JPS6142697B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a double-feed prevention device for paper sheets, and more particularly to an improvement of a double-feed prevention device called a friction retard.

As is well known, the most common and simple configuration of a friction retard double feed prevention device is shown in Fig. 1 or 2.
As shown in the figure, an eccentric or half-moon shaped paper delivery drum 1
The paper sheets are fed out one by one from the stack 3 of paper sheets, and passed between the sending drum 1 and a retard pad fixed opposite thereto, a fixed belt 2, or a roll-shaped friction body. The paper feeder is configured such that the frictional force on the surfaces of the feed drum 1, the pad or belt 2, and the three handled paper sheets is as follows: feed drum - paper sheets > paper sheets - pad > paper The material and surface condition of the delivery drum 1 and the pad or belt 2 are selected so as to produce leaf-paper leaves.

The above-mentioned configuration is extremely simple and inexpensive, yet reliably prevents double feeding, and has been widely used in paper handling devices. 2 wears out, so its function cannot be maintained over a long period of time.

Therefore, instead of the retard pad or belt, a retard roll 4 or belt as shown in FIG. 3 is connected to a suitable power source 14 via a one-way clutch 8.
Also widely used is a retard member that is connected to the feed drum 1 to apply a rotational force in the opposite direction to the feed drum 1 so that the same part of the retard member does not wear out.

However, the above-mentioned double feed prevention device has the disadvantage that it is mechanically complex and expensive, and there is no guarantee that the entire circumferential surface of the retard roll or belt will wear uniformly, so that partial wear often occurs.

The present invention has been made in order to eliminate the defects of the conventional friction retard type multi-feed prevention device as described above. By rotating the retard belt little by little by utilizing the recoil generated when the belt expands and contracts as it comes into contact with and separates from the retard belt, the frictional pressure contact point with the sheet delivery drum is moved, and the belt is evenly spread. The object of the present invention is to provide a double feeding prevention device that is designed to wear out.

The present invention will be explained in detail below with reference to drawings showing embodiments.

FIGS. 4 and 5 are diagrams showing the structure and operation of an embodiment of the double feeding prevention device of the present invention.

In this figure, an endless retard belt 2 is wound around rolls 5 and 6 facing the eccentric paper delivery drum 1, and the endless retard belt 2 is attached to the rolls 5 and 6 only in the direction of arrows 7 and 7, respectively. One-way clutches 8, 8 are provided to allow rotation.

Further, a sheet stacking table 9 is provided on the right side of the delivery drum 1, and a stopper 10 for preventing the sheet pile 3 on the table from collapsing and a back pressing device 11 for sheet sheet stacking are provided.

To explain the operation of the double feeding prevention device having such a configuration, first, the delivery drum 1 comes into contact with the paper stack 3 and directs the topmost paper towards the retard belt 2. and send it out. Next, the delivery drum 1 is brought into pressure contact with the belt 2, and while the belt 2 is bent, the paper material is delivered by friction between the two as if it were "squeezing".

At this time, the belt 2 is connected to the one-way clutch 8,
8, and when two or more paper sheets are interposed between the delivery drum 1 and the belt 2 at the same time or with some deviation, the belt 2 cannot be rotated as described above. Since the frictional force between the paper sheet and the paper sheet is much larger than that between the paper sheets, only the topmost sheet is fed out, thereby preventing double feeding.

On the other hand, when the belt 2 is bent by the delivery drum 1, tension is applied to the roll 5 in a direction in which it can rotate, while tension is applied in a direction in which the roll 6 cannot rotate.

Therefore, the belt 2 is stabilized in a state where it rotates slightly clockwise in the figure around the roll 5, and T and T are formed on the side of the belt 2 in contact with the delivery drum 1 and on the opposite side, respectively. ₂ tension is applied. It is clear that T ₁ =T ₂ here.

Next, when the pressure contact between the delivery drum 1 and the belt 2 is released, the energy stored in the belt 2 prevents the rolls 5 and 6 from rotating counterclockwise and clockwise, respectively. 5 cannot be rotated by the action of the one-way clutch 8, and only the roll 6 can be rotated clockwise.
In this way, the belt 2 rotates slightly clockwise each time it is brought into and out of pressure contact with the delivery drum, and the friction contact point between the two changes every moment.

Incidentally, if the release of the pressure contact between the delivery drum 1 and the belt 2 progresses too slowly, the release of the energy stored in the belt 2 will also be slow and cancel out various frictional forces. The movement may not proceed reliably.

Therefore, if the shape of the delivery drum 1 is such that it has a cutout 12 as shown in FIG. 6, and the ends of the cutout are connected with a curved line with a small curvature, the energy can be released quickly and reliably. The belt 2
It is effective in rotating the

Although the present invention has been described above only with respect to an embodiment using a retard belt, it is not necessarily limited to this, and instead of a belt, a retard roll 13 having sufficient elasticity and elastic deformation as shown in No. 7 is used. It is also possible to perform similar operations. However, if a roll that does not have a long circumference is used, it is inevitable that the lead member replacement interval will be shorter than when a belt is used.

Since the present invention is constructed as described above, it is possible to move the friction contact point between the paper delivery drum and the retard member from time to time without requiring a special power source or a connection mechanism to the power source, which is inexpensive. Since local friction of the retard member can be prevented and the replacement interval can be increased, this has a significant effect in terms of maintenance services for paper handling devices.

[Brief explanation of the drawing]

1 to 3 are diagrams showing the configuration of a conventional friction retard double feed prevention device, FIGS. 4 and 5 are diagrams explaining the configuration and operation of the double feed prevention device of the present invention, and FIG. 6 is a diagram showing the configuration of a conventional friction retard double feed prevention device. FIG. 7 is a diagram showing another embodiment of the paper sheet delivery drum used in the double feeding prevention device of the invention. Reference numeral 1 indicates a paper delivery drum, 2 a separation belt, 3 a paper stack, and 8 a one-way clutch.

Claims (1)

[Claims] 1. A device that continuously separates and sends paper sheets from a pile of paper sheets, which is equipped with an eccentric paper sheet delivery drum that rotates at a constant speed and a separation belt for preventing double feeding provided opposite to the delivery drum. Then, the separation belt is hooked around via a one-way clutch that can rotate only in the opposite direction to the rotational direction of the delivery drum, and the separation belt is rotated by utilizing the recoil caused by expansion and contraction of the belt caused by coming into contact with and separating from the delivery drum. An apparatus for preventing double feeding of paper sheets, characterized in that a friction contact point between the separation belt and the delivery drum is moved each time the delivery drum rotates.