Rigidified step ladder

• US 20040231920A1
• Filed: 05/22/2003
• Published: 11/25/2004
• Est. Priority Date: 05/22/2003
• Status: Active Grant

• Current Assignee: Dorel Home Furnishings, Inc. (Dorel Industries Incorporated)
• Original Assignee: Cosco Management Incorporated (Dorel Industries Incorporated)
• Inventors: Meeker, Paul K.
• Granted Patent: US 7,108,103 B2
• Time in Patent Office: Days
• US Class Current: 182/165
• CPC Class Codes: E06C 1/393 Ladders having platforms foldable with the ladder
• CPC Class Codes: E06C 7/087 with a connecting piece installed around the rung

Abstract

A step ladder includes rigidified left and right legs and step units between the legs. Each rigidified leg includes a web interconnecting first and second tubular members. Each step unit includes a hollow step including an internal rigidifying partition wall and step mounts for coupling the hollow step to the legs.

Claims

1. A step ladder comprising

a frame including a left leg and a right leg, each of the left and right legs including spaced-apart first and second tubular members and a web located between and coupled to the first and second tubular members, and

a plurality of step units arranged to lie between the left and right legs, each step unit being coupled to the left and right legs to support said step unit in a fixed position relative to the left and right legs.

2. The step ladder of claim 1, wherein each of the first and second tubular members of the left leg includes first, second, third, and fourth side walls arranged in series to define an interior region therebetween.

3. The step ladder of claim 2, wherein the first side walls of said first and second tubular members lie in coextensive relation with a first reference plane, the second side walls of the said first and second tubular members are coupled to the web located between the first and second tubular members, and the third side walls of said first and second tubular members lie in coextensive relation with a second reference plane that is oriented to cooperate with the first reference plane to define a first acute included angle therebetween.

4. The step ladder of claim 3, wherein the web is arranged to lie closer to the first reference plane than to the second reference plane to lie in offset relation to a central reference plane bisecting the second side walls of said first and second tubular members.

5. The step ladder of claim 3, wherein portions of the second side walls of said first and second tubular members are located in spaced-apart parallel relation to one another.

6. The step ladder of claim 3, wherein the second side wall of each of said first and second tubular members includes a short wall portion arranged to interconnect the web and the first side wall of said first tubular member and a relatively longer long wall portion arranged to interconnect the web and the third side wall, the short wall portions of said first and second tubular members are arranged to lie in confronting relation to one another and are separated by a first distance, the long wall portions of said first and second tubular members are arranged to lie in confronting relation to one another and are separated by a second distance that is greater than the first distance.

7. The step ladder of claim 6, wherein the short wall portions of said first and second tubular members are arranged to lie in spaced-apart parallel relation to one another and the long wall portions of said first and second tubular members are arranged to lie in spaced-apart parallel relation to one another.

8. The step ladder of claim 3, wherein each of the first and second tubular members of the right leg includes first, second, third, and fourth side walls arranged in series to define an interior region therebetween, the first side walls of the first and second tubular members of the right leg lie in coextensive relation with a third reference plane that lies in spaced-apart parallel to the first reference plane, the second side walls of the first and second tubular members of the right leg are coupled to the web located between the first and second tubular members of the right leg, and the third side walls of the first and second tubular members of the right leg lie in coextensive relation with a fourth reference plane that is oriented to cooperate with the third reference plane to define a second acute included angle therebetween.

9. The step ladder of claim 8, wherein the first acute included angle is substantially equivalent to the second acute included angle.

10. The step ladder of claim 8, wherein the fourth reference plane is oriented to cooperate with the first reference plane to define a third acute included angle therebetween.

11. The step ladder of claim 2, wherein the interior region of the first tubular member has a volume that is less than a volume of the interior region of the second tubular member.

12. The step ladder of claim 2, wherein each of the first and second tubular members of the right leg include first, second, third, and fourth side walls arranged in series to define an interior region therebetween.

13. The step ladder of claim 12, wherein the interior region of the first tubular member of the left leg has a volume that is substantially equivalent to a volume of the interior region of the first tubular member of the right leg, the interior region of the second tubular member of the left leg has a volume that is substantially equivalent to a volume of the interior region of the second tubular member of the right leg, and the volume of each of the first tubular members is less than the volume of each of the second tubular members.

