JPS6232829Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a butt fusion machine that butts and welds 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. That is, a heater is placed between opposing end surfaces of a pair of pipes to be fused, the pipes are moved axially close to each other, pressed against the heater surface, heated for a predetermined period of time until the opposing end surfaces of the pipes are melted, and then both pipes are separated from the heater. Then, after quickly removing the heater, the pipes are moved toward each other again, and the molten surfaces are brought into pressure contact with each other with a predetermined pressing force for a predetermined period of time. The pair of tubes crimped in this manner are completely joined together after being allowed to cool for a certain period of time.

A torque wrench is generally used as a pressurizing means when pressing the pipe against the heater surface and when pressing the molten end surfaces of the pipes together, but it is well known that the torque wrench is difficult to maintain the required torque stably. be. Furthermore, conventional torque wrenches are equipped with locking means for locking the torque wrench at a predetermined torque, but since this locking means is usually a locking bolt or the like, the operator has to tighten the locking bolt each time. Even while using the torque wrench, the pointer of the torque wrench tends to swing left and right from a predetermined value, making it difficult to accurately lock onto the predetermined torque.

The purpose of the present invention is to solve the above-mentioned drawbacks by making it possible to easily and reliably obtain a predetermined pressing force by simply rotating an operating lever corresponding to a torque wrench, and furthermore, when the predetermined pushing force is reached, the operating lever automatically It is an object of the present invention to provide a butt fusion machine in which the pressing force can be stably maintained at a predetermined value by providing a lock mechanism for preventing the operation of the button.

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.

FIG. 1 shows an outline of a butt fusion splicing machine for butt-welding (butt fusion splicing) the end faces of polyethylene pipes _P1 and _P2 as city gas conduits. In the figure, reference numeral 2 denotes a clamp for holding one of the pipes _P1 to be joined, and reference numeral 3 denotes a clamp (vice) for holding the other pipe _P2 . The clamps 2 and 3 are connected to a split ring 4.
One of the split rings, 4d, is formed integrally with the vise body, and the other ring, 4a, is pivotally attached thereto by a pivot pin (not shown) so that it can be expanded. The split rings 4a and 4d hold the pipes _P1 and _P2 , and the male thread portion 6 provided on one of the split rings, 4b,
The pipe is clamped by tightening the female screw 7 with a handle that is screwed into the ring 4a.
The female screw member 7 is pressed against a shoulder 14
In addition, the clamp ring 4a can be opened to the rear side (rear side of the drawing) by loosening the screw 7 and tilting it forward in FIG.

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

For example, a rectangular plate-shaped heater 20 is placed between the clamps 2 and 3 when necessary, and presses the joining end surfaces of the pipes P ₁ and P ₂ against the heater face of this heater, thereby heating and melting the end surfaces of the pipes P ₁ and P ₂ . do.

Incidentally, 50 is a chamfering machine for cutting the end surface of the tube to make it a uniform vertical flat surface before the tube is fused and joined.

The chamfering machine 50 is rotatably and slidably attached to one side of the bar 10 (the bar on the other side, not shown in FIG. 1), for example.

A handle 55 allows the chamfering machine 50 to take a chamfering position located between both clamps and a retracted position away from both clamps. Since the chamfering machine 50 itself has nothing to do with the present invention, further explanation will be omitted.

