US3246823A

US3246823A - Transport mechanism

Info

Publication number: US3246823A
Application number: US288220A
Authority: US
Inventors: Einar W Jensen
Original assignee: Eastman Kodak Co
Current assignee: Eastman Kodak Co
Priority date: 1963-06-17
Filing date: 1963-06-17
Publication date: 1966-04-19
Anticipated expiration: 1983-04-19
Also published as: GB1072782A

Description

April 19, 1966 E. w. JENSEN TRANSPORT MECHANISM Filed June 17, 1963 m m M W R A w E WWW Y B A TTOR/VEYS United States Patent 3,246,823 TRANSPORT MECHANISM Einar W. Jensen, Rochester, N.Y., assignor to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey Filed June 17, 1963, Ser. No. 288,220 8 Claims. (Cl. 226188) This invention relates to a transport mechanism and, more particularly, to a transport arrangement operable to convey with equal facility strip films or sheet material both subject to length variation considerations.

. In transport mechanisms for self-threading and transporting flexible material such as photographic film or paper through a processing solution, the material being processed expands in all directions. Since there is no opportunity for increasing the spacing between the transport mechanisms, in transport mechanisms of the type in which i the material is interposed between guide and driving rollers of predetermined spaced intervals, slack will tend to develop in the material as it expands. In the case of mating guide rollers, this slack'tends to be detrimental in that the transported material will tend to weave from side to side. Such weaving from time to time will result in creases or mistracking and thereby damage or loss of the film material. The developing of slack in transported flexible material is eliminated in the present invention by providing a continuous, yet flexible drive arrangement in turn-around portions ofthe equipment. T

One of the primary objects of the present invention is to provide an improved transport mechanism for conveying flexible material oftwo substantially different types, one being continuous webbing and the other being arelatively short sheet material.

A more specific object of this invention is to provide a simple andreliable transport mechanism operable by a soft,over-driving clutch "such that a minimum speed is assured, but the speed automatically increases'to match the speed of a webbing'being transported.

-In accordancewith 'one embodiment of myinvention, a -plurality of co-operating rollers transport flexible material at a constant predetermined velocity-to a master roller assembly arranged to'change the line of travel of the material. Because of expansion problems, the master roller is spaced apart from a pluralitycf peripheral guide rollers, which are driven at a speed no less than that of the co-operating rollers. The master roller is, however, driven at a lower speed by a unidirectional clutch which allows the flexible material to increase the speed of the master roller should the expansion character thereof so dictate.

' The 'subiect' matter which is'regarded as my invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. The invention, however, as to its organization and operation together with further objects and advantages thereof, will best be understood by reference to the following description taken in connection with the accompanyingdrawing in which: FIG; 1 is a schematic view partially in cross-section of atransport mechanism in accordance with the present invention; 1 i 1 Y a FIG. 2 is an enlarged detail view illustrating the present invention;'and

FIG. 3 is a cross-sectional view taken along the line 3-3 of FIG. 2. t g Referring now to the drawing, wherein like numbers referto similar parts, I have illustrated in FIG. 1 a wet portion of a'processing equipment including at least three separate tanks 10, 1-1 and 12 which contain fluids such as developer, stop bath and fixer. Within these tanks and over the top of the spacing therebetween, I have provided a plurality of rollers drivable by a speed-regulated motor "ice 14. Transport rollers within each of the tanks may be coupled to driving

gears

16 and 17 by a driving means such as a chain 18 which engages a sprocket on one end of each of therollers 20 within the tanks to drive substantially all of the rollers so that they have equal and constant surface speeds. Equal surface velocities are attainable, by way of example, when the sprocket drives have an effective diameter equal to the surface diameter of the rollers themselves.

As is shown more clearly in FIG. 2, I prefer that the vertical transport rollers 20 be of substantially identical diameters to simplify the driving ratios. However, I have found that the turn-around central or master roller 22 should be of a substantially larger diameter to convey various sheets of flexible material, such as

film sheets

24, 25 and 26 from one line of co-operating transport rollers 24) to a next Without excessive bending of thefiexible material.

