阅读说明：本技术 伸展梯、用于定位其的方法和用于移动其的系统 (Extension ladder, method for positioning same and system for moving same ) 是由 D·C·莫拉 K·金 于 2019-07-30 设计创作，主要内容包括：本申请涉及一种伸展梯、用于定位其的方法和用于移动其的系统。所述伸展梯包括：底座区段,其具有右底座轨和与所述右底座轨成平行且间隔关系的左底座轨；飞行区段,其具有右飞行轨和与所述右飞行轨成平行且间隔关系的左飞行轨；顶盖,其附接到所述右飞行轨的顶部；和锁定机构,其在相对于所述底座区段的所需位置处将所述飞行区段固定和锁定到所述底座区段。(The present application relates to an extension ladder, a method for positioning the same and a system for moving the same. The extension ladder comprises: a base section having a right base rail and a left base rail in parallel and spaced relation to the right base rail; a flight section having a right flight rail and a left flight rail in parallel and spaced relation to the right flight rail; a top cap attached to a top of the right flight rail; and a locking mechanism to secure and lock the flight segment to the base segment at a desired position relative to the base segment.)

1. An extension ladder, comprising:

a base section having a right base rail and a left base rail in parallel and spaced relation to the right base rail, the right base rail having a C-shaped cross section formed from a right base flange attached to a base web and a left base flange attached to the base web, wherein the base web is disposed between the right base flange and the left base flange, the base section having a base ledge attached to the right base rail and the left base rail and disposed forward and outward of the right base flange of the right base rail;

a flight section having a right flight rail and a left flight rail in parallel and spaced relation to the right flight rail, the flight section having a flight rung attached to and extending therebetween, the right and left base flanges disposed about the right flight rail, wherein the right flight rail is disposed between the right and left base flanges, the flight section nested in the base section and configured to slide at least a portion of the flight section upward over and downward back relative to the base section when held in engagement with the base section via the right and left base rails disposed about the right and left flight rails, respectively, the right flight rail being formed from a right flight flange attached to a flight web and a left flight flange shape attached to the flight web Wherein the flight web is disposed between the right flight flange and the left flight flange, the right flight rail having a top and a bottom, the top being part of the portion configured to slide upward over the base section;

a top cap attached to the top, the top cap having a surface extending between the right flight flange and the flight web and the left flight flange; and

a locking mechanism to secure and lock the flight segment to the base segment at a desired position relative to the base segment.

2. The extension ladder of claim 1, wherein the right base rail has a right guide rod extending inwardly from the right base flange toward the left base flange and has a left guide rod extending inwardly from the left base flange toward the right base flange, the right and left guide rods positioning the right flight rail a desired distance between the right base flange and the left base flange and acting as a guide for the right flight rail when the right flight rail moves relative to the right base rail and into a position where the right flight rail flips away from a rivet.

3. The extension ladder of claim 2, wherein a first one of the base rungs has a first flat end, the first flat end coinciding with and resting on and in contact with and parallel to the right base flange of the right base rail, at least a first fastener extending through the first flat end and the right base flange to secure the first flat end to the right base flange, the first base rail having a second flat end secured to the left base rail with a second fastener, the first base rail having a stepped portion that is flat and extends between the first flat end and the second flat end, the flat stepped portion is oriented substantially perpendicular to the first and second flat ends.

4. The extension ladder of claim 3, wherein the first base rung has a first tapered portion having an inwardly extending slope between the stepped portion and the first flat end, and a second tapered portion having an inwardly extending slope between the stepped portion and the second flat end.

5. The extension ladder of claim 4, wherein the top cap has an attachment portion disposed between and extending along the flight web and the right and left flight flanges, and a ceiling portion attached to and extending from the attachment portion and above the attachment portion, the ceiling portion having a solid surface and a peripheral edge defining a ridge extending along the top of the right flight rail in contact and on the top of the right flight rail and on the flight web and the right and left flight flanges.

6. The extension ladder of claim 5, wherein the ceiling portion extends upwardly in an arc.

7. The extension ladder of claim 6, wherein the ceiling portion has ribs disposed on the solid surface.

8. The extension ladder of claim 7, wherein the locking mechanism is a J-lock extending from one side of a rung of the base section and rearwardly through a lock hole in the right base rail and into a rung of the flight section to lock the flight section and the base section together, the flight section configured to slide relative to the base section when the J-lock is pulled out of the rung of the flight section; or a swing lock attached to the right and left flight flanges of the right base rail and surrounding a rung of the base section and an adjacent rung of the flight section at a desired position of the flight section relative to the base section.

9. The extension ladder of claim 8, wherein the right flight rail has walls attached to and extending between the right and left flight flanges and in parallel and spaced relation to the flight web, the flight web and walls and the right and left flight flanges forming a rectangular cross-sectional shape.

10. The extension ladder of claim 9, comprising a second extension ladder having a flight section nested in a foot section, the second extension ladder stacked on the extension ladder and having a stack height at least 1/3 less than a stack height of a first extension ladder, a first extension ladder having a flight section on top of a foot section stacked on a second extension ladder having a flight section on top of a foot section.

11. A method of positioning an extension ladder, comprising the steps of:

moving the extension ladder to a desired position;

sliding a flight section of the extension ladder to a desired length relative to a base section of the extension ladder; and

leaning the extension ladder against an object, the base section having a right base rail and a left base rail in parallel and spaced relation to the right base rail, the right base rail having a C-shaped cross section formed of a right base flange attached to a base web and a left base flange attached to the base web, wherein the base web is disposed between the right base flange and the left base flange, the base section having a base ledge attached to the right base rail and the left base rail and disposed forward and outward of the right base flange of the right base rail; the flight section having a right flight rail and a left flight rail in parallel and spaced relation to the right flight rail, the flight section having a flight rung (32) attached to and extending between the right flight rail and the left flight rail, the right base flange and the left base flange disposed about the right flight rail with the right flight rail disposed between the right base flange and the left base flange, the flight section nested in the base section and configured to slide at least a portion of the flight section upward over the base section and slide the flight section back downward relative to the base section while remaining engaged with the base section via the right base rail and the left base rail disposed about the right flight rail and the left flight rail, respectively, the right flight rail is formed from a right flight flange attached to a flight web and a left flight flange attached to the flight web, wherein the flight web is disposed between the right flight flange and the left flight flange, the right flight rail having a top and a bottom, the top being part of the portion configured to slide upward over the base section; the spreader ladder having a top cap attached to the top, the top cap having a surface extending between the right flight flange and the flight web and the left flight flange; and the extension ladder has a locking mechanism that secures and locks the flight section to the base section at a desired position relative to the base section.

12. The method of claim 11, wherein the right base rail has a right guide rod extending inwardly from the right base flange toward the left base flange and has a left guide rod extending inwardly from the left base flange toward the right base flange, the right and left guide rods positioning the right flight rail a desired distance between the right base flange and the left base flange and acting as a guide for the right flight rail when the right flight rail moves relative to the right base rail and to a position where the right flight rail flips away from a rivet.

13. The method of claim 12, wherein a first one of the base rails has a first flattened end, the first flat end coinciding with and resting on and in contact with and parallel to the right base flange of the right base rail, at least a first fastener extending through the first flat end and the right base flange to secure the first flat end to the right base flange, the first base rail having a second flat end secured to the left base rail with a second fastener, the first base rail having a stepped portion that is flat and extends between the first flat end and the second flat end, the flat stepped portion is oriented substantially perpendicular to the first and second flat ends.

14. The method of claim 13, wherein the first base rail has a first tapered portion with an inwardly extending slope between the stepped portion and the first flat end, and a second tapered portion with an inwardly extending slope between the stepped portion and the second flat end.

15. The method of claim 14, wherein the cap has an attachment portion disposed between and extending along the flight web and the right and left flight flanges, and a ceiling portion attached to and extending from the attachment portion and above the attachment portion, the ceiling portion having a solid surface and a peripheral edge defining a ridge extending along the top of the right flight rail in contact and on the top of the right flight rail and on the flight web and the right and left flight flanges.

16. The method of claim 15, wherein the ceiling portion extends upwardly in an arc.

17. The method of claim 16, wherein the suspended ceiling portion has ribs disposed on the solid surface.

18. The method of claim 17, wherein the locking mechanism is a J-lock that extends from one side of a rung of the base section and back through a locking hole in the right base rail and into a rung of the flight section to lock the flight section and the base section together, the flight section configured to slide relative to the base section when the J-lock is pulled out of the rung of the flight section; or a swing lock attached to the right and left flight flanges of the right base rail and surrounding a rung of the base section and an adjacent rung of the flight section at a desired position of the flight section relative to the base section.

