The present invention relates generally to ladders and, more particularly, to embodiments of stepladders. Ladders are conventionally utilized to provide a user thereof with improved access to elevated locations that might otherwise be inaccessible. Ladders come in many shapes and sizes, such as straight ladders, straight extension ladders, step ladders, and combination step and extension ladders. So-called combination ladders may incorporate, in a single ladder, many of the benefits of multiple ladder designs.
Ladders known as step ladders, also known as A-frame ladders, are self supporting ladders, meaning that they do not need to be leaned against a wall, pole or other structure for stability. Rather, step ladders may be positioned on a floor (or other similar surface) such that at least three, and conventionally four, feet of the ladder provide a stable support structure for a user to climb upon, even in an open space (e.g., outside or in the middle of a room) without a wall, roof, pole or other type of structure being necessary for the stability of the ladder.
In conventional step ladders, the ladder includes a first rail assembly coupled with a top cap and a second rail assembly coupled with the top cap. One of the rail assemblies conventionally include a plurality of rungs that are evenly spaced between the supporting surface (e.g., the floor or ground) and the top cap. As with all ladders, using a step ladder can present various risks to the user. Often, the risks are amplified when a user utilizes the ladder in a non-recommended manner. There is a continuing desire in the industry to provide ladders that reduce the risk of accident and provide improved safety and stability to a user thereof.
The present invention relates to ladders and, more particularly, various configurations of ladders, as well as to methods relating to the use and manufacture of ladders. In accordance with one embodiment, a step ladder is provided which comprises a first assembly, a second assembly and a top cap coupled with the first and second assemblies. The first assembly comprises a first pair of spaced apart rails and a plurality of rungs extending between and coupled to the first pair of spaced apart rails. The second assembly includes at least one rail. The plurality of rungs of the first assembly exhibit a spacing with a first distance between adjacent rungs and a second distance between the top cap and a rung closest to the top cap, wherein the second distance is at least approximately twice the first distance.
In one embodiment, a lowermost rung of the plurality of rungs exhibits a spacing from a support surface of the ladder that is equal to the first distance.
In one embodiment, the first assembly further comprises a pair of feet, including one foot coupled to each of the first pair of spaced apart rails, wherein the rung closest to the pair of feet exhibits a spacing of the first distance.
In one embodiment, the at least one rail of the second assembly includes a second pair of spaced apart rails.
In one embodiment, the ladder further comprises at least two hinged spreader mechanisms extending between the first assembly and the second assembly.
In one embodiment, at least one of the first assembly and the second assembly is pivotally coupled with the top cap.
In one embodiment, the number of rungs of the plurality of rungs is equal to a nominal height of the ladder in feet minus the integer 2.
In one embodiment, the first distance is approximately 1 foot and the second distance is approximately 2 feet.
In one embodiment, the first assembly and the second assembly are each adjustable in height.
In one embodiment, the first assembly and the second assembly are adjustable in height independent of one another.
In one embodiment, an overall thickness (TTOT) of the ladder when in a folded state is less than a sum of a thickness of the pair of rails of the first assembly (TFR) and a thickness of the at least one rail of the second assembly (TRR). In one particular embodiment, TTOT is approximately equal to TFR. In another particular embodiment, TTOT is approximately 1.5×TFR or less.
In one embodiment, the top cap includes a front wall adjacent the pair of rails of the first assembly, wherein the front wall defines two, spaced apart concave surfaces.
In one embodiment, the rung closest to the top cap exhibits a depth that is greater than the depth of the pair of rails of the first assembly.
In accordance with one embodiment, a step ladder is provided that comprises a first assembly and a second assembly coupled with the first assembly. The first assembly comprises a first pair of spaced apart rails and a plurality of rungs extending between and coupled to the first pair of spaced apart rails. The second assembly includes at least one rail, wherein the at least one rail one rail extends at an acute angle relative to the first pair of rails when the ladder is in a position of intended use. The plurality of rungs exhibit a spacing with a first distance between adjacent rungs and a second distance between an uppermost portion of the step ladder and a rung closest to uppermost portion of the step ladder, wherein the second distance is at least approximately twice the first distance, and wherein the rung closest to the uppermost portion of the step ladder does not contact the second assembly when the ladder is in a deployed state of intended use.
In one embodiment, a lowermost rung, of the plurality of rungs exhibits a spacing from a support surface of the ladder that is equal to the first distance.
In one embodiment, the number of rungs of the plurality of rungs is equal to a nominal height of the ladder in feet minus the integer 2.
In one embodiment, the first distance is approximately 1 foot and the second distance is approximately 2 feet.
