Film changer for x-ray diagnostic apparatus using bare film sheets

Claim 1

Film changer for X-ray diagnostic apparatus, using bare film precut into sheets and comprising a first housing subdivided into three compartments by means of two symmetrically spaced walls, each having a narrow first slot for allowing the transfer of film sheets between said compartments ; the lateral ones of said compartments alternately and respectively forming : a film supply section for containing a supply of unexposed film sheets and a storage section for storing exposed ones and the middle one of said compartments forming an exposure and transfer section for succcessively transferring said unexposed film from said supply section and locating them in position for exposure and for transfering said exposed film sheets to said storage section ; said lateral compartments respectively containing two identical electrically controlled removable magazines and respectively comprising two first electrical connector means for delivering supply voltages to and signals from said magazines, having a plurality of contacts ; each of said magazines comprising a light-tight second housing provided with an elongated narrow second slot for the introduction of said film sheets therein and their ejection therefrom, one by one, and including within said second housing : flexible means made up from a band of plastic material ; a motor-driven supply spool for containing a supply of said flexible means, whose one extremity is fixed thereto ; a motor-driven storage spool for storing said film sheets thereupon between two faces of said flexible means, whose other extremity is fixed to said storage spool substantially located at the center of said housing, said supply and storage spools having respective shafts parallel to said slot ; a pair of contiguous cylindrical rollers parallel to and located close to said slot for light-tightly shielding said magazine, said flexible means, between said supply and said storage spool, passing around one roller of said pair and between both of then, whereby to guide said film sheets to be stored, from said slot towards said storage spool and/or those to be ejected from said storage spool towards said slot ; first electrical motor means for respectively driving said supply and storage spools ; second electrical connector means having a plurality of contacts mounted on said housing for interconnection with said first connector means ; rotary signalling means having a shaft coupled to that of one of said spools and fed by one of said supply voltages for delivering a first signal to a first one of said contacts when said storage spool is empty and a second signal to a second one of said contacts when said storage spool is full ; electrically operated bistable switching means for indicating whether the film contained therein is exposed or unexposed, said switching means being made up by a polarized relay with magnetic latching so as to remain in any one of its stable states without being fed by a control voltage ; said relay being set into its first state by means of a control voltage applied to a third contact of said connecting means while being charged with unexposed film for delivering a third signal indicating the presence thereof to a fourth contact and reset into its second state by means of said first signal when it becomes empty for delivering a fourth signal indicating the emptyness or the presence exposed film sheets to a fith contact ; said exposure and transfer section including motor-driven means for transporting said film sheets and second Electrical motor means for driving said transporting means ; said film changer further comprising means for simultaneously electrically controlling the operation of said first and second electrical motor means, electrically connected to said two first connector means and said second motor means for receiving said first second, third and fourth signals from both of said magazines and for delivering supply voltages to said first and second motor means, said rotary signalling means and said bistable switching means and including : logic circuit means fed by said signals for discriminating between the magazines which contain exposed or unexposed film and which are full or empty ; switching means controlled by said logic circuit means for inverting the direction rotation of said first and second motor means in accordance with the content of said magazines, whereby said film changer is rendered reversible.