Differential pressure forming machine with variable mold closed cycle
First Claim
1. In a thermoforming machine having a frame;
- a pair of mold carrying platens mounted on said frame for movement toward and away from each other between a mold open and a mold closed position, and motor driven means including cam and cam follower means operable when driven to cyclically drive said platens between said mold open and mold closed position, the improvement wherein said motor driven cam and cam follower means comprises a cam for each platen mounted on said frame for rotation about an axis, each cam having a dwell portion of given angular extent lying at a constant radius from the axis about which it rotates, said follower means including a cam follower for each platen engaged with each cam and operable to maintain the mold platen it drives in mold closed position when the cam follower is engaged with the dwell portion of its cam, variable speed motor means for driving said cams in rotation, and control means for selectively controlling the speed of said motor means during that portion of the rotary cycle of said cams when said cam followers are engaged with said dwell portions to thereby adjustably vary the times during which said mold platens are held in said mold closed position.
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Accused Products
Abstract
A thermoforming machine having opposed mold platens includes a linkage system driven in cyclic movement by rotary cam mechanism to cyclically shift the platens between their open and closed position. The cam mechanism is driven by a variable speed motor which is controlled in a manner such that the rotary speed of the cam mechanism during different portions of a cam revolution may be set to a speed which is different than the rotary speed of the cam mechanism during other portions of each revolution. By adjusting the speed differential or by adjusting the angular extent of that portion of a revolution of the cam mechanism over which the different speed is maintained the time duration of any chosen portion of the cycle may be adjusted independently of the time duration of other portions of the cycle.
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Citations
30 Claims
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1. In a thermoforming machine having a frame;
- a pair of mold carrying platens mounted on said frame for movement toward and away from each other between a mold open and a mold closed position, and motor driven means including cam and cam follower means operable when driven to cyclically drive said platens between said mold open and mold closed position, the improvement wherein said motor driven cam and cam follower means comprises a cam for each platen mounted on said frame for rotation about an axis, each cam having a dwell portion of given angular extent lying at a constant radius from the axis about which it rotates, said follower means including a cam follower for each platen engaged with each cam and operable to maintain the mold platen it drives in mold closed position when the cam follower is engaged with the dwell portion of its cam, variable speed motor means for driving said cams in rotation, and control means for selectively controlling the speed of said motor means during that portion of the rotary cycle of said cams when said cam followers are engaged with said dwell portions to thereby adjustably vary the times during which said mold platens are held in said mold closed position.
- View Dependent Claims (2, 30)
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3. In a thermoforming machine having a frame, a pair of mold carrying platens mounted on said frame for movement toward and away from each other between a mold open and a mold closed position, and variable speed drive means for driving each of said platens in intermittent motion through a cycle wherein each of said platens are shifted from said mold open position to said mold closed position and subsequently returned to said mold open position;
- the improvement comprising control means operable for varying the speed of drive of said drive means driving each platen during said cycle to cause said drive means to drive each platen at different speeds during different portions of the same cycle.
- View Dependent Claims (4)
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5. In a thermoforming machine having a frame, a pair of mold carrying platens mounted on said frame for movement toward and away from each other between a mold open and a mold closed position, and a motor operable when driven to cyclically drive said platens between said mold open and mold closed position, the improvement wherein drive elements driven by said motor are connected with each of said platens and are operable to maintain each of said mold platens in mold closed position during a dwell period, and control means is provided for varying the speed of said motor during a portion of the cycle of said drive elements for each platen which includes the time when each platen is in mold closed position.
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6. A method of operating a thermoforming machine having a pair of mold carrying platens mounted on a frame for movement toward and away from each other between a mold open and a mold closed position, a motor operable when driven to cyclically drive said platens between said mold open and mold closed position, and drive elements driven by said motor connected with each of said platens and operable to maintain each of said mold platens in mold closed position during a dwell period, comprising varying the speed of drive of said motor during a portion of the cycle of said drive elements for each platen which includes the time when each platen is in mold closed position.
