US2444170A

US2444170A - Photographic print conveying mechanism

Info

Publication number: US2444170A
Application number: US751592A
Authority: US
Inventors: Edward R Sabel; Frank I Galbrecht
Original assignee: Xerox Corp
Current assignee: Xerox Corp
Priority date: 1947-05-31
Filing date: 1947-05-31
Publication date: 1948-06-29
Anticipated expiration: 1965-06-29

Description

June 29, 1948. E. R. SABEL ET AL PHOTOGRAPHIC PRINT CONVEYING MECHANISM 5 Sheets-Sheet 1 Filed May 51, 1947 'June 29, 1948. E. R. SABEL ET AL PHOTOGRAPHIC PRINT CONVEYING MECHANISM 5 Sheets-Sheet 2 ll IIIIIIIIIIII Filed May 51, 1947 r M mwm INVENTORS June 29, 1948. E. R. SABEL ET AL PHOTOGRAPHIC PRINT CONVEYING MECHANISM Filed May 51, 1947 5 Sheets-Sheet 3 June 29, 1948. E. R. SABEL ET AL 2,444,170

PHOTOGRAPHIC PRINT coNvEYINe MECHANISM Filed May 31, 1947 r s Sheets-Sheet 4 June 29, 1948. sA ET AL 2,444,170

PHOTOGRAPHIC PRINT CONVEYING MECHANISM Filed May 31, 1947 5 Sheets-Sheet 5 Patented June 29, 1948 PHOTOGRAPHIC PRINT CONVEYING MECHANISM Edward It. Sahel and Frank ll. Galhrecht, Rochesassignors to ter, N. Y.,

The Haloid Company,

Rochester, N. Y., a corporation of New York Application May 31, 1947, Serial No. 751,592

12 Claims.

This invention relates to a photographic print conveying mechanism and has for its purpose to afford a practical and efiicient automatic mechanism for rapidly carrying sheets or prints from a developer tank through a, continuously operating feeding mechanism into a hypo-containing or fixing tank where the prints are released in a horizontal position below the liquid level in the tank.

Heretofore, the usual practice for transferring prints froma developing tank into a fixing tank has required a manual operation to depress the prints in the fixing liquid for thorough and intimate contact by pushing them from the top of the liquid downwardly, and it is a more particular purpose of the invention to afford mechanism for conveying the prints in horizontal position into the body of the fixing liquid beneath the surface thereof, and automatically releasing a print when it is entirely within the liquid, whereupon it floats to the surface to a position just under the print immediately thereabove, whereby each print is brought into thorough contact at all portions with the fixing liquid, and when a sufficient supply of prints is collected in the fixing tank, they can be easily removed by the operator for washing.

Another object of the invention is to afford a construction that permits of a completely automatic operation whereby prints can !be fed from a developer tank continuously and successively into a fixing tank, and. intermittently fed and released as required in the hypo solution when in a horizontal position in the fixing tank. A further purpose of the invention is to afford a conveying mechanism within a fixing tank that is automatically and intermittently operated to grip a print as the latter enters the fixing tank, then to convey the print until it assumes a completely horizontal position within the tank, and finally to release the print to permit its floating upwardly in the hypo solution underneath the mass of prints above.

An additional object of the invention is to afford a construction of the general character mentioned in which the feeding mechanism continuously operates to deliver prints from the developer tank to the fixing tank, and the conveying mechanism within the fixing tank is idle except when a print enters the fixing tank, whereupon the print automatically efiects a complete cycle of movement of the conveying mechanism which grips the print, conveys it to horizontal position within the fixing solution, and then re leases the print.

Another purpose of the invention is to afiord simple and efficient form of print-conveying and gripping means, including gripping devices that automatically engage and release a print at edetermined points, while movement of the grip ing devices and conveyor is governed by electrical means under the control of the print itself as it travels through the machine.

