Mould locking structure of internal expansion mould

Abstract

The utility model provides a mold locking structure of an internal expansion mold, and belongs to the technical field of machinery. The problem of how to reduce the rejection rate of pipe fittings is solved. According to the mold locking structure of the internal expansion mold, the internal expansion mold comprises a circular-tube-shaped shell, a rotating shaft rotationally connected into the shell and a push-pull rod connected with the rotating shaft through a lead screw nut pair; the fixed plate is in a long strip shape and is bent in the width direction to be in an arc shape, the movable plate is in a long strip shape and is bent in the width direction to be in an arc shape, and the movable plate is hinged to the push-pull rod through a hinge assembly. The mold locking structure comprises a ratchet wheel fixed outside the rotating shaft in the circumferential direction and a spring pin connected into the shell, and the spring pin is connected with the ratchet wheel in a clamped mode so that the rotating shaft can be limited in the circumferential direction. The mold locking structure of the internal expansion mold can effectively reduce the rejection rate of pipe fittings.

Description

Technical Field

[0001] The utility model belongs to the technical field of machinery and relates to a locking structure of an internal expansion mold. Background Art

[0002] The polyethylene winding structure wall tube is mainly made of polyethylene resin and is made of thermoplastic plastic pipe without internal pressure by winding molding process. It is generally manufactured by an internal expansion mold. The internal expansion mold generally includes a tubular outer shell and a driving device installed in the outer shell. Specifically, the outer shell includes two long fixed plates that are curved in an arc shape along the width direction and a long movable plate that is curved in an arc shape along the width direction. At the same time, the driving device includes a rotating shaft installed in the outer shell and capable of rotating in the circumferential direction, and a push-pull rod connected to the rotating shaft through a ball screw nut pair. A plurality of hinge seats are provided on the inner side surface of the movable plate along the length direction, and the push-pull rod is hinged to each hinge seat through a plurality of hinge shafts.

[0003] Before manufacturing, the worker first rotates the rotating shaft. At this time, the push-pull rod moves back to the rotating shaft, and pushes the articulated seats through the articulated shafts, so that the movable plate moves outward and cooperates with the two fixed plates to enclose the outer shell to make it round. At this time, the worker wraps the polyethylene sheet and liner around the outer shell, heats the outer shell and melts the two into one. After the formed pipe is cooled, the worker rotates the rotating shaft in the opposite direction. At this time, the push-pull rod moves in the opposite direction and pulls the articulated seats through the articulated shafts, so that the movable plate moves inward and separates from the fixed plate, thereby realizing the loosening deformation of the outer shell. At this time, the worker can take out the pipe outside the outer shell.

[0004] However, in actual operation, especially when the pipe fittings are in a cooling state, due to the principle of thermal expansion and contraction, the inner wall of the pipe fittings will continuously squeeze the movable plate, and there may be a phenomenon that the movable plate is squeezed inward by the pipe fittings, causing the outer shell of the pipe fittings to loosen and deform before it is completely cooled, which can easily cause the pipe fittings to deform and become scrapped. Summary of the invention

[0005] The purpose of the utility model is to solve the above problems in the prior art and propose a clamping structure of an internal expansion mold. The technical problem to be solved by the utility model is: how to reduce the scrap rate of pipe fittings.

[0006] The purpose of the utility model can be achieved through the following technical solutions: a locking structure of an internal expansion mold, the internal expansion mold includes a tubular outer shell, a rotating shaft rotatably connected to the outer shell, and a push-pull rod connected to the rotating shaft through a screw nut pair, the outer shell is surrounded by a fixed plate that is long and curved in an arc along the width direction and a movable plate that is long and curved in an arc along the width direction, the movable plate and the push-pull rod are hinged by a hinge assembly, and is characterized in that the locking structure includes a ratchet fixed to the outside of the rotating shaft along the circumferential direction and a spring pin connected to the outer shell, the spring pin is engaged with the ratchet so that the rotating shaft is circumferentially limited.

