Patent Publication Number: US-8109363-B2

Title: Modular retaining wall fall protection system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Provisional Application No. 60/465,954 which was filed Apr. 28, 2003, which is entitled “Modular Retaining Wall Fall Protection System”, and which is incorporated herein by reference. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable. 
     BACKGROUND OF THE INVENTION 
     The Occupational Safety and Health Administration requires that retaining walls being built over a specified height must use a retaining wall fall protection system to prevent those building the wall from being injured by a fall. However, no retaining wall fall protection systems exist which allow the retaining wall builder to quickly assemble and disassemble a protection system and be able to quickly change the configuration of the protection system to protect workers as the wall is being built. As such, there is a need for a retaining wall fall protection system of the present invention. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention comprises a retaining wall fall protection system comprising a plurality of base plates held in position by a retaining wall. It further includes a plurality of uprights pivotally attached to the base plates and a cross-brace attached to adjacent uprights at opposite ends of the cross-brace. A plurality of guardrails are provided and attached to guardrail adjustment brackets. The guardrail brackets are removably attachable to the uprights at various positions along the length of the uprights. Finally, there is provided an attachment assembly which secures the uprights in position adjacent the retaining wall. 
     The attachment assembly comprises an attachment strap which is adapted at one end to be connected to the scaffolding upright. Preferably, a standoff bracket is provided to which the attachment strap is connected. The attachment strap is adapted at its opposite end to be connected to the retaining wall being constructed. The attachment strap can be connected directly to the wall, for example, to an alignment key on the blocks from which the wall is made. 
     Alternatively, and preferably, the attachment strap extends through the wall. A retainer on the opposite side of the wall engages a distal end of the attachment strap to secure the scaffolding to the retaining wall under construction. The strap can be in the form of a rod which is threaded or grooved at its distal end. In this case, the retainer includes a threaded portion or acts in a ratcheting manner to engage the strap. In a preferred alternative, the retaining strap includes a slot at is distal end and the retainer includes a wedge. The strap passes through the retainer, and the wedge is inserted in the slot, such that one edge of the wedge engages a far surface of the strap slot and an opposite edge of the wedge engages the retainer. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is plan view of an assembled retaining wall fall protection system according to an embodiment of the present invention; 
         FIG. 2  is side view of an assembled retaining wall fall protection system according to an embodiment of the present invention used with a vertical retaining wall; 
         FIG. 3  is side view of an assembled retaining wall fall protection system according to an embodiment of the present invention used with a sloped retaining wall; 
         FIGS. 4A and 4B  are front and side elevational views of an upright for use with a retaining wall fall protection system according to an embodiment of the present invention; 
         FIGS. 5A and 5B  are a top and side plan views, respectively, of a base plate for use with a retaining wall fall protection system according to an embodiment of the present invention having a retaining wall block placed thereon; 
         FIGS. 6A and 6B  are plan views of a coupling tube for use with a retaining wall fall protection system according to an embodiment of the present invention; 
         FIGS. 6C and 6D  are section views of the coupling tube taken along lines C-C and D-D, respectively, of  FIG. 6B ; 
         FIGS. 7A and 7B  are front and side views of a gravity pin in use with an upright according to an embodiment of the present invention; 
         FIG. 7C-F  are top plan, side elevational, front elevational and perspective views, respectively of the gravity pin; 
         FIG. 8  is a plan view of a cross-brace for use with a retaining wall fall protection system according to an embodiment of the present invention; 
         FIG. 9  is a plan view of an A-type guardrail for use with a retaining wall fall protection system according to an embodiment of the present invention; 
         FIG. 10  is a plan view of a B-type guardrail for use with a retaining wall fall protection system according to an embodiment of the present invention; 
