Multi-part spool for processing film strip in a developing tank

Abstract

The present invention relates to a multi-part spool 1 for processing a film strip 2 in a processing tank 3. The spool 1 comprises a cylindrical outer reel 4 and inside it a concentrically located removable cylindrical inner reel 5. There is a helical groove 6, 7 on the external surface of the inner reel 5 as well as on the external surface of the outer reel 4, the faces 8 of which are configured to support the edges of the film strip 2. The helical groove 7 on inner reel and the helical groove 8 on outer reel have opposite run. There is at least one projection 9 projecting in radial direction at both ends of the inner reel 5 for centering the inner reel 5 in the cavity of the outer reel 4. The outer reel 4 comprises a hollow mandrel 10 projecting towards the cavity of the outer reel 4. The inner reel 5 comprises a sleeve 11 projecting towards the cavity of the inner reel 5, which is positioned on the mandrel 10 of the outer reel 4 in the assembled condition of the spool 1.

Description

TECHNICAL FIELD

[0001] The present invention relates to a multi-part spool for processing a film strip in a processing tank or any other suitable light resistant tank fulfilling the task of a processing tank. More specifically, the present invention relates to a spool for processing an 8 mm narrow gauge film, such as Kodak Super 8 cinema film.BACKGROUND ART

[0002] A known tank for processing an 8 mm cinema film is e.g., a special universal processing tank LOMO PM-451 from the company LOMO, comprising flat spools with spiral grooves positioned in several layers on top of each other, onto which the film strip is wound for processing.

[0003] United States patents US1924944A and US4001856A describe multi-part spools for processing a film strip. A multi-part spool is comprised of several cylindrical reels with successively smaller diameter placed in each other, with a helical groove on the outer side for holding the film strip.

[0004] The objective of the solution described in US4001856A is to process simultaneously several photo films, wherein each concentric reel has one film strip of a photo film. The system described is not intended for processing an 8 mm cinema film.

[0005] In the solution described in US1924944A, the helical groove of cylindrical reels placed in each other has alternately reverse run, enabling to process a long film strip distributed onto cylindrical reels placed in each other. In the said solution, handling of reels for winding the film strip onto them is complicated, as is the concentric placement of reels with wound film strip into each other.

[0006] The objective of the present invention is to propose a multi-part spool, which is relatively easy to handle and can be configured for use in the processing tanks already on the market. For example, a film processing tank of the type Paterson Super System 4 from the company Paterson Photographic Equipment is commonly used on the market, which is a cylindrical processing tank designated for simultaneous processing of several film strips of a photo film. Another objective of the present invention is to propose a multi-part spool, which can be adapted for use with such existing processing tank (film developing tank).DISCLOSURE OF THE INVENTION

[0007] The present invention provides a multi-part spool for a film strip for its processing in a processing tank. The spool comprises a hollow cylindrical outer reel and a removable hollow cylindrical inner reel located concentrically inside the outer reel.

[0008] There is a helical groove on the cylindrical external surface of the inner reel as well as on the cylindrical external surface of the outer reel, the faces of which are configured to support the edges of the film strip, so that the film strip does not contact the external side of the reel.

[0009] The helical groove on inner reel and the helical groove on outer reel have opposite run.

[0010] There is at least one projection projecting in radial direction at both ends of the inner reel for centering the inner reel in the cavity of the outer reel.

[0011] The outer reel comprises a hollow mandrel projecting towards the cavity of the outer reel at one end. The opening in the center of the mandrel is configured to receive the filling tube or spindle of the processing tank.

[0012] The inner reel comprises a sleeve projecting towards the cavity of the inner reel at one end, which is positioned around the mandrel of the outer reel in the assembled condition of the spool.

[0013] Such configuration keeps the inner reel concentrically inside the outer reel, so that the external side of the inner reel does not contact the internal side of the outer reel.

[0014] Preferably there are locking recesses on the lateral surface of the mandrel of the outer reel for receiving the locking lugs located on the internal surface of the sleeve of the inner reel.

