Abstract:
A safety ladder cage system is of a fabricated construction to reduce the time and expertise to provide a safety cage to one side of a scaffold system access ladder. The safety cage system is divided into two components each of which can be carried by a worker to the appropriate point and loosely hung from a ladder rung or the ladder uprights. The worker is then free to accurately position the safety cage component to one side of the ladder. The second component is then brought into position and attached to the opposite side of the ladder in a similar manner. The components are then attached to each other along vertical securing edges outwardly spaced from and generally centered on the ladder. Each component preferably includes its own captured connector for engaging the opposite component.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to scaffolding systems and in particular, to ladder systems associated with scaffolding systems to provide safe access-thereto.  
       BACKGROUND OF THE INVENTION  
       [0002]     Ladders are commonly used to access raised work platforms associated with scaffolding systems. Generally, once the ladder exceeds a certain height from the ground, a safety structure must be provided about the ladder to provide protection for a user and to act as a safety cage behind a user such that he cannot fall rearwardly off the ladder without being restricted by the safety cage.  
         [0003]     Scaffolding systems have designed a number of approaches for providing a safety structure to one side of the ladder to protect the worker. On many construction sites, workers fabricate an enclosed structure by means of a series of vertical elements extending in a parallel manner to the ladder with a series of horizontal components attached to the scaffolding and the vertical elements. In this way, it is possible for the worker to use the verticals and horizontals of the scaffolding system to fabricate a safety structure to one side of the ladder. These structures are certainly satisfactory in providing the required safety structure to one side of the ladder, however, they are costly to assemble and in many cases, are over designed. With scaffolding systems, there is a substantial cost to initially assemble the system and a lower cost associated with taking the system down. Therefore, there is a high cost component in assembling onsite fabricated ladder cages as they are all done by hand and have a substantial labour component. In designing these systems, care is required to make sure the system components are easy to install and are of a weight which is easily carried by a worker. Obviously, the assembly of these safety structures can be at a substantial height and could expose the worker to a substantial risk.  
         [0004]     The present invention provides an effective structure and method for assembling a safety cage to one side of a scaffold ladder.  
       SUMMARY OF THE INVENTION  
       [0005]     A safety cage for a scaffold ladder according to the present invention comprises a series of safety cage sections spaced in the length of the ladder and cooperating with the ladder to provide safety enclosure to one side of the ladder. Each section is vertically split with one cage component on one side of the vertical split and the second cage component on the other side of the vertical split. Each cage component includes a releasable mechanical securement engagable with the other respective cage component at the vertical split to secure the components one to the other. Each component further includes a releasable mechanical securement at a free edge of the component in engagement with the ladder.  
         [0006]     According to an aspect of the invention, each component is supported by a rung of the ladder.  
         [0007]     In yet a further aspect of the invention, each cage component at the free edge thereof includes a hook for initial placement over a ladder rung for temporary hanging of the component from the rung of the ladder.  
         [0008]     In yet a further aspect of the invention, the cage components are of the same shape and are interchangeable.  
         [0009]     In yet a further aspect of the invention, each component at the free edge thereof includes two hook connectors with one hook connector facing downwardly and one hook connector facing upwardly.  
         [0010]     In a further aspect of the invention, each hook connector includes a vertically U-shaped channel which straddles a vertical support of the ladder.  
         [0011]     In yet a further aspect of the invention, each hook connector includes a captured mechanical fastener for effecting securement of the connector to the ladder.  
         [0012]     In a further aspect of the invention, the ladder comprises two upright members connected by a series of ladder rungs. Each upright member is of a U-shaped cross section facing outwardly with the rungs of the ladder intersecting with the base of each U-shaped cross section.  
         [0013]     In a further aspect of the invention, the U-shaped ladder uprights members each have a series of holes in the base of the U-shaped section with the series of holes being spaced in the length of the ladder.  
