A rotary blow mold opening and closing device

Abstract

The present invention relates to a rotary blow mold opening and closing device, comprising a mold frame, a blow mold arranged on the mold frame and a mold opening and closing mechanism, wherein the blow mold comprises a left mold and a right mold that can be rotatably matched and a bottom mold matched with the bottoms of the left mold and the right mold, and the mold opening and closing mechanism is arranged on the rear side of the blow mold, and drives the left mold and the right mold to rotate and drives the bottom mold to move up and down by moving along the radial direction of the rotation trajectory of the blow mold, thereby realizing the opening and closing of the blow mold; a limiting mechanism is arranged on the moving path of the mold opening and closing mechanism, and the limiting mechanism locks the blow mold after the mold is closed by means of a card slot engagement; the present invention solves the problems of complex structure, high manufacturing cost, high operating noise and poor stability of the existing mold opening and closing mechanism.

Description

Technical Field

[0001] The invention relates to the technical field of bottle preform blow molding equipment, in particular to a rotary blow molding mold opening and closing device. Background Art

[0002] The blow molding of bottle blanks can be roughly divided into linear blow molding and rotary blow molding. Both blow molding methods have their own advantages and disadvantages. Rotary blow molding has higher efficiency, but a structure needs to be set up during the rotation process to realize the automatic opening and closing of the mold. In this process, on the one hand, the accuracy of opening and closing must be guaranteed, and on the other hand, the closing stability of the mold is also required to be high.

[0003] A Chinese invention patent with authorization publication number CN106170383B discloses a blow mold for blow molding thermoplastic material containers, including two half molds and a drum cam, a first cam follower and a rod for transmitting the opening and closing movement of the two half molds imparted by the movement of the first cam follower, the two half molds have a cyclic opening and closing device, which causes the two half molds to move toward and away from each other by an opening angle, the range of the opening angle varies from 0° in the closed position of the two half molds to an αmax value in the maximum open position of the two half molds, the drum cam includes a second cam track, which can be followed by the first cam follower instead of the first cam track to produce a second cyclic opening and closing movement of the two half molds so as to allow a container with a diameter larger than the first diameter to be extracted from the blow mold.

[0004] However, during actual use, the inventor discovered the following technical problems: its opening and closing mold structure is relatively complex, the production cost is high and it is inconvenient to maintain; in addition, the opening and closing mold of the equipment does not have the function of automatic locking, and it is easy to expand when the blow molding pressure is high. Summary of the invention

[0005] The purpose of the present invention is to address the deficiencies in the prior art and to provide a rotary blow mold opening and closing device, which achieves the opening and closing of the blow mold by arranging the opening and closing mechanism of the blow mold on its rear side and driving the opening and closing mechanism to move along the radial direction of the rotation track during rotation with the help of a track groove, and arranging a limiting mechanism to limit and lock the opening and closing mechanism in the closed state of the mold, thereby solving the problems of the existing opening and closing mechanism having a complex structure, high manufacturing cost, high operating noise and poor stability.

[0006] In view of the above technical problems, the technical solutions adopted are as follows:

[0007] A rotary blow mold opening and closing device comprises a mold frame, a blow mold arranged on the mold frame, and a mold opening and closing mechanism, wherein the blow mold comprises a left mold and a right mold that can be rotatably matched and a bottom mold that matches the bottoms of the left mold and the right mold, and the mold opening and closing mechanism is arranged at the rear side of the blow mold, and drives the left mold and the right mold to rotate and drives the bottom mold to move up and down by moving along the radial direction of the rotation track of the blow mold, thereby realizing the opening and closing of the blow mold;

[0008] A limiting mechanism is arranged on the moving path of the mold opening and closing mechanism, and the limiting mechanism locks the blow mold after the mold is closed by means of a clamping groove.

[0009] As a preference, the mold opening and closing mechanism rotates together with the blow mold, and moves along the radial direction of the rotation track by means of track limiting guidance during the rotation process.