[0015] In another embodiment of the invention, the mandrel of the outer reel and the sleeve of the inner reel form a bayonet coupling, or in other words, the locking recesses located on the lateral surface of the mandrel of the outer reel and the locking lugs located on the internal surface of the sleeve of the inner reel are configured as a bayonet coupling.

[0016] In yet another embodiment of the invention, a removable concentric bushing is located at the other end of the inner reel, which is directed towards the cavity of the inner reel.

[0017] It is configured to receive the filling tube or spindle of the processing tank and facilitates to center the spool in the processing tank.

[0018] A clamp for fixing the end of the film strip is located at one end of the inner reel at the beginning of the helical groove.

[0019] A notch is located at the end of the helical groove at the end of the outer reel located away from the mandrel for guiding the film strip wound on the helical groove of inner reel onto the helical groove of outer reel.

[0020] In yet another embodiment of the invention, the cylindrical part of the inner reel is comprised of at least two mutually permanently connected parts, in one part of which is the sleeve projecting towards the cavity of the reel.

[0021] In yet another embodiment of the invention, the cylindrical part of the outer reel is comprised of at least two mutually permanently connected parts, in one part of which is the mandrel projecting towards the cavity of the reel.

[0022] In yet another embodiment of the invention, the parts of reels of the spool are made by 3D printing of plastic material.

[0023] In yet another embodiment of the invention, the outer reel and the inner reel are made of translucent plastic. This is necessary e.g., for ensuring intermediate lighting during processing of reversal film, wherein an oblong light source is inserted into the inner reel instead of the filling tube or spindle of the processing tank.

[0024] The material is e.g., transparent polyethylene terephthalate (PETG) or any other suitable plastic material, such as acrylic nitrile butadiene styrene (ABS), acrylic nitrile styrene acrylate (ASA), which are also suitable for 3D printing.BRIEF DESCRIPTION OF DRAWINGS

[0025] The present invention is described below with references to the appended schematic figures, where: Figure 1 depicts a partial longitudinal section of a multi-part spool of the invention inside the processing tank; Figure 2 depicts a sideview of inner and outer reels of the spool of the invention; Figure 3 depicts a longitudinal section of the spool of the invention; Figure 4 depicts an axonometric view of partial section of the spool of the invention; Figure 5 depicts a lateral view of inner reel of the spool; Figure 6 depicts a lateral view of the spool of the invention with dispersed details; Figure 7 depicts an axonometric view of the spool of the invention with dispersed details; Figure 8 depicts a lateral view of the outer reel of the spool of the invention in the embodiment comprised of two parts before assembly; Figure 9 depicts a lateral view of the inner reel of the spool of the invention in the embodiment comprised of two parts before assembly; Figure 10 depicts an axonometric view of partial section of the outer reel of Figure 8; Figure 11 depicts an axonometric view of partial section of the inner reel of Figure 9; Figure 12 depicts an axonometric view of enlarged section of the spool of the invention in assembled condition. DESCRIPTION OF EMBODIMENTS

[0026] For the sake of clarity, on different figures the same details and elements have the same reference numbers.

[0027] In the example embodiment of Figure 1, the spool of the invention is illustrated in the film processing tank of the type Paterson Super System 4 from the company Paterson Photographic Equipment, which is common on the market. As seen in the figure, the outer reel 4 and the inner reel 5 are positioned on the filling tube / spindle 17, with which the spool is centered inside the processing tank 3, so that it does not contact the wall of the processing tank. The filling tube / spindle 14 is positioned through the bushing 14 located in the upper part of the inner reel 5 and through the mandrel 10 located in the lower part of the outer reel 4. The inner reel 5 is centered in the outer reel 4 with projections 9 and fixed in the outer reel 4 with mandrel 10 and sleeve 11 located in the lower part of the inner reel 5, the locking recesses 12 and locking lugs 13 of which form a bayonet coupling - see Figures 10, 11 and 12.

[0028] By adapting the shape of the bushing 14 and the mandrel 10, the spool 1 of the invention can be used with the processing tanks already available and sold on the market. In other words, the upper and lower ends of the spool can be adapted to be suitable for the peculiarities of the shape of the processing tank.

