US2045118A - Timing device - Google Patents

Description

J. J. BRQWN TIMING DEVICE June 23, 1936.;

Filed March 26, 1934 2 Sheets-Sheet l Y wT/V w36., I J. J. BROWN l 2,045,118

TMING DEVICE Filed March 26, 1934 2 Sheets-Sheet 2 INVENTOR /evw A ORNEYS Patented June 23, 1936 UNITED STAT ES 04ans PATENT GFFICE 7 Claims.

IIhe present invention relates broadly to a timing device and more specifically-to an electrical timing switch.

'It comprises a device for timing'the operation of a mechanism, for'example, aphotographic printer, in such manner that the printer may be controlled to be operative for a given time interval and also 'wherein the` devicewmay be easily'rendered ineffective, so that its effective operation may be `delayed under the will of an operator whenever it is desirable to Vretain -an intermediate controlfor a substantial period of time.

The specific embodiment herein disclosed-*of the present invention is an electrically controlled time switch for a printer-for photographicpurposes. In lmaking prints or enlargements of photographs, it is desirable to controlthe effective time whenthe printing light is operative upon the sensitized paper -or other printing' medium on which the photograph is beingprinted. In the commercial printing of photographsfwhere time of operation controls the 'speed of production, it is desirable that the photograph be printedwithin a few seconds, which means that the tolerances as to time of printing light are narrow, assuming, of course,that the source of light is of substantially constant intensityfthat is; affraction Aof a second variation may mean an under-exposed or Van vover-exposed print, as-the'case mayfbe.

The preferred embodiment of the-present invention comprises a iluid filledcylinder through which a weighted piston is adapted to be moved by gravity. The embodiment herewith, as will be hereinafter described in detail by referencel to the drawings, comprises asymmetric apparatus with both ends of the cylinder effective for-the purposes desired. There is an electric switch at each end of thecylinder. These switches are connected in series so that the opening of. either switch breaks the circuit. Assuming the-Weighted piston to be at one end ofthe cylinder `and-the cylinder to be inverted, theweight of the piston will be supported by the iiuidin the cylinder conned beneaththe piston. The release of the fluid beneath the plstonwill control 'the'rate of' fall of the piston. This confined uid may be bypassed relative to the pistonin-such manner as to be permitted to flow frombeneath the piston to a space above the piston. The by-pass is controlled by a suitable adjustable valve so that the rate of release of the fluid beneath the descending piston, is controlled, 'thereby determining the 4time interval for the piston to descend the length of the cylinder. This. by-pass construction,

rthereby lighting the printing light.

(Cl. vW-34:)

whereby fluidisv lay-passed from one side of the piston to the other, provides a self-contained device. in which asuitable iiuid maybe sealed to insureagainst loss, and to prevent contamination y from dust and dirt. Any gas or liquid which does not vary a substantial amount in viscosity at nor- .mal room temperature variations is best suited for the present invention. When the piston reaches the lower limit of its travel, the weight ofthe piston operates, in the specific embodiment herewith, an electrical switch which opens a circuit and thereby cuts off the printing light.

vIn the specific embodiment herewith, the cylinder is mounted upon trunnions and is adapted to be oscillated relative toits longitudinal axis, so that the cylinder may alternately be inverted end for end. The control valve in the by-pass is set so that the time interval of the travel of the piston from vone end of the cylinder to the other corresponds tothe time a proper printing light is effective to properly expose a suitable sensitized paper or other medium through a predetermined,` negative. When fthe paper `and. negative are properly assembled in a suitable printing ap- Y paratus, the operator inverts the cylinder. 'The piston which has been resting on the bottomof ythe cylinder is now at the top and starts to -the cylinder. i The 'piston again travels downward-under the inuence of gravity and as soon Vas thefweight ofthe piston is released from the switch which it has opened, this switch closes, This light stays lighted until the piston has descended sufyciently to operate the other switch at the now lower end of the cylinder. These operationstare continued until the desired number of prints are made when the next negative'is tested as to density. The control valve may be reset accordingly and the operations are repeated. The cylinder may be held in a horizontal position to retain the' light lighted whenever this is desirable.

While thepresent invention is adapted to and isexplained with reference to its operation in connection with'photographic apparatus, it is to be understoodthat'the invention may be useful for other ftiming operations.

It is recognized that the present invention may loe embodieduin v.structures differing from those specifically disclosed herewith, and, therefore, it is desired that the disclosure herewith shall be understood as illustrative and not in the limiting sense.

