Патент USA US2407800код для вставки
Sept. 17, 1946. R. |_, sM|T|-| 2,407,800 EXPOSURE TIMING MECHANISM Filed Jan; 26, 1945' Tag5/19 2/ I \ >9 ”’ /0 - INVENTOR: Patented Sept. 17, 1946 2,407,800 UNITED STATES PATENT OFFICE 2,407,800 EXPOSURE TIMING MECHANISM Roland L. Smith, Belmont, Mass. Application January 26, 1945, Serial No. 574,662 6 Claims. (Cl. 161-1) 1 2 This invention relates to exposure timing mechanisms such as are employed in making mind the length of time, as measured in seconds, photographic enlargements and prints by electric light. A timing mechanism of the class referred to is employed for controlling and operating an for each exposure since no indication of this. factor could be derived from the instrument itself, Another objectionable feature of devices of this class as heretofore provided has been that when the dial was constructed with a supplemental electric circuit in which is arranged an electric series of holes or sockets, more closely spaced lamp by means of which the enlarging or ‘print apart than the ?nger holes or sockets, for use in ing is effected and such a device is, as a practi cal matter, essential when a number of prints or 10 effecting exposures differing in time from that possible through use of the ?nger holes, said enlargements are to be produced from a single supplemental holes or sockets were necessarily negative if uniformity in results is to be obtained. made too small for the reception of the ?nger A well known type of timing instrument has so that it was necessary for the operator to equip heretofore been provided which comprised a ?nger-operated rotatable dial, a spring motor for 15 himself with a pointed skewer-like accessory in strument such as a pencil, for example, for use yieldingly urging said dial rotatively in one direc within the small supplemental holes when op tion at a predetermined speed, a switch incorpo erating the dial. rated in the circuit of the lamp, said switch in This invention has for its object to provide cluding a resilient contact serving also as a stop for limiting the rotary movement of the dial 20 an improved timing instrument of the class de scribed and in particular to obviate the above under the in?uence of the spring motor and be ing normally maintained in open position by the noted objectionable features characterizing de dial, and a ?nger-engaging stop on the frame or vices of this class as heretofore constructed. To this end I have provided certain improve base of the instrument for limiting the rotary movement of the dial in the opposite direction 25 ments in instruments of the class indicated as set forth in the following description, the several under the influence of the ?nger oi the operator. novel features of the invention being separately The dial was made with a circular series of sockets or apertures spaced apart equidistantly at pointed out and de?ned in the claims at the close of the description, it being understood, however, intervals of a predetermined number of seconds, usually ?ve seconds, and in making an exposure, 30 that the illustrated embodiments of the inven tion are to be taken as preferred examples of the say for example ?fteen seconds, the operator latter and that various changes may be resorted would insert his ?nger in the third aperture or to without departing from my invention as de socket in front of the ?nger stop and quickly turn ?ned in the claims. the dial clockwise away from the switch until In the accompanying drawing: movement of his ?nger and the dial in that direc 35 Figure 1 is a top plan view of an exposure tim tion were arrested by said ?nger stop whereupon the operator released the dial thereby permitting ing instrument constructed in accordance with this invention. the spring motor to return the same contra clockwise to its normal position again at said pre Figure 2 is a side elevation, partly in section, of determined speed. At the start of the movement 40 the instrument shown in Fig, 1. Figure 3 is a section on line 3-3 of Figs. 1 of the dial under the in?uence of the operator’s and 2. ?nger the resilient contact was released thereby Figure 4 is a sectional detail relating to the dial closing the circuit through the lamp, and at the of Figs. 1 and 2. completion of the return movement of the dial Figure 5 is a partial top plan view of an ex under the in?uence of the spring motor the re-, 45 posure timing mechanism embodying an alter silient contact was restored to its normally open position by the dial thereby extinguishing the native form of the invention. Figure 6 is a side view of the parts