JPH068331A - Control unit of resin pipe fusional bonding machine - Google Patents

Abstract

PURPOSE:To provide a control unit capable of automation controlling the fusional bonding work of a resin pipe substantially completely. CONSTITUTION:The resin pipe fusional bonding machine includes a movable clamp 17 and a stationary clamp 15 that hold resin pipes P1, P2 and can relatively move to and away from each other, and a double acting fluid pressure cylinder 23 having a piston rod for permitting the movable clamp to reciprocate, wherein the control unit has a location detecting switch LS1 secured to the piston rod. an actuator 31 attached to the movable clamp for actuating the location detecting switch in accordance with the location of the movable clamp, a timer for starting count in accordance with an output signal of the location detecting switch, and a fluid pressure circuit 37 for controlling a supply of fluid pressure to the fluid pressure cylinder in accordance with the count of the timer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to, for example, a resin pipe (eg, polyethylene pipe or other plastic pipe).
The present invention relates to a control device for a fusing operation in a butt fusing machine for abutting and fusing each other. Incidentally, the pipe fusion machine is a butt fusion machine (fusion between pipes), a saddle fusion machine (fusion between saddle and pipe), a socket fusion machine (fusion between socket and pipe), depending on its application. Although the concept of the present invention can be applied to all such fusion machines, the butt fusion machine will be described as an example for convenience.

[0002]

2. Description of the Related Art In recent years, resin pipes such as polyethylene having excellent earthquake resistance have been widely used as gas pipes instead of conventional metal pipes. Then, such resin pipes are connected to each other by heating and melting the opposite end faces of the resin pipes. That is, a heater is placed between the opposing end faces of a pair of resin pipes to be fused, the pipes are axially moved closer to each other and pressed against the heater face, and the pipes are separated from the heater after heating for a predetermined time until the opposing end faces of the pipes melt Then, after quickly removing the heater, the tubes are again moved toward each other to bring the molten surfaces into pressure contact with each other with a predetermined pressing force for a predetermined time. The pair of tubes thus crimped together are completely integrated after being left to cool for a certain period of time.

When the tube is pressed against the heater surface to be heated and melted, the tube is pressed against the heater surface while a predetermined pressing force is applied for the first predetermined time so that the tube-opposing end surface is chamfered (pressurized melting). Releases the pressing force and brings the tube into contact with the heater surface for a predetermined period of time with the pressing force being substantially zero (heating and holding) to heat and melt the tube end surface. In other words, if the pressing force is not released after the surface facing (opposing melting) of the pipe facing end faces is completed, the pipe end melting faces are pressed against each other more and more, and both pipes become shorter. Therefore, the pressurizing time must be the short time required for surfacing. However, this short time is insufficient heating time for fusing the two tubes. That is,
After releasing the pressing force, it is necessary to heat and melt (heat and hold) for a predetermined time (much longer than the pressurizing time) while the tube is lightly contacted with the heater. The pressure and melting time, the pressure, the heating and holding time, etc. differ depending on the type (diameter) of the tube.

[0004]

However, in the conventional fusing machine, an apparatus for controlling the above-mentioned series of fusing operations substantially completely automatically, including control of the pressure fusing time and pressure, and the heating and holding time, is not available. Not realized. SUMMARY OF THE INVENTION An object of the present invention is to provide a control device which enables substantially completely automatic control of the above fusion work.

[0005]

In order to achieve the above object, a relative approach for holding a pair of resin pipes to be fused,
A resin pipe fusion machine according to the present invention, comprising a movable clamp and a fixed clamp that can be separated from each other, and a double-acting fluid pressure cylinder that has a piston rod connected to the movable clamp and that reciprocates the movable clamp. The control device of the landing machine includes a position detection switch attached to the piston rod of the fluid pressure cylinder or a movable portion integrally with the piston rod, and a position detection switch attached to the movable clamp or a movable portion integrally with the movable clamp, depending on the position of the movable clamp. An actuator that operates the detection switch, a timer that starts counting according to the output signal of the position detection switch, and a switching control valve device that controls the supply of fluid pressure to the fluid pressure cylinder according to the count of the timer And a fluid pressure circuit for selectively supplying fluid pressure to the fluid pressure cylinder. .

Preferably, the movable clamp or a portion movable integrally with the movable clamp is provided with a plurality of actuators for operating the position detection switch at a plurality of different positions.
Further, the piston rod of the fluid pressure cylinder or a portion movable integrally with the piston rod may be provided with a second position detection switch for detecting the initial position thereof. Preferably,
A spring having a predetermined initial load is interposed between the piston rod of the fluid pressure cylinder and the movable clamp.
A third detection switch for detecting the diameter of the pipe can be attached to one of the clamps.

[0007]

The pair of resin pipes to be fused are held by the movable clamp and the fixed clamp that can relatively approach and separate from each other. The movable clamp is moved toward and away from the fixed clamp by a double-acting hydraulic cylinder. The position detection switch mounted on the piston rod of the fluid pressure operating cylinder or a portion movable integrally with the piston operates the movable clamp or the position detection switch mounted on a movable portion integrally with it by contacting the actuator. Therefore, the relative position to the movable clamp can be detected. Detecting the position of the movable clamp means detecting the relative position with respect to the fixed clamp, and as a result, the pressing force can be detected.

After a lapse of a predetermined timer set time, that is, after a lapse of a predetermined pressurizing and melting time, the working cylinder is released to release the pressing force. Further, in this state, the tube ends are brought into contact with the heater for a predetermined period of time with the applied pressure being substantially zero. When the heating and melting for a predetermined time is completed in this way, the working cylinder is moved in the reverse direction to separate the movable clamp from the fixed clamp and separate the tube ends from each other. Then, after quickly removing the heater, the actuating cylinder is actuated again to press the melted pipe ends together with a predetermined pressing force. After a lapse of a predetermined time, the tube ends are completely fused.

When a plurality of actuators are provided, the contact position of the position detection switch with respect to them is different, so that the pressing force by the operating cylinder can be changed. The second detection switch detects the initial position of the movable clamp,
The third detection switch detects the diameter of the tube.

[0010]

EXAMPLES Examples of the present invention will be described in detail below. FIG. 1 shows the basic configuration of the present invention. In the figure, a pair of plastic pipes P1 and P2 to be fused are a fixed clamp 15 integrally fixed to a fuser main body (machine stand) 11 (only the frame is shown), and a pair of plastic pipes P1 and P2 provided on the machine stand 11. Guide bar 13
And a movable clamp 17 that is movable in a direction parallel to the axis of the pipe P. That is, the movable clamp 1
7, therefore the tube P2 supported by it is fixed clamp 1
5, thus approaching the pipe P1 supported by it,
Separate.

When the tubes P1 and P2 are fused, as described above, the heater plate H is sandwiched between the tubes P1 and P2, and
The tube ends of 1 and P2 are pressed against both sides of the heater for a predetermined time in a pressurized state, and after this predetermined pressurizing and holding time T1 elapses, the pressure is released and the pressure is maintained at zero for a further predetermined time T2. Then, the heater H is quickly removed, and the melted tube ends are pressed against each other for a predetermined time T3 with a predetermined pressure. The pair of pipes P thus crimped in this way are completely integrated after being left to cool for a certain period of time.

The movable clamp 17 is connected via a spring 21 to a piston rod 25 of a cylinder device 23 which is integrally mounted on (the flange 12 of) the machine base 11. In the illustrated embodiment, a plate-shaped pusher 27 is fixed to the tip of the piston rod 25, and the spring 21 is provided between the pusher 27 and the movable clamp 17, but the pusher 27 is not necessarily provided. Thus, the expansion / contraction force of the piston rod 25 acts on the movable clamp 17 via the pusher 27 and the spring 21. The reason for interposing the spring 21 will be described later.

