JPH05147773A - Sheet double feed sensing device - Google Patents

Abstract

PURPOSE:To sense double feed of sheets simply and certainly by putting a sheet material to be transported with the middle part of a movable member, lifting thereby the leading edge round the base end of the movable member as fulcrum, and varying the lift amount of the leading edge in accordance with the thickness of the sheet material. CONSTITUTION:When a frame 9 as a sheet material is transported in the arrow direction 10 to come in contact with a bearing 14 for an arm 11 as a movable member, a force to press the bearing 14 up acts on the contacting point 13 of the arm 11. Thereby the arm 11 is heaved in the arrow direction 50 round a fulcrum 12, and the sensing point 15 is positioned at a level P1. Therein the distance from fulcrum 12 of the arm 11 to the sensing point 15 is set longer than the distance from the fulcrum 12 to the contacting point 13, so that in the event of double feed of frames 9, the sensing point 15 of the arm 11 is heaved still higher to be positioned at the height P2. That is, the amount 55 of level change of the frame 9 is amplified to the stroke difference 65 at the sensing point 15. This enables sensing a double feed simply and certainly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double feed detecting apparatus for sheet materials, and more particularly to a structure for easily and accurately detecting double feed of sheet materials.

[0002]

2. Description of the Related Art Generally, sheet materials are used for various purposes. As an example of its application, it may be used in an IC manufacturing process. In the IC manufacturing process, a sheet-shaped frame is used as a base on which an IC chip is mounted. The frames are automatically sucked by a suction mechanism or the like and placed one by one on the IC manufacturing process line. The mounted frame is conveyed on the line, and goes to the subsequent steps such as the mounting of the mounted IC chip, the fixing step and the cutting step.

However, when the frames are placed on the line, the frames may be placed in a stacked state.
If such double feeding of the frame occurs, it interferes with the subsequent steps. Therefore, double feed was detected and eliminated by using the following means. An example will be described with reference to FIG. A shutter 8 is located on the mounting surface 2,
The shutter space 5 between the two is adjusted to a height that allows only one frame 6 to pass through. Further, a feed claw 4 is provided inside the mounting surface 2 to press and convey the frame in the direction of arrow 90. If the frame 7 overlaps with the frame 6 and double feed occurs, the frame 7 is shut off by the shutter 8.
And the frame 6 only passes through. That is, only one frame is always passed and conveyed on the mounting surface 2 for the subsequent steps.

Another conventional example is to directly detect the thickness of the frame. For example, it provides a photoelectric sensor on top of the frame to measure the height of the frame. When the double feed of the frame occurs, the height of the frame changes, so that the double feed can be discriminated.

[0005]

However, the conventional double feed detection has the following problems. In double feed detection using a shutter, the frame 7 overlapped by the shutter 8 is blocked and only one frame 6 passes. Here, even when the frame 7 comes into contact with the shutter 8, the feed claw 4 allows the frame 6 to pass therethrough, so that the frame continues to be pressed in the direction of the arrow 90. Therefore, the frame 7 blocked by the shutter 8 is sandwiched between the feed claw 4 and bent. The frame 7 damaged in this way cannot be used in the IC manufacturing process, resulting in poor production efficiency.

On the other hand, in the conventional example in which the thickness of the frame is directly detected by using a photoelectric sensor or the like, there is no fear of the frame being damaged as described above. However, there are the following problems.
Normally, the thickness of the frame is very small, and the amount of change in height between the case of one sheet and the case of stacking two sheets is small. In order to detect such a small amount of change, a high-performance detector is required, which causes a problem of high production cost. If an inexpensive detector with poor performance is used, double feeding of the frame cannot be accurately detected.

In view of the above, the present invention aims to provide a sheet material double feed detecting device which does not damage the sheet material and which can reliably detect the double feed of the sheet material by an inexpensive detector. And

[0008]

SUMMARY OF THE INVENTION A sheet material double feed detecting apparatus according to the present invention comprises a conveying mechanism for conveying a sheet material in a predetermined direction, a fulcrum for supporting its rotation, and a conveying mechanism for conveying the sheet material. A movable member having a contact point that comes into contact with the sheet material and a predetermined detection point, and the distance from the fulcrum to the detection point is longer than the distance from the fulcrum to the fulcrum to the contact point. It is characterized by including a detector for detecting the amount of movement of the point.

[0009]

In the sheet material double feed detecting apparatus according to the present invention, the sheet material conveyed in the predetermined direction comes into contact with the contact point of the movable member. Then, the movable member moves around the fulcrum, and the detector detects the amount of movement at the detection point. At this time, the distance from the fulcrum to the detection point is set longer than the distance from the fulcrum of the movable member to the contact point.

Therefore, the movement of the movable member due to the passage of the sheet material is larger at the detection point than at the contact point. Further, the sheet material conveying operation can be stopped based on the detection of the detector. Therefore, the sheet material will not be bent due to the double feed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described by way of example when it is used in an IC manufacturing process.

FIG. 2 shows the external appearance of the sheet material double feed detecting device. The mounting table 1 is provided with a feed claw 4 as a transport mechanism. The feed claw 4 moves along the transport groove 6 and presses and transports the frame 9 in the direction of arrow 10. Also, the mounting table 1
A mounting wall 21 is provided on the mounting wall 21, and the arm 11 as a movable member is supported and mounted on the mounting wall 21 at a fulcrum 12. A bearing 14 is provided on the arm 11 and a detection point 15 is further formed. A detector 16 is fixed to the upper part of the arm 11 toward the detection point 15.