shown in lamp at the expiration of the selected interval of Fig. 5. time-?fteen seconds. An objectionable feature characterizing the 50 Figure '7 is a detail hereinafter referred to re lating to the embodiment illustrated in Figs. 5 above described and other constructions hereto fore proposed has been that in making many en and 6. largements or prints from one and the same The embodiment of my invention illustrated in Figs. 1, 2, 3, and 4 of the drawing comprises negative it was necessary, throughout this pro cedure, for the operator to remember or bear in 55 a molded base 10 of any suitable non-conducting 2,407,800 3 moldable material, said base being in the form of an inverted cup which provides a housing for a spring motor I I and an electric switch comprising a ?xed contact I2 and a resilient contact l3. Contacts I2 and [3 are arranged in an electric circuit I4 in series with the usual electric lamp 4 it is possible to provide for an exposure that prevails for a de?nite measured length of time appropriate to the characteristics of the particu lar negative or the like that is being employed, provided said appropriate time is ?ve seconds or a multiple of ?ve seconds. (not shown) by means of which the photographic The above described construction is as here tofore and serves its purpose very well when making a small number of enlargements or prints Spring motor II is fastened by screws Ila (Fig. 10 from a single negative or the like requiring com 1) to the under side of the top wall of base I0 paratively long exposures, but when making a and includes a vertical shaft 15 which extends considerable number of enlargements from one upwardly therefrom loosely through an aperture and the same negative or the like, the operator provided in the top wall of base It! to the ex would often inadvertently use the wrong ?nger terior thereof where it has ?xedly mounted on 1.5 hole during his repeated operations of the dial it a circular molded dial I6 that is formed near because of the absence of any means for visually its periphery with a circular row of ?nger holes indicating the proper hole to use. Moreover, or sockets I1 disposed concentrically with respect when operating with a thin negative requiring to the axis of motor shaft I5. short accurately timed exposures other than of Upon its under side the dial I6 is made with 20 five seconds or a multiple thereof, it was not a depending boss IB which is normally pressed possible to operate the instrument accurately as laterally against one side of the upper end of required except through the use of the accessory the resilient contact I3 by motor l I so as to hold skewer-like implement and the relatively small said contact out of engagement with the ?xed supplemental holes or sockets, hereinbefore re contact I2. The ?xed contact I2 is disposed en~ ferred to. My improvements, now to be de tirely within base I0 where it is fastened by scribed, obviate these objectionable features char screws to a pad I9 (Figs. 2 and 3) forming part acterizing instruments of this kind as heretofore of the top wall of the base. The resilient con constructed and with which I am familiar. tact I3 is fastened by screws to another pad Ell In accordance with this invention I provide forming part of the top wall of the base and the timer mechanism with a ?nger-operated arm includes a free end portion extending upwardly 24 (Fig. 1) of resilient sheet metal disposed through an aperture ZI formed in the top wall radially above, and in close proximity to, the dial of the base to the exterior of the latter where I6, said arm being pivotally secured at its inner its upper extremity occupies a position in the end to the upper end of the motor shaft I5 by path of the boss I8. One side of this aperture - a screw 25 so that it is normally free to be swung 2! serves as a stop to positively limit the move laterally relatively to said shaft and the dial in ment of contact I3 occasioned by the pressure either direction. The outer end of this arm is of the boss against the same. provided with a depending ratchet tang 26 (Figs. A bracket 22 is fastened by screws to the ex 2 and 4) to cooperate with a composite circular terior of base It and the upper end portion row or series of relatively small closely spaced of said bracket is made with a lateral ?nger?stop sockets or recesses 21 and 28 formed in the mar-. extension 23 which overhangs the marginal por ginal portion of dial I 6 and disposed concen tion of dial I6 just above the path traversed by trically with respect to the axis of shaft I5. Each the ?nger-holes or sockets