[0010] As a preferred embodiment, the left mold and the right mold of the blow mold each include a mold body portion, a hinge portion arranged at the tail of the mold body portion, and a lever portion extending outward from the hinge portion;

[0011] The left mold and the right mold are both rotatably arranged on a rotating shaft on the mold frame through a hinged part.

[0012] As a preferred embodiment, a sliding seat a is provided on the mold frame, and the mold opening and closing mechanism includes a sliding rod a slidably arranged on the sliding seat a, a bracket fixedly connected to the sliding rod a, a rod a and a rod b symmetrically arranged and rotatably arranged on the bracket, a transmission block a fixedly connected to the rod a at one end, and a transmission block b fixedly connected to the rod b at one end;

[0013] The lever parts of the left mold and the right mold are both fixedly connected with a rod c, and the transmission block a and the transmission block b are rotatably connected with the rod c on the left mold and the right mold respectively;

[0014] The bracket can also be rotatably provided with a guide wheel a, and a track plate is correspondingly arranged below it. The track plate is provided with a track groove a for limiting and guiding the guide wheel a, and the track groove a includes a closed section a and an open mold section a.

[0015] As a preferred embodiment, the mold opening and closing mechanism also includes a sliding seat b arranged on the mold frame, a sliding rod b sliding up and down along the sliding seat b, and a connecting rod fixedly connected to the bracket, the sliding rod b is fixedly connected to the bottom mold, and a guide wheel b is rotatably provided at the end of the connecting rod, and a guide block is correspondingly provided on the side of the sliding rod b, and a track groove b is provided on the guide block for limiting and guiding the guide wheel b, and the track groove b includes a closing section b and a mold opening section b.

[0016] Preferably, the limiting mechanism comprises a lifting assembly and a locking assembly, wherein the lifting assembly realizes lifting movement by means of a limiting guide during the rotation of the blow mold, and drives the locking assembly to move sideways during the lifting process to realize the locking or release of the slide rod a.

[0017] As a preferred embodiment, the lifting assembly includes a sliding seat c fixed on the mold frame and a lifting rod passing through the bottom plate of the mold frame and slidingly cooperating with the sliding seat c, the lower end of the lifting rod is provided with a support block a, the support block a is provided with a guide wheel c, and an arc-shaped boss is provided below it correspondingly, the guide wheel c drives the lifting rod to rise under the guidance of the arc-shaped boss and resets downward under the action of elastic force, and the arc-shaped boss is provided at the position corresponding to the mold opening section a;

[0018] The engaging assembly includes a support block b fixed to the upper end of the lifting rod, a guide wheel d rotatably arranged on the support block b, a sliding seat d fixed to the mold frame and located on one side of the sliding rod a, and a limiting slider slidable left and right in the sliding seat d, the limiting slider is provided with an oblique groove, the guide wheel d cooperates with the oblique groove, and the sliding rod a is provided with a slot cooperating with the limiting slider.

[0019] As a preferred embodiment, a spring sleeved on the lifting rod is provided between the bottom plate and the sliding seat c.

[0020] As a preference, the end of the transmission block a is provided with an arcuate tooth portion a coaxial with the rod a, and the end of the transmission block b is provided with an arcuate tooth portion b coaxial with the rod b, and the arcuate tooth portion a is meshed with the arcuate tooth portion b.

[0021] As another preferred embodiment, the slide rod a and the bracket are fixedly connected via a connecting rod, and a slide groove is provided on the mold frame for the bracket to move forward and backward.

[0022] Beneficial effects of the present invention:

[0023] 1. In the present invention, the opening and closing mold mechanism of the blow mold is arranged at the rear side thereof, and the track groove is used to drive the opening and closing mold mechanism to move along the radial direction of the rotation track during the rotation process to drive the left mold and the right mold to rotate and drive the bottom mold to move up and down, thereby realizing the opening and closing of the blow mold. Compared with the existing opening and closing mechanism arranged at the opening of the blow mold, the present invention has a simple structure, low manufacturing cost, reduced operating noise and better stability.

