Supporting objects on slippery surfaces is usually only reliable if the object applies a vertically downward force on the slippery surface. For example, placement of tall objects, such as poles, boards, and ladders, are often positioned so they lean against a tall stable object, such as a wall or roof. This puts a significant lateral or horizontal force on the foot of the object supported on the surface. If the surface under the object is smooth, the foot of the object tends to slip away from the object it is leaning against.
In particular, falling from ladders is one of the major safety issues in the workplace and particularly in construction. Ideally, ladders are placed on firm, level surfaces that provide a reliable grip for the feet of the ladders. Ladders often get set up on any surface that exists, regardless of whether it is smooth, textured, uneven, or slippery. For example, ladders often get set up on relatively smooth surfaces like waxed floors or artificial decks and don't have safety feet designed to keep them from slipping out from under the worker. Safety experts recommend that If the worker is not able to set up his or her ladder on a firm, level surface, the worker shouldn't set up the ladder at all. However, the exigencies of work and the over-confidence of the worker often leads to ladders being used in less than the safest conditions. Intermediary support bases exist that improve the stability of ladders on various surfaces, but they may still be subject to slippage on particularly smooth, wet, or other slippery surfaces.
The present disclosure provides a slip-resistant support base and method of making and using such a support base. In some embodiments, a slip-resistant support base may include a resilient pad having an exposed lower expanse opposite an upper pad surface, the lower expanse being characterized by a two-dimensional distribution of downwardly open concave recesses having rims forming a lower extremity of the support base. In some examples, the support base includes a body and the resilient pad as a resilient substrate. The body preferably is configured to support an external object positioned on a body upper surface. The resilient substrate is preferably attached to and extends along at least a portion of a body lower surface. The resilient substrate lower expanse is opposite the body lower surface.
In some embodiments, a slip-resistant support base includes a rigid plate, a strap, a barrier, and a resilient substrate. The rigid plate has a plate upper surface and a plate lower surface, the plate being configured to support at least one foot of a ladder positioned on the support base over the plate upper surface. The strap is attached to the plate upper surface and configured to be manually secured to and non-destructively released from a rung of the ladder when the ladder is positioned on the support base. The barrier is fixedly attached to the plate and configured to extend upwardly above the plate upper surface, wherein the barrier is configured to limit movement of the at least one ladder foot along the plate upper surface in at least one direction when the at least one ladder foot is supported on the support base. The resilient substrate is made of a closed cell foam and is attached to and extends along at least a portion of the plate lower surface. The resilient substrate has an exposed lower expanse opposite the plate lower surface produced by shearing off a layer of the closed cell foam. This lower expanse is characterized by a two-dimensional distribution of open concave cut cells facing downwardly, with the cut cells being distributed in a common plane and having a density on the lower expanse of between five cut cells per square inch and fifty cut cells per square inch.
These and other slip-resistant support bases may be formed by shearing off a layer of a pad first major face of a pad of resilient closed cell foam to expose an expanse of cut cells. A pad second major face of the pad opposite the pad first major face may be attached to a plate first major face of a rigid plate. In some examples, a barrier may be attached to a second major face of the plate opposite the plate first major face. The barrier may be configured to limit movement of at least one ladder foot along the plate second major face in at least one direction
Features, functions, and advantages may be achieved independently in various embodiments of the present disclosure, or may be combined in yet other embodiments, further details of which can be seen with reference to the following description and drawings.
Various embodiments of slip-resistant support bases having resilient substrates with exposed downward facing recesses are described below and illustrated in the associated drawings. Unless otherwise specified, such a support base and/or its various components may, but are not required to, contain at least one of the structure, components, functionality, and/or variations described, illustrated, and/or incorporated herein. Furthermore, the structures, components, functionalities, and/or variations described, illustrated, and/or incorporated herein in connection with the present teachings may but are not required to be, included in other support apparatuses. The following description of various embodiments is merely exemplary in nature and is in no way intended to limit the disclosure, its application, or uses. Additionally, the advantages provided by the embodiments, as described below, are illustrative in nature and not all embodiments provide the same advantages or the same degree of advantages.
Generally, a slip-resistant support base preferably may include a body having a body upper surface and a rigid body lower surface wherein the body is configured to support an external object (external to the support base) positioned on the body upper surface. A resilient substrate is attached to and extends along at least a portion of the body lower surface. The resilient substrate has an exposed lower expanse opposite the body lower surface, which lower expanse is characterized by a two-dimensional distribution of downwardly open concave recesses having rims forming a lower extremity of the support base.
