Patent Publication Number: US-2005126853-A1

Title: Mobile scaffolding brake

Description:
RELATED APPLICATION  
      This is a continuation of application Ser. No. 10/271,634 filed Oct. 15, 2002, which is hereby incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates generally to mobile scaffolding. More specifically, the present invention concerns a mobile scaffolding brake that can be activated from the support platform and when activated restrains motion of the scaffolding. The inventive brake enables a worker supported on the scaffolding platform to selectively prevent unsafe and inadvertent motion of the scaffolding while the worker is supported thereon.  
      2. Discussion of Prior Art  
      It is known in the art to utilize scaffolding to provide an elevated work platform to elevate a worker above a floor or ground surface to complete a task (e.g., painting, drywall finishing, etc.). The scaffolding utilized to provide the elevated work platform is often mobile scaffolding that can be quickly and easily moved from one working position to the next. For example, it is known in the art to support a scaffolding frame with one or more casters that enable the assembled scaffolding to be rolled along the floor or ground surface between working positions. However, it is desirable to prevent the scaffolding from moving when one or more workers are supported thereon.  
      It is known in the art to provide a scaffolding caster with a brake for selectively preventing the scaffolding from moving. These prior art caster brakes utilize a brake stop that engages the caster wheel and thereby prevents rotation of the wheel. These prior art caster brakes typically include a two-piece housing, with the wheel supported by one of the housing pieces and the brake stop supported by the other. The housing pieces are pivotal relative to one another so that the wheel can be pivoted into contact with the brake stop. One of the housing pieces serves as a foot-activated handle for selectively causing the wheel to be pivoted into engagement with the brake stop. In this manner, the weight of the scaffolding supported by the caster works to maintain the locking engagement between the wheel and the stop.  
      These prior art caster brakes are problematic and have several undesirable limitations. For example, the prior art brakes cannot be activated by a worker while the worker is supported on the scaffolding platform. It has been determined that in some applications it is desirable for a worker supported on the platform to manually reposition the scaffolding while supported thereon. For example, when using a mobile scaffolding to install ceiling tile (e.g., acoustical tile, etc.), OSHA regulations permit the worker supported on the scaffolding to reposition the scaffolding by pulling it along under the working edge in certain situations. The prior art caster brakes undesirably require the worker to either repeatedly climb up and down the scaffolding to set and unset the brake or require two workers (e.g., one to do the tile work on the platform and one to operate the brake from the ground) to perform the same amount of work a single worker could otherwise accomplish in the same span of time. It has further been determined that unsafe working conditions arise when a worker is supported on the scaffolding platform and the brake is not in a locked position (e.g., if the tile worker previously described fails to set the brake each time) thereby enabling the scaffolding to roll undesirably placing the supported worker in peril of losing balance and/or falling off the scaffolding. The supported worker is at the mercy of other coworkers in the area either setting the brake or refraining from intentionally or unintentionally moving the scaffolding.  
     SUMMARY OF THE INVENTION  
      The present invention provides an improved scaffolding brake that does not suffer from the problems and limitations of the prior art brakes detailed above. The inventive brake enables a worker supported on the scaffolding platform to selectively activate the brake while supported on the support platform to restrain motion of the scaffolding and thereby prevent unsafe and inadvertent motion of the scaffolding while the worker is supported thereon.  
      A first aspect of the present invention concerns a mobile scaffolding for elevating a worker above the ground. The scaffolding broadly includes a frame, a wheel, a platform, and a brake assembly. The frame is vertically elongated between a first end and a second end. The wheel is coupled to the frame adjacent the first end and is operable to rollably support the frame on the ground. The platform is horizontally supported on the frame and is operable to support the worker above the ground. The platform is vertically spaced from the wheel. The brake assembly is associated with the wheel and includes a brake pad and an actuator in communication with the pad. The brake pad is shiftable relative to the wheel into and out of a braking position wherein the wheel is generally prevented from rolling. The actuator is selectively controllable by the worker when the worker is supported on the platform to cause the brake pad to shift into and out of the braking position.  
      A second aspect of the present invention concerns a brake assembly for use with a mobile scaffolding wherein the scaffolding includes a support surface for supporting a worker elevated above the ground. The brake assembly broadly includes a housing adapted to be coupled to the scaffolding, a handle pivotally coupled to the housing, a brake stop shiftable relative to the housing into and out of a braking position wherein at least a portion of the stop is configured to engage the ground, and an elongated plunger slidable relative to the housing and presenting a first end coupled to the handle and a second end coupled to the brake stop.  