19. The method of claim 18, wherein the right flight rail has walls attached to and extending between the right and left flight flanges and in parallel and spaced relation to the flight web, the flight web and walls and the right and left flight flanges forming a rectangular cross-sectional shape.

20. A system for moving an extension ladder, the extension ladder comprising a first extension ladder having a flight section nested in a foot section and a second extension ladder having a flight section nested in a foot section, the second extension ladder stacked on the extension ladder and having a stack height at least 1/3 less than a stack height of the first extension ladder, the first extension ladder having a top flight section on a foot section stacked on the second extension ladder having a top flight section on a foot section.

Technical Field

The invention relates to an extension ladder with a flight section, the rails of which are nested in the rails of a rail section. (As used herein, references to "the invention" or "the invention" relate to exemplary embodiments and not necessarily to each and every embodiment encompassed by the appended claims). (As used herein, references to "the invention" or "the invention" relate to exemplary embodiments and not necessarily to each and every embodiment encompassed by the appended claims). More particularly, the present invention relates to an extension ladder having a flight section rail nested in a foot section rail, wherein the foot section rail has a guide rod to position and guide the flight section rail as it moves relative to the foot section rail.

Background

This section is intended to introduce the reader to various aspects of art, which may be associated with various aspects of the present invention. The following discussion is intended to provide information to facilitate a better understanding of the present invention. Accordingly, it should be understood that statements in the following discussion are to be read in this light, and not as admissions of prior art.

The extension ladder provides the convenience of having a base section and a flight section attached to the exterior of the base section that moves relative to the base section to extend the extension ladder an effective length to reach variable height. The flight section is stacked on the base section, which essentially requires a certain volume, i.e. the length and the width of the flight section aligned with and on the base section, the width being the width of the rails of the base section and the width of the rails of the flight section. There may be situations for storage purposes where it is difficult to place the extension ladder out of the way because of its width. Furthermore, when transporting a number of extension ladders, the number of extension ladders placed beside and on each other is limited by the total width available to accommodate the ladders together, such as in the cargo area of a truck.

Disclosure of Invention

The invention relates to an extension ladder. The ladder includes a base section having a right base rail and a left base rail in parallel and spaced relation to the right base rail. The right base rail has a C-shaped cross section formed by a right base flange attached to the base web and a left base flange attached to the base web, wherein the base web is disposed between the right base flange and the left base flange. The base section has a base rail attached to the right and left base rails and disposed forward and outward of the right base flange of the right base rail.

The ladder includes a flight section having a right flight rail and a left flight rail in parallel and spaced relation to the right flight rail. The flight section has flight rungs attached to and extending between the right and left flight rails. The right and left base flanges are disposed about the right flight rail, wherein the right flight rail is disposed between the right and left base flanges. The flight section nests in the foot section and is configured to slide at least a portion of the flight section upward over the foot section and slide the flight section back downward relative to the foot section when held in engagement with the foot section via right and left foot rails disposed about the right and left flight rails, respectively. The right flight rail is formed from a right flight flange attached to a flight web and a left flight flange attached to a flight web, wherein the flight web is disposed between the right flight flange and the left flight flange. The right flight rail has a top and a bottom. The top is the portion of the portion configured to slide upward over the base section. The ladder includes a top cap attached to the top. The top cap has a surface extending between the right flight flange and the flight web and the left flight flange. The ladder includes a locking mechanism that secures and locks the flight section to the base section at a desired position relative to the base section.

