GB2354464A

GB2354464A - Defect marking apparatus.

Info

Publication number: GB2354464A
Application number: GB9928452A
Authority: GB
Inventors: Taiichiro Morishita
Original assignee: Takao Kinzoku Kogyo Co Ltd
Current assignee: Takao Kinzoku Kogyo Co Ltd
Priority date: 1999-09-24
Filing date: 1999-12-01
Publication date: 2001-03-28
Also published as: JP2001087687A; CA2290173A1; JP3385241B2; GB9928452D0

Abstract

Apparatus for marking defects on a workpiece 8 comprises a sensor 3, transfer means 2, a powder spray nozzle 4 and powder supplying means 6. The sensor may be moved in a predetermined path by a robot arm over the workpiece to sense for defects. Defects detected by the sensor are marked by spraying with powder preferably after the sensor has been rotated out of the way to avoid powder being deposited on the sensor. The powder supplying means 6 is operable to supply powder from a powder storage container 5 to the nozzle by means of compressed air 13. A control means 10 may be provided to operate a solenoid valve 16 in the powder supplying means when a defect is detected.

Description

2354464

TITLE OF THE INVENTION

DEFECTIVE POINT INDICATING APPARATUS BACKGROUND AND SUMMARY OF THE INVENTION

This invention relates to a defective point indicating apparatus which examines a work and marks defective points.

In an assembly process of many pressed parts with spot welding, for example, lack of parts on welded points may occur. Conventionally, such defective points are detected by a sensor, and painted with I iquid paint to mark tempo ra r i I y.

However, there is a problem of bad working circumstances caused by that working site and peripheral equipment are contaminated by the liquid paint which drops when the mark is painted, and air is polluted by organic solvent. And, dried liquid paint tends to clot in a spray nozzle and pipings, construction of painting apparatus is complicated and difficult to maintain, and removal of the liquid paint after the marking causes much labor.

It is therefore an object of the present invention to provide a defective point indicating apparatus with which the construction of the apparatus is simplified, working efficiency is improved, and working circumstances can be ameliorated.

BIR I EF DESCR I PT I ON OF THE DRAW I NGS The present invention will be described with reference to the accompanying drawings, in which:

Figure 1 is an explanatory view of construction showing a preferred embodiment of the present invention; Figure 2 is a cross-sectional view of a principal portion showing a powder supplying means; Figure 3 is a cross-sectional view showing a detached state of a case main body of a powder storing portion from a I id body; Figure 4 is an explanatory view showing an attachment angle of a sensor and a spray nozzle to a transfer means; Figure 5 is an explanatory view showing an inspection state; Figure 6 is an explanatory view showing a marking state; and Figure 7 is a cross-sectional view of a principal portion showing a state that powder in the powder storing portion is blown off by air.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invent ion wi I I now be described with reference to the accompanying drawings.

Figure 1 shows a preferred embodiment of a defective point indicating apparatus of the present invention. This defective point indicating apparatus provided with a transfer means 2 having a movable portion 1, a sensor 3 and a spray nozzle 4 attached to the movable portion 1 of the transfer means 2, and a powder supplying means 6 which supplies powder 5 to the spray nozzle 4 with air, is constructed as to mark a defective point of a work 8 with spraying the powder 5. And, 7 is an examination stage disposed near the transfer means 2 for holding the work 8.

To describe concretely, as shown in Figure 1 and Figure 4, the transfer means 2 is a robot arm in the preferred embodiment, and the arm has an attachment portion 9 oscillatable around a horizontal axis P at an end of the movable portion 1 (arm portion) which moves threedimensionally. And, the sensor 3 and the spray nozzle 4 are attached to the attachment portion 9 outward in radial direction with a predetermined central angle 8 of which center is the horizontal axis P.

An optical sensor, for example, is used as the sensor 3, which is electrically connected to a discrimination means 10 to output detecting signals. And, the discrimination means 10, electrically connected to the transfer means 2 and the powder supplying means 6 for controlling them, is described later in detail.

And, the spray nozzle 4 is fixed to the attachment portion 9 through a fixed pipe 11 forming a part of a powder supplying piping 35 with the angle 6 to the sensor 3, and connected to a powder storing portion 12 of the powder supplying portion 6 through the powder supplying piping 35. Further, a check valve 36 is disposed at a position near the spray nozzle 4 of the powder supplying piping 35 (namely, the fixed pipe 11).

As shown in Figure 1 and Figure 2, the powder supplying means 6 is provided with an air supplying portion 13, a moisture removing portion 14, a pressure regulating valve 15, an electromagnetic valve 16, and the powder storing portion 12, all of which are communicatively connected serially with an air piping 1T. Further, the electromagnetic valve 16, a two-position switching valve having two ports, is electrically connected to the discrimination means 10 as to be switched on and off (opened and, closed).

