JPH04176573A - Automatic fastening and loosening method for screw member - Google Patents

Abstract

PURPOSE:To surely detect the fastening state of a screw member, by comparing the time value that the time value spent by one part of the screw member from its rotation start until its seating to the other part of the screw member and the time value spent until reaching the specified fastening torque after the seating, are added, with the measurement time value of the case of an actual fastening motion. CONSTITUTION:A set of screw members 16, 17 are automatically fastened and loosened, by rotating a socket 6, with the socket 6 of an automatic fastening and loosening device 4 being fitted to one part of the screw member 16, in a set of screw members 16, 17 screwable mutually. It is decided as to whether or not the fastening of a set of screw members 16, 17 is completed, by comparing the time value T added with the time value T1 spent by one part of the screw member 16 from its rotation start until its seating to the other part of the screw member 17 and the time value T2 spent until reaching the specified fastening torque after the seating, with the measurement time value T3 of the case of an actual fastening motion, in case of fastening a set of the screw members 16, 17.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to 1, for example, bolts and nuts that are assembly fasteners for divisible formwork used in forming concrete products such as balls and piles. The present invention relates to a method for automatically tightening and loosening a screw member.

[Prior Art] The above-mentioned formwork is made up of two long split molds each having a semicircular cross section, and the flanges protruding from both ends of the split molds in the longitudinal direction are overlapped.

It is formed to have a cylindrical shape with a substantially perfect circle in cross section.

A plurality of sets of bolts and nuts are used to fasten the split molds.

For tightening and loosening the bolts and nuts, an automatic tightening/loosening device such as an impact wrench is used, and the socket of the automatic tightening/loosening device is fitted into, for example, the nand, and the socket is rotated. The bolts and nuts are automatically tightened and loosened.

And as an automatic tightening/loosening device as mentioned above.

For example, the one disclosed in Japanese Patent Publication No. 60-23004 is known.

In the device disclosed in the above publication, when the screw member is automatically fastened, the device is controlled to be pulled up as if the screw member has been fastened by detecting a state in which the rotation of the socket has stopped.

In addition, in the NAND runner 1 shown in FIG. 6, which is an example of an automatic tightening/loosening device, when the main body 2 swings around a predetermined amount due to the reaction force acting on the main body 2 when the screw member is tightened to a predetermined torque, By detecting this with the limit switch 3, the fastening state is detected.

On the other hand, in the device disclosed in the above publication, when automatically loosening a screw member, the number of rotations of the socket is measured, and by detecting that this rotation has reached a predetermined number, the screw member is determined to have been loosened. The automatic tightening/loosening device is controlled to be pulled up.

[Problem to be solved by the invention]

However, in the automatic tightening/loosening device and nut runner 1 disclosed in the above-mentioned publication, 1, for example, when tightening a screw member, as mentioned above, the tightening that is applied when the rotation of the socket is stopped or when the rotation of this socket is stopped is caused by a reaction force. 1. For example, if the screw member deteriorates due to repeated use or if dirt gets stuck in the screw member due to use in a bad environment, 2. The screw member is determined to have been tightened completely. The rotation of the socket will stop even though the screw member is not fastened, and there is a possibility that it will be mistakenly detected that the screw member is fastened even though it is in an unfastened state.

On the other hand, when loosening a screw member in the automatic tightening/loosening device disclosed in the above publication, it is determined that the screw member has been loosened when the number of rotations of the socket reaches a predetermined value as described above. If it takes time for the socket to mate and the socket rotates more than necessary before it mates, the socket may rotate a predetermined number of times even though the screw member has not been completely loosened. This may cause a false detection that the screw member has been loosened.

Therefore, a first object of the present invention is to provide an automatic tightening/loosening method for a screw member that can reliably detect the fastened state of the screw member.

Furthermore, a second object of the present invention is to provide a method for automatically tightening and loosening a screw member that can reliably detect the loosened state of the screw member.

[Means for Solving the Problems] The first means adopted by the present invention in order to achieve the above-mentioned first object is summarized as follows.

A socket of an automatic tightening/loosening device is fitted into one screw member of a set of mutually threadable screw members, and by rotating the socket, the set of screw members is automatically tightened/loosened. When tightening the above-mentioned set of screw members in the automatic tightening/loosening method of screw members.

A time value that is the sum of the time value (T+) required for one screw member to seat against the other screw member from the start of rotation, and the time value (T2) required for one screw member to reach a predetermined tightening torque after seating. (T) and.

In the automatic tightening/loosening method of screw members, it is determined whether or not the fastening of the set of screw members is completed by comparing the measured time value (T3) during the actual fastening operation. be.

