Patent Grant
9663989
The present invention relates generally to elevated working platforms related methods.
Ladders are one type of apparatus conventionally used to provide a user with improved access to elevated locations that might otherwise be difficult to reach. One of the advantages of ladders is their convenience. Ladders are easily transported from one location to another, generally easy to set up and use at a specific location, and easy to store when not in use. Ladders come in many sizes and configurations, such as straight ladders, extension ladders, stepladders, and combination step and extension ladders. So-called combination ladders may incorporate, in a single ladder, many of the benefits of multiple ladder designs.
In an effort to provide more secure, safe and stable access to elevated locations, users often employ various accessories. For example, planks or other structures are sometimes combined with two or more ladders to act as a platform or scaffolding. In one particular example, so-called ladder jacks are often utilized in conjunction with a pair of ladders to provide a support for one or more wooden planks (e.g., 2 inch×10 inch planks or 2 inch×12 inch planks). Such a configuration enables a user to work on an elevated surface that exhibits a larger support surface area than that of the rung of a ladder and, thus, enables the user to work in a larger area without having to move a ladder multiple times. In another example, an attachment sometimes referred to as a work platform may be coupled to one or more rungs of a ladder in an effort to provide more surface area for the user to stand on, improving their stability and comfort. However, breaking down or disassembling such a configuration, moving all of the components and then setting them up again can be time consuming and require considerable effort. Additionally, there are typically no safety constraints used in such a configuration, making the use of planks a potential safety concern.
It is becoming increasingly common to require users to “tie off” or otherwise secure themselves when using a ladder or other elevating apparatus on a job site. Such a requirement may be instituted by a property owner, by an employer, or by a governmental body such as OSHA (Occupational Safety and Health Administration) to reduce the risk of injury from a fall. However, users of ladders (or other elevated support structures) sometimes find such requirements to be a nuisance and some may even try to avoid such requirements. At a minimum, users of a ladder will typically find that such requirements take additional time, making the worker less efficient at completing their task, even if they are safer while working.
It is also known that many users will often climb higher on a ladder than is recommended for the specific ladder—sometimes to the highest rung of a stepladder or even on the top cap of a stepladder—even though explicit warnings are provided by the manufacturer of the ladder against such behavior. Climbing beyond the highest recommended rung can make the ladder unstable. Additionally, the user may become unstable when climbing beyond a recommended height because, for example, they may not have any additional structure to lean against or grasp with a free hand while standing at or near the very top of the ladder.
As such, the industry is continually looking for ways to improve the experience of using ladders and elevated platforms and to provide the users of such apparatuses with more efficient, effective, safe and comfortable experiences.
In accordance with the present invention, various embodiments of an elevated work platform, as well as associated methods, are provided. The elevated platform may provide a relatively large surface area for a user to stand on while working at an elevated height while also providing a safe working environment without the need to continually tie-off or wear a harness during the use of the apparatus.
In accordance with one embodiment, an elevated platform apparatus is provided comprising a first rail assembly having a pair of rails coupled with a plurality of rungs, a second rail assembly hingedly coupled with the first rail assembly, a platform configured to rest upon a portion of the first rail assembly and the second rails assembly and a cage associated with the platform. The cage includes at least one bar and at least one gate, the at least one gate being configured to swing in a first direction upon a user stepping on to the platform from the first rail assembly, and swing back to a closed position after the user is standing on the platform, the at least one gate also being limited from being displaced in a second direction, opposite the first direction, beyond the closed position.
In one embodiment, the platform is pivotally coupled with the first rail assembly and in selective locking engagement with the second rail assembly.
In one embodiment, the at least one gate includes a pair of gates adjacent one another. Each gate of the pair may include, according to one particular embodiment, a pivoting coupling member having an inclined engagement surface, wherein the inclined engagement surface, in conjunction with the weight of the gate, biases the gate to the closed position.
In one embodiment, the first rail assembly includes an outer rail assembly and an inner rail assembly slidingly coupled with the first rail assembly. One or more adjustment mechanisms may be used to selectively lock the inner rail assembly at a specified location relative to outer rail assembly.
