JPH0155095B2 - - Google Patents

Abstract

PURPOSE:To raise the quality and yield of products as well as to prevent maloperations by a method in which a lock mechanism to automatically control heating and bonding operations is mechanically incorporated, and before or after the lapse of a given period of time, the operation of torque wrench is interrupted. CONSTITUTION:A movable clamp 3 is slid, the ends of pipes P1 and P2 are contacted with a heater, a torque wrench 20 is operated, and a given pressing force is applied to the pipes P1 and P2. A switcher is turned on, a timer T1 is operated, and a locking is held. At the same time as a heating time t1 is passed, locking is released, the switcher is turned off when the torque wrench 20 is returned, the switch 61 is excited, locking is turned on, and at the same time the timer T2 begins to operate. Locking is held for a time t2 period and then released, and heating is ended. The heater is removed, the timer T4 begins to operate, and at the same time as a time t3 period is passed, locking is released. When more than the time t3 period is passed, the torque wrench is again locked and becomes unreleasable.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a butt fusion machine for butting and welding resin pipes (eg, polyethylene pipes or plastic pipes) together.

In recent years, resin pipes such as polyethylene have been increasingly used as gas pipes in place of conventional metal pipes. The resin pipes are connected to each other by heating and fusing the opposing end surfaces of the resin pipes. In other words, when butting and welding tubes together,
A method is used in which the joint surfaces of both tubes are heated and melted using a heater, and the heated and melted surfaces are pressed together under a predetermined pressure. The pair of tubes crimped in this manner are completely integrated and connected after being allowed to cool for a certain period of time.

Therefore, in such a fusion work, it is very important to control the heating melting time by the heater and the pressure bonding time between the molten surfaces. Optimum values for these heating and melting times and crimping times are determined in advance according to the pipe diameter, etc. Especially in the case of heating and melting times, the reliability of the fused part can be improved even if the heating and melting times are longer or shorter than the predetermined optimal times. There is a greater possibility that the product will be damaged and the product will be defective. However,
The work procedure for butt welding is to place a heater between opposing end surfaces of a pair of pipes to be fused, bring the pipes closer to each other in the axial direction, and press them against the heater for a predetermined amount of time until the opposing end surfaces of the pipes melt. Once heated, both pipes are separated from the heater, then the heater is quickly removed, and the pipes are moved toward each other again to bring the molten surfaces into contact with each other with a predetermined pressing force for a predetermined period of time, but all of this work is done manually. Therefore, it is completely impossible for a single worker to do it. Therefore, a worker who manages the heating melting time and the crimping time has conventionally been required separately from the worker who installs and removes the heater or crimps the pipe, and therefore a minimum of two workers have been required. If the crimping time is shorter than the predetermined value, the connection between the pipes will be incomplete, and if the heating time is longer than the predetermined time, not only will the melting range expand more than necessary, but the amount of melting will become too large, and the connection between the pipes will be incomplete. If it is shorter than the time, a sufficient amount of melting cannot be obtained and welding becomes impossible. In practice, the heating time and crimping time are managed by relying on the primitive method of calling with a stopwatch, so that sometimes the stopwatch operator becomes distracted and the heating time exceeds a predetermined value. Furthermore, the need for a separate worker dedicated to time management also poses an undesirable problem in terms of labor saving and automation.

Furthermore, in practice, when performing a joining operation to ensure the joining of pipes, the first step is to flatten the end surfaces of the pipes, that is, to
It is necessary to heat the end face of the pipe while pressing it against the heater with a predetermined force to make it a uniform vertical flat surface, and it is also necessary to control the pressurizing time and force.

The object of the present invention is to incorporate a lock mechanism that automatically controls heating work and crimping work into a machine, and to automatically turn on and off the lock mechanism in conjunction with heating melting work and crimping work, and to control the lock mechanism automatically when a predetermined period of time has elapsed. By not allowing subsequent work to be performed until later or after a predetermined period of time has elapsed, work errors due to worker skill or carelessness are prevented from occurring, thereby increasing product quality and yield. There is a particular thing.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a butt fusion machine according to the present invention will be described in detail with reference to the accompanying drawings.

