The present disclosure relates generally to scaffolding and, more particularly, to a folding utility scaffold.
Folding utility scaffolds are known to collapse into a compact form for storage and shipment. A folding scaffold typically comprises first and second ladder frames with a hinge assembly interconnecting the ladder frames. The hinge assembly enables movement of the scaffold between an unfolded configuration for use and a folded configuration for storage and shipment. Given the rising cost of shipment, there is great interest is designing products generally, and scaffolds in particular, to be more compact in order to reduce shipping costs.
The claimed invention relates to a folding utility scaffold that greatly reduces the space requirement for shipment when the utility scaffold is in the folded configuration. A problem with existing utility scaffolds is that interference between components of the hinge assembly and components of the ladder frame limit the degree to which the scaffold can be collapsed. In embodiments of the present disclosure, the ladder frame and hinge assembly are designed to avoid interference between the components of the hinge assembly and the components of the ladder frame in the folded configuration.
According to an embodiment, the scaffold comprises first and second ladder frames and a hinge assembly interconnecting the ladder frames. The hinge assembly enables movement of the scaffold between an unfolded configuration in which the ladder frames are spaced apart and a folded configuration in which the ladder frames are disposed side by side, i.e., with the ladder frames touching. The ladder frame and hinge assembly are designed to avoid interference between the components of the hinge assembly and the components of the ladder frame in the folded configuration so that the ladder frames can be disposed in side-by-side relation in the folded configuration.
Referring now to the drawings,
The main frame 12 of the utility scaffold 10 comprises two ladder frames 14, two ladder extensions 16, a spreader bar 36 and a hinge assembly 5502. The ladder extensions 26 are inserted into the top end of respective ladder frames 14 and are movable between retracted and extended positions as shown in
The extension members 28 are able slide up and down in the respective vertical supports 16 in a telescoping manner to adjust a height of the ladder extension 26 and spreader bar 42. The ladder extensions are adjustable between a minimum height (shown in
According to one aspect of the disclosure, the ladder extensions 26 can be retracted in the folded configuration so that the overall length in the folded configuration is less than the length in an unfolded configuration. That is, the overall length of the ladder frames 14 with the ladder extensions 26 is less in the folded configuration than a minimum length in the unfolded configuration. Reducing the length of the ladder frames 14 with the extensions 26 reduces the package length for shipping and thus reduces shipping costs.
When a worker is standing on the walkboards 90 spanning between the ladder frames 14, the ladder extension 26 and spreader bar 42 provide a safety rail to prevent the worker from falling off the scaffold 10. The height of the “safety rail” can be adjusted by extending and retracting the ladder extensions as previously described.
As shown in
The hinge 52 comprises an inner hinge part (or first hinge part) 54 and an outer hinge part (or second hinge part) 56. Both the inner hinge part 54 and outer hinge part 56 comprise metal tubes in this embodiment. The inner hinge part 54 is designed to be rotatably received in the outer hinge part 56 and secured by hinge retainers 58 welded to the inner hinge part 54. The inner hinge part 54 is longer than the outer hinge part and projects from both ends of the outer hinge part 56.
Though shown as a single piece in
The first cross braces 60 connect the inner hinge part 54 to a vertical support 16 on a first one of the ladder frames 14 and the second cross braces connect the outer hinge part 56 to a vertical support 16 on a second one of the ladder frames 14. The first cross braces 60 include sleeves 62 that are rotatably journaled on the vertical support 16 of the first ladder frame 14. The second cross braces 64 include sleeves 66 that are rotatably journaled on the vertical support 16 of the first ladder frame 14. The sleeves 62, 66 are secured to the vertical supports 16 of the respective ladder frames 14 by sleeve retainers 68 welded to the vertical supports 16. The location along the length of the vertical supports 16 where the cross braces 60, 64 connect are referred to herein as the connection points.
