BACKGROUND  
         [0001]    The present invention relates to braking assemblies and more particularly relates to a braking assembly for wheel mounted manually operable carriages such as but not limited to wheel barrows and the like. The invention will be primarily described with reference to its attachment to wheel barrows but it will be appreciated by those skilled in the art that the arrangement described in each embodiment is capable of attachment to other manually operable wheel mounted carriages.  
         PRIOR ART  
         [0002]    Wheel barrows or variations thereof have been known for many years. They are particularly useful in domestic and industrial applications for carrying materials in small quantities. Conventional wheel barrows comprise a wheel mounted platform including an undercarriage located towards a leading end, ground engaging supports towards a trailing end and a receptacle for mounting on the carriage and which holds materials to be transported. The undercarriage is generally sloped downwards from rear to front. This geometry allows the receptacle to be deepest at the front so that the majority of the load will be forward. This results in the centre of gravity being disposed forward in the direction of the wheel to assist operator handling.  
           [0003]    In normal use, when a wheel barrow is operated on a horizontal surface the operator must lift then push to overcome its natural inertia. This requires some physical effort in both lifting and pushing. Due to the sloped geometry of the platform which is manifest when the barrow is at rest, the operator benefits from a mechanical advantage which is further enhanced once the undercarriage is lifted for use.  
           [0004]    This mechanical advantage imparted by the natural slope of the undercarriage, although advantageous for optimum weight distribution, is a disadvantage when an operator must control the wheel barrow on a momentum grade which throws the center of gravity further forward and increases the tendency for natural acceleration. This can, particularly when the barrow carries a heavy load, make the wheel barrow difficult to control as the requisite pushing effort required in normal level or inclined operation is converted to a pulling effort to resist the runaway tendency. The difficulties for the operator are further compounded by the traditional geometry of the gripping handles which are normally an extension of the undercarriage. When operating the barrow on a momentum grade an operator is reliant for control on hand gripping friction forces which must increase as the slope increases. In extreme circumstances relaxation of the manual gripping forces could cause loss of control and escape of the barrow possibly resulting in damage or injury to persons or property. Wheel barrows are not traditionally adapted with braking mechanisms yet there are many instances in normal day to day use where the ability to effect braking would increase operator and public safety, significantly improve operator control and reduce operator fatigue.  
         INVENTION  
         [0005]    The present invention is primarily directed to eliminating the problems described above. More particularly the invention is directed to a braking assembly for hand operated wheel mounted carriages such as, but not limited to, wheel barrows and which is capable of converting an operating force, such as an acceleration generated in the carriage by momentum into a braking force using the natural gravitational effects applied to the carriage control handles when the carriage encounters the momentum grade. In one broad form the present invention comprises;  
           [0006]    a braking assembly for a hand operated wheel mounted carriage such as a wheel barrow including an undercarriage mounted on at least one wheel and operating handles for controlling the attitude of said carriage, the braking assembly comprising: a braking mechanism capable of engagement with a wheel of said carriage to effect braking thereof, means operably linking said braking assembly to an actuating member associated with said operating handles; wherein said braking assembly moves between a non working state in which the braking mechanism is free of said at least one wheel and a working state in which the braking mechanism engages said at least one wheel to effect braking when said carriage encounters a slope.  
           [0007]    Preferably, the braking assembly is operatively responsive to the effects of gravity generated by a slope. According to a preferred embodiment, the actuating member comprises a sleeve which engages one or both said gripping handles and is adapted to slidably move relative thereto.  
           [0008]    In one broad form the present invention comprises;  
           [0009]    a braking assembly for a hand operated wheel mounted carriage, the carriage including a support structure comprising a platform for receiving and supporting a load, an undercarriage including at least one wheel; the braking assembly comprising:  
           [0010]    a control assembly for controlling said carriage and effecting braking by said braking assembly; the control assembly operably linked to a braking mechanism capable of engaging said at least one wheel of said carriage to effect braking thereof; wherein, said braking assembly moves between a non working state in which the braking mechanism is free of said at least one wheel and a working state in which the braking mechanism engages said at least one wheel to effect braking when said carriage encounters a slope. According to one embodiment the carriage comprises a wheel chair or wheel barrow.  
