ES376554A1 - Apparatus for making hollow plastic articles from thermoplastic sheet material - Google Patents

Abstract

False bottomed containers are made by first drawing a heat-softened thermoplastic sheet into a cavity 3, the base of which is defined by transversely reciprocable elements 2 and a punch 4 around the upper end of which are slidably located a series of concentric sleeves 7. The punch and sleeves are then raised to the position shown in Fig. 2 to move the bottom of the container formed by the drawing operation upwardly and to produce a downwardly extending divergent skirt between the upper surfaces of the sleeves and the inner surfaces of the elements 2. The sleeves 7 are supported in their lowest positions by three stepped segments 6 equiangularly located around the cavity 5 which guides the punch and are sequentially raised starting with the innermost, to their operative positions by three stepped segments 8 on the punch, the segments 8 being received between the segments 6 (see Figs. 3 and 4, not shown). The uppermost position of the sleeves is determined by a rod fixed to the tool member 1 and received in an axial slot in the sleeves (see Fig. 6 not shown) and the sleeves are returned to their lowest positions after the forming operation by a pin carried by the punch (see Fig. 5, not shown). The initial forming operation may be a plugassisted blow or vacuum forming operation. (For Figures see next page.)