Such a support base is particularly useful for maintaining the object in a fixed position relative to a surface, referred to as an external surface such as a building floor, deck, or paved area, on which the support base is placed. This support base is particularly beneficial when the external object applies a lateral or horizontal force to the support base. Such a slip-resistant support base is intended particularly for use as an accessory item that supports the feet of structures, such as extension or other ladders, to reduce slippage on solid surfaces, such as plastic, wood, concrete, composite decks, or other similar floors. It includes the resilient substrate as a lower layer of floor matting structured to temporarily and non-destructively attach to or otherwise grip a floor surface.
Support base 10 is positioned on an external surface 18, such as a floor 20. A ladder 22, as an example of an external object 24, includes side rails 26, 28 having respective bottom feet 30, 32 positioned on support base 10. The ladder includes a plurality of rungs or steps, such as rung 34 extending between the side rails. A user 36 places ladder 22 against a structure (not shown) with feet 30, 32 positioned on a body upper surface 12a. The user may secure support base 10 to the ladder using an optional securement device 16, which is selectively manually securable to the ladder and manually non-destructively removable from the ladder. The user then climbs the ladder as shown.
Optionally, a barrier 38 may be mounted to body 12 to extend upwardly from body upper surface 12a to act in concert with securement device 16 to limit movement of the ladder feet along body upper surface 12a at least in a direction 40. As seen in
In this example, side rail or barrier 38 extends up from the deck (where the ladder feet set) and generally around three sides of the perimeter of the deck. The barrier extends one inch high from support body upper surface 12a and is one inch wide. This rail is formed of urethane molded unitarily with the top layer 46 of the support body 12. This insures the ladder's correct placement and retention on the support base. As mentioned, the barrier includes a section extending from the rear section toward the front midway between the sides. This E-shaped rail adds strength to the base and assures that the weight of the ladder and a user is relatively evenly distributed over the extended surface area of the cut open cells on the bottom of the support base. The rigid plate 44, i.e., board 42 in this example, distributes the pressure from the foot of the ladder over a broad area of resilient substrate 14.
As shown in the figures, support base 10 may be a single piece as shown or it may be made as multiple pieces, i.e., one piece for each support element, such as ladder feet, that are supported, or for each station as defined by barrier 38. In this example of a single-piece construction for use with a conventional ladder having two feet, body 12 as shown in
The MDO board has a smooth bottom or board lower surface 46a also referred to as a rigid plate lower surface 44a and body lower surface 12b, that is suitable for PSA (pressure sensitive adhesive) bonding to the foam rubber pad with the skived open cells exposed, facing away from the MDO board and toward a floor surface during use. Board 42 as plate 44 correspondingly has a board upper surface 42b, which is also plate upper surface 44b. Encapsulant layer 46 correspondingly has a layer upper surface 46a that forms body upper surface 12a and a layer lower surface 46b that is attached to board upper surface 42b. These surfaces are also referred to major faces of the respective layer components.
In this example, resilient substrate 14 has a substrate upper surface 14a attached to body lower surface 12b (plate lower surface 44a, board lower surface 42a) and is in the form of a foam rubber pad made of acrylonitrile butadiene extruded as a 0.5-inch thick foam with a layer, such as the skin, skived off of one side, as is illustrated in
As mentioned, resilient substrate 14 is preferably a closed cell extruded rubber having one major face removed, such as by slicing, cutting, or skiving the skin off of the extrusion. This leaves a continuous resilient-substrate lower surface forming an exposed lower expanse 48 of cut open cells that may function as small, dense suction cups. Other techniques for forming a major face of a resilient material having recesses, such as cavities or other concave structures distributed two-dimensionally along the lower major face of the resilient substrate may also be used.
Preferably rims of the cut cells or other recesses form a lower extremity of the support base, are distributed in two dimensions, and are coplanar along a plane 50. In some examples, the rims and correspondingly recesses have a density on the resilient substrate lower expanse 48 of between five rims or recesses per square inch and fifty rims or recesses per square inch. In some examples, the rims of the recesses have a largest diameter that is less than one-quarter inch. Cell foam producing rims having a largest diameter that is less than one-sixteenth inch have been found to function well on many surfaces, including composite or plastic decking.
There are many different closed cell foams that may be used. Some may work better than others. Skiving foam rubbers is a process that is used to produce foam sheets out of molded or extruded buns that are uniform on each side. Skiving exposes cut cells, creating recesses that are like small suction cups that resist lateral motion along the surface on which the resilient pad is placed. This slip-resistant pad is intended to help reduce the number of accidents involving extension ladders slipping on low-friction decking, such as composite or plastic decking.
