GB2055498A

GB2055498A - Coin selection device

Info

Publication number: GB2055498A
Application number: GB8022821A
Authority: GB
Original assignee: Nippon Conlux Co Ltd
Current assignee: Nippon Conlux Co Ltd
Priority date: 1979-07-17
Filing date: 1980-07-11
Publication date: 1981-03-04
Also published as: GB2055498B; DE3026880A1; FR2466055A1; IT8023420A0; JPS5616276U; IT1131563B

Abstract

A Coin selection device for discriminating the coin diameter is of a type in which an oscillating coil 12a and a receiving coil 12b are disposed on opposite sides of a coin path 10. Both coils 12a, 12b are disposed towards the top of the coin path 10. The size I of the coils 12a, 12b is substantially the same as the difference in diameter between the coin of largest diameter A and that of smallest diameter B to be handled by the device. Such an arrangement enables the size of a coin to be discriminated with high accuracy. <IMAGE>

Description

SPECIFICATION Coin selection device This invention relates to an electronic coin selection device for a vending machine employing an oscillating coil and a receiving coil and, more particularly, to an electronic coin selection device capable of discriminating diameters of deposited coins.

Known in the art of a vending machine is a coin selection device which comprises an oscillating coil and a receiving coil provided in a coin path and discriminates material or size of a coin by variation in the level of a received signal produced by passing of the coin. In the prior art device, the oscillating coil and the receiving coil both have a size which is sufficiently longer than the coin diameter. When a coin has entered an electromagnetic field produced between the oscillating coil and the receiving coil, a different level in the received signal is produced depending upon the size, i.e. diameter, of the entire coin. It is known that the higher the oscillating frequency is, the more convenient it is for the examination of the coin diameter.If, for example, the oscillating frequency is of the order of 100 kHz, the level of a received signal depends principally on the coin diameter irrespective of the material of the coin. If, however, the oscillating frequency is of the order of 10 kHz, the level of the received signal depends mainly on the material of the coin. Since the size of the coils in the prior art device is such that it covers the entire coin, the size of the entire coin influences the level of the received signal and difference in the coin diameter is represented as only a slight difference in the level of the received signal. Difference in the diameter between different sorts of coins is only a matter of about one tenth of the coin diameter.As will be apparent from Fig. 1, difference in the level of the received signal which is produced by difference d (= Da - Db) in diameters of coins A and B is of a small magnitude if compared with an entire level of the received signal. The portion H indicated by a broken line in Fig. 1 represents the size of the prior art coin selection device. Hence, it was difficult in the prior art coil type coin selection device to discriminate the coin diameter.

It is, therefore, an object of the present invention to provide an electronic type coin selection device eliminating the above described disadvantage of the prior art coin selection device.

According to the invention, there is provided a coin selection device capable of accurately discriminating the coin diameter in which the size of the oscillating and receiving coils is made substantially the same as difference in the diameter between a coin of the largest diameter and that of the smallest diameter. The device is so constructed that a coin falls along the lower side of the coin path and difference in the diameter between coins appears on the upper edge of the coin path. The coils are provided in the vicinity of the upper edge so that the difference in the level of the received signal caused by the difference in the coin diameter will be indicated at a relatively large ratio to the entire level of the received signal.

Fig. 1 is a diagram for illustrating the fact that only a small difference in the level of a received signal results from the difference in the coin diameter according to the prior art device; Fig. 2 is a side view of a coin path in the embodiment of the invention; Fig. 3 is a perspective view of the coin path; and Fig. 4 is a graphical diagram showing results of measuring levels of received signals with respect to two coins of different diameters in a case where coils are provided in the vicinity of the upper edge of a coin path in accordance with the invention and the size I of the coils is varied.

A preferred embodiment of the invention will now be described in conjunction with the accompanying drawings.

Referring to Fig. 2, a coin path 10 is obliquely disposed at least in the vicinity of a place where a coin selection device 1 2 is provided so that an inserted coin will roll down along a lower side 1 Oa of the coin path 1 0. The coin selection device 1 2 is provided for discriminating the diameter of the coin. Another coin selection mechanism 11 is provided for discriminating material of the coin.

