WO1999036244A1

WO1999036244A1 - Auxiliary injection assembly with removable support

Info

Publication number: WO1999036244A1
Application number: PCT/IB1999/000057
Authority: WO
Inventors: Giuliano Rivi
Original assignee: System Sate S.R.L.
Priority date: 1998-01-19
Filing date: 1999-01-18
Publication date: 1999-07-22
Also published as: AU1778499A; ITRE980007A1; IT1304262B1

Abstract

By means of a removable support (2), with magnetic base (3), an auxiliary injection assembly (1) assumes a condition of interchangeability, thanks to which it can be easily and advantageously used, depending on utilization requirements, on different main moulds (8) for plastic materials in general. Its removable condition also facilitates its positioning and/or orientation with respect to the type of main mould whereto it is coupled each time. Said auxiliary injection assembly (1) can be of the traditional electro-hydraulic type, but with the hydraulic actuation of the injection piston branched off connection of the main mould, or it can be of the electromechanical type, with the injection piston controlled by a motorised lead nut/worm screw assembly (20).

Description

Auxiliary Inπection Assembly with Removable Support

Technical Field

The present invention relates to an auxiliary injection assembly with removable support, for complementary moulding injections of plastic items with at least two components. The auxiliary injector is provided with a removable support with magnetic base thanks to which its interchange and oriented positioning on the mam moulds for plastic materials, whereto they can be coupled, are rapid and easy. The injection assembly can be of the traditional electro-hydraulic type, but the actuation of the injection piston is not taken off the hydraulic unit of the moulding machine or from its own dedicated hydraulic unit, but rather is taken off any connection of the main mould itself. Alternatively, the actuation of the injection piston can be provided by a simple electromechanical motorised lead nut/worm screw assembly.

Background Art

It is well known that plastic items realised with the moulded combination of at least two components with different characteristics, are currently formed in different ways; in particular, and the most common use, to form ma components with predominant volume or weight, ma moulds are adopted wherein the plastic material to be formed is injected directly by the moulding machines, whereas for the injection of the second plastic material component, or components, m the same mam mould, auxiliary injectors are adopted which operate at subsequent times and which, depending on space and/or work requirements, are located n the adjacent areas of the machines themselves, with constraints thereon or on structures suitably and/or necessarily dedicated its closest proximity. In other solutions, to the moulds for the formation of the mam components, applied to moulding machines, are fastened rigid support means suitable for directly support q the auxiliary injectors necessary for the formation of the specific second component or components. However, although the aforementionea solutions do allow to form items made of plastic material with at least two components, they nonetheless present some drawbacks. In particular, the best suited placement of the auxiliary injectors on the mouldirg machines, or n the areas adjacent thereto, entails considerable wastage of time, production and labour, without even excluding the possibility of subsequent interventions for adjustments and/or corrective modifications. Conversely, although positioning the auxiliary injectors on the fixed brackets available on the mam moulds themselves does allow to reduce the aforesaid time wastage, it can nonetheless create overly rigid structural solutions, not versatile, and unsuitable for particular applications, for instance those destined to machines located m restricted environments. Such applications are m any case limiting with respect to the possibility of using the same injectors on different moulds, to obtain different kinds of items. In any case, the aforesaid solutions the hydraulic controls for moving the pistons actuating the auxiliary injectors are either taken off independent, dedicated hydraulic units, which are definitely costly, or are taken directly off the hydraulic units of the moulding machines, through specific connections.

Disclosure of Invention

The aim of the present invention is to eliminate the aforesaid drawbacks. The invention, as it is characterised by the claims, solves the problem by means of an auxiliary injection assembly with removable support, through which the following results are obtained: each auxiliary injector is fastened on a support, which may be capable of being oriented, provided with a magnetic base; the injection piston control, although it can be compatible with currently used systems, can preferably and more economically be obtained with a different hydraulic system from cαrrent ones, or by an electromechanical system: the hydraulic system is branched off any connection of the mam mould; the electro-mechanical system instead comprises a motonsed lead nut/worm screw assembly, totally independent from the other controls.

The advantages attained by means of the present invention essentially consist of the fact that the magnetic base support allows the easy and rapid application of the auxiliary injectors on any kind of ma mould, their better orientation as a function of the available space and of the adjacent structures, and allows an equally easy and rapid disassembly both for any maintenance operations and for the possible application on other mam moulds, to form different plastic items with two or more components. Other advantages stem from the fact that, with a simple branching on the hydraulic circuit of any one of the connections of the main moulds, it is possible to realise the direct electro-hydraulic control of the actuating piston of each auxiliary injector assembly, without significant additional costs and/or unwarranted interventions to modify the existing structures. Alternatively, and as an additional advantage, the actuator piston of the auxiliary injector assemblies can be controlled with an electromechanical system, comprising a motonsed lead nut/worm screw set, totally separate and independent from the controls of all other organs present.

The invention is described m detail hereafter, according to its embodiments provided purely by way of non limiting example, with reference to the accompanying drawings, wherein:

- Fiqure 1 shows the schematic view of an auxiliary injector assembly provided with fixed support, with magnetic base,

- Figure 2 shows the same auxiliary injector provided with a support capable of being oriented, with magnetic base, Figure 3 schematically shows an auxiliary injector assembly with fixed support with magnetic base, applied to a mam mould,

- Figures 4 and 5 show a partial section of a mould for items made of plastic material with two components, m the sequential phases of injection of the mam component with predominant volume or weight, directly oy means of tne moulding machine, and injection of the second component, by means of an auxiliary injector, - Figure 6 schematically shows an auxiliary injector controlled by means of an electromechanical lead nut/worm screw device, and

- Figure 7 shows the dedicated hydraulic diagram, combined to any connection of the mam mould, for controlling the hydraulic piston actuating the traditional auxiliary injectors .