         [0014]     In yet a further aspect of the invention, each ladder upright member has inwardly extending flanges either side of the U-shaped cross section to thereby form a restricted connecting structure in each ladder upright member. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]     Preferred embodiments of the invention are shown in the drawings, wherein:  
         [0016]      FIG. 1  is a partial perspective view showing a scaffolding system and associated access ladder;  
         [0017]      FIG. 2  is a view similar to  FIG. 1  where part of the safety cage associated with the access ladder is still required to be positioned;  
         [0018]      FIG. 3  is a partial perspective view showing securement of the safety cage section to an access ladder;  
         [0019]      FIG. 4  is a perspective view of the safety cage section;  
         [0020]      FIG. 5  is a perspective view of a new ladder and connection system;  
         [0021]      FIG. 6  is a perspective view of the new ladder attached to a scaffolding structure;  
         [0022]      FIG. 7  is a perspective view showing additional details of a ladder connecting bracket;  
         [0023]      FIG. 8  is a partial top view of a ladder with the connecting bracket attached to a scaffold rosette;  
         [0024]      FIGS. 9 through 12  show different attachment clamps for the ladder cage; and  
         [0025]      FIGS. 13 and 14  are perspective views of the new ladder attachment to a scaffolding system and including a safety cage. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]     The scaffolding system generally shown as  1  has a series of upright standards interconnected by generally horizontal ledgers. The upright standards include a rosette at selective vertical spacings which are used for connection of the ledgers to the uprights. A work surface can be provided at different heights and is supported by the ledgers. In the arrangement shown in  FIG. 1 , the ladder  4  is connected to the scaffolding system  1  by means of additional horizontal tubular members  100  secured to the scaffolding system  1 , by ladder brackets  102  secured to members. Basically the ladder  4  can be produced in a series of discrete segments with these segments connectable in an end to end manner to define a ladder of a desired length. The ladder can be supported in a number of different ways to one side of the scaffolding system  1 .  
         [0027]     Once the ladder is in place and properly supported by the scaffolding system it is usually necessary to assemble a safety cage  2  to one side of the ladder. Different labour laws require a safety cage once the ladder exceeds a certain height. With the present system, a series of safety cage sections  6  are secured to the ladder and are spaced in the length of the ladder. The sections do not need to abut one to the other and some vertical spacing between the sections is permitted.  
         [0028]     Each section  6  has a first section component  8  and a second section component  10 . These section components are identical and one section has merely been reversed and assembled to the opposite side of the ladder. These section components are joined at the vertical split  12  by means of an upper connector  14  and a lower connector  14 . The upper connector at  FIG. 1  is associated with the right hand section and the lower mechanical connector is associated with the left hand section. The connector  14  is captured on section  8  and includes a T-head for insertion through a slot and rotation to engage the vertical flange of the opposite section.  
         [0029]     The section components  8  and  10  each include at the free edge  20  thereof, hook connectors  22  and  24 . Hook connector  22  is shown as facing downwardly, and hook connector  24  is facing upwardly. Connector  24  will form the upper connector when this section is used for defining a left hand section. These hook connectors  22  and  24  allow a worker to carry the section to the appropriate point on the ladder and temporarily secure the section to the ladder by placing the hook connector over a rung of the ladder with the upright portion of the ladder fitted within this connector. With this arrangement, the lower connector which has a U-shaped section, also engages and straddles the upright member of the ladder. Once this section has been temporarily secured on the ladder, the worker can then adjust the section and positively secure it to the ladder by pushing the section at the top towards the ladder allowing the pin to be placed behind the upright to close the connector and the wedge driven downwardly to provide positive engagement. Once this has been accomplished, the lower connector can also be fastened. The pin is a captured member with a “T” shaped bolt head for releasably engaging one side of the upper connector.  
         [0030]     Once a first section has been secured, the opposite section can then be brought up and placed on the ladder. Once again, it is temporarily secured and then positively secured to the ladder. Once so located, the vertical split between the two sections are generally aligned. The worker can then use the wedges with the T-shaped bolts for securing the vertical split between the sections by means of the two connectors. This can be accomplished in a fast and effective manner and represents a significant labour saving over the construction of an onsite fabricated safety cage which is fabricated each time a ladder is erected.  
         [0031]     Each section includes a top band  50 , a lower band  60 , and a series of interconnected vertical members  55 . Each cage section is a fabricated component and allows for quick assembly and disassembly from an access ladder.  
