Abstract: A toothed sprocket wheel provides an idler for driving test tube holders into and out of sharp turns which occur in the track of an automatic sample changer employed in radiopharmaceuticals. The sprocket is provided with a selected number of well-defined teeth and is rotatably mounted at the center of a relatively sharp turn so as to transfer the linear motion from the test tube holder at its point of entry into the turn to the test tube holder at the point of exit from the turn. Also disclosed is a tensioner or positioner in a substantially linear alignment of the test tube holders such that, upon varying the degree of insertion of the sprocket teeth between successive test tube holders, the relative spacing between successive test tube holders, and the overall test tube holder train length may be adjusted to compensate for expansion/contraction of the holders due to environmental conditions.

Abstract: Disclosed is an automatic sample changer having a planar upper surface for supporting a continuous chain of test tube conveying pucks. The test tubes being carried by the pucks contain samples such as gamma ray emitting biological samples. A spocket drive gear pulls the pucks into a counting station where the test tubes being carried by the respective pucks are sequentially lowered into a detector region for analysis. After each count is completed, the sample test tube is returned to the surface, and is pushed out of the counting station when the next successive tube-carrying puck is pulled therein. Also disclosed is a disposal site whereby test tubes can be disposed of once the sample has been analyzed, an elevator for lowering and raising the tubes, and a mechanism for enabling the interruption of a long counting operation so as to admit a short count sequence.

Abstract: Disclosed is an automatic sample changer for sequentially operating on a plurality of samples housed in test tubes, circulated around a continuous track, and sequentially associated with a radiation counting device by way of an elevator mechanism. The continuous track is in modular form, and is designed, respectively, to accommodate fifty, one hundred, two hundred or three hundred samples. Rotating index wheels are employed to drive the samples around the track, with several index wheels being used for the longer tracks. The motors controlling the respective index wheels are reversible, and when more than one motor is employed, the motors may be operated in parallel.Also disclosed is a mechanism for loosely coupling the index wheels to their associated motors to facilitate repair and ensure accurate alignment with the plane of the continuous track.

Abstract: An automatic sample changer particularly suited for use in counting biomedical samples from in vitro tests using radiopharmaceuticals such as the technique of radioimmunoassay. A plurality of samples, such as gamma ray emitting samples housed in test tubes, are automatically circulated around a continuous track and are sequentially associated with a radiation counting device by way of an elevator mechanism. A single rotating driving wheel is effective in moving one hundred samples independently travelling on the continuous track. Also disclosed is a breakaway safety mechanism associated with the elevator, and means for detecting and signaling jams in the track and elevator.