      A third aspect of the present invention concerns a method of braking a mobile scaffolding broadly including the steps of moving the scaffolding into a working position, positioning a worker on a platform on the scaffolding, and activating a brake from the platform.  
      A fourth aspect of the present invention concerns a brake assembly for use with a mobile scaffolding wherein the scaffolding includes a support surface for supporting a worker elevated above the ground. The brake assembly broadly includes a housing adapted to be coupled to the scaffolding, a manual handle pivotally coupled to the housing, a brake stop shiftable relative to the housing into and out of a braking position wherein at least a portion of the stop is configured to prevent the scaffolding from moving when the housing is coupled to the scaffolding, and an elongated coupling operably interconnecting the handle and the brake stop so that the brake stop is remotely controllable into and out of the braking position.  
      Other aspects and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments and the accompanying drawing figures.  
    
    
     BRIEF DESCRIPTION OF THE DRAWING FIGURES  
      Preferred embodiments of the invention are described in detail below with reference to the attached drawing figures, wherein:  
       FIG. 1  is a perspective view of a mobile scaffolding constructed in accordance with a preferred embodiment of the present invention and including a brake assembly associated with each of the four casters;  
       FIG. 2  is a fragmentary side elevational view of the scaffolding shown in  FIG. 1  illustrating the components of one of the brake assemblies in the release position;  
       FIG. 3  is a fragmentary enlarged side elevational view of the scaffolding shown in  FIG. 2  with portions of the brake stop shown in section and illustrating the brake assembly in the release position;  
       FIG. 4  is a fragmentary enlarged side elevational view of the scaffolding similar to  FIG. 3  with the brake assembly shown in the braking position;  
       FIG. 5  is a fragmentary enlarged side elevational view of the scaffolding taken substantially along line  5 - 5  of  FIG. 2  with the handle subassembly pivoted to the release position;  
       FIG. 6  is a fragmentary enlarged side elevational view of the scaffolding similar to  FIG. 5  with the handle subassembly shown between the release and braking positions; and  
       FIG. 7  is a fragmentary enlarged side elevational view of the scaffolding similar to  FIG. 6  with the handle subassembly shown in the braking position. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       FIG. 1  illustrates a mobile scaffolding  10  constructed in accordance with a preferred embodiment of the present invention and configured for elevating a worker (not shown) above a floor or ground surface S (see  FIGS. 2-4 ). The illustrated scaffolding  10  utilizes a pair of rollable ladder-type frames to support a vertically-adjustable platform therebetween. However, the principles of the present invention are not limited to this scaffolding configuration and equally apply to virtually any type of scaffolding so long as the scaffolding supports an elevated worker and is movable (e.g., rollable, etc.). The illustrated scaffolding  10  broadly includes a pair of frames  12  and  14 , a platform  16  supported by the frames  12 , 14 , a pair of casters  18 ,  20  and  22 ,  24  rollably supporting a respective one of the frames  12 , 14 , and a brake assembly  26 ,  28 ,  30 , and  32  associated with a corresponding one of the casters  18 , 20 , 22 , 24 , respectively.  
      In more detail, each of the frames  12 , 14  is configured to elevate the platform  16  vertically above the floor or ground surface S and support the platform  16  once elevated. The frames  12 , 14  are virtually identically configured, therefore, only the frame  12  will be described in detail with the understanding that the frame  14  is similarly constructed. The frame  12  includes a pair of spaced apart vertically extending support posts  34  and  36 . Each of the posts  34 , 36  are generally tubular in configuration presenting a hollow, generally square shaped cross section. For purposes that will subsequently be described, a plurality of spaced apertures  38  are formed in each of the posts  34 , 36  and extend through the respective post  34 , 36  to form an axially aligned pin-receiving passageway. As will subsequently be described, the lower ends of each of the posts  34 , 36  are open and configured to receive various attachment components, such as one of the casters  18 , 20 , 22 , 24 . Formed in the upper end of each of the posts  34 , 36  is a corresponding coupling shaft  40  and  42 , respectively. Each of the shafts  40 , 42  is configured to removably receive various attachment components, such as guard rails, another frame member, etc. Fixed to each of the posts  34 , 36  and extending horizontally therebetween, are a plurality of rung members  44 ,  46 ,  48 ,  50 , and  52 . The rungs  44 , 46 , 48 , 50 , 52  are spaced from one another and configured to enable the worker to climb up and down the rungs (e.g., in order to reach and exit the platform  16 ). The frame  12  defines a first, lower end  54  adjacent the rung  44  and a second, upper end  56  adjacent the rung  52  (see  FIGS. 1-2 ).  