[0029] The spool 1 is comprised on two main parts, which are the outer reel 4 and the inner reel 5, on the external surface of which there is respectively a helical groove 6 and 7, the faces 8 of which are configured to support the edges of the film strip 2 - see Figures 2 and 5.

[0030] The outer reel 4, which is separately illustrated in Figures 8 and 10, is in the illustrated embodiment comprised of two parts 4a and 4b, which facilitates manufacturing of the reel 4. The upper part 4a has a notch 16, which is necessary for guiding the film strip during winding from the upper part of the inner reel 5 into the helical groove 6 of the outer reel 4. The mandrel 10 projecting concentrically towards the cavity of the reel 4 is located in the lower part 4b of the reel 4, with locking recesses 12 on the external surface, which form a bayonet coupling together with the locking lugs 13 located on the internal surface of the sleeve 11 of the inner reel 5 - see Figure 12.

[0031] In the reel 4 illustrated in Figure 8, also a vertical rabbet 18 is visible, which passes through the faces 8 of the helical groove 6 - this rabbet 18 is configured for receiving a rubber band, which fixes an end of the film strip on the reel 4 - this ensures that the rubber band does not hinder rotation of the spool in the processing tank.

[0032] The inner reel 5, which is separately illustrated in Figures 5, 9 and 11, is in the illustrated embodiment also comprised of two parts 5a and 5b, which facilitates manufacturing of the reel 5. At the edge of the upper part 5a there is a projection 9, which is configured for centering the inner reel 5 in the outer reel 4. The lower part 5b of the reel 5 comprises also a projection 9 at the lower edge. Furthermore, in the beginning of the helical groove 7 there is a clamp 15 for fixing the end of the film strip.

[0033] From Figure 12 it can be seen that bushing 14 is located in the upper part of the reel 5, which is configured for centering the reel 5 and thus the entire spool on the filling tube / spindle 17 (Figure 1) in the processing tank 3.

[0034] For winding the film strip 2 on the spool 1, the inner reel 5 is taken out of the outer reel 4 and then the end of the film strip 2 is fixed manually in the dark with the clamp 15 located in the lower part of the inner reel 5 to the beginning of the helical groove 7, and by rotating the inner reel 5 the film strip 2 is wound onto the helical groove 7 of the inner reel 5, until winding the film strip 2 reaches the upper end of the inner reel 5.

[0035] After that, the film strip is held manually in place on the inner reel 5 and the inner reel 5 with the film strip 2 is inserted into the outer reel 4.

[0036] A bayonet coupling is located in the bottom of the cavity of the outer reel 4, with which the inner reel 5 is fixed into place.

[0037] Then, winding of the film strip 2 onto the helical groove 6 of the outer reel 4 is continued through the notch 16 located in the upper part of the reel 4. As the helical groove 6 of the outer reel 4 has opposite threading compared to the helical groove 7 of the inner reel 5, upon winding into the helical groove 6 of the outer reel 4 the film strip 2 is wound in the same direction, when viewed from the end, but this winding will end in the lower part of the helical groove 6 of the outer reel 4. In the lower part of the helical groove 6 of the outer reel 4 the end of the film strip is fixed e.g., with a rubber band.

[0038] After that, the reels 4 and 5 with the wound film strip, inserted into each other, are placed into the processing tank 3 onto the filling tube 17 (which acts as a spindle of spools), and a lid is placed onto the processing tank 3.

[0039] Then the processing tank can be handled further in the light, and the processing solution can be poured into the processing tank.

[0040] The spool 1 comprised of the reels 4 and 5 of the invention enables to process e.g., an 8 mm film strip with the length 15.5 m (50 feet) included in a standard film cassette, and to use already available processing tanks designated for e.g., processing of several photo film strips.LIST OF REFERENCE NUMBERS

[0041] 1spool 2film strip 3processing tank 4outer reel 4a, 4bparts of outer reel 5inner reel 5a, 5bparts of inner reel 6helical groove on outer reel 7helical groove on inner reel 8faces of helical grooves 9projection 10mandrel 11sleeve 12locking recess 13locking lug 14bushing 15clamp 16notch 17filling tube / spindle 18rabbet

Examples

Embodiment Construction

[0026]For the sake of clarity, on different figures the same details and elements have the same reference numbers.