The invention relates to a method for positioning an extension ladder. The method includes the step of moving the extension ladder to a desired position. There is the step of sliding the flight section of the extension ladder to a desired length relative to the base section of the extension ladder. There is the step of reclining the extension ladder against the object. The base section has a right base rail and a left base rail in parallel and spaced relation to the right base rail. The right base rail has a C-shaped cross section formed by a right base flange attached to the base web and a left base flange attached to the base web, wherein the base web is disposed between the right base flange and the left base flange. The base section has a base rail attached to the right and left base rails and disposed forward and outward of the right base flange of the right base rail. The flight section has a right flight rail and a left flight rail in parallel and spaced relation to the right flight rail. The flight section has flight rungs attached to and extending between the right and left flight rails. The right and left base flanges are disposed about the right flight rail, wherein the right flight rail is disposed between the right and left base flanges. The flight section nests in the foot section and is configured to slide at least a portion of the flight section upward over the foot section and slide the flight section back downward relative to the foot section when held in engagement with the foot section via right and left foot rails disposed about the right and left flight rails, respectively. The right flight rail is formed from a right flight flange attached to a flight web and a left flight flange attached to a flight web, wherein the flight web is disposed between the right flight flange and the left flight flange. The right flight rail has a top and a bottom. The top is the portion of the portion configured to slide upward over the base section. The ladder includes a top cap attached to the top. The top cap has a surface extending between the right flight flange and the flight web and the left flight flange. The ladder includes a locking mechanism that secures and locks the flight section to the base section at a desired position relative to the base section.

Drawings

The preferred embodiments of the present invention and the preferred methods of practicing the present invention are illustrated in the accompanying drawings, in which:

FIG. 1 is a perspective view of the extension ladder of the present invention with the flight section retracted and nested in and alongside the foot section.

Fig. 2 is a perspective view of the extension ladder with the flight section nested in and extending above the foot section.

Fig. 3 shows a cross-sectional view of a J-lock.

Fig. 4A and 4B show details of how the rungs are attached to the flight section and the base section, respectively.

Fig. 5 shows a perspective view of the upper end of the extension ladder with the flight rail having a rectangular cross section nested in the base rail with a J-lock.

Fig. 6 shows a top view of an extension ladder, wherein the flight rail has a rectangular cross section with a J-lock nested in the base rail.

Fig. 7 shows a perspective view of the upper end of the extension ladder with the flight rail having a rectangular cross section nested in the base rail with a swing lock.

Fig. 8 shows a top view of an extension ladder, wherein the flight rail has a rectangular cross section nested in the base rail with a swing lock.

Fig. 9 shows a perspective view of the upper end of the extension ladder with the flight rail having a C-shaped cross section nested in the base rail with a J-lock.

Fig. 10 shows a top view of an extension ladder with a flight rail having a C-shaped cross section nested in a base rail with a J-lock.

Fig. 11 shows a perspective view of the upper end of the extension ladder with the flight rail having a C-shaped cross-section nested in the base rail with a swing lock.

Fig. 12 shows a top view of an extension ladder, wherein the flight rail has a C-shaped cross-section nested in the base rail with a swing lock.

Fig. 13 shows a C-shaped cross section of the base rail above a rectangular or square frame shaped cross section of the flight rail using a J-lock.

Fig. 14 shows a C-shaped cross section of the base rail above a rectangular or square frame shaped cross section of the flight rail using a pendulum lock.

Fig. 15 shows a C-shaped cross section of the base rail above a C-shaped cross section of the flight rail using a J-lock.

Fig. 16 shows a C-shaped cross section of the base rail above the C-shaped cross section of the flight rail using a pendulum lock.

Fig. 17A is a top perspective view of the top cover.

Fig. 17B is a lower perspective view of the top cover.

Fig. 18 is a top view of the extension ladder at maximum extension.

Fig. 19 is a side view of the extension ladder at maximum extension.

Fig. 20 shows a typical base rail profile.

Fig. 21 shows a typical C-shaped flight rail profile.

FIG. 22 illustrates a typical rectangular flight rail profile.

Fig. 23 is a side view of three extension ladders stacked on top of each other.

Fig. 24 is a top view of three extension ladders stacked on top of each other.

Detailed Description

Referring now to the drawings, wherein like reference numerals refer to similar or identical parts throughout the several views, and more particularly to fig. 1 and 2 herein, an extension ladder 10 is shown. The ladder 10 includes a base section 12 having a right base rail 14 and a left base rail 16 in parallel and spaced relation to the right base rail 14. The right base rail 14 has a C-shaped cross section formed by a right base flange 18 attached to a base web 20 and a left base flange 22 attached to the base web 20, with the base web 20 disposed between the right base flange 18 and the left base flange 22, as shown in fig. 20. The base section 12 has a base rail 24 that is attached to the right and left base rails 14, 16 and is disposed forward and outward of the right base flange 18 of the right base rail 14.

The ladder 10 includes a flight section 26 having a right flight rail 28 and a left flight rail 30 in parallel and spaced relation to the right flight rail 28. The flight section 26 has flight rungs 32 attached to and extending between the right and left flight rails 28, 30. Right base flange 18 and left base flange 22 are disposed about right flight rail 28, with right flight rail 28 disposed between right base flange 18 and left base flange 22. The flight section 26 is nested in the foot section 12, and is configured to slide at least a portion of the flight section 26 upwardly over the foot section 12 and slide the flight section 26 back downwardly relative to the foot section 12 when held in engagement with the foot section 12 via the right and left foot rails 14, 16 disposed about the right and left flight rails 28, 30, respectively. The right flight rail 28 is formed from a right flight flange 34 attached to a flight web 36 and a left flight flange 38 attached to the flight web 36, with the flight web 36 disposed between the right flight flange 34 and the left flight flange 38, as shown in fig. 21 and 22. Right flight rail 28 has a top 40 and a bottom 42. The top 40 is the part of the portion that is configured to slide upward over the base section 12. The base rail and the flight rail may be made of aluminum or fiberglass. Preferably, the base rail and the flight rail are straight.

The flight sections 26 can be nested in at least two ways. In one approach, the flight web 36 is adjacent and alongside the base web 20 as the right and left flight flanges 34, 38 extend outwardly from the flight web 36 away from the centerline 50 of the extension ladder 10, as shown in fig. 11 and 12. In another approach, the flight web 36 is spaced from the base web 20 as the right and left flight flanges 34, 38 extend inwardly from the flight web 36 toward the centerline 50 of the extension ladder 10, as shown in fig. 9 and 10.

The ladder 10 includes a roof 44 as shown in fig. 17A and 17B attached to the roof 40, wherein no object is attached to the roof 44 above the roof 44. The top cover 44 has a surface 46 extending between the right flight flange 34 and the flight web 36 and the left flight flange 38. The ladder 10 includes a locking mechanism 48 that secures and locks the flying section 26 to the base section 12 at a desired position relative to the base section 12. The extension ladder 10 can support at least 300 pounds and has a load rating of at least 1A.

Right base rail 14 may have a right guide bar 52 extending from right base flange 18 inward toward left base flange 22, and a left guide bar 54 extending from left base flange 22 inward toward right base flange 18, as shown in fig. 6, 8, 10, 12, and 20. Right guide bar 52 and left guide bar 54 position right flight rail 28 a desired distance between the right and left base flanges, and serve as a guide for right flight rail 28 as right flight rail 28 moves relative to right base rail 14 and to a position where right flight rail 34 is flipped away from the rivets. The guide rods additionally serve to stiffen right base rail 14 and add support and stiffness to right base rail 14. The guide bar extends along the length of right base rail 14. Additional guide rods 56 may be present, such as one additional guide rod 56, in spaced relation and parallel to right guide rod 52 and also left guide rod 54 to further act as a guide for right flight rail 28 as right flight rail 28 moves relative to right base rail 14. The guide rods are used to tighten the tolerance between right flight rail 28 and right base rail 14. Left base rail 16 may have guide rods in common with right base rail for the same purpose and function as right base rail 14. The guide bar may be between.1 and.2 inches in length and may be about.1 inches in width.

First base rail 58 of base rail 24 may have a first flat end 60 that is coincident with and rests on and is in contact with and parallel to right base flange 18 of right base rail 14, as shown in fig. 5, 7, 9, and 11. The base section 12 may have at least a first fastener 62, such as a rivet, extending through the first flat end 60 and the right base flange 18 to fasten the first flat end 60 to the right base flange 18. The first base rail 58 can have a second flat end 64 that is fastened to the left base rail 16 with a second fastener 66. First base rail 58 may have a stepped portion 68 that is flat and extends between first flat end 60 and second flat end 64. The flat stepped portion 68 may be oriented substantially perpendicular to the first and second flat ends 60, 64. The first base rail 58 may have a first tapered portion 70 with an inwardly extending sloped portion 72 between the stepped portion 68 and the first flat end 60, and a second tapered portion 74 with an inwardly extending sloped portion 72 between the stepped portion 68 and the second flat end 64. The flat end and its tapered portion are formed by crimping, with the tapered portion having an incline 72 of between 20 and 65 degrees, and preferably about 45 degrees. In this manner, the inclined portion 72 is not so severe as to form a crack or break in the crimp or taper portion during the crimping process. The tapered portion is about 1.5 inches to about 3 inches from the inner edge of the right base flange 18, as is the left side of the rail.

The flight rail 32 may be forged to the flight webs 36 of the first and second flight rails and form a forged joint 69, as shown in fig. 4A. The rungs may be hollow and have stepped portions 68 with grooves or serrations to provide traction when a user places a foot on the tread surface 46 of the flight rung.

The top cap 44 may have attachment portions 76 disposed between and extending along the flight web 36 and the right and left flight flanges 34, 38, and a ceiling portion 78 attached to and extending from the attachment portions 76 and above the attachment portions, as shown in fig. 17A and 17B. The suspended ceiling portion 78 has a solid surface 46 and a peripheral edge that defines a ridge extending along the top 40 of the right flight rail 28 in contact and on top of the right flight rail and on the web 36 and the right and left flight flanges 34, 38. The ceiling portion 78 may extend upwardly in an arc. The suspended ceiling portion 78 may have ribs 80 disposed on the solid surface 46. There are no additional sections of the ladder 10 extending from the flight section 26 or from above the canopy 44, and there are no hinges extending above the flight section 26 attached to the flight section 26 of the ladder 10. The bottom 42 of each base rail (on which the extension ladder 10 rests on the ground) is the bare rail itself or has a foot 82 on the bottom 42 when the extension ladder 10 is reclined on an object.

Locking mechanism 48 may be a J-lock 84 that extends from one side of J-lock ledge 25 of base section 12 and back through locking hole 71 in right base rail 14 and through the end of ledge 32 (which is hollow) into the ledge of flight section 26 to lock flight section 26 and base section 12 together, as shown in fig. 3. Flight section 26 and base section 12 are configured in the locked position so that their rungs are side-by-side with each other so that the overlapping portions of flight section 26 and base section 12 have their steps in line so that a user's foot rests on and steps on the rungs of base section 12 and the aligned adjacent rungs of flight section 26. The flight section 26 is configured to slide relative to the base section 12 when the J-lock 84 is pulled out of the crosspiece of the flight section 26. The J-lock rail 25 from which the J-lock 84 extends may have a squared or flat surface 86 rather than a crimped end. The J-lock 84 sits in and extends from a flat surface 86, as shown in fig. 3, 13 and 15. Alternatively, locking mechanism 48 may be a swing lock 88 that is attached to right and left flight flanges 34, 38 of right base rail 14 and that encompasses a rung of base section 12 and an adjacent rung of flight section 26 at a desired position of flight section 26 relative to base section 12, as shown in fig. 14 and 16.

The right flight rail 28 may have walls 90 attached to and extending between the right and left flight flanges 34, 38 and in parallel and spaced relation to the flight web 36, as shown in fig. 5-8. The flight web 36 and wall 90 and the right and left flight flanges 34 and 38 form a rectangular cross-sectional shape with the wall 90 closing a C-cross section. This is another way in which flight section 26 can be nested within base section 12, with right flight rail 28 nested in right base rail 14. Fig. 5 and 6 illustrate this embodiment using a J-lock 84, wherein the flight bar 32 has a hollow rectangular cross-section corresponding to the cross-section of the J-lock seated in the flight bar. Fig. 7 and 8 illustrate this embodiment using a pendulum lock 88, wherein the flight bar 32 has a D-shaped cross-section, wherein the stepped portion 68 of the flight bar has a slight downward angle to better receive the user's foot when the user places the foot on the flight bar.

Fig. 13 shows a C-shaped cross section of the base rail above the rectangular or square frame shaped cross section of the flight rail using a J-lock 84. Fig. 14 shows a C-shaped cross section of the base rail above the rectangular or square frame shaped cross section of the flight rail using a pendulum lock 88. Fig. 15 shows a C-shaped cross section of the base rail above the C-shaped cross section of the flight rail using a J-lock 84. Fig. 16 shows a C-shaped cross section of the base rail above the C-shaped cross section of the flight rail using a pendulum lock 88.