         FIGS. 11A and 11B  are front and right side plan views of a guardrail bracket for use with a retaining wall fall protection system according to an embodiment of the present invention; 
         FIGS. 12A and 12B  are front and right side plan views of a standoff bracket for use with a retaining wall fall protection system according to an embodiment of the present invention; 
         FIG. 12C  is a perspective view of the standoff bracket mounted to a scaffolding upright; 
         FIGS. 13A and 13B  are front and side plan views of a wall attachment assembly for securing scaffolding uprights to the retaining wall being constructed, the attachment assembly comprising a connecting member and a retainer; 
         FIG. 14  is a side view of a wall attachment assembly and a standoff bracket in position relative to a retaining wall fall to secure scaffolding to the retaining wall; 
         FIG. 15  is a back elevational view of a wall attachment assembly and a standoff bracket in use with a curved retaining wall; 
         FIG. 16  is a top plan view of a wall attachment assembly and standoff bracket in use with a curved retaining wall; 
         FIG. 17  is an exploded view of an alternative wall attachment assembly; 
         FIGS. 18 and 19  are top plan and side elevational views showing the wall attachment assembly of  FIG. 17  mounted to a stand-off bracket and with a connecting strap extending through the retaining wall, the wall being shown in phantom; 
         FIGS. 19A-C  are rear perspective, top plan, and front elevational views of a retainer for use with the attachment assembly of  FIG. 17 ; 
         FIG. 19D  is a cross-sectional view of the retainer taken along line  19 D- 19 D of  FIG. 19C ; 
         FIG. 20  is a perspective view of an another alternative attachment assembly for use with an open-walled system; and 
         FIG. 21  is a perspective view showing the retainer of the attachment assembly of  FIG. 20  mounted to a wall block. 
     
    
    
     Corresponding reference numerals will be used throughout the several figures of the drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     While the invention is susceptible of embodiment in many different forms, there is described in detail preferred embodiments of the invention. It is to be understood that the present disclosure is to be considered only as an example of the principles of the invention. This disclosure is not intended to limit the broad aspect of the invention to the illustrated embodiments. The scope of protection should only be limited by the claims. 
     Referring to  FIGS. 1 and 2 , the present invention comprises a fall protection system  10  for protecting workers while they are building a retaining wall  12  made from blocks  13 . As will be apparent, the fall protection system  10  comprises a scaffolding system which, using brackets and attachment assemblies as described below, is secured to the wall  12 . Upon completion of the wall  12 , the scaffolding is removed from the wall. 
     The system  10  generally comprises base plates  14  each having an upright assembly  15  made from uprights  16  attached to the base plates  14 . The adjacent uprights  16  are connected by cross-braces  18  and guardrails  20  which extend between the uprights  16 . Referring to  FIGS. 4A and 4B , each upright  16  comprises a tube having several holes  22  formed therein. The upright  16  further comprises toggle studs  26 . 
     Referring to  FIGS. 1 ,  2 ,  5 A and  5 B, base plates  14  are placed upon the ground and the retaining wall  12  is built upon a portion of the base plate  14  thus securing it in place. As seen, the base plate  14  has a bottom surface  14   a  and front and back lips  14   b  and  14   c . The retaining wall block  13  rests against the back lip  14   b . The base plate  14  has a length greater than the depth of the block and extends forwardly of the block. Hence, the front lip  14   b  is forward of the front surface of the wall blocks  13 . The base plate  14  further includes a leveling screw  28  pivotally mounted to the base plate  14  to pivot in a plane generally perpendicular to the base plate  14 . A leveling nut  30  is threadingly mounted on the screw  28 . The leveling nut  30  has first and second diameters  32 ,  34 . The first diameter  32  is slightly smaller than the inside diameter of an end  24  of the upright  16  such that an upright  16  may be placed over the first diameter  32 . The second diameter  34  is larger than an outside diameter of the upright  16  such that when the upright  16  is placed over the first diameter  32 , it rests upon a shoulder  36  formed by the interface of the first diameter  32  and the second diameter  34 . In this manner, the height of the upright  16  may be adjusted with respect to other uprights  16  by turning the leveling nut  30  with respect to the leveling screw  28  and the base plate  14 . 
