Abstract: An adjustable clamping frame used in a vacuum forming machine comprising two longitudinal frame members disposed in spaced parallel relation to one another and two transverse frame members disposed in spaced parallel relation to one another. The two longitudinal frame members are perpendicular to the two transverse frame members. The longitudinal frame members have elongated slots for receiving the opposite ends of the two transverse frame members. The elongated slots permit selective sliding movement of the transverse frame members within the longitudinal frame members for varying the spacing between the transverse frame members in order to accommodate varying sizes of plastic sheets to be molded. The elongated slots also permit removal of each transverse frame member by rotation of each transverse frame member out of the elongated slots of the longitudinal frame members.

Abstract: An improved temperature sensing and controlling arrangement for incorporation in thermoplastic heat forming systems includes an infrared thermometer operative to sense the temperature of a plastic sheet during its heating and to produce a direct current output in linear proportion to the intensity to the radiation emitted by the sheet, an electrical relay assembly operative to receive the direct current from the thermometer and to energize and de-energize a relay when the value of the direct current is below or at or above a predetermined value corresponding to a predetermined maximum temperature to which the sheet is to be heated, and a programmable microprocessing sequencer operatively associated with the relay assembly and the heating oven to de-energize and energize the oven when the relay is energized and de-energized, respectively.

Abstract: A clamping frame for use in plastic forming apparatus which includes a plurality of tubular elements joined together to define an opening over which a sheet of plastic material is mounted with the edges of the plastic sheet being held against supporting surfaces of the tubular elements by clamps. Each tubular element is formed of a thermally conductive material and includes an interiorly disposed heating element located adjacent the supporting surfaces of the tubular element. The tubular elements include a plurality of interconnections to permit selective positioning of the tubular elements with respect to one another for varying the size of the opening defined thereby, and these interconnections also electrically connect the heating elements within the tubular elements at all adjusted positions thereof to form a closed electrical circuit which may be connected to an electrical source whereby the edges of the plastic sheet between the clamps and the tubular element supporting surfaces may be heated.

Abstract: A table for use in plastic forming machines, the table including a plurality of upstanding tubular support members arranged in a predetermined pattern, a plurality of alternately usable platform members, each such platform member being of a different size to support different vacuum molds and each being mountable on upstanding tubular supports at selected positions on the table. A plastic material clamping frame having readily adjustable side elements for varying the size of the clamping frame is arranged to be selectively positionable, at all variable sizes thereof, to thereby hold the edges of a sheet of plastic material along and beneath the edges of different vacuum forming molds mounted on a platform member supported by the tubular support members at the selected positions thereof.

Abstract: An adjustable clamping frame for clamping the peripheral edges of a sheet of plastic material during the plasticizing and vacuum forming thereof, such frame including a first pair of parallel side elements having clamping elements mounted thereon and being selectively adjustable toward and away from one another to vary the spacing therebetween, and a second pair of side elements selectively mountable in any of a plurality of facing slots spaced along the length of the first pair of side elements.

Abstract: A table for use in plastic forming machines, the table including a plurality of upstanding tubular support members arranged in a predetermined pattern, a plurality of alternately usable platform members, each such platform member being of a different size to support different vacuum molds and each being mountable on selected ones of the upstanding tubular supports. A plastic material clamping frame having readily adjustable side elements for varying the size of the clamping frame is arranged to be selectively positionable, at all variable sizes thereof, between selected tubular support members to thereby hold the edges of a sheet of plastic material along and beneath the edges of different vacuum forming molds mounted on a platform member supported by the tubular support members.