As is explained in some detail in the U.S. Patent No. 3,072,310, issued in the name of Charles J. Kunz, January 8, 1963, and assigned to the assignee of the present invention, the flexible material passes between the rollers 20, being guided by impingement upon and engagement on the surfaces thereof during its threading and transport through the solution in the tanks. Also, as explained in that patent, turn-around self-threading of the flexible material is accomplished by the master roller 22 and spacedapart smaller rollers 28 co-operating with a pair of guide shoes 29 which divert the sheets laterally of their line of motion so that they follow the curvature of the master roller 22. In a preferred embodiment, each of the rollers 28 are grear driven by the master roller 22 to have surfacevelocities no less than that of the rollers 20. p v

. Also in accordance with one particular embodiment of the present invention, an additional pair of rollers 30 is provided to assist in the guiding of the film sheets as they leave a slightly enlarged roller 32 which changes the direction of the sheets 2426 so that they are easily conveyed around the turn-around mechanism. Because of spacing problems, I prefer to drive the pair' of rollers 3tlby a pair of belts 33 driven by the rollers 28. The drive ratios are selected so that the surface velocities of the nearest rollmaster roller 22, to facilitate handling both continuous webs of flexible material such as 50 feet or more, and short sheets 26 of 5 inches or less. If the masterroller 22 is positively driven at the same surface velocity as the rollers 20, the dimensional instability of continuous Webbing filmcauses considerable build-up of tension in the region of the turn-around. This problem makes most difficult the transport of continuous webbing by a posi-- tive drive. A roller arrangement which overcomes this problem .by removing drive of the master roller 22 presents a serious problem of stoppage of these rollers when one attempts to self-thread therethrough film sheets having a length less than about 5 inches. Such a film sheet tends to pass only part way around the enlarged master roller 22, whereupon the roller 22 stops until a next sheet arrives to drive it. The resulting overlapping of sheets tends to cause serious damage to'partially developed films. v

In accordance with the present invention, I have provided a driving sprocket gear 34 shown (partially in phantom in FIG. 2) in FIG. 3 having a slightly larger eflective diameter than that of the master roller 22. Thus, the velocity of the chain 18 driving the sprocket gear 34 is slightly (about 2%) greater than the surface velocity of the master roller 22. However, the

rollers

28 and 30 are driven at surface velocities greater than that of the roller 22. Such an arrangement allows the dimensional instability of elongated film materials to be compensated for by the slightly reduced surface speed. If no reduction in velocity is called for by the exigencies of a particular film strip, the outer rollers 28 will drive the film at full speed.

The driving coupling between the sprocket gear 34 and the master roller 22 is a unidirectional clutch 36 arranged so that it provides a soft overdrive feature. As a result, when continuous Webbing engages the surface of the master roller 22, it may drive this surface at velocities substantially equal to the surface velocities of the rollers 20, whereby the driving coupling of the clutch 36 by the sprocket gear 34 and the roller 22 is disengaged. On the other hand, when the film sheets such as 26 pass through the region of the enlarged master roller 22, they will be driven along the desired transport path by engagement of the unidirectional clutch 36 so that stoppages as set forth above may not occur.

Thus, the chain 18 and the sprocket gear 34 tend to underdrive the master roller 22, and the longer sheets or Webs of flexible material (films 24) overdrive the overrunning clutch 36 to surface speed of the master roller 22 as great as that of the rollers 20.

While I have shown and described particular embodiments of the present invention, other modifications may occur to those skilled in this art. I intend, therefore, to have the appended claims cover all modifications which fall Within the true spirit and scope of my invention.

I claim:

1. In a conveyor arrangement for transporting and guiding at a predetermined lineal velocity a flexible material subject to dimensional instability considerations, a transport mechanism comprising:

a master roller;

a drive means for assuring a peripheral surface velocity of said master roller only slightly less than the predetermined lineal velocity of the flexible material;

a plurality of guide means spaced apart from and disposed around said master roller for guiding the flex ible material therearound; and

a unidirectional clutch coupling said master roller to said drive means so that when the flexible material tends to travel therearound at velocities less than the driven velocity, said clutch drives the flexible material, and when the flexible material continues to travel at the predetermined velocity, said clutch slips.

2. A transport mechanism as set forth in claim 1 wherein the drive means includes a chain and a sprocket with said chain having substantially the same velocity as the flexible material approaching said master roller, and said sprocket has an eifective diameter about 2% greater than that of said master roller.

