CN110896615A

CN110896615A - Insert structure and plastic mold

Info

Publication number: CN110896615A
Application number: CN201880017722.4A
Authority: CN
Inventors: 袁岭
Original assignee: Dji Baiwang Technology Co ltd
Current assignee: Dji Baiwang Technology Co ltd
Priority date: 2018-03-30
Filing date: 2018-09-20
Publication date: 2020-03-20
Also published as: CN208343318U; WO2019184274A1

Abstract

An insert structure (4) and a plastic mold employing the insert structure (4), wherein the insert structure (4) comprises: the insert (10) is provided with a transmission part (101) matched with an external part; the fixing piece (20) is screwed with the insert (10) and is coaxial, and an axial limiting part (201) matched with an external part is arranged on the periphery of the fixing piece (20); the adjusting piece (30) drives the fixing piece (20) to rotate so as to adjust the screwing distance between the insert (10) and the fixing piece (20); and a locking member (40) that locks the adjustment member (30). The plastic mould comprises a fixed mould component (1), a movable mould component (2), a demoulding component (32) and the insert structure (4), wherein the demoulding component (32) and the insert structure (4) are positioned in a cavity formed by matching the fixed mould component (1) and the movable mould component (2), the demoulding component (32) comprises a transmission gear (32a), and the transmission gear (32a) is matched with a transmission part (101) on an insert in the insert structure (4). The plastic mold can correct the position of the insert (10) in the mold without disassembling the mold, and can ensure the production consistency of injection products.

Description

Insert structure and plastic mold

Technical Field

The embodiment of the invention belongs to the technical field of injection molds, and particularly relates to an insert structure and a plastic mold adopting the insert structure.

Background

In the field of moulding plastics, can set up some inserts in some multi-cavity screw demolding type plastic moulds, for example the screw thread changes the core, the insert on the one hand be the dismouting of being convenient for and changes, on the other hand to the comparatively complicated injection moulding product of structure, perhaps be difficult for the injection moulding product of demolding (for example the injection moulding product that needs processing internal thread hole), set up the insert and can make things convenient for the demolding, reduce the processing degree of difficulty.

The inventor finds that the prior art at least has the following problems in the process of implementing the embodiment of the invention: in a plastic mold provided with the insert of the type of the thread rotating core, the thread rotating core needs to be tightly matched with a fixed template or a movable template or other inserts, and if the matching is not good, an injection molding product is easy to form flash, so that the yield of the product is reduced; if the injection molding product has flash after the insert is assembled to the mold, the conventional method needs to disassemble the mold and readjust the position of the insert, which results in low production efficiency, inconsistent adjustment results each time, and poor consistency of injection molding products of different batches.

Disclosure of Invention

Based on the above background, embodiments of the present invention provide an insert structure, so as to solve the problem that when some inserts are used in an existing plastic mold, an injection molded product is prone to have flash, and solve the problems that when the product has flash, the mold needs to be disassembled to readjust the position of the insert, which results in low production efficiency and poor product consistency. In addition, the embodiment of the invention also provides a plastic mold adopting the insert structure.

The embodiment of the invention adopts the following technical scheme.

In one aspect, an insert structure provided by an embodiment of the present invention includes:

the insert is provided with a transmission part matched with an external part;

the fixing piece is screwed with the insert and coaxial, and an axial limiting part matched with an external part is arranged on the periphery of the fixing piece;

the adjusting piece drives the fixing piece to rotate so as to adjust the screwing distance between the insert and the fixing piece;

and a locking member that locks the adjusting member.

As an alternative of the present invention, the fixing member is provided with a first axial hole, and the insert may be screwed into or out of the first axial hole when the adjusting member rotates the fixing member.

As an alternative of the present invention, the first axial hole is a blind hole or a through hole, an internal thread is provided on a sidewall of the first axial hole, an external thread is provided on one end of the insert located in the first axial hole, and the insert is engaged with the fixing member through the external thread and the internal thread.

As an alternative of the present invention, the first axial hole is a blind hole, an axial threaded column is disposed at the bottom of the first axial hole, the threaded column is coaxial with the first axial hole, a second axial hole with an internal thread is disposed at one end of the insert located in the first axial hole, and the insert is engaged with the threaded column through the internal thread.

