CN218640134U

CN218640134U - Tire vulcanization mold

Info

Publication number: CN218640134U
Application number: CN202223250342.8U
Authority: CN
Inventors: 李健; 孙日文; 刘卫华; 刘海明; 单上; 张长春
Original assignee: Himile Mechanical Science and Technology Shandong Co Ltd
Current assignee: Himile Mechanical Science and Technology Shandong Co Ltd
Priority date: 2022-12-01
Filing date: 2022-12-01
Publication date: 2023-03-17
Anticipated expiration: 2032-12-01

Abstract

The invention relates to the technical field of tire production equipment, and discloses a tire vulcanization mold, which comprises a mold body and a plurality of heating coils, wherein a plurality of mounting grooves are formed in the peripheral side wall of the mold body; the heating coils are of multi-turn coil structures arranged around the peripheral side wall of the die body, and the heating coils are correspondingly arranged in the mounting grooves one by one; the installation groove is formed in the peripheral side wall of the mold body, so that the heating coil is installed on the outer side of the mold body, the convenience for installing the heating coil is improved, and meanwhile, the heating coil in an abnormal working state can be conveniently overhauled and replaced in time, so that the vulcanization effect of the tire is ensured; through setting up a plurality of mounting grooves to correspond a plurality of heating coil and set up in the mounting groove, can transfer into every induction coil's power according to the heating demand at the different positions of mould body, with the difference in temperature that reduces the different positions of mould body, with the vulcanization effect that promotes the tire, promote the vulcanization quality.

Description

Tire vulcanization mold

Technical Field

The utility model relates to a tire production facility technical field especially relates to a tire vulcanization mould utensil.

Background

In a conventional tire vulcanization process, a steam chamber is arranged in a mold, and high-temperature steam is continuously introduced during tire vulcanization to realize heat transfer. The heat of the steam heating mode can not be fully utilized, the energy utilization rate is lower than 30 percent, the consumption is high, and the steam heating is difficult to adjust the vulcanization temperature, so that the debugging and optimization of the vulcanization process of a tire factory are not facilitated.

In order to solve the problems existing in steam vulcanization, the prior art provides an electric heating tire mold which has outstanding advantages in the aspects of energy conservation and consumption reduction, but in the actual use process, a heating pipe is often arranged inside a guide ring, so that the problem that the heating pipe is extremely difficult to install, overhaul and replace is caused; in addition, the distance between the mounting surface of the heating pipe and the cavity surface of the mold is uneven, so that the temperature difference of different parts of the guide ring is large in the vulcanization process, the vulcanization temperature is difficult to control, the tire vulcanization efficiency is low, and the problems of insufficient local vulcanization and local over vulcanization exist.

Disclosure of Invention

In order to solve the technical problem, the present disclosure provides a tire vulcanizing mold.

The present disclosure provides a tire vulcanization mold, including: the die comprises a die body, wherein a plurality of mounting grooves are formed in the peripheral side wall of the die body; the heating coil is a multi-turn coil structure which is arranged around the peripheral side wall of the die body, the number of the heating coils is multiple, and the heating coils are arranged in the mounting grooves in a one-to-one correspondence mode.

Optionally, the number of coil turns of at least two of the plurality of heating coils is different; and/or the distance between adjacent turns of at least two of the heating coils is different.

Optionally, the mounting grooves are in an annular groove structure, and the mounting grooves are arranged at intervals along the mold opening direction of the mold body.

Optionally, the mounting groove is of a spiral groove structure, the mounting grooves are arranged at intervals along the mold opening direction of the mold body, and the heating coil is arranged in the mounting groove along the spiral direction of the mounting groove.

Optionally, in the plurality of mounting grooves, the thread pitches of at least two mounting grooves are different.

Optionally, a plurality of steps which are close to a central shaft of the die body step by step along a die opening direction are formed on the peripheral side wall of the die body, and at least one mounting groove is formed on the peripheral side wall of each step; or, be formed with on the periphery lateral wall of mould body and be close to gradually along the die sinking direction the conical surface of the center pin of mould body, it is a plurality of the mounting groove all sets up on the conical surface.