[0024] 2. The present invention overcomes the defects of the mold opening and closing mechanism that the closure is not firm and it is easy to expand when the blow molding pressure is high by arranging a limit mechanism on the mold opening and closing movement path of the mold opening and closing mechanism. The cam structure is used to realize the lifting movement during the rotation process and then drives the limit slider to be stuck in the slot through the oblique groove. The limit structure is simple, does not require additional power, has stable limit and high accuracy.

[0025] 3. In the present invention, a track groove b is provided and a guide wheel b is provided on the connecting rod to cooperate with the track groove b, so that when the mold is opened and closed, the movement along the radius of the rotating track can be utilized to drive the guide block provided with the track groove b to move up and down, and then drive the bottom mold to move up and down to open and close the mold. Compared with the existing connecting rod transmission method, this structure is more stable in operation and simpler in manufacturing and assembly. The sealing of the mold can be ensured only by precise processing of the track groove b.

[0026] In summary, the device has the advantages of simple structure, low manufacturing cost, good operation stability, etc., and is particularly suitable for the technical field of bottle preform blow molding equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0028] Figure 1 It is a schematic diagram of the front axis side of the rotary blow mold opening and closing device;

[0029] Figure 2 It is a schematic diagram of the rear axle side of the rotary blow mold opening and closing device;

[0030] Figure 3 It is a structural schematic diagram of the mold opening and closing mechanism and the limiting mechanism;

[0031] Figure 4 It is a schematic diagram of the opening and closing structure of the bottom mold part of the mold opening and closing mechanism;

[0032] Figure 5 It is a structural schematic diagram of the limiting mechanism;

[0033] Figure 6 is a structural schematic diagram of a clamping assembly;

[0034] Figure 7 It is a structural schematic diagram of a blow mold;

[0035] Figure 8 It is the structural diagram of the left mold;

[0036] Fig. 9 It is a top view schematic diagram of the rotary blow mold opening and closing device. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present invention are clearly and completely described below in conjunction with the accompanying drawings.

[0038] Embodiment 1

[0039] like Figures 1 to 9 As shown, a rotary blow mold opening and closing device comprises a mold frame 1, a blow mold 2 arranged on the mold frame 1, and a mold opening and closing mechanism 3, wherein the blow mold 2 comprises a left mold 21 and a right mold 22 that can be rotatably matched, and a bottom mold 23 that matches the bottoms of the left mold 21 and the right mold 22, and the mold opening and closing mechanism 3 is arranged at the rear side of the blow mold 2, and drives the left mold 21 and the right mold 22 to rotate and drives the bottom mold 23 to move up and down by moving along the radial direction of the rotation track of the blow mold 2, thereby realizing the opening and closing of the blow mold 2;

[0040] A limiting mechanism 4 is arranged on the moving path of the mold opening and closing mechanism 3 , and the limiting mechanism 4 locks the blow mold 2 after mold closing by means of a clamping groove.

[0041] Furthermore, the mold opening and closing mechanism 3 rotates together with the blow mold 2, and moves along the radial direction of the rotation track by means of track limiting guidance during the rotation process.

[0042] Furthermore, the left mold 21 and the right mold 22 of the blow mold 2 each include a mold body portion 211, a hinge portion 212 disposed at the rear of the mold body portion 211, and a lever portion 213 extending outward from the hinge portion 212;

[0043] The left mold 21 and the right mold 22 are both rotatably arranged on the rotating shaft 11 on the mold frame 1 through the hinge part 212.

[0044] Furthermore, a sliding seat a12 is provided on the mold frame 1, and the mold opening and closing mechanism 3 includes a sliding rod a31 slidably provided on the sliding seat a12, a bracket 32 ​​fixedly connected to the sliding rod a31, a rod a33 and a rod b34 symmetrically provided and rotatably provided on the bracket 32, a transmission block a35 fixedly connected to the rod a33 at one end, and a transmission block b36 fixedly connected to the rod b34 at one end;

[0045] The lever parts 213 of the left mold 21 and the right mold 22 are both fixedly connected with a rod c37, and the transmission block a35 and the transmission block b36 are rotatably connected with the rod c37 on the left mold 21 and the right mold 22 respectively;

[0046] The bracket 32 ​​is also rotatably provided with a guide wheel a38, and a track plate 39 is correspondingly provided below it. The track plate 39 is provided with a track groove a391 for limiting and guiding the guide wheel a38, and the track groove a391 includes a closing section a10 and an opening section a20.