           [0011]    In another broad form the present invention comprises:  
           [0012]    a hand operated wheel mounted carriage, the carriage including a support structure comprising a platform for receiving and supporting a load, an undercarriage including at least one wheel; the carriage further including a braking assembly comprising:  
           [0013]    a control assembly for controlling said carriage and effecting braking by said braking assembly; the control assembly operably linked to a braking mechanism capable of engaging said at least one wheel of said carriage to effect braking thereof; wherein, said braking assembly moves between a non working state in which the braking mechanism is free of said at least one wheel and a working state in which the braking mechanism engages said at least one wheel to effect braking when said carriage encounters a slope.  
           [0014]    In another broad form the present invention comprises;  
           [0015]    a wheel barrow including a wheel mounted undercarriage and including a receptacle for carrying materials; characterised in that the wheel barrow includes a braking assembly comprising: a braking mechanism capable of engagement with a wheel of said carriage to effect braking thereof, means operably linking said braking mechanism to an actuating member associated with said operating handle; wherein said braking assembly moves between a non working state in which the braking mechanism is free of said wheel and a working state in which the braking mechanism engages the wheel to effect braking when said wheel barrow encounters a slope. According to a preferred embodiment, the braking assembly is operably responsive to the action of gravity.  
           [0016]    In its broadest form the present invention comprises:  
           [0017]    a wheel barrow including a braking assembly including a control assembly operably linked to a braking mechanism for effecting braking of said wheel barrow; wherein said braking assembly is responsive to the effects of gravity on said wheel barrow when said wheel barrow negotiates a slope. 
       
    
    
     DETAILED DESCRIPTION  
       [0018]    The present invention will now be described according to preferred but non limiting embodiments and with reference to the accompanying illustrations wherein:  
         [0019]    [0019]FIG. 1 shows an embodiment of the invention as applied to a wheel barrow with the braking mechanism in the non working state.  
         [0020]    [0020]FIG. 2 shows the embodiment of FIG. 1 with the braking mechanism in a working state.  
         [0021]    [0021]FIG. 3 shows an alternative embodiment of the invention as applied to a wheel barrow with the braking mechanism in the non working state.  
         [0022]    [0022]FIG. 4 shows the embodiment of FIG. 3 with the braking mechanism in a working state.  
         [0023]    [0023]FIG. 5 shows an alternative embodiment of the invention as applied to a wheel barrow with the braking mechanism in the non working state.  
         [0024]    [0024]FIG. 6 shows the embodiment of FIG. 5 with the braking mechanism in a working state.  
         [0025]    [0025]FIG. 7 shows an alternative embodiment of the invention as applied to a wheel barrow with the braking mechanism in the non working state.  
         [0026]    [0026]FIG. 8 shows the embodiment of FIG. 7 with the braking mechanism in a working state.  
         [0027]    [0027]FIG. 9 shows an alternative embodiment of the invention as applied to a wheel barrow  
         [0028]    [0028]FIG. 10 shows the embodiment of FIG. 9 with an alternative braking mechanism.  
         [0029]    [0029]FIG. 11 shows an alternative embodiment of the invention as applied to a wheel barrow. FIG. 12 shows the embodiment of FIG. 11 with an alternative braking mechanism.  
         [0030]    [0030]FIG. 13 shows an alternative embodiment of the invention as applied to a wheel barrow.  
         [0031]    [0031]FIG. 14 shows the embodiment of FIG. 13 with an alternative braking mechanism.  
         [0032]    [0032]FIG. 15 shows an embodiment of FIG. 14 with alternative braking mechanism;  
         [0033]    [0033]FIG. 16 shows an alternative the embodiment of the invention with an alternative braking mechanism.  
         [0034]    [0034]FIG. 17 shows the embodiment of FIG. 16 with alternative braking mechanism.  
         [0035]    [0035]FIG. 18 shows an alternative embodiment of FIG. 16 with alternative braking mechanism.  
         [0036]    [0036]FIG. 19 shows an alternative embodiment of the invention.  