Optionally, the mould body is an upper-opening segmented mould, the mould body comprises a guide ring, a base, pattern blocks and an upper cover, the base is arranged at the lower end of the guide ring, the upper cover is slidably connected to the upper end of the guide ring, the pattern blocks are slidably arranged in the guide ring, and the mounting grooves are formed in the peripheral side wall of the guide ring.

Optionally, the mould body is an under-opening segmented mould, the mould body comprises a guide ring, a base, pattern blocks and an upper cover, the base is slidably connected to the lower end of the guide ring, the upper cover is detachably arranged at the upper end of the guide ring, the pattern blocks are slidably arranged in the guide ring, and the mounting grooves are formed in the peripheral side wall of the guide ring.

Optionally, the mold body is a two-half segmented mold, the mold body includes an upper mold part and a lower mold part which are oppositely arranged, the upper mold part includes an upper guide ring, an upper cover and an upper pattern block, the upper cover is arranged at the upper end of the upper guide ring, and the upper pattern block is slidably arranged in the upper guide ring; the lower die part comprises a lower guide ring, a base and lower pattern blocks, the base is arranged at the lower end of the lower guide ring, the lower pattern blocks are arranged in the lower guide ring in a sliding mode, at least one of the installation grooves is arranged on the peripheral side wall of the upper guide ring, and the rest installation grooves are arranged on the peripheral side wall of the lower guide ring.

Optionally, the mold body is a two-half mold, the mold body includes an upper mold and a lower mold which are arranged oppositely, at least one of the mounting grooves is arranged on the peripheral side wall of the upper mold, and the other mounting grooves are arranged on the peripheral side wall of the lower mold.

Compared with the prior art, the technical scheme provided by the embodiment of the disclosure has the following advantages:

according to the tire vulcanizing mold, the plurality of mounting grooves are formed in the peripheral side wall of the mold body and are used for mounting the heating coils respectively, so that the heating coils are located on the outer side of the mold body, convenience in mounting the heating coils is improved, meanwhile, the heating coils in abnormal working states can be maintained and replaced conveniently in time, and heat energy provided by the heating coils can reach a preset standard so as to guarantee the vulcanizing effect on tires; and through setting up a plurality of mounting grooves to set up a plurality of heating coils that have multiturn coil structure of one-to-one in a plurality of mounting grooves, be used for making a plurality of heating coils encircle respectively on the periphery lateral wall of mould body, and heat corresponding mould body's different positions, can transfer into to every induction coil's power according to the heating demand of difference, with the difference in temperature that reduces mould body different positions, with the vulcanization effect that promotes the tire, promote vulcanization quality.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and together with the description, serve to explain the principles of the disclosure.

In order to more clearly illustrate the embodiments or technical solutions in the prior art of the present disclosure, the drawings used in the description of the embodiments or prior art will be briefly described below, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive exercise.

FIG. 1 is a schematic view of a tire curing mold according to a first embodiment of the present disclosure;

FIG. 2 is a schematic view of a tire curing mold according to a second embodiment of the present disclosure;

FIG. 3 is a schematic view of a tire curing mold according to a third embodiment of the present disclosure;

FIG. 4 is a schematic view of a tire curing mold according to a fourth embodiment of the present disclosure;

FIG. 5 is a schematic view of a tire curing mold according to a fifth embodiment of the present disclosure;

fig. 6 is a schematic view of a tire curing mold according to a sixth embodiment of the present disclosure.

Wherein, 1, a mould body; 11. mounting grooves; 12. a guide ring; 13. a base; 14. pattern blocks; 15. an upper cover; 16. an upper die; 161. an upper guide ring; 163. an upper pattern block; 17. a lower die; 171. a lower guide ring; 173. a lower pattern block; 2. a heating coil; 3. an insulating sleeve.

Detailed Description

In order that the above objects, features and advantages of the present disclosure may be more clearly understood, aspects of the present disclosure will be further described below. It should be noted that the embodiments and features of the embodiments of the present disclosure may be combined with each other without conflict.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure, but the present disclosure may be practiced in other ways than those described herein; it is to be understood that the embodiments disclosed in the specification are only a few embodiments of the present disclosure, and not all embodiments.