The figures show an auxiliary injection assembly with removable support which substantially comprises an auxiliary injector (1) that is fastened to a support (2) fitted with a magnetic base (3) . The engagement of the injector (1) to the support (2) can be of the fixed type or of the type capable of being oriented. In the second case, the support can essentially comprise a dual articulation lockable in the desired position after orientation, wherein, for instance, the auxiliary injector is fastened to a plate (4) , rotating around a horizontal pivot fulcrum (5) engaged to a fork (6) , whilst the latter is rotatorily engaged to the magnetic base (3) , by means of a vertical pivot fulcrum (7) . In any case, by means of the magnetic base (3) each auxiliary injector (1) can easily be fastened on any peripheral side (18) of any mam mould (8) , to form items made of plastic material with at least two components, m correspondence with any dedicated flat surface (9), straight or inclined, where a connection

(10) is provided for the injection of a second plastic component (11) . Figures 4 ana 5 show, m sectic , the two subsequert phases of moulding of a mam part (12), combined, also by moulding, with a second plastic component (11) . The first phase entails the internal carriages (13) in closed position, to delimit the space related to the formation of the part (12, alone; after injection through the connection (14) and the conduit (15), and at the end of the first forming process, the carriage (16) is made to move back so that the space (11'), adjacent to the ore wherein the mam part has already bee¹- moulded, is freed. Through the conduit (17), connected to the space (11') and coraomed to the connection (10), the auxiliary injector (1) injects the material to form the second plastic component (11) .

As is well known, the internal carriages of the moulds (8), such as the ones indicated as (13), (16) and the like, are moved hydraulically through specific circuits, also included m the same moulds. According to the present invention, in the same way, and m a very simple and economical manner, the control of the hydraulic pistor actuating the auxiliary injectors (1) of a traditional type, adopted to form the second plastic components, is taker directly off the hydraulic circuit of any one of the branches present, dedicated to the actuation of the aforesaiα carriages. Figure 7 shows an example of embodiment of a hydraulic circuit, specifically devoted to the aforesaid task, interconnected with the oil pathways (21) of any branch of the jacks actuating the moulds; the dedicated circuit comprises a three-position solenoid control valve (22) , and a two-position solenoid valve (231 to control the injection pressure. Witn the solenoid valve (22) centrally positioned, as in the figure, the dedicated circuit of the auxiliary injector (1) is excluded and the fluid feeds m a traditional manner an-, branch present on a rnoulα. Once the ma injection is completed, the solenoid valve (22) is actuated to be aligned with its right part, still with reference to the figure, ana the fluid obtained from tne pathways (21 ^ is used to actuate the piston controlling the screw, or Archimedean screw, of the auxiliary injector. The two-position solenoid valve (23) remains m the conditions indicated in the figure for pressurised injection, for a pre-set, programmed time, whereupon it is actuated to slide rightwards, according to the fiqure, to regulate the last injection phase with reduced and differentiated pressure, as a function of the pre-set requirements. At the end of the auxiliary injection phase, l . e . at the end of the charge produced by the piston actuated by the screw of the auxiliary injector, the three-position solenoid valve (22) is actuated to align it with its left part to invert tne flow, thereby causing the injection piston to return, with related return of the screw and with the suction of excess product from the conduits (17).

Alternatively, if the mam moulds (8) are to be rendered totally independent and separate from the auxiliary injectors (1) , the actuating system of the auxiliary injectors themselves, instead of the hydraulic type as traditional ones currently m use, can be realised with electromechanical means, or corresponding ones. Figure 6 shows an auxiliary injector (1) provided with an electrical control motor (19) combined with a lead nut/worm screw reducer (20) , wherein the worm screw itself constitutes the injection control stem. Whilst the present invention has been described and illustrated according to its embodiments provided purely by way of non limiting example, it will be readily apparent to those versed in the art that various modifications to the shapes, the details, the components, the configurations of the various solutions, to the control means and to the assemblies may be made, without tnereoy departing from its scope and purpose.

Claims

Cia ms

1. Auxiliary injection assembly (11 for complementary injections to form items made of plastic materials witn at least two components characterised in that it is provided with removable support (2) w th magnetic base (3) .

2. Auxiliary injection assembly (1) for complementary injections to form items made of plastic materials with at least two components according to claim 1 characterised in that the removable support (2), fitted with magnetic base (3), is of the fixed type or is of the type that can be oriented.

3. Auxiliary injection assembly (1^ for complementary injections to form items made of plastic materials with at least two components according to claims 1 and 2 characterised m that the hydraulic piston commanding the injector (1) is actuated by the hydraulic circuit of any branch of the mam mould (8) whereto the injector itself is temporarily associated.

4. Auxiliary injection assembly (1) for complementary injections to form items made of plastic materials with at least two components according to claims 1 and 2 characterised m that the injection command of each injector is directly actuated by the worm screw of a reducer (20) with electric motor (19), directly connected with the injector itself, in total independence and separation from the commands present on the ma mould (8) whereto the auxiliary assembly is temporarily associated.