Thermoforming apparatus

Claim 2

A control system for a thermoforming apparatus, comprising control means for controlling a plurality of operations of said apparatus in a predetermined sequence, programming means for receiving a programming medium movable along a guideway thereof, driving means for moving said medium aloNg said guideway at a predetermined constant speed, an energization circuit for said driving means, a plurality of switching means responsive to the position of said programming means along said guideway and connected to said control means to operate said apparatus in said predetermined sequence and to control the duration of at least one of said operations in response to the speed of said medium and the spacing of ones of said switches along said guideway, a plurality of sensing devices mounted in said thermoforming apparatus for sensing conditions therein and, when activated, for interrupting said energization circuit to stop the movement of said programming medium until a predetermined condition is sensed, and circuit means interconnecting respective ones of said switching means and said sensing devices for selectively activating said sensing devices during predetermined ones of said plurality of operations.

Claim 3

The combination of claim 1 in which at least one of said sensing devices includes a limit switch.

Claim 4

The combination of claim 1 in which at least one of said sensing devices includes a heat sensing device.

Claim 5

The combination of claim 1 further comprising: a carriage for a heat screen mounted within said thermoforming apparatus; a heat screen mounted to said carriage; third means for driving said heat screen; said control means including a means for actuating said heat screen carriage driving means in response to the closing of one of said switches and sensing devices.

Claim 6

The combination of claim 4 further including a program card serving as said medium and having engageable surfaces positioned in rows, said engageable surfaces actuating said one of said switching means as said program card is driven through said guideway.

Claim 7

The combination of claim 5 in which different engageable surfaces on said card control the time of operation of individual portions of said thermoforming apparatus.

Claim 8

The combination of claim 5 in which one of said switching means engaged by one of said engageable surfaces starts an operation within said thermoforming apparatus and a sensing device terminates the operation.

Claim 9

The combination of claim 6 including means for starting an operation of said thermoforming apparatus upon the actuation of one of said sensing devices and terminating said operation upon the actuation of one of said program switches.

Claim 10

A combination of a thermoforming apparatus with a programming unit that controls the operation of the thermoforming apparatus in accordance with a program recorded on a medium in the form of engageable surfaces thereon, comprising: a guideway adapted to receive said medium; program driving means for moving said medium along said guideway; a plurality of program switches in said guideway, positioned to be actuated by said engageable surfaces of said medium; a plurality of sensing devices including limit switches mounted to said thermoforming apparatus for sensing conditions therein; first means connected to said program switches and sensing devices for controlling operations of said thermoforming apparatus in response to the actuation of said program switches and sensing devices; second means connected to said program switches and sensing devices for controlling the energization of said program driving means, a carriage for a heat screen mounted within said thermoforming apparatus; a heat screen mounted to said carriage; third means for driving said heat screen; said first means including a means for actuating said heat screen carriage driving means in response to the closing of one of said switches and sensing devices, a program card serving as said medium and having engageable surfaces positioned in rows, said engageable surfaces actuating said program switches as said program card is driven through said guideway, different engageable surfaces on said card controlling the time of operation of individual portions of Said thermoforming apparatus, said first means includes means for starting an operation of said thermoforming apparatus upon the actuation of one of said sensing devices and terminating said operation upon the actuation of one of said program switches, said second means includes a means for stopping said program driving means in response to the actuation of one of said program switches and for starting said program driving means in response to the actuation of one of said sensing devices, a clamping carriage for holding a sheet of plastic; heating elements for heating said sheet of plastic; said means for controlling said thermoforming apparatus including means for causing heat from said heating elements to impinge upon said plastic and for causing said heat screen to partially shield said plastic at least over a portion of the cycle of use of the thermoforming apparatus; at least one plunger and one mold cavity; means controlled by said programming unit to move said clamping mechanism adjacent to one of said plunger and mold cavities; means for bringing said one plunger and mold cavity together under the control of said programming unit; a source of pressurized gas; means for connecting said pressurized gas to said mold cavity in response to the closing of one of said program switches, whereby said plastic sheet in said clamping means is caused to billow outwards; a photocell sensing means for sensing the height of billowing of said plastic sheets; said photocell sensing device including one of said limit switches; said first means and second means including a means for energizing the motor of said programming apparatus and for disconnecting said source of pressurized gas from said cavity in response to the closing of said one limit switch; and said first means including a means for moving said plunger into said mold cavity in response to the closing of another of said program switches.

Claim 11

A combination of a thermoforming apparatus with a programming unit that controls the operation of the thermoforming apparatus in accordance with a program recorded on a medium in the form of engageable surfaces thereon, comprising: a guideway adapted to receive said medium; program driving means for moving said medium along said guideway; a plurality of program switches in said guideway, positioned to be actuated by said engageable surfaces of said medium; a plurality of sensing devices including limit switches mounted to said thermoforming apparatus for sensing conditions therein; first means connected to said program switches and sensing devices for controlling operations of said thermoforming apparatus in response to the actuation of said program switches and sensing devices; second means connected to said program switches and sensing devices for controlling the energization of said program driving means, a carriage for a heat screen mounted within said thermoforming apparatus; a heat screen mounted to said carriage; third means for driving said heat screen; said first means including a means for actuating said heat screen carriage driving means in response to the closing of one of said switches and sensing devices, a program card serving as said medium and having engageable surfaces positioned in rows, said engageable surfaces actuating said program switches as said program card is driven through said guideway, different engageable surfaces on said card controlling the time of operation of individual portions of Said thermoforming apparatus, said first means includes means for starting an operation of said thermoforming apparatus upon the actuation of one of said sensing devices and terminating said operation upon the actuation of one of said program switches, said second means includes a means for stopping said program driving means in response to the actuation of one of said program switches and for starting said program driving means in response to the actuation of one of said sensing devices, a clamping carriage for holding a sheet of plastic; heating elements for heating said sheet of plastic; said means for controlling said thermoforming apparatus including means for causing heat from said heating elements to impinge upon said plastic and for causing said heat screen to partially shield said plastic at least over a portion of the cycle of use of the thermoforming apparatus; at least one plunger and one mold cavity; means controlled by said programming unit to move said clamping mechanism adjacent to one of said plunger and mold cavities; means for bringing said one plunger and mold cavity together under the control of said programming unit; a source of pressurized gas; means for connecting said pressurized gas to said mold cavity in response to the closing of one of said program switches, whereby said plastic sheet in said clamping means is caused to billow outwards; a photocell sensing means for sensing the height of billowing of said plastic sheets; said photocell sensing device including one of said limit switches; said first means and second means including a means for energizing the motor of said programming apparatus and for disconnecting said source of pressurized gas from said cavity in response to the closing of said one limit switch; and said first means including a means for moving said plunger into said mold cavity in response to the closing of another of said program switches.