RU2810812C1 - Injection mould for manufacturing pallets and pallets produced by injection mould - Google Patents

Abstract

FIELD: injection moulding.

SUBSTANCE: invention relates to the field of injection moulding technology for pallets, namely, to an injection mould for producing pallets from a polymer material and pallets manufactured using the said mould. The injection mould contains an upper movable and lower fixed half-mould, the latter being made with a replaceable insert that forms part of the working cavity with the possibility of forming a solid or cellular geometry of the load-bearing surface of the pallet, and the upper half-mould has movable form-building elements forming part of the working cavity with the possibility of forming supporting, inner and side surfaces of the pallet.

EFFECT: improved efficiency of pallet production, as well as the performance properties of manufactured pallets through simplified design, increased accuracy of geometric parameters, stability and rigidity of the structure, while simultaneously reducing material consumption.

9 cl, 13 dwg

Description

The present invention relates to the field of injection molding technology for pallets, namely, to injection molds for the production of pallets made of polymer material intended for storing and moving products for industrial, technical and household purposes by placing them on the outer horizontal surface of the pallet.

Currently, the market places high technical demands on the quality of polymer pallets, in particular on the combination of such technical parameters as increased lightness and high mechanical rigidity of the structure, which together should ensure the reliability of the product and ease of use. This is achieved due to the presence of a complex cellular configuration of the pallet consisting of longitudinal and transverse stiffeners located in a certain way, which can be oriented in horizontal and vertical directions.

As a rule, polymer pallets are made by injection molding, which is carried out in injection molds consisting of two halves - a matrix and a punch, which, when closed, form a working cavity for forming the finished product, into which, through a special channel located in the body of the matrix or punch, a melt of polymer material is supplied under high pressure, which then solidifies and forms the finished product. Similar technical solutions are known, in particular, from invention patent DE102004044063 (B3), utility model patents CN 207374896 (U), CN 213769400 (U), CN 216784186 (U).

The main disadvantage of these technical solutions is the impossibility of forming polymer pallets with a complex cellular structure in the working cavities of injection molds.

This disadvantage is partially eliminated by using separate injection molds for the components of the pallet, followed by a connecting operation to form a permanent connection.

In particular, from the patent for the invention US 96157010 (A) a polypropylene pallet is known, including an upper surface in the form of a load-bearing base and a lower surface having an upper horizontal part with a through cellular structure formed by multidirectional stiffeners, some of which intersect with each other under different corners, as well as supports arranged in three longitudinal rows, equipped with longitudinal support bridges and made integral with the upper horizontal part. The top and bottom surfaces of the known pallet are manufactured by injection molding in separate molds, after which the finished surfaces are connected to each other by welding.

The disadvantages of the known technical solution are the complexity of producing a pallet, due to the inability to manufacture the product using a single injection mold, which increases the complexity of the technological process, as well as the insufficiently high quality and accuracy of the geometric parameters of the finished product due to possible plastic deformations of the polymer material at the welding and inaccurate relative orientation of the connected parts.

However, a common disadvantage of all the above-mentioned known pallets is the impossibility of producing several pallets using a single injection mold, which significantly reduces production efficiency.

The purpose of the invention is to develop the design of an injection mold for the production of pallets from polymer material, eliminating the disadvantages of known technical solutions, as well as polymer pallets manufactured using this mold with increased performance properties.

The technical results to be achieved by the invention are to increase the efficiency of production of pallets, as well as improve the performance properties of manufactured pallets by simplifying the design, increasing the accuracy of geometric parameters, stability and rigidity of the structure, while reducing material consumption.

To achieve the above technical results, an injection mold for the manufacture of pallets is proposed, containing an upper movable half-mold and a lower fixed half-mold, having parallel parting planes that, when closed, form a working cavity with molding surfaces, while the lower half-mold is equipped with a gating system for supplying the polymer material of the pallet into the working cavity and is made with a replaceable insert that forms part of the working cavity with the possibility of forming a continuous or non-continuous geometry of the load-bearing surface of the pallet, and the upper half-form has fixed and movable form-building elements that form part of the working cavity with the possibility of forming the supporting, internal and lateral surfaces of the pallet, with In this case, the fixed form-building elements are made with the possibility of forming a continuous geometry of the side surface of the pallet and the non-continuous geometry of the supporting and internal surfaces of the pallet, and the movable form-building elements are made with the possibility of forming a non-continuous geometry of the side surface of the pallet.

