Device and method for determining the quality of driver bits

Abstract

To provide a driver bit quality determination device and method that can determine the quality of the shape of a driver bit with great detail and high precision. [Solution] An inspection jig 2 is used, which is provided with multiple inspection holes 2a, 2b, 2c, and 2d corresponding to multiple axial locations on the drive transmission part 12a of the driver bit 12. The drive transmission part 12a of the driver bit 12 is sequentially fitted into each of the inspection holes 2a, 2b, 2c, and 2d of the inspection jig 2, and the amount of insertion is measured as the actual insertion amount. This actual insertion amount is compared with a reference insertion amount, which is the amount of insertion of a pre-set appropriate driver bit into each of the inspection holes 2a, 2b, 2c, and 2d, to determine whether the shape of the drive transmission part 12a of the driver bit 12 under inspection is good or bad. This makes it possible to individually determine the degree of wear on each axial part of the drive transmission part 12a of the driver bit 12 under inspection.

Description

Technical Field

[0001] The present invention relates to a quality determination device and a quality determination method for determining whether the shape of a drive transmission portion of a driver bit is good or bad.

Background Art

[0002] Screw tightening devices, screw tightening drivers and the like for tightening screws use driver bits provided with a drive transmission portion that can be engaged with the drive portion of a screw. As such a driver bit, for example, a so-called Phillips driver bit having a drive transmission portion shape conforming to Japanese Industrial Standards B4633 "Phillips Screwdrivers" is well known. Since the original function of such a driver bit is impaired by wear or chipping of the drive transmission portion due to use, the driver bit is appropriately replaced based on indicators such as the service period and the number of screw tightening operations. Also, as disclosed in Patent Document 1, a screw tightening device capable of detecting wear of a driver bit is known. This screw tightening device is configured to compare a taught absolute position when the driver bit is engaged with a teaching screw arranged at a predetermined position, and a measured absolute position when the driver bit is engaged with an actual tightening screw arranged at the same position, so that wear of the driver bit can be detected.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The degree of wear and tear on driver bits varies greatly from one unit to another. When using the aforementioned usage period and number of screw tightening cycles as a guide, there is a problem in that still usable driver bits are replaced and discarded. Furthermore, quality judgment methods such as the screw tightening device described in Patent Document 1 can only detect wear and tear that affects the degree of engagement with the screw's drive mechanism, such as wear and tear on the entire drive transmission part of the driver bit. This has resulted in problems such as the inability to detect changes in shape, such as wear or chipping in the middle of the cross-shaped portion of a Phillips driver bit, or other localized or unevenly distributed wear and tear. [Means for solving the problem]

[0005] This invention was created in view of the above-mentioned problems, and aims to provide a driver bit quality determination device and method that can determine the quality of the shape of a driver bit in a detailed and highly accurate manner.

[0006] To achieve the above objective, the present invention provides a quality determination device for detecting the quality of the shape of a drive transmission part of a driver bit, which has a tapered drive transmission part that can engage with the drive part of a screw, and is characterized by comprising an inspection jig provided with a plurality of inspection holes corresponding to a plurality of axial locations of the drive transmission part of the driver bit. With this configuration, by sequentially fitting the driver bit into the plurality of inspection holes, it is possible to detect changes in the shape of each axial part of the drive transmission part.

[0007] Furthermore, it is desirable to have a quality determination means that maintains the insertion amount when a proper driver bit is fitted into each inspection hole as a reference insertion amount, and compares the insertion amount when the driver bit to be inspected is sequentially fitted into each inspection hole with the reference insertion amount to determine the quality of the shape of the drive transmission part of the driver bit. This makes it possible to individually compare the degree of wear or damage of the used driver bit to be inspected with that of a proper, unworn driver bit whose reference insertion amount has been measured, for each axial part of the drive transmission part, and to determine the quality of the shape of the driver bit to be inspected based on the results.