Still an additional object is to afford an arrangement of fixing tank, feeding means for eftesting movement of prints from the developer tank into the fixing tank, conveyor belts within the fixing tank, drive means for the feeding means and conveyor belts, and instrumentalities operated by the print as it travels into the fixing tank for efiecting movement of the con veyor belts through a cycle, following which the conveyor belts remain idle until another print enters the fixing tank, thus enabling continuous d fast processing of prints from a photocc, he or the like Without requiring atr h b ion from the operator for the fixing operation. other than to remove a mass of prints occasionally from the fixing tank when the latter has been filled to capacity.

To these and other ends, the invention consists in the construction and arrangement of parts iat nvill appear clearly from the following de scription when read in conjunction with the accompanying drawings, the novel features being pointed out in the claims following the specification.

In the drawings:

.E-ig, 1 is a vertical sectional view of a machine, partially laroken away, showing a preferred emlbooliment of the invention and illustrating the conveyor belts in idle position previously to the entrance of a print;

2 is a sectional view similar to Fig. 1, with parts omitted, and showing the position of a con-- veyor belt and gripping device after a print has engaged and moved the control member, causing the conveyor belt to he released and the gripping device to engage the forward edge of the print and carry it along on the conveyor belts;

Fig. 3 is a transverse vertical sectional view with the convey-or pelts held in idle position;

Fi na is a similar View showing the position of the parts after the stop devices have been elevated. to release the conveyor belts and sheetgripping devices;

5 is a vertical sectional View looking from right to left of Fig. 3 and showing the relation of the mechanism to the feeding means and developer tank of a photocopy machine;

Fig. 6 is a detail sectional View looking from right to left of Fig. 4 and illustrating the drive to the feeding rolls and conveyor belts within the fixing tank;

Fig. '7 is a sectional view through the fixing tank showing the relation of the conveyor belts and gripping devices, and the position of a print after its release from the conveyor belts;

Fig. 8 is a view in end elevation of the machine looking from left to right of Fig. 3;

Fig. 9 is an a portion of one of the conveyor belts and one of the sheet-gripping devices carried thereby, and

Fig. 10 is an enlarged detail sectional view on line Iii-40 of Fig. 9 looking in the direction indicated.

Referring more particularly to the drawings in which like reference numerals refer to the same parts throughout the several views, I designates a photographic fixing tank for containing a hypo solution, suitably mounted on supports 2 in adjacent relationship to a developer tank 3, see Fig. 5, from which prints are fed after developing to-the fixing tank I. 4 designates a print positioned in the focal plane of a photocopy camera for instance, to be fed downwardly, after exposure, by feed rolls 5 and cut off by the knife 6, whereupon the print is fed through a chute 1 and engaged by the feeding belts 8 which conduct the print downwardly into the developer tank, and thence upwardly over a bridge 9, to a point between the belts I0 which carry the print downwardly into the fixing tank and the liquid therein.

The belts in of the feeding mechanism are operated continuously by drive mechanism that will be described presently, and as prints are received from 'the developer tank, they are fed downwardly between the belts l ll into the fixing tank, whence they II in a manner that will now be explained. The feeding belts II] are spaced from each other, and the conveyor belts II are likewise spaced from each other, the feeding belts Ii] being preferably constructed of woven plastic or other suitable material while the conveyor ably constructed of rubber proper cooperation with the vices to be described later.

It will be observed that the upper feeding belt It] extends downwardly a less distance than the lower feeding belt ID, and when a sheet or print reaches the lower end of the upper feeding belt, it is deflected and guided by suitable means outwardly away from the lower feeding belt and around the lower end of the upper belt Ill toward the conveyor belts II, the forward edge of the print in the meantime having engaged and lifted a shoe I 2 of a control member located between the feeding belts l0 and in the path of the print as it is fed therethrough. The conveyor belts l l are normally stationary, and when the shoe [2 is elevated by the print, it acts to release the conveyor belts l l for movement and the conveyor belts thereupon grip the forward edge of the print by mechanism that will presently be described.

