Abstract:
An actuator for a lumbar support device possessing a symmetrical housing in that key holes are present on both sides of such housing. The present invention&#39;s housing, with key hole slots diametrically opposed on one end, allows the actuator to be installed more easily in any orientation, in either driver or passenger side seats. With the dual key hole housing, the extra time and effort associated with ensuring that the correct side of the housing is being used is eliminated as the dual key holes allow the tension cable wire and tension cable wire end to be inserted into either side of the housing during assembly of the lumbar support system. The elimination of this concern will save valuable time and money in the actuator assembly process.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     This invention relates generally to actuators and, more particularly, to actuators used in connection with a tension cable wire for use primarily in lumbar support systems for automobile car seats. The actuator disclosed here is designed to speed and streamline assembly of actuators with Bowden cables, lumbar supports, and seat frames.  
         [0003]     2. Related Art  
         [0004]     It is well known in the art to use an actuator in connection with a tension cable wire to provide movement in a lumbar support device located within a seat frame. Normally, the tension cable wire used in this type of configuration is a Bowden cable. A Bowden cable consists of a wire with wire ends on each side. The wire slides axially through a wire covering, sometimes referred to as a sleeve or conduit. In order to provide tension, the wire end is normally attached to a moving part while the wire covering is attached to a stationary unit. The moving part extends the wire end away from the wire covering end, thus creating a corresponding movement of the other wire end relative to the other sleeve end. The movement is used to actuate the lumbar support device. The movement is typically under tension.  
         [0005]     It is also known in the art to use an actuator that employs the use of a threaded screw as the moving part that separates the tension cable wire end from the tension cable wire covering. Such an actuator generally contains a nut, which is also threaded, whereby as the nut is turned, the screw moves axially through the nut. One end of such screw normally has an aperture for the placement of a tension cable wire end. Somewhere near this aperture is also a stopper. The stopper prevents the tension cable wire covering end from extending with the tension cable wire end as the screw is directed away from the stopper. Such examples of these types of inventions are disclosed in U.S. Pat. No. 5,638,722 to Klinger, U.S. Pat. No. 6,053,064 to Gowing et al., and U.S. Pat. No. 5,771,751 to Schwarzbich.  
         [0006]     Furthermore, a two screw system has also been previously disclosed whereby each screw contains oppositely threaded sections so that when the nut is rotated, the screws move simultaneously either closer or farther away from one another depending upon the direction the nut is rotated. See U.S. application Ser. No. 10/008,896 to Robert McMillen and PCT application PCT/US02/39076 to Robert McMillen. In this type of system, the stopper is generally contained on one screw while the aperture for receiving the wire end is contained on the other screw. Such a configuration allows for the same distance of movement between the tension wire cable end and the tension wire cable covering as in the single screw configuration; however, such a result is obtained with fewer turns of the nut. This advantage allows the car seat occupant to adjust the lumbar support system to the desired level of support while exerting a lesser amount of energy to accomplish the adjustment.  
         [0007]     All of these inventions rely on some type of actuator to provide the movement necessary to produce the required tension at the opposite end of the tension wire cable needed to actuate the lumbar support device. Actuators are generally oriented in seat frames with a tab in the housing that is asymmetrical and designed to correspond with a slot in a seat frame hole provided for the actuator, or alternatively, a mounting grommet with a similar slot. Proper orientation is required for proper alignment with lumbar support components, Bowden cable routing, and consistency with left or right side seat assembly.  
         [0008]     Many actuator housings employ the use of key hole apertures for mounting a tension cable wire end. The key holes are slots with a wide dimension designed to receive tension cable wire ends, and the bullet typically fixed to the wire end. A narrow neck of the key hole is designed to allow insertion of a tension cable wire while holding the end bullet against axial tension.  
         [0009]     Previous actuators with single key holes in asymmetric housings cause improper installation and assembly confusion, when used as “snap-in” components. During the assembly process, workers must spend extra time and effort to ensure that the side of the housing that possesses the key hole is lined up properly with the wire end aperture such that the tension cable wire end can be properly inserted into the wire end aperture. This results in a relatively large amount of lost time in the assembly process and also leads to improper installation and confusion in the assembly of the actuators. There is a need in the art for an actuator design that will speed and streamline the assembly process and will eliminate the improper assembly and confusion associated with the asymmetric housings.  
       SUMMARY OF THE INVENTION  
       [0010]     It is in view of the above problems that the present invention was developed. The invention is an actuator possessing a symmetrical housing in that key holes are present on both sides of such housing. The present invention&#39;s housing, with key hole slots diametrically opposed on both sides, allows the actuator to be installed more easily in any orientation, in either driver or passenger side seats. This is especially true in the screw type actuators described above. With the dual key hole housing, the extra time and effort associated with ensuring that the correct side of the housing is being used is eliminated as either side of the housing possesses the appropriate key hole. The elimination of this concern will save valuable time and money in the actuator assembly process.  
