the driveline 16 rotatably drives a collar 23 attached to the collar is a core member 25 which is configured to have a manual turning knob 26 a bearing portion 28 and a securement head 30 the securement head 30 is cylindrical and has opposing configured slots 32 a housing 34 includes an upper cover 36 mounted to the bearing portion 28 of the core member 25 and is slideable rotatably and axially on said bearing portion as permitted by knob 26 and shoulders 40 a spool 42 see also fig3 and 5 is mounted to the securement head 30 the spool includes upper and lower flanges 44 46 and a center or dividing flange 48 all radiating from a cylinder 50 the spool 42 has a tubular post 52 spanning the center of the cylinder 50 and as will be explained in a later section is extended along the dividing flange 48 as indicated in fig2 b the post 52 in assembled relation extends through the securement head 30 as permitted by the configured slots 32 and accordingly as the securement head is rotated by driveline 16 that rotation is transmitted to spool 42 via the post 52 a bottom portion 54 of.