DE2132432A1 - Multi sprue injection unit - with variable sprue positions - Google Patents

Abstract

A variably adjusted multi-point sprue system for thermoplastic injection or foaming machines comprises a number of sprue units each consisting of a disc with an eccentric nozzle aperture, rotatably mounted in an eccentric hole in another disc, so that the nozzle aperture can be set at any position within a given circumference. The arrangement enables a large number of different moulds, requiring different sprue positions, to be served thus effecting a saving in sprue heating equipment.

Description

File number Variably adjustable machine-bound multi-point sprue system for thermoplastics Uie invention relates to a multi-point sprue system, which is an integral part of the injection molding or foam molding machine for thermoplastic Plastics is. The four sprue nozzles are variably adjustable in the fixed machine mounting plate and thus enable multiple injection in any shape, through this variably adjustable machine-bound sprue system is not required in the injection or Foam molds the heated hot runner gate and thus an undesired increase in temperature the form. In addition, this casting system aims at a simple, inexpensive mold construction and a functionally reliable controllable injection.

Today's technology shows an injection molding machine on which there is an axially movable mass cylinder with an injection nozzle. This injection nozzle is connected through an opening in the fixed machine plate drove the shape.

For large injection molded or foam parts, for those made of injection molding Reasons several sprue points are necessary, a sprue distributor with the corresponding many sprue nozzles built into the mold. To prevent the distribution channels from freezing, these are usually heated or made so large that the channel core also remains fluid with long cycle times or shorter downtimes. This supply of heat must now be broken down by good insulation and additional cooling. To this Runner with injection nozzles, which must be built to fit in every shape, belongs also the installation of the heating, as well as the thermal sensor and possibly the hydraulic one Vüsen lock. The machine thus takes over the processing of the plastic compound and the shape of the distribution and keeping warm of the mass from the machine nozzle to the respective injection point.

It is therefore necessary to have an individual runner for each mold with spray nozzles to build and install which the injection molding or foam mold considerably more expensive and the mold installation height increased by 15 - 25 @@.

The invention is based on the object of the material flow of the plastic mass from preparation in the mass cylinder to injection into the bore cavity bring a unit together to create a hot runner gate that is used for as many forms as possible.

According to the invention, this object is achieved in that, as shown in FIG e.g. 4 sprue nozzles in two eccentrically mounted turntables, the lie in the fixed machine plate, any arbitrary point in a certain Can approach the radius of action.

The invention is illustrated by Fig. 1 in a schematic cross section, through Fig. 2 in plan. In the fixed machine plate (1) are arbitrary a lot, e.g. four rotatable discs (2) embedded. This disc (2) is eccentric in turn a rotatable disc (3) embedded, in which again eccentric a nozzle hole with a centering hole is located. Since the pitch circle (6) the hole in the disc (3) intersects the center point (23) of the disc (2), the nozzle (4) can be used to approach any point within the pitch circle (5) This mobility of e.g.

four injection nozzles (4) is sufficient to cover approx. 9o - 95% of all shapes, that are suitable for a specific machine. For the forms that not injected with this variably adjustable machine-bound hot runner gate can be, by removing the retaining piece (7) and the disc (8) the hole for the machine nozzle t15) free, so that, as usual, with a can be worked in the 1? form built-in hot duct sprue.

The nozzle (4) and the injection molding (9) can be of any shape are used, whereas the distribution pipes t with clamped-on ring heaters (11) Som mold makers are made to a precise length and supplied have to.

The mold immersion depth of the nozzle (4) should as far as possible for every mold be the same. By adjusting the pressure nut (12) and vary of the spacer (13), the immersion depth of the nozzle (4) can be a certain amount Dimension can be adjusted. The nozzle (4) consists of two tubes, one inside the other, between which a heater (16) is installed. A Hing (14) is attached to the outer tube as counter pressure for the pressure nut (12) and a butt joint (17) for the Connection of the distribution pipe tlo) welded on. In the middle of the inner tube can be a well-known in specialist circles, actuated by a small hydraulic cylinder (18) Needle lock can be installed.

The two rotating disks (2) and (3) are on the basket support surface plans with the fixed machine plate (1) The desired nozzle position is made with the help of an angular graduation (21) and isonius (22) set with a hand crank (19). To make setting easier, a tool label is attached to each forw, on which you can see which degree setting is set for each disc got to. The oche disks (2) and (3) are determined using the on the Üorm (24) located centering rings (20). which grip into the centering bores of the washers (3).

Claims (1)

File number Patent claim Variably adjustable machine-bound multi-point sprue system for thermoplastic injection molding and thermoplastic foam molding machines, characterized in that that the discs (3) with an eccentrically arranged nozzle bore are themselves eccentric are rotatably mounted in the discs (2), which in turn are rotatable in the fixed ; «Machine plate (1) lie. The pitch circle (6) described by the Jüsenbohrung must be on Cut the discs 3) the center point (23) of the discs (2). L e r s e i t e