US3792766A

US3792766A - Magnetic coin eliminator

Info

Publication number: US3792766A
Application number: US00266375A
Authority: US
Inventors: G Fougere
Original assignee: Mars Inc
Current assignee: Mars Inc
Priority date: 1972-06-26
Filing date: 1972-06-26
Publication date: 1974-02-19
Anticipated expiration: 1991-02-19

Abstract

What is disclosed is a magnetic coin eliminator for removing from a passageway coins having a magnetic permeability to density ratio in excess of a predetermined value, the eliminator including a magnetic means which has a magnetomotive force sufficient to effect substantially horizontal movement of the coin while the coin is supported vertically in the passageway but which force is insufficient to support the coin when the passageway support is removed resulting in the coin falling from the eliminator.

Description

llnited States Patent 1191 Fougere 1451 Feb. 19, 1974 Primary ExaminerStanley I-I. Tollberg Assistant Examiner-David A. Scherbel Attorney, Agent, or FirmDavis, Hoxie, Faithful &

Hapgood [57] ABSTRACT What is disclosed is a magnetic coin eliminator for removing from a passageway coins having a magnetic permeability to density ratio in excess of a predetermined value, the eliminator including a magnetic means which has a magnetomotive force sufficient to effect substantially horizontal movement of the coin while the coin is supported vertically in the passageway but which force is insufficient to support the coin when the passageway support is removed resulting in the coin falling from the eliminator.

12 Claims, 2 Drawing Figures III 1/ 11/1 11 MAGNETIC COIN ELIMINATOR This application is a continuation of U.S. Pat. application No. 66,126 filed Aug. 21, 1970, which in turn is a continuation of U.S. Pat. application No. 808,943

filed Mar. 20, 1969, both now abandoned.

This invention relates to coin selectors which determine the authenticity and denomination of coins and, more particularly, to an improved magnetic coin eliminator which is utilized in such coin selectors for removing magnetic coins from the coin selector shortly after the coin enters the selector.

Many coin selectors, indeed most, utilize a magnetic field as part of the apparatus for determining the authenticity and denomination of coins entering the selector. As the coin travels through a coin passageway in the selector it passes through the magnetic field where the coin velocity is retarded in proportion to the ratio of the electric conductivity to density of the material constituting the coin, the ratio being hereinafter referred to as the coins acceptance ratio. If a magnetic coin, such as the Canadian nickel, or a slug, having a ratio of magnetic permeability to density in excess of a predetermined value is fed into the coin selector, the coin or slug will become lodged in the magnetic section of the selector and the machine will be unusable until the coin or slug is cleared. Clearing of the coin or slug requires specialized equipment and circuitry which increases the expense of the selector and provides an additional area which is subject to malfunction.

To eliminate these problems, it is well-known to employ a permanent magnet located adjacent to the beginning of the coin passageway for the purpose of removing magnetic coins or slugs having a magnetic permeability above a predetermined value. These wellknown devices require relatively complicated and often unreliable means for removing the coins from the magnet which add to the expense and complexity of the coin selectors.

Briefly stated, this invention, in one form, provides a magnetic coin eliminator formed of an electromagnet or permanent magnet attached to the armature of a solenoid. The poleface of the magnet which resides adjacent to the coin passageway is covered by a thin plate of plastic material having a very low coefficient of friction. The combination of the thickness of the plastic plate and the magnetic pole strength is chosen to provide an effective magnetic attractive force sufficient to move the magnetic coin substantially horizontally while the coin is supported in the vertical direction by the floor of the passageway; however, the force is insufficient to support the coin vertically against gravitational forces which are exerted on the coin when it has been moved off of the passageway floor. As soon as the solenoid moves the magnet and coin a sufficient distance to remove the coin from the passageway, the coin slides off of the plastic plate and drops vertically into a coin rejection slot.

The objectives and advantages of the improved magnetic coin eliminator of this invention will be better appreciated and understood from the detailed description below and the drawing in which:

FIG. 1 is an elevational sectional view of a magnetic coin eliminator formed in accordance with a first embodiment of this invention employiny a permanent magnet, and

FIG. 2 is an elevational sectional view of a magnetic coin eliminator formed in accordance with second embodiment of this invention employing an electromagnet.

Referring now to FIG. 1, there is illustrated a magnetic coin eliminator 10 designed to be utilized with a 7 coin selector for determining the authenticity and denomination of coins which enter the selector. These types of selectors are used primarily in combination with vending machines. The coin selector is provided with a coin passageway 12 formed in part by a pair of spaced

housing walls

14, 15 and a coin support platform or track 16. The track 16 is canted slightly in order to cause a coin passing through the passageway to lean against one of the walls, wall 15. A coin 18 entering the system is brought to rest adjacent to the coin eliminator 10 by any conventional stop means, such as a solenoid controlled arrestor pin 19. For simplicity of discussion, the term coin as used throughout this specification is intended to include any item which is fed into the selector, such as authentic coins, counterfeit coins, and slugs, such as washers, discs, etc.

