Abstract:
A plastic program card includes a plurality of projecting rows of plastic each having notches at selected locations. It is driven through a program unit having a different push-button switch aligned with each row of the card to be actuated by the notches therein to control different functions of the thermoforming machine. The temperature of the sheet of plastic, the positions of the moving parts of the thermoforming machine, and the position of the plastic being formed are sensed by other devices within the thermoforming machine and these devices control further operations of the machine and control the driving of the plastic program card through the program unit.
Abstract:
Articles are molded by heating a sheet of thermoformable material, stretching it during the heating of the sheet to prevent it from sagging, and then forming the heated material into the article. The apparatus includes a clamping frame on which is slidably mounted a series of spaced-apart clamping assemblies for holding the marginal edges of the sheet to position it in a planar configuration. The clamping assemblies are moved farther apart by means of a series of piston cylinder assemblies to expand the frame thereby stretching the heated sheet to maintain its coplanar configuration during the heating thereof. By controllably moving the clamping assemblies toward one another to contract the frame during the subsequent forming of the article, the wall thickness of the article is controlled.
Abstract:
To obtain a mixture of air and a combustible gas for burning, a first plurality of elongated infrared radiation gas burners forming a bottom section and a second plurality of elongated parallel infrared radiation gas burners forming a top section of an oven of a thermoforming machine communicate with four manifolds, with each of the burners in a lower section communicating with two manifolds through two different gas lines and with each of the burners in the upper section communicating with the other two manifolds through two different lines, one of the lines between each burner and the manifold including a manually adjustable valve for controlling, within a range, the flow of gas to the burner. Gas is provided to the manifolds through gas lines under the control of (1) venturi type gas mixers; (2) automatically controlled regulating valves; (3) manual valves; and (4) valves that close the gas line between cycles of the thermoforming machine to clear the lines with air, and, when an infrared photocell determines that the plastic sheet is too hot, to cool the plastic sheet by blowing air upon it.
Abstract:
The four pinions that are mounted to a platen and engage four vertical racks in the molding station to position the platen of a molding machine vertically are driven by two motors with each motor driving a shaft that is connected at one end to a speed reducer with which it drives one pinion and is connected at its other end to a transverse shaft through a bevel gear, the transverse shaft being connected to another speed reducer by which the second pinion is driven. With two motors driving high rpm shafts that extend close to the four pinions, the platen has a better weight distribution, greater efficiency, greater torque at the pinions, more accurate positioning, more accurate braking and a longer stroke.
Abstract:
TO REDUCE THE VIBRATING OF THE MOLDING MACHINE DURING A MOLDING OPERATION, THE FRAME OF THE MOLDING MACHINE INCLUDES TWO PARALLEL I BEAMS EXTENDING ACROSS THE TOP OF THE MACHINE FROM THE OUTER END OF THE MOLDING STATION TO THE OUTER END OF THE LOADING STATION WITH A ROTARY DRIVE SHAFT AND PLASTIC SHEET CARRYING ASSEMBLY BEING CENTRALLY MOUNTED WITH RESPECT TO THE I BEAMS FOR EASY ASSEMBLY AND REPLACEMENT. THE RECTANGULAR SHEET-HOLDING FRAMES OF THE ROTARY SHEET CARRYING ASSEMBLY ARE VERTICALLY SUPPORTED AT EACH END BY TURNBUCKLES CONNECTED TO TRUSSES BY WHICH THE HORIZONTAL ANGLE OF THE FRAMES IS ADJUSTED. TO PERMIT EASY ASSEMBLY OF THE DIES TO MOVABLE PLATENS WITHIN THE MOLDING STATION, THE MOVABLE PLATENS INCLUDE LONGITUDINALLY EXTENDING GROOVES ADAPTED TO RECEIVE T-BOLTS HAVING OUTWARDLY EXTENDING SHANKS WHEREBY THE BASE FOR THE DIES IS BOLTED TO THE PLATEN.