Funny you should ask...
The commonly know "see-saw" is considered a first-class lever.
A teeter-toter
playground equipment
The seesaw or teeter-totter is a lever with the fulcrum in the middle, and the merry-go-round is a wheel and axle.
There are several companies which makes this type of equipment. Playland Inc make some great playground furniture. Gametime is the lead manufacturer of commercial playground equipment.
The same safety standards go for indoor and outdoor playground equipment. Outdoor equipment is designed to be more durable.
The most important consideration when installing playground equipment is the finishing material.
There are no national stores which sell playground equipment for schools. You can get some items at Lowes and Home Depot but its not school playground quality.
There are several stores that sell playground equipment. Some stores sell wooden playground equipment like Lowes or Home Depot, or stores like Walmart sell the plastic or metal ones.
www.allplaydoesitall.com has customizable playground equipment. au.dir.yahoo.com/Business.../Playground_Equipment has a listing of business specializing in this field. You can get customized park playground equipment at www.allplaydoesitall.com. Another good website is www.equipment.net/list/playgroundequipment.htm.
A see-saw is a first class lever that can be found in playgrounds.
You should check out the safety before purchasing indoor playground equipment. You can read more at www.alibaba.com/importers/indoor-playground-importer.html
One can indeed buy personal playground equipment through Soft Play. One can also purchase playground equipment through Soft Play distributors in their home state.
swings