         [0032]     Turning to  FIG. 2 , it can be seen that the access ladder  4  extends above the work surface  120  and a full safety cage section  6  is shown with a single section component  8  secured to the right hand side of the ladder without a corresponding section  10 . In this case, access to the work surface  120  is desired. Therefore, after section  8  has been assembled to the ladder, a safety cage exit section  74  is secured to the section  8 . The exit section includes an upper band member  76 , a lower band member  78 , a securing tubular member  80  and at least one upright  82 . The exit section includes a vertical securing face  84  for cooperating with the section  8 . A similar mechanical connection is made at the vertical split and the exit section  74  is secured to ledgers  90  and  92  by clamps  86  and  88 . With this arrangement, a safety cage structure is defined and the cage structure provides convenient access to adjacent workspaces while still providing a safe environment. Details of the safety cage sections and the various securing brackets are shown in  FIG. 3 .  
         [0033]     The safety cage system, as shown in  FIGS. 1 through 4 , can be used with many scaffolding systems as the structure of access ladders is similar. In addition, the connectors at the free end of each section can be shaped for specific ladders and scaffolding systems. The system uses the rungs and uprights of the ladder to simplify the securement of the safety cage sections and provides an effective arrangement for many different types of scaffolding systems.  
         [0034]     In  FIG. 5 , a new ladder structure  200  is shown with its own securing arm  250 . The ladder  250  has a series of rungs  202  which interconnect the two upright members  204 . Each of these upright members are of an outwardly opening U-shape with the base of the U connected to the rungs  202 . The U-shaped upright members  204  also have the outer edges of the U partially closed by inwardly directing flanges  206  and  208 . This arrangement provides an outwardly opening securing slot which is used with a bolt having a T-head for effecting securement of the ladder as will be more fully described. In addition, each of the upright members  204  has a series of holes  210  extending in the length of the ladder.  
         [0035]     The securing arm  250  is engagable with the upright members  204  of the ladder at a number of points along the length of the upright member. The securing arm  250  includes a mechanical fastener  260  defined by a bolt  262  which receives the captured wedge  264  with the bolt  262  having a T-head received and retained within the securing slot. In addition, the securing arm  250  includes a projecting stop  266  which is received in one of the holes  210 . As shown, this stop is in engagement with a lower part of the slot  210 . Once the arm has been temporarily located at an appropriate point for securement to a rosette, such as the rosette  290  in  FIG. 6 , the fastener  260  can be initially brought in engagement with the slot of the upright. The wedge member is generally in a horizontal position such that the T-head of the bolt aligns with the slot opening. It is then inserted in the slot and the wedge is rotated 90 degrees and thus rotates the bolt head 90 degrees. The wedge is then driven downwardly through the bolt and draws the T-head into engagement with the slot. There is no sliding of the securing arm along the upright due to the stop  266  engaging a lower portion of the hole  210 . The securing arm can then be secured to the rosette  290  as shown in  FIGS. 6 and 8 . The T-head of the bolt is shown at  265  at  FIG. 8 .  
         [0036]     The structure of  FIGS. 5 through 8  has particular application with scaffolding systems having a series of rosettes as shown in  FIG. 1 . The ladder of  FIGS. 5 through 7  in addition to the engaging of the securing arm  250  is adapted to cooperate with the safety cages shown in the earlier drawings. In this case, the fasteners at the free edge of the safety cage are altered to specifically to cooperate with the modified ladder. A right hand top hook is shown in  FIG. 9 , a left hand top hook is shown in  FIG. 10 , a bottom right hand clamp is shown in  FIG. 11  and a bottom left hand clamp is shown in  FIG. 12 . The hook portions are adapted to be received in and retained by one of the series of holes  210  in the upright members. The bottom clamps are adapted to engage the securing slot of the upright members in a manner similar to the securing arm  250 .  
         [0037]      FIG. 13  shows the safety cage secured to the ladder  250 . The hook fasteners pass through any of the holes  210  and the lower clamping members engage the securing slot. In this case, the ladder safety cage sections do have a left hand component and a right hand component. The actual ladder section without the fasteners at the free edge thereof, is not right handed or left handed but the securing of the clamps will render the section a right hand section or a left hand section.  
         [0038]      FIG. 14  shows the preferred ladder structure engaging the scaffolding system with a series of cage sections and an exit section.  
         [0039]     Although various preferred embodiments of the present invention have been described herein in detail, it will be appreciated by those skilled in the art, that variations may be made thereto without departing from the spirit of the invention or the scope of the appended claims.