A pressurizing mechanism for pressing the movable clamp 3 toward the fixed clamp 2 has an operating lever 22 rotatably pivoted to the machine base 1 by a pin 25.
The pin 25 is rotatably supported by the machine base 1 and extends in a direction perpendicular to the pipe axis. Therefore pin 2
5 rotates together with lever 22. An identical link arm 27 is provided at the center of the pin 25 to face each other. These link arms 27 are relatively movably connected via pins 35 to a pusher 33 that is slidably fitted into a guide rod 31 extending from the center of the movable clamp 3 in the pipe axis direction (fifth
figure). That is, each arm 27 has a long hole 37 formed therein, into which the pin 35 of the presser 33 is fitted from both sides of the presser, so that when the arm 27 rotates together with the pin 25, the presser 33 is guided by the guide rod. 31 along this line. The guide rod 31 is inserted into a cylinder 41 which is fixed to the movable clamp 3. A thread 32 is formed at the tip of the guide rod 31, and is screwed into a female thread 42 formed at the inner periphery of the tip of the cylindrical body 41. The guide rod 31 may be immovably fixed to the movable clamp 3 or the cylinder 41, but the reason why the guide rod 31 is fixed to the cylinder 41 in such a manner that its relative position can be adjusted by screws (adjustment of initial load) will be described later. A portion (tip end) 33A of the presser 33 is slidably fitted into a cylinder 46 formed in the cylindrical body 41, and thus the tip end 33A forms a piston for the cylinder 46. An incompressible fluid 44 such as water or oil is housed within the cylinder 46 . Therefore, as described above, the rotation of the arm 27 is converted into a linear sliding movement of the presser 33 via the pin 35-elongated hole 37 mechanism, so that, for example, the lever 22, and therefore the arm 27, can be rotated clockwise in FIG. If the fluid 44 is
3 (piston) to apply a predetermined pressing force to the movable clamp 3. In addition, 4
8 is a return spring provided between the rod 31 and the presser 33.

The cylindrical body 41 is provided with detection means such as known pressure switches 61 and 63 for detecting a predetermined pressure of the fluid 44. In FIG. 3, pressure switches 61, 6
Two 3 are provided depending on the diameter of the pipe to be fused, but in carrying out the present invention, at least one is sufficient. That is, since the required crimp force is different if the pipe diameter is different, the illustrated embodiment is provided with two so that it can be applied to two types of pipes. If the pipe diameters are different, the inner diameters of the movable clamp 3 and the fixed clamp 2 are generally adjusted by inserting liners into the inner diameters of the movable clamp 3 and the fixed clamp 2. Therefore, the micro switch 65 is capable of detecting the presence or absence of this liner. For example, by providing a pressure switch 61 or 63 in the movable clamp 3, the detection signal can be used to control which of the pressure switches 61 and 63 should be used depending on the pipe diameter. These controls are carried out by a control unit 90 which is known per se. Detection signals from the pressure switches 61 and 63 are also input to the control unit 90, and a lock mechanism 70, which will be described later, is operated accordingly. In addition, 62, 64, 66
are the detectors of switches 61, 63, and 65, respectively.

The lock mechanism 70 has a housing 77 fixed to one side of the guide bar 10, and a slide rod 71 with peripheral teeth extending parallel to the guide bar 10 is slidably inserted into the housing (see Figs. 6 to 8). ). Block 7 is located at the tip of slide rod 71.
3 is fixed, and the operating lever 2 is attached to this block 73.
2 are relatively movably connected via a pin-elongated hole mechanism similar to the coupling mechanism between the link arm 27 and the presser 33. That is, a long hole 26 is formed in the lever 22, and a pin 81 fixed to the block 73 is inserted into the long hole 26. As a result, the rotational operation of the lever 22 is converted into a linear sliding movement of the slide rod 71 via the pin 81 and the elongated hole 26. Therefore, when the lock mechanism is not working, the slide rod 71 only moves following the operating lever 22 and does not interfere with the operation of the operating lever. Inside the housing 77 are outer teeth 72 of the slide rod 71.
A pair of half nuts 91A, 91B that can be engaged with
is provided. Half nuts 91A and 91B are 9
3A and 93B, it is always urged toward the lock position, that is, the engagement position with the slide rod 71. A cam 94 is provided between the half nuts 91A and 91B for pushing open the half nuts radially outward. As shown in FIG. 9, the cam 94 has its shaft portion 94A rotatably attached to the housing 77, and by rotating the cam 94, the half nuts 91A and 91B are pushed outward by the cam plate 94B. For example, a solenoid 97 is used as a means for rotating the cam 94. The swinging arm 96 is attached to the solenoid plunger 99 of the solenoid 97.
are relatively movably connected via the pin 103 and the elongated hole 101, and the shaft portion 94A of the cam 94 is integrally connected to the lower part of the swing arm 96. solenoid 9
7 is turned on, for example, by the main switch 108 at or prior to the start of the crimping operation, the plunger 99 projects to the imaginary position 99' in FIG. Rotate and half nut 91A, 9
1B is removed from the slide rod 71. In other words, the lock is released. Therefore, the operating lever 22 can be rotated. When the pusher 33 is advanced to a predetermined position by the operation lever 22 and the fluid 44 reaches a predetermined pressure, the pressure switch 61 (or 63) is turned on and the solenoid 97 is turned off in response to the signal, and as a result, the half nuts 91A and 91B are returned to the slide rod position. 71 and locks the slide rod 71. Therefore, the operating lever 2
2 can no longer move and is locked in place. In this way, according to the present invention, the pressing force by the pressing element 33 can be automatically maintained at a predetermined value.

