Abstract:
A suspension system for a wheeled conveyance includes a swing arm coupled to be pivotally mounted to a part of wheeled conveyance. The swing arm has one end thereof coupled to one end of an extensible biasing means and the other end of extensible biasing means configured to be coupled to a further part of wheeled conveyance. The other side of swing arm has a wheel mount for a wheel of wheeled conveyance. The swing arm having its pivot point between said one end and said other side of said swing arm.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a suspension system and relates particularly, though not exclusively, to a suspension system for a golf buggy. 
         [0003]    2. Description of the Relevant Art 
         [0004]    Spring suspension systems for golf buggies are known as shown in Australian Patent Application No, 2003271432. In this application a hinged scissor link is used with compression spring being compressed when travelling over undulations. The spring can be replaced by a shock absorber piston arrangement but they all suffer the same problem of “bottoming out” when there is no further compression available. There is also an unacceptable friction generated if shock absorbers replace the compression spring. 
       SUMMARY OF THE INVENTION 
       [0005]    Embodiments described herein are directed to a suspension system which overcomes these deficiencies. 
         [0006]    The embodiments described herein are further directed to a suspension system which is simple to fit and maintains correct buggy geometry. 
         [0007]    A suspension system for a wheeled conveyance includes a swing arm configured to be pivotally mounted to a part of said wheeled conveyance, said swing arm having one end thereof coupled to one end of an extensible biasing means and the other end of said extensible biasing means configured to be coupled to a further part of said wheeled conveyance, the other side of said swing aim having a wheel mount for a wheel of said wheeled conveyance and said swing arm having its pivot point between said one end and said other side of said swing arm. 
         [0008]    In some embodiments, said further part of said wheeled conveyance is above said one end of said swing arm. It is preferred that said extensible biasing means is a spring, typically a coil spring. 
         [0009]    In a practical embodiment said wheel mount is a sleeve for an axle of said wheel. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The structure and functional features of referred embodiments of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which: 
           [0011]      FIG. 1  is a front perspective view of a first embodiment of a golf buggy or cart incorporating a suspension system; 
           [0012]      FIG. 2  is a rear perspective view of the golf buggy or cart shown in  FIG. 1 ; 
           [0013]      FIG. 3  is a rear perspective view similar to  FIG. 2  but showing the attachment of the wheels to the frame of the golf buggy or cart; 
           [0014]      FIG. 4  is a similar view to that of  FIG. 3  viewed from above; 
           [0015]      FIG. 5  is a side view of the golf buggy or cart of  FIG. 1  with a golf bag attached; 
           [0016]      FIG. 6   a  is an enlarged view of the suspension system with the spring in a first position; 
           [0017]      FIG. 6   b  is a similar view to that of  FIG. 6   a  with the spring in a second position; 
           [0018]      FIG. 7  is a similar view to that of  FIG. 1  showing the golf buggy or cart moving over a non-level surface; 
           [0019]      FIG. 8   a  is a rear perspective view of a golf buggy or cart having a suspension system; 
           [0020]      FIG. 8   b  is a front perspective view of  FIG. 8   a;    
           [0021]      FIG. 9  is a similar view to that of  FIG. 8   b  at a higher viewing angle; 
           [0022]      FIG. 10   a  is a view from arrow  10   a  on  FIG. 9 ; 
           [0023]      FIG. 10   b  is a vertical cross-sectional view through the braking mechanism of the suspension system of  FIG. 10   a;    
           [0024]      FIG. 10   c  is view in the direction of arrow  10   c  in  FIG. 10   b  but having the braking mechanism shown in the braked position; 
           [0025]      FIG. 11   a  is a view in the direction of arrow  11   a  in  FIG. 9 ; and 
           [0026]      FIG. 11   b  is a similar view to thin of  FIG. 11   a  showing movement over an undulating surface. 
       
    
    
       [0027]    While the invention may be susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. The drawings may not be to scale. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but to the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention as defined by the appended claims. 
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0028]    In order to avoid duplication of description, identical reference numerals will be shown, where applicable, throughout the illustrated embodiments to indicate similar integers. 
         [0029]    In the drawings a first embodiment is shown in  FIGS. 1 to 7  in which there is shown a hand pulled golf buggy or cart  10 . The golf buggy  10 , except for the rear suspension  12 , is readily available from a sports store. Typically, buggy  10  will include a horizontal base frame  14  having a front frame element  16 , two side frame elements  18 ,  20  and a rear sleeve  22  for retaining the attachment of the rear suspension  14  thereto. An angled U-shaped frame member  24  is pivotally attached to the side frame elements  18 ,  20  to enable the golf buggy  10  to be folded away. A handle  26  is also pivotally attached to frame member  24  by a ratchet device  28  to allow the handle to be folded away for storage and allows the handle to be angularly adjusted to suit the goiter. A U-shaped support  30  is also pivotally attached to frame member  24  to cradle a golf bag  32 . A stand  34  allows contact with the ground if a sprung third wheel  36  bottoms out on the ground when a golfer sits on the seat  38 . A bag rest  41  prevents the golf bag  32  from dragging across the ground when moving the buggy  10 . The golf buggy or cart  10  completes the description of the typical golf buggy or cart. 
         [0030]    One embodiment is directed to a suspension for the rear wheels  40  of a golf buggy or cart. 
         [0031]    The wheels  40  have a large diameter and a wide tread to prevent damage to the grass of a golf course. Each wheel has a stub axle  42  which is rotatable in the hub  44  of wheel  40 . In the prior art there would be no suspension and the stub axles  42  would be inserted into the open ends of rear sleeve  22  and locked into position through respective locking screws  46  which enter sleeve  22  through threaded bosses  48 . The wheels  40  may be attached to rear sleeve  22  through a suspension system to be now described. 