In conventional utility scaffolds, the cross braces 60, 64 extend horizontally with respect to the ground, i.e., perpendicular to the vertical supports 16, so that the cross braces 60, 64 do not cross the ladder rungs 22 and create interference when the scaffold 10 is collapsed. According to one aspect of the disclosure, the cross braces 60, 64 are angled to increase the distance between the connection points along each vertical support 16 and provide greater stability to the main frame 12 in the unfolded configuration. The location of the connection points are selected so that the cross braces 60, 64 do not cross or interference with the ladder rungs 22 in the folded configuration. In one embodiment, the connection point s for a cross brace with the first and second ladder rungs fall within the same segment of the ladder frames as defined by the ladder rungs. In an alternative embodiment (not shown), the ladder rungs 22 and cross braces 60, 64 could be allowed to cross. In order to avoid interference in this case, the ladder rungs 22 and cross braces 60 are crimped at the crossing point so that they do not interfere in the folded configuration.
The hinge assembly 50 enables the folding of the main frame 12 for storage and/or shipment.
To enable compact packaging, interference between components of the hinge assembly 50 and the components of the ladder frames 14 should be avoided so that the ladder frames 14 can be disposed side by side in the folded configuration. The interference reduction has two aspects. First, interference between the hinge 52 and ladder rungs 22 needs to be avoided so that the hinge 52 does not contact or collide with the ladder rungs 22 in the folded configuration. Second, interference between the cross braces 60, 64 and ladder rungs 22 needs to be avoided so that the cross braces 60, 64 do not contact or collide with the ladder rungs 22 in the folded configuration. Elimination of interference between components of the main frame 12 enables the main frame 12 to be fully collapsed so that the ladder frames 14 make contact in the folded configuration and reduce the space required for storage and shipment.
As previously noted, the offset tongues 24 on the first and second ladder rungs 18 provides a clearance space between the ladder rungs 18. The hinge assembly 50 and clearance space are designed such that the hinge 52 can be received in the clearance space between the ladder rungs 18 in the folded configuration. Also, the length of the cross-braces 60, 64 is designed such that that hinge 52 is received is clearance space in the folded configuration. This means that the spacing between the vertical supports 16 and the hinge 52 is slightly less than the spacing between the two vertical supports on the same ladder frame 14. This design provides two benefits—avoiding interference between the hinge 52 and the ladder rungs 18 and avoiding interference between the cross braces 60, 64 and vertical supports 16 of the ladder frames 14.
Additionally, as previously noted, the arrangement of the cross braces 60, 64 are designed to avoid interference with the ladder rungs 22 when the main frame 12 is folded. In the exemplary embodiment, the lower one of the first and second cross braces 60, 64 (referred to herein as the lower cross branches 60, 64) connect to respective vertical supports 16 below the first ladder rung 22. The lower cross braces 60, 64 also connect to the inner hinge part 54 and outer hinge part 56 respectively at a height below the first ladder rung 22 so that the lower cross braces 60, 64 do not cross or contact the first ladder rungs 22 when the main frame 12 is folded. Similarly, the upper one of the first and second cross braces 60, 64 connect to a respective vertical support 16 between the second and third ladder rungs 22. The upper cross braces 60, 64 also connect to the inner hinge part 54 and outer hinge part 56 respectively at a height between the second and third ladder rungs 22 so that the upper cross braces 60, 64 do not cross or contact the second ladder rung 18 when the main frame 12 is folded.
In one embodiment, the overall length of the base assemblies 70 is greater the width of the ladder frames 14 to provide a wider base for the scaffold 10. Having a wider base allows the scaffold 10 to have a lower stability ration and a greater standing height. The stability ratio is defined as the ratio of the standing height to the base width. A lower stability ratio provides greater safety during use. The base assemblies 70 in the illustrated embodiment provide an increase in the maximum standing height of the scaffold while reducing the stability ratio.
