Method and apparatus for coin discrimination utilizing a coin impeller

Abstract

A method of coin discrimination and a coin discriminator are disclosed which utilize a coin impeller, the impeller comprising magnetic field means for accelerating each coin to a velocity primarily dependent upon the coin's characteristics of electrical conductivity and density, for discriminating among coins based upon the trajectory of the accelerated coin.

I claim: .[. 
     
       1.  A method of determining the acceptability of coins comprising the steps of generating a traveling magnetic field, directing a coin to the magnetic field so that the force of the field impels the coin projecting it in a desired direction and accepting the coin only if it has a trajectory characteristic of a desired coin..]. 
     
     
       2. The method of claim .[.1.]. .Iadd.3 .Iaddend.wherein desired coins are sorted in accordance with their characteristic trajectories. 
     
     
       3. The method of .[.claim 1.]. .Iadd.determining the acceptability of coins comprising the steps of generating a traveling magnetic field, directing a coin to a coin support track in the magnetic field so that the force of the field impels the coin along the coin support track projecting it in a desired direction and accepting the coin only if it has a trajectory after it leaves the coin support track characteristic of a desired coin, .Iaddend.further comprising the step of making a preliminary classification of the coin and wherein as a result of that classification a value of a characteristic of the magnetic field is selected. 
     
     
       4. The method of claim 3 wherein the preliminary classification is the result of an examination of chordal dimension. 
     
     
       5. The method of claim 3 wherein the rate of change of the magnetic field is selected. 
     
     
       6. The method of claim 3 wherein the strength of magnetic field is selected. 
     
     
       7. The method of claim 3 wherein the characteristic is selected to project all acceptable coins through one or more acceptance windows at a single location. 
     
     
       8. The method of claim 2 further comprising the .[.steps.]. .Iadd.step .Iaddend.of .[.making a preliminary classification of the coin and as a result of the classification.]. establishing an acceptance window .Iadd.as a result of the classification .Iaddend.on the trajectory of the desired coins of that classification. 
     
     
       9. The method of claim 8 wherein the preliminary classification is the result of an examination of chordal dimension. 
     
     
       10. The method of .[.claim 1.]. .Iadd.determining the acceptability of coins comprising the steps of generating a traveling magnetic field, directing a coin to a coin support track in the magnetic field so that the force of the field impels the coin along the coin support track projecting it in a desired direction and accepting the coin only if it has a trajectory after it leaves the coin support track characteristic of a desired coin, .Iaddend.further comprising the steps of initially causing the magnetic field to travel in a direction .Iadd.along the coin support track .Iaddend.opposed to the direction of coin projection, stopping the coin and causing the field to travel in the direction of coin projection. 
     
     
       11. The method of claim 10 further comprising the steps of making a preliminary classification of the coin while the coin is stopped and as a result of that examination selecting a predetermined impelling force of the magnetic field. 
     
     
       12. The method of claim 10 further comprising the steps of making a preliminary classification of the coin while the coin is stopped and as a result of that classification establishing an acceptance window on the trajectory of the desired coins of that classification. .[.13. Apparatus for determining the acceptability of coins comprising traveling magnetic field producing means arranged to impel a coin and thereby project it into a trajectory, means for directing a coin to the magnetic field and means defining an acceptance window on the trajectory characteristic of a desired coin..]. .[.14. The apparatus of claim 13 further comprising a coin support from which coins are projected..]. .[.15. The apparatus of claim 14 further comprising means defining a plurality of acceptance 
     
     
        windows, each on a trajectory characteristic of a desired coin..]. 16. The apparatus of .[.claim 14.]. .Iadd.for determining the acceptability of coins comprising a coin support track for supporting a coin on its edge, traveling magnetic field producing means arranged to impel a coin along the coin support track and thereby project it from the coin support track into a trajectory, means for directing a coin to the magnetic field and means defining an acceptance window on the trajectory characteristic of a desired coin, .Iaddend.further comprising means for making a preliminary classification of the coin and producing a signal indicative of the classification and means responsive to the signal for selecting a value of 
     
     
        a characteristic of the magnetic field. 17. The apparatus of claim 16 wherein the means for making the preliminary classification comprises a 
     
     
        chordal dimension sensor. 18. The apparatus of claim 16 wherein the value selecting means comprises means for selection of the rate of change of the 
     
     
        magnetic field. 19. The apparatus of claim 16 wherein the value selecting means comprises means for selecting the magnitude of the power supplied to 
     
     
        the field producing means. 20. The apparatus of claim 17 wherein the value selecting means comprises means for selection of the rate of change of the 
     
     
        magnetic field. 21. The apparatus of claim 17 wherein the value selecting means comprises means for selection of the magnitude of power supplied to 
     
     
        the field producing means. 22. The apparatus of claim 16 wherein the value selection means are arranged to select a value of a characteristic of the magnetic field such that at least two varieties of desired coins are projected on trajectories passing through one or more acceptance windows 
     
     
        at a single location. 23. The apparatus of claim .[.14.]. .Iadd.16 .Iaddend.wherein the means for producing a traveling magnetic field is a 
     
     
        linear impeller. 24. The apparatus of claim 23 further comprising a source of alternating current, start control means for connecting the current source to the linear impeller, and a zero-crossing detector connected to monitor the current source and connected to enable the start control 
     
     
        means. 25. The apparatus .[.of claim 14.]. .Iadd.for determining the acceptability of coins comprising a coin support track for supporting a coin on its edge, traveling magnetic field producing means arranged to impel a coin along the coin support track and thereby project it from the coin support track into a trajectory, means for directing a coin to the magnetic field and means defining an acceptance window on the trajectory characteristic of a desired coin, .Iaddend.further comprising means for causing the magnetic field to travel in either of two opposed directions along the coin support track and a coin stop in the direction of travel 
     
     
        opposed to the direction of projection. 26. The method of claim 25 further comprising at least one chordal dimension sensor adjacent the coin stop. 
     
     
          . The apparatus of claim .[.14.]. .Iadd.16 in which the means defining an acceptance window comprises at least one movable barrier in the region into which coins are projected and means for moving the barrier .Iadd.responsive to an initial denomination determination. .Iaddend.