In order to grip a print, each conveyor belt is provided with two gripping devices arranged at points of the belt, as illustrated in Figs. '7, 9. and 10, each gripping device comprising a metal plate overlying the outer surface of the belt and including flanges l3 that extend through the body of the belt and are bent against the under surface thereof to hold the gripping device securely belts II are preferso as to effect the print-gripping deenlarged detail view in elevation of emerge onto conveyor belts travels and is flexed around as illustrated in Fig. l.

.ment causes the on the belt, while l4 designate opposite stop portions in the form of extensions projecting laterally beyond the ed'g'es of the belt and affording means whereby the belt is held against movement between successive cycles. l5 designates the gripping portion of the plate in the nature of a tongue lying against the belt to engage a print when disposed in parallelism therewith, as in Fig. 2, and occupying a position spaced from the adjacent part of the belt when the latter its supporting pulley, Thus in the idle position of the conveyor belts, when the stop portions I 4 are held by the stop devices to be described presently, the gripping portions or tongues |5-lie in a horizontal plane while the adjacent part of the conveyor belt extends around its supporting pulley and affords a recess or space between the belt and the gripping por tion [5 into which the forward edge of the advancing print moves as 'it leaves the feeding belts.

' As a print isfed downwardly into the fixing tank and travels around the lowerend of the upper belt In, it moves in between the tongue l5 of the gripping device and the adjacent surface of the belt, and the movement of the parts is so timed that just as the print occupies this position, the'conveyor belts are released and start to move forwardly at the same speed. as the advancing print, and such forward movegripping portions IE to engage the forward edge of the print in the manner shown in Fig. 2. This takes place immediately after the conveyor belts have started to move and as soon as the conveyor belts and gripping portions [5 have assumed parallel relative positions, the gripping. devices thus acting to hold the print on the conveyor belts and to carry it along with the conveyorbelts through the liquid in the fixing .tank until the entire print occupies a horizontal position in the tank, as illustrated in Fig; 7. When the gripping devices which hold the print reach the outer end of the tank, the gripping portions move away from the conveyorbelts as the belts travel around their supporting pulleys at the outer end of the tank, thus releasing the print which is then freeto float=upwardly in a horizontal position through the liquid to the surface or until it engages a print or prints already resting at the surface of the body of liquid.

The conveyor belts travel around pulleys l6 mounted on a driven shaft [1 at the inner end of the "tank, see Fig. 7, and around pulleys It! at the outer end of the liquid tank, said pulleys l8 'beingmounted on the shaft I9. The belts and gripping devices are shown in the normal position of rest as at the beginning of a cycle in Figs. 7 and 1, where it will be observed that the grippin iflportions I5 are separated from the belts as the latter are flexed around the adjacent pulleys 16, thus affording a space between the gripping portions l5 and the belts into which the forward edge of the print or sheet passes as it is fed by belts l9 onto the conveyor belts.

By the time a print reaches the position just described between the gripping portions I5 and the conveyor belts, the latter start to travel forwardly at the same speed as the print after having been released by the movement of the print or sheet, and thereupon the gripping devices assume the position illustrated in Fig. 2 and carry the print along until it reaches the outer end of the tank, where it is released as the belts travel around the pulleys l8 and the gripping portions are separated from the :adjacent surface of the 'belt.

'llh'e prints :are carried through the liquid and fixing tank by two or more conveyor belts if which are spaced from each other, the sheet being supported between the belts by the tracks or vertical walls 2! mounted on the bottom of the tan-k, and when-a print is released from the conveyor belts, it floats upwardly through the liquid to the surface thereof-or to a p-oint'in contact with the print immediately thereabove, and this operation is repeated whenever a print is conducted by the feeding mechanism from the developer tar-i k into the fixing 'tanlgno attention-on the part "of the operator being required other than to removea s'tack of prints from the fixing tank when a sufiicien't number have accumulated after a period of time. The conveyor belts are normally "idle with thegrippingdevices in the position illustrated in Figs. 1 and '7, there being two gripping "devices'spaced from each other at opposite points or each belt, and the feeding belts are r tained in'idl-e position after completion of a cycle by stop devices, the construction and operation of which will now be described in detail.

