be used to bias the second arm 130 with respect to the first arm 120 however with this arrangement the bias that is applied by torsion spring 340 is applied directly to arms 120 and 130 whereas for spring 140 the bias is applied through the rivet 150 and its connection to the first arm 120 as seen in fig2 for catch assembly 101 and release assembly 201 the hook portion 341 h of the first leg 341 of torsion spring 340 may wrap around the first arm 120 in proximity to its stop 125 while the hook portion 342 h of the second leg 342 may wrap around the second arm 130 when the first arm 120 and second arm 130 are extended by opening of the sash the torsion spring is elastically deformed and as seen in fig2 the first and second legs 341 and 342 of the spring 340 being so deformed apply a biasing force to the arms 120 and 130 here again once the release assembly 201 no longer has its hook secured within the opening 135 of the second arm the spring 340 will bias the two arms to rotate toward each other until the side of the second arm contacts stop 125 as seen in fig2 for release assembly 201 the hook member used therein may take a slightly different shape.