US2693138A

US2693138A - Daylight developing tank for roll films having protective paper strips

Info

Publication number: US2693138A
Application number: US219365A
Authority: US
Inventors: Lesjak Michael
Original assignee: Individual
Current assignee: Individual
Priority date: 1950-05-11
Filing date: 1951-04-05
Publication date: 1954-11-02
Anticipated expiration: 1971-11-02

Description

Nov. 2, 1954 M. LE DAYLIGHT DEVELOPING HAVING PROTECTIVE PAPER il 5, 195

iled Apr SJAK TANK FOR ROL STRI l ILMS HIS ATTORN EYS United States Patent 0 DAYLKGHT DEVELOPING TANK FOR ROLL FILMS HAVDIG PROTECTIVE PAPER STRIPS Michael Lesjalr, Ichenhausen, Germany Application April 5, 1951, Serial No. 219,365

Citrims priority, application Germany May 11, 1950 7 Claims. (Cl. 95-0.5)

My present invention relates to a daylight developing tank for roll films having protective paper strips. More particularly, it relates to such a tank wherein, after separation of the protective paper strip, the roll film is drawn into spiral grooves on the flanges of a developing spool by means of a clamp atfixed to a pull-in band.

Daylight developing tanks of the above mentioned type have long been known and are described, for example, in the U. S. Patent No. 2,082,962. When treating roll films having protective paper strips in such apparatus, the film could not be pulled into the developing container directly from the film spool compartment, since the protective paper strip first had to be removed. It was necessary to provide a second film compartment located parallel to the axis of the film spool compartment, into which the roll film was unwound upon pulling out of the protective paper strip. Before the film could be drawn out of the second film compartment by means of the pull-in band, it was necessary to seal that compartment against the entrance of light, while leaving the end of the film exposed, by some suitable means, then to open the cover of the developing tank, afiix the clamp on the pull-in band to the protruding end of the film, close the cover of the developing tank and finally, open the light sealing means for the second film compartment.

The main object of my invention is to simplify such apparatus and to eliminate the tedious procedure described above. In accordance with my invention the clamp on the pull-in band is so arranged that the end of the film automatically enters the jaws of the clamp and is grasped thereby, when pulling out the protective paper strip. The introduction and treatment of the film in the developing tank may be carried out in full daylight. For this purpose the clamp is amxed at the film spool compartment in such a manner as to be releasable from outside the tank. This releasable attachment preferably is obtained by means of a bowed metal rod that is arranged parallel to the axis of the film spool compartment and whose bowed-out portion, when swung in one direction, presses the clamp against the film spool compartment and holds it there, and when swung in the other direction, releases it. A projection on the clamp serves as the bearing surface for the bowed-out portion of the metal rod. This projection is located on the outside of the lower jaw of the clamp. In order to hold the clamp in position at the opening of the film spool compartment, the handle used to swing the bowed metal rod may be locked. To insure a certain entrance of the beginning of the film between the jaws of the clamp, the lower jaw of the clamp, that rests upon the top edge of the partition between the film spool compartment and the developing container, is provided with a stripoif plate which bears resiliently against the circumference of the roll film spool.

Means are provided in my improved apparatus whereby the clamp on the pull-in band may be closed from the outside. Such means may, for example, consist of a resilient peg passing through the cover of the tank, whose lower end, when depressed against the action of a spring, touches the upper jaw of the clamp and upon further depression closes the clamp. Instead of such a resilient peg one may also employ a bowed rod whose bowed portion upon being swung by means of an outside handle bears against the upper clamp jaw and pushes it down to close the clamp.

In order to guide the protective paper strip as it is 2,693,138 Patented Nov. 2, 1954 pulled ofi from the roll film spool, I provide a hinged guide plate above the film spool compartment, that forms a slit with the cover of the tank, through which the protective paper strip is withdrawn. This hinged guide plate also serves to prevent loosening of the windings of the roll film, because when closed it rests upon the outermost film winding under the influence of a spring. By thus insuring that the film remains tightly wound in the film spool compartment, the film spool is protected against entrance of light. This protection is sufficient to enable one, if desired, to clamp the beginning of the film with the cover of the tank removed in subdued light. Finally, two resilient supporting metal strips that partially enclose the spool are provided in the film spool compartment for holding the film spool. These assist the action of the strip-off plate at the lower jaw of the clamp.

An embodiment of my invention is illustrated by way of example in the accompanying drawings wherein:

Fig. 1 is a cross section through a film spool compartment of the closed developing tank, showing a film spool in the compartment and the clamp for attachment of the beginning of the film held against the top edge of the partition between the film spool compartment and the developing container.

Fig. 2 is a plan view of the portion of the developing tank shown in Fig. 1, with the tank cover and film spool removed, and the guide plate folded back.

Fig. 3 is a side view of the clamp with its jaws open.

Fig. 4 is a side view of the clamp and section of a bowed metal rod used for closing the clamp.

The portion of the daylight developing tank illustrated in Fig. 1 shows a film spool compartment 2 arranged above and alongside of the developing container 1, which is closed by means of a cover 3. After inserting a roll film spool 4 provided with a protective paper strip 6 into the film spool compartment 2, the guide plate 5 is f d d wn and the b innint of the paper strip 6 is pulled thereover into the position shown. Since the guide plate 5, after being folded down, rests upon the outer winding of the film under the effect of a spring (n t sh wn). t fu s th urther purpose of preventing a loosening of the film windings.