In accordance with one embodiment, another step ladder is provided. The step ladder comprises a first assembly, a second assembly and a top cap. The first assembly comprises a first pair of spaced apart rails and a plurality of rungs extending between and coupled to the first pair of spaced apart rails. The second assembly comprises a second pair of spaced apart rails. The first pair of rails are fixedly coupled with the top cap and the second pair of rails are pivotally coupled with the top cap. A lowermost rung of the plurality of rungs is spaced a first distance above a supporting surface when the ladder is in a deployed state of intended use. The plurality of rungs exhibit a vertical spacing between adjacent rungs that is equal to the first distance. An uppermost rung of the plurality of rungs exhibits a vertical spacing from the top cap a second distance which is equal to twice that of the first distance, and wherein the uppermost rung does not contact the second assembly when the ladder is in the deployed state of intended use.
In one embodiment, the first distance is approximately 12 inches.
In one embodiment, an overall thickness (TTOT) of the ladder when in a folded state is less than a sum of a thickness of the pair of rails of the first assembly (TFR) and a thickness of the at least one rail of the second assembly (TRR). In one particular embodiment, TTOT is approximately equal to TFR. In another embodiment, TTOT is approximately 1.5×TFR or less.
In one embodiment, the top cap includes a front wall adjacent the pair of rails of the first assembly, wherein the front wall defines two, spaced apart concave surfaces.
It is noted that the embodiments described herein are not to be considered mutually exclusive of one another and that any feature, aspect or component of one embodiment described herein may be combined with other features, aspects or components of other embodiments.
The foregoing and other advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings in which:
Various embodiments of ladders and ladder components are described herein. The described embodiments are not mutually exclusive of each other. Rather, various features of one described embodiment may be used in conjunction with features of other described embodiments.
Referring to
The stepladder 100 also includes a second assembly 108 having a pair of spaced apart rails 110. In the embodiment shown, a plurality of cross-braces 112 extend between, and are coupled to, the spaced apart rails 110. The cross-braces 112 provide a desired level of strength and rigidity to the second assembly 108, but they are not configured as rungs (i.e., they are not intended to support a user). Thus, the second assembly 108 shown in
The first and second assemblies 102 and 108 may be formed of a variety of materials and using a variety of manufacturing techniques. For example, in one embodiment, the rails 104 and 110 may be formed of a composite material, such as fiberglass, while the rungs and other structural components may be formed of aluminum or an aluminum alloy. In other embodiments, the assemblies 102 and 108 (and their various components) may be formed of other materials including other composites, plastics, polymers, metals and metal alloys.
A top cap 114 is coupled to a portion of the first assembly 102 and a portion of the second assembly. For example, the top cap 114 may be pivotally coupled to an upper end of each rail 110 of the second assembly 108 along a common axis. In one embodiment, the top cap 114 may simply be a structural component configured to facilitate relative coupling of the first and second assemblies 102 and 108. In other embodiments, the top cap 114 may include features that enable it to be used as a tray or a tool holder. Thus, the top cap 114 may be used to organize a user's tools and resources while working on the stepladder 100. For example, such a top cap is described in U.S. Pat. No. 8,186,481 issued May 29, 2012 and entitled LADDERS, LADDER COMPONENTS AND RELATED METHODS, the disclosure of which is incorporated by reference herein in its entirety. The top cap 114 shown in
As with other components of the stepladder 100, the top cap 114 may be formed from a variety of materials. In one embodiment, the top cap 114 may be formed from a plastic material that is molded into a desired size and shape. Of course other materials and manufacturing processes are also contemplated.
The step ladder 100 may additionally include a plurality of feet 116 (one associated with each rail) configured to engage a supporting surface such as the ground. The feet 116 may be configured in a variety of manners based on, for example, the type of environment in which the ladder is anticipated to be used. For example, the feet 116 may be formed of a plastic or polymer material and be configured with a plurality of ridges, knobs or other engagement features configured to provide increased friction between the ladder and a relatively rigid supporting surface (e.g., concrete, tile or wood). Additionally, or alternatively, the feet 116 may include features such as barbs or other sharp protrusions configured to dig into a relatively softer supporting surface (e.g., dirt or grass).