Securement device 16 secures support base 10 to ladder 22 or other external object, for ease in relocating the ladder and base during use since they can then be carried as a unit. Securement device 16 may be one of a variety of suitable structures. In this example, the securement device includes an adjustable nylon strap 52 that is attached to the center arm of barrier 38 on body 12 by a fastener 54, such as a screw and washer assembly. One end of strap 52 is attached to a spring clip or buckle 56. During use, the other end is wrapped over the bottom rung 34 of ladder 22 and secured to spring buckle 56 to form a loop, as shown in
In another example, the adjustable strap may be made out of EPDM (ethylene propylenediene monomer (M-class)) rubber. The rubber strap may be 14 inches by 0.75 inches by 0.1875 inches with several holes punched on one inch centers for use on ladders having different spacings below the bottom rungs. This strap may be attached to an open-eye screw hook (such as model Zc 8R) that is screwed into the center rail section at the center of the support base. The strap goes up over the first rung of the ladder and back to the same open-eye screw hook. The screw hook may be three inches long and may be screwed through 1.5 inches of urethane and into 0.5 inches of the MDO (medium density overlay) board. The base may also be secured by a separate securement device associated with each foot of a ladder.
Body 62 also has a rigid body lower surface 62b facing resilient substrate 64. In this example, body 62 is a rigid plate 72 having a corresponding plate upper surface 72a and a plate lower surface 72b preferably with the plate having dimensions of 23.75 inches by 11.75 inches. Plate 72 may be made of a suitable metal, such as 12 gauge aluminum. Other materials that provide a sufficiently strong and rigid plate may be used. Plate 72 is sufficiently rigid to distribute load forces over an area of resilient substrate 64 broader than the footprint of the object (ladder foot) supported on plate upper surface 72a.
Resilient substrate 64 may be the same as resilient substrate 14 described above with reference to support base 10. The description of resilient substrate 14 thus applies to resilient substrate 64. Accordingly, resilient substrate 64 includes a lower expanse 74 having downwardly facing recesses and has a substrate upper surface 64a attached to body lower surface 62b (plate lower surface 72b).
Barrier 68 is preferably made of 2.5 inch high 12-gauge aluminum flat bar that is stitched or welded to the upper surface of plate 72. Preferably, barrier 68 extends 21 inches along the rear portion of plate 72 (as viewed in
Securement device 66 may be the same as securement device 16, and may include a strap 76, a spring latch 78, and a fastener 80. Since plate 72 is made of comparatively thin sheet of aluminum, fastener 80 is preferably an elevator or carriage bolt extending upwardly through a square hole with a nut and washer securing the strap to plate 72.
In both or either of support bases 10 and 60, the resilient substrates are preferably attached to the body or plate with pressure sensitive adhesive, which is applied to the substrate upper surface opposite the lower expanse of the face having recesses. This allows the resilient substrate to be removed and replaced. During use, if the pad begins to loose resiliency or is otherwise damaged, it can be peeled off of the body or rigid plate and a new pad attached.
As shown in
It will be appreciated from the above description that a slip-resistant support base includes a resilient pad having an exposed lower expanse opposite an upper pad surface, the lower expanse being characterized by a two-dimensional distribution of downwardly open concave recesses having rims forming a lower extremity of the support base. In some examples, the support base includes a body and the resilient pad as a resilient substrate. The body preferably is configured to support an external object positioned on a body upper surface. The resilient substrate is preferably attached to and extends along at least a portion of a body lower surface. The resilient substrate lower expanse is opposite the body lower surface.
The rims are preferably distributed in a common plane. The resilient pad or substrate may be a closed cell foam. The lower expanse may be produced by shearing off a layer of the closed cell foam. The body preferably includes a rigid plate having a lower face extending along the body lower surface. The lower face of the rigid plate preferably forms the body lower surface. In some examples, the resilient substrate is manually removable from the body lower surface without damaging the body lower surface. For example, the resilient substrate may be attached to the body lower surface by a pressure-sensitive adhesive.
The rims of the recesses preferably have a density on the resilient substrate lower expanse of between five rims per square inch and fifty rims per square inch. The rims of the recesses may have a largest diameter that is less than one-quarter inch, or more preferably is less than one-sixteenth inch.
A securement device may be secured to the body upper surface and configured to be secured to the external object. Such a securement device is preferably configured to be manually secured to and non-destructively released from the external object.
