Abstract:
A one-piece seat back frame for a seat assembly and method of forming includes a first member and an opposed second member spaced a predetermined distance apart. A third member extends between the first and second members. A fourth member is spaced a predetermined distance from the third member and has an initial predetermined dimension that is over-sized a predetermined amount to form an excisable slip plane portion, and a final predetermined dimension after the excisable portion is removed and free ends rejoined, so that the one-piece seat back frame can be adjusted prior to rejoining the free ends. The methodology removes the excisable portion, attaches a component to the frame, aligns the component by manipulating the fourth member free ends in the slip plane and rejoins the fourth member tree ends.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of and priority to U.S. Provisional Application No. 61/432,664, filed Jan. 14, 2011, which is incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    The present disclosure relates generally to the field of vehicle seats and more particularly, to a one-piece seat back frame having an integral slip plane, method of manufacturing and assembling components thereto. 
         [0003]    A vehicle seat back frame is typically made from a plurality of metal members arranged to form a structural frame. These members may be in the form of tubes and sheets that are generally formed into a particular shape, such as by bending, stamping piercing, drawing and welding or the like. During the manufacturing process the metal members are coupled together to form a rectangular frame. Further downstream the manufacturing process, a series of secondary operations are performed to further customize the seat back frame and add additional components, such as a recliner mechanism. These secondary operations are performed in several successive operations performed at different workstations, which complicates the manufacturing process and necessitates transfers from one workstation to the next. These secondary operations can be problematic to implement and pose a number of issues. For example, once a seat back frame has been formed it can be difficult to properly attach and align additional components, such as recliner mechanisms, to the seat back frame because the seat back frame has already been formed. These issues may be particularly evident when manufacturing a one-piece seat back frame. To rectify such misalignments, the seat back frame may need to be reworked or even scrapped which may increase manufacturing costs, reduce manufacturing efficiency, reduce seat back quality and performance, etc. 
         [0004]    Thus, there is a need to provide a seat back frame and method of manufacturing and assembling the seat back frame that provides the ability to adjust the alignment of seat back components during the manufacturing process while maintaining the cost and mass benefits of a one-piece stamped seat back frame. 
       SUMMARY 
       [0005]    Accordingly, the present disclosure relates to a one-piece seat back frame for use in a vehicle seat assembly. The one-piece seat back frame includes a first member and an opposed second member spaced a predetermined distance apart, and a third member extending between the first member and second member. The one-piece seat back frame also includes a fourth member spaced a predetermined distance from the third member and extending between the first member and second member. The fourth member has an initial predetermined dimension that is over-sized a predetermined amount to form an excisable portion, and a final predetermined dimension after the excisable portion is removed and free ends rejoined so that the one-piece seat back frame can be adjusted prior to rejoining the free ends. The excisable middle portion facilitates manufacturing and customization of the seat back frame. 
         [0006]    Also provided is a method of forming a one-piece seat back frame for use in a vehicle seat assembly. The method includes the step of providing a one-piece seat back frame having a first member, an opposed second member, a third member extending between the first member and second member and a fourth member spaced a predetermined distance from the third member and extending between the first member and second member. The fourth member has an initial predetermined dimension that is over-sized a predetermined amount to form an excisable portion. The method also includes the step of removing the excisable portion from the fourth member. The method further includes the steps of attaching a component to the one-piece seat back frame and adjusting the one-piece seat back frame to align the component by manipulating the free ends of the fourth member. The method still further includes the steps of rejoining the free ends of the fourth member, such that the fourth member has a final predetermined dimension after free ends are rejoined. 
         [0007]    An advantage of the present disclosure is that the one-piece seat back frame and method of manufacturing the one-piece seat back frame enable relatively easy attachment, adjustment and realignment of other components thereto. Another advantage of the present disclosure is that the one-piece seat back frame can be further customized relatively easily. A further advantage of the present disclosure is that the one-piece seat back frame has a relatively low mass and is relatively inexpensive to manufacture. 
         [0008]    Other features and advantages of the present disclosure will be readily appreciated, as the same becomes better understood after reading the subsequent description taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a perspective view of a vehicle. 
