JPH05296917A - Frictional force measuring instrument - Google Patents

Abstract

PURPOSE:To prevent the tilting of paper so as to improve the measurement accuracy of the coefficient of friction of a roller to be measured and driving force acting on the paper by providing a second roller and supporting the paper by means of the second roller and the roller to be measured. CONSTITUTION:After sticking paper 20 to a holding plate 23, the plate 23 is put on a roller 21 and second roller 22 and a weight 24 is put on the plate 23. One end of the plate 23 is connected to a load cell 26 through a connecting section 25 and an electric current is made to flow to a motor 27. As the current increases, the torque measured by a torque meter 28 and tensile force measured by the load cell 26 increase. The roller 21 starts to rotate against the paper 20 at a certain point and an encoder 29 senses the point. The coefficient of static friction can be calculated from the torque measured by the meter 28 or the tensile force measured by the load cell 26 at the point and the weight of the weight 24. Therefore, accurate measurement can be performed, since the paper 20 is supported at two points by the rollers 21 and 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frictional force measuring device. As a paper feed mechanism for a CD (Automatic Payment Machine) or the like, a paper feed mechanism as shown in FIG. 4 is used.
The bills 3 are stacked on a rubber pick roller 1 and a feed roller 2, and the pick roller 1 is rotated so that the bills at the bottom are sequentially sent out through a separator 5 of a separating unit 4.

In such a mechanism, the frictional force between the paper and the rubber roller is a major factor in stabilizing the operation. However, the friction coefficient between the rubber roller, which is a viscoelastic body, and the plane is different from that of simple planes. Therefore, it is necessary to measure the shape close to the actual shape and obtain the friction coefficient.

[0003]

2. Description of the Related Art Therefore, a frictional force measuring device as shown in FIG. 5 has been developed. This is performed by placing the paper 7 and the paper retainer 8 and the weight 9 on the roller (pick roller) 6 for feeding out and fixing the movement in the lateral direction (direction of arrow A), and then applying torque to the roller 6 The coefficient of friction is measured by slippage. The roller 6 is rotated by the motor 10, but by controlling the current value of the motor,
The applied force can be gradually increased. The torque applied to the roller 6 is measured by the torque meter 12 attached to the shaft 11, and the tensile force applied to the paper 7 is measured by the load cell 13. The rotation of the roller 6 is measured by the encoder 14,
The movement of the paper 7 is measured by a laser displacement meter (not shown).

[0004]

In the above conventional frictional force measuring device, the paper 7 is supported only by the pick roller 6 as shown in FIG. 6 (a). Further, although the lateral movement is restricted by the connecting portion 15, there is a vertical degree of freedom. Therefore, when the torque of the roller 6 is increased by the measurement and a rotational force is applied, the paper 7 is inclined on the roller 6 as shown in FIG. 6B, and the accuracy of the measurement is lost.

The present invention seeks to realize a frictional force measuring device capable of measuring an accurate frictional force between a paper and a roller.

[0006]

In the frictional force measuring device of the present invention, a roller 21 that contacts the paper 20, a means for applying a load to the paper 20, and a means for fixing the progress of the paper 20.
In the frictional force measuring device provided with at least one of the means for measuring the tensile force applied to the paper 20 and the means for measuring the torque of the roller 21, a second roller 22 for supporting the paper 20 is provided in addition to the roller 21. It is characterized by

In addition to the above, the frictional force measuring device is provided with means for measuring the displacement of the paper 20. Further, in addition to the above, the frictional force measuring device is provided with means for measuring the angular displacement of the roller 21. By adopting this configuration, it is possible to obtain a frictional force measuring device capable of accurately measuring the frictional force between the paper and the roller.

[0008]

In the actual paper feeding mechanism, the paper is supported not only by the pick roller but also by the feeding roller called the feed roller. Therefore, in the frictional force measuring device of the present invention, the second roller 22 corresponding to the feed roller is attached, and the paper 20 is supported by both the second roller 22 and the roller 21 for measuring the frictional force. The inclination of the paper can be prevented. This makes it possible to measure the friction coefficient and the driving force acting on the paper in a form close to that of an actual paper feeding mechanism.

[0009]

FIG. 1 is a diagram showing an embodiment of the present invention,
(A) is a front view, (b) is sectional drawing in the bb line of (a) figure. In this embodiment, as shown in FIG.
A roller 21 that contacts the paper 20, a second roller 22 that supports the paper 20 together with the roller 21, a weight 24 that applies a load to the paper 20 via the holding plate 23, and a tensile force applied to the paper 7 can be measured. A load cell 26 connected to the holding plate 23 via a connecting portion 25, and a motor 27 for driving the roller 21.
And a torque meter 28 inserted between the roller 21 and the motor 27 so that the torque applied to the roller 21 can be measured.
And an encoder 29 for measuring the angular displacement of the roller 21.
And a laser displacement meter (not shown) for measuring the displacement of the paper 7, for example.

