Formed tube with formed wire rivet

A method performed and apparatus formed to fabricate an Isofix latch wire arrangement bends an elongated strip about an open profile to form an elongated tubular member, radially penetrating the member with wires across the open profile, and forming enlarged portions on the legs. The enlargements engage opposite sides of the tube to complete abutment of the strip edges to close the profile and join the wires as rivets to the tubular member formed.

TECHNICAL FIELD

The present invention relates to method and apparatus for reducing time and complexity of producing Isofix child seat restraint anchorages for production original equipment vehicles by combining the formation of the bar with the attachment of latch wires.

BACKGROUND

The production of motor vehicles comprises multiple vertical manufacturing and assembly steps for many of the assemblies or systems contained within a vehicle. Such vertical processing steps substantially increase the cost of producing the vehicle, especially since each part constructed, and the assembly of the parts manufactured into systems, may be accomplished remotely from the subsequent or final vehicle assembly operations. As a result, the more parts and more assembly required to present the assembly for the next or for final assembly into a motor vehicle under automated production conditions could substantially increase the cost of handling and the complexity of final production.

As an example, interior systems such as seating may need to satisfy numerous performance goals. This is particularly true of child seat restraint systems in which a child seat may be restrained by an anchorage system which is assembled to the vehicle chassis or the seating support within the motor vehicle. Not only must such systems restrain a child through various vehicle operating conditions, but such systems must often meet performance and structural standards such as the Federal Motor Vehicle Safety Standards applicable throughout the industry to child seat restraint.

Previous attempts to reduce complexity of structures and processing in the development of seating systems are often related to the particular architecture of a seating or a vehicle structure. Changes in one system often do not provide motivations or suggestions that may be incorporated in others or may not provide cost reduction features in other systems. However, one market segment of seat construction utilizes an Isofix bar. Improvements by manufacturing techniques such as those disclosed in U.S. Pat. Nos. 7,131,693 B2, 6,983,526, and 7,484,800 require separate manufacturing, handling and delivery of tubular bars. These bars have been separately sourced from plants and processes outside the control of the suppliers who may attach latch wires to the tube in order to construct an Isofix bar or fabricate its incorporation with the seating mechanisms of various manufacturers and suppliers to the original equipment vehicle manufacturers. For example, other suppliers' improvements in seating anchorages are also subject to the independent manufacture, handling, adaption and delivery of tubing from others in the manufacture of improved child seat anchorages such as those in U.S. Pat. Nos. 7,721,406 and 6,729,687.

SUMMARY

The present invention overcomes the above mentioned disadvantages by providing a vertically integrated method or apparatus combining tube and rivet assembly. A die formed or roll formed sheet curved to form a tube includes a longitudinal slit that is sealed, at least in part, by rivets. In a preferred embodiment, the rivets are formed by latch wires of the type used for child seat restraints, whose legs may be formed to make collars, and protruding ends that may be enlarged, to abuttingly engage edges of opposed sides of the formed material of the tube extending around a central profile, and securing latch wires to the tube to form latch rings. The rivets can also be inserted through the formed tube in various orientations about the circumference of the tube formed.

As a result, the present invention provides formation of the tube to be employed in structures, for example, Isofix child seat restraint anchorages, by incorporating tube fabrication with the assembly of latch wires or other rivet forming structures. As a result, the present invention may reduce substantial manufacturing and material handling operations that can increase the time and cost of supplying assemblies to manufacturers, and as a result, the time and cost of supplying motor vehicles from [[a]] production assembly operations. A latch ring configuration including the formed tube structure may eliminate welding when providing an alternative clamp mechanism that holds the shape and profile of the tube as desired. In addition, the arrangement and alignment of latch wire rivets may serve to prevent separation at the seam or mating zone of the formed tube's material, and may be adjusted as required to adjust loading requirements upon the assembly.

DETAILED DESCRIPTION

As best shown in the accompanyingFIGS. 3-5, a riveted, formed tube28according to the present invention may be employed where previously known structures have been employed, for example, the child seat restraint anchorage30ofFIG. 1or a known Isofix bar assembly30shown inFIG. 2.FIG. 1displays an environment in which a completed assembly may be employed to meet the structural and performance requirements of Federal Motor Vehicle Safety Standard225and others. A vehicle passenger seat16includes a seat bottom20and a seat back18. The anchorage30carries the latch wires26for positioning of a transverse wire portion at the rear of the seat bottom20and toward the front of the seat back18. A bracket, stanchion, or other part of the seat assembly joins the anchorage to the vehicle14. The child seat10is shown carried by the vehicle seat16so that a pair of child seat latches27are positioned to engage a pair of latch wires26in a well-known manner. Nevertheless, it is to be understood that the technology may be employed in other areas without departing from the present invention.

As also shown inFIGS. 3-5of a preferred embodiment, a cross bar28, generally profiled in the form of a tube23(FIG. 2) of various cross sectional shapes, may be fabricated as a die formed or roll formed sheet22(FIG. 3) is enclosed about an open profile and mated with rivets25. In this preferred embodiment, wires used to form the latch wires26may form the rivets25to fabricate a riveted, formed tube60(FIG. 5). The tube60may also be provided with latch wires26to form an assembly130(FIG. 5).

As shown in the perspective view ofFIG. 2, an Isofix bar30of known type includes an elongated tube23. The tube supports a plurality of latch wires26, preferably in pairs such as70,72,74, that form latch rings when assembled to the tubular member23. Such an assembly may be attached by appropriate means such as brackets36,37that secure the assembly within another structure, for example, the seat assembly, support, or the vehicle body structures46of a vehicle14as generically shown inFIG. 1.

As represented inFIGS. 3-5, one or more rivets25hold the formed sheet tube28(FIG. 4) together. For improved efficiency, the rivets are preferably formed, at least in part, by legs of the latch wires26. Rivets25may extend in opposite or angled directions with respect to each other to demonstrate various angular orientations of the rivets, but may be formed by cold-heading or otherwise modifying the wires. When the legs32and34that extend from a transverse portion31of the latch wire26are used to form the rivet, they may be aligned in the same direction, but each penetration of the tube28may be angularly adjusted as desired. Moreover, oppositely or angularly disposed legs32and34may be positioned as desired depending on load requirements of the assembly or to maintain its integrity, throughout the pairs of latch wires26on the elongated tubular member60(FIG. 5) formed from the rolled sheet28.

The length50of the wire ends38that protrude through the sides of the formed tube may be limited by the use of collars40(FIG. 3), for example, cold headed shoulder42(FIG. 4) received against the opposite side of the formed tube. The length50of the protruding portion38(FIG. 4) may be controlled depending on the width of the gap to be closed at the seam between the edges52and54of the formed tube as shown inFIGS. 3 and 4. The ends38of the protruding portion50may then be formed as collars40, for example, cold-headed as enlarged head58, to close the gap of the seam between the abutting ends52and54of the sheet material forming the tube28by roll forming or other shaping fabrication. An enlarged head58, however enlarged to create a collar40, for example, like cold-headed shoulder42, is made with the protruding end38of the latch wire26, engaging the abutting edges of the formed material28together, while fixedly positioning and securing the latch wires26to form rings along the formed tube60(FIG. 5).

While welding may be eliminated, it is not precluded where combinations of the riveted, formed tube60can be employed, for example, without the concerns of FMVSS standards, or where vehicle styling or customer pleasing finishes may be applied before assembly that may not be incompatible with welding and previously required welding to be eliminated. Alternatively, welding may be added as a step after assembly, or welding may be used to supplement the integrity of the structure where additional strength or alternative load bearing performance must be provided by the assembly.

A method for making a latch ring on an elongated tubular support comprises bending a wire formed with sufficient cross-sectional area to form two legs32and34extending directionally from a transverse portion31spacing the legs from each other. An embodiment may include a process of forming an elongated tubular member60by forming or bends that reorient an elongated strip22of material to position longitudinal edges52and54of the strip22at adjacent positions about an open profile for binding with rivets25. An embodiment may include a structure or process that includes penetrating the latch wire legs32and34into the strip22through the open profile the rolled sheet28encloses, and riveting by forming collars40at opposed sides of the tubular strip28forming the tubular member. An embodiment of a process or structure may include forming enlarged portions40on the legs on the opposed sides of the tubular member at a fixed location along the legs32and34to close any separation between the longitudinal edges52and54, and enclose the profile, fabricating a tube60while securing the latch wire26to the tube60to form a latch ring.

A formed tube60with formed wire rivets25defines an assembly130that comprises a formed sheet28presenting longitudinal edges52and54at adjacent positions about an open profile, and held by a plurality of rivets25. Where the wires are provided by latch wire legs32and34, including a collar portion40, such as cold-headed leg portion42, a protruding portion38of the leg extending across the open profile may be formed as an enlarged head58. When the end38is cold-headed to form head58, the head58forces edges52and54to abut against each other, completing the tube60while the head58and collar40retain the latching wire26on the tube60while positioning the latching portion31for engagement with the latch27. The legs are preferably attached in pairs as latch wires26, and the latch wires26are coupled in pairs, whereby the latch wires26and the tube60form the closed latch rings in an assembly130that may be configured to replace the assembly30ofFIG. 2.