According to an aspect of the present disclosure, the large walkboards 90 are designed to receive the base assemblies 70 when the components of the scaffold 10 are broken down for packaging. The overall height of the base assemblies 70 is less than a width of the walkboards 90 so that the base assemblies 70 fit insider the walkboards 90 for more compact packaging. This feature allows a greater length for the base assemblies 70 than conventional designs so that the maximum standing height can be increased while reducing the stability ratio.
The design of the scaffold 10 enables extremely compact packaging as shown in
The utility scaffold 10 generally comprises a main frame 12, two base assemblies 70 and a set of walkboards 90 of various widths. The main frame 12 is designed to fold into a compact form for shipment and storage. The base assemblies 70 are removable and are designed to fit inside the walkboards 90 when the scaffold 10 is disassembled. The components of the scaffold 10 are designed to fit together so as to occupy as small a space as possible for packaging and shipment.
The main frame 12 of the utility scaffold 10 comprises two ladder frames 14, two ladder extensions 16, a spreader bar 36 and a hinge assembly 50. The ladder extensions 26 are inserted into the top end of respective ladder frames 14 and are movable between retracted and extended positions.
Each ladder frame 14 comprises two vertical supports 16 interconnected by a plurality of ladder rungs 22 welded to the vertical supports 16 as previously described. Selected ladder rungs 22 have crimped ends with offset tongues 24 that are offset from a longitudinal axis of the ladder rung 22. As previously described the offset tongues define a clearance space for hinge 52 (described below) when the utility scaffold 10 is in the folded configuration. This feature allows for more compact folding of the main frame 12
The hinge assembly 50 includes a central hinge 52, first cross braces 60 and second cross braces 64. The hinge assembly 50 is designed to provide greater stability than prior art designs while also allowing the scaffold 10 to fold into a compact form. The hinge 52 comprises an inner hinge part (or first hinge part) 54 and an outer hinge part (or second hinge part) 56. The first cross braces 60 connect the inner hinge part 54 to a vertical support 16 on a first one of the ladder frames 14 and the second cross braces 64 connect the outer hinge part 56 to a vertical support 16 on a second one of the ladder frames 14. The second cross braces 64 include sleeves 66 that are rotatably journaled on the vertical support 16 of the first ladder frame 14. In the folded configuration, the hinge 52 is received in a clearance space defined between the ladder rungs 22 as previously described.
The base assembly 70′ comprises two support posts 74′, a horizontal frame member 72′ connected between the support posts 74′, a pair of spaced apart connectors 80′ for connecting the base assembly 70′ to the ladder frame 14, and a pair of horizontal struts 76′ that connect respective receivers 80 to respective ones of the vertical support posts 74′. The supports posts 74′ are also designed to receive the stem of caster wheels 110 or other ground-engaging members. A generally rectangular gusset plate 78′ connects each vertical support post 74′ to the horizontal frame member 72′ and a respective strut 76′ Each gusset plate 78′ is notched to provide enough free space between the gusset plates 78′ to allow two walkboards 90 and a step 90 to be placed on and engaged with the horizontal frame member 72′. As previously described, the receivers 80′ are spaced such that a distance between the centers of the receivers 80′ equals the distance between the centers of the vertical supports 16 of a ladder frame 14. Each receiver 80 includes an opening 82 formed therein that aligns with the bottom opening 20 of a respective vertical support 16. A span pin is inserted through the aligned openings to secure the base assembly 70′ to the ladder frame 14.
As shown in
The present application is a continuation-in-part of U.S. application Ser. No. 18/096,950, filed Jan. 13, 2023, which claims benefit of U.S. Provisional Application No. 63/301,659, filed on Jan. 21, 2022, the disclosures of each of which are incorporated herein by reference in their entirety.
Number | Date | Country | |
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63301659 | Jan 2022 | US |
Number | Date | Country | |
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Parent | 18096950 | Jan 2023 | US |
Child | 18413138 | US |