Photographic film spool

Abstract: A photographic film spool has a spool core, a pair of flanges and a pair of walls facing each other which form the slot for film insertion, and the spool comprises, one of the walls having a ramp portion which is formed so as to approach the other wall gradually according to the direction of film insertion, a retention hook, which is provided around the top of the ramp portion, engaging an aperture of the trailing end of the photographic film, and penetrated portions, which are formed on both sides of the retention hook, penetrating in the direction perpendicular to the direction of film insertion, and the other of the walls having a hold-down projection which inhibits the photographic film to detach from the retension hook. The spool can easily remove the trailing end of the photographic film from the spool core without damage after use.

Description: BACKGROUND OF THE INVENTION This invention relates to a photographic film spool according to the preamble of claim 1 for winding a photographic film. Such a film spool is known from EP-A-O 356 926. In the conventional photographic film spool, a slot for film insertion is formed on the spool core. A pair of hooks are provided on one of facing walls of the slot, and a rib to inhibit slipping out of film is provided on the other wall. The rib to inhibit slipping out is disposed on the part to counter the center between the above hooks. The trailing end of the photographic film is engaged with the hooks and the rib to inhibit slipping out (Japanese Utility Model KOKAI No. 58-178143, Japanese Patent KOKAI Nos. 58-203436, 62-240957). When photographing is finished, the photographic film engaged with the spool core is cut off near the spool, and then developed. The trailing end portion of the photographic film cut off is still engaged with the hooks and the rib to inhibit slipping out, and remains on the spool core. Incidentally, resource saving has recently been required widely, and used spools become to be recycled. In the recycling, the trailing end portion of the photographic film engaged with the spool core is an impurity, and therefore, it must be removed. However, in the above conventional spool, it was difficult to remove the photographic film without damage, and powder of the base resin, photographic emulsion and the like generated and contaminated the plastic produced by recycling spool. SUMMARY OF THE INVENTION An object of the invention is to provide a photographic film spool capable of removing the trailing end of the photographic film from the spool core without damage. This object is solved according to the invention with a photographic film spool having the features as set out in claim 1. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a front view of a photographic film spool embodying the invention illustrating the fixation state of the photographic film. Figure 2 is a sectional view taken along line A-A in Figure 1. Figure 3 is a plan view of the photographic film spool of Figure 1 with partially cutaway. Figure 4 is a front view of the photographic film spool of Figure 1 illustrating the state of film insertion. Figure 5 is a front view of another photographic film spool also embodying the invention illustrating the fixation state of the photographic film. Figure 6 is a sectional view taken along line B-B of in Figure 5. Figure 7 is a plan view of the photographic film spool of Figure 5 with partially cutaway. Figure 8 is a front view of the photographic film spool of Figure 5 illustrating the state of film insertion. Figure 9 is a front view of a comparative photographic film spool embodying the invention illustrating the fixation state of the photographic film. Figure 10 is a sectional view taken along line A-A in Figure 9. Figure 11 is a plan view of the photographic film spool of Figure 9 with partially cutaway. Figure 12 is a front view of the photographic film spool of Figure 9 illustrating the state of film insertion. Figure 13 is a graphical data showing the superiority of the present invention. List of reference numbers 10 ... Photographic film spool 11 ... Slot for film insertion 12 ... Photographic film 13 ... Trailing end of the photographic film 14 ... Aperture 20 ... Spoul core 30 ... Flange 40... Wall 42,53 ... Ramp portion (Inclined front portion) 63 ... Retention hook 44 ... Penetrated portion 50 ... Wall 52 ... Hold-down projection P ... Direction of film insertion DETAILED DESCRIPTION OF THE INVENTION The number of a set of the ramp portion and the retention hook may be one or more. When the number is one, the penetrated portion is provided on both sides of the retention hook. When the number is two, the penetrated portion may be provided on both sides of each retention hook. Alternatively, one penetrated portion is provided between the retention hooks, and used as the penetrated portion for both retention hooks. The penetrated portion is provided on both sides of the retention hook. However, when there are two or more retention hooks, each penetrated portion between retention hooks is used as the common penetration for both retention hooks. The penetrated portion formed on one wall may be in various form and size capable of inserting a jig for pressing film from the outside of the spool core. For example, the penetrated portion may be a slit (in a state that one side wall is absent), a hole (in a state that there are all side walls), a rectangle or a circle. A section of the hold-down projection in the insertion direction of photographic film may be in various form, such as rectangle, trapezoid, triangle, semicircle or angle form, and preferred forms are gradually narrower in the insertion direction in view