      One exemplary frame is disclosed in pending application for U.S. patent Ser. No. 09/766,334, filed Jan. 19, 2001, entitled UTILITY SCAFFOLDING HAVING SAFETY FEATURES (sharing a common inventor with the present application and hereinafter “the Wyse &#39;334 application”), which is hereby incorporated by reference herein as is necessary for a full and complete understanding of the present invention. However, the frame could be variously constructed and configured. For example, the frame need not utilize a tubular construction and need not be a ladder-type frame.  
      The platform  16  is supported horizontally between the frames  12  and  14  and is vertically adjustable between the upper and lower ends of the frames  12 , 14 . Particularly, the platform  16  includes a pair of horizontally extending side rails  58  and  60  that support a generally flat work surface  62 . The illustrated work surface  62  is removably coupled to the rails  58 , 60  by a plurality of transverse pins  64 . Although not shown, the platform  16  preferably includes rail pins and platform clips that can be pivoted into a locking position once the surface  62  is placed on the rails  58 , 60  to prevent the surface  62  from dislodging from the pins  64 . Exemplary rail pins and clips are disclosed in the Wyse &#39; 334  application, previously incorporated herein by reference. The illustrated platform  16  further includes a pair of bracket assemblies  66 ,  68  and  70 ,  72  associated with each of the frames  12 , 14 , respectively. The paired bracket assemblies  66 , 68  and  70 , 72  include assemblies that are mirror images of each other, but otherwise each of the assemblies  66 , 68 , 70 , 72  are virtually identically configured and therefore only the bracket assembly  66  will be described in detail with the understanding that the assemblies  68 , 70 , 72  are similarly constructed. The bracket assembly  66  includes a sleeve  74  slidably received on the post  34  of the frame  12 . The sleeve  74  is generally C-shaped in cross section to define an open side configured to clear the rungs  44 , 46 , 48 , 50 , 52  as the sleeve slides relative to the frame  12 . The sleeve  74  includes a plurality of apertures formed on the inside surface that are complementally spaced to match the spacing of the apertures  38  formed in the post  34  (not shown on the assembly  66 , but see the bracket assembly  70 ). In this manner, the sleeve apertures are operable to axially align with the post apertures  38 . In this regard, the bracket assembly  66  further includes a G-shaped pin  76  that is slidably received in the axially aligned apertures to retain the platform  16  in a selected vertical position relative to the frame  12 . The G-shaped pin  76  preferably slides in a pin guide  78  and is biased into the aligned holes by a spring (not shown). Although not shown, the bracket assembly  66  preferably includes an additional locking pin slidably received in a second set of axially aligned apertures to lock the platform  16  in the selected vertical position. It is within the ambit of the present invention to utilize various alternative locking mechanisms and exemplary pin-type mechanisms are disclosed in the Wyse &#39; 334  application previously incorporated herein.  
      The sleeve  74  is fixed to the rail  58  by a block  80  and by a gusset  82 . In this manner, the rail  58 , and thus the work surface  62  supported thereon, slides with the sleeve  74  relative to the frame  12 . The block  80  is open on its upper end and includes means for securing attachment components in the block  80  (e.g., the illustrated block  80  is configured to receive a guard rail (not shown) and includes a pin-receiving aperture to removably secure the guard rail in the block  80 ). The gusset  82  provides additional support to the rail  58  relative to the sleeve  74 .  
      One exemplary platform is disclosed in the previously incorporated Wyse &#39; 334  application. However, the platform could be variously constructed and configured, for example, the platform need not be adjustable, and could be fixedly supported along the frames, or on top of the frames.  
