Background of the Invention Field of the Invention This invention relates to hinge arms and hinges. In one of its aspects, the invention relates to hinge bearings for articulated hinges for motor vehicle hoods, trunk lids, doors, lift gates, or the like, wherein hinge arms have one or more molded hinge bearings for reception of rivets that pivotably interconnect the arms. In another of its aspects, the invention relates to a hinge arm having openings which are accurately spaced from each other. In another of its aspects, the invention relates to a method for making hinge arms having accurate placement of pivot holes and accurate bearing thicknesses. Description of the Related Art

Articulated hinges in motor vehicle hoods, trunk lids, doors, etc., are typically constructed in a single pivot joint or multiple pivot joints having at least one arm, wherein each arm includes a pair of spaced bearings for pivotal connection with other arms of the hinge assembly. During the manufacturing process, the arms are stamped into a particular shape and holes are formed in the arms at predetermined locations. A bearing having a centrally located hole is aligned with a hole in one of the arms, and a hole in another of the arms is aligned thereover. A rivet is then passed through the aligned holes and set such that the arms are pivotally connected together. Although the stamping operation is very efficient in forming the arms, it is difficult to obtain a high degree of tolerance required for thickness, hole diameter and placement. In addition, the surfaces around the holes are naturally distorted by the manufacturing process. Generally, the stamping process does not account for variations in metal thickness. Inaccuracies in hole size, placement, metal thickness and surface variation may result in hinge assemblies which exhibit unsatisfactory operation

or unacceptable dimensional deviations. Even if the holes are properly sized and placed, separate positioning of each bearing and rivet during assembly is time consuming.

Summary of the Invention These and other problems of the prior art are overcome by insert- molding a bearing in hinge arms in articulated hinge assemblies for motor vehicle hoods, trunk lids, lift gates, doors or the like.

According to the invention, a hinge arm includes opposed surfaces and an opening extending through the hinge arm between the surfaces. A bearing extends through the opening and is molded directly to the hinge arm, such that a portion of the bearing is formed over the opposed surfaces to prevent separation of the bearing from the hinge arm.

In one embodiment, a second opening extends through the arm between the opposed surfaces and is spaced from the first opening. A second bearing extends through the second opening and is molded directly to the hinge arm in the same manner as the first bearing. Preferably, the hinge arm is elongate and has opposite ends. Each opening is formed proximal to one of the ends and each bearing is molded around one of the ends.

According to a further embodiment of the invention, each bearing includes an aperture extending therethrough for receiving a fastener to thereby pivotally mount the hinge arm to spaced support members. In the place of apertures, according to an even further embodiment of the invention, a fastener can be inserted into one or more of the arm openings during the bearing molding operation to integrally form the fastener to the hinge arm. During the arm forming operation, the diameter of each opening in the arm, the distance therebetween, arm surface variation and material thickness may be formed with relatively large tolerances. Such dimensional deviations are automatically

compensated for during insert-molding of the bearings, since the diameter of each bearing opening or fastener and the distance therebetween, as well as any deviation in the arm surfaces and thickness are fixed in the mold. Thus, the spacing between bearing openings or fasteners, the diameters thereof, and the bearing surfaces and material thickness of the arm remain constant from arm to arm, even when these variables change from arm to arm. A greater amount of tolerance in the metal forming process is therefore made possible, which results in the rejection of fewer parts and the reduction of manufacturing expense, when compared to the separate bearing and arm arrangement of the prior hinge assemblies. The integrally molded bearings also result in shorter assembly time, when compared to the prior hinge assemblies.

According to a further embodiment of the invention, a hinge assembly of the type used on an automotive hood, trunk lid, door, or the like, has first and second members pivotally connected to each other through a pivot joint. Each of the members has opposed surfaces with an opening extending between the first and second surfaces. The pivot joint includes a bearing extending through the opening of the second member and integrally molded thereto. A portion of the bearing is formed over the opposed surfaces of the second member to prevent separation of the bearing therefrom. A fastener extends at least through the opening of the first member and is in rotational contact with the bearing for pivotally connecting the first and second members together.

A method of forming a hinge arm according to the invention includes shaping the hinge arm from blank stock material to form a first hinge arm surface and a second opposing hinge arm surface; forming a first opening in the hinge arm between the first and second surfaces; inserting the hinge arm into a mold cavity; and injecting a molten thermoplastic resin into the mold under heat and pressure to at least partially fill the opening and cover at least a portion of the first and second surfaces adjacent to the opening to thereby form an

integrally molded bearing on the hinge arm. When the first opening is formed proximal to an end of the hinge arm, the bearing material is injected around the end of the hinge arm as well. The thermoplastic or thermosetting resin can be any suitable bearing material. An aperture can be formed in the bearing for receiving a fastener to thereby pivotally mount the hinge arm to a support member. In an alternative embodiment, a fastener is inserted into the hinge arm opening before the injecting step and a molten thermoplastic resin is injected around the fastener in the opening to pivotally attach the fastener to the hinge arm. In a preferred embodiment of the invention, a second opening is formed in the arm and spaced from the first opening, and a thermoplastic molten resin is injected into the mold cavity into the second opening and around at least a portion of the first and second surfaces adjacent to the second opening to thereby form a second integrally molded bearing on the hinge arm. An aperture can be formed in each of the spaced bearings for receiving a fastener to thereby pivotally mount the hinge arm to a support member. The distance between centers of the bearing apertures is formed independent of the distance between centers of the hinge arm openings due to the fixed shape of the mold.

In an alternative embodiment, a fastener is accurately placed into each hinge arm opening before the injecting step and molten thermoplastic resin is injected around the fastener in the openings to pivotally attach the fasteners to the hinge arm. Each opening in the arm has an inside diameter greater than an outside diameter of the fastener. Insert molding of the fasteners in the bearing openings more precisely positions the distance between centers of the fasteners than the distance between centers of the hinge arm openings. The thermoplastic resin is preferably injected simultaneously into the first and second openings.

These and other objects, features and advantages will be apparent from the ensuing description taken in conjunction with the accompanying drawings.

Brief Description of the Drawings The invention will now be described with reference to the drawings in which:

FIG. 1 is a top plan view of a hinge arm with integrally molded bearings according to the invention;

FIG. 2 is a cross-sectional view of the hinge arm and integrally molded bearings taken along line 2-2 of FIG. 1 ;

FIG. 3 is a cross-sectional view of the molded bearing and integrally retained rivet according to a second embodiment of the invention;

FIG. 4 is a left side perspective view of a completed hinge assembly incorporating the integrally molded bearings; and FIG. 5 is a right side perspective view of the completed hinge assembly of FIG. 4.

Detailed Description of the Preferred Embodiments

Referring now to FIGS. 1 and 2, a hinge arm 10 includes insert molded bearings 12 and 14 for pivotal connection to other hinge arms and/or torsion bars (not shown) as part of a hinge assembly for a motor vehicle trunk, lift gate, or hood closure mechanism, etc. The arm 10 is preferably stamped from a sheet of metal, such as steel or aluminum, and has formed at either end holes 16, 18 around which the bearings 12, 14 are molded. Each bearing 12, 14 is preferably injection molded from a fiberglass reinforced plastic and includes an opening 20, 22 that is dimensioned to receive a rivet 24 (shown in dashed line

in FIG. 2). A suitable bearing material is nylon 6/6 containing PTFE and glass fibers for reinforcement. During the arm forming operation, the diameter of each hole 16, 18, the distance therebetween, and material thickness may be greater or less than the desired dimensions. Such dimensional deviations are automatically compensated for during the molding operation, since the distance between each bearing opening, their diameter and thickness are fixed in the mold. Thus, the distance between bearing openings 20, 22 and their diameter remain constant from arm to arm, even when the spacing and diameter of the holes 16, 18 vary from arm to arm. A greater amount of manufacturing tolerance is therefore made possible, which results in the rejection of fewer parts and the reduction of manufacturing expense, when compared to the separate bearing and arm arrangement of the prior art. The integrally molded bearings also result in shorter assembly time and less labor for hinge assemblies, when compared to the prior hinge assemblies. As an alternative to separately installing the rivet 24 in each bearing opening 20, 22, the rivet 24 can be positioned in each arm opening 16, 18 and the bearings 12, 14 are insert-molded on both sides of the arm and into the arm openings around the rivets to form an integrally molded arm, rivet and bearing assembly. In this manner, assembly time and labor can be further reduced.

With reference now to FIG. 3, a hinge arm with a modified bearing arrangement is illustrated, wherein like parts in the previous embodiment are represented by like numerals. As in the previous embodiment, a hinge arm 10' includes a modified bearing 12' that is insert-molded therewith. The bearing 12' includes a rivet 24 that is retained therein through a shoulder 25 that is formed as an integral part of the bearing. During the molding operation, the rivet and arm are placed in a mold in their respective positions and the bearing material is insert-molded around the arm and rivet. After the molding operation, the rivet

forms a tight fit with the bearing material and is rotatable with respect thereto.

This construction further reduces the amount of hinge parts and the amount of assembly time, since the rivet is now an integral part of the bearing arrangement.

Although FIG. 3 illustrates a single bearing 12', it is to be understood that the bearing 14 in the first embodiment can be modified in like manner.

As shown in FIGS. 4 and 5, a hinge assembly 30 comprises a mounting plate 32 pivotally attached to a lid securing plate 34 through a pair of hinge arms 36, 38. The hinge arms 36, 38 are identical to either of the hinge arms 10, 10' described above, with the exception that the arm 36 is shorter that the arm 38 and includes a stop tab 39 that abuts the arm 38 when the hinge is in the fully open position.

The securing plate 34 is L-shaped and includes a first leg 40 and a second leg 42. The first leg 40 is formed with a pair of spaced apertures (not shown) for receiving a pair of rivets 24 located at either end of each hinge arm 36, 38. The second leg 42 is also formed with a pair of spaced apertures 44 sized for receiving a pair of fasteners (not shown) in order to attach the hinge assembly

30 to a vehicle lid.

The mounting plate 32 includes a first leg 46 and a pair of flanges

48 that extend at approximately a 90° angle with respect thereto. The first leg 46 has a pair of spaced apertures (not shown) for receiving the rivets 24 located at either end of each hinge arm 36, 38. A pair of spaced apertures 50 are formed on the flanges 48 and are sized for receiving a pair of fasteners (not shown) in order to attach the hinge assembly 30 to a vehicle.

In the first embodiment, the hinge assembly 30 is assembled by first inserting a rivet 24 into each bearing opening 20, 22 in the arms 36, 38. The rivets 24 are then inserted into openings in the securing plate 32 and mounting plate 34. The distal ends of the rivets are then deformed in a well known rivet setting operation to secure the arms to the plates.

In the second embodiment, the rivets are already integrally molded to the arms during the bearing forming operation. Thus, the step of inserting the rivets into the bearing openings is eliminated. The distal ends of the rivets are then inserted into openings in the securing plate 32 and mounting plate 34 and the rivets are set to connect the arms to the plates. If an initial bond is formed between the rivets and bearings during the molding operation, the bond is readily broken when the arms are rotated with respect to the plates 32, 34 for the first time. Thus, the rivets are rotatable with respect to the bearings, and are stationary with respect to the securing plate 32 and mounting plate 34. Reasonable variation and modification are possible within the spirit of the foregoing specification and drawings without departing from the scope of the invention.