of the removal of film. In the photographic film spool of the invention, at the time of engaging the photographic film with the spool core, when the trailing end of the photographic film is inserted into the slot for film insertion, the trailing end is guided along the ramp portion or the hold-down projection of the wall to almost the center of the slot for film insertion. The trailing end is further thrusted while it is deformed by the pushing of the retention hook onto both sides of trailing end and by the pushing of the hold-down projection onto almost the central portion in the opposite direction to each other. When the retention hook is inserted into the aperture of the trailing end, the trailing end returns in a flat form by its restitutive force. In this state, the movement of the trailing end in the inserting direction is restricted by the ramp portion and the retention hook, and the movement in the cross direction is restricted by the hold-down projection. As a result, the trailing end is fixed so as not to detach from the spool core. Subsequently, the photographic film is detached from the spool core, for example, a jig for pressing film is inserted into the slot for film insertion through the penetrated portions provided on both sides. The trailing end on both sides of the retention hook is pressed towards the other wall. Thereby, the aperture of the trailing end is released from the engagement by the retention hook, and the trailing end is detached from the spool core without damage. As mentioned above, since the photographic film spool of the invention has penetrated portions provided in the direction perpendicular to the direction of film insertion on both sides of the retention hook on one of the walls, the trailing end of the photographic film engaged with the spool core can be detached from the spool core without damage. As a result, recycled plastic can be produced efficiently from the spool without impurities. EMBODIMENTS An emodiment of the photographic film spool of the invention is illustrated in Figures 1 through 4. As shown in the figures, the photographic film spool 10 (hereinafter simply referred to as spool) is composed of a spool core 20, a pair of walls 40,50 faced each other which form a slot 11 for film insertion around the center of the spool core 20, and a pair of flanges 30,30 near both sides of the spool core 20 in the axial direction. The spool 10 has the spool core 20 with a generally cylindrical surface 21, and the photographic film 12 is wound around the periphery. The flanges 30,30 are provided on the spool core 20 at a distance therebetween slightly longer than the width of the photographic film 12. Near both side ends of one of the walls 40, a pair of ramp portions 42,42 are formed so as to approach the other wall 50 gradually according to the direction P of film insertion. Retention hooks 43,43 are formed for engaging the aperture 14 of the trailing end 13 of the photographic film 12 after the top of respective ramp portions 42,42. Penetrated portions 44,44,44, which penetrate in the direction perpendicular to the direction P of film insertion, are formed on the outsides of and between the retention hooks 43,43. A jig for pressing film (not illustrated) can be inserted from the outside of the spool core 20 into the penetrated portions 44,44,44. A hold-down projection 52 having a rectangle in a section in the horizontal direction in the figure is projected from around the center of the other wall 50. The hold-down projection 52 is provided with a ramp portion 53 to approach to the counter wall 40 gradually in the direction P to insert the photographic film 12 and a presser 54 following the ramp portion 53 almost in parallel to the wall 40. In the case of engaging the photographic film 12 with the spool core 20, the trailing end 13 is inserted into the slot 11 for film insertion. Then, the trailing end 13 is guided by the ramp portion 42 or 53, and as shown in Figure 4, the trailing end 13 is further inserted while it is deformed by the retention hooks 43,43 and the presser 54. At the moment of entering the retention hooks 43,43 into the apertures 14,14 of the trailing end 13, the deformation is reformed by the restitutive force of the photographic film 12, and as shown in Figures 2 and 3, it becomes flat. On that occasion, the movement of the trailing end 13 is restricted by the presser 54, and the aperture 14,14 of the trailing end 13 are engaged with the retention hooks 43,43. As a result, the photographic film 12 is surely fixed to the spool core 20. After exposure, the photographic film 12 is cut off near the spool 10, and dveloped. The trailing end 13 of the photographic film 12 is removed from the spool 10, the spool 10 is recycled. As a method of removing the trailing end 13 of the photographic film 12 from the spool core 20 prior to recycling, a jig for pressing film is inserted into the penetrated portions 44,44,44 formed on one wall 40. Three portions of the trailing end 13 positioning on both sides of the retention hooks 43,43 are pressed towards the other wall 50 by the jig for pressing film. As a result, the apertures 14,14 of the trailing end 13 are released from the retention hooks 43,43, and the trailing end 13 of the photographic film 12 is detached from the spool core 20 without damage. Since the above photographic film spool has the penetrated portions 44,44,44 formed on the outsides of and between the retention hooks 43,43 on one wall 40 in the direction perpendicular to the direction of film insertion, the trailing end 13 is not damaged by removing the trailing end 13 of the photographic film 12 engaged with the spool core 20. On the other hand, when the trailing end 