BACKGROUND
Ladders have the problem that when in use, they are generally unstable. This lack of stability will often lead to injury or even death. Indeed, injuries related to ladder use are a leading problem in construction, repair and other industries. Until now, the most common way to remedy an unstable ladder is to require a second person to be positioned at the base of the ladder, or to construct a form of scaffolding, which is both costly and time-consuming.
Accordingly, there is a need for a collapsible multi-surface, self-supporting ladder with an increased stability that does not require a second person or unnecessary assembly time. One aspect of the present disclosure is to provide a configuration that will help prevent injuries for an individuals who is climb, work on, dismount from, or do any other work with a ladder. It is contemplated that the exemplary embodiments disclosed below can be used on, inter alia, an extension ladder, pull-down attic ladder, one-piece straight ladder or any other ladder where additional stability is needed.
SUMMARY
According to one exemplary embodiment, the collapsible ladder assembly system includes a larger ladder section and a smaller strut section, wherein the smaller strut ends are pivotally connected to the larger ladder section at a point that is at or below the midpoint of the larger ladder section, therefore allowing the system to be collapsible. The larger ladder section and smaller strut section are further connected by a rigid adjustable linkage, or spreader, at points that are below the pivotable connection that are capable of adding further stability and maintaining a consistent predetermined angle or distance between the feet of the larger ladder and the smaller strut section.
According to another exemplary embodiment, the collapsible ladder assembly system includes a pre-existing larger ladder section and a smaller strut section, wherein the smaller strut ends are detachably and pivotally connected to the pre-existing larger ladder section at a point that is at or below the midpoint of the larger ladder section, therefore allowing the system to be collapsible and/or detachable. The larger ladder and smaller strut sections are connected by a rigid adjustable linkage, or spreader, at points that are below the pivotable connection. These linkage connections can be detachable at the pre-existing large ladder end and permanent at the smaller strut section, or a variation thereof.
The exemplary ladder configurations disclosed herein provide a means for stability on multiple surfaces. At the ground contacting point, the point where the rail or strut ends meet the ground, there are adjustable gripping feet or shoes, which can be independently or in combination vertically or angularly adjusted for maximum stability.
According to a first aspect of the present invention, an apparatus for stabilizing a ladder is taught. The apparatus comprising two or more substantially parallel support rails each having a first end and a second end; one or more longitudal cross members connecting said substantially parallel support rails; a pivotable connector for adjoining the first end of each substantially parallel support rail to a ladder rail; a spreader having a first end and a second end wherein the first end is connected to a support rail and the second end for connecting to a corresponding ladder rail; and an adjustable shaft at the second end of each support rail.
According to a second aspect of the present invention, an apparatus for stabilizing a ladder is taught. The apparatus comprising two or more substantially parallel support rails each having a first end and a second end wherein the second ends are flared outward; one or more longitudal cross members connecting said substantially parallel support rails; a pivotable connector for adjoining the first end of each substantially parallel support rail to a ladder rail; a spreader having a first end and a second end wherein the first end is connected to a support rail and the second end for connecting to a corresponding ladder rail; and an adjustable shaft at the second end of each support rail.
According to another aspect of the present invention, the apparatus may further included support rails that include a bend at a point between the first end and a midpoint which is approximately half way between the first and second ends.
