Patent Publication Number: US-2004056527-A1

Title: Clamp for a lumbar support

Description:
[0001] This invention relates to a clamp for attaching a component to an elongate member such as to a post. The clamp may form part of or be attachable to the component. In a particular application of the invention, the component is a lumbar support for use in the backrest of a seat or chair and the clamp is for attaching the lumbar support to a post portion of a frame of the seat or chair.  
       [0002] The invention will be particularly described with reference to the attachment of a lumbar support to a vehicle seat frame. However it is to be understood that the clamp may be used for other applications.  
       [0003] It is known to provide lumbar supports in vehicle seats and especially in the seat to be occupied by the vehicle driver. Such supports are usually adjustable and take a variety of forms, and the manner of achieving adjustment also varies. The adjustment, when present, is generally such that it varies the effective length of the lumbar support and/or its stiffness, and thereby influences the extent to which the support curves rearwards in response to pressure applied by the user of the vehicle seat. That is, the lumbar support may provide a relatively flat or a deeply curved support for the vehicle seat occupant, according to the level of adjustment of the effective length of the support.  
       [0004] It will be appreciated that relatively high forces can be imposed on a lumbar support by both the seat occupant and via an adjustment mechanism for adjusting the support. Thus the lumbar support must be securely attached to the vehicle seat frame. Additionally the cost of manufacturing a suitable attachment means for a lumbar support and its convenience of installation are significant factors for the commercial viability of a lumbar support.  
       [0005] The present invention seeks to provide a clamp for attaching a component to an elongate member, such as to a post, for example a lumbar support to a frame of a seat, which is relatively cheap to manufacture and convenient to install whilst enabling a firm attachment of the component to the elongate member.  
       [0006] According to the invention there is provided a clamp for attaching a component to an elongate member (hereinafter referred to for brevity as “a post”), the clamp forming part of or being attachable to the component and having first and second reinforced portions joined by a flexible portion for surrounding the post, the first and second reinforced portions each including a concave section and an extension section, wherein in use the extension sections are engageable for the concave sections to oppositely contact the post, and wherein the extension sections include complementary locating means for aligning an aperture in each extension section for passage of a fastener and for preventing relative lateral movement between the extension sections.  
       [0007] Preferably one of the extension sections includes an integrally formed flexible extension strap to which the component is attachable or attached.  
       [0008] Preferably the clamp is an integral structure formed, for example by moulding, from a suitably strong plastics material such as nylon. More preferably the component is a lumbar support in the form of a band or like structure which is integrally formed with a clamp of the invention at each end of the support for connection to opposite side members or post portions of the frame of a seat backrest. It will be understood that the lumbar support is of a type which is in the form of a flexible band or like structure which extends across the seat backrest. Examples of such lumbar supports are disclosed in WO 94/08492 (PCT/AU93/00521) and WO 98/09835 (PCT/AU97/00480).  
       [0009] In one preferred form of the invention, the clamp is adapted to make principal contact with the periphery of the post at three locations. A first of these locations is at the flexible portion. The other two portions are closely adjacent to each other and each is at a respective one of the extension sections. With the extension sections engaged for securement of the clamp with a post, one extension may fit into the other such that respective edges overlap to define an included angle therebetween. In such case, each of the other locations is defined by such edge of the respective extension section. The arrangement is such that the first location makes contact with a side of the post which is opposite to a side contacted by the other two locations.  
       [0010] Preferably each concave section of the reinforced portions includes at least one ridge which extends transversely of the clamp, that is, in use the ridges extend along the post. Such ridges provide further or secondary locations at which the clamp contacts the post. As such, they can assist the rigidity of the attachment of the clamp to the post, particularly when a turning moment is applied to the clamp via, for example, a force on the component.  
       [0011] The clamp most preferably is able to accommodate a degree of variation in the cross-sectional dimensions and form of posts with which it is intended to be used. For this, the complementary locating means of the extension sections preferably are engaged for effective clamping over a range of relative positions. Thus, for example, with the preferred form of the invention referred to above, the extension sections can engage by the one extension fitting into the other over a range necessary to bring each of their overlapping edges into contact with the post. For this, the extension sections engage in a manner which retains the overlapping edges at a suitable included angle throughout the range of fitting of the one section into the other.  
       [0012] The reinforced portions may be provided by a ribbed structure which may be provided on the outwardly facing surface of the reinforced portions in which case the aforementioned ridges may be provided on a continuous inner surface. Alternatively the rib structure could be inwardly facing on at least one of the reinforced portions such that the ridge of that structure is discontinuous. Such a discontinuous ridge arrangement provides a number of pressure points in contact with the post when the clamp is attached thereto, which assists the firmness of the clamping attachment.  