As an alternative of the present invention, a clamping member is disposed on an inner wall of the first axial hole, a clamping groove is correspondingly disposed on a portion of the insert located in the first axial hole, and when the insert is unscrewed or unscrewed for a certain distance from the first axial hole, the clamping member and the clamping groove cooperate to generate a sense of in-place.

As an alternative of the invention, the detent element comprises an elastic part and a detent part which are in contact with each other, the inner wall of the first axial hole is provided with a radial counter bore, the elastic part is located in the radial counter bore, and the detent part is partially located in the radial counter bore.

As an alternative of the present invention, the insert structure further includes a limiting member, and the limiting member cooperates with the transmission portion to limit a screwing distance between the insert and the fixing member.

As an alternative of the present invention, an external thread portion is provided at an end of the fixing portion away from the insert, and the adjusting member and the locking member are two knobs that are sequentially screwed into the external thread portion.

Optionally, the insert in the above scheme is a threaded core.

On the other hand, the embodiment of the invention provides a plastic mold, which comprises a fixed mold component, a movable mold component, a demolding component and the insert structure, wherein the demolding component is positioned in a cavity formed by matching the fixed mold component and the movable mold component, and the insert structure is arranged in the cavity, wherein the demolding component comprises a transmission gear, and the transmission gear is matched with a transmission part on an insert in the insert structure.

According to the insert structure and the injection mold adopting the insert structure provided by the embodiment of the invention, by arranging the fixing piece and the adjusting piece which are matched with the insert, the matching tightness of the insert and other parts in the mold can be adjusted by adjusting the screwing distance between the insert and the fixing piece through the adjusting piece, so that the position of the insert in the mold is corrected under the condition of not dismounting the mold, the generation of flash is prevented, the production efficiency can be effectively improved, the adjustment amount of each time can be kept at the same level, and the consistency of injection products is ensured.

Drawings

While the drawings needed to describe the invention or prior art arrangements in a more complete description of the embodiments or prior art are briefly described below, it should be apparent that the drawings described below are illustrative of some embodiments of the invention and that other drawings may be derived therefrom by those skilled in the art without the benefit of the inventive faculty.

Fig. 1 is a general schematic view of an insert structure provided by an embodiment of the present invention;

fig. 2 is a cross-sectional view of the insert structure provided in fig. 1;

fig. 3 is a cross-sectional view of another insert structure provided by an embodiment of the present invention;

FIG. 4 is an enlarged view of A in FIG. 3;

FIG. 5 is a top view of a plastic mold according to an embodiment of the present invention;

FIG. 6 is a cross-sectional view taken along section B-B of FIG. 5;

FIG. 7 is a cross-sectional view taken along section line C-C of FIG. 5;

FIG. 8 is a partial view of the plastic mold provided in FIG. 5;

fig. 9 is an enlarged schematic view of D in fig. 8.

1 fixed die assembly

11 inlaying the hole

2 moving die assembly

31 driving mechanism

32 stripper assembly

32a transmission gear

4 insert structure

10 insert

101 transmission part

102 second axial hole

103 card slot

20 fixing piece

201 axial limiting part

202 first axial hole

203 threaded post

204 position fastener

2041 elastic part

2042 position-clamping part

205 radial counter bore

30 adjustment piece

40 locking element

50 position limiting part

Detailed Description

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs; the terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention; the terms "comprising" and "having," and any variations thereof, in the description and claims of this invention and the description of the above figures, are intended to cover non-exclusive inclusions. The terms "first," "second," and the like in the description and in the claims, or in the drawings, are used for distinguishing between different objects and not necessarily for describing a particular sequential order.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the invention. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

The embodiment of the invention provides an insert structure, which comprises:

the insert is provided with a transmission part matched with an external part;

and a locking member that locks the adjusting member.

Based on the insert structure, the embodiment of the invention further provides a plastic mold, which comprises a fixed mold component, a movable mold component, a demolding component and the insert structure, wherein the demolding component is positioned in a cavity formed by matching the fixed mold component and the movable mold component, and the insert structure is arranged in the cavity, wherein the demolding component comprises a transmission gear, and the transmission gear is matched with a transmission part on an insert in the insert structure.

In order to make the technical solutions of the embodiments of the present invention better understood, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention.

Referring to fig. 1, there is shown an overall structure diagram of an insert structure according to an embodiment of the present invention, the insert structure may be applied to a plastic mold, especially a multi-cavity screw demolding type plastic mold, and specifically, the insert structure includes an insert 10, a fixing member 20, an adjusting member 30, and a locking member 40; the fixing part 20 is screwed and coaxial with the insert 10, and the adjusting part 30 drives the fixing part 20 to rotate so as to adjust the screwing distance between the insert 10 and the fixing part 20; the locking member 40 is used to lock the adjustment member 30 after the adjustment member 30 has adjusted the screwing distance between the insert 10 and the fixing member 20.

Further, referring to fig. 2, the insert 10 is provided with a transmission portion 101 cooperating with an external component, in this embodiment, the external component may be a transmission gear in a demolding assembly of a plastic mold, and the transmission portion 101 corresponds to a gear portion.

An axial limiting portion 201 matched with an external part is arranged on the periphery of the fixing member 20, in this embodiment, the external part may be a fixed mold plate in a plastic mold, the fixed mold plate is matched with the axial limiting portion 201 to limit axial movement of the fixing member 20, the fixing member 20 is driven by the adjusting member 30 to only perform circumferential rotation movement but not axial movement, so that when the adjusting member 30 rotates, the insert 10 screwed with the adjusting member 30 can perform linear movement along an axis of the adjusting member 30, so as to adjust the position of the insert 10 in the plastic mold, realize adjustment of tightness of matching of the insert 10 and other parts in the plastic mold, and avoid a situation of flash of a plastic product; since the rotation angle of the fixing member 20 is controllable, a uniform adjustment amount can be secured to the maximum, thereby securing the uniformity of the plastic product.

As an embodiment of the present invention, the screwing of the fixing member 20 to the insert 10 can be realized by sleeving the fixing member 20 on the outside of the insert 10, which is described as an example below, and referring to fig. 2 again, a first axial hole 202 can be provided at one end of the fixing member 20, the insert 10 is partially located in the first axial hole 202, and the insert 10 can be screwed into or out of the first axial hole 202 when the adjusting member 30 rotates the fixing member 20. In an alternative embodiment, the first axial hole 202 is a blind hole or a through hole, the sidewall of the first axial hole 202 is provided with an internal thread, the end of the insert 10 located in the first axial hole 202 is provided with an external thread, the insert 10 is engaged with the fixing member 20 through the external thread and the internal thread, when the fixing member 20 is rotated by the adjusting member 30, the screwing distance between the adjusting member 30 and the insert 10 is changed, that is, the insert 10 is screwed into or out of the first axial hole 202; in another alternative embodiment, as shown in fig. 3, the first axial bore 202 is a blind bore, the bottom of the first axial hole 202 is provided with an axial threaded post 203, the threaded post 203 being coaxial with the first axial hole 202, the insert 10 is provided with an internally threaded second axial bore 102 at the end located within the first axial bore 202, the insert 10 engages the threaded post 203 via internal threads in the second axial bore 102, when the adjusting part 30 rotates the fixing part 20, the screwing distance between the adjusting part 30 and the insert 10 changes, the threaded post 203 screws in or out of the second axial bore 102, the insert 10 correspondingly screws in or out of the first axial bore 202, in this embodiment, the threaded post 203 may be an integral structure with the fixing member 20, or may be a screw passing through an end of the fixing member 20.

Of course, in other embodiments, the screwing connection between the fixing member 20 and the insert 10 may also be achieved by sleeving the insert 10 on the outside of the fixing member 20, which is similar to the sleeving connection between the fixing member 20 and the insert 10, and will not be described herein.