[0008] To achieve the above objective, the present invention provides a method for determining the shape quality of a drive transmission part of a driver bit, which is equipped with a tapered drive transmission part that can engage with the drive part of a screw. The method involves preparing an inspection jig with a plurality of inspection holes corresponding to a plurality of axial locations of the drive transmission part of the driver bit, sequentially fitting the drive transmission part of the driver bit into each inspection hole of the inspection jig, measuring the amount of insertion as the actual insertion amount, comparing this actual insertion amount with a reference insertion amount which is a preset insertion amount of a proper driver bit into the inspection hole, and determining the shape quality of the drive transmission part of the driver bit measured by the actual insertion amount based on the comparison result. This method makes it possible to individually compare the degree of wear or damage to each axial part of the drive transmission part of a used driver bit to be inspected with a proper, unworn driver bit for which the reference insertion amount has been measured, and to determine the shape quality of the driver bit to be inspected according to the result. [Effects of the Invention]

[0009] According to the present invention, since the shape changes of each axial part of the drive transmission section of the driver bit can be detected individually, the quality of the shape of the driver bit can be determined with great detail and high accuracy. As a result, it is possible to accurately determine the replacement time of the driver bit during use over time, and there are advantages such as being able to reduce the waste of driver bits. In addition, it is possible to detect wear and damage that occur locally and unevenly on the driver bit. Furthermore, by providing a quality determination means, it is possible to perform quality determination of the driver bit automatically, and there are advantages such as being able to incorporate this quality determination device into an automatic screw tightening device and incorporate quality determination of the driver bit into the automatic screw tightening work process. [Brief explanation of the drawing]

[0010] [Figure 1] This is a block diagram illustrating an embodiment of a driver bit quality determination device according to the present invention. [Figure 2]This is an explanatory diagram of an inspection jig in a driver bit quality determination device according to the present invention. [Figure 3] This is an explanatory diagram of the operation of the driver bit quality determination device according to the present invention. [Figure 4] This is an explanatory diagram of the operation of the driver bit quality determination device according to the present invention. [Figure 5] This is an explanatory diagram of the operation of the driver bit quality determination device according to the present invention. [Modes for carrying out the invention]

[0011] The following describes an embodiment of the driver bit quality determination device according to the present invention. In Figure 1, 1 is the driver bit quality determination device (hereinafter simply referred to as the quality determination device), and consists of an inspection jig 2 and a determination processing unit 3. This quality determination device 1 is installed in combination with an automatic screw tightening device 10, which consists of a screw tightening tool 13 equipped with a driver bit 12 that can be rotated by the drive of a motor 11, a tool moving unit 14 such as a multi-joint robot that supports the screw tightening tool 13 so that it can be moved to a predetermined position, and a control unit 15 that controls the driving of the screw tightening tool 13 and the tool moving unit 14.

[0012] The driver bit 12 is a so-called Phillips head driver bit, having a drive transmission part 12a at its tip that has a cross-shaped cross-section and a tapered shape. The drive transmission part 12a is engaged with the drive part (Phillips head) of a screw with a Phillips head to transmit screw tightening torque.

[0013] The quality determination device 1 is configured to place an inspection jig 2 within the movement range of the screw tightening tool 13 of the automatic screw tightening device 10, and to inspect the driver bit 12 as needed. As shown in Figures 2 and 3, the inspection jig 2 is a rectangular plate with four inspection holes 2a, 2b, 2c, and 2d of different diameters formed through it. The diameters of these inspection holes 2a, 2b, 2c, and 2d correspond to the circumscribed circles of four points in the axial direction of the drive transmission part 12a of a proper driver bit 12mst that is free from wear and damage, and are configured to cause the amount of insertion of the driver bit 12mst to differ when the driver bit 12mst is fitted into each of the holes. Furthermore, these inspection holes 2a, 2b, 2c, and 2d are countersunk holes, and the shape of the countersunk holes is configured to follow the tapered shape of the drive transmission part 12a.

[0014] The judgment processing unit 3 comprises a calculation control unit 4 that acquires movement position information (coordinate information) of the driver bit 12 from the control unit 15 of the automatic screw tightening device 10, calculates the movement position of the driver bit 12, and determines whether the shape of the driver bit 12 is good or bad from there, a storage unit 5 that stores the calculation processing results of the calculation control unit 4, the good or bad judgment results, various setting values, etc., and a display unit 6 that displays the good or bad judgment results from the calculation control unit 4, etc.

