JP3330209B2 - Measurement method for torsion of oval plastic tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring the torsion of a plastic tube having an oval cross section in which a large-diameter arc and a small-diameter arc are connected by a gentle curve.

[0002]

2. Description of the Related Art Conventionally, plastic pipes having an oval cross section have been used for sewer pipes buried underground. As shown in FIG. 4, this oval-shaped plastic tube is formed by connecting a large-diameter arc R and a small-diameter arc r with a gentle curve to form an oval cross section, and burying the oval plastic tube in the ground. In this case, the large-diameter arc R is positioned upward, and the center line L1 (L2) connecting the center point O1 of the large-diameter arc R and the center point O2 of the small-diameter arc r is set to be vertical. Piping.

[0003]

However, the center line L1 at one end of the oval-shaped plastic tube may not coincide with the center line L2 at the other end of the tube due to twisting (see FIG. 4). 3), when the spigot 12 at the other end of the oval plastic tube 1 is inserted into the enlarged diameter receiving port 11 provided at one end of the oval plastic tube 1 as shown in FIG. , L2 did not match, and connection could not be established.

The twist of the egg-shaped plastic tube is caused by a manufacturing process. When a molten resin is extruded from a mouthpiece having an egg-shaped cross section to produce an egg-shaped plastic tube, the amount of extrusion and take-off are determined. When the speed fluctuated or the temperature distribution of the mouthpiece changed, it sometimes twisted after being extruded from the mouthpiece.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and has an object to provide a method for simply and surely measuring the torsion of an egg-shaped plastic pipe, with the object of ensuring that there is no variation in quality and that pipe connection can be reliably performed. Is what you do.

[0006]

According to the present invention, a centering device is mounted on both ends of a plastic pipe having an oval cross section in which a large-diameter arc and a small-diameter arc are connected by a gentle curve.
A transmitter and a receiver are mounted on support rods that stand along the center line of each centering tool. Therefore, a signal transmitted from the transmitter is received by the receiver, and the displacement of the center line connecting the center point of the large-diameter arc and the center point of the small-diameter arc at both ends of the plastic tube is measured.

[0007]

[Effect] A centering device is attached to both ends of an oval plastic tube, and a transmitter and a receiver are mounted on a support rod standing upright along the center line of each centering device, and a signal transmitted from the transmitter is transmitted. When received by the receiver, the displacement of the center line connecting the center point of the large-diameter arc and the center point of the small-diameter arc at both ends of the oval plastic tube can be measured.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a partial sectional front view showing one embodiment of the present invention,
FIG. 2 is an enlarged side view showing the end of the oval plastic tube, wherein reference numeral 1 denotes an oval plastic tube, 2 and 3 centering tools, 4 denotes a transmitter, 5 denotes a receiver, and 6 denotes a gantry. is there.

The egg-shaped plastic tube 1 is obtained by extruding a vinyl chloride resin or the like, and has a cross-sectional egg shape in which a large-diameter arc R and a small-diameter arc r are connected by a gentle curve. . One end of the egg-shaped plastic tube 1 cut into a fixed length is provided with an enlarged-diameter receiving port 11, and a spigot 12 at the other end of the expanded-diameter receiving port 11 is expanded and contracted via a rubber ring 13. It can be connected freely. A center line L1 connecting the center point O1 of the large-diameter arc R and the center point O2 of the small-diameter arc r is provided on the inner surfaces of the distal ends of the enlarged diameter receiving port 11 and the spigot 12.
, L2 are provided with depressions a, b for positioning the centering members 2, 3, respectively.

In the present invention, first, the egg-shaped plastic tube 1 is placed on the gantry 6, and the egg-shaped plastic tube 1 is set substantially horizontally. Next, the socket 1 of the oval plastic tube 1
1. Inserting the centering tools 2 and 3 into the spigot 12 and attaching the transmitter 4 and the receiver 5 to the supporting rods 21 and 31 standing along the center lines of the centering tools 2 and 3, respectively. The transmitter 4 is placed on the center lines L1 and L2 at both ends of the oval plastic tube 1.
And receiver 5 are positioned. Therefore, when the signal transmitted from the transmitter 4 is received by the receiver 5, the displacement of the center lines L1 and L2 connecting the center point O1 of the large-diameter arc and the center point O2 of the small-diameter arc at both ends of the plastic tube 1 is determined. Can be measured.

As the transmitter 4, a laser projector that emits a laser beam by using, for example, a semiconductor or a diode can be used. Further, as the receiver 5, a laser light receiver that can perform analog analysis after receiving the laser beam can be used, but other suitable transmitters and receivers can be used. In this embodiment, the transmitter 4 is provided on the receiving port 11 side.
Is set and the receiver 5 is set on the outlet 12 side. However, the same effect can be obtained by setting the transmitter 4 and the receiver 5 in the opposite positions. Further, the present invention can be applied to the case where the torsion of an oval plastic tube having no enlarged diameter receiving port 11 at one end is measured.

[0012]

As described in detail above, according to the present invention, the displacement of the center line connecting the center point of the large-diameter arc and the center point of the small-diameter arc at both ends of the oval plastic tube can be measured simply and reliably. Therefore, it is possible to provide an egg-shaped plastic pipe which has no variation in quality and can reliably perform pipe connection.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional front view showing one embodiment of the present invention.

FIG. 2 is an enlarged side view showing the end of an oval plastic tube.

FIG. 3 is a front view showing a connected state of an oval plastic tube.

FIG. 4 is a schematic diagram illustrating the twist of an oval plastic tube.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Oval plastic tube 2, 3 Centering tool 4 Transmitter 5 Receiver

Claims (1)

(57) [Claims] 1. A centering device (2), (3) is attached to both ends of a plastic tube (1) having an oval cross section in which a large-diameter arc and a small-diameter arc are connected by a gentle curve. A transmitter (4) and a receiver (5) are attached to a support rod standing upright along the center line of the centering tools (2) and (3), and a signal transmitted from the transmitter (4) is received by the receiver (5). ) To measure the displacement of the center lines (L1) and (L2) connecting the center point (O1) of the large-diameter arc and the center point (O2) of the small-diameter arc at both ends of the plastic pipe (1). A method for measuring the torsion of an oval plastic tube, characterized in that: