GB2096354A

GB2096354A - X-ray film cassette

Info

Publication number: GB2096354A
Application number: GB8209504A
Authority: GB
Original assignee: Philips Gloeilampenfabrieken NV
Current assignee: Koninklijke Philips NV
Priority date: 1981-04-04
Filing date: 1982-03-31
Publication date: 1982-10-13
Also published as: CA1168074A; IT1150516B; IT8220547A0; DE3113793A1; JPS57178234A; FR2503398B1; FR2503398A1; GB2096354B

Abstract

An X-ray film cassette (1) comprises a lid (5) pivotable on a lower portion (4). The film (21) is held between an upper pressure plate (9) which is fixed to the inner side of the lid and which incorporates an intensifier screen (9a) on its lower side, and a lower pressure plate (22, 23) which is pivotable on the bottom (7b) of the cassette. When the lid is opened the film and lower pressure plate are together urged downwardly away from the upper pressure plate and intensifier screen and upwardly away from the bottom of the cassette by springs (28 and 27) to bring the film to a position in which a projecting edge portion of the film can be gripped between transport rollers (25) for withdrawal of the film from the cassette. <IMAGE>

Description

SPECIFICATION X-ray film cassette The invention relates to an X-ray film cassette, comprising a storage space for an X-ray film which is situated between a bottom and a lid which is pivotably connected thereto, the cassette comprising a locking mechanism which defines the mutual position of the bottom and the lid in the open as well as in the closed condition of the cassette, the cassette comprising spring means which retain the X-ray film in a fixed position with respect to the bottom and the lid in the closed condition of the cassette and which release the Xray film for transport from the cassette in the open condition of the cassette.

For the unloading of a known X-ray film cassette of the kind set forth (British Patent Specification 1,454,750), the cassette is coupled, with its side which is to be opened directed downwards, to a film development apparatus which also opens the cassette. To this end, the Xray film should become loose in the cassette so that it drops between transport rollers of the film development apparatus under the influence of gravity.

It is a drawback of the known X-ray film cassette that it cannot be unloaded in the horizontal position. A further drawback consists in that after the opening of the cassette, the X-ray film is liable to adhere to an intensifier screen contacted under pressure by the X-ray film in the closed condition of the cassette.

It is an object of the invention to provide an Xray film cassette in which said drawbacks are mitigated.

To this end, an X-ray film cassette in accordance with the invention is characterized in that the bottom of the cassette comprises at least one spring which brings the X-ray film in the vicinity of its transport position, the lid comprising at least one spring for disengaging a combination consisting of the X-ray film and a film pressure plate from a further film pressure plate, connected to the lid, and an intensifier screen, the dimensions of the X-ray film being larger than the dimensions of the film pressure plate, an edge region of the X-ray film thus remaining free to be engaged by transport means.

An embodiment of the invention will be described in detail hereinafter with reference to the drawings. Therein: Figure 1 is a longitudinal sectional view of an X-ray film cassette in accordance with the invention, and Figure 2 is a perspective view of a part of the X-ray film cassette shown in Figure 1.

The X-ray film cassette 1 whose opening side is placed in a defined position in the figures (at the right) during loading and unloading, for example, by pressing against an abutment 3 (see Figure 2) by means of a spring 2, comprises a lower portion 4 and a lid 5. The lower portion 4 comprises a peripheral rectangular U-profile 7a which has an open upper side and which is closed in a lighttight manner in the downwards direction by a bottom 7b. The lid 5 comprises a rectangular cover plate 6a which is enclosed by a wall 7 which is perpendicular to the plate. In the closed condition of the cassette, the wall 7 is situated between the U-profile 6 and the U-profile 7a, so that a so-called labyrinth is formed and ingress of light is precluded (see figure 2).The lid 5 is pivotably connected to the lower portion 4 by means of a hinge 8 which is secured to the lower portion 4 and to the lid 5 opposite the opening side of the cassette (i.e. at the left in Figure 1). A plate-shaped member 9 of an elastic material, for example, a foamy plastics is connected to the inner side of the lid 5, the side of said member which faces the lower portion 4 of the cassette comprising an intensifier screen 9a (see Figure 1) whereagainst an X-ray film 21 is pressed in the closed condition of the cassette.