[0015] The memory unit 5 stores the respective movement amounts h1, h2, h3, and h4 (hereinafter referred to as the reference entry amounts h1, h2, h3, and h4) for each inspection hole, from a predetermined position Rp above the inspection holes 2a, 2b, 2c, and 2d until the driver bit 12mst, free from wear and damage, is fitted into the inspection holes 2a, 2b, 2c, and 2d and stops. These reference entry amounts h1, h2, h3, and h4 are acquired in advance using the teaching function of the automatic screw tightening device 10. That is, the reference entry amounts h1, h2, h3, and h4 are acquired in advance for each inspection hole 2a, 2b, 2c, and 2d by performing the following steps (see Figure 3). (Step 1) The tool movement unit 14 of the automatic screw tightening device 10 is operated to position the driver bit 12mst at a predetermined position Rp vertically above the inspection hole (hereinafter referred to as the measurement reference position Rp), and the calculation control unit 4 acquires the coordinate information of this measurement reference position Rp through the control unit 15. (Step 2) The tool movement unit 14 is operated to lower the driver bit 12mst until it is fitted into the inspection hole and stops, and the calculation control unit 4 obtains the coordinate information of this fitted stop position through the control unit 15. (Step 3) The calculation control unit 4 calculates the amount of movement of the driver bit 12mst, i.e., the reference entry amount, from the acquired coordinate information of the measurement reference position Rp and the coordinate information of the mating stop position, and stores it in the storage unit 5.

[0016] Next, the operation of the quality determination device 1 according to the present invention will be explained. Each time the automatic screw tightening device 10 tightens a predetermined number of screws, the quality determination device 1 is used to determine the quality of the shape of the drive transmission part 12a of the driver bit 12, that is, whether the driver bit 12 needs to be replaced due to wear, damage, etc. of the drive transmission part 12a. This determination of the quality of the shape of the drive transmission part 12a of the driver bit 12 is performed in the following steps (see Figures 4 and 5). (Step 1) The tool movement unit 14 of the automatic screw tightening device 10 is operated to position the driver bit 12 at a measurement reference position Rp vertically above the inspection hole, and the calculation control unit 4 acquires the coordinate information of this measurement reference position Rp through the control unit 15. (Step 2) The tool movement unit 14 is operated to lower the driver bit 12 until it fits into the inspection hole 2a and stops, and the calculation control unit 4 obtains the coordinate information of this fitting stop position through the control unit 15. (Step 3) The calculation control unit 4 calculates and determines the amount of movement ha1 of the driver bit 12 (hereinafter referred to as the actual entry amount ha1) from the acquired coordinate information of the measurement reference position Rp and the coordinate information of the mating stop position. (Step 4) The arithmetic control unit 4 reads the reference entry amount h1 of the corresponding inspection hole 2a from the storage unit 5, compares this with the actual entry amount ha1 obtained in Step 3, and determines whether the difference is within a predetermined allowable range. The determination result of "OK" when within the allowable range and "NG" when outside the allowable range is stored in the storage unit 5. (Step 5) Steps 1 to 4 are also performed for each of the inspection holes 2b, 2c, and 2d to obtain the corresponding actual entry amounts ha2, ha3, and ha4, which are compared and determined with the corresponding reference entry amounts h2, h3, and h4. Then, the arithmetic control unit 6 displays and outputs the determination results for each of the inspection holes 2a, 2b, 2c, and 2d on the display unit 6.

[0017] In the pass / fail determination of the driver bit 12 through the above steps, the driver bit 12 is sequentially fitted into each of the inspection holes 2a, 2b, 2c, 2d. Since each of the inspection holes 2a, 2b, 2c, 2d has a diameter corresponding to the circumscribed circle at four points in the axial direction of the tapered drive transmission portion 12a of the driver bit 12, shape abnormalities due to wear or chipping can be individually detected at the four axial positions of the drive transmission portion 12a. Therefore, even if localized or uneven wear or chipping occurs in the drive transmission portion 12a, such as when the middle of the cross portion is worn or chipped, this can be detected. As a result, the pass / fail determination of the shape of the driver bit 12 can be performed in a detailed and highly accurate manner, and screw tightening work can always be performed using an appropriate driver bit.

[0018] Figures 4(a) and 4(b) show an inspection state in which the driver bit 12, whose drive transmission portion 12a is worn substantially uniformly along the axial direction, is fitted into each of the inspection holes 2a, 2b, 2c, 2d. When the drive transmission portion 12a of the driver bit 12 is worn substantially uniformly and becomes thinner, a difference occurs between the actual entry amounts ha1, ha2, ha3, ha4 and the reference entry amounts h1, h2, h3, h4 in any of the inspection holes. That is, the pass / fail determination results of all the inspection holes 2a, 2b, 2c, 2d are NG.

[0019] Figures 5(a) and 5(b) show an inspection state in which a driver bit 12 having a defect such as a dent or chipping in a part of the drive transmission portion 12a (the part corresponding only to the inspection hole 2a) is fitted into each of the inspection holes 2a, 2b, 2c, and 2d. When a defect occurs in a part of the drive transmission portion 12a of such a driver bit 12, the actual penetration amounts ha2, ha3, ha4 in the inspection holes 2b, 2c, 2d coincide with the reference penetration amounts h2, h3, h4. However, in the inspection hole 2a, the driver bit 12 is displaced or tilted to fit into the inspection hole 2a by the amount corresponding to the generated defect, so that a difference occurs between the actual penetration amount ha1 and the reference penetration amount h1. Since the pass / fail judgment result of the inspection hole 2a becomes NG due to this difference, it is also possible to detect partial breakage or wear of the driver bit 12.

[0020] Furthermore, the arithmetic control unit 4 displays and outputs the pass / fail judgment results for each of the inspection holes 2a, 2b, 2c, and 2d as a list on the display unit 6, so that the judgment index for replacement of the driver bit 12 can be visualized. This allows the operator to easily grasp which part of the driver bit 12 has an abnormality such as wear or defect, and facilitates the judgment of whether the driver bit 12 needs to be replaced.

[0021] Note that in the pass / fail judgment apparatus 1 described above, the inspection holes 2a, 2b, 2c, and 2d are formed to penetrate through the plate-shaped inspection jig 2, but the inspection holes 2a, 2b, 2c, and 2d may have a bottom as long as they can be fitted until the driver bit abuts and stops. Further, the shape of the inspection holes 2a, 2b, 2c, and 2d is not limited to a circular shape, and may be, for example, a cross shape corresponding to the cross-sectional shape of each portion of the drive transmission portion 12a in the axial direction.

[0022] Furthermore, while the above explanation describes an example of automatically determining the shape quality of the driver bit 12, this quality determination device 1 can also determine the shape quality of the driver bit 12 manually. In the case of manual determination, a length measuring sensor (not shown) capable of measuring the amount of protrusion of the tip of the driver bit 12 when the driver bit 12 is fitted into each inspection hole 2a, 2b, 2c, 2d is placed below the inspection jig 2. Then, as described above, the determination processing unit 3 acquires and stores in advance the amount of protrusion when a suitable driver bit 12 is fitted into each inspection hole 2a, 2b, 2c, 2d as a reference insertion amount. When checking the shape quality of the driver bit 12, the determination processing unit 3 determines the amount of protrusion when the driver bit 12 to be inspected is sequentially fitted into each inspection hole 2a, 2b, 2c, 2d, and compares this to the reference insertion amount as the actual insertion amount to determine whether it is good or bad. In this way, the shape quality of the driver bit 12 can also be determined manually. Therefore, even with screw-tightening tools that are held and handled by the operator, such as hand screwdrivers, it becomes possible to determine the quality of the shape of the driver bit 12 and always use the appropriate driver bit 12 for screw-tightening work.

[0023] Furthermore, the parts supply device according to the present invention is not limited to the above-described configuration, and various modifications are possible without departing from its spirit. [Explanation of Symbols]

[0024] 1. Quality determination device 2. Inspection fixture 2a, 2b, 2c, 2d Inspection holes 3. Determination Processing Unit 4. Calculation Control Unit 5 Storage section 6 Display section 10 Automatic screw tightening device 11 Motor 12 driver bits 12mst appropriate driver bit 12a Drive transmission section 13 Screw tightening tools 14 Tool Transfer Units 15 Control Unit

Claims

1. A quality determination device for detecting the quality of the shape of a drive transmission part of a driver bit, which is equipped with a tapered drive transmission part that can engage with the drive part of a screw, A device for determining the quality of a driver bit, characterized by comprising an inspection jig having a plurality of inspection holes corresponding to a plurality of axial locations in the drive transmission section of the driver bit.

2. The driver bit quality determination device according to claim 1, characterized in that it includes a quality determination means for determining whether the shape of the drive transmission part of the driver bit is good or bad by comparing the amount of insertion when a suitable driver bit is fitted into each inspection hole with the amount of insertion when the driver bit to be inspected is fitted into each inspection hole sequentially with the reference insertion amount.

3. A method for determining the quality of the shape of a drive transmission part of a driver bit, which is equipped with a tapered drive transmission part that can engage with the drive part of a screw, A method for determining the quality of a driver bit, characterized by preparing an inspection jig having multiple inspection holes corresponding to multiple axial locations of the drive transmission part of the driver bit, sequentially fitting the drive transmission part of the driver bit into each inspection hole of the inspection jig, measuring the amount of insertion as the actual insertion amount, comparing this actual insertion amount with a reference insertion amount which is a preset appropriate amount of insertion of the driver bit into the inspection hole, and determining the quality of the shape of the drive transmission part of the driver bit measured by the actual insertion amount from the comparison result.

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