Furthermore, the second means adopted by the present invention in order to achieve the above-mentioned second object is that one of the screw members of a set of mutually threadable screw members is automatically attached to the screw member. In the method for automatically tightening and loosening a screw member, the set of screw members in a fastened state is automatically tightened and loosened by fitting a socket of a tightening and loosening device and rotating the socket. When loosening, the fitted state of the socket and one of the screw members is confirmed based on the reaction force acting on the automatic tightening/loosening device, and then the socket is rotated a preset number of times. This is a method for automatically tightening and loosening screw members, in which it is determined that the fastened state of a set of screw members is released.

[Example] Hereinafter, an example embodying the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention.

It should be noted that the following examples are examples embodying the present invention, and are not intended to limit the technical scope of the present invention.

Here, FIG. 1 shows an example of an automatic tightening/loosening device to which the automatic tightening/loosening method according to an embodiment of the present invention can be applied. (b) is a side view, Figure 2 is a front view of a screw member that can be tightened and loosened by the automatic tightening and loosening device, and Figure 3 is a tightening when tightening a screw member using the automatic tightening and loosening device. FIG. 4 is a graph showing the relationship between torque and rotation time of the screw member, and FIG. (a), (
b) is a perspective view of the main part of the socket rotation detection mechanism that can be applied to the automatic tightening/loosening device shown in Fig. 1, and Fig. 6 is a perspective view of the main part of the socket rotation detection mechanism that can be applied to the automatic tightening/loosening device shown in Fig. 1. It is a front view.

In the automatic tightening/loosening device 4 according to this embodiment, FIG. 1(a),
As shown in (g)), a socket 6 is fitted into the tip of a drive shaft 5 which is rotated by, for example, compressed air.
The rotation of the socket 6 is detected by a proximity switch 8 attached to the lower part of the main body 7, which detects the protrusion 9□ of the disc 9 attached above the drive shaft 5 and rotating together with the drive shaft 5. This is done by

Instead of the structure in which the protrusion 9 of the disk 9 is detected by the proximity swing 8 as described above, as shown in FIG. 5(a), a slit 10a of the disk 10 attached to the drive shaft 5 is Detected by a transmission type photoelectric switch 11, or as shown in Fig. 5)
For example, a white line 12 attached to the shaft portion of the drive shaft 5 may be detected by a reflective photoelectric switch 13 as shown in FIG.

Further, in the automatic tightening/loosening device 4, when the screw member fitted in the socket 6 is tightened to a predetermined torque, the main body 7 tends to swing around by a predetermined amount due to a reaction force acting on the main body 7. It is configured such that the limit switch 14 can detect this.

In the automatic tightening/loosening bag 24, when a set of screw members is fastened, the time required for one screw member to seat against the other screw member from the start of rotation, and a predetermined value after seating are determined. The time value obtained by adding the time value required to reach the tightening torque is compared with the measured time value until the tightening completion signal is output in 5 actual tightening operations, and the above set of screw members is tightened. It is determined whether or not the process has been completed.

The procedure of the above-mentioned fastening operation will be specifically explained based on FIGS. 2 and 3.

The screw members shown in FIG. 2 are bolts 16 and nuts 17 used when assembling and fastening the formwork 15 as described above, and are flanges protruding from each end of the 2-split molds 15□ and 16. It is attached to sandwich 18a and 18b.

The above bolt 16. Nando 17 is a 9, for example, window coarse screw, and its nominal diameter is W3/4. Pinch 2.54
It's 0 yen.

In Fig. 2, the bolt 16 has a right-hand thread and the tightening distance is 23 m, and the rotation speed of the socket 6 (drive shaft 5) under no load is 170 rpm with an air pressure of 4 kgf/c-d.
(2,833 rps).

In the above case, first divide one tightening allowance (23 turns) by the pitch of the screw member (2,540 turns), and then calculate the amount of rotation (9.05 turns) with the socket 6 in the no-load state. By dividing by the rotation speed (2,833 rps),
The time T required for the bolt 16 to seat on the upper surface of the flange 181 is 3.19 seconds (approximately 3 seconds).
ec) is obtained.

Assume that the time T2 required to reach a predetermined tightening torque after one sitting is, for example, 0.5 sec.

This value of T2 is added to the time required for seating, T, determined as described above.

Here, assuming that the safety factor is 1.2, the required tightening time T is 4.428 seconds (approximately 5 seconds).

The value of T becomes a reference value for determining whether or not the bolt 16 is fastened.

Then, the head of the bolt 16 is fitted into the socket 6 and rotated, and the time required until a tightening completion signal is detected is measured. The tightening completion signal is a signal that is output when the proximity switch 8 detects that the socket 60 has stopped rotating, or a signal that is output when the limit switch 14 detects a predetermined tightening torque. A signal is used.

The measured time value during the actual fastening operation measured as described above is compared with the above-mentioned required tightening time T (see Fig. 3), and the value of T3 is compared with the above-mentioned T.