Some embodiments of the present disclosure, as illustrated in connection with fig. 1-6, provide a tire curing mold comprising: the die comprises a die body 1, wherein a plurality of mounting grooves 11 are formed in the peripheral side wall of the die body 1; heating coil 2, heating coil 2 are the multiturn coil structure that sets up around the periphery lateral wall of mould body 1, and heating coil 2's quantity is a plurality of, and a plurality of heating coil 2 one-to-one sets up in a plurality of mounting grooves 11.

According to the tire vulcanizing mold provided by the embodiment, the plurality of mounting grooves 11 are formed in the peripheral side wall of the mold body 1 and are used for mounting the heating coils 2 respectively, so that the heating coils 2 are positioned outside the mold body 1, the convenience for mounting the heating coils 2 is improved, meanwhile, the heating coils 2 in abnormal working states can be conveniently overhauled and replaced in time, and the heat energy provided by the heating coils 2 can reach the preset standard so as to ensure the vulcanizing effect on tires; and through setting up a plurality of mounting grooves 11 to set up a plurality of heating coil 2 that have multiturn coil structure of one-to-one in a plurality of mounting grooves 11, be used for making a plurality of heating coil 2 encircle respectively on the periphery lateral wall of mould body 1, and heat corresponding mould body 1's different positions, can adjust into every induction coil's power according to the heating demand of difference, with the difference in temperature that reduces mould body 1 different positions.

By adopting the tire vulcanizing mold, the heating coils 2 can be arranged in the mounting grooves 11 formed in the peripheral side wall of the mold body 1 in a one-to-one correspondence manner, so that the heating coils 2 can be conveniently mounted, maintained and overhauled; in addition, a plurality of heating coils 2 both can set up to different turns, different power, also can control every heating coil 2 respectively through setting up a plurality of controllers to the temperature difference between the different positions of control mould body 1 promotes the vulcanization efficiency of tire, makes the even vulcanization of tire.

In some more detailed embodiments, the periphery of the mold body 1 is provided with a thermal insulation sleeve 3 for reducing heat exchange between the mold body 1 and the external environment, and improving heating efficiency.

The heating coil 2 may be an electromagnetic induction heating coil or a resistance heating coil.

Illustratively, the heating coils 2 are electromagnetic induction heating coils, and in some further embodiments, the number of coil turns of at least two heating coils 2 among the plurality of heating coils 2 is different; and/or the distance between adjacent turns of at least two heating coils 2 is different. Specifically, the larger the diameter of the heating coil 2 is, or the larger the distance between the heating coil 2 and the die cavity is, the smaller the number of turns of the heating coil 2 is, and the higher the heating power is.

In some embodiments, as shown in fig. 1, 2 and 4, the mounting groove 11 is an annular groove structure, and a plurality of mounting grooves 11 are spaced along the mold opening direction of the mold body 1. Specifically, the mounting groove 11 of ring channel structure both is convenient for design and processing, is convenient for assemble with heating coil 2 again, and a plurality of mounting grooves 11 both can equidistant setting also can be according to specific heating demand setting different intervals. Further, can make heating coil 2 directly carry on spacingly with the joint portion joint in the mounting groove 11, also can fix heating coil 2 in mounting groove 11 through clamp plate or wire clip.

In other embodiments, as shown in fig. 3, the mounting groove 11 is a spiral groove structure, a plurality of mounting grooves 11 are arranged at intervals along the mold opening direction of the mold body 1, and the heating coil 2 is arranged in the mounting groove 11 along the spiral direction of the mounting groove 11. Specifically, have great contact surface between the mounting groove 11 of helicla flute structure and heating coil 2, can be better carry on spacingly to heating coil 2, can enough reduce the setting quantity reduction in production cost of mounting, promote assembly efficiency, can guarantee the stability of heating coil 2 in mounting groove 11 again.

