GB1574456A

GB1574456A - Film registration device

Info

Publication number: GB1574456A
Application number: GB1509577A
Authority: GB
Original assignee: Goldmacher H K
Current assignee: Goldmacher H K
Priority date: 1977-04-12
Filing date: 1977-04-12
Publication date: 1980-09-10

Description

(54) FILM REGISTRATION DEVICE (71) I, HOWARD KAY GOLDMACHBR, a citizen of the United States of America, of 136 Worthen Road, Lexington, Mass, 02173, U.S.A., do hereby declare the invention for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: BACKGROUND OF THE INVENTION Field of the Invention The invention relates to a film strip having a device for providing a predetermined registration of the film in a camera, the device more specifically, allowing a partially-exposed 35mm film strip packaged in a film cassette to be rewound, removed from the camera, subsequently reinserted into the camera, and advanced to the next unexposed frame accurately.

Description of the Prior Art Users of 35mm cameras have available many different types of film-for example, monochromatic films of various film speeds and grain characteristics; color films of negative and reversal type; and special process films. It is the practice in the art to package 35mm film in cartridges or cassettes having sufficient length for 20 or 36 exposures. Both professional and amateur photographers experince occasions in which the film in the camera is not the type appropriate for the particular photographic situation at hand. For such occasions, professional photographers typically utilize multiple cameras, each loaded with a different type of film. Needless to say, this approach is too expensive for many amateur photographers. Large format cameras having interchangeable filmholding backs are also in common use for this purpose, but are not available for 35mm cameras.

However, when the photographer desires to use one 35mm camera and this need arises, he may resort to rewinding the partially-exposed film back into its cassette, removing the cassette and installing another cassette of film. To save the un- exposed film of the first cassette for future use, he must be very careful not to wind the tongue end of the film completely into the cassette, as it would then not be possible to recover the film end.

When subsequently reinstalling a correctly-rewound cassette into the camera, there is no inherent index on or associated with the film to ensure that the actual positions of the previously exposed frames coincide with the shutter opening or that the numbers of the exposed frames are correctly synchronized with the frame counter of the camera. Consequently, it is common practice to advance the film one or two frames beyond the number of the last exposed frame as read on the film counter. This action creates "safety frames" to prevent possible overlap of the last previously exposed frame and the next frame exposed after such reinstallation. As may be recognized, the safety frame space represents a waste of film. Another problem arises with this method since automatic commercial film processing equipment may cut the film strip into short lengths of four or five frames based on indexing to the first frame. If the space is not an exact integral number of frames, there is the danger that this operation will result in cutting into the picture area of the misaligned, later-exposed frames.

It is therefore a primary object of my invention to provide a film strip for use in a cassette, - the strip having a registration device for allowing a number of frames less than the total number of the film to be exposed in a 35 mm camera, the film to be safely rewound, the last exposed frame number indicated and the partially exposed film cassette to be re installed in the camera, with the exposed frames correctly aligned with the shutter opening and the frame numbers of the previously exposed frames synchronized with the frame counter.

A further object of the invention is to provide a simple and cheap method of modifying a film strip to enable it to be used as described above.

According to the present invention there is provided a film strip for attachment at one end to a film cassette spool for insertion in a camera, the other end being formed as a narrowed tongue portion for engagement with the camera spool, the film strip having a projection upstanding from or adjacent the tongued portion thereof for engaging the cassette, in use, to resist winding of the tongued portion thereinto and index means adjacent the projection and aligned with at least one of a plurality of sprocket holes along a longitudinal edge of the film for use in registering the said projection in a given location with respect to the camera sprocket, the projection being so formed as to allow the film to be wound on to the camera spool, in use.

A cassette containing a film strip according to the invention may thus be loaded into a camera with the projection registered in a predetermined location with respect to the sprockets. Any desired number of film frames may then be exposed and the film may be rewound into the cassette to allow its replacement by another film.

When the film is rewound the projection will engage the cassette, resisting further rewinding and notifying the user that the film is sufficiently rewound to allow its removal; the tongue remains exposed so that the film can be replaced in the camera when required.

