Abstract:
A dual drive actuation system includes a driver gear, a pair of actuators with driven gears, and a transmission for switching the driver gear between the pair of actuators. The transmission is controlled by a solenoid, and the driver gear is powered by a motor. The dual drive actuation system can be used with different actuators that are changed based on their required usage, sizing and range of motion.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a divisional application of application Ser. No. 10/770,940, filed Feb. 3, 2004, now U.S. Pat. No. 6,983,990. 

   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   Not Applicable. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates generally to actuators for ergonomic systems and, more particularly, to actuator systems for seat adjustments. 
   2. Related Art 
   Ergonomic supports for seats, such as lumbar and bolster systems, are typically moved by means of actuators that can be operated by hand or driven by a motor. Four-way power lumbar devices, with an arching mode and a translation mode, have traditionally required a motor for each mode of operation. In comparison, the invention set forth by U.S. Pat. No. 6,050,641 is a four-way power lumbar system that requires only a single-motor and reduces the duplication of gearbox components. Prior to this invention, U.S. Pat. Nos. 5,197,780 and 5,217,278 had only described four-way lumbar devices that were manually operated by a single control knob. 
   While these devices are an improvement over the conventional four-way lumbar devices that required multiple motors or multiple control knobs, the highly competitive markets for furniture and automotive seats place a premium on continued optimization of devices that provide comfort and convenience for seat occupants. In particular, there is a need for improved actuation systems that are less prone to failures and more efficiently transfer power to the actuators. For example, with regard to the manually-operated four-way lumbar systems, the gearing systems are inefficient because, in addition to the gears, they have a transmission that requires at least one non-gear alignment device to maintain the proper engagement between the driver gear and the driven gears. Therefore, such devices have an alignment device that is necessary for the convenient operation of the lumbar system and increase the potential for a failure in the system. 
   Additionally, there is a need for actuation systems that are more modular, increasing the commonality of parts between two-way and four-way power lumbar devices, manually-operated and motor-driven actuation systems, and lumbar systems and bolster systems. For example, the prior art actuation units and driven gears are designed to fit within a single housing along with the driver gears and the transmission system, thereby limiting the range of motion that is capable for the actuation units themselves. Different types of lumbar devices and bolster devices are typically designed to provide different levels of support and often require different levels of actuation, thereby affecting the size of the actuators. The prior art devices do not easily allow for changing the actuators according to various sizing requirements, and the confined housing could prevent the same actuation system from being used for different lumbar devices or for a lumbar device and a bolster device. Therefore, entirely different actuation systems would need to be designed, and separately manufactured, depending on the actuators&#39; usage, range of motion, and sizing. 
   SUMMARY OF THE INVENTION 
   It is in view of the above problems that the present invention was developed. The invention is a dual drive actuation system that can combine existing two-way manual actuators with a gearing system to switch between multiple actuators. Additionally, the dual drive actuation system can be powered by a motor, and a solenoid can be used to switch the gearing system between the actuators. The dual drive actuation system can be used with different actuators that are changed based on their required usage, sizing and range of motion. 
   Further features and advantages of the present invention, as well as the structure and operation of various embodiments of the present invention, are described in detail below with reference to the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are incorporated in and form a part of the specification, illustrate the embodiments of the present invention and together with the description, serve to explain the principles of the invention. In the drawings: 
       FIG. 1  illustrates the dual drive actuation system of the present invention; 
       FIG. 2  illustrates the dual drive actuation system installed in a seat with a lumbar device; 
       FIG. 3  illustrates the dual drive actuation system installed in a seat with a bolster device and a headrest device; 
       FIG. 4  illustrates the dual drive actuation system according to another embodiment of the present invention; 
       FIG. 5  illustrates the dual drive actuation system of the present invention depicting the gear arrangement and gear teeth positioning; 
       FIG. 6  illustrates the dual drive actuation system installed in a seat with the bolster device, headrest device, and a pair of dual drive actuation devices; 
       FIG. 7  illustrates the dual drive actuation system installed in a seat with the bolster device, headrest device, and a pair of dual drive actuation devices having worm driver gear arrangements; and 
       FIG. 8  illustrates the dual drive actuation system installed in a seat with a lumbar device, with the dual drive actuation device positioned in a seat back. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to the accompanying drawings in which like reference numbers indicate like elements,  FIG. 1  illustrates an embodiment of the dual drive actuation system  10 . In this embodiment, the dual drive  10  includes a pair of actuators  12 ,  14  that have a respective pair of actuated bevel gears  16 ,  18  and a drive shaft  20  that has a pair of driver bevel gears  22 ,  24 . The position  26  of the drive shaft  20  is shifted to alternatively engage the actuated bevel gears  16 ,  18  with the driver bevel gears  22 ,  24 . The driver bevel gears  22 ,  24  can be a double-sided bevel gear  28 , as exemplified in  FIG. 1 , with the gear teeth facing away from each other in opposite directions. 
