Sleeping pad
From Wikipedia, the free encyclopedia
In camping, a ground pad, sleeping pad, sleeping mat or roll mat is a simple device often used in conjunction with a sleeping bag. Its purpose is to provide padding and thermal insulation.
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[edit] Design
All types currently available use air as their primary form of insulation
[edit] Inflating Types
[edit] Manually Inflated
Closely related to the air mattress a pad of this type requires an external pressure source to inflate, typically in the form of a pump or by blowing orally. Convection of the air inside the mattress reduces the amount of insulation it provides and more complicated mattresses include methods to reduce this by either partitioning the internal cavities, or by filling the cavities with material to trap the air such as down feathers or synthetic insulation.
[edit] Self Inflating
An extension on the conventional manually inflated mattress this type is capable of self-inflation due to the open-cell foam that fills the internal cavity. For many years this design was protected by various patents held by Cascade Designs [1] and they were an unusual and premium item. But since these patents expired many other manufacturers are now producing this type of mattress and they are now commonplace.
[edit] Solid Types
Closed cell foam is used to produce simple mats that do not require any inflation. These have the advantage of not being prone to punctures. Variations include textured or shaped foam to increase the unrolled volume and/or change the stiffness of the mattress. This can also be used to trap the air within ridges or an egg-carton type of texture, as is the case in the Therm-a-Rest RidgeRest and Z-Lite, respectively.
[edit] References
- ^ Lea et al. 1979. Method of making a self-inflating air mattress. 4,149,919.
