Double-hung tilting sash type window system

A window having an inside and outside, comprising:

• (a) a frame having at least two oppositely disposed side members, a top member and a bottom member;
• (b) a side jamb liner approximately parallel to and operably connected to each frame side member, the jamb liner having a front face and at least one jamb channel;
• (c) a sash having two oppositely disposed sides, the sash being slidably mounted in the frame and having a tilted position and an untilted position, the sash in the untilted position having the two sides parallel and proximate opposite frame side members;
• (d) a locking slide block slidably mounted within the jam channel for slidably and rotatably mounting the sash to the frame, the locking slide block having a means for retaining the sash, and a locking means adapted for selectively engaging the jamb channel and locking the block in a fixed position when the sash is in the tilted position;
• (e) a plough extending from the face of each jamb liner in the direction of the opposite frame side member, the plough having an inside facing side and an outside facing side, wherein the outside facing side has a projecting portion extending generally in the direction of the outside of the window;
• (f) a sash groove in each sash side for slidably mounting the sash in the frame by receiving adjacent ploughs when the sash is in the untilted position, the groove having a generally inside facing side and a generally outside facing side, wherein the inside facing side has a projecting portion projecting generally in the direction of the inside of the window forming an indentation;
• so that when the sash is in the untilted position the projection portion of the plough engages with the indentation formed by the projecting portion of the groove to resist inward displacement of the sash;
• (g) means for mounting the jamb liner for lateral displacement from a first position wherein the plough is engaged with the sash groove to a second position wherein the plough is at least partially retracted from the groove;
• (h) means for laterally displacing the jamb liner from the first position to the second position;
• and
• (i) a counterbalance operably connected to the frame having a counterbalance tab which includes a means for fastening the tab to the counterbalance, an elongated portion extending from the means for fastening, the elongated portion having a first end proximate the means for fastening and a second end opposite the first end, and a flange proximate the second end.