Two limit switches L are provided on the piston rod 25 or an integral part thereof, for example, the pusher 27.
S1 and LS2 are attached. The first limit switch LS1 has three dogs 31a, 31b, 31c as described later.
The second limit switch LS2 is for detecting the position of the pusher 27 when the pusher 27 comes into contact with the pusher 27.
Is for detecting the return of the pusher 27, that is, the piston rod 25 to the initial position by coming into contact with (the flange 12 of) the machine base 11 when returning to the initial position shown in FIG. On the other hand, the fixed clamp 15 is provided with a third limit switch LS3 to detect the type of the pipe P, that is, the pipe diameter. That is, when there are two types of pipe diameters to be fused, for example, a large diameter pipe, the limit switch LS3 contacts the outer circumference of the pipe, and a small diameter pipe has a limit switch LS3.
By not touching the pipe, the diameter of the pipe set in the clamp can be determined. If there are three or more pipe diameters, the number of third limit switches LS may be increased accordingly.

As described above, the movable clamp 17 is fixedly provided with the dog bar 33 extending in the direction parallel to the tube axis, and the three dogs 31a, 31b and 31c are attached to the dog bar 33 at predetermined intervals. The first limit switch LS1 selectively contacts the dogs 31a, 31b, 31c to detect the relative position of the pusher 27, that is, the piston rod 25 with respect to the movable clamp. The detection signals of the first, second and third limit switches LS1, LS2, LS3 are sent to the controller 35.

Although the cylinder device 23 is a double-acting hydraulic cylinder in the illustrated embodiment, any other fluid pressure cylinder such as an air cylinder can be used. The cylinder device 23 is connected to a hydraulic circuit 37. The hydraulic circuit 37 basically comprises two solenoid-operated hydraulic control valves 51, 53 known per se. In the illustrated embodiment, the first solenoid-operated hydraulic control valve 51 is in the neutral position and all ports are tanks. It is a double-ended solenoid spring center type 4-port 3-way valve (3-position switching valve) connected to 57, and the second solenoid actuated hydraulic control valve 53 is a single solenoid spring offset type 2-port 2-way valve which is closed in a steady state. Is. The hydraulic pump 55 driven by the motor M supplies and discharges oil in the tank 57 and drives and controls the hydraulic cylinder 23 via the hydraulic control valves 51 and 53 as needed. Incidentally, 59 is a relief valve, 61,
63 is a check valve operated by pilot pressure (shown by imaginary lines PP1 and PP2), and 65 is a speed control valve (flow control valve)
Is.

The control device constructed as described above operates as follows. In the following description, the dog 31 is the second dog 31.
Only b is relevant. First, when starting the fusion work, the main switch MS of the control device is operated. As a result, the hydraulic pump 55 operates, and at the same time, the first solenoid SOL1 of the first solenoid operated hydraulic control valve 51 operates to move the valve spool to the right in FIG.
It comes to the first position shown in (a). As a result, the hydraulic pump 5
5, the hydraulic pressure is supplied to the pressure chamber on the left side of the piston of the hydraulic cylinder 23 via the first hydraulic control valve 51, and pushes the piston rod 25 to the right. As a result, the movable clamp 17 moves rightward toward the fixed clamp 15 via the spring 21, and sandwiches the heater H inserted between the clamps (FIG. 2A). From this state (the pressure to the heater H has not yet been generated in this state), the piston rod 2
When 5 further moves to the right while compressing the spring 21, the pipe P applies a predetermined pressing force corresponding to the compressive force of the spring 21 to the heater H. This is pressure retention (Fig. 2
(B)). The spring 21 is provided to generate this pressing force.

