Construction
Hockey helmets grip the head from inside by cupping the back of head, or the occipital protuberance. Helmet manufacturers will have a chart that relates their helmet sizes to head measurements.
Most helmets have tool-free adjustments, but on older models, the helmet size is adjusted by loosening the screws on the side to slide the front portion forward or back.
The shell of a hockey helmet is made of a substance called vinyl nitrile that disperses force from the point of contact, while the liner may be made of either vinyl nitrile foam or expanded polypropylene foam to absorbs the energy, to reduce the chances of concussion.
Read more about this topic: Hockey Helmet
Famous quotes containing the word construction:
“The construction of life is at present in the power of facts far more than convictions.”
—Walter Benjamin (1892–1940)
“Striving toward a goal puts a more pleasing construction on our advance toward death.”
—Mason Cooley (b. 1927)
“There is, I think, no point in the philosophy of progressive education which is sounder than its emphasis upon the importance of the participation of the learner in the formation of the purposes which direct his activities in the learning process, just as there is no defect in traditional education greater than its failure to secure the active cooperation of the pupil in construction of the purposes involved in his studying.”
—John Dewey (1859–1952)