In some examples, then, a slip-resistant support base includes a rigid plate, a strap, a barrier, and a resilient substrate. The rigid plate has a plate upper surface and a plate lower surface, the plate being configured to support at least one foot of a ladder positioned on the support base over the plate upper surface. The strap is attached to the plate upper surface and configured to be manually secured to and non-destructively released from a rung of the ladder when the ladder is positioned on the support base. The barrier is fixedly attached to the plate and configured to extend upwardly above the plate upper surface, wherein the barrier is configured to limit movement of the at least one ladder foot along the plate upper surface in at least one direction when the at least one ladder foot is supported on the support base. The resilient substrate is made of a closed cell foam and is attached to and extends along at least a portion of the plate lower surface. The resilient substrate has an exposed lower expanse opposite the plate lower surface produced by shearing off a layer of the closed cell foam. This lower expanse is characterized by a two-dimensional distribution of open concave cut cells facing downwardly, with the cut cells being distributed in a common plane and having a density on the lower expanse of between five cut cells per square inch and fifty cut cells per square inch.
These and other slip-resistant support bases may be formed by shearing off a layer of a pad first major face of a pad of resilient closed cell foam to expose an expanse of cut cells. A pad second major face of the pad opposite the pad first major face may be attached to a plate first major face of a rigid plate. In some examples, a barrier may be attached to a second major face of the plate opposite the plate first major face. The barrier may be configured to limit movement of at least one ladder foot along the plate second major face in at least one direction when the at least one ladder foot is supported on the support base over the plate second major face when the support base is placed on an external surface with the expanse of cut cells in contact with the external surface.
Shearing off the layer of the pad first major face of the pad of closed cell foam may include shearing off the layer of the pad first major face of the pad of closed cell foam along a plane. Attaching the pad second major face of the pad to the plate first major face of the rigid plate may include attaching the pad second major face of the pad to the plate first major face of the rigid plate with a pressure sensitive adhesive. The pad of closed cell foam may be selected so that the exposed expanse of cut cells has a density of between five cut cells per square inch and fifty cut cells per square inch. The A strap may be secured to the plate second major face, which strap is configured to be manually secured to and non-destructively released from a rung of the ladder when the ladder is supported on the plate second major face.
Extension ladders in typical use are found to not slip when placed on a support base having the exposed expanse of a cut closed-cell foam extrusion. In other embodiments, such a resilient pad with distributed exposed cavities may be built into the feet of ladders, or may be separate bases with one for each ladder foot. Smaller individual foot versions provide improved traction over the more rigid plastic feet of conventional ladders. However, the reduced surface area may have diminishing effectiveness with increased weight and duration of use. The bases illustrated in the figures use a rigid planar plate on the resilient pad to distribute the weight applied by the ladder to a greater pad surface area. Thus, the illustrated bases, having a one piece structure, spread the forces applied by the ladder or other object over a greater area than support bases having smaller footprints. This increases the overall ability of the support base to resist movement along the working surface while reducing the overall force per square inch applied to the resilient substrate. The resilient pad has a further benefit of protecting attractive floors from the scuffing that ladders create on composite decks as well as on finished floors found in gymnasiums, shopping malls, and other facilities.
The slip-resistant pad as shown is a solution to a well known problem of extension ladders slipping when used on decks. This problem has been exacerbated with the popularity of composite (plastic) decking. Also increasing this problem is the environmental effort to build buildings higher, thereby increasing the use of extension ladders. Accidents on extension ladders are seldom minor.
The disclosure set forth above may encompass multiple distinct inventions with independent utility. Although each of these inventions has been disclosed in its preferred form(s), the specific embodiments thereof as disclosed and illustrated herein are not to be considered in a limiting sense, because numerous variations are possible. The subject matter of the invention(s) includes all novel and nonobvious combinations and subcombinations of the various elements, features, functions, and/or properties disclosed herein. The following claims particularly point out certain combinations and subcombinations regarded as novel and nonobvious. Invention(s) embodied in other combinations and subcombinations of features, functions, elements, and/or properties may be claimed in applications claiming priority from this or a related application. Such claims, whether directed to a different invention or to the same invention, and whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the invention(s) of the present disclosure.
Where “a” or “a first” element or the equivalent thereof is recited, such usage includes one or more such elements, neither requiring nor excluding two or more such elements. Further, ordinal indicators, such as first, second, or third, for identified elements are used to distinguish between the elements in the order in which they are introduced, and do not indicate a required or limited number of such elements, and do not indicate a particular position or order of such elements unless otherwise specifically indicated. Accordingly, the ordinal indicator used for a particular element may vary in different contexts.
This application claims the benefit of U.S. Provisional Application No. 62/459,781, filed Feb. 16, 2017, titled Slip-Resistant Support Base, which provisional application is incorporated herein by reference in its entirety for all purposes.
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Number | Date | Country | |
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62459781 | Feb 2017 | US |