       [0013] Preferably one of the reinforced sections includes a protrusion such as a pin or like means which extends from the concave section for engaging a complementary aperture or recess in the post. This retains the clamp at a required position along the post while, particularly with a post of substantially circular cross-section, it may also serve to prevent any relative turning of the clamp on the post in use of the clamp. The protrusion may be selected so that the clamp is “handed”, such that the protrusion of each clamp at a respective end of lumbar support will engage only in the aperture of its respective post. Thus, the protrusion or protrusions of each clamp can ensure that the lumbar support is correctly secured to the seat-back frame.  
       [0014] Preferably the extension section of each reinforced portion of the clamp includes surfaces which, in use of the clamp, can be brought into facing contact by tightening a fastener which passes through the aligned apertures. Preferably these apertures through which a fastener may pass extend from each such facing surface.  
       [0015] The complementary locating means preferably include webs or ribs associated with the facing surface of one of the extension sections and recesses or grooves, for receiving the webs or ribs, extending from the facing surface of the other extension section. Additionally, one of the extension sections may include flanges which extend normally from each edge of the clamp and between which the other extension section is received. Such flanges are particularly suitable for guiding the other extension section as it moves towards the first for alignment of the apertures and for preventing lateral movement of one extension section relative to the other. Preferably the aforementioned flexible extension strap, to which the component is attachable or attached, extends from the extension section which includes the flanges. 
     
    
    
     [0016] For a better understanding of the invention and to show how it may be carried into effect, a preferred embodiment thereof will now be described, by way of non-limiting example only, with reference to the accompanying drawings.  
     [0017] In the drawings  
     [0018]FIG. 1 shows a perspective view of a lumbar support attached to the frame of a seat using clamps according to a first embodiment of the invention;  
     [0019]FIG. 2 shows a clamp of the first embodiment of the invention in an opened condition;  
     [0020]FIG. 3 shows the clamp of FIG. 2 in a closed condition; and  
     [0021]FIG. 4 is a partial perspective view of a lumbar support attached to one side of a seat frame and showing a clamp of a second embodiment of the invention. 
    
    
     [0022] In FIG. 1, a lumbar support  10  of the flexible band type extends between two side members, comprising posts  12 , of a partially shown seat backrest frame and is attached to the posts  12  by clamps  14 . The lumbar support  10  includes a band  16  and a number of curved profile sections  18  which are attached to or form part of the band  16 . It also preferably includes an adjustment mechanism (not shown). The lumbar support  12  is known, see for example WO 94/08492, and will not be described in further detail herein. Also, it is to be understood the invention is applicable to lumbar supports other than the example shown in FIG. 1.  
     [0023] A preferred clamp  14  according to the invention is moulded from a plastics material such as nylon and preferably is integrally formed with the lumbar support  10 . As shown in FIGS. 2 and 3, the clamp  14  includes a first reinforced portion  20  and a second reinforced portion  22  joined by a flexible portion  24 . The reinforced portions  20  and  22  each include a concave section  26 ,  28  respectively, and an extension section,  30  and  32  respectively. The concave sections  26 ,  28  have a profile which is complementary to the cross-sectional shape of the posts  12  of the seat frame. This cross-section is generally non-circular and, for example, it may be oval (as shown), or somewhat rectangular.  
     [0024] Each extension section  30 ,  32  of the reinforced portions  20 ,  22  includes a surface  34 ,  36  respectively. In use of the clamp  14 , surfaces  34  and  36  are brought into facing proximity, if not contact, to enable a respective clamp  14  to be disposed around each post  12 , as shown in FIG. 1. When so disposed, the concave sections  26 ,  28  and flexible portion  24  of each clamp  14  provide a passage (see FIG. 3) which substantially conforms to the cross-section of the respective post  12  such that the concave sections  26 ,  28  oppositely contact the post  12 .  
     [0025] Each extension section  30 ,  32  includes an aperture  38 ,  40  respectively, which extends therethrough from each of respective surfaces  34  and  36 . The extension sections  30 ,  32  furthermore include complementary locating means for aligning the apertures  38 ,  40  and for preventing relative lateral movement between the extension sections. These complementary locating means include upstanding webs  42  on extension section  30  (only one of which is visible in FIG. 2) which are receivable in recesses  44  formed in extension section  32 . The recesses  44  have a relatively wide opening at surface  36  and walls which taper towards each other away from surface  36  to assist in the alignment of the extension sections  30  and  32  as they are moved relatively towards each other to assemble the clamp  14  around a post  12 . The reinforced portion  20  includes an upstanding cross wall  46  which effectively defines the junction between the concave  26  and extension  30  sections of the reinforced portion  20 . A shoulder  48  formed on the other extension section  32  and which defines an edge  36   a  of the surface  36  is able to bear against a surface of wall  46  which faces across extension section  30 , to further provide for positive location of the extension sections  30  and  32  as they are moved relatively towards each other. The extension section  30  furthermore includes side flanges  50  between which the extension section  32  locates thus preventing it from moving laterally of the extension section  30 .  
     [0026] Reinforcement of portions  20  and  22  is enhanced by a ribbed structure  52 ,  53  respectively for each portion. The ribbed structure  52  is located inwardly of reinforced portion  20 , while the outer surface (not shown) of portion  20  may be continuous. The rib structure  53  is located outwardly of reinforced portion  22 , while the inner surface  54  of portion  22  is continuous. Inner surface  54  has major portions  54   a ,  54   b ,  54   c  and  54   d , with portions  54   a ,  54   b  and  54   c  substantially parallel and surface  54   b  recessed relative to portions  54   a  and  54   c.    
     [0027] The concave section  28  of reinforced portion  22  includes two continuous transverse ridges  56  and  57 . Ridge  56  is located between surface portions  54   a  and  54   b , while ridge  57  is located between portions  54   b  and  54   c . The concave section  26  of reinforced portion  20  includes two discontinuous transverse ridges  58  and  59 , each formed partly by a mid-section of ribbed structure  52  being set back from end sections thereof. The ridges  56  and  57  and the series of ridges  58  and  59  tightly bear against the surface of a post  12  when the clamp is attached thereto. These ridges assist the rigidity of attachment of the clamp  14 .  
     [0028] Location of a clamp  14  relative to a post  12  is by means of an inwardly directed projection  60  on the concave section  26  of the reinforced portion  20 . This projection  60  is for location in a complementary hole in a side member  12 .  
     [0029] The band  16  of the lumbar support  10  preferably is integrally joined to the extension section  30 . Alternatively, the clamp may be formed with a short, integral extension, such as the part to which reference  16  in FIGS. 2 and 3 extends, and a component such as a lumbar support attached to the clamp via that extension.  
     [0030] In use, the clamp  14  at each end of a lumbar support  10  is fitted around a respective post  12  and affixed thereto by passing a fastener such as a bolt (not shown) through the aligned apertures  38 ,  40  and tightening the bolt. As illustrated in FIG. 1, the engaged extension sections provide anchorage locations  62  for the lumbar support  10  which are located forwardly of the posts  12 .  
     [0031] The band  16  may project beyond the end of either of extension sections and  32  which is remote from the respective one of concave sections  26  and  28 . However, as indicated, extension section  32  fits partly within extension section  30  and it therefore generally is more convenient to have band  16  extend from extension section  30 , as shown. In any event, it is preferred that clamp  14  is mounted on post  12  such that the extension section from which band  16  projects is on the laterally outer side of post  12  (as also shown), as this better resists tension in band  16 .  
     [0032] As will be appreciated, each clamp  14  of the lumbar support  10  is secured to a respective post  12  of the seat back-rest frame by being presented to its post in the general orientation shown in FIG. 2. The projection  60  of the clamp  14  is located in a hole in the respective post  12 . The clamp  14  then is closed, by bending of flexible portion  24 , to bring it into the arrangement shown in FIG. 3 in which it is able to encircle the post. Each clamp  14  may have a projection  60  of a respective cross-section, or more than one projection  60 , such that each clamp is engageable with only one of posts  12 , thereby ensuring lumbar support  10  is installed in the correct orientation.  
     [0033] With the clamp  14  in the arrangement shown in FIG. 3, and a fastener passed through apertures  38 ,  40  and tightened, the clamp  14  is secured on the post  12  (not shown in FIG. 3). Post  12 , as shown in FIG. 1, is of oval cross-section and clamp  14  makes contact with it at three principal locations. The first location is at flexible portion  24 . As is evident from FIG. 3, portion  24  extends across one end of the generally oval opening defined by clamp  14  and in which post  12  is secured. Each of the other two locations are at the other end of that opening. One of these other locations is defined by surface portion  54   d  of the inner surface  54  of reinforced portion  22 . The other one of these is defined by corresponding parts of the reinforced portion  20 ; that is, by the respective edge  50   a  of each side flange  50  of portion  20 .  
     [0034] As shown in FIG. 3, surface portion  54 d of reinforced portion  22  and edges  50   a  of reinforced portion  20  are mutually disposed symmetrically with respect to the oval opening defined by clamp  14  and, hence, with respect to a post secured in that opening. The surface portion  54   d  is inclined with respect to each edge  50   a  at an obtuse included angle such as from about 110° to 130°. The included angle is about 120° in the embodiment illustrated. A major plane of symmetry for the oval opening (and hence for the post  12  therein) substantially bisects that angle. The arrangement is such that surface portion  54   d  is tangential to the post  12  at one of the other locations, to one side of the major plane; while each edge  50   a  is similarly tangential to the post  12 , but at the other side of the major plane.  
