Abstract:
A method for standardizing fastener installation for a golf car suspension system includes configuring each of a plurality of suspension system component connections as a metal-to-metal contact connection. The method further includes selecting a single fastener engagement size for each of a plurality of fasteners used to couple the component connections. Further, the method includes applying a predetermined torque to the plurality of fasteners, the predetermined torque selected from a predetermined range of torque values. Still further, the method includes installing each of the fasteners using a single installation tool.

Description:
FIELD  
       [0001]     The present disclosure relates to methods for connecting suspension and drive train elements for golf car and off-road utility vehicles.  
       BACKGROUND  
       [0002]     The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.  
         [0003]     Golf cars and many off-road or utility vehicles, hereinafter “golf cars” commonly have suspension systems requiring multiple components and multiple fasteners for installation. Assembly line construction of golf cars commonly requires multiple installation tools and multiple different supplies of fasteners be present. This can lead to installation of incorrectly sized fasteners or application of insufficient or excessive torque to the fasteners if the wrong fastener or incorrect torque tool is used.  
         [0004]     Assembly costs of common golf car designs are therefore limited in part by the quantity of fastener types and torques to be used. Further, visual inspection is often unable to determine if incorrect fasteners or torques are used, leading to potential deficiencies. Use of installation dollies or fixtures to hold components during assembly is also potentially limited due to different access requirements for different sized installation tools.  
       SUMMARY  
       [0005]     According to several embodiments of the present disclosure, a method for standardizing fastener installation for a golf car suspension system includes configuring each of a plurality of suspension system component connections as a metal-to-metal contact connection. The method further includes selecting a single fastener engagement size for each of a plurality of fasteners used to couple the component connections. Further, the method includes applying a predetermined torque to the plurality of fasteners, the predetermined torque selected from a predetermined range of torque values. Still further, the method includes installing each of the fasteners using a single installation tool.  
         [0006]     According to other embodiments, a method for standardizing fastener installation for a golf car suspension system, the suspension system including a leaf spring and a shock absorber includes configuring each of a plurality of suspension system component connections as one of a plurality of metal-to-metal contact connections. The method also includes selecting a single fastener engagement size for each of a plurality of fasteners used to couple the plurality of component connections. The method further includes sub-assembling the plurality of suspension system component connections prior to torquing any of the plurality of fasteners. The method still further includes applying a single predetermined torque value to each of the plurality of fasteners, the predetermined torque value selected from a range of torque values.  
         [0007]     According to still other embodiments, a method for assembling a golf car suspension system, the suspension system having a shoulder bolt having a bolt head, a bolt having a bolt shaft, a leaf spring having a rolled end, a leaf spring link assembly, a shock absorber having a connecting sleeve and an extension sleeve positioned within the connecting sleeve, and a support plate includes installing a plurality of fasteners to operably assemble the golf car suspension system. The method also includes sliding a first fastener defining the shoulder bolt having a starting thread position through the rolled end of the leaf spring. The method further includes connecting a second fastener defining a first nut into engagement with the starting thread position to operably define a first metal-to-metal contact connection. The method still further includes positioning a third fastener defining the bolt with the bolt shaft inserted through the extension sleeve until a bolt engagement face of the bolt contacts a first end of the extension sleeve. The method yet still further includes engaging a second end of the extension sleeve with a frame member to operably create a second metal-to-metal contact connection. The method thereafter includes applying a torque having a single torque value to each of the plurality of fasteners.  
         [0008]     Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.  
     
    
     DRAWINGS  
       [0009]     The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.  
         [0010]      FIG. 1  is a perspective view of a golf car having the rear suspension assembly according to various embodiments of the present disclosure;  
         [0011]      FIG. 2  is a bottom plan view of the golf car of  FIG. 1 ;  
         [0012]      FIG. 3  is a perspective view of an assembly including a rear suspension assembly of the present disclosure;  
         [0013]      FIG. 4  is a bottom plan view of the assembly of  FIG. 3 ;  
         [0014]      FIG. 5  is a partial cross sectional view taken at section  5 - 5  of  FIG. 3 ; and  
         [0015]      FIG. 6  is a cross sectional view taken at section  6 - 6  of  FIG. 3 . 
     
    
     DETAILED DESCRIPTION  
       [0016]     The following description is merely exemplary in nature and is in no way intended to limit the present disclosure, application, or uses. Throughout this specification, like reference numerals will be used to refer to like elements. As referred to herein, the term “golf car” is synonymously used to describe application of the present disclosure to golf cars as well as sport utility vehicles such as modified golf cars, used for example as food and/or beverage cars, golf cars adapted for use as hunting/sporting clays vehicles, golf course maintenance vehicles, and the like.  
         [0017]     Referring generally to  FIG. 1 , a golf car  10  can include a body  12  supported from a structural frame  14 . Frame  14  can also support a plurality of wheels including a first steerable wheel  16  and a second steerable wheel  18 . In addition, powered or driven wheels including a first driven wheel  20  and a second driven wheel  22  are commonly connected to a rear structural portion of frame  14 . A front suspension system  23  can also be provided which is adapted for supporting each of the first and second steerable wheels  16 ,  18 . A rear suspension system  24  can also be provided which is adapted for supporting each of the first and second driven wheels  20 ,  22  from frame  14 . A steering mechanism  26  which commonly includes a steering wheel and a support post assembly is also included to provide the necessary steering input to first and second steerable wheels  16 ,  18 .  
         [0018]     Golf car  10  can also include a passenger bench seat  28  and a passenger back support cushion  30 . A cover or roof  32  can also be provided which is supported from either body  12  or frame  14  by first and second support members  34 ,  36 . A windscreen or windshield  38  can also be provided which is also supported by each of first and second support members  34 ,  36 . A rear section of roof  32  can be supported by each of a first and a second rear support element  40 ,  42 . Other items provided with golf car  10  include golf bag support equipment, accessory racks or bins, headlights, side rails, fenders, and the like.  
         [0019]     Golf car  10  is commonly propelled by a power unit such as an engine or battery/motor system which is commonly provided below and/or behind bench seat  28 . Golf car  10  is capable of motion in either of a forward direction “A” or a rearward direction “B”. Each of first and second driven wheels  20 ,  22  can be commonly supported to frame  14  using rear suspension system  24 . Each of first and second steerable wheels  16 ,  18  can be independently or commonly supported to frame  14 , therefore the present disclosure is not limited by the design of front suspension system  23 .  
         [0020]     As best seen in reference to  FIG. 2 , frame  14  can further include a longitudinally arranged first frame member  44  and a second frame member  46 . First and second frame members  44 ,  46  can be hollow, tubular shaped members created of a steel material or similar structural material and formed by welding, extruding, hydroforming, or similar processes. A first and second leaf spring  48 ,  50  support each of first and second driven wheels  20 ,  22 . A first leaf spring/shock support assembly  52  can be connected to first leaf spring  48  and first frame member  44 . Similarly, a second leaf spring/shock support assembly  54  can be connected to second leaf spring  50  and second frame member  46 . Each of first and second leaf spring/shock support assemblies  52 ,  54  are also connected to an axle housing  56  within which an axle (shown in  FIG. 5 ) is rotatably disposed for providing driving power to the first and second driven wheels  20 ,  22  through a gear train or axle gear housing  57  connected to the power unit.  
         [0021]     First and second leaf springs  48 ,  50  can be connected at a rearward facing end to first and second frame members  44 ,  46  by each of a first and second link assembly  59 ,  60 . In addition, first and second leaf springs  48 ,  50  can be connected at a forward facing end to first and second frame members  44 ,  46  by each of a first and second bracket assembly  62 ,  64 . The use of first and second leaf springs  48 ,  50  further helps reduce deflection of the rear suspension system  24  in either of a first or second deflection direction “C” or “D”.  
         [0022]     Referring now to  FIG. 3 , multiple components of the rear drive assembly  58  include axle gear housing  57  which divides axle housing  56  into each of a first housing portion  66  and a second housing portion  68 . An axle  70  extending beyond distal ends of axle housing  56  is rotatably disposed within axle housing  56 . Rotation of axle  70  by axle gear housing  57  provides the rotating drive for first and second driven wheels  20 ,  22 .  
         [0023]     According to several embodiments, rear suspension system  24  can further include a first shock absorber  72  and a second shock absorber  74 . First shock absorber  72  can include a first connecting sleeve  76  which is fastened using a fastener  78  to a first frame extension  80 . First frame extension  80  is a structural element which can be fixedly connected to first frame member  44  for example by welding. Similarly, second shock absorber  74  can include a first connecting sleeve  82  which is connected using a fastener  84  to a second frame extension  86  similar in design to first frame extension  80  but fixedly connected to second frame member  46 . For installation of both first and second connecting sleeves  76 ,  82 , a nut  88  such as a weld nut can be fixedly connected to both first and second frame extensions  80 ,  86  to engage fasteners  78  and  84 . First shock absorber  72  can further include a second connecting sleeve  90  which is connected using a fastener  92  to first connecting member  94 . Similarly, second shock absorber  74  can include a second connecting sleeve  96  connected by a fastener  98  to second connecting member  100 .  
         [0024]     First connecting member  94  can be positioned between first housing portion  66  and a first support plate  102 . First leaf spring  48  is sandwiched between first support plate  102  and first connecting member  94  using a first U-shaped bolt  104 . Similarly, second connecting member  100  can be positioned between second housing portion  68  and a second support plate  106 . Second leaf spring  50  is sandwiched between second connecting member  100 , and second support plate  106  using a second U-shaped bolt  108 .  
         [0025]     Each of the first and second leaf springs  48 ,  50  can be connected to respective ones of first and second frame members  44 ,  46  using first and second bracket assemblies  62 ,  64 . First and second bracket assemblies  62 ,  64  can be welded to fixedly connect to the first or second frame member  44 ,  46 . A first shoulder bolt fastener  110  is inserted through opposed walls of the first bracket assembly  62  and a rolled forward end  112  of first leaf spring  48 . Similarly, a second shoulder bolt fastener  114  is inserted through opposed walls of the second bracket assembly  64  and a rolled forward end  116  of second leaf spring  50 .  
         [0026]     As previously noted first and second link assemblies  59 ,  60  connect the rear portions of first and second leaf springs  48 ,  50  to first and second frame members  44 ,  46 . Each of the first and second link assemblies  59 ,  60  include a first shackle plate or first link  118  and a second shackle plate or second link  120 , both connected to a first flange member  122  outwardly fixedly connected to first and second frame members  44 ,  46  and a second flange member  124  inwardly fixedly connected to first and second frame members  44 ,  46 . A first and second shoulder bolt fastener  126 ,  128  are inserted through first link  118 , first flange member  122 , a spacing sleeve  134 , and second link  120  of each of first and second link assemblies  59 ,  60 . A third and fourth shoulder bolt fastener  130 ,  132  are inserted through first link  118 , a rolled end  136  or  138  of first or second leaf springs  48 ,  50 , and through second link  120 . A plurality of washers/bushings  140  made of a low coefficient-of-friction polymeric material such as a polyamide material can be inserted between first or second links  118 ,  120  and first or second flange members  124 , between first or second flange members  124  and spacing sleeves  134 , or between first or second links  118 ,  120  and rolled ends  136 ,  138  to reduce friction at these locations. A nut  142  such as a weld nut, standard nut, or friction nut can be used for installation of the various shoulder bolts. For consistency, nuts used for the present disclosure are hereinafter referred to as weld nuts.  
         [0027]     Shoulder bolts are used for shoulder bolt fasteners  110 ,  114 , first and second shoulder bolt fasteners  126 ,  128 , and third and fourth shoulder bolt fasteners  130 ,  132  for several reasons. Shoulder bolts define a pre-determined length of bolt shaft before the start of a thread end. The pre-determined length of bolt shaft fixes a spacing width of first and second bracket assemblies  62 ,  64  and first and second link assemblies  59 ,  60 . The start of the thread end also defines a metal-to-metal contact connection between a nut used at the ends of these fasteners and the bolt shaft when connecting the nut to the appropriate first or second flange member  122 ,  124  or first or second link  118 ,  120 . In several embodiments, an installation torque range of approximately 20 to 25 lb-ft (27.12 to 33.89 Nm) can be applied to the shoulder bolt fasteners while preventing the crushing of polymeric washers/bushings  140 .  
         [0028]     First and second leaf springs  48 ,  50  help limit the vertical deflection of axle housing  56 . First and second shock absorbers  72 ,  74  dampen the vertical travel of axle housing  56  and provide a positive stop for the vertical travel. First and second connecting members  94 ,  100 , function in part to provide an engagement area for first or second leaf springs  48 ,  50  to contact axle housing  56 , and to provide for connection of first and second shock absorbers  72 ,  74 .  
         [0029]     Referring now generally to  FIG. 4 , it will be evident that axle gear housing  57  can be positioned closer to or further from any one of the first or second leaf springs  48 ,  50 . This affects the individual lengths of first or second housing portions  66 ,  68 . Weld nut  142  is applied to shoulder bolt fastener  110  to couple first bracket assembly  62  to first frame member  44 . A weld nut  144  is similarly applied to shoulder bolt fastener  114  to couple second bracket assembly  64  to second frame member  46 . First U-shaped bolt  104  is fastened to first support plate  102  using a first and second nut  146 ,  148 . Similarly, second U-shaped bolt  108  is fastened to second support plate  106  using a third and fourth nut  150 ,  152 . Each of the first, second, third, and fourth nuts  146 ,  148 ,  150 , and  152  create a metal-to-metal contact connection with the respective first or second support plate  102 ,  106 . In several embodiments, these metal-to-metal contact connections permit installation of first, second, third, and fourth nuts  146 ,  148 ,  150 , and  152  using an installation torque ranging from 20 to 25 lb-ft (27.12 to 33.89 Nm) inclusive. In several embodiments, a pin  154  is connected to both first and second leaf springs  48 ,  50  and extends through an aperture created in each of first and second support plates (toward the viewer as viewed in  FIG. 4 ). Installation of pin  154  in the aperture fixes the orientation of rear suspension system  24  relative to frame  14 . In other embodiments (not shown), pin  154  is fixed on first and second support plates  102 ,  106  and the corresponding aperture is disposed in first and second leaf springs  48 ,  50 .  
         [0030]     Referring now to  FIG. 5 , an exemplary installation of first connecting sleeve  76  of first shock absorber  72  to first frame extension  80  is shown. Installation of first connecting sleeve  82  of second shock absorber  74  to second frame extension  86 , and both second connecting sleeves  90  and  96  of first and second shock absorbers  72 ,  74  to first and second connecting members  94 ,  100 , are similar and will therefore not be further discussed. Fastener  78  such as a bolt includes a shaft  155  and an engagement face  156 . Shaft  155  is inserted through a through-bore of an extension sleeve  158 , and through an aperture of first frame extension  80 . Shaft  155  also has a threaded end  159  which is threadably engaged by a receiving nut  160  which can be welded or otherwise fixedly connected to first frame extension  80 . A fastener head  161  can be configured for example in a hexagonal or similar geometric shape or provided with a similarly shaped female key receiving slot as known. A length “E” of extension sleeve  158  is predetermined to create clearance for first connecting sleeve  76  and to define a metal-to-metal contact connection between engagement face  156 , extension sleeve  158 , and first frame extension  80 . This metal-to-metal contact connection prevents first connecting sleeve  76  from being frictionally or non-rotationally bound between engagement face  156  and first frame extension  80 . A length of first connecting sleeve  76  is less than length “E” therefore free rotation of first connecting sleeve  76  about extension sleeve  158  is permitted. Because of the metal-to-metal contact connections provided at first and second ends  157 ,  157 ′ of extension sleeve  158 , fastener  78  can be torqued to a torque value ranging between and inclusive of 20 to 25 lb-ft (27.12 to 33.89 Nm).  