Furthermore, the thread pitches of at least two installation grooves 11 in the plurality of installation grooves 11 are different. Specifically, different pitches of the mounting groove 11 can correspond to different distances between adjacent turns of the heating coil 2 for adjusting the heating power of the heating coil 2.

In some further embodiments, as shown in fig. 1 to 3, a plurality of steps are formed on the outer peripheral side wall of the mold body 1 in a step-by-step manner to be close to the central axis of the mold body 1 along the mold opening direction, and at least one mounting groove 11 is formed on the outer peripheral side wall of each step.

In other embodiments, as shown in fig. 4, a tapered surface is formed on the outer peripheral side wall of the die body 1 so as to gradually approach the central axis of the die body 1 along the opening direction, and the plurality of mounting grooves 11 are all arranged on the tapered surface.

Specifically, the size of the mold body 1 can be reduced and the weight of the mold body 1 can be reduced by arranging steps which are gradually close to the central axis of the mold body 1 along the mold opening direction, or conical surfaces which are gradually close to the central axis of the mold body 1 along the mold opening direction on the premise of not influencing the mold opening of the tire vulcanization mold; through set up a plurality of mounting grooves 11 on the periphery lateral wall of foretell mould body 1 and be used for installing corresponding heating coil 2, can cross and form a plurality of zone of heating on mould body 1 surface, the heating power in a plurality of zones of heating can be adjusted according to the distance between mould body 1 periphery lateral wall surface and the mould die cavity face to reduce the difference in temperature between the different positions of mould body 1, make the vulcanization of tire more even.

The structure of the tire vulcanizing mold of the present disclosure is described in detail below in conjunction with a specific form of the tire vulcanizing mold.

The first embodiment is as follows: as shown in fig. 1, the mold body 1 is an upper-opening segmented mold, the mold body 1 includes a guide ring 12, a base 13, a pattern block 14 and an upper cover 15, the base 13 is disposed at the lower end of the guide ring 12, the upper cover 15 is slidably connected to the upper end of the guide ring 12, the pattern block 14 is slidably disposed in the guide ring 12, and the plurality of mounting grooves 11 are disposed on the peripheral side wall of the guide ring 12. A plurality of steps close to the central shaft of the die body 1 from bottom to top are arranged on the guide ring 12 step by step, and a mounting groove 11 can be formed on the peripheral side wall of each step for mounting the corresponding heating coil 2.

Specifically, two steps are formed on the outer peripheral side wall of the guide ring 12, an installation groove 11 with an annular groove structure is formed on the outer peripheral side wall of each step, the two heating coils 2 are respectively and correspondingly arranged in the two installation grooves 11, the average distance between adjacent turns of the heating coil 2 located above is larger than the average distance between adjacent turns of the heating coil 2 located below, and the power of each induction heating coil 2 can be adjusted according to the heating requirements of different parts of the die body 1 so as to reduce the temperature difference of different parts of the guide ring 12.

Example two: as shown in fig. 2, the mold body 1 is an upper-open segmented mold, and the structure of the mold body 1 can refer to the first embodiment. Specifically, two steps are formed on the outer peripheral side wall of the guide ring 12, the mounting grooves 11 of two annular groove structures are respectively formed on the outer peripheral side wall of each step, the four heating coils 2 are respectively and correspondingly arranged in the four mounting grooves 11, and the number of turns of the heating coils 2 in at least two mounting grooves 11 is different, so that the power of each induction heating coil 2 can be adjusted according to the heating requirements of different positions of the die body 1, and the temperature difference of different positions of the guide ring 12 is reduced.

Example three: as shown in fig. 3, the mold body 1 is an upper-open segmented mold, and the internal structure of the mold body 1 can refer to the first embodiment. A plurality of steps which are close to the central shaft of the die body 1 step by step from bottom to top are arranged on the guide ring 12, a mounting groove 11 is formed in the peripheral side wall of each step and used for mounting the corresponding heating coil 2, and the mounting groove 11 is a spiral groove.

Specifically, two steps are formed on the guide ring 12, an installation groove 11 with a spiral groove structure is formed on the outer peripheral side wall of each step, and the two heating coils 2 are correspondingly arranged in the two installation grooves 11 respectively.