14. The step ladder of claim 1, wherein a first of the step units includes a step, a pair of step mounts, each step mount being configured to mate with one end of the step and the first and second tubular members of one of the legs, and at least one fastener for each of the step mounts, and wherein each fastener is arranged to anchor a companion step mount to one of the legs to support the step mated with the step mounts in a horizontally extending fixed position between the left and right legs.

15. The step ladder of claim 14, wherein each step mount includes a first plate arranged to abut a companion first tubular member, a second plate arranged to abut a companion second tubular member, and a mount anchor positioned to lie between the first and second plates and extend into an anchor-receiving channel defined by the companion first and second tubular members and the web located between the companion first and second tubular members.

16. The step ladder of claim 15, wherein each step mount further includes a mount flange positioned to lie in spaced-apart relation to the mount anchor to locate at least a portion of the first plate therebetween and to define a first tube channel receiving a portion of the first tubular member associated with said step mount therein.

17. The step ladder of claim 15, wherein the mount anchor and the second plate of each step mount are oriented relative to one another to define a second tube channel receiving a portion of the second tubular member associated with said step mount therein.

18. The step ladder of claim 15, wherein each step mount further includes a mount flange positioned to lie in spaced-apart relation to the mount anchor to locate at least a portion of the first plate therebetween and to define a first tube channel receiving a portion of the first tubular member associated with said step mount therein and the mount anchor and the second plate of each step mount are oriented relative to one another to define a second tube channel receiving a portion of the second tubular member associated with said step mount therein.

19. The step ladder of claim 15, wherein the anchor mount is arranged to abut the web.

20. The step ladder of claim 15, wherein each of the web and the anchor mount is formed to include a fastener-receiving aperture, the fastener-receiving apertures are in alignment with one another, and the fastener extends through the fastener-receiving apertures.

21. The step ladder of claim 20, wherein the step is formed to include means for mating with a distal portion of the fastener extending through said fastener-receiving apertures so that said step and step mount are anchored in a fixed position relative to said first and second tubular members.

22. The step ladder of claim 15, wherein the anchor mount extends away from the first and second plates in a first direction and each step mount further includes a rim that extends away from the first and second plates in an opposite second direction to define chamber means for receiving one end of the step associated with said step mount so that said step mount is located in a fixed position on said step.

23. The step ladder of claim 14, wherein the step is hollow and includes a horizontal top wall, a U-shaped base wall coupled to the horizontal top wall to form a hollow interior region therebetween, and a partition wall extending from the horizontal top wall to the U-shaped base wall and substantially bisecting the hollow interior region defined between the horizontal top wall and the U-shaped base wall to provide such step with a substantially B-shaped cross-sectional shape.

24. The step ladder of claim 23, wherein each step mount includes a first plate arranged to abut the first tubular member, a second plate arranged to abut a companion second tubular member, and a mount anchor positioned to lie between the first and second plates and extend into an anchor-receiving channel defined by the companion first and second tubular members and the web located between the companion first and second tubular members and wherein the partition wall is arranged to extend along and in alignment with the mount anchor of each step mount coupled to such step.

25. The step ladder of claim 24, wherein each of the web and the anchor mount is formed to include a fastener-receiving aperture, the fastener-receiving apertures are in alignment with one another, the fastener extends through the fastener-receiving apertures, and the step is formed to include means for mating with a distal portion of the fastener extending through said fastener-receiving apertures so that said step and step mount are anchored in a fixed position relative to said first and second tubular members.

26. A step ladder comprising

a frame including a left leg and a right leg and

a plurality of step units arranged to lie between the left and right legs, each step unit includes a step, a left step mount located between the left leg and a left end of the step, a left fastener arranged to couple the left step mount and the left end of the step to the left leg, a right step mount located between the right leg and a right end of the step, and a right fastener arranged to couple the right step mount and the right end of the step to the right leg, and wherein the step is hollow and includes a horizontal top wall, a U-shaped base wall coupled to the horizontal top wall to form a hollow interior region therebetween, and a partition wall extending from the horizontal top wall to the U-shaped base wall and substantially bisecting the hollow interior region defined between the horizontal top wall and the U-shaped base wall to provide such step with a substantially B-shaped cross-sectional shape.

