JPS63417Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mold for processing the end of a synthetic resin pipe for forming a socket portion for fitting an elastic ring into the end of the synthetic resin pipe.

Socket part of earthquake-resistant bell pipe shown in Figure 1
When forming a socket part having a bulge part _Pa1 such as Pa on the end of the synthetic resin pipe P for fitting an elastic ring (not shown) from the inside, the guide 1, First type 2 and second type 3
A mold is used in which these are arranged in cascade.

The first type 2 has a structure in which an outer shell 21 and an inner shell 22 are arranged alternately surrounding a conical thruster 23 as shown in FIG. It has an outer surface and plate-shaped engagement legs 21a and 22a extending from their respective lower surfaces toward the axis of the thruster 23,
Slanted portions 21b, 22b of the engaging legs 21a, 22a
is the axially inclined guide groove 23 on the outer peripheral surface of the thruster 23.
a, 23b, and adjacent shells are connected by a tension spring (not shown). Furthermore, the second mold 3 of the outer shell 21 and the inner shell 22
Circumferential protrusions 21c and 22c are formed on the side end portions, and a stopper 21 is provided on the side end surface of the guide 1.
d, 22d are provided protrudingly. Thruster 23
is connected to rods 24, 24 of a reciprocating drive device such as a hydraulic cylinder (not shown), and is guided by a cup-shaped guide 1 and a guide shaft 4 whose both ends are fixed to a fixed part (not shown) and passes through the center of the mold. Driven back and forth.

This first type 2 moves the outer shell 21 and the inner shell 2 as the thruster 23 moves.
2 are guided by the guide surfaces of the guide grooves 23a and 23b, respectively, and move in the radial direction of the thruster 23, thereby contracting or expanding the diameter. At the time of maximum diameter expansion, that is, when the thruster 23 moves the maximum stroke in the direction of the arrow shown in the figure and the stoppers 21d and 22d engage with the inner circumferential surface of the guide 1 as shown in FIG. 1, the circular arcs of the circumferential projections 21c and 22c The outer surface continuously forms a circumferential surface as shown in FIG. 2B.

When processing the tube end, the diameter of the first mold 2 is reduced, and after fitting the preheated synthetic resin pipe P from the guide 1 side to the second mold 3, the first mold 2 is expanded as described above. After applying negative pressure to the vicinity of the circumferential protrusions 21c and 22c of the synthetic resin pipe P from the inside of the mold through holes (not shown) to form the bulge Pa ₁ , the first mold 2 is contracted. Synthetic resin pipe P
Pull out the tube end from the mold.

However, in this configuration, since the guide surfaces of the guide grooves 23a and 23b of the thruster 23 are single inclined surfaces, once the inclination angle θ ₂ of the guide surface of the guide groove 23b that engages with the engagement leg 22a of the inner shell 22 is determined. ,
Since the inclination angle θ ₁ (<θ ₂ ) of the guide surface of the guide groove 23a that engages with the engagement leg 21a of the outer shell 21 is automatically fixed, the degree of freedom in design is small, and it is difficult to use it for small diameter synthetic resin pipes. Indeed, it is difficult to set the inclination angle θ ₁ that allows stable operation to be performed smoothly while maintaining the desired relationship between the two shells. Since the length of the engagement surface with the surface is shortened, the outer shell 21 is tilted during tube end machining, resulting in a reduction in machining accuracy.

This invention was made to eliminate the above-mentioned conventional drawbacks, and the guide groove guide surface on the thruster that guides the engagement leg of the outer shell is inclined with respect to the axis of the thruster to move the outer shell to the maximum diameter expansion position. and a first guide surface parallel to the axis, and the engagement leg has a leg end shape corresponding to the guide groove guide surface, and the thruster guide To provide a mold for processing the end of a synthetic resin pipe, which makes the design of the groove easier than before and can safely eliminate tilting of the outer shell during processing.

An embodiment of the present invention will be described below with reference to the drawings.

In Figs. 3 and 4, 5 is a thruster, and like a conventional thruster 23, an outer shell 21 and an inner shell 22 are arranged around it.
are arranged alternately in a circle, but the outer shell 2
The guide surface of the guide groove 5a with which the first engaging leg 21e engages consists of a first guide surface _5a1 parallel to the axis and a second guide surface _5a2 continuous with the first guide surface and inclined at an inclination angle _θ3 toward the tip. The engaging leg 21e of the outer shell 21 has a horizontal slide end surface _21e1 extending from the circumferential projection 21c side end toward the opposite end,
The slide end surface is connected to the engagement end surface 21, which is inclined toward the tip end in parallel with the second guide surface 5a, i.e., has an inclination of an angle θ ₃ with respect to the axis of the thruster 5.
e ₂ is formed. 5b is the guide groove 23 in FIG.
The other configurations are the same as those in Fig. 1, so the same parts are given the same reference numerals.

In this configuration, when the thruster 5 is moved toward the guide 1 in the state shown in FIG. 4 in which the first mold 1 is in the minimum diameter contracted state, the inner shell 22
is pushed up and down in the figure by the guide surface of the guide groove 23b as in the conventional case. On the other hand, outer shell 2
1 is pushed down in the figure by the second guide surface 5a ₂ , and when the thruster 5 moves by a distance l ₁ , the slide end surface 21e ₁ engages with the first guide surface 5a ₁ and reaches the maximum diameter expansion position. , and thereafter the slide end surface 21e ₁ and the first guide surface 5a ₁ slide relative to each other without moving in the radial direction. When the thruster 5 moves by the maximum stroke l ₂ (>l ₁ ), the inner shell ₂₂ reaches the maximum diameter expansion position as shown in FIG.
comes into contact with the guide surface _5a2 . In this way, the second guide surface 5a ₂ functions to move the outer shell 21 in the radial direction of the thruster 5, and the first guide surface 5a ₁ functions to maintain the outer shell 21 at the maximum diameter expansion position. From, the inclination angle θ ₃ is the inclination angle θ ₂
The engagement leg 21e can be increased or decreased independently of the engagement leg 21e.
The length of the engaging surface that engages with the guide groove 5a is the length of the engaging leg 2.
The length of the engagement surface that engages with the guide groove 5b of 2a can be made longer.

As described above, according to the present invention, the guide groove on the thruster that guides the engagement leg of the outer shell is continuous with the second guide surface that has the function of moving the outer shell in the radial direction of the thruster. The inclination angle of the second guide surface is reduced by having a structure having a first guide surface that is formed as a cylindrical shape and has a function of holding the outer shell at the maximum diameter expansion position until the inner shell reaches the maximum diameter expansion position. of,
Since it can be set independently of the inclination angle of the guide groove that guides the inner shell, it is possible to easily design the guide grooves of the outer shell and inner shell, regardless of the diameter of the synthetic resin pipe to be processed. First, the length of the engagement surface between the outer shell and the thruster at the thruster's maximum stroke can be made much longer than before, completely eliminating the situation where the outer shell tilts when machining pipe ends. , which further increases machining accuracy.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of a conventional mold for processing the end of a synthetic resin pipe, and Fig. 2 A and B are half-sections showing the diameter-reduced state and diameter-expanded state of the first mold in the above-mentioned mold, respectively. 3 is a longitudinal sectional view of an embodiment of the pipe end processing mold according to the present invention, and FIG. 4 is a longitudinal sectional view of the main part showing the reduced diameter state of the first mold of the above embodiment. be. 1... Guide, 2... First mold, 3... Second mold, 4... Guide shaft, 5... Thruster, 5a...
Guide groove, 5a ₁ ... first guide surface, 5a ₂ ... second guide surface, 21 ... outer shell, 21c, 22
c... Circumferential projection, 21e, 22a... Engagement leg,
21e ₁ ... slide end surface, 21e ₂ ... engagement end surface,
22...Inner Ciel.

Claims (1)

[Scope of utility model registration request] Outer shells and inner shells having circumferential protrusions are alternately arranged around a conical thruster, and their respective engagement legs engage with axial guide grooves on the outer surface of the thruster, and when the thruster moves in the axial direction, In the pipe end processing mold, which includes a mold in which both shells move in a radial direction to contract and expand the diameter, the guide surface of the guide groove that is engaged by the engaging leg of the outer shell is aligned with the axis of the thruster. a first guide surface extending in the axial direction, and a second guide surface sloping toward the tip, and the engagement leg of the outer shell has a sliding end surface extending in the axial direction;
A mold for processing the end of a synthetic resin pipe, comprising an engaging end surface that is continuous with the slide end surface and slopes toward the tip in parallel with the second guide surface.