[0047] It is worth mentioning that by setting the opening and closing mold mechanism 3 of the blow mold 2 on its rear side, and using the track groove to drive the opening and closing mold mechanism 3 to move along the radial direction of the rotation track during rotation, the left mold 21 and the right mold 22 are driven to rotate and the bottom mold 23 is driven to move up and down, thereby realizing the opening and closing of the blow mold 2. Compared with the existing opening and closing mechanism set at the opening of the blow mold 2, its structure is simple, the production cost is low, the operating noise is reduced and the stability is better.

[0048] Furthermore, the mold opening and closing mechanism 3 also includes a sliding seat b100 arranged on the mold frame 1, a sliding rod b101 sliding up and down along the sliding seat b100, and a connecting rod 102 fixedly connected to the bracket 32, the sliding rod b101 is fixedly connected to the bottom mold 23, and the end of the connecting rod 102 is rotatably provided with a guide wheel b103, and a guide block 104 is correspondingly provided on the side of the sliding rod b101, and a track groove b105 for limiting and guiding the guide wheel b103 is opened on the guide block 104, and the track groove b105 includes a closing section b30 and a mold opening section b50.

[0049] In addition, by setting the track groove b105 and setting the guide wheel b103 on the connecting rod 102 to cooperate with the track groove b105, when opening and closing the mold, the movement along the radial direction of the rotating track can be utilized to drive the guide block 104 with the track groove b105 to move up and down, and then drive the bottom mold 23 to move up and down to open and close the mold. Compared with the existing connecting rod transmission method, this structure is more stable in operation and simpler in manufacturing and assembly. The sealing of the mold can be guaranteed by only precise processing of the track groove b105.

[0050] Furthermore, the end of the transmission block a35 is provided with an arc-shaped tooth portion a351 coaxial with the rod a33, and the end of the transmission block b36 is provided with an arc-shaped tooth portion b361 coaxial with the rod b34, and the arc-shaped tooth portion a351 and the arc-shaped tooth portion b361 are meshed.

[0051] Furthermore, the slide rod a31 and the bracket 32 ​​are fixedly connected via a connecting rod 46, and a slide groove 14 is provided on the mold frame 1 for the bracket 32 ​​to move forward and backward.

[0052] Embodiment 2

[0053] like Figure 5 and Figure 6As shown, the components identical or corresponding to those in the first embodiment are marked with the corresponding reference numerals in the first embodiment. For the sake of simplicity, only the differences from the first embodiment are described below. The second embodiment is different from the first embodiment in that: further, the limiting mechanism 4 includes a lifting assembly 41 and a clamping assembly 42. The lifting assembly 41 realizes lifting and lowering movement by means of limiting guide during the rotation of the blow mold 2, and drives the clamping assembly 42 to move sideways during the lifting and lowering process to realize the clamping or releasing of the slide bar a31.

[0054] Further, the lifting assembly 41 includes a sliding seat c411 fixed on the mold frame 1 and a lifting rod 412 passing through the bottom plate 13 of the mold frame 1 and slidingly cooperating with the sliding seat c411, the lower end of the lifting rod 412 is provided with a support block a414, the support block a414 is provided with a guide wheel c415, and an arc-shaped boss 416 is correspondingly provided below it, the guide wheel c415 drives the lifting rod 412 to rise under the guidance of the arc-shaped boss 416 and resets downward under the action of elastic force, and the arc-shaped boss 416 is provided at the position corresponding to the mold opening section a20;

[0055] The engaging assembly 42 includes a support block b421 fixed to the upper end of the lifting rod 412, a guide wheel d422 rotatably arranged on the support block b421, a sliding seat d423 fixed on the mold frame 1 and located on one side of the slide rod a31, and a limiting slider 424 slidable left and right in the sliding seat d423, the limiting slider 424 is provided with an oblique groove 425, the guide wheel d422 cooperates with the oblique groove 425, and the slide rod a31 is provided with a slot 311 cooperating with the limiting slider 424.