In certain embodiments, a pulley system may be associated with the first assembly. For example, a pulley system may include a tension line having a first, free end and a second end coupled with the outer rail assembly, the tension line being fed through a first pulley coupled to the outer rail assembly and a second pulley coupled with the inner rail assembly.
As with the first rail assembly, according to one embodiment, the second rail assembly includes an outer rail assembly and an inner rail assembly slidingly coupled with the first rail assembly. Again, one or more adjustment mechanisms may be used to selectively lock the inner rail assembly of the second assembly at a specified location relative to outer rail assembly of the second assembly. Another pulley system may be associated with the second assembly.
In one embodiment, a bather member may be positioned on an interior surface of the outer rail assembly at a location adjacent the at least one adjusting mechanism. The barrier member may be configured and located to prevent potential injury to a user's hands or fingers.
In one embodiment, where inner and outer rail assemblies are used, rails of the inner rail assembly are disposed within cross-sectional cavities of associated rails of the outer rail assembly. The rails of the outer rail assembly each include a bracket at their upper end substantially circumscribing the rails of the outer rail assembly as well as the rails of the inner rail assembly, with the bracket defining a slot located along a surface of the rails of the inner rail assembly.
In certain embodiments, at least one pair of wheels coupled with the apparatus. In one specific embodiment the at least one pair of wheels includes: a first pair of wheels coupled with at least one of the first assembly and the second assembly at a fixed location; a second pair of wheels coupled with the first assembly, the second pair of wheels including at least one retraction mechanism; and a third pair of wheels coupled with the second assembly, the third pair of wheels including at least one retraction mechanism. In one embodiment, each of the at least one retraction mechanism associated with the second pair of wheels and the at least one retraction mechanism associated with third pair of wheels includes a cam cylinder, a push rod, a cam follower and at least one biasing member.
In one embodiment, a flexible barrier disposed at least partially about the cage. Such a flexible barrier may include netting or a mesh material. In one particular embodiment, the at least one bar of the cage includes a first bar at a first elevation relative to the platform and a second bar and a second, higher elevation relative to the platform, and the flexible barrier extends between the platform and the first bar and substantially circumscribes the platform except for the location of the pair of gates.
In one particular embodiment, the second assembly includes a pair of rails and a plurality of rungs, and the cage is defined to include at least one additional gate, wherein the at least one additional gate is configured to be displaced from a closed position upon a user stepping on to the platform from the second rail assembly, and return to a closed position after the user is standing on the platform. In certain embodiments, the at least one additional gate includes a pair of gates positioned adjacent to each other.
In accordance with one embodiment, at least one stabilizer coupled with at least one of the first rail assembly and the second rail assembly.
Features, aspects and acts of any of the various embodiments described herein may be combined, without limitation, with other described 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:
Referring to
The apparatus 100 also includes a second assembly 108 that may be configured similarly to the first assembly. For example, the second assembly 108 may include a first pair of spaced apart rails 110A with a plurality of rungs 112A extending between, and coupled to, the spaced apart rails 110A. The first pair of rails 110A and their associated rungs 112A may be referred to as an outer rail assembly. The second assembly 108 may further include a second pair of spaced apart rails 110B and a plurality of rungs 112B extending between, and coupled to, the rails 112B. The second pair of rails 110B and their associated rungs 112B may be referred to as an inner rail assembly. As with the first assembly 102, the inner rail assembly of the second assembly 108 is slidably coupled with the outer rail assembly of the second assembly 108 such that the overall height of the assembly 108 may be selectively adjusted by a user. In some embodiments, rather than rungs 112A and 112B, bracing or other structural components may be used to couple associated rail pairs (110A or 110B) and provide a desired level of support and strength to the spaced apart rails 110 of the second assembly.
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 104A, 104B, 110A and 110B 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 composite materials, plastics, polymers, metals, metal alloys or combinations of such materials. Additionally, in one embodiment, the rungs may be coupled with their associated rails in a manner such as described in U.S. Pat. No. 7,086,499 entitled LIGHT WEIGHT LADDER SYSTEMS AND METHODS, the disclosure of which is incorporated by reference herein in its entirety.