Fig. 1 illustrates a section of the device on line of Fig. 3.

Fig. 2 illustrates a section of the device on line 2 2 of Fig. 3.

Fig. 3 shows a section of the device on line 3--3 of Fig. 2.

Fig. 4 shows a diagrammatic illustration of the device as applied to a light adapted for photographic printing.

Fig. 5 illustrates a mechanism for oscillating the device by a foot pedal.

Referring to the drawings and more especial- 1y to Fig. 1, the device comprises a body portion I having a cylindrical bore 2 with a tubular passageway 4 in communication with the cylindrical bore 2 by means of ports 5 and 6. A Weighted piston 'I substantially fitting the cylindrical bore 2 is adapted to travel lengthwise therein under the influence of gravity when the body portion of the cylinder is inclined suiciently toward the vertical to cause gravity to overcome friction of the piston 'I on the side wall of the cylindrical bore 2. The ends of the cylindrical bore are closed by end plates 3. Preferably, the body portion I and the end plates 8 are formed of materials capable of being joined together in such manner as to provide a hermetic seal and in the present case, the body portion I and the end plates 8 are of metal and the entire outside joint between the end of the body portion and the end plates 8 is closed or sealed by welding as at 9. This obviates any possibility of the escape of the liquid I0 by evaporation or otherwise. This preferably comprises an oil or other fluid which is not subject to substantial expansion or contraction Within normal atmospheric temperature ranges and which does not substantially change in viscosity with such temperature changes. Each end plate 8 carries thereon a sylphon member I. The sylphons are united to the end plates in such manner as to form a hermetic seal and in the present case, the sylphons preferably are of metal and are Welded to the metal end plates 8. The sylphons II allow expansion and contraction of the fluid due to temperature changes. The sylphons also comprise devices by which terminal movements of the piston 'I may be communicated to an operating part such as an electrical switch. Cap members I2 are mounted upon the end plates 8 by suitable stub screws |4 or other convenient uniting members and these cap members may carry electrical switches I 5. Preferably, coil springs |6 extend between the cap members I2 and the ends of the sylphons II to assist the movement of the sylphons away from the operating members I1 of the switches I5 when not being weighted down by the pistons. In order that trapped air may not interfere with the free operation of the sylphon members, ports I8 may be provided through the cap members I2. A conduit I9 is provided for suitable electrical connections to the electrical switches I5. Preferably, the body member is provided at its central portion with a pair of oppositely disposed trunnions 2li and 2|. The

trunnion 2| preferably is provided with an opening 22 leading to the conduit I9 to provide an outlet for the electrical wires leading to the switches I5 so that these wires may be connected with a suitable electrical circuit 24 which is under control of the switches I5.

The electric circuit 24 may include an electric lamp 25 and the circuit is supplied with current by a suitable source of electrical energy. 'I'his electrical lamp 25 is the operating lamp for a photographic printed 26. Photographic printers are well known in the art, and, therefore, for purposes of simplification, the photographic printer 26 is merely illustrated diagrammatically.

The tubular passageway comprising the by-pass 4 is controlled by an adjustable valve. This adjustable valve may comprise a Valve head 21 of sufficient size to completely block the passage-- Way 4 and to be provided with a valve seat 28 so' that the passageway 4 is entirely closed when the valve head is completely seated. The valve head carries a threaded extension 29 upon which is mounted an adjustment nut 30 which bears against a valve casing 3|. A metallic sylphon 32 is hermetically sealed to the valve head 21 and is also hermetically sealed to the valve casing 3| as for example, by welding. A coiled spring 34 normally urges the valve head 2l toward the valve seat 28. This action of the spring 34 is resisted by adjustment of the adjustment nut on the threaded extension 29 so that the valve may be set at any predetermined degree of opening. The valve casing 3| is hermetically sealed to the body portion I of the cylinder as by welding as at 35. This construction of the valve is such that no leakage of liquid is possible through the valve casing to the exterior of the parts. In order to obviate any diiioulty in operating the valve due to possible leakage around the valve head 2l into the casing 3|, a small port opening 35 is provided between the space in the 'casing 3| and the by-pass 4.

