Mid-step ladder attachment

Abstract

A ladder attachment device having support frames to which a ladder rung-like standing platform is attached, The support frames are configured to mount onto adjacent ladder rungs, rendering the standing platform vertically midway between them.

Claims

1. An apparatus that attaches to a ladder, of the type formed by laterally-spaced rails connected by vertically-spaced rungs, to provide a step that is positioned vertically midway between two adjacent ladder rungs, the apparatus comprising: a pair of support frames for supporting a standing platform, wherein the support frames are laterally-spaced and each comprises upper, middle and lower portions, wherein the upper portion is defined by an inverted J-shaped receiving recess configured to fit over the adjacent upper rung, the lower portion is defined by an inverted U-shaped receiving recess configured to fit over the adjacent lower rung; and a standing platform for a user to stand upon, wherein the standing platform, at its lateral ends, is attached to the respective middle portions of the support frames, and wherein the standing platform is positioned approximately vertically midway between the adjacent rungs when the upper and lower portions of the attachment are fitted over them. The apparatus of claim 1, wherein each of said support frames is defined by sheet material arranged in a plane normal to the axis of said standing platform, and wherein said upper and lower portion receiving recesses are each configured to be disposed over three sides of a rectangularly tubular ladder rung.

3. The apparatus of claim 1, wherein both of said receiving recesses are rectangular, and wherein the standing surface of said standing platform is along a plane parallel to and approximately equidistant from the planes along which the respective bases of said receiving recesses lie.

4. The apparatus of claim 1, wherein said standing platform is configured such that when said upper and lower portion receiving recesses are fitted over the adjacent ladder rungs, substantially all of the longitudinal width of said standing platform is disposed within a zone of longitudinal width that extends from the inner longitudinal edge of said adjacent upper rung to the outer longitudinal edge of said adjacent lower rung.

5. The apparatus of claim 1, wherein said standing platform is supported by said support frames in a non-cantilever manner.

6. The apparatus of claim 1, herein said standing platform has a frictional standing surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 is a side perspective view of a ladder attachment device in accordance with the present disclosure; and

[0013] FIG. 2 is a top outer perspective view of the attachment device of FIG. 1, the device being shown mounted to a ladder for use as a standing platform.

DETAILED DESCRIPTION OF THE PREFERRED :EMBODIMENTS

[0014] Referring now to FIGS. 1 and 2, there is illustrated a preferred embodiment of the present invention for a mid-step ladder attachment device 1. As shown and as described in its most simple form, the present device is defined by having the following three components: (1) a vertically oriented first support frame element 10 that has an upper portion 16 configured to be placed over a ladder rung, a middle portion 14 and a lower portion configured to be placed over another ladder rung; (2) a second frame element 10 of identical configuration; and (3) a standing platform 30 that extends laterally between and connects the support frames 10.

[0015] The right and left support frames 10 are mirror images of each other. In a preferred embodiment, each support frame 10 is a single piece of rigid sheet material, such as aluminum, steel, an alloy or a hard plastic, that is shaped by a molding or high pressure cutting process (e.g., by a laser jet or water jet cutter). Each frame 10 is comprised of the aforementioned three portions, although, no clear demarcations exist between them. The upper portion 16 is, essentially, an inverted, leaning J-shape that forms an upper receiving recess 26 that, preferably, is rectangular to conformingly fit over three sides of a rectangular cross-sectioned ladder rung 56, as illustrated in FIG. 2. The lower portion 12 is an inverted, leaning U-shape that forms a lower receiving recess 22 that is also rectangular to conformingly fit over the adjacent lower ladder rung 52. The middle portion 14 of each support frame 10 is simply a quadrilateral section to which the standing platform 30 is attached. The support frames 10 lie in vertical planes normal to the horizontal axis of the platform 30.

[0016] Because the support frames 10 are laterally spaced such that their respective upper receiving recesses 26 and lower receiving recesses 22 fit over the lateral near-ends of standard ladder rungs 52, 56 (i.e., close to where the horizontal ladder rungs 52, 56 meet the vertical ladder rails 54), there is, necessarily, an inverse relationship between the lateral thickness of the two support frames 10 and the lateral length of the standing platform 30 that spans between their middle portions 14. By OSHA standards, the space between the rails of a portable ladder must be at least 11.5 inches (29 C.F.R. 1926.1053(a)(4)(ii)). Therefore, so that there are at least slight clearances between the laterally outer faces of the attachment support frames 10 and the rails 54 of the ladder 50 to which it is mounted (as can be gleaned from viewing FIG. 2), the respective outer faces of the support frames 10 should be no more than 10.5 inches apart from each other. Furthermore, the supports 10 should be minimally thick enough to withstand the anticipatable loads to be placed on them without risk of them buckling.

[0017] If the support frames 10 and standing platform 30 are fabricated of metal, the standing platform 30 is a rectangular tube (or of a 3-sided geometry with no tube bottom wall) that is welded, at both of its lateral ends, to the inner faces of the support frames 10. This configuration maximizes the weld joint area to minimize the shear stress experienced at any point, along the platform-frame area of attachment, due to load presented by a user's body weight. If the support frames and standing platform are fabricated of plastic, the standing platform 30 and one of the support frames 10 can be a unitary molded piece, and the other end of the platform can be welded to the other frame 10. In any case, relative to many cantilever-style prior art ladder attachments designed to provide standing support, the present device is more reliably constructed in that those prior art devices experience greater torque and shearing forces due to creation of moment arms when weight is placed upon their standing platforms and, typically, by having smaller areas of load distribution (i.e., the areas of horizontal platform-vertical support attachment). This distinction makes the present apparatus less likely to experience catastrophic failure than many of its prior art counterparts.

[0018] Aside from having a non-cantilever configuration, the attachment 1 has a couple of other characteristics designed to minimize potentially destabilizing torque generation during use. For one, the standing platform 30 is vertically positioned such that its planar, or composite planar, top surface (i.e., the standing surface) 32 forms a plane vertically equidistant from the parallel planes formed by the respective bases of the rectangular-shaped upper and lower rung receiving recesses 26, 22 formed in each support frame 10. For another, the standing platform 30 is longitudinally dimensioned and positioned such that its entire longitudinal width resides within an imaginary zone of width that extends from the vertical plane along which the inner longitudinal edge of the upper ladder rung 56 lies to the parallel plane along which the outer longitudinal edge of the next lower rung 52 lies—and the opposing inner and outer longitudinal edges of the platform 30 are equidistant from those respective inner and outer rung planes.

[0019] Finally, in order to prevent foot slippage, it is preferred that the standing platform 30 have a frictional standing surface 32. For example, a soft rubber corrugated mat can be adhesively bonded to the top surface of the metal or plastic platform 30 to provide such a standing surface

[0020] Aspects of various embodiments of the present invention that are not recited above or claimed below may be noted from observing the illustrations included herein.