Before the cover 3 of the developing tank is closed, the clamp 8 that serves to pull the film 7 into the developing container 1 is attached to the top edge of the partition 2a, separating the film spool compartment 2 from the developing container 1. This clamp (see Fig. 3) consists of a lower fixed jaw 8 and an upper movable jaw 8a. The lower jaw 8 is provided with a projection 8b that forms an acute angle therewith on the side away from the film spool compartment 2.

The attachment of the clamp at the upper edge of the partition 2a is accomplished by means of a bowed metal rod 11 that is rotatably mounted through the

side walls

9 and 10 of the developing tank parallel to the axis of the film spool compartment 2. The bowed-out portion 11:: of the rod fits into the acute angle formed between the fixed jaw 8 and the projection 85 of the clamp upon turning the rod 11 from outside the tank by means of the handle 11b. and forces the projection 8b against the partition 2a. In order to hold the clamp in its resultant position by means of the bowed rod 11, its handle 11b is logked by means of a suitable catch 9a on the tank wal The further procedure for developing the film may take place in full daylight with the developing tank closed. Upon pulling out of the protective paper strip 6, the beginning 7a of the film comes into position between the jaws of the clamp 8 as shown in Fig. 1. To assist in threading the film beginning 7a into the clamp, a strio-ofi plate 8c is attached to the inner end of the fixed jaw 8. This strip-off plate consists of a thin arched strip of metal that reaches beyond the free ends of the

clamp jaws

8 and 8a, and which. when the clamp is attached to the partition 2a, resiliently lies against the outer-most film winding on the film spool 4. By this means the beginning 7a of the film 7 is stripped oil from the roll film spool 4, as the protective paper strip 6 is withdrawn, and necessarily comes between the

open clamp jaws

8 and 8a. This condition may be recognized by a resistance against further pulling out of the paper strip 6. The action of the strip-oft plate 80 is supported by that of the resilient supporting

metal strips

12 and 13 that partly surround the roll film spool 4.

A peg 14 provided on the tank cover 3, whose normal position under the influence of a spring 15 is shown in Fig. 1, serves for closing the clamp. The peg 14 is so located that it passes through the cover 3 directly above the movable clamp jaw 3a. As one depresses the peg 14 its end 14a comes ,into contact with the movable clamp jaw 8a and upon further depression closes the clamp.

Instead of the peg 14, a bowed metal rod 16 (see Fig. 4) may be mounted in the side walls of the tank cover 3 parallel to the axis of the film spool compartment 2, and serve to close the clamp jaws. Its bowedout portion 16a, upon being swung from outside of the tank by means of a suitable handle, comes into contact with the movable clamp jaw 8a and upon further swinging in the direction of the arrow presses it down to close the clamp. There also exists the possibility of replacing the bowed-out portion of the rod 16 by some other suitable projection. Since the guide plate 5, after being folded down, prevents any loosening of the film windings, it protects against the entrance of light thereto. Consequently, there results the possibility of carrying out the clamping of the film beginning 7a between the

film javgs

8 and 8a with the cover 3 removed in subdued daylig t.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope hereof, it is to be understood that this invention is not limited to the specific embodiments hereof except as defined in the appended claims.

I claim:

1. A daylight developing tank for roll films having protective paper strips, which comprises a film spool compartment, a developing container, a cover for both, a developing spool in the latter provided with spirally grooved flanges, a pull-in band attached to the axle of the developing spool provided with a clamp having open jaws for grasping the beginning of the film, means operable from outside the tank when closed for releasably holding said clamp against a fixed part of the tank interior with jaws extended in the path of the film from the film spool compartment to the developing container, so that upon withdrawing the film from the film spool the beginning of the film is automatically introduced between the clamp jaws, and means also operable from outside the closed tank for pressing against the so held clamp to close its jaws on the beginning of the film.

2. A daylight developing tank as claimed in claim 1, wherein the open clamp is releasably held against the top edge of a partition between the film spool compartment and the developing container by rotatable means passing through a wall of the developing tank and including an interior extension that may be swung against the clamp.

3. A daylight developing tank as claimed in claim 1, wherein the means for releasably holding the open clamp in the path of the film includes a bowed rod rotatably mounted in the side walls of the tank parallel to the axis ofthe spool compartment.

4. A daylight developing tank as claimed in claim 1, wherein the lower jaw of the clamp is provided with a strip-off plate whose edge bears against the outer winding of the roll film in the film spool compartment.

5. A daylight developing tank as claimed in claim .1, wherein the cover for the tank is provided with a peg passing therethrough, which upon being depressed bears against and closes the clamp.

6. A daylight developing tank as claimed in claim 1, wherein the cover is provided with a rod that is rotatably mounted in depending side walls of the cover parallel to the axis of the film spool compartment and which has an extension that will swing upon rotation of the rod against the clamp to close it.

7. A dayli ht developing tank as claimed in claim 1, including a hinged guide plate above the film spool compartment which, when folded down, rests upon the roll film in said compartment and serves to guide the protective paper strip to the outside of the tank.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 938,287 Taylor Oct. 26, 1909 2,484,378 Freeman Oct. '11, 1949