      The illustrated scaffolding  10  is a mobile scaffolding. In more detail, each of the frames  12 , 14  are supported by a corresponding pair of the casters  18 , 20  and  22 , 24 , respectively. Each of the casters  18 , 20 , 22 , 24  are virtually identically configured and therefore only the caster  18  will be described in detail with the understanding that the casters  20 , 22 , 24  are similarly constructed. The caster  18  is swively received in the open lower end of the post  34  of the frame  12 . In one manner known in the art, the caster  18  includes a caster housing  84 , a stub shaft  86  swively coupled to the housing  84 , and a wheel  88  rollably supported in the housing  84 . The caster housing  84  supports the post  34  on the wheel  88 . The stub shaft  86  is removably received in the open lower end of the post  34  and is configured to be locked in the post  34 . For example, the illustrated shaft  86  includes an aperture (not shown) that aligns with the lower-most pin-receiving passageway formed by the bottom apertures  38  in the post  34 . In this manner, a retaining pin (not shown) can be inserted through the post  34  and the stub shaft  86  to retain the shaft in the lower end of the post  34 . The stub shaft  86  includes a bearing ring formed in its lower end that carries a bearing (not shown) to allow the caster housing  84  and thus the wheel  88  to swivel relative to the stub shaft  86  while still supporting the weight of the frame  12  and the platform  16  carried by the post  34 . The wheel  88  is axled to the housing  84  so that the wheel  88  is free to roll relative thereto. In this manner, the casters  18 , 20 , 22 , 24  cooperate to provide mobility to the scaffolding  10 . It is within the ambit of the present invention to utilize various alternatively configured means for providing mobility to the scaffolding  10 . However, it is important that the scaffolding be enabled to move relative to the supporting floor or ground surface S.  
      The mobile scaffolding  10  can be prevented from moving relative to the supporting floor or ground surface S by the brake assemblies  26 , 28 , 30 , 32  associated with each of the casters  18 , 20 , 22 , 24 . The inventive brake assemblies  26 , 28 , 30 , 32  enable the worker to select and control when the mobile scaffolding  10  is prevented from moving while the worker is elevated on the platform  16 . Each of the brake assemblies  26 , 28 , 30 , 32  are virtually identically configured and therefore only the brake assembly  26  will be described in detail with the understanding that the brake assemblies  28 , 30 , 32  are similarly constructed. The illustrated brake assembly  28  includes a lower brake housing  90 , an upper brake housing  92 , a brake stop subassembly  94 , a plunger  96 , and a handle subassembly  98  (see  FIGS. 1-2 ). In more detail, and as shown in  FIGS. 3-4 , the lower brake housing  90  includes a bracket  100  that is coupled to the lower end of the post  34  of the frame  12  adjacent the caster  18 . The illustrated bracket  100  is bolted to the post  34  through a pair of the pin-receiving passageways formed by the aligned apertures  38  in the post  34 . The lower brake housing  90  further includes a transverse bar  102  fixed to the bracket  100  and extending generally orthogonally therefrom. For purposes that will described below, the bar  102  is dimensioned and configured so that its distal end (the end opposite the bracket  100 ) extends over and sufficiently past the wheel  88  of the caster  18 . For purposes that will subsequently be described, the lower brake housing  90  includes a tubular sleeve  104  fixed to the distal end of the transverse bar  102 . The illustrated sleeve  104  extends generally parallel to the post  34  of the frame  12  and is open along its entire axial length and at both its upper and lower ends. For purposes that will subsequently be described, the sleeve  104  includes a vertical slot  104   a  formed in the tubular wall of the sleeve  104  and configured to slidably receive a pin or bolt so that the pin and/or bolt received in the slot  104   a  passes through the sleeve  104  and extends out of the tubular wall of the sleeve  104  at diametrically opposite locations. As will be described below, the lower brake housing  90  further includes a fulcrum post  106  fixed to and extending upwardly from the transverse bar  102 . The fulcrum post  106  is spaced from the sleeve  104  and positioned between the bracket  100  and the sleeve  104 .  
      The upper brake housing  92  is coupled to the upper end of the post  34  of the frame  12  and includes a bracket  108  and a bushing block  110 . The illustrated bracket  108 , similar to the bracket  100 , is bolted to the post  34  through a pair of the pin-receiving passageways formed by the aligned apertures  38  in the post  34 . The bracket  108  includes a portion  108   a  that extends generally transversely from the post  34  and includes an opening (not shown). The bushing block  110  is fixed to the bracket portion  108   a . In the illustrated upper brake housing  92 , the bushing block includes a section that extends through the opening in the bracket portion  108   a  and includes external threads that receive a bushing block nut  110   a  to couple the bushing block  110  to the bracket portion  108   a . As will be subsequently described, the bushing block  110  is configured to slidably receive at least a portion of the plunger  96 .  