     Furthermore, referring to  FIGS. 4A-B  and  6 A-D, multiple uprights  16  may be attached at their ends to build longer upright assemblies  15  by placing a coupling tube  36  in the ends  24  of two uprights  16 . The coupling tubes  36  comprise square tube that has been compressed at its ends  38  such that the tube is narrower in one dimension at its ends than it is at its center  40 . For example, in  FIG. 6C , a coupling tube  36  originally having a outside dimensions of 1.477 inches square, is compressed in one direction at its ends such that one outside dimension is reduced to 1.416 inches. However, the center  40  of the coupling tube  36  is compressed very little, if any, as shown in  FIG. 6D . In this manner, coupling tubes  36  may be easily inserted into the ends  24  of the uprights  16  initially and provide an increasingly tighter fit as they are inserted farther in to the upright  16 . The coupling tube  36  further includes a pair of coupling pin holes  42  and a spring pin hole  44 . The coupling pin holes  44  align with holes  22  of the uprights such that gravity pins  46  ( FIGS. 7A-C ) may be inserted through the coupling tube  36  and the upright  16  to prevent them from becoming unattached. The spring pin hole  44  also aligns with a hole  22  of the upright  16  and has a spring loaded pin (not shown) disposed within the hole  44 . 
     Referring to  FIGS. 7A-C , the gravity pin  46  comprises a rod bent into the configuration shown. The pin includes an L-shaped mounting section  46   a  having a portion  46   c  which extends through the holes  22  and  42  of the upright  16  and coupling tube  36 , respectively, and a short leg  46   d  which extends generally perpendicularly from one end of the portion  46   c . A U-shaped section  46   b  extends from an end of the short leg  46   d  and is in a plane perpendicular to the plane of the mounting section  46   a . The U-shaped section  46   b  comprises a pair of short legs  46   e,f  joined by a section  46   g . The U-shaped section leg  46   e  extends the mounting portion leg  46   d . As best seen in  FIG. 7C , the leg  46   f  is parallel to, and longer than, the leg  46   e . Hence, the leg  46   f  crosses the plane of the mounting section  46   a . The pin  46  is inserted into the upright  16  in the position shown in the bottom of  FIGS. 7A and 7B  and is allowed to drop by the force of gravity to the position shown in the top of  FIGS. 7A and 7B . In the locked position, the U-shaped lock section extends around three sides of the upright  16  to prevent the pin  46  from being removed from the upright  16  without lifting the pin back to the “insert” position. As such, the pin  46  cannot accidentally be removed from the upright  16  by vibration or other accidental means. 
     A cross-brace  18  shown in  FIG. 8  comprises two lengths of rod  48  joined at their centers by a pin  50 . The rods  48  have flattened end portions  52  having a hole  54  therein. The cross-braces  18  are attached to the uprights  16  by placing the toggle studs  26  of the uprights  16  through the holes  54  of the cross-brace  18 . 
     Referring to  FIGS. 9 ,  10 ,  11 A and  11 B, guardrails  20  are attached to the uprights  16  by means of guardrail brackets  56 .  FIG. 9  illustrates guardrails  20  of the A-type and  FIG. 10  illustrates guardrails  20  of the B-type. B-type guardrails  20  comprise a tube having both ends  66  flattened and a hole  68  in one of the ends  66 . A-type guardrails comprise a tube having both ends  66  flattened and a hole  68  in each end  66 . Both the A- and B-type guardrails include holes at their centers through which the pin  50  can extend to pivotally connect two guardrails together. 
     Turning to  FIGS. 11A and 11B , the guardrail brackets  56  comprise a C-shaped channel  58  having a plurality of U-hooks  60  and toggle studs  62  attached thereto and extending from a front face of the channel member. Holes  64  are formed in the sidewall of the channel member. The toggle studs  62  each include an arm  62   a  and a finger  62   b  pivotally mounted to the end of the arm. The stud arm  62   a  and finger  62   b  are sized to allow the holes  54  of the cross-brace rods  48  and the holes  68  of the guardrail rods  20  to pass thereover. Hence, to place the cross-braces or the guardrails on the brackets  56 , the toggle stud is positioned so that the toggle stud arm and finger are aligned. The cross-brace rods or guard rail rods are then slid over the toggle stud, and, with the rod opening  54  or  68  positioned on the toggle stud arm, the toggle stud finger is rotated relative to the arm to prevent the rod from coming off the arm. 