A pair of hinged braces, referred to herein as spreaders 120, are used to maintain a desired angle between the first and second assemblies 102 and 108 when the stepladder 100 is in a deployed or useable state. The hinged nature of such spreaders 120 helps to enable the first and second assemblies 102 and 108 to collapse into a stored state and then help lock the assemblies 102 and 108 in position relative to one another when in a deployed or useable state. It is noted that the spreaders 120 are not configured as rungs or platforms, or otherwise configured to support a user standing thereon. Rather, the spreaders 120 are simply configured to structurally maintain the ladder 100 in a deployed position while enabling the rail assemblies 102 and 108 to be selectively collapsed relative to each other for storage and transportation of the ladder 100.
The rungs 106 of the ladder 100 are configured in a specific manner to minimize potential safety risks to a user of the ladder 100. Using the example of a six foot ladder (i.e., a step ladder having a nominal height of six feet as measured from the feet 116 to the top cap 114 when in a deployed state), four rungs 106 may be provided and spaced relative to one another at a first distance, while the uppermost rung is spaced from the top cap 114 a second distance that is substantially greater than the first distance. In one particular example, the lowermost rung 106 is positioned such that its upper surface is approximately 1 foot from the supporting surface (e.g., the ground), each of the rungs 106 are space approximately 1 foot apart (e.g., from the upper surface of one rung to the upper surface of an adjacent rung), while the upper surface of the uppermost rung is spaced approximately 2 feet from the upper surface of the top cap 114. Thus, there is a substantial space between the uppermost rung 106 and the top cap 114, discouraging and inhibiting a user from climbing on the top cap 114.
Conventional step ladders include an additional rung that would be positioned evenly between the uppermost rung 106 and the top cap 114 of the ladder shown in
It is noted that the uppermost rung of the step ladder 100 shown in
With continued reference to
Thus, in one embodiment, the ladder may be described as having a spacing between the upper most rung and the top cap which is twice the distance exhibited between any two adjacent rungs. In another embodiment, the ladder may be described as having a number of rungs R which is equal to a nominal height H minus 2 (e.g., R=H−2). Thus, for example, in such an embodiment, a 4 foot ladder would have 2 rungs, a 6 foot ladder would have 4 rungs and an 8 foot ladder would have 6 rungs. In another embodiment, a step ladder may be configured so that there is a vertical distance of at least two feet between the upper most rung and the top cap. Again, in such embodiments, the uppermost rung is not configured as a spreader member or as a platform that engages the second assembly, but is only directly coupled with the rails of the one rail assembly (e.g., the first assembly).
As noted above, in some embodiments the ladder may be configured with rungs on both the first assembly and the second assembly. In such an embodiment, the rung spacing of each assembly may be similar, with the uppermost rung being spaced relative to the top cap in a manner such as described above.
It is noted that some prior art ladders have had spacing (which is approved by the American National Standards Institute) that includes a vertical spacing between the support surface (e.g., ground) and the upper surface of the lowermost rung of 6 inches, a vertical spacing between upper surfaces of adjacent rungs of 12 inches, and a vertical spacing between the upper surface of the upper most rung and the top cap of 18 inches (to make up for the short step on to the lowermost rung). However, such a configuration provides a number of concerns, including an awkward transition to the first rung (shorter than anticipated) and a different step height from the first rung to the second rung than a user experiences in going from the ground to the first rung (or vice versa). Additionally, while 18 inches of vertical spacing between the uppermost rung and the top cap is increased over the spacing between adjacent rungs (12 inches), such a distance is not likely to discourage a user from stepping up to the top cap from the uppermost rung. Thus, such a ladder is likely to be awkward in use and may pose some hazards to the user.
Referring now to
Referring to
On the front wall 146 of the top cap 114 (i.e., the portion which corresponds with the first assembly 102 of the ladder(s) 100, 130) is configured with a generally undulating surface, including two, spaced apart concave surfaces 148A and 148B and may be best seen in
Referring briefly to
Referring now to
The stepladder 200 also includes a second assembly 208 having a pair of spaced apart rails 210. In the embodiment shown, a plurality of cross-braces 212 extend between, and are coupled to, the spaced apart rails 210. The cross-braces 212 provide a desired level of strength and rigidity to the second assembly 208, but they are not configured as rungs (i.e., they are not intended to support a user). Additionally, while not specifically numbered in the drawings, it is noted that the ladder may include various bracing and support members (e.g., between rails and rungs) to help provide desired strength and stability.
A top cap 214 is coupled to a portion of the first assembly 202 and a portion of the second assembly 208. For example, the top cap 214 may be fixedly coupled with the upper end of each rail 204 of the first assembly 202 while being pivotally coupled to an upper end of each rail 210 of the second assembly 208 along a common axis.
The step ladder 200 may additionally include a plurality of feet 216 (one associated with each rail) configured to engage a supporting surface such as the ground. The feet 216 may be configured in a variety of manners based on, for example, the type of environment in which the ladder is anticipated to be used.
