Wiper arm assembly having a locking catch

A wiper arm assembly and method of assembly thereof includes a mounting head and a wiper arm configured for relative rotation during assembly from a disassembled position to a shipping position, wherein the wiper arm and mounting head are locked against rotation toward the disassembled position once in the shipping position. The mounting head and wiper arm have locking surfaces configured for locked engagement with one another while in the shipping position. The locking surfaces are brought into engagement with one another by a force imparted by a spring while rotating the mounting head relative to the wiper arm from the disassembled position toward the shipping position. When in the shipping position, the locking surfaces confront each other and prevent the mounting head and the wiper arm from rotating back toward the disassembled position from the shipping position.

BACKGROUND OF THE INVENTION

1. Technical Field

This invention relates generally to wiper arm assemblies for vehicles, and more particularly to wiper arm assemblies having a mounting head for attachment to a vehicle and a wiper arm attached for articulation relative to the mounting head, and methods of assembly thereof.

2. Related Art

Wiper arm assemblies for vehicles are known to have a wiper arm hinged for articulation relative to a mounting head. The mounting head facilitates attachment of the assembly to a surface on the vehicle so that a wiper blade attached to the wiper arm is suitably positioned for oscillation against a window. The wiper arm and wiper blade attached thereto can generally be articulated relative to the mounting head away from the window to a service-up position to facilitate replacing the wiper blade.

It is known to manufacture wiper arm assemblies with the mounting head and wiper arm permanently fixed to one another by a staked pin or rivet. In this type of construction, the pin or rivet is assembled between axially aligned openings in the mounting head and wiper arm, and then the pin or rivet is fixed therein to permanently couple the parts together sot that they can not be taken apart thereafter. At some point in assembly, one end of a coil spring is attached to the mounting head, and an opposite end of the coil spring is attached to the wiper arm. The force imparted by the coil spring maintains the wiper blade in wiping engagement with the window as the mounting head is oscillated by a drive motor. The spring also allows the wiper arm to be articulated away from the window by manually lifting the wiper arm, such that the wiper blade can be serviced, as necessary. Though this type of wiper arm assembly works well in use, it typically comes with increased cost in manufacturing and assembly due to the added cost associated with the pin or rivet and the processes for permanently fixing the mounting head and wiper arm together.

It is also known to manufacture wiper arm assemblies with the mounting head and wiper arm attached to one another such that they can be disassembled from one another after being assembled in a “preassembled” position. A preassembled position is defined when the mounting head and wiper arm are attached together, but not yet assembled to a vehicle. In one known construction, as disclosed in the prior art section of U.S. Pat. No. 6,553,608 (the '608 patent), the mounting head and wiper arm are attached together under a preload of a tension spring, with an axle on one of the parts being received to form a hinged connection in an open hub of the other part. Bearing surfaces on the mounting head and wiper arm are pulled into engagement with one another along a line of force imparted by the tension spring. The opposing reaction forces between the bearing surfaces act to maintain the mounting head and wiper arm in the preassembled position until the wiper arm assembly is fully assembled to a vehicle. Unfortunately, the bearing surfaces are not prevented from moving back toward a disassembled direction and can slide relative to one another under a minimal force, which can occur during transport or during careless handling, whereupon the mounting head and wiper arm can become inadvertently disassembled.

To combat the problem of inadvertent disassembly set out in the prior art section of the '608 patent, the '608 patent teaches forming the bearing surfaces as being arranged to define interacting camming surfaces. In order for the mounting head and wiper arm to be disassembled from their preassembled position, the bearing surfaces require the spring attaching the mounting head and the wiper arm to be increased in length, thus requiring an increased tensile force to be overcome prior to the parts becoming disassembled from one another. Upon the bearing surfaces overcoming a cam lobe, the point at which the tensile spring is at its greatest length, the length of the spring is allowed to decrease, thereby causing a tensile force imparted by the spring to disassemble the mounting head and the wiper arm from one another. Accordingly, the '608 patent teaches that the mounting head can still be disassembled from the wiper arm by rotating the wiper arm relative to the mounting head toward the disassembled direction with a sufficient torque to overcome the cam lobe.

