초록 ▼

A piston for a pressure-dispensing container such as a cartridge for an extrusion gun has its closure panel formed of a central portion (34) arranged to receive the applied extrusion forces, and an annular and frustoconical outer portion (40) arranged to transmit the extrusion forces to the piston s

A piston for a pressure-dispensing container such as a cartridge for an extrusion gun has its closure panel formed of a central portion (34) arranged to receive the applied extrusion forces, and an annular and frustoconical outer portion (40) arranged to transmit the extrusion forces to the piston skirt (30) with an outwardly directed component by which the skirt is radially expanded to make firm sealing engagement with the container bore. The central portion is rigid so as to withstand the extrusion forces without any substantial distortion; the outer portion acts as a substantially rigid annular strut, notches (44) localizing any bending movements to the junctions of the outer portion with the central portion and with the skirt.

대표청구항 ▼

A thermoplastics piston for a pressure-dispensing container, which comprises a closure panel, and a tubular skirt which extends generally in a backward direction from integral attachment to the closure panel periphery and has an external surface which surrounds said integral attachment of said skirt

A thermoplastics piston for a pressure-dispensing container, which comprises a closure panel, and a tubular skirt which extends generally in a backward direction from integral attachment to the closure panel periphery and has an external surface which surrounds said integral attachment of said skirt with said closure panel in axial correspondence therewith and which is adapted to provide sealing and guidance for the piston by engagement with the bore of a said container in which said piston is received, wherein said closure panel has a central portion for receiving axially directed extrusion forces imposed on the piston for dispensing product from said container, and an annular portion connecting said central portion peripherally to said skirt, said central portion having a front face for contact with the product and being rigid so as to withstand said axially imposed extrusion forces and the resultant reaction forces of the product without any substantial distortion thereof, said annular portion having a dimension radially of said piston substantially less than the corresponding dimension of said central portion, and said annular portion being inclined and extending forwardly and outwardly towards said skirt so as to transmit the said extrusion forces to said skirt with a radially outward component by which said skirt may be expanded to bring its said external surface into sealing engagement with said container.