A pair of spreaders 220 (also referred to as hinged braces), are used to maintain a desired angle between the first and second assemblies 202 and 208 when the stepladder 200 is in a deployed or useable state. The hinged nature of such spreaders 220 helps to enable the first and second assemblies 202 and 208 to collapse into a stored state and then help lock the assemblies 202 and 208 in position relative to one another when in a deployed or useable state. As previously noted, the spreaders 220 are not configured as rungs or platforms, or otherwise configured to support a user standing thereon. Rather, the spreaders 220 are simply configured to structurally maintain the ladder 200 in a deployed position while enabling the rail assemblies 202 and 208 to be selectively collapsed relative to each other for storage and transportation of the ladder 200.
As with previously described embodiments, the various components of the first and second assemblies 202 and 208, the top cap 214, the feet 216 and the spreaders 220 may be formed of a variety of materials and using a variety of manufacturing techniques as will be appreciated by those of ordinary skill in the art.
The ladder 200 exhibits rung spacing similar to that which has been described above with respect to other embodiments. For example, the plurality of rungs 206 are spaced evenly apart (e.g., a vertical spacing of “X”), the upper surface of the lowermost rung being a similar vertical distance of “X” above the supporting structure or ground, and the upper surface of the uppermost rung being spaced a greater distance (e.g., a vertical spacing of “2X”) from the upper surface of the top cap 214. Again, as with other embodiments, fewer or more rungs may be employed and the actual height of the ladder 200 may vary accordingly.
Additionally, the top cap 214 of the ladder 200 is configured so that the rails 210 of the second assembly 208, which are pivotally coupled to the top cap 214, are spaced slightly wider than the rails 204 of the first assembly 202. In one embodiment, the laterally inner surfaces of the rails 210 of the second assembly 208 may exhibit approximately the same width as the laterally outer surfaces of the rails 204 of the first assembly 202 (i.e., they may be only slightly wider so as to avoid interference with the rails 204 of the first assembly 202 when pivoting between the deployed and stored states). To accommodate this difference in width, the top cap 214 may include laterally flared portions 222 to which the rails 210 of the second assembly 208 are attached. Such a configuration enables the ladder 200 to collapse into a stored state (by pivoting the second assembly 208 relative to the top cap 214) such that the two assemblies 202 and 208 fold into a thin profile, with the rear surface of the rails 210 of the second assembly 208 substantially aligning with or becoming nearly coplanar with the rear surface of the rails 204 of the first assembly 202 such as shown in
Other embodiments may also be used to provide a thin profile of the ladder when in a stored state including embodiments where both sets of rails are pivotally coupled with the top cap. Examples of such embodiments are described in U.S. Pat. No. 8,701,831, entitled STEPLADDERS AND RELATED METHODS, filed Mar. 2, 2010, the disclosure of which is incorporated by reference herein in its entirety.
In other embodiments, other types of step ladders may be configured with the rung spacing described herein. For example, an adjustable step ladder, wherein the first and second assemblies are height adjustable, may incorporate such rung spacing. An example of an adjustable step ladder is set forth in U.S. Pat. No. 8,186,481 previously incorporated by reference. Additionally, in some embodiments, the second assembly (e.g., 108) may include only a single rail, rather than a pair of spaced apart rails, if desired. Of course, the specific embodiments described herein are merely examples and a variety of step ladder configurations may be used in conjunction with the present invention.
In yet other embodiments, the ladder may include leveling or stabilizing features. For example, the feet of the ladder may be coupled with leveler mechanisms that enable the ladder to be deployed in an upright, level manner while the support surface (e.g., the ground) is sloping, stepped or otherwise exhibits some degree of elevation change. Some examples of a leveling mechanisms that may be used with the ladder are described in U.S. patent application Ser. No. 14,479,035, entitled ADJUSTABLE LADDERS, LADDER COMPONENTS AND RELATED METHODS, filed Sep. 5, 2014, the disclosure of which is incorporated by reference herein in its entirety.
While the invention may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and have been described in detail herein. However, it should be understood that the invention is not intended to be limited to the particular forms disclosed. Additionally, features of one embodiment may be combined with features of other embodiments without limitation. The invention includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the following appended claims.
This application claims benefit to U.S. Provisional Patent Application No. 62/045,979, filed Sep. 4, 2014, and to U.S. Provisional Patent Application No. 61/883,650, filed Sep. 27, 2013, the disclosures of each of which are incorporated by reference herein in their entireties.
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