Example four: as shown in fig. 4, the mold body 1 is an upper-opening segmented mold, and the internal structure of the mold body 1 can refer to the first embodiment. A tapered surface gradually approaching the central axis of the die body 1 from bottom to top is formed on the peripheral side wall of the guide ring 12, a plurality of mounting grooves 11 are arranged on the tapered surface at intervals, and the mounting grooves 11 are all annular grooves arranged along the periphery of the tapered surface and used for mounting corresponding heating coils 2.

Specifically, the outer peripheral side wall of the guide ring 12 is provided with two mounting grooves 11 with annular groove structures along the outer periphery of the conical surface, the two heating coils 2 are respectively and correspondingly arranged in the two mounting grooves 11, the average distance between adjacent turns of the heating coil 2 positioned above is greater than the average distance between adjacent turns of the heating coil 2 positioned below, and the power of each induction heating coil 2 can be adjusted according to the heating requirements of different parts of the die body 1, so as to reduce the temperature difference of different parts of the guide ring 12.

Example five: the mould body 1 is the loose mould of open down, and mould body 1 includes guide ring 12, base 13, decorative block 14 and upper cover 15, and base 13 sliding connection is at the lower extreme of guide ring 12, and upper cover 15 detachable sets up in the upper end of guide ring 12, and decorative block 14 slidable sets up in guide ring 12, and a plurality of mounting grooves 11 all set up on the periphery lateral wall of guide ring 12.

Specifically, the installation grooves 11 and the heating coils 2 on the outer peripheral wall of the guide ring 12 can be arranged in the manner described in the first to fourth embodiments, and in this example, the average distance between the adjacent upper turns is smaller than the average distance between the adjacent lower turns, so as to reduce the temperature difference between different parts of the guide ring 12.

Example six: as shown in fig. 5, the mold body 1 is a two-half segmented mold, the mold body 1 includes an upper mold part and a lower mold part which are oppositely arranged, the upper mold part includes an upper guide ring 161, an upper cover 15 and upper blocks 163, the upper cover 15 is arranged at the upper end of the upper guide ring 161, and the upper blocks 163 are slidably arranged in the upper guide ring 161; the lower mold portion includes a lower guide ring 171, a base 13, and lower blocks 173, the base 13 is disposed at a lower end of the lower guide ring 171, the lower blocks 173 are slidably disposed in the lower guide ring 171, at least one of the plurality of mounting grooves 11 is disposed on an outer circumferential sidewall of the upper guide ring 161, and the remaining mounting grooves 11 are disposed on an outer circumferential sidewall of the lower guide ring 171.

Specifically, the above-mentioned installation grooves 11 and the corresponding heating coils 2 are disposed on the upper guide ring 161 and the lower guide ring 171 in a manner as described in the first to fourth embodiments; alternatively, the mounting groove 11 and the heating coil 2 are symmetrically arranged about the central cross section of the cavity surface of the mold.

Example seven: as shown in fig. 6, the mold body 1 is a two-half mold, the mold body 1 includes an upper mold 16 and a lower mold 17 which are oppositely arranged, at least one of the plurality of mounting grooves 11 is arranged on the peripheral side wall of the upper mold 16, and the rest of the mounting grooves 11 are arranged on the peripheral side wall of the lower mold 17. Specifically, the above-described installation grooves 11 and the corresponding heating coils 2 are provided on the upper die 16 and the lower die 17 in a manner as described with reference to the first to fourth embodiments; alternatively, the mounting groove 11 and the heating coil 2 are symmetrically disposed about the center cross section of the cavity surface of the mold.

In the description of the embodiments of the present disclosure, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "height", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience in describing the embodiments of the present disclosure and for simplification of description, but do not indicate or imply that the structures or devices referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus are not to be construed as limiting the embodiments of the present disclosure.

It is noted that, in this document, relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising a … …" does not exclude the presence of another identical element in a process, method, article, or apparatus that comprises the element.

