TECHNICAL FIELD

[0001] The disclosure relates to a field of punching die, particularly a punching die for pulp molding product with a plurality of cavities.

BACKGROUND

[0002] It is increasingly popular to use, for example pulp molding products, for packing a product nowadays. For instance, a tray made of paper for carrying a product in a packaging box of electronic products such as mobile phone, tablet and the like is a common example. By way of the manufacture of such a tray, it is always obtained by using a punching die to cut and separate a blank comprising a plurality of trays, said blank is molded by pressing.

[0003] Currently, the cutting die with multiple cavities for cutting pulp molding product usually has a fixed center distance which cannot be moved, which thus easily causes an issue of unevenness at the cutted edges of the product with multiple cavities when cutting the same, typically wide and narrow edges being formed in a product at the same time, this is because of the instability of shrinking after hot pressing, and it is difficult to adjust the cutting die. In addition, in the step of cutting, a way of backside positioning is often used to position a pulp molding product, however the backside of the pulp molding product is wire side, which would cause a poor precision of positioning and in turn a big dimensional deviation at the cutted edges.

SUMMARY

[0004] The disclosure aims to propose a punching die which can overcome the defects mentioned above. The punching die according to the disclosure is characterized in that it comprises:

[0005] an upper die assembly comprising:

[0006] an upper die plate,

[0007] a cutting seat fixed to the upper die plate, [0008] a lower die assembly comprising:

[0009] a lower die plate,

[0010] a supporting plate fixed on the lower die plate,

[0011] wherein the lower die assembly further comprises a plurality of separate cutting modules, each of the cutting modules corresponding to one unit of a piece to be cut located between the upper die assembly and the lower die assembly, the cutting modules each comprise:

[0012] a fixing plate for cutting plate which is slidably supported on the supporting plate,

[0013] a cutting plate which is fixed on the fixing plate for cutting plate and on which positioned a blade.

[0014] Compared to the cutting plate with a whole piece in the prior art, the horizontal positions (positions in the XY plane) of the plurality of separate cutting units which can slide relative to the supporting plate can be adjusted when the upper die engages with the lower die, i.e., at that time the cutting modules can slide in translation. Therefore, the problem of the uneven edges (wide and narrow edges) of the product units can be settled very well.

[0015] Preferably, the cutting modules is supported on the supporting plate in a manner of being translated with respect to the supporting plate.

[0016] Preferably, the fixing plate for cutting plate is slidably supported on the supporting plate by a rolling assembly. The arrangement of the rolling assembly may effectively reduce the friction force between the fixing plate for cutting plate and the support, causing the relative sliding between them easier, that is to say, only small transverse force (force in the XY plane) can cause the cutting modules to slide in translation. Additionally, by providing rolling assemblies between the upper surface of the supporting plate and the lower surface of the fixing plate for cutting plate, a gap is created between the two surfaces, and thus the two surfaces do not contact with each other in a large area, which further facilitates the relative sliding between the support and the fixing plate for cutting plate.

[0017] Preferably, the rolling assembly comprises a bailhead plunger which has a body mounted in the supporting plate and a head slightly higher than an upper surface of the supporting plate to support the fixing plate for cutting plate.

[0018] Preferably, the rolling assembly comprises a recess provided on an upper surface of the supporting plate and a rolling ball located in the recess.

[0019] Preferably, the cutting modules a sliding limit pin, which passes through, in this order, a first cutting plate through-hole in the cutting plate and a first fixing plate through-hole in the fixing plate for cutting plate, and fixed to the supporting plate, and wherein the first cutting plate through-hole and the first fixing plate through-hole have a greater diameter than the sliding limit pin.

[0020] Preferably, the cutting modules comprise a plurality of sliding limit pins.

[0021] Preferably, the cutting seat has housing spaces for accommodating each unit of the piece to be cut, and comprises a receiving table fixed to the upper die plate and a lining plate, the receiving table being positioned between the upper die plate and the lining plate.

[0022] Preferably, the lower die assembly additionally comprises separate cores corresponding to the separate cutting modules, the separate cores being mounted on the corresponding cutting plate in a floatable manner.

[0023] Preferably, the lower die assembly comprises a floatable mounting assembly for the core which comprises a fixing pin and a spring, the fixing pin comprising a first section in the core, a second section located in the cutting plate and passing through the cutting plate, and a third section fixed in the fixing plate for cutting plate, wherein the spring is provided around the second section.

[0024] In use, each of the cavities of the piece to be cut covers a core. Since the piece to be cut has a stereo shape, it would apply a certain transverse force to each of the cores when covering it. As the fixing plate for cutting plate fixed relative to the core can slide in translation with respect to the supporting plate, the transverse force can actuate the corresponding cutting module to translate accordingly, so that, as to this unit of this piece to be cut, the horizontal position of the corresponding cutting module is adjusted, and thus the center distances between the cutting modules can be adjusted. That is to say, each unit of the piece to be cut is cut based on its precise center, the problem of uneven edges being settled.

