Patent Publication Number: US-4926998-A

Title: Coin senser for pay telephone

Description:
INFORMATION DISCLOSURE STATEMENT 
     In pay, or coin operated telephones, it is necessary that there be some means to determine how many of what denomination coins have been deposited into the telephone. For this purpose, telephones include a slug rejector, or coin sorter, to separate the various denominations of coins to be delivered to separate chutes. In each chute, then, some means is provided to determine the presence or absence of a coin. Since each chute receives only one denomination of coin, the additional information of how many coins have passed through each cute allows an easy calculation to arrive at the total dollar value deposited. 
     The prior art coin sensers have normally included solid state equipment for detection of the presence of a coin. One of the most commonly used devices includes a light emitting diode (LED) and a sensor such as a phototransistor. Usually, the LED is chosen to operate in the infrared area to minimize false readings. Other systems utilize Hall-effect switches or the like. It has been found that the use of these solid state sensers is undesirable in that the life is rather short. Realizing that the apparatus is continually bombarded by coins, ranging from relatively light dimes to rather heavy quarters, and such a mechanical beating destroys solid state components. In spite of the constant destruction which requires replacement of the sensing apparatus, the solid state sensers remain the most-used sensing means. 
     SUMMARY OF THE INVENTION 
     This invention relates generally to sensing apparatus, and is more particularly concerned with a coin sensing device for use in pay telephones and the like. 
     The present invention provides a circuit block that receives the coins from the coin sorter, the circuit block including a plurality of pins so arranged that a coin in a coin chute must necessarily engage at least one pin. In one embodiment of the invention, two pins are used, and the coin completes a circuit between the two pins. In another embodiment of the invention, only one pin is used for each chute, and the coin completes a circuit between the pin and the chute itself. In each embodiment, the pin occupies a sufficient portion of the chute that the coin for that chute cannot avoid engaging the pin or pins in such chute. 
     The pins comprising the sensing mechanism are sufficiently durable that the present invention should remain serviceable for many years. Though the present invention requires use of electronics, the electronics are removed from the area of bombardment by coins so that solid state integrated circuits and the like are not harmed by use of the device. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other features and advantages of the present invention will become apparent from consideration of the following specification when taken in conjunction with the accompanying drawings in which: 
     FIG. 1 is a perspective view of a coin sorter for use in pay telephones and the like, the coin sorter having a coin senser made in accordance with the present invention installed therein; 
     FIG. 2 is an enlarged, fragmentary right side elevational view of the coin sorter shown in FIG. 1, and illustrating the printed circuit control board for the device; 
     FIG. 3 is an enlarged fragmentary cross-sectional view taken through some of the chutes of the coin sorter and showing the senser of the present invention; and, 
     FIG. 4 is a view similar to FIG. 3 but showing a modified form of senser made in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Referring now more particularly to the drawings, and to those embodiments of the invention here presented by way of illustration, FIG. 1 shows a coin sorter generally designated at 10 and having a coin slot 11 for receiving coins to be deposited. The body 12 of the coin sorter 10 includes means for checking the size and weight of coins in order to separate coins by denomination. Such devices usually reject improper deposits, or slugs, at the same time. Such mechanisms are well known in the art, and no detailed description is thought to be necessary. 
     After the coins are sorted in the body 22 of the mechanism 10, each denomination of coins is directed to one chute such as the chutes 14 and 15. Those skilled in the art will understand that a coin sorter designed to receive four different denominations of coins will have four such chutes, and coin sorters designed to receive different numbers of denominations will have a different number of chutes. 
     Once the coins are in the chutes such as the chutes 14 and 15, there must be some means for detecting the presence of the coins in order to count the coins and, ultimately, determine the total dollar value of coins deposited. However, it should be realized that the coins are sorted and placed into the individual chutes 14 and 15, and the coins are falling after passing the various sorting mechanisms. It is because of the distance the coins fall that the prior art detecting apparatus is damaged over a period of time. With the present invention, too, the coins fall and engage a block 20 that stops the fall of the coins. 