Figures 1 and 2 show an overview of the overall butt fusion machine for butt fusion joining polyethylene pipes P ₁ and P ₂ , which serve as city gas conduits, to their end faces (butt fusion joining). A clamp 3 holds the pipe _P1 on one side, and a clamp (vise) holds the other pipe _P2 , and the clamps 2 and 3 have split rings 4a and 4b. One of the two split rings 4b is formed integrally with the vise body, and the other ring 4a is pivotally connected thereto by a pivot pin 5 so as to be expandable. The pipes P ₁ and P ₂ are sandwiched between the split rings 4a and 4b, and a male threaded portion 6 is provided on one of the split rings 4b.
The tube is clamped by tightening the female screw 7 with a handle that is screwed into the tube. Therefore ring 4a
Shoulder portion 14 pressed by internally threaded member 7
is provided. The clamp ring 4a can be opened to the other side (backward side in the drawing) by loosening the screw 7 and tilting it forward in FIG.

One of the clamps 2 and 3 is fixed to a base (bed) 1, and the lower part (slider) 4b of the other clamp 3 is fixed to a pair of parallel guide rods 1.
It is attached so that it can slide freely along the lines 0 and 10.
That is, the clamp 3 constitutes a carriage that approaches and moves away from the clamp 2. The guide rods 10, 10 extend parallel to the pipe axis and are fixedly held by a bracket 11 provided on the base 1.

For example, a heater (not shown) on a disk is placed between both clamps 2 and 3 when required, and the pipes P ₁ and P ₂ are
By pressing the joint end surfaces of the pipes P ₁ and P 2 against the heater face of the heater, the end surfaces of the pipes P 1 and P ₂ are heated and melted.

In addition, 50 is a chamfering machine for cutting the tube end face to make a uniform vertical flat surface prior to fusion joining the tubes.

The chamfering machine 50 is rotatably and slidably attached to one of the rods 10, for example.

The chamfering machine 50 can take a chamfering position located between both clamps (FIG. 1) by means of a handle 55, and a retracted position (not shown) away from both clamps. The chamfering machine 50 has a cutting blade (not shown) that is rotationally driven by a motor 53 via a reduction gear (not shown), thereby cutting the pipes P ₁ ,
Chamfer the end face of _P2 . Since the chamfering machine 50 itself has nothing to do with the present invention, further explanation will be omitted.

A torque wrench 20 for pressing the clamp 3 toward the clamp 2 has an arm 22 pivotally connected to a pin 25 of the base 1 via a link 21 having an elongated hole 23. Arm 22 of torque wrench 20
The rotation fulcrum is formed by a pivot pin 29 pivotally connected to the slider 4b of the movable clamp 3. Therefore, the arm 22 can rotate clockwise and counterclockwise about the pivot pin 29 by the length of the long axis of the elongated hole 23. The slider 4b slides back and forth on the guide rod 10 by rotating the arm 22. A torque scale plate 33 is attached near the upper end handle 31 of the torque wrench 20. The scale of the torque scale plate 33 can be read by a pointer 37 fixed to the base end of the torque wrench. The set torque value of the torque wrench is held by a retainer 41. Retainer 4
1 has an outer cylinder 47 pivotally connected to one end of the guide rod 10 by a pivot pin 45, and a rod 41 fixed to the upper end of the torque wrench by a pivot pin 46 and slidably disposed within the outer cylinder 47. . Outer cylinder 47
A fixing bolt 43 is attached to the holder, and by tightening the fixing bolt 43, the outer cylinder 47 and the rod 41 are fixed, and the torque wrench is held at a predetermined torque value.

The above description is a typical structure of a butt fusion machine with a torque wrench.