       FIGS. 12A-B  show a standoff bracket  67  according an embodiment of the present invention. The standoff bracket  67  comprises a C-shaped channel member  68  having a hole  70  in its sidewall and a standoff  72  extending from its front face. The standoff  72  further comprises a wall attachment dowel  74 . The channel member is sized and shaped to be received on the scaffolding uprights  16 , and the hole  70  is sized and shaped to be aligned with the openings in the uprights such that a gravity pin  46  can pass through the bracket  67  and the upright  16 , as seen in  FIG. 12C  to maintain the bracket  67  on the upright. 
     An alternative standoff bracket  67 ′ is shown in  FIG. 12C . The bracket  67 ′ includes a channel member  68  identical to the channel member  68  of FIGS.  12 A,B. The standoff member  72 ′ however, is slightly different. Rather than being a straight rod, as is the standoff member  72 , the standoff member  72 ′ comprises a pair of members comprising a first portion  72   a  which extends generally perpendicularly from the front face of the channel member  68 . The first portions  72   a  of the two members are adjacent and parallel to each other. A second portion  72   b  extends generally perpendicular to the first member  72   a  in a generally horizontal plane. The second portions  72   b  of the two member extend away from each other. Lastly, third portions  72   c  extend rearwardly from the second portions to be generally parallel to each other and to the first potions  72   a . Hence, the stand off is generally “ ” in plan view. The attachment dowel  74  extends generally perpendicularly from the stand off first portion  72   a  to be generally parallel to the front face of the channel member  68 . Although the bracket  67 ′ is shown to be connected to the upright  16  with the attachment dowel member extending downwardly, the bracket  67 ′ can be connected to the upright with the attachment dowel  74  extending upwardly. 
       FIGS. 13A-B  show a wall attachment assembly  76 . The wall attachment assembly  76  comprises an attachment strap in the form of a threaded rod  78  having an eye  80  at one end. Threaded onto the threaded rod  78  is a retainer  82 . The eye  80  is sized to be able to fit over the attachment dowel  74  of the bracket  67 . Alternatively, the rod  78  could be grooved, rather than threaded, and the retainer  82  could be adapted to engage the grooves to provide a ratcheting type engagement between the rod  78  and the retainer  82 . 
     In order to assemble the retaining wall fall protection system  10  of the present invention, the user begins by assembling the wall  12  on top of the base plates  14 . As the wall  12  increases in height, the user adds uprights  16  by first placing uprights upon the leveling nuts  30 . Cross-braces  18  are attached to the toggle studs  26  of the uprights  16 , as noted above, to provide stability to the uprights  16 . Referring to  FIG. 14 , the threaded rod  78  of the wall attachment assembly  76  is fed through the wall  12  by pulling the rod  78  through a preexisting passage between the wall blocks  13 . The retainer  82 , which is too large to feed through the wall  12 , is threaded onto the rod  78 . The wall attachment rod  78  is attached to the standoff bracket  67  by inserting the dowel  74  through the eye  80 . The retainer  82  is threaded onto the rod  76  until the standoff  72  makes contact with the wall  12 . The standoff brackets  67  are attached to the uprights  16  with gravity pins  46  to mount the standoff brackets to the uprights the mounting section  46   a  of the gravity pin  46  passes through the holes  70  of the standoff bracket  67  of the upright  16 . In this manner, the fall protection system is supported by the wall  12  and maintained a predetermined distance from the wall. 
     Next, guardrail brackets  56  are attached to the uprights  16  with gravity pins  46 . This is accomplished by placing the C-shaped channel  58  of the guardrail bracket  56  over the upright  16  and aligning one of the holes  64  with holes  22  in the upright  16 . The gravity pin  46  is placed through these aligned pairs of holes  22 ,  64  and allowed to drop to the locked position. Furthermore, the A-type guardrails  20  are attached to the guard rail brackets  56  by inserting the guardrail end  66  without the hole  68  though the U-hooks  60  of the guardrail bracket  20  and attaching the guard rail end  66  with the hole  68  over the toggle studs  62  of the guardrail bracket  56  of the adjacent upright  16 . B-type guardrails  20  may be installed by place the holes  68  of each end  66  over toggle studs  62  of the guardrail brackets  56 . In this manner, the guard rails form a fence to protect workers from falling over the edge of the wall  12 . 