         [0037]    [0037]FIG. 20 shows the embodiment of FIG. 19 with an alternative braking mechanism.  
         [0038]    [0038]FIG. 21 shows the embodiment of FIG. 19 with an alternative braking mechanism.  
         [0039]    [0039]FIG. 22 shows an alternative embodiment with braking mechanism.  
         [0040]    [0040]FIG. 23 shows an embodiment of the invention of FIG. 22 with alternative braking mechanism.  
         [0041]    [0041]FIG. 24 shows an alternative embodiment of the invention as applied to a wheel barrow  
         [0042]    [0042]FIG. 25 shows the embodiment of FIG. 24 with an alternative braking mechanism.  
         [0043]    [0043]FIG. 26 shows the embodiment of FIG. 25 with an alternative braking mechanism.  
         [0044]    [0044]FIG. 27 shows an alternative embodiment of the braking assembly with an alternative braking mechanism.  
         [0045]    [0045]FIG. 28 shows a braking assembly according to the embodiment of FIG. 27 with alternative braking assembly.  
         [0046]    [0046]FIG. 29 shows an alternative embodiment of the invention as applied to a wheel barrow wherein each handle comprises a sleeve member.  
         [0047]    [0047]FIG. 30 shows the embodiment of FIG. 29 with an alternative braking mechanism.  
         [0048]    [0048]FIG. 31 shows the embodiment of FIG. 29 with an alternative braking mechanism.  
         [0049]    [0049]FIG. 32 shows a braking assembly according to an alternative embodiment wherein the linkage between the actuating member and braking mechanism comprises a hydraulic line.  
         [0050]    [0050]FIG. 33 shows a braking assembly according to an alternative embodiment wherein the linkage between the actuating member and braking mechanism comprises a cable.  
         [0051]    [0051]FIG. 34 shows an alternative embodiment of the braking assembly including a brake disable or enable member. 
     
    
       [0052]    Referring to FIG. 1 there is shown an embodiment of the invention as applied to a wheel barrow with the braking mechanism in the non working state. Wheel barrow  1  comprises an undercarriage  3  which terminates at end  3  in handles  4 . End  5  of undercarriage  2  is supported by wheel  6 . Undercarriage  3  further includes thereon a receptacle  7  for receiving and holding articles or materials to be carried by wheel barrow  1 . Undercarriage  2  further comprises downwardly depending ground engaging supports  8  which provide static support when the wheel barrow is stationary. The aforesaid describes features of a typical wheel barrow. According to one embodiment of the invention wheel barrow  1  further is characterised in having a braking assembly  9  which includes a braking mechanism  10  operably connected to handle  4  via linkage  11 . FIG. 1 shows the braking assembly  9  in a non working state wherein braking mechanism  10  is free of wheel  6 . Braking mechanism  10  further comprises brake pad  12  which contacts wheel  6  when the braking assembly is in the working state. Braking assembly  9  is arranged such that linkage arm  11  is pivotally connected at pivot point  13  to brake mechanism  10  and via pivot points  14  and  15 .  
         [0053]    [0053]FIG. 2 shows the embodiment of FIG. 1 with the braking mechanism in a working state. The brake mechanism  10  is actuated in response to the force of gravity on the wheel barrow which causes rotation of handle  4  about pivot point  15 . When wheel barrow  1  encounters a momentum grade, the operator naturally pulls the handle  4  axially in the direction of arrow  16  thereby causing a moment about pivot  15 . This causes consequential movement of linkage  11  in the direction of arrow  17  causing braking mechanism  10  to rotate about pivot  18  thereby urging pad  12  against wheel  6 . Thus, braking is effected by resistance to the action of gravity by an operator.  