When the spring 21 is compressed by a predetermined amount, FIG.
As shown in (b), the first limit switch LS1 is
It is beaten by Dog 31B. As a result, the first timer (for pressurizing and melting time control) TM1 of the controller operates based on the signal from the first limit switch LS1. At the same time, the first solenoid SOL1 is turned off and the hydraulic pump 55 is also turned off. The first timer TM1 has a predetermined time t1.
After a lapse of time, that is, when the pressurizing and melting time ends, the third solenoid SOL3 is turned on. At this time, the cylinder 23
Since the oil in the left pressure chamber is returned to the tank 57 via the third solenoid 3, the piston rod 25 is moved leftward by the spring 21 until the spring 21 in the compressed state becomes free. As a result, the pressure applied by the spring disappears, and the heating-holding state is entered. After the pressure disappears (for example,
About 3 seconds after SOL3 is turned on) 3rd solenoid SOL
3 is turned off to hold the piston rod. (Fig. 3
(A))

The second timer TM2 starts counting at the same time when the first timer TM1 elapses a predetermined time t1. When the set time t2 of the second timer TM2 elapses, that is, when the heating holding time elapses, the hydraulic pump 55 is turned back on. Then, at the same time, the second solenoid SOL2 is actuated, and the first hydraulic control valve 51 moves to the second solenoid shown in FIG.
Brought to position. As a result, the piston rod 25 of the cylinder 23 moves to the left, and the movable clamp 1
7 moves to the left and separates from the fixed clamp 15. As a result, the heater H can be removed. The heater H may be removed by an operator, but may be dropped by its own weight when the movable clamp 17 separates from the fixed clamp, as described later.

When the movable clamp 17 returns to the initial position shown in FIG. 1, the second limit switch LS2 comes into contact with (the flange 12 of) the machine base 11 so that the return to the initial position can be detected. Based on the detection signal, the second solenoid SOL2 is turned off and the first solenoid SOL2 is turned off.
1 is activated. The operation of the first solenoid SOL1 can also be performed manually. As a result, the state shown in FIG. 2A is restored again, and the movable clamp 17 moves rightward so that the melting ends of the pipes P1 and P2 contact each other. still,
In this case, since the heater H does not exist, the piston rod 25 is moved by an amount corresponding to the thickness of the heater H in FIG.
Although larger than (a), since the spring 21 compresses after the melting ends of the pipes P1 and P2 contact each other, the pressing force is basically the same as the pressing force to the heater. This is because the pressure applied by the heater during pressure melting and the pressure applied during pressure bonding between the ends of the melting pipe are generally set equal.

If it is necessary to make the pressure applied by the heater under pressure and melting different from the pressure applied during the fusion of the ends of the melting tubes, for example, another limit switch (not shown) is used. ) Is provided on the movable clamp so that the piston rod is moved until its limit switch is hit by the dog 31b or a dog (not shown) provided separately. The first limit switch LS1 is dog 3
When struck by the second time by 1b, the third timer TM3 starts counting. Therefore, although not shown in the drawing, it is necessary to check whether the number of times the first limit switch LS1 is operated by the dog 31b is the first or second time under the control of the controller 35.

At the same time, the hydraulic pump 55 and the first solenoid SOL1 are turned off, and the cylinder 23 is held at that position. That is, the pressing force is kept constant. Third
When the set time t3 of the timer TM3 elapses, that is, when the tube end crimping time ends, the fourth timer TM4 starts counting. At the same time, the third solenoid SOL3 is turned off, the piston rod retracts, and the pressing force disappears as described above. After the pressing force disappears (for example, about 3 seconds after SOL3 is turned off), the third solenoid SOL3 is turned off to hold the piston rod. When the fourth timer TM4 has passed the predetermined time t4, that is, when the cooling of the fused portion is finished, all the fusion work is finished. Be sure to remove the resin tube from the fusion machine before retracting the piston rod.

4 and 5 show an example of an automatic heater H removing device. This automatic removal device itself is, for example, in actual exploitation 57-1
It is a known one disclosed in No. 67814. After removing the heater, it is important to press the ends of the melting tubes together quickly to fuse them. The reason for this is that the pipe end heated to a predetermined temperature at a sharp temperature is cooled rapidly and the fusion effect is lowered.