The coin selection mechanism 11 is one of a known type in which an oscillating coil and a receiving coil of about the same size as the height of the coin path 10 (i.e., the diameter of a coin of a maximum diameter passing through the coin path) are disposed on both sides of the coin path 10 and the oscillating coil is energized by a lower frequency (e.g. 10 kHz) suitable for discriminating the material of the coin.

The coin selection device 1 2 for discriminating the coin diameter according to the invention comprises an oscillating coil 1 2a and a receiving coil 1 2b mounted in the vicinity of an upper edge 1 Ob on both sides of the coin path 10 as shown in Fig. 3. The height I of the coils 1 2a and 1 2b is smaller than the height of the coin path 10. The coils 1 2a and 1 2b which are indicated in the figure as having a rectangular configuration are so wound that magnetic flux will cross in the direction of the width of the slit of the coin path 10.The height of the coils 1 2a and 1 2b should be sufficiently smaller than the height of the coin path 10 but must at least be large enough for the coin of the smallest diameter which rolls down along the lower side 1 Oa of the coin path 10 to enter the electromagnetic field range between the coils 1 2a and 1 2b at least partially. The height I of the coils 1 and 1 2b therefore is preferably set to be of a value equivalent to difference in the diameter between a coin A of the largest diameter and a coin B of the smallest diameter and the coils 1 2a and 1 2b should be disposed in the vicinity of the upper side 1 Ob at positions where the coils can react against at least a part of the coin B of the smallest diameter which rolls down along the lower side 1 Oa of the coin path 10.The oscillating coil 1 2a should preferably be excited by a high frequency (e.g. 100 kHz) suitable for discriminating the coin diameter.

According to the present invention, a degree to which mass of metal of a coin passing between the coils 1 2a and 1 2b occupies the electromagnetic field range between the coils 1 2a and 1 2b depends largely on difference in the coin diameter. More specifically, the range between the coils 12a and 1 2b is fully occupied by mass of metal when the coin A of the largest diameter passes through this range. The range is taken only slightly when the coin B of the smallest diameter passes. About half of the range is filled by mass of metal when a coin C of an intermediate diameter passes through the range. Consequently, the difference in the coin diameter appears as difference in the level of received signals in an enlarged scale whereby the discrimination of the coin diameter can be accurately effected.

Fig. 4 shows experimental data obtained by measuring levels of received signals when various values of the height I of the coils are adopted. In the experiment, the height I is varied in a range between 10 mm and 30 mm but in all cases the coils are disposed in the vicinity of the upper edge 1 Ob of the coin path 1 0. It will be noted that the coils assume about the same position as the prior art coin selection device 11 in a case where the height I is in the vicinity of 30 mm. In Fig. 4, curve I indicates results of measuring the level of the received signal with respect to a coin (metal piece) having diameter of 25 mm whereas curve II indicates those with respect to a coin having a diameter of 24 mm. It will be noted from Fig. 4 that the difference in the coin diameter represented by the level of the received signal increases as the height I of the coils decreases.

Claims

1. A coin selection device comprising a signal oscillating coil and a signal receiving coil disposed on opposite sides of a coin path to detect a coin passing through said coin path, in which said coin path has one side along which coins are moved while rolling, said signal oscillating coil and signal receiving coil are disposed towards the top end of a coin, i.e. towards a side opposite to said one side, and the size of said signal oscillating coil and signal receiving coil in a direction perpendicular to a coin rolling and moving direction is such that the upper end portion of a coin smallest in size passes slightly through the high electromagnetic field region of said signal oscillating coil and a coin largest in size passes wholly through the electromagnetic field region.

2. A machine as claimed in claim 1, in which said one side of said coin path is sloped and said coils are displaced towards the upper side of said passage way.

3. A machine as claimed in claim 1, in which the size of said coils is substantially equal to a difference in diameter between a coin largest in size and a coin smallest in size.

4. A coin selection device constructed, arranged and adapted to operate substantially as heretofore described with reference to, and as shown in, the accompanying drawings.