         [0031]     Referring now to  FIG. 6 , an exemplary installation of first link assembly  59  is shown. Installation of second link assembly  60  is substantially identical, and will therefore not be further discussed herein. Third shoulder bolt fastener  130  includes a head engagement face  162  and a shaft  163 . Head engagement face  162  contacts first link  118  when shaft  163  is disposed through an aperture of first link  118 , an aperture of a first washer/bushing  140 ′, a through-aperture of rolled end  136  of first leaf spring  48 , an aperture of a second washer/bushing  140 ″, an aperture of second link  120 , and is threadably received by a weld nut  164  similar to weld nut  142 . A threaded end  165  of shaft  163  is defined from a starting thread position  166 . A fastener head  168  can be configured for example in a hexagonal or similar geometric shape or provided with a similarly shaped female key receiving slot. Starting thread position  166  in contact with weld nut  164 , which is also in contact with second link  120 , define a metal-to-metal contact position or connection between second link  120 , nut  164  and shaft  163  when head engagement face  162  contacts first link  118 . A shaft length “F” is therefore predetermined based on a width “G” of rolled end  136  of first leaf spring  48  plus a free extending thickness of both first and second washer/bushings  140 ′,  140 ″ beyond first leaf spring  48 . A metal-to-metal contact connection between nut  164  and shaft  163  will therefore occur before first or second washer/bushings  140 ′,  140 ″, which are created of a resilient polymeric material, will yield or crush. Because of the metal-to-metal contact connection provided between nut  164  and shaft  163 , third shoulder bolt fastener  130  can be torqued to a torque value ranging between and inclusive of 20 to 25 lb-ft (27.12 to 33.89 Nm).  
         [0032]     Referring back to  FIG. 3 , the installation of first and second shoulder bolt fasteners  110 ,  114  is similar to the installation described in reference to  FIG. 6 , having rolled ends  136 ,  138  and first and second links  118 ,  120  replaced by rolled forward ends  112 ,  116  and the walls of first and second bracket assemblies  62 ,  64 . The installation first and second shoulder bolt fasteners  126 ,  128  is also similar to the installation described in reference to  FIG. 6 , having rolled ends  136 ,  138  and first and second links  118 ,  120  replaced by spacing sleeves  134  and first and second flange members  122 ,  124  respectively.  
         [0033]     Use of a predetermined range of torque values also permits all of the components of rear suspension system  24  to be sub-assembled and/or connected to frame  14  prior to applying the desired torque. This permits a “loose assembly” of components and therefore some reorientation as necessary as the various components are added to the suspension system. Variations between suspension systems due to variations in frame geometry, part variability, installation tolerances, and the like can therefore be accommodated and wheel alignment maintained before the fasteners of the sub-assembled suspension system are torqued.  
         [0034]     Metal-to-metal contact connections are established during installation of all the fasteners of the present disclosure. A torque value selected from a predetermined torque range for all the fasteners of the present disclosure can therefore be used. In some embodiments, this torque range is between and inclusive of 20 to 25 lb-ft (27.12 to 33.89 Nm), however the disclosure is not limited to this range, and either lower or higher torque values can be used. In addition, the same engagement size for each fastener head or nut is also selected for all fasteners and nuts of the present disclosure. According to several embodiments, a 15 mm fastener head and nut size is selected, however the disclosure is not limited to this size. By using a standard torque range and common fastener head and nut engagement sizes, all the fasteners of the present disclosure can be installed with the same installation tool, reducing the possibility of installing any fastener or nut to an insufficient torque, over-torquing the fastener or nut and crushing the polymeric washers, or installing an incorrectly sized fastener or nut. Assembly time can therefore be reduced, thereby reducing assembly costs. Further, subsequent maintenance is also simplified as the mechanic does not have to change torque settings or stock multiple fastener sizes to remove or replace suspension components.  
         [0035]     The description herein is merely exemplary in nature and, thus, variations that do not depart from the gist of that which is described are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.