[0025] Further, the piece to be cut contacts the cores with its upper surface, i.e. position with from face. As the cores are floatable, when the upper die assembly presses downwardly, the piece to be cut along with the floatable cores move downwardly, the blades cuts into the piece to be cut from the bottom up, achieving a accurate positioning and a high precision of cutting.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Those skilled in the art will have a better understanding of the present disclosure and the advantages of the present disclosure will be more clearly reflected, from the drawings below. The drawings described here are only for the purpose of illustrating the embodiments instead of all the feasible implementations, and are not intended to limit the scope of the present disclosure.

[0027] Fig. 1 shows a schematic perspective view of a punching die according to the disclosure;

[0028] Fig. 2 shows a schematic perspective view of a punching die with three cavities, wherein a cutting plate of the cutting module in the middle is not shown in order to show the details of the structure more clearly, and the cutting module rightmost is not shown in order to show an embodiment of rolling assembly more clearly;

[0029] Fig. 3 shows a schematic partial perspective view of a lower die assembly of punching die according to the disclosure;

[0030] Fig. 4 shows a schematic sectional view of a punching die according to the disclosure, taken along a section with a rolling assembly;

[0031] Fig. 5 shows a schematic sectional view of another embodiment of a rolling assembly according to the disclosure;

[0032] Fig. 6 shows a schematic sectional view of a cutting assembly according to the disclosure;

[0033] Fig. 7 shows a schematic sectional view of a mounting form of floatable core according to the disclosure; and

[0034] Fig. 8 shows a schematic sectional view of one of cutting assemblies.

DETAILED DESCRIPTION

[0035] A clear and complete description will be made to technical solution of the embodiments of the disclosure in combination with the drawings of the embodiments, for making the objective, the solutions and the advantages more apparent.

[0036] Unless otherwise defined, the technical terms or scientific terms used herein shall have common meanings understood by those skilled in the art. The words such as “comprise” or “contain” or the like is intended to indicate that the element or object before this word covers the element(s) or object(s) listed after this word, without excluding other element or object.

[0037] For better describing the technical solution according to the disclosure, an orthogonal coordinate system XYZ is established, wherein axes X and Y form a XY plane on which the punching die is placed in an normal operation status, and an axis Z is perpendicular to the XY plane and has a positive direction pointing to the upper die assembly. The terms “upper” and “lower” directions are defined with respect to the axis Z.

[0038] Now please refer to Fig. 1. Fig. 1 schematically shows a perspective exploded view of a punching die 1 according to the disclosure.

[0039] As shown in Fig. 1, the punching die 1 may comprise an upper die assembly 10 and a lower die assembly 20. The punching die is used for punching pulp molding product. In a normal operation status, the lower die assembly 20 is placed in a plane defined by the axis X and the axis Y, which is for example a machine table plane.

[0040] The upper die assembly 10 comprises an upper die plate 110 which can be a rectangular plate with a certain thickness, for example an aluminum plate. The upper die assembly 10 further comprises a cutting seat 120 which is fixed to the upper die plate 110. The cutting seat 120 is a portion for receiving blade during the lunching operation of the punching die.

[0041] The lower die assembly 20 may comprises a lower die plate 210 which may also be a rectangular plate with a certain thickness, for example an aluminum plate. The lower die assembly 20 further comprises a supporting plate 220 fixed on the lower die plate 210. The supporting plate 220 may be used to support cutting modules, which will be described below.

[0042] When the punching die is working, a piece to be cut 90 is arranged between the upper die assembly 10 and the lower die assembly 20, the upper die plate 110 along with the cutting seat 120 fixed thereon move downward and engage with the lower die assembly 20 to cut the piece to be cut 90 into units as required. In the example shown in Fig. 1, the piece to be cut 90 is a piece to be cut with multiple cavities, specifically, having three cavities, and after punched, this piece to be cut is separated into three individual units. The piece to be cut 90 is a pulp molding product, which is produced by for example molding in wet press die and then by hot-pressing.

[0043] As shown in Fig. 1, the cutting seat 120 may have housing spaces 125 for receiving each of the units of the piece to be cut 90. The cutting seat 120 may comprise a receiving table 121 and a lining plate 122 fixed to the upper die plate 110, with the receiving table 121 positioned between the upper die plate 110 and the lining plate 122. The receiving table 121 may be a plate with a certain thickness and made of polyvinyl chloride material, the lining plate 122 may be a stainless steel sheet, the section of the lining plate 122 in a plane perpendicular to the longitudinal axis Z may be roughly the same with the section of the receiving table 121 in a plane perpendicular to the longitudinal axis Z, and the lining plate 122 and the receiving table 121 together can be fastened to the upper die plate 110 via fixing screws. The lining plate 122 and the receiving table 121 cannot be translated relative to each other by positioning pins at least partially passing in them.

