Plastic article or earthenware shaping or treating: apparatus – With means lubricating cooperating apparatus parts
Reexamination Certificate
1999-06-29
2001-03-27
Pyon, Harold (Department: 1722)
Plastic article or earthenware shaping or treating: apparatus
With means lubricating cooperating apparatus parts
C425S326100, C425S336000, C425S384000, C425S388000, C425S392000, C425S396000
Reexamination Certificate
active
06206670
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention concerns an apparatus for the production of transversely ribbed tubes, which has mold jaw halves which bear against each other along a common mold section with first and second front faces and form therebetween a mold passage, wherein each mold jaw half has vacuum passages which are in flow communication with the mold passage, and a cooling passage.
An apparatus of that kind is known for example from EP 0 065 729 A1. In that known apparatus the vacuum passages and the cooling passages open out on the same side of the mold jaw halves so that it is not possible reliably to prevent cooling fluid from passing into the vacuum passages. That can have an effect on operational reliability.
An apparatus for the production of transversely ribbed tubes with mold jaw halves provided with vacuum passages which are in flow communication with a mold passage of the mold jaw halves, the mold passage being formed along a mold section, is also known for example from DE 27 53 297 A1 or U.S. Pat. No 3,981,663.
DE 25 37 184 A1 discloses an apparatus for the production of transversely ribbed tubes, which has mold jaw halves which each have a cooling passage. The cooling passages of the mold jaw halves are in flow communication with cooling conduit loops in order to produce a desired cooling effect for the mold jaw halves.
The applicants' DE 195 17 023 C1 discloses an apparatus for the production of transversely ribbed tubes, having mold jaws which bear closely against each other with their front faces along a common mold section. In that known apparatus, along the common mold section, the mold jaws form at least two spaced-apart mold passages. Each mold passage communicates with associated vacuum passages, while the vacuum passages of adjacent mold passages in each mold jaw are in flow communication with each other through communicating passages. Valve devices in that arrangement serve to provide for a flow communication between the respective mold passage wanted, and a vacuum source.
The object of the present invention is to provide an apparatus of the kind discussed above, with which high-quality transversely ribbed tubes can be produced using structurally simple means, with a high level of productivity.
SUMMARY OF THE INVENTION
In accordance with the invention, in an apparatus of the kind discussed above, that object is attained in that the first front faces of the mold jaw halves are provided with vacuum communication passages which open out at a first surface of the mold jaw halves, that provided at the mold section is a stationary vacuum bar or rail which is in flow communication with the vacuum communication passages of the respective mold jaw halves which are disposed at the mold section, that the cooling passage of the respective mold jaw half has, at a second surface which is different from the first surface, a cooling agent feed means and a cooling agent discharge means, and that provided at the mold section is a stationary cooling agent bar or rail which is in fluid communication with the cooling agent feed means and with the cooling agent discharge means of the respective mold jaw halves which are disposed at the mold section.
The apparatus according to the invention has the advantage that the vacuum connection and the cooling agent connection to the respective mold jaw halves which are at the mold section are provided at surfaces which are different from each other, of the mold jaw halves, so that cooling agent is reliably prevented from unintentionally passing into the vacuum passages, while using structurally simple means. A further major advantage of the apparatus according to the invention is that a sound, reliable flow communication between the vacuum source and the vacuum passages of the respective mold jaw halves which are at the mold section is guaranteed by the stationary vacuum bar or rail and in addition a sound, reliable fluid communication of the cooling passages of the last-mentioned mold jaw halves is guaranteed by the stationary cooling agent bar or rail, wherein the mold jaw halves are movable at a high speed of forward movement, thus resulting in a correspondingly high level of productivity for the apparatus according to the invention.
It has proven to be desirable if, in the apparatus according to the invention, a guide and slide element is fixed to the first surface of each mold jaw half and if each mold jaw half is connected to a support element which establishes the second surface and which is guided along the mold section at the cooling agent bar or rail. It is desirable if the first and second surfaces are disposed in mutually opposite relationship and are arranged in mutually parallel relationship. Such a design configuration affords the advantage that the vacuum connection and the cooling agent connection do not impede or adversely affect each other, but can be arranged without any problems, as desired. Preferably the first and the second surface of the mold jaw halves are oriented horizontally and their front faces are oriented perpendicularly.
The guide and slide element and the support element of each mold jaw half of the apparatus according to the invention preferably comprise the same material. That material is preferably an abrasion-resistant material, for example high-quality steel.
The mold jaw halves preferably comprise a material which has a high coefficient of thermal conduction. That material is for example aluminum. Such a design configuration not only results in the individual mold jaw halves being of a relatively low overall weight, so that the drive power for producing the forward feed movement of the mold jaw halves can be correspondingly reduced, but it also results in optimum cooling for the mold jaw halves, which also has a corresponding positive effect on the operational reliability and the productivity of the apparatus according to the invention as well as on the quality of the transversely ribbed tubes produced with the apparatus according to the invention.
So that the apparatus according to the invention can be used with mold jaw halves for producing transversely ribbed tubes of different dimensions, it is desirable if the mold jaw halves can be connected to the associated support elements by means of quick-action clamping devices. When using quick-action clamping devices of that kind, it is possible, with a concomitant saving of time, to fix the respectively wanted mold jaw halves of a set of mold jaws for transversely ribbed tubes of given dimensions to the support elements of the apparatus according to the invention, so that thereafter the apparatus when equipped in that fashion can be used to produce the desired transversely ribbed tubes.
In order to compensate for dimensional tolerances of the mold jaw halves, which often cannot be avoided, and in order to compensate in particular also for thermal expansion phenomena in respect of the mold jaw halves, it is preferred if, in the apparatus according to the invention, the vacuum bar or rail is elastically yieldingly mounted to a stationary vacuum head.
The cooling agent bar or rail preferably has a central cooling agent circulation portion and two oil-lubricated guide portions laterally adjoining same. In that arrangement, the oil-lubricated guide portions desirably comprise an abrasion wear-resistant metal and the central elongate cooling agent circulation portion comprises a sliding or bearing metal alloy. Said metal may be high-quality steel while the bearing metal alloy may be bronze.
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Bachman & LaPointe P.C.
Heckenberg Donald
Pyon Harold
UNICOR GmbH Rahn Plastmaschinen
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