The stop devices comprise a pair of stop plates 22, see Fig. 4, pivotally mounted at 23 on the crossbar 26, supported at its ends on side walls 2-0 of "a supporting frame mounted in the tank i, and each stop plate includes bifurcated portions 25 that straddle a belt if in the manner shown in 3 in front of the stop portions it of the grip ping devices on the belt, so that when the stop plates 22 are in their lowered positions, :as shown in Fig. 3, the bifurcated portions 2% lie in the path of the stop portions i l and prevent movement of the belts. At the predetermined point in the movement of the print into the fixingtank, the stop plates 22 are lifted to the position shown in Fig. 4 to release the belts, and to effect this, each stop plate includes an upstandin'g arm 25 that is pivotally connected by an arm 21, while 28 indicates a link connecting the outer .a-rm'zfi .toa plunger 29 of a solenoid til. 3i designate lugs carried by the upper end of the stop spla'tes v '24! and adapted to engage the upper edge of the across-bar 2d and limit downward movement of the stop plates.

The solenoid Si] is controlled by a micro-switch of conventional construction indicated at The solenoid til is supported on a bracket 33 v nrcmnted upon the frame 34 of the machine and the micro-switch '32 is mounted on a plate that is :pivotally supported on a plate N, which 'is atta'ch'ed to the frameof the machine, the position 'of the tmicro-switch being adjustable by means of the adjusting screw 36 mounted on the fixed :plate 3:! and adjustably connected to an car 38 on the pivoted switch supporting plate which is pivoted to the plate 31 at 39 whereby the micro-switch can be set to exactly the proper position f'fior actuating the stop devices at the :critical instantwhen'theiprintor sheet reaches a positionfbetween the gripping devices and the belts.

M3 and desig-nate conductors leading to the solenoid and micro-switch respectively, while ides'ignates a conductor leading from the :solenoid to the switch, and 43 designates the movable arm of the micro-switch 32, tha't'is actuated to close thercircuit and operate the solenoid. The micro switch and arm '43 are'd'elicate, so as to be controlled by a paper print, and to effect this, the switchra'rm lii is engaged and operated by a rock. arm 44, :see Figs. 4 ends, mounted on a block $4.6 fixcii to a rock shaft "45 which is mounted at I its ends in bearings carried by the walls 20, and

carries a control member or rod l! that extends downwardly between adjacent feeding belts and terminates in the aforementioned shoe l2, see 5 Figs. 1 and 2, which normally occupies a lowered position as illustrated in l in the path of the print or sheet as it is fed downwardly into the fixing tank, the shoe l2 and control member bein elevated by the sheet and assuming the position illustrated in Fig. 2 as the print is fed thereunder and onto the conveyor belts.

The lower feeding belts iii extend to the bottom of the fixing tank, as shown in Figs. 1 and 5, whereas the upper feeding belts terminate at a point slightly under the top lap of the conveyor belts l i, and d8 designate deflecting guide walls adjacent to and between the belts for guiding the paper under and around the lower ends of the upper belts m and thence onto the conveyor belts l i, see Fig. 2, while "35 designate belt-engaging abutments secured to a cross-support 5 r d to the side pla es 29, the abutments 49 being located for engagement under the central tions of meeting laps of the belts If! to 2'5 effect stretching of the belts at this point and consequent tight engagement with the sheet or print it passes therethrough, so as to hold the wet paper web or sheet suificiently taut so that its forward edge will engage and lift the shoe !2 of the control member, to effect the necesoperation of the parts already described as sheet travels from the feeding mechanism the conveyor belts.

ced vertical walls 5! also fastened to the support iii and to which the guide walls fastened, and which support the portions w print beyond the feeding belts, while 56 gnate retaining belts acting to hold the print down against said walls 5|, see Fig. 3.