           [0010]      FIG. 2  is a perspective view of a seat assembly for the vehicle of  FIG. 1 . 
           [0011]      FIG. 3  is a front perspective view of a one-piece seat back frame for the seat assembly of  FIG. 2 . 
           [0012]      FIG. 4  is a rear perspective view of the one-piece seat back frame of  FIG. 3 . 
           [0013]      FIG. 5A  is a front view of a one-piece seat back frame. 
           [0014]      FIG. 5B  is a cross sectional view of the one--piece seat back frame of  FIG. 5A  along the A-A line. 
           [0015]      FIG. 6A  is a front view of the one-piece seat back frame of  FIG. 3  with the lower cross portion cut in two portions. 
           [0016]      FIG. 6B  is a cross sectional view of the one-piece seat back frame of  FIG. 6A  along the B-B line. 
           [0017]      FIG. 7A  is a front view of the one-piece seat back frame of  FIG. 4  with the two portions of the lower cross member rejoined. 
           [0018]      FIG. 7B  is a cross sectional view of the one-piece seat back frame of  FIG. 7A  along the C-C line. 
           [0019]      FIG. 8  is a flow chart of the methodology of customizing a one-piece seat back frame and attaching components thereto, according to an exemplary embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    Referring generally to the FIGURES and particularly to FIG,  1 , a vehicle  10  is shown according to an exemplary embodiment. The vehicle  10  can include one or more seat assemblies  12  provided for an occupant of the vehicle  10 . While the vehicle  10  shown is an automobile, it should be understood that the seat  12  may be used in any type of vehicle used to accommodate a seated occupant, including a passenger vehicle, train, airplane, boat or any other means in or by which someone travels or something is carried or conveyed. 
         [0021]    Referring now to  FIG. 2 , a seat assembly  12  is shown. The seat  12  illustrated is a occupant seat typically used in front row of a vehicle, but the seat structures of the present disclosure may be incorporated into any vehicle seat, such as a second row seat, a second row bench, a third row, or the like, which may utilize any type of seat functionality. Further, the seat assembly  12  could also be utilized as a stand-alone seat assembly, such as for an office seat, theatre seat or any other contemplated use of a seat. 
         [0022]    The seat assembly  12  includes a seat back  14  operatively connected to a seat base  16 . The seat back  14  and seat base  16  includes a seat frame  28  and a seat cover  24  overlying the seat frame  28 . A padding (not shown) may be disposed between the seat frame  28  and seat cover  24  to provide a desired shape and support to the seat. The seat base  16  may include a seat cushion  26 , The seat back  14  and seat cushion  26  provide comfort, support and protection to a seated occupant (not shown). The seat  12  may also include a head restraint  18  positioned at an upper end of the seat back  14 , and operatively connected thereto. The head restraint  18  extends upwardly from the seat back  14  and is configured to provide support and restrain the head of an occupant. The seat back  14  may be pivotally coupled to the seat base  20  via an actuator  20 , such as a recliner mechanism, that provides rotatable adjustability between the seat back  14  and the seat base  16 . The seat assembly  12  can also be secured to the vehicle  10  using a track assembly  22 . In this example, the track assembly  22  enables the seat assembly  12  to be repositioned relative the vehicle floor to enhance comfort and utility. 
         [0023]    Referring to  FIGS. 3 and 4 , the seat back  14  includes a one-piece seat back frame  28 . The one-piece back frame  28  is stamped from a single piece of material and includes an integrally formed slip plane. The one-piece back frame  28  includes a generally planar first member, which in this example is a first side member  30  having an upper end  32  and lower end  34 . The one-piece back frame  28  includes an opposed generally planar second member or second side member  36  of this example having an upper end  38  and lower end  40 . The one-piece seat back frame  28  also includes a generally planar third member or upper cross member  42  in this example having a first end  44  and an opposed second end  46 . The upper cross member  42  is located between the upper end of first side member  32  and the upper end of the second side member  38 . The one-piece back frame  28  further includes an opposed, generally planar fourth member, which in this example is a lower cross member  48  having a first end  50  and a second end  52 , and is disposed between the lower end of the first side member  34  and the lower end of the second side member  40 . The first side member  30 , the second side member  36 , the upper cross member  42  and lower cross member  48  are integrally formed as a substantially rectangular one-piece back frame  28 . The one-piece back frame  28  has a front surface  54  and a rear surface  56 . The front and rear surfaces  54 ,  56  respectively may have a substantially flat contour, but may also include have a variety of localized profiles, contours, features, or the like, as needs or performance requirements dictate. 
         [0024]    The one-piece seat back frame  28  also includes an extended portion, as shown at  29  that is intentionally over-sized a predetermined dimension with respect to a predetermined finished dimension. The extended portion  29  forms an integral slip plane to facilitate manufacturing and customization in a manner to be described. For example, as shown in  FIG. 5A , the lower cross member  48  may include an initial over-sized portion  29  having a predetermined initial dimension, which in this example is the overall length, forming a first portion  48 A, a second portion  48 B, and a third portion  48 C extending therebetween the first portion  48 A and second portion  48 B. The third portion  48 C can later be cut or excised from the lower cross member later (such as, downstream in the manufacturing process, or the like) to facilitate the method of forming and customizing the one-piece seat back frame  28  as will be described in further detail below. In another example, the third portion or segment  48 C can be in the form of a tab that interconnects the first portion  48 A and the second portion  48 B, and which can be cut or removed at some predetermined point later during the process, such as, during stamping, during assembly, during manufacturing, or the like. 
         [0025]    The one-piece back frame  28  may also include an inner side wall  58  extending circumferentially around a portion of an inner edge  60  of the front surface  54 . The one-piece seat back frame  28  may also include an outer side wall  62  extending circumferentially around a portion of the outer edge  64  of the front surface  54  to cooperatively form and define a generally U-shaped channel  66 , The one-piece back frame  28  can also have an over-sized portion forming an angled portion  68  that is located in either one of the first side member  32  or second side member  36 . In this example, the angled portion  68  is located nearer the lower cross member  48 . 
         [0026]    The one-piece back frame  28  may include a feature such as a lower cross bracket member, pivot bracket, recliner, or the like, can also include a surface features or structure  70 , such as, ribs/stiffeners, beads, darts, protrusions, elevations, depressions, deformations, stampings, openings, or the like. Such surface features  70  may be formed as part of or integral with the back frame  28  to enhance the strength and rigidity performance of the seat back frame  28  without significantly increasing the mass thereof. The number, length, shape, width, dimensions, position, location, orientation, or the like, of the surface features  70  can vary as appropriate and/or as needed to optimize strength, stability and performance of the one-piece back frame  28 . In this example, a vertically extending rib  72  is formed in a portion of each of the first side member  30  and second side member  36  to enhance the fore/aft stiffness of the one-piece back frame  28 . The complexity of these features  70  can vary depending on the type of material used for the one-piece back frame  28 . Generally, the complexity of the geometries may be increased with the use of lower strength material. The one-piece back frame  28  may also include a plurality of openings  74 , such as, holes, extruded holes, apertures, grooves, channels, passageways, or the like, and interface/surface areas  76  for attachment of other components, such as, recliner mechanisms, recliner plates, recliner shafts, foam, trim covers, head restraints, or the like. The one-piece back frame  28  may also include a plurality flanges  78  extending from the inner and outer side walls  58 ,  62  that provide stiffness to the structure, durability for the seat foam/upholstery, reduced sharp edges, and attachment/resting surfaces for other components, such as, foam, trim cover, or the like. 
         [0027]    The one-piece seat structure can be formed from various materials, such as, tailor welded blanks, tailor welded coils, monolithic blanks or coils having uniform or non-uniform material grade and thickness, or the like. The one-piece seat structures can be formed from a variety of steel grades and types, such as, HSLA, AHSS (Dual Phase, Complex Phase, TRIP, post form heat treatable steel, such as, aluminum, magnesium, or the like). The materials used can be optimized depending on various factors, such as, the type of structure or portion to be made, the location of the structure or portion, the geometry requirements of the structure or portion, the strength requirements of the structure or portion, or the like. For example, lower strength materials typically have higher formability which enable incorporation of more (or higher complexity) geometry in the design of a structure or portion, but may require greater thickness to recover strength lost by using lower strength material. The formability and strength of the material can be optimized and balanced according to the needs dictated by the type of structure or portion and its location within the seat assembly. 
