Printing nozzle device

Abstract

The utility model belongs to the technical field of building 3D printing, and discloses a printing spray head device which comprises a temporary storage seat, a conversion disc and a plurality of spray heads, the conversion disc is rotationally connected to the temporary storage seat, a temporary storage cavity is formed in the temporary storage seat, one end of the temporary storage cavity is communicated with an external feeding pipe, and a feeding opening is formed in the other end of the temporary storage cavity; a plurality of connecting channels which are communicated in the first direction are arranged on a conversion disc, a plurality of spray heads are connected, the conversion disc is rotated, the different connecting channels can be in butt joint with and communicate with a feeding port, and the replacement efficiency is improved. On the basis, due to the fact that a temporary storage cavity is formed in a temporary storage base, materials conveyed by an external feeding pipeline are temporarily stored in the temporary storage cavity firstly, and then the materials are conveyed into the temporary storage cavity; printing interruption caused by unstable feeding and the like is avoided, in addition, the heating element is arranged in the temporary storage cavity of the temporary storage base, heating can be conducted in time before the spray head sprays the materials, the structure of the spray head is simplified, the rotating load of the conversion disc is reduced, and it is ensured that the nozzle can keep stable shape and precision for a long time.

Description

TECHNICAL FIELD

[0001] The utility model relates to building 3D printing technical field especially, relate to a printing nozzle device. BACKGROUND

[0002] Building 3D printing is similar to ordinary printer working principle, building 3D printer is loaded with concrete, mortar, plastic and other building materials, is connected after with computer, through the material of one layer and another layer is added in succession, finally the building design blueprint on computer becomes real object, and the building 3D printer on market is mostly fixed nozzle, can only be adjusted 3D printing forming effect through changing extrusion speed, nozzle moving speed, inclination angle etc. when 3D printing, manually replacing nozzle efficiency is low.

[0003] For the above problems, the prior art designs a printing nozzle device, including switchable nozzle and feed unit, wherein the feed unit is arranged above the switchable nozzle, the switchable nozzle includes a rotating disc rotatable around an axis and at least one nozzle connecting part, each nozzle connecting part is provided below with a nozzle of different size, the nozzle is switched by rotating the rotating disc, and the replacement efficiency is improved.

[0004] However, in order to avoid the phenomenon of solidification or crystallization of building materials, the prior art sets a heating element on the switchable nozzle, which makes the structure of the switchable nozzle complex, the load of the rotating disc increases, and the long-term thermal stress may change the shape of the nozzle, affecting the precision and shape of the jet. UTILITY MODEL CONTENTS

[0005] The utility model aims at providing a printing nozzle device, which can simplify the nozzle structure and improve the jet quality on the basis of improving the replacement efficiency of the nozzle.

[0006] To achieve this purpose, the utility model adopts the following technical solutions:

[0007] The printing nozzle device comprises:

[0008] The buffer seat is provided with a buffer cavity, which is configured to carry a heating element, one end of the buffer cavity is communicated with an external feed pipe, and the other end is provided with a feeding port;

[0009] The conversion disc is rotationally connected to the buffer seat, and the conversion disc is provided with a plurality of connection channels, which can be sequentially communicated with the feeding port when the conversion disc rotates relative to the buffer seat.

[0010] A plurality of spray heads are connected to the conversion disc, and each of the spray heads is provided with a spray channel.

[0011] Preferably, the buffer cavity comprises a first buffer cavity and a second buffer cavity connected to each other, one end of the first buffer cavity is connected to the external feeding pipeline, and the inner wall surface of the second buffer cavity gradually extends to the feeding port in the direction away from the first buffer cavity.

[0012] Preferably, a temperature sensor is arranged in the second buffer cavity, and the temperature sensor is configured to detect the temperature in the second buffer cavity.

[0013] Preferably, the spray head is provided with an external thread at the end away from the spray port, and a threaded hole matched with the external thread is arranged on the inner wall surface of the connecting channel.

[0014] Preferably, the outer wall of the spray head is provided with a stop protruding ring, and the stop protruding ring abuts against the conversion disc.

[0015] Preferably, the spray head is provided with three spray heads, which are a first spray head, a second spray head and a third spray head, the spray ports of the first spray head and the second spray head are circular, the diameter of the spray port of the first spray head is greater than that of the spray port of the second spray head, and the spray port of the third spray head is rectangular.

[0016] Preferably, one of the buffer seat and the conversion disc is provided with a protruding head, and the other is provided with a plurality of grooves matched with the protruding head, the plurality of grooves and the plurality of connecting channels correspond one by one, and when the protruding head is inserted into one of the grooves, the connecting channel corresponding to the groove is connected to the feeding port.

[0017] Preferably, the outer wall of the buffer seat is provided with a first positioning mark at the end facing the conversion disc, the conversion disc is provided with a plurality of second positioning marks, the plurality of second positioning marks and the plurality of spray heads correspond one by one, and when the first positioning mark is opposite to one of the second positioning marks, the spray channel of the spray head corresponding to the second positioning mark is connected to the buffer cavity.

[0018] Preferably, the outer surface of the buffer seat is provided with a heat insulation layer.

[0019] Preferably, the conversion disc is provided with a rotating part, and the rotating part protrudes from the outer side wall of the conversion disc.

[0020] The beneficial effects of the utility model are as follows:

[0021] The utility model provides a printing nozzle device, through with the conversion disc rotation connects in the buffer seat, and is equipped with the buffer cavity on the buffer seat, the buffer cavity one end is connected with the outside feed pipe, sets up the feeding port in the other end, is equipped with a plurality of along the first direction through's connection channel on the conversion disc, and is connected with a plurality of nozzles, when needing to switch the nozzle of different size and / or shape to realize different printing effect, need not manual disassembly nozzle again installation etc. Complex operation, only need to rotate the conversion disc, can make different connection channel and feeding port butt joint and intercommunication, and then make corresponding nozzle participate in work, realize quick switching nozzle function, greatly simplified the nozzle replacement this operation procedure, improve the replacement efficiency, on this basis, because the buffer cavity is equipped with in the buffer seat, make the material that the outside feed line delivers can enter the buffer cavity first and store temporarily, avoided the printing interruption due to the unstable feeding etc. Situation, effectively guarantee the continuity of material supply, ensure that the printing work can smoothly carry out, and, set up the heating element in the buffer cavity of the buffer seat, can heat in time before the nozzle sprays the material, make the structure of nozzle itself be simplified, reduce the load of the conversion disc rotation, eliminate the long-term thermal stress effect on the nozzle hidden danger, ensure that the spout can keep stable shape and precision for a long time. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is the first structure schematic diagram of printing nozzle device that the utility model embodiment describes;

[0023] Figure 2 It is the second structure schematic diagram of printing nozzle device that the utility model embodiment describes.

[0024] In the drawing:

[0025] 1, buffer seat;10, buffer cavity;100, feeding port;101, first buffer cavity;102, second buffer cavity;11, first positioning mark;

[0026] 2, conversion disc;20, connection channel;21, second positioning mark;

[0027] 3, nozzle;301, spout. DETAILED DESCRIPTION

[0028] The embodiments of the utility model are described in detail below, the example of embodiment is shown in the drawing, wherein the same or similar signs show the same or similar parts or the parts with the same or similar function all along. The embodiment described below through the reference drawing is exemplary, and it is used to explain the utility model, and it can not be understood as the limitation of the utility model.

[0029] In the description of the utility model, unless another definite provision and limitation, the term "connect", "connection", "fixed" should be broad sense understanding, for example, can be fixed connection, also can be detachable connection, can be mechanical connection, also can be electrical connection, can be direct connection, also can be indirectly connected through the intermediate medium, can be two element internal communication or two element's mutual action relationship. For ordinary skilled in the art, the above-mentioned term can be understood according to the specific meaning in the utility model.

[0030] In the description of the utility model, unless another definite provision and limitation, the first feature is "on" or "under" the second feature can include the first feature and the second feature direct contact, also can include the first feature and the second feature is not direct contact but is through the contact between other features between them. Moreover, the first feature is "on", "above" and "on" the second feature includes the first feature is directly above and obliquely above the second feature, or just indicates that the first feature is higher than the second feature in horizontal height. The first feature is "under", "below" and "under" the second feature includes the first feature is directly below and obliquely below the second feature, or just indicates that the first feature is less than the second feature in horizontal height.

[0031] The technical scheme of the utility model is further illustrated below by specific embodiments in conjunction with the drawings.

[0032] As Figures 1-2 shown, the utility model provides a kind of printing head device, including buffer seat 1, conversion disc 2 and multiple nozzle 3, buffer seat 1 is provided with buffer cavity 10, buffer cavity 10 is configured as bearing heating element, buffer cavity 10 one end is communicated with external feed line, and the other end is provided with feeding port 100;Conversion disc 2 is rotatably connected to buffer seat 1, conversion disc 2 is provided with multiple connection channels 20, and multiple connection channels 20 can be sequentially communicated with feeding port 100 when conversion disc 2 rotates relative to buffer seat 1;Multiple nozzle 3 are connected to conversion disc 2, and nozzle 3 is provided with injection channel 30, multiple injection channels 30 and multiple connection channels 20 one-to-one correspondence and communicate, and the one end of injection channel 30 is provided with nozzle 301, away from connection channel 20, multiple nozzle 301 size and / or shape are different in pairs.

[0033] The utility model discloses a conversion disc 2 is connected in rotation in the buffer seat 1, and is equipped with the buffer cavity 10 on the buffer seat 1, one end of buffer cavity 10 is communicated with the external feed pipe, and the other end is provided with the feeding port 100, and is equipped with a plurality of connecting channels 20 along the first direction through on the conversion disc 2, and is connected with a plurality of spray heads 3, when needing to switch the spray head 3 of different size and / or shape to realize different printing effect, without manually disassembling spray head 3 and installing again and other complex operation, only need to rotate the conversion disc 2, can make different connecting channels 20 with the feeding port 100 butt joint and intercommunication, and then make corresponding spray head 3 participate in work, realize the function of quick switching spray head 3, greatly simplify the operation process of spray head 3 replacement, improve the replacement efficiency, on this basis, because the buffer cavity 10 is equipped with the buffer seat 1, the material that the external feed line delivers can first enter the buffer cavity 10 and store temporarily, avoid the printing interruption caused by unstable feeding and the like, effectively guarantee the continuity of material supply, ensure that printing work can smoothly carry out, and heating element is arranged in the buffer cavity 10 of buffer seat 1, can heat in time before spray head 3 sprays material, make the structure of spray head 3 simplify, reduce the load of conversion disc 2 rotation, eliminate the hidden danger that long-term thermal stress acts on spray head 3, ensure that the spout 301 can keep stable shape and precision for a long time.

[0034] In the embodiment, the buffer seat 1 and the conversion disc 2 are both cylindrical, the conversion disc 2 is provided with a mounting hole for mounting a ball bearing, the outer ring of the ball bearing is in interference fit with the mounting hole, so that the ball bearing can be firmly mounted on the conversion disc 2, the inner ring of the ball bearing is in interference fit with the outer ring of the buffer seat 1, so that the buffer seat 1 is fixedly mounted in the ball bearing on the conversion disc 2, and the conversion disc 2 is rotatably connected with the buffer seat 1 through the ball bearing.

[0035] In the embodiment, the heating element is a heating pipe, the inner wall of the buffer cavity 10 is provided with a mounting bracket, and the heating pipe is fixed on the bracket. In order to prevent the heating pipe from directly contacting the printing material, a layer of ceramic fiber with high temperature resistance and good heat conduction is wrapped outside the heating pipe, which can ensure heat transfer and protect the printing material from pollution or damage.

[0036] In other embodiments, the heating element can also be a heating sheet attached to the inner wall of the buffer cavity 10. It should be noted that the heating pipe and the heating sheet are both conventional electrical elements in the art, and their circuit connection relationship and working method are conventional settings, which will not be described here.

[0037] Specifically, as Figure 2As shown, the buffer cavity 10 includes a first buffer cavity 101 and a second buffer cavity 102 in communication, the first buffer cavity 101 is communicated with the external feeding pipeline at one end, and the inner wall surface of the second buffer cavity 102 gradually extends to the feeding port 100 in the direction away from the first buffer cavity 101. The external feeding pipeline first delivers the printing material into the first buffer cavity 101, and the first buffer cavity 101 plays a role of preliminarily receiving and buffering the printing material, can accommodate a certain amount of printing material, so that the feeding process is more stable, and the influence of the subsequent printing nozzle 3 caused by the instantaneous flow fluctuation of the feeding process and the like is avoided; with the inner wall surface of the second buffer cavity 102 gradually extending to the feeding port 100, the printing material can flow more orderly and centrally to the feeding port 100, the directionality and accuracy of the printing material delivery are improved, and in the gradually narrowing space, the pressure of the printing material will gradually increase, which is more beneficial to extruding the material to the feeding port 100, prepares for the subsequent smooth passing of the feeding port 100 into the connecting channel 20 on the conversion disc 2, and guarantees the continuity and accuracy of the material supply of the entire printing nozzle device during the printing work.

[0038] More specifically, the second buffer cavity 102 is provided with a temperature sensor, and the temperature sensor is configured to detect the temperature in the second buffer cavity 102. By continuously detecting the temperature in the second buffer cavity 102 through the temperature sensor, the operator can know the current temperature state of the printing material, and when it is detected that the temperature is lower than the required temperature value of the printing material, the power of the heating element in the buffer cavity 10 can be increased to make the temperature rise to the appropriate interval, ensure that the material maintains good fluidity, make the printing lines uniform and continuous, and avoid problems such as nozzle 3 blockage or printing interruption caused by poor material fluidity; on the contrary, if the temperature is too high and exceeds the upper limit that the material can withstand, the power of the heating element can be appropriately reduced to prevent the material from decomposing and carbonizing due to overheating, which affects the printing quality and causes damage to the nozzle 3. It should be noted that the temperature sensor is a conventional electrical element in the art, and its circuit connection relationship and working method are conventional settings, which will not be described here.

[0039] Specifically, the end of the spray head 3 away from the nozzle 301 is provided with an external thread, and the inner wall surface of the connecting channel 20 is provided with a threaded hole matched with the external thread. The threaded connection structure is tight, and can withstand multiple installation, disassembly and various stresses in daily work during long-term use, thereby realizing reliable connection of the spray head 3 and the conversion disc 2; and this threaded connection mode greatly improves the convenience and flexibility of the spray head 3 in the installation and disassembly link. When installing, the operator only needs to manually rotate the external thread of the spray head 3 to the threaded hole of the connecting channel 20, and the assembly can be easily completed, without the need for complex tools and low operation difficulty, effectively improving the assembly efficiency of the device; when disassembling, the spray head 3 can also be quickly rotated out, whether it is maintenance, cleaning or replacement of the spray head 3 to adapt to different printing needs, which can be quickly realized, greatly reducing the equipment downtime caused by the problem of the spray head 3, and effectively guaranteeing the continuity and efficiency of the printing work.

[0040] More specifically, the outer wall of the spray head 3 is provided with a stop protruding ring, which abuts against the conversion disc 2. When the spray head 3 is connected to the connecting channel 20 on the conversion disc 2 by threads or other means, the stop protruding ring abuts against the conversion disc 2, which can clearly limit the depth of the spray head 3 rotating in, ensuring that its spray channel 30 accurately communicates with the corresponding connecting channel 20, avoiding problems such as poor channel communication, material transport obstruction or poor sealing caused by inconsistent installation depth, thereby ensuring that the printing material can flow smoothly from the connecting channel 20 into the spray channel 30 of the spray head 3, and be sprayed from the nozzle 301 as expected for printing operation; secondly, the stop protruding ring abuts against the conversion disc 2, which provides an additional stable support point for the spray head 3, which cooperates with the threaded connection and other means to further strengthen the connection stability between the spray head 3 and the conversion disc 2, effectively preventing the spray head 3 from loosening or even detaching from the connecting channel 20 under the action of vibration, so that the spray head 3 can always be stably maintained in the correct working position, ensuring the reliability of material transport and spraying during the entire printing process; and the stop protruding ring can also seal the gap between the spray head 3 and the connecting channel 20.

[0041] Specifically, as Figure 1As shown, the spray head 3 is provided with three, three spray heads 3 are first, second and third spray head, the first and second spray head nozzle 301 are circular, the diameter of the first spray head nozzle 301 is greater than the diameter of the second spray head nozzle 301, the third spray head nozzle 301 is rectangular. The first spray head larger diameter circular nozzle 301 can quickly cover a large area, build a rough line and a large block structure, improve the printing efficiency, and is suitable for large base printing; the second spray head smaller diameter circular nozzle 301 can realize high-precision printing, create fine texture and details, and meet the high-quality surface requirements; the third spray head rectangular nozzle 301 can print flat strip-shaped patterns, enrich the design diversity, and the three cooperate with each other, greatly expanding the printing function and application range of the device.