[0044] The lower die assembly 20 of the punching die 1 according to the disclosure will be described below with reference to Figs. 1 to 4.

[0045] As shown in drawings, the lower die assembly 20 also comprises a plurality of separate cutting modules 30, i.e., the plurality of cutting modules are independent to each other, and each of the cutting modules corresponds to one unit of the piece to be cut 90 located between the upper die assembly 10 and the lower die assembly 20. That is to say, when in the punching operation, each of the cutting modules 30 cuts the corresponding unit of the piece to be cut 9 to form independent product units.

[0046] In the present disclosure, the cutting modules 30 each comprise a fixing plate for cutting plate 310 and a cutting plate 320 secured to the fixing plate for cutting plate 310, and a blade 330 is positioned on the cutting plate 320. The fixing plate for cutting plate 310 of each of the cutting modules 30 is slidably supported on the supporting plate, and thus each of the cutting modules 30 is slidably supported on the supporting plate. [0047] Here, “slidably support” means that the supporting plate 220 supports the fixing plate for cutting plate 310 of the cutting modules 30 in the Z direction, and the fixing plate for cutting plate 310 may slide in translation in the XY plane relative to the supporting plate 220. Therefore, each of the cutting modules 30 as a whole is slidably supported on the supporting plate 220. That is to say, the cutting modules 30 is supported on the supporting plate 220 in a manner of being translated relative to the supporting plate 220.

[0048] In the prior arts, even if the piece to be cut has multiple cavities, the cutting plate has a form of whole piece, that is to say, the position of the cutting plate cannot be adjusted for each of the cavities respectively, and the distances between the cutting plate unit for each of the cavity and the center of the wire blade are fixed and un-adjustable. When the units of the product are distributed unevenly, because of, for example, the situation of unstable shrinking due to the hot pressing, it could happen that the product units with uneven dimensions of edges are obtained from the same one piece to be cut during cutting. Compared to the cutting plate with a whole piece in the prior art, the horizontal positions (positions in the XY plane) of the plurality of separate cutting units which can slide relative to the supporting plate can be adjusted when the upper die engages with the lower die, i.e., at that time the cutting modules can slide in translation. Therefore, the problem of the uneven edges (wide and narrow edges) of the product units can be settled very well.

[0049] In the present disclosure, the fixing plate for cutting plate 310 is slidably supported on the supporting plate 220 by means of rolling assembly. The arrangement of the rolling assembly may effectively reduce the friction force between the fixing plate for cutting plate and the support, causing the relative sliding between them easier, that is to say, only small transverse force (force in the XY plane) can cause the cutting modules to slide in translation. Next, the rolling assembly according to the disclosure will be described with reference to Figs. 2 to Fig. 5.

[0050] Fig. 2 to Fig. 4 show an embodiment of the rolling assembly according to the disclosure, i.e. the rolling assembly 50.

[0051] Specifically, Fig. 2 is a schematic perspective view of a portion of parts of the lower die assembly 20 of the punching die 1 according to the present disclosure. It is the situation in which the piece to be cut 90 has three cavities. In Fig. 2, the cutting plate of the cutting module located in the middle is not shown for better showing the details of the structure, and the cutting module rightmost is not shown for better showing an embodiment of the rolling assembly.

[0052] Fig. 3 shows one of the cutting modules 30 and the rolling assembly below an adjacent cutting module (not shown) in a transparent way. Fig. 4 shows the punching die according to the disclosure in a section view, with the section taken along a plane passing through the rolling assembly 50 parallel to the Z direction.

[0053] In the embodiment of Fig. 2 to Fig. 4, the rolling assembly 50 comprises a bailhead plunger, a body of which is mounted within the supporting plate 220 ft and a head 52 of which is lightly higher than the upper surface of the supporting plate 220 to support the fixing plate for cutting plate 310. The head 52 of the bailhead plunger is a rigid sphere, which may be a stainless steel ball. The bailhead plunger may have an internal channel inside, for example a blind hole, in which elastic member such as coil spring can be received, with one end of the spring abutting against a bottom of the internal channel and the other end supporting the head 52 of the bailhead plunger to abut the head 52 against the bottom of the fixing plate for cutting plate 310. When the fixing plate for cutting plate 310 slides relative to the supporting plate 220, the head 52 rolls.