The assemblies 102 and 108 may be coupled to one another by way of a pair of hinges 114 enabling them to extend into a deployed condition (
Adjustment mechanisms 116 may be associated with either or both of the assemblies 102 and 108 to enable elevation or height adjustment of such assemblies. The adjustment mechanism 116 may be similar to that described in the aforementioned U.S. Pat. No. 4,182,431, or it may be of a different configuration. Another example of an adjustment mechanism (such as is depicted in
A platform or deck 120 is associated with the rail assemblies 102 and 108 and may rest on the uppermost rungs, or other associated structure, of the assemblies 102 and 108 when the apparatus 100 is in a deployed condition (see
A safety enclosure, referred to herein as a cage 122, may be formed about the platform to encompass a worker while standing on the platform 120. When designed appropriately, the provision of a cage may preclude the necessity of a worker needing to wear a harness and “tie off” while working on the apparatus. The cage 122 may include a first bar 124 positioned at a first elevation that extends around most (e.g., three sides) of the perimeter of the work space defined by the platform 120. The cage 122 may also include a second bar 126 positioned at a second (higher) elevation that extends around most of the perimeter of the work space defined by the platform 120. One or more gates 128 may be located on one side of the cage 122 and configured to enable a user to climb the first assembly 102 and pass through the gates 128 with the gates 128 closing behind the user as he or she stands on the platform 120. A number of components of the cage 122 may be coupled together using hinges or pivoting joints enabling them to be deployed, as shown in
The gates 128 may be configured, for example, to swing or pivot inwardly as the user pass through them from the rungs 106 of the first assembly 102 to the platform 120, automatically swing back to the position shown in
Referring briefly to
Returning to
Stated another way, the perimeter of the upper portion of the cage 122 (such as may be defined by tracing a path starting at a first end 140 of the upper bar 126, following the upper bar 126 around to its second end 142, and then across the gates 128 back to the first end 140 of the upper bar 126) is larger than the perimeter of the platform 120. Similarly, the area bound by the perimeter of the upper portion of the cage 122 in such an embodiment is larger than the area that is bound by the perimeter of the platform 120.
The upper bar 126 may be pivotally coupled to the extension members 132 extending from the rails 104 of the first assembly 102 above the hinges 114. It is noted that the extension members 132 may be integral with the associated rails 104 (e.g., with the rails 104A of the inner rail assembly), or they may be separate members coupled with the rails through appropriate means. The lower bar 124 may be pivotally coupled to the extension members 132 or it may be coupled to the rails 104 depending on the height of the bar 124 relative to the platform 120.
As may be seen in
Referring to
The apparatus 100 may further include wheels 160 associated with either or both of the assemblies 102 and 108. In one embodiment, as seen in
Feet 170 may be coupled to the bottom of the rails and have appropriate engagement surfaces associated therewith to provide the apparatus 100 with the desired friction and stability when placed on a supporting surface. In one embodiment, the feet 170 may be configured to “snap-on” to the associated rail. For example, the feet 170 (or a combination of the feet and the wheels 160) may be manufactured and assembled as described in U.S. Provisional Patent Application No. 61/445,387 entitled LADDERS, LADDER COMPONENTS AND RELATED METHODS, the disclosure of which is incorporated by reference herein in its entirety.
In another embodiment, retractable wheels 172 may be associated the first assembly 102, the second assembly 108 or both, in place of, or in addition to, the wheels 160 discussed above. For example, as shown in
In one embodiment, each of the retractable wheels 172 (e.g., four, with two being associated with each assembly 102 and 108) may be capable of independent actuation rather that relying on a single mechanism to deploy or retract the set of wheels simultaneously. Such may help to prevent the inadvertent deployment of wheels during use of the apparatus 100, since independent actuation would require a more affirmative act.
Various types of actuating mechanisms may be used for deploying and retracting the wheels 172. For example, in one embodiment, the wheels 172 may be constructed with a biasing element that, when subjected only to the weight of the apparatus 100, enables the wheels to be deployed such that the apparatus may be rolled from one position to another, while, when a user climbs onto the apparatus 100, the additional weight of the user causes the wheels 172 to retract so that the feet 170 engage the ground and stabilize the apparatus 100.
