DEVICE FOR CENTERING X-RAY FILM CASSETTES

Abstract: In a device for centering X-ray film cassettes (19) of different sizes by means of two parallely guided bars (10, 12) movable towards each other and away from each other respectively in a cassette unloading and loading machine, a symmetrical lever arrangement (6, 7, 8) for moving the bars (10, 12) is provided which is actuated by means of a rod hinged to it and shiftable by a motor. The rod consists of two linearly movable connected portions (4 and 5) which are urged apart in opposite directions by a spring (9) and which are shifted together when the bars (10, 12) abut on the side walls of a cassette. Due to this arrangement, the impact of the abutment of the bars (10, 12) is absorbed and a switch (3) for arresting the motor, which is arranged on portion (4) is actuated in a first section of the path of shifting movement and an overtravel of the motor compensated in a second section of the path of shifting movement.

Description: Device For Centering X-Ray Film Cassettes The invention relates to a device for centering X-ray film cas¬ settes of different sizes by means of two parallely guided bars movable towards and away from each other respectively in a cas¬ sette loading and unloading apparatus. A centering device of this type is known (US-PS 3,150,263). That centering device is associated with a feeding means located in a cassette unloading and loading machine for transporting an X-ray film cassette from an unloading and loading position. The known centering device comprises a first pneumatically reciprocating crank disk and a second crank disk operatively connected with that first disk and rotatable in the opposite direction. Each crank disk is associated with a bar via a pair of parallely pivotable links. According to another cassette positioning device (DE-OS 30 00 760) the shifting movement of a bar is effected by means of a motordriven worm gear spindle. Both devices are disadvantageous in that the centering and align¬ ment of an X-ray film cassette is effected by an abrupt and un- absorbed impact of the bars which abut on the side walls of the cassette and in that in the case of the motor drive of the last- mentioned device, an overtravel of the motor cannot be compen¬ sated. Moreover, in the case of the first-mentioned device. X-ray film cassettes of larger sizes can only be precisely and reliably aligned and centered by means of an additional slider engaging the rear end of the cassette and transporting the X-ray film cas¬ sette over the last portion of its path up to its unloading and loading position. It is the object of the invention to provide a centering device of simple construction and reliable and precise operation in which the impact of the bars abutting on the side walls of the cassette is attenuated and wherein the motor drive moving the bars is switched off at a given point and the overtravel of the motor compensated. In accordance with the invention this object is attained in that a symmetrical lever arrangement is provided for moving the bars, said arrangement being actuated by means of a motorically slid- able rod hinged to it and consisting of two portions movable towards each other and in that a switch for arresting the motor is arranged in the path of movement of at least one of said portions. According to a useful modification a friction clutch formed by a spring is connected with the two portions such that they are urged apart in opposite directions. In detail the invention provides that the two portions are held together so as to be linearly shiftable, that when the bars abut on an X-ray film cassette, the portions are shifted together in opposition to the force of a spring and that the path of shifting movement is dimensioned such that the switch is operated in a first section and an overtravel of the motor compensated in a second section of the path. The advantage attained by the invention consists in that as a result of the resiliently shiftable rod portions, the impact of the bars abutting on the side walls of the cassette is absorbed and the X-ray film cassette is aligned and centered with an atten¬ uated movement. During that operation the cassette is precisely aligned and positioned free from play between the spring-biased bars. The motor drive is arrested while the rod portions are still being shifted together and an overtravel of the motor is compensated. According to a further useful modification, the length of the bars corresponds at least to the length of the sides of an X-ray film cassette of maximum size, and the bars are shiftably guided on a guide rod as well as on guide rails, their free ends extend¬ ing into the interior of the apparatus and being provided with guide grooves. An embodiment of the invention is illustrated in the drawings and will be described in further detail below. In the drawings Figs. 1 and 2 show a plan view of the subject matter of the invention in two functional positions, Fig. 3 shows a detail of the subject matter according to Fig. 2 in a sectional view along line II-II, Figs. 4 and 5 show plan views of a detail of the subject matter according to Figs. 1 and 2 in two func¬ tional positions, and Fig. 6 shows a sectional view along line IV-IV of a detail of the subject matter according to Fig. 4. In an apparatus 1 for unloading exposed film sheets from X-ray film cassettes of different sizes and for loading said cassette with unexposed film sheets, a device for centering the X-ray film cassette is provided in the area of the unloading and loading station. This centering device comprises two parallely guided bars 10 and 12 movable towards each other and away from each other respectively, said bars being moved by means of a transport belt 15 which transports an X-ray film cassette 19 from an input point to the unloading and loading station. The transport belt 15 is placed around two spindles 14, one of which is driven. In ,the present embodiment, the X-ray film cassette 19 illustrated is of small size. As can be seen from Figs. 1 to 3, the bars 10 and 12 are mounted to angle plates 11 and 13 by means of screws 17. Each angle plate 11 and 13 respectively is shiftably mounted by means of a guide sleeve 11a and 13a respectively on a guide shaft 16 secured be¬ tween two mounting angles If of the apparatus. The ends of the bars 10, 12 which extend into the interior of the apparatus are provided with guide grooves 10a.and 12a. By means of said guide grooves, the bars 10 and 12 are additionally guided for sliding movement on guide rails lb arranged in an intermediate wall la of the apparatus. The numeral le denotes a guide ramp for the cassettes, which is located on the intermediate wall la, and the numeral Id two cassette abutments fastened to said intermediate wall. A symmetrical lever arrangement located between the two bars 10 and 12 serves to actuate said bars. The lever arrangement con¬ sists of a two-arm lever 6 mounted centrally about a stationary pin 6c. At one free lever end 6a, a first lever arm 7 is hingedly connected which points to the right and at the other free lever end 6b a second lever arm 8 is hingedly connected which points to the left. The free ends 7a and 8a of the two lever arms 7 and 8 are hingedly connected to the angle plates 11 and 13 supporting the bars 10 and 12. A drive motor 2 is screwed to a mounting angle lc of the appara¬ tus. The free end 4a of a portion 4 of a rod consisting of two portions 4 and 5 movable towards each other is linked to a crank disk 2a seated on the motor shaft and rotatable by the motor in the two directions of the arrows "A' r and "B" (Figs. 1 and 2). The other free end 5a of portion 5 of the rod directly engages the hinge between lever 6 and the lever arm 8 which points to the left. As can be inferred in particular from Figs. 2 and 4, the two » portions 4 and 5 of the rod are connected so as to be linearly shiftable According to the embodiment, a switch 3 is arranged in the middle of portion 4. The half of portion 4 to the right of switch 3 is U-shaped and serves to accommodate the left half of portion 5 which is provided with two-pin-and-slot guide arrange¬ ments 5b. As shown in Fig. 6, pins 18 are inserted or screwed into the lower part 4d of the U-shaped half of portion 4, said pins extending through the pin-and-slot guide arrangements 5b of portion 5 and through bores in the upper portion 4b of the U-shaped half of portion 4. A spring 9 is hooked with one end to a tongue 4c of portion 4 and with its other end to a bent-off portion 5c of portion 5. It forms a friction clutch holding the two portions 4 and 5 apart in opposite directions. In this initial position (Figs. 1 and 4) one part of the bent-off portion 5c rests loosely on the button of switch 3. When an X-ray film cassette 19 is transported from the input point to the unloading and loading station, motor 2 is switched on by switch means not illustrated in detail when the front side of the cassette contacts one of the abutments Id, the motor actu¬ ating the symmetrical lever arrangement 6, 7 and 8 by means of crank disk 2a rotating in the direction "A" as well as the rod hinged to it. The bars 10, 12 are thereby moved from the initial position shown in Fig. 1 towards each other. When the bars 10, 12 abut on the side walls of the cassette, the portions 4 and 5 of the rod are shifted together. The path of shifting movement is restricted to a length such that switch 3 is actuated and motor 2 switched off in a first path section "a" and the overtravel of the motor compensated in a second path section "b". At the same time, this slight shifting together of the two portions 4 and 5 of the rod absorbs the impact of the bars 10 and 12 abutting on the side walls of the cassette.

