Piston for cartridges of building sealant has domed top and vertical walls and peripheral ribs near point where these join, top rib curving outwards and having slots around it and lower rib being vertical and enclosing pocket with it

摘要

The piston for cartridges of building sealant has a domed top (12) and vertical walls (14). Two peripheral ribs (16, 17) are mounted near the point where these join. The top rib is curved outwards and has slots (54) spaced around it. The lower rib is vertical and encloses a pocket (19) with the upper rib. An independent claim is included for a cartridge fitted with the piston.