The heater H is basically a heater block 71 having a built-in heater and a base 7 supporting the heater block.
3 and 3. The heater block 71 itself is known and has a substantially circular plate shape as shown in the figure, and the whole functions as a heater. Reference numeral 75 is a cable for supplying power to the heater block 71. A handle 77 is integrally formed with the heater block 71. The base 73 has an empty space 81 for accommodating the heater block 71 in the center thereof,
Heater block 7 in the retracted position (inoperative position)
1 is placed. The heater block 71 is a support shaft 8 extending between the placket arms 83 formed on the base 73.
5, the support shaft 85 is rotatably fitted in a shaft hole 87 formed in the placket arm 83. Therefore, the heater block 71 is rotatable with the support shaft 85. Alternatively, the support shaft 85 may be fixed to the shaft hole 87 of the placket arm 83 to rotatably support the heater block 71 with respect to the support shaft 85. The heater block 71 is always brought to the retracted position 71 'by its own weight. Pipes P ₁ , P
_The heater block 71, which has been heated to a predetermined temperature, is inserted between the _two . The heater block 71 can be easily brought to the solid line position (fusion position) in FIG. 4 simply by holding the grip 77 and applying a force F in the direction of the arrow. In this state, both pipes P ₁ , P
₂ is pressed against the heater block 71 and the heater block 71
To pinch. At this time, even if the grip 77 is released, the heater block 71 is held at the fusion bonding position by the pressing force of the pipes P ₁ and P ₂ . When the heating of the tube ends is completed, the pressing force of the tubes P ₁ and P ₂ is released, and the heater block 71 falls (rotates) to its retracted position by its own weight. as a result,
The two pipes P ₁ and P ₂ are completely fused by pressing the pipe ends again quickly.

The third limit switch LS3 is provided at a position where it contacts a large-diameter pipe but does not contact a small-diameter pipe when the diameter of the pipe P1 is, for example, two. Alternatively, separately from this, it is also possible to provide two dedicated limit switches for each of the large diameter and the small diameter. If there are two or more types (diameters) of pipes, each pipe can be detected by increasing the number of limit switches.

Preferably, a plurality of dogs 31 (31a, 31b, 31c) are provided as shown in the figure, and the dog to be used is preliminarily determined in accordance with the type of pipe diameter, material, etc. The pressing force of can be set to multiple types. Alternatively, separately from this, if the dog 31 is attached to the dog bar 33 so that the position of the dog 31 can be adjusted, the pressing force at the time of pressurizing and holding can be arbitrarily adjusted and set by a single dog.

[0026]

As described above, according to the present invention,
The fusion work of plastic pipes can be almost completely automated. Further, as a result, the skill of the worker is not reflected in the accuracy of the work, etc. Therefore, the fusion work of stable quality is always achieved.

[Brief description of drawings]

FIG. 1 is a schematic block diagram showing the basic concept of a control device for fusion bonding of resin pipes according to the present invention.

FIG. 2 is a hydraulic circuit diagram showing different operating positions of an operating cylinder used in the control device for fusion bonding of resin pipes according to the present invention.

3 is a hydraulic circuit diagram showing an operating position of an operating cylinder which is different from that in FIG. 2. FIG.

FIG. 4 is a cross-sectional view schematically showing an automatic heater removing device that can be used in the present invention.

FIG. 5 is a plan view of FIG.

[Explanation of symbols]

 11 ... Machine stand 15 ... Fixed clamp 17 ... Movable clamp 21 ... Spring 23 ... Cylinder 37 ... Hydraulic circuit 51, 53 ... Switching control valve device

[Procedure amendment]

[Submission date] February 17, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