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7. In a differential pressure thermoforming machine having a frame, a pair of mold carrying platens mounted on said frame for relative movement in which at least one moves between a mold open and a mold closed position;
- mating molds carried by said platens; and
motor driven means including cam mechanism and cam follower means connected to and operable when driven to cyclically drive at least one of said platens between said mold open and mold closed position;
the improvement wherein said motor driven cam mechanism and cam follower means comprises at least one cam mounted on said frame for rotation about a first axis and having a dwell portion of given angular extent lying at a constant radius from said axis, said follower means including a cam follower engaged with said cam and operable to drive said platen through a cycle from mold open to mold closed position and back to said mold open position in which it maintains at least one of said mold platens in said mold closed position when said cam follower is engaged with said dwell portion of said cam, and a motor assembly having control means for driving said cam continuously in rotation about said axis, and adapted for driving it at a different constant speed than it drives the cam in another portion of said cycle, during at least some of that portion of the rotary cycle of said cam when said cam follower is engaged with said dwell portion. - View Dependent Claims (8, 9, 10, 16)
- mating molds carried by said platens; and
- 11. In a thermoforming machine having a frame, a mold and platen assembly mounted on said frame and including a pair of mating molds mounted for relative movement between a mold open and a mold closed position, and a continuously driven motor operable when driven to cyclically drive said assembly and to effect the mold open and mold closed positions, the improvement wherein drive elements driven by said motor in continuously consecutive cycles are connected with said assembly and operable to drive said assembly through consecutive cycles effecting said relative movement and in which said molds are maintained in said mold closed position during a dwell period, and control means is provided for varying the speed of revolution of said motor during selected portions of the same cycle of the assembly to drive the motor at a different speed during a portion of each cycle which includes at least part of the dwell period.
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17. A thermoforming machine having a frame;
- a mold and platen assembly mounted on said frame and including a pair of mating molds, at least one being mounted for movement between a mold open and a mold closed position;
a drive motor;
driving elements, driven by said motor, connected with said one mold, said motor being operable when driven to cyclically drive said one mold relatively between mold open and mold closed position, and operable to maintain said one mold in said mold closed position during a dwell period, and control means for varying the speed of revolution of said motor during each cycle of said drive elements and driving said one mold at predetermined different speeds during each cycle from mold open to mold closed position and back. - View Dependent Claims (18, 19, 20, 21)
- a mold and platen assembly mounted on said frame and including a pair of mating molds, at least one being mounted for movement between a mold open and a mold closed position;
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22. A thermoforming machine having a frame, a mold and platen assembly mounted on said frame and including a pair of mating molds mounted for relative movement between a mold open and a mold closed position;
- a continuously driven, rotary hydraulic motor, operable when driven to drive said assembly to effect the mold open and mold closed positions;
drive elements, driven by said motor, connected with said assembly and operable to drive said assembly through consecutive cycles effecting said relative movement and in which said molds are maintained in said mold closed position during a dwell period;
a hydraulic system including a pump connected with the motor; and
control means operable to vary the output of the pump during selected portions of the same cycle of the assembly to drive the motor at a different speed during a portion of each cycle of the assembly which includes a portion of the dwell period. - View Dependent Claims (23, 24, 25, 26, 27, 28)
- a continuously driven, rotary hydraulic motor, operable when driven to drive said assembly to effect the mold open and mold closed positions;
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29. In a thermoforming machine having a frame, a mold and platen assembly mounted on said frame and including a pair of mating molds mounted for relative movement between a mold open and a mold closed position;
- a continuously driven, rotary motor, operable when driven to drive said assembly to effect the mold open and mold closed positions;
drive elements driven by said motor, connected with said assembly and operable to drive said assembly through consecutive cycles effecting said relative movement and in which said molds are maintained in said mold closed position during a dwell period;
the improvement wherein a variable input energy transmission system is provided to drive said motor at at least two different constant speeds; and
control means, comprising speed setting means operable in a first position to vary the energy input from said energy transmission system to said motor to drive it at a first constant speed and operable in a second position to vary the energy input from said energy transmission system to said motor to drive it at a second constant speed, is provided to drive said motor at at least each of said two speeds during each said cycle and at one of such constant speeds during a portion of each cycle of the assembly which includes a portion of the dwell period.
- a continuously driven, rotary motor, operable when driven to drive said assembly to effect the mold open and mold closed positions;
Specification