In this case, in particular variants of the design of the injection mold:

- the gating system for supplying polymer material may include at least thirteen supply channels spaced along the surface of the replaceable insert of the lower half of the mold;

- the mold may have hidden channels for cooling the polymer material, passing inside the upper and lower halves of the molds;

- movable forming elements can be equipped with a hydraulic drive;

- the upper half of the mold can be equipped with a mechanical system for pushing out the pallet casting, including rod pushers and a moving part of the forming elements that are stationary in the mode of forming the discontinuous geometry of the supporting and internal surfaces of the pallet;

- polypropylene or polyethylene can be used as the polymer material supplied to the working cavity of the pallet.

The specified technical results are also achieved by the fact that the pallet, manufactured in the proposed injection mold using a replaceable insert that forms part of the working cavity with the possibility of forming a continuous geometry of the load-bearing surface of the pallet, contains a rectangular load-bearing base made with a solid outer surface, as well as supports, located in three spaced longitudinal rows and interconnected in rows by longitudinal support bridges, equipped with longitudinal stiffening ribs on the side of the supporting surface, while the inner surface of the base and supports has a cellular structure formed by the intersection of longitudinal and transverse stiffening ribs, and the supports have on the lateral side the surfaces are vertical recesses, and the side surface of the base between the supports is made with longitudinal cells formed by vertical stiffeners located at equidistant intervals, as well as the outer and inner surfaces of the base.

The specified technical results are also achieved by the fact that the pallet, manufactured in the proposed injection mold using a replaceable insert that forms part of the working cavity with the possibility of forming a non-continuous geometry of the load-bearing surface of the pallet, contains a rectangular load-bearing base having a cellular structure formed by perforations, as well as supports , located in three spaced apart longitudinal rows and interconnected in rows by longitudinal support bridges, equipped with longitudinal stiffening ribs on the side of the supporting surface, while the inner surface of the base and supports has a cellular structure formed by the intersection of longitudinal and transverse stiffening ribs, and the supports have on the side the side surface has vertical recesses, and the side surface of the base between the supports is made with longitudinal cells formed by vertical stiffeners located at equal intervals, as well as the outer and inner surfaces of the base.

The essence of the invention is illustrated by the following figures of the drawings:

- Fig. 1 – injection mold, general view;

- Fig. 2 – matrix with visible cooling channels, general view;

- Fig. 3 – injection mold with a collapsible insert into the matrix, general view;

- Fig. 4 – injection mold with visible cooling channels for the insert into the matrix, general view;

- Fig. 5 – sprue bushing with a wound heating element, sectional view;

- Fig. 6 – injection mold, sectional view;

- Fig. 7 – matrix with replaceable insert, general view;

- Fig. 8 – punch with form-building surfaces, general view;

- Fig. 9 – movable punch blocks, general view;

- Fig. 10 – pallet casting ejection system, general view;

- Fig. 11 – perforated polymer tray, general top view;

- Fig. 12 – perforated polymer tray, general view from below;

- Fig. 13 – solid polymer pallet, general top view.

The injection mold 1 (Fig. 1) is a complex mechanical device designed to produce perforated 2 (Fig. 11, 12) and solid 3 (Fig. 13) polymer pallets using injection molding technology. Polypropylene or polyethylene is preferably used as the polymer material of the pallet. Mold 1 (Fig. 1) consists of a lower fixed half-mold - matrix 4 and an upper movable half-mold - punch 5, which have internal form-building surfaces that, when closed, form a working cavity for forming a pallet.

Guide blocks 10, 11 (Fig. 3, 8), as well as fixed 12 and movable 13 plates (Fig. 10), located at some distance from each other to form intermediate longitudinal 39 and transverse 40 grooves (Fig. 9). In the side parts of the punch there are two movable blocks 14, 15 (Fig. 3, 8), forming the side walls of the pallets 2, 3. The punch is also equipped with an ejection system (Fig. 10), consisting of movable plates 13 and rod pushers 16, designed for pushing the pallet casting out of the punch. In this case, the movable blocks 14, 15 and movable plates 13 are driven by a hydraulic drive system containing hydraulic cylinders 45 (Fig. 6) of the movable plates 13 and hydraulic cylinders (not shown in the drawings) of the movable blocks 14, 15 associated with the corresponding movable elements , a hydraulic pump (not shown in the drawings) connected to the working stroke chambers of the hydraulic cylinders through channels for hydraulic fluid (not shown in the drawings), as well as shut-off valves (not shown in the drawings), each of which is connected to the corresponding hydraulic cylinder. The system for pushing out the rod pushers 16 is structurally connected to the movable plates 13, on which the pushers are in turn attached. The pushers are driven by an external hydraulic cylinder of the injection molding machine (TPA) (not shown in the drawings).