13 of the photographic film 12 is inserted into the slot 11 for film insertion, the top of the photographic film 12 bent by the hold-down projection 52 is protruded into the penetrated portion 44. Thereby, the photographic film 12 does not contact the wall 40. Accordingly, buckling of the photographic film 12 does not occur at the top portion, and insertion resistance is decreased. Another embodiment of the photographic film spool of the invention is illustrated in Figures 5 through 8. In the spool of this embodiment, the ramp portion 42 is formed at the center of one wall 40 so as to approach the other wall 50 gradually according to the direction P of film insertion, and a retention hook 43 is formed after the top of the ramp portion 42. Penetrated portions 44,44, which penetrate in the direction perpendicular to the direction P of film insertion, are formed on the wall 40 on both sides of the retention hook 43. Hold-down projections 52,52 are formed near both side ends of the other wall 50. The other constructions are similar to the aforementioned spool shown in Figures 1 through 4. In the case of engaging the photographic film 12 with the spool core 20, similar to the aforementioned case, the trailing end 13 is guided by the ramp portion 42,53. Then, as shown in Figure 8, the trailing end 13 is further inserted while it is deformed by the retention hook 43 and the presser 54, and the aperture 14 of the trailing end 13 is engaged with the retention hook 43. To remove the trailing end 13 of the photographic film 12 is carried out similar to the aforementioned case. That is, a jig for pressing film is inserted into the penetrated portions 44,44 to push up the trailing end 13 toward the wall 50, and thereby, the aperture 14 is released from the retention hook 43. Comparative embodiments illustrated in Figures 9 through 12 may be similar to Figures 1 through 4 except that they have only one penetrated portion 44 between the retention hooks 43,43. EXAMPLE We prepared 50 samples of each following types of photographic film spools: 1: Conventional spool for the photographic film 2: Photographic film spool, illustrated in Figures 9 through 12, which has only one penetrated portion 44 between the retention hooks, 43,43 3: Photographic film spool of this invention which is illustrated in Figures 1 through 4 After engaging photographic film to these spools, removability of the trailing end of the photographic film from the spool core was compared. As a result, capable rate of removing the trailing end of the photographic film from the spool core without damage were plot on Figure 13.

Claims: A photographic film spool (10) having a spool core (20) for winding a photographic film (12) thereon, a pair of flanges (30) provided on both sides in an axial direction of the spool core (20) for restricting the movement of the photographic film (12) in the axial direction, a slot (11) for film insertion formed in the spool core (20) into which the trailing end (13) of the photographic film (12) is inserted, and first and second walls (40, 50) facing each other which form the slot (11) for film insertion, wherein said first wall (40) has at least one ramp portion (42) being formed so as to approach the second wall (50) gradually in the direction (P) of film insertion, at least one retention hook (43), provided after the top of said at least one ramp portion (42), for engaging an aperture (14) of the trailing end (13) of the photographic film (12), and a penetrated portion (44) extending in a direction perpendicular to the direction (P) of film insertion, and said second wall (50) has at least one hold-down projection (52) extending toward said first wall (40) characterized in that said at least one retention hook (43) is so shaped as to be adapted for releasing the trailing end (13) when said trailing end (13) is pushed toward the second wall (50), in that said at least one hold-down projection (52) of said second wall is adapted for inhibiting inadvertent detaching of said trailing end from said at least one retention hook (43), and in that said penetrated portion (44) is formed on both sides of said at least one retention hook (43), so as to allow access for a jig pushing on portions of the trailing end (13) on both sides of said at least one retention hook (43) for exerting a pressing force toward the second wall (50), wherein either the number of the retention hook is two and the number of the hold-down projection is one, or the number of the retention hook is one and the number of the hold-down projection is two. The spool of claim 1 wherein the side of said at least one retention hook (43), engaging said aperture of the trailing and of the photographic film, is inclined backward with respect to the direction of the film insertion in the slot and protrudes from the first wall at an angle capable of engaging the aperture of the trailing end and capable of releasing said aperture of said trailing end (13) when said trailing end (13) is pushed toward the second wall (50). The spool of claim 1 wherein the at least one hold down projection (52) includes a presser (54) adapted for catching said trailing end provided subsequent to the ramp portion. The spool of claim 1 wherein said at least one retention hook (43) is a V-shaped hook having a first and a second portion inclined respectively with respect to the first wall and the second wall of the spool and located under the ramp portion (42) with resepct to the first wall.

Inventors: MITAKE HIROSHI, MITAKE, HIROSHI, Mitake, Hiroshi, c/o Fuji Photo Film Co., Ltd.
Applicants: FUJI PHOTO FILM CO LTD, FUJI PHOTO FILM CO., LTD.
Application year: 1993
Main classification: G03D13
IPC codes: G03B17, G03C3