It is necessary to adjust the initial pressure of the fluid 44 using the threaded portion 32 of the guide rod 31 described above in the following cases.

Butt welding of plastic pipes together, for example in the case of gas pipes or water pipes, often requires work at a buried site. On the other hand, recently, pipes have been wound in a spiral shape for ease of transportation, maintenance, and management. Of course, pipes wound in a spiral like this are used by being straightened out at the site, but it is impossible to straighten them out completely, so there is a U-shaped groove (earth hole) buried at the burial site. When a pipe is laid in the center), the pipe will be in a meandering state to some extent. That is, the pipe comes into contact with or is pressed against the side wall of the U-shaped groove at some point when viewed in the longitudinal direction. When the pipe is pulled in the longitudinal direction in this state, resistance is applied to the pipe due to friction between the pipe and the side wall of the U-shaped groove. That is, a resistance force against the tensile force acts. An initial load corresponding to this resistance force is applied to the pipe P ₂ and therefore the movable clamp 3 in advance, and no pressing force is applied via the presser 33 and the pressurized fluid 44 due to the operation of the lever 22. Avoid affecting it. In this way, the pipe _P2 can always be pressed against the heater or the pipe _P1 with a predetermined pressing force. Therefore, if no resistance force acts on the pipe _P1 , there is no need to consider the initial load. That is, there is no need to adjust the threaded portion 32 of the guide rod 31 relative to the threaded portion 42 of the housing 41.

As described above, according to the present invention, a predetermined pressing force can be easily and reliably obtained by simply rotating the operating lever 22, and when the predetermined pressing force is reached, it is automatically locked, and the pressing force remains at the predetermined value. Stably maintained.

[Brief explanation of drawings]

Figure 1 is an overall perspective view of the butt fusion machine according to the present invention, Figure 2 is a front view of the main parts of Figure 1, Figure 3 is a plan view of Figure 2, and Figure 4 is the same as Figure 3. Left side view, 5th
The figure is a main part view seen from the direction of arrow V in Figure 3, Figure 6 is a plan view showing the inside of the lock mechanism, and Figure 7 is a view of the lock mechanism.
8 is a sectional view taken along the line -- in FIG. 7, and FIG. 9 is a perspective view showing the cam. DESCRIPTION OF SYMBOLS 1...Machine base, 2...Fixed clamp, 3...Movable clamp, 10...Guide bar, 22...Operation lever, 31...Guide rod, 33...Press element, 4
4...fluid, 46... cylinder, 61, 63...
Pressure switch, 70...Lock mechanism.

Claims (1)

[Scope of utility model registration request] A fixed clamp on the machine that holds one resin pipe to be fused and a movable clamp that holds the other resin pipe are connected by a guide bar extending in a direction parallel to the pipe axis between the two clamps. The resin is equipped with a pressurizing mechanism that allows the movable clamp to approach and separate from the fixed clamp along a guide bar, and applies a predetermined pressing force to the movable clamp in order to press the molten joint surfaces of the resin pipes together with a predetermined pressing force. In the pipe butt fusion machine, the pressure mechanism includes an operating lever that is rotatably pivoted to the machine base, a presser that reciprocates in the tube axis direction in conjunction with the operating lever, and a presser that is coaxial with the presser. a guide member which is fixed to the movable clamp and slidably guides the presser, and a fluid which is located between the presser and the movable clamp and hydraulically transmits the pressing force from the presser to the movable clamp. 1. A butt welding machine for resin pipes, comprising a cylinder and a lock means for preventing operation of the operating lever in response to a signal from a detector for detecting a predetermined set pressure of the fluid.