[0056] It should be pointed out that by arranging a limit mechanism 4 on the opening and closing moving path of the mold opening and closing mechanism 3, the defects of this type of mold opening and closing mechanism, such as loose closure and easy expansion when the blow molding pressure is high, are overcome. The cam structure is used to realize the lifting movement during the rotation process, and then the limit slider 424 is driven to be inserted into the card slot 311 through the inclined groove 425. This type of limit structure is simple, does not require additional power, has stable limit and high accuracy.

[0057] Furthermore, a spring 413 sleeved on the lifting rod 412 is provided between the bottom plate 13 and the sliding seat c411.

[0058] Working process:

[0059] It should be noted that in specific use, the main shaft is also provided at the center of the track plate 39, and the mold frame 1 and the blow mold 2 are provided with a plurality of shafts along the circumferential direction of the main shaft, which drive the mold frame 1 and the blow mold 2 to rotate; during the rotation process, when the guide wheel a38 is located at the closed section a10, the left mold 21, the right mold 22 and the bottom mold 23 are in a closed state, and before the guide wheel a38 is about to turn into the open mold section a20, the arc-shaped boss 416 acts on the guide wheel c415, so that the lifting rod 412 rises and the limit slider 424 slides outward from the slot 311 on the slide rod a31 through the cooperation of the guide wheel d422 and the oblique groove 425;

[0060] The mold continues to rotate. Under the cooperation of the guide wheel a38 and the mold opening section a20, the slide bar a31 moves toward the rotation axis so that the left mold 21 and the right mold 22 are opened. At the same time, the guide wheel b103 is driven by the connecting rod 102 to move along the track groove b105 so that the guide block 104 and the bottom mold 23 slide downward to complete the opening of the mold.

[0061] When entering the closed section a10 again, the slide bar a31 is reset, and the lifting rod 412 is also reset under the action of gravity and the spring, so that the limit slider 424 is locked in the slot 311 after the mold is closed.

[0062] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by the terms "front and back", "left and right", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the invention.