3. In a conveyor arrangement for transporting and guiding at a predetermined lineal velocity a flexible material subject to dimensional instability considerations, a transport mechanism comprising:

a master roller;

a drive means for assuring a peripheral surface velocity of said masterroller only slightly less than the predetermiend lineal velocity of the flexible material;

a plurality of guide means including subservient rollers spaced apart from and disposed around said master roller for guiding the flexible material therearound;

a unidirectional clutch coupling said master roller to said drive means so that when the flexible material tends to travel therearound at velocities less than 4- the driven velocity, said clutch drives the flexible material, and when the flexible material continues to travel at the predetermined velocity, said clutch slips; and

means for driving said subservient rollers at surface velocities greater than that of said master roller.

4. A transport mechanism as set forth in claim 3 wherein said driving means of said subservient rollers includes gearing having gear ratios such that the surface velocity of said subservient rollers is no less than the predetermined lineal velocity.

5. A transport mechanism for a Web or sheets of flexible material having the property of expanding during transport, comprising:

a rotatable master roller having a peripheral surface drivable to transport the material;

a plurality of guide rollers disposed around the periphery of said master roller and spaced apart therefrom;

drive means for driving said master roller to have a surface velocity slightly less than the velocity of the flexible material as it approaches said master roller; and

an overrunning clutch coupling said drive means to said master roller only when the flexible material is not driving said master roller at a speed greater than that developed by said drive means.

6. A transport mechanism as defined in claim 5 wherein said guide rollers are drivably coupled to said master roller by gearing having ratios so that the surface velocity of said guide rollers is equal to the velocity of the flexible material when said drive means is eifectuating rotation of said master roller.

7. A transport mechanism for a web or sheets of flexible material having the property of expanding during transport, comprising:

a plurality of first guide rollers disposed around the periphery of said master roller and spaced apart therefrom;

a plurality of drive rollers positioned to present the material to said master roller and receive it therefrom with a main portion thereof defining parallel paths of the flexible material which are spaced apart less than the effective diameter of said master roller and including roller means adjacent to said master roller for expanding the paths of the flexible material to engage the periphery of said master roller;

an over-running clutch coupling said drive means to said master roller only when the flexible material is not driving said master roller at a speed greater than that developed by said drive means.

8. A transport mechanism as defined in claim 7 hav ing other guide rollers positioned between said master roller and said roller means to guide the flexible material therebetween said other guide rollers being drivably coupled to said first guide rollers to have a surface velocity equal to that of said first guide rollers.

References Cited by the Examiner UNITED STATES PATENTS 2,167,357 7/1939 George 226--156 X 2,966,746 1/1961 Mellbin 2261l9 X 3,072,310 1/1963 Kunz 226188 ROBERT B. REEVES, Primary Examiner.

C. A. AOUSSAT, Assistant Examiner.

Claims

1. IN A CONVEYOR ARRANGEMENT FOR TRANSPORTING AND GUIDING AT A PREDETERMINED LINEAL VELOCITY A FLEXIBLE MATERIAL SUBJECT TO DIMENSIONAL INSTABILITY CONSIDERATIONS, A TRANSPORT MECHANISM COMPRISING: A MASTER ROLLER; A DRIVE MEANS FOR ASSURING A PERIPHERAL SURFACE VELOCITY OF SAID MASTER ROLLER ONLY SLIGHTLY LESS THAN THE PREDETERMINED LINEAL VELOCITY OF THE FLEXIBLE MATERIAL; A PLURALITY OF GUIDE MEANS SPACED APART FROM AND DISPOSED AROUND SAID MASTER ROLLER FOR GUIDING THE FLEXIBLE MATERIAL THEREAROUND; AND A UNIDIRECTIONAL CLUTCH COUPLING SAID MASTER ROLLER TO SAID DRIVE MEANS SO THAT WHEN THE FLEXIBLE MATERIAL TENDS TO TRAVEL THEREAROUND AT VELOCITIES LESS THAN THE DRIVEN VELOCITY, SAID CLUTCH DRIVES THE FLEXIBLE MATERIAL, AND WHEN THE FLEXIBLE MATERIAL CONTINUES TO TRAVEL AT THE PREDETERMINED VELOCITY, SAID CLUTCH SLIPS.