The wall 15 toward which the coin is canted is provided with an aperture 20 having a diameter at least equal to the diameter of coin entrance slot (not shown) or, in other words, at least equal to the largest diameter coin which can enter the passageway 12. Pivotally attached to the wall 15 by means of a bracket 24 is a support arm 26 and pivotally attached to the support arm 26 near the middle thereof is a solenoid 28 having an armature 30.

A permanent magnet 32 having a pole face facing the passageway ,12 is attached to the end of the support arm 26 remote from the pivotal mounting bracket 24. A thin plate 34 of plastic material having a low coefficient friction, such as polytetrafluoroethylene (Teflon), is bonded to the pole face of the magnet 32. The magnet 32 and plastic plate 34 normally lie adjacent to the coin passageway 12 and the plastic plate actually resides slightly within the aperture 20 through the side wall 15. I

A coin 18 entering the selector rolls down through the passageway 12 on the track 16 until it is brought to rest adjacent to the magnetic coin eliminator 10. If the coin 18 has a magnetic permeability in excess of a predetermined value, the coin will adhere to the plate 34 due to the magnetomotive force. The combination of the strength of the magnet 32 and the thickness of the plastic plate 34 are such as to provide a magnetomotive force sufficient to effect substantially horizontal movement of the magnetic coin but insufficient to provide a frictional force sufficient to support the coin with respect to gravitational forces. After the coin has arrived at a position in the passageway 12 opposite the aperture 20 the arrestor pin 19 is removed and the solenoid 28 is actuated by suitable conventional control circuitry 35 causing the solenoid armature 30 to move away from the passageway 12 effecting retraction of the magnet 32 and plate 34 from the passageway 12. The control circuit 35 includes a coin sensor such as a micro-switch and a timer to control the time of actuation of the pin solenoid and magnet solenoid. A coin which has a magnetic permeability to density ratio less than the predetermined value does not adhere to the plastic plate 34 and rolls down the passageway 12. If the magnetic permeability to density ratio of the coin 18 is above a predetermined value, the coin adheres to the plastic plate 34 and, as the magnet 32 and. plate 34 move away from the passageway 12, the coin 18 slides transversely along the track 16 until it reaches a position just beyond the edge of the track 16. At the instant the coin travels beyond the track 16, gravitation force is exerted on the coin 18 which is no longer supported vertically by the track. Since the attractive force of the magnet combined with the low coefficient of friction of the plate 34 does not establish a high enough frictional force to support the coin against the gravitional force, the coin drops from the magnet into a coin rejection slot 36.

In the second embodiment illustrated in FIG. 2 the magnetic coin eliminator 50 is designed to be effective with large heavy coins of low magnetic permeability as well as small light coins of high magnetic permeability.

One of the problems with using a permanent magnet, as described in the first embodiment above, is if the magnet is strong enough to remove a heavy coin having a relatively low magnetic permeability, small light coins having a high magnetic permeability might become so firmly attached to the magnet that they would not fall off when exposed to the gravitational force while not being supported by the track 16. To eliminate this problem, a conventional, C-shaped electromagnet 52 having a magnet coil 53 is attached to the lower end of a support arm 54. A plastic plate 56 is attached to the face of the magnet 52 facing inwardly toward the coin passageway 12, the plastic plate being of a material having a low coefficient of friction. A solenoid 58 having an armature 60 is pivotally attached to the support arm to provide motion to the magnet 52 and plate 56.

As described above, when a coin 18 having a magnetic permeability to density ratio in excess of predetermined value reaches a position in the passageway contiguous to the magnetic coin eliminator 50 and is brought to rest by arrestor pin 19 it is attracted toward the magnet 52 and held against the plate 56. After the coin is brought to rest the control circuit 35 actuates the arrestor pin solenoid which retracts the arrestor pin 19 and it also actuates the magnetic coin. eliminator solenoid 58 which retracts the solenoid armature 60 away from the passageway 12 resulting in the movement of the magnet 52 away from the passageway 12 and causing the coin 18 to slide along the track 16 until it is beyond the edge of the track. If the coin is heavy enough to overcome the friction force due to the magnetomotive force and coefficient of friction of the plate 56 it will slide off of the plastic plate 56 down into the coin rejection slot 36. However, if the coin is too light to fall on its own accord, one way to cause the coin to fall from the magnet is terminate or sufficiently reduce the magnetic force by terminating the current through the magnet coil 53. This requires a switching circuit and control circuit which adds to the complexity of the device. In place of the circuits for terminating flow of cur-' rent through the magnet coil 53, a C-shaped, soft iron shunt 62 having a magnetic permeability and ahigh saturation flux density is fixedly mounted behind the electromagnet 52 such that, when the magnet 52 is retracted by the solenoid 58, it will bear against the shunt 62. The shunt establishes a relatively low reluctance magnetic path around the rear side of the electromagnet 52 the side which is remote from the passageway 12, which substantially reduces the magnetomotive force on the front side of the magnet. The reduction in the magnetomotive force on the front side of the magnet 52 permits even the lightest coin to slide from the plastic plate 56 down into the coin rejection slot 36. To even further assure that the coin will become released from the magnet 52 after it passes beyond the edge of the track 16, as the electromagnet moves toward the shunt 62 the magnetic forces between the magnet 52 and the shunt 62 cause the magnet 52 to impact against the shunt tending to shake the coin or other material that is attached to the plastic plate 56 loose so that the coin will fall into the coin rejection slot 36.

