div class=trans-pagebuttonPage 1button div class=trans-image amp-img class=trans-thumb alt=Page 1: View - Compression springs Canada torsion springs … Example Design a torsion spring to counterbalance a trap door The door weighs 20 lb 907 kg and its width is 18 in 4572 src=https:reader030fdocumentsinreader030viewer20220204115ac051ab7f8b9a213f8bd682html5thumbnails1jpg width=142 height=106 layout=responsive amp-img divdivdiv class=trans-pagebuttonPage 2button div class=trans-image amp-img class=trans-thumb alt=Page 2: View - Compression springs Canada torsion springs … Example Design a torsion spring to counterbalance a trap door The door weighs 20 lb 907 kg and its width is 18 in 4572 src=https:reader030fdocumentsinreader030viewer20220204115ac051ab7f8b9a213f8bd682html5thumbnails2jpg width=142 height=106 layout=responsive amp-img divdivdiv class=trans-pagebuttonPage 3button div class=trans-image amp-img class=trans-thumb alt=Page 3: View - Compression springs Canada torsion springs … Example Design a torsion spring to counterbalance a trap door The door weighs 20 lb 907 kg and its width is 18 in 4572 src=https:reader030fdocumentsinreader030viewer20220204115ac051ab7f8b9a213f8bd682html5thumbnails3jpg width=142 height=106 layout=responsive amp-img divdivdiv class=trans-pagebuttonPage 4button div class=trans-image amp-img class=trans-thumb alt=Page 4: View - Compression springs Canada torsion springs … Example Design a torsion spring to counterbalance a trap door The door weighs 20 lb 907 kg and its width is 18 in 4572 src=https:reader030fdocumentsinreader030viewer20220204115ac051ab7f8b9a213f8bd682html5thumbnails4jpg width=142 height=106 layout=responsive amp-img divdiv