Plastic and nonmetallic article shaping or treating: processes – Mechanical shaping or molding to form or reform shaped article – Shaping against forming surface
Reexamination Certificate
1998-11-17
2001-05-22
Heitbrink, Jill L. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Mechanical shaping or molding to form or reform shaped article
Shaping against forming surface
C264S334000, C425S556000, C425S577000, C425SDIG005, C029S890127
Reexamination Certificate
active
06235231
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a process for production of shaft passages in a plastic-molded part, the mold, and use of the process of production in a flap device, for example, for a feed system of internal combustion engines.
BACKGROUND OF THE INVENTION
Known in feeds for internal combustion engines are air intake pipes with pivoting flaps such as, for example, those taught by Patent Application EP 0 701057. This document teaches a pipe which for each combustion chamber comprises at least two air ducts, at least one of which is selectively closed by a flap that pivots around a shaft that is crosswise to the duct between an at least partially sealing position and a position for opening the duct. In this kind of device, according to the prior art, the metal-flap actuating shaft is mounted in the molded thermoplastic part that constitutes the body of the pipe with journals and rings that require gaskets to ensure the sealing of the shaft at the junction with the plastic parts.
In such a device, the rings can be equipped with flexible or elastically deformable means to limit the radial play of the shaft relative to the body of the thermoplastic device.
Taking into account this possible play, issues of alignment of shafts and of rotation of the shaft relative to the plastic part are dealt with by the additional parts. This has the drawback of requiring the production and installation of additional parts in the thermoplastic part. A first drawback is the increased production cost. In addition, this composition makes it necessary to provide hoods, mounting points, journals and barrels that can be attached to the main part by ultrasonic soldering or by locking. This latter solution does not necessarily ensure that the axis of rotation will be maintained properly relative to the body of the device.
In a variant embodiment of this prior art, the common drive shaft is flexible and comprises duplicate-molded drive segments that are separated by flexible portions. This flexibility facilitates installation by making it possible to compensate for the major misalignments of the cradles and barrels that form the bearings and the range of rotation of the various flaps. The problem of misalignment of the bearings is therefore known, and to date one skilled in the art has not found a satisfactory solution.
Today, to solve the problem of alignment of passages of pins in the successive bearings, several other solutions exist, but each of them has its drawbacks. To obtain the anticipated result, which is to be able to engage a rotating pin freely in the various bearings of a part that follows the same shaft, it is necessary that the passage holes be perfectly aligned if it is desired that this pin be able rotate freely. To do this, it is possible to duplicate-mold a pin that is then withdrawn; this leaves open the possibility of a non-alignment existing after the pin has been withdrawn owing to deformations due to internal tensions. It is also possible to pierce the part over its entire length. Considering the lengths in question, this leads to buckling of the drill, which does not make it possible to ensure perfect alignment. In any case, the machining embrittles the surface that is attacked by the drill. Finally, a last solution that corresponds to that of the European Patent is to study the part to produce it in several parts so that the bearings can be assembled in the molded part.
SUMMARY OF THE INVENTION
This invention has as its first object to solve this problem of aligning the bearings in a plastic molded part by means of a new production process.
This object is achieved by the fact that the process of producing the shaft passages in a molded-plastic part that at regular intervals comprises bearings for a shaft that is intended to actuate at least two moving parts that are attached to the shaft at given sites, whereby said shaft bearings are placed in the molded plastic part at sites that correspond to each side of the sites of moving parts, characterized in that said solution consists of providing a recess by the advance of a slide of the molding tool between two adjacent bearings that are each associated with the sites of different moving parts, and forming a bearing portion of each side of the sites of each moving part by a moving wedge relative to a slide, whereby the wedge carries a pin that is intended to form a bearing part of one side of the moving part.
According to another particular feature, the pin is integral with the wedge, which is interchangeable.
According to another particular feature, the pin can be adjusted and interchanged.
According to another particular feature, the pin is mounted in a cylindrical housing of the wedge with a cylindrical stud that is offset relative to the axis of symmetry of the pin and is immobilized in the desired position to ensure the alignment of the bearings with the other pins of the other wedges by attachment means that can be removed.
Another object of the invention is to propose a use of the process of the invention in the field of inlet systems for internal combustion engines.
This object is achieved by the fact that the process is used for the production of a flap device that is intended to be placed between the cylinder head and an air distributor system for internal combustion engines, whereby the distributor comprises a number of air ducts that are intended to empty into the combustion chambers, whereby the flap device makes it possible to reduce the air passage or passages between the distributor and the combustion chamber or chambers by the pivoting of the flaps, characterized in that the flap device comprises a molded plastic device body in which, from each side of each of the passages in which the flaps are placed, the bearings are formed directly in a single operation by molding, whereby said bearings of two different passages that are associated with two different flaps are separated by a recess.
According to another particular feature, the device is a flap flange that comprises a number of air passages that are separated from one another by a number of recesses, whereby the bearings are formed in the walls that are adjacent to the passages and to the recesses and a second injector passage empties into each of the passages that are below the plane that contains the shaft of the flaps, and parallel to the plane of the cylinder head.
According to another particular feature, the flange comprises chords that form two parallel planes that delimit the two ends of the passages, whereby these chords are equipped with insert attachment housings, whereby said inserts are threaded for the attachment of the distributor and are not threaded for the passage of the attachment bolts of the flange on the cylinder head.
According to another particular feature, the face of the chord that comprises the non-threaded inserts and is oriented toward the cylinder head is equipped with peripheral grooves in the passages to receive a seal.
According to another particular feature, the face of the chord opposite the distributor comprises an extension shaped like a half-shell that is intended to receive either a pneumatic lung for controlling the rotation of the shaft of the flap by negative pressure or an electrical system for controlling the rotation of the flap.
According to another particular feature, the flange is integrated into the manifold.
Another object of the invention is to propose a mold for production of shaft passages in a plastic part.
This object is achieved by the fact that the mold for production of shaft passages in a plastic part, characterized in that it comprises moving cores that are intended to form at least two passages in the part; at least one slide that controls the movements of two moving wedges that are integral with slides that are mounted to slide crosswise in the mold relative to the direction of vertical movement of the slide; whereby the movements of the moving wedges and the slides are controlled by respective pins that are placed on each side of the slide and oriented in two opposing angular directions
Heitbrink Jill L.
Mecaplast Sam
Nixon & Vanderhye P.C.
LandOfFree
Process for production of shaft passages in a molded plastic... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for production of shaft passages in a molded plastic..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for production of shaft passages in a molded plastic... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2519127