      The lower and upper brake housings  90 , 92  are removably couplable to the frame  12 . In this regard, the brake assembly  26  can be easily added on, or coupled to, existing scaffolding. However, it is within the ambit of the present invention to utilize various alternative configurations for the brake housings  90 , 92 . For example, the housings could be integrally formed with the scaffolding frame during the original manufacture thereof.  
      The brake stop subassembly  94  is shiftably coupled to the lower brake housing  90  and is shiftable between a braking position as shown in  FIG. 4 , wherein the wheel  88  of the caster  18  is generally prevented from moving relative to the floor or ground support surface S, and a release position as shown in  FIG. 3 , wherein the wheel  88  is free to move. Particularly, the brake stop subassembly  94  includes a pivot bar  112 , an upper tube  114 , a lower shaft  116 , and a brake stop  118 . The pivot bar  112  presents a proximate end  112   a  generally adjacent the post  34  of the frame  12 , and an opposite, distal end  112   b  spaced from the proximate end  112   a . The pivot bar  112  is pivotally coupled to the fulcrum post  106  of the lower brake housing  90  generally between the ends  112   a,b  of the pivot bar  112 . The illustrated pivot bar  112  presents a pair of side panels, spaced apart by a cross bar  112   c , that straddle the fulcrum post  106  and are bolted together through the post  106 . When the brake stop subassembly  94  is in the release position, the pivot bar  112  is generally parallel to the transverse bar  102  of the lower brake housing  90  (see  FIG. 3 ). When the brake stop subassembly  94  is in the braking position, the proximate end  112   a  of the pivot bar  112  is further spaced from the transverse bar  102  and the distal end  112   b  is closer to the transverse bar  102  (see  FIG. 4 ). For purposes that will subsequently be described, formed in the distal end  112   b  of the pivot bar  112  is a longitudinally extending bolt-receiving slot  112   d.    
      The upper tube  114  of the brake stop subassembly  94  is slidably received within the sleeve  104  of the lower brake housing  90 . The upper tube  114  includes three pins fixed relative to the tube  114  and extending diametrically through the center of the tube  114 , an upper pin  120 , an intermediate pin  122 , and a lower pin  124 . The upper end of the tube  114  is received between the side panels of the pivot bar  112  and the upper pin  120  extends through the upper end of the tube  114  so that it is slidably received within the bolt-receiving slot  112   d  of the pivot bar  112 . In this manner, when the pivot bar  112  pivots, the movement of the distal end  112   b  causes the upper tube  114  to slide relative to the sleeve  104 . For purposes that will subsequently be described, the intermediate pin  122  extends through the tube  114  and is positioned so that it is slidably received in the vertical slot  104   a  of the sleeve  104 . As will subsequently be described, the lower pin  124  is positioned adjacent the lower end of the tube  114 . The lower pin  124  need not necessarily extend through the outer wall of the tube  114 . However, as will become apparent below, for assembly purposes, the lower pin  124  is preferably inserted after the lower tube  116  is slidably received inside the upper tube  114  (e.g., spring-biased and/or detented against the inside wall of the sleeve  104 , etc.).  
      The lower shaft  116  is slidably received within the lower end of the upper tube  114  so that the lower end of the shaft  116  extends out of the lower end of the upper tube  114 . Particularly, the lower shaft  116  includes a horizontal slot  116   a  formed in its wall that is configured to slidably receive the lower pin  124  of the upper tube  114 . In this manner, the lower shaft  116  has a limited range of slidable motion relative to the upper tube  114 , yet still is caused to generally shift relative to the sleeve  104  when the upper tube  114  shifts relative to the sleeve  104 . The lower shaft  116  slides relative to the upper tube  114  between an extended position as shown in  FIG. 3 , wherein the shaft  116  is extends out of the upper tube  114  until the top of the slot  116   a  engages the lower pin  124  of the upper tube  114 , and a retracted position as shown in  FIG. 4 , wherein the shaft  116  retracts into the upper tube  114  until the bottom of the slot  116   a  engages the lower pin  124  of the upper tube  114 . The lower shaft  116  is spring biased into the extended position by a spring  126 . The top end of the spring  126  rides against the intermediate pin  122  of the upper tube  114  and the lower end of the spring  126  rides against the upper end of the shaft  116 . In this manner, the spring force of the spring  126  must be overcome to cause the shaft  116  to slide into the retracted position as shown in  FIG. 4 . For purposes that will be described below, the lower end of the shaft  116  includes internal threading.  