[0027]In the example embodiment of Figure 1, the spool of the invention is illustrated in the film processing tank of the type Paterson Super System 4 from the company Paterson Photographic Equipment, which is common on the market. As seen in the figure, the outer reel 4 and the inner reel 5 are positioned on the filling tube / spindle 17, with which the spool is centered inside the processing tank 3, so that it does not contact the wall of the processing tank. The filling tube / spindle 14 is positioned through the bushing 14 located in the upper part of the inner reel 5 and through the mandrel 10 located in the lower part of the outer reel 4. The inner reel 5 is centered in the outer reel 4 with projections 9 and fixed in the outer reel 4 with mandrel 10 and sleeve 11 located in the lower part of the inner reel 5, the locking recesses 12 and locking lugs 13 of which fo...

TECHNICAL FIELD

[0001] The present invention relates to a multi-part spool for processing a film strip in a processing tank or any other suitable light resistant tank fulfilling the task of a processing tank. More specifically, the present invention relates to a spool for processing an 8 mm narrow gauge film, such as Kodak Super 8 cinema film.BACKGROUND ART

[0002] A known tank for processing an 8 mm cinema film is e.g., a special universal processing tank LOMO PM-451 from the company LOMO, comprising flat spools with spiral grooves positioned in several layers on top of each other, onto which the film strip is wound for processing.

[0003] United States patents US1924944A and US4001856A describe multi-part spools for processing a film strip. A multi-part spool is comprised of several cylindrical reels with successively smaller diameter placed in each other, with a helical groove on the outer side for holding the film strip.

[0004] The objective of the solution described in US4001856A is to process simultaneously several photo films, wherein each concentric reel has one film strip of a photo film. The system described is not intended for processing an 8 mm cinema film.

[0005] In the solution described in US1924944A, the helical groove of cylindrical reels placed in each other has alternately reverse run, enabling to process a long film strip distributed onto cylindrical reels placed in each other. In the said solution, handling of reels for winding the film strip onto them is complicated, as is the concentric placement of reels with wound film strip into each other.

[0006] The objective of the present invention is to propose a multi-part spool, which is relatively easy to handle and can be configured for use in the processing tanks already on the market. For example, a film processing tank of the type Paterson Super System 4 from the company Paterson Photographic Equipment is commonly used on the market, which is a cylindrical processing tank designated for simultaneous processing of several film strips of a photo film. Another objective of the present invention is to propose a multi-part spool, which can be adapted for use with such existing processing tank (film developing tank).DISCLOSURE OF THE INVENTION

[0007] The present invention provides a multi-part spool for a film strip for its processing in a processing tank. The spool comprises a hollow cylindrical outer reel and a removable hollow cylindrical inner reel located concentrically inside the outer reel.

[0008] There is a helical groove on the cylindrical external surface of the inner reel as well as on the cylindrical external surface of the outer reel, the faces of which are configured to support the edges of the film strip, so that the film strip does not contact the external side of the reel.

[0009] The helical groove on inner reel and the helical groove on outer reel have opposite run.

[0010] There is at least one projection projecting in radial direction at both ends of the inner reel for centering the inner reel in the cavity of the outer reel.

[0011] The outer reel comprises a hollow mandrel projecting towards the cavity of the outer reel at one end. The opening in the center of the mandrel is configured to receive the filling tube or spindle of the processing tank.

[0012] The inner reel comprises a sleeve projecting towards the cavity of the inner reel at one end, which is positioned around the mandrel of the outer reel in the assembled condition of the spool.

[0013] Such configuration keeps the inner reel concentrically inside the outer reel, so that the external side of the inner reel does not contact the internal side of the outer reel.

[0014] Preferably there are locking recesses on the lateral surface of the mandrel of the outer reel for receiving the locking lugs located on the internal surface of the sleeve of the inner reel.

