and operation of toggle clamp mechanism 24 may be best understood by referring to fig2 4 and 5 fig2 illustrates the toggle clamp mechanism 24 in an open position in which the short metal bars 23 are in a downward retracted relationship relative to the lower vertical bars 12 in this position the clamp pad 17 rests on the upper surface or sill a of a window frame and the upper clamp pads 25 are positioned below the lower surface c of the window frame the window is a conventional horizontal sliding window with an upper track 64 and a lower track 63 with one or two sliding glass panels 44 and 46 as shown in fig2 and 10 each of the plates 16 and 21 support coextensive window clamps 22 formed of sheet metal each clamp 22 has a flat web that projects to the inside edges of window tracks 64 and 63 the clamp 22 is bent into a channel 37 having a width sufficient to receive the inside flange of each track 64 and 63 as shown in fig1 the opposite ends of each channel 37 are chamfered preferably at 45 u00b0 to prevent binding of the sliding window panels as shown in fig2 4 and 5 the toggle clamp mechanism 24 includes a channel frame section 26 which is fastened to an outer vertical surface of a lower rigid vertical bar 12a the toggle clamp mechanism 24 also includes a multi component lever mechanism 27 which is vertically slidably attached to the channel frame section 26 and pivotally attached to a short vertically disposed metal.