Claims: Patent Claims 1. Device for centering X-ray film cassettes of different sizes by means of two parallely guided bars movable towards and away from each other respectively in a cassette unloading and loading apparatus, c h a r a c t e r i z e d in that a symmetrical lever arrangement (6, 7, 8) is provided for moving the bars (10, 12), said arrangement being actuated by means of a motorically slidable rod hinged to it, and consis¬ ting of two portions (4, 5) movable towards each other and in that a switch (3) for arresting the motor (2) is arranged in the path of movement of at least one of the portions (4, 5) . 2. Device according to claim 1, characterized in that a friction clutch formed by a spring (9) is connected with both portions (4, 5) such that they are urged apart in opposite directions. 3. Device according to claims 1 and 2, characterized in that the two portions (4, 5) are held together such that they can be linearly shifted, in that when the bars (10, 12) abut on an X-ray film cassette (19) , the portions (4, 5) are shifted together in opposition to the force of spring (9) and in that the path of shifting movement is dimensioned such that switch ^ 3 ) is actuated in a first section "a" of the path and an overtravel of the motor is compensated in a second section "b" of the path. 4. Device according to claim 1, characterized in that the length of the bars (10, 12) corresponds at least to the length of the sides of an X-ray film cassette of maximum size, in that the bars (10, 12) are shiftably guided on a guide rod (16) and, with their free ends extending into the interior of the apparatus and provided with guide grooves (10a, 12a), are also shiftably guided on guide rails (lb).

Inventors: KILLGUSS HEINRICH, MIRLIEB BERND, KILLGUSS, HEINRICH, MIRLIEB, BERND
Applicants: EASTMAN KODAK CO, KODAK AG, EASTMAN KODAK COMPANY, KODAK AKTIENGESELLSCHAFT
Application year: 1988
Main classification: G03B42
IPC codes: F16H21, G03B42