[0015] In another embodiment of the invention, the mandrel of the outer reel and the sleeve of the inner reel form a bayonet coupling, or in other words, the locking recesses located on the lateral surface of the mandrel of the outer reel and the locking lugs located on the internal surface of the sleeve of the inner reel are configured as a bayonet coupling.

[0016] In yet another embodiment of the invention, a removable concentric bushing is located at the other end of the inner reel, which is directed towards the cavity of the inner reel.

[0017] It is configured to receive the filling tube or spindle of the processing tank and facilitates to center the spool in the processing tank.

[0018] A clamp for fixing the end of the film strip is located at one end of the inner reel at the beginning of the helical groove.

[0019] A notch is located at the end of the helical groove at the end of the outer reel located away from the mandrel for guiding the film strip wound on the helical groove of inner reel onto the helical groove of outer reel.

[0020] In yet another embodiment of the invention, the cylindrical part of the inner reel is comprised of at least two mutually permanently connected parts, in one part of which is the sleeve projecting towards the cavity of the reel.

[0021] In yet another embodiment of the invention, the cylindrical part of the outer reel is comprised of at least two mutually permanently connected parts, in one part of which is the mandrel projecting towards the cavity of the reel.

[0022] In yet another embodiment of the invention, the parts of reels of the spool are made by 3D printing of plastic material.

[0023] In yet another embodiment of the invention, the outer reel and the inner reel are made of translucent plastic. This is necessary e.g., for ensuring intermediate lighting during processing of reversal film, wherein an oblong light source is inserted into the inner reel instead of the filling tube or spindle of the processing tank.

[0024] The material is e.g., transparent polyethylene terephthalate (PETG) or any other suitable plastic material, such as acrylic nitrile butadiene styrene (ABS), acrylic nitrile styrene acrylate (ASA), which are also suitable for 3D printing.BRIEF DESCRIPTION OF DRAWINGS

[0025] The present invention is described below with references to the appended schematic figures, where: Figure 1 depicts a partial longitudinal section of a multi-part spool of the invention inside the processing tank; Figure 2 depicts a sideview of inner and outer reels of the spool of the invention; Figure 3 depicts a longitudinal section of the spool of the invention; Figure 4 depicts an axonometric view of partial section of the spool of the invention; Figure 5 depicts a lateral view of inner reel of the spool; Figure 6 depicts a lateral view of the spool of the invention with dispersed details; Figure 7 depicts an axonometric view of the spool of the invention with dispersed details; Figure 8 depicts a lateral view of the outer reel of the spool of the invention in the embodiment comprised of two parts before assembly; Figure 9 depicts a lateral view of the inner reel of the spool of the invention in the embodiment comprised of two parts before assembly; Figure 10 depicts an axonometric view of partial section of the outer reel of Figure 8; Figure 11 depicts an axonometric view of partial section of the inner reel of Figure 9; Figure 12 depicts an axonometric view of enlarged section of the spool of the invention in assembled condition. DESCRIPTION OF EMBODIMENTS

[0026] For the sake of clarity, on different figures the same details and elements have the same reference numbers.

[0027] In the example embodiment of Figure 1, the spool of the invention is illustrated in the film processing tank of the type Paterson Super System 4 from the company Paterson Photographic Equipment, which is common on the market. As seen in the figure, the outer reel 4 and the inner reel 5 are positioned on the filling tube / spindle 17, with which the spool is centered inside the processing tank 3, so that it does not contact the wall of the processing tank. The filling tube / spindle 14 is positioned through the bushing 14 located in the upper part of the inner reel 5 and through the mandrel 10 located in the lower part of the outer reel 4. The inner reel 5 is centered in the outer reel 4 with projections 9 and fixed in the outer reel 4 with mandrel 10 and sleeve 11 located in the lower part of the inner reel 5, the locking recesses 12 and locking lugs 13 of which form a bayonet coupling - see Figures 10, 11 and 12.