FIG. 3 is a plan view of the vicinity of the sheet material double feed detecting device. The frame stock section 19 stores a large number of frames to be worked. From the top of this stored frame, it is automatically adsorbed in sequence,
The sheets are placed on the placing table 1 one by one. The placed frame 9 is conveyed in the direction of arrow 10 by the feed claw 4. The paste in the paste unit 41 is applied to the conveyed frame 9, and the IC chip is mounted and adhered thereto.
Thus, thereafter, the IC product is manufactured through a predetermined process.

However, when the frame 9 is mounted on the mounting table 1 from the frame stock portion 19, the frame may be attached and double feed may occur. If such double feed occurs, it will seriously hinder the subsequent steps. Therefore, the double feed is detected by using the arm 11, the detector 16 and the like.

FIG. 1 is an enlarged side view of the detection mechanism. Normally, only one frame 9 is conveyed to the mounting table 2 in the direction of arrow 10. Then, the frame 9 contacts the bearing 14 provided on the arm 11. At this contact point 13, a force that presses the bearing 14 upward acts. As a result, the arm 11 moves around the fulcrum 12 with the arrow 50.
Pushed up in the direction. At this time, the detection point 15 of the arm 11
Is located at a height P1 shown in FIG. At this time, the bearing 14 is rotated by the movement of the frame 9. The rotation of the bearing 14 reduces friction caused by contact with the frame 9 and smoothes the transportation. In this embodiment,
Although bearings are used, other mechanisms may be used.

Next, two frames 9 are overlapped with each other, and an arrow 10
The movement of the arm 11 when it is conveyed in the direction and double feed occurs will be described.

The double frame 9 also contacts the bearing 14 and pushes up the arm 11 in the direction of arrow 50 in the same manner as described above. Here, the distance from the fulcrum 12 to the detection point 15 is
It is provided longer than the distance from the fulcrum 12 to the contact point 13. Therefore, the detection point 15 of the arm 11 is pushed up higher and is located at the height P2 shown in FIG. That is, the frame height change amount 55 based on the double feed is amplified to the stroke difference 65 in the detection 15. Therefore, by detecting this stroke difference 65, it is possible to reliably detect double feed without using a highly accurate detector. As the detector 16, for example, a reflective photoelectric sensor or the like may be used.

The double feed of the frame 9 is detected as described above. The double feed frame 9 detected next is detected.
The discharging operation of No. 2 will be described with reference to FIG. Note that FIG. 4A shows 1
FIG. 4B shows a normal operation of the feed claw 4 that conveys a single frame 9, and FIG. 4B shows an operation of discharging the double-feed frame 9.

When double feed is detected, the double feed frame 9 is discharged. When double feed is detected, the feed claw 4 first stops the conveyance of the frame 9 (FIG. 3). At this time, the tip of the frame 9 is located on, for example, the stop line 17 on the mounting table 1 (see FIG. 3). After that, the feed claw 4 once descends in the direction of the arrow 20 and sinks under the mounting table 1.
Then, it moves under the mounting table 1 in the direction of the arrow 10 and stops at the end 18 (FIG. 3) of the transport groove 6. Next, the feed claw 4 rises in the direction of the arrow 30 and again projects onto the mounting table 1 (FIGS. 3 and 4B). That is, the feed claw 4 moves under the mounting table 1 and wraps around the tip side of the frame 9. Thereafter, the feed claw 4 moves in the direction of arrow 40 while pressurizing the double-fed frame 9 (FIG. 4B). The double frame 9 sent by the feed claw 4 in the direction of the arrow 40 is stored in the double frame storage box 31 (FIG. 3).

In this way, the feed claws 4 perform the work of discharging the frame based on the detection of the detector 16, so that the process can proceed without interrupting the work and the production efficiency is improved.
Further, unlike the conventional double feed detection, the frame is not damaged and the frame can be reused.
It should be noted that the feed claw 4 immediately returns to the position before the frame is conveyed when the discharging work is completed. Therefore, the feed pawl 4 can perform a new frame transfer operation immediately after the double frame discharge operation is completed.

[0021]

In the double feed detecting device for a sheet material according to the present invention, the movement of the movable member due to the passage of the sheet material is larger at the detection point than at the contact point. Further, the sheet material conveying operation can be stopped based on the detection of the detector. Therefore, for example, the sheet material is not curved due to the double feed.

Therefore, it is possible to use an inexpensive detector instead of a high-performance detector, and it is possible to reliably detect the double feeding of the sheet material. Further, even if the sheet material is double-fed, it can be detected without damaging the sheet material.

[Brief description of drawings]

FIG. 1 is an enlarged side view of a detection mechanism of a sheet material double feed detector according to an embodiment of the present invention.

FIG. 2 is a perspective view showing the outer appearance of the sheet material double feed detection device shown in FIG.

FIG. 3 is a plan view of the vicinity of the sheet material double feed detection device shown in FIG.

FIG. 4 is a front view showing the operation of the feed claw shown in FIG.

FIG. 5 is a side view of a conventional sheet material double feed detection device.

[Explanation of symbols]

 9-frame 11-arm 12-fulcrum 13-contact point 14-bearing 15-detection point 16- Detector

Claims (1)

[Claims] 1. A movable mechanism having a conveying mechanism for conveying a sheet material in a predetermined direction, a fulcrum for supporting its rotation, a contact point for contacting the sheet material conveyed by the conveying mechanism, and a predetermined detection point. A sheet comprising a movable member having a fulcrum-to-detection point longer than a distance from the fulcrum-to-contact point, and a detector for detecting a movement amount of the detection point. Material double feed detector.