l1 when the dial is of these sockets or recesses is adapted to re— rotated on the axis of shaft I5. ceive the tang 26 as shown in Fig. 4 and pro The ?nger-holes or sockets I1 are angularly vides at one side thereof an abrupt abutment spaced apart relatively to each other alike shoulder facing away from stop 23 and adapted throughout the row a distance equaling the an~ to be engaged by one side of tang 25 which gular movement of shaft I5 during a predeter is parallel with said shoulder. The opposite side mined. length of time as measured by a number of tang 25 may be beveled as shown so that the of seconds and the angular distance between tang may slide freely over the sockets when arm hole or socket #1 and ?nger stop 23 is the same. 24 is rotatively adjusted in that direction. The Assuming this distance between the holes and resiliency of arm 24, however, permits the free between hole #1 and stop 23 to be equal to the end thereof to be manually lifted away from angular displacement of shaft I5 and dial I6 55 the dial when the arm is to be adjusted in either during an interval of time of ?ve seconds, as direction. in the drawing, it will be clear that by inserting Each socket 27 of the composite series is co a ?nger in either one of the holes I] and turn operatively associated with one of the ?nger-holes ing dial I6 and shaft l5 clockwise until movement of the dial in that when occupied by the tang of the ?nger and dial in that direction is ar 60 of arm 24 the latter then serves to indicate that rested by stop 23 and immediately releasing the the ?nger-hole associated with that socket is dial, then the spring motor will rotate dial I6 being used. This is an important function when and shaft I5 contra-clockwise back to their nor a number of enlargements or prints are being mal positions again and this return movement made from one and the same negative since will be effected by motor ll during a period of 65 it guides the photographer in his operation of time corresponding with the angular distance the dial and relieves him of the necessity of re between the hole that is used and the stop 23, membering the particular timing being employed. said period of time being either ?ve seconds or Arm 24 likewise serves as an indicator when en a multiple of ?ve seconds according to the posi gaged ‘with either of the sockets 28. tion of said hole. 70 When the dial occupies its normal position It will also be clear that during the time that the composite portion of the supplemental row‘ of enlargements or prints are made from a negative or the like. the dial is away from its normal position switch I2—~I3 is closed and the lamp (not shown) of sockets 2‘I—28 starts at the ?nger-stop 23 and extends therefrom contra-clockwise around the the apparatus is lighted. Thus, by using the marginal portion. of dia1 It as far as ?nger-hole proper hole or socket I’! in operating the dial 75 #6, an angular distance corresponding with the 2,407,800 5 distance traveled by the dial during thirty sec onds while being actuated by spring motor H and throughout this composite portion all of the sockets are spaced apart relatively equidistantly 6 teeth 29, said tang being yieldingly held against the dial by the resiliency of the arm of which it forms part. What I claim is: 1. In a timing instrument, the combination of a distance corresponding with the extent of an gular displacement of dial it e?ected by motor a rotatably supported switch-operating dial whose outer marginal portion is made with a con l l during a one second. period of time. centric row of ?nger-sockets angularly spaced In making enlargements from a thin negative apart equidistantly at relatively large intervals or the like not only is much less time required than with a dense or strong one, but much ?ner 10 and also with a concentric row of supplemental sockets spaced apart equidistantly at smaller regulation or control of the exposure period is necessary with the thinner negative or the like, angular intervals that subdivide the intervals which is, as Will be clear, obtainable through use between said ?nger-sockets; a radial arm pivot of arm 24 and the sockets of the composite por ally supported for independent rotative adjust tion of the supplemental row, the latter being 15 ment at times on the axis of said dial to set said spaced apart relatively one second. arm in a de?nite time-indicating position rela- When using a ?nger-hole or socket beyond the composite portion of the supplemental row, tively to said dial; a ?xed ?nger stop, and means on said arm for engaging one of said