On replacement of the partly exposed film the index means allow the projection to be registered in exactly the same location with respect to the sprockets as previously to ensure exact registration of exposed frames with the shutter opening and synchronism of the frames with the frame counter of the camera. Thus when the film is wound on to align an unexposed portion with the shutter opening there will be no wastage of film and no danger of incorrect cutting of the film during processing by automatic equipment.

A set of numerals of from one to at least the number of film frames of the strip, the individual numerals of which are readily removable, is preferably provided either on the tab or on a cassette incorporating a film strip as described above. This feature allows the number of frames exposed prior to removal of the film strip to be recorded. Preferably the numerals are deposited on a decalomania substrate so that they may easily be rubbed off, for example with a finger.

The film strip of the invention may, for example, have a portion of a generally rectangular tab of flexible material glued thereto a free end portion of the tab closer to that end of the strip for attachment to the cassette spool being bent out of the plane of the glued portion along a line substantially perpendicular to the longitudinal axis of the strip to form the projection. In this case the index may comprise two marks on the glued portion of the tab, aligned with respective sprocket holes in the film. Alternatively the projection may comprise a rectangular flap portion of the film strip which is bent out of the plane of the strip along a line substantially perpendicular to the longitudinal axis of the strip, forming an aperture in the strip extending from the said line towards that end of the strip for attachment to the cassette, the index means being formed by the edges of the said aperture.

The present invention further comprehends a film cassette incorporating a film strip as described above and a method of modifying a film strip attached at one end to a film cassette spool for insertion in a camera, the other end being formed as a narrowed tongued portion for engagement with a camera spool, in which an atleast-partially-collapsable projection is formed on or adjacent the tongued portion for engaging the cassette, in use, to resist winding of the tongued portion thereinto, the projection being collapsable to allow winding of the film on to the camera spool, and in which index means are formed simultaneously adjacent the projection in alignment with at least one of a plurality of socket holes along a longs tudinal edge of the film for use in registering the said projection in a given location with respect to the camera sprocket.

Other objects and advantages of my invention will become apparent from the following detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING Figure 1 is a perspective view of a tab device to be attached to a 35mm film tongue end and an index marker in accordance with a preferred embodiment of mv invention Figure 2a is a partial side view of the tab of Figure 1 showing the laminated construction thereof, Figure 2b is a partial side view of a tab showing an alternative form for the hook end.

Figure 3 is perspective view of a 35mm film cassette and tongue end of the film utilizing my film registration device as properly installed in a 35mm camera, Figure 4a is a cross-sectional view of the film drive sprocket and the film takeup spool of a 35mm camera showing a film having the tab of my film registration device installed thereon and in the position prior to winding of the film on the take-up spool, or after partially rewinding the film into the film cassette.

Figure 4b is the film of Figure 4a wound onto the take-up spool showing the flattening of the tab hook in accordance with mv invention Figure 5 is a perspective view of a 35mm film cassette with an alternative implementation of my invention involving formation of a projecting flap hook in the film stock and Figure 6 is a partial view of the operative elements of a tool suitable for forming the flap hook shown in Figure 5.

DETAILED DESCRIPTION OF THE INVENTION The basic elements of a preferred embodiment of my film registration device are a laminated tab 10 and an index mark 22, as shown in Figure 1. Tab 10 consists of a body 12 fabricated from a stiff, yet flexible, plastic material. For example, cellulose acetate and proponate are suitable materials, although many other types of plastic may be used. A thickness of the plastic of 6-10 mils is satisfactory. One end of body 12 is preformed to have an upward curved hook 13, best seen in Figure 2 with dimension A being on the order of 1/16 inch. As may be understood, the use of a suitable plastic for body 12 allows the curved hook 13 to be flattened out under pressure, yet return to its original shape when the pressure is relieved, as will be discussed in more detail hereinafter. Hook 13 is preferably formed by heating and bending the tab end, although cold-forming is suitable for some materials.

An adhesive substrate 14 is disposed on the underside of tab 12 extending the length of the fiat portion thereof. Substrate 14 may be a layer of 1 mil double-sided MYLAR (Registered Trade Mark) pressure-sensitive self-adhesive tape, or, alternatively, may be a coating of adhesive material on the underside of tab 12. The upper surface of tab 12 has a printed decalcomania layer 16 or the like disposed thereon. Layer 16 contains a set of the numbers 1 through 36 (18) printed thereon, as well as index marks 24. The numbers 18 are ofthe ruboff type, and a number may be easily removed by rubbing with the fingernail, pencil eraser, or the like. As an example, number 22 is indicated as having been removed from layer 16.