     The block 20 of the present invention is preferably made of a plastic material such as nylon, polyolefin, or pehaps high impact polystyrene or the like. The important feature in selecting a plastic is sufficient resilience to prevent fracturing under continual bombardment of the coins. The block 20 extends completely across the body 12, and includes a plurality of pins 21 for engaging the coins. Circuit means 22 connect the pins 21 to a circuit board 24. 
     As is shown in FIG. 2 of the drawings, one side of the coin sorter 10 mounts a conventional printed circuit board 24 having a plurality of integrated circuits 25 thereon. The integrated circuits (IC&#39;s) are in the form of dual-in-line-packages (DIP) and may comprise any circuitry required. Wires 26 connect the circuit means 22 to the printed circuit board 24. 
     Looking now at FIG. 3 of the drawings, the block 20 is shown extending across the two chutes 14 and 15. In the embodiment of the invention illustrated in FIG. 3, the pins 21 comprise pairs of pins designated at 21a and 21b. The electrical arrangement is such that a coin, such as the coins 28 and 29, electrically connect the two pins 21a and 21b to complete a circuit and allow detection of the coin. In providing for the arrangement it is important that the pins 21a and 21b be so located and arranged that a coin will always contact the pins but will never engage the top of either pin, which would cause the coin to bounce upwardly. 
     To assure that a coin cannot engage the top, or upper end of a pin 21a or 21b, the pins 21a and 21b include heads that are generally conical in configuration, the apex of the cone being outside the chute 14 or 15. As a result, only the sloped surface of the head of the pin is presented to the coin. Preferably, the pins 21a and 21b are so placed that the coin 28 cannot pass between the pins 21a and 21b while the pins are straight. Rather, the coin 28 will forcefully engage the heads of the pins 21a and 21b and cause the pins to bend aside and allow the coin to fall. This is illustated with the coin 29, the coin 29 being shown engaging the block 21, and the pins 21a nd 21b being shown bent outwardly. This assures that the pins 21a and 21b will engage the coin 29 sufficiently to make a good electrical contact, and absorb some of the energy of the falling coin. The showing in the drawing is exaggerated for ease in understanding. 
     As before, the block 20 includes circuit means 22 which s connected to various required circuits in the manner shown in FIG. 2. Specifically, the pins 21a and 21b are connected to a debounce circuit 30. Those skilled in the art will understand that almost any mechanical switch inherently has a certain amount of bounce in making and breaking, and circuits to minimize the electrical effects are well known. The debounce circuit 30 may be any of the well known debounce circuits such as a 555 timer. 
     Attention is next directed to the embodiment of the invention shown in FIG. 4 of the drawings. This embodiment is similar to the previous embodiment discussed and the like parts carry the same reference numerals. It will therefore be seen that there are two chutes 14 and 15, and a block 20 having circuit means 22 connected to a debounce circuit 30. Coins 28 and 29 are shown in the chute 14 and 15 engaging the pins 21. 
     In FIG. 4 of the drawings, the pins 21 are designated as 21c. It will be noticed that there is only one pin 21c for each chute 14 and 15, the pins 21c being angled across the chutes 14 and 15 so that a coin 28 or 29 must necessarily engage the pin 21c. As before, it is important that the coin cannot engage the end of the pin 21c to cause a pin to bounce up. The extending ends of the pins 21c are therefore beyond the chutes 14 and 15, and are in the confines of the walls of the chutes. 
     Since two electrical contacts are required to complete a circuit, the embodiment of the invention illustrated in FIG. 4 uses the metallic walls of the chutes 14 and 15 as the second contact. The angular disposition of the pins 21c insures that the coin 28 or 29 will slide towards the wall of the chute 14 or 15, so the coin will firmly engage both a pin 21c and a wall of a chute. The debounce circuit is then connected between the circuit means 22 and the wall of the chute 14 and 15. 
     It will therefore be understood from the foregoing discussion that the present invention provides a very simple mechanical arrangement for detecting the presence of a coin. The apparatus is not delicate, and can withstand the continual shock of falling coins without damage to the device since the circuit devices are removed from the sensing area. It will of course be realized by those skilled in the art that the particular embodiments of the invention here presented are by way of illustration and are meant to be in no way restrictive; therefore, numerous changes and modifications may be made, and the full use of equivalents resorted to, without departing from the spirit or scope of the invention as outlined in the appended claims.