Bristles imbedding device for toothbrush production
By setting a limiting component on the bristle implantation block, the problem of nylon bristles slipping off during the bristle implantation process was solved, achieving stability and continuity in the bristle implantation process and avoiding material waste.
Patent Information
- Application Number
- CN202511478117.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-16
- Publication Date
- 2025-11-14
AI Technical Summary
In existing technologies, nylon bristles are prone to slipping off the feed trough during the bristle implantation process, leading to instability in the bristle implantation process.
A limiting component is set on the bristle-planting block. The movement of the limiting component is controlled by the ejector pin to close the feed chute to prevent the bristles from slipping off. The feed chute is automatically opened after the bristle-planting is completed so that the material can continue to be supplied.
It effectively prevents the bristles from slipping during the bristle implantation process, ensuring the stability and continuity of the process and avoiding material waste.
Smart Images

Figure CN120938207A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of toothbrush processing equipment technology, and in particular to a bristle insertion device for toothbrush production. Background Technology
[0002] A toothbrush is a cleaning product with a handle. Toothbrush bristles are made of either natural boar bristles or nylon filaments. Natural boar bristles are better at cleaning and absorbing toothpaste than nylon filaments, but they also have drawbacks. They are more absorbent and dry very slowly, making them more prone to mold growth. Nylon filaments are fine and soft, able to clean between teeth, and have good elasticity, providing a better massage effect. In addition, their wear-resistant and non-absorbent properties make them the preferred material for toothbrush bristles.
[0003] In existing technology, when manufacturing toothbrushes, the toothbrush handle is first processed using a toothbrush mold, and then the bristles are inserted into the bristle holes of the handle using a bristle implantation machine. In existing technology, the bristle implantation machine uses a toothbrush insertion device during the bristle implantation process. After the bristles are fed from the feed trough to the device, a pin on the device pushes the bristles into the bristle holes. However, in existing technology, the nylon filaments used during the bristle implantation process are prone to slipping off the feed trough after feeding. Summary of the Invention
[0004] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a bristle insertion device for toothbrush production. By using a limiting component set on the bristle insertion block, the phenomenon of bristles slipping off the feed trough can be reduced.
[0005] (II) Technical Solution To achieve the above objectives, this application provides a bristle insertion device for toothbrush production, mounted on a bristle implantation machine. It includes a mounting base detachably and fixedly connected to the bristle implantation machine. A through-type moving channel is formed in the middle of the mounting base. A bristle implantation block is slidably connected to the moving channel. A bristle implantation hole is formed along the length direction inside the bristle implantation block, and a pin is slidably connected within the bristle implantation hole. A feeding groove is formed on one side wall of the outer side of the bristle implantation block, and the feeding groove communicates with the bristle implantation hole. One end of the bristle implantation hole forms a bristle implantation nozzle. A limiting hole is formed on the tufting block and on one side of the tufting hole. The limiting hole is parallel to the tufting hole and communicates with the feed groove. An elongated groove is formed between the limiting hole and the tufting hole. A limiting component is provided in the limiting hole. One end of the limiting component can enter the feed groove through the limiting hole. When the ejector pin moves towards the tufting nozzle, the limiting component limits the feed groove. When the ejector pin moves away from the tufting nozzle, the ejector pin controls the limiting component to disengage from the feed groove.
[0006] Preferably, the limiting hole includes a first hole segment and a second hole segment, the first hole segment is located at the end away from the tufting nozzle, and the second hole segment is located at the end closer to the tufting nozzle; the diameter of the first hole segment is larger than the diameter of the second hole segment; a plug is threadedly connected to the end of the first hole segment away from the second hole segment; the long groove is connected to the first hole segment.
[0007] Preferably, the limiting assembly includes a mounting post, a compression spring, a connecting rod, a linkage block, and a limiting block; the mounting post and the compression spring are slidably connected within the first hole section, one end of the compression spring abuts against the mounting post, and the other end abuts against the plug; the connecting rod slides through the second hole section, one end of the connecting rod is fixedly connected to the mounting post, and the other end is fixedly connected to the limiting block; the linkage block is located within the elongated groove and is detachably and fixedly connected to the mounting post, and the linkage block abuts against the side wall of the ejector pin.
[0008] Preferably, the long groove includes a first groove and a second groove, which are interconnected, and the first groove is shorter than the second groove. The first groove is located on the side near the first hole segment, and the second groove is located on the side near the tufting hole. One end of the second groove extends through the end of the tufting block away from the tufting nozzle along its length. An abutment block is fixed to the side wall of the ejector pin. The abutment block is fitted into the second groove and is located on the side of the linkage block near the tufting nozzle. When the ejector pin moves away from the tufting nozzle, the abutment block abuts against the linkage block and drives the linkage block to move away from the tufting nozzle. When the ejector pin moves to its maximum distance, the linkage block abuts against the end of the first groove away from the tufting nozzle.
[0009] Preferably, the tufting block has an installation hole on the side near the feed trough, and the installation hole is connected to the first hole segment; the installation hole is located within the area of the first trough body, the mounting column has a through first fixing hole, and the linkage block has a second fixing hole. When the linkage block is located at one end of the first trough body, the first fixing hole, the second fixing hole and the installation hole are concentric; a fixing screw is threaded into the first fixing hole and the second fixing hole.
[0010] Preferably, the second hole segment has an opening at one end near the tufting nozzle and on the side opposite to the tufting hole, and an arc-shaped side is formed on the side near the tufting hole; at the end near the tufting nozzle, the distance between the arc-shaped side and the tufting hole gradually decreases. The limiting block always remains within the range of the opening when it slides; the limiting block is rectangular, and a connecting body is formed at the end of the limiting block away from the tufting nozzle. An arc-shaped surface is formed on the side of the connecting body near the arc-shaped side. When the limiting block closes the feed chute, the arc-shaped surface and the arc-shaped side fit together; the connecting rod is made of elastic material.
[0011] Preferably, an arc-shaped groove is formed at one end of the limiting block near the hair implantation hole, and when the limiting block closes the feed chute, the arc-shaped groove is close to the inner wall of the hair implantation hole.
[0012] Preferably, the tufting block has a feeding hole on one side away from the feeding groove, the feeding hole is perpendicular to the length direction of the tufting hole and communicates with the tufting hole; the feeding hole is located between the long groove and the tufting nozzle.
[0013] Preferably, the tufting nozzle is V-shaped, with an opening at the tip and guide plates on both sides of the opening.
[0014] (III) Beneficial Effects This invention provides a bristle insertion device for compression production. A limiting component mounted on the bristle-planting block controls the operation of the limiting component via a push pin. Each time bristle material is placed into the feed trough and aligned with the bristle-planting hole, the limiting component closes and limits the feed trough, preventing the bristle material from moving outwards and falling during the bristle-planting process. After one bristle material has been planted, the limiting component retracts from the feed trough, opening it for further material feeding. This limiting component effectively limits and blocks material from entering the feed trough without hindering normal material supply. Attached Figure Description
[0015] Figure 1 This is a schematic diagram of the structure of a brush inserting device for compression production according to the present invention; Figure 2 This is a cross-sectional view highlighting the hair-embedded block in this invention; Figure 3 for Figure 1 Enlarged view of the A-structure in the middle; Figure 4 This is a schematic diagram of the limiting block of the present invention.