The size of my device is not critical, although I prefer that the tab 12 be approximately 5/8 inch wide and 1+ inches long. Index mark 22 is preferably formed of a white plastic tape having a self-adhesive backing.

In Figure 2a, a partial side view of the hook-end of the tab 10 is shown, as attached to a film base 11. The laminated construction of the tab 10 can be seen.

Hook 13 is formed as an approximately S-shape. The shape of hook 13 is not critical since its role in accordance with my invention is to contact the cassette light trap and prevent the film from being completely drawn into the cassette during rewind. For example, the wedge-shaped hook 15 of Figure 2b is an alternative shape that provides certain advantages to be described below.

Turning now to Figure 3, a typical installation of tab 10 on a film and the proper installation of the film in a 35mm camera is illustrated. Camera 40 is shown with its back cover 41 (partial view) open.

The tip of film tongue end 36 has been secured in a slot 45 of take-up spool 44 and the film advanced two frames by cocking lever 46.

Sprocket element 42 represents the film drive sprocket fof the typical 35mm camera 40 suitable for using my device and method. As is well known, sprocket 42 is coupled to film advance and shutter cocking lever 4 and the film counter (not shown) when cover 41 is closed. It is common for sprocket 42 to have six teeth 43 for engaging perforations along the edges of film 34 while the length of a frame (36mm) matches eight perforations in the film. To utilize my invention, a film cassette 30 is installed in the camera as shown, and the tongue end 36 of the film strip 34 is inserted in slot 45 of takeup spool 44, engaging the teeth 43 of sprocket 42 with the perforation of tongue 36. Cocking lever 46 is operated to advance the film two frames. Since cover 41 is open, the advancing operation does not cause the film counter to advance.

At this point and as shown by Figure 3, tab 10 is attached to film tongue end 36 by means of the adhesive substrate 14, carefully matching index marks 24 with the two uppermost teeth 43 of sprocket 42.

Although not essential, I prefer to install index mark 22 directly opposite teeth 43, as shown. to make the tab installation more easily performed. Next, back cover 41 is closed and locked, thereby engaging sprocket assembly 42 with the film counter which will indicate an "S" or start position on most cameras. The film may now be advanced to the "O"~ or first exposure point of the film counter. As the film is advanced, the film tongue 36 is wound onto spool 44, and tab 10 (by virtue of its flexibility) easily conforms to the curvature of spool 44. Furthermore, curved end 13 partially flattens without impeding the normal winding of the film. This action is best seen in Figure 4, which shows sprocket 42 and spool 44 in cross-section, with film strip 34, tab 10, and film tongue 36 seen in side view. In Figure 4a, film tongue 36 is shown in the position at time of installation of tab 10 illustrated in Figure 3. As may be seen, hook 13 is in its open position, prior to advancing the film and winding the film onto spool 44.

In Figure 4b, film 34 has been partially wound onto spool 44. As may now be seen, tab 10 does not interfere with such winding due to its flexibility and hook 13 tends to flatten out from the pressure of the wound film.

During the rewind process, when the tongue end 36 of film 34 leaves spool 44, hook 13 springs out to its original shape and the condition of Figure 4a again obtains.

Returning now to the use of the camera after having the film counter set to "O", and with reference to Figure 3 the camera may be used in normal fashion to the point at which the photographer desires to remove the film prior to exposing all of the frames. At this time, the number of the last exposed frame is noted from the frame counter, rewind button 47 is depressed, and the film is rewound into cassette 30. As tongue end 36 of film 34 pulls free from spool 44, hook 13 of tab 10 springs out to its normal shape as discussed above. As may now be seen, continued winding will cause hook 13 to contact light trap 32 of cassette 30, preventing tongue end 36 from being completely rewound into the cassette. In some cameras, end 13 may contact the film pressure plate instead of the light trap 32. In such a case, the camera back is opened, the cassette removed and rewinding completed manually it is for this case that I prefer the wedge-shaped hook 15 shown in Figure 2b. This hook shape will pass under the film pressure plate, yet will be stopped by the cassette light trap.