Fig. 18 is a top view of the extension ladder 10 at maximum extension. Fig. 19 is a side view of the extension ladder 10 at maximum extension.

Fig. 20 shows a typical base rail profile. Fig. 21 shows a typical C-shaped flight rail profile. FIG. 22 illustrates a typical rectangular flight rail profile.

The present invention is directed to a method of positioning an extension ladder 10. The method includes the step of moving the extension ladder 10 to a desired position. There is the step of sliding the flight section 26 of the extension ladder 10 to a desired length relative to the base section 12 of the extension ladder 10. There is the step of reclining the extension ladder 10 against the object. The base section 12 has a right base rail 14 and a left base rail 16 in parallel and spaced relation to the right base rail 14. The right base rail 14 has a C-shaped cross section formed by a right base flange 18 attached to a base web 20 and a left base flange 22 attached to the base web 20, with the base web 20 disposed between the right base flange 18 and the left base flange 22. The base section 12 has a base rail 24 that is attached to the right and left base rails 14, 16 and is disposed forward and outward of the right base flange 18 of the right base rail 14. Flight section 26 has a right flight rail 28 and a left flight rail 30 in parallel and spaced relation to right flight rail 28. The flight section 26 has flight rungs 32 attached to and extending between the right and left flight rails 28, 30. Right base flange 18 and left base flange 22 are disposed about right flight rail 28, with right flight rail 28 disposed between right base flange 18 and left base flange 22. The flight section 26 is nested in the foot section 12, and is configured to slide at least a portion of the flight section 26 upwardly over the foot section 12 and slide the flight section 26 back downwardly relative to the foot section 12 when held in engagement with the foot section 12 via the right and left foot rails 14, 16 disposed about the right and left flight rails 28, 30, respectively. The right flight rail 28 is formed from a right flight flange 34 attached to a flight web 36 and a left flight flange 38 attached to the flight web 36, with the flight web 36 disposed between the right flight flange 34 and the left flight flange 38. Right flight rail 28 has a top 40 and a bottom 42. The top 40 is the part of the portion that is configured to slide upward over the base section 12. The ladder 10 includes a roof 44 attached to the roof 40, with no objects attached above the roof 44. The top cover 44 has a surface 46 extending between the right flight flange 34 and the flight web 36 and the left flight flange 38. The ladder 10 includes a locking mechanism 48 that secures and locks the flying section 26 to the base section 12 at a desired position relative to the base section 12.

By extending the ladder 10 with the fly section 26 rails nested inside the C-channel rails of the foot section 12, the front to rear dimension of the ladder 10 is reduced. The flight section 26 has a standard rung design that provides a wide comfortable standing surface 46 when climbing high. Base section 12 has a ledge with a flat end that is riveted to the outside of the front flange of the rail. This configuration allows the flight section to move freely within the base section 12 as the flight section is extended or retracted. The flight section and base section 12 can be held in place relative to each other by using a J-lock 84, using a conventional extension ladder rung lock, or other latching mechanism.

Conventional extension ladders have rail sections stacked on top of each other. The height of the extension ladders stacked on top of each other is defined as the stacking height. As shown in fig. 23 and 24, the smaller stack height 92 of the extension ladder 10 stacked on top of each other allows for higher product density on palletizing and containerizing, which will reduce shipping costs. For example, when in transit, a first extension ladder having a second extension ladder placed on top of or alongside the first extension ladder has a stack height 92 that is less 1/3 than the stack height of a first conventional extension ladder having a second conventional extension ladder placed on top of or alongside the first conventional extension ladder, wherein the conventional extension ladder has a flight section 26 alongside the base section 12 but not nested in the base section 12. For example, where two conventional extension ladders are stacked on top of each other, the stack height will be at least the height of the width of four rails (i.e., the width of the base and flight rails of a first conventional extension ladder plus the width of the base and flight rails of a second conventional ladder on top of the first conventional ladder). In the case of two extension ladders 10, the stack height is about the width of the base rail 14 of the first extension ladder 10 plus the width of the base rail 14 of the second extension ladder 10 on top of the first extension ladder 10.

Although the invention has been described in detail in the foregoing embodiments for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention except as it may be described by the following claims.