[0028] By adapting the shape of the bushing 14 and the mandrel 10, the spool 1 of the invention can be used with the processing tanks already available and sold on the market. In other words, the upper and lower ends of the spool can be adapted to be suitable for the peculiarities of the shape of the processing tank.

[0029] The spool 1 is comprised on two main parts, which are the outer reel 4 and the inner reel 5, on the external surface of which there is respectively a helical groove 6 and 7, the faces 8 of which are configured to support the edges of the film strip 2 - see Figures 2 and 5.

[0030] The outer reel 4, which is separately illustrated in Figures 8 and 10, is in the illustrated embodiment comprised of two parts 4a and 4b, which facilitates manufacturing of the reel 4. The upper part 4a has a notch 16, which is necessary for guiding the film strip during winding from the upper part of the inner reel 5 into the helical groove 6 of the outer reel 4. The mandrel 10 projecting concentrically towards the cavity of the reel 4 is located in the lower part 4b of the reel 4, with locking recesses 12 on the external surface, which form a bayonet coupling together with the locking lugs 13 located on the internal surface of the sleeve 11 of the inner reel 5 - see Figure 12.

[0031] In the reel 4 illustrated in Figure 8, also a vertical rabbet 18 is visible, which passes through the faces 8 of the helical groove 6 - this rabbet 18 is configured for receiving a rubber band, which fixes an end of the film strip on the reel 4 - this ensures that the rubber band does not hinder rotation of the spool in the processing tank.

[0032] The inner reel 5, which is separately illustrated in Figures 5, 9 and 11, is in the illustrated embodiment also comprised of two parts 5a and 5b, which facilitates manufacturing of the reel 5. At the edge of the upper part 5a there is a projection 9, which is configured for centering the inner reel 5 in the outer reel 4. The lower part 5b of the reel 5 comprises also a projection 9 at the lower edge. Furthermore, in the beginning of the helical groove 7 there is a clamp 15 for fixing the end of the film strip.

[0033] From Figure 12 it can be seen that bushing 14 is located in the upper part of the reel 5, which is configured for centering the reel 5 and thus the entire spool on the filling tube / spindle 17 (Figure 1) in the processing tank 3.

[0034] For winding the film strip 2 on the spool 1, the inner reel 5 is taken out of the outer reel 4 and then the end of the film strip 2 is fixed manually in the dark with the clamp 15 located in the lower part of the inner reel 5 to the beginning of the helical groove 7, and by rotating the inner reel 5 the film strip 2 is wound onto the helical groove 7 of the inner reel 5, until winding the film strip 2 reaches the upper end of the inner reel 5.

[0035] After that, the film strip is held manually in place on the inner reel 5 and the inner reel 5 with the film strip 2 is inserted into the outer reel 4.

[0036] A bayonet coupling is located in the bottom of the cavity of the outer reel 4, with which the inner reel 5 is fixed into place.

[0037] Then, winding of the film strip 2 onto the helical groove 6 of the outer reel 4 is continued through the notch 16 located in the upper part of the reel 4. As the helical groove 6 of the outer reel 4 has opposite threading compared to the helical groove 7 of the inner reel 5, upon winding into the helical groove 6 of the outer reel 4 the film strip 2 is wound in the same direction, when viewed from the end, but this winding will end in the lower part of the helical groove 6 of the outer reel 4. In the lower part of the helical groove 6 of the outer reel 4 the end of the film strip is fixed e.g., with a rubber band.

[0038] After that, the reels 4 and 5 with the wound film strip, inserted into each other, are placed into the processing tank 3 onto the filling tube 17 (which acts as a spindle of spools), and a lid is placed onto the processing tank 3.

[0039] Then the processing tank can be handled further in the light, and the processing solution can be poured into the processing tank.

[0040] The spool 1 comprised of the reels 4 and 5 of the invention enables to process e.g., an 8 mm film strip with the length 15.5 m (50 feet) included in a standard film cassette, and to use already available processing tanks designated for e.g., processing of several photo film strips.LIST OF REFERENCE NUMBERS

[0041] 1spool 2film strip 3processing tank 4outer reel 4a, 4bparts of outer reel 5inner reel 5a, 5bparts of inner reel 6helical groove on outer reel 7helical groove on inner reel 8faces of helical grooves 9projection 10mandrel 11sleeve 12locking recess 13locking lug 14bushing 15clamp 16notch 17filling tube / spindle 18rabbet

Examples

Embodiment Construction

[0026]For the sake of clarity, on different figures the same details and elements have the same reference numbers.