And, as shown in Figure 2 and Figure 3, the powder storing portion 12 has a case main body 18 opening upward to contain the powder 5, and a I id body 19 detachably attached to an upward opening portion of the case main body 18. In the case main body 18, a female screw portion 20 is formed on an opening end, and a short cylindrical portion 21 and a circular protruding portion 22 are concentrically formed on a center of an inside bottom portion. And, the lid body 19 has a lid portion 23 of flat plate and a cylindrical portion 24 vertically protruding downward from a lower face of the I id portion 23. And, a male screw portion 25 which screws into the female screw portion 20 is formed on a peripheral face of the cylindrical portion 24.

And, a thick wal I portion 28 is formed on an upper face of the I id portion 23 in wh ich a suct ion hole 26 and a discharge hole 27 of horizontal direction are formed. The suction hole 26 is communicatively connected to the electromagnetic valve 16 through the ai r piping 17, and the discharge hole 27 is communicatively connected to the spray nozzle 4 through the powder supplying piping 35. And, an attachment cyl inder portion 29 communicating with the suction hole 26 is formed on the lower face of the I id portion 23, and an upper end of a pipe body 30 is attached to the attachment cylinder portion 29.

The pipe body 30 has an attachment port ion 31 of short cyl inder f itted to the attachment cylinder portion 29, a main body portion 32 having a male screw portion on an upper end which screws into a female screw portion formed on a lower part of the attachment portion 31. In a state that the I i d body 19 i s attached to the case ma i n body 18, the ma i n body po rt i on 32 of the p i pe body 30 bends outwa rd i n the rad i a I direction as to avoid the cylindrical portion 21 and the circular protruding portion 22 of the case main body 18, and a lower end of the pipe body 30 is open and curved as to hold the protruding portion 22 in a peripheral direction.

In the powder storing portion 12 constructed as described above, for example, the lid body 19 is suspendedly held with an approximately Zshaped holding member 34 standing on an upper face 33 of a fixation member such as a bench on which the powder supplying means 6 is placed.

- 6 Therefore, the powder 5 is easily refilled in the case main body 18 detached from the lid body 19.

Next, working and effects of the defective point indicating apparatus of the present invention are described. Figure 1 shows an examinat ionwaiting state in which the electromagnetic valve 16 of the powder supplying means 6 is closed. And, for example, in a case whether a part A of the work 8 exists or not (lack of the part A) is examined, the sensor 3, moved toward an examined point (the part A) by driving the movable portion 1 of the transfer means 2, checks the lack of the part A. That is to say, when the part A exists, non-defection detecting signal is sent by the sensor 3 to the discrimination means 10, and the discrimination means 10 keeps the electromagnetic valve 16 closed thereby.

However, as shown inFigure 5, when thepart A is not on the exam i ned po i nt, de f ect i on detec t i ng s i gna I i s sent by t he senso r 3, d i rected to the exam i ned po i nt, to the d i sc r i m i nat i on means 10, and, the attachment po rt i on 9 of the movab I e por t i on I of the t ransf e r po r t i on 2 is oscillated for the predetermined central angleO to direct the spray nozzle 4 to the defective point (the examined point) according to an output signal f rom the discrimination means 10 as shown in Figure 6. Then, the electromagnetic valve 16 of the powder supplying portion 6 is switched to an open state for a predetermined time by an output signal f rom the discrimination means 10, and compressed ai r is sent f rom the air supplying portion 13 to the powder storing portion 12 thereby.

Then, as shown in Figure 6 and Figure 7, the compressed ai r is blown out of a lower end opening of the pipe body 30 through the suction hole 26 of the lid body 19, the powder 5 on the bottom portion of the casemain body 18 is blown off, and the powder 5 mixed with the air is sent f rom the d i scha rge ho I e 27 of the I i d body 19 to the sp ray nozz I e 4 through the powder supplying piping 35 and discharged to the outside. That is to say, the powder 5 is sprayed onto the defective point of the work 8 to mark.

In this case, the sensor 3 is not contaminated by rebound of the discharged powder 5 for that the sensor 3 and the spray nozzle 4 are pa rted f o r the p redete rm i ned cent ra I ang I e 0, and p revented f rom reducing the abi I ity. And, the powder 5 does not drop f rom the spray nozzle 4 af ter the discharge for the check valve 36 arranged at a position near the spray nozzle 4 of the powder supplying piping 35. Unnecessary parts of the work 8 are not marked, and working site is not contaminated thereby. Further, the spray nozzle 4 is parted from and closed to the work 8 to enlarge and diminish area of the marking. And, as the powder 5, for example, powdered chalk, pigment, etc. of which color is preferably distinctive when marked on the work 8, are used.

As described above, the powder 5 is sprayed from the spray nozzle 4 to mark when the sensor 3 detects a defective point. In case that plural examined points exist, the sensor 3 approaches every point to confirm whether the point is defective or not. If the point is not defective, the sensor 3 is moved to next examined point. If the point is defective, the apparatus marks on the defective point and the sensor 3 is moved to next examined point.

And, in the present invention, not restricted to the embodiments above, for example, an open-close shielding lid may be attached to the position of the sensor 3 (an optical sensor) and the spray nozzle 4 may be disposed near the sensor 3 in the same direction of the sensor 3. And, a magnetic sensor (not influenced by the powder 5) may be used as the sensor 3 and the spray nozzle 4 may be disposed near the sensor 3 in the same direction of the sensor 3. The marking on the defective point can be conducted more swiftly thereby.

And, in the present invention, although a case that lack of parts is examined is shown, it is also possible to examine whether the work 8 has a hole or not (one of which is defined as defective). And, the transfer means 2, not restricted to a robot arm moves threedimensionally, may have a movable portion which moves one or twodimensionally.

According to the defective point indicating apparatus of the present invention, the apparatus has a simple construction and can be made by low production cost in comparison with a conventional marking apparatus with liquid paint for the construction in which the defective point of the work 8 is marked with the powder 5. And, the powder 5 causes much I ess t roub I es such as a c I ot than the I i qu i d pa i nt, and the apparatus is easily maintained. And, working circumstance becomes improved and easy to control because organic solvent is not used. Further, while liquid paint requires much labor for removal after the marking, the powder 5 is easily wiped off to be removed, and working efficiency is improved thereby.

And, the sensor 3 is not contaminated by rebound of the powder 5 sprayed from the spray nozzle 4 to the defective point of the work 8, and the sensor 3 (an opt i ca I sensor, for example) is prevented from reducing the abi I i ty wi th adhesion of the powder 5.

Fu rther, unnecessa ry po i nts of the work 8, wo rk i ng s i te, and peripheral equipment are not contaminated with the powder 5 because the powder 5 does not drop (after leak) from the tip of the spray nozzle 4 after the discharge of the powder 5. And, the working circumstances are improved further.

And, according to the defective point indicating apparatus, the powder 5 is certainly blown off by the air within a short period of time and discharged from the upper portion of the powder storing portion 12, and the powder 5 mixed with the air is sent to the spray nozzle 4 efficiently.

Further, in the powder storing portion 12, the powder 5 is easily refilled because the case main body 18 is detachable from the lid body 19 connected to the air piping 17 and the powder supplying piping 35. In - 1 0 - this case, the pipe body 30 is not an obstacle to filling the case main body 18 w i th the powde r 5 because the p i pe body 30 i s on the I i d body 19 side.

While preferred embodiments of the present invention have been described in this specification, it is to be understood that the embodiments are illustrative and not restrictive, because various changes are possible within the scope of the invention, as set out in the appended claims.

CLA I MS 1. A defective point indicating apparatus comprising a transfer means having a movable portion, a sensor attached to the movable portion of the transfer means for detecting a defective point of a work, a spray nozzle attached to the movable portion of the transfer means for spraying powder, and a powder supplying means which supplies the powder to the spray nozzle by air, wherein the powder is sprayed from the spray nozzle on the defective point of the work to mark.

2. The defective point indicating apparatus as set forth in claim 1, wherein the movable portion of the transfer means has an attachment portion oscillatable around an axis, the sensor and the spray nozzle are attached to the attachment portion outward in a radial direction with a predetermined central angle, and the attachment portion oscillates for the predetermined central angle to direct the spray nozzle to the defective point after detection of the defective point by the sensor directed to an examined portion of the work.

3. The defective point indicating apparatus as set forth in claim 1 or 2, wherein a check valve is arranged at a position in a powder supplying piping of the powder supplying means near the spray nozzle.

4. The defective point indicating apparatus as set forth in claim 1 or 2, wherein the powder supplying means is provided with an air supplying portion for supplying compressed air and a powder storing - 1 2 - Portion connected to the air supplying Portion and the spray nozzle for storing the Powder, the compressed air from the air supplying portion is blown out of a lower portion inside the powder storing portion to blow off the powder, and the powder mixed with the air is discharged from an upper portion of the powder storing portion and sent to the spray nozzle.

5. The defective point indicating apparatus as set forth in claim 4, wherein the powder storing portion is provided with a case main body opening upward for storing the powder, and a lid body, having a pipe body for sending the compressed air to a bottom portion of the case main body and a discharge hole for discharge of the powder mixed with the air, detachably attached to the case main body.

6. A defective point indicating apparatus substantially as herein described with reference to Figures I to 7 of the accompanying drawings.