes the instant the shutter blades reach their full-open position; means being provided to render the first switch inoperative when the second switch is used and this being accomplished by adjusting synchronizer cam ring I00 to the "X" position on scale H. However, since this second switch does not enter into the present invention, it will not be described herein.

Coming now to the present invention, for reasons fully discussed above it is desirable to be able to adjust the firing time of the flash switch in accordance with the shutter speeds to be used, particularly when using class M lamps. To accomplish this, I attach a cam plate 300 directly to the speed control ring 30I of the shutter to move therewith. As is customary in all betweenthe-lens type shutters, the speeds are determined by placing a retard action on the spring-driven blade operating member. As shown in Fig. 3, this is done in the present shutter by pivoting a. double-ended lever302 on the mechanism plate so that one end 303 thereof can move into the path of pin 26 on the, blade-operating ring 23 and will have to be cammed out of the way by movement of the blade ring when moving through its operating stroke. The other end of lever 302 includes a gear segment 304 which meshes with a pinion 305 constituting one element of a gear train, the remainder of which is not shown. The farther the nose 303 of lever 302 is allowed to move into the path of the pin 26, the more retard action there is placed on the blade-operating ring and, hence, the slower the shutter speed. The position of the lever 302 is controlled by the speed control ring 30I which includes an opening 306 through which a pin 30'! on the end 304 of the lever 302 extends; said opening having a stepped cam surface 308 against which the pin 301 is forced by a spring, not shown, normally acting to move lever 302 in a counter-clockwise direction. In other words, the steps on cam surface 308 determine the position of nose 303-01 lever 302 relative to the path of travel of pin 23 on blade ring 23 and, consequently, the amount of retard action which is placed on the blade operating mechanism. As the speed control ring 30I is oscillated in accordance with the speed scale 8 on the cover plate 2, the proper step of cam surface 308 is moved opposite pin 331 to give this desired speed. As will be clear from an inspection of Fig. 3, when the speed control ring is set at /1 or't speed, the pin 30! will be confined in an arcuate portion 400 of the opening 306 so that the nose 303 of lever 302 will be removed entirely from the path of pin 26- on the blade ring and no retard action will be imposed on the blade mechanism. The diiference between ,4 and 170O speed is obtained in. this shutter by the automatic inclusion of a booster spring for the speed, but, since this is not essential to the present invention, this is notshown.

Looking now at Figs. 3 and 4, the speed control cam 30!! which is attached to the speed control ring 30I lies directly above the synchronizer adjusting ring I30 so that when the ring I 33 is adjusted for class M lamps, the lug 20I connected to switch contact 1 I5 ext nds upwardly suihciently to engage cam 300. It will thus be seen that when the speed control ring is adjusted to give different shutter speeds, then earn 305 thereon will take over and adjust contact H5 relative to contact II6 to vary the closing time of the switch. This cam 33B is so calc' lated as to adjust the flash switch to give the desired and best possible speed and light combinations as discussed above. For instance, if the shutter is set for time of a second speed, then the low point of t e cam 303 will be opposite the lug 28I to allow contact I I5 to move close to contact H6 and thus accommodate the maximum or 19-20 millisecond lag of the lamp. In this position, the cam 360 is coplanar with cam H2 and isessentially inoperative. However, as the speed control ring ismoved clockwise to give slower shutter speeds, cam 300 takes over full control of lug 20I and contact II5 fromv the synchronizer cam I I2 and keeps reducing the delay time between switch closing and shutter release until at a & speed the delay time is only about 7-8 milliseconds. In the position shown in Fig. 3, the speed control ring is adjusted for speed and cam 300 has adjusted contact I I5 relative to contact I I6 to give a 11-12 millisecond delay between closing of the ,flash switch and release of the shutter.

It will be observed that when the synchronizer camv ring I00 isadjusted to accommodate class flashlamps that lug 25H of contact H5. is moved out of engagement with speed control cam 330 and is not affected by adjustment of the speed control ring. This is in accordance with the discussion above to the effect that because of the flash characteristics of this class of lamp, no adjustments as to shutter speed are really required. If it were decided, however, that such. adjust.- ments were needed, another speed cam, like cam 363 but with a different curve, could be added to the speed control rin to come into play when the synchronizer was adjusted for class F" lamps. By virtue of the disclosed arrangement of parts, namely the disposition of cams H2 and 330, it will be apparent that speed control cam 300 will be automatically brought into operative relation with lug 20I when the synchronizer is adjusted by cam II2 to accommodate class M lamps.