'I'he device may be mounted in different ways for operation, but preferably, is mounted in accordance with the illustration in Fig. 5 wherein the trunnions 2i) and 2| are mounted to oscillate in bearing brackets 31. A link 38 may be pivoted to the boss 39 (Fig. 2) on the body portion I and is connected at the other end with the vertical arm of a bell crank 4il mounted Ito oscillate in a frame bracket 4|. An adjustable stop 42 adjusts the limit of movement of the bell crank 40 in one direction so that when the lower arm of the bell crank 4l) is in contact with the stop, the position of the parts will be such as to maintain the body portion of the cylinder with the longitudinal axis thereof substantially vertical. A pedal 44 mounted on a pedal bracket 45 is connected by a link 45 with a horizontal arm of the bell crank 4B. A spring 41 normally maintains the forward end of the pedal raised and the lower arm of the bell crank in contact with the adjustable stop 42. A pivoted latch 48 may be provided in front of the pedal so that it may be moved forward as the operator desires to hold the pedal in its lower position whenever this is desirable.

The operation of these parts is such that when the pedal 44 is depressed, the link 38 pulls forward, thereby swinging the cylinder on the trunnions and the momentum of the swinging movement carries the cylinder beyond dead center, so that when the pedal rises, the boss 3S swings to the position 49 indicated in dotted lines in Fig. 5, and the lower arm of the bell crank 40 comes into contact with the adjustable stop 42 leaving the cylinder in inverted position. The piston descends under the influence of gravity and displaces the iluid beneath the piston. The displaced fluid re-enters the chamber above the piston. The rate or speed of descent of the piston through a portion of its travel is determined by the setting of the control valve. A succeeding Apressurezon'zthei pedalJSand-release thereofucauses .theylinderLtoktumfiend for end tolthe' position ,'showninlfullllinesin Figi. 5. 'Thus; it will--beseen .lthat ".-byz depressing fthe pedal-fand "releasinguthe 5 same the Y cylinderli may Abesuccessively 'L inverted fendlforrend Whereiitis' desirable thatthelight be-retained on continuously for` a"'substanti'al i length@ off. time; the. pedal. f is pushed down.. and -pivoted vvlatch` 48. I is :moved over..the -irend of i the Yl pedal, thereby latching it in its lowerlposition. When this happens, `the cylinderl :will assume an -inclined position aszindi'cated -xby the .'dotted line lll'in Fig. 5.

hen thecylinderK is.` inclined, .thel weightof the l piston f is removednfromV :the sylphonwithzwhich the piston has been in'.engagementandthe` spring |61zexpands the sylphon to. allow vthesWitch. `I5 v.todcl'ose 'While the inclination needibe` only slightly beyond ".thei` horizontal, .it shouldbe. sufflcient to allow the release of the weight from the sylphon, and should be enough to insure that the effect of gravity on the piston is in the direction to tend to move the piston away from the sylphon, but not enough to cause the piston to move under influence of gravity alone.

When the cylinder is in this inclined position, the switches at both ends of the cylinder are closed and the light may be retained lighted so long as the cylinder is held in this inclined position. When it is desired that operations shall be resumed, the latch 48 is released and the cylinder will assume a vertical position as indicated in full lines in Fig. 5.

When the cylinder is in vertical position with the piston in the upper end of the cylinder, gravity operating on the piston causes the same to descend. By reference to Figs. l and 2, it will be noted that ports 6-6 are located adjacent the ends of the cylindrical bore beyond the path of movement of the piston 1, while ports 5 5 are located within the path of movement of the piston. When the piston rst starts to descend, no substantial retarding action occurs because the fluid is freely by-passed through the ports 5 and B adjacent the upper end of t-he cylinder. This permits the piston to move quickly away from the upper sylphon and permits the upper switch to close. Since the lower switch is already closed, the circuit is now completed. As the piston moves downward, it closes the upper port 5,

whereby fluid beneath the piston must now be bypassed through the control Valve 21 and the travel of the piston is thereby retarded in accordance with the setting of this valve, until the piston has descended suiiiciently to open the lower port 5,

at which time the fluid beneath the piston is bypassed rapidly from the lower port E through the lower port 5 which is now above the piston, and the piston has reached the position indicated in Figs. 1 and 2. The arrangement of the ports 5 and 6 eliminates further retarding action by the valve 21 and permits the piston to move quickly toward the lower end of the cylinder, thereby exerting the full weight of the piston on the lower sylphon and switch mechanism to quickly open the switch I 5 in the lower end of the cylinder.

The ports 5-5 and 6-6 should each be at least of the same capacity as the conduit 4. By this arrangement, it will be observed that during the initial and nal travel of the piston, it is not substantially retarded in its movement, but as quickly as the piston closes the upper port 5, the further movement of the piston is under control of the control valve 21, until the piston has descended sufciently to open the lower port 5 at which time-the-.travel Yof 'the' piston iswagain lindependent of the control valve 21. The piston 1 -is vin effect -afrnovable wallE dividing the cylinder :into lLtwol chambers, -one of -which contains "iluid under slight compression-when theweight of--the 155 piston-is supported by thesaid fluid.