The operation of this embodiment thus constructed will be described below. First, the paper 20 to be measured is attached to the holding plate 23, placed on the roller 21 and the second roller 22, and the weight 24 is placed on the holding plate 23. In this case, the centers of the paper 7 and the pressing plate 8 and the center of gravity of the weight 24 need to be located on a vertical line passing through the center of the roller 21.

Further, one end of the pressing plate 23 is connected to the load cell 26 via the connecting portion 25. Then, a current is passed through the motor 27, and the current is gradually increased. As the current increases, the torque measured by the torque meter 28 and the tensile force measured by the load cell 26 increase, and at a certain point, the roller 21 starts to wander on the paper 20. This point can be known by the encoder 29. Then, the static friction coefficient can be calculated from the torque of the torque meter 28 at this point or the tensile force measured by the load cell 26 and the weight of the weight 24. Further, if the current applied to the motor 27 is increased, the dynamic friction can be measured.

In this case, since the paper 20 is supported by the roller 21 and the second roller 22 at two points and does not tilt as in the conventional case, accurate measurement can be performed.

2 and 3 are views showing data measured by the present embodiment and the conventional example. FIG. 2 shows the present embodiment, FIG. 3 shows the conventional example, and FIG. The relationship between the elapsed time from the current application and the rotation angle of the roller is shown, and (b) shows the relationship between the elapsed time from the current application to the motor and the force acting on the paper converted from the reading of the load cell. In the present embodiment shown in FIG. 2, the force acting on the paper at the time when the roller starts to slide is about 0.4 kg, whereas in the conventional example shown in FIG. The acting force is about 0.45 kg, which is larger than that in this embodiment. This is because, in the conventional example, the paper is inclined on the roller, and the tensile force is increased.

Although the time when the roller starts to wander is determined from the rotation angle of the encoder in FIGS. 2 and 3, it is necessary to accurately subtract the displacement of the paper 20. Therefore, when more accurate data is required, it is necessary to measure the displacement of the paper with a laser displacement meter.

[0015]

According to the present invention, the second roller for supporting the paper is provided in addition to the roller corresponding to the pick roller, so that the paper is prevented from being tilted due to the rotation of the roller and an accurate friction force is obtained. Can be measured, which can contribute to improvement in measurement accuracy of the frictional force measuring device.

[Brief description of drawings]

FIG. 1 is a view showing an embodiment of the present invention, in which (a) is a front view,
(B) is sectional drawing in the bb line of (a) figure.

FIG. 2 is a diagram showing measurement data according to an embodiment of the present invention,
(A) shows the relationship between the elapsed time from the current application to the motor and the rotation angle of the roller, and (b) shows the elapsed time from the current application to the motor and the force acting on the paper converted from the reading of the load cell. It is a figure which shows a relationship.

FIG. 3 is a diagram showing measurement data obtained by a conventional frictional force measuring device, in which (a) shows the relationship between the elapsed time from the current application to the motor and the rotation angle of the roller, and (b) shows the relation from the current application to the motor. It is a figure which shows the relationship between the elapsed time and the force acting on the paper converted from the reading of a load cell.

FIG. 4 is a diagram showing a conventional paper feeding mechanism.

5A and 5B are views showing a conventional frictional force measuring device, wherein FIG. 5A is a front view and FIG. 5B is a sectional view taken along line bb in FIG. 5A.

FIG. 6 is a diagram for explaining a problem to be solved by the invention.

[Explanation of symbols]

 20 ... paper 21 ... roller 22 ... second roller 23 ... holding plate 24 ... weight 25 ... connection part 26 ... load cell 27 ... motor 28 ... torque meter 29 ... encoder

Claims (3)

[Claims] 1. A roller (21) contacting a paper (20).
At least a means for applying a load to the paper (20), a means for fixing the progress of the paper (20), a means for measuring the tensile force applied to the paper (20) or a means for measuring the torque of the roller (21). A frictional force measuring device provided with one, characterized in that, in addition to the roller (21), a second roller (22) for supporting a paper (20) is provided. 2. The friction measuring device according to claim 1, wherein the paper (2
A frictional force measuring device provided with means for measuring the displacement of 0). 3. The frictional force measuring device according to claim 1, further comprising means for measuring an angular displacement of the roller (21).