The Smart Ladder
 U.S. Patent #6,966,403 issued on November 22, 2005

Invented by Suresh Chandra

What is a Smart Ladder?

It is a regular ladder with electronic intelligence such that it sounds alarm when the ladder approaches an unstable state. The Smart Ladder is designed to prevent injuries due to sideways tipping. A working model was demonstrated at Wright State University's InventorFest 2005. Smart Ladder

Benefits and Cost:

  1. Reducing injuries. 

  2. Enhancing productivity by letting climber know the maximum safe distance one can reach out.

  3. A smart ladder may not cost more than a "dumb" ladder if savings in liability insurance in the U.S. offsets the cost of electronics.

Magnitude of ladder injury problem in U.S.:

Every year in the U.S.

  • 500,000 people get hurt by ladders.

  • Of these, 164,000 people require emergency treatment, according
    to U.S. Consumer Products Safety Commission.

  • About 30,000 people are disabled.

  • About 300 people die from ladder injuries.

  • The economic cost in the U.S. is estimated to be $11 billion annually
    for work loss, medical, legal, liability and pain-and-suffering expenses.

Note that only a faction of the ladder injuries  occur because of sideways tipping. Other causes include backward sliding of the ladder, slipping off a ladder rung, losing grip, etc.

Physics behind ladder tipping:

  1. Ladder will tip sideways if a vertical line from the center of gravity of the ladder plus the climber crosses past one of the legs of the ladder.

  2. The sideways tipping instability can occur two ways: (a) When the climber reaches too far sideways, and (b) the ladder is placed on an uneven ground tilting one way or the other. In the second case the ladder may be stable initially, but becomes gradually unstable as the climber climbs up the ladder.

  3. With a "dumb" ladder, there is no indication of any hazardous condition until it is too late.

  4. Since (nearly) all the weight of the ladder and climber is supported by the ladder's feet of the, monitoring the weight on each leg provides a means to knowing the degree of instability.

What are the ladder smarts composed of?

  1. Weight sensors attached to ladder feet.

  2. Electronics to monitor safety condition.

  3. An audio &/or visual alarm system to feedback to the climber about the safety condition (safe, requiring caution, and dangerous conditions). Alarm may be wireless, to be worn like a pager

  4. Optional addition: a counterbalancing weight, adjustable manually or automatically.

Smart ladder sensors and electronics in action
SAFE condition CAUTION needed DANGEROUS condition
Different views of controller box showing lights, buzzers, 9V battery

 

Comparing standard and Smart Ladders
Regular Ladder
 		 Smart Ladder
 
1. No monitoring of hazardous condition
 		 1. Continuous monitoring for hazardous condition
 
2. You find out about dangerous condition only when too late. No alarm. 2. Alarms sound when situation requires caution or is dangerous
3. Low productivity because climber acts too cautious 3. Higher productivity because climber will reach maximum safe distance
4. High rates of injury because climbers reach out too far 4. Low rates of injury because climber gets warned when reaching out too far
5. High cost of insurance that must be folded into the ladder price. 5. Potentially lower ladder price because of lower insurance cost. 

Demonstration at Wright State University InventorFest:

Top

More Enhancements:

Wireless Alarm

Counterbalance

Counter Weight

 

Are there any negatives?

Sure, -- for hospital business, doctors and insurance companies. Also battery costs.

Inventor, Suresh Chandra, is a physicist, with 11 U.S. patents in the field of lasers and optics. The smart ladder is his first patent in a consumer area.

Suresh's Home Page

Top                                        updated January 09, Dec 2006