The upper feeding belts lfl are mounted on LUTS carried by the shafts 52 and 53 respecwhile the lower feeding belts are mounted a pulleys carried by shafts 5d and 55 respec tively, the entire assembly of feeding belts, pulleys and shafts 5-2, 53, 1M, 55 and H, and the stop devices, control member and rock shaft d6 being supported on the aforementioned side plates 25] supported within the tank and slotted at 5?, Figs. 2 and 6, to engage .a shaft 58 on which mounted a feed roller 58 engaging the roller mounted on shaft iii, the print being fed by rollers and 3% from the aforementioned bridge see 5, to the feeding mechanism which carries the print downwardly into the fixling tank.

The feeding belts 3 in the developer tank travel .-..cl pulleys i on shafts 63, 64 and reectively, and the several pulley shafts are en 'fr r the motor Eiii, see Figs. 5 and 7, which .1011 ill on a shaft which drives shaft from which the

shafts

64 and 83 are driven. To operate the aforementioned feeding and concr belts, the pinion 6'! engages and drives pinion 6E9 which engages gear 7 3, while the latter engages pinion H on shaft '58, and pinion ll engages and drives pinion l2, geared to pinion "1'3 on shaft 56, see 5, pinion 13 in turn en aging gear l lon shaft 52, thus driving the shafts and E l. Pinion '72 also drives an idler ion which engages idler gear T5, the latter .ging idler pinion "ll that engages pinion 6 which drives pinion E9 on shaft 55, on which ulleys for thelow'er feeding belts -I 0 are mounted. inion T19 engages an idler gear 80 which in turn drives the gear 8| mounted on the shaft I! that carries the pulleys l6 around which the conveyor belts ll travel.

Since the conveyor belts travel only intermittently when a print is fed to the fixing tank, whereas the shaft I! on which the pulleys l8 are mounted is traveling continuously, it is necessary to provide means for permitting the pulleys to ride freely on the shaft while the conveyor belts are held by the stop devices, and to engage the pulleys with the shaft I! for moving the pulleys when the conveyor belts are released, and to accomplish this, the pulleys l6 are freely rotatable on shaft H and engage against collars s2 fixed on the shaft, see Fig. 4, the pulleys it being held frictionally against said collars by means of friction collars or clutch elements ili'iactuated by springs 84 located between the friction clutch elements 83 and collars 85 fixed on the shaft. With this construction, when the conveyor belts are held by the stop devices 22, as shown in Fig. 3, the pulleys I6 remain stationary on the shaft H which slips within the pulleys, and when the conveyor belts are released, the pressure of the friction clutches 83 acting under the springs 85 is sufficient to cause the pulleys it to rotate with the shaft l1 and to move the conveyor belts through one cycle, or half the total length of the conveyor belt, until the stop portions of the opposite gripping device on each belt is engaged by the stop devices, it being understood that the stop plates are released and drop back into locking position after a print or sheet has passed beyond the shoe l2, permitting the control member to resume its normal position and release the switch arm to open the solenoid circuit. 86 designate vertical arms or uprights attached to the cross-support 24, acting to prevent prints, as they float upwardly in the liquid, from moving back over the stop plates and feeding belts.

With this construction, it is possible to process prints at a very fast rate as they come from a photocopy machine for instance, and to carry prints continuously and automatically from a developer tank to a fixing tank without attention on the part of the operator, the prints being fed successively into the liquid of the fixing tank in a horizontal plane and released at a point substantially below the level of the liquid, from which position each print floats upwardly until it strikes the print above, and when the body of liquid above the conveyor belts is substantially filled with prints, the operator can remove them. for washing. This necessitates only occasional effort on the part of the operator and eliminates the necessity for a hand operation in feeding prints into the fixing tank or of manipulating the prints while in the fixing tank by paddling or otherwise to insure proper immersing, since the mechanism effects complete and thorough contact of every portion of a print with the fixing liquid, clue to the fact that the print enters below the surface of the body of fixing liquid and when released, floats slowly upwardly toward the surface of the liquid.