When the spring 21 is compressed by a predetermined amount, FIG.
As shown in (b), the first limit switch LS1 is
It is hit by the dog 31b. As a result, the first timer (for pressurizing and melting time control) TM1 of the controller operates based on the signal from the first limit switch LS1. At the same time, the first solenoid SOL1 is turned off and the hydraulic pump 55 is also turned off. The first timer TM1 has a predetermined time t1.
After a lapse of time, that is, when the pressurizing and melting time ends, the third solenoid SOL3 is turned on. At this time, the cylinder 23
Since the oil in the left pressure chamber is returned to the tank 57 via the third solenoid 3, the piston rod 25 is moved leftward by the spring 21 until the spring 21 in the compressed state becomes free. As a result, the pressure applied by the spring disappears, and the heating and holding state is entered. After the pressure disappears (for example,
About 3 seconds after SOL3 is turned on) 3rd solenoid SOL
3 is turned off to hold the piston rod (Fig. 3
(A)). Since the pipe melts during pressure melting (and pressure bonding), even if the piston rod 25 is fixed, the movable clamp 17 is moved to the fixed clamp 15 side by the spring 21 by the amount of the melting portion of the pipe. To be Depending on the amount of movement of the movable clamp, the first limit switch LS1 may move to the dog 3
There is a possibility that it will go off from 1b and turn off. In such a case, that is, before the first timer TM1 times out, L
When S1 turns off, turn on the first solenoid SOL1.
N to move the piston rod 25 forward to extend the spring 21, that is, the first limit switch LS1 is turned on again.
It is also possible to perform control so as to compress until. Again, if LS1 is turned off for the same reason, similar control may be repeated. The above can be similarly applied, if necessary, during the pressure bonding work after heating and melting described later. ─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] April 28, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

The fluid pressure cylinder of the present invention may be either a hydraulic cylinder or an air cylinder. Especially, in the case of an air cylinder, even if the spring 21 is compressed by a predetermined amount, the switching valve (first solenoid) is not switched. By continuing to apply a constant air pressure, even if the pipe end is melted at the time of temporary heating and pressurizing and melting, the piston rod is advanced by that amount, so that a constant pressing force can continue to act without the spring 21 extending. I can. Further, in that case, the initial setting pressure of the air cylinder can be easily performed manually by using a scale needle and a scale plate (not shown) as is well known. In this case, the pressing force on the tube is determined by (spring contraction amount × spring constant). The second timer TM2 starts counting at the same time when the first timer TM1 has passed the predetermined time t1. When the set time t2 of the second timer TM2 elapses, that is, when the heating holding time elapses, the hydraulic pump 55.
Is turned back on. At the same time, the second solenoid SOL2 is actuated, and the first hydraulic control valve 51 moves to the position shown in FIG.
It is brought to the second position shown in (b). As a result, the piston rod 25 of the cylinder 23 moves to the left, and accordingly, the movable clamp 17 moves to the left and separates from the fixed clamp 15. As a result, the heater H can be removed.
The heater H may be removed by an operator, but may be dropped by its own weight when the movable clamp 17 separates from the fixed clamp, as described later.

Claims (5)

[Claims] 1. A pair of resin pipes (P1, P2) to be fused
A movable clamp (1
7), a fixed clamp (15), and a double-acting fluid pressure cylinder (23) having a piston rod (25) connected to a movable clamp to reciprocate the clamp, in a resin pipe fusion machine, A position detection switch (LS1) attached to a piston rod or a movable part integrally with it, and an actuator (LS1) attached to a movable clamp or a movable part integrally with it to operate the position detection switch according to the position of the movable clamp ( 31), a timer (TM) that starts counting according to the output signal of the position detection switch, and a switching control valve device (51) that controls the supply of fluid pressure to the fluid pressure cylinder according to the count of the timer. And a fluid pressure circuit (37) for selectively supplying fluid pressure to a fluid pressure cylinder. 2. A plurality of actuators (31a, 31b, 3) for operating the position detecting switch at a plurality of different positions on the movable clamp or a portion integrally movable with the movable clamp.
1c) is provided, The control device of Claim 1 characterized by the above-mentioned. 3. A piston rod of the fluid pressure cylinder or a portion movable integrally with the piston rod is provided with a second position detection switch (LS2) for detecting an initial position of the piston rod. The control device according to 1. 4. The control according to claim 1, 2 or 3, wherein a spring (21) having a predetermined initial load is interposed between the piston rod of the fluid pressure cylinder and the movable clamp. apparatus. 5. The control device according to claim 1, 2 or 3, wherein one of the clamps is provided with a third detection switch (LS3) for detecting the diameter of the pipe.