GB2043490A - Film processor - Google Patents

Abstract

A dip-and-dunk film processor comprises a pair of sprocket wheels (1, 2) located one above the other, an endless chain (3) passing around both wheels, and a single-speed electric motor driving at least one of the wheels. A pair of bars (5) are mounted for reciprocating vertical movement, and a second pair of bars (7) extends parallel to the first pair of bars. A lever (8) is pivotally connected at one of its ends to the bars (5), pivotally connected at a point intermediate its ends to the bars (7) and pivotally connected at its other end to the endless chain (3). A carrier (12) is provided on the bars (7) for carrying a film- receiving hanger (13), whereby movement of the endless chain (3) causes the bars (7) to reciprocate both vertically and horizontally and move the hangars (13) from one bath (14) to the next. <IMAGE>

Description

SPECIFICATION Film processor This invention relates to a film processor.

Processors are known which are of the socalled dip-and-dunk type. In such processors hangers carrying the films to be processed are dipped in a succession of baths, the raising and lowering of the hangers which is necessary for this being carried out by mechanical means. The successive baths are located side by side which means that a hanger being transferred from one bath to the next must successively be lifted from the first bath, moved sideways to locate it over the second bath, and then lowered into that second bath.

In a known dip-and-dunk machine lifting and lowering of the hangers and their sideways movement are produced by a pair of bars which are secured to an endless chain passing around two sprocket wheels located one above the other and from which the hangers are freely suspended. One of the sprocket wheels is driven by an electrical motor. When the motor is in operation the bars are caused to move up and down and also to reciprocate laterally. By appropriate means this lateral movement is used to cause movement of the hangers in a single lateral direction in order to move them from one bath to the next.

It is desirable to transfer the films being processed from one bath to the nxt as quickly as possible. The desirability of this arises from the need to reduce the amount of time for which the films are exposed to the air and also the need to reduce the difference in the times for which different portions of the films being processed are in each bath. It will be appreciated that portions of the films nearer the lower end of the hanger are in the bath for longer than portions of the films nearer the upper end of the hanger, and this difference is accentuated if the films are moved into and out of the baths only slowly. However, as noted above, the hangers are suspended freely from the above mentioned bars while they are being transferred from one bath to the next.If the hangers are moved too quickly during the portion of time in which they are being moved laterally this causes the hangers to swing, and this can give rise to serious difficulties, such as, for example, the hanger entering the wrong bath when it is lowered or becoming jammed against the dividing wall between two adjacent baths. In known machines, therefore, the electric motor mentioned above is a two-speed motor, its slower speed being used while the hangers are moving laterally, and its faster speed being used for the rest of the time. However, the use of a two-speed motor does itself give rise to problems, such motors and their associated control circuitry being expensive and inclined to be unreliable.

It might be thought that the problem could be dealt with by suspending the hangers rigidly rather than allowing them freedom of pivotal movement. In practice, however, no satisfactory way of fixing the hangers rigidly has been found. Nor is it possible to overcome the problems simply by making the baths narrower, thereby reducing the distance through which the hangers have to be moved laterally. An adequate clearance must be left between the films being processed and the walls of the baths.

According to the present invention there is provided a film processor comprising a pair of wheels located one above the other; an endless drive member passing around both wheels; means for driving at least one of the wheels; a first bar arrangement mounted for reciprocating vertical movement; a second bar arrangement extending parallel to the first bar arrangement; a lever pivotally connected at one of its ends to the said first bar arrangement, pivotally connected at a point intermediate its ends to the second bar arrangement and pivotally connected at its other end to the said endless drive member; and means on the said second bar arrangement for carrying a film-receiving hanger, whereby movement of the endless drive member causes the second bar arrangement to reciprocate both vertically and horizontally.