     FIG. 5  illustrates the gear arrangement and gear teeth positioning. When the drive shaft  20  shifts towards an actuator  12 , one side of the double-sided bevel gear  22  respectively engages with its corresponding actuated bevel gear  16  while the other side  24  disengages from its corresponding actuated bevel gear  18 , and vice versa. The engagement of bevel gears between the actuators  12 ,  14  and the drive shaft  20  simplifies the gearing system because the bevel gears have opposing surfaces on the driver side and driven side. These opposing surfaces also serve as a mechanical stop to constrain the drive shaft  20  to whichever actuated bevel gear is engaged, eliminating any need for a biasing spring, retaining device, or any other stop mechanism in addition to the bevel gears themselves. 
   As also exemplified in  FIGS. 1 and 5 , a solenoid  30  or any other type of control unit or its equivalent can be used to control the position  26  of the drive shaft  20 , and a motor  32  or any other type of power unit or its equivalent can be used to power the drive shaft  20 . By changing the position  26  of the drive shaft  20 , the solenoid  30  selectively moves the double-sided bevel gear  28  between the actuators  12 ,  14 . The motor  32  powers a rotating shaft  34  that engages the drive shaft  20  through a set of gears, such as a pinion  36  attached to the motor&#39;s shaft  34  which meshes with a spur  38  attached to the drive shaft  20 . 
   The actuators  12 ,  14  can manipulate the adjustment devices ( FIGS. 2 ,  3 , &amp;  8 ) with a respective pair of bowden cables  40 ,  42 . The dual drive actuation system  10  is modular because the actuators  12 ,  14  can be switched depending on the adjustment device being manipulated. For example, different types of lumbar supports are typically designed to provide different levels of support and often require different levels of actuation. Additionally, in any given four-way lumbar, it is likely that the arching mechanism requires a different level of actuation than the translation mechanism. Similarly, different types of bolster devices may also require different levels of actuation, and the level of actuation designed for a bolster device in a seat is likely to be different from the level of actuation for a lumbar device in the same seat. Even though these different adjustment devices can each have a different actuation requirement, the actuators  12 ,  14  can all be a part of the same family with actuated bevel gears  16 ,  18  that mesh with the driver bevel gears  22 ,  24 . Accordingly, the actuators  12 ,  14  can be selected from this group of modular actuators that have different maximum levels of actuation but have the same actuated bevel gears  16 ,  18 . The same actuators used for a manually-operated dual drive actuation system can also be used for a motor-driven dual drive actuation system, further increasing the commonality of parts and thereby reducing the cost of the systems. 
   Among the different types of actuators that can be used to manipulate seat adjustment devices are those that operate with bowden cables, such as those described in U.S. Pat. Nos. 5,638,722 and 6,053,064 and in pending U.S. application Ser. No. 10/008,896. A family of bowden cable actuators can provide a range of maximum cable travel lengths, such as 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, and 50 mm. As discussed above, different levels of actuation could be required depending on the adjustment device being manipulated, and one actuator  12  could have one maximum cable travel length  44  while the other actuator  14  could have the same or different maximum cable travel length  46 . 
   As illustrated in  FIG. 2 , the dual drive actuation device  10  can be installed in a seat  48  with a four-way lumbar system  50 . Referring simultaneously to both  FIGS. 2 and 8 , one can see that the dual drive actuation device  10  may be positioned in any portion of the seat  48 . Similarly, as illustrated in  FIG. 3 , the dual drive actuation device  10  can be installed in a seat  48  with a bolster system  52 . The dual drive actuation device  10  can generally be used to manipulate the seat back  54  and seat cushions  56 . The dual drive actuation device  10  can also be used to manipulate a headrest  58 . 