     As the wall  12  increases in height, the guardrails  20  must necessarily be raised and the uprights  16  lengthened. To lengthen the uprights  16 , coupling tubes  36  are inserted into the top end of the existing uprights  16  and a gravity pin is placed through aligned holes  22 ,  42  of the upright  16  and the coupling tube  36 . Another upright  16  is then placed over an exposed portion of the coupling tube  36  and another gravity pin placed through holes  22 ,  42  of the new upright  16  and the coupling tube  36 . The guardrail brackets  56  are then removed from the uprights  16  and reattached at a higher position upon the newly added uprights  16 . Alternatively, the guardrail brackets  56  can be left in place and additional guardrail brackets  56  can be added as the wall increases in height. Additional wall attachment assemblies  76  are mounted to the uprights  16  as needed to ensure that the uprights are secured against the wall  12 . 
     As can be seen from  FIG. 3 , the retaining wall fall protection system can be used with vertical retaining walls  12  as in  FIG. 2  or with sloped retaining walls  12  as in  FIG. 3  by virtue of the pivoting connection of the leveling screw  28  to the base plate  14 . 
     When the wall is completed the protection system  10  can be disassembled and removed from the wall  12 . All that will remain are the base plates  14  and the retainers  82  located between the back of the wall and the earth. 
     An alternative wall attachment assembly  100  is shown in  FIGS. 17-19D . The attachment assembly  100  comprises an attachment strap  102  having an eyelet  104  at one end and a slot  106  at the opposite end. The eyelet  104  is sized to fit over the attachment dowel  74  of the bracket  67  or  67 ′. The strap  102  is preferably formed from a material so that it will be flexible. A preferred material is a plastic, such as nylon. The strap  102  has length sufficient to extend through the retaining wall  12  as seen in FIGS.  18 A,B. The ends  102   a,b  of the strap  102 , where the eyelet  104  and slot  106 , respectively, are located, is thicker than the center section  102   c  of the strap. 
     The attachment assembly also includes a retainer  110  ( FIGS. 19A-D ) which is provided to be positioned on the back side of the retaining wall to receive the strap  102 . The retainer  110  includes a body  112  having a top surface  114 , bottom surface  116 , and side surfaces  118 . A front face  120  is formed at the front of the body  112 . As seen, the front face  120  forms a flange which extends around three sides of the body  112 . If desired, the front face  120  could have an area equal to the area defined by the front of the body (i.e. the face  120  would not define a flange). Alternatively, the front face  120  could form a flange on only two sides of the body or on all four sides of the body. The retainer includes an opening  122  in the front face  120  and an opening  124  on the back surface  126  of the body. The front and back openings  122  and  124  are sized to permit the strap  102  to pass through the retainer  110 . As shown, the back opening is generally oval in shape, and the front opening is generally rectangular. If desired, both openings could be of the same size and shape. Lastly, the retainer includes slots  128  at the back of the top and bottom body surfaces  114  and  116 . As seen in  FIG. 19D , the back surfaces  130 ,  131  of the two slots form an angle □ relative to the back surface of the body. The angle □ is about 5°-10°, and preferably, about 8°. Also, as seen, slots  128  in the top and bottom surfaces are formed such that their respective back surfaces  130  and  131  are co-linear. 
     A wedge  140  is provided with the retainer. As best seen in  FIG. 18B , the wedge  140  is generally trapezoidal in shape, and has two sloped side edges which angle away from each other, such that the top of the wedge is wider than the bottom of the wedge. Preferably, the slope of the wedge side edges corresponds substantially to the slope or angle α of the retainer body slot back walls  130 ,  131 . The wedge  140  has a thickness such that it can be received in the slot  106  of the attachment strap  102 . The wedge has a width at its top greater than the length of the strap slot  106  and a width at its bottom less than the length of the strap slot  106 . 
