Seat bolster adjustment apparatus and method

[0001] None.

[0002] None.

[0003] This invention relates generally to an apparatus for reducing muscle fatigue and discomfort of a seated occupant and, more particularly, to adjustable bolsters for seats, especially automobile seats.

[0004] Vehicle seats commonly utilize bolsters on the sides of the seat back to assist the occupant in remaining centered within the seat. Bolsters are typically positioned vertically to engage the torso of the occupant near the bottom of the occupant's rib cage. Bolsters help maintain the occupant in a fixed position during vehicle maneuvers that might otherwise displace the occupant in a lateral direction.

[0005] Because occupants vary greatly in size, variable position bolsters have been developed. These variable bolsters allow the occupant to adjust the area between a seat's bolsters to better suit the occupant's build while maintaining the desired level of lateral movement control of the occupant. U.S. Pat. No. 5,857,743 illustrates one example of a variable bolster system.

[0006] Existing bolster systems generally utilize Bowden type traction cable assemblies as part of a means for adjusting the bolster positions. Bowden cables are coaxial mechanical devices wherein a wire slides axially through a sleeve or conduit. While Bowden cable systems can be an efficient means for applying traction to moving parts in ergonomic devices, they require relative large amounts of space. The Bowden cable mechanisms utilized in these existing systems result in slower response time of the bolster adjustment mechanism to a control signal, making these existing systems unsuitable for dynamically adjustable bolster systems. Furthermore, Bowden cable assemblies are not modular and usually must be replaced as an entire unit. In addition, existing bolster systems require distinct right and left bolster assemblies that are not interchangeable. These factors increase the costs of manufacture, storage and assembly associated with existing bolster adjustment mechanisms.

[0007] The present invention is directed to overcoming one or more of the problems set forth above.

[0008] An aspect of the present invention is to provide an adjustable bolster system having a more compact and modular package design and a faster adjustment response.

[0009] Another aspect of the present invention is to provide a dynamically adjustable bolster system with a largely self-contained design and a variable mounting capability.

[0010] Another aspect of the present invention is to provide an adjustable bolster system capable of independent adjustment of each individual bolster.

[0011] Yet another aspect of the present invention is to provide a bolster system that is compatible with a dynamic bolster adjustment system, which is capable of adapting to variable lateral forces exerted on a vehicle occupant during changing travel conditions.

[0012] In accordance with the above aspects of the invention, there is provided an active bolster adjustment apparatus for use in seats that includes a mounting plate connected with the seat frame, an adjustable bolster slider in sliding communication with the mounting plate, and a drive unit in communication with the adjustable bolster slider, the drive unit having an actuator and a gear set. Although the invention would be appropriately used in a vehicle seat, such use should not be deemed limiting in any manner, and the invention may be used for any type of seat in which an adjustable bolster system is desired.

[0013] These aspects are merely illustrative of the innumerable aspects associated with the present invention and should not be deemed as limiting in any manner. These and other aspects, features and advantages of the present invention will become apparent from the following detailed description when taken in conjunction with the referenced drawings.

[0020] In the following detailed description numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. For example, the invention is not limited in scope to the particular type of industry application depicted in the figures. In other instances, well-known methods, procedures, and components have not been described in detail so as not to obscure the present invention.

[0021] An active bolster system for a vehicle seat is illustrated in FIGS. 1–4. The active bolster system 10 is associated with a seat bolster. A seat bolster may have a separate unit 14 as depicted in FIG. 4 or an integral pressure surface 36 on an adjustable bolster slider 20 as depicted in FIGS. 1–3. A bolster adjusting mechanism 16 varies the position of the seat bolster 14, thereby changing the lateral support provided to an occupant of the seat. The bolster adjusting mechanism 16 includes a mounting plate 18, an adjustable bolster slider 20, and a drive unit 22. In this embodiment, the seat bolster 14 is interposed between the seat occupant and the bolster adjustment mechanism 16. In an alternate embodiment, the bolster adjustment mechanism 16, and, in particular, the pressure surface 36 (described below), acts directly on the occupant with no interposing bolster cushion. The active bolster system described herein is suitable for operation in either of these embodiments.

[0022] The mounting plate 18 is fixed to a seat frame 12. The mounting plate 18 is provided with a guide section 24 and a frame mounting section 26. In the embodiments shown in FIGS. 1–4, the frame mounting section 26 is provided with plural mounting holes 28 through which bolts, rivets, screws or other similar devices are inserted in order to secure the mounting plate 18 to the seat frame 12. Other mounting means, for example welding or adhesive, may also be utilized to secure the mounting plate. The guide section 24 serves the dual purpose of guiding the movement of the adjustable bolster slider 20, as will be explained in detail below, and providing a mounting surface for the drive unit 22. The guide section 24 is formed by a pair of parallel walls 30, 32 that rise perpendicularly from the frame mounting section 26 and a top surface 34 which extends between the walls 30, 32 parallel to the frame mounting section 26. In the embodiment shown, the top surface 34 is provided with an access hole (not shown) that allows the drive unit 22 to communicate with the adjustable bolster slider 20. The access hole may be of any suitable shape and size to accommodate the gearing associated with the drive unit 22.