After completing the rewinding and removing the cassette from the camera, the last-noted exposed frame number is rubbed off of decalcomania substrate 16, advantageously recording this required information for alter use.

At a later time when it is desired to complete the partially-exposed roll of film, camera back cover 41 is opened. The cassette is installed and tongue end 36 is inserted in slot 45 of spool 44. The film 34 is advanced two frames by cocking lever 46 securing the film on spool 44. At this point, tab 10 will be in approximately the same position as at time of original installation. The two index marks 24 are again aligned with the two uppermost teeth of sprocket 42. Spool 44 can be turned against its clutch manually without affecting the position of sprocket 42. Thus, tab 10 index marks 24 can be easily brought into exact alignment with the correctly-matching sprocket teeth 43. Index mark 22 assists in this alignment by virtue of its white surface in contrast with the black camera frame.

The last previously exposed frame is noted from the numbers 18 and the camera back 41 is closed, again engaging the frame counter. As may now be understood, through the use of my film registration device, the frame counter is exactly synchronized with the film driving sprocket element 42, the film strip 34, and its previously exposed frames. The photographer now advances the film by cocking the advance lever 46 and releasing the shutter with a lens cap in place until the counter reads the next unexposed frame, which is one beyond the number indicated on the decalcomania substrate 16. The camera is now ready to expose additional frames of film strip 34.

In accordance with my invention, the photographer is able to accurately register exposed frames with the exposure counter of the camera, and can therefore complete exposure of remaining frames without waste of film. Furthermore, the spacing between earlier exposed frames and later exposed frames will be identical when developed, and can be cut into short lengths with automatic equipment without danger of cutting into a frame.

Having shown a preferred embodiment of my invention, I will now describe alternative implementations that fall within the scope of my invention.

Figure 5 illustrates one alternative implementation which uses a projecting flap or hook 60 formed directly from the film base 51. A rectangular tab is cut on three sides creating opening 61 and flap 60. Flap 60 thus created is bent outward as shown at an acute angle to the plane of the film thus forming a projecting hook.

Opening 61 is cut with its short side immediately adjacent to two sprocket holes 62 and having a length essentially equal to the total length of sprocket holes 62.

Flap hook 60 is utilized in the same fashion as previously described with reference to tab 10.

To install cassette 50 in a camera, the back is opened, film tongue 53 is inserted in the take-up spool slot and the cocking lever advanced to cock the shutter. At this point the take-up spool is turned with the thumb slipping its clutch until sprocket holes 62 will fit over the upper two sprocket teeth. Cassette 50 is then dropped into place, the camera rewind knob engaged, and the rewind turned to take up any slack. The camera back is closed and the camera is ready for use. As film strip 51 is wound on the take-up spool, flap 60 tends to flatten and does not interfere with the rewinding.

As may be noted, no index marks are required for this implementation since sprocket holes 62 provide the necessary reference. After partially exposing film strip 51, the film is rewound, flap 60 will spring out and will catch on either the camera film pressure plate or light trap 56 of cartridge 50.

Before opening the camera to remove cassette 50, the last exposed frame is noted. After removing cassette 50, decalcomania 52, affixed to cassettte 50 and having rub-off numbers 55, is utilized as previously described to note the last exposed frame by erasing the appropriate number. Thus, the cassette is prepared for its next use.

As may be understood, decalcomania 52 may be supplied with a self-adhesive backing for installation on any cassette, or may be printed directly on the cassette at time of manufacture. As may be recognized. this embodiment can be implemented at virtually no cost, yet will greatly extend the usefulness of the cassette.

The implementation of Figure 5 can be added to any film cassette and film strip by means of a forming tool such as partially shown in Figure 7. The tool comprises base 70 having a female die 72 and a row of sprocket-hole engaging teeth 76 positioned to hold film tongue 53 in the desired position for forming tab 60.

The distance from the end of tongue 53 to flap 60 is selected to allow about two turns of film around the take-up spool to bring sprocket holes 62 in proper relation with the drive sprocket teeth in accordance with my invention.

Male die 74, shown in its normal operative position, has cutting edges on the three sides corresponding to opening 61.