         [0011]     There is also an advantage of this invention that relates to an improvement in the quality of the lumbar support device in which it is used. During operation, the lumbar support device can move from a point with the least amount of lumbar support to a point with the maximum amount of lumbar support. The position of least support is known as the rest position. Ideally, in the rest position, the lumbar support will put little or no tension on the traction cable wire, but will also be aligned with a fully retracted position of the actuator. This ideal assembly coordination among lumbar support, traction cable and actuator eliminates any “play” or slack in the linkage, and thereby promotes a sense of responsiveness and precision that can be felt by a user and is valued in the marketplace.  
         [0012]     During the assembly process, access to the tension cable wire end receiver is blocked by the housing, unless the receiver is directly aligned with a key hole in the housing so that access to the receiver may be gained. As a result, the seat assembler may determine that the length of the tension cable wire end and its receiver do not match when the receiver is at the retracted position where the key holes align. Thus the matching wire length and receiver position to produce a resting assembly without slack or tension is not accessible at this length because there is no access to a key hole at this position. As such, the lead screw, which contains the receiver, must be rotated through the housing until the receiver aligns with the key hole. The more the lead screw is turned to accomplish this alignment, the greater the distance the receiver is moved from the ideal length, creating either unwanted tension or unwanted slack. Depending on the length calculated as being ideal, the lead screw of a single key hole actuator may have to be rotated as much as 180 degrees to achieve the proper alignment between the receiver and the key hole. However, the invention disclosed herein requires a maximum rotation of only 90 degrees to obtain the proper alignment of the receiver with one of the two key holes. Having dual key holes diametrically opposed on both sides of the actuator housing allows for proper alignment to be obtained with a smaller amount of rotation of the lead screw, which results in the receiver being closer to its ideal length when proper alignment is achieved.  
         [0013]     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  
       [0014]     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:  
         [0015]      FIG. 1  is a perspective view of the assembled actuator;  
         [0016]      FIG. 2  is a cut away perspective view of the actuator in combination with a Bowden cable;  
         [0017]      FIG. 3  are perspective views of the actuator housing;  
         [0018]      FIG. 4  is a cut away perspective and a cut away side view of the nut;  
         [0019]      FIG. 5  are perspective views of the upper lead screw; and  
         [0020]      FIG. 6  are perspective views of the lower lead screw. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0021]     Referring to the accompanying drawings in which like reference numbers indicate like elements,  FIGS. 1-6  are perspective and side views of the actuator of the present invention. Housing  10  has two flanges  38  with holes for anchoring screws so that the unit may be mounted in an automotive car seat frame. Located within the housing  10  is a nut  26 . The nut  26  can be rotated within the housing  10 . The nut  26  contains a first sets of threads  40  and a second set of threads  28  on its inside diameter (See  FIG. 4 ). The first set of threads  40  communicates directly with the upper lead screw  16  while the second set of threads  28  communicated directly with the lower lead screw  14 . More specifically, the first set of threads  40  engages with the corresponding threads  30  of the upper lead screw  16  and the second set of threads  28  engages with the corresponding threads  34  of the lower lead screw  14 .  
         [0022]      FIG. 2  is a cut away perspective view of the assembled actuator. The upper lead screw  16  contains a tension cable wire end receiver  18  for insertion of a tension cable wire end  62  for anchoring the wire. The lower lead screw  14  contains a tension cable sleeve stopper  20 .  
         [0023]     The upper lead screw  16  has threads  30  engaging the nut threads  40 , which threads are in a first direction. Whether this direction is right or left handed is immaterial, provided that the upper lead screw is threaded in the opposite direction from the second set of nut threads  28  and the threads  34  of the lower lead screw  14 . Thus configured, rotation of the nut  26  causes both lead screws  16  and  14  to extend relative to housing  10  and nut  26 , in opposite directions.  
         [0024]      FIG. 3  are two perspective views of the housing  10  of this actuator. The figures show the dual key holes  24  possessed by the housing  10 . As seen in this figure, the key holes  24  are slots with a wide dimension designed to receive tension cable wire ends  62 , and a narrow dimension designed to allow insertion of tension cable wires  64 . In the depicted embodiment the two key holes  24  are located on the same end of the housing  10  and are diametrically opposed on both sides of the housing  10 . Such a configuration allows the tension cable wire end  62  and tension cable wire  64  to be inserted into the tension cable wire end receiver  18  after the actuator has been completely assembled. Moreover, the dual key hole configuration eliminates the need for the assembly worker to determine which side of the housing has the key hole  24  during assembly. The tension cable wire end  62  and tension cable wire  64  may be properly inserted into either key hole  24  as the lumbar support system is being assembled. The housing  10  described in this embodiment is used in connection with a two screw actuator. However, other embodiments of this invention may possess the dual key hole housing in connection with a one screw type configuration as disclosed in some of the prior art discussed above.  