DESCRIPTION OF THE DRAWINGS
These and other advantages of the present invention will be readily understood with reference to the following specification and attached drawing wherein:
FIG. 1 is a front angular perspective view of a first embodiment of a ladder system of the present invention mounted on a pull-down ladder in the collapsed position;
FIG. 2 is a front angular perspective view of the first embodiment of a ladder system of the present invention mounted on a pull-down attic ladder in the extended position;
FIG. 2A is an exploded view of the adjustable spreader of the ladder system in FIG. 2;
FIG. 2B is an exploded view of the adjustable foot of the ladder system in FIG. 2;
FIG. 3 is a side angular perspective view of a second embodiment of the adjustable ladder system of the present invention mounted on an extension ladder;
FIG. 3A is an exploded view of the adjustable spreader of the ladder system in FIG. 3;
FIG. 3B is an exploded view of the adjustable foot of the ladder system in FIG. 3;
FIG. 4 is a side angular perspective view of a second embodiment of the adjustable ladder system of the present invention mounted on an extension ladder set up to allow for a greater ground foot-print;
FIG. 4A is an exploded view of the adjustable spreader of the ladder system in FIG. 4;
FIG. 4B is an exploded view of the adjustable foot of the ladder system in FIG. 4;
FIG. 5 is a side angular perspective view of a second embodiment of the adjustable ladder system of the present invention mounted on an extension ladder set up to allow for a maximum ground foot-print;
FIG. 5A is an exploded view of the fully extended adjustable spreader of the ladder system in FIG. 5;
FIG. 5B is an exploded view of the adjustable foot of the ladder system in FIG. 5;
FIG. 6 is an exploded view of a partially extended adjustable spreader of the ladder system;
FIG. 7 is a side view of the ladder system showing the spreader in a locked extended position;
FIG. 8 shows an alternative foot with a rubber boot;
FIG. 9 shows an alternative foot where the shaft forms a spike;
FIG. 10 shows the safety latch mechanism;
FIG. 11 is a side view of the ladder system with a spring-loaded adjustable foot where the fixed spreader is in a locked extended position; and
FIGS. 12A-D are exploded views of the operation of the spring-loaded adjustable foot of the ladder system of FIG. 11.
DETAILED DESCRIPTION
Referring to FIG. 1, an embodiment of the ladder system 20 mounted to pull-down ladder 10 in a partially collapsed state is depicted. The ladder system 20, or smaller strut section, includes a pair of rails 22, 24 substantially identical but of opposite hand, a lateral cross member strut 26, a pair of adjustable feet 28, 30 substantially identical but of opposite hand, and a pair of rigid adjustable spreaders 32, 34 substantially identical but of opposite hand.
Referring now to FIG. 2, the ladder system of FIG. 1 is shown fully extended. In this embodiment, the rails 22, 24 are substantially parallel, however in an alternative embodiment the rails 22, 24 may be outwardly flared at their lower ends to create a wider stance, allowing for increased stability. In either embodiment, each of the rails 22, 24 has a foot 28, 30 located at the end of the rail 22, 24 where contact is made with the ground, referred to as the ground contacting point, while the opposite end of each of the rail 22, 24 is pivotally connected, using pivotal connectors 36, 38, to its respective rails 40, 42 of the pull-down ladder 10. The pivotal connections 36, 38 can be either permanently connected by means of a bolt, rivet, pivoting hinge, etc., or alternatively, the pivotal connection can be removably attached to the rails 40, 42 of the pull-down ladder 10 by means of a clamping structure, allowing the ladder system to be used on a multitude of preexisting ladders.
Referring to FIG. 2A, an exploded view of an adjustable spreader of the ladder system, the depicted rigid adjustable spreader 32, 34 is generally composed of two rigid spans 32a, 32b that are pivotally connected at their ends with a shank 33a and lock pin 33b such that the two rigid spans 32a, 32b can lock in the fully extended position to form a spreader between the rails 22, 24 in the lower section, between the midpoint of the ladder rail length and the ground contact points, of their respective rails 40, 42 of the pull-down ladder 10. In other embodiments, an extension ladder or step-to-straight ladder may be stabilized in lieu of a pull-down ladder. For example, when applied to a 28 foot extension ladder, the rigid span, or spreader, is connected to the existing ladder approximately 17 inches (nearly 1/20th the total length of the ladder) off the ground. The pivotal connection may be laterally adjustable such that the length of the spreader can be increased or decreased thereby increasing or decreasing the angle created between the ladder system rails 22, 24 and their respective rails 40, 42 of the pull-down ladder 10. In certain embodiments, as seen in FIG. 11, the spreader may a standard spreader 62 with a fixed length S as used in a traditional step ladders. The length S of the fixed spreader is determined based on the total length L of ladder being stabilized and the desired base or foot-print size. For example, in a preferred embodiment using a standard spreader 62, the spreader's 62 total length S, when applied to a 28-foot extension ladder, may be approximately 24 inches. The approximately 24-inch spreader may however be used for a range of ladder sizes (e.g. 24 to 40 foot extension ladders). For smaller ladders (e.g. a 16-foot extension or step-to-straight ladder) a spreader length S of approximately 18 to 19 inches would be preferred. Naturally, various spreader lengths S may be used depending on the application and length L of the ladder (e.g. a longer spreader may be used for longer ladders which may require a larger foot-print or base). As seen in the figures, the rails 22, 24 may be predrilled with more than one set of holes near the shaft 44 so that a single fixed length spreader 62 may be used with a number of ladders lengths and sizes by simply installing the spreader 62 at different locations on the rails 22, 24.
Referring to FIG. 7, another means for connecting two rigid spans 32a, 32b is shown. The two rigid spans 32a, 32b are connected to one another at two points, there is a permanent laterally slideable connection and a second connection that locks the span at the specified length using the safety stop 84 and a pin 33A that penetrates the hole of the safety stop 84 and the desired hole in the rigid span 32b therefore locking the overall length of the spreaders 32, 34. When the pin 33A is not in the safety stop 84, the spreader can be folded at the slideable connection. To prevent misplacement, the pin 33A may be tethered to the ladder or ladder system 20. In an alternative embodiment, there may be more than 2 rigid spans comprising the spreader, and the connection between the at least two rigid spans can be by another means, including but not limited to a threaded post and wing nut or screw caps 50.
Referring to FIG. 2B, an exploded view of a ladder system foot 28 is shown. The feet 28, 30, located at the end of the rails 22, 24 at the ground contact point, are both angularly and vertically adjustable. Each of said feet 28, 30 is composed of two primary components, a vertically extendable shaft 44 and shoe 46 pivotally connected to the shaft 44 using a pivotal connector 48. The pivotal connector 48 allows the shoe 46 to conform to angle of the ground on which it is placed. If required, the pivotal connector 48 can be tightened, therefore locking the shoe 46 in the preferred arrangement. The length of the rails 22, 24 depends on the application of the ladder system. When stabilizing a shorter ladder, the rails 22, 24 may be shorter than rails 22, 24 being used to stabilize a longer ladder, or when a larger foot-print or base is needed for stabilizing a ladder. For example, when a ladder having a length L of 6 to 23 feet (e.g. a 16 foot extension ladder or step-straight ladder) is used, the rails 22, 24 may be approximately 21 inches in length K from the foot-end to the bent portion 64 of the rails 22, 24. Similarly, when a ladder having a length L of 24 to 40 feet (e.g. a 28-foot extension ladder) is used, the rails 22, 24 may be approximately 30 inches in length K from the foot-end to the bent portion of the rails 22, 24. Naturally, the length K of the rails 22, 24 may vary from the provided measurements.
The underside of the shoe 46 includes a gripping material to minimize slippage at the ground contact point. Depending on the application, said gripping material could be a rubber pad for use on a relatively smooth hard surface, spiked (as seen in FIG. 9) or staggered for use on grass and packed dirt, or even a planar foot that creates a large shoe surface area, therefore preventing the foot 28, 30 from sinking into soft ground. Depending on the choice of shoe 46, the ladder system 20 can be used on ground surfaces such as concrete, dirt, steel, tile, grating, brick, stone and most floor materials. The pivotable connector 48 between the shaft 44 and shoe 46 may be permanent or removable, therefore allowing one to interchange the shoe 46 depending on the application or environment.
Alternative foot embodiments are shown in FIG. 7 wherein the shoe 46 is directly coupled to the end of the rails 22, 24 and FIG. 8 wherein the shaft 44 comes into direct contact with the ground or through an optional intermediate such as a rubber boot 80. The rubber boot 80 acts as a gripping material and prevents the shaft 44 from scratching the ground. Referring now to FIG. 9, in lieu of a rubber boot 80, the end of the shaft 44 may be pointed to increase ground penetration, therefore preventing slippage on dense penetratable surfaces such as dirt, grass, gravel and rock.
Referring now to FIGS. 3-5, in this embodiment, a side view of the ladder system's versatility is shown when the ladder system 20 in installed on a traditional straight ladder 60; however, the system is not restricted to a straight ladder but can be applied to any ladder where additional stability is required. FIGS. 3-5 show three adjustment configurations where the rigid adjustable spreaders 32, 34 have been laterally adjusted to create a larger overall foot-print by increasing the distance between the larger ladder section 60 and the ladder system 20, the shaft 44 is vertically adjusted to ensure that steady contact between the shoe 46 and the ground is maintained, and the shoe 46 adapts to the angle and terrain of the ground. The shaft 44 as shown in FIGS. 3B, 4B and 5B is adjusted using two nested tubes 56, 58 with a plurality of holes 52 which, when adjusted to the appropriate height, can be aligned and locked into place using a set pin 54. In alternative embodiments, a push-button adjustment mechanism with or without a locking ring may be used to secure the two nested tubes 56, 58, the nested tubes 56, 58 may be locked at a specified length with a slip nut and washer, or the two nested tubes 56, 58 may be threadedly coupled wherein the overall shaft 44 is extended or shortened by rotating the shoe 46 and/or lower nested tube 56. In another embodiment, as depicted in FIGS. 12A-12D, the nested tubes 56, 58 may be spring-loaded. This may accomplished, for example, using a spring 68 and series of notches 70, or grooves, to quickly and safely adjust the height of the shaft. The upper nested tube 58 includes a series of angled notches 70 configured to receive one or more pegs 72. The lower nested tube 56 would include one or more pegs 72 which may be received by the angled notches 70 in the upper nested tube 58. A spring 68 is housed in the hollow space within the nested tubes 56, 58 and creates a constant force pulling the tube ends toward each one another in direction B, therefore shortening the shaft 44. To make adjustments to the shaft's 44 length, a user would twist the foot 46 and/or lower nested tube 56 in direction C so that the one or more pegs 72 is withdrawn from one or more angled notches 70. The user may then pull the foot 46 and/or lower nested tube 56 in direct A until the desired shaft 44 length has been reached. Once the desired length has been reached, the user twists the foot 46 and/or lower nested tube 56 in direction D causing the one or more pegs 72 to be inserted into the one or more angled grooves 70. The tension created by the spring 68 pulls nested tube 56 in direction B and securely holds the one or more pegs 72 in the one or more angled grooves 70. When weight is applied to the ladder or shaft 44, a force is created in direction B that further secures the one or more pegs 72 in the one or more angled grooves 70 to prevent collapsing and/or shortening of the shaft 44.
As seen in FIGS. 1-5 and 11, each of the rails 22, 24 includes a bend 64, 66 near the point where the rails 22, 24 are connected to ladder rails 40, 42. The bends 64, 66 allow for the ladder system 20 to lay flush, or substantially parallel to the existing ladder, when in a closed position. In a preferred embodiment, the bends 64, 66 in rails 22, 24 are approximately 45 degrees off the rails' 22, 24 center line. The length and angle of the bent portion may however be adjusted based on the application, length and shape of the ladder system 20 or rails 22, 24. Referring to FIG. 10, the ladder system may be locked in the closed position using the safety latch 82 which locks the ladder system 20 to ladder being stabilize. The safety latch can be used with a plurality of ladders, including but not limited to pull-down ladders, straight ladders and extension ladders. FIG. 10 shows the safety latch 82 attached to the lateral cross member strut 26, however in another embodiment, the safety latch 82 may attach to a loop or other latch receptacle.
The ladder system 20 structure as described can be constructed from any material known in the art of ladder fabrication, including but not limited to wood, metal, metal alloys, fiberglass, composites, carbon fiber, plastic or a combination thereof. Similarly, the rails of the smaller strut section, or ladder system 20 need not be the same material as the larger ladder section. The ladder system 20 may also include a kick peg 74 mounted on one or both of the ladder system rails 22, 24 or other stable ladder system 20 surface. The kick peg 74 allows for easy employment of the ladder system because the user is able to spread the ladder system away from the existing ladder using only a foot.
Obviously, many modifications and variations of the present invention are possible in light of the above teachings. Thus, it is to be understood that the invention may be practiced otherwise than as specifically described above.
Patent Application
20110017548