[0027]In the example embodiment of Figure 1, the spool of the invention is illustrated in the film processing tank of the type Paterson Super System 4 from the company Paterson Photographic Equipment, which is common on the market. As seen in the figure, the outer reel 4 and the inner reel 5 are positioned on the filling tube / spindle 17, with which the spool is centered inside the processing tank 3, so that it does not contact the wall of the processing tank. The filling tube / spindle 14 is positioned through the bushing 14 located in the upper part of the inner reel 5 and through the mandrel 10 located in the lower part of the outer reel 4. The inner reel 5 is centered in the outer reel 4 with projections 9 and fixed in the outer reel 4 with mandrel 10 and sleeve 11 located in the lower part of the inner reel 5, the locking recesses 12 and locking lugs 13 of which fo...

Claims

1. A multi-part spool (1) for processing a film strip (2) in a processing tank (3), wherein the spool (1) comprises a hollow cylindrical outer reel (4) and inside it a concentrically located removable hollow cylindrical inner reel (5), wherein there is a helical groove (6, 7) on the cylindrical external surface of the inner reel (5) as well as on the cylindrical external surface of the outer reel (4), the faces (8) of which are configured to support the edges of the film strip (2), and wherein the helical groove (7) on the inner reel and the helical groove (8) on the outer reel have an opposite run, characterized in that there is at least one projection (9) projecting in radial direction at both ends of the inner reel (5) for centering the inner reel (5) in the cavity of the outer reel (4), the outer reel (4) comprises a hollow mandrel (10) projecting towards the cavity of the outer reel (4) at one end, the inner reel (5) comprises a sleeve (11) projecting towards the cavity of the inner reel (5) at one end, which is positioned around the mandrel (10) of the outer reel (4) in the assembled condition of the spool (1).

2. The multi-part spool (1) according to claim 1, characterized in that there are locking recesses (12) on the lateral surface of the mandrel (10) of the outer reel (4) for receiving the locking lugs (13) located on the internal surface of the sleeve (11) of the inner reel (5).

3. The multi-part spool (1) according to claim 2, characterized in that the mandrel (10) of the outer reel (4) and the sleeve (11) of the inner reel (5) form a bayonet coupling.

4. The multi-part spool (1) according to any preceding claim 1 to 3, characterized in that a removable concentric bushing (14) is located at the other end of the inner reel (5), which is directed towards the cavity of the inner reel (5).

5. The multi-part spool (1) according to any preceding claim 1 to 4, characterized in that a clamp (15) for fixing the end of the film strip (2) is located at one end of the inner reel (5) at the beginning of the helical groove (7).

6. The multi-part spool (1) according to any preceding claim 1 to 4, characterized in that a notch (16) is located at the end of the helical groove (6) at the end of the outer reel (4) located away from the mandrel (10) for guiding the film strip (2) wound on the helical groove (7) of inner reel (5) onto the helical groove (6) of outer reel (4).

7. The multi-part spool (1) according to any preceding claim 1 to 6, characterized in that the cylindrical part of the inner reel (5) is comprised of at least two parts (5a, 5b), in one part of which is the sleeve (11) projecting towards the cavity of the reel (5).

8. The multi-part spool (1) according to any preceding claim 1 to 7, characterized in that the cylindrical part of the outer reel (4) is comprised of at least two parts (4a, 4b), in one part of which is the mandrel (10) projecting towards the cavity of the reel (4).

9. The multi-part spool (1) according to any preceding claim, characterized in that the parts of reels (4, 5) of the spool (1) are made by 3D printing.

10. The multi-part spool (1) according to any preceding claim, characterized in that the outer reel (4) and the inner reel (5) are made of translucent plastic.

Images