While the invention has been described in connection with a preferred embodiment, it is not restricted to the details herein disclosed, and this application is intended to cover such modifications or changes as may come within the scope of the following claims.

We claim:

1. The combination with intermittently moving conveyor belts and driving means for the conveyor belts, of sheet-gripping devices carried by the conveyor belts, each gripping device being fixed at one end to a belt and including a. gripping portion which lies parallel to and against the belt when the adjacent portion of the belt is straight and spaced from the belt when said adjacent portion is curved away from the gripping portion, and feeding means comprising opposed belts coacting to conduct a sheet positioned therebetween to a position with its forward edge between the conveyor belts and said gripping portions when the belts are stationary, the gripping portions being automatically moved into contact with the belts to grip the sheet after the belts start to move and away from the belts at a predetermined point to release the sheet, said sheet-gripping and releasing operations being effected as the belts assume a curved position upon traveling around pulleys to thereby grip and release the sheets successively.

2. The combination with intermittently moving conveyor belts and driving means for the conveyor belts, of sheet-gripping devices carried by the conveyor belts, each gripping device being fixed at one end to a belt and including a gripping portion which lies parallel to and against the belt when the adjacent portion of the belt is straight and spaced from the belt when said adjacent portion is curved away from the gripping portion, feeding means comprising opposed belts coacting to conduct a sheet positioned therebetween to a position with its forward edge between the conveyor belts and said gripping portions when the belts are stationary, and instrumentalities controlled by the fed sheet and acting to release and permit movement of the conveyor "belts and thus effect said relative movement between the belts and said gripping portions, the gripping devices being automatically moved in relation to the belts at a predetermined point to release the sheet.

3. The combination with intermittently moving conveyor belts and driving means for the conveyor belts, of sheet-gripping devices carried by the conveyor belts, each gripping device being fixed at one end to a belt and including a gripping portion movable relatively toward and from the belt, feeding means for conducting a sheet to a position with its forward edge between the conveyor belts and said gripping portions, stop devices engaging the gripping devices on the belts and acting to hold the belts against movement, and instrumentalities controlled by the fed sheet acting to move the stop devices to release the belts and to thereby permit said relative movement between the conveyor belts and gripping portions to grip the sheet, the gripping portions being automatically moved in relation to the belts to release the sheet at a predetermined point.

4. The combination with intermittently moving conveyor belts and driving means for the conveyor belts, of sheet-gripping devices carried by the conveyor belts, each gripping device being fixed at one end to a belt and including a gripping portion movable relatively toward and from the belt, feeding means for conducting a sheet to a position with its forward edge between the conveyor belts and said gripping portions, friction clutches between the driving means and the conveyor belts, stop devices engageable with the sheet-gripping devices, and instrumentalities controlled by the fed sheet acting to move said stop devices to release the conveyor belts and to thereby permit said relative movement between I .9 the conveyor belts and said gripping portions to grip the'sheet, the gripping portions being automatically moved in relation to the belts at a predetermined point to release the sheet.

5. The combination with intermittently moving conveyor belts, inner and outer pulleys around which said belts travel, and driving means for said pulleys, of sheet-gripping devices carried by the belts, each gripping device being fastened at one end to its belt and having a gripping portion free from the belt and separable therefrom when the belt travels around a pulley, stop-devices engagin the gripping devices and acting to hold the belts in position with gripping devices at the inner pulleys and their gripping portions spaced from the belts to permit positioning the forward edge ofa sheet between the belts and said gripping portions, feeding means for conducting a sheet to a position with its forward edge between the belts and said gripping portions, and instrumentalities controlled by the fed sheet and acting to move said step devices to release the conveyor belts for movement, the sheet being gripped and-carried by the conveyor belts and automatically released when the grip-- ping devices reach the outer pulleys and the adjacent belt portions travel around said pulleys and move away from said gripping portions.

