Patent Application
20050284689
The present invention generally relates to a clockspring for a vehicle steering wheel that includes a sound dampener. More specifically, the sound dampener significantly reduces noise created both by friction between the clockspring and its flat cable and by vibration of the clockspring.
Clocksprings are typically provided in a vehicle steering wheel to supply electrical power via a flat cable to certain components, such as an air bag. Conventional clocksprings produce noise typically caused by the movement and vibration of the flat cable within the clockspring housing. In particular, as the flat cable winds and unwinds within the clockspring housing, friction between the flat cable and the housing wall surfaces creates noise. Additionally, vibration of the clockspring, particularly when the vehicle is idling, creates additional noise due to movement of the flat cable and collisions with the clockspring housing walls.
Some conventional clocksprings employ a noise absorbing structure which often fail to effectively absorb noise and/or fail to absorb the noise caused by both friction between the flat cable and the clockspring housing and vibration of the clockspring.
Examples of conventional clocksprings with sound absorbing structure includes U.S. Pat. No. 6,457,549 to Sugata; U.S. Pat. No. 6,196,488 to Sakata et al.; and U.S. Pat. No. 6,019,621 to Sugata et al., the subject matter of each of which is herein incorporated by reference.
Accordingly, an object of the present invention is to provide a clockspring with a sound dampener that effectively absorbs noise caused by both friction between the flat cable and clockspring housing and vibration of the clockspring.
The foregoing object is attained in accordance with the present invention by a sound dampener including a first layer that has first and second opposite surfaces. The first layer is substantially ring-shaped with a first central aperture with a first perimeter. A second layer is disposed on one of the first and second opposite surfaces of the first layer. The second layer is substantially ring-shaped with a second central aperture with a second perimeter. The second perimeter defines a circumference that is smaller than a circumference of the first perimeter of the first central aperture so that an extended portion of the second layer extends beyond the first perimeter of the first central aperture of the first layer.
The foregoing objects are also attained in accordance with the invention by a clockspring including a stationary member that has a first bearing surface and a movable member rotatably engaged with the stationary member. The movable member has a second bearing surface. A cable retaining compartment is defined between the stationary and movable members. A flat cable is disposed in the cable retaining compartment, and having opposite first and second ends and opposite first and second side edges. A sound dampener is disposed between either one of the first bearing surface of the stationary member and the first side edge of the flat cable and the second bearing surface of the movable member and the second side edge of the flat cable so that there is substantially no space between the first bearing surface and the first side edge and between the second bearing surface and the second side edge. The sound dampener has a first foam layer with a second smooth layer disposed on the first foam layer.
The foregoing objects are also attained in accordance with the invention by a clockspring including a stationary member having a first bearing surface and a movable member rotatably engaged with the stationary member. The movable member has a second bearing surface. A cable retaining compartment is defined between the stationary and movable members. A flat cable is disposed in the cable retaining compartment, and has opposite first and second ends and opposite first and second side edges. A sound dampener is disposed between either of the first bearing surface of the stationary member and the first side edge of the flat cable and the second bearing surface of the movable member and the second side edge of the flat cable, and the sound dampener has a first layer with a first central aperture defining a perimeter with a second layer disposed on the first layer and including an extended portion extending beyond the perimeter of the first layer.
Other objects, advantages and salient features of the invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses preferred embodiments of the present invention
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
Referring to
Sound dampener 20 reduces noises caused by the frictional engagement of the flat cable 18 with either the stationary or moveable members 14 and 16 and the impact of the flat cable 18 with either member 14 and 16 during vibration of the clockspring 10, such as when the vehicle is idling. Sound dampener 20 substantially eliminates all space between the flat cable 18 and members 14 and 16 via a first thick layer 24 to substantially reduce vibrational noises and provides a smooth continuous surface via a second layer 26 to substantially prevent frictional noises. Additionally, an extended or overhang portion 28 can be included with the sound dampener 20 to provide a continuous smooth surface for engaging the flat cable 18.