         [0054]    Referring to FIG. 3 there is shown an alternative embodiment of the invention as applied to a wheel barrow with the braking assembly in the non working state. Wheel barrow  20  comprises an undercarriage  21  which terminates at end  22  in handles  23 . End  24  of undercarriage  21  is supported by wheel  25 . Undercarriage  21  further includes thereon a receptacle  26  for receiving and holding articles or materials to be carried by wheel barrow  20  and further comprises downwardly depending ground engaging supports  27  which provide static support when the wheel barrow is stationary. The aforesaid describes features of a typical wheel barrow. According to the embodiment of the invention shown, wheel barrow  20  is further characterised in having a braking assembly  28  which includes a braking arm  29  operably connected to handle  23  via linkage  30 . FIG. 3 shows the braking assembly  28  in a non working state wherein braking pad  31  is free of wheel  25 . Brake pad  31  contacts wheel  25  when the braking assembly is in the working state. Braking assembly  28  is arranged such that braking arm  29  is supported by undercarriage at conjunction  32  and is pivotally connected at pivot point  30  to handle  23 .  
         [0055]    [0055]FIG. 4 shows the embodiment of FIG. 3 with the braking mechanism in a working state. The brake assembly  28  is actuated in response to the force of gravity on the wheel barrow which causes rotation of handle  23  about pivot point  34 .When wheel barrow  20  encounters a momentum grade the operator naturally pulls the handle  23  axially in the direction of arrow  35  thereby causing a moment about pivot  34 . This causes consequential movement of linkage arm  29  in the direction of arrow  36  causing braking pad  31  to engage wheel  25 . Thus, braking is effected by resistance to the action of gravity by an operator.  
         [0056]    Referring to FIG. 5 there is shown an alternative embodiment of the invention as applied to a wheel barrow with the braking mechanism in the non working state. Wheel barrow  40  comprises an undercarriage  41  which terminates at end  42  in handles  43 . End  44  of undercarriage  41  is supported by wheel  45  and further includes thereon a receptacle  46  for receiving and holding articles or materials to be carried by wheel barrow  40 . Undercarriage  41  further comprises downwardly depending ground engaging supports  47  which provide static support when the wheel barrow is stationary. The aforesaid again describes features of a typical wheel barrow.  
         [0057]    According to an alternative embodiment of the invention, wheel barrow  40  further is characterised in having a braking assembly  48  which includes a braking mechanism  49  operably connected to handle  43  via linkage arm  50 . FIG. 5 shows the braking assembly  48  in a non working state wherein braking mechanism  49  is free of wheel  45 . Braking mechanism  49  further comprises brake pad  51  which contacts wheel  45  when the braking assembly is in the working state. Braking assembly  48  is arranged such that linkage arm  50  is pivotally connected at pivot point  52  to brake mechanism  49  and at its other end to sleeve handle  53 .  
         [0058]    [0058]FIG. 6 shows the embodiment of FIG. 5 with the braking mechanism in a working state.  
         [0059]    The brake mechanism  49  is actuated in response to the force of gravity on the wheel barrow which causes relative movement of sleeve  53  in the direction of arrow  54 . When wheel barrow  40  encounters a momentum grade the operator naturally pulls sleeve  43  axially in the direction of arrow  54  to resist acceleration of the barrow thereby causing a moment about pivot  55  due to the movement of linkage arm  50  in the direction of arrow  56 . This urges pad  51  against wheel  45 . Thus, braking is effected by action of gravity on the wheel barrow and by resistance to the action of gravity by an operator.  
         [0060]    Referring to FIG. 7 there is shown an alternative embodiment of the invention as applied to a wheel barrow with the braking assembly in the non working state. The arrangement in FIGS. 7 and 8 is similar to that shown in FIGS. 3 and 4 and has been numbered in accordance with FIGS. 3 and 4. According to the embodiment of the invention shown wheel barrow  20  is characterised in that instead of employing pivoting handle  23  it includes sleeve  60  which is capable of sliding movement in the direction of arrow  61 . FIG. 7 shows the braking assembly  28  in a non working state wherein braking pad  31  is free of wheel  25 . Brake pad  31  contacts wheel  25  when the braking assembly is in the working state. Braking assembly  28  is arranged such that braking arm  29  is supported by undercarriage at conjunction  32 .  
         [0061]    [0061]FIG. 8 shows the embodiment of FIG. 7 with the braking mechanism in a working state. The brake assembly  28  is actuated in response to the force of gravity on the wheel barrow which causes sliding of sleeve  60  in the direction of arrow  62 . When wheel barrow  20  encounters a momentum grade the operator naturally pulls the sleeve  60  axially in the direction of arrow  62  thereby causing a consequential movement of linkage arm  29  in the direction of arrow  36  causing braking pad  31  to engage wheel  25 . Thus, braking is effected by resistance to the action of gravity by an operator. The braking assembly may be retro fitted to existing carriages.  