If the value is lower than the value of volt 16 and nand 17,
If the value of T3 becomes larger than the value of T, it is determined that dirt or seizure has occurred between the bolts 16 and 16. It is determined that the threaded portion of the nut 17 is damaged or the bolt 16 is not accurately engaged with the nut 17, and that the condition is abnormal. and.

If the value of T is between T1 and T, it is determined that the screw member is properly fastened.

This result is notified to the operator by lighting or extinguishing the lamp 20 at the position corresponding to the defective screw member on the surface of the display 19 shown in FIG.

Therefore, in the method of this embodiment, it is possible to reliably detect whether or not the pin 16 is fastened to the nut 17.

Subsequently, the nut 17 is tightened using the automatic tightening/loosening device 4.
The procedure for loosening the bolt 16 which is in the fastened state will be explained with reference to FIG.

In this case, from the amount of tightening of the bolt 16 to the NAND 17, the amount of rotation of the bolt 16 is determined to be <9.05 as described above.
It is preset as rotation.

First, the socket 6 is pressed against the head of the pole 16 while being rotated in a direction opposite to that in the fastening operation. After confirming the fitted state between the socket 6 and the head of the bolt 1G, the socket 6 is rotated one rotation at a predetermined number of revolutions, so that the bolt 16 is fastened to the nut 17. is considered to have been cancelled.

In this case, the fitting state between the socket 6 and the head of the bolt 16 can be confirmed by checking the limit switch 1 when the main body 7 tries to swing around due to the reaction force acting on the main body 7.
This is done by detecting at step 4.

Therefore, according to the method of this embodiment, it is possible to reliably detect the state in which the bolt 16, which has been fastened to the nut 17, is loosened.

〔Effect of the invention〕

Since the method for automatically tightening and loosening a screw member according to the present invention is configured as described above, when the screw member is fastened, this fastening state can be reliably detected.

Furthermore, when the screw member is loosened, this loosened state can also be reliably detected.

[Brief explanation of the drawing]

FIG. 1 shows an example of an automatic tightening/loosening device to which the automatic tightening/loosening method according to an embodiment of the present invention can be applied; FIG. 1(a) is a perspective view and FIG. 1('b) is a perspective view. is a side view, Figure 2 is a front view of a screw member that can be tightened and loosened by the automatic tightening and loosening device, and Figure 3 is a diagram of the tightening torque and screw when tightening a screw member using the automatic tightening and loosening device. A graph showing the relationship with the rotation time of a member. FIG. 4 is a graph showing the relationship between the rotation speed and rotation time of the screw member when loosening the thread member using the automatic tightening/loosening device,
Figures 5(a) and 5(b) are perspective views of the main parts of a socket rotation detection mechanism that can be applied to the automatic tightening/loosening device shown in Figure 1, respectively, and Figure 6 shows whether the tightening/loosening condition is good or bad. FIG. FIG. 7 is a perspective view of a nut runner, which is an example of an automatic tightening/loosening device, for explaining the background art of the present invention. [Explanation of symbols] 4... Automatic cotton m device 5... Drive shaft 6...
Socket 7...Main body 8...Proximity switch 9...Disk 9,...Protrusion
10...Disk 10...Slint 11.13...Charging switch 12...White line 14...Liminth inch 16...Bolt 17...Nut 19...Indicator applicant Kobe Co., Ltd. ! ! ropeway

Claims (1)

[Claims] 1. A socket of an automatic tightening/loosening device is fitted into one screw member of a set of mutually threadable screw members, and the set of screws is rotated by rotating the socket. In the automatic tightening/loosening method of screw members that automatically tighten/unfasten members, when fastening the above set of screw members, the time required from the start of rotation until one screw member seats against the other screw member. The time value (T) that is the sum of the value (T_1) and the time value (T_2) required to reach the predetermined tightening torque after seating, and the measured time value (T_2) during the actual fastening operation.
3) to determine whether fastening of the set of screw members is completed or not. 2. A socket of an automatic tightening/loosening device is fitted into one screw member of a set of mutually threadable screw members, and the set of screw members is automatically tightened by rotating the socket. In the automatic tightening/loosening method of screw members to be loosened, when loosening the set of screw members in the fastened state, the fitted state of the socket and one screw member is determined based on the reaction force acting on the automatic tightening/loosening device. automatic tightening/loosening of screw members, characterized in that the socket is rotated a predetermined number of times after the above-mentioned set of screw members are confirmed to be unfastened. Method. 3. The above measured time value (T_3) is the above time value (T_1)
2. The automatic tightening/loosening method of a screw member according to claim 1, wherein the method determines that the fastening of the set of screw members is abnormal when the time value (T) becomes a value outside the range of the time value (T).