[0054] As shown in drawings, for each of the cutting modules 30, a plurality of rolling assemblies can be provided, which are distributed regularly along the periphery of that cutting module, for example in Fig. 2 and Fig. 3 ft, four rolling assemblies are provided for each of the cutting modules 30 and are located close to the four corners of the rectangular fixing plate for cutting plate for providing uniform supporting force to the cutting module 30, cause it to slide more stably.

[0055] Fig. 5 shows another embodiment of the rolling assembly, i.e. the rolling assembly 50’. As shown in Fig. 5, the rolling assembly 50’ comprises a recess 51’ provided in the upper surface of the supporting plate 220 and a rolling ball 52’ located in the recess 51’. Similar to the head 52 in the first embodiment, rolling ball 52’ may be a rigid sphere. When the fixing plate for cutting plate 310 slides relative to the supporting plate 220, the rolling ball 52’ rolls in the recess 51’.

[0056] By providing rolling assemblies between the upper surface of the supporting plate 220 and the lower surface of the fixing plate for cutting plate 310, a gap is created between the two surfaces, and thus the two surfaces do not contact with each other in a large area, which facilitates the relative sliding between the support and the fixing plate for cutting plate.

[0057] Additionally, in order to limit the extent of the translation of the cutting modules 30 relative to the supporting plate 220, the cutting module 30 further comprises a sliding limit pin 350 which passes through the first cutting plate through-hole 321 (Fig. 6) in the cutting plate 320 and the first fixing plate through-hole 311 in the fixing plate for cutting plate 310, and is fixed to the supporting plate 220. The first cutting plate through -hole 321 and the first fixing plate through-hole 311 may be circular holes, the diameters of them being greater than that of the body of the sliding limit pin 350. The terminal portion 351 (Fig. 6) of the sliding limit pin 350 fixed to the supporting plate 220 may have threads, and the terminal portion 351 is threaded to the threaded hole of the supporting plate 220. Thus, the horizontal moving extent of the cutting modules 30 is determined by the free space between the sliding limit pin and the through-hole, the cutting modules 30 are capable of sliding within a small defined extent relative to the sliding limit pin fixed on the supporting plate 220, causing an effect of “swaying”, and therefore the cutting precision can be adjusted more accurately with the technical effect of improving the precision significantly.

[0058] The cutting modules 30 comprise a plurality of sliding limit pins 350, in the example shown in the drawings, each of the cutting modules 30 is provided with 4 sliding limit pins 350, located respectively in positions close to four comers of a roughly rectangular structure. Thus, the movements of the cutting modules 30 are made steadier.

[0059] The cores 80 according to the disclosure will be described below with reference to the drawings. Specifically, the lower die assembly 20 additionally comprises separate cores 80 corresponding to the separate cutting modules 30, which are mounted on the corresponding cutting plate 310 in a floatable manner. Fig. 7 shows an example in which three cutting modules 30 correspond to three cores 80. Fig. 8 shows a section view of a single cutting module 30 and the corresponding core 80, which section is taken along a plane parallel to the Z direction and passing through the floatable mounting assembly.

[0060] Specifically, the lower die assembly 20 comprises a floatable mounting assembly 810 for the core 80, which comprise a fixing pin 820 and a spring 830. The fixing pin 820 may comprise a first section 821 in the core 80, a second section 822 in the cutting plate 320 and passing through the cutting plate 320, and a third section 823 fixed in the fixing plate for cutting plate 310, wherein the spring 830 is provided around the second section. For each of the cores, two fixing pins 820 may be provided, and they may be mounted in the vicinity of the center of the core 80 to lead to a stable floating operation of the core 80. The first section 821 of the fixing pin 820 may have a diameter-expanded portion which may abut against a recess on the upper surface of the core 80, for providing a stop function for the up and down movement of the core 80. The third section 823 of the fixing pin 820 may have threads, which is screwed into the threaded hole of the fixing plate for cutting plate 310 to achieve the fixation.

[0061] In use, each of the cavities of the piece to be cut 90 covers a core 80. Since the piece to be cut 90 has a stereo shape, it would apply a certain transverse force to each of the cores 80 when covering it. As the fixing plate for cutting plate 310 fixed relative to the core 80 can slide in translation with respect to the supporting plate 220, the transverse force can actuate the corresponding cutting module 30 to translate accordingly, so that, as to this unit of this piece to be cut 90, the horizontal position of the corresponding cutting module 30 is adjusted, and thus the center distances between the cutting modules can be adjusted. That is to say, each unit of the piece to be cut 90 is cut based on its precise center, the problem of uneven edges being settled.

[0062] Further, the piece to be cut 90 contacts the cores 80 with its upper surface, i.e. position with from face. As the cores 80 are floatable, when the upper die assembly presses downwardly, the piece to be cut 90 along with the floatable cores 80 move downwardly, the blades 330 cuts into the piece to be cut 90 from the bottom up, achieving a accurate positioning and a high precision of cutting.