[0007] Compared with the prior art, the clamping structure of the present internal expansion mold is different in that, through the arrangement of the ratchet and the spring pin, when the movable plate moves outward and cooperates with the fixed plate to enclose the outer shell so that the outer shell is in a circular state, the spring pin engages with the teeth on the ratchet, so that the ratchet is locked in the circumferential direction, and because the ratchet is fixed outside the rotating shaft, the rotating shaft can be circumferentially limited under the cooperation of the ratchet and the spring pin, so that the movable plate is positioned at the current position and cannot move inward or outward. That is to say, during the cooling and forming process of the pipe fitting, although the inner wall of the pipe fitting expands and contracts due to heat The outer walls of the fixed plate and the movable plate are continuously squeezed, but since the rotating shaft is positioned, the screw nut pair, the push-pull rod and the movable plate are all in a fixed state, and the extrusion force of the pipe fitting is continuously transmitted to the clamping point of the ratchet and the spring pin through the above three, and this part of the extrusion force is unloaded through the cooperation of the ratchet and the spring pin, thereby preventing the movable plate from being squeezed inward during the cooling and shaping process of the pipe fitting, thereby preventing the outer shell from being deformed during the cooling and shaping of the pipe fitting, and further preventing the pipe fitting from being deformed accordingly due to the deformation of the outer shell, effectively reducing the scrap rate of the pipe fitting.

[0008] In the above-mentioned clamping structure of the internal expansion mold, a fixing seat in the form of an annulus and fixedly connected to the fixing plate is provided in the shell, and the rotating shaft and the screw nut pair are both passed through and connected to the fixing seat. The setting of the fixing seat can achieve the effect of circumferentially limiting the rotating shaft and the screw nut pair, so as to ensure that the two are stably installed. During operation, the rotating shaft and the screw nut pair can only perform circumferential rotation, and can also ensure that the push-pull rod connected to the screw nut pair is limited along the length direction of the shell, so that it can only move along the length direction of the shell.

[0009] In the above-mentioned clamping structure of the internal expansion mold, a mounting plate is fixed on the fixed seat, and the spring pin is arranged along the radial direction of the ratchet and connected to the mounting plate. The mounting plate is supported by the fixed seat to ensure the stable installation of the spring pin, and the spring pin is arranged along the radial direction of the ratchet to effectively ensure that the spring pin and the ratchet are fully matched.

[0010] In the above-mentioned clamping structure of the internal expansion mold, the mounting plate includes a fixing portion fixed to the fixing seat in the vertical direction and a mounting portion bent away from the push-pull rod, the mounting portion is located directly above the ratchet and a mounting hole is provided on the plate surface, and the spring pin is clamped in the mounting hole. Specifically, the mounting plate is fixedly connected to the fixing seat through the fixing portion, and the spring pin is carried by the mounting portion. The mounting portion is specifically bent away from the push-pull rod, so that the mounting portion is located directly above the ratchet, which can not only enable the spring pin to cooperate with the ratchet through the mounting hole to fully position the rotating shaft circumferentially, but also effectively protect the ratchet through the mounting portion.

[0011] In the above-mentioned clamping structure of the internal expansion mold, the front end of the rotating shaft is chamfered in the circumferential direction to form an external hexagonal shape, so that during operation, the worker can selectively screw the rotating shaft by a wrench or manually.

[0012] In the above-mentioned clamping structure of the internal expansion mold, the hinge assembly includes a plurality of hinge rods and a plurality of hinge seats arranged at intervals on the surface of the movable plate along the length direction of the movable plate, and the plurality of hinge rods are arranged at intervals along the length direction of the push-pull rod, and one end of each hinge rod is hinged to the push-pull rod, and the other end is correspondingly hinged to the hinge seat. When the push-pull rod is driven by the rotating shaft to move away from the rotating shaft, the two ends of each hinge rod rotate around the hinge to achieve the movable plate being pulled inwardly, and vice versa, the movable plate is pushed outwardly to reset, ensuring that the movable plate cooperates with the fixed plate to enclose the outer shell in a round tube shape.

[0013] Compared with the existing technology, the clamping structure of the internal expansion mold has the following advantages:

[0014] The ratchet wheel fixed on the rotating shaft is engaged with the spring pin fixed on the mounting plate to prevent the pipe in the cooling state from squeezing the movable plate and to prevent the movable plate from being pushed inward to cause deformation of the outer shell, thereby avoiding the defect of deformation of the pipe due to deformation of the outer shell and effectively reducing the scrap rate of the pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural schematic diagram of the clamping structure of the internal expansion mold.

[0016] Figure 2 It is a schematic diagram of the structure of the clamping structure of the internal expansion mold after the fixed plate is removed.

[0017] Figure 3 yes Figure 2 A partial enlarged view of point A in the middle.

[0018] Figure 4 It is a structural schematic diagram of the clamping structure of the internal expansion mold after the fixed plate is removed from another perspective.

[0019] Figure 5 It is a structural schematic diagram of the fixed plate.

[0020] In the figure, 1. housing; 11. fixing plate; 12. mounting plate; 13. spring pin; 14. fixing seat; 2. rotating shaft; 21. ratchet; 3. screw-nut pair; 4. push-pull rod; 5. hinge assembly; 51. hinge rod; 52. hinge seat; 6. mounting plate; 61. fixing part; 62. mounting part; 621. mounting hole. DETAILED DESCRIPTION

[0021] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.

[0022] like Figure 1 As shown in the clamping structure of the internal expansion mold, the internal expansion mold includes a cylindrical shell 1. Specifically, the shell 1 is surrounded by a long strip-shaped fixed plate 11 that is curved in the width direction and a long strip-shaped movable plate 12. As a further preferred embodiment, the number of the fixed plate 11 can be one, two or more than two. Figure 2-5 A ring-shaped fixing seat 14 is fixed in the housing 1. The fixing seat 14 is fixed by welding with the fixing block and the fixing plate 11 (not shown in the drawings of this case). The orientation of the fixing seat 14 is the same as that of the housing 1. The internal expansion mold also includes a rotating shaft 2, a screw nut pair 3 and a push-pull rod 4, wherein the front end of the rotating shaft 2 is chamfered in a hexagonal shape along the circumferential direction, so that the worker can screw the rotating shaft 2 with a wrench. The front end of the screw nut pair 3 and the rear end of the rotating shaft 2 are inserted into the fixing seat 14 and connected, and the front end of the push-pull rod 4 is connected to the rear end of the screw nut pair 3. The push-pull rod 4 is hinged to the movable plate 12 through a hinge assembly 5. The hinge assembly 5 includes a plurality of bar-shaped hinge rods 51 and a plurality of hinge seats 52 fixed on the inner side of the movable plate 12 at intervals along the length direction of the movable plate 12. The plurality of hinge rods 51 and the plurality of hinge seats 52 are arranged in groups of two. The push-pull rod 4 is rotatably connected to a plurality of rotating shafts 1 arranged at intervals along the length direction of the push-pull rod 4. A rotating shaft 2 is rotatably connected between two hinge seats 52 in the same group. One end of the two hinge rods 51 in the same group is rotatably connected to the rotating shaft 1, and the other end is rotatably connected to the rotating shaft 2.

[0023] When the worker rotates the rotating shaft 2, under the limiting action of the fixed seat 14, the rotating shaft 2 can only make circumferential rotational motion, and drive the screw nut pair 3 to rotate, and at the same time the screw nut pair 3 drives the push-pull rod 4 to perform telescopic action. Specifically, the rotating shaft 2 rotates counterclockwise, and the push-pull rod 4 is driven to move away from the rotating shaft 2 through the screw nut pair 3. At this time, the push-pull rod 4 drives the movable plate 12 inward through the hinge assembly 5, even if the outer shell 1 is deformed to realize the demoulding of the pipe fitting. On the contrary, when the rotating shaft 2 rotates clockwise, the push-pull rod 4 is driven to move toward the rotating shaft 2 through the screw nut pair 3. At this time, the push-pull rod 4 drives the movable plate 12 outward through the hinge assembly 5, thereby making the outer shell 1 round.