, Itwill be observed that the present device-de- -Ipendsfor its'timing features upon fluid flow and .-is, therefore, *independentv of `mechanical clock mechanism or of electrical circuit characteristics, .10 and consequentlymay be operated in connection with any -type of electrical circuit either 'alternat- "ingor'direct current.' The present device provides a simple and eflicient timing mechanism for the Vpurposesintended. '15

AlWhat isv claimed is:

1; A device of the class described comprising a hermetically sealed cylinder, a piston movable byigravityfwithin said cylinder, sylphon members "hermetically sealed to the end walls of said cylin-fD der and beingl adapted to be collapsed by 'the weight of said piston, electrical switches operated by said sylphons, and means to control the speed of movement of said piston relative to said cylinder. 25

2. A hermetically sealed cylinder, a piston movable within said cylinder, sylphons hermetically sealed to the end walls of said cylinder, a bypass connected with the ends of said cylinder, said cylinder being lled with a fluid, said uid being 30 adapted to iiow through said by-pass when said piston moves within said cylinder, a valve for controlling the rate of flow of fluid through said by-pass, said valve being operatively connected to a hermetically sealed sylphon, electrical switches 35 mounted within the sylphons carried by the end walls of the cylinder, and means for oscillating said cylinder to cause the said piston to move therein.

3. A device of the class described, a chamber, 40 a piston slidable in said chamber, said chamber containing a fluid, a conduit in communication with both sides of said piston whereby the movement of the piston displaces fluid from one side of the piston and replaces the fluid on the 45 opposite side thereof, control means for regulating the rate of flow of said fluid through said conduit, and relief ports connecting said chamber with said conduit so as to render said control means ineffective when the piston passes a pre- 50 determined point in the chamber.

4. A hermetically sealed cylinder, a piston movable by gravity within said cylinder, bellows or diaphragms hermetically sealed into the ends of' said cylinder and adapted to having motion im- 55 parted thereto by the movement of said piston, a by-pass connecting the ends of the cylinder, said cylinder being filled with a uid, said fluid being adapted to flow thru said by-pass when said piston moves within said cylinder, a control valve 50 for regulating the rate of flow cf said fluid thru the by-pass, said control valve being operatively connected to a hermetically sealed bellows or diaphragm, electrical switches adapted to be operated by the movement of the first-mentioned 65 bellows or diaphragms when Same are actuated by the movement of the piston, and relief ports connecting said cylinder with said by-pass, said relief ports being so located in relation to the travel of the piston and in relation to the loca- 70 tion of the said control valve that the iiuid below the piston is freely by-passed thru the nearest relief port to the space above the piston independent of the action of the said control valve at 75 a time just prior to the piston reaching the end of its travel.

5. A hermetically sealed cylinder, a piston movable by gravity Within said cylinder, bellows or diaphragms hermetically sealed into the ends of Said cylinder and adapted to having motion imparted thereto by the movement of said piston, a by-pass connecting the ends of the cylinder, said cylinder being lled with a fluid, said fluid being adapted to ow thru said by-pass when said piston moves within said cylinder, a control valve for regulating the rate of ow of said fluid thru the by-pass, said control valve being operatively connected to a, hermetically sealed bellows or diaphragm, and electrical switches adapted to be operated by the movement of the mst-mentioned bellows or diaphragms when same are actuated by the movement of the piston.

6. A hermetically sealed cylinder, a piston movable by gravity Within said cylinder, bellows or diaphragms hermetically sealed into the ends of said cylinder and adapted to having motion imparted thereto by the movement of said piston, a by-pass connecting the ends of the cylinder, said cylinder being filled with a fluid, said fluid being adapted to oW thru said by-pass when said v piston moves Within said cylinder, and a. control valve for regulating the rate of flow of said uid thru the by-pass, said control valve being operatively connected to a hermetically sealed bellows or diaphragm.

7. A hermetically sealed cylinder, a piston movable by gravity Within said cylinder, bellows or diaphragms hermetically sealed into the ends of said cylinder and adapted to having motion imparted thereto by the movement of said piston, a l

by-pass connecting the ends of the cylinder, said cylinder being lled with a uid, and said uid being adapted to ow through said by-pass when said piston moves within said cylinder.

JESSE J. BROWN.

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