While I have shown and described my invention. in combination with a particular form of between-the-lens type shutter and having a particular form of built-in flash synchronizer, it will be readily understood that it could be applied to any form of flash synchronizer which is adjust- .able to accommodate the different classes of flashlamps. For instance, in US. Patent 2,319,086, Riddell, May 11, 1943, there is shown a built-in synchronizer including switch contacts 5| and 62,

the former being adjustable relative to the latter through the use of cam I8 on control ring IT to adjust the time of relativeclosing of the flash switch with the opening of the shutter blades to accommodate different classes of flashlamps. Furthermore, this patent shows a shutter and synchronizer combination wherein the flash switch is operated by the opening movementof the blade driving means, rather than by the operationof the sh tter release mechanism. It will be obvious that the speed control ring of this shutter, not shown, could be provided with a cam, like cam 300 in the pres nt disclosure, which would take over and further adjust upstanding fin er I5 and, hence, switch contact 5| when control ring Tl wasset for lamps havinga 20-millisecond "lag (class M) and thus further adjust the switch to obtain the best possible speed and light combination for this class of lamps in accordance with the present invention.

Althoigh I have shown and described certain specific embodiments of my invention, I am fully aware that many modifications thereof are possible. My invention therefore is not to be restricted except insofar as is necessitated by the scope of the appended claims.

Having thus described my invention, what I claim is new and desire to secure by Letters Patent of the United States is:

1. In a photographic shutter the combination with shutter blades; a blade operating mechanism for controlling the opening and closing of said blades; a speed control member adapted to be selectively positioned to vary the speed of operation of a part of said blade operating mechanism involved in the actual opening and closing or the blades; 8, flash synchronizer mechanism comprising a normally open switch adapted to be connected into an electric circuit controlling the ignition of a flash lamp of the F class or M class; said switch arranged to be closed by a part of said blade operating mechanism in timed relation to the opening of said shutter blades thereby to accommodate for the lag" of the flash lamp to be used; said switch being adjustable to alter the time of closing thereof relative to the blade opening movement of said blade operatin mechanism; means for selectively adjusting said switch to adjust the time of closure thereof in accordance with the lag characteristic of either the F class or M class flash lamps; of means for further adjusting said switch to automatically alter the time of closure thereof in accordance with selected exposure speeds, and including mean operatively connecting said speed control member and said switch whereby said switch is adjusted by movement of said speed control member.

2. In a photographic shutter the combination with shutter blades; a blade operating mechanism for controlling the opening and closing of said blades; a speed control member adapted to be selectively positioned to vary the speed of operation of a part of said blade operating mechanism involved in the actual opening and closing of the blades; a flash synchronizer mechanism comprising a normally open switch adapted to be connected into an electric circuit controlling the ignition of a flash lamp of the F class or M class; said switch arranged to be closed by a part of said blade operating mechanism in timed relation to the opening of said shutter blades thereby to accomodate for the "lag of the flash lamp to be used; said switch being adjustable to alter the time of closing thereof relative to the blade opening movement of said blade operating mechanism; means for selectively adjusting said switch to adjust the time of closure thereof in accordance with the lag characteristic of either the F" class or M class flash lamps; of means for further adjusting said switch to automatically alter the time of closure thereof in accordance with the selected exposure speed when using lamps of the "M" class, said last mentioned means including means operatively connecting said speed control member and said switch whereby said switch is adjusted by and in accordance with movement of said speed control member; and means for automatically rendering said operative connection between said speed control ring and switch effective and ineffective as said first mentioned or selective switch adjusting means is moved to and from, respectively, the position to accommodate M class lamps.

3. In a photographic shutter the combination with shutter blades; a blade operating mechanism for controlling the opening and closing of said blades; a speed control member adapted to be selectively positioned to vary the speed of operation of a part of said blade operating mech anism involved in the actual opening and closing of the blades; a flash synchronizer mechanism comprising a normally open switch adapted to be connected into an electric circuit controlling the ignition of a flash lamp of the F" class or M class; said switch comprising a pair 01' normally spaced contacts, one of said contacts adapted to be engaged and moved into switch closing relation with the second contact by a part of said blade operating mechanism when moving to open the shutter, means for selectively adjusting said second contact relative to the first contact to alter the time of closing of said switch in accordance with the lag characteristics of class F" or class M lamps; of means for further adjusting said second contact to automatically alter the time of closure thereof in accordance with selected exposure speeds, and including a cam means moved by said speed control member and having its curve operatively engaging said second contact to adjust said contact as said speed control member is moved.

4. In a photographic shutter the combination with shutter blades; a blade operating mechanism for controlling the opening and closing of said blades; a speed control member adapted to be selectively positioned to vary the speed of operation of a part of said blade operating mechanism involved in the actual opening and closing of the blades; a flash synchronizer mechanism comprising a normally open switch adapted to be connected into an electric circuit controlling the ignition of a flash lamp of the F class or M class; said switch comprising a pair of normally spaced contacts, one of said contacts adapted to be engaged and moved into switch closing relation with the second contact by a part of said blade operating mechanism when moving to open the shutter, means for selectively adjusting said second contact relative to the first contact to alter the time of closing of said switch in accordance with the lag" characteristics of class F or class "M lamps; of means for further adjusting said second contact to automatically alter the time of closure of said switch in accordance with selected exposure speeds when said selective switch adjusting means is positioned to accommodate class M" lamps, and including a cam carried by said speed control member to move therewith, the curve of said cam operatively engaging said second contact to control movement thereof relative to said first contact.