         [0028]    Referring now to  FIG. 8 , a method of forming and customizing the one-piece seat back frame  28  of  FIGS. 2-7  is shown. The method begins at Step  210  whereby a one-piece seat back frame  28  is formed. The one-piece seat back frame  28  may be formed using any forming process, such stamping. The one-piece seat back frame  28  includes a lower cross member  48  that initially has an over-sized portion  29  with an integrally formed slip plane  29 . While in this example the over-sized, portion  29  is in the lower cross member, the over-sized portion could be formed in any of the members of the one-piece seat back frame  28 . The excess material  48   c  is greater than the final or finished dimension of the lower cross member, in terms of length, width, or the like, as shown in FIG,  5 A and  5 B. For example, the lower cross member  48  can have an initial predetermined excess length of 5 to 10 mm. 
         [0029]    The method proceeds to Step  220  wherein the portion of excess material  48 C is removed from the lower cross member  48 , such as via a cut, or the like, such as during stamping, as shown in  FIG. 6A and 6B . To facilitate this step, the one-piece back frame  28  can be positioned into a fixture, such as a fixture for welding secondary components thereto, or the like. Once in the fixture, the portion of excess material  48 C can be removed using a predetermined excision technique, such as laser cutting, stamp cutting, die cutting, or the like. Once the portion of excess material  48 C is cut, the first portion  48 A and the second portion  48 B are disconnected and separated, and each have a free edge,  48 A′ and  48 B′ respectively. The separation between the first portion  48 A and second portion  48 B, enables the first portion  48 A and the second portion  48 B to be independently manipulated, maneuvered, adjusted, or the like. This freedom of movement thereby facilitates attachment of other components to the one-piece seat structure, such as a recliner mechanism, or the like. 
         [0030]    The method proceeds to Step  230  wherein additional components, such as recliner mechanisms, or the like, are subsequently attached to the one-piece seat back frame  28  during assembly. In this example, a recliner mechanism is attached to the lower cross member first portion  48 A and another recliner mechanism is attached to the lower cross member second portion  48 B. The attachment may be semi-permanent, so that the relative orientation of the additional component may be adjusted. 
         [0031]    The method proceeds to Step  240  wherein the additional component is permanently secured to the one-piece seat back frame  28 . The component, such as a recliner mechanism, may be secured to the one-piece seat back frame  28  using a predetermined technique such as welding, fastening, bolting, screwing, or the like. 
         [0032]    The method proceeds to Step  250  wherein the first portion  48 A and the second portion  48 B are adjusted and rejoined, and the first portion edge  48 A′ and second portion edge  48 B′ are properly aligned with one another in a predetermined manner. For example, the first portion  48 A and the second portion  48 B can be repositioned adjacent to one another such that a portion of the first portion and the second portion overlap one another, as shown in  FIG. 7A and 7B  at  80 . 
         [0033]    The method proceeds to Step  260  wherein the overlapped portion  80  of the first portion  48 A and the second portion  48 B are secured together using a predetermined joining technique, such as welding, fastening, bolting, screwing, or the like. In this example, the first portion  48 A and the second portion  48 B are laser welded together. 
         [0034]    The one-piece may be finished in a finishing operation. For example, additional steps can be performed to further customize the one-piece seat back frame. Additional components can be attached to the one-piece seat back frame, such as reinforcement brackets, head restraint components, or the like. Also, surface features can be created, such as ribs for added strength and rigidity, cutting openings for attachments, or the like. It should be noted that while this example a lower cross member includes an over-sized portion, the method can be used with a frame  28  having other over-sized portions or multiple over-sized portions, such as an upper cross member, side member, or the like. Moreover, the method can be modified in various manners, such as by adding one or more steps, removing one or more steps, changing the sequence of the steps, or the like. 
         [0035]    Many modifications and variations of the present disclosure are possible in light of the above teachings. Therefore, within the scope of the appended claim, the present disclosure may be practiced other than as specifically described.