Metal working – Method of mechanical manufacture – Assembling or joining
Reexamination Certificate
2002-01-08
2004-08-24
Hong, John C. (Department: 3726)
Metal working
Method of mechanical manufacture
Assembling or joining
C029S432000, C029S432100, C029S432200, C029S715000
Reexamination Certificate
active
06779244
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a method for producing a windshield wiper bracket of U-shaped cross section, with two through holes disposed in the legs of the bracket, through which a rivet extends.
The invention also relates to an apparatus for producing windshield wiper bracket of U-shaped cross section, where the apparatus includes folding means for producing a U-shaped profile from a flat bracket blank provided with two through holes, a positioning mechanism for sliding a rivet slug into the through holes, which are aligned with each other after production of the U-shaped profile, and deformation means for producing at least one rivet head on the rivet slug, according to the preamble to claim
8
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Methods for producing a windshield wiper bracket of U-shaped cross section are known. With these known methods, a U-shaped bracket, whose two legs are provided with through holes that are aligned with each other, is formed in a first station. In a second station, a rivet slug is inserted through the two mutually aligned through holes in the U-shaped bracket in such a way that a free end of the rivet slug protrudes out from the corresponding through hole of the bracket. Then in a separate work cycle, the respective end of the rivet slug is wobbled to form a rivet head. This method for producing a U-shaped bracket with a rivet is relatively complex and time-consuming.
It is also known to provide a bracket, which is U-shaped and suitably embodied, with a roll rivet. In order to produce a roll rivet, the legs of the U-shaped bracket are disadvantageously weakened by means of suitable excisions so that an undesirable fracture of the roll rivet connection on the bracket can occur during operation of the windshield wiper. The roll rivet breaking off from the bracket like this can, for example, be caused by an occurrence of material fatigue. This known method for producing a U-shaped bracket while forming a roll rivet is also disadvantageously complex and time-consuming.
SUMMARY OF THE INVENTION
The method according to the invention includes the following steps:
production of through holes in a flat bracket blank;
insertion of a rivet slug into one of the through holes;
folding of the legs to produce the U-shaped profile and to thereby position of the rivet slug in a position aligned with the other through hole;
sliding of the rivet slug into the position extending through both of the through holes, and
riveting of the rivet slug.
By inserting a rivet slug into one of the two through holes of a flat bracket blank before the folding of the legs, it is possible to bring the rivet slug into the desired position aligned with regard to the two through holes while simultaneously producing the bracket with the U-shaped cross section. It is also possible to execute the sliding of the rivet slug into the position that extends through both through holes, together with the folding of the legs and the positioning of the rivet slug in one continuous work step by means of a single, suitably embodied tool. The production of a bracket with a U-shaped cross section while forming a rivet can consequently take place in a single manufacturing or processing station.
Preferably, the rivet slug is fixed in position in the bracket blank. This assures that the rivet slug is disposed in a definite position before and during the folding of the legs to produce the U-shaped profile of the bracket. Is also possible to use preassembled flat bracket blanks, each provided with the rivet slug fixed in position, in order to produce brackets with U-shaped cross sections for windshield wipers.
In order to fix it in position, the rivet slug is advantageously pressed into the through hole of the flat bracket blank, forming a press fit. A position fixing of the rivet slug in one of the two through holes of the bracket blanks by means of a press fit can be produced simply and reliably from a production engineering standpoint. The strength of the press fit between the rivet slug and bracket blank can be adapted with relative ease to each intended application, i.e. depending on the wall thickness of the bracket blank and the diameter of the rivet slug. As a result, in particular the method steps of sliding and riveting of the rivet slug can be controlled and/or adjusted in a reliable and effective manner. Furthermore, using a press fit to fix the position of the rivet slug assures that after the folding of the legs and during the sliding of the rivet slug, it aligns exactly with the other through hole and no shifting of the rivet slug in relation to the through holes occurs, which would hinder the sliding of the rivet slug.
Preferably by means of an entry bevel in operational contact with a rivet edge, the rivet slug is pushed into the other through hole of the U-shaped bracket until the rivet slug protrudes out from the through holes with its ends. Because of the definite starting position (press fit) of the rivet slug in one of the through holes of the bracket blank, it is possible after the folding of the legs, to easily and reliably slide the rivet slug out of its initial position into the end position extending through both of the through holes. In this connection, it is particularly important that the rivet slug protrudes out from the through holes in the end position so that it is possible to produce rivet heads (riveting of the rivet slug). From a production engineering standpoint, an entry bevel is relatively easy and inexpensive to produce in a corresponding manufacturing tool.
According to a preferred embodiment, the ends of the rivet slug protruding out from the U-shaped bracket are plastically deformed by means of a wobbling process to form a respective rivet head. From a process engineering standpoint, it is particularly favorable to form rivet heads on the free ends of the rivet slug protruding out from the through holes of the bracket with the U-shaped cross section, preferably simultaneously by means of a wobbling process. As a result, the bracket with the U-shaped cross section, with the rivet slug disposed in the aligned position, can maintain its original position and does not have to be brought into a special and/or new working position for the formation of the rivet heads. A wobbling process for producing a rivet head is particularly advantageous with regard to a correct and controllable material deformation on the corresponding rivet slug end. The desired and/or necessary exertion of force and consequently the material deformation for producing the rivet head can be adapted to each intended application by suitably varying the wobbling process (deformation force, adjustment angle, wobbling speed).
Advantageously, the two ends of the rivet slug are plastically deformed simultaneously. The formation of both of the ends protruding out from the through holes of the bracket into respective rivet heads permits a rapid and effective rivet production on the bracket with the U-shaped cross section.
Advantageously, the rivet slug is stabilized in its shaft part between the legs during the plastic deformation of the two ends. This effectively prevents the rivet slug from buckling during the production of the rivet heads. It is consequently easily possible to produce a correct and particularly stable rivet connection between the legs of the bracket.
According to the invention, the apparatus is characterized in that the folding means, the positioning mechanism, and the deformation means are disposed in a single processing station. The production of a bracket with a U-shaped cross section and a rivet contained in it in a single processing station is particularly favorable from a production engineering standpoint because this eliminates the transport time and/or waiting time that would otherwise occur during the manufacturing process. Furthermore, a folding of the legs, and a sliding and riveting of the rivet slug in a single processing station permits a bracket to be produced with relative ease while fulfilling particularly high precision requirements since the manufacturing tolerances in the bracke
Bijnens Marc
Criel Paul
Hong John C.
Robert & Bosch GmbH
Striker Michael J.
LandOfFree
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