     [0035] With post  12  secured in clamp  14 , the three principal locations of contact between the clamp and post most preferably are such that, with tightening of a fastener through apertures  38 ,  40 , surfaces  34 ,  36  are slightly spaced. The spacing preferably is about 4 or 5 mm. However, the arrangement is such that this range can be increased such as up to 8 mm or decreased down to zero spacing between surfaces  34 ,  36 . In the overall range of 0 to 8 mm, the three locations of principal contact with post  12  are maintained, although the locations of the tangential contact with post  12  vary slightly with variation in that range. As will be appreciated, variation in the range enables accommodation of over- or under-side posts within specified tolerances.  
     [0036] Clamp  14  makes secondary clamping contact with the post  12 . The location of the contacts is along the ridges  56  and  57 , and each ridge of the series  58  and  59 .  
     [0037] In the arrangement of FIG. 4, each part corresponding to a part of the arrangement of FIG. 1 has the same reference numeral, plus  100 . Thus, the lumbar support  110  is of the flexible band type which includes a band  116  and, at each end of band  116 , a respective clamp  114 . However, FIG. 4 shows only one end portion of band  116  and, hence, only  114  is shown. Similarly, only one post  112 , of a pair of side posts of a seat backrest frame, is shown.  
     [0038] In this instance, the support  110  includes an adjustment mechanism, with this comprising an electric motor  70  and a drive spindle  72  coupled to the output shaft (not shown) of motor  70  by gearing (also not shown). Motor  70  is mounted on band  116 , adjacent to the one clamp  114  and post  112  shown, with its drive shaft extending transversely of band  116 . Spindle  72  extends from motor  70 , away from the one clamp  114  and parallel to band  116 . The band  116  has two portions  116   a  and  116   b  which overlaps longitudinally and are inter-fitted to enable variation in the extent of their overlap. Motor  70  is mounted on portion  116   a , while the end of spindle  72  remote from motor  70  is in threaded engagement with a boss (not shown) on portion  116   b . Thus, by operating motor to rotate spindle  72  in a required direction, band  116  can be shortened or lengthened whereby, with support  110  clamped at each end to a respective post  112 , the curvature of band  116  and hence the degree of lumbar support can be varied.  
     [0039] With one exception, clamp  114  and band  116  are similar to those of support  10  of FIG. 1, although clamp  114  is shown in a simplified form. That exception is in the provision of a stiff bracket  74  on the one clamp  114  shown (although a similar bracket most preferably would be provided on the clamp  114  at the other end of band  116 ). The bracket  74  is shown as mounted on the end of the same extension section as band  116  extends from, in this case section  130  (in line with the arrangement of FIG. 1). While this arrangement is preferred, it is not necessary as bracket  74  could be mounted on the end of extension section  132 .  
     [0040] The bracket  74  extends from clamp  114  such that, with clamp  114  secured on its post  112  as required for correct positioning of band  116  in relation to a seat backrest frame, bracket  74  projects forwardly with respect to the backrest frame to facilitate provision of side bolster support for a covered and padded backrest. Thus the bracket  74  extends laterally with respect to the longitudinal extent of the passage defined by clamp  114 , when closed, and through which post  112  extends. The bracket  74  preferably is inclined slightly outwardly and forwardly, so as to enable a person to position his or her torso comfortably between opposed bolster supports.  
     [0041] As shown, the frame  74  preferably is formed from a length of stiff wire. It has a U-shaped form providing substantially parallel legs  75 ,  76  and a web portion  77  which extends between a respective end of each leg  75 ,  76 . The other end of each leg  75 ,  76  extends along, and is secured in a boss or clip  78  formed integrally with, a respective one of the side flanges  150  of the extension section  130 . From each boss or clip  78 , each leg projects substantially directly forwardly, that is, substantially perpendicularly to a plane parallel to the backrest frame. However, outwardly from the bracket  114  on which it is mounted, each leg is bent to provide the slight outward inclination of bracket  74 .  
     [0042] In use of the lumbar support  110 , its bracket  74  (as with the backrest frame on which support  110  is mounted) would be covered with padding. The padding then would be contained within an outer covering for the backrest frame which, in addition to conforming to the backrest frame, would conform to and accommodate therein the bracket  74  and its padding.  
     [0043] A clamp as above described for fixing a lumbar support to a seat backrest frame is particularly advantageous as it is relatively cheap to manufacture, being an integral structure formed by moulding. It is also easy to install, for example by an automated process, due to the engageable parts including complementary means for locating and aligning those parts, particularly the apertures through which a fastener is passed. Furthermore, the clamp ensures a firm attachment for the lumbar support which is assisted by the inherent resiliency of the material of the clamp in addition to the above described features such as the complementary shape of the concave sections and transverse ridges thereon.  
     [0044] The invention described herein is susceptible to variations, modifications and/or additions other than those specifically described and it is to be understood that the invention includes all such variations, modifications and/or additions which fall within the spirit and scope of the above description.