       ALTERNATIVE EMBODIMENTS  
       [0062]    FIGS.  9 - 34  show a range of braking assembly configurations each fitted to a schematic representation of a typical wheel barrow. Wheel barrow  70  comprises an undercarriage  71  which includes support platform  72  terminating at end  73  in handle  74 . Support platform  72  will normally terminate in two spaced apart handles. Opposite end  75  of undercarriage  71  is supported by wheel  76 . Undercarriage  71  further includes thereon a receptacle  77  for receiving and holding articles or materials to be carried by wheel barrow  70 . Undercarriage  71  further comprises downwardly depending ground engaging supports  78  which provide static support when the wheel barrow is stationary. The aforesaid describes features of a typical wheel barrow common to each of the embodiments shown in FIGS.  9 - 34 .  
         [0063]    The embodiments of FIGS.  9 - 34  will now be described with reference to alternative braking assemblies as shown.  
         [0064]    Referring to FIG. 9 there is shown an embodiment of the invention as applied to a wheel barrow. Braking assembly  80  includes a braking mechanism  81  which is anchored to support platform  71  via pivot  82  and to linkage rod  83  via pivot  84 . Braking mechanism  81  further comprises brake shoe  85  which contacts wheel  76  when the braking assembly is in the working state. Braking assembly  80  is arranged such that linkage arm  83  is pivotally connected at pivot point  84  to brake mechanism  81  and via pivot  86  to actuating member  87 . Actuating member  87  is connected to auxiliary handle  88  via pivot  89 . Handle  88  is connected via support arm  90  to handle  74  via pivots  91  and  92 . Actuating member  87  is adapted to rotate about pivot  93  on handle  74 . In operation, when braking is to be effected, handle  88  is urged in the direction of arrow  94  to counteract the effect of gravity acting on a load in receptacle  77  when wheel barrow  70  is operating on a slope. This action causes brake shoe  85  to be urged against the surface of wheel  76  as linkage rod  83  is urged in the direction of arrow  95  responsive to the action of handle  88 . In this case, actuating member  87  and support arm  90  will move in unison.  
         [0065]    [0065]FIG. 10 shows the braking assembly of FIG. 9 with alternative brake mechanism  96 . In this case linkage rod  83  traverses a path which enables pad  97  to engage wheel  76  at a central location. The remaining part of the braking assembly operates as described for the embodiment of FIG. 9.  
         [0066]    [0066]FIG. 11 shows an alternative embodiment of a braking assembly of FIG. 9 with handle  88  reversed below handle  74 . FIG. 12 shows the assembly of FIG. 11 with alternate braking mechanism  96 .  
         [0067]    [0067]FIG. 13 shows brake assembly  80  according to an alternative embodiment of the invention. In this embodiment, actuating member  87  is affixed to support platform  72  via pivot  86 . linkage rod  83  engages actuating member  87  via pivot  93  and handle  88  via pivot  89 . In this embodiment. As handle  88  is urged in the direction of arrow  94  linkage rod also travels in the same direction which causes free end  99  to rotate towards wheel  76  to effect braking.  
         [0068]    [0068]FIG. 14 shows a braking assembly similar to that of FIG. 13 except that the braking mechanism  97  is disposed forward of wheel  76 , such that as handle  88  is urged in the direction of arrow  94  brake shoe  97  engages the front extremity of wheel  76 . FIG. 15 shows a braking assembly similar to embodiment of FIG. 13 except that the braking mechanism  81  is disposed forward of and engages the front of wheel  76 .  
         [0069]    [0069]FIG. 16 discloses a similar braking assembly as shown in FIG. 13 except that handle  88  is shown in the mirror image position above support platform  71 .  
         [0070]    [0070]FIG. 17 discloses a similar braking assembly as shown in FIG. 15 except that handle  88  is shown in the mirror image position above support platform  71 .  