      The brake stop  118  is fixed to the lower end of the shaft  116  and thus is caused to move with the shaft  116 . The stop  118  includes a threaded shaft  128  and a disk  130 . The upper end of the threaded shaft  128  threads into the internal threads of the lower end of the shaft  116  and the lower end of the threaded shaft  128  is coupled to the disk  130 . The illustrated stop  118  includes locking nuts  132  so that the position of the stop  118  relative to the lower shaft  116  can be adjusted and locked into the desired position once adjusted. The disk  130  presents a relatively flat bottom surface that engages the floor or ground support surface S when the brake stop subassembly  94  is in the braking position (see  FIG. 4 ) and is spaced from the floor or ground surface S when the subassembly  94  is in the release position (see  FIG. 3 ). The engagement between the disk  130  and the floor or ground surface S prevents the wheel  88  of the caster  18  from moving relative thereto. Accordingly, the disk must be sufficiently strong to withstand engagement with the surface S and the bottom surface of the disk  130  is preferably formed from a material having gripping properties such as various plastic polymers, rubber, etc. The illustrated disk  130  is formed from metal (e.g., steel, aluminum, etc.) and covered with an industrial grade softer rubber. The range of motion provided between the extended and retracted positions of the lower shaft  116  enables the disk  130  to grippingly engage a floor or ground surface that is not uniformly even. However, the disk  130  preferably is pivotal relative to the threaded shaft  128  (e.g., coupled thereto with a ball joint, etc.) to facilitate gripping engagement of uneven support surfaces. Additionally, the spring force of the spring  126  facilitates the gripping engagement of the disk  130  with the floor or ground surface S.  
      The plunger  96  extends between the lower and upper brake housings  90 , 92  and transfers movement of the handle subassembly  98  to the brake stop subassembly  94 . In this regard, the illustrated plunger  96  is a rigid rod presenting a bottom end  96   a  and an opposite, spaced top end  96   b . The bottom end  96   a  is pivotally coupled to the proximate end  112   a  of the pivot bar  112  of the brake stop subassembly  94 . The bottom end  96   a  of the illustrated plunger  96  includes a collar  96   c  that is received between the side panels of the pivot bar  112  and rotatably receives a bolt  132  coupled to the panels of the bar  112  (see  FIGS. 3 and 4 ). The top end  96   b  is slidably received through the bushing block  110  of the upper brake housing  92 . The top end  96   b  of the illustrated plunger  96  includes a stub shaft  96   d  that is dimensioned and configured to slide within the opening of the bushing block  110  and extend out of the top and bottom of the bushing block  110 . In this manner, the stub shaft  96   d  can be formed from a strong durable material that can be machined to the desired size (e.g., steel, etc.) while the other portions of the plunger  96  can be formed from a relatively cheaper, light weight material (e.g., various plastic polymers, etc.).  