[0042] Specifically, on the buffer seat 1 and the conversion disc 2, one is provided with a convex head, and the other is provided with a plurality of grooves matched with the convex head, the plurality of grooves and the plurality of connecting channels 20 are one-to-one corresponding, when the convex head is inserted into a groove, the connecting channel 20 corresponding to the groove is communicated with the feeding port 100. When the convex head is inserted into a specific groove, not only can the corresponding connecting channel 20 and the feeding port 100 be accurately communicated, so that the transmission path of the printing material can be accurately determined, but also during the rotation of the conversion disc 2, this positioning mode can strictly limit the rotation angle and position of the conversion disc 2, so that each groove corresponds to a unique connecting channel 20 and a specific working state, effectively avoiding the problems of channel misplacement or abnormal communication caused by the rotation deviation of the conversion disc 2, so that the whole printing spray head device always maintains high accuracy and stability during the switching of different spray heads 3 and the material conveying process, and provides a solid and reliable structural foundation for high-quality and high-precision printing work.

[0043] In this embodiment, the buffer seat 1 is provided with a convex head, and the conversion disc 2 is provided with a plurality of grooves.

[0044] In other embodiments, the convex head can be provided on the conversion disc 2, and the plurality of grooves can be provided on the buffer seat 1.

[0045] Specifically, as Figure 1As shown, the outer wall of the buffer seat 1 is provided with a first positioning mark 11 at one end facing the conversion disc 2, and the conversion disc 2 is provided with a plurality of second positioning marks 21, which correspond to the plurality of nozzles 3 one by one. When the first positioning mark 11 is opposite to one second positioning mark 21, the spray channel 30 of the nozzle 3 corresponding to the second positioning mark 21 is communicated with the buffer cavity 10. When it is necessary to switch to a specific nozzle 3 for printing, the operator can quickly rotate the conversion disc 2 to the target position according to the two positioning marks, so as to realize the communication of the corresponding nozzle 3 and the buffer cavity 10. This convenient operation mode speeds up the operation speed of nozzle 3 switching, material conveying channel adjustment and the like in the printing task, and further improves the efficiency of the entire printing work.

[0046] In this embodiment, the first positioning mark 11 and the second positioning mark 21 are diagonal marks coated on the outer wall of the buffer seat 1 and the outer wall of the conversion disc 2. When the operator needs to switch the nozzle 3, the operator looks for the diagonal mark on the conversion disc 2 that is aligned with the diagonal mark on the buffer seat 1. The line direction of the diagonal mark guides the operator to quickly focus on the corresponding mark position, and intuitively judges whether the conversion disc 2 has been rotated to the correct angle to realize the communication of the corresponding nozzle 3 and the buffer cavity 10, thereby reducing the time for finding and aligning the mark during operation.

[0047] Specifically, the outer surface of the buffer seat 1 is provided with a heat insulation layer. In the printing process, the buffer cavity 10 in the buffer seat 1 usually needs to maintain a specific temperature environment to ensure that the printing material maintains appropriate fluidity. The heat insulation layer can effectively block the influence of the external environment temperature and reduce the heat transfer. When the external temperature is low, it can prevent the heat in the buffer cavity 10 from dissipating too quickly, avoid the viscosity of the printing material increasing and the fluidity of the printing material deteriorating due to the decrease of the temperature, and further affect the normal jet printing. When the external temperature is high, the heat insulation layer can also prevent the external heat from entering and prevent the temperature in the buffer cavity 10 from being too high, so as to avoid the change of the material performance or the deterioration of the material, and ensure the relative stability of the temperature in the buffer cavity 10, which is helpful to maintain the consistency of the printing quality.

[0048] In this embodiment, the heat insulation layer is a vacuum heat insulation plate attached to the outer surface of the buffer seat 1, which uses the vacuum environment inside to block the heat conduction. It should be noted that the vacuum heat insulation plate belongs to mature technology in the art.