In the above-mentioned butt fusion machine, a torque wrench is used to apply a predetermined pressure force for a predetermined period of time when the heater is used to heat and pressurize the end surface of the pipe for surface leveling and when the pipes are crimped together. Pipe P ₂ may be crimped onto pipe P ₁ after the predetermined time has elapsed, or the heater may be removed before the predetermined time due to worker carelessness or inexperience, resulting in insufficient leveling or heating melting. There were problems such as pipes being fused together if this was not done. All of these degrade the quality of the product and essentially necessitate redoing the fusing operation. In particular, if the heater removal work is not done quickly within a predetermined time, the fused surface of the pipe that has been heated and melted will cool rapidly, so it is necessary to strictly manage the time. In addition, if the pressing force is not released once the surface leveling by heating and pressurizing melting is completed, the pipe melted surfaces will be pressed against each other more and more, resulting in pipes P ₁ and P ₂
becomes gradually shorter. Therefore, the heating and pressure melting time _t1 is extremely short (usually 7~
10sec.). However, this t ₁ hour is insufficient heating time to fuse the pipes P ₁ and P ₂ . That is, after the pressing force is released, it is necessary to further heat and melt the pipes P ₁ and P ₂ for a predetermined time t ₂ (≈40 to 60) while keeping them in light contact with the heater.

Conventionally, time management for each task as described above was entirely dependent on the judgment of the worker, resulting in various problems as described above.

According to the present invention, in order to solve this problem, a lock mechanism is provided to prevent the next operation from being performed until or after a predetermined period of time has elapsed. This locking mechanism forces the torque wrench to become inoperable.

The locking mechanism according to the invention includes a locking pawl member 63 driven by an actuator in the form of a solenoid switch 61, for example. Rod 41
External teeth 44 such as screws, irregularities, or notches are formed on the outer periphery of the claw member 63, and teeth 64 that engage with these are also formed on the claw member 63. The outer cylinder 47 has a claw member 6.
A horizontal hole 68 is formed in a portion corresponding to the claw member 6.
3 can protrude into the interior through its transverse hole 68. The pawl member 63 is connected to the plunger 65 of the solenoid switch 61, and when the solenoid switch 61 is OFF, it is retracted into a guide member 70 fixed to the outer periphery of the outer cylinder 47, and when the solenoid switch 61 is energized, it protrudes and engages the rod 41. meshes with the external teeth 44 of. Once the pawl member 63 and the external teeth of the rod 41 are engaged, the torque wrench can no longer be operated. This locks the torque wrench. In the present invention, the torque wrench is locked by the solenoid switch 61 at a predetermined time, so the fixing bolt 43 can be omitted.

A control signal for turning on and off the solenoid switch 61 is given by a switch means formed by a dog 65 formed at the upper end of the pointer 37 of the torque wrench and a micro switch 67 attached to the torque scale plate 33. The dog 68 and the micro switch 69 are connected to large diameter pipes P ₁ and 69, respectively.
This is for _P2 and is not essential to the basic concept of the present invention. When the torque wrench is operated to reach a predetermined torque value, the dog 65 kicks the contact 66 of the micro switch 67 and sends the signal to the control box 150.

FIG. 5 shows an example of the control box 150. First, timers T ₁ , T ₂ , T ₃ , T ₄ ,
By _T5 , heating and pressurizing melting time t ₁ , heating holding (heating and melting time after pressing force is released) time t ₂ , heater removal time
t ₂ ', crimping time t ₃ and cooling time t ₄ are set. The cooling time _t4 may be, for example, 180 seconds or more. In the illustrated embodiment, the changeover switch 15 is
3 allows two types of time settings (t ₂ = 40 or 60, t ₃ =
40 or 60 or more), but it is not necessary to do so. Note that 151 is a power switch.

The operation of the locking mechanism according to the invention is as follows.

After setting the heater in a predetermined position, slide the slider 4b of the movable clamp 3 along the guide rod 3 to bring the end surfaces of the pipes P ₁ and P ₂ into contact with the heater (the heater is placed in a chamfering machine 50 shown in FIG. 1). ) Next, operate the torque wrench and tighten the pipe.
Apply a predetermined pressing force to P ₁ and P ₂ . At this time, the micro switch MSW 67 is turned on by the dog 65, and as a result, the lock pin pawl member 63 projects to the lock position. At the same time, timer _T1 is activated and the locked position is maintained until the set time _t1 is reached. Therefore, even if the operator mistakenly tries to return the torque wrench to stop the heating and pressurizing melting before time t ₁ seconds has elapsed, the torque wrench cannot be moved. At the same time as the predetermined heating, pressurizing and melting time _t1 has elapsed, the solenoid switch 61 is turned off and the lock mechanism is released. As a result, the operator can return the torque wrench to its initial position at any time. The above heating and pressurizing program is as shown in FIG. 6A.