SUMMARY OF THE INVENTION

A wiper arm assembly has a mounting head and a wiper arm for relative rotation therewith, wherein the wiper arm and mounting head are locked against disassembly upon be assembled to a shipping position. The mounting head has one of an axle or a hub, while the wiper arm has the other of the axle or hub, wherein the hub has a pocket with an open end for receipt of the axle for oscillation therein. The mounting head has one end configured for attachment to a vehicle and an opposite end with a first locking surface extending therefrom. The wiper arm has opposite sidewalls with a second locking surface extending laterally outwardly from at least one of the sidewalls. A spring is arranged for operable attachment to the mounting head and the wiper arm. The locking surface on the wiper arm is configured for engagement with the locking surface on the mounting head under a force imparted by the spring while rotating the mounting head relative to the wiper arm from a disassembled position toward a shipping position. The locking surfaces confront each other while in the shipping position and prevent the mounting head and said wiper arm from rotating back toward the disassembled position from the shipping position.

Another aspect of the invention provides a method of assembling a wiper arm assembly. The method starts with providing a mounting head and a wiper arm. The mounting head is provided having one of an axle or a hub, with the hub be configured with an open pocket for receipt of the axle for rotation therein. The mounting head is further provided with one end configured for attachment to a vehicle and an opposite end having a first locking surface extending therefrom. The wiper arm is provided having the other of the axle or hub and having opposite sidewalls with a second locking surface extending laterally outwardly from at least one of the sidewalls. Then, attaching a spring to the mounting head and the wiper arm, and rotating the mounting head and the wiper arm relative to one another from a disassembled position toward a shipping position and causing the spring to initially increase in preload and the axle to be received in said hub. Next, snapping the locking surfaces on the mounting head and the wiper arm into engagement with one another and into the shipping position under a force imparted by the spring during the rotating step, whereupon the locking surfaces prevent the mounting head and the wiper arm from rotating back toward the disassembled position.

According to yet another aspect of the invention, another method of assembling a wiper arm assembly from a disassembled position to a shipping position is provided. The method includes providing a wiper arm having a locking surface; a mounting head having a locking surface and a spring. Then, attaching the spring to the wiper arm and the mounting head and imparting a preload in the spring by rotating the wiper arm and the mounting head relative to one another. Next, bringing the locking surfaces of the wiper arm and the mounting head into snapping engagement with one another under the preload of the spring, wherein the preload maintains the locking surfaces in confronting abutment with one another while in the shipping position and prevents the wiper arm and the mounting head from being rotated back toward the disassembled position.

Accordingly, a wiper arm assembly constructed in accordance with the invention, by way of example and without limitation, provides a wiper arm assembly that is easy to assemble, is economical in manufacture, is prevented from becoming disassembled during unintended relative rotation between the mounting head and wiper arm, and has a long and useful life.

DETAILED DESCRIPTION OF PRESENTLY PREFERRED EMBODIMENTS

Referring in more detail to the drawings,FIGS. 1-6show a wiper arm assembly10constructed according to one presently preferred embodiment of the invention. The wiper arm assembly10has a mounting head12to facilitate attachment of the assembly10to a vehicle, and a wiper arm14for operable attachment of a wiper blade (not shown) to the assembly10. The wiper arm14is attached for articulated movement to the mounting head12via a hinged joint16so that the wiper arm14can be pivoted in use and during assembly to a vehicle between a preassembled or shipping position (FIGS. 1 and 7) and a fully assembled position (not shown), wherein the assembly10is mounted to a vehicle. While in the shipping position, a locking mechanism18acts between the mounting head12and wiper arm14to prevent them from being pivoted from the shipping position back toward a disassembled position (FIGS. 2 and 8). Accordingly, the wiper arm assembly10is prevented from becoming inadvertently disassembled, such as during shipping or while being handled prior to being attached to the vehicle.

