Abstract: A thermoforming apparatus includes a female die and a movable plug for thermoforming a softened thermoplastic resin sheet. The female die includes a rim forming recess in the shape of a bowl-shaped recess, communicating with a bottom opening and forming a bottom wall of the bowl, an outer wall, a bottom wall and an inner wall of a rim of the bottom, and a bottom plate movable forward and backward relative to the rim forming recess. The softened thermoplastic resin sheet is thrust by the plug while the bottom plate is held at a first stop position. The thermoplastic resin sheet is brought into contact with an inner circumferential surface of the bowl-shaped recess and then the bottom plate is moved to a second stop position so that a rim is formed.

Abstract: A bowl-shaped container has a rim of a bottom and the rim is hollow. The container is made of a thermoplastic resin sheet, and wherein the hollow rim is formed by folding the thermoplastic resin sheet including a side wall surface and a bottom wall surface continuous with each other into the shape of a bag and by welding the sheet at the wall surface sides. The body of the container may have a plurality of ribs protruding outward and no slit-like recess in its inner circumferential face. The ribs are formed by thrusting the thermoplastic resin sheet into a plurality of grooves formed in a forming female die.

Abstract: Apparatus and process for trimming articles molded on a plastic sheet and successively fed from a forming machine. A carriage receives the article to be held thereunder by vacuum and is moved in a trimming zone, where a pair of longitudinal cutter devices, each having a stationary blade and an angularly movable blade, are horizontally moved together from respective retreated positions for longitudinal cutting. Then, a front transverse cutter device having similar pair of blades is raised up from a retreated position for transverse cutting and then a rear transverse cutter device is similarly operated.

Abstract: A device for gripping and pulling a length of thermoplastic sheet softened to be moldingly formed at the front and rear edges, which are otherwise inevitably made to be concave, so as to hold edges substantially straight. The device uses at least two pairs of lower and upper gripping members arranged to be vertically movable so as to grip the above front and rear edges. Two pairs of pull levers each cooperating with one of the pair of lower and upper gripping members operate so as to grip the front and rear edges in advance of the gripping by the gripping members and pull to straighten the concaved edges which are then gripped by the gripping members.

Abstract: A device for centering plastic webs automatically fed thereon one by one so as to feed it to a pair of cramp chains to be correctly gripped thereby at the opposite side edges. This comprises a bed consisting of a central frame and longitidinal as well as transverse arms respectively extended in opposite directions from the central frame for supporting the web of varied size. A plurality of pairs of centering members, each having an upwardly projected pin, are oppositely arranged and adapted to move toward and apart with each other so as to abut on the longitudinal and transverse side edges of web on the table with said pin for centering. It is preferable and sufficient to move said centering members by means of a belt and pulleys for treating a light web.

Abstract: Apparatus for longitudinally and transversely trimming articles moldingly formed on plastic sheet which is brought by means of a pair of clamp chains between longitudinally movable pointed tip knives and longitudinally extended holder members as well as transversely movable pointed tip knives and transversely extended holder member respectively held in retracted position and then trimmed by moving said knives and holder members to forwarded position and by moving said knives. Said sheet is formed in advance with transversely and longitudinally extended ridges so that said moving knives cannot sever the sheet at said ridges, whereby trimmed articles fall down by gravity and waste portion kept in one piece is brought out by said clamp chains to be collected.

Abstract: Plastic web to be fed into opposite dies for forming articles must be heated and softened by heater means in front of the forming machine, even if said machine is combined with an extruder supplying said plastic web. The invention provides a radiant heater adapted to be sensitively responsive to manual or automatic control so as to more suitably regulate a temperature of the plastic web in comparison with the conventional heater comprising quartz tubes each having a coiled nichrome wire. The heater of the invention comprises an extended thin nichrome plate arranged in zig-zag on a table plate.

Abstract: Apparatus for longitudinally and transversely trimming articles moldingly formed on plastic sheet which is brought by means of a pair of clamp chains between longitudinally movable pointed tip knives and longitudinally extended holder members as well as transversely movable pointed tip knives and transversely extended holder members respectively held in retracted position and then trimmed by moving said knives and holder members to forwarded position and by moving said knives. Trimmed articles fall down by gravity and the waste portion is kept in one piece and brought out by said clamp chains to be collected.

Abstract: Apparatus for severing thermoplastic sheet continuously produced from an extruder and successively feeding a length of plastic web to an intermittently operated forming machine. The extruded and cooled sheet drops from a roller down on a belt conveyor running at the same speed as the extrusion rate and is transferred towards the forming machine by a pair of clamp chains. The chains extend from sprocket wheels located in the range of the belt conveyor and are adapted to run intermittently at a speed higher than the extrusion rate and in accordance with the operation of the forming operation. The running speed of the conveyor belt can be increased to the higher speed when the falling sheet has been severed thereabove in the suspended position so that the severed plastic web is grasped by the clamp chains to be fed to the shaping station of the forming machine.

Abstract: Improvement for forming machine by preventing the softened thermoplastic material sheet from dangling and unevenly stretching between a pair of clamp chains, which are extended on a plurality of sprocket wheels to be intermittently driven so that the upper run thereof may receive and keep the sheet stationary in the waiting zone of the machine when the male and female die boxes are contacted for molding and then feeding the sheet between the separated die boxes. The improvement comprises a plurality of longitudinally elongated supporter means such as endless strings or a series of small discs arranged longitudinally close with each other in said waiting zone, and a plurality of bores formed in the lower die box for blowing air in the molding zone.

Abstract: Apparatus for forming articles from the thermoplastic sheet is combined with a plastic sheet extruder for the purpose of producing articles efficiently and economically. Such forming machine is operated intermittently and periodically while the extruder continuously extrudes the plastic sheet so that it is necessary to provide any countermeasure for settling the discrepancy to be caused in the sheet movement. The countermeasure is provided by making the extruder longitudinally movable so that when the forming machine is in its molding operation where the opposed two dies thereof are engaged the extruder is retracted so as to receive the extruded plastic sheet on the carrier extended between the two for supplying the length of the plastic sheet to the forming machine in its unoperated position where the opposed dies are separated for receiving said supply therebetween.