knee pad 40 can be snapped on to bars 224 at various positions frame support 44 is adapted to rest on a flat surface such as the floor and to receive cross member 56 of frame 12 support 44 provides an opening 210 along its length sized to receive cross member 56 of frame 12 a wrench 300 as shown in fig9 is provided with gate 10 wrench 300 has an open end 302 with an inner opening 304 shaped to receive knob 176 fig2 and 7 and to engage outer surface 208 fig7 of knob 176 so that knob 176 can be turned using wrench 300 wrench 300 has a flat handle 306 of a thickness 308 referring to fig1 7 pieces of gate 10 can be made as follows frame 12 and barrier 46 are welded of steel in the configurations shown foot pedal 16 bracket 18 foot pedal support 42 pad 40 and frame support 44 are injection molded acrylonitrile butadiene styrene abs holes and slots provided by frame 12 can be machined after frame 12 is injection molded or can be formed as part of the injection molding caps 172 knobs 176 and end pieces 180 are also molded abs springs 36 126 and 146 are made of steel as well as rivets 80 and 84 nut 174 and rod 178 gate 10 can be assembled as follows linkage 34 is inserted into interior 96 of spring 36 linkage 34 and spring 36 are inserted into opening 76 of arm 54 and positioned by inserting pins.