The die 4 has a hot runner gating system consisting of thirteen gating channels 17 (FIGS. 3-6) heated by spiral heating elements 46 (FIG. 5) wound around a hot runner sleeve 47. When turned on, each heating element 46 is heated and heats the sleeve 47 with the polymer material inside, which, after melting to a viscous-flow state, is fed through the gating channels 17 through nozzles 18 into the working cavity of the mold formed by closed parallel planes of the matrix 4 and punch 5 connector. To change the configuration of the mold cavity, allowing alternatively, to produce one of two types of plastic pallets 2, 3 on one equipment, replaceable steel inserts are used - a relief insert 19 (Fig. 3, 7) and a flat insert 20 (Fig. 3, 6), each of which forms an independent part of the working cavity mold and is attached to the matrix 4 using fasteners 21 (Fig. 6). In the preferred design of the matrix 4, the replaceable inserts 19, 20 are made collapsible and are assembled, for example, from five rectangular blocks 44 (Fig. 3). In this case, particular variants of the matrix 4 are possible, in which the blocks belonging to the insert 19 are mounted together with blocks having a flat surface, in a sequence depending on the customer’s requirements for the finished pallet, which allows to significantly expand the range of manufactured products.

Using a relief replaceable insert 19, a polymer pallet 2 is formed (Fig. 11, 12), which is a one-piece product of complex configuration. Pallet 2 contains a supporting base 23.1, having a cellular structure (Fig. 11), formed by perforations 24 to achieve a given rigidity and load capacity while reducing the total weight of the product in direct contact with the cargo placed on the pallet, supports 25 (Fig. 12), designed to accommodate the upper part at a given location from the surface, and longitudinal support bridges 26, located between the supports 25, and equipped with longitudinal stiffeners 34, which increase the rigidity of the entire structure and strengthen the supports. On the inside (Fig. 12) the base 23.1 has a complex cellular structure formed by the intersection of longitudinal 27 and transverse 28 stiffeners. This leads to an increase in the longitudinal and transverse rigidity of the base. All supports 25 also have an internal cellular structure formed by the intersection of longitudinal 29 and transverse 30 stiffeners. This leads to an increase in the longitudinal and transverse rigidity of the base. Along the perimeter of the base, on the outer side of the pallet, there are eight side projections 31, which serve as stops for the cargo placed on the base and prevent it from slipping during storage or transportation. The supports 25 have external recesses 32 that form depressions on the surface, which serve to increase the torsional rigidity of the supports. On the sides, the walls of the pallet between the supports have a cellular structure formed by transverse ribs 33, as well as the outer and inner surfaces of the base 23.1, which increases the rigidity and load-carrying capacity of the pallet.

Using a flat replaceable insert, a pallet 3 is formed (Fig. 13), which differs from pallet 2 by a continuous outer surface of the base.

The punch 5 and the matrix 4 with replaceable inserts 19, 20 are equipped with a polymer material cooling system, consisting of many hidden cooling channels drilled into them and having different configurations, in particular, channels 6.1 (Fig. 2) with end pipes 7.1 and channels 6.2 (Fig. 4) with end pipes 7.1, forming independent cooling circuits for the working cavity. In this case, the corresponding end pipes of the cooling channels are connected to flexible coolant inlet/outlet hoses extending outside the mold, in particular, hoses 8.1 (Fig. 7) and 8.2 (Fig. 8). Part of adjacent cooling channels can communicate with each other using flexible tubes 9.1 (Fig. 7) and 9.2 (Fig. 8).

The mold is also equipped with temperature sensors 22 (Fig. 2) and position sensors for the movable plates (not shown in the drawings). Temperature sensors 22 allow you to regulate the temperature of the supplied material, since the temperature of the melt of the material has a significant impact on the quality of the resulting product).

The technological process of manufacturing polymer pallets using the proposed injection mold is considered using the example of pallet 2 (Fig. 7, 8) and is carried out as follows.

Mold 1 is installed on a injection molding machine of a universal design (see, for example, the Internet link https://haitian.ru/termoplastavtomaty/haitian-jupiter-iii/). A relief replaceable insert 19 is manually attached to the matrix 4 using fasteners 21 (Fig. 7). After this, the injection molding machine closes the mold in such a way that the matrix 4 and the punch 5 are clearly closed and fixed in a closed position by means of the angular guide columns 35 of the punch 5 (Fig. 8), included in the reciprocal grooves 36 of the matrix 4 (Fig. 7), which made in its shaped side part 43. The guide blocks 10, 11 of the punch 5 are adjacent to the side part 43 of the matrix 4 along its entire internal contour. Moreover, before closing the mold, the hydraulic drive system drives the movable blocks 14, 15 (Fig. 8), located on the sides of the punch 5, which move perpendicular to the opening axis of the mold to a position corresponding to the design of the side walls of the pallet, forming together with the blocks 10, 11, plates 12, 13 of the punch 5 and a replaceable insert 19 of the matrix 4 working cavity of the mold. Then, through the inlet pipe 37 (Fig. 6) of the matrix 4, a melt of polymer material is supplied under high pressure, which enters through the gating channels 17 and through the nozzles 18 (Fig. 5) is injected into the working cavity of the mold. In this case, spiral heating elements 46 ensure that the required temperature of the supplied material is maintained in the range from 180 to 280 degrees.

When the volume of the mold cavity is filled with a melt of material, the material goes around the protrusions 38 of the insert 19 of the matrix 4 and fills the recesses 41 located along the perimeter, resulting in the formation of the outer surface of the base 23.1 of the pallet 2 (Fig. 11) with perforations 24 and side protrusions 31. At the same time, the material fills the longitudinal 39 and transverse 40 inter-tile grooves (Fig. 9), which have different depths, resulting in the formation of the geometry of the pallet on the inside (Fig. 12), including longitudinal 27 and transverse 28 ribs of the base 23.1, longitudinal 29 and transverse 30 ribs rigidity of the supports 25, supporting surfaces of the jumpers 26 with longitudinal stiffeners 34. In this case, the guide blocks 10, 11 ensure the formation of a continuous geometry of the side surface of the pallet with external recesses 32, and the forming surfaces 48, 49 (Fig. 9) of the movable blocks 14, 15 - a cellular structure formed by the vertical ribs 33 and the base surfaces 23.1, as well as holes 42 designed to grip the pallet with the teeth of a forklift.

Next, coolant (thermostatic water or oil) is passed through the hidden water channels 6 of the matrix 4 and similar channels of the punch 5 through flexible hoses 8. As a result, the material cools for a given time in the mold cavity, hardens and forms the finished product - pallet 2. Upon completion of the process, the injection molding machine opens the injection mold, as a result, the punch 5 moves away from the matrix 4 to the required distance, after which the hydraulic drive system drives the movable blocks 14, 15, which extend perpendicular to the opening axis of the mold to their original position. Then the ejection system begins to work (Fig. 6, 10) and the pushers 16 with movable plates 13 simultaneously move forward, separating the pallet 2 from the walls of the punch 5, which is immediately picked up by the grip of the robot installed on the injection molding machine. Thus, the movable plates 13 perform a double function - they are used as forming surfaces, as well as elements of the casting ejection system, which generally expands the operational capabilities of the mold.

Mechanically, the manufacturing process of pallet 3 (Fig. 13) is similar to that described above. In this case, a replaceable insert 20 is used, which has a flat working surface (Fig. 6) with recesses located along the perimeter, similar to recesses 31.2. The insert 20 is pre-attached to the matrix 4 in a similar manner to the insert 19 using fasteners 21. In this case, during the formation of the outer surface of the base 23.2 of the pallet, the material flows freely over the entire surface of the insert 20, filling the recesses located along the perimeter that form the side projections 31.2 of the pallet.

Thus, the distinctive features of the proposed injection mold are the ability to create a complex configuration of the cellular structure of pallets due to the design of the moving blocks, as well as the ability to change the configuration of the pallet without changing the injection mold. For this purpose, replaceable single or collapsible inserts are used in the matrix, which can be changed manually, depending on orders for a specific product. This results in significant savings in tooling costs, since the production of two pallets would require two injection molds of a traditional design.

The purpose of the invention is to develop the design of an injection molding press
molds for the production of pallets from polymeric material, eliminating
disadvantages of known technical solutions, as well as manufactured ones
through this mold of polymer pallets with increased
operational properties.

Technical results aimed at achieving
invention is to increase production efficiency
pallets, as well as improving the performance properties of manufactured
pallets by simplifying the design, increasing accuracy
geometric parameters, stability and rigidity of the structure, with
while reducing material consumption.

To achieve the above technical results,
An injection mold for producing pallets is proposed, containing
upper movable half-mold and lower fixed half-mold,
having parallel parting planes, forming when closed
working cavity with molding surfaces, while the lower
the half-mold is equipped with a gating system for supplying polymer material
pallet into the working cavity and is made with a replaceable insert forming
part of the working cavity with the possibility of forming a continuous or
cellular geometry of the load-bearing surface of the pallet, and the upper half-mold
has fixed and movable formative elements that form
part of the working cavity with the possibility of forming a supporting, internal and
side surfaces of the pallet, while the fixed forming
elements are designed to form a continuous geometry
side surface of the pallet and non-continuous geometry of the supporting and internal
surfaces of the pallet, and the movable form-building elements are made
with the possibility of forming a non-continuous geometry of the side surface
pallet

At the same time, in particular variants of the design of the casting
Press forms:

Claims (9)

1. An injection mold for the production of pallets, containing an upper movable half-mold and a lower fixed half-mold, having parallel parting planes that, when closed, form a working cavity with molding surfaces, while the lower half-mold is equipped with a gating system for supplying the polymeric material of the pallet into the working cavity and is made with a replaceable insert that forms part of the working cavity with the possibility of forming a solid or cellular geometry of the load-bearing surface of the pallet, and the upper half-mold has fixed and movable form-building elements that form part of the working cavity with the possibility of forming the supporting, internal and side surfaces of the pallet, while the fixed form-building elements made with the possibility of forming a continuous geometry of the side surface of the pallet and a non-continuous geometry of the supporting and internal surfaces of the pallet, and the movable form-building elements are made with the possibility of forming a non-continuous geometry of the side surface of the pallet. 2. The mold according to claim 1, characterized in that the gating system for supplying polymer material includes at least thirteen supply channels spaced along the surface of the replaceable insert of the lower floor of the mold. 3. The mold according to claim 1, characterized in that it has hidden channels for cooling the polymer material, passing inside the upper and lower floors of the molds. 4. The mold according to claim 1, characterized in that the movable forming elements are equipped with a hydraulic drive. 5. The mold according to claim 1, characterized in that the upper half of the mold is equipped with a mechanical system for pushing out the pallet casting, including rod pushers and a moving part of the forming elements, stationary in the mode of forming the discontinuous geometry of the supporting and internal surfaces of the pallet. 6. The mold according to claim 1, characterized in that the insert of the lower half of the mold is collapsible. 7. The mold according to claim 1, characterized in that polypropylene or polyethylene is used as the polymer material supplied to the working cavity of the pallet. 8. A pallet manufactured in an injection mold according to claim 1, characterized in that it contains a rectangular load-bearing base having a cellular structure formed by perforations, as well as supports located in three spaced apart longitudinal rows and interconnected in the rows by longitudinal support bridges , equipped with longitudinal stiffening ribs on the side of the supporting surface, wherein the inner surface of the base and supports has a cellular structure formed by the intersection of longitudinal and transverse stiffening ribs, and the supports have vertical recesses on the side surface, and the side surface of the base between the supports is made with longitudinal cells, formed by vertical stiffeners located at equal intervals, as well as the outer and inner surfaces of the base. 9. A pallet manufactured in an injection mold according to claim 1, characterized in that it contains a rectangular load-bearing base made with a continuous outer surface, as well as supports located in three spaced longitudinal rows and interconnected in the rows by longitudinal support bridges, equipped with longitudinal stiffening ribs on the side of the supporting surface, while the inner surface of the base and supports has a cellular structure formed by the intersection of longitudinal and transverse stiffening ribs, and the supports have vertical recesses on the side surface, and the side surface of the base between the supports is made with longitudinal cells formed vertical stiffeners located at equidistant intervals, as well as the outer and inner surfaces of the base.