US2114638A - Light seal - Google Patents

Description

April 1938. J. H. s. PARKER 2,114,638

LIGHT SEAL Filed Feb. 1'7, 1937 J. Henry S. Parker IN V E NTOR.

ATTORNEYS Patented Apr. 19, 1938 UNITED STATES FATENT OFFICE LIGHT SEAL Application February 17, 1937, Serial No. 126,243

4 Claims.

This invention relates to photography and particularly to light seals for holders for light-sensitive photographic material.

One of the objects of my invention is to provide a light seal of fabric which is rugged in construction and which is effective in preventing light rays from passing to sensitive material held by the holder. Another object of my invention is to provide a light seal of relatively coarse and strong material which is arranged in a plurality of rows of tufts, these tufts being so positioned that light passing through certain of the tufts will be blocked by other tufts of the material. Another object of my invention is to provide a light lock including at least one strip of tufted fabric, the rows of tufts being arranged in parallel and staggered relation. Still another object of my invention is to provide a fabric light lock which is not too resistant to material passing through the light lock opening. A still further object of my invention is to provide a suitable light lock for plate holders, film packs or the like.

Coming now to the drawing, wherein like reference characters denote like parts throughout:

Fig. 1 is a perspective view of a typical film. pack utilizing a light lock constructed in accordance with and embodying a preferred form of my invention.

Fig. 2 is an enlarged fragmentary detail section taken through the light lock passageway for the film pack tabs of the film pack shown in Fig. 1.

Fig. 3 is a perspective view with parts broken away showing a typical plate holder provided with a light-tight passageway utilizing the tufted material of my invention.

Fig. 4 is a fragmentary detail View on a greatly magnified scale showing a portion of a preferred form of the tufted material utilized in making the passageways for light-sensitive material light-tight.

Fig. 5 is a fragmentary enlarged sectional view of the material shown in Fig. 4.

Figs. 6 and '7 show additional types of tufted material which are suitable for use in connection with my invention.

In holders for light-sensitive photographic material, such as plate holders, film packs and the like, it is necessary to provide a passageway from the inside to the outside of these holders for the reception of dark slides or film pack tabs or other parts which must be manipulated before exposing films in the holders. It has previously been proposed that a plush material may be used for rendering such passageways light-tight, but it has been extremely difficult, if not impossible, to obtain suitable material which has a sufficiently thick nap to prevent light from passing through and which at the same time will not take a definite set after being used, so that upon continued use, light may enter.

It is desirable to have a material which is comparatively rugged and stiff, so that it will stand a lot of bending and compression without becoming distorted, but such material is almost always so coarse that light can pass through. With most of the equipment on the market the space provided for the light-tight passageway is limited by the size of the holder, and it will be recognized that particularly on film and plate holders for small-sized or miniature apparatus, the lightlocking material is greatly limited in size so that the width of the light-locking strip cannot be increased beyond a predetermined amount in order to insure added light safety.

My invention broadly comprises making a light-tight passageway through a light-sensitive photographic material holder by providing at least one strip of tufted fabric, the tufts of which may be arranged in rows, and, if desired, the rows may be parallel but in different spaced relation one to the other. Any one row of tufts on this material is not, in itself. light-tight because each individual tuft is shaped more or less like a truncated cone with the small end down, and because of the fabric holding the tufts, it is difficult, if not impossible to space the tufts close enough together to prevent light from entering. However, by staggering the tufts, two or more rows will make a satisfactory light-tight covering which may be placed on one or both sides of the passageway.

I have found that a wool-tufted material is quite desirable because the wool fibers do not readily break off or lose their resilience, and because I have been able to obtain a special weave of such tufted material which fully answers my purpose.

In Fig. l I have shown a typical type of film pack designated broadly as l which may comprise the usual metal or cardboard container 2, the walls being substantially rectangular in shape. One wall 3 is in the form of a frame 4 which makes an exposure frame through which exposures, are made on films attached to tabs 5 which pass through the passageway 53.

The film pack may be of any well-known construction and in Fig. 2 I have illustrated a typical form of light trap for such film packs, but have equipped this light trap with the tufted fabric of my invention. The film pack tabs 5 may pass out through the light trap E which is formed between spaced walls I and 8 of the film pack and in this instance, on both sides of the passageway I provide strips of tufted material 9 and ID. The fabric of the material II and I2 may be cemented in place or may be held in by the bentover metal walls l3 and I 4.

Regardless of how the material is held in, the tufts l5 best shown in Fig. 5, are more or less in the shape of truncated cones with the small ends l8 next to the fabric backing II.

It is customary, but not essential, to weave this material by having two tufts I5 pass through the material with a connected U-shaped twisted part l8 passing through the fabric connecting the tufts. After these have been woven through the fabric, the top may be clipped off at the desired height.

With reference to Fig. 4, it will be seen that while the rows E9 of tufts may be arranged in parallel relation transversely of the strip, they are staggered or offset with respect to other rows of the material, so that even though light may pass through one row, since the tufts are spaced apart at their small ends near the fabric, another row of tufts will block off light passing downwardly in the direction shown by the arrows in Fig. 4.