supple which will be the case in producing enlargements mental sockets to positively adjust said dial ro from a strong or dense negative or the like, the 20 tatively when said arm is swung by ?nger pres— arm as is set in engagement with the socket 21 sure toward said ?nger-stop. of the appropriate ?nger-hole and utilized in 2. The combination of claim 1 wherein said operating the dial. With this type of negative arm is a resilient member and wherein said last or the like regulation of the time of exposure mentioned means consists of a depending tang to the extent of ?ve seconds or multiple thereof 25 provided adjacent to the outer end of said arm is ordinarily suf?cient and this is provided for by and yieldingly held in socket-engaging position the ?ve seconds spacing of the ?nger-holes that by the resiliency of said arm. are beyond the composite portion of the supple 3. The combination of claim 1 wherein said mental row. ?nger-stop overhangs said dial and wherein the As shown in Fig. 2 of the drawing the stop 30 outer end portion of said arm is movable with said extension 23 is disposed above the path of the dial on a path between the latter and said ?nger dial operating arm 24 so that the latter can, at stop. times, pass beneath the same. 4. The combination of claim 1 wherein said In starting enlarging operations with a given supplemental sockets are provided by a circular thin negative the operator usually makes some 35 row of teeth formed upon the outer marginal por preliminary trial exposures by means of the ?nger tion of the dial. holes I‘! and after thus ascertaining the approx 5. The combination of claim 1 wherein said imate time he can then obtain the exact timing supplemental sockets are provided by a circular through use of the pawl-like arm 24 and the row of ratchet teeth formed upon the outer mar composite row of supplemental sockets 2'l—28. 40 ginal portion of the dial, and wherein said arm In many instances this will avoid the necessity is a resilient pawl-like member that is main~ of regulating the intensity of the light. tained in socket-engaging position by its resil In the embodiment of the invention illustrated iency. in Figs. 5. 6 and 7 the periphery of the dial [6a 6. In a timing instrument, in combination, a is made throughout its circuit with a circular row 45 rotatably supported switch-operating dial whose of ratch~like teeth 29 which provide abutment outer marginal portion is made with a row of shoulders 39 facing away from the ?xed ?nger relatively large ?nger-sockets that are angularly stop 23a, said shoulders co-operating with. a ver spaced apart at relatively large intervals con tically resilient pawl-like arm 24a. This arm is centrically with respect to the axis of said dial, pivoted loosely upon the upper end of the shaft 50 and made also with a concentric row of relatively 15 of the spring motor (not shown) and held in small supplemental sockets spaced apart at position thereon by a nut 25a having threaded smaller angular intervals that subdivide the in. engagement with said shaft. tervals between said ?nger-sockets; a spring mo The teeth 29 are spaced apart relatively an tor having a vertically disposed shaft on which angular distance corresponding with the extent 55 said dial is ?xed,_ said motor yieldingly main of rotary motion imparted to the dial by the taining said dial normally at the limit of its r0 spring motor during one second and within this tary movement in one direction; a radial ?nger circular row of teeth 29 the dial is formed with a operated arm pivotally mounted loosely upon said circular row of ?nger holes or socket-s I'ia which shaft for independent rotative adjustment are spaced apart relatively an angular distance thereon at times to set said arm in a de?nite corresponding with the extent of rotary motion time-indicating position relatively to said dial; imparted to the dial by the spring motor during means carried by said arm for engaging one of ?ve seconds, each of said holes or sockets Ila said ‘supplemental sockets to positively adjust being disposed radially opposite one of the abut said dial rotatively when said arm is swung by ment shoulders 30a of teeth 29 so that the holes ?nger pressure in the opposite direction, and a of the group or row Ila serve as indicators to ?xed ?nger-stop in the path of the ?nger for guide the operator in accurately placing the arm 24a in any desired position. limiting the movement of the dial in said oppo The free end of arm 24a is made with a de site direction. pending tang 26a (Fig. 7) to co-operate with the 70 ROLAND L. SMITH.