The fourth non-cutting side is relieved as shown as is the matching side of the female die 72. Space B as shown is selected to be essentially equal to the thickness of the film stock to be punched. Thus, when male die 74 is forced downward through the film stock, flap 60 will be sharply bent in the desired hook shape.

The tool, partially depicted in Figure 6, can be utilized in automatically operated equipment for use during manufacture of the cassette package, or it can be incorporated in a manual punching configuration for use with purchased cassette packages.

As will be evident to those skilled in the art, various modifications of the specific configurations of my film registration device that I have disclosed are possible without departing from the scope of my invention. For example, the projection on the base side of the film in accordance with my invention can be formed in a number of alternative ways. A shallow dimple or dimples can be pressed into the film and will serve to provide the required mechanical stop, yet not interfere with the winding of the film strip on the takeup spool. Alternative add-on projection can be formed from foam rubber, felt strips, or the like and all such embodiments are considered to fall within the scope of my invention.

While I have characterized the projec tion disposed on the film as a mechanical stop, it is to be understood that a user could, by applying sufficient force to the rewind crank, overcome the stopping action; however, this action is not an intended use of my invention. The resistance felt by the user when the projection contacts the cassette light trap provides ample notice to the user to cease rewinding in accordance with my invention.

WHAT WE CLAIM IS: 1. A film strip for attachment at one end to a film cassette spool for insertion in a camera, the other end being formed as a narrowed tongue portion for engagement with the camera spool, in which the film strip has a projection upstanding from or adjacent the tongued portion for engaging the cassette, in use, to resist winding of the tongued portion thereinto and index means adjacent the projection and aligned with at least one of a plurality of sprocket holes along a longitudinal edge of the film for usein registering the said projection in a given location with respect to the camera sprocket, the projetcion being so formed as to allow the film to be wound on to the camera spool, in use.

2. A film strip as claimed in Claim 1, in which a portion of a generally-rectangular tab of flexible material is glued to the film strip, a free end portion of the tab closer to that end of the strip for attachment to the cassette spool being bent out of the plane of the glued portion along a line substantially perpendicular to the longitudinal axis of the strip to form the projection.

3. A film strip as claimed in claim 2, in which the tab is glued to that side of the film strip not bearing the light sensitive emulsion.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. lever advanced to cock the shutter. At this point the take-up spool is turned with the thumb slipping its clutch until sprocket holes 62 will fit over the upper two sprocket teeth. Cassette 50 is then dropped into place, the camera rewind knob engaged, and the rewind turned to take up any slack. The camera back is closed and the camera is ready for use. As film strip 51 is wound on the take-up spool, flap 60 tends to flatten and does not interfere with the rewinding. As may be noted, no index marks are required for this implementation since sprocket holes 62 provide the necessary reference. After partially exposing film strip 51, the film is rewound, flap 60 will spring out and will catch on either the camera film pressure plate or light trap 56 of cartridge 50. Before opening the camera to remove cassette 50, the last exposed frame is noted. After removing cassette 50, decalcomania 52, affixed to cassettte 50 and having rub-off numbers 55, is utilized as previously described to note the last exposed frame by erasing the appropriate number. Thus, the cassette is prepared for its next use. As may be understood, decalcomania 52 may be supplied with a self-adhesive backing for installation on any cassette, or may be printed directly on the cassette at time of manufacture. As may be recognized. this embodiment can be implemented at virtually no cost, yet will greatly extend the usefulness of the cassette. The implementation of Figure 5 can be added to any film cassette and film strip by means of a forming tool such as partially shown in Figure 7. The tool comprises base 70 having a female die 72 and a row of sprocket-hole engaging teeth 76 positioned to hold film tongue 53 in the desired position for forming tab 60. The distance from the end of tongue 53 to flap 60 is selected to allow about two turns of film around the take-up spool to bring sprocket holes 62 in proper relation with the drive sprocket teeth in accordance with my invention. Male die 74, shown in its normal operative position, has cutting edges on the three sides corresponding to opening 61. The fourth non-cutting side is relieved as shown as is the matching side of the female die 72. Space B as shown is selected to be essentially equal to the thickness of the film stock to be punched. Thus, when male die 74 is forced downward through the film stock, flap 60 will be sharply bent in the desired hook shape. The tool, partially depicted in Figure 6, can be utilized in automatically operated equipment for use during manufacture of the cassette package, or it can be incorporated in a manual punching configuration for use with purchased cassette packages. As will be evident to those skilled in the art, various modifications of the specific configurations of my film registration device that I have disclosed are possible without departing from the scope of my invention. For example, the projection on the base side of the film in accordance with my invention can be formed in a number of alternative ways. A shallow dimple or dimples can be pressed into the film and will serve to provide the required mechanical stop, yet not interfere with the winding of the film strip on the takeup spool. Alternative add-on projection can be formed from foam rubber, felt strips, or the like and all such embodiments are considered to fall within the scope of my invention. While I have characterized the projec tion disposed on the film as a mechanical stop, it is to be understood that a user could, by applying sufficient force to the rewind crank, overcome the stopping action; however, this action is not an intended use of my invention. The resistance felt by the user when the projection contacts the cassette light trap provides ample notice to the user to cease rewinding in accordance with my invention. WHAT WE CLAIM IS:

1. A film strip for attachment at one end to a film cassette spool for insertion in a camera, the other end being formed as a narrowed tongue portion for engagement with the camera spool, in which the film strip has a projection upstanding from or adjacent the tongued portion for engaging the cassette, in use, to resist winding of the tongued portion thereinto and index means adjacent the projection and aligned with at least one of a plurality of sprocket holes along a longitudinal edge of the film for usein registering the said projection in a given location with respect to the camera sprocket, the projetcion being so formed as to allow the film to be wound on to the camera spool, in use.

4. A film strip as claimed in Claim 1,

Claim 2 or Claim 3, in which the free end portion of the tab is folded about a line substantially parallel to the line of bending and in a direction opposite to the direction of bending of the tab.

5. A film strip as claimed in Claim 2, Claim 3 or Claim 4, in which the index means comprise two marks on the glued portion of the tab, aligned with respective sprocket holes in the film.

6. A film strip as claimed in any of Claims 2 to 5 in which the tab is provided with a set of numerals of from one to at least the number of film frames of the strip, the individual numerals being readily removable.

7. A film strip as claimed in Claim 1, in which the projection comprises a rectangular flap portion of the film strip which is bent out of the plane of the strip along a line substantially perpendicular to the longitudinal axis of the strip, forming an aperture in the strip extending from the said line towards that end of the strip for attachment to the cassette, the index means being formed by the edges of the said aperture.

8. A film strip as claimed in Claim 6 or Claim 7, in which the flap portion is inclined at an acute angle to the plane of the aperture where the flap portion adjoins the film strip.

9. A film strip as claimed in claim 1 and substantially as herein described with reference to, and as shown in, Figures 2 to 4 or 5 of the drawings.

10. A photographic film cassette incorporating a film strip as claimed in any of Claims 1 to 9.

11. A photographic film cassette incorporating a film strip as claimed in Claim 7 or Claim 8 and having a set of numerals of from one to at least the number of film frames of the film strip on an external face thereof, the individual numerals being readily removable.

12. A photographic film cassette as claimed in claim 11 and substantially as herein described, with reference to, and as shown in, Figure 5 of the drawings.

13. A method of modifying a film strip attached at one end to a film cassette spool for insertion in a camera, the other end being formed as a narrowed tongued portion for engagement with a camera spool, in which an at-least-partially-collapsable projetcion is formed on or adjacent the tongued portion for engaging the cassette, in use, to resist winding of the tongued portion thereinto, the projection being collapsable to allow winding of the film on to the camera spool, and in which index means are formed simultaneously adjacent the projection in alignment with at least one of a plurality of socket holes along a longitudinal edge of the film for use in registering the said projection in a given location with respect to the camera sprocket.

14. A method as claimed in Claim 13, including the steps of: cutting a flap in the tongued portion of the film strip so that a free end of the flap is closer to that end of the film strip attached to the cassette spool and an edge of the flap is located adjacent at least one sprocket hole to form said index means; and bending the flap out of the plane of the film strip on that side of the film strip not bearing the light-sensitive emulsion.

15. A method of modifying a film strip as claimed in claim 13 and substantially as herein described with reference to Figures 5 and 6 of the accompanying drawings.