PLASTIC CARRIER APPARATUS FOR MOTOR VEHICLE WIPER

SYSTEMS

Related Technical Field The present invention relates to a carrier apparatus used for fixing the wiper systems to the motor vehicles.

State of the Art

The windshield wiper systems used in the motor vehicles preferably comprise two wipers, one for the driver and the other for the passenger, a wiper motor that provides the forward-backward movement of the said wipers on the windshield, two shafts, each for transmitting the movement provided by the motor to a wiper, a transmission mechanism composed of articulated rods, and a carrier apparatus that is used for fixing the said components to the vehicle frame.

The carrier apparatus generally comprises a main carrier pipe, shaft bearings at both ends of the said main carrier, wherein the shafts connected to the wiper arm are fitted, and a motor bracket that is used for fixing the wiper motor. The carrier apparatus, an example of which is given in the patent document no. DE7434119, has a straight pipe with a rectangular cross-section as the main carrier. The shaft bearings are fixed to both ends of the said pipe by press fitting. The motor bracket is fixed to the said pipe by welding. In this arrangement, producing the components of the apparatus separately increases mold costs. Moreover, that each of the metal components has a different production tolerance makes the assembly of the carrier apparatus very laborious and costly. Additionally, it may become necessary to bend the straight main carrier pipe so as to be placed into the engine compartment. This additional process will increase the production time and production costs. In the patent document no. EP0798183, a carrier apparatus wherein the main carrier pipe and the shaft bearings are produced as a single piece is disclosed. A metal pipe to be used as the main carrier is bent and then placed into a mold. With the pressure provided by the fluid pumped into the pipe the walls of the pipe are pushed into the cavities formed in the mold. By means of this process, solid cylindrical members are produced. By applying operations such as cutting, drilling, etc. to the cylindrical members, hollow housings for receiving the shaft bearings and the motor are formed. Although the apparatus is more easily produced by means of this embodiment, additional processes such as cutting, drilling, bending, etc. are required. These additional processes increase the production time and production costs. Moreover, the motor bracket required for safely fixing the motor cannot be produced by this method. Furthermore, the apparatus that is produced from metal material is heavy and costly.

The patent no GB2219932 discloses a carrier apparatus produced by plastic injection molding. The apparatus is a single piece composed of a bracket to which the motor is connected, carrier arms extending from the said bracket towards both sides and shaft bearings provided at the end of the said arms. The carrier arms have a honeycomb- shaped structure composed of two side walls and support traverses provided between the walls. This design is cheaper and more easily producible with respect to the above- described metal carrier apparatus. However, due to the support traverses provided between the carrier arm walls, sufficient advantage in terms of weight cannot be obtained.

By means of the present invention, a plastic carrier apparatus that is produced as a single piece in a single process and that comprises a hollow main carrier pipe, shaft bearings provided at both ends of the said main carrier, at least one connection member for fixing the said main carrier to the vehicle frame and a motor bracket used for fixing the wiper motor is disclosed.

The present invention is explicated below in detail with reference to the figures.

Figure la is the isometric view of the carrier apparatus of the present invention. Figure lb is the detailed view of the motor bracket of the carrier apparatus of the present invention.

Figure 2 is the isometric view of the mold used for producing the carrier apparatus of the present invention. Figure 3 is the simplified view of one half of the mold used for producing the carrier apparatus of the present invention.

Figure 4 is the view of the horizontal core set used for producing the carrier apparatus of the present invention.

Figure 5 is the view of the vertical core set used for producing the carrier apparatus of the present invention.

The elements related to the present invention are numbered as follows in the above- described figures:

Carrier Apparatus 1

Main Carrier Pipe 2

Middle Portion 20

Arm 21,22

Bend 23

Shaft Bearings 3

Motor Bracket 4

Upper wall 41

Side wall 42

Front wall 43

Hole 44

Housing 45

Support Traverse 46

Connection Members 5

Mold 6

Mold Half 7,7'

Mold Cavity 70 Horizontal Core Set 8

Male Core Half 81

Cylindrical

Protrusion 810

Female Core Half 82

Hole 820

Cavity 83

Vertical Core Set 9

Male Core Half 91

Protrusion 910

Female Core Half 92

Cavity 93

Groove 94

Detailed Description of the Invention

The carrier apparatus (1), the isometric view of which is shown in Figure la, is a plastic single piece comprising a hollow main carrier pipe (2), at least one shaft bearing (3), a motor bracket (4) and at least one connection member (5).

The main carrier pipe (2) is composed of a middle portion (20) and two arms (21, 22) extending towards both sides from the said portion (20). The pipe (2) has preferably circular cross-section. The pipe (2) has at least one bend (23) preferably at the regions where the arms (21, 22) and the middle portion (20) join. The middle portion (20) of the carrier pipe (2) is generally positioned at a level lower than the two arms (21 , 22). While the middle portion (20) is integrated with the motor bracket (4) used for fixing the wiper motor, the arms (21, 22) are integrated with the connection members (5) to be connected to the vehicle frame.