In another embodiment, the retractable wheels 172 may include a cam-follower retraction mechanism similar to what is found in many retractable ball-point pens. For example, referring to
The fins 190 of the push rod 186 are positioned within corresponding slots 180 of the cam sleeve 178 such that the push rod 186 may be axially displaced within the cam sleeve 178 along an longitudinal axis but not rotate within the cam sleeve about the longitudinal axis. The cam follower 192 is configured so that its engagement surfaces 196 engage the undulating engagement surface 188 of the push rod 186 and selectively engage the engagement surfaces 184 of the cam features 182. When not engaged with the engagement surfaces 184 of the cam features 182, the fins 194 of the follower are disposed within the slots 180 so that the follower may be displaced upwardly within the cam sleeve 178.
In operation, a user may lift up on a corner of the apparatus (e.g., so that a foot 170 adjacent the retractable wheel 172 is displaced off of the ground) and push down on the mounting plate 202. Assuming that the mechanism 174 is in a retracted state (i.e., with the wheel or caster displaced upwards), this causes the fins 194 of the cam follower 192 to disengage the slots 180 of the cam sleeve 178 while the undulating surface 188 of the push rod 190 effects a rotation of the cam follower 192 such that when the user removes their foot (i.e., removes application of force to the lower portion of the mechanism 174), the spring 198 pushes the cam follower 192 upwards causing its engagement surfaces 196 to abut the engagement surfaces 184 of the cam features 182. This places the cam follower 192, push rod 186 and, ultimately the wheel 172 or caster in a lower axial position relative to the cam sleeve 178 and housing 178 such that the wheel is “deployed” and may engage the ground instead of the foot 170 that is adjacent the retractable wheel 172. Pushing down on the mounting plate 202 again causes the cam follower 192 to disengage the cam features 182 and enables it to return to its prior axial position with the fins 194 disposed within slots 180 of the cam sleeve 178, placing the wheel in a retracted position. Thus, each retractable wheel 172 may be independently, selectively actuated as noted above. With all of the retractable wheels 172 in a deployed state, the apparatus 100 may be easily wheeled to a new location while maintaining the entire apparatus in a deployed state (i.e., in the state shown in
It is noted that various combinations of actuators or mechanisms may be used and that all of the retractable wheels 172 need not use the same type of mechanism. For example, a mechanism such as shown in
Another feature that may also be included with the apparatus 100 is a stabilizer mechanism. For example, stabilizers or outrigger mechanisms may be associated with the first assembly 102, the second assembly 108, or both, to provide a wider support base and provide greater stability to the apparatus 100. Such stabilizers may also enable the apparatus 100 to be placed in areas having relatively uneven ground wherein the stabilizers adjust to compensate for such unevenness. Referring briefly to
While a single stabilizer 220 is shown in
Referring now to
While the apparatus shown in
In operation, when it is desired to raise an assembly (e.g., 102) to an increased height, a user may actuate the adjustment mechanisms 116 associated with the assembly 102 to enable sliding displacement of the inner rails 104B relative to the outer rails 104A, and then pull the free end of the rope 262 (i.e., apply a tensile force to the rope 262 from the free end). This causes the rope to pull upward on the second pulley 266 causing the inner rails 104B (and associated rungs 106B and other components, including the platform 120 and cage 122 components) to be displaced upward relative to the outer rails 104A. Once at a desired height, the adjustment mechanisms 116 may again be actuated to lock the inner rails 104B relative to the outer rails 104A. A similar process may be used in adjusting the assembly to a lower height by allowing the free end of the rope 262 to slowly be displaced back through the first pulley 264 while keeping the rope 262 relatively taut.
Referring again to
Referring now to
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. Rather, 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 the benefit of U.S. Provisional Patent Application No. 61/589,790 entitled PLATFORM LADDER AND RELATED METHODS, filed on Jan. 23, 2012, the disclosure of which is incorporated by reference herein in its entirety.
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| Number | Date | Country | |
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