6. The combination with intermittently mov ing conveyor belts, inner and outer pulleys around which said belts travel, and driving means for said pulleys, of sheet-gripping devices carried by the belts, each gripping device being fastened at one end to its belt and having a grip ping portion free from the belt and separable therefrom when, the belt travels around a pulley, friction clutches between said driving means and said pulleys,.stop devices engaging the gripping devices and acting to hold the belts with gripping devices at the inner pulleys and their gripping portions spaced from the belts to permit '90- sitioning the forward edge of a sheet between the belts and said gripping portions, feeding means for conducting a sheet 'to a position with its forward edge between the belts and said gripping portions, and instrumentalities controlled by the fed sheet and acting to move said stop devices to release the conveyor belts for movement, the sheet being gripped and carried by the conveyor belts and automatically released when the gripping devices reach the outer pulleys and the adjacent belt portions travel around said pulleys and move away from the gripping portions.

7. The combination with conveyor belts, inner and outer pulleys around which said belts travel, driving means for said pulleys, and friction clutches between said driving means and pulleys, of sheet-gripping devices carried by the conveyor belts, each gripping device including a plate fastened at one end to the belt, stop portions extending laterally beyond the edges of the belt, and a gripping portion overlying and separable from the belt when the latter is flexed away from the gripping portion, stop devices engaging said stop portions and holding the belts in position with gripping devices at the inner pulleys and their gripping portions separated from the belts to permit positioning the forward edge of a sheet between the belts and said gripping portions, feeding means for conducting a sheet to a position with its forward edge between the belts and said gripping portions, and instrumentalities controlled by the fed sheet and acting to move said stop devices and release the belts to permit their movement to grip and convey the sheet, the sheet being automatically released when the gripping devices reach the outer pulleys and the adjacent portions of the belts travel around said outer pulleys and move away from said gripping portions and the gripping devices being engaged by said stop devices to stop movement of the belts after release of the sheet.

8. The combination with a photographic fixing tank and conveyor belts located beneath the level of liquid in the tank and intermittently operating to conduct a sheet horizontally in said tank below the liquid level therein, of feeding means comprising opposed belts extending above the level of liquid in the tank and coasting to conduct a sheet positioned therebetween downwardly into said tank and onto said conveyor belts, each conveyor belt traveling around inner and outer pulleys and having a pair of gripping devices attached thereto at opposite points on the belt, drive means for the pulleys, friction clutches between said drive means and the pulleys, each gripping device being fastened at one end to the belt and having stop portions extending laterally beyond the edges of the belt and a gripping portion overlying and separable from the belt when the latter is flexed around a pulley, stop devices engaging said stop portions and holding the belts in position with gripping devices at the inner pulleys and their gripping portions separated from the belts to permit positioning the forward edge of a sheet between the belts and said gripping portions, and instrumentalities controlled by a fed sheet acting to move said stop devices and release the conveyor belts to grip and carry the sheet, the sheet being automatically released when the gripping portions reach the outer pulleys and the stop devices being automatically reengaged with said stop portions.

9. Ihe combination with a photographic fixing tank and conveyor belts located beneath the level of liquid in the tank and intermittently operating to conduct a sheet horizontally in said tank below the liquid level therein, of feeding means comprising opposed belts extending above the level of liquid in the tank and coacting to conduct a sheet positioned therebetween downwardly into said tank and onto said conveyor belts, each conveyor belt traveling around inner and outer pulleys and having a pair of gripping devices attached thereto at opposite points on the belt, driving means for the pulleys, friction clutches between said drive means and the pulleys, each gripping device being fastened at one end to the belt and having stop portions extend ing laterally beyond the edges of the belt and a gripping portion overlying and separable from the belt when the latter is flexed around a pulley, stop devices engaging said stop portions and holding the belts in position with gripping devices at the inner pulleys and their gripping portions separated from the belts to permit positioning the forward edge of a sheet between the belts and said gripping portions, a solenoid plunger connected to said stop devices, a micro-switch controlling said solenoid, a rock arm engaging said micro-switch, a rock shaft on which said arm is mounted, and a control member mounted on said rock shaft and including a shoe lying in the path of a sheet as it is fed to the conveyor belts.