27. The step ladder of claim 26, wherein each of the left and right legs includes spaced-apart first and second tubular members and a web located between and coupled to the first and second tubular members, the left step mount is arranged to abut the first and second tubular members of the left leg, and the right step mount is arranged to abut the first and second tubular members of the right leg.

28. The step ladder of claim 27, wherein the left step mount includes a first plate arranged to abut the first tubular member of the left leg, a second plate arranged to abut the second tubular member of the left leg, and a mount anchor positioned to lie between the first and second plates and extend into an anchor-receiving channel defined by the first and second tubular members of the left leg.

29. The step ladder of claim 28, wherein the partition wall of the step is arranged to extend along and in alignment with the mount anchor of the left step mount.

30. The step ladder of claim 28, wherein each of the web of the left leg and the mount anchor of the left step mount is formed to include an aperture receiving the left fastener therein and a distal end of the left fastener is coupled to the partition wall of the step to retain the step and the left step mount in fixed positions relative to the left leg.

31. The step ladder of claim 28, wherein the anchor mount extends away from the first and second plates in a first direction and the left step mount further includes a rim that extends away from the first and second plates in an opposite second direction to define chamber means for receiving the left end of the step so that the left step mount is located in a fixed position on the step.

32. The step ladder of claim 26, wherein a rear portion of the U-shaped base wall is coupled to a rear edge of the horizontal top wall and cooperates with the horizontal top wall to define an acute included angle therebetween.

33. The step ladder of claim 32, wherein the rear portion of the U-shaped base wall is positioned to lie in spaced-apart parallel relation to the partition wall.

34. The step ladder of claim 32, wherein a front portion of the U-shaped base wall is coupled to a front edge of the horizontal top wall and cooperates with the horizontal top wall to define an acute included angle therebetween.

35. The step ladder of claim 34, wherein the front and rear portions of the U-shaped base wall are arranged to diverge in a direction toward the horizontal top wall.

36. A step ladder comprising

a front frame portion including a left leg and a right leg, each of the left and right legs of the front frame portion including first and second tubular members and a front web located between and coupled to each of the first and second tubular members,

a rear frame portion mounted for movement relative to the front frame portion between an expanded position supporting the front frame portion in an inclined position and a collapsed position lying alongside the front frame portion, the rear frame portion including a left leg pivotably coupled to the left leg of the front frame portion and a right leg pivotably coupled to the right leg of the front frame portion, each of the left and right legs of the rear frame portion including third and fourth tubular members and a rear web located between and coupled to each of the third and fourth tubular members, and

a plurality of step units arranged to lie between the left and right legs of the front frame portion, each step unit being coupled to the left and right legs of the front frame portion to support said step unit in a fixed position relative to the left and right legs of the front frame portion.

37. The step ladder of claim 36, wherein a first of the step units includes a hollow step including a horizontal top wall, a U-shaped base wall coupled to the horizontal top wall to form a hollow interior region therebetween, and a partition wall extending through the hollow interior region from the horizontal top wall to the U-shaped base wall to provide such step with a substantially B-shaped cross-sectional shape.

38. The step ladder of claim 37, wherein the first of the step units further includes left step mount means for coupling a left end of the hollow step to the web of the left leg of the front frame portion and right step mount means for coupling a right end of the hollow step to the web of the right leg of the front frame portion.

39. The step ladder of claim 36, wherein each of the first, second, third, and fourth tubular members of the left legs of the front and rear frame portions include first, second, third, and fourth side walls arranged in series to define an interior region therebetween.

40. The step ladder of claim 39, wherein the first side walls of said first, second, third, and fourth tubular members lie in coextensive relation with a first reference plane, the second side walls of said first and second tubular members are coupled to the front web, the second side walls of said third and fourth tubular members are coupled to the rear web, the third side walls of said first and second tubular members lie in coextensive relation with a second reference plane that is oriented to cooperate with the first reference plane to define a first acute included angle therebetween, the third side walls of said third and fourth tubular members lie in coextensive relation with a fifth reference plane that is oriented to cooperate with the first reference plane to define a third acute included angle therebetween and to cooperate with the second reference plane to define an obtuse included angle therebetween.

41. The step ladder of claim 39, wherein each of the front and rear webs is oriented to lie in a single plane.

42. The step ladder of claim 39, wherein each of the front and rear webs is oriented to lie in offset relation to a central reference plane bisecting the second side walls of the first, second, third, and fourth tubular members.