X-ray or gamma ray systems or devices – Photographic detector support – Sheet film cassette
Patent
1991-01-28
1992-09-08
Church, Craig E.
X-ray or gamma ray systems or devices
Photographic detector support
Sheet film cassette
378187, G03B 4204
Patent
active
051464845
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
The invention relates to a sheet-film cassette comprising a lower cassette portion serving to position the sheet film, an upper cassette portion forming the cassette lid and including sheet-film pressure means, a narrow side wall connected to said lower portion, said upper cassette portion being held to said side wall, and thereby to said lower cassette portion, by a hinge, said hinge extending in a direction parallel to said side wall and having a surface aligned with the outer surface of said side wall, one part of the hinge being connected to the side wall, a second part of the hinge being connected to the upper cassette portion, the cassette also having a closing device which is arranged on the side of the cassette opposite to said hinge, the hinge further comprising a first projection, which extends from the part of the hinge connected to the side wall in a direction parallel with the hinge and projects into the interior of the cassette, a second projection which extends from the part of the hinge connected to the upper cassette portion in a direction parallel with the first projection and projects into the interior of the cassette.
In a cassette of this type which has been disclosed in DE-C1-34 01 577the cassette lid is hinged to the lower cassette portion by a hinge made of flexible material and comprising a pivot zone formed by a thinned section and having two claw-like holding elements to connect the cassette portions.
According to another cassette (PCT-A1-WO 82/00900) the cassette lid is hinged to the lower cassette portion by a plastic hinge, a flexible pivot zone being formed by a thinned section of the material at the hinge. The hinge is fastened to a thin wall of the lower cassette portion which in a manner known per se serves for positioning the cassette and for moving an X-ray film into close contact with a portion adapted to receive said film.
As a result of the thin wall of these cassettes and the thinned flexible zone of their hinges, the stability of these cassettes in the area of the hinge is reduced so that uniform contact pressure of the film cannot be guaranteed.
It is the object of the invention to provide a sheet-film cassette of the generic type such that in the area of the cassette hinge, too, a uniform contact pressure by a cassette lid on the film is reached over the whole length of the hinge.
In accordance with the invention this object is attained in that when the cassette is closed the second projection engages the first projection from below, whereby the projections support each other.
Avantageously, the hinge consists of a flexible material and has a ledge-shaped profile with a pivot zone formed by a thinned section of the material. Holding elements extending in the longitudinal direction on either side of said pivot zone are provided for the cassette portions as well as for the projections required for the support according to the invention and for further elements provided for light-sealing purposes.
As a result of the design of the sheet-film cassette according to the invention, the cassette, which is unstable in the area of the thin wall and the pivot zone of the hinge when in its open position, is stabilized when the cassette is closed. Thus the cassette lid and its pressure means respectively can exert uniform pressure on the film across the whole length of the hinge.
Further features and advantages can be inferred from the description of an embodiment of the invention illustrated in the drawings and from the subclaims.
The drawings show schematically in
FIG. 1 a lateral view of a sheet-film cassette;
FIG. 2 a plan view of the cassette according to FIG. 1, and
FIG. 3 a sectional view along line A--A in FIG. 2, with only the essential areas illustrated and shown in section respectively.
The invention will be described with reference to an X-ray sheet-film cassette which is preferably used for mamographic purposes and to this end is designed with a relatively thin end wall so that the Xray film can be moved as closely as possible to the body.
The cassette
REFERENCES:
patent: 4637043 (1987-01-01), Bauer
patent: 5086446 (1992-02-01), Bauer et al.
Church Craig E.
Eastman Kodak Company
Pincelli Frank
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