   Another embodiment of the dual drive actuation system  10  with a bolster system is illustrated in  FIG. 6 .  FIG. 6  shows a pair of dual drive actuation devices  10  that are used to manipulate the seat back  54  and seat cushions  56 . The headrest  58 , as shown in  FIG. 6 , has a pair of support springs. The pair of dual drive actuation devices  10  can be oriented in any position allowing user comfort, seat stability, and lumbar control. 
   Another embodiment of the dual drive actuation system  10  is illustrated in  FIG. 4 . In the embodiment illustrated in  FIG. 1 , the solenoid  30  moves the position  26  of the beveled driver gear  28  to selectively engage the actuators  12 ,  14 . In comparison, according to general aspects of the embodiment in  FIG. 4 , the solenoid  30  moves the position  60  of the actuators  12 ,  14  to selectively engage the worm driver gear  62 . As illustrated by both embodiments, the power  64  for the motor  32  that drives the actuators  12 ,  14  can be separate from the solenoid control  66 . Generally, the worm driver gear  62  and the beveled driver gear  28  form part of a drive unit which engages the motor  32  and transfers its power to the actuators  12 ,  14 . Accordingly, the drive unit can be any type of driver gear  28 ,  62  or other driver unit or their equivalents that engage the motor  32  and transfers its power to the actuators  12 ,  14 . The solenoid  30  uses a transmission system to change the positions  26 ,  60  and thereby switch the driving force supplied by the motor  32  to each individual actuator  12 ,  14 . In the first embodiment, the drive shaft  20  serves as the transmission for moving the driver bevel gear  28 . In the second embodiment, a pinion link  68  serves as the transmission to move the actuators  12 ,  14 . The pinion link  68  connects one end of the actuators  12 ,  14  which are on either side of the worm driver gear  62 . Each one of the actuators  12 ,  14  has a threaded rod  70 ,  72  in screwed engagement with a respective threaded block  74 ,  76 . Each one of the threaded rods  70 ,  72  has a worm gear  78 ,  80 . 
   In operation, the solenoid  30  moves the position  60  of the pinion link  68 , which is connected to and moves the ends of the threaded rods  70 ,  72  to selectively engage the respective worm gears  78 ,  80  to the driver gear  62 . The motor  32  has a shaft  82  that drives a spur gear  84 . The driver gear  62  is attached to and rotates with the spur gear  84 . Therefore, when either one of the worm gears  78 ,  80  is engaged with the driver gear  62 , the respective threaded rod  70 ,  72  is rotated and the corresponding threaded block  74 ,  76  translates along the length of the actuator  12 ,  14 . 
   The threaded blocks  74 ,  76  have brackets  86 ,  88  that can attach to the end of a cable  90 ,  92  or another linkage between the actuators and the seat adjustment device. The dual drive  10  illustrated in  FIG. 4  provides another type of modular design for the actuators  12 ,  14 . Of course, the actuators  12 ,  14  could have different lengths depending on their usage, thereby limiting the maximum extension of the cables  90 ,  92  that is provided by the threaded rods  70 ,  72 . Additionally, even if the threaded rods  70 ,  72  have the same length, the actuators  12 ,  14  can provide a range of limits for the maximum extension using electronic controls. For example, the actuators  12 ,  14  can use the position of the threaded block  74 ,  76  in combination with a potentiometer or switch  94 ,  96  as a limit on the maximum extension. 
   Another embodiment using the worm driver gear arrangement of the dual drive actuation device  10  is shown in  FIG. 7 .  FIG. 7  shows a pair of dual drive actuation devices  10  that are used to manipulate the seat back  54  and seat cushions  56 . The headrest  58 , as shown in  FIG. 7 , has a pair of support springs. The pair of dual drive actuation devices  10  can be oriented in any position allowing user comfort, seat stability, and lumbar control. 
   In view of the foregoing, it will be seen that the several advantages of the invention are achieved and attained. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. 
   As various modifications could be made in the constructions and methods herein described and illustrated without departing from the scope of the invention, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. For example, although the drive shaft has a double-sided bevel gear attached at one end, a pair of bevel gears with opposing faces could alternatively be attached to the drive shaft. Similarly, although a solenoid is used within the control unit, a “muscle cable” or any other type of switch device or their equivalents could be used. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents.