Apparatus for stabilizing a ladder during use and stepladder incorporating the same

Abstract

An apparatus for stabilizing a stepladder and a stepladder incorporating the same. In one aspect, the invention is an apparatus for stabilizing a ladder on a ground surface comprising: a first plate adapted to be secured to a leg of the ladder; a second plate having a top surface and a bottom surface, the second plate pivotally connected to the first plate and pivotal between a retracted position where the second plate does not substantially contact the ground surface and a stabilizing position where the bottom surface of the second plate is in contact with the ground surface; a member having a proximal end pivotally connected to the first plate and a distal end, the member pivotal between a substantially upright position and a support position where the distal end of the member is in contact with the top of the surface of the second plate when the second plate is in the stabilizing position. In another aspect, the first plate is not used and the member and second plate are connected directly to the stepladder.

Description

FIELD OF THE INVENTION

The present invention relates generally to the field of ladders, and specifically to apparatus for increasing the stability of ladders and improved stepladders incorporating the same.

BACKGROUND OF THE INVENTION

Although ladders are not rated high on the Consumer Product Safety Commission list of hazardous products, use of ladders has always entailed the danger of falling off of the ladders due to the side-ways tipping of the ladder. This is because the combination of a ladder and an individual standing on the ladder has a high center of gravity relative to the width of the ladder base. With stepladders, a prominent hazard is lack of lateral stability so that when a climber on the ladder reaches outward to perform a task or push laterally, the ladder may not resist both static and dynamic loading or shifting weight thereby resulting in a tilting accident. Thus, there is a need to improve upon their construction to diminish these hazards to users.

It has been established that a primary element in stepladder stability is the total width of the ladder base. Another factor is the climbing height for any particular ladder size. Hence, stepladder stability can be improved by increasing the width of the base of a ladder, as opposed to adding to the length of its steps.

The prior art is replete with attempts to maximize the stability of ladders. One such attempt involves the appending to a ladder of adjustable outrigger arms to provide the ladder with an effectively wider base. Examples of attempts can be found in U.S. Pat. Nos. 2,997,127, 3,878,917, 4,011,926, 4,175,641, 4,433,754, 4,519,477, 4,625,832, 4,641,729, 4,872,529, and 5,086,876. The problem with these prior art attempts is that they provide devices which tend to be cumbersome, limited, awkward, complex, and difficult and/or time consuming to manufacture. Moreover, prior art devices only increase the base of the ladder in a single direction, such as width (i.e. side to side), and do not provide added stability in the forward or backward directions. There is therefore a need for a ladder stabilizing apparatus that is light, non-cumbersome, simple in construction, versatile, quick and easy to manufacture and attach to a ladder, and provides added stability in more than one linear direction.

SUMMARY OF THE INVENTION

The present invention satisfies these and other needs. In one aspect, the invention is an apparatus for stabilizing a ladder on a ground surface comprising: a first plate adapted to be secured to a leg of the ladder; a second plate having a top surface and a bottom surface, the second plate pivotally connected to the first plate and pivotal between a retracted position where the second plate does not substantially contact the ground surface and a stabilizing position where the bottom surface of the second plate is in contact with the ground surface; a member having a proximal end pivotally connected to the first plate and a distal end, the member pivotal between a substantially upright position and a support position where the distal end of the member is in contact with the top of the surface of the second plate when the second plate is in the stabilizing position.

When the second plate is in the stabilizing position and the member is in the support position, the base of the ladder to which the apparatus is attached is effectively increased in size. The second plate can be sized so that when it is in the stabilizing position, both the width and length of the perimeter of the ladder base is increased. By not connecting the distal end of the member to the second plate, both the member and the second plate can be moved to a retractable position for easy storage. Ease of use and storage is also increased by the member being preferably designed to be less than 12 inches in length. However, stability is not compromised by having a short member for support because the increase in the size of the base dictated by the size of the second plate, not the length of the member as with prior art devices.

In order to ensure that the distal end does not slide with respect to the top surface of the second plate, the distal end of the member preferably has a rubber stop provided at its end for contacting the top surface of the second plate when the member is in the support position and the second plate is in the stabilizing position. Optionally, any means to prohibit sliding can be used, such as a groove or ridge formed into or on the second plate.

The first plate preferably comprises mounting brackets extending outward from the first plate for pivotally connecting the proximal end of the member. The first plate can be rigidly secured to the leg of the ladder by a plurality of bolts or other fasteners. The member pivots between the substantially upright position and the support position about a first axis. The second plate pivots between the retracted position and the stabilizing position about a second axis. It is further preferable that these first and second axes be substantially parallel.

When the apparatus is properly secured to the leg of the ladder and the second plate is in the stabilizing position, the second plate will preferably be substantially horizontal and flush with a bottom surface of the leg of the ladder.

In another aspect, the invention is a stepladder incorporating the above apparatus on at least one of its legs. More specifically, in this aspect, the invention is a stepladder having high stability comprising: a plurality of legs in contact with a ground surface; and a stabilizing assembly having a first plate secured to an outer surface of at least one of the legs, a second plate having a top surface and a bottom surface, the second plate pivotally connected to the first plate and pivotal between a retracted position where the second plate does not substantially contact the ground surface and a stabilizing position where the bottom surface of the second plate is in contact with the ground surface; a member having a proximal end pivotally connected to the first plate and a distal end, the member pivotal between a substantially upright position and a support position where the distal end of the member is in contact with the top of the surface of the second plate when the second plate is in the stabilizing position. In this embodiment, it is preferable that each of the two rear legs of the stepladder have a stabilizing assembly secured thereto.

In yet another aspect, the invention is a second embodiment of a stepladder having high stability. In this embodiment, a first plate is not used to connect the base plate and member to the leg of the stepladder. Instead, the member and a base plate (i.e., the second plate), is pivotally connected directly to a leg of the ladder. In this aspect, the invention is a stepladder comprising a plurality of legs in contact with a ground surface; and a stabilizing assembly secured to an outer surface of at least one of the legs, the stabilizing assembly comprising a base plate having a top surface and a bottom surface, the base plate pivotally connected to the outer surface of the leg and pivotal between a retracted position where the base plate does not substantially contact the ground surface and a stabilizing position where the bottom surface of the base plate is in contact with the ground surface; a member having a proximal end pivotally connected to the outer surface of the leg at a position higher than the base plate and a distal end, the member pivotal between a substantially upright position and a support position where the distal end of the member is in contact with the top of the surface of the base plate when the base plate is in the stabilizing position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of stepladder according to one embodiment of the present invention.

FIG. 2 is a perspective view of a ladder stabilizer according to an embodiment of the present invention.

FIG. 3 is a front view of the ladder stabilizer of FIG. 2.

FIG. 4 is a side view of the ladder stabilizer of FIG. 2 with the base plate in a retracted position and the pole member in a substantially upright position.

FIG. 5 is a side view of the ladder stabilizer of FIG. 2 with the base plate in a stabilizing position and the pole member in the substantially upright position.

FIG. 6 is a side view of the ladder stabilizer of FIG. 2 with the base plate in the stabilizing position and the pole member in the support position.

FIG. 7 is a close-up side view of a bottom portion of a rear leg of the stepladder of FIG. 1, wherein the base plate of the ladder stabilizer is in the retracted position and the pole member of the ladder stabilizer is in the substantially upright position.

FIG. 8 is a close-up side view of a portion of the rear leg of the stepladder of FIG. 1, wherein the base plate of the ladder stabilizer is in the stabilizing position and the pole member of the ladder stabilizer is in the support position.

FIG. 9 is a side view of a bottom portion of a leg of a stepladder according to a second embodiment of the present invention.

FIG. 10 is a schematic of how the size of the base of a stepladder is increased using an embodiment of the ladder stabilizer according to the present invention.

MODES FOR CARRYING OUT THE INVENTION

FIG. 1 illustrates stepladder 10 according to a first embodiment of the present invention. Stepladder 10 has two front legs 11 and two rear legs 12. Steps 13 are provided between front legs 11 for a user to climb. Brace 17 is provided between rear legs 17 for structural integrity. Stepladder 10 further comprises ladder stabilizers 20 secured at the bottom portion 14 of each of the rear legs 12.

Referring now to FIG. 2, ladder stabilizer 20 is illustrated removed from bottom portion 14 of rear leg 12. Ladder stabilizer 20 comprises base plate 21, connection plate 22, and pole member 23. Base plate 24 has top surface 24 and bottom surface 25. Pole member 23 has a distal end 26 and a proximal end 27. Proximal end 27 of pole member 23 is pivotally connected to connection plate 22 so as to be rotatable about axis B-B. Base plate 24 is pivotally connected to connection plate 22 so as to be rotatable about axis A-A. Axis A-A and axis B-B are substantially parallel to one another. Pole member 23 is pivotally connected to connection plate 22 at a higher position on connection plate 22 than is base plate 21.

Turning now to FIGS. 4-6, pole member 23 is pivotally connected to connection plate 23 so as to be capable of rotating about axis B-B between a substantially upright position (as illustrated in FIG. 4) and a support position (as illustrated in FIG. 6). Base plate 21 is pivotally connected to connection plate 22 so as to be capable of rotating about axis A-A between a retracted position (illustrated in FIG. 4) and a stabilization position (which is illustrated in FIG. 5). The fully upright position of pole member 23 and the retracted position of base plate 22 are storage positions in which pole member 23 and base plate 21 are close to rear leg 12 of the stepladder 10 (FIG. 8). When base plate 22 is in the in the stabilization position and pole member 23 is in the support position, stop 38, which is part of distal end 26 of pole member 23, contacts upper surface 24 of base plate 21 (FIG. 6).

Referring now to FIGS. 2 and 3, the pivotal connection of pole member 23 to connection plate 22 is accomplished through the use of mounting brackets 29 which extend outwardly from surface 33 of connection plate 22. Pole member 23 is pivotally connected to mounting brackets 29 with pin 28 (FIG. 3). Mounting brackets 27 are a part of a mounting bracket assembly 34 which is secured to connection plate 22 via bolts 35 which engage nuts 36 (FIG. 4). Alternatively, mounting plates can be formed directly from or welded directly to the connection plate. While a mounting bracket assembly is disclosed as the means for pivotally connecting the member to the connection plate, any means for pivotally connecting two structures can be used to form the pivotal connection.

Proximal end 27 of pole member 23 is not symmetrically shaped. Proximal end 27 is shaped so that an extruding portion of the proximal end 27 contacts flexible plate 37 as pole member 27 is rotated about axis B-B from the support position toward the substantially upright position. When pole member 27 is fully rotated to the substantially upright position, the extruding portion of the proximal end 27 slips free of contact with flexible plate 37. Flexible plate 37 acts as a locking mechanism for keeping pole member 27 in the substantially upright position until the user applies counter rotational force to pole member 23 to rotate pole member 23 about axis B-B back to the support position.

Distal end 26 has a stop 38 connected thereto. Stop 38 is made of rubber and connected to distal end 26 so that it contacts top surface 24 of base plate 21 when pole member 23 is in the support position and base plate 21 is in the stabilizing position. Stop 38 is made of rubber so that pole member 23 does not easily slide with respect to top surface 24 of base plate 21 when it is in contact therewith. Alternatively, this sliding can be restricted by forming a groove into or a ridge extending out of base plate 22 that distal end 26 contacts, preventing horizontal movement.

The pivotal connection of base plate 21 to connection plate 22 is accomplished by extending pin 30 through cylindrical portions 31 of base plate 21 and the cylindrical portion 32 of connection plate 22. This pivotal connection is the same as is used in standard door hinges. Pin 30 is sized so that a tight fit is formed so that base plate 21 can be rotated about axis A-A and hold any position of rotation upon rotational force being removed. Pin 30 is sized so that base plate 21 will not rotate by the affect of gravity or merely moving stepladder 10 during normal use.

Both base plate 21 and connection plate 22 have a plurality of holes 40 spaced throughout. Holes 40 on connection plate 22 are used to secure ladder stabilizer 20 rear leg 12 of stepladder 10 by extending bolts (not illustrated) therethrough and threadily engaging corresponding holes in the rear leg 12. However, connection plate 22 can be connected to rear leg 12 any means known in the art, including for example welding, clamping, or forming a sleeve-type fit.

Referring now to FIG. 7, each ladder stabilizer 20 is connected to a bottom portion 14 of rear leg 12 of stepladder 10. Ladder stabilizer 20 is connect to bottom portion 14 of rear leg 12 so that when base plate 21 is in the stabilizing position, bottom surface 25 of base plate 21 is substantially flush with a bottom surface 16 of leg 12. As such, bottom surface 25 of base plate 21 is in substantial contact with the ground surface 50 upon which leg 12 is resting. When leg 12 is in a flat ground surface, base plate 21 will be substantially horizontal when in the stabilizing position. Base plate 21, when in the stabilizing position and held in place by pole member 23, increases the size of the base of the stepladder to which it is secured.

Referring to FIG. 10, base plate 21 can be sized to so that when it is in the stabilizing position and contacting the ground surface 50, the perimeter P (illustrated in dashed lines)of the base formed by the legs 12 and 11 (FIG. 1) is increased in both width (side to side) and length (back to front). As illustrated, the width is increased from W to W′ and the length is increased from L to L′.

Referring now to FIG. 8, when base plate 21 is moved to retracted position, bottom surface 25 of base plate 21 is not in contact with ground surface 50. The invention is not limited to having ladder stabilizer 20 secured to any set amount of legs of the stepladder, or any specific arrangement. For example, a ladder stabilizer 20 can be secured to all four of the legs or only one.

Referring now to FIG. 9, in another embodiment, the invention can be practiced without the use of a connection plate 22. In this embodiment, ladder stabilizer 60 does not have a connection plate and base plate 21 and pole member 23 are pivotally connected directly to the leg 12 of the stepladder. Pole member 23 is pivotally connected to leg 12 with the mounting bracket assembly 34 discussed above. Base plate 21 is pivotally connected to leg 12 with a similar mounting bracket assembly 62.

Various alternatives, alterations, and modifications should be readily apparent to those skilled in the art without departing from the spirit and scope of the invention. The above embodiments of the acoustical stack can be used for a variety of substrate processing steps, including but not limited to cleaning and stripping.

Claims

1. An apparatus for stabilizing a ladder on a ground surface comprising:

a first plate adapted to be secured to a leg of the ladder;

a second plate having a top surface and a bottom surface, the second plate pivotally connected to the first plate and pivotal between a retracted position where the second plate does not substantially contact the ground surface and a stabilizing position where the bottom surface of the second plate is in contact with the ground surface;

a member having a proximal end pivotally connected to the first plate and a distal end, the member pivotal between a substantially upright position and a support position where the distal end of the member is in contact with the top of the surface of the second plate when the second plate is in the stabilizing position.

2. The apparatus of claim 1 wherein the distal end of the member comprises a rubber stop for contacting the top surface of the second plate when the member is in the support position and the second plate is in the stabilizing position.

3. The apparatus of claim 1 wherein the second plate is sized to increase both width and length of a base perimeter formed by the legs of the ladder when the second plate is in the stabilizing position.

4. The apparatus of claim 1 wherein the first plate comprises mounting brackets extending outward from the first plate for pivotally connecting the proximal end of the member.

5. The apparatus of claim 1 wherein the first plate is rigidly secured to the leg of the ladder by a plurality of bolts.

6. The apparatus of claim 1 wherein the member pivots between the substantially upright position and the support position about a first axis, and the second plate pivots between the retracted position and the stabilizing position about a second axis, the first and second axis being substantially parallel.

7. The apparatus of claim 1 wherein when the second plate is in the stabilizing position, the second plate is substantially horizontal and flush with a bottom surface of the leg of the ladder.

8. The apparatus of claim 1 wherein the member is less than 12 inches in length.

9. A stepladder having high stability comprising:

a plurality of legs in contact with a ground surface; and

a stabilizing assembly having a first plate secured to an outer surface of at least one of the legs, a second plate having a top surface and a bottom surface, the second plate pivotally connected to the first plate and pivotal between a retracted position where the second plate does not substantially contact the ground surface and a stabilizing position where the bottom surface of the second plate is in contact with the ground surface; a member having a proximal end pivotally connected to the first plate and a distal end, the member pivotal between a substantially upright position and a support position where the distal end of the member is in contact with the top of the surface of the second plate when the second plate is in the stabilizing position.

10. The stepladder of claim 9 wherein the distal end of the member comprises a rubber stop for contacting the top surface of the second plate when the member is in the support position and the second plate is in the stabilizing position.

11. The stepladder of claim 9 wherein the number of legs is four, the four legs forming a base perimeter having a length and width, the second plate sized to increase both the width and length of the base perimeter when in the stabilizing position.

12. The stepladder of claim 9 wherein the first plate comprises mounting brackets extending outward from the first plate for pivotally connecting the proximal end of the member.

13. The stepladder of claim 9 wherein the first plate is rigidly secured to the outer surface of the leg of the ladder by a plurality of bolts.

14. The stepladder of claim 9 wherein the member pivots between the substantially upright position and the support position about a first axis, and the second plate pivots between the retracted position and the stabilizing position about a second axis, the first and second axis being substantially parallel.

15. The stepladder of claim 9 wherein when the second plate is in the stabilizing position, the second plate is substantially horizontal and flush with a bottom surface of the leg of the ladder to which the first plate is secured.

16. The stepladder of claim 9 comprising two front legs and two rear legs, each of the two rear legs having the stabilizing assembly secured thereto.

17. The stepladder of claim 9 wherein the member is less than 12 inches in length.

18. A stepladder having high stability comprising:

a plurality of legs in contact with a ground surface; and

a stabilizing assembly secured to an outer surface of at least one of the legs, the stabilizing assembly comprising a base plate having a top surface and a bottom surface, the base plate pivotally connected to the outer surface of the leg and pivotal between a retracted position where the base plate does not substantially contact the ground surface and a stabilizing position where the bottom surface of the base plate is in contact with the ground surface; a member having a proximal end pivotally connected to the outer surface of the leg at a position higher than the base plate and a distal end, the member pivotal between a substantially upright position and a support position where the distal end of the member is in contact with the top of the surface of the base plate when the base plate is in the stabilizing position.

19. The stepladder of claim 18 wherein the distal end of the member comprises a rubber stop for contacting the top surface of the base plate when the member is in the support position and the base plate is in the stabilizing position.

20. The stepladder of claim 18 wherein the number of legs is four, the four legs forming a base perimeter having a length and width, the base plate sized to increase both the width and length of the base perimeter when in the stabilizing position.

21. The stepladder of claim 18 wherein the member pivots between the substantially upright position and the support position about a first axis, and the base plate pivots between the retracted position and the stabilizing position about a second axis, the first and second axis being substantially parallel.

22. The stepladder of claim 18 wherein when the base plate is in the stabilizing position, the second plate is substantially horizontal and is substantially flush with a bottom surface of the leg of the ladder.

23. The stepladder of claim 18 comprising two front legs and two rear legs, each of the two rear legs having the stabilizing assembly secured thereto.

24. The step ladder of claim 18 wherein the member is less than 12 inches in length.