         [0025]      FIGS. 4-6  are detailed illustrations of the nut  26 , the upper lead screw  16 , and the lower lead screw  14 . In order to achieve the tension required for movement of the lumbar support system, the nut  26 , the upper lead screw  16 , and the lower lead screw  14  are interconnected such that when the nut  26  is rotated in a certain direction, the upper lead screw  16  and the lower lead screw  14  are moved in an axial direction away from one another.  
         [0026]      FIG. 5  is a perspective view of the upper lead screw  16 . The upper lead screw  16  contains the tension cable wire end receiver  18  which is generally a type of aperture. The tension cable wire end  62  is attached to the upper lead screw  16  via the receiver  18 . While attachment may occur in a variety of manners currently known in the art, the depicted embodiment is configured such that a wire end bullet will seat in the lead screw key hole simply by placing it there. The upper lead screw  16  also contains a set of screw threads  30 . In this embodiment, the upper lead screw  16  possesses a shaft  32  that is inserted into the inner channel  42  of the lower lead screw  14 . The shaft  32  extends the tension cable wire end receiver  18  a certain distance so that it is properly aligned with one of the key holes  44  of the lower lead screw  14 .  
         [0027]      FIG. 6  is a perspective view of the lower lead screw  14 . From this figure, the inner channel  42  of the lower lead screw  14  is easily seen. This inner channel  42  allows the shaft of the upper lead screw  16  and the tension cable wire end receiver  18  to be located within the lower lead screw  14 . Such configuration allows for reduction of the overall size of the actuator and reduces the space needed for its operation. The lower lead screw  14  also contains a tension cable sleeve stopper  20 . The stopper  20  prevents the tension cable sleeve  60  from extending along with the tension cable wire end  62  as the wire end  62  is moved by the upper lead screw  16 . The stopper  20  is preferably a counter sunk region at an end of the screw  14 .  
         [0028]     Other features of the lower lead screw  14  include the two key holes  44  located at one end of the lower lead screw  14  so that the tension cable wire end  62  may be inserted into the tension cable wire end receiver  18 . In the depicted embodiment, the two key holes  44  are diametrically opposed on opposite sides of one end of the lower lead screw  14 . As in the housing  10 , the key holes  44  in the lower lead screw  14  allow for easier assembly of the lumbar support system as the tension cable wire end  62  and the tension cable wire  64  may be inserted into either key hole slot  44 . This feature is important where the actuator is designed so that the tension cable wire end receiver  18  extends within the lower lead screw  14 . With such a configuration, the tension cable wire  64  and the tension cable wire end  62  may not properly be inserted into the tension cable wire end receiver  18  as access to this area is blocked by the lower lead screw  14 . The key holes  44  in the lower lead screw  14  allow an assembler access to the tension cable wire end receiver  18  so that insertion of the tension cable wire end  62  into the tension cable wire end receiver  18  may be completed.  
         [0029]     As discussed earlier, the upper lead screw  16  and the lower lead screw  14  contain threaded portions  30  and  34 . These threaded portions  30  and  34  communicate directly with the nut threads  40  and  28  located on the interior of the nut  26 . When the nut  26  is rotated in one direction, the upper lead screw  16  and the lower lead screw  14  are moved apart from one another. When the nut  26  is rotated in the opposite direction, the upper lead screw  16  and the lower lead screw  14  are moved closer together. The outward movement of these two screws  14  and  16  results in the tension cable wire end  62  being separated from the tension cable sleeve  60 , thus producing the desired tension at the opposite end of the tension cable wire to actuate the lumbar support system.  
         [0030]      FIG. 4  also illustrates aspects of the invention that promotes ease of assembly. Nut  26  is split into two halves so that the upper lead screw  16  and lower lead screw  14  may be laid into their proper places in the threads on the inner aspect of nut  26 . Once the lead screws  16  and  14  are placed in their proper positions, the second half of the nut  26  is placed over the lead screws. After this has been completed, the assembler can take this part of the actuator and “snap” it into the housing  10 . Again, the advantage of the dual key hole housing  10  is seen at this point in the assembly process as the assembler is not required to take the time and effort to determine which side of the housing  10  has the key hole  24  and line it up with the tension cable wire end receiver  18 . Instead, the assembler may merely place the nut, upper lead screw, and lower lead screw assembly into the housing  10  knowing that the tension wire end receiver  18  will properly align with at least one of the two key holes  24 .  
         [0031]     In view of the foregoing, it will be seen that the several advantages of the invention are achieved and attained.  
         [0032]     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.  
         [0033]     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, even though this actuator is primarily intended to be used in conjunction with a lumbar support device in an automotive car seat, it can be used to provide tension in any type system employing the use of a tension wire cable. Similarly, although the dual key hole housing is used in connection with a two screw actuator in this embodiment, it can also be used with a single screw actuator or any other type actuator using an aperture for the placement of a tension cable wire end. 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.