[0016] Marked in the attached diagram: 100. Mounting base; 110. Moving channel; 200. Embedding block; 210. Embedding hole; 220. Feed trough; 230. Embedding nozzle; 231. Opening; 232. Guide plate; 240. Limiting hole; 241. First hole section; 242. Second hole section; 243. Opening; 244. Arc-shaped side; 250. Long groove; 251. First groove body; 252. Second groove body; 260. Plug; 270. Mounting hole; 280. Feed hole; 300. Ejector pin; 310. Abutment block; 400. Limiting component; 410. Mounting post; 411. First fixing hole; 420. Compression spring; 430. Connecting rod; 440. Linkage block; 441. Second fixing hole; 450. Limiting block; 460. Fixing screw; 470. Connector; 471. Arc-shaped surface. Detailed Implementation
[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0018] Example This invention provides a bristle insertion device for toothbrush production, see [link to related document]. Figures 1-4 Installed on a hair implantation machine, including a mounting base 100 that is detachably and fixedly connected to the hair implantation machine. A through moving channel 110 is formed in the middle of the mounting base 100. A hair implantation block 200 is slidably connected to the moving channel 110. A hair implantation hole 210 is opened in the hair implantation block 200 along the length direction. The length direction of the hair implantation hole 210 is the same as the moving direction of the hair implantation block 200.
[0019] A pin 300 is slidably connected within the bristle implantation hole 210; a feed groove 220 is provided on one side wall of the outer side of the bristle implantation block 200, which connects to the bristle implantation hole 210; during bristle implantation, the bristle implantation machine puts the bristle material to be implanted into the feed groove 220. One end of the bristle implantation hole 210 forms a bristle implantation nozzle 230. During bristle implantation, the drive device controls the bristle implantation block 200 to approach the toothbrush handle, and controls the pin 300 to move relative to the bristle implantation block 200, so that the pin 300 carries the bristle material out of the bristle implantation nozzle 230 and into the toothbrush implantation hole, completing one bristle implantation operation.
[0020] A limiting hole 240 is provided on the tufting block 200 and on one side of the tufting hole 210. The limiting hole 240 is parallel to the tufting hole 210 and connects to the feed groove 220. An elongated groove 250 is provided between the limiting hole 240 and the tufting hole 210. A limiting component 400 is provided in the limiting hole 240. One end of the limiting component 400 can enter the feed groove 220 through the limiting hole 240. When the ejector pin 300 moves towards the end closer to the tufting nozzle 230, the limiting component 400 limits the feed groove 220. When the ejector pin 300 moves away from the end away from the tufting nozzle 230, the ejector pin 300 controls the limiting component 400 to disengage from the feed groove 220. By using the limiting component 400, during operation, each time bristle material is placed into the feed trough 220 and aligned with the bristle insertion hole 210, the limiting component 400 closes and limits the feed trough 220, thereby preventing the bristle material from moving outwards during the bristle insertion process. After the bristle insertion of one bristle material is completed, the limiting component 400 retracts from the feed trough 220, allowing the feed trough 220 to open again and allowing material to be fed in again. This limiting component 400 effectively limits and blocks material in the feed trough 220 without hindering normal material feeding through it.
[0021] The limiting hole 240 includes a first hole segment 241 and a second hole segment 242. The first hole segment 241 is located at the end away from the tufting nozzle 230, and the second hole segment 242 is located at the end closer to the tufting nozzle 230. The diameter of the first hole segment 241 is larger than the diameter of the second hole segment 242. A plug 260 is threadedly connected to the end of the first hole segment 241 away from the second hole segment 242. The long groove 250 communicates with the first hole segment 241. During installation, the limiting component 400 is installed from the end of the first hole segment 241 away from the second hole segment 242, and then the port is sealed by the plug 260.
[0022] Specifically, the limiting component 400 includes a mounting post 410, a compression spring 420, a connecting rod 430, a linkage block 440, and a limiting block 450.
[0023] The mounting post 410 and the compression spring 420 are slidably connected within the first hole section 241. The mounting post 410 is located at the end closer to the second hole section 242, and the diameter of the mounting post 410 is larger than the diameter of the second hole section 242. The compression spring 420 is located at the end away from the second hole section 242.
[0024] One end of the compression spring 420 abuts against the mounting post 410, and the other end abuts against the plug 260. The compression spring 420 is always kept in a compressed state, and the compression spring 420 provides elastic force to the mounting post 410, so that the mounting post 410 can slide towards the end closer to the tufting nozzle 230 without restriction.
[0025] The connecting rod 430 slides through the second hole section 242. One end of the connecting rod 430 is fixedly connected to the mounting column 410, and the other end is fixedly connected to the limiting block 450. The limiting block 450 limits and blocks the feed chute 220.
[0026] The linkage block 440 is located within the elongated groove 250 and is detachably and fixedly connected to the mounting column 410. The linkage block 440 abuts against the side wall of the ejector pin 300. The ejector pin 300 can drive the linkage block 440 to move away from the tufting nozzle 230. When the ejector pin 300 moves towards the tufting nozzle 230, the mounting column 410 moves towards the tufting nozzle 230 under the action of the compression spring 420, thereby causing the limiting block 450 to close the feed groove 220.
[0027] The long groove 250 includes a first groove 251 and a second groove 252, which are interconnected. The first groove 251 is shorter than the second groove 252. The first groove 251 is located on the side closer to the first hole segment 241, and the second groove 252 is located on the side closer to the tufting hole 210. One end of the second groove 252 extends through the end of the tufting block 200 away from the tufting nozzle 230. The linkage block 440 is partially located within the first groove 251 and partially within the second groove 252.
[0028] A contact block 310 is fixed to the side wall of the ejector pin 300. The contact block 310 is fitted into the second groove 252 and is located on the side of the linkage block 440 near the bristle nozzle 230. When the ejector pin 300 moves away from the bristle nozzle 230, the contact block 310 abuts against the linkage block 440 and drives the linkage block 440 to move away from the bristle nozzle 230. When the ejector pin 300 moves to the maximum distance, the linkage block 440 abuts against the end of the first groove 251 away from the bristle nozzle 230.
[0029] The tufted block 200 has an installation hole 270 on the side near the feed trough 220, and the installation hole 270 is connected to the first hole section 241; the installation hole 270 is located within the range of the first trough 251.
[0030] The mounting post 410 has a through first fixing hole 411, and the linkage block 440 has a second fixing hole 441. When the linkage block 440 is located at one end of the first groove 251, the first fixing hole 411, the second fixing hole 441, and the mounting hole 270 are concentric. A fixing screw 460 is threaded into the first fixing hole 411 and the second fixing hole 441. During installation, the linkage block 440 is moved by the ejector pin 300 or by an external tool, so that the linkage block 440 is located at the end of the first groove 251, and the fixing screw 460 passes through the mounting hole 270, with one end located in the first fixing hole 411 and the other end threadedly connected to the second fixing hole 441. The first fixing hole 411 is a stepped hole, and the second fixing hole 441 is a threaded hole.
[0031] The second hole segment 242 has an opening 243 at one end near the tufting nozzle 230 and on the side opposite to the tufting hole 210. An arc-shaped side 244 is formed on the side near the tufting hole 210. The distance between the arc-shaped side 244 and the tufting hole 210 gradually decreases at the end near the tufting nozzle 230. The limiting block 450 always remains within the range of the opening 243 when sliding.
[0032] In one embodiment, the limiting block 450 is rectangular, and a connector 470 is formed at the end of the limiting block 450 away from the tufting nozzle 230. The connector 470 and the connector 430 are fixedly connected by the connector 470 and the connector 430. The connector 470 and the connector 430 are fixedly connected by threads.
[0033] The connecting body 470 has an arc-shaped surface 471 formed on the side near the arc-shaped side 244, which is flush with the side of the limiting block 450. When the limiting block 450 closes the feed groove 220, the arc-shaped surface 471 and the arc-shaped side 244 are in contact. The connecting rod 430 is made of an elastic material. Furthermore, when the limiting block 450 is moved away from the tufting nozzle 230, due to the relationship between the arc-shaped surface 471 and the arc-shaped side 244, the limiting block 450 slides on the arc-shaped side 244. During the sliding process, the limiting block 450 gradually moves away from the tufting hole 210, while when it is close to the tufting nozzle 230, the limiting block 450 gradually moves closer to the tufting hole 210.
[0034] The limiting block 450 has an arc-shaped groove at one end near the tufting hole 210. When the limiting block 450 closes the feed channel 220, the arc-shaped groove is close to the inner wall of the tufting hole 210. With this setting, when the limiting block 450 blocks the feed channel 220, it can surround the tufting hole 210, and during the tufting process, the ejector pin 300 and the copper sheet can pass through the position of the feed channel 220 more effectively.
[0035] The tufting block 200 has a feed hole 280 on its side away from the feed groove 220. The feed hole 280 is perpendicular to the length direction of the tufting hole 210 and communicates with the tufting hole 210. The feed hole 280 is located between the elongated groove 250 and the tufting nozzle 230. The feed hole 280 is used to place the copper sheet into the tufting hole. During tufting, after the copper strip enters the tufting hole, the nozzle cuts the copper strip to form a copper sheet, and then moves the copper sheet.
[0036] The bristle implantation nozzle 230 is V-shaped, with an opening 231 at the tip. Guide plates 232 are formed on both sides of the opening 231. During the implantation process, when the bristle implantation nozzle 230 approaches the bristle hole of the toothbrush, the guide plates 232 on both sides are located on both sides of the bristle hole of the toothbrush, allowing the bristle material and copper sheet to enter the bristle hole of the toothbrush more effectively.
[0037] This invention provides a bristle insertion device for compressed production. A limiting component 400, mounted on the bristle-planting block 200, controls the operation of the limiting component 400 via a push pin 300. Each time bristle material is placed into the feed trough 220, directly opposite the bristle-planting hole 210, the limiting component 400 closes and limits the feed trough 220, preventing the bristle material from moving outwards and falling during the bristle-planting process. After one bristle material has been planted, the limiting component 400 retracts from the feed trough 220, opening it for further material feeding. This limiting component 400 effectively limits and blocks material from the feed trough 220 without hindering normal material supply through it.
[0038] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," "front," and "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0039] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Without conflict, the embodiments and features in the embodiments of this invention can be combined with each other.
[0040] The embodiments described above are merely illustrative of implementation methods of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.
Claims
1. A bristle insertion device for toothbrush production, mounted on a bristle implantation machine, comprising a mounting base (100) detachably and fixedly connected to the bristle implantation machine, wherein a through moving channel (110) is formed in the middle of the mounting base (100), a bristle implantation block (200) is slidably connected to the moving channel (110), a bristle implantation hole (210) is formed in the bristle implantation hole (210) along its length, and a pin (300) is slidably connected in the bristle implantation hole (210); a feeding groove (220) is formed on one side wall of the outer side of the bristle implantation block (200), the feeding groove (220) communicating with the bristle implantation hole (210); one end of the bristle implantation hole (210) forms a bristle implantation nozzle (230), characterized in that, A limiting hole (240) is provided on the tufting block (200) and on one side of the tufting hole (210). The limiting hole (240) is parallel to the tufting hole (210) and communicates with the feed chute (220). An elongated groove (250) is provided between the limiting hole (240) and the tufting hole (210). A limiting component (400) is provided in the limiting hole (240). One end of the positioning component (400) can enter the feed groove (220) through the limiting hole (240). When the ejector pin (300) moves towards the end closer to the tufting nozzle (230), the limiting component (400) limits the feed groove (220). When the ejector pin (300) moves away from the end of the tufting nozzle (230), the ejector pin (300) controls the limiting component (400) to disengage from the feed groove (220).
2. The toothbrush bristle insertion device for toothbrush production according to claim 1, characterized in that, The limiting hole (240) includes a first hole section (241) and a second hole section (242); The first hole segment (241) is located at the end away from the tufting nozzle (230), and the second hole segment (242) is located at the end close to the tufting nozzle (230); the diameter of the first hole segment (241) is larger than the diameter of the second hole segment (242); a plug (260) is threadedly connected to the end of the first hole segment (241) away from the second hole segment (242); the long groove (250) is connected to the first hole segment (241).
3. The toothbrush bristle insertion device for toothbrush production according to claim 2, characterized in that, The limiting component (400) includes a mounting post (410), a compression spring (420), a connecting rod (430), a linkage block (440), and a limiting block (450). The mounting post (410) and the compression spring (420) are slidably connected in the first hole section (241). One end of the compression spring (420) abuts against the mounting post (410), and the other end abuts against the plug (260). The connecting rod (430) slides through the second hole section (242), one end of the connecting rod (430) is fixedly connected to the mounting post (410), and the other end is fixedly connected to the limiting block (450). The linkage block (440) is located in the long groove (250) and is detachably and fixedly connected to the mounting column (410). The linkage block (440) abuts against the side wall of the ejector pin (300).
4. The toothbrush bristle insertion device for toothbrush production according to claim 3, characterized in that, The long groove (250) includes a first groove body (251) and a second groove body (252), the first groove body (251) and the second groove body (252) are connected to each other, and the length of the first groove body (251) is smaller than that of the second groove body (252); The first groove (251) is located on the side close to the first hole segment (241), the second groove (252) is located on the side close to the hair implantation hole (210), and one end of the second groove (252) in the length direction passes through the end of the hair implantation block (200) away from the hair implantation nozzle (230). The ejector pin (300) has a stop block (310) fixed on its side wall. The stop block (310) is fitted into the second groove (252) and is located on the side of the linkage block (440) near the tufting nozzle (230). When the ejector pin (300) moves away from the tufting nozzle (230), the stop block (310) abuts against the linkage block (440) and drives the linkage block (440) to move away from the tufting nozzle (230). When the ejector pin (300) moves to the maximum distance, the linkage block (440) abuts against the end of the first groove (251) away from the tufting nozzle (230).
5. A bristle inserting device for toothbrush production according to claim 4, characterized in that, The flocking block (200) has a mounting hole (270) on the side near the feed trough (220), and the mounting hole (270) is connected to the first hole section (241); the mounting hole (270) is located within the area of the first trough (251); The mounting post (410) has a through first fixing hole (411), and the linkage block (440) has a second fixing hole (441). When the linkage block (440) is located at one end of the first groove (251), the first fixing hole (411) and the second fixing hole (441) are concentric with the mounting hole (270). A fixing screw (460) is connected in the first fixing hole (411) and the second fixing hole (441).
6. The toothbrush bristle insertion device for toothbrush production according to claim 3, characterized in that, The second hole segment (242) has an opening (243) at one end near the tufting nozzle (230) and on the side opposite to the tufting hole (210), and an arc-shaped side (244) is formed on the side near the tufting hole (210); the arc-shaped side (244) at the end near the tufting nozzle (230) gradually decreases in distance from the tufting hole (210); the limiting block (450) always remains within the range of the opening (243) when it slides; The limiting block (450) is rectangular, and a connector (470) is formed at the end of the limiting block (450) away from the tufting nozzle (230). An arc surface (471) is formed on the side of the connector (470) near the arc side (244). When the limiting block (450) closes the feed chute (220), the arc surface (471) and the arc side (244) fit together. The connecting rod (430) is made of elastic material.
7. The toothbrush bristle insertion device for toothbrush production according to claim 3, characterized in that, The limiting block (450) has an arc-shaped groove at one end near the hair implantation hole (210). When the limiting block (450) closes the feed chute (220), the arc-shaped groove is close to the inner wall of the hair implantation hole (210).
8. The toothbrush bristle insertion device according to claim 1, characterized in that, The tufting block (200) has a feed hole (280) on one side away from the feed trough (220). The feed hole (280) is perpendicular to the length direction of the tufting hole (210) and communicates with the tufting hole (210). The feed hole (280) is located between the long groove (250) and the tufting nozzle (230).
9. A bristle inserting device for toothbrush production according to claim 1, characterized in that, The tufting nozzle (230) is V-shaped, with an opening (231) at the tip, and guide plates (232) are formed on both sides of the opening (231).