The previous description is only for the purpose of describing particular embodiments of the present disclosure, so as to enable those skilled in the art to understand or implement the present disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A tire curing mold, comprising:

the die comprises a die body (1), wherein a plurality of mounting grooves (11) are formed in the peripheral side wall of the die body (1);

the heating coil (2) is of a multi-turn coil structure arranged around the peripheral side wall of the die body (1), the number of the heating coils (2) is multiple, and the heating coils (2) are correspondingly arranged in the mounting grooves (11) one by one;

at least two of the plurality of heating coils (2) have different numbers of coil turns; and/or the distances between adjacent turns of at least two of the heating coils (2) are different.

2. A tire vulcanizing mold according to claim 1, characterized in that said mounting groove (11) is an annular groove structure, and a plurality of said mounting grooves (11) are arranged at intervals along the mold opening direction of said mold body (1).

3. The tire vulcanizing mold according to claim 1, wherein the mounting groove (11) is of a spiral groove structure, a plurality of the mounting grooves (11) are arranged at intervals along the mold opening direction of the mold body (1), and the heating coil (2) is arranged in the mounting groove (11) along the spiral direction of the mounting groove (11).

4. A tyre vulcanisation mould according to claim 3, wherein at least two mounting grooves (11) of said plurality of mounting grooves (11) have a different pitch.

5. The tire vulcanizing mold according to claim 1, wherein a plurality of steps are formed on the peripheral side wall of the mold body (1) along the mold opening direction and are gradually close to the central axis of the mold body (1), and at least one mounting groove (11) is arranged on the peripheral side wall of each step; or the like, or, alternatively,

the die is characterized in that a conical surface which is close to the central shaft of the die body (1) gradually along the die opening direction is formed on the peripheral side wall of the die body (1), and the mounting grooves (11) are formed in the conical surface.

6. A tire vulcanizing mold according to any one of claims 1 to 5, characterized in that the mold body (1) is an open-top segmented mold, the mold body (1) comprises a guide ring (12), a base (13), a block (14) and an upper cover (15), the base (13) is arranged at the lower end of the guide ring (12), the upper cover (15) is slidably connected at the upper end of the guide ring (12), the block (14) is slidably arranged in the guide ring (12), and a plurality of mounting grooves (11) are arranged on the outer peripheral side wall of the guide ring (12).

7. A tire vulcanizing mold according to any one of claims 1 to 5, characterized in that the mold body (1) is a lower-opening segmented mold, the mold body (1) comprises a guide ring (12), a base (13), blocks (14) and an upper cover (15), the base (13) is slidably connected to the lower end of the guide ring (12), the upper cover (15) is detachably provided on the upper end of the guide ring (12), the blocks (14) are slidably provided in the guide ring (12), and a plurality of mounting grooves (11) are provided on the outer peripheral side wall of the guide ring (12).

8. A tire vulcanizing mold according to any one of claims 1 to 5, characterized in that the mold body (1) is a two-half segmented mold, the mold body (1) comprises an upper mold part and a lower mold part which are oppositely arranged, the upper mold part comprises an upper guide ring (161), an upper cover (15) and upper blocks (163), the upper cover (15) is arranged at the upper end of the upper guide ring (161), and the upper blocks (163) are slidably arranged in the upper guide ring (161); the lower die part comprises a lower guide ring (171), a base (13) and lower pattern blocks (173), the base (13) is arranged at the lower end of the lower guide ring (171), the lower pattern blocks (173) are arranged in the lower guide ring (171) in a sliding mode, at least one of the installation grooves (11) is arranged on the peripheral side wall of the upper guide ring (161), and the rest installation grooves (11) are arranged on the peripheral side wall of the lower guide ring (171).

9. A tire vulcanizing mold according to any one of claims 1 to 5, characterized in that said mold body (1) is a mold half, said mold body (1) comprising an upper mold (16) and a lower mold (17) which are disposed oppositely, at least one of said mounting grooves (11) being provided on a peripheral side wall of said upper mold (16), the remaining mounting grooves (11) being provided on a peripheral side wall of said lower mold (17).