10. The combination with a photographic fixing tank and conveyor belts located beneath the level of liquid in the tank and intermittently operating to conduct a sheet horizontally in said tank below the liquid level therein, of feeding means comprising opposed belts extending above the level of liquid in the tank and coacting to conduct a sheet positioned therebetween downwardly into said tank and onto said conveyor belts, inner and outer pulleys for the conveyor belts, drive means for the pulleys, gripping devices on the conveyor belts including gripping portions separable from the belts when the belts travel around the pulleys and flex away from said gripping portions, movable stop devices engageable with the belts, a solenoid connected to said stop devices, a micro-switch controlling said solenoid, a rock arm engaging said micro-switch, a rock shaft on which said arm is mounted, and a control member mounted on the rock shaft and including a shoe lying in the path of a sheet as it is fed to the conveyor belts.

11. The combination with a photographic fixing tank and conveyor belts located beneath the level of liquid in the tank and intermittently operating to conduct a sheet horizontally in said tank below the liquid level therein, of feeding means comprising opposed belts extending above the level of liquid in the tank and coacting to conduct a sheet positioned therebetween downwardly into said tank and onto said conveyor belts, each of said conveyor belts traveling around inner and outer pulleys and having a pair of gripping devices attached thereto at opposite points of the belt, drive means for said pulleys, friction clutches between the drive means and pulleys, each gripping device being fastened at one end to its belt and having stop portions extending laterally beyond the edges of the belt and a gripping portion overlying and separable from the belt when the latter is flexed around a pulley, stop devices comprising pivotally mounted plates having bifurcated portions which straddle the belt and engage said stop portions, a solenoid plunger connected to said stop devices, a micro-switch controlilng said solenoid, a rock arm engaging said micro-switch, a rock shaft on which said rock arm is mounted, and a control member mounted on said rock shaft and including a shoe lying in the path of a sheet as it is fed to the conveyor belts.

12.v The combination with a photographic fixing tank and conveyor belts located beneath the 12 level of liquid in the tank and intermittently operating to conduct a sheet horizontally in said tank below the liquid level therein, oi feeding means comprising opposed belts extending above the level of liquid in the tank and coacting to conduct a sheet positioned therebetween downwardly into said tank and onto said conveyor belts, inner and outer pulleys for the conveyor belts and drive means for said pulleys, friction clutches between said drive means and pulleys, sheet-gripping devices on the conveyor belts including gripping portions movable relatively away from the belts, stop devices engageable with the 'belts, a solenoid connected to said stop devices, a micro-switch controlling said solenoid, and a control member operatively connected to the micro-switch and including a shoe lying in the path of a sheet as it is fed to the conveyor belts acting to release the belts to carry the sheet through the tank, said gripping portions being automatically engaged with and disengaged from the sheet at the beginning and end of each cycle as they leave the inner pulleys and reach the outer pulleys respectively.

EDWARD R. SABEL. FRANK I. GALBRECHT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 526,103 Evla Sept. 18, 1894 847,379 Smiley Mar. 19, 1907 1,057,636 Grauer Apr. 1, 1913 1,250,478 McKenzie Dec. 18, 1917 1,261,926 Greene Apr. 9, 1918 1,328,305 Sussman Jan. 20, 1920 1,848,102 Blair e Mar. 8, 1932 1,934,578 Williams Nov. 7, 1933 2,015,187 Mayer Sept. 24, 1935 2,154,585 Samandji Apr. 18, 1939 2,177,460 Renz "a Oct. 24, 1939 FOREIGN PATENTS Number Country Date 663,185 Germany July 30, 1938