     To use the attachment assembly  100 , the bracket  67  (or  67 ′) is mounted to the scaffolding upright such that such that the attachment dowel  74  is positioned near the top of a row of blocks of the wall  12  under construction. The strap  102  is passed through the wall  12  as seen in  FIGS. 14-16 . The strap eyelet  104  is passed over the attachment dowel  74 , as seen in FIGS.  18 A,B, and the retainer  110  is slid over the end of the strap  102 , and the front face  120  of the retainer is positioned against the back side of the wall. The strap and retainer are sized such that, when the retainer  110  is slid over the strap, a portion of the strap slot  106  extends beyond the back surface  130 , 131  of the slots  128  while a portion of the strap slot  106  is forward of the retainer body slots  130 ,  131 . With the stand off  72  ( 72 ′) against the retaining wall, as seen in FIG.  18 A,B, the wedge  140  is inserted in the strap slot  106 . As can be appreciated, one side edge of the wedge will engage the end of the strap slot while the other side edge of the wedge  140  will engage the walls  130 ,  131  of the retainer body slots  128 . As the wedge  140  is driven into the slot, the wedge will urge the strap  102  and retainer  110  in opposite directions, such that that the retainer  110  and the bracket standoff  72  ( 72 ′) will be pulled into tight contact with the retaining wall being built. As can be appreciated, the wedge  140  will be frictionally held in place in the strap slot  106  and the retainer body slot  128  and the retaining wall  12  will be tightly sandwiched between the retainer  110  and the bracket standoff  72  ( 72 ′). Hence, the scaffolding upright  116  will be held securely in place relative to the wall  12 . 
     The retainer  110  is designed for use with a closed wall system. An alternative retainer  110 ′ ( FIGS. 20-21 ) is provided to enable the attachment system  100  to be used with an open wall system. As is known, in a closed wall system, the front faces of the blocks are solid, to provide a solid or uninterrupted front surface to the wall. In an open wall system, on the other hand, the blocks  13 ′ are open along their front and back faces, and may even be open along their top surfaces. Hence, blocks  13 ′ can be in the form of a tube or can be generally U-shaped. As is known, an open wall system allows for vegetation to be planted in the openings on the wall. The retainer  110 ′ is in the form of a C-channel having top and bottom surfaces  150  and  152  and a back wall  154 . A slot  156  through which the strap  102  can pass is formed at the bottom of the back wall  154 . The back wall  154  is sized such that the inner surface of the back wall (i.e., the distance from the bottom of the top surface  150  to the top of the bottom surface  152  is greater than the width of the block wall, as seen in  FIG. 21 ). Hence, a gap will be formed between the bottom of the block and the top of the retainer bottom surface  152 . This gap is sized to allow the strap  102  to pass between the block retainer bottom surface and through the retainer slot  156 . The retainer  110 ′ is otherwise used substantially in the same was as the retainer  110 , as described above. 
     After the wall  12  has been constructed, the scaffolding is removed from the wall. As can be appreciated, the straps  102  pass through the wall, and cannot be completely removed from the wall. Rather, the strap is cut off as close as possible to the wall, so that the strap will not be visible. The strap is preferably made from a plastic, to allow for easy cutting of the strap and to provide a strap that will not rust. A metal strap will rust, and the rust will stain the wall  12 . The use of a plastic strap  102  will avoid this. Additionally, the retainers  110  and  150  will be positioned on the back side (or earth side) of the wall, and will also stay with the wall. 
     While the specific embodiments have been described, numerous modifications come to mind without significantly departing from the spirit of the invention, and the scope of protection should only limited by the scope of the accompanying claims. For example, the attachment assembly could be modified to be connected to a positioning projection or key on the wall blocks themselves. In this instance, the strap will not extend through the wall. Rather, the strap will be provided with an opening sized and shaped to be received on the block projection or key. The distance between this block engaging opening and the strap eyelet will be sized such that the bracket standoff  72  ( 72 ′) will contact the wall. The retainer  82  of FIGS.  13 A,B could include a threaded nut which, when threaded onto the threaded end of the rod  78 , urges said retainer  82  against the back surface of the retaining wall  12 . Although the slots  128  of the retainer  110  are shown to be positioned at the back of the retainer, the slots could be positioned between the front and back ends of the retainer. In this instance, the slots would have to have a length greater than the top of the wedge  140  so as not to interfere with the operation of the wedge. Although the gravity pin  46  is preferred to connect the various brackets to the scaffolding uprights, the brackets could be secured in various other ways as well. For example, spring biased pins, straight pins, etc. could be used in lieu of the gravity pins. These examples are merely illustrative.