For the opening and closing of the cassette, a locking mechanism is provided between the Uprofile 6 and the U-profile 7a on each of the two oppositely situated sides (the figures show only the front mechanism), said locking mechanism comprising a slide 9c which is coupled to an arm 10 which is pivotably connected to the lid 5 and the slide 9c. When the slide 9c is displaced, the lid is opened or closed. To this end, two guide pins 11 and 12 (Figure 2) which are rigidly connected to the lower portion 4 engage in two slotted holes 1 3 and 14 of the slide 9c. Therefore, the slide 9c can be displaced only in the direction perpendicularly to the pivot axis of the lid. When the cassette is closed, the slide 9c is slid forwards (to the right in Figure 2) by a spring 15, a locking cam 1 6 on the front end of the slide 9c then engaging behind a pin 1 7 on the lid 5.

For the opening of the cassette, each of the two pins 1 8 (only one of which is shown in Figure 2), is slid into an opening 26 in the U-profile 7a, for example, by means of a pneumatic drive cylinder, so that the slide 9c is moved from the opening side towards the pivot axis of the lid 5 against the force of the spring 15. During this movement, first a pin 19 which is mounted on the arm 10 is displaced in a further slotted hole 20 in the slide 9c until the pin 19 contacts the right end wall of the slotted hole 20, the lid 5 being pivoted upwards about the axis of the hinge 8 when the slide 9c is displaced further.

In the closed condition of the cassette, the Xray film 21 is situated in the part of the lower portion 4 which is enclosed by the U-profile 6 and rests on a pressure plate (22, 23) which comprises a plate-shaped body 22 of, for example, a foamy plastics which is glued on to a plate 23. The plate 23 is pivotable at the left-hand side (in a manner not shown for the sake of clarity) about an axis which is parallel to the pivot axis of the lid 5. The film pressure plate consisting of the plate 23 and the plate-shaped body 22, preferably comprising an intensifier screen (not shown), is shorter than the X-ray film 21, so that at the right-hand side (Figure 1) of the X-ray film an edge region 23a remains which does not bear on the pressure plate (22, 23).

Between the lower portion 4 and the pressure plate consisting of the parts 22 and 23 there are provided spring means which comprise several blade springs 27, so that in the opened condition of the cassette the pressure plate (22, 23) is pivoted forwards, with the result that the pressure plate and notably the projecting edge region (23a) of the X-ray film 21 disengage from the bottom 7b of the lower portion 4 or the lid 5. The freely projecting edge region 23a of the X-ray film 21 can then be readily engaged by a set of transport rollers 25. The rotatable transport rollers 25 are arranged on a preferably wedge-shaped positioning device 24 which can be introduced, guided by the lower portion 4, into the opening side of the cassette so that the pressure plate (22, 23) is placed in a defined position in which the Xray film 21 extends exactly between the two transport rollers 25.

In order to prevent the X-ray film 21 from adhering to the intensifier screen 9a, connected to the pressure plate 9, when the cassette is opened, the portion of the lid 5 which is situated opposite the edge region 23a of the X-ray film comprises a helical spring 28 which presses against the edge region 23a and which ensures that the X-ray film 21 indeed disengages from the intensifier screen 9a. Because in the closed condition of the cassette the edge region 23a of the X-ray film is not contacted by the pressure plates (9; 22, 23) or the intensifier screens 9a present thereon, the edge region 23a is (substantially) not exposed during an X-ray exposure. This offers the advantage that patient data or other data can be recorded on the edge region 23a in a further station. In order to prevent direct exposure of the X-ray film 21 to gamma quanta, the lid 5 may be covered with a lead plate at the area of the edge region 23a.

In the same position in which the cassette is unloaded by removal of the X-ray film, it can be loaded again by introduction of another X-ray film. For this purpose it is merely necessary to reverse the drive direction of the transport rollers 25.

Claims

1. An X-ray film cassette, comprising a storage space for an X-ray film which is situated between a bottom and a lid which is pivotably connected thereto, the cassette comprising a locking mechanism which defines the mutual position of the bottom and the lid in the open as well as in the closed condition of the cassette, the cassette comprising spring means which retain the X-ray film in a fixed position with respect to the bottom and the lid in the closed condition of the cassette and which release the X-ray film for transport from the cassette in the open condition of the cassette, characterized in that the bottom of the cassette comprises at least one spring which brings the Xray film in the vicinity of its transport position, the lid comprising at least one spring for disengaging a combination consisting of the X-ray film and film pressure plate from a further film pressure plate, connected to the lid, and an intensifier screen, the dimensions of the X-ray film being larger than the dimensions of the film pressure plate, an edge region of the X-ray film thus remaining free to be engaged by transport means.

2. An X-ray film cassette substantially as herein described with reference to the accompanying drawings.