[0049] Specifically, the conversion disc 2 is provided with a rotating part which protrudes from the outer side wall of the conversion disc 2. The protruding design of the rotating part provides a convenient force point for the operator. When it is necessary to rotate the conversion disc 2 to switch the nozzle 3, adjust the communication state of the connecting channel 20 and the feeding port 100 of the buffer seat 1, and the like, the operator can directly hold or act on the protruding rotating part with a tool to easily apply a rotating torque, so that the conversion disc 2 can be smoothly rotated, and the operation efficiency is improved.

[0050] In this embodiment, the rotating part is a rod-shaped structure protruding from the outer side wall of the conversion disc 2, providing an easy-to-grip part for the operator, facilitating one-handed or two-handed operation.

[0051] Obviously, the above embodiments of the present application are merely examples for clearly illustrating the present application, and are not intended to limit the implementation modes of the present application. For those skilled in the art, other different forms of changes or modifications can be made on the basis of the above description. Here, it is not necessary and impossible to exhaust all the implementation modes. Any modification, equivalent replacement and improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A print head apparatus, characterized by, The utility model relates to a kind of heating device, including: Buffer seat (1), the buffer seat (1) is provided with buffer cavity (10), the buffer cavity (10) is configured to carry heating element, the buffer cavity (10) one end is communicated with external feed line, the other end is provided with feeding port (100); Conversion disc (2), the conversion disc (2) is rotatably connected to the buffer seat (1), the conversion disc (2) is provided with multiple connection channels (20), when the conversion disc (2) rotates relative to the buffer seat (1), multiple connection channels (20) can be sequentially communicated with feeding port (100); Multiple spray heads (3), multiple spray heads (3) are connected to the conversion disc (2), the spray head (3) is provided with injection channel (30), multiple injection channels (30) and multiple connection channels (20) are one-to-one correspondence and communicated, the injection channel (30) is provided with spout (301) away from one end of the connection channel (20), the size and / or shape of multiple spouts (301) are different from each other.

2. The print head apparatus of claim 1, wherein, The buffer cavity (10) includes the first buffer cavity (101) and the second buffer cavity (102) connected, the first buffer cavity (101) one end is communicated with external feed line, along the direction away from the first buffer cavity (101), the inner wall surface of the second buffer cavity (102) gradually extends to the feeding port (100).

3. The print head arrangement of claim 2, wherein, The second buffer cavity (102) is provided with a temperature sensor, and the temperature sensor is configured to detect the temperature in the second buffer cavity (102).

4. The print head apparatus of claim 1, wherein, The spray head (3) is provided with an external thread at one end away from the spout (301), and a threaded hole matched with the external thread is arranged on the inner wall surface of the connection channel (20).

5. The print head arrangement of claim 4, wherein, The outer wall of the spray head (3) is provided with a stop protruding ring, which abuts against the conversion disc (2).

6. The print head apparatus of claim 1, wherein, The spray head (3) is provided with three, three spray heads (3) are first spray head, second spray head and third spray head, the spout (301) of the first spray head and the second spray head is circular, the diameter of the spout (301) of the first spray head is greater than the diameter of the spout (301) of the second spray head, and the spout (301) of the third spray head is rectangular.

7. The print head apparatus of claim 1, wherein The buffer seat (1) and the conversion disc (2) are provided with a protrusion and a plurality of grooves matched with the protrusion, respectively, and the plurality of grooves and the plurality of connection channels (20) are one-to-one correspondence, when the protrusion is inserted into one of the grooves, the connection channel (20) corresponding to the groove is communicated with the feeding port (100).

8. The print head apparatus of claim 1, wherein, An outer wall of the buffer seat (1) is provided with a first positioning mark (11) at one end facing the conversion disc (2), the conversion disc (2) is provided with a plurality of second positioning marks (21), the plurality of second positioning marks (21) and the plurality of nozzles (3) are in one-to-one correspondence, when the first positioning mark (11) is opposite to one of the second positioning marks (21), the spray channel (30) of the nozzle (3) corresponding to the second positioning mark (21) is communicated with the buffer cavity (10).

9. The printing head apparatus according to claim 1, wherein The buffer seat (1) is provided with a heat insulation layer on an outer surface.

10. The printing head device according to any one of claims 1 to 9, wherein The conversion disc (2) is provided with a rotating part which protrudes from an outer side wall of the conversion disc (2).

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