Source: {"pile_set_name": "USPTO Backgrounds"}

Coin dispensers used as coin returners in recreational machines, vending machines, etc. are already known.
In the current state of the art the following documents can be mentioned as background.
The document EP 1020818 describes a coin return mechanism based on a rotary disk in which the coins are transported to the outlet, once they are measured. Close to the outlet there exists a deflector so that in the event that the coin extraction is not desired, the coin is sent back to the inside of the device. This system has the inconvenience that it does not allow vertical growth in order to increase coin capacity. In some applications the capacity is increased by supplementary containers, but they have the inconvenience of their high volume compared to the obtained capacity. Another problem of this type of devices is that the coins are not extracted, they come back to the interior in a position close to the coin collection point, which is inconvenient since the coins which have not been extracted, since they do not correspond to the appropriate value, are better recycled as far away from coin collection by the extractor mechanisms as possible, thus enabling the arrival of different coins and therefore an appropriate coin recycling. By contrast, in the event the coins are rejected, the coins that have been rejected may be collected and rejected again.
The document WO 9813792 describes a coin roll or coin packet conveyor through a chain, to which buckets have been added to enable said transport. This mechanism is not fit for individual coin transport, nor is the function to discriminate between different types of coins described.
In the mechanism of WO 2006003212 a chain is used for coin extraction, said chain having links which are perpendicular to the plane defined by said chain. The coins are transported individually on the inner face of each one of the links and rest on a sloping ramp engraved on each link. The gears to allow the chain traction are located on the outer edge of the links. This mechanism has the inconveniences that the coin is extracted under the maximum elevation of the mechanism and at the outlet in a vertical plane a wide outlet mouth is needed, which complicates the corresponding coin guides. On the other hand, lateral transmission considerably increases the friction of the chain with the guides, resulting in a life reduction for the device and greater power of the track motor.
The document U.S. Pat. No. 3,910,295 refers to a coin vending machine where a chain is used for its transport, in the links of which there are alternating longer axes which serve as support for the chains. Therefore, the coins fit perpendicularly into the chain between two axes and rest on the sides of a vertical guide, in which the chain is centered. This system has the inconveniences that it allows a small range of coin sizes, upwardly limited by the width of the guide and downwardly limited by half said width. There also exists instability in the coin position which would make difficult its measuring before its extraction or recycling.
The document U.S. Pat. No. 3,703,903 refers to a coin vending machine consisting of a rigid cylinder having coin housings in the outer border. This system has problems to work with coins having an important range of diameters or thicknesses. It does not allow vertical growth without increasing the other dimensions, which is not useful when a considerably capacity and low volume are needed.
Finally, the document EP 1283505 B1 describes a conventional coin returning device, of the disk type, in which a supplementary storage unit is used to increase its capacity. The storage unit has a chain transport system similar to the previously described one in WO 2006003212. This system has the inconveniences of needing an important volume together with a considerable increase in the complexity of the mechanisms.