5. In a photographic shutter the combination with shutter blades; a blade operating mechanism for controlling the opening and closing of said blades; a speed control member adapted to be selectively positioned to vary the speed of operation of a part of said blade operating mechanism involved in the actual opening and closing of the blades; a flash synchronizer mechanism comprising a normally open switch adapted to be connected into an electric circuit controlling the ignition of a flash lamp of the F class or "M class; said switch comprising a pair of normally spaced contacts, one of said contacts adapted to be engaged and moved into switch closing relation with the second contact by a part of said blade operating mechanism when moving to open the shutter, means for selectively adjusting said second contact relative to the first contact to alter the time of closing of said switch in accordance with the lag" characteristics of class "F" or class M lamps; of means for further adjusting said second contact to automatically alter the time of closure of said switch in accordance with selected exposure speeds when said selective switch adjusting means is positioned to accommodate class M lamps, and including a cam carried by said speed control member to move therewith, the curve of said cam operatively engaging said second contact to control movement thereof relative to said first contact, and means for automatically connecting and disconnecting said operative engagement between said cam and second contact when said selective switch adjusting means is moved to and from, respectively, the position to accommodate class M lamps.

6. In a photographic shutter the combination with shutter blades; a blade-operating mecha nism for controlling the opening and closing of said blades; a speed control member adapted to be selectively positioned to vary the speed of operation of a part of said bladeoperating mechanism; a flash synchronizer mechanism comprising a normally open switch adapted to be connected into an electric circuit controlling the ignition of a flash lamp having a characteristic lag; said switch arranged to be closed by a part of said blade-operating mechanism in timed relation to the opening of said shutter blades thereby in order to accommodate for the lag of said flash lamp; said switch being adjustable to alter the time of closing thereof relative to the blade-opening movement of said blade-operating mechanism; of means for adjusting said switch to automatically alter the time of closure thereof in accordance with the selected exposure speed, and including a cam connected to said speed control member to be moved by adjustment thereof, said cam directly engaging a part of said switch to adjust the time of closing thereof.

7. In a photographic shutter the combination with shutter blades; a blade-operating mechanism for controlling the opening and closing of said blades; a speed control member adapted to be selectively positioned to vary the speed of operation of a part of said blade-operating mechanism; a flash synchronizer mechanism comprising a normally open switch adapted to be connected into an electric circuit controlling the ignition of a flash lamp having a characteristic lag, said switch comprising a pair of normally spaced con tacts, one of said contacts adapted to be moved into engagement with the second by a part of said blade-operating mechanism to close the switch in timed relation to the opening of said shutter blades in order to accommodate for the lag of said flash lamp; said switch being adjustable to alter the time of closing thereof relative to the blade-opening movement of said blade-operating mechanism; of means for adjusting said switch to automatically alter the time of closure thereof in accordance with the selected exposure speed, and including a cam connected to said speed control member to be moved by adjustment thereof, said cam connected to the second contact of said switch to adjust the separation between it and said first contact to alter the time of closing thereof.

8. In a photographic shutter of the setting type the combination with shutter blades; a bladeoperating mechanism for controlling the opening and closing of said blades when moving from a cooked condition; a release mechanism for releasing said blade-operating mechanism from its cocked condition; a speed control member adapted to be selectively positioned to vary the speed of operation of a part of said blade-operating mechanism; a flash synchronizer mechanism comprising a pair of normally spaced switch contacts adapted to be connected into an electric circuit controlling the ignition of a flash lamp having a characteristic lag; means for connecting one of said switch contacts to said release mechanism to be moved into engagement with the second contact upon movement of said release mechanism to a shutter-releasing position and in timed relation with the release of said blade-operating mechanism thereby; of means for automatically altering the relative time of closing of said switch and the release of said blade-operating means by said release mechanism to accommodate for the lag of the flash lamp and the selected exposure speed, and includingan operative connection between said speed control member and the synchronizer mechanism whereby the time of closing of said switch relative to the release of said blade-operating mechanism from a cocked condition is automatically adjusted by movement of said speed control member.

CARL C. FUERST.

CES CITED The following references are of record in the is of this patent:

UNITED STATES PATENTS Number Name Date 2,298,107 Carr Oct. 6, 1942 2,429,972 Aiken Nov. 4, 1947 2,435,161 Schwarz Jan. 27, 1948 2,455,365 Jenner Dec. 7, 1948

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