         [0032]    The suspension includes a swing arm  50  which is pivotally mounted at  52  to an axle  54 . Axle  54  is configured to slide inside rear sleeve  22  and be locked into position by locking screws  46 . Axle  54  has an arm member  56  which is forwardly mounted thereon in this embodiment. It is possible to reverse this position if required. Ann member  56  has a bent arm  58  whose free end is located outwardly of the buggy  10  and is located above swing arm  50 . The free end  60  of arm  58  is coupled to one end  62  of swing arm  50  by a spring  64 . Spring  64  is typically a coil spring which is tensioned when stretched. At the other end  66  of swing arm  50  is a sleeve  68  mounted at right angles to swing arm  50 . Sleeve  68  has locking screw  70  which enters sleeve  68  through a threaded boss  72 . Wheels  40  can be secured to buggy  10  through axle  42  being inserted into sleeve  68  and being locked into position by locking screw  70 . 
         [0033]      FIGS. 6   a  and  6   b  illustrate how the tension can be adjusted for the suspension.  FIG. 6   a  shows the position of base frame  14  under load i.e. when carrying golf bag  32 , whereas the broken lines indicate the unloaded position without golf bag  32 .  FIG. 6   b  shows a similar view to that of  FIG. 6   a  but the position of arm member  56  has been rotated relative to swing arm  50  to extend spring  64 . The resulting tension will allow the same ground clearance to be retained as in  FIG. 6   a  but a heavier load can be carried by the buggy through the additional spring tension. The softness of the spring  64  can be predetermined by the type of spring used and the relative rotation as described of swing arm  50  as described above. 
         [0034]    The operation of this embodiment is clearly illustrated in  FIG. 7  where buggy  10  is shown to be travelling over undulating ground. The golf bag  32  has been removed to show the wheels  40  and the action of the suspension.  FIG. 7  shows a mound  74  over which wheel  40  must move. Wheel  40  will ride over mound  74  and cause swing arm  50  to rise up or rotate about pivot  52 . The rotation of swing arm  50  will have the opposite effect on end  62  which will rotate downwardly under the tension of spring  64 . There will be smooth transition with the buggy  10  maintaining its position relative to the ground. The other wheel  40  is shown entering a depression  76  in the ground and the reverse rotation of swing arm  50  will occur. The suspension system will provide a smooth ride over any undulations or depressions. 
         [0035]    In  FIGS. 8 to 11  a second embodiment is shown which is operationally similar to the embodiment described with reference to  FIGS. 1 to 7 . The same reference numerals have been used for similar integers to avoid duplication and repetition of description. Reference should be made to the previous embodiment when previously referenced integers are not described in this embodiment. This embodiment is suited to retro fitting an existing golf buggy with the suspension system. In this embodiment the circular tubing except for sleeves  68  has been replaced by square or rectangular tubing. Swing arm  50  has rectangular tubing and has an end tab  100  to which one end of spring  64  is attached. Arm member  56  and bent arm  58  has been replaced by a shaped angle arm member  102  which has a side arm  104  which acts like a hooded end member. The other end of spring  64  is attached to side arm  104 . A stop member  106  projects from shaped arm member  102  which limits the downward movement of wheel  40 . This embodiment has the spring  64  basically vertically disposed whereas  FIGS. 1 to 7  have spring  64  angularly disposed. The angular disposition of spring  64  in either embodiment can be varied to suit requirements. 
         [0036]    A further version of the suspension system is shown in  FIGS. 8 to 11  but specifically in  FIGS. 10   a ,  10   b  and  10   c . This version has the swing arm  50  extending beyond sleeve  68  and terminated by a square sleeve  108 . This will allow sleeve  68  to be on the opposite side of pivot  52  but not at the end of swing arm  50 . A rod  110  is slidably located within sleeve  108  and can be locked in a first position shown in  FIGS. 10   a  and  10   b  and a second position shown in  FIG. 10   c . Rod  110  is a loose fit within sleeve  108 . A handle  112  is secured to the end of rod  110  to allow the rod  110  to be moved between the first and second positions. A pair of apertures  114 ,  116  is located in the wall  118  of sleeve  108 . Rod  110  has a bore  120  into which is located a spring  122  which abuts a ball  124  at one end and the inner wall of sleeve  108  at the other end. The apertures  114 ,  16  have a diameter less than the diameter of ball  124  which allows ball  124  to protrude therethrough without escaping from rod  110 . By rotating handle  112  and simultaneously pushing or pulling handle  112  ball  124  will be forced inwards and rod  110  can be moved between the first and second positions. When handle  112  is returned to its non rotated position ball  124  will sufficiently protrude through aperture  114  or  116  to prevent rod  110  from moving. Wheel  40  may have spokes  126 . When rod  110  is in the second position shown in  FIGS. 8   a  and  10   c  then wheel  40  will not be able to rotate because rod  110  will engage with the sides of spokes  126 . This will prevent the buggy from moving or rolling away on inclined ground. 
         [0037]    The operation of the suspension system shown in  FIGS. 8 to 11  is identical to that described in  FIGS. 1 to 7  with  FIG. 11   b  showing the movement of swing arm  50  when moving over mound  74 . 
         [0038]    Although the preferred embodiments provide a useful solution the invention is not limited to the embodiments disclosed. The shape and construction of the suspension system can be varied to suit requirements. The use of an extensible spring  64  and swing arm  50  provides a smooth suspension system. 
         [0039]    The invention will be understood to embrace many further modifications as will be readily apparent to persons skilled in the art and which will be deemed to reside within the broad scope and ambit of the invention, there having been set forth herein only the broad nature of the invention and certain specific embodiments by way of example.