CN220198427U - Arc-shaped buckling position demoulding mechanism and mould - Google Patents

Abstract

The embodiment of the utility model discloses an arc buckling position demoulding mechanism and a mould, wherein the arc buckling position demoulding mechanism comprises a movable mould body, a fixed mould body, a mould core, an insert and a drawing component, wherein the mould core is arranged on the movable mould body, the mould core and the fixed mould body are enclosed to form a cavity, the drawing component comprises a sliding block seat, a sliding block, a swinging rod and a pull rod, the sliding block seat is connected with the movable mould body, the sliding block is in sliding fit with the sliding block seat and is connected with the insert, the swinging rod is rotationally connected with the movable mould body and is connected with the sliding block, the pull rod is connected with the fixed mould body, the swinging rod can drive the swinging rod to rotate relative to the sliding block seat in the mould opening process of the movable mould body, and the swinging rod can drive the sliding block and the insert to move in an arc mode to be far away from a product so as to draw the insert out from a back-off part of the product, the insert in demoulding can not damage the back-off, and the processing cost of the product is reduced on the premise of meeting the arc movement.

Description

Arc-shaped buckling position demoulding mechanism and mould

Technical Field

The utility model relates to the technical field of dies, in particular to an arc buckling position demolding mechanism and a die.

Background

In the process of injection molding products, some products have back-ups, so that the insert needs to be kept away from the back-ups of the products in advance before the mold is opened, and therefore back-ups are prevented from being damaged. When the existing insert is far away from the back-off, the rack is used as a transmission part, the rack is connected with the gear in a transmission mode, and the gear drives the insert to do circular arc motion to separate from the back-off.

Disclosure of Invention

Based on this, it is necessary to provide an arc knot position demoulding mechanism and mould, aims at solving the technical problem that the processing cost of the existing mold insert is higher when keeping away from the back-off, uses the rack as the drive part, and the rack is connected with gear drive, and the gear drives the mold insert again and makes circular arc motion and breaks away from the back-off to lead to the processing cost of product higher.

In a first aspect, the utility model provides an arc buckling position demolding mechanism, which comprises a movable die body, a fixed die body, a die core, an insert and a drawing component, wherein the die core is arranged on the movable die body, the die core and the fixed die body are enclosed to form a cavity, the cavity is used for molding a product, and the insert is used for being matched with a cavity wall of the cavity to mold an inverted buckle part of the product;

the drawing assembly comprises a sliding block seat, a sliding block, a swinging rod and a pull rod, wherein the sliding block seat is connected with the movable die body, the sliding block is in sliding fit with the sliding block seat and is connected with the insert, the swinging rod is in rotary connection with the movable die body and is connected with the sliding block, and the pull rod is connected with the fixed die body;

in the process of opening the die of the movable die body and the fixed die body, the pull rod can drive the swing rod to rotate relative to the slide block seat, and the swing rod can drive the slide block and the insert to move in an arc mode to be far away from the product so as to draw out the insert from the back-off part of the product.

In one embodiment, the pull rod is provided with a driving groove, the swing rod comprises a first rod body and a second rod body connected with the first rod body, the first rod body and the second rod body are arranged in an included angle, the connection part of the first rod body and the second rod body is rotationally connected with the movable mould body, and the end part of the second rod body is rotationally connected with the sliding block;

in the process of opening the die of the movable die body and the fixed die body, the groove wall of the driving groove can be abutted to the end part of the first rod body, so that the first rod body rotates under the limit of the groove wall of the driving groove, and the first rod body rotates to drive the end part of the second rod body, the sliding block and the insert to move in an arc mode so as to be far away from the product.

In one embodiment, in the process of closing the mold body and the fixed mold body, the groove wall of the driving groove can be abutted against the end part of the first rod body, so that the first rod body resets and rotates under the limitation of the groove wall of the driving groove, and the first rod body rotates to drive the end part of the second rod body, the sliding block and the insert to move in an arc mode so as to be inserted into the cavity.

In one embodiment, the groove wall of the driving groove is formed with a first driving surface, a stroke space and a second driving surface, wherein the stroke space has a first position and a second position;

in the process of opening the movable die body and the fixed die body, the end part of the first rod body moves from the first position to the second position, and the first driving surface is abutted with the end part of the first rod body at the second position so that the first rod body rotates under the driving of the first driving surface;

in the process of closing the die of the movable die body and the fixed die body, the end part of the first rod body moves from the second position to the first position, and the second driving surface is abutted to the end part of the first rod body at the first position so that the first rod body rotates under the driving of the second driving surface.

In one embodiment, the insert includes a mounting portion and a molding portion connected to the mounting portion, the molding portion being a bar having an arc.

In one embodiment, the drawing component further comprises a pressing block, the pressing block is provided with an arc-shaped groove, the surface of the sliding block seat is arc-shaped, the sliding block seat is connected with the groove wall of the arc-shaped groove and surrounds the groove wall of the arc-shaped groove to form a guide groove, and the sliding block is provided with a guide block which is slidably arranged in the guide groove.

In one embodiment, the arc-shaped buckling position demolding mechanism further comprises a first limiting piece, wherein the first limiting piece is installed on the fixed mold body and can abut against the sliding block, so that the insert can keep a mold closing position.

In one embodiment, the arc-shaped buckling position demolding mechanism further comprises a wear-resistant block, wherein the wear-resistant block is installed on one side, close to the first limiting piece, of the sliding block and is used for protecting the first limiting piece and the sliding block.

In one embodiment, the arc-shaped buckling position demolding mechanism further comprises a base, a second limiting piece and a power element, wherein the second limiting piece is in sliding connection with the base, the power element is connected with the second limiting piece and is used for driving the second limiting piece to move relative to the base so that the second limiting piece can prop against the first limiting piece; and/or

The sliding block seat is provided with an avoidance groove, and the avoidance groove is used for avoiding the second limiting piece.

In a second aspect, the present utility model further provides a mold, where the mold includes the arc-shaped buckling position demolding mechanism of any one of the embodiments.

The implementation of the embodiment of the utility model has the following beneficial effects:

by adopting the arc buckling position demoulding mechanism and the mould, the mould core of the arc buckling position demoulding mechanism is arranged on the movable mould body, the mould core and the fixed mould body are enclosed to form the mould cavity, the mould cavity is used for forming a product, the product can be injection molded into a preset shape, the insert is used for matching with the cavity wall of the mould cavity to form the back-off part of the product, the slide block seat is connected with the movable mould body, the slide block is in sliding fit with the slide block seat and is connected with the insert, the swing rod is rotationally connected with the movable mould body and is connected with the slide block, the pull rod is connected with the fixed mould body, the swing rod can drive the swing rod to rotate relative to the slide block seat in the mould opening process of the movable mould body, and the swing rod can drive the slide block and the insert to move arcuately away from the product, so that the insert in the demoulding can not damage the back-off part, and the swing rod and the pull rod are arranged to replace the rack and pinion transmission structure in the prior art to drive the arcuately move of the insert.

Drawings

In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the utility model, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Wherein:

FIG. 1 is an isometric view of an arcuate snap release mechanism in one embodiment.

Fig. 2 is an exploded view of the arc-shaped buckle-position demoulding mechanism shown in fig. 1.

Fig. 3 is an enlarged partial schematic view of the portion a of the arc-shaped buckle portion stripping mechanism shown in fig. 2.

Fig. 4 is an enlarged partial schematic view of the portion B of the arcuate buckle stripper mechanism of fig. 2.

Reference numerals:

1. a mold core; 2. an insert; 21. a mounting part; 22. a molding part;

3. a pull assembly; 31. a slider seat; 311. an avoidance groove; 32. a slide block; 321. a guide block; 33. swing rod; 331. a first rod body; 332. a second rod body; 34. a pull rod; 341. a driving groove; 3411. a first driving surface; 3412. a travel space; 34121. a first position; 34122. a second position; 3413. a second driving surface; 35. briquetting; 351. an arc-shaped groove; 36. a connecting shaft; 37. a rotating shaft;

4. a first limiting member; 5. a wear block; 6. a base; 7. a second limiting piece; 8. a guide member;

100. and (5) a product.

Detailed Description

The following description of the embodiments of the present utility model will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.

In the description of the present utility model, it should be noted that, if the terms "upper", "lower", "inner", "outer", and the like indicate an azimuth or a positional relationship based on the azimuth or the positional relationship shown in the drawings, or the azimuth or the positional relationship in which the inventive product is conventionally put in use, it is merely for convenience of describing the present utility model and simplifying the description, and it is not indicated or implied that the apparatus or element referred to must have a specific azimuth, be configured and operated in a specific azimuth, and thus it should not be construed as limiting the present utility model.

Furthermore, the terms "first," "second," and the like, if any, are used merely for distinguishing between descriptions and not for indicating or implying a relative importance.

It should be noted that the features of the embodiments of the present utility model may be combined with each other without conflict.

Referring to fig. 1 to 4 together, the arc-shaped buckling position demolding mechanism provided by the utility model is used in a mold. The arc buckling position demoulding mechanism comprises a movable mould body (not shown in the figure), a fixed mould body (not shown in the figure), a mould core 1, an insert 2 and a drawing component 3, wherein the mould core 1 is arranged on the movable mould body, the mould core 1 and the fixed mould body enclose to form a cavity, the cavity is used for forming a product 100, and the insert 2 is used for matching with a cavity wall of the cavity to form a back-off part of the product 100.

In this embodiment, the drawing assembly 3 includes a slide block seat 31, a slide block 32, a swing link 33 and a pull rod 34, the slide block seat 31 is connected with the movable mold body, the slide block 32 is in sliding fit with the slide block seat 31 and connected with the insert 2, the swing link 33 is rotationally connected with the movable mold body and connected with the slide block 32, and the pull rod 34 is connected with the fixed mold body.

In the process of opening the movable die body and the fixed die body, the pull rod 34 can drive the swinging rod 33 to rotate relative to the sliding block seat 31, and the swinging rod 33 can drive the sliding block 32 and the insert 2 to move in an arc shape to be far away from the product 100 so as to draw out the insert 2 from the back-off part of the product 100.

It can be appreciated that the mold core 1 of the arc buckling position demolding mechanism is mounted on the movable mold body, the mold core 1 and the fixed mold body are enclosed to form a cavity, the cavity is used for molding a product 100, the product 100 can be molded into a preset shape, the insert 2 is used for matching with the cavity wall of the cavity to mold the back-off part of the product 100, the slide block seat 31 is connected with the movable mold body, the slide block 32 is slidably matched with the slide block seat 31 and is connected with the insert 2, the swing rod 33 is rotationally connected with the movable mold body and is connected with the slide block 32, the pull rod 34 is connected with the fixed mold body, the swing rod 33 can be driven to rotate relative to the slide block seat 31 in the process of opening the movable mold body and the fixed mold body, the swing rod 33 can be driven to move in an arc mode to be far away from the product 100, so that the insert 2 can be pulled out from the back-off part of the product 100, the back-off can not be damaged in demolding, the swing rod 33 and the pull rod 34 are arranged to replace the arc-shaped movement of the rack gear transmission structure driving member 2 in the prior art, so that the processing precision and the production cost can be reduced.

Further, the pull rod 34 is provided with a driving slot 341, the swing rod 33 comprises a first rod body 331 and a second rod body 332 connected with the first rod body 331, the first rod body 331 and the second rod body 332 are arranged in an included angle, the connection part of the first rod body 331 and the second rod body 332 is rotationally connected with the movable die body, and the end part of the second rod body 332 is rotationally connected with the sliding block 32. Specifically, the included angles of the first rod 331 and the second rod 332 may be 30 degrees, 35 degrees, and 40 degrees. In practice, the degrees of the included angles between the first rod 331 and the second rod 332 can be set to be corresponding angles according to the contact between the wall of the driving slot 341 and the first rod 331.

Further, in the process of opening the movable mold body and the fixed mold body, the groove wall of the driving groove 341 can be abutted against the end portion of the first rod body 331, so that the first rod body 331 rotates under the limitation of the groove wall of the driving groove 341, and the first rod body 331 rotates to drive the end portion of the second rod body 332, the sliding block 32 and the insert 2 to move in an arc manner so as to be far away from the product 100.

Specifically, in the process of opening the movable mold body and the fixed mold body, the pull rod 34 and the swing rod 33 are moved away from each other, so that the groove wall of the driving groove 341 is abutted against the first rod body 331, the first rod body 331 can rotate under the action of the groove wall of the driving groove 341, the first rod body 331 drives the second rod body 332 to rotate relative to the slide block seat 31, the second rod body 332 drives the slide block 32 and the insert 2 to move in an arc manner, the insert 2 can be far away from the back-off of the product 100, and therefore the insert 2 cannot damage the back-off during mold opening.

Further, in the process of closing the moving mold body and the fixed mold body, the groove wall of the driving groove 341 can be abutted against the end portion of the first rod body 331, so that the first rod body 331 is reset and rotated under the limitation of the groove wall of the driving groove 341, and the end portion of the second rod body 332, the sliding block 32 and the insert 2 can be driven to move in an arc shape by the rotation of the first rod body 331 so as to be inserted into the cavity.

Specifically, in the process of die assembly of the movable die body and the fixed die body, the pull rod 34 and the swing rod 33 move close to each other, so that the groove wall of the driving groove 341 is abutted against the first rod body 331, the first rod body 331 can reset and rotate under the action of the groove wall of the driving groove 341, the first rod body 331 drives the second rod body 332 to reset and rotate relative to the sliding block seat 31, the second rod body 332 drives the sliding block 32 and the insert 2 to reset and move in an arc shape, and the insert 2 can be inserted into the cavity, so that the insert 2 can be matched with the cavity wall of the cavity to form the back-off part of the product 100 during die assembly.

It should be added that the drawing assembly 3 further includes a connecting shaft 36 and a rotating shaft 37, the end of the second rod 332 is rotatably connected to the slider 32 through the connecting shaft 36, and the connection part of the first rod 331 and the second rod 332 is rotatably connected to the movable mold body through the rotating shaft 37.

In one embodiment, as shown in fig. 2 to 3, the wall of the driving groove 341 is formed with a first driving surface 3411, a travel space 3412, and a second driving surface 3413, and the travel space 3412 has a first position 34121 and a second position 34122.

In the present embodiment, during the process of opening the movable mold body and the fixed mold body, the end portion of the first rod 331 moves from the first position 34121 to the second position 34122, and the first driving surface 3411 abuts against the end portion of the first rod 331 at the second position 34122, so that the first rod 331 is driven to rotate by the first driving surface 3411. Specifically, in the process that the end of the first rod 331 moves from the first position 34121 to the second position 34122, the moving die body is away from the fixed die body for a certain distance, so that other parts of the moving die body are prevented from interfering with the fixed die body, after a certain distance of movement, at the second position 34122, the first driving surface 3411 abuts against the end of the first rod 331, so that the first rod 331 rotates under the driving of the first driving surface 3411, the first rod 331 drives the second rod 332 to rotate, and the second rod 332 drives the sliding block 32 and the insert 2 to move in an arc shape, so that the insert 2 can be away from the back-off of the product 100, and the insert 2 cannot damage the back-off during die opening.

Further, during the process of clamping the movable mold body and the fixed mold body, the end portion of the first rod 331 moves from the second position 34122 to the first position 34121, and at the first position 34121, the second driving surface 3413 abuts against the end portion of the first rod 331, so that the first rod 331 rotates under the driving of the second driving surface 3413. Specifically, in the process that the end portion of the first rod 331 moves from the second position 34122 to the first position 34121, the movable mold body and the fixed mold body are close to each other, after a distance between the movable mold body and the fixed mold body is kept close to each other, at the first position 34121, the second driving surface 3413 abuts against the end portion of the first rod 331, so that the first rod 331 rotates under the driving of the second driving surface 3413, the first rod 331 drives the second rod 332 to reset and rotate, and the second rod 332 drives the slider 32 and the insert 2 to reset and move in an arc manner, so that the insert 2 can be close to the cavity, and the insert 2 can be matched with the cavity wall of the cavity to form the inverted buckle portion of the product 100 during mold closing.

In one embodiment, as shown in fig. 2, the insert 2 includes a mounting portion 21, and a molding portion 22 connected to the mounting portion 21, and the molding portion 22 is a bar having an arc. Since the molding portion 22 is a bar-shaped rod having an arc, the insert 2 needs to move in an arc so that the insert 2 can be far away from the product 100, so that the insert 2 does not damage the back-off of the product 100.

In an embodiment, as further shown in fig. 2, the drawing component 3 further includes a pressing block 35, the pressing block 35 is provided with an arc-shaped groove 351, the surface of the sliding block seat 31 is arc-shaped, the sliding block seat 31 is connected with the groove wall of the arc-shaped groove 351 and encloses with the groove wall of the arc-shaped groove 351 to form a guiding groove, the sliding block 32 is provided with a guiding block 321, and the guiding block 321 is slidably arranged in the guiding groove. Specifically, in the process of the arc movement of the slider 32 in the slider seat 31, the slider 32 can drive the guide block 321 to move along the guide groove, so that the slider 32 can move in a more stable arc shape. In addition, the slider 32 slides on the surface of the slider seat 31 during the arcuate movement, so that the slider seat 31 can receive the slider 32.

In an embodiment, as further shown in fig. 2, the arc-shaped buckling position demolding mechanism further includes a first limiting piece 4, the first limiting piece 4 is mounted on the fixed mold body, and the first limiting piece 4 can abut against the sliding block 32, so that the mold insert 2 can maintain the mold closing position.

Specifically, the first limiting member 4 abuts against the sliding block 32, so that the sliding block 32 can be kept at the die-closing position, the insert 2 cannot shake in the cavity, and the yield of the molded product 100 formed by matching the insert 2 with the cavity wall of the cavity is higher.

In this embodiment, the arc-shaped buckling position demolding mechanism further comprises a wear-resistant block 5, and the wear-resistant block 5 is mounted on one side of the sliding block 32, which is close to the first limiting piece 4, and is used for protecting the first limiting piece 4 and the sliding block 32. Because in the die opening or closing process, the first limiting piece 4 is required to be far away from the sliding block 32 and close to the sliding block 32, and wear between the first limiting piece 4 and the sliding block 32 is reduced by arranging the wear-resisting block 5, so that the service lives of the first limiting piece 4 and the sliding block 32 are prolonged.

In an embodiment, as shown in fig. 1 and 2, the arc-shaped buckling demolding mechanism further includes a base 6, a second limiting member 7, and a power element (not shown in the drawings), wherein the second limiting member 7 is slidably connected with the base 6, and the power element is connected with the second limiting member 7 and is used for driving the second limiting member 7 to move relative to the base 6, so that the second limiting member 7 can abut against the first limiting member 4. Through setting up second locating part 7, second locating part 7 butt first locating part 4 for slider 32 can more firm keep in current position, thereby make insert 2 can more firm keep in current position.

In this embodiment, the slide seat 31 is provided with an avoidance groove 311, and the avoidance groove 311 is used for avoiding the second limiting member 7. In this way, when the second limiting member 7 abuts against the first limiting member 4, the second limiting member 7 does not interfere with the slider seat 31.

Further, the arc-shaped buckling position demoulding mechanism further comprises a guide piece 8, wherein the guide piece 8 is arranged in the seat body 6 and used for guiding the second limiting piece 7.

The utility model also provides a die, which comprises the arc buckling position demoulding mechanism of any embodiment.

It will be appreciated that the mold in this embodiment uses the above-described arc-shaped buckling-position demolding mechanism, and the arrangement of the swing rod 33 and the pull rod 34 replaces the prior art rack-and-pinion driving structure to drive the arc-shaped movement of the insert 2, so that the machining precision and cost can be reduced, and the production cost can be reduced.

It is to be added that the mold further comprises a movable mold and a fixed mold, wherein the movable mold comprises a movable mold body, a mold core 1, an insert 2, a slide block seat 31, a slide block 32 and a swing rod 33, and the fixed mold comprises a fixed mold body and a pull rod 34.

The mold is used for manufacturing a car lamp lens.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The foregoing disclosure is illustrative of the present utility model and is not to be construed as limiting the scope of the utility model, which is defined by the appended claims.

Claims (10)

1. The arc buckling position demoulding mechanism is characterized by comprising a movable mould body, a fixed mould body, a mould core, an insert and a drawing component, wherein the mould core is arranged on the movable mould body, the mould core and the fixed mould body are enclosed to form a cavity, the cavity is used for forming a product, and the insert is used for being matched with a cavity wall of the cavity to form an inverted buckle part of the product;

the drawing assembly comprises a sliding block seat, a sliding block, a swinging rod and a pull rod, wherein the sliding block seat is connected with the movable die body, the sliding block is in sliding fit with the sliding block seat and is connected with the insert, the swinging rod is in rotary connection with the movable die body and is connected with the sliding block, and the pull rod is connected with the fixed die body;

in the process of opening the die of the movable die body and the fixed die body, the pull rod can drive the swing rod to rotate relative to the slide block seat, and the swing rod can drive the slide block and the insert to move in an arc mode to be far away from the product so as to draw out the insert from the back-off part of the product.

2. The arc buckling position demoulding mechanism according to claim 1, wherein the pull rod is provided with a driving groove, the swing rod comprises a first rod body and a second rod body connected with the first rod body, the first rod body and the second rod body are arranged in an included angle, the joint of the first rod body and the second rod body is rotationally connected with the movable mould body, and the end part of the second rod body is rotationally connected with the sliding block;

in the process of opening the die of the movable die body and the fixed die body, the groove wall of the driving groove can be abutted to the end part of the first rod body, so that the first rod body rotates under the limit of the groove wall of the driving groove, and the first rod body rotates to drive the end part of the second rod body, the sliding block and the insert to move in an arc mode so as to be far away from the product.

3. The arc buckling position demolding mechanism according to claim 2, wherein in the process of clamping the movable mold body and the fixed mold body, the groove wall of the driving groove can be abutted against the end part of the first rod body, so that the first rod body can reset and rotate under the limit of the groove wall of the driving groove, and the end part of the second rod body, the sliding block and the insert can be driven to move in an arc mode by the rotation of the first rod body so as to be inserted into the cavity.

4. The arc button demolding mechanism of claim 3, wherein a groove wall of the driving groove is formed with a first driving surface, a stroke space and a second driving surface, the stroke space having a first position and a second position;

in the process of opening the movable die body and the fixed die body, the end part of the first rod body moves from the first position to the second position, and the first driving surface is abutted with the end part of the first rod body at the second position so that the first rod body rotates under the driving of the first driving surface;

in the process of closing the die of the movable die body and the fixed die body, the end part of the first rod body moves from the second position to the first position, and the second driving surface is abutted to the end part of the first rod body at the first position so that the first rod body rotates under the driving of the second driving surface.

5. The arcuate buckle position demoulding mechanism of claim 1, wherein the insert comprises a mounting portion and a forming portion connected with the mounting portion, the forming portion being a bar having an arc.

6. The arc buckling position demolding mechanism according to claim 1, wherein the drawing assembly further comprises a pressing block, the pressing block is provided with an arc-shaped groove, the surface of the sliding block seat is arc-shaped, the sliding block seat is connected with the groove wall of the arc-shaped groove and surrounds the groove wall of the arc-shaped groove to form a guide groove, the sliding block is provided with a guide block, and the guide block is slidably arranged in the guide groove.

7. The arc buckle site demoulding mechanism of claim 6, further comprising a first limit piece mounted to the fixed mould body, the first limit piece being capable of abutting the slide block to enable the insert to maintain a mould closing position.

8. The arc button site demoulding mechanism as defined in claim 7, further comprising a wear block mounted to a side of the slider adjacent the first limiting member for protecting the first limiting member and the slider.

9. The arc button demolding mechanism according to claim 7, further comprising a base, a second limiting member and a power element, wherein the second limiting member is slidably connected with the base, the power element is connected with the second limiting member and is used for driving the second limiting member to move relative to the base so that the second limiting member can abut against the first limiting member; and/or

The sliding block seat is provided with an avoidance groove, and the avoidance groove is used for avoiding the second limiting piece.

10. A mould comprising the arcuate buckle position demoulding mechanism as claimed in any one of claims 1 to 9.