         [0071]    [0071]FIG. 18 discloses a similar braking assembly as shown in FIG. 14 except that handle  88  is shown in the mirror image position above support platform  71 .  
         [0072]    [0072]FIG. 19 shows a brake assembly according to an alternative embodiment. The assembly  100  comprises a linkage rod  101  connected at a first end to a braking mechanism  102  which comprises a pivot connection  103  which engages linkage rod  101  and pivot anchorage  112 . Free end  104  of braking arm  105  engages wheel  76  when rod  101  is urged in the direction of arrow  95 . Opposite end of rod  101  is connected to an actuating member  106  via pivot  107 . Actuating member  106  terminates in handle  108 . Actuating member  106  is connected at its opposite end via pivot  109  to bracket  110  which itself is connected to platform  72 . As handle  108  is urged in the general direction of arrow  111  this urges linkage rod  101  in the direction of arrow  95  which in turn activates braking mechanism  102 . As linkage rod  101  is urged in the direction of arrow  95  braking arm is caused to pivot about pivot  103  whereupon free end  104  is urged into contact with wheel  76  with the degree of contact dictated by gravitational effects on wheel barrow  70 . FIG. 20 shows a further embodiment of a braking assembly  100  with an alternative braking mechanism  113 , comprising anchorage  114  and braking arm  115  which is connected to linkage rod  101  via pivot  116 .  
         [0073]    [0073]FIG. 21 shows an alternative embodiment of the braking assembly  100  with alternative braking mechanism  117 , which includes brake shoe  118 . When handle  108  is urged in the direction of arrow  111 , brake shoe  118  is urged against the front of wheel  76  with the amount of braking governed by the gravitational effects acting on the wheel barrow  70 .  
         [0074]    [0074]FIG. 22 shows a variation of the general arrangement shown in FIG. 21 with an alternative braking mechanism  119 . The embodiment shows handle  108  linked to linkage rod  101  via pivot  120 . Actuating arm  106  is supported at bracket  110  at connection  121  abbreviated to clear the operating region of rod  101 . When handle  108  is urged in the direction of arrow  111  this causes rod  101  to advance in the direction of arrow  95 , thereby urging shoe  122  onto the surface of wheel  76 .  
         [0075]    [0075]FIG. 23 shows a variation of the embodiment of FIG. 22 with alternative braking mechanism  123 . Braking mechanism  123  comprises braking arm  124  which is anchored to platform  72  via connector  125  and joined to linkage rod  101  via pivot  126 .  
         [0076]    [0076]FIG. 24 is a variation of the arrangement of FIG. 19 with the handle  108  in mirror image disposition about handle  74 . The mechanics of the braking assembly  100  are otherwise identical to that described for FIG. 19. FIG. 25 is a variation of the arrangement of FIG. 20 with the handle  108  mirror image disposition about handle  74 .  
         [0077]    The mechanics of the braking assembly  113  are otherwise identical to that described for FIG. 20.  
         [0078]    [0078]FIG. 26 is a variation of the arrangement of FIG. 21 with the handle  108  in mirror image disposition. The mechanics of the braking assembly  117  are otherwise identical to that described for FIG. 21. FIG. 27 is a variation of the arrangement of FIG. 22 with the handle  108  in mirror image disposition. The mechanics of the braking assembly  119  are otherwise identical to that described for FIG. 22. FIG. 28 is a variation of the arrangement of FIG. 23 with the handle  108  in mirror image disposition. The mechanics of the braking assembly  123  are otherwise identical to that described for FIG. 23. FIG. 29 shows an alternative braking assembly  127  incorporating braking mechanism  128 . The brake mechanism  128  includes braking arm  129  which is attached at one end to platform  72  via anchorage  130 . Arm  129  engages rod  101  via pivot  131 . Rod  101  is attached to sleeve  132  which is adapted to slide relative to handle  74 . Sleeve  132  slides relative to handle  74  under the action of gravity on the wheel barrow which causes relative movement of sleeve  132  in the direction of arrow  134 . When wheel barrow  70  encounters a momentum grade the operator naturally pulls sleeve  132  axially in the direction of arrow  134  to resist acceleration of the barrow thereby causing a moment about anchorage  130  due to the movement of linkage arm  101  in the direction of arrow  95 . This urges free end  133  of arm  129  against wheel  76 . Thus, braking is effected by resistance to the action of gravity by an operator.  