[0063] Of course, in the present technical solution, those skilled in the art should understand that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0064] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art under the technical guidance of the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A rotary blow mold opening and closing device, comprising a mold frame (1), a blow mold (2) arranged on the mold frame (1), and a mold opening and closing mechanism (3), wherein the blow mold (2) comprises a left mold (21) and a right mold (22) that can be rotatably matched, and a bottom mold (23) that matches the bottom of the left mold (21) and the right mold (22), characterized in that: The mold opening and closing mechanism (3) is arranged at the rear side of the blow mold (2), and drives the left mold (21) and the right mold (22) to rotate and drives the bottom mold (23) to move up and down by moving along the radial direction of the rotation track of the blow mold (2), thereby realizing the opening and closing of the blow mold (2); A limit mechanism (4) is provided on the moving path of the mold opening and closing mechanism (3), and the limit mechanism (4) locks the blow mold (2) after the mold is closed by means of a clamping groove; The mold frame (1) is provided with a sliding seat a (12), and the mold opening and closing mechanism (3) comprises a sliding rod a (31) slidably arranged on the sliding seat a (12), a bracket (32) fixedly connected to the sliding rod a (31), a rod a (33) and a rod b (34) symmetrically arranged and rotatably arranged on the bracket (32), a transmission block a (35) one end of which is fixedly connected to the rod a (33), and a transmission block b (36) one end of which is fixedly connected to the rod b (34); The lever parts (213) of the left mold (21) and the right mold (22) are both fixedly connected with a rod c (37), and the transmission block a (35) and the transmission block b (36) are rotatably connected to the rod c (37) on the left mold (21) and the right mold (22) respectively; The support (32) is also rotatably provided with a guide wheel a (38), and a track plate (39) is correspondingly provided below the support (32), and a track groove a (391) for limiting and guiding the guide wheel a (38) is provided on the track plate (39), and the track groove a (391) includes a closing section a (10) and a mold opening section a (20); The mold opening and closing mechanism (3) also includes a sliding seat b (100) arranged on the mold frame (1), a sliding rod b (101) sliding up and down along the sliding seat b (100), and a connecting rod (102) fixedly connected to the bracket (32), the sliding rod b (101) is fixedly connected to the bottom mold (23), the end of the connecting rod (102) is rotatably provided with a guide wheel b (103), and a guide block (104) is correspondingly provided on the side of the sliding rod b (101), and a track groove b (105) is provided on the guide block (104) for limiting and guiding the guide wheel b (103), and the track groove b (105) includes a closing section b (30) and a mold opening section b (50); The end of the transmission block a (35) is provided with an arc-shaped tooth portion a (351) coaxial with the rod a (33), and the end of the transmission block b (36) is provided with an arc-shaped tooth portion b (361) coaxial with the rod b (34), and the arc-shaped tooth portion a (351) and the arc-shaped tooth portion b (361) are meshed; The limiting mechanism (4) comprises a lifting component (41) and a locking component (42); the lifting component (41) realizes lifting movement by means of a limiting guide in the process of rotating with the blow mold (2), and drives the locking component (42) to move sideways in the process of lifting to realize locking or releasing of the slide bar a (31); The lifting assembly (41) comprises a sliding seat c (411) fixed on the mold frame (1) and a lifting rod (412) passing through the bottom plate (13) of the mold frame (1) and slidingly cooperating with the sliding seat c (411); a support block a (414) is provided at the lower end of the lifting rod (412); a guide wheel c (415) is provided on the support block a (414); and an arc-shaped boss (416) is provided below the support block a (414); the guide wheel c (415) drives the lifting rod (412) to rise under the guidance of the arc-shaped boss (416) and resets downward under the action of elastic force; and the arc-shaped boss (416) is provided at the position corresponding to the mold opening section a (20); The engaging assembly (42) comprises a support block b (421) fixed to the upper end of the lifting rod (412), a guide wheel d (422) rotatably arranged on the support block b (421), a sliding seat d (423) fixed to the mold frame (1) and located on one side of the sliding rod a (31), and a limit slider (424) slidable left and right in the sliding seat d (423), the limit slider (424) is provided with an oblique groove (425), the guide wheel d (422) cooperates with the oblique groove (425), and the sliding rod a (31) is provided with a slot (311) cooperating with the limit slider (424); When the guide wheel a (38) is about to turn into the mold opening section a (20), the arc-shaped boss (416) acts on the guide wheel c (415), causing the lifting rod (412) to rise and, through the cooperation between the guide wheel d (422) and the oblique groove (425), the limit slider (424) slides outward to disengage from the slot (311) on the slide rod a (31); the rotation continues, and under the cooperation between the guide wheel a (38) and the mold opening section a (20), the slide rod a (31) moves toward the rotation axis, causing the left mold (21) and the right mold (22) to open. At the same time, the guide wheel b (103) is driven by the connecting rod (102) to move along the track groove b (105), causing the guide block (104) and the bottom mold (23) to slide downward to complete the opening of the mold.

2. A rotary blow mold opening and closing device according to claim 1, characterized in that: The mold opening and closing mechanism (3) rotates together with the blow mold (2), and moves along the radial direction of the rotation track by means of track limit guidance during the rotation process.

3. A rotary blow mold opening and closing device according to claim 2, characterized in that: The left mold (21) and the right mold (22) of the blow mold (2) each comprise a mold body portion (211), a hinge portion (212) arranged at the rear of the mold body portion (211), and a lever portion (213) extending outward from the hinge portion (212); The left mold (21) and the right mold (22) are both rotatably arranged on a rotating shaft (11) on the mold frame (1) via a hinged portion (212).

4. A rotary blow mold opening and closing device according to claim 1, characterized in that: A spring (413) sleeved on the lifting rod (412) is arranged between the bottom plate (13) and the sliding seat c (411).

5. A rotary blow mold opening and closing device according to claim 1, characterized in that: The slide rod a (31) and the bracket (32) are fixedly connected via a connecting rod (46), and a slide groove (14) is provided on the mold frame (1) for the bracket (32) to move forward and backward.

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