Semi-automatic apparatus for molding plastic copings and similar articles

Claim 2

Apparatus for forming plastic dental copings, models, splints, guards, trays and the like comprising a support, a receptacle to removably retain male dies, a holder to removably retain a plastic sheet, resilient means urging said holder above said receptacle, a heater, manually operable means rotatably mounting said heater on said support for movement from an inoperative position to an operative position directly above said holder to soften the plastic sheet, a dome mounted on said support above said holder, pneumatic means to reciprocate said dome vertically from an upper inoperative position to a lower operative position in contact with said holder to compress said resilient means and cause the plastic sheet to engage the male dies, a normally closed conduit from a source of air under pressure to said dome, said pneumatic means normally holding said dome in its upper inoperative position, means causing said pneumatic means to lower said dome into its operative position only when said heater is moved into its inoperative position, and means to open said conduit when said dome is in its operative position to apply air pressure through said dome over saId plastic sheet and cause the plastic sheet to drape over the male dies, said pneumatic means including a cylinder having a piston and piston rod reciprocable therein, means securing said piston rod to said dome externally of said cylinder, a pneumatic circuit from a source of air under pressure to the top and bottom of said cylinder and a first valve in the circuit normally closing off communication to the top of said cylinder and keeping communication open to the bottom thereof, said means causing said pneumatic means to lower said dome including a cam finger on said means rotatably mounting said heater and a second normally closed one-way tripping lever valve in said pneumatic circuit actuatable by engagement with said cam finger only when said heater is in its inoperative position to open the same and cause the first valve to open communication to the top and close it to the bottom of said cylinder and thus lower said dome.

Claim 3

The apparatus of claim 1 and a normally closed second conduit from a source of vacuum to said receptacle and means to open said second conduit when said dome is in its operative position.

Claim 4

The apparatus of claim 1 and a third normally closed manually operable valve in the pneumatic circuit which when actuated will return said first valve to its original position closing off communication to the top of said cylinder and opening communication to the bottom thereof to raise said dome to its inoperative position.

Claim 5

The apparatus of claim 1 wherein said means to open said conduit from the source of air under pressure to said dome includes a normally closed tripping valve operatively connected in said conduit and carried by said support and actuatable by contact with said means securing said piston rod to said dome when said dome is in its lower operative position.

Claim 6

The apparatus of claim 4 and a normally closed second conduit from a source of vacuum to said receptacle and means to open said second conduit when said dome is in its operative position.

Claim 7

The apparatus of claim 5 wherein said means to open said second conduit from the source of vacuum to said receptacle includes a normally closed tripping valve operatively connected in said second conduit and carried by said support and actuatable by contact with said means securing said piston rod to said dome when said dome is in its lower operative position.

Claim 8

In apparatus for forming plastic dental copings, models, splints, guards, trays and the like including a housing having an upper wall, a receptacle to removably retain male dies removably mounted on said wall, a holder to removably retain a plastic sheet mounted above said receptacle for vertical movement to and from said receptacle, a pressure dome above said holder, at least one post extending through said wall secured at its upper end to said dome and having a lower end disposed in said housing and pneumatic means operatively connected to the lower end of said post to raise said dome to an inoperative position above said holder and lower it to an operative position against said holder and in turn against said receptacle to enclose the plastic disk and male dies; a heater, a post securing said heater adjacent its upper end and extending rotatably through said housing wall, said pneumatic means normally acting to raise said dome to its inoperative position, a first valve means coactive between said lower end of said heater post and said pneumatic means to cause it to lower said dome to its operative position only when said heater is rotated from an operative position directly above said holder to an inoperative position to one side of said holder, a normally closed conduit from a source of air under pressure to said dome, and a second valve means coactive between the lower end of said dome post and said conduit to open said conduit and deliver air under pressure to said dome only when said dome is in its lower operative position, said pneumatic means including a cylinder having a piston and piston rod reciprocable therein, a bar connecting the lower end of said dome post to said piston rod externally of said cylinder, a pneumatic circuit from a source of air under pressure to the top and bottom of said cylinder and a master valve in the circuit normally closing off communication to the top of said cylinder and keeping communication open to the bottom thereof, the first valve means including a cam finger at the lower end of said heater post and a first one-way normally closed tripping lever valve secured in said housing and operatively connected in said pneumatic circuit actuatable by engagement with said cam finger, when said heater is rotated to its inoperative position, to open said tripping lever valve and cause said master valve to open communication to the top of said cylinder and close communication to the bottom thereof to lower said dome to its operative position.

Claim 9

In apparatus for forming plastic dental copings, models, splints, guards, trays and the like including a housing having an upper wall, a receptacle to removably retain male dies removably mounted on said wall, a holder to removably retain a plastic sheet mounted above said receptacle for vertical movement to and from said receptacle, a pressure dome above said holder, at least one post extending through said wall secured at its upper end to said dome and having a lower end disposed in said housing and pneumatic means operatively connected to the lower end of said post to raise said dome to an inoperative position above said holder and lower it to an operative position against said holder and in turn against said receptacle to enclose the plastic disk and male dies; a heater, a post securing said heater adjacent its upper end and extending rotatably through said housing wall, said pneumatic means normally acting to raise said dome to its inoperative position, a first valve means coactive between said lower end of said heater post and said pneumatic means to cause it to lower said dome to its operative position only when said heater is rotated from an operative position directly above said holder to an inoperative position to one side of said holder, a normally closed conduit from a source of air under pressure to said dome, and a second valve means coactive between the lower end of said dome post and said conduit to open said conduit and deliver air under pressure to said dome only when said dome is in its lower operative position, said pneumatic means including a cylinder having a piston and piston rod reciprocable therein, a bar connecting the lower end of said dome post to said piston rod externally of said cylinder, a pneumatic circuit from a source of air under pressure to the top and bottom of said cylinder and a master valve in the circuit normally closing off communication to the top of said cylinder and keeping communication open to the bottom thereof, the first valve means including a cam finger at the lower end of said heater post and a first one-way normally closed tripping lever valve secured in said housing and operatively connected in said pneumatic circuit actuatable by engagement with said cam finger, when said heater is rotated to its inoperative position, to open said tripping lever valve and cause said master valve to open communication to the top of said cylinder and close communication to the bottom thereof to lower said dome to its operative position.

Claim 10

The apparatus of claim 7 and a handle pivotally secured to said heater post above said housing wall for movement vertically towards and away from said wall and spaced pins alternately engageable in a through hole provided in said handle to retain said heater selectively in its operative and inoperative positions.

Claim 11

The apparatus of claim 7 wherein said second valve means includes a second normally closed tripping lever valve engageable with said bar at the lower end of said dome post, when said dome is in its lower operative position, to open said second tripping lever valve and thus open said conduit from the source of air under pressure to said dome.

Claim 12

The apparatus of claim 9 and a second normally closed conduit from a source of vacuum to said receptacle and a third normally closed tripping lever valve engageable with said bar at the lower end of said dome post, when said dome is in its lower operative position, to open said third tripping lever valve and thus open said second conduit from the vacuum source to the receptacle simultaneously with the opening of said second tripping lever valve.

Claim 13

The apparatus of claim 7 wherein said master valve is a four-way valve and a further manually operable normally closed valve in said pneumatic circuit which when actuated to the open position when the dome is in its lower operative position will cause said master valve to return to its original position closing off communication to the top of said cylinder and opening up communication to the bottom of said cylinder to raise said dome to its inoperative position after molding of said plastic disk on said male dies is completed.