Next, by returning the torque wrench to the initial position, the micro switch (MSW) 67 is turned off again. When the micro switch 67 is turned off, the next heating holding program (heating and melting after the pressure is released) starts.

When the micro switch 67 is turned off, the solenoid switch 61 is energized and the lock pawl 63 protrudes, turning the lock ON. At the same time, timer _T2 starts and remains locked until _t2 seconds have elapsed. Therefore, the operator cannot bring the torque wrench into the working position before the predetermined time t ₂ has elapsed. t After ₂ hours, the lock is released and the heating melting program ends.

Next, in order to remove the heater, the movable lamp 3 is moved along the guide rod 10 and separated from the heater. After removing the heater, move the slider 4b again to the guide rod 1.
0 along the pipe P ₂ close to the fixed clamp part 2.
is in contact with pipe P ₁ . Then, when the torque wrench is activated again, pipe P ₂ is pressed against pipe P ₁ with the required force. At this time, the micro switch 61 is turned on again and a few seconds later the lock pawl 63 projects to the lock position. At the same time, timer _T4 starts and counts crimping time _t3 . Therefore, since the lock is not released until the predetermined time _t3 has elapsed, the torque wrench cannot be returned to the initial position before the crimping time is completed due to operator carelessness. t After ₃ hours, the lock will be released and you can return the torque wrench to its initial position and release the crimp force. At the same time as this lock release, timer _T5 starts and counts cooling (cooling) time _t4 . Timer _T5 is simply used to inform the operator whether the predetermined cooling time has elapsed or not.

On the other hand, if it takes time to remove the heater after heating and melting is completed, and more than t' ₂ hours elapse before pipe _P2 is crimped to the melting surface of pipe _P1 , a signal is sent to the solenoid switch 61 and the switch is automatically turned off. The lock mechanism is activated automatically. The torque wrench can therefore no longer be activated and therefore pipe P ₂ cannot be crimped onto pipe P ₁ .
In this way, if t′ ₂ hours or more have elapsed, the product can be rejected as a defective product or the product can be heated and melted again. In that case (when t' ₂ hours have passed), it is preferable to notify the operator by displaying a buzzer or lamp.

Thus, according to the present invention, the heating time and the crimping time can be accurately controlled by the lock mechanism that is linked to the heating operation and the crimping operation, respectively, thereby eliminating the problems mentioned at the beginning due to worker's carelessness or erroneous sensitivity. I can solve the points.

[Brief explanation of drawings]

Figure 1 is a front view showing the overall configuration of a butt fusion machine according to the present invention, Figure 2 is a plan view of Figure 1, Figure 3 is a left side view of Figure 1, and Figure 4 is Figure 3. FIG. 5 is a view showing the display panel section of the control box shown in FIG. 4, and FIGS. 6A, B, and C are flowcharts of the operation of the butt fusion machine according to the present invention. 1... Machine base, 2... Fixed clamp, 3... Movable clamp, 4b... Slider, 10... Guide rod,
20...Torque wrench, 61...Solenoid switch, 63...Lock claw member, 67...Micro switch.

Claims (1)

[Claims] 1. A fixed clamp that holds one resin pipe to be fused and a movable clamp that holds the other resin pipe are connected by a guide rod that extends in a direction parallel to the pipe axis between the two clamps, and the clamp is connected to the guide rod. The movable clamp is made to be able to approach and separate from the fixed clamp along the same line, and is equipped with a torque wrench that applies a predetermined pressing force to the movable clamp. In a butt fusion machine for resin pipes, which welds a pair of resin pipes by removing the heater and pressing the melted surfaces of the pipes together for a predetermined period of time, the movable clamp approaches and leaves the movable clamp, and the torque wrench operates and disables. 1. A butt fusion machine for resin pipes, comprising a detection means for detecting a torque wrench, and a lock means for preventing operation of a torque wrench at a predetermined time in response to a signal from the detection means.