It is also possible to have material woven with the rows of tufts at an angle to the edge of the material, such as, for instance, is shown in Fig. 6. Here the tufts are diagrammatically illustrated at 25 and the arrangement is such again that light passing downwardly in the direction shown by the arrows will be prevented, before passing through many rows, from penetrating the tufwd material any material distance.

It would be quite desirable if the tufts could be arranged in staggered relation over all the material, as indicated in Fig. 7, so that the tufts 35 would not be in parallel rows or in any regular order. While such material can be woven, it is extremely expensive and, therefore, from the practical standpoint, it is of comparatively little use.

In Fig. 3 I have shown a typical plate holder 5| having an exposure frame 52 which may be normally covered by the usual dark slide 53. Across the top of the plate holder there may be the usual fiange 5 5 for making a light-tight connection with the camera in which it is placed. In plate holders, there are usually two passageways 55 through which dark slides 53 may pass, since plate holders of this type are usually of the double variety. In order to make a light trap which will prevent light from passing through this passageway when the dark slide 53 is removed for exposing the light-sensitive material, I provide one or more strips of tufted material 56 which may be of the above described varieties to contact with the dark slide or the walls of the passageway.

With film packs and to a less extent with plate holders, it is desirable to have a light trap which does. not materially retard the passage of material through the passageway. In filrnv packs, the paper tabs 5 pass through the passageway and it is desirable to have them move as freely as possible, and yet it is also necessary to have a light trap which absolutely prevents light from passing through the opening. With tufted material made as above described, I have found that the tabs slide very readily and that the light locking prop erties are excellent.

Plate holders, of course, are used for a much longer time than film packs and consequently the light locking material is subjected to long continued wear. With tufted material constructed as above described, I have found that these light locks retain their efficiency over long periods of time, because the individual tufts or brush-like members seem to bend and spring back into place quite readily, this being particularly true because the tufts can move somewhat like a plurality of small brushes.

It is obvious that my invention is suitable for any types of holders in which photographic lightsensitive material is used. Such material, of course, may be plates, cut films and film packs, regardless of the type of base that the light-sensitive emulsion may be coated upon. Where I have referred to light-sensitive material in the specification and claims, I intend to include all of the well-known types of emulsion-coated bases.

What I claim as my invention and desire to be secured by Letters Patent of the United States is:

1. In a holder for light-sensitive photographic material, the combination with a casing, of an exposure frame carried by the casing, means for holding light-sensitive material therein, walls included in the casing spaced apart and forming a passageway extending through the casing, and a light trap for said passageway comprising at least one strip of tufted material comprising a plurality of rows of tufts, said tufts being so arranged with respect to the edges of the light trap opening that light passing through the tufts of one row may be blocked by the tufts of another row, the tufts of one row being offset with respect to the tufts of another row, said material com prising a wool pile fabric, the individual strands of which are comparatively tough and having a series of the individual strands made into tufts, thereby holding the individual strands upwardly from a fabric base.

2. In a holder for light-sensitive photographic material, the combination with a casing, of an exposure frame carried by the casing, means for holding light-sensitive material therein, walls included in the casing spaced apart and forming a passageway extending through the casing, and a light trap for said passageway comprising at least one strip of tufted material comprising a plurality of parallel rows of tufts, said tufts of one row being staggered with respect to the tufts of another row whereby light which may pass between the tufts of one row may be blocked by the tufts of another row, said material comprising a wool pile fabric, the individual strands of which are comparatively tough and having a series of the individual strands made into tufts, thereby holding the individual strands upwardly from a fabric base.

3. In a holder for light-sensitive photographic material, the combination with a casing, of an exposure frame formed in one wall of the casing, means for holding light-sensitive material behind the exposure frame, said casing walls including a passageway through the casing through which tabs attached to the light-sensitive material may pass, and a light trap for said passageway including at least one strip of a tufted material having the tufts thereof arranged in staggered relation to prevent light passing between certain tufts from passing through said light trap, said tufts pressing against the tabs passing through said passageway, said material comprising a wool pile fabric, the individual strands of which are comparatively tough and having a series of the in dividual strands made into tufts, thereby holding the individual strands upwardly from a fabric base.

4. In a holder for light-sensitive photographic material, the combination with a casing, of an exposure frame formed in one wall of the casing, means for holding light-sensitive material behind the exposure frame, said casing walls including a passageway through the casing through which tabs attached to the light-sensitive material may pass, and a light trap for said passageway including at least one strip of a tufted fabric having the tufts arranged in a plurality of rows, the tufts of one row being spaced differently from the tufts of another row whereby openings between the individual tufts of one row may be covered by the tufts of another row and light rays are prevented from passing through the passageway, said material comprising a wool pile fabric, the individual strands of which are comparatively tough and having a series of the individual strands made into tufts, thereby holding the individual 10 strands upwardly from a fabric base.

J. HENRY S. PARKER.

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