      Turning to  FIGS. 5-7 , the handle subassembly  98  is coupled to the upper brake housing  92  and enables a worker supported on the scaffolding  10  to shift the brake stop subassembly  94  into and out of the braking position to selectively prevent movement of the scaffolding  10 . In more detail, the handle subassembly  98  includes a handle  134  and a guide bracket  136 . The handle  134  is generally L-shaped and presents a grip  134   a  at one end and a coupling fork  134   b  that elbows out of the opposing end. The coupling fork  134   b  is pivotally coupled to the top end portion of the stub shaft  96   d  of the plunger  96  that extends out of the top of the bushing block  110 . The guide bracket  136  is pivotally coupled to the elbow of the handle  134  at one end and pivotally coupled to the bushing block  110  at the opposite end. The handle  134  is pivotal from the position shown in  FIG. 5 , wherein the grip  134   a  is oriented toward the post  36  of the frame  12  and somewhat parallel to the rung  52  of the frame  12 , to the position shown in  FIG. 7 , wherein the grip  134   a  is oriented away from the post  36  and somewhat parallel with the rung  52 , with the position shown in  FIG. 6  being the intermediate, center position, wherein the grip  134   a  is not at all parallel with the rung  52 . When the handle  134  is in the position shown in  FIG. 5 , the top end  96   b  of the plunger  96  is adjacent the bushing block  110  corresponding to the brake stop subassembly  94  being in the release position as shown in  FIG. 3 . As the handle  134  is pivoted toward the center position shown in  FIG. 6 , the weight of the plunger  96  must be overcome and the top end  96   b  of the plunger  96  is caused to slide up and away from the top of the bushing block  110 . As the fork  134   b  pivots relative to the plunger end  96   b , the elbow of the handle  134  pivots relative to the guide bracket  136 . In this manner, the handle subassembly  98  transfers only straight-line motion to the plunger  96 . As the handle  134  is pivoted past the center position shown in  FIG. 6 , the handle  134  is urged into the position shown in  FIG. 7 . When the handle  134  is in the position shown in  FIG. 7 , the top end  96   b  of the plunger  96  is spaced upwardly from the top of the bushing block  110  corresponding to the brake stop subassembly  94  being in the braking position as shown in  FIG. 4 . The weight of the plunger  96  and the configuration of the handle subassembly  98  cooperate to maintain the handle  134  in the position shown in  FIG. 7 . In order to pivot the handle  134  back into the position shown in  FIG. 5 , the weight of the plunger  96  must again be overcome until the handle  134  pivots past the center position shown in  FIG. 6 . Once the handle  134  pivots past the center position, the weight of the plunger  96  urges the handle  134  back into the position shown in  FIG. 5  and maintains the handle  134  in that position. In this regard, the illustrated handle subassembly  98  is a straight-line over-the-center-type clamp. One such suitable clamp is available from DE-STA-CO Industries of Madison Heights, Mich. as Model No. 604.  
      As previously indicated, the braking assemblies  28 , 30 , 32  are virtually identically configured as the braking assembly  26 . However, it is within the ambit of the present invention to utilize a single braking assembly, or the inventive braking assembly in combination with traditional caster brakes, as well as various alternatively configured braking assemblies. For example, the brake assembly need not utilize a brake stop that engages the ground to prevent movement of the scaffolding, but rather could implement traditional-type brake stops that engage the wheel to prevent movement. Additionally, the brake assembly need not utilize a pivotal handle or a rigid plunger to activate the brake stop. For example, the brake assembly could utilize an electronically activated brake stop with a remotely located controller, or hard wire linkage. However, it is important that the brake stop be capable of activation by the worker while the worker is supported on the scaffolding in order to prevent movement of the scaffolding.  
      In operation, the scaffolding  10  is assembled and rolled into the desired work position on the supporting floor or ground. The worker then mounts the scaffolding  10  (e.g., by climbing up the rungs  44 , 46 , 48 , 50 , 52 ) so that the worker is supported on the platform  16 . In order to activate the braking assembly  26 , the worker grasps the grip  134   a  of the handle  134  and pivots the handle  134  from the position shown in  FIG. 5  to the position shown in  FIG. 7 . As the handle  134  is pivoted, the plunger  96  is pulled upward. As the plunger  96  is pulled upward, the brake stop subassembly  94  is caused to shift from the release position shown in  FIG. 3  to the braking position shown in  FIG. 4 . The braking assemblies  28 , 30 , 32  can be similarly activated. The mobile scaffolding  10  is now prevented from moving and the worker is securely supported on the platform  16  for safe working. If the worker desires to deactivate one or more of the braking assemblies, the above described steps are simply reversed. Once the braking assemblies are deactivated, the mobile scaffolding  10  can be rolled to the next desired work position (e.g., the supported worker can pull the scaffolding  10  along the supporting surface S). Once the scaffolding  10  is repositioned, the worker can reactivate the braking assemblies from the platform  16 .  
      The preferred forms of the invention described above are to be used as illustration only, and should not be utilized in a limiting sense in interpreting the scope of the present invention. Obvious modifications to the exemplary embodiments, as hereinabove set forth, could be readily made by those skilled in the art without departing from the spirit of the present invention.  
      The inventors hereby state their intent to rely on the Doctrine of Equivalents to determine and assess the reasonably fair scope of the present invention as pertains to any apparatus not materially departing from but outside the literal scope of the invention as set forth in the following claims.