JPH0362954B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention serves to prevent pipe pulling resistance when connecting gas pipes or water pipes by mechanical connecting means without cutting threads. This invention relates to a stopper for pipe fittings.

[Prior art] Conventionally, for example, Japanese Patent Application Laid-Open No. 53-134225 has
2. Description of the Related Art As shown in FIGS. 3 and 3, there is a known pipe fitting retainer in which a plurality of rotatable recess members such as steel balls are arranged on the circumference of the joint and held by an elastic ring.

[Problems to be Solved by the Invention] This type of retaining tool is configured such that when the cap nut is screwed onto the joint body and tightened, the tapered surface formed on the inner surface of the cap nut is pressed, and the biting member is pressed against the outer peripheral surface of the pipe. While rotating between the pipe and the tapered surface, the pipe sinks deeply into the outer circumferential surface of the pipe and prevents the pipe from being pulled out after being connected. However, when connecting externally resin-coated steel pipes, which have become commonly used in recent years, when a cap nut is screwed into the joint body during connection and rotated to tighten, the steel ball-shaped biting member rotates around the pipe. Therefore, the resin layer of the outer resin-coated steel pipe is incised in a spiral manner. For this reason, it was not preferable in terms of corrosion protection of steel pipes.

Also, in terms of preventing the steel pipe from being pulled out, when a pulling force is applied to the steel pipe, the steel balls of the pull-out stopper rotate between the tapered surface and the outer circumferential surface of the pipe, so the pull-out length of the steel pipe is large, and the joint body If the insertion length of the steel pipe before connection is not ensured sufficiently, only a small pull-out prevention force will be obtained. For this reason, the shape of the joint body had to be made large, and it was difficult to obtain a large pull-out prevention force with a small pull-out length.

An object of the present invention is to provide a pipe joint removal stop that solves the above problems.

[Means for Solving the Problems] The gist of the present invention is that a plurality of biting members each having a spherical shape on the inner surface and a smooth outer surface are disposed intermittently in the circumferential direction, and the biting members are This is a retainer for pipe fittings, which is characterized by being connected and held in an annular manner by an elastic ring.

[Function] The contact surface of the biting member against the outer circumferential surface of the pipe is a sharp edge, so even when the nut is rotated, the biting member does not rotate around the tube on the outer circumferential surface of the tube, and the outer surface has a smooth spherical surface. Therefore, it slides on the tapered inner surface of the cap nut and bites deeply into the tube at a certain position on the outer circumferential surface of the tube. Therefore, the biting member does not cause any biting damage in places other than the biting part on the outer circumferential surface of the tube.

[Embodiment] FIG. 1 shows a typical embodiment of the present invention, in which A shows a partially sectional front view and B shows a side view. A pipe joint retainer 1 is made up of a plurality of recess members 2 arranged at equal intervals on the circumference and connected and held in an annular shape by a rubber band 3 so that the retainer 1 can be inserted into the outer periphery of a connecting pipe. An emotional blade part 21 is formed on the inner peripheral surface of this biting member 2, and the outer peripheral surface has a smooth spherical shape 22. The blade portion 21 may not be continuous but may be annular intermittently, or may be annular in a triangular or square shape instead of an arc as shown in the figure.

Next, the state in which the pipe joint removal prevention tool of the present invention is used in the pipe joint 1 will be explained with reference to FIGS. 4 to 6.

4 is the fitting body, and a cap nut 5 is attached to the male thread on the outer surface of the end.
are screwed together. A packing 6 having a wedge-shaped cross section is attached to the inner surface of the end portion of the joint body 4, and a retainer 7 is subsequently attached to the retainer 1. The outer peripheral surface of the biting member 2 of the stopper 1 is in contact with the tapered inner surface formed on the inner surface of the cap nut when the joint body 4 and the cap nut 5 are hand-tightened. Next, FIG. 5 shows a state in which the cap nut 5 is tightened with a pipe wrench or the like from the hand-tight state shown in FIG. 8 to seal the fluid flowing inside the embedding member 2.
The diameter of the outer peripheral surface of the tube 8 is reduced by the tapered surface 51 on the inner surface of the cap nut, and the cutting edge portion 21 formed on the inner surface of the biting member 2 is bitten into the outer surface of the tube 8. Even when the cap nut 5 is rotated by tightening, this biting member 2 slides between the tapered surface 51 because the outer peripheral surface of this biting member has a smooth spherical shape 22, and the inner surface of the biting member 2 Since it becomes an annular blade and is embedded in the outer peripheral surface of the tube 8, it does not roll against the outer surface of the tube and does not move at the same position as the initial insertion. Next, FIG. 6 shows a state in which a pulling force is applied to the tube 8 from the connected state shown in FIG. The biting member 2 is deeply wedged into the outer surface of the tube 8 and exhibits a stronger pulling-out prevention force.
The parallel portion 52 formed at the end of the small diameter side of the tapered surface 51 is for holding down the depth of biting of the biting member into the tube to a certain limit.
When the biting member 2 moves to 2, the progress of biting into the tube 8 is stopped. However, since the blade part 21 of the biting member of the present invention has an annular shape, it is easy to bite into the pipe, and since the biting member stably contacts and bites into the outer periphery of the pipe, the force of the blade part 21 to pull out the pipe is reduced. There will be no chipping or slipping on the outer circumferential surface of the tube.
According to experimental results, it is approximately 2 to 3 times faster than conventional steel ball recessed members under the same pipe and fitting conditions.
It showed double the pull-out strength.

FIGS. 7 and 8 show another experimental example of a pipe fitting using the pipe fitting stopper 1 of the present invention. As mentioned above, the stopper 1 of the present invention can be easily and stably attached to the outer circumferential surface of a pipe. Since it is strongly embedded, the length of insertion into the joint body can be shortened. Therefore, as shown in Fig. 7, it can be attached to the inner circumferential surface of the two-split housing member to prevent it from coming off the pipe due to the tightening force of the housing, and as shown in Fig. 8, it can be attached to the inner surface of the flange instead of a cap nut. It can also be used for flange-type pipe fittings with a tapered surface, so its range of applications is wide.

[Effects] As explained above, the pipe fitting retainer of the present invention is easily, stably, and strongly embedded into the outer circumferential surface of the pipe, so the force to prevent the pipe from being pulled out is far greater than that of conventional pipe fittings using steel balls. Moreover, since there is no movement of the biting part on the outer circumferential surface of the tube, there is no unnecessary biting damage on the outer circumferential surface of the tube, and furthermore, the length of the tube insertion into the joint body can be reduced. Therefore, the overall shape can be made compact, and it can also be used as a housing-type or flange-type insert member.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the present invention, in which A shows a partially sectional front view and B shows a side view. Fig. 2 is a perspective view showing a conventional pull-out stopper, Fig. 3 is a sectional view of an embodiment of a pipe joint using the conventional pull-out stopper, and Figs. 4 to 6 show pipe fittings using the pull-out stopper of the present invention. FIGS. 7 and 8 are partial sectional views showing another embodiment of a pipe joint using the retainer of the present invention. 1... Removal stopper for pipe joint, 2... Biting member, 3... Rubber band, 21... Blade, 22...
Spherical outer peripheral surface, 4... Joint body, 5... Cap nut, 51... Tapered inner surface, 8... Outer surface resin coated steel pipe.

Claims (1)

[Claims] 1. A plurality of biting members having an annular cutting edge on the inner surface and a smooth spherical surface on the outer surface are disposed intermittently in the circumferential direction, and the biting members are connected and held in an annular shape by an elastic ring. Removal stopper for pipe fittings.