As an implementation solution of the present invention, the inner wall of the first axial hole 202 is further provided with a detent 204, the insert 10 is provided with a clamping groove 103 at a portion corresponding to the first axial hole 202, the engagement of the detent element 204 and the detent slot 103 may provide a feel to the user when adjusting the rotational distance of the holder 20 and the insert 10, that is, when the insert 10 is screwed into or out of the first axial hole 202 for a certain distance, the detent 204 slides into the detent 103 to generate a sense of positioning, the position of the detent 204 in the first axial hole 202 may be set according to the screwing distance between the insert 10 and the fixture 20 when the insert 10 is tightly fitted to a part in a plastic mold, so that when the detent 204 slides into the slot 103 to generate a proper feeling, the insert 10 fits snugly with the parts in the plastic mold to inhibit the formation of flash on the plastic product.

In some embodiments, two axially distributed clamping grooves 103 may be disposed on the outer wall of the insert 10, wherein the in-place feeling generated by the matching of one clamping groove 103 and the blocking element 204 corresponds to the tight matching state of the insert 10 and a part in a plastic mold, and the in-place feeling generated by the matching of the other clamping groove 103 and the blocking element 204 corresponds to the state that the demolding of the insert 10 and a plastic product is completed; of course, two axially distributed detent elements 204 may also be disposed on the inner wall of the first axial hole 202, wherein an in-place feeling generated by the cooperation of one detent element 204 and the slot 103 corresponds to a state of tight fitting between the insert 10 and a component in the plastic mold, and an in-place feeling generated by the cooperation of the other detent element 204 and the slot 103 corresponds to a state of complete demolding between the insert 10 and the plastic product.

Further, in this embodiment, as shown in fig. 4, the detent 204 may include an elastic portion 2041 and a detent portion 2042 that contact or connect with each other, a radial counter bore 205 is disposed on an inner wall of the first axial hole 202, the elastic portion 2041 is located in the radial counter bore 205, and the detent portion 2042 is partially located in the radial counter bore 205, in this embodiment, a side of the detent portion 2042 that is engaged with the detent slot 103 is configured as a curved surface structure, and further, the detent slot 103 may also be configured as a curved surface structure, so as to ensure that the detent 204 can slide in or out of the detent slot 103 smoothly.

Of course, in other embodiments, the detent element 204 and the slot 103 that generate the in-place feeling may be replaced by a spring plate plus a boss or other manners that can achieve the in-place feeling, and will not be described herein. In other embodiments, the detent element 204 may also be disposed on the outer wall of the insert 10, and the detent groove 103 is correspondingly disposed on the inner wall of the first axial hole 202, and the specific arrangement may refer to the description of the above embodiments, and will not be further described herein.

As an implementation scheme of the present invention, the insert structure further includes a limiting member 50, the limiting member 50 is sleeved on the insert 10, the limiting member 50 cooperates with the transmission portion 101 to limit a movement range of the insert 10, that is, a rotation distance or a variation range of the rotation distance between the insert 10 and the fixing member 20, specifically, the limiting member 50 is fixed in a fixed mold plate of a plastic mold, so that when the insert 10 rotates out of the fixing member 20 by a certain distance, the transmission portion 101 just abuts against the limiting member 50, a limiting function on the insert 10 is realized, and the insert 10 is prevented from being in interference fit with other components in the plastic mold, thereby reducing a probability of damage to the mold and improving service lives of the insert 10 and the plastic mold.

In an embodiment of the present invention, an external thread portion is provided at an end of the fixing portion away from the insert 10, the adjusting member 30 and the locking member 40 are knobs, and the adjusting member and the locking member 40 are sequentially screwed into the external thread portion.

In the above solution of the present invention, the insert 10 may be a threaded core, and the threaded core may form an internal threaded hole in a plastic product.

Compared with the prior art, the insert structure provided by the embodiment of the invention at least has the following advantages:

by arranging the fixing part 20 and the adjusting part 30 which are matched with the insert 10, after the insert structure is assembled to a mold, the matching tightness between the insert 10 and other parts in the mold can be adjusted by adjusting the screwing distance between the insert 10 and the fixing part 20 through the adjusting part 30, so that the position of the insert 10 in the mold is corrected under the condition of not dismounting the mold, the generation of flash is prevented, and the production efficiency can be effectively improved; the adjustment amount of each time can be kept at the same level, so that the consistency of injection molding products is ensured.

The embodiment of the present invention further provides a plastic mold, referring to fig. 5 to 7, where fig. 5 is a top view of the plastic mold, and fig. 6 and 7 are cross-sectional views of the plastic mold at different positions, specifically, the plastic mold includes a fixed mold component 1, a movable mold component 2, and a demolding component 32 and an insert structure 4 located in a cavity (not labeled in the figures) formed by the fixed mold component 1 and the movable mold component 2 in a matching manner, where the insert structure 4 may refer to the insert structure provided in the foregoing embodiment, and is not described herein again; the demolding assembly 32 is connected to a driving mechanism 31 outside the cavity, and includes a transmission gear 32a, and the transmission gear 32a is matched with the transmission part 101 on the insert 10 in the insert structure 4.

The operation of the insert structure 4 in the plastic mold is described with reference to fig. 8 and 9 in conjunction with fig. 1-4.

If the insert 10 in the insert structure 4 is separated from the insert hole 11 in the plastic mold in the initial state, that is, the mold core (not shown) in the plastic mold of the insert 10 is not tightly fitted, the plastic product is produced in this state, and therefore, the flash is inevitably generated.

Firstly, the adjusting member 30 is operated by a tool such as a wrench, so that the adjusting member 30 drives the fixing member 20 to rotate in a specific direction, and further drives the insert 10 to be unscrewed from the fixing portion and move towards the insert hole 11, and after rotating a certain angle, if the fixing member 20 is continuously driven to rotate by the adjusting member 30, a sense of force is generated, or if the clamping groove 103 on the insert 10 and the clamping member 204 on the fixing member 20 generate a sense of in-place when being tightly matched, it indicates that the matching between the insert 10 and the mold core in the plastic mold is relatively tight, and at this time, the fixing member 20 stops rotating;

then, a locking member 40 is further operated by a tool such as a wrench, so that the locking member 40 is rotated to a position abutting against the adjusting member 30, so that the adjusting member 30 and the locking member 40 generate a self-locking force to fix the fixing member 20, and the insert 10 is ensured not to be displaced during the production process, thereby completing the adjustment of the insert 10.

Further describing the mold unloading process of the insert 10 after the injection molding is completed, as shown in fig. 8, specifically, under the driving of a transmission rack (not shown) and a transmission shaft (not shown) of a driving mechanism 31, the transmission gear 32a rotates, the transmission gear 32a drives the insert 10 to rotate, the insert 10 rotates and moves downward to be screwed into the first axial hole 202 of the fixing member 20, meanwhile, due to the fact that the screw teeth of the insert 10 located in the plastic product correspond to the internal screw teeth of the plastic product, the insert 10 rotates and is screwed out of the plastic product along the internal screw teeth, and when the insert 10 is completely screwed out of the plastic product, the separation of the insert 10 from the plastic product is achieved, and the mold unloading is completed. Thereafter, if the transmission gear 32a is rotated reversely, the insert 10 may be moved reversely to be closely matched with the mold core in the plastic mold, and if the transmission gear 32a drives the insert 10 to rotate and then not to be closely matched with the mold core, the process of adjusting the insert 10 may be repeated to adjust the tightness between the insert 10 and the mold core.

The plastic mold provided by the embodiment of the invention adopts the insert structure 4 described in the above embodiment, and compared with the prior art, the plastic mold has at least the following advantages:

by arranging the fixing part 20 and the adjusting part 30 which are matched with the insert 10, the screwing distance between the insert 10 and the fixing part 20 can be adjusted through the adjusting part 30 to adjust the matching tightness between the insert 10 and other parts in the mold, so that the position of the insert 10 in the mold is corrected under the condition of not dismounting the mold, the generation of flash is prevented, and the production efficiency can be effectively improved; meanwhile, the operation is simple, and the daily maintenance of the plastic mold is convenient; in addition, the adjustment amount of each time can be kept at the same level, so that the consistency of injection molding products is ensured.

It is to be understood that the above-described embodiments are merely illustrative of some, but not restrictive, of the broad invention, and that the appended drawings illustrate preferred embodiments of the invention without limiting its scope. This invention may be embodied in many different forms and, on the contrary, these embodiments are provided so that this disclosure will be thorough and complete. Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that various changes in the embodiments and modifications can be made, and equivalents may be substituted for elements thereof. All equivalent structures made by using the contents of the specification and the attached drawings of the invention can be directly or indirectly applied to other related technical fields, and are also within the protection scope of the patent of the invention.

Claims

1. An insert structure, comprising:

the insert is provided with a transmission part matched with an external part;

and a locking member that locks the adjusting member.

2. The insert structure according to claim 1, wherein the fixture is provided with a first axial bore in which the insert may be screwed in or out as the adjuster rotates the fixture.

3. The insert structure according to claim 2, wherein the first axial bore is a blind or through bore, the sidewall of the first axial bore is provided with internal threads, the end of the insert within the first axial bore is provided with external threads, and the insert is engaged with the fixture through the external threads and the internal threads.

4. The insert structure according to claim 2, wherein the first axial bore is a blind bore, the bottom of the first axial bore is provided with an axially threaded post coaxial with the first axial bore, the end of the insert within the first axial bore is provided with a second axial bore with internal threads, and the insert is engaged with the threaded post via the internal threads.

5. The insert structure according to claim 3 or 4, wherein a position-retaining member is disposed on an inner wall of the first axial hole, a locking groove is correspondingly disposed on a portion of the insert located in the first axial hole, and when the insert is unscrewed or unscrewed from the first axial hole for a certain distance, the position-retaining member and the locking groove cooperate to generate a position-retaining feeling.

6. The insert structure according to claim 5, wherein the detent member comprises a resilient portion and a detent portion in contact with each other, the inner wall of the first axial bore being provided with a radial counterbore, the resilient portion being located within the radial counterbore, the detent portion being located partially within the radial counterbore.

7. The insert structure according to claim 1, further comprising a stopper that cooperates with the transmission portion to limit a screwing distance of the insert to the fixture.

8. The insert structure according to claim 1, wherein the fixing portion is provided with an externally threaded portion at an end thereof remote from the insert, and the adjusting member and the locking member are two knobs that are sequentially screwed into the externally threaded portion.

9. The insert structure according to claim 1, wherein the insert is a threaded core.

10. A plastic mold is characterized by comprising a fixed mold component, a movable mold component, a demolding component and an insert structure, wherein the demolding component and the insert structure are positioned in a cavity formed by matching the fixed mold component and the movable mold component;

the insert structure includes:

the insert is provided with a transmission part matched with an external part;

and a locking member that locks the adjusting member.

11. The plastic mold as defined in claim 10, wherein the fixture is provided with a first axial bore, the insert being threaded into or out of the first axial bore when the adjustment member rotates the fixture.

12. The plastic mold as defined in claim 11, wherein the first axial bore is a blind or through bore, a sidewall of the first axial bore is provided with an internal thread, an end of the insert within the first axial bore is provided with an external thread, and the insert is engaged with the fixture via the external thread and the internal thread.

13. The plastic mold as claimed in claim 11, wherein the first axial hole is a blind hole, the bottom of the first axial hole is provided with an axial threaded post, the threaded post is coaxial with the first axial hole, one end of the insert located in the first axial hole is provided with a second axial hole with an internal thread, and the insert is engaged with the threaded post through the internal thread.

14. The plastic mold according to claim 12 or 13, wherein a retaining member is disposed on an inner wall of the first axial hole, a locking groove is correspondingly disposed on a portion of the insert located in the first axial hole, and when the insert is unscrewed or a certain distance is unscrewed from the first axial hole, the retaining member and the locking groove cooperate to generate a sense of being in place.

15. The plastic mold as recited in claim 14, wherein the detent element comprises an elastic portion and a detent portion that contact each other, the inner wall of the first axial bore is provided with a radial counterbore, the elastic portion is located within the radial counterbore, and the detent portion is partially located within the radial counterbore.

16. The plastic mold as recited in claim 10, further comprising a stop that cooperates with the drive portion to limit a rotational coupling distance between the insert and the fixture.

17. The plastic mold as claimed in claim 10, wherein the fixing portion is provided with an external thread portion at an end thereof away from the insert, and the adjusting member and the locking member are two knobs which are sequentially screwed into the external thread portion.

18. The plastic mold of claim 10, wherein the insert is a threaded core.