Plastic article or earthenware shaping or treating: apparatus – Female mold and charger to supply fluent stock under... – With means to close mold
Patent
1995-04-07
1996-12-17
Heitbrink, Tim
Plastic article or earthenware shaping or treating: apparatus
Female mold and charger to supply fluent stock under...
With means to close mold
425592, 425593, B29C 4564
Patent
active
055851266
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention deals with a closing unit for form or mold tools of injection molding machines with a stationary mold support- or base plate, a mold support plate whose spacing relative to the stationary mold support plate can be changed by displacement, as well as a drive support plate, which is connected to the stationary mold support- or base plate by traction links, for instance struts, which can simultaneously be used as a slide guidance for the mobile mold support plate. An electromotor is used as an actuation or control drive for the mobile mold mounting plate, which can be alternatingly repositioned between a folded or kinked state and a stretched state by means of a threaded spindle and one or several toggle lever systems, which toggle lever system or systems are installed between the drive support plate and the mobile mold mounting plate, and this indeed in such a way that the molding tool is retained under closing tension between the two mold carrier plates in the stretched position of the toggle lever system or systems.
A closing unit of this known type is for instance disclosed in the EP-A1 0 164 419. The particularity of this known closing device consists in that the electric servomotor serving as an actuation drive for the mobile mold mounting plate is to be operated in the stretched position of the toggle lever system or systems by a current, which is lower than the normal working current. Solely by means of this, thus without using stops, the stretched position of the toggle lever system or systems holding the molding tool between the two mold carrier plates under closing tension is to be assured in this state of the art. In the known closing unit it is however not only disadvantageous, that the electric servomotor has to carry current also in the stretched position of the toggle lever system or systems, even if it is only a reduced current. Rather discrepancies arise therefrom, in that the electric servomotor and/or the toggle lever system or systems actuated by said motor as force transmittal mechanism must be given an unsymmetrical arrangement relative to the closure unit.
SUMMARY OF THE INVENTION
In order to eliminate this shortcoming in state of the art closure units, the invention provides, the threaded spindle is axially displaceable by means of a nut, which spindle engages at the toggle lever system or systems in a non-rotatable manner thereto.
The advantage of this configuration of a closure unit is, that its entire drive- and force-transmittal system can be built up in a flush position with or symmetrically to the force axis of same and therefore can be laid out in a very compact manner.
The use of a liquid-cooled electric servomotor is not only of advantage because same can be given a minimum constructional size, rather it is also significant, that during stoppages very high torques can be generated herein, by means of which the stretched position of the toggle lever system against stationary stops can be optimally secured. The heat energy dissipated from the electric servomotor by the water as a cooling agent can be recovered and subsequently made use of for instance for tool tempering or heat treatment. Thus an increase of the overall efficiency of the injection molding machine or a saving of energy costs is achieved.
The proposal in the invention has also proved itself, to couple the nut allocated to the threaded spindle within the drive support plate to the hollow shaft of the servomotor. It has also proved itself to connect the threaded spindle with a crosshead engaging at one or a plurality of toggle lever systems so as to be non-rotatable thereto.
Closure units of this generic type are as a rule equipped with a device for tool installation height change allocated to the two mold support plates. This means, that adjustment devices exist, by means of which the spacing between the stationary mold support- or base-plate and the displaceable mold support plate can be varied without being affected by the toggle lever systems used as force transmitt
REFERENCES:
patent: 5102327 (1992-04-01), Reinhart
patent: 5176923 (1993-01-01), Ito
patent: 5362222 (1994-11-01), Faig et al.
patent: 5417558 (1995-05-01), Heindel et al.
Bleier Harald
Heindl, deceased Friedrich
Battenfeld Kunststoffmaschinen Ges.m.b.H.
Heitbrink Tim
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