Part of one embodiment of the present invention is shown in the accompanying drawing. This shows a pair of sprocket wheels 1 and 2 around which an endless chain 3 passes. At least one of the sprocket wheels is driven by a single-speed electric motor (not shown). A second pair of sprocket wheels and a corresponding drive chain are located to the right of those illustrated, the construction being basically symmetrical about the vertical plane 4 indicated. Two upper bars 5 are mounted for sliding vertical movement on an upright 6 (only one of the bars is shown, the other bar being behind that illustrated). Two lower bars 7 are connected to the bars 5 by a lever 8 which is connected by a pivot 9 to the bars 5, by a pivot 10 to the bars 7, and by a pivotal connecting member 11 to the chain 3.

The bars 7 each have a plurality of carriers 12, two of which are shown in the drawing, and a film carrying hanger 1 3 deepens freely from one of the carriers 1 2. A processing installation comprising a plurality of baths 14 is positioned below the apparatus just described.

Operation of the processor is as follows. As the sprocket wheels rotate the chain 3 moves so that the pivotal connector 11 travels in a downward direction. This in turn causes the bars 5 and 7 to move downwards, the bars 7 carrying with them the hanger 1 3. When the hanger 1 3 has descended a sufficient distance the films thereon enter a respective one of the baths 1 4. As the hanger 1 3 continues to travel downwardly the upper end thereof, which hitherto has been resting on a respective carrier 12, engages a fixed carrier (not shown) positioned adjacent the baths, and further downward movement of the bar 7 takes the carrier 1 2 out of contact with the hanger 1 3. At this point in the operation the motor is automatically stopped and the films on the frame are left in the bath for a predetermined length of time. When this time has eiapsed the motor is restarted and the pivotal connector 11 passes around the lower sprocket wheel 2. Because of the presence of the lever 8 the bars 7 are caused to move laterally in a leftward direction. This brings another carrier 1 2 positioned rightwardly of the carriers illustrated below the upper portion of the hanger 1 3 and continued movement of the chain 3 causes this further carrier 1 2 to engage the hanger 1 3 and lift it upwardly and out of the bath.When the pivotal connector 11 reaches the upper sprocket wheel 1 it travels around that wheel and thus causes the bars 7 with its carriers 1 2 and the hanger 1 3 to move rightwardly. However, it should be noted that the amount of rightward movement of the bar 7 is less than the diameter of the sprocket wheel 1, the difference depending on the lever ratio of the lever 8. The hanger 1 3 is then lowered into the next bath, and this process is repeated until the frame with the films thereon has entered each of the baths in turn.

Because of the presence of the lever 8 the size of sprocket wheels necessary to produce a given translational movement between one bath and the next is larger than in known constructions. It follows from this that the speed of travel upwardly and downwardly is higher than in known constructions, thus reducing the amount of time for which the films are in the air between baths and also reducing the difference in residence times in the baths of the various parts of the films.

Claims (7)

1. A film processor comprising a pair of wheels located one above the other; an endless drive member passing around both wheels; means for driving at least one of the wheels; a first bar arrangement mounted for reciprocating vertical movement; a second bar arrangement extending parallel to the first bar arrangement; a lever pivotally connected at a first point to the said first bar arrangement, pivotally connected at a second point to the said endless drive member and pivotally connected at a third point intermediate the said first and second points to the second bar arrangement; and carrier means on the said second bar arrangement for carrying a filmreceiving hanger, whereby movement of the endless drive member causes the second bar arrangement to reciprocate both vertically and horizontally.

2. A film processor according to claim 1, wherein the said first and second points are at opposite ends of the lever.

3. A film processor according to either preceding claim, comprising a plurality of baths arranged side by side, the said hanger being arranged to dip a film successively into each of the baths.

4. A film processor according to claim 3, comprising a plurality of stationary carrier means arranged respectively above each of the said baths, the first mentioned carrier means being arranged to deposit the said hanger in a stationary carrier means during downward travel of the said hanger and remove the said hanger from the stationary carrier means during upward travel of the said hanger.

5. A film processor according to any preceding claim, wherein the endless drive member is a chain and the said wheels are sprocket wheels.

6. A film processor according to any preceding claim, wherein the said drive means is a single speed electric motor.

7. A film processor substantially as herein described with reference to the accompanying drawing.