As best shown inFIG. 11, the mounting head12extends between opposite ends23,25and has a mounting portion20adjacent the end23and a hinge portion22adjacent the end25. The mounting portion20preferably has an opening24to facilitate attachment of the assembly10to the vehicle via a standard fastener. The hinge portion22is configured to allow the wiper arm14to articulate relative to the mounting head12. The mounting head12has a pair of laterally spaced sidewalls26,27defining a generally open channel28therebetween. An axle30of a predetermined diameter extends between the sidewalls26,27. The axle30preferably defines a generally cylindrical bearing surface31facing the end25and being spaced a predetermined distance from the end25. The mounting head12has a spring attachment feature, represented here, by way of example and without limitations, as a spring pin32, extending between the sidewalls26,27. To further define the attachment feature, a through opening34is preferably formed adjacent the spring pin32. The spring pin32is located generally between the axle30and the mounting portion20. The mounting head12preferably has at least one, and shown here as a pair of stop surfaces36(FIG. 7-11) arranged to limit the degree of pivot of the wiper arm14upwardly from the mounting head, from the fully assembled position while on the vehicle to the service-up position (FIGS. 5 and 10). It should be recognized that the degree of movement between the assembled position and the service-up position can be varied, as desired, by altering the stop surfaces36.

As shown inFIG. 11, the locking mechanism18is defined in part on the mounting head12by at least one, and shown here as a pair of protrusions, referred to hereafter as locking catches38, extending from the ends25of the sidewalls26,27and generally coplanar thereto adjacent bottom surfaces40of the sidewalls26,27. The bottom surfaces40are preferably substantially flat or planar for mounting engagement with a vehicle surface, although they could be formed having any suitable surface contour. The locking catches38have generally flat locking surfaces42provided in part by generally flat recessed surfaces44extending into the ends25of the sidewalls26,27. The locking surfaces42are represented here, by way of example and without limitation, as being substantially perpendicular to the recessed surfaces44and substantially parallel to the bottom surfaces40.

As best shown inFIG. 12, the wiper arm14has an elongate body extending longitudinally between opposite ends46,48, with one end46, for example, being configured for attachment to the wiper blade, and the other end48being configured for pivotal attachment to the mounting head12. To facilitate operable attachment of the wiper arm14to the mounting head12, the wiper arm14has a spring attachment feature, shown here as a spring hook53(FIGS. 6-10), attached to a bottom or underside surface of the wiper arm14, wherein the spring hook53can be formed as a single piece of material with the wiper arm14, such as in a molding process, for example.

The end48of the wiper arm has a pair of sidewalls47,49laterally spaced from one another with a centrally extending spring channel55located between the sidewalls47,49. The sidewalls47,49have outer surfaces arranged for close receipt within the hinge portion22of the mounting head12between its laterally spaced sidewalls26,27. To minimize friction in use, the sidewalls47,49can have protrusions extending outwardly therefrom a predetermined distance, represented here, by way of example and without limitation, as longitudinal ribs51extending generally along a length direction of the sidewalls47,49.

The end48of the wiper arm is shown as having a hub50, preferably formed as a monolithic piece of material with the wiper arm14, although it could be formed as a separate piece and attached thereafter. The hub50has a pocket52extending into the end48of the wiper arm14a predetermined distance along the length of the hub50to a closed seating surface54. The pocket52and opening formed at the end48is preferably sized for close receipt of the axle30, such that the axle30is free to oscillate within the pocket52. The seating surface54can be formed having a generally cylindrical or constant radius, concave contour to conform generally to the convex cylindrical bearing surface31on the axle30. At least one, and preferably a pair of locking features, represented here by protrusions56, for example, extend laterally away or outwardly from the sidewalls47,49, wherein the protrusions56can be attached to or spaced from the sidewalls47,49. The protrusions56have front abutting surfaces, referred to hereafter as front surfaces58facing the end48for abutment with the locking catches38during assembly and lower locking surfaces, referred to hereafter as stop surfaces60, configured for mating, confronting engagement with the locking surfaces42on the mounting head12. The front surfaces58and stop surfaces60are shown here as being generally perpendicular to one another.

