Smart ladder

• US 6,966,403 B1
• Filed: 02/09/2004
• Issued: 11/22/2005
• Est. Priority Date: 02/10/2003
• Status: Active Grant

• Current Assignee: Suresh Chandra
• Original Assignee: Suresh Chandra
• Inventors: Chandra, Suresh
• Primary Examiner(s): THOMPSON, HUGH B
• Application Number:
  US10/774,736
• Time in Patent Office: 652 Days
• Field of Search: 182/18, 182/129, 182/94, 340/666, 340/665, 340/323.R
• US Class Current: 182/18
• CPC Class Codes: E06C 7/003 Indicating devices, e.g. user warnings or inclinators

Abstract

A ladder with a tip warning system. The ladder is configured to be carried by at least one human user, and includes a plurality of legs with rungs disposed between the legs, and a tip warning system. The tip warning system includes an audio alarm and a visual alarm, a power source, one or more weight sensors and a controller signally coupled to the weight sensors. Imbalance conditions, such as due to the weight of a climber extending beyond the footprint of the ladder, generate an imbalance signal that activates the tip warning system to provide notorious indicia of such condition to the user. In one form, a counterweight activated by the imbalance signal may be incorporated to correct dangerous operating conditions.

Claims

1. A ladder configured to be carried by at least one human user, said ladder comprising:

a plurality of legs, each defined by a first end and a second end;

a plurality of rungs disposed between said legs; and

a tip warning system comprising;

at least one of an audio alarm or a visual alarm;

a power source to energize said at least one alarm;

a plurality of weight sensors, each cooperative with a corresponding one of said plurality of legs or rungs; and

a controller signally coupled to said weight sensors such that upon generation of a weight signal in each of said weight sensors, said controller compares differences in said signals to determine a measure of imbalance in said ladder and provide, upon attainment of a measure of said imbalance that exceeds a predetermined signal threshold, notorious indicia to said human user through said at least one alarm.

2. The ladder of claim 1, wherein said plurality of weight sensors are disposed adjacent said first end.

3. The ladder of claim 2, wherein said plurality of weight sensors are disposed beneath said first end.

4. The ladder of claim 1, wherein said measure of imbalance comprises a ratio of said differences in said sensed weight signals divided by a sum of said sensed weight signals.

5. The ladder of claim 1, wherein said controller comprises analog comparators.

6. The ladder of claim 1, wherein said controller comprises at least one digital microprocessor.

7. The ladder of claim 1, further comprising a movable counterbalancing weight coupled to said ladder, said counterbalancing weight responsive to said controller.

8. The ladder of claim 7, wherein said counterbalancing weight is mechanically adjustable.

9. The ladder of claim 7, wherein said counterbalancing weight is manually adjustable.

10. The ladder of claim 1, wherein said power source comprises a battery.

11. The ladder of claim 1, wherein said power source comprises a solar cell.

12. The ladder of claim 1, wherein said ladder is a stepladder.

13. The ladder of claim 1, wherein said at least one alarm comprises said audio alarm and said visual alarm.

14. The ladder of claim 13, wherein at least one of said alarms is disposed adjacent said second end.

15. The ladder of claim 14, wherein said visual alarm comprises at least one light.

16. The ladder of claim 15, wherein said at least one light comprises a plurality of lights.

17. The ladder of claim 16, wherein each of said plurality of lights corresponds to particular ladder safety category.

18. The ladder of claim 17, wherein said plurality of lights comprise:

a first light to indicate at least one of system operational status or a first of said ladder safety category;

a second light to indicate a second of said ladder safety category; and

a third light to indicate a third of said ladder safety category.

19. The ladder of claim 14, wherein said visual alarm comprises at least one display.

20. The ladder of claim 1, wherein said at least one alarm comprises said audio alarm.

21. The ladder of claim 20, wherein said audio alarm comprises a buzzer.

22. The ladder of claim 20, wherein said audio alarm is configured to vary an acoustic output that corresponds to particular ladder safety category.

23. The ladder of claim 22, wherein said varied acoustic output comprises:

a first sound to indicate at least one of system operational status or a first of said ladder safety category;

a second sound to indicate a second of said ladder safety category; and

a third sound to indicate a third of said ladder safety category.

24. The ladder of claim 23, wherein said first, second and third sounds comprise tones of successively higher frequency, respectively.

25. The ladder of claim 20, wherein said audio alarm comprises a prerecorded voice warning.

26. The ladder of claim 1, wherein said plurality of legs comprises no more than two legs.

27. The ladder of claim 1, wherein said ladder is an extension ladder.

28. A method of using a ladder, said method comprising:

configuring a ladder to comprise;

a plurality of legs;

a plurality of rungs disposed between said legs; and

a tip warning system comprising;

an audio alarm and a visual alarm;

a power source to energize at least said audio and visual alarms;

a plurality of weight sensors, each coupled to a respective one of said plurality of legs or rungs; and

a controller signally coupled to said weight sensors such that upon attainment of a predetermined signal threshold based on a difference in measured signals from said weight sensors, said tip warning system provides notorious indicia to a climber through at least one of said alarms;

placing said tip warning system in an operational condition;

placing said ladder against a ladder engaging surface;

climbing said ladder such that indicia is provided to said climber thereof to indicate at least one of an operational status or a ladder safety category, said ladder safety category comprising at least a first ladder safety category indicative of no imminent tipping and a second ladder safety category indicative of a possible tipping condition.

29. The method of claim 28, wherein said plurality of weight sensors are, each cooperative with a corresponding one of said plurality of legs or rungs such that upon generation of a weight signal in each of said weight sensors, said controller compares differences in said signals to determine a measure of imbalance in said ladder and provide, upon attainment of a measure of said imbalance that exceeds said predetermined signal threshold, said notorious indicia.

30. The method of claim 29, wherein said measure of imbalance comprises calculating a ratio of said sensed weight signal differences divided by a sensed weight sum.

31. The method of claim 28, wherein said plurality of legs comprises no more than two legs.

32. A tip-sensing ladder comprising:

a plurality of legs defined by a first end and a second end;

a plurality of rungs disposed between said legs to define a climbing path between said first and second ends; and

a tip warning system, said system comprising;

a plurality of weight sensors, each cooperative with a corresponding one of said plurality of legs or rungs;

a controller signally coupled to said weight sensors;

a plurality of alarms comprising an audio alarm and a visual alarm, said alarms responsive to said controller such that upon generation of a weight signal in each of said weight sensors, said controller compares differences in said signals to determine a measure of imbalance in said ladder and provide, upon attainment of a measure of said imbalance that exceeds a predetermined signal threshold, notorious indicia to a user through said at least one alarm; and

a power source to energize at least said plurality of alarms.