As seen in
A circular disk 44 is disposed within wall 30 at the edge 38 opposite free edge 40 and attached to wall 30 by any known attachment method. Circular disk 44 includes a central aperture 46 defining a central perimeter 48. Circular disk 44 includes inner bearing surface 50. As seen in
As seen in
A circular disk 60 extends from outer surface 56 of wall 52. A free edge 62 of wall 52 abuts circular disk 44 of stationary member 14 and is aligned with central aperture 46 thereof. Circular disk 60 includes an inner bearing surface 64 and an opposite outer surface 66. Like bearing surface 50 of stationary member 14, bearing surface 64 forms a portion of cable cavity 22. Circular disk 60 also includes a ledge 68 surrounding cylindrical wall 52 along the periphery of moveable member 16 that has a transition shoulder 70. An outer secondary wall 72 extends around the outer perimeter of circular disk 60. As seen in
Flat cable 18 includes opposite first and second ends 76 and 78. First end 76 of flat cable 18 is connected to connector unit 42 of stationary member 14. Second end 78 is connected to connector unit 74 of moveable member 16. As seen in
As seen in
As seen in
First layer 24 is substantially thicker than second layer 26. First layer 24 is preferably formed of a resilient material, such as foam, including open cell and closed cell foam, microporous plastic, polystyrene, and the like, to fill the space or gaps between the sides edges 80 and 82 of flat cable 18 and the bearing surfaces 50 and 64 of stationary and moveable members 14 and 16, respectively and provide a cushioning effect. Second layer 26 is preferably formed of a smooth or slidable material, such as polyethylene, thermoplastic resin, polyester, and the like, thereby defining a smooth engagement surface 100 for engaging the side edges 80 and 82 of flat cable 18.
An adhesive layer 102 can be applied to first layer 24 opposite second layer 26, as seen in
When clockspring 10 is assembled, wall 52 of moveable member 16 is disposed within wall 30 of stationary member 14. Flat cable 18 is received in cable cavity 22 defined between walls 30 and 52 and bearing surfaces 50 and 64 of stationary and moveable members 14 and 16, respectively. Free edge 40 of stationary wall 30 is disposed near circular disk 60 of moveable member 16. Free edge 62 of moveable wall 52 abuts circular disk 44 of stationary member 14 with inner passageway 54 of moveable member 16 and central aperture 46 of circular disk 44 being aligned. Clip 84 extends through central aperture 46 of wall 30 and into inner passageway 54 of wall 52 to couple stationary and moveable members 14 and 16. In operation, flat cable 18 winds and unwinds within cable cavity 22 as the steering wheel is turned.
Sound dampener 20 is disposed within cable cavity 22 and can be applied to bearing surface 64 of moveable member 16, as seen in
The thick first layer 24 of sound dampener 20 fills any gaps between the flat cable side edges 80 and 82 and the bearing surfaces 50 and 64 of stationary and moveable members 14 and 16, respectively, thereby leaving substantially no space between bearing surfaces 50 and 64 and flat cable 18, as seen in
Sound dampener 20 adjusts to variability in sizes of the components of clockspring 10, such as the stationary and moveable members 14 and 16. Size variability often occurs due to the molding of the components. In particular, since the first layer 24 of sound dampener 20 is made of a resilient material, such as foam, sound dampener 20 can be compressed to accommodate the variability in sizes of the molded components. There is a very slight interference fit between the edges of flat cable 18 and dampener 20 leaving no space therebetween but allowing flat cable 18 to move as it winds and unwinds within the clockspring.
The second layer 26 of the sound dampener 20 reduces the friction between flat cable side edges 80 and 82 rubbing against bearing surfaces 50 and 64 as flat cable 18 is wound and unwound within cable cavity 22 by providing smooth engagement surface 100, thereby significantly reducing the frictional noise. Extended portion 28 ensures that smooth engagement surface 100 extends to wall 52 of moveable member 16. Otherwise, side edges 80 and 82 of flat cable 18 may rub against exposed areas of bearing surfaces 50 and 64, such as ledge 68 of bearing surface 64 creating unwanted frictional noise. The combination of the first and second layers 24 and 26 of sound dampener 20 significantly reduce both vibrational noise and frictional noise.
Referring to
Sound dampener 220 is used with clockspring 10 in the same manner as sound dampener 20. Cutout section 287 can be aligned with either connector unit 42 and 74 of stationary and moveable members 14 and 16, respectively, to accommodate flat cable 18 at the connection area of either connector unit 42 and 74.
Referring to
Sound dampener 320 is used with clockspring 10 in the same manner as sound dampener 20. Fingers 329 extend smooth engagement surface 100 to along outer surface 58 of wall 52 of moveable member 14.
Referring to
Sound dampener 420 is used in generally the same manner as sound dampener 20 of the first embodiment. Flexible area 430 can move in and out of pocket 432 to adjust to the flat cable 18 and the variability of the component sizes. The flat cable 18 and engagement surface 100 of dampener 420 engage with a slight interference fit.
Referring to
While particular embodiments have been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modification can be made therein without departing from the scope of the invention as defined in the appended claims.