The shaft bearing (3) is provided at the end of the arms (21, 22) of the main carrier pipe (2), perpendicular to the longitudinal axis of the pipe (2). The shaft bearing (3) is in the form of a hollow vertical cylinder for bearing the shafts connected to the wiper arms. The carrier apparatus (1) preferably comprises the connection members (5) joined with the shaft bearings (3). The connection member (5) houses components such as screw, rivet, bolt, etc. used for fixing the carrier apparatus (1) to the vehicle frame. The connection member (5) preferably has an open-ended U section structure. However, according to the arrangement, hollow connection members (5) that have different cross- sections such as circular, rectangular, etc. can be provided on the apparatus (1). Moreover, according to the arrangement, the connection members (5) can be positioned at different points of the carrier apparatus (1).

The motor bracket (4) shown in detail in Figure lb is provided as integrated with the middle portion (20) of the main carrier pipe (2), perpendicular to the longitudinal axis of the pipe (2). The bracket (4) is generally a plate having upper (41), side (42) and front (43) walls. Connection holes (44) are provided on the bracket (4). By means of the said connection holes (44), the motor connected to the underside of the bracket (4) is enabled to be fixed to the bracket (4) by means of components such as bolt, etc. or by means of welding. Although the connection holes (44) are provided on the upper wall (41), the said holes (44) can be formed on the front wall (43) or the side wall (42). In addition to the connection holes (44), a circular section housing (45) is provided on the upper wall (41) of the bracket (4). The drive shaft transmitting the movement provided by the motor to the shafts by means of transmission mechanisms is fitted into the said housing (45). If required, in order to obtain a strong apparatus (1), at least one support traverse (46) can be provided between the upper wall (41) of the bracket (4) and the main carrier pipe (2).

The carrier apparatus (1) of the present invention is produced as a single piece in a single process by liquid injection technologies, preferably by water injection technology. Figure 2 shows the isometric view of the mold (6) used in this production method. The mold (6) composed of two halves (7, 7') closed over one another has a mold cavity (70) wherein the plastic material is injected. In Figure 3, the simplified view of one of the said two halves (7) from above is given in order to make the mold cavity (70) more apparent. In the other mold half (7') not shown in the figure, a complementary cavity for the mold cavity (70) is provided. The mold cavity (70) has the same routing as the main carrier pipe (2) to be produced. The mold (6) comprises horizontal core sets (8) for forming the shaft bearings (3) and the connection members (5) at the end portions of the mold cavity (70). The horizontal core sets (8) are provided parallel to the mold cavity (70). The vertical core set (9) provided preferably at the center of the mold cavity (70) is used for forming the motor bracket (4). The vertical core set (9) extends perpendicular to the mold cavity (7) and into the mold half (7).

As seen in Figure 4, the horizontal core set (8) composed of two halves, namely the female (82) and the male (81) comprises a core cavity (83). The said cavity (83) having the same geometric form as the shaft bearing (3) and the connection member (5) provides the molding of the contour of the shaft bearing (3) and the connection member (5). Moreover, in order to form the shaft bearing (3) as a hollow component, a cylindrical protrusion (810) is provided in the male half (81) of the horizontal core set (8) and a hole (820) bearing the said protrusion (810) is provided in the female core half (82).

Figure 4 shows the vertical core set (9) composed of one male half (91) and one female half (92). The vertical core set (9) comprises a core cavity (93) having the same geometric form as the motor bracket (4). Protrusions (910) are provided on the male core half (91). The said protrusions (910) generally have a circular cross-section and provide the formation of the connection holes (44) and the housing (45) on the bracket (4). Moreover, a groove or grooves (94) are formed on at least one of the core halves (91 , 92) for obtaining the support traverse (46).

In the first step of the method, the plastic molten material injected through a nozzle in the mold fills in the mold and core cavities (70, 83, 93). When the molten material filling into the core cavities (83, 93) solidifies, the shaft bearings (3), the connection members (5) and the motor bracket (4) are formed. In the second step of the method, pressurized liquid is pumped into the mold cavity (70). The pressurized liquid expels the hot and liquid material at the center of the plastic molten material filling the mold cavity (70) from the mold cavity (70). Thus, the plastic carrier apparatus (1) is obtained by forming the hollow main carrier pipe (2). Although the pressurized liquid used for emptying the inner region of the plastic molten material in the method is preferably water, pressurized gas can be also used in different embodiments. Moreover, alternatively, the inner region of the plastic molten material can be also emptied by mean of a projectile.

In an alternative arrangement, the number of the connection members (5) provided on the carrier apparatus (1) can be increased or decreased. By providing additional brackets on the carrier pipe (2), the strength of the carrier apparatus (1) can be improved. In a different embodiment, a bellows form can be provided on the main carrier pipe (2) in order to absorb the vibrations that the apparatus (1) may be subjected to on the vehicle. The cross-section of the main carrier pipe (2) can be in different forms such as quadrangular, elliptic, etc. apart from circular. According to the embodiment, the main carrier pipe (2) can have a sectionally-varying cross-section.

The carrier apparatus (1) can be produced from a thermoplastic material such as polyphthalamide (PPA), polyamide (PA), polypropylene (PP), polyphenylene sulphide (PPS), polyethylene (PE), polybutylene terephthalate (PBT), thermoplastic elastomer (TPE), etc. The apparatus (1) can be produced in multiple layers by using plastic materials with different characteristics. Moreover, if required, the inner region of the main carrier pipe (2) can be filled with a plastic material so as to render the same stronger.