As can be seen, the above described magnetic coin eliminators are inexpensive to construct and are highly effective for the removal of coins or slugs having a magnetic permeability to density ratio in excess of a predetermined value. The second embodiment (FIG. 2) has the additional advantage of being effective regardless of the size or weight of the coin, or strength of the magnetic attraction between the magnet and the coin. Furthermore, the effective strength of the magnetomotive force can be varied simply by varying the electricalinput to the coil. This permits variation of the predetermined value of the ratio of magnetic permeability to density to suit different applications of the magnetic coin eliminator.

I claim:

I. A magnetic coin eliminator for removing a coin having a ratio of magnetic permeability to density within a predetermined range from a coin passageway having a coin support track of a coin handling apparatus comprising, coin engaging magnetic means including a coin engaging face, and means for moving the coin engaging magnetic means from a first position adjacent the coin support track to a second position spaced horizontally from the track, the strength of the field of the magnetic means a. being sufficient to move the coin with the coin engaging magnetic means from the first position in which the coin is supported vertically by the track to the second position in which the coin is free of the track, and

b. being insufficient in the second position to support a coin engaging the face and free of the track, thereby allowing the coin to fall.

2. A magnetic coin eliminator as defined in claim 1 including a surface of low coefficient of friction on the magnetic means to facilitate separation of the coin from the magnetic means when the coin is free of the track.

3. A magnetic coin eliminator as defined in claim 2 wherein the material having the low coefficient of friction is polytetrafluroethylene.

4. A magnetic coin eliminator as defined in claim 1 wherein the coin engaging magnetic means includes an electromagnet.

5. A magnetic coin eliminator as defined in claim 4 wherein the face of the electromagnet includes a surface of low coefficient of friction.

6. A magnetic coin eliminator as defined in claim 1 wherein the coin engaging magnetic means includes an electromagnet.

7. A magnetic coin eliminator as defined in claim 1 wherein the means for moving is a solenoid having an armature to which the coin engaging magnetic means is attached.

8. A magnetic coin eliminator as defined in claim 1 including means for reducing the magnetic field strength of the coin engaging magnetic means substantially when the coin engaging magnetic means is in the second position.

9. A magnetic coin eliminator as defined in claim 7 including magnetic shunt means which reduces the magnetic field strength of the coin engaging magnetic means when in the second position.

10. A magnetic coin eliminator as defined in claim 9 wherein the shunt means is made of material having high magnetic permeability and a high saturation flux density, the coin engaging magnetic means being adjacent the shunt means when in the second position.

11. A magnetic coin eliminator as defined in claim 10 wherein the coin engaging magnetic means impacts against the shunt means when the electromagnet arrives at the second position to jar coins to facilitate removalof adhered coins.

12. For use in a coin selector, a magnetic coin eliminator for removing a coin having a ratio of magnetic permeability to density within a predetermined range from a coin passageway having a coin support track for supporting vertical coins, comprising coin engaging magnetic means including magnetic means having a coin engaging face of a predetermined coefficient of friction and means for moving said coin engaging magnetic means from a first position adjacent the coin support track in which a coin to be removed is caused to abut the coin engaging face by the magnetic means to a second position in which a coin to be removed in abutment with said face is moved away from said coin support track, the magnetic field of said magnetic means being sufficient to retain the coin to be removed in abutment with said face as the coin and said coin engaging magnetic means are moved from said first position, and the magnetic field and said coefficient of friction being correlated to release the coin to fall when moved to said second position.

$32 3"? UNITED STATES PATENT (JP-mm CERTIFICATE OF CORRECTION Patent 3 v Dated February 19 .1974

Inventofls) GUY L. FOUGERE It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 5, Claim 9, line 1, "claim 7" should be -claim l-- Signed and sealed this 3rd day of December 1974.

(SEAL) Att t:

C. MARSHALL DANN Commissioner of Patents McCOY M. GIBSON JR. Attesting Officer

Claims

1. A magnetic coin eliminator for removing a coin having a ratio of magnetic permeability to density within a predetermined range from a coin passageway having a coin support track of a coin handling apparatus comprising, coin engaging magnetic means including a coin engaging face, and means for moving the coin engaging magnetic means from a first position adjacent the coin support track to a second position spaced horizontally from the track, the strength of the field of the magnetic means a. being sufficient to move the coin with the coin engaging magnetic means from the first position in which the coin is supported vertically by the track to the second position in which the coin is free of the track, and b. being insufficient in the second position to support a coin engaging the face and free of the track, thereby allowing the coin to fall.

11. A magnetic coin eliminator as defined in claim 10 wherein the coin engaging magnetic means impacts against the shunt means when the electromagnet arrives at the second position to jar coins to facilitate removal of adhered coins.