         [0079]    [0079]FIG. 30 shows a brake assembly  127  similar to that shown in FIG. 29 with an alternative braking mechanism  135 . Braking mechanism  135  includes braking arm  137  which is attached at one end via anchorage  138 . Arm  137  is also attached to linkage rod  101  via pivot  138 . Thus, braking is effected by resistance to the action of gravity by an operator.  
         [0080]    [0080]FIG. 31 shows a brake assembly  139  similar to that shown in FIG. 29 with an alternative braking mechanism  140 . Braking mechanism  140  includes brake shoe  141  which is attached to rod  101 .  
         [0081]    [0081]FIG. 32 shows a braking assembly  142  according to an alternative embodiment of the invention. The assembly shown comprises a braking mechanism  143  and handle assembly  144 . Braking mechanism  143  comprises a braking arm  146  which is pivotally connected to platform  72  at anchorage  145 . Braking arm  146  is connected to hydraulic slave cylinder  147  which is operably connected to hydraulic line  148 . Hydraulic line  148  is connected to master cylinder  149  which is connected to handle  150 . movement of handle  150  in the direction of arrow  151  causes slave hydraulic cylinder  147  to urge free end  152  of braking arm  146  against wheel  76  thereby effecting braking. As for the previous embodiments described, when wheel barrow  70  is subject to gravitational effects induced by an incline a counteracting force induced by handle  150  urged in the direction of arrow  151  urges free end  152  against wheel  76 .  
         [0082]    [0082]FIG. 33 shows a further embodiment of the invention with alternative braking assembly  153 , comprising braking mechanism  154  and handle assembly  155 . Braking mechanism  154  includes braking arm  156  mounted on platform  72  at anchorage  157 . Braking arm  156  engages cable  158  which is linked at its other end to handle assembly  155 . When handle  161  is urged in the direction of arrow  160  cable  158  urges free end  162  of braking arm  156  in the direction of wheel  76  to thereby effect braking of wheel barrow  70 .  
         [0083]    [0083]FIG. 34 shows an alternative embodiment of a braking assembly. Braking Assembly  163  includes a braking mechanism  164  and a handle assembly  165 . Braking assembly  163  includes braking arm  166  which is attached to platform  72  at pivot  167 . Arm  166  is attached at pivot  168  to linkage rod  169 . Handle assembly  165  includes an actuating arm  170  which is attached to platform  72  at pivot  171 . Handle  172  is joined to disable/enable strut  173  which when engaged resists unwanted forward or reverse movement of handle  172  in the directions of either arrows  174  or  175 . When engaged, strut  173  locks the handle assembly  165  and particularly handle  172  in the directions of arrows  174  and  175  to prevent unwanted relative movement between handle  172  and platform  72 . This ensures positive control over wheel barrow  70  in circumstances when braking is required and not required. When wheel barrow  70  encounters a momentum grade the operator may release strut  173  via lever  176  to activate natural braking by braking assembly  163 . Each of the embodiments described above may include a release mechanism which activates or de activates a braking assembly.  
         [0084]    According to one embodiment braking arm  166  may comprise a flat plate which opposes the wheel tread and engages the tread to effect braking.  
         [0085]    The above described braking assemblies may be retro fitted to existing carriages and wheel barrows.  
         [0086]    It will be recognised by persons skilled in the art that numerous variations and modifications may be made to the invention as broadly described herein without departing from the overall spirit and scope of the invention.
A vehicle, such as a wheelbarrow ( 1) brakes automatically when it runs downhill. A rearward pulling force, naturally applied to handles ( 4) of barrow ( 1) by a user when resisting acceleration of barrow ( 1) down a slope, results in rearward pivoting of, or rearward movement of sleeves on, the handles ( 4). Such movements are transmitted by linkage ( 11) (or by cable or hydraulically), to braking mechanism ( 10) acting on wheel ( 6).