[0023] The adjustable bolster slider 20 includes a pressure surface 36 and an adjustment arm 38 wherein the pressure surface 36 is situated at a distal end of the adjustment arm 38 as shown in FIGS. 1–4. The seat bolster 14 is connected to the pressure surface 36. The adjustment arm 38 is provided with a narrower, more elongated configuration than the pressure surface and is designed to interact with the guide section 24 of the mounting plate 18. During assembly of the adjustment mechanism, the adjustment arm 38, with width w, is inserted into the space defined by the walls 30, 32, the frame mounting section 26 and the top surface 34 of the mounting plate 18. During operation of the mechanism, this space partly defines the path that the adjustment arm 38, of the slider 20, travels through. The adjustment arm 38 includes a strip of gear teeth 40, which engage gear teeth (not shown) in the drive unit 22. In the depicted embodiment, the adjustment arm 38 has an angular or arcuate shape.

[0024] The drive unit 22 includes an actuator 42 and a gear set 44. In the embodiment shown the actuator 42 is an electric motor. In a preferred arrangement, the actuator 42 is directly connected to the gear set 44. The gear set 44 in the drive unit 22 meshes with the strip of gear teeth 40 on the adjustment arm 38. The gear set includes a series of gears (not shown) arranged to transfer the motive force of the actuator 42 to the adjustment arm 38.

[0025] Gear sets of this type are well-known in the art, and, therefore, the following embodiments are not shown in detail in the accompanying drawings. In one embodiment, the actuator 42 includes an output shaft extending from the actuator towards the gear set 44. A first bevel gear is affixed to the end of the output shaft and is turned with the output shaft by the actuator. A second bevel gear is oriented at a ninety degree angle to and engages with the first bevel gear. The second bevel gear is rotatably mounted on a post that is secured to the housing of the gear set 44. The second bevel gear extends downward from the gear set 44 to engage the gear teeth 40 of the adjustment arm 38. The second bevel gear may be comprised of two separate but connected gears, one engaging with the first bevel gear and the second engaging the gear teeth 40 of the adjustment arm. In alternate embodiments, gear sets utilizing three or more gears are provided to transfer the rotation of the actuator 42 to the adjustment arm 38. The gear ratios of these alternate gear sets may be varied to control the movement of the adjustment arm 38. Alternate gearing arrangements are well-known in the art and may be substituted for the described embodiments.

[0026] The drive unit 22 is also provided with a mounting surface (not shown) to allow the drive unit 22 to be fixed to the top surface 34 of the guide section 24. The mounting surface of the drive unit 22 and the top surface 34 of the mounting plate 18 are provided with a means for pivotably mounting the drive unit 22 to the top surface of the mounting plate 18. The means for pivotably mounting the drive unit 22 allow the actuator to be rotated relative to the mounting plate 18, thereby providing a variety of mounting positions for the bolster adjustment mechanism relative to the seat frame and increasing the flexibility of the active bolster system. In one embodiment, the means for pivotally mounting the drive unit 22 is formed by a plurality of mounting holes (not shown) located in the top surface 34 of the mounting plate 18. In another embodiment, the means for pivotally mounting the drive unit 22 includes a mounting pin (not shown) that is rotatably connected with the drive unit 22 and the top surface 34 of the mounting plate 18. The mounting pin is preferably connected with a generally central point of the gear set 44 of the drive unit and a generally central point of the top surface 34 of the mounting plate 18. Other suitable pivoting mounting arrangements are well-known in the art and, therefore, are not described in detail here.

[0027] The direct drive system described above eliminates the use of Bowden cables to control the seat bolsters and results in a more compact bolster adjustment package. In addition, this arrangement provides a modular design that enables the left and right bolster adjustment mechanisms to be removed and replaced independently of one another. Furthermore, the adjustable mounting feature of the drive unit allows a single design to serve both the right and left sides of the seat. Active bolster system 10 is designed for mounting to lateral portions of seat frame 12 (FIG. 5), to provide lateral support to a seat occupant. Curved, double-headed arrows suggest the direction of arcuate movement of pressure surface 36, as depicted in FIG. 4.

[0028] As the actuator 42 rotates, it drives the gear set 44. The gear set 44, in turn, drives the strip of gear teeth 40, and with it the slider 20, in a lateral direction. The amount and direction of rotation of the actuator 42 and gear set 44 determines the amount and direction of travel of the slider 20. In the preferred embodiment with an angular-shaped adjustment arm 38, the resulting motion of the pressure surface 36 is an arc.

[0029] The active bolster system is particularly well-suited for operation with a dynamic bolster adjustment system. In such a system, the active bolster system operates in conjunction with a control unit and multiple vehicle performance sensors. The control unit may be a microcomputer, a programmable controller, or any other suitable programmable unit known in the art. The control unit communicates with and controls the drive units of the left and right bolster assemblies independently. In a one embodiment, the vehicle performance sensors include an acceleration sensor, a velocity sensor, and a steering angle sensor. Each of these sensors continuously communicates a signal that reflects the current acceleration, velocity or steering angle to the control unit during vehicle operation. From these signals, the control unit calculates the approximate current lateral forces being exerted on the vehicle occupants. Based on the amount and direction of the current lateral forces being exerted, the control unit determines the proper positioning for each of the left and right bolsters. The control unit then signals the amount and direction of rotation of each actuator required to achieve those positions. The control unit then transmits separate signals to the drive units of the left and right bolster assemblies directing the actuator of the each drive unit to rotate the desired amount in the proper direction. This results in the left and right seat bolsters being properly positioned to provide optimal lateral support for the seat occupant based on the current lateral forces being exerted on the occupant.

[0030] Other objects, features and advantages of the present invention will be apparent to those skilled in the art. While preferred embodiments of the present invention have been illustrated and described, this has been by way of illustration and the invention should not be limited.