Method of producing precast concrete panels with built-in outer sash frames

A method of producing a precast concrete panel with a built-in outer frame of a sash window or the like, wherein the outer sash frame has lowermost and uppermost flanges, said method comprising the steps of:

• a. providing a form which has a bottom, side panels on said bottom for defining the outer periphery of the concrete panel, and raised rectangular sill-defining rest means arranged internally of the side panels on the bottom for defining the inner periphery of the concrete panel;
• b. arranging a plurality of clamping fixtures in spaced positions on the inside of the rest means, each fixture including lower and upper holders arranged to face the raised rest means for downwardly clamping the lowermost and uppermost flanges, respectively;
• c. placing the outer sash frame with the lowermost flange to rest on the top of the rest means in spaced relation to the bottom of the form;
• d. clamping the outer sash frame downwardly onto the rest means by means of the lower and upper holders acting downwardly and independently of each other on the sash frame flanges remotely from its corners;
• e. pouring concrete into a space bounded by the outer sash frame and the bottom, side panels and rest means of the form;
• f. curing the concrete;
• and
• g. after releasing the clamping fixtures, withdrawing the precast concrete panel with the built-in outer sash frame from the form.