[0024] The locking structure includes a ratchet 21 and a spring pin 13. The ratchet 21 is sleeved on the outside of the rotating shaft 2 and locked by screws. The fixed seat 14 is provided with a mounting plate 6. The mounting plate 6 includes a fixing portion 61 arranged vertically and integrally formed with the outer wall of the fixed seat 14 and a mounting plate 6 bent away from the push-pull rod 4. The mounting portion 62 is located directly above the ratchet 21 and a mounting hole 621 is opened on the plate surface. The spring pin 13 is fixed to the mounting portion 62 by snapping or screwing, so that the spring pin 13 passes through the mounting hole 621 and is snapped to the teeth on the ratchet 21 along the radial direction of the ratchet 21. As an alternative, the ratchet 21 can also be replaced with a positioning sleeve with a rough anti-slip surface on the circumferential outer wall and a bolt screwed into the mounting hole 621.

[0025] On the basis of the above structure, when the worker is debugging the position of the movable plate 12 through the rotating shaft 2, since several teeth on the circumferential outer wall of the ratchet 21 are bevel teeth, the ratchet 21 will not be delayed in rotation due to the presence of the spring pin 13 when the rotating shaft 2 rotates clockwise to push the movable plate 12 outward. On the contrary, when the rotating shaft 2 rotates counterclockwise, the ratchet 21 can be locked due to the locking cooperation between the spring pin 13 and the teeth, thereby preventing the movable plate 12 from being squeezed and moved inward. In addition, when demolding is required, it is only necessary to lift the spring pin 13 upwards before rotating the rotating shaft 2 counterclockwise to separate the spring pin 13 from the ratchet 21.

[0026] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

[0027] Although the present invention uses more terms such as housing 1, fixing plate 11, mounting plate 12, spring pin 13, fixing seat 14, rotating shaft 2, ratchet 21, screw nut pair 3, push-pull rod 4, hinge assembly 5, hinge rod 51, hinge seat 52, mounting plate 6, fixing portion 61, mounting portion 62, mounting hole 621, etc., it does not exclude the possibility of using other terms. The use of these terms is only for more convenient description and explanation of the essence of the utility model; interpreting them as any additional restrictions is contrary to the spirit of the utility model.

Claims

1. A clamping structure for an internal expansion mold, the internal expansion mold comprising a tubular outer shell (1), a rotating shaft (2) rotatably connected in the outer shell (1), and a push-pull rod (4) connected to the rotating shaft (2) through a screw nut pair (3), the outer shell (1) is surrounded by a fixed plate (11) which is long and curved in an arc shape along the width direction, and a movable plate (12) which is long and curved in an arc shape along the width direction, the movable plate (12) is hinged to the push-pull rod (4) through a hinge assembly (5), characterized in that: The mold locking structure comprises a ratchet (21) fixed circumferentially outside the rotating shaft (2) and a spring pin (13) connected to the housing (1); the spring pin (13) is engaged with the ratchet (21) so that the rotating shaft (2) is circumferentially limited.

2. The clamping structure of the bulging mold according to claim 1 is characterized in that: A ring-shaped fixing seat (14) is provided in the housing (1) and is fixedly connected to the fixing plate (11); the rotating shaft (2) and the screw nut pair (3) are both passed through the fixing seat (14) and are connected to each other.

3. The clamping structure of the internal expansion mold according to claim 2 is characterized in that: A mounting plate (6) is fixedly arranged on the fixing seat (14), and the spring pin (13) is radially arranged along the ratchet (21) and connected to the mounting plate (6).

4. The clamping structure of the internal expansion mold according to claim 3 is characterized in that: The mounting plate (6) comprises a fixing portion (61) fixed vertically on the fixing seat (14) and a mounting portion (62) bent away from the push-pull rod (4); the mounting portion (62) is located directly above the ratchet (21) and a mounting hole (621) is provided on the plate surface; the spring pin (13) is clamped in the mounting hole (621).

5. The clamping structure of the bulging mold according to any one of claims 1 to 4, characterized in that: The front end of the rotating shaft (2) is chamfered in the circumferential direction to form an external hexagonal shape.

6. The clamping structure of the bulging mold according to claim 5 is characterized in that: The hinge assembly (5) comprises a plurality of hinge rods (51) and a plurality of hinge seats (52) arranged on the surface of the movable plate (12) at intervals along the length direction of the movable plate (12); the plurality of hinge rods (51) are arranged at intervals along the length direction of the push-pull rod (4); one end of each hinge rod (51) is hinged to the push-pull rod (4), and the other end is correspondingly hinged to the hinge seat (52).

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