To assemble the mounting head12to the wiper arm14, a spring, shown here as a coil spring62, is attached and tensioned between the mounting head12and the wiper arm14. To facilitate attachment of the coil spring62to the respective attachment locations on the mounting head12and wiper arm14, the coil spring62has hooked, generally c-shaped opposite ends64,65, with one end64being attached to the spring pin32of the mounting head12and the other end65being attached to the spring hook53of the wiper arm14. Upon first attaching the coil spring62, the wiper arm assembly10is in its disassembled position (FIGS. 2 and 8) and the axle30, which is located between the locking surface42and the end20, is preferably placed in abutting contact with the end48of the wiper arm14adjacent the pocket52of the hub50. While in the disassembled position, the wiper arm assembly10is able to be readily taken apart, and can generally fall apart if not handled properly.

To proceed in assembly, the mounting head12and wiper arm14are rotated relative to one another, with the mounting head12being moved counter clockwise, as viewed inFIGS. 3 and 9, wherein the mounting head12and wiper arm14are shown in a partially assembled position. In this position, the axle30, which is located between the locking surfaces42and the end23, begins to enter the pocket52, and the coil spring62is increased in length, thus, increasing the tension force in the spring62. The mounting head12and wiper arm14are rotated further in assembly and the axle30is received in the pocket52so that the tension imparted by the coil spring62pulls or biases the axle30toward the seating surface54. The locking catches38first abut the front surfaces58of the protrusions56(FIG. 4), and the axle30remains spaced from the seating surface54and the locking surfaces42,60remain out of engagement with one another. Accordingly, in this position, the assembly can still be freely rotated back toward the disassembled position, if desired. As the mounting head12and wiper arm14are rotated further relative to each other, the locking catches38clear the respective front surfaces58and snap toward the wiper arm14under the tension and bias of the coil spring62(FIG. 1). Accordingly, the tension in the coil spring62decreases, since the length between its ends is decreased, and the assembly is brought into the shipping position. With the wiper arm assembly10now in the shipping position, the recessed surfaces44on the mounting head12can be configured to engage the front surfaces58on the protrusions56, and the locking surfaces42on the mounting head12engage the stop surfaces60on the protrusions56. Accordingly, the mounting head12and the wiper arm14are prevented from being rotated back toward the disassembled position by the respective locking and stop surfaces42,60. Therefore, once in the shipping position, the wiper arm assembly10is generally locked against disassembly without the aid of tools. When the wiper arm14is assembled in the shipping position, the bearing surface31of the axle30can be configured to seat against the seating surface54while the locking mechanism18is engaged, though it is possible that a slight gap could be present.

As shown inFIG. 5, when the wiper arm assembly10is assembled to the vehicle, the wiper arm14can be rotated further in a counter clockwise direction (the same direction of rotation used to assembly the mounting head12to the wiper arm14) relative to the mount head12into the service-up position. During rotation toward the service-up position, the axle30preferably remains seated against the seating surface54. While in the service-up position, the wiper arm14, and thus, the wiper blade are moved away from the vehicle window.

Obviously, many modifications and variations of the present invention are possible in light of the above teachings. For example, as shown inFIG. 14, it should be recognized that the axle30and the hub50could be constructed in the reverse orientation. Accordingly, an axle130could be attached to a wiper arm114, and a hub150could be formed or attached on a mount head112. Similarly, as shown inFIG. 15, the structure of the locking mechanism18could be reversed. Accordingly, a locking catch238could be attached on a wiper arm214, and protrusions256and associated stop surfaces260could be attached to a mount head212. It is, therefore, to be understood that within the scope of the appended claims, and any other claims allowed which stem from this application, that the invention may be practiced otherwise than as specifically described and shown.