Patent Number: 042119286
Section: claims

1. In radiographic apparatus for manipulating a quantity of radioactive material between a stored position and a use position including a capsule of said radioactive material, a storage unit with means defining a passage through it, for storing the capsule in the passage and shielding the surrounding environment from the stored radioactive material, and manipulating means connectible to said storage unit at a first end of said passage for moving said capsule between a stored position within the passage and a use position outside the second end of said passage, the improvement comprising: a shutter mounted on said storage unit for sliding movement transverse to the second end of said passage between first and second limits, said shutter in said first limit blocking said second end, said shutter having a hole through it which registers with said passage when the shutter is in said second limit, shutter-retaining means associated with said passage means adjacent said second end and resilient means cooperating with said retaining means and said storage unit for urging said retaining means to project an end-part toward said shutter, means in said shutter for receiving said end-part when said shutter is in said second limit and thereby retaining said hole in register with said passage, and means coupled to said capsule for pulling said retaining means away from said shutter against the action of said resilient means under control of said manipulating means for withdrawing said end-part from said receiving means and thereby permitting said shutter to move toward said first limit. 2. Apparatus according to claim 1 including operator means to move said shutter from said first limit to said second limit, said operator means including a tell-tale to indicate visually that said shutter is in one or the other of said limits. 3. Apparatus according to claim 1 wherein said hole is sized to permit said capsule to pass to a use position outside of said storage unit. 4. Apparatus according to claim 1 wherein said shutter retaining means is a tubular member fitted telescopically within said passage means, said resilient means cooperates with said tubular member and said passage means to project an end-part of said tubular member toward said shutter, and said receiving means is an annular recess surrounding said hole, said tubular member having an internal diameter substantially the same as the diameter of said hole. 5. Apparatus according to claim 4 wherein said tubular member has an external flange at said end-part and an internal flange at its other end, said resilient means comprises a coil spring surrounding said tubular member and exerting force on said external flange, and a plug within said tubular member is coupled to said capsule for cooperating with said internal flange for withdrawing said end-part from said annular recess. 6. Apparatus according to claim 1 including resilient means for urging said shutter toward said first limit. 7. Apparatus according to claim 1 including latch means for retaining said shutter in said first limit, and means to release said latch means to free said shutter to be moved toward said second limit. 8. Apparatus according to claim 7 wherein said release means comprises an element extending forward of said storage unit from said second end of said passage. 9. Apparatus according to claim 1 including a nipple fitted to said storage unit at said second end of said passage, for receiving a coupling element of guide tube means for said capsule, latch means for retaining said shutter in said first limit, and means operable by said coupling element upon attachment to said nipple to release said latch means to free said shutter to be moved to said second limit. 